Messrs Fenton & Jones, On a method of comparing, etc. 109 
Based upon these changes a very simple method has been 
devised for Comparing the affinity-values of acids, and the results 
agree remarkably well with those obtained by the well-known 
methods. 
In order to explain the nature of the changes involved, the 
authors attribute the evolution of carbon dioxide to the instability 
of the negative ion, and they have now made further experiments 
in order to test this hypothesis, the results being in all cases 
favourable. It is further shewn that it is possible by this method 
to compare the ionizing capabilities of various solvents, and 
experiments have now been made with pyridine in order to throw 
light upon the disputed question of its behaviour in this respect. 
Von Laszczynski and von Gorski have found that inorganic 
salts have marked electric conductivity in pyridine solution, 
whereas Werner on the other hand found normal molecular 
weights from such solutions. 
Examined by the present method the following result was 
arrived at : 
0 1006 gram hydrazone dissolved in 7*5 c.c. of dry pyridine 
gave 6*12 c.c. of carbon dioxide (corr.). 
Under exactly similar conditions the following results were 
obtained with other solvents : 
Wt. of hydrazone Vol. of C0 2 
Water 0 - 0975 7'96 
Amyl alcohol 0’0989 3'56 
Toluene 0*1078 2-29 
Nitrobenzene 0T026 2*29 
It will be seen therefore that, on the hypothesis mentioned 
above, pyridine exerts a very considerable ionizing function. 
On isomeric esters of dioxymaleic acid. By H. J. H. Fenton, 
M.A., and J. H. Ryffel, B.A., Peterhouse. 
\Read 18 February 1901.] 
It was shewn by one of the authors on a previous occasion that 
the ethyl ester of dioxymaleic acid exhibits the remarkable pro- 
perty of becoming liquid when kept in a desiccator in presence of 
air, although it is relatively stable in presence of moisture or in 
absence of oxygen. This property has now been further investi- 
gated, and it is shewn that oxidation and loss of water take place 
with the formation of the liquid ester of dioxytartaric acid which 
VOL. XI. PT. II. 9 
