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Abstracts of the Proceedings of the Chemical Society, Vol. 3, No. 38 |
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Proceedings of the Chemical Society, London,
Volume 3,
Issue 38,
1887,
Page 63-72
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摘要:
ABSTRACTS OF THE PROCEEDINGS CHEMICAL SOCIETY. No. 38. Session 1887-88. May 5th, 1887. Mr. William Crookes, F.R.S., President, in the Chair. Messrs. T. Cooksey, George Robertson, David Wilson, Jun., and George Collar were formally admitted Fellows of the Society. Certificates were read for the first time in favour of Messrs. Hugh Barclay, Rose Hill, Harrington, Cumberland ; John Edward Green, 68, Portland Road, Holland Park, W. ; William Marshall, 7, Walter Street, Nottingham ; Frederick Lawrence Overend, B.A., Blair Lodge School, Polmont, N.B. ; J. Stanley Phillips, Wentworth, Upper Long Ditton, Surrey ; Walter S1ielle~- Spencer, 142, Clift,on Street, Brooks Bar, Manchester ; Charles Ernest Stedman, Williamstown, Mel-bourne. The following Papers were read :-41.‘‘A Contribution to the Study of We11 Water.” By R. Warington, P.R.S. The proportion of chlorine in the rain water at Rothamsted is 2 per million ; the proportion of total combined nitrogen about 0.7 per million. Of 31 inches of rain, annually falling on a bare clay soil, 17 inches have evaporated and 14 inches percolated below 5 feet. Drainage chiefly occurs between October and February. The quantity of chlorine in the drainage from 5 feet of soil is the same as that in the rain, but the proportion is doubled in consequence of evaporation. The proportion of nitrogen as nitrates in the drainage water from 5 feet of bare clay ,soil has averaged 107 per million. The produc- tion of nitrates in the soil is chiefly during summer; the principal discharge of nitrates as drainage is in the autumn. When land is covered with vegetation evaporation is increased, and the winter drainage commences at a later period.Evaporation being increased, the chlorine in the drainage water may also be increased. The drainage from the Rothamsted unmanured wheat land contains 6 per million of chlorine ; the drainage from the plot manured with farmyard manure, 7.3 per million. While vegetation is active no nitrates are found in the drainage water from the unmnnured wheat ; the nitrates reappear in autumn, after harvest. The average propor- tion of nitrogen as nitrates in the drainage from unmanured wheat is 3.4 per million; from wheat receiving farmyard mannre, 5.8 per million. These are minimum numbers.With rain containing the amount of chlorine found at Rothamsted, the average proportion of chlorine in drainage water can hardly exceed 8 per million. The pure well waters of Harpenden contain a minimum of 4.4 of nitric nitragen per million; this, therefore, is the average amount in the drainage water of the district. The deep wells in the chalk of Harpenden derive their main supply from a flow of underground water proceeding from north-west to south-east. Each well has besides its own local drainage. The pure well waters contain about 11 per million of chlorine; fhis amount does not sensibly vary throughout the year. Wells contami- nated by sewage are generally at their maximum purity in October. They may show a commencement of a rise in chlorides one or two months after active autumn drainage has commenced.All through the drainage season, the effeot of one month’s drainage is not mani- fested in the well water till the following month. The maximum of chlorides in the contaminated wells occurs after the end of the drainage season-usually in March. The nitrates and chlorides increase at a nearly equal rate during the early months of t!he drainage season. If active drainage continues for three months, a great increase in the proportion of nitrates will nsiially then take place, and this relative excess of nitrates ib: maintained for some months, The proportion of nitrates to chlorides varies considerably in different, contaminated wells.The sewage for poorly fed popula- tion yields a high proportion of chlorides to nitrates. Stable sewage furnishes appayently a high proportion of nitrates to chlorides. The old sewage contamination of deep wells is generally more or less chloric, chlorides being more permanent than nitrates. The well waters of Harpenden contain the nitrifying organism in small proportion ; it is probably derived from surface soil which has fallen in. 111 the Contaminated waters the quantity of silica is not increased, and the quantity of carbonates but little increased. Lime is consi-derably increased, and magnesia still more. Nitrates, chlorides and sulphates are largely increased. On comparing the low proportion of chlorine found in the pure chalk waters of Harpenden, near the edge of the London basin, with the amount found in other chalk waters, and especially with the chalk waters beneath the London clay ; and considering further the proportion of chlorides which can possibly be contributed by rain : it appears highly probable that a portion of the chlorides in chalk water, and probably in the water of other strata, is derived from a residue of sea-salt remaining in the rock.The proportion of nitrates found in the waters of uncontaminated wells and springs in the permeable strata of Etiglaud is fairly con- stant; it indicates an average loss to the soil of about 7 Ibs, of nitrogen per acre per annum. 