Qualitative Determinations. 
399 
seldom that any resistence had to be introduced by means of 
the rheostat. A hundredth normal solution of sulphuric acid 
gave a deflection of about twenty divisions when 500 ohms resist¬ 
ance was introduced. By means of a direct current thus em¬ 
ployed polarization of course could not be avoided. The circuit 
was only closed for a few seconds. The sole object of these ex¬ 
periments being to ascertain whether the solution conducted, 
and to determine only very roughly the relative magnitude, 
the slight amount of polarization could be entirely neglected. 
The solvents were all of the C. P. variety of standard makes: 
Kahlbaum, Merck, Schuchardt, or Trommsdorff. Professor 
Kremers of the pharmacy department of this university kindly 
furnished several compounds from his collection and Professor 
Hillyer kindly placed at my disposal a number of solvents in his 
possession. For thus furthering the experimental work, I desire 
to extend to these gentlemen my thanks. The methods em¬ 
ployed in rectifying and dehydrating these solvents will be 
found under the head of the particular solvent in the record of 
the quantitative determinations. 
The salts employed were absolutely anhydrous and the method 
employed in their preparation and dehydration will now be 
given. 
Ferric chloride was prepared by passing anhydrous chlorine 
over heated iron wire contained in a hard glass tube. The 
chlorine was prepared in the usual manner from manganese di¬ 
oxide and hydrochloric acid. The gas was conducted through 
a wash bottle containing water to free it from hydrochloric acid, 
then through sulphuric acid, then through a cylinder containing 
fused calcium chloride, and finally through another wash bottle 
containing sulphuric acid. From this it was conducted into the 
long hard glass tube containing the fine iron wire. This tube 
was gently warmed, and by increased heat the chloride was sub¬ 
limed along the tube. This resublimation was repeated several 
times, and then the tube was sealed off and the product pre¬ 
served in these sealed tubes. Before using, the tube was opened 
and allowed to remain under a bell iar containing concentrated 
sulphuric acid for several days, when not the least trace of free 
chlorine could be detected in the salt. 
