ANNALS 



OF 



PHILOSOPHY. 



AUGUST, 1820. 



Article I. 



HISTORICAL SKETCH OF IMPROVEMENTS IN PHYSICAL 

 SCIENCE DURING THE YEAR 1819. 



1. The Chemical Sciences. By Thomas Thomson, M.D. F.R.S. 



{Concluded from p. 46.) 



X. Compound Combustibles. 



1. Sulphuric Ether.— Mv. Dalton has pubUshed an interesting 

 paper on sulphuric ether, which I have inserted in the Annals of 

 Philosophy, xv. 117. He gives us some information respecting 

 its manufacture, and makes some inferences respecting its 

 purity. Had he taken the trouble to consult the section on 

 sulphuric ether in my System of Chemistry, vol. ii. p. 331, he 

 would have seen that the specific gravity of pure sulphuric ether 

 is only 0-632 instead of 0-720, as he supposes it to be. He 

 would have seen too in p. 332 of the same volume that the spe- 

 cific gravity of the vapour of sulphuric ether is not 3'2, as he has 

 made it by a set of experiments not susceptible of much preci- 

 sion, though exceedingly ingenious, but 2-586 — determined by 

 Gay-Lussac by a much more perfect apparatus. 



The experiments which Mr. Dalton has made on the analysis 

 of ether show in a very satisfactory manner that the notion 

 which I threw out in my System of Chemistry, that sulphuric 

 ether is a compound of two atoms defiant gas and one atom vapour 

 of water condensed into one volume, is the true one ; for the 

 proportion of oxygen necessary to consume a given volume of 



Vol. XVI. N° II. - F 