42. ‘LCrystals in Rasic-Converter Slag.” By 3. E. Stead and C. H. Ridsdale.The authors describe a variety of crystals found near the centre of blocks of basic-converter slag, weighing 40-50 c wts. each, which had cooled slowly. Xo. 1. Large, well-formed, flat square crystals of a faint-yellowish colour, consisting ementially of the phosphate 4Ca0-P20, ; these have also been described by Hilgenstock. No. 2. Blue crystals, previously noticed by Groddeck and Brock-mann; these appear to be a double calcium silicate and phosphate, Ca0*P,06,Ca0*Si0,. Vanadium protoxide was present to the extent of 1.64 per cent. No. 3. Feathery or fern-like crystals ; these are remarkable as they contain under 4 per cent. of acid oxides and over 35 per cent. of hRic oxides-chiefl y of calcium, magnesium, iron (protoxide and peroxide) and manganese.No. 4. Hexagonal, needle-shaped lemon-coloured crystals, which appear to consist of about 86 per cent. 4CaO*P205 with 10-11 per cent. of silicates of metallic oxides. Nos. 5 and 6. Two varieties of flat black needles, the one magnetic, the other not. No. 5 contained about 10 per cent. CaO.Al203, 45 per cent. 3CaO*Be304and 33.5 per cent. 3CaO*Fe,03. No. 6 contained about 15 per cent. Ca0*A1,03 and 13 per cent. SCaO*Fe,O,. DTSCUSSION. In reply to a question by Mr. Thompson, Mr. RIDSDALEstated that Mr. Meiers had determined the crpt alline forms of the substances which had been described, and had examined them hi polarised light. In reply to Mr. Nettlefold, he said that they were of opinion that the whole of the phosphorus was present as 4CaO*P,O,.43. " Note on the Influence of Temperature on the Heat of Disso- lution of Salts in Water." By William A. Tilden, D.Sc., F.R.S. In a paper which appears under this title in the April number of the Transactions, Mr. Pickering reviews the experiments which he had previously published upon the same subject, and so far modifies the conclusions which he had drawn from those experiments as to admit that the lines representing the heat of dissolution of various salts at successive temperatures do not consist of a series of curves following one another at irregular intervals. But Mr. Pickering maintains that the new experiments now published lead to a result which only differs in degree from his fornier conclusion and involves admissions which are essentially of the same character as those which he has abandoned.His main conclusion will be best expressed in his own words (p. 335) :-" The heat of dissolution of a salt increases uniformly with the temperature up to a certain point, when the rate of increase is suddenly lowered, and this fresh rate continues uniform till lowered again at some higher temperature," &c. The consequence of this is that the graphic representation of the results must, according to the author, consist of two or more straight lines, which in the cases which he has examined, and within the limits of temperature to which his experiments have been confined, meet at 8-10', or in some cases at higher temperatures. And although the suggestion was made by Dr.Alder Wright, at the discussion which followed the reading of the paper, that the results might be repre- sented by continuous curves without these breaks, the author delibe- rately rejects this suggestion, and adds a postscript to his paper emphasising his own view. The experimental work upon which this conclusion is based is, if not quite unimpeachable, at any rate of a high order of excellence, surpassing any other published work on the same subject within my knowledge. It is only in the interpretation of the results that I veriture to differ from Mr. Pickering, but I think it is so plain that his main proposition is untenable, that I feel it desirable to direct attention to the question whilst the work is fresh in the recollection of the Society.Without any desire to be hypercritical, I think some exception might be taken to the way in which the means appear to have been arrived at. Instead of taking the arithmetical means of the values resulting from experiments performed at the several t'emperatures, the mean results have been deduced from the lines representing the various series, whether experiments were done at all the points