摘要:

“.HE ANALYST. DECEMBER, 1893. THE LATE ROBERT HIGGINS DAVIES, F.I.C., F.C.S. IT is with the deepest regret that we have to record the death, at the early age of forty-two, of our esteemed colleague, Mr. R. H. Davies, one of the Secretaries to the Society of Public Analysts. He passed away, after a long illness, at Bournemouth, on November 16. Mr. Davies was a native of Newport, Monmouthshire, and received his early education at Wesley College, Taunton, subsequently being articled as pupil to the late Mr. Edwards, of Dartford, Kent. He obtained, in 1871, the first of the three Junior Bell Scholarships, and became a student at the School of the Pharmaceutical Society, where his career was a disbinguished one, for during this period he took, in 1872, silver medals (the highest award then given) in chemistry, botany, and materia medica, and a bronze medal for practical chemistry.On leaving the Pharmaceutical Society’s School, he received an appointment froin a leading firm in Dublin; this he held for a, year, after which he became demonstrator in the laboratories of the Pharmaceutical Society. He also occupied for some time the position of private assistant to Dr. Attfield. Shortly afterwards he was chosen as Assistant Secretary to the Pharma- ceutical Conference. He resigned his position as demonstrator on being appointed Public Analyst for Hammersmith, and afterwards was elected to the important office of Chemist and General Superintendent of the Drug Department of the Society of Apothecaries. I n 1889 he was appointed a member of the Board of Examiners of the Pharmaceutical Society.These appointments he held up to his decease. He also served for three years on the council of the Institute of Chemistry. As Mr. Davies’ work lay principally in the direction of pharmacy, his papers, of which the foliowing is a iisf, appeared in the Journal of the Pharmaceutical Society : 6 ‘ Use of Potassium Ferro- and Ferri-cyanides for the Detection of Cobalt and Nickel,” 1876 ; ‘( Constituents of the Ivy,” 1876 and 1877 ; ‘: Notes on Sulphate of Quinine,” Notes on Three New Chinese Fixed Oils,” 1885 ; ‘‘ The Iodine Absorptions of the Essential Oils,” 1889. Besides these, the following joint papers appeared : ‘‘ On the Composition of Easton’s Syrup,” by Davies and Schmidt, in 1883 ; ‘ l Notes on Euca- lyptus Oils,” by Davies and Pearmain, in 1891 ; and (‘ Notes on Eucalyptol,” by the same authors, in 1892. Mr. Davies became a member of the Society of Public Analysts in 1887, was elected a member of council in 1889, and appointed one of its secretaries in 1891. He has also been a member of the Publication Committee of THE ANALYST since the Journal became t’he property of the Society. Many of his other papers have not been published.286 THE ANALYST. In Mr. Davies the Society loses a valued member, one whose courteous and affable disposition had endeared him to the hearts of all his fellow members, whilst his sound and practical judgment gave considerable weight to his expressed opinions. His loss will be deeply felt by a wide circle of friends both in and outside the Society. He leaves widow and two sons.

ISSN:0003-2654    

DOI:10.1039/AN8931800285

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

286 THE ANALYST. NOTE ON AN ABNORMAL MELTING-POINT. BY E. J. BEVAN, F.I.C. I n the course of an examination of a crystalline fatty body obtained from pure lard by fractional crystallization from ether, I had occasion to determine its melting- point. For this purpose capillary tubes were filled with the melted body in the usual way. The melting-point, determined within a few minutes of filling the tube, was 47" C. Another tube, filled at the same time, but examined the next day, gave a, melting-point of 61.5". This tube, after allowing the body to solidify, was plunged into water at 50", and, to my great surprise, was found to melt instantly to a per- fectly clear fluid. The experiment was repeated at intervals down to a temperature of 45.5', at which point it remained solid.A number of experiments were made on a larger scale, using test-tubes internally coated. After standing twenty-four hours, the substance remained solid, wheii the tube was plznged into water at 50"; One half of the contents of the tube was then melted over a burner and allowed tosolidify. On plunging the tube into water a t 50" it was found that the portion recently heated melted to a clear liquid, the remainder being quite solid and opaque ; and the portion melted corresponded exactly with the part of the tube heated. It is clear, therefore, that the body has two very definite and widely different melting-points, and that it passes slowly and spontaneously from the state of low melting-point to that of the higher, and can be made to pass from the high to the lower state immediately by simple heating.As I hope to show you, it can also be made to pass from the lower to the higher st ate by gradually increasing the temperature. Thus, I take a tube recently heated and place it in water at about 43". At thisTEE ANALYST. 287 temperature it remains solid; on gradually raising the temperature, I find that the substance melts to a clear liquid at about 47". If now the temperature be still further gradually increased, the substance passes again into the solid state at about 5 3 O , and does not melt again till a temperature of about 62" is reached. The existence of the two melting-points was confirmed by the use of Cross and Bevan's method, as described in the Chem. Xoc. Journal for 1882. These experiments emphasize the importance, which has before been insisted on, of delaying the determination of melting-points for some hourEt after the substance has been melted. It has since been pointed out to me by Mr. Allen that some curious experiments by Mr. T. Maltby Clague on the alteration of the melting-point of cocoa-butter, are recorded on p. 570 of his Commercial Organic Analysis, vol. iii., part ii. The Chairman (Mr. Otto Hehner) remarked that the subject was very im- portant. Analysts often met with such difficulties in analyzing fatty substances. I t would be very desirable to come to some agreement as to the conditions under which the melting-point of a fat ought to be taken. In the absence of Mr. Stokes, the Secretary (Dr. Dyer) ready the following paper :

