yan. 13, 1 88 1 ] 



NA TURE 



245 



Hofmann as non-resident Assayer to the Royal Mint, but 

 was deprived of the appointment by Mr. R. Lowe, who 

 abolished the office in 1870. 



A pupil of Graham and Liebig, he had all their en- 

 thusiasm for scientific investigation, and devoted nearly 

 the whole of his time to research work in the domain of 

 organic chemistry : the eminence he attained in this 

 branch of science is fully recognised, but his contribu- 

 tions to our technical knowledge are not so well known. 

 He was the author of many ingenious and useful inven- 

 tions in relation to dyeing, sugar manufacture, tanning, 

 &c., but the greatest and most permanent has been the 

 application of charcoal for disinfecting and deodorising 

 purposes, which took the form of charcoal air-filters for 

 the ventilation of sewers, and the charcoal respirator, 

 the best of all re jpirators, not only for preventing the 

 deleterious effects of noxious gases in numerous manu- 

 facturing operations, but also for the protection of 

 those subject to bronchitis, asthma, and other similar 

 diseases. 



It is impossible in our limited space to give even an 

 outline of the numerous investigations which he published 

 during his long scientific career, extending as it did over 

 a space of more than forty years. The results are em- 

 bodied in about 100 papers, published in various scientific 

 journals, English and foreign ; they relate in great part to 

 what may truly be called " organic chemistry " — the che- 

 mistry of carbon co.npounds formed by organised bodies. 

 John Stenhouse was LL.D. of Aberdeen; a Fellow of 

 the Royal Society, which awarded him the Royal Medal 

 in 1S71 ; one of the founders of the Cheaiical Society ; 

 and a Fellow of the recently-established Institute of Che- 

 iriistry. Uf his personal character those who knew him 

 intimately could never speak too highly ; his death 

 will be felt and mourned not only by his many per- 

 sonal friends, but also by men of science throughout 

 Eurjpe. 



WILHELM HEINTZ 



A X/'E recently recorded the death, at H tile, on December 

 ' • I, of Prof. W. Heintz, one of the leading German 

 chemists of our day. He was born at Berlin, November 4, 

 1817. His earlier university studies were undertaken 

 with a view of becoming a pharmacist, but this intention 

 was relinquished as the attractions of a more purely 

 scientific career were offered to him. In 1844 he received 

 the doctor's degree at the Berlin University, and two 

 years later he was admitted as privat-docent in the philo- 

 sophical faculty of the same university. In 1850 he 

 accepted a call to Halle as the successor of the well- 

 known Marschand ; and here, after passing five years as 

 an extraordmary professor, he was appointed in 1855 to 

 the full professorship of chemistry, and the directorship 

 of the newly-built laboratory, posts which he occupied at 

 the time of his death. 



As a teacher and as a guide to students inclined towards 

 chemical research. Prof. Heintz evinced more than 

 ordinary capacity, and for a quarter of a century he has 

 ably maintained the reputation of Halle among the centres 

 of chemical interest in Germany. This reputation is due 

 in no small part to his own personal contributions as an 

 investigator; for few chemists of our d ly have manifested 

 such unwearied energy and long-continued application, 

 ■such thoroughness of work, a:curacy of observation, and 

 widespread familiarity with fact and theory as are evinced 

 in Heintz's manifold and diversified researches. 



The earlier portion of his career was directed to the 

 solution of problems in physiological chemistry. Among 

 his more important researches in this direction mention 

 should be made of those on the juice of the Galacto- 

 dciidron (1845), on kreatin and kreatinin (1847), on lactic 

 acid in the gastric juice (1S49), on the composition of 



bones, and on cholesterin (1850), on the colouring matter 

 of gall stones (1851), on urinary sediments (1862), and 

 more especially on the animal and vegetable fats. This 

 latter research, extending over a period of about seven 

 years, includes exhaustive studies on the physical pro- 

 perties of the fats, methods of tbeir separation, their 

 chemical constitution and nature, the products of their 

 decomposition, &c. His careful observations of the 

 melting points and composition of the fatty acids in the 

 pure state and when mixed with each other, form essen- 

 tially the basis of our present knowledge on this subject, 

 and enabled him at the time to show the composite 

 character of various fats which preceding chemists had 

 regarded as pure compounds. 



In analytical chemistry Heintz devised a variety of 

 methods and modifications of methods, amongst which 

 mention may be made of his contributions on the esti- 

 mation of sulphur in organic bodies, on the separation of 

 magnesia from the alkalies, on the analysis of ashes 

 (1847), on the determination of urea and uric acid, on 

 the detection of gall (1S48), on the determination of 

 nitrogen (185 i), on the estimation of phosphoric acid, and 

 numerous analytical data. 



In inorganic chemistry his researches were chiefly con- 

 fined to studies on a variety of phosphates, on bismuth 

 and uranium salts, on the preparation of caesium and 

 rubidium compounds (1865), on the combustion of am- 

 monia in oxygen (1864), on the silicates of the alka- 

 line metals, and to the examination of the minerals 

 margarite, stassfurtite, carnallite, aluminite, and boracite, 

 the latter of which he prepared artificially (i860). 



It is however in the field of pure organic chemistry 

 that Heintz's discoveries have been most numerous and 

 important. They commence with his investigation on 

 saccharic acid, begun in 1844 and resumed in 1858-1860, 

 to which we owe a great measure of our knowledge of 

 this acid, and especially of its salts and ethers. This 

 was followed in 1856 by a study on the action of chloride 

 of sulphur on the salts of organic acids, in which he 

 recorded the unvarying and simultaneous formation of 

 chlorides and sulphates at the expense of the organic 

 salts. In 1859 he began his extensive research on glycoUic 

 acid, which occupied much of his time untd 1872, by 

 exposing mono;hloracetic a?id to the action of various 

 sodium alcoholates, obtaining thereby the different ethers 

 of glycollic acid ; thus with sodium ethylate : 



CH^.OCjH^ 



CH.,Cl.COOH+NaOC.,H5 = NaCl-t- I 



COOH 

 By means of this prolific reaction he obtained a number 

 of interesting derivatives of the acid in question. Closely 

 allied to them were the acid ethers of glycollic acid, 

 obtained by submitting mono -hloracetic ethers to the action 

 of salts, or by acting upon glycollic ethers with such 

 bodies as phosgene or chlorocarbonic ether. Among 

 the other important compounds discovered by him in 

 this group are glycolami ie, glycol-ethyl-amide, digly- 

 collic acid — 0(CH2 . COOH).,— obtained by the action of 

 sodium hydrate on monochloracetic acid, diglycoU-dia- 

 mide, diglycoUamic acid, &c. During this same period 

 he made noteworthy investigations on the ethyl-aminss, 

 on sulphocyan-aceti; a;id and its derivatives, on nitrate 

 of ethyl, on ethyl-hydanto'i'n, on lactic acids, and on 

 the amido-acids obtained from chloropropionic and iodo- 

 propionic acids by the action of ammonia. With 1874 

 commences his last important research — that on the 

 aceton bases, the simplest of which result from the action 

 of ammonia on aceton. While forced to overcome mani- 

 fold difficulties in the prosecution of this investiga- 

 tion, Heintz succeeded in isolating a number of novel 

 and important compounds, especially interesting from a 

 theoretical point of view. The leading forms embraced 

 in this new group are diacetonimine, triacetonamine ; 

 the corresponding alcohol bases dia -eton-alcamine and 