or not (p. 304). The effect of this is naturally to straighten out the line between temperatures where experiments were not made. I may also remark that in the statement of the differences (post- script, p. 336) between the values calculated from the equat.ion for the cui've and the author's values, the word " observed " values must be understood as these " mean '' observed values which are not the exact mean values for each temperature.But after all this way of calculating affects the values of the mean to a very small extent, and has not destroyed their significance. Taking Mr. Pickering's own figures as representing the mean experimental results at the succes- sive temperatures, and simply plotting them out on squared paper, I submit that inspection is sufficient to show that every one of his series conforms to a continuous curve, which, considering the diffi- culties of the work, is generally quite remarkably smooth and free from irregularities. With reference to potassium chloride, the author remarks (p. 304) that " the sixteen mean results from 10-25" inclusive evidently form a straight line," and that the experiments below 9" forrn another straight line.To this I demur. I do not see how such an idea could have arisen, unless it was from the differences tabulated on p. 306, from which it appears that the increase in the value of M per degree drops from 50 cal. between 8" and 9" to 42 cal. between 9" and 10". Looking at other parts of the table, however, it will be noticed that even greater irregularities occur, as for instance-at 16-17'" the difference is 33 cal. 17-18 4577 37 18-19 9, 36 9, If a fall of 8 cal. at 8" to 9" is held to justify the assumption of a break in the line at this point, why should not another break be accepted when there is a rise of 12cal., or a fall of 9 cal.in the rate at the temperatures referred to ? Similar remarks apply in other cases. Potassium nitrahe, for example, shows a change in the rate of increase- from 40 cal. at 12-12" to 23 ,, 13-14 It is not clear why the break should be introduced here, when at only one degree higher there is a change of greater amount, viz. :-from 23 cal. at 13-14" to 42 ,, 14-15 and yet no corresponding change is recognised in the curve. In discussing these cnrves, I have added the graphic representation of all the experiments, in order that they may be compared with the means, and that no injustice may be done to the author's view. Again in the case of sodium chloride the mean differences given in the table (p. 308) seem to indicate, if any, four rather than two straight lines, the value being- 3-7O 44.; cal.7-11" 38.0 ?, 11-18 31.7 ,, 18-25 29-5 ,, Though the curves are somewhat irregular in some of the other cases, especially that of sodium carbonate, the hypothesis of sudden breaks is not supported sufficiently to make it acceptable in the face of all the probabilities pointing the other way. Such irregularities might naturally be expected in work of this nature, surrounded with diffi-culties as it is. Mr. Pickering criticises severely the results I obtained in the attempt to get determinations of the heat of dissolution over a, con-siderable range of temperature. I am indebted to Mr. Pickering for reminding me of the necessary validity of the formula of Person, which shows the dependence of thermochemical effects upon tempera-ture.The discrepancy between the calculated values in that paper and the experimental results arose from the mistake of assuming the values for the specific heats of the several solutions to be practically constant throughout, whereas they increase wihh rise of temperature, though to an extent which, according to the experiments of Marignac, is verysmall, from about 20" C. to 50". But this does not destroy the experimental numbers which, though subject to a general error which makes them all somewhat too low, are consistent among them- selves, and support the conclusion that the rate at which the heat of dissolution is influenced by temperature diminishes as the temperature rises.Fortunately this accords with the results of Mr. Pickering's own work, whether we do or do not adopt the hypothesis which he prefers, thak the changes occur suddenly. In my opinion all $he pro- babilities, in addition to Mr. Pickerfng's own resiilts, indicate that the heat of dissolution of a salt in water is a continuous function of the temperature. D1scuss10w. Mr. PICKERIRG,in reply, said that, after a very careful re-examina- tion of his results, he found it impossible to accept Professor Tilden's interpretation of them. In the first place he defended the method which he had employed in deducing mean values: this consisted in separately plotting each series of experiments by drawifig lines to connect the various values of each series, and deducing the final mean by taking the mean of