ISSN:0003-2654    

DOI:10.1039/AN8931800286

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

TEE ANALYST. 287 ON THE FORM OF CERTIFICATES ON ADULTERATED SAMPLES. BY A. W. STOKES, F.I.C. Finding a sample of milk submitted to me by St. Luke’sVestry to be deprived of ( ( 1 am of opinion that the said sample contained the parts as under, ‘L Twenty-five per cent. less than the normal proportion of cream, Observations. (( No change had taken place in the constitution of the sample that would The Magistrate ruled that as I did not give the component parts of the milk, the certificate was invalid. The Vestry laid the facts before the Local Government Board. They replied as follows : 25 per cent. of its cream, I certified to this in the following way on the legal form : or the percentages of* ingredients as under : interfere with the analysis. ” “ Local Government Board, ‘L \Vhitehsll, S.W., “ 10th October, 1893.6; SIR,-I am directed by the Local Government Board to state that they have had under consideration your letter of the 22nd ultimo in reference to a difficulty which has arisen respecting an analyst’s certificate under the Sale of Food and Drugs Act, 1875, as to a sample of milk. The Board have also had before them a copy of the certificate referred to, which was enclosed in your letter of the 27th ultimo. (‘ I am now to state that it appears to the Board that the difficulty has arisen, not from the provisions of the Act, but from the particular form of words adopted by the analyst in the case in question. They consider that in the form of certificate * The word c L foreign ” in thg certificate standing before “ ingredients ” was cancelled in ink.288 THE ANALYST.prescribed by the Act the analyst is required either to state ‘ the parts ’ contained in the sample or ‘ the percentage of foreign ingredients,’ but that there is no obliga- tion on him to state both the parts and the foreign ingredients, one requirement being alternative to the other. They do not understand, therefore, why in the case in question the analyst should not have stated in his certificate that the sample con- tained ‘ the parts as under,’ viz., so many parts of fat, so many parts of water. Having done this, his proper course would apparently have been to enter, under the heading ‘Observations’ in the prescribed form, that he was of opinion that this statement of ‘parts’ showed that abstraction of a portion of the milk (i.e., 25 per cent.of its cream) had taken place. “ The Board agree in the view that the certificate as it stands is invalid, since it neither gives the ‘ parts ’ nor the ‘ percentages of foreign ingredients.’ “C. N. DALTON, I am, sir, your obedient servant, L( Assistant Secretary. “G. W. PRESTON, Esq., “ Clerk to the Vestry of the “ Parish of St. Luke, Middlesex.” I cannot see that the view taken by the Local Government Board can possibly comply with the Act, A reference to the schedule of the Sale of Food and Drugs Act, 1875, shows that under the word ( ( Observations” directions are given thus : “Here the analyst may insert at his discretion his opinion as to whether the mixture (if any) was for the purpose of rendering the article portable or palatable, or of preserving it or of improving the appearance, or was unavoidable, and may state whether in excess of what is ordinary, or otherwise, and whether the ingredients or inaterials mixed are or are not injurious to health.I n the case of a certificate regarding milk, butter, or any article liable to decomposition, the analyst shall specially report whether any change had taken place in the constitution of the article that would interfere with the analysis.” Observations ” column seem quite to preclude placing there the amount of the adulteration. It seemed to me that in placing the words “ 25 per cent. less than the normal proportion of cream ” where I did, I was stating ‘( the parts as under,” so far as the adulteration was concerned. I thought that the adulteration form was intended to show the extent of the adultera- tion of the sample, and not to give the full component parts of the sample.Other- wise the ‘‘ genuine ” form might equally have filled into it the component parts of the article. Knowing the interest of the subject to so many members of the Society, 1 venture to trouble you with this note, so that those concerned may see the view taken by some authorities on the subject, and may act accordingly. These precise directions as to the use of the * DISCUSSION. Dr. Bernard Dyer said that the Local Government Board had informed Mr. Stokes in their communication that his certificate was irregular, inasmuch as he had not stated “ parts.” He (Dr. Dyer) thought it was impossible to state parts which were not there.Mr. Stokes’s proper course would have been to say that the sample contained 100 parts of skimmed milk, and, in his observations, to state the extent of the skimming. Mr. Hehner thought that the correspondence had convinced the members whoTHE ANALYST. 289 were present that quibbling was not confined strictly to the members of the legal profession; but, in view of the possibility of a very long discussion on the subject- in which every public analyst took some interest-he trusted that members would contribute towards the enlightenment of Mr. Stokes, and not protract the proceedings at the expense of the vinegar question. Mr. Alfred H. Allen said that the magistrates acting in one of his districts, at the suggestion of the solicitor for the defence, had held that the whole of the analysis of a, milk ought to be given.On another occasion the same Bench held that, where soda-water containing lead was in question, he ought to give the percentage of lead, not the grains per gallon or per 100,000, and the full analysis of the water containing it. In the case of milk, he was in the habit of stating, ‘‘ The sample contains the parts as under: milk 88, added water 12 per cent., total 100 ” ; and he could not see how, if the prosecution was properly conducted, the defendant’s solicitor could get over that. I n the case of skimmed milk, he thought analysts were bound to give the constituents, if from the results of the analysis an opinion was formed that the sample had been skimmed, or-was deficient in fat. It might happen in the future that a, method of analyzing milk would be devised which was entirely independent of a determination of total solids, direct or indirect ; and if that should happen, was an analyst to be compelled to give analytical data which he did not require for the purpose of forming his own opinion on the sample? In the case of butter, coffee, and other articles, the contention that the analytical data should be given was still more preposterous, as only an expert could interpret them.Mr. Cassal remarked that he had read a paper before the Society in which he had dealt with the point raised by Mr. Stokes. He should be glad if the Local Government Board could see their way to give public analysts a little more active support, and would give some further consideration to the difficulties by which public analysts were beset.Objection might certainly be taken to the form of this certificate, because it neither gave ‘‘ percentage of foreign ingredients ” nor ’‘ parts as under” ; but while these words were suggested in the schedule, they were not compulsory under the Act. He (Mr. Cassal) had had occa- sion to point out to the Society that it was perfectly possible, in the case of fat abstraction from milk, to give ‘‘ parts as under.” When this was done, the certificate was strict1.y in accordance with the terms of the schedule. In this case there was 25 per cerit. of fat abstracted. Nr. Stekes had certified that there tvas (‘25 per cent. less than the normal proportion of cream,” a form of statement which was not one which he (Mr.Cassal) thought desirable, and which could hardly be regarded as accurate, since cream was not fat ; but it was perfectly possible to conform with the suggestions of the schedule, and to use the words ‘‘ parts as under” by saying that ‘‘ the said sample contained the parts as under,” so many parts of milk of genuine composition, but of the poorest quality, and so many parts of milk devoid of fat. It could not be said that that was not the composition of the article, Where there was no added water, the percentage of fat abstracted was obviously the same figure as the percentage of milk devoid of fat. This form of certificate gave the actual composition as determined by analysis of the sample submitted to the analyst, There could be no quibble raised upon that form of certificate, because it WRS strictly in He had just perused the letter.290 THE ANALYST.the form suggested by the schedule, utterly foolish as that form was, and because it showed the actual composition of the sample, which was all ths Court and the public required to know. The public had nothing to do with the data upon which an analyst formed his opinion. There was nothing in the Act which required a public analyst to state analytical details. He had thought that the members of the Society were pretty well agreed some time ago that it was most undesirable that public analysts should state analytical data in their certificates. He (Mr. Cassal) sincerely hoped that the Society would adhere to this position, and that, as far as possible, all analytical data would be kept out of reports, certificates and legal cases.Mr. E. J. Bevan suggested that the discussion be postponed to the next meeting. It was a matter which very closely affected public analysts, especially those in the neighbourhood of London. He could mention one or two curious and interesting circumstances in connection with the wording of certificates, and no doubt other public analysts would like to do the same. Dr. W. Morgan wished to know if he was to understand that Mr, Cassal main- tained that no percentages should be given in certificates. He believed analysts were bound to give the ‘‘ parts as under,” or the percentages of foreign ingredients. His practice, in the case of skimmed milk, was to say that 100 parts of the sample con- tained so much genuine whole milk and so much skimmed milk.He had had a peculiar case in which he certified the presence of an aniline dye in jam, but it was dismissed because he had not given the percentages, Mr. Cassal observed that Dr. Morgan did not differ from him to any appreciable extent. Dr. Morgan was really advocating practically the form of certificate which he (Mr. Cassal) had previously mentioned that evening, where, under the words “ parts as under,” so many parts of milk of genuine composition and so many parts of milk devoid of fat were stated. If Dr. Morgan considered that the skimmed milk he referred to was devoid of fat, he (Mr. Cassal) inferred that there was no difference between their views. Mr. Bevan argued that, as the schedule stated that the 1‘ parte as under,” or words “ to the like effect,” were to be given, clearly the words to the like effect ” embraced the case mentioned by Mr.Stokes, Mr. Haden Corser had objected to his (Mr. Bevan’s) certificates, which were usually in this form : “1 am of opinion that the sample contains 10 per cent. of added water ” ; and, at the solicitation of the Clerk to the Board, the certificate was altered thus: ((1 am of opinion that the sample contains, milk 90 per cent., added water 10 per cent.” As the Act allowed analysts to use words “ t o the like effect,” this was clearly an allowable form of certificate. Moreover, the schedule of the Act stated that the percentages of foreign ingredients might be given. If this were done, he thought that, on the other hand, a simple statement of the percentage of the ingredients taken out should be suflicient. Mr.Hehner considered that it was very unadvisable to give a, certificate which did not strictly and literally comply with the schedules given in the Act when such a certificate could easily have been given, and, although the Local GovernmentTHE ANALYST. 291 Board’s letter was not clearly worded, still, it contained a fair, if not a sufficiently explicit, suggestion. He thought there could not be much difficulty at the present time, especially for an analyst as experienced in the working of the Sale of Food and Drugs Act, as Mr. Stokes undoubtedly was, to word certificates so that they abso- lutely complied with the Act. Mr. Stokes seemed to be in dread of the opinion of some individuals, particularly solicitors, or possibly magistrates.It never entered into his-Mr. Hehner’s-mind to trouble himself about what a magistrate or a solicitor might think, provided he complied with the Act. Nothing could prevent a bench of magistrates from dismissing a case, however accurate the certificate might be. He had for some time past made it a rule to omit in every case giving in his certificates any semblance of an analytical figure, but to state what were the “ parts as under ”; and he had never found that there had been any serious difficulty. He had often been asked to supply analytical figures, but, whilst he was perfectly willing to give them in a letter, he would not do so in a certificate. Analytical figures were absolutely unintelligible to anybody but an analyst.A public analyst obtained his figures, not for the information of other people, but for his own use-to guide him in giving his opinion under the Act, or, in other words, to enable him to arrive at a correct opinion. The analytical figures were simply the means to satisfy himself, and to assist him in forming his opinion. I t seemed preposterous that a bench of persons not scientifically educated should be allowed to judge of analytical figures at all; and he also thought that an analyst should not show on his certificate the means that he used in order to enable him to give his opinion. If he were asked to give his reasons in court, then he would be bound to give them, and also his figures, and he would be glad enough to do so, because he would know more about the figures than anybody who might be in court could know. He was aware that the Act said “ words to the like effect,” but, unfortunately, the use of ‘( words to the like effect ” had led to the dismissal of cases. It would require a decision of the High Court to decide what were (‘ words to the like effect.” It was desirable that there should be such words in reference to such cases, for instance, as those of lead in soda-water, where the lead was expressed in grains per gallon ; or in that of alum in bread, where the alum was expressed as so many grains in a 4-lb. loaf. He hoped that members of the Society would adhere as strictly as possible to the schedule of the Act, whether they thought it unreasonable or not. It was best to comply with the suggested form. Analysts did comply with it when they gave the percentages of foreign ingredients in the case of adulterated artides ; and h e did net think that any chemists need trouble themselves about the matter, even if gentlemen like Mr. Ricketts asked for more. A long discussion on the vinegar question now followed, the report of which will appear in our next issue. (Conclusion of the Society’s proceedings.)

