76 



NATURE 



{May 25, 1876 



Nitroxide of Amylen, — Discovered by the exhibitor. 

 Of historical interest as being the first instance in which 

 nitroxyl NO^ was shown to behave as a halogen in 

 uniting directly with an olefine to form a body homologous 

 with " Dutch liquid." The composition of the body is 

 QHio(N02)2. 



Sulphide of Qinanthyl. — Discovered by the exhibitor, 

 and of historical interest as being the first instance in 

 which a term of a higher alcohol series was made from 

 terms of lower alcohols. It is formed by the action of 

 zinc ethyl on sulpho-chloride of amylen. 



And Nitrate of Amyl. — Discovered by M. Balard. Its 

 therapeutic action was discovered, and its introduction 

 into the pharmacopoeia recommended, by the exhibitor ; 

 and it is now coming into use in tetanic and other nervous 

 affections. 



A series of twenty-three specimens of hydrocarbons 

 derived from Pennsylvanian petroleum is exhibited by 

 Prof. Schorlemmer. They form a striking record of the 

 skill with which a most laborious and difficult investigation 

 has been conducted. 



Very interesting and important arc the ethyl com- 

 pounds derived from the isolated radical methyl exhibited 

 by Mr. W. H. Darling. The results of some experiments 

 made by myself seemed to indicate that the products 

 of the action of chlorine upon methyl were not ethyl 

 compounds ; but the experiments of Schorlemmer and 

 Darling conducted with much larger quantities of mate- 

 rial, show that my conclusion was erroneous. Mr. Darling 

 exhibits ethylic chloride, ethylic alcohol, ethylidenic chlo- 

 ride and sodic acetate, all made from electrolytic methyl. 



Mr. Perkin has sent a large collection of specimens 

 illustrating his researches on mauveine, aitificial alizarin, 

 artificial coumarin, glyoxylic acid, and other subjects. 

 His investigation of glyoxylic acid seems to have at last 

 put an end to the controversy as to the possibility of two 

 semimolecules of hydroxyl being united with one and the 

 same atom of carbon. I will not, however, anticipate 

 Mr. Perkin, who will, I trust, personally give us an account 

 of his researches. 



Amongst the other exhibits in this department are nume- 

 rous and important contributions from the laboratories 

 of St. Petersburg, Louvain and Edinburgh. For several 

 years past chemical research has been actively carried 

 on in Russia. 



The apparatus usedin Research exhibited in the Chemical 

 Section has suffered much from the depredations of the 

 physicists, for although chemistry is essentially founded 

 upon measurements of weight and volume, the instruments 

 used for such determinations have been swept almost en 

 masse into the section of measurement ; nevertheless, the 

 chemical section contains several objects of unusual in- 

 terest. The apparatus with which chemists, both ancient 

 and modern, prosecuted their researches was generally of a 

 simple description and often dismantled as soon as the 

 necessary operations were completed, consequently it was 

 far less likely to be preserved than the more expensive and 

 elaborate contrivances of the physicist. Here, however, 

 is Black's balance presented to the Science and Art 

 Museum of Edinburgh, by the Right Hon. Lyon Playfair. 

 Upon this balance Dr. Black ascertained in 1757, the loss 

 of weight suffered by carbonate of magnesia and lime- 

 stone when exposed to heat. Hales previously used a 

 balance for this purpose, but the instrument before us was 

 certainly one of the first employed for quantitative chemis- 

 try. The balances used by Cavendish, Davy, Young, and 

 Dalton are here, and each one of them has its own 

 historical interest for the chemist The balance of 

 Cavendish is probably the instrument with which in 1783 

 or 1784 he first ascertained that a globe filled with a mix- 

 ture of oxygen and hydrogen gases underwent no altera- 

 tion in weight when the mixture was exploded. 



From gravimetric instruments we are naturally led to 

 volumetric apparatus used in quantitative chemistry, and 



I will now, in conclusion, briefly direct the attention of 

 the conference to apparatus used in the analysis of gases, 

 in the hope that a discussion of the merits and defects of 

 the numerous instruments now before me may have the 

 effect of directing a larger share of attention to eudio- 

 metric chemistry than has hitherto been accorded to it. 

 This branch of chemical analysis originated in the attempts 

 of Fontana, Landriani, Scheele, Priestley, Cavendish, Gay 

 Lussac, Dalton, and others, to determine the volume of 

 oxygen in samples of atmospheric air taken from various 

 localities. In these primitive instruments air was exposed 

 to the action of some substance either solid, liquid, or 

 gaseous, which combined with the oxygen and left the 

 nitrogen unacted upon. The chief substances used were 

 phosphorus, potassic sulphide, nitric oxide, a solution of 

 nitric oxide in ferrous sulphate, and a mixture of sulphur 

 and iron filings. Many of the instruments were of simple 

 or even rude construction, and little calculated to inspire 

 confidence in the results. Nevertheless, the accuracy cf 

 a determination often depends much more upon the skill 

 of the operator than upon the construction of the instru- 

 ment used ; and thus Cavendish, with nitric oxide as his 

 reagent and water as the confining liquid, made many 

 hundred analyses of air, collected in various localities, in 

 1781, and found the percentage of oxygen to be invariably 

 2083, a number nearly identical with those obtained by 

 Bunsen and Regnault with much more perfect means. But 

 the average chemist of that day obtained the most dis- 

 cordant results with the same apparatus and materials, 

 and would doubtless also do so at the present day. By 

 improved apparatus and methods the work of the average 

 chemist is made to equal, or nearly so, that of the most 

 skilful. 



Volta introduced a new reagent — hydrogen — for the 

 determination of oxygen, and he was the first to employ 

 the electric spark in eudiometry. The use of mercury 

 instead of water for confining the gases eliminated, the 

 source of fallacy caused by transfusion through the 

 latter liquid, and lastly, Bunsen, in the year 1839, brought 

 Volta's eudiometer to its highest degree of perfection. 



The President then proceeded to describe and criticise 

 the various forms of apparatus for the analysis of gaseous 

 mixtures, and poncluded as follows : — 



Such are the modern developments of the eudiometer 

 now at the disposal of chemists. For rapidity of working 

 and delicacy of measurement they leave nothing to be 

 desired ; indeed, as regards delicacy, it may be doubted 

 whether amongst all the instruments for measurement in 

 this exhibition, there is one which can, like some of these 

 eudiometers, give a distinct value in weight or volume to 

 the one-fourteen-millionth part of a gramme of matter. 

 Their drawback is their fragility, and any modifications 

 to diminish this would doubtless be welcomed by 

 chemists, since, chiefly for these reasons, eudiometry is 

 still very rarely practised in chemical laboratories. 



THE PRESS ON THE LOAN COLLECTION 



T N continuation of our article in last week's number we 

 ■*• proceed to give a few more selections from the prin- 

 cipal organs of public opinion, indicative of the light in 

 which they regard the scientific collection which has been 

 brought together at South Kensington. Last week we 

 confined ourselves mainly to the daily press ; this week we 

 are able to cull the opinions of the principal weekly papers. 

 Public opinion as thus expressed, it will be seen, all but 

 unanimously approves of the collection as creditable to 

 its organizers and to the country at large, as beneficial to 

 the progress of science, and as calculated to have an im- 

 portant educative influence on the British pubUc. We 

 think the collection of public opinion as thus expressed 

 will serve a good purpose. It will show to those men of 

 science whp h^v? be?ji more or less connected with the 



