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OCTOBER 1941 THE ANALYST Vol. 66 No. 787 PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS The Determination of Metals by Means of S-Hydroxyquinoline The Examination of Oxine Precipitates using X-ray Diffraction Methods* BY R. C. CHIRNSIDE F.I.C. CELIA F. PRITCHARD B.Sc. A.I.C. AND H. P. ROOKSBY B.Sc. F.INsT.P. (Read at the Meeting M a y 7 1941) INTRODUCTION.-The use of 8-hydroxyquinoline for the precipitation of a number of metals is now a well-established procedure. In particular magnesium aluminium and zinc are frequently determined either by weighing the oxine complex of the metal or by bromometric titration of the precipitate. The conditions for the use of this reagent were worked out by Berg1 and by Hahn and Vieweg,2 and some work was carried out in this country by Fleck and Ward.3 A disadvantage of the reagent is its non-specificity; nearly all of the commoner metals and some that are not so common can be precipitated by a suitable adjustment of the conditions.In some instances the precipitation is quantitative in others only partly so. Some years ago the literature included many examples of failure to recognise the limitations of the reagent and some of the separations outlined are not in fact practicable. It is true that in a solution of a certain metal precipitation might be complete over one range of pH and with another metal over a different range of pH so that a separation of a mixture of the two metals should theoretically be possible over that part of the pH range not common to them.Fleck and Ward determined the range of pH for the precipitation of a number of metals and indicated a number of such separations which should be possible, but wisely added the proviso that they might not be possible in practice because of “the formation of mixed crystals.” We have sought to use this reagent in the analysis of glass, more particularly complex glasses containing in addition to the usual constituents boron, zinc and phosphorus. In a paper by one of us the successful but limited application for this purpose was described and the opportunity was taken to stress the impracticability of realising many of the theoretical separations to which we have referred. About that time it became evident that workers of repute were making similar discoveries. Knowless summed up the position very aptly when he said “the value of oxine as a reagent in quantitative analysis lies principally though not entirely in its use after prelimiuary separations have removed interfering elements.” The use of the reagent during the last few years has been mainly in determinations of magnesium and aluminium.The realisation in practice of some of the separations theoretically possible has been our aim for some years but the feeling that the co-precipitations were in fact due to the formation of mixed crystals or solid solution persisted in our minds. Among the most * Communication from the Staff of the Research Laboratories of The General Electric Company, Limited England. 39 400 CHIRNSIDE PRITCHARD AND ROOKSBY THE DETERMINATION OF METALS BY MEANS stimulating papers to come to our notice was one by Moyer and Remington,s who put forward the view that in separations of zinc from magnesium and of aluminium from iron, co-precipitation might in fact be due to adsorption effects and curves were shown from which it was deduced that co-precipitation was in accordance with Freundlich’s adsorption equation.We were at the time examining some other aspects of the oxine precipitates and it was decided to include an examination of Moyer and Remington’s work in the scope of our investigation as it was to some extent complementary. The first part of the work now described is concerned with the state of a number of the oxine complexes after drying at various temperatures. We have always preferred to determine the oxine precipitates gravimetrically ; the volumetric procedure does not seem to offer any advantage except perhaps where large numbers of determinations are to be made.But it is essential in the gravimetric method to dry the material at such a temperature that a compound of fixed composition will be obtained and moreover to know what that composition is. The drying temperature recommended for particular metal-oxine com-plexes differs in the published methods especially when the precipitates are to be weighed in the hydrated condition. It was hoped as a result of our work to obtain more precise information concerning the composition of some of these hydrates and to ascertain the correct temperatures for drying them to a fixed composition. The second part of the paper is concerned with our investigations into the nature of co-precipitated oxine complexes with particular reference to Moyer and Remington’s work.In both parts of our investigation use has been made of the X-ray diffraction method of analysis. This method is frequently used in these Laboratories to supplement or in some instances to replace the more usual methods of analysis. Since references to it in analytical literature are few it may be of interest at this point briefly to describe the technique of the method. A fuller description of the method and its applications has been given elsewhere.7~~ ANALYSIS BY THE X-RAY DIFFRACTION METHoD.-The diffraction of a beam of X-rays by the regularly arranged planes of atoms constituting the space lattice of a crystalline substance takes place according to an equation nX = 2d sin 8.A is the wave-length of the rays d is the interplanar distance 28 is the angle through which the incident beam is deflected and n is an integer. The diffraction effects may be examined in several ways. In the method here used which is generally referred to as the powder method the substance is in the form of a fine powder and the incident X-ray beam restricted by a collimating system to a narrow pencil is monochromatic. For any selected set of atomic planes some of the particles constituting the powder will be at the correct angle for diffraction to be effected in accordance with the above equation and the diffracted rays take the form of a cone, Similarly a diffraction cone results from every other set of atomic planes comprising the structure of the crystalline substance.A photographic film placed to intercept the diffracted rays will therefore show a series of concentric circles. In practice a narrow strip of film is usually employed disposed radially so that only restricted portions of the rings are recorded and the diffraction pattern consists of a number of slightly curved lines across the film. Since no two different chemical substances have exactly the same crystal structure or arrangement of atoms in space it will be apparent that the powder diffraction pattern is unique for each substance. In inorganic chemical analysis the X-ray pattern has frequently been employed as a means of identification of a particular chemical compound, and in a mixture containing several elements the actual phases occurring may be dis-tinguished.As an elementary example the method may be used to differentiate between a mixture of sodium chloride and potassium bromide and a mixture of sodium bromide and. potassium chloride. Changes of phase such as