the values given by these lines at each degree; and it was to be noted that the means were not deduced from the lines representing the individual series after the irregulari- ties in them had been smoothed out, as in the dotted lines in Plate I, as Professor Tilden appeared to think they were-probably through a want of clearness in the explanation given at p.304 of the speaker's paper. The method described would give unfair results in the event of one series containing a far larger number of determinations than anot'her, and to avoid this he had never a.pplied the method when a greater interval than 2" separated the successive experiments in any series.Though not perfect, this method is certainly the fairest which can be adopted, and beyond comparison much fairer than that suggested by Professor Tilden. Two series, consisting of experiments at alternate degrees and free from any experimental error, except that made in standardising the thermometers (which would cause the results of one series to be uniformly above, and those of the other uniformly below the truth), would each yield a straight line, if such were the nature of the true results, whereas their mean deduced by Professor Tilden's method would be a wavy line, and was obviously incorrect. Mr. Pickering said, that the concordance between his results and the curve or straight line method of representing them was so close that it was quite impossible by mere inspection of a diagram to decide which method was the best.The whole question depended on the magnitude of the average error in the two cases, and Professor Tilden had brought forward no numbers to show that a curve indi- cated a smaller error than straight lines. On the other hand, Mr. Pickcring had examined the average error in the two cases very care- fully. In the additional note to his paper he had shown that a curve (deduced from the actual results just as the straight lines were deduced from the actual results) did not agree with themean results so well as his siraight lines ; in the six cases which he examined the curve would represent a very considerable increase in the average error, and at the same time the sign of the error in the individual experiments was not positive arid negative promiscuously as in the straight line diagram, but errors of like sign were grouped together, the numbers deduced from the curve being above the actual results throughout a considerable range and then below them throughout another considerable range.Mr. Pickering had examined in the same way the results of each individual series performed with potassium chloride ; t,he average errors, according to the two methods of representing the results, were :- i0 Straight line. Cume. '08A ............. 4.7 cal. 5.3 cal. '61A ............. 4.0 ,, 5.7 9, '08B ............. 1.3 ,, 4.7 Y,'61B ............. 4.6 ,, -Thus in every case the curve did not represerrt the results so closely as the straight line.With series '61B the " curve " equation obtained represented a practically straight line. Another way in which he had attempted to investigate the question was to find the equations which represented those portions of the diagmm which he considered straight (from 9-25' with potassium chloride), and to see whether they gave a curve which could by any meam represent the other results (below 9"). The various values of /j the equation to the curve (1+ at -+ ,379) which he obtained were- Mean of 9 equations from series '08A .......... + 0'094 8 ,, 'G1A .......... -0.056'7 7' 7, 1' ,)2 '08A .......... + 0994 Y' 772 ,, '61A .......... + 0.6'74 _I Mean (weighted according to number of cxperi-ments included) ..........................+ 0.025 which value represents a line so nearly straight that it would deviate from straightness by only 4 cal, from 9-25', or 6 cal. from 3-25', whereas the actual results show a deviation of' 152 cal. between these East-mentioned limite. The results from 9-25' are, therefore, not conformable with those from 9-3". Thus in every way in which the results are examined they undoubtedly favour the straightl line as opposed to the curve method of representation. In answer to Professor Tilden's question referring to the results given in Table I, Mr. Yickering said that he thought it obvious why he should have taken the increase of 42 to 50 cal. (9-8") as signifi-carit of a truealteration in the rate, and should not.have regarded the diminution of 45-33 cal. (18-1 7') as having any significance at all.: in the latter case the difference of 45 cal, is evidently an exceptionally high result, unsupported by any other observation, which when combined with the differences imniediately preceding and following it (36 and 33 eal.) gives the same mean as 16 differ-ences from 25" to 9", whereas the difference of 50 cal,, while higher than any differences preceding it, is