of Fyroxylk Spirit^ and of its derived Covibinations, 1 1 9 



spirit, bearing the same relation to the methylene that acetic 

 acid bears to the alcohol series. In fact, the fluid under exa- 

 mination is the acetai of the methylene series, and is formed 

 under perfectly similar circumstances; the pyroxylic spirit is 

 by the sul{)huric acid converted into methylene aether, and 

 i atoms methylene aether = Cg H24 O4 

 lose 4 atoms of hydrogen — H^ 

 and gain 2 atoms of oxygen + Oj 



Cg H^o Og 

 an atom of the hence-denominated formal. 

 As acetai can likewise be considered as being 



1 atom aether C4 Hjq ^ \ p u n 

 1 atom aldehyd C4 H^ O^j ^8 "is ^8» 

 so Can formal be considered as consisting of 



1 atom methylene aether Cg Hg O ^ p tt /-j 

 I atom methylene aldehyd C^ H4 i\J ^^ "10 '-'a- 

 To these considerations I shall have occasion to advert here- 

 after. 



Of the Pijroxylic Spiiit analysed by Liebig. — The composi- 

 tion of formal standing so closely in connexion with the result 

 obtained by Professor Liebig in his analysis of pyroxylic 

 spirit, rendered a further examination of this fluid highly in- 

 teresting, and the more so as Dumas, in the memoir on the 

 methylene combinations, expresses his inability to account for 

 the difference between their results, which, as was to be ex- 

 pected, resulted from the two chemists having examined two 

 completely distinct bodies. 



For the purpose of a new analysis. Professor Liebig was kind 

 enough to put into my hands a small quantity of his original 

 pyroxylic spirit which had remained in his cabinet of prepara- 

 tions. It was purified from some water and a brownish colouring 

 matter, by rectification over chloride of calcium, and possessed 

 the boiling point and other properties which that celebrated 

 chemist had assigned to it. On analysis, 0'470 of material gave 

 Water = 0-477 



Carbonic acid = 0*933, 

 from whence results the composition 

 Carbon = 51'-88 ") 

 Hydrogen = 11-27 > lOO'OO. 

 Oxygen = 33*85 J 

 Liebig*s former result was 1 Theory gives 



Carbon =54'-75| 

 Hydrogen =10-75 [lOO 

 Oxygen sSl-'SoJ 



4 atoms Carbon a 53-831 

 10 — Hydrogen a 10-97 [10000 

 2 — Oxgen a 35-20 J 



