Thomson's Sj/s/em of Cheiiiiatri). IGI 



In treating of sulplmric ether, he gives the atomic view of 

 its constitution, as if deduced by himself, from Mr. Dalton's 

 experiments ; but M. Gay-Lussac is the sole author of that 

 important demonstration. ' If we turn to the Annales de Chimie, 

 Tom. 95, for July, 1815, we find the following statement, " M. 

 Gay-Lussac, pense que I'analyse de I'ether sulfurique, par M. 

 de Saussure, n'est point f;xacte. II croit que cet ether est 

 compose de deux volumes de gas hydrogene percarbone (olefiant 

 gas) et d'un volume de vapeur d'eau, ou en poids de 100 d'hy- 

 drogcne percarbone, et de 31.95 d'eau, parce qu'en efFet, en 

 ajoutant deux fois la densite de gas hydrogene percarbone a 

 celle de la vapeur d'eau, c'est a dire 0.978, phis 0.978 a 0.625, 

 on obtient 2.581, qui ne diftere que de 5 miUiemes de 2.586, 

 densite de la vapeur d'ether. Cette vapeur resulterait done de 

 deux volumes de gas hydrogene percarbone, et d'un volume de 

 vapeur d'eau condensees en un seul *." Yet our author claims 

 for himself, in 1817, the merit of a research published by M. 

 Gay-Lussac in 1815, and reprinted with just commendations by 

 M. Thenard in 1816? " The experiments," says the Doctor, 

 " which Mr. Dalton has made on the analysis of ether, shew 

 in a very satisfactory manner, that the notion which / threw 

 out in my Si/sta>i of Chemistry (of 1817), that sulphuric ether 

 is a compound of two atoms olefiant gas, and one atom 

 vapour of water, condensed into one volume, is the true one." 

 " Hence 



2 volumes olefiant gas weigh 1. 94 1 6 



1 volume vapour of water 0.625 



Total 2^66^^ 



Specific gravity of other vapour is ... . 2.5860t" 

 In treating of muriatic ether, he quotes M. Thenard's experi- 

 ments from the Manoires d'Arcueil, Tome I, published in 1 807 ; 

 but entirely conceals the more recent researches of M. M. Colin 

 and Robiquet in the Annales de Chimie et de Physicpie, I., p. 348, 

 published in April 1816, where they shew that, this ether passed 

 through an ignited tube is converted into muriatic acid and 

 carburetted hydrogen, and that its constitution may be repre- 

 sented by 1 volume of olefiant gas -1- 1 volume of muriatic 

 acid, condensed into one volume ; for the sum of the densities of 

 these gases, is nearly the same with the density of muriatic ether 

 vapour. The Doctor sinks all this from abroad, and brings the 

 view forward, as if this idea of its constitution, were a sugges- 

 tion of his own. " I have very little doubt," says he, " that 

 this ether is a compound of 1 volume of olefiant gas + 1 volume 

 muriatic acid gas, condensed into one volume. On this suppo- 



• We print the above passage, as it is quoted by M. Thenard, in hit 

 Tiaili, Tom. IV., )). 'i3;K published in IBIO", to shew the ■general promul- 

 gation of this view of ctlier, h)nf; prior to the Doctor's .5th Edition. 



t Thomson, in /hinah of PkUomiihy, August, IbaO, p. 81. 



Vol. XL M 