ISSN:0003-2654    

DOI:10.1039/AN8931800287

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

292 THE ANALYST. NEW FORM OF APPARATUS FOR HEATING THE WATER IN CENTRIFUGAL MILK - TESTERS. BY ROBERT H. WILKINSON. ALL who have used the Babcock milk-tester as at present constructed will have found a difficulty in keeping the machine at a proper temperature, and the clumsy method of adding hot water to the test-bottles, recommended by the makers of the machine, will not find favour in the eyes of any owner of a ( ( wash-bottle.” For the past two years I have had in constant use two 25-bottle-power machines, sometimes making as many as 200 estimations of fat per diem. Under these circum- stances the necessity of changing the water frequently was particularly tiresome. By a very simple contrivance I have overcome all the difhulties as regards hebting the water required for filling up the test-bottles, and also for heating the water in the tank of the machine.A glance at the accompanying sketch will show how this is accomplished. A hole is cut lower end, is fixed The tube A is in the bottom of the tank F, and a metal tube, A, closed at the to the tank. surrounded at the lower or outer end by a, metal shield, in shape like an inverted funnel, B, the stem of which, C, is continied above the highest part of the machine. poured into the tank F until tube A is filled, and the bottom of the tank covered to the depth of one-eighth of an inch. A wash-bottle, D, provided with a long flexible outlet tube with a glass jet and clip at the end, is clamped in position on the top of C. The burner E is now lit, and The mode of working is as follows : Cold waterTHE ANALYST.293 the tank F covered. The test-bottles are now filled with milk and acid, and fixed in their place in the machine, which by the time the bottles are ready is quite hot, and the water in G nearly boiling. After whirling, the bottles are readily filled with hot water by means of the syphon connected with the wash-bottle, the current being controlled by the clip H, I find a tube two inches by twelve quite large enough to heat a 25-bottle machine in twenty minutes when a Fletcher solid-flame burner is used. The smaller hand- machines would not require so large a burner or tube. The tube also, in machines where the driving-gear is at the side, could be conveniently fixed to the side of the tank F, and sufficiently high up to allow a burner to be placed under the lower end, as in Fig. 2. Double-jacketing the cover of the machine, as described in the October ANALYST, means inore trouble in changing the water in the jacket when it cools. Precisely the same effect can be produced by using a cover having a cup-shaped depression in the lid A for hot water, with a suitable removable cover, B, Fig. 3. Lansdowne Laboratory, Limerick.