are produced by dehydration of a hydrated salt are conveniently followed by observation of the changes in the X-ray diffraction patterns. When two substances crystallise in the same manner or in other words are isomorphous they are frequently continuously soluble one in the other. The lattice dimensions of the substances and their solid solutions which change in a systematic manner determine the positions of the lines on the X-ray photographs. The patterns of the individual substances are usually similar in appearance; a similar series of lines occurs in each instance but will be more widely spaced for the substance whose lattice parameters are the smaller and for the solid One other important feature of X-ray patterns must be mentioned here OF 8-HYDROXYQUINOLINE THE EXAMINATION OF OXINE PRECIPITATES 401 solutions the X-ray lines will occur at intermediate positions.It is frequently possible to make observation of solid solution effects when only small changes in composition are involved ; for example with sufficiently good technique the displacements of the X-ray lines produced by a change of a fraction of a per cent. in the composition of an alloy of two metals may often be measured. The study of organic substances by X-ray methods is also possible although the generally more complex nature of organic structures involves greater difficulty in the inter-pretation of the powder patterns.Whilst the molecule has little significance in most inorganic structures it is a real factor in organic chemistry with the consequence that the powder photograph may include the effects of periodicities of both atomic and molecular origins. The X-ray patterns are frequently characterised by a multiplicity of lines and for closely related compounds may be difficult to distinguish. The changes in the X-ray patterns accompanying solid solution effects are likely to be extremely small. They may be the more readily observed by the employment of a camera of large diameter and a comparatively long X-ray wave-length; in this way a large dispersion of the X-ray lines is obtained.In the camera used for much of the work to be described a strip of film is held by means of a steel spring on a cylindrical frame of diameter 19 cm. The powdered specimen is attached to a fine glass fibre by means of seccotine and the fibre is held in a chuck so that it lies along the axis of the camera. The chuck is continuously rotated during the exposure so as to. expose a truly representative number of each of the crystal faces. The air in the camera is displaced by hydrogen to reduce general X-ray scatter and so increase the clarity of the X-ray negative. The radiations which have been employed in different instances are CuKa CoKa CrXa obtained by filtration by appropriate elements of the rays from Cu Co and Cr targets respectively.(1) COMPOSITION OF OXINE COMPLEXES DRIED AT VARIOUS TEMPERATURES. EXPERIMENTAL.-(a) Magutesizcm.-Magnesium was precipitated as the oxine complex from ammoniacal solution. To a hydrochloric acid solution containing approx. 50 mg. of magnesium were added 5 g. of ammonium chloride and 30 ml. of 2 per cent. oxine solution in 2 N acetic acid. The solution was heated to boiling and made alkaline with ammonia. It was then allowed'to stand for 10 minutes before filtration of the oxine precipitate on a sintered glass crucible. The precipitate was washed with hot water and dried to constant weight at a number of temperatures 98" C. (water oven) 110" C. 140" C. and 160" C. Weighings were carried out at half-hourly or hourly intervals and a small sample was taken at each stage for X-ray analysis.The results are given in Table I and it will be seen that magnesium forms a dihydrate, Mg(C,H,0N),.2H20 which is reasonably constant in weight at 110" C. after 24 hours, TABLE I EFFECT OF DRYING METAL OXINATE PRECIPITATES AT VARIOUS TEMPERATURES Metal Dried at For Wt. of ppt. Wt. of metal Wt. of metal Calculated 0.8248 0-0570 0-0568 Dihydrate Theoretical Found OC. hours g g. g- as 0.8222 9 0.0567 3* 2* 0.8002 # 0.0623 Anibdrous 160 !* 0.7364 ,# 0.0573 2, Mg { ;:! 0.4812 0.0808 0.0807 Dihydrate 0.4394 3 0.0814 Anhydrous 0-4386 3 0.0812 0-4362 ,> 0.0807 3 2 1.3413 0.081 7 0.0'787 1 , 1.3408 2 0.0787 #, 1.3404 1 ) 0.0787 ,, 1.3386 7 0.0786 2 0.2218 I 0.0255 a , 2 98 ,I P Y 14 c ;;: A1 i ;i 23* 3 ? J 98 1 0.2226 0.0257 0-0256 1 , Fe { ;: 2 0.2220 ,> 0.0255 ,I and at 98" C.after drying for a considerably longer period. A recommendation for example, to dry this precipitate in a steam-oven for 1 hour before weighing as the hydrate would therefore give rise to an appreciable error I t is possible that in some instances a smal 402 CHIRNSIDE PRITCHARD AND ROOKSBY THE DETERMINATION OF METALS BY MEANS amount of 8-hydroxyquinoline is precipitated with the metallic oxinates and that this is gradually volatilised during the drying process at a rate dependent on temperature and time. The anhydrous magnesium complex is usually stated to be formed on heating the precipitate to 130"-140" C. but our results show that at this temperature complete con-version to the anhydrous state has not been effected even after 5+ hours' heating.Only after heating at 160" C. does the weight of magnesium calculated from the anhydrous composition agree with the theoretical and with that calculated on the dihydrate com-position after drying at 110" C. These conclusions are substantiated by the X-ray patterns of the precipitates dried at the various temperatures. Fig. 1 shows that after drying to constant weight at 98" and 110" C. the patterns are identical. At 140" C. there are two phases visible; only partial conversion to the anhydrous state having been achieved and at 160" C. only one phase that of the anhydrous compound is visible. The practical point that emerges is that the most reliable results from a gravimetric determination of magnesium as oxinate are likely to be obtained by drying the precipitate to the anhydrous form at 160" C.and that errors attributed to other causes may frequently be connected with inadequate drying. To a neutral solution containing approx. 80 mg. of zinc as chloride were added 5 g. of sodium tartrate and 20 ml. of N sodium hydroxide solution. The solution was heated to boiling, and the zinc was precipitated by addition of 30 ml. of a 2 per cent. alcoholic solution of oxine. The precipitate was filtered and washed as above and dried to constant weight at various temperatures. It will be seen that a s with magnesium the precipitate can be weighed as the dihydrate after drying at 98" C. but at 110" C. the complex differs from that of magnesium in that it is substantially dehydrated.At 140" C. there is little further measurable change but at 160" C. the weight is closest to theoretical. These changes can be followed in the X-ray photographs (Fig. 2) which show almost complete decomposition of the dihydrate into an "amorphous" phase a t 110" C. very little further change at 140" C. save the presence of a small amount of a new crystalline phase and finally at 160" C. the complete conversion of the dihydrate to a crystalline anhydrous form. The slightly high results at 110" C. are therefore asso-ciated with residual dihydrate and at 140" C. presumably with the retention of water by