62 



NATURE 



{Nov. 21, 1878 



what they can to guard themselves against it. They begin to 

 purify their houses by lighting fires in every room, and in 

 certain towns they alistain from pork. Mr. Rocher gives 

 details as to the symptoms and courfc of the disease, 

 "With regard to the track of the epidemic Mr. Rocher observed 

 a peculiar fact both in the north and south of the province. 

 Instead of visiting every village in its direct line of progress it 

 would pass some completely by, visiting places near them and 

 on both sides, to return to those forgotten spots several months 

 afterwards, when the epidemic would appear to have passed far 

 away. Another fact not less curious is that after having appeared 

 in almost every one of the villages scattered about the plains, 

 it frequently ascends the mountains, where, among the abo- 

 rigines who inhabit the high lands, it claims many victims. We 

 may add that Mr. Rocher's notes are accompanied by a map, 

 compiled from private and official memoranda, which shows the 

 course followed by the plague in 1871, 72, and 73 ; it was not 

 possible, however, to include in it the towns in the west of the 

 province, which was at that time the theatre of the war between 

 the Imperialists and the Mahometan rebels, as the information 

 obtainable was quite untmstworthy, but it is certain that the 

 epidemic was constantly present among the Imperialist troops. 



The additions to the Zoological Society's Gardens during the 

 past week include a Green Monkey {Cercopithecus callttrichus) 

 from West Africa, presented by Miss G. E. Marryat ; a Bonnet 

 Monkey (^Macacus radiatus) from India, presented by Mr. F, 

 Hinde ; two Horsfield's Tortoises (Testudo horsfieldt) from 

 Turkestan, presented by Dr. Alex. Strauch, C.M.Z.S. ; a 

 Wanderoo Monkey {Macacus siltitus) from Malabar, two 

 Egyptian Jerboas {Dipus crgyptius) from Egypt, a Sun Bittern 

 (Eurypyga helias) from South America, deposited j a Woodcock 

 {Scolopax rusiicola), European, purchased. 



CHARLES ADOLPHE WURTZ 



IN connection with the Faraday Lecture which follows, 

 it may interest our readers to have a few particulars 

 as to the life and work of the lecturer, Prof. Wurtz. 



Charles Adolphe Wurtz was born at Strassburg on 

 November 16, 1817. He commenced his chemical career 

 as assistant to Dumas, and first acquired an independent 

 position as professor at the Agricultural Institute at 

 Versailles. For the last thirty , years he has been 

 Professor of Chemistry at the Ecole de M^decine, 

 Paris ; in addition to which he now holds the post of 

 Professor of Chemistry at the Sorbonne. 



Prof. Wurtz is a m.ember of the Institute (Acaddmie des 

 Sciences), and a foreign Fellow of the Royal Society. 



Some idea of the energy which he has displayed as an 

 investigator is conveyed by the fact that a list of no less 

 than seventy-three titles of papers is appended to his 

 name in the Royal Society Catalogue, which only includes 

 papers published previous to 1864. Much of his work is 

 of the first importance in connection with chemical theory, 

 and he undoubtedly takes rank as one of the chief pio- 

 neers of modem organic chemistry. 



His first investigation, pubhshed in 1842, was on the 

 constitution of the hypophosphites ; this was followed by 

 researches on phosphorous acid, sulpho-phosphoric acid, 

 &c., which greatly added to our knowledge of the phos- 

 phorus compounds. It was in the course of his experi- 

 ments on the hypophosphites that Wurtz discovered 

 hydride of copper, CujHs, one of the most remarkable 

 hydrides with which we are acquainted, and especially 

 interesting as, with the exception of potassium, sodium, 

 and perhaps palladium, none of the metals appear to be 

 capable of combining with hydrogen. Hydride of cop- 

 per is formed as a yellowish precipitate on adding a 

 concentrated solution of copper sulphate to a solution of 

 hypophosphorous acid, and warming the mixture to about 



70" C. ; in the dry state it slowly decomposes into its 

 constituents at about 55" C. ; concentrated hydrochloric 

 acid at once dissolves it with evolution of hydrogen, 

 although copper is not in the least aflfected by this acid, 

 and what is most remarkable, both the hydrogen of the 

 acid and of the hydride of copper are given off as shown 

 by the equation — 



CU2H2 + 2HCI = CU2CI2 + 2H2. 