ISSN:0003-2654    

DOI:10.1039/AN8931800292

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

THE ANALYST. 293 WATER ANALY SIS-THE INTERPRETATION OF RESULTS. BY F. WALLIS STODDART. (Reprinted from (( The Practitioner.”) THE question of the utility of chemical analysis as a means of determining the wholesomeness or the reverse of potable water has lately been raised in several quarters ; partly, no doubt, in consequence of outbreaks of enteric fever attributed with more or less reason to the use of water supplies not demonstrably polluted, but largely also as a result of the widely different opinions not unfrequently expressed as to the organic purity of one and the same water by different analysts. I n spite of all that has been written on the subject, no point in water analysis still remains so frequent a cause of this unfortunate variance of opinion as the mean- ing attributable to the presence of nitrates.This is largely due to the fact that water analysis is to a great extent in the hands of persons who have little or no opportunity of thoroughly examining the question for themselves, and who, therefore, are necessarily guided by the published opinions of leading sanitarians. Now, the text-book:which is, and has been for years, used exclusively by the vast majority of teachers of chemistry takes the extreme view that nitrates in potable waters are absolutely without sanitary signification ; the natural consequence being that there is a very large and annually increasing number of persons engaged more or less upon water analysis who, confessedly adopting this view without any modifi- cation, do not take the question of nitrates into consideration, and do not as a rule make any attempt to detect the presence of these salts.On the other hand, there are numerous practical workers at this subject whoTHE ANALYST. are convinced from long experience that the presence of nitrates in potable waters in proportions exceeding a certain minimum is a most important indication of pollution. Text-books which advocate this view are of course not wanting, but, for reasons into which it is not now necessary to go, they do not find a place in many educational establishments; whilst there are many treating more or less fully of water analysis which leave the reader practically in the dark. It is surprising that a more critical examination of this question has not been published, as conflicts of opinion are naturally not uncommon, especially where action is taken under the Public Health Act.Now, however, that an important Government Department, popularly looked upon as a court of appeal in similar matters, has taken a course entirely opposed to the experience of almost all practical sanitarians (ANALYST; xviii. 246), thereby raising a serious obstacle to a much-needed sanitary improvement, it appears to me, in view of the present invasion of this country by a terribly fatal disease, disseminated almost invariably by means of drinking water, that it is of the utmost importance that this question should, if possible, be settled once for all. It is in the hope of contributing towards this desirable consummation that I venture to place before those interested in the main- tenance of public health the following considerations, largely suggested by recent advances in our knowledge of the origin and mode of formation of nitrates (and nitrites) under the conditions naturally prevailing in the soil.That nitrates in natural waters are, to quote the most recent work, (( nearly exclusively derived from the decomposition of animal matters,” is pretty generally recognised ; though certain objections have been urged against this view, and will be discussed subsequently. It is contended, however, by one school of chemists that the presence of nitrates in whatever quantity, if unaccompanied by much unoxidized nitrogenous matter, is unobjectionable ; by a second, that water containing more than a certain minimal quantity should be condemned as dangerous to health, The latter class is further divided upon what may at first appear a merely theoretical point, namely, whether the danger attaching to the use of water of the character under discussion is of the same degree as that involved in drinking any sewage-polluted water, or is contingent upon the sewage matters, under slightly altered conditions, reaching the water in a less oxidized state.Those who hold the sanitarians who have been forced to take it both by a careful consideration of what is known of the causation of disease, and by the repeated observation of obviously polluted waters, which, though they yield insignificant quantities of unoxidized nitrogen, in some cases, at least, have been reasonably credited with communicating disease on evidence in all respects similar to that which is generally accepted as establishing the connection between sewage pollution and the dissemination of cholera and typhoid. I t may be of little consequence which view is adopted in advising a private client ; but in taking legal steps to close wells on public grounds in the face of opposition, it is most important to come to a clear understanding on this point ; and it will be well to bear this in mind whilst considering the broader question-Are we, or are we not, to ignore nitrates altogether 3 _ c _ _ ~ - _ _ 294 former :&w are prob&!~7 J COrnnDrati-ljr rWILwYI.V* few, bgt 8118, I believe, one I .E ~ prictica!THE ANALYST. 295 It will facilitate the discussion of this matter if we first formulate the arguments which have been advanced by those who deny any sanitary significance to the presence of nitrates in drinking water, and then consider each in detail.These arguments are as follows : I. Nitrates in themselves, and in the proportions in which they occur in natural waters, are harmless, 11. Nitrates may be present in appreciable quantities in pure waters, and may be absent from polluted ones. 111. Nitrification being essentially a process of oxidation, objectionable matters are l L burnt up.” IV. The completion of nitrification is a proof that the water has filtered through ti layer of soil of such thickness that it is necessarily deprived of harmful impurities. V. That there is a biological antagonism between the organisms effecting the various stages culminating in nitrification and those constituting the infective material, resulting in the destruction of the latter.I. Now, the first argument is so obviously beside the question that it would seem to be a waste of time to consider it, were it not that the legal advocates in disputed cases make considerable capital out of it ; and further, that it appears prominently in the water report which affords the motive for these remarks. Plainly, the same statement applies with equal exactness to each of the other determinations made with the view of ascertaining the presence or absence of sewage ; all such determinations being made with the object, not of detecting directly harmful matter, but of finding whether the character of the water is such that it may be the means of conveying infection.And yet it appears to have been overlooked that each grain of nitrogen in this form means very nearly six grains of calcium (or other) nitrate, and that the permanent hardness of the water is propor- tionately increased. I t would appear, therefore, a matter worth consideration whether a water containing thirty grains of calcium or magnesium nitrate per gallon -a very usual amount-should be passed as perfectly wholesome. 11. The question of the natural occurrence of nitrates in undoubtedly pure- that is, dietetically satisfactory-waters is one that merits more attention. It is asserted that these salts occur naturally in such quantity as to render their deter- mination meaningless for sanitary purposes. Now, on looking into this argument one finds that it consists, first, of sugges- tions of innocent sources of nitrates; secondly, of instances of pure waters containing nitrates.The possible sources of nitrates other than animal matters are : (a) Natural deposits of nitrates. ( b ) Ancient organic remains, or (‘ fossil sewage.” (c) Rain-water. (d) Vegetable matter. (a) That there is or can be a deposit of nitrates in any geological formation in our climate is scarcely conceivable, and has certainly never been demonstrated. It296 THE ANALYST. is established that nitrates are amongst the salts most easily washed out of the soil, and any accumulation in the more superficial strata-assuming that such could ever have been formed under different climatic conditions-must have been removed long before the era of water analysis, Moreover, under the most -frequently occurring conditions nitrates are not permanent, but speedily undergo decomposition under the influence partly of living organisms, partly of purely chemical agencies.Further, if this assumption were true, it would naturally be anticipated that deep borings would yieId water containing a higher proportion of nitrates than super- ficial wells. Nitrates are always found in greatest abundance at or near the surface, and in decreasing amount the further from the surface the point of supply is situated. I shall return to this point in connection with deep wells. (b) The possible production of nitrates from the fossil remains abundant in some formations has been frequently asserted, but I have been unable to find anything like evidence in support .The only -systematic attempt to determine this question with which I am acquainted is an investigation by Mr. Chas. Ekin (Joz~rn. Chem. Xoc., 1871, p. 64), in the course of which selected specimens of rocks and fossils, as well as spring waters from various formations, were examined, with the result that nitrogen was found in small quantities in material apparently out of reach of contamination. At the time, the view was expressed by Mr. Ekin that his results indicated that ‘‘ the previous sewage contamination theory ought to be considerably modified.” Both the methods adopted and the deductions drawn appear to be open to