I.UEDEKING — PHYSICO-CHEM. STUDIES IN FATTY ACID SERIES. 633 



c gives the observed specific heat, while that headed c' gives the 

 specific heat as calculated as a mean of the constituents ; the 

 column clc' shows the amount of deviation from this calculated 

 mean of the experimentally determined values. 



To facilitate comparison I have appended in Fig. III. a curve 

 for each acid in which the values c'c^ are ordinates, whilst the 

 values n' are abscissas. 



Formic Acid. 

 Specific heat between 50° and 16°. 



The formic acid used in these determinations was the same as 

 that used above in the specific gravity determinations. 



The figures and the curve show that the values clc' increase 

 very rapidly at first to a maximum corresponding to the formula 

 'CH2O2 + iHgO. Then these values decrease very precipitately 

 and reach a minimum at the third hydrate, when they again in- 

 crease to reach a second smaller maximum at the fourth hydrate. 

 At the sixth hydrate a second smaller minimum is reached, and 

 from thence on the curve approaches the unit value of clc' very 

 gradually. 



