SCHLUNDT DIELECTRIC CONSTANTS OF PURE SOLVENTS. 365 



Mandelic Nitrile. — The preparation from which the sample 

 was obtained was of Schuchardt's manufacture. It showed de- 

 cided signs of decomposition, being of a dark brown color and 

 somewhat syrupy. It was dehydrated with fused calcium chlor- 

 ide, was filtered and distilled under diminished pressure, and the 

 sample thus obtained was redistilled. Its boiling point was 94° 

 C. under a pressure of 50 mm. A mobile, colorless liquid was 

 thus obtained whose specific conductivity was found to be 2.2 

 X 10" 10 reciprocal ohms. Its dielectric constant was found to be 

 17.82 at 23° C. An absorption of about the same order as 

 that of nitrobenzene was observed. Its absorption index was 

 also determined by the method outlined by Drude. 1 The value 

 obtained in this way was . 045, which agrees very well with that 

 of nitrobenzene which Drude places at .05. Drude has found 

 that this anomalous absorption is characteristic of compounds 

 containing hydroxyl. 



THE SUBSTITUTED AMMONIAS. 



The amines whose dielectric constants were measured are 

 enumerated in Table III. The samples used were Schuchardt's 

 preparations with the exception of the two toluidines and the 

 xylidine which were of Trommsdorff's manufacture. Each 

 sample, except methylamine, was dehydrated with fused potas- 

 sium hydroxide and then distilled ; and in many cases the distil- 

 late was again treated with fused potash and redistilled. The 

 sample of methylamine was doubtless impure for, upon evap- 

 oration it left a residue, and it did not yield a well defined 

 position for maximum resonance, while with all the other sam- 

 ples well defined maxima were observed. Hence the value 

 found for the D. C. of methylamine is doubtless too high. 



The third column in the following table gives the boiling 

 point of the samples taken for the measurements, and the 'fourth 

 column indicates the corresponding barometric pressure, while 

 the last column gives the temperature at which the D. C. was 

 measured. 



1 Zeit. phys. Chem. 23, pp. 292-297. (1S97;. 