criticism; but the need for any is dispelled by a subsequent contribution to the subject by the same writer, in which he says (‘‘ Potable Water,” 2nd ed., 1880) : ‘( When the amount [of nitrogen as nitrates] exceeds -5 or 06 parts per 100,000, it points significantly to dangerous pollution ;” and again : ‘‘ This view of the im- portance to be attached to an abnormal quantity of nitrates has been formed in spite of a considerable predisposition to a contrary opinion, and has been literally forced upon the writer again and again by the investigation of cases which really leave no doubt in the matter.” The whole of this part of the question is obscured by a lingering remnant of the notion that any nitrogenous matter exposed to air may forthwith be directly oxidized with formation of nitrates; whereas the latter can practically only be formed in nature as the product of one of the steps of decomposition necessarily preceded by the earlier stages of putrefaction.TO suppose, therefore, that nitrates can arise from the oxidation of fossils implies that the latter are capable of putrefaction; in which case our palteeontological museums would require the intervention of the inspector of nuisances. Fossils may possibly retain traces of nitrogen ; but if so these traces simply constitute a non-putrescible residue, and there is no valid reason to suppose that at this period of time there is any possibility of further change. (c) The presence of nitrogen in rain-water in the shape of ammonia, nitrites, This is contrary, of course, to all experience.THE ANALYST. 297 and nitrates is a matter constantly coming under the notice of every water analyst and has been the subject of special investigation by many well-known chemists.The Rivers Pollution Commissioners devote a considerable part of their sixth report to this question, and their results briefly amount to this: That rain-water collected with suitable precautions may contain nitrogen in this shape in quantities ranging from -0028 to ~0875 grain per gallon, the average being -0238. This average quantity the Commissioners proposed to deduct from the nitrogen as nitrates, nitrites, and ammonia, found in natural waters, the remainder being. attributed to animal matter. Thus rain-water may contain nearly one-tenth of a grain of nitrogen per gallon, the whole of which might be converted into nitric acid under suitable conditions.On the other hand, it is to be noted that it is, as a rule, only near towns that this maximum is approached, owing, probably, to the presence of ammonia produced by the combustion of coal; and that in these towns the storm-water does not generally pass into the soil, but is diverted into the drainage system; whilst it is extremely improbable that where rain falls upon land covered with vegetation, much, if any, of the nitrogenous compounds escape assimilation. This is corroborated by the fact that analyses of water from tracts of uncultivated land out of reach of animal contamination show often an absence, and never more than minute traces, of nitrates. (d) I t is the practice of those writers who disregard the presence of nitrates to refer to their derivation from ( ( animal or vegetable organic matter ” as if the distinction were of no importance. From a sanitary point of view, however, it is manifestly very important to determine, if possible, whether there is any distinction to be drawn between these two classes of organic matter in this respect.Now, the proportion of saline ammonia to albuminoid ammonia is well known to afford a practical means of distinction between animal and vegetable contamination in water. Take, for example, the following instances of organic pollution, the results being stated in grains per gallon : A. B. Saline ammonia ... ... . . . -009 2.37 Albuminoid ammonia . . . ... . . . -168 0 14 A is a sample from a few inches of water remaining in an exhausted reservoir, the bottom of which is covered with a deposit of vegetable dbbris-not, however, entirely destitute of animal life, for iii is naiuraiiy full of infnsoria and entomostraca-exposed for many days to the abnormal temperature of this exceptional summer.This sample, therefore, is an enormously exaggerated instance of vegetable pollution, far in excess of anything that is likely to occur in connection with an ordinary water supply. B is sewage as discharged into a brook, not allowed to stagnate, and not placed under circumstances exmptionally favourable to decomposition. The permanent character of the vegetable as compared with the animal matter, and the sluggish development of ammonia in the case of the former, are here well illustrated. If, then, it is necessary for the formation of nitrates that there should be a sufficient supply of ammonia, it is easy to understand why these salts are practically298 THE ANALYST.derived from animal matter alone. It is not necessary for our present purpose to inquire into the reason of this difference between the two forms of organic matter, but the explanation is probably to be found not only in the smaller proportion of nitrogen, and the more permanent character of the nitrogenous constituents of vegetables, but also in the fact that these constituents are more effectually protected against the inroads of putrefactive organisms by the more resistant nature of the vegetable cell-wall. Corroborative evidence is again afforded by numerous analyses of moorland waters, where the rain not only falls upon land covered with vegetation, but is often stored in bogs and marshes, in intimate contact with vegetable matters, and yet issues practically destitute of ammonia, nitrates, and nitrites.Very instructive in this connection is a comparison of the results obtained by the Rivers Pollution Commissioners from the samples of water from gathering grounds out of reach of animal contamination with those afforded by waters from cultivated and inhabited districts : these results appear fully to justify the conclusion that I ‘ whilst; the oxidation of animal matters in solution in water yields abundance of nitrates and nitrites, vegetable matters under like circumstances yield none or mere traces of these compounds.” We have yet to consider the second division of the evidence relating to the presence of nitrates in pure water, namely, examples of waters of known purity containing nitrogen in this form.And here we meet with the difficulty that no kind of proof is given, as a rule, of the freedom from contamination of those waters that are selected for the purpose of illustrating this point; and as other analytical data are seldom given at the same time, no opportunity is afforded to the critic of forming an opinion as to the character of the water. Waiving, however, this point for the moment, if we examine the instances adduced by one of the most ardent opponents of nitrate determination, we find that the most pronounced specimen contains just 0.6 grain of nitrogen as nitric acid per gallon. Surely this affords no sufficient reason for ignoring the presence in well-water of ten, twenty, or even thirty times as much, implying a supply of nitrogen which, bearing in mind the quantity of water draining through a porous soil, assumes an almost commercial importance.I n the face of the inevitable conclusion that the bulk of the nitrates contained in such waters can have no other origin than animal matter, it seems to me that their presence is a matter calling for most serious consideration. Nor does the fact that fresh sewage contains no nitrates dispose of the advisa- bility of their determination when present ; for it is not, of course, suggested that the usual methods of detecting unoxidized nitrogen compounds should be neglected. I t may, perhaps, be well to state clearly that I am not for a moment advocating the determination of nitrates to the exclusion of any other operation that can throw light upon the character of a water. I am merely endeavouring to show that this item is an absolutely essential feature of every water analysis.It is now, I think,, sufficiently apparent that, as stated previously, nitrates are all but exclusively derived from the oxidation of animal matters. Bearing, then, inTHE ANALYST. 299 mind the danger besetting the ingestion of such matters, we have next to inquire how it can be maintained that water, containing nitrates obviously in excess of the maximum proportion that can be derived from the comparatively innocent sources reviewed in the preceding sections, can be held to be dietetically good. The only possible defence of this position would be a demonstration that during the conversion of the nitrogen of the animal matter into nitrates, the water necessarily undergoes such a process of purification as to remove the elements of danger which it is neces- sary to assume may accompany the original polluting substance.This brings us to the three remaining arguments against the determination of nitrates. 