298 So7ne llemarks on MM. Francis and Croft's 



C4 Hg Oo = C4 H5 O. In the experiment just described H 

 is given off, and it is concluded that aldehyd is analogous to 

 hydruret of benzule, while a few months ago the opinion of its 

 beinw a hydrate of oxide of acetyl was promulgated ; and both 

 opinions are founded on experiment I but this by the way. 



(4.) To return to the theory of alcohol. After stating, as 

 above, the decompositions produced by hydrated alkalies, the 

 abstract (for with that alone I am at present dealing) proceeds 

 — " In the usual preparation of acetic acid, two atoms of hy- 

 drogen are replaced by two atoms of oxygen ; by the action 

 of alkalies chloracetic acid C4 H CI3 O4 [the hydrated acid] 

 is decomposed into carbonic acid and chloroform Co O4 + Cg 

 H CI3 ; acetic acid is decomposed into Cg O4 + Cj H4, or 

 C^ Q^ + Cg Hg H. Alcohol may therefore [1] be considered 

 as' composed of two bodies representing carbonic acid, one 

 the methylic aldehyd, the other marsh gas, C4 Hg Og = 

 Co H3 [intended, I suppose, to be H4] + C^ Hg O^ = [or 

 analogous to] Co O4 + C^ O4." Why we are to consider 

 alcohol as composed of marsh gas and methylic aldehyd, to 

 me is by no means obvious from these premises. If, how- 

 ever, we are to imagine it as containing a compound of the 

 methyl series, we might, as it seems to me, with as much reason 

 suppose alcohol an oxide of methyl (C2 H3 + O) with which 

 it is evidently isomeric. But I forget myself; this supposition 

 is contrary to the theory of types. 



The abstract continues : " In the usual method of forming 

 acetic acid Co H, Oj loses H, and takes up O., there then 

 remains C^ O^ O^' + Cg H4 = 'C4 H4 O4, or acetic acid. By 

 the action of alkalies H4 is given off; the water of the hydrated 

 alkali is decomposed. Ho is developed, and O^ assimilated." 

 If these changes really occurred, it is evident the result would 

 be an oxalate, not an acetate. 



1 eq. hydrated acetic acid = C4 + H4 + 04~| 



2 eq. water from the alkali = Hg + O2 1 _ 



C4 + Hg + OgJ 



I^Ji- Og 2 eq. oxalic acid. 



H4 Evolved. 



Ho Evolved. 



C4 + Hg + Og 



Hence it appears that the alkalies act, by their affinity for 

 carbonic acid, in a manner analogous to that in which sul- 

 phuric acid operates by its affinity for water. 



(5.) Lastly, we may consider alcohol a bihydruret of aldehyd, 

 and still appeal to experiment for confirmation of our view ; 