the anhydrous form in the amorphous condition. The 'X-ray results clearly show that the hydrate of the zinc complex is much more readily decomposed than that of magnesium since there is still a trace of hydrate phase present after heating the magnesium complex at 140" C.This phase has almost gone from the pattern of the zinc complex at 110" C. The practical point emerging is that instructions in an analytical procedure need to be more precise than say "dry at 100" C."; the hydrated form may possibly be retained by drying in a steam oven but the more certain procedure is to dry to the anhydrous form at 160" C. Comparison of the X-ray patterns obtained from the magnesium and zinc oxinates reveals the similarity in structure and the two complexes are clearly isomorphous. This is of interest in considering the possibility of separating the two metals by means of oxine. The structure is evidently determined largely by the organic part of the molecule the differences between the zinc and magnesium atoms causing only relatively small shifts in the positions of the X-ray lines.Aluminium.-Similar experiments were made with solutions containing aluminium. To a hydrochloric acid solution containing approx. 80 mg. of aluminium were added 5 g. of ammonium acetate and the solution was made ammoniacal to bromocresol purple. Thirty ml. of 2 per cent. oxine in 2 N acetic acid were then added and the solution was heated to boiling. The precipitate was washed and filtered and the drying procedure was carried out as before. The results in Table I show that the aluminium complex is obtained in the anhydrous form by drying at 98" C. and that there is no particular advantage save that of speed in drying at higher temperatures.The X-ray patterns confirm that no change of phase takes place between 98" and 160" C. (d) Iron.-Similar experiments were made with iron solutions. The iron was precipitated with an acetic acid solution of oxine from a tartaric acid solution buffered with ammonium acetate the solution having a PH of 4.1. The results obtained in the (b) Zinc.-Similar experiments were carried out on solutions containing zinc. The results are given in Table I. (c 98' C. 110' c. 140' C. 160' C. X-Ray Powder Photographs of Zinc Oxinate Precipitates dried at various Temperatures. (12 cm. diameter Camera. Cu Kcr Radiation.) Fig. 1. 98' C. 110' c. 140' C. 160' C. X- Ray Powder Photographs of Magnesium Oxinate Precipitates dried at various temperatures.(12 cm. diameter Camera. Cu Kor Radiation.) Fig. 2 Zn X-Ray Powder Photographs comparing co-precipitated Magnesium-Zinc Oxinate with pure Magnesiuiii and Zinc Oxinates. (19 cm. diameter Camera. Cr IGx Radiation.) Fig. 3. 1 1Fe A1 1 3 Fe:Xl 2 10 Fe:-41 A1 X-Ray Powder Photographs comparing co-precipitated Iron-Aluminium Osinates with pure Iron and *4luminium Oxinates. (19 cm. diameter Camera. Cr Ka Radiation.) Fig. 4 OF 8-HYDROXYQUINOLINE THE EXAMINATION OF OXINE PRECIPITATES 403 drying experiments were similar to those obtained with aluminium. The oxinate is readily obtained in the anhydrous form at 98" C. Although from other considerations the oxine complexes of iron and aluminium might have been expected to be isomorphous no similarity in structure is in fact indicated by the X-ray patterns.CO-PRECIPITATION OF OXINE PRECIPITATES.-It has been our experience that where two metals are present in a solution the fiH of which is such that only one of the metals should be precipitated with hydroxyquinoline the other metal is frequently precipitated in part or in whole. Many separations which should from an examination of the $H range of precipitation of the various metals be possible are not in fact practicable. Much published work fails to take adequate notice of these facts but the implications have been understood by some workers notably by Knowles of the Bureau of Standards, whose conclusions have already been mentioned and by Fleck and Ward who suggested the possibility of the formation of mixed crystals.Moyer and Remington recognised the limitations of the separations in certain instances viz. zinc from magnesium and iron from aluminium and ascribed this fact of co-precipitation to adsorption of one complex on the other. Our own views were that the formation of mixed crystals or solid solutions was the more likely explanation but it was decided to investigate this point more fully for if the troubles were found to be due to adsorption there might be some means of minimising this so as to effect reasonable separations. If on the other hand solid solutions were formed no obvious remedy was available. Here again as in the hydration problem the X-ray diffraction technique is the ideal method of investigation. For the purposes of the investigation the two pairs of metals studied by Moyer and Remington were used vix.zinc and magnesium and iron and aluminium. Fleck and Ward found that zinc is quantitatively precipitated from acetate solution over the range $H 4.6 to 13.4 and is partially precipitated between $H 4 and 14. For magnesium the corresponding ranges were found to be pH 9.5 to 12-7 and fiH 7.3 to 13.2. Separations of zinc and magnesium would therefore appear to be possible between j5H 4.0 and 7.3 but Moyer and Remington found that co-precipitation of magnesium with zinc begins at 2 $H units below that indicated by Fleck and Ward's curves so that complete separation is restricted to the narrow range pH 4.6 to 5-5. In order to investigate the mechanism of the co-precipitation of complexes Moyer and Remington precipitated zinc from a solution containing zinc and magnesium at fiH 5-9 at which point co-precipitation of magnesium has just begun.The weight of zinc was kept constant and the weight of magnesium oxinate carried down per gram of zinc was plotted against the weight of magnesium in solution. This it was claimed gave a typical adsorption isotherm and it was concluded that co-precipitation was probably due to adsorption of the magnesium complex on that of the zinc. Similarly with iron and aluminium Gotas found that aluminium is precipitated over the range fiH 4-2 to 9.8 and ferric iron over the range +H 2.8 to 11.2 but Moyer and Remington found that an effective separation could only be made between j5H 3.5 and 4-0. Co-precipitation was investigated at $H 4.1 and again it was concluded that precipitation of the aluminium was due to adsorption.As has been indicated our own view was that the co-precipitation was associated with the formation of mixed crystals or solid solution. It was first necessary therefore in our investigation t o establish that solid solutions of the respective pairs of oxinates could be formed. For this purpose co-precipitations were carried out at pH values at which both metals were quantitatively ,precipitated. Secondly an endeavour was made to repeat the experiments of Moyer and Remington, and to investigate the precipitates obtained by X-ray diffraction methods. This would show whether an oxinate precipitated at a pH at which it would not normally be precipitated if present in solution alone was in solid solution with the other oxinate or whether it was adsorbed on it.In the latter event the X-ray pattern should reveal a simple mixture of the two complexes. To a hydrochloric acid solution con-taining equivalent proportions of zinc (16 mg.) and magnesium (6 mg.) were added 20 ml. of N sodium hydroxide solution and 2 g. of tartaric acid. Forty ml. of 3 per cent. oxine solution in N/5 hydrochloric acid were added and the solution was heated to boiling (2) EXPERIMENTAL.