111. The suggestion that the process of oxidation involved in nitrification is in any true sense a destructive one appears to be a relic of the time when it was yet unsuspected that either the process itself or the communication of disease might be the work of living organisms, and could only be seriously advanced under a complete misapprehension of the process of nitrification, and a very unwarrantable confusion of the various forms of oxidation. Nitrification is itself essentially a physiological action on the part of living organisms, is completely arrested by a moderate rise of temperature, and is, in short, parallel in all respects with the formation of carbon dioxide in respiration.The process is carried out under conditions favouring microbic life in general, and especially conducive to the persistence in water of pathogenic forms for which moisture, an equable low temperature, and absence of light, are necessities. IV. I t is, then, further suggested that, nitrification being only carried out during percolation through soil, this latter process is a species of filtration during which all objectionable matters are removed from the water by mechanical retention, by chemical action, by the antagonism of other organisms, or simply by the failure of pathogenic organisms to persist in an unfavourable medium, all of which agencies may be supposed to have abundant opportunity of exercising their powers during the passage of polluted water through a considerable thickness of soil.Now, there is a considerable appearance of reason about this argument ; but to render it capable of practical application it is plainly necessary to define the minimum extent of such filtration necessary to effect purification, for we are now admittedly dealing with a water initially dangerously pollutsd; and then for the purposes of our present inquiry we have to ascertain how this minimum of filtration affects the ques- tion of nitrates, Several empirical attempts have been made to meet this difficulty, and the first that naturally occurs to one is the distinction between deep and shallow wells.A deep well is defined as one the whole supply to which enters at a point not less than 100 feet from the surface, provided that the water really percolates through the soil, and is not conducted from the surface by fissures, I t was assumed by the Rivers Pollution Commissioners (Sixth Report, p. 89), on not very satisfactory grounds, that such a water, even if originally polluted, would be so far purified by filtration as to be a wholesome drinking water. I t is, however, generally impossible to assure one’s self of the fulfilment of the above conditions, and any evidence of unoxidized organic inatter, or even of an exceptional amount of300 THE ANALYST.oxidized nitrogen compounds, was held by the Commissioners to show that they were not perfectly carried out. Then numerous investigators have suggested a limit of nitrogen (as nitrates) below which the evidence of pollution is too slight to be noteworthy; in other words, these chemists have suggested a chemical instead of a distance limit. This is generally placed at about 0.5 grain nitrogen per gallon. Thus we have seen that Mr. Ekin puts the maximum at -42 (0.6 part per 100,000); the Rivers Pollution Commissioners at 0.7 (1 part per 100,000), and so on. Lastly, we have the practical completion of nitrification, that is, the absence of significant quantities of unoxidized nitrogen, as the limit imposed by the holders of the views more immediately under discussion.Now, all these proposals are no doubt the outcome of large experience in water analysis, but they cannot be said to be established upon thoroughly reliable premisses; and as the necessary information may be obtained from direct experiment where the conditions are absolutely under controI, it appears to be very desirable to consider the question on this basis. Before doing so, however, I wish to point out that the distance or ‘( deep well ” limit, and the quantitative limit of 0.5 grain nitrogen per gallon, are in practical accord, and having been obtained independently are all the greater corroboration one of the other. Probably the fullest series of analyses of deep-well waters ever published occurs in the Sixth Report of the Rivers Po1lutio.n Comntissioners, already alluded t o ; but unfortunately there are included amongst them several analyses not deserving that name.Still, of 157 samples not polluted with fresh sewage, fourteen only appreciably exceed the limit of 0.5 grain nitrogen as nitrates, and these are shown by the accom- panying notes to be unsatisfactory in position, not sunk to the required depth, or otherwise not entirely in conformity with the definition. Some of them, indeed, have been closed on the ground of sewage contamination. Perhaps the best possible illustration, however, is afforded by the deep wells in the chalk from which the Kent Water Company supplies part of the Metropolis; and this evidence is all the more valuable because it goes far to refute one of those mis- statements which are copied with ever-increasing positiveness from one book to another until they are accepted as axioms i I refer to the idlegad abncrmal yield of nitrates by the chalk.One would be justified in interpreting the statements in many works to mean that there is hardly any limit to the proportion of nitrates a pure chalk water may exhibit. There is this much to be said in support of this assertion, that the chalk is probably of all formations the most suitable both in chemical composition and in physical structure for the active promotion of nitrification; and there is probably a greater yield of nitrates from a given amount of organic nitrogen, and a greater persistence of the nitrates so formed, than in any other formation.But it is no more true to say of the chalk that it furnishes nitratesper se, than it would be of any other formation. There must be abundant examples of chalk waters in the note- books of most Southern analysts showing no abnormal proportion of nitrates ; indeed, the average nitrio nitrogen in sixty-six samples, including several obviously pollutedTHE ANALYST. 301 waters, was determined by the Rivers Pollution Commissioners to be 0.42 grain per gallon, or somewhat less than the average of samples from the New Red Sandstone. However, to return to the Kent Water Company’s works, these consist of several wells ranging from 150 to 500 feet in depth, the upper part of each well to a distance of 70 to 100 feet from the surface being lined with cast-iron cylinders to exclude super- ficial impurities.The maximum proportion of nitrates in this water is given by the Rivers Pollution Commissioners as 0.38 grain per gallon, the average being 0.287 grain. This agrees well with the average of 0.25, calculated from a series of monthly analyses extending over a period of ten years, and recorded by the late Dr. Tidy (London Water Supply, 1868-1878). Compare with this the proportion of 1-45 grain of nitric nitrogen yielded by the water of another well belonging to this company, but not, I believe, used for public distribution, this well being only 70 feet deep, and not protected against surface drainage. Here, then, we have reasonable proof that water originally considerably con- taminated with the products of decomposition of animal matters, after having undergone an amount of natural filtration considered under one system to guarantee the elimination of dangerous materials, has, if we adopt the chemical limit, lost the chemical evidence of pollution.(To be continued.) Methylene Blue as a Reagent for Sugar in Urine. N. Wender. (Pharm. Post., 1893, xxvi. 393 ; through Chem. 2eit.)-One C.C. of the urine, previously diluted to 10 times its volume, is mixed with 1 C.C. of methylene-blue solution (1 gramme per litre) and 1 C.C. of normal potash solution in a test-tube; the mixture is diluted with 2 C.C. of water, and heated over a flame. The methylene blue will be completely decolorized if the original urine contained upwards of 0.5 per cent. of sugar.If the colour remain permanent the urine cannot be called diabetic. A. G. B. The Amount of Fat in the Milk of Mecklenburg Herds. P. Vieth. (Land- wirthschaftliche Annalen d. Mecklenburgischen Patriotischen, Vereins, 1893, xvii., 131.)-From 1878 to 1885 Prof. Fleischmann determined in the laboratory of the Raden Dairy Institute the specific gravity, fat, and total solids of the milk of the Raden herd of cattle; samples of morning and evening milk were examined weekly. The resuits are : 1878 1879 1880 1881 1882 1883 1884 1885 Variations. ... ... 2.84 to 3.93 ... ... 2.87 to 3.91 ... ... 2.92 to 3.82 ... ... 2.78 to 4.02 ... ... 2.89 to 3.58 ... ... 2.85 to 4.22 ... ... 3.04 to 3.95 ... ... 2.82 to 3.89 Averages. ... ... 3.40 ... ... 3.30 ... ... 3.27 ...... 3.24 ... ... 3.20 a .. ... 3.26 ... ... 3.30 ... ... 3-24 In the year 1886 the Government investigation was discontinued. In 1885 the Rostock Dairy Company was started. For the first year the quantity of milk yielded by each herd only was noted, but in 1886 the fat was estimated by302 THE ANALYST. Soxhlet's areometric method in weekly samples of morning and evening milk, and the monthly average calculated from these. The yearly averages are calculated from July 1 to June 30 in each year. Yearly Variations. Averages. 1887-88 ... ... 3.2 to 3.4 .., ... 3.33 1888-89 .:. ... 3.1 to 3.7 ... ... 3.43 1889-90 ... ... 3.3 to 3.8 ... ... 3-52 1890-91 ... ... 3-3 to 3.6 ... ... 3.46 The milk was supplied by 15 associates, and the variations in the composition The average monthly composi- of each is given in curves accompanying the paper.tion calculated from the whole of them is- Fat. July ... ... 3534% ) # October . . , ... 3.51 ,, December ... 3.49 ,, August ... ... 3.42 I , September ... 3.46 ,, November ... 3.59 ,# Fat. January ... 3.40% ,, February ... 3.40 ,, March ... ... 3.39 ,, April .-. ... 3-36 ,, May ... ... 3.37 ,, June ... ... 3.27 ,, AS the author has noticed in England, the amount of fat is highest in October and November and lowest in June. (See ANALYST, xvii. 84, and Journ. Roy. Agric. SOC., xxv., s.s., Part I.) NOTE BY ABSTRACTOR.-It is hardly necessary to draw attention to the fact that the percentages given are obtained by Soxhlet'slmethod, which gives about 0.25 per cent. less fat than Adams' process.H. D. R. H. D. R. Researches on the Adulteration of Olive-oil, V. Olivieri. (Stax. Sper. Ag. Ital., xxiv. 387.)-The author has examined 106 samples of genuine olive-oil exhibited at the Palermo National Exhibition of 1891-92. The amount of potash required for saponification varied from 19-05 per cent. to 19.50 per cent., and the iodine absorption from 79-0 per cent. to 83.2 per cent. The whole of the samples were examined in Amagat and Jean's oleorefractometer (see ANALYST, xv. 87) ; the variations found were from 0" to + 2". The following figures were yielded by the different oils examined by the author : Name of Oil, Deviation. Potash Absorption. Iodine Absorption. Olive.. . ... 0" to + 2" 19.05 to 19.50 79.0 to 83.2 Cotton ... + 18.0" 19.1 to 19-55 104 to 108 Sesame .,.