Si On the Composition of [July, 



the surface, form a great current at least two fathoms in circum- 

 ference. On the 23d of September, 1810, the thermometer placed 

 in it stood at 44-06°. 



As experience has now shown that the colder springs flow near 

 the surface of the earth, I think myself entitled to infer from my 

 observations, continued during several years, that 43-/0° is very 

 nearly the true mean temperature of the earth at Upsala. 



{To be continued.) 



Article V. 



New Ohservatiojis on the Composition of Alcohol and Sulphuric 

 Ether. Presented to the French Institute by M. Theodore de 

 Saussure.* 



1. The experiments which I published some years ago on 

 alcohol and sulphuric ether \ were sufficient to show that ether 

 contains more carbon and hydrogen than alcohol ; but they were 

 far from showing the true proportion of the elements of these two 

 liquids. I took care to announce that these first results were mere 

 approximations, and contained only the rudiments of a set of expe- 

 riments which would he resumed and completed. 



A great simplification of the means which I formerly employed 

 for the analysis of ether, some improvements in the eudiometrical 

 processes, and some corrections in the data from which these 

 analyses are calculated, enable me at present to lay before the 

 puhlic much more correct results. 



The methods of analysing vegetable substances have not yet 

 reached that precision which is exhibited in the analysis of different 

 mineral substances. Such extreme accuracy would in all probability 

 be useless if applied to bodies like alcohol and ether, the degree of 

 purity of which is not yet ascertained : but we shall find that these 

 two liquids have a property which determines with precision the 

 manner of their composition. 



The data which serve as the basis of my calculations are the spe- 

 cific gravities of the gases as determined by Biot and Arago, the 

 weight of the cubic decimetre (61 "028 cubic inches) of atmospheric 

 air being 1*293 gramme (19-969 grains troy), at the temperature 

 of 32°, when the barometer stands at 29"922 inches, and when the 

 hygrometer marks extreme dryness.]: I admit that in these circum- 

 stances the cubic decimetre of carbonic acid gas contains 05378 

 gramme (8-306 grains troy) of carbon, and that 100 parts by weight 



• Translated from the Bibliotheque Britannique, vol. liv. No. iv. Dec. 1813. 

 + Jour, de Phys. t. lxir. 



J This would make the weight of 100 cubic inches of drj air, at the tempera- 

 ture of 60% 30-904 grains troy, which I believe about 0-404 grain too high. — T. 