-~~UC and Nagrtesi.um.-(i 404 CHIRNSIDE PRITCHARD AND ROOKSBY THE DETERMINATION OF METALS BY MEANS and filtered after standing for ten minutes on a sintered glass crucible. The $H of the filtrate was 11.0. The precipitate was dried at 98" C. and examined by X-ray methods.In Fig. 3 the X-ray patterns of the co-precipitated oxinate and of the individual mag-nesium and zinc oxinates are compared. A series of solutions containing zinc and magnesium was made up in which the amount of zinc was kept constant (50mg.) and the amounts of magnesium were varied from 1.25 mg. to 25 mg. Precipitation was carried out in ammonium acetate and acetic acid solution the PH being adjusted to 5-9 by addition of 2 N sodium hydroxide solution, and the final volume being made up to 150ml. in each instance. The precipitates were dried at l6OoC. and weighed. The amount of zinc was constant and the amount of magnesium carried down with the zinc complex and the amount remaining in solution could therefore be calculated (Table 11).The results were checked in a few instances by making the filtrate ammoniacal and determining the amount of magnesium left in solution. The precipitates used for the X-ray examination were obtained from duplicate tests in which the drying was carried out at 98" C. in order to retain the dihydrate form this being the condition in which co-precipitation took place. TABLE I1 CO-PRECIPITATION OF ZINC AND MAGNESIUM OXINATES AT pH 5-9 (ii) Zn oxinate g 0.2702 [0.0500 Zn] > J J J J > J J J B J D Mg oxinate g 0.0161 0-00125Mg 0-0322 E 0-0025Mg 0-0646 0-0050Mg (0.44) 0-0968 = 0.0075Mg (0.66) 0-1290 0.0100Mg 0.1936 =- 0-0150Mg (1.32) 0-2582 G 0.0200Mg (1-76) 0.3228 = 0-0250Mg (0.11) (0.22) (0.88) (2.20) Theoretical, total oxinate g 0.2863 0.3025 0-3347 0-3670 0.3992 0-4637 0-5282 0-6927 Found, total oxinate g 0-2822 0.2916 0.3092 0.3278 0.3344 0.3652 0-3932 0-4244 Mg oxinate pptd.(by diff .) g-0.0120 (0.04) 0.0214 0.0390 0.0576 0-0642 (0-24) 0-0950 (0-35) 0.1232 (0.46) 0.1542 (0.57) (0.08) (0.14) (0.21) The figures in brackets Col. 2 represent the weight of Mg oxinate per litre of solution. In Col. 5 they represent the weight of Mg oxinate precipitated per 1 g. of Zn oxinate. Iron and AZuuminiztm.-(i) Since there was no obvious similarity between the X-ray patterns of the iron and aluminium "oxinates" several precipitates containing different ratios of iron to aluminium were examined. Solutions containing aluminium and iron in increasing atomic proportions of aluminium viz.1 1 2 1 3 1 4 1 and 10 1, were treated with oxine. The solutions which contained ammonium acetate and acetic acid were adjusted to j5H 4.8 to 5.0 and the precipitates were dried at 98" C. and examined by X-ray methods. The X-ray patterns of the iron and aluminium oxinates and those of the co-precipitated complexes are compared in Fig. 4. A series of solutions containing iron and aluminium was prepared similar to those of zinc and magnesium in which the amount of iron was-kept constant at 10 mg. and that of the aluminium was varied from 0-25 mg. to 7 mg. Precipitation was carried out in ammonium acetate and tartaric acid solution the fiH being adjusted to 4.1 by the addition of N hydrochloric acid and the final volume being made up to 150 ml.in each instance. The precipitates were dried at 110" C. and weighed and the amount of aluminium oxinate precipitated with that of the iron and the amount remaining in solution was calculated for each test (Table 111). DISCUSSION OF REsuLTs.-The X-ray patterns (Figs. 3 and 4) show that when zinc and magnesium or iron and aluminium are precipitated together from a solution the PH of which is such that quantitative deposition of either metal is effected the precipitate obtained can be regarded as a solid solution of one complex in the other. With zinc and (ii) (3 OF 8-HYDROXYQUINOLINE THE EXAMINATION OF OXINE PRECIPITATES 405 magnesium a continuous series of solid solutions is formed when the ratio of the amounts of the two metals in solution is varied.This is to be expected since the hydrated zinc and magnesium complexes have been found as a result of the work described earlier in the paper to be isomorphous. With iron and aluminium where the X-ray evidence indicates that the complexes are not isomorphous a change of phase occurs when the aluminium to iron ratio is ap-proximately 2 1. The iron complex becomes saturated with the aluminium complex at about this point and subsequent increases in the proportion of aluminium lead to the formation of the free aluminium complex in addition to the solid solution product thus giving rise to two phases. In the X-ray photographs reproduced in Fig. 4 it may be observed that the lines of the aluminium complex occur faintly in the 3 1 precipitate and strongly in the 10 1 precipitate.When the precipitation is carried out at a+H at which only one of each of the pairs of metals under consideration shouldaormally be precipitated co-precipitation of the other metal may in fact occur and the X-ray patterns show that here too solid solution takes place. TABLE I11 CO-PRECIPITATION OF IRON AND ALUMINIUM OXINATES AT pH 4.1 Fe oxinate g-0.0900 [O.OlOO Fe] > J J > J J A1 oxinate g 0.0170 0-0010Al (0.113) 0.0340 = 0.0020Al (0.226) 0-0510 0.0030Al (0.339) 0.0680 = 0-0040Al (0.452) 0-0850 G 0.0050Al (0.565) 0.1020 = 0.0060Al (0.678) 0.1190 = 0-0070Al (0-7 9 1) Theoretical , total oxinate g 0.1070 0-1240 0.1411 0.1582 0.1752 0.1922 0.2092 Found, total oxinate g 0.1044 0-1108 0.1192 0.1250 0.1300 0.1330 0.1364 A1 oxinate pptd.(by diff .) g. 0.0144 (0.16) 0.0208 (0.23) 0.0292 (0.32) 0,0350 (0.39) (0.44) 0.0430 (0.48) 0.0464 (0-52) a.0400 The figures in brackets in Col. 2 represent the weight of A1 oxinate per litre of solution. In Col. 5 they represent the weight of A1 oxinate precipitated per 1 g. of Fe oxinate. The amounts of the co-precipitated metals have been determined as shown in Tables I1 and 111 and an attempt has been made to fit them to curves similar to those of Moyer and Remington but so far as can be seen there is no evidence that an adsorption law of the type indicated by Moyer and Remington is followed. Indeed the results we have obtained show merely that the greater the concentration of magnesium or aluminium in their respective solutions the greater the amounts co-precipitated with either zinc or iron.In the course of the preparation of precipitates suitable for X-ray examination an improvement in the definition of the lines was obtained when the precipitates were “aged” for an hour or more before filtration. The improved sharpness of the X-ray pattern indicative of larger or more perfect crystals was of great assistance in diagnosing solid solution effects. A marked improvement was observed when the “ageing” period was increased from 10 minutes to 4 hours with both magnesium-rich and iron-rich precipitates but no further advantage was observed with longer periods of “ageing.” In the course of these “ageing” experiments