identical with the mean of the five differences which succeed it (8-3"). He thought that, no theoretical speculation should induce us to reject the more coiarect method of representing his results in 71 favour of the less correct method. Finally he pointed out that,, although the influence of temperature on any chemical change is represented by a curve, this curve really occupies but a very small proportion of a diagram representing the effect of temperature from the absolute zero to the highest known temperatures, and that this diagram consists of practically straight lines inclined to each other at different angles, and joined by curves, presenting an appearance, when reduced to the same scale, precisely analogous to that which he considered his dissolution results presented.44. “ The Distribution of Lead in the Brains of two Factory Operatives Dying Suddenly.” By A. Wynter Blyth. At R certain lead factory in the East of London five cases of more or less sudden death at different dates have been attributed to the effects of lead.In two of the cases the author had an opportunity of making a toxicological investigation. In the one case 24-25 mgrms. of lead sulphate was separated from tlhe liver and 5.4 mgrms. from one kidney ; there was also lead in the brain. In the second case investigated, occurring about a year after the first, the brain was more exhaustively examined, the cerebrum and cerebellum being treated separately and divided up by suitable means into white matter, kephalin, ether extract, substances soluble in cold alcohol and albuminoid residue, and the lead determined in each. Cerebrum, 460% grams. Cerebellum, 156.2 grams. Aqueous extract.. .......... 1.1mgrms. 0.4 PbSOa. White matter (kephalin-free) -5.0 79 Kephalin .................. 1.5 ,, 6.0 99 Ether extract (from which kephalin had been precipi- tated) ..................--Substances soluble in cold alto-h~l...................... --Albuminoid residue ........ 40.0 ?, 6’0 79 Calculated on the whole cerebrum this would amount to 99.7 mgrms., or a possible total for the whole brain of 117.2 mgrms. PbSOa. There has hitherto been no reasonable hypothesis to explain the profound nervous effects of the assimilation of minute qnantities of lead, but if it is allowed that lead forms definite compounds with essential portions of the nervous system, it may then be assumed that in effect it, withdraws such portions from the body ; in other words, the symptoms are produced not by poisoning in the ordinary sense of the term.but rather by destruction-a destruction it may be of im- portant nerve centres. 72 $5. “ Researches on Silicon Compounds and their Derivatives. A New Chlorobromide of Silicon.” By J.Emerson Reynolds,M.D., F.R.S. In purifying a large quantity of silicon tetrabromide prepared by means of crude bromine, the author has separated a portion boiling at 140-141”, of the relative density 2.432, which analysis shows to be the chlorobromide of the formula SiBr,Cl. Titles of Papers of interest to Chemists recently read before Societies in the United Kingdom :-‘‘Processes of Refrigeration.” By J. J. Coleman. ‘‘ Chemical Affinity and Solution.” By Mi-. Wm. Durham. ‘‘Researches on Micro-organisms, including Ideas of a new Method for their Destruction in certain cases of Contagious Disease.” By Dr.A. B. Griffiths. “ The Increase of Electrolytic Polarisation.” By Mr. W. Peddie. ‘‘Further Determinations of the Effect of Pressure on the Maxi- mum Density Point of Water.” By Professor Tait. “Note on Hoar Frost.” By Mr. John Aitken. ‘‘On the Influence of Certain Raps of the Solar Spectrum on Root Absorption and the Growth of Plants.” By Dr. A. B. Griffiths. “ On Ice and Brine, and on the Distribution of Temperature in the Antarctic Ocean,” By Mr. J. Y. Buchanan. “Note on Cobaltic Alums.” By Mr. Hugh Marshall. ‘L On the Physical Properties Gf Methyl Alcohol.” By Professor Dittmar and Mr. C. A. Fawsitt. ‘‘On the Instability of the Double Salts, M”XO4,R’,SOa,6H,O, of the Magnesium Series.” By Professor Dittmar.‘(A Diatomaceous Deposit from North Tolsta-Lews.” By Mr. John Rattray. Royal Societly of Edinburgh, Jan.-May, 1887. At the next Meeting on May 19th there will be a ballot for the election of Fellows, and the following Papers will be read :-“ The Formation of Hyponitrates.” By Professor Dunstan and T. S. Dymond. “ Ozone from pnre Oxygen; its Production and its Action on Mercury, with a Note on the Silent Discharge of Electricity.” ByW. A. Shenstone and J. T. Cundall. “The Thermal Results of Neutralisation and their Bearing on the Nature of Solution and the Theory of Residual Valencx.” By S. U. Pickering. BARBISON AND SONb, PlllSiTElZE IN OBUINAEY TJ lihX MAJESTY, ST MARTIN’S LALYE.
ISSN:0369-8718
DOI:10.1039/PL8870300063
出版商:RSC
年代:1887
数据来源: RSC
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