Results of the Labours of Continental Chemists. 203 



idea, not of what has been done, but merely of what is ac- 

 tually going on in the Continental chemical world. 



Should our attempt meet your approval and that of your 

 readers, we shall with pleasure continue our communication 

 monthly. We have the honour to remain, 



Dear Sir, yours truly, 



William Francis. 

 Berlin, Dec. 13,1840. Henry Croft. 



P.S. The Journals consulted are Poggendorff s Annalen der Physilc und 

 Chemie ; Liebig's Annalen der Cheniie und Pkarmacie ; Erdmann's Journal 

 tur Praldische Chemie ; Archiv der Pkarmacie ; Annalen de Chimie et de 

 Phyaique; Journal de Pkarmacie; Berzelius's Amberattelse, and the 

 German translation by Wbhler. 



MM. Dumas and Stas have published a second treatise 

 on chemical types *. The principal subject of this treatise 

 is the action of potassa on the various kinds of alcohol, 

 both those which are evidently similar to the wine alco- 

 hol, and also on those substances which have been consi- 

 dered as analogous to alcohol, as for instance, glycerin, &c. 

 In many cases it is possible to convert an alcohol into its 

 equivalent acid ; but yet chemists have not been able to con- 

 vert an acid into its corresponding alcohol. The discovery 

 and examination of these alcohols is much more important 

 than that of any acid ; for the acid is only interesting in as 

 far as its combinations with inorganic bases are concerned, 

 while an alcohol is the head of a numerous family. A new 

 alcohol may be compared to a new metal. The formula of 

 the alcohol of any acid is found by substituting H^ for O^ in 

 the hydrated acid. 



In the experiments on the action of hydrate of potassa, it 

 was found convenient to employ a mixture of equal parts of 

 fused potassa and well-burnt lime. This substance affected 

 the glass vessel? much less than potassa alone ; it may, for 

 shortness' sake, be called lime-potassa. 



If this substance be moistened with alcohol and subjected 

 to a gentle heat, a gas is developed which consists chiefly of 

 hydrogen, and a little carburetted hydrogen and carbonic 

 oxide. The residue contained a quantity of acetic acid, pro- 

 portional to the quantity of alcohol employed. If the heat is 

 increased, carbonate of potassa remains behind, and marsh 

 gas (light carburetted hydrogen) is given off; for under the 

 influence of alkalies, acetic acid is decomposed into carbonic 

 acid and marsh gas, O H' O^ = C' O* + C^ 11^ In the 

 usual preparation of acetic acid, two atoms of hydrogen are 



• Annalen der Ckeniic und Pkarmacie, xxxv. p. 129, from Annates de 

 Chimie et de Pht/sique, vol. Ixvi. p. 113. 