The study of certain cyanogen compounds — the cyanic 

 and cyanuric ethers — next engaged his attention, and 

 his researches on these bodies culminated in the remark- 

 able discovery, in 1849, of the so-called compound 

 ammonias formed by the displacement of one of the 

 atoms of hydrogen in ammonia, NH3, by organic radicles, 

 such as methyl, CH3, ethyl, CjHg, &c. 



A third investigation to which we may here refer is 

 that on the alcohol radicles published in 1855. Frank- 

 land had shown that the hydrocarbon radicles which it 

 was assumed were contained in the alcohols could 

 actually be isolated ; that, from ordinary or ethyl acohol, 

 for example, which may be regarded as a compound of 

 the radicle ethyl, C2H5, with the radicle OH, we may 

 obtain ethyl by acting with zinc on the iodide which it 

 yields on treatment with hydriodic acid, thus withdraw- 

 ing the iodine from it, just as the iodine is withdrawn 

 from the hydrogen in hydriodic acid by the action of 

 metals ; and Kolbe had obtained similar results with acids, 

 such as acetic acid, by submitting solutions of their salts to 

 the action of a powerful electric current. These chemists, 

 however, supposed that the radicles thus withdrawn from 

 combination with other radicles remained in the free state, 

 but Laurent and Gerhardt, and Hofmann argued on 

 theoretical grounds that the bodies thus produced Avere 

 not the radicles themselves but compounds of the radicles 

 with themselves — that ethyl, for example, was not C2HS, 

 but C4H10 or C2H5 + C2H5. Conclusive evidence of the 

 correctness of this latter view was afforded by Wurtz's 

 discovery that if a mixture of the iodides of two different 

 radicles were treated with metaUic sodium, a hydrocarbon 

 formed by the union of the two different radicles was 

 obtained. This discovery has afforded one of the chief 

 arguments in favour of the view now almost universally 

 entertained by chemists, that free hydrogen is a compound 

 of hydrogen with hydrogen. 



The mere recapitulation of the titles of his remaining 

 investigations would alone occupy a large amount of 

 space. We can only refer to those on the glycols and 

 on ethylene oxide ; on the action of nascent hydrogen 

 on aldehyde ; on the action of chlorine on aldehyde, both 

 in the anhydrous state and in presence of water ; on the 

 action of hydrochloric acid on aldehyde ; on the syn- 

 thesis of neurine ; and on abnormal vapour densities, 

 as being, among others, of especial interest. 



ON THE CONSTITUTION OF MATTER IN. 

 THE GASEOUS STATE'^ 



Ladies and Gentlemen, — 



I ESTEEM it a great honour to address you within these walls, 

 about which there still hovers the ever fresh memory of him 

 whose name we celebrate to-day, while we deplore his loss. I 

 am fully sensible both of the great value of this honour and of 

 the danger that attends it, and I have need to shelter myself 

 under the authority of the great name of Faraday. I have, 

 therefore, chosen a subject connected with his earliest dis- 

 coveries. The constitution of matter is a question of the highest 

 importance with regard both to physics and to chemistry. 



The word " gas " was introduced into science by Van Helmont, 

 who, at the beginning of the seventeenth century, first pointed 

 out, with some degree of precision, the differences existing be- 



' The Faraday lecture, delivered before the Fellows of the Chemical 

 Society, in the Theatre of the Royal Institution, on Tuesday, November 12,^ 

 1878, by Ad. Wurtz, Membrede I'Inbtitut ; Doyen Honoraire de la I'aculte 

 de Medecine de Paris. 