it was found that the composition of certain of the iron and aluminium precipitates filtered immediately after precipitation differed from that obtaining when they were filtered after “ageing” for 30 minutes.With a ratio of iron to aluminium of 1 1 for example the “aged” precipitate was a homogeneous solid solution whereas a precipitate filtered immediately contained both a solid solution phase (of higher iron content than the “aged” precipitate) and some free aluminium com-plex. With this ratio it appears that the equilibrium condition of the solid solution is not reached instantaneously on precipitation ; it is possible that some adsorption of aluminium One further aspect of the nature of co-precipitated oxinates may be noted 406 CHIRNSIDE PRITCHARD AND ROOKSBY OXINE PRECIPITATES oxinate on the iron-rich co-precipitate may take place when comparatively high con-centrations of aluminium are involved.The mechanism of co-precipitation however is most easily envisaged in terms of the solid solution effects revealed by the X-ray examina-tion. Considering zinc and magnesium it is likely that so far as the oxine radical is concerned little differentiation is made between zinc and magnesium ions in solution in the range of $H values in which both are precipitated. In the mixed oxinate pre-cipitate zinc and magnesium atoms occupy similar sites on the space lattice and are randomly distributed over these positions. It is not surprising therefore that when the lower pH limit for magnesium precipitation is reached there is still a tendency for mag-nesium atoms to be retained by the main zinc oxinate crystal lattice and that the $H has to be lowered considerably below this limit for this tendency to be obviated.From a practical point of view separation of either of the pairs of metals considered, under the conditions described may be effected only in very narrow pH ranges. There may of course be other methods of effecting separations; for example according to Berg, aluminium may be separated from iron with oxine if the metals are in malonic or salicylic acid solution but alternatives of this nature are not always available for other separations. It is hoped to investigate other instances of co-precipitation as opportunity permits. SuMMARY.-In the gravimetric determination of certain metals by the use of 8-hy-droxyquinoline accurate results may depend on the employment of the correct drying temperatures.The precipitates obtained with 8-hydroxyquinoline from solutions containing mag-nesium zinc iron and aluminium respectively were dried at various temperatures and the changes in weight at 98" C. 110" C. 140" C. and 160" C. were observed. The compositions were further investigated by the X-ray diffraction method some account of which is given. The anhydrous form of the iron and aluminium complexes is readily obtained at 98" C., but dihydrates of the zinc and magnesium oxine complexes are formed. The dihydrate of the zinc complex is substantially decomposed at 110" C. but that of magnesium is not completely dehydrated below 160" C.It is recommended that in gravimetric deter-minations the zinc and magnesium precipitates should be dried at 160" C. The mechanism of the co-precipitation of magnesium with zinc and of aluminium with iron was also investigated. Moyer and Remington's work was repeated but no evidence of adsorption was obtained. X-ray examination shows that co-precipitation can be attributed to the formation of solid solutions of the magnesium and zinc and of the iron and aluminium complexes. Under the conditions of the experiments the separation of magnesium from zinc and of iron from aluminium is possible only over a very narrow range of PH. REFERENCES 1. 2. 3. 4. 5. 6. 7. 8. - J . Sci. Inst. 1941 18 84. 9. R. Berg "Die Analytische Verwcndung von o-Oxychinolin und seiner Derivate." F .L. Hahn and K. Vieweg 2. anal. Chem. 1927,71 122. H. R. Fleck and A. M. Ward ANALYST 1933 58 388. R. C. Chirnside J . SOC. Glass. Tech. 1935. 19 279. H. B. Knowles J . Res. Nat. Bur. Stds. 1935 15 88. H. V. Moyer and W. J. Remington J . Ind. Eng. Chem. Anal. Ed. 1938 10 212. H. P. Rooksby J . Roy. Soc. Arts 1940 88 308. H. Gotd J . Chem. SOC. Japan 1933 54 725. May 1941 DISCUSSION Mr. P. BILHAM said that when attempting to determine copper by means of 8-hydroxyquinoline he, too had met with difficulties due to contamination of the precipitate by other metals. He had overcome these difficulties by destroying the oxine precipitate in the wet way with nitric and sulphuric acids and determining the copper by another method.Referring to the X-ray examination he was interested to see that when the zinc oxine complex was dried as the temperature was raised a crystalline substance was obtained a t 98" C. which changed into an amorphous form and finally reverted into the crystalline form The aluminium precipitate however passed from the crystalline form at 98" C. into an amorphous form which persisted a t 160" C. If the temperature were raised above 160" C. would a crystalline form ultimately be obtained? He understood Mr. Rooksby to say that the dimensions of the unit cell were settled practically by the dimensions of the organic part of the molecule and that only small changes were caused by the substitution of one metal atom by another. Was the pattern they saw given by diffraction from the organic atoms or the metal atoms COMMON THE BUFFER CURVES OF SILAGE EXTRACTS 407 Mr.€3. R. FLECK called attention to the co-precipitation of oxine with metal oxinates. Dr. Ward and he had overcome co-precipitation difficulties particularly with magnesium by using other methods of separation e.g. by using ammonium tartrate instead of ammonium acetate for a buffer solution. Magnesium and zinc were possibly the worst pair of metals on which to work. Mr. CHIRNSIDE replying to Mr. Bilham said that he could well understand that some difficulty had been experienced in determining copper as oxinate. Replying to Mr. Fleck he said that they had not overlooked the possibility of effecting separations by other methods such as in ammonium and sodium tartrate solutions. It was hoped to explore these more fully. The choice of metals used in the experiments had been governed largely by the earlier work of Moyer and Remington. Mr. Fleck’s remarks on the co-precipitation of oxine with metal oxinates were interesting. Actually reference was made in the paper to the volatilisation of “free” oxine during the drying process. Mr. ROOKSBY said that the particular complexes to which Mr. Bilham referred were those of zinc and magnesium. The zinc complex whether dried a t 140” or 160” C. had the same composition. It passed from the amorphous to the crystalline condition a t 160” C. partial crystallisation appearing t o take place a t 140” C . The question of crystallising the anhydrous amorphous magnesium complex had not been investigated but it was possible that one could promote crystallisation by suitable heat treatment. With regard to Mr. Bilham’s final question the lines on the powder photographs should be looked upon as arising simply from planes of atoms; the determination of the kind of atom in any given plane was in general of considerable complexity. This was what the X-ray patterns indicated

