83 
of Edinburgh, Session 1866-67. 
alcohol, when treated with one-third of the quantity of perman- 
ganate of potash necessary for complete oxidation, gives oxalic 
acid. If the oxidising agent had been in excess, we could not have 
considered the action specific ; but as Berthelot has shown that 
acetylene can be condensed into benzol, and that acetylene, when 
oxidised, gives oxalic acid, we must consider the production of 
oxalic acid as depending on the more intimate union of the two 
carbon atoms. 
By the regulated oxidation of phenyl alcohol several substances 
must be produced. If we compare benzol and naphthalin, both 
members of a homologous series of hydrocarbons where the common 
difference is C 4 H. 2 , we would expect them to undergo a similar 
decomposition on oxidation. And as naphthalin, when oxidised, 
gives oxalic and phthalic acids, thus 
C 8 H 6 . C. 2 H 2 + 0 8 = C 8 H 6 0 4 + <xh 2 o 4 , 
so we would expect benzol to give oxalic and fumaric or an isomer, 
thus 
C 4 H 4 . C 2 H 2 + 0 8 = C 4 H 4 0 4 + c 2 h 2 o 4 . 
But if the resisting nucleus in benzol be C 4 H 2 , we would expect 
the formation of an acid, C 4 H 2 0 4 mellitic. So far as my experiments 
have gone, they prove the formation of two other acids along with 
oxalic, when two molecules of permanganate of potash to one 
of phenyl alcohol were used. When the alkaline liquid, after 
filtration from the manganic oxide, is strongly acidulated with 
hydrochloric acid, shaken up with ether, and the ethereal extract 
evaporated on the water-bath, a yellow resinous acid, giving a 
purple colour, with ferric chloride, is left. If this substance is 
heated, it chars, giving a beautiful sublimate in the form of long 
needles. The crystalline acid has a styptic taste, and gives a 
strong reddish violet reaction with ferric chloride, but no reaction 
with ferrous sulphate or lime water. The acid, therefore, differs 
from pyrogallic. Whether this crystalline acid is a decomposition 
product of the resinous acid, or the same substance separated from an 
impurity, further experiments must decide. When the acid liquid 
left, after separating the ether, is evaporated to dryness, treated 
with alcohol to dissolve the oxalic acid, freed from alcohol by eva- 
poration, and the lime salt precipitated in presence of acetic acid, 