+ 15.5" 18.9 to 19.05 105 to 107 Colza ... + 26.5" 17.7 to 17.8 99 to 106 Earthnut ... + 7.5" 19.1 to 19.6 101 to 105 Poppy ... + 28-5" 19.2 to 19.5 133 to 138 Olein " ... + 2.5" to + 4" 15.7 to 16-0 57.2 to 60.0 The olein examined was a bye-product of the manufacture of stearin candles, Mixtures were made &B follows : consisting of the liquid glycerides. 80% Olive 20% Cotton gave a deviation of ... + 4.5' 60% ,, 40% Colza ,, ,? $ 9 ,.* + 12" 75A ,, 25% Earthnut ,, ,# $ 9 ... + 2" 703 ,, 30% Sesame ,# ? 9 9 , ... + 4.5"THE ANALYST. 303 The author is of opinion that the oleorefractometer will be of use to detect con- siderable adulterations of olive oils; oils giving normal figures cannot always be passed as genuine without further examination.He relies on the iodine absorption to detect adulteration. H. D. R. NOTE BY ABSTRACTOR.-The maximum iodine absorption given by the author is low, as numerous cases of olive oils having iodine absorption of 87 per cent. to 88 per cent. have been recorded. Had he found such samples his conclusions would have doubtless been modified, H. D. R. Qualitative Examination of Phenacetin. C. Plat t. (Jour, Anal. and AppZied Chem., 1893, vii. 77-83.)-The melting-point of pure phenacetin should be very close to 135" C., and if it fall to 133" C. the sample may be suspected as impure, The presence of acetanilide is the commonest cause of a fall in the melting-point, 5 per cerit. of this impurity reducing the constant to 127" or 128" C. Inasmuch as the price of acetanilide is only one-fifteenth of that of phenacetin, it is sometimes added to increase the profit ; but the objection to it does not end here, for Schrceder has shovn that its decomposition in the system yields aniline.Antipyrin and paraphenetidin should also be looked for in phenacetin. The following tests will serve to identify phenacetin, and to prove its purity from the above adulterants : 1. Boil the sample with hydrochloric acid, dilute with water, cool, filter, and add two or three drops of potassium dichromate to the filtrate; if the sample be phenacetin, a ruby-red colour will be produced. 2. Boil with water, cool, filter, and add bromine water until the solution becomes yellow ; pure phenacetin solution will remain clear. 3. Phenacetin will give a red colour when boiled with hydrochloric acid and ferric chloride.4. Autenrieth and Hinsberg's test (ANALYST, 1892, 57). 5. Heat with alcohol and sulphuric acid; ethyl acetate will be evolved and recognised by its odour. At the same time aniline will be produced, and may be recognised by yielding phenylcarbamine when the solution is heated with chloroform and potash. 6. Alcohol will be evolved when phenacetin is boiled with potash; this dis- tinguishes it from acetanilide. 7. To a well-cooled solution in strong hydrochloric acid add chlorine water: phenacetin gives a red colour ; acetanilide a blue, which afterwards fades. 8. Potassium permanganate added to the hydrochloric acid solution gives a violet colour, which changes to dark ruby-red, with phenacetin, but a green colour with acetanilide.9. Weak chromic acid gives a red colour in a dilute hydrochloric acid solution of phenacetin, but a yellow colour, becoming dark-green, with one of acetanilide ; the dark-green solution gives a blue precipitate withjpotash. 10. The most delicate test for acetanilide in phenacetin is to heat with potash and chloroform, when acetanilide gives phenylcarbamine, but phenacetin does not.304 THE ANALYST. 11. The presence of antifebrin in phenacetin is detected by boiling the sample with 8 little water, cooling, filtering, and boiling the filtrate with a little nitrous acid and Plugge’s reagent (a solution of mercurous nitrate with a little nitrous acid). Antifebrin will be betrayed by the production of a red colour. 12. To detect paraphenetidin in phenacetin, melt 2.5 grammes of chloral hydrate in test-tube, and add 0.5 gramme of the sample ; pure phenacetin will dissolve to a colourless solution, becoming pink after some time.A trace of paraphenetidin will produce a dark violet to a reddish or bluish violet, according to the quantity present, A. G. B. Saponification of Fats by Strong Sulphuric Acid. P. Schatzmann and H. Kreis. (Chem. Zeit., 1893, xvii. 544, 545.)-The authors point out that Pinette (ANALYST, 1893, p. 145) has failed to make their method a success because he has used sulphuric acid which is too strong. It was stated in the original paper on the subject (ANALYST, Zoc. cit.) that acid of sp. gr. 1.825 is used. The acid is now judged to be of the correct strength, not by the hydrometer, but by the way in which it dissolves pure butter and oleo-margarine when used in the way described in the original paper.Under these conditions pure butter should dissolve to a clear solution immediately, and oleo-margarine in 2 to 3 minutes, if the acid be of the correct strength. An acid which is too strong or too dilute will dissolve the fats too quickly or too slowly. The acid which the authors use contains 91.53 per cent, H,SO,, and forms an excellent qualitative test for margarine in butter fat. This acid gives good Reichert- Meissl numbers, and the authors insist that neither oxidation of sulphurous acid, nor elimination of it by a current of air or other gas (ANALYST, Zoc. cit.), is necessary. That oxidation by permanganate before distillation gives too low a result is shown by the following figures : Commercial oil of vitriol is generally too strong.Reicher t-Meissl Method. Pinette Method. Butter I. ... ... 29.1 18.8 ,, 11. .U ... 28.6 17.6 Margarine . . . ... 7.1 5.3 A. G. B. The Separation of Copper from Cadmium by the Iodide Method. P. E. Browning. (Amer; J, Science; 1893, xlvi. 280-283.)-The quantitative precipita- tion of copper as cuprous iodide is difficult on account of the perceptible solubility of the precipitate. Flajolot (J.f. Pmkt. Ch,em. Ixi. 105) recommends that the solu- tion containing copper be brought to acidity with sulphuric acid, that a consider- able excess of sulphurous acid be added, and that the precipitation be effected by hydriodic acid. The author made a series of experiments, using about 0.12 grm.of copper for each, and precipitating under various conditions. He found a considerable deficiency of copper in the precipitate, save when the following precautions were adopted: The solution of the copper as sulphate, measuring about 25 c.c., is pre- cipitated with 1.2 grms. of potassium iodide, the solution containing the precipitate being then evaporated to dryness to expel the free iodine. The residue is treatedTHE ANALYST. 305 with water, filtered on a Gooch filter, and well washed with hot or cold water. The asbestos constituting the filter should be fairly thick, and not allowed to run dry during the filtration, lest the filtrate tend to be turbid. The crucible and its con- tents are then dried in an air-bath at 120"-150" C. to constant weight. The possibility of precipitating copper quantitatively as cuprous iodide having thus been settled, it was found that the same method is applicable in the presence of varying proportions of cadmium as sulphate, and thus constituted a means of separation, The subsequent precipitation of the cadmium in the filtrate presents some difficulty, as when thrown down as sulphide in either acid or ammoniacal solution it filters slowly, a serious disadvantage, inasmuch as tedious washing to remove alkaline salts is inevitable.The author finally found that precipitation by means of sodium carbonate in a boiling solution-heating being continued until the precipitate became granular--was best under the conditions obtaining. The car- bonate was collected on a Gooch filter, to- avoid reduction on ignition, and heated until converted into oxide and weighed. B.B. Determination of Nitric Acid. C. F. Roberts, (Amer. J. Science, 1893, xlvi. 126-134.)-The paper consists of a study of the conditions of accuracy of the Schloesing process for the estimation of nitrates, the following conclusions behg arrived at : (1) The nitric oxide should be passed through a solution of potassium iodide before collection, to decompose higher oxides of nitrogen. (2) The nitric oxide may be collected over caustic soda, as proposed by Tie- mann, but it should not be left long in contact with this reagent, as it is perceptibly absorbed thereby. B. B. Rapid Method for the Detection of Iron in Commercial Copper Sulphate. G. Griggi. (Boll. Chim. Farmac., 1893, xxxii. 549 ; through Chem. Zeit.)--5 C.C. of an aqueous solution (1 : 5) of the copper sulphate to be tested are poured into a test- tube, and 5 C.C. of an ethereal solution of salicylic acid (1 : 10) gently added. Should the copper sulphate be free from iron, the junction of the two solutions remains colourless, but in the presence of iron a violet colour appears, varying in intensity according to the amount of iron present. B. B. The Content of Lecithin in Butter. E. Wrampelmeyer. (Landw. 'Ver- suchs., 1893, xlii. 437 ; through Chem. 2eit.)-The hope of discriminating between butter and margarine by means of their respective contents of lecithin cannot be realized, for although a difference exists, it is by no means constant. Thus, the author found an amount of phosphoric acid in the ash of butter corresponding to 0.045% of the original butter. These results were obtained on the unfiltered fats, and therefore included the phosphoric acid in the salts accompanying the fat itself. Experiments on the filtered fats showed that at most a trace of phosphoric acid occurred in margarine, while butter fat, although contain- ing more than a trace, was poorer in this constituent than the butter from which it was derived. Moreover, the percentage fluctuated, and thus no useful standard could Margarine similarly treated gave 0.016%306 THE ANALYST. be fixed. The quantity of lecithin caIculated from the amount of phosphoric acid in the filtered fat averaged 0.017%, in place of tenfold that amount hitherto accepted 8s being present. B. B.