ISSN:0003-2654    

DOI:10.1039/AN9416600399

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

COMMON THE BUFFER CURVES OF SILAGE EXTRACTS 407 The Buffer Curves of Silage Extracts BY R. H. COMMON PH.D. A.I.C. WATSON and Fergusonl demonstrated general relations between the pH of silage and the proportions of volatile and non-volatile organic acids and of amino acids and volatile bases, and pointed out that a $H determination affords one of the best criteria of silage quality. It will be shown that there are theoretical and experimental grounds for employing buffer curves of silage extracts to secure a rapid approximation to the ratio of volatile acids to non-volatile organic acids other than amino acids in the extracts. Lactic acetic and butyric acids are the most important of these acids in aqueous extracts of silage. The PK1 values for lactic acetic and butyric acids are 3-85 4-73 and 4.8 respec-tively (Clarke).2 The buffering capacity of silage extracts between about pH 3 and j5H 5 is therefore mainly due to these acids and their salts for the buffer index of the phosphate system is low over this range and buffering due to the amino acids probably only becomes significant below fiH 3-5 to 3.0.Moreover the PK1 values of acetic and butyric acids, i.e. of the chief volatile acids are fortunately very close together and propionic acid ($K1 = 4.8) will buffer in the same range as butyric acid. Silages of good quality are relatively rich in lactic acid and poor in acetic acid and contain little or no butyric acid silages of poorer quality are relatively poor in lactic acid and rich in acetic acid and very poor “sour” silages contain little lactic acid much acetic acid and more or less butyric acid.The buffer index curves of silage extracts of good quality ought therefore to display maxima towards the region of PH 3-85 and extracts of poor quality ought to display maxima towards the region of pH 4.7 to 4.8. Thus the buffer index curves of such extracts may provide a rapid means of examining the organic acid content of such extracts and may be more satisfactory in individual instances tha 408 COMMON THE BUFFER CURVES O F SILAGE EXTRACTS estimates based on empirical relations between average values of pH and of proportions of volatile and non-volatile organic acids. In preliminary experiments to test the possibilities of such methods extracts of grass silage and various solutions of lactic acetic and butyric acids were used.All silage extracts were prepared by shaking 200 g. of finely chaffed silage with 400 ml. of C0,-free distilled water for 3 or 4 hours squeezing out as much extract as possible through a muslin cloth and clearing on the centrifuge. The colloidal matter left in the extract especially with poorer silages of high fiH is hardly likely to affect the buffering power over the buffer range of lactic acetic and butyric acids as compared with the effect of the acids themselves. TITRATION CURVES.-POrtiOnS of the solution or extract (25 ml.) were titrated with N / 2 sodium hydroxide solution or hydrochloric acid the fiH was determined by means of a glass electrode and calomel half-cell after each addition of 0.5 ml. of base or acid and the titration curves were plotted.Buffer index curves (18 curves) were derived from these titration curves by applying the Van Slyke3 formula as described by Small? PH shift x vol. of buffer solution in litres dB d 9 H - m -AB - g equiv. conc. base (or acid) x vol. of base (or acid) in litres p = - -For pH shifts of 0-5 unit when N/2 acid and base are used and 25-ml. portions of the buffering solution are taken this equation becomes : 0.5 x ml. of N/2 acid (or base) /3= 0.5 x 25 ml. Woodman's5 procedure was used for the chemical determinations of total acidity, volatile acidity (1000 ml. of distillate) amino acids and volatile bases. All results were expressed in terms of ml. of N/10 solution per 100 g. of fresh silage. The difference between total acidity (total alcohol value) and volatile acidity gave the non-volatile acidity.The difference between non-volatile acidity and the amino acids (i.e. regenerated alkali) gave the residual acidity which is frequently adopted as a measure of the lactic acid in silage extracts. A number of /3 curves were constructed for silage extracts as well as for solutions made up with acetic lactic and butyric acids to imitate silage extracts in respect of organic acid content. Preliminary experiments confirmed the view that silage extracts of good quality display maximal /3 values towards fiH 3-85 and that the maximal values with silages of poor quality tend to be in the region of fiH 4.7 to 4.8. The /I curves of silage extracts of high amino acid content were inclined to be higher in the region of PH 3 than were the curves of imitation extracts containing mixtures of lactic and acetic acids.Apart from this there was a reasonable agreement between the buffer curves for the silage extracts over the range pH 3 to @H 6 and the curves for mixtures made up to imitate the extracts in respect of organic acids in accordance with the results of chemical determinations of the volatile and non-volatile acids other than amino acids present in the actual silage extract. Although these preliminary experiments indicated that buffer index curves of silage extracts could be used qualitatively in forming a general idea of the amount and nature of the organic acids present it was clear that some means of deriving suitable quantitative expressions from the curves was necessary.QUANTITATIVE ExPREssIoNs.-After several methods of treating the curves had been tried the following simple considerations afforded a satisfactory approach to the problem. The moment of the area of the p curve of a mixture of acetic and lactic acids about the p axis is dependent on the ratio of the two acids. For the area of the curve included between @Hl and PH this moment is given by the expression But this expression is the same as The right-hand term of this equation is the area included between the titration curve and the B axis for the range @Hl to pH, and the moment of the fi curve about the /3 axis may be obtained directly from the titration curves without constructing the /3 curve COMMON T H E BUFFER CURVES OF SILAGE EXTRACTS 409 The area may be measured by numerical integration or more conveniently with a plani-meter.The centre of gravity of the curve is readily derived by dividing the moment by the amount of base + acid required to shift the PH of the solution or extract from pH to pH, for Inspection of a number of actual titration and /3 curves for silage extracts suggested that it would be advisable to test the integration over a wider #H range than 3-85 to 4.73, since this would give a wider range of $H values for the centres of gravity and also include a larger number of PH readings. It was thought advisable not to integrate the curves outside the range #H 3.5 to 5.5 in order to avoid the possible influence of amino-acid buffering below pH 3.5 and the steep portion of the titration curves beyond @H 5.5.4.20 4.30 4.40 4.50 4.60 PHCG Fig. 1. This procedure was next applied to a series of 60 routine analyses of grass silage. These silages had practically all been prepared with the addition of molasses. The data were not selected except that samples of sweet dark brown silage of high dry-matter content were not included. The areas included on the acid-base axis for the range $H 3.5 to $H 5.5 