248 



NA TURE 



[January 12, 1893 



CHEMICAL SOCIETY'S MEMORIAL 

 LECTURES. 



AT an extra meeting of the Chemical Society, held on 

 December 13 last, this being the first anniversary 

 of the death of Stas, a paper was read and discussed 

 which had been prepared for the occasion by Prof. J. W. 

 Mallet, F.R.S., of the University of Virginia, U.S.N.A. 

 —himself a high authority on atomic weight determina- 

 tions, and well known to chemists through his papers on 

 the atomic weights of aluminium and gold, published by 

 the Royal Society of London. 



The lecture marks a new departure in the work of the 

 society. Hitherto our learned societies have been in the 

 habit of publishing more or less complete— it would 

 probably be nearer the truth to say incomplete — obituary 

 notices of their foreign members. The Chemical Society 

 has come to the conclusion, however, that inasmuch as 

 its foreign members are always men of great distinction 

 who, as a rule, have lived a considerable number of years 

 after accomplishing their life work, it will be to the ad- 

 vantage of its fellows and of chemists generally, if the 

 obituary notices of foreign members take the form of 

 critical monographs of the subjects with which they have 

 principally dealt. 



The anniversary of the death of the foreign member 

 is obviously the most appropriate occasion for the de- 

 livery of such a lecture. During the past year the society 

 has lost two of its foreign members : Hermann Kopp, 

 noted as an historian, as well as on account of his very 

 numerous exact determinations of atomic volumes and 

 specific heats, and A. W. von Hofmann. The life and 

 work of the first mentioned will form the subject of a 

 lecture to be delivered on February 20 next, by Prof. 

 Thorpe, the Treasurer of the Society, than whom no one 

 is more qualified to undertake the task. Prof. Thorpe is 

 not only a pupil of the deceased chemist, but has rever- 

 ently followed in his footsteps — having very largely 

 extended Kopp's observations on atomic volumes in an 

 elaborate investigation, the importance of which was 

 recognised by the Chemical Society in 1881 through the 

 award to him of its first Longstaff medal. 



Von Hofmann, although originally a foreign member, 

 became an ordinary member of the Chemical Society on 

 coming to England as professor at the school in Oxford 

 Street, long since merged in what is now known as the 

 Royal College of Science, London. Hofmann was never 

 again regarded as a foreigner; he served the society 

 both as foreign secretary and as president, filling one of 

 the vice-chairs during the remainder of his life. It is 

 felt that owing to the special nature of his relations to the 

 society and to english chemistry, it will be necessary to 

 deal with his case in an exceptional manner ; it is there- 

 fore hoped that in May next Lord Playfair — who was so 

 intimately connected in his early days with chemical 

 science and with the society — in the first place will pic- 

 ture the state of affairs chemical at and prior to the 

 time of Hofmann's arrival in England. Sir F. Abel, 

 Hofmann's first pupil and assistant, will follow with an 

 account of Hofmann at the Royal College of Chemistry, 

 calling to his aid for this purpose the remaining friends 

 and pupils of Hofmann. The coal-tar colour industry, 

 which has now attained such important dimensions, it is 

 well known, had its origin in the Oxford Street laboratory, 

 and Dr. Perkin —its parent — has consented to sketch the 

 history of its development. In this manner it is hoped 

 to impart considerable " local colour " to the Hofmann 

 memorial lecture, thereby distinguishing it from the 

 notice which is being prepared by the German bio- 

 graphers. 



Passing now to Prof. Mallet's lecture on Stas, which is 

 of considerable length, as it will occupy fully sixty pages 

 in the Society's Journal. The biographical portion is 

 brief, as a number of such sketches have already been 



NO. 121 I. VOL. 47] 



published. Stas was bom at Louvain on August 21, 181 3. 

 He graduated as Doctor of Medicine. His taste for 

 chemical research was evidenced in 1835, when, together 

 with a friend, he investigated in an attic of his father's 

 house the crystalline substance phloridzin which they had 

 extracted from the root bark of the apple tree. He con- 

 tinued the study of this substance in Dumas' laboratory 

 in Paris, and it is an interesting proof of the acumen of 

 Berzelius that in his annual report on the progress of 

 chemistry he referred to this first research made by Stas 

 with praise, and a prediction of future eminence for the 

 author. 



The startin'g-point of the long train of research with 

 which his name will ever be associated was the redeter- 

 mination of the atomic mass of carbon which Dumas and 

 he together undertook, in order to explain the fact, 

 noticed by Liebig and others, that the sum of the carbon 

 and hydrogen found in hydrocarbons by the combustion 

 process, as calculated from the carbon dioxide and water, 

 not unfrequently exceeded the quantity of material ana- 

 lyzed. As the result of this investigation, which was 

 carried out with unprecedented care and the most ela- 

 borate precautions, the value hitherto accepted for carbon 

 on the authority of Berzelius (76432 = ioo) was con- 

 siderably reduced (to 75'oo5). In 1840 Stas was appointed 

 Professor in the Ecole Royale Militaire at Brussels ; he 

 held this post for more than a quarter of a century, until 

 an affection of the bronchial tubes and larynx obliged 

 him to give up lecturing. He then received an appoint- 

 ment in the Mint, but resigned this in 1872 on political 

 grounds, and withdrew into private life. He appears 

 to have been a man of great independence of character. 



Apart from his atomic weight investigations Stas did 

 much work of value in other departments. His method 

 of separating alkaloids from organic messes — no other 

 name is applicable — which has been of such service in 

 subsequent toxicological inquiries, was devised in 1850,. 

 in the course of the inquiry into the celebrated Bocarm^ 

 nicotine poisoning case. He examined into the methods of 

 hydrolysing fats for the purpose of a report on the 

 chemical section of the London 1862 Exhibition. In con- 

 nection with the preparation of international standards 

 he took an active part, along with Devile, in the inquiry 

 into the properties of the platinum metals. It is known 

 also that he did important work for his Government in 

 investigating alloys for use in the construction of artillery. 



Prof. Mallet prefaces his account of Stas's special in- 

 vestigations by an historical survey of the fundamental 

 ideas which have gradually led up to the question, What 

 is the mass of an atom of a particular element ? Even 

 in and beyond the days of Cavendish and Priestley the 

 fact that atmospheric air was found of constant or nearly 

 constant composition was long a stumbling-block in the 

 way of clear distinction between a homogeneous com- 

 pound and a uniform mixture. To the labours of Van 

 Helmont, Boyle, and Boerhave much credit is due for the 

 gradual advance towards the doctrine of the conservation 

 of matter. The discoveries of Black and Cavendish 

 brought it further into view, and it assumed its due import- 

 ance and began to receive universal recognition with the 

 constant appeal to the balance which Lavoisier made and 

 taught others to make. Next came a comparison of the 

 quantities of different substances, at first chiefly the then 

 known acids and bases, which would enter into combina- 

 tion with each other. Proust, in the course of his con- 

 troversy with Berthollet as to the fixedness of combining 

 proportions, had observed that in certain cases it was true 

 that in different compounds, consisting of the same con- 

 stituents, for a fixed quantity of one constituent, the 

 different quantities of another constituent bear to each 

 other a simple multiple or sub-multiple relation. To 

 Dalton, however, belongs the honour of announcing the 

 principle as a general one, and of basing upon it a true 

 chemical atomic theory of the nature of matter. Berzelius,. 