ISSN:0003-2654    

DOI:10.1039/AN8931800293

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

306 THE ANALYST. “ SUBSTANCE, NATURE, AND QUALITY.” IMPORTANT LEGAL DECISION. HIGH COURT OF JUSTICE.-QUEEN’S BENCH DIVISION. BEFORE MR. JUSTICE CHARLES AND MR. JUSTICE WRIGHT. BAKEWELL, Appellant - DAVIS, Respondepelzt. (From the Times, November 7, 1893.) THIS case yesterday raised a question novel and important under the Adulteration Acts- that a vendor of milk which is undoubtedly poor, but which is not shown to have been made 60 by any admixture of water, etc., and can only be inferred from the very poorness to be SO from withdrawal of cream, can be convicted under the Adulteratiou Acts. I t was an appeal against a conviction under the Adulteration Acts of a farmer for selling milk “containing 22 per cent. of fat less than natural.” I t was proved that the prosecutor, an inspector, pro- cured a sample of milk from a churn of milk in course of delivery a t a railway-station in Birmingham from Bakewell to the North Staffordshire Dairy Company, in pursuance of a contract.The churn had a label on it, L‘ The contents of this churn are warranted to be new and pure milk.” The public analyst, in whose presence the material operations took place, proved that there mere in the milk 88 parts and a fraction of water, and that the total solids were 11, 35 per cent. of which solids, not fat, were 8.66, and solids, fat, 2.69, and he stated that the sale of any milk in which the percentage of fat was less than 3 per cent., was fraudulent, but he admitted that from the dryness of the season (this was in April last), poor feeding, or other causes, the f a t in the milk from one cow might fall below that standard, and he had known a cow yield only 2.6 per cent.of fat. But he was of opinion that there had been no actual adulteration by mixture of water. The appellant gave evidence that the milk was from a dairy of twenty-six cows, and that he had taken no cream from it, and ascribed the poorness of the milk to the dryness of the season or the quality of the food, and other evidence was given to show that the poorness of the milk arose from natural causes. It was contended that, as there was no evidence of actual adulteration, and the poorness of the milk might be from natural causelp, the defendant could not be convicted. The magistrates, however, were of opinion that the appellant, though he did not know of anything wrong in the milk, did not prove that the milk was genuine or that the absence of fat arose from natural causes.They accordingly found that the milk was not of the nature, substance and quality of the article demanded, and that it had been sold by the appellant under a contract of sale to the prejudice of the purchaser, and they convicted him accordingly, but they stated a case to raise the question whether their conviction was correct in point of law. Mr. Poland, Q.C. (with Mr. Wills), appeared for the appellant in support of his appeal, and urged that the magistrates had not found as a fact that any cream or fat had been abstracted from the milk, and selling poor milk was, he said, no offence, iinless i t was so by adulteration or withdrawal.Mr. Jelf, Q.C. (with Mr. William Graham and Mr. Hugo Young), appeared for the prose- cutor in support of the conviction, and urged that the certificate of the analyst was sufficient, and showed ample grounds for conviction in staiing that the milk was not pure and genuine. Mr. Wills, in reply, urged that there was no finding that the milk was poor by reason of withdrawal of cream. Neither abstraction of cream nor addition of water was charged orTHE ANALYST. 307 found, and no offence under the Act was charged, for selling poor milk per se was not an offence. [Mr. Justice Charles : There are cases in which a seller may be liable without guilty know- ledge.-Mr. Justice Wright : Suppose the man half starves his corn, and so the milk is poor. Has he a right to sell milk not genuine, nor of the nature or quality of good milk?] The conviction is under section 9, which requires a bad intent, [Mr.Justice Charles : No ; under section 6, ‘ I not of the substance, nature, or quality of the article demanded.” It follows the words of that section.] The analyst’s certificate really, though indirectly, charges abstraction, as it speaks of abstraction as a fraud, and of that there was no evidence, and so i t is bad, for by the Act the certificate is made evidence. [Mr. Justice Charles : Only of (‘the facts stated.” I t may be that the observations ought not to have been inserted.-Mr. Justice Wright : There was no evidence of any moral fraud or any intentional injury.] No evidence of abstraction of cream, and yet i t is indirectly charged in the certificate.Mr. Justice Charles, in giving judgment, said the defendant was charged, it was quite clear, under section 6, as to selling something not of the subst>ance, nature, or quality of the article demanded. The analyst’s certificate was to the effect that the milk contained much less cream than natural and usual, and less than a certain proportion, he added, would be fraudulent. That observation was unauthorized, but i t was urged that it rendered the certificate invalid altogether, as it conveyed a charge of wilful abstraction. The magistrates, however, had expressly acquitted the defendant of that, and he did not think the analyst’s statement was a statement of fact. I t was a mere statement of opinion, which the magistrates did not adopt or act upon. The main question was whether it was sufficient, and it in effect stated the results of the analysis. The result of the analyst’s certificate was that the proportion of cream or fat in the milk was less than natural or usual. That was the proper course, and it showed that, an offence against the statute had been committed. Mr. Justice Wright concurred, observing that, as to the analyst’s certificate, it was only in cases of adulteration that it was necessary to enter into the proportion of ingredients as show- ing fraud. He did not think, therefore, that the certificate was altogether bad or void. Appeal accordingly dismissed, and conviction upheld.

ISSN:0003-2654    

DOI:10.1039/AN8931800306

出版商:RSC    

年代:1893

数据来源: RSC

摘要:

THE ANALYST. 307 REVIEWS. REACTIONS : A SELECTION OF ORGANIC CHEMICAL PREPARATIONS IMPORTANT TO PHARMACY IN REGARD TO THEIR BEHAVIOUR TO COMMONLY-USED REAUENTS. By F. A. FLOCKIGER, Ph.D., M.D. Translated, revised, and enlarged by J. B. NAGELVOORT. Authorized English edition. Detroit, Mich., U. S.A. : George S. Davis. 1893. Price 2 dollars. This book is one which, from the high repute of the author, will receive a welcome at the hands of most practising analysts. I t contains succinct descrip- tions of the properties of and tests for a variety of organic preparations used in pharmacy. In the translator’s preface it is stated that “Very elaborate and full information on many articles treated of in this small volume, in a modest way, appear in the recently published second part of vol.iii. of Allen’s ‘ Comm. Org Analysis,’ and in Guareschi’s Introduzione all0 Studio degli Alcaloidi,’ Torino, 1892. Where the statements of Allen and Fliickiger or other authorities are not concordant, I have given the results of personal experience. This has given me an opportunity to decide some few moot problems in analytical work.” The spelling adopted for308 THE ANALYST scientific and chemical words is that laid down by the American Association for the Advancement of Science, 1891, and it seems a great pity that this barbarous plan has received the sanction of the translator. It is difficult to perceive the advantage of spelling chloride ” without the final “ e,” of writing sulfur ” for sulphur, and still more to be deprecated is the system of dropping the final e ” for bodies of basic nature, such as morphine, strychnine and berberine.Some of the translation of scientific terms from the German cannot be regarded as happy, or even accurate. For instance, the rendering (on page 118) of sulphobenzaminsauresammoniak ” as “ sulphobenzoic ammonia ;” and of ‘( ferri- sulphobenzaminat ” as c ( sulpho-benzoate of iron.” Again, on the following page, c c nitro-prussid-sodium ” is neither English nor elegant. The work is admirably printed, and both the empirical and structural formula of most preparations are given. The tests are described tersely, but with amply sufficient working detail, and the conditions of success are clearly laid down. Altogether, the work is to be recommended as a most useful book of reference, containing in a compact form a large amount of information on articles the examina- tion of which is troublesome and definite information widely distributed or difficult to obtain.A. H. A. A GUIDE TO THE EXAMINATION OF THE URINE. By J. WICKHAM LEGG, F.R.C.P. Edited and revised by H. LEWIS JONES, M.A., M.D., This well-known handbook, which has now reached its seventh edition, has for many years enjoyed a well-deserved popularity amongst medical practitioners and students. The present edition has been carefully revised, and in part rewritten, by Dr. Jones. Without pretending to be an exhaustive treatise on urine, it contains sufficient information for the ordinary requirements of the clinical clerk or the busy practitioner. The various methods described, though given briefly and concisely, contain all the necessary details for their successful execution. The information given is thoroughly accurate, reliable, and well up to date.I n the chapter on the use of the polariscope for the determination of glucose or albumin in the urine, it is difficult to discover what form of instrument is referred to. Any instrument with a scale for cane-sugar would obviously give erroneous indications for glucose or albumin. The only instrument we are acquainted with which gives % direct reding in percentages of glucose or albumin is the Mitscherlich half-shadow, made by Schmidt and Hiinsch. To attain this object a set of tubes of special length are supplied with this cheap and handy little instrument for the use of medical practi- tioners. The book is neatly printed, well illustrated, and of a handy size. We can cordially recommend it as tl reliable “Guide.” Seventh edition. M.R.C.P. London : H. K. Lewis. Price 3s. 6d. W. J. S. APPOINTMENT, Mr. W. W. Fisher, M.A. (Oxon.), F.I.C., Public Analyst to the County of Oxford, has been appointed by the County Council as the District Agricultural Analyst under the Fertilizers and Feeding Stuffs Act, which comes into force on January 1, 1894.

ISSN:0003-2654    

DOI:10.1039/AN8931800307

出版商:RSC    

年代:1893

数据来源: RSC