were read and divided by the amount of acid + base required to bring about this pH shift. The resulting values for the centres of gravity of the ,B curves, which are in terms of j5H and may be designated ~ H c G were then plotted against the volatile acidity (VA) of the extracts expressed as a percentage of the volatile acidity + residual acidity (VA 4- RA). The full data are presented in Fig.1. The values - . loo plotted against pH of extract are shown in Fig. 2. (VA + RA) of loo with P H c G is 0.8960 while the co-efficient The coefficient of correlation of of correlation with pH of extract is 0.7489 These correlations are significantly different (P being little more than 0.01) so that ~ H C G is definitely more closely correlated with VA VA + RA VA + RA loo than is j5H of extract 410 COMMON THE BUFFER CURVES OF SILAGE EXTRACTS The regression equation for estimates of - loo from PHCG is VA + RA loo - 238.4 PHCG - 995.0 VA + RA -The line to this equation has been inserted in Fig. 1. loo from p~ of extract is VA + RA The corresponding equation for estimates of IrA VA+RA- loo - 38.30pH - 119.93 VA VA + RA loo from $HCG is 2.51 and from pH of The standard error of estimates of extract it is 6-07 showing the much greater accuracy of estimates from ~ H c G .I 4.0 4'5 50 5 5 69 PH Fig. 2. Watson has proposed to regard silages having Non-volatile acids calc. as lactic acid Volatile acids calc. as acetic acid Converting this ratio into terms of equivalents the limiting value o€ ( 1 as unsatisfactory. the ratio becomes 0.67 instead of 1 corresponding to a value of x 100 = 60 per cent and ~ H C G = 4.43 approx. VA + RA Silages with a value of ~ H C G > 4.43 therefore fall into the less unsatisfactory class. The correlation between PHCG and the ratio VA/(VA + RA) as determined by Woodman's method is significantly closer than that between pH and this ratio.One reason for this closer correlation appears when pH is plotted against PHCG (Fig. 3). It can be seen that the correlation is good so long as the ;bH of the extract lies below about 5.0; above that value the scatter of the dots increases possibly owing to the partial neutralisation of the organic acids by products of protein breakdown. The advantage of the ~ H C G determination over a simple ;bH on the extract is that it rules amino acid volatile base are required the rather lengthy steam distillation of the volatile acids out this interference at high PH values. and total acid Moreover when only the ratios volatile aci COMMON THE BUFFER CURVES OF SILAGE EXTRACTS 41 I may not be necessary. The extract (7-5ml.) may be diluted with 70 ml. of alcohol, titrated with N/2 sodium hydroxide solution from a micro burette (phenolphthalein as indicator) the volatile bases distilled off into standard acid the residual acidity titrated to give amino acids.and the amounts of volatile and residual aciditv calculated from v volatile acidity J the ratio as determined from the titration curve. It volatile aciditv + residual aciditv’ may be mentioned thatdthe regression 1ineJdrawn in Fig. 1 passes fairly close to the values for 100 per cent. acetic ( ~ H c G = 4-614) and 100 per cent. lactic acid ( ~ H c G = 4.184). The divergence may be due to at least two factors (1) the presence of other acids ( e g . succinic) in the extracts in amounts sufficient to affect the shape of the /3 curves; (2) the inaccuracies and errors involved in the Woodman process such as those due to partial volatility of lactic acid in steam (Smith6).4.6 C 450 ~ H C G 44c 4.3c 4 20 I 4 . 0 4.5 5 9 5.5 6.0 PH Fig. 3. How far the considerations outlined in the present paper are applicable to acid-treated silages such as A.I.V. fodder is a matter for further investigation. The data dealt with above do not include any figures for sweet dark brown silage produced by “warm” fer-VA x 100 lies VA + RA mentation. between 40 and 50 per cent. ; silages of this type are therefore satisfactory in these respects. They have however a high dry-matter content (frequently over 30 per cent.) a low crude protein content and a very low carotene content. While such silage is easy to recognise organoleptically it is unsatisfactory that no direct chemical means of characterising it appears to be available.It is noteworthy that low fiH does not by itself necessarily mean a high carotene content and that very sour butyric silage with high pH may contain large amounts of carotene. A crude carotene content of 64 mg. per 100 g. of dry matter has been noted in a sour butyric silage of @H 6.0 made from very young Italian rye grass; the carotene was estimated by Moon’s’ method. Occasionally silage of very poor quality with fiH greater than 5.0 and very low content of organic acids is encountered. Silage of this type is usually easy to detect by subjective means but a buffer curve for the extract provides rapid confirmatory evidence. A fiH determination by itself is not a sufficient criterion however for silage with fiH greater than 5.0 frequently has a high organic acid content and correspondingly high buffering capacity as well as being of good feeding value in practice.Finally it is possible that refinement of the buffer index curve method may be of use in research. For example in one instance the curve suggested the presence of a little Such silage usually has a @H between 4.0 and 4-5 an 412 OSBORN THE DETERMINATION OF ZINC IN MAGNESIUM -4LLOYS succinic acid; a subsequent rough separation (Russell8) yielded a small amount of an organic acid the ammonium salt of which gave a pyrrol reaction far too strong to have been due to the minute amounts of chlorophyll left in the acid thus confirming the presence of succinic acid. SUMMARY.-(~) It is suggested that the buffering capacity of silage extracts in the region pH 3.8 to pH 4.8 is mainly determined by the ratio of lactic to acetic and butyric acids and that the buffer curves of such extracts may be more useful in the routine examina-tion of silage than single pH determinations.x 100 and the pH volatile acidity volatile aciditv + residual aciditv (2) A relationship between corresponding to the centre of gravity of theJbuffer index curv; between pH 3.5 and PH 5.5 has been calculated for 60 samples of molassed and ordinary grassland silage. It is suggested that such relationships based on potentiometric titrations may be useful in rapid routine examinations of silage and that the pH corresponding to the centre of gravity of the buffer index curve may be a more sensitive index of silage quality than a single $H deter-mination. I am indebted to Mr. R. W. Hale of this University for undertaking the statistical treatment of the data to Professor W. McCrea for guidance in devising a suitable approach to the mathematical treatment of the titration curves and to Mr. R. J. Cummings of this Department for carrying out the numerous 9H measurements. REFERENCES 1. 2. W. M. Clarke, 3. 4. 5. 6. A. M. Smith ANALYST 1938 63 777. 7. 8. E. J. Russell id. 1907-08 2 292. S. J. Watson a;d W. S. Ferguson J. Agric. Sci. 1937 27 1. D. D. Van Slyke J. Biol. Chem. 1922 52 525. J. Small “Hydvogen-ion Concentration in Plant Cells and Tissues,” 1929. H. E. Woodman J. Agric. Sci. 1925 15 345. F. E. Moon J. Agric. Sci. 1939 29 295. The Determination of Hydrogen Ions,” 3rd Ed. 1928. AGRICULTURAL CHEMISTRY DEPARTMENT THE QUEEN’S UNIVERSITY OF BELFAST AND CHEMICAL RESEARCH DIVISION OF THE MINISTRY OF AGRICULTURE FOR NORTHERN IRELAND May 194

ISSN:0003-2654    

DOI:10.1039/AN9416600407

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600412

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600414

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600415

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600416

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600417

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600418

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate.There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international.The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr. Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively.Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies. Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited.The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation.Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE.By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time.The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents. It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600419

出版商:RSC    

年代:1941

数据来源: RSC

摘要:

426 REVIEWS INKS : THEIR COMPOSITION AND MANUFACTURE. By C. AINSWORTH MITCHELL, D.Sc., F.I.C. Fourth Edition. Pp. xi + 408. London: Charles Grihn tt Co., Ltd. 1937. Price 12s. 6d. net. This, the fourth edition of the standard and, indeed, so far as the reviewer’s knowledge goes, the only text-book on the subject in the language, bridges L gap of 13 years. The author, pre-eminent in his particular sphere, needs little more introduction to the world of technical industry than he does in his official capicity to readers of THE ANALYST, while his reputation in forensic science in all that appertains to handwriting is international. The chemistry of ink, difficult as it is and at times not a little obscure, hcl- riot developed markedly in the interval since 1924; but what progress has been made is covered by Dr.Mitchell in this edition in a very thorough manner. He has found it necessary to enlarge his work to the extent of some 20 per cent. and, in addition, to rewrite a large portion. The arrangement of the book follows the lines of previous editions. After a comprehensive historical introduction, the work is divided into three sections dealing with writing inks, printing inks, and inks for miscellaneous purposes, respectively. Under Section 1 are considered the chemical nature and treatment of the various raw materials used for writing inks from lcmp black to galls, the composition of finished iron-gall, logwood, vanadium, aniline black, and coloured inks, as well as a comprehensive scheme €or the tech~ical examination of inks, handwriting specimens and the identification of forge:-ies.Section 2 deals with the manufacture and examination of printing inks. ,tnd Section 3 with the miscellaneous materials entering into the compositilxx of copying, marking, safety, sympathetic, typewriter inks and so on. Amongst new matter may be noted references to the use of lignone sulphni--,ites in connection with writing ink, a scheme for the identification of individual con- stituents in inks in the form of writing, and the application of filtered ultra-.& if )let light and of infra-red photography in the elucidation of those problems to which such methods are suited. The British Government Standard Specificatior:s for Writing Inks, revised in 1928, are included for the first time. The avaihble evidence upon the constitution of gallotannin is brought up to date and <tbly reviewed, and there is a Comprehensive list of British patents.It is as difficult to withhold admiration of the encyclopaedic scope cjf the matter and references in this book as it is of the erudition and industry displiiyed in its compilation. Practically nothing that comes to mind has escaped atterition, and it is with rather impish glee that the reviewer, after careful search, asserts that he finds no specific reference to the type of alkaline (ammoniacal) gallotannate- iron ink, said t o find favour in the United States, although the di-ammonium hydroxyferrigallate compound of Silbermann and Ozorovitz receives notice. Nor is there mention of that class of quick-drying writing fluids which depend for their efficiency upon partial destruction of the paper sizing by caustic alk 1.5 or sodium silicate. There is no evidence that lignone sulphonate inks have proved se-rious competitors to iron-gall writing inks (pp. 15 and 175). Apart from the unkttmwn quantity of permanence, the principal failing of this type lies in their liability to contain traces of free sulphurous acid to which suspicion attaches in connt-ction

ISSN:0003-2654    

DOI:10.1039/AN9416600421

出版商:RSC    

年代:1941

数据来源: RSC