302 Wisconsin Academy of Sciences, Arts, and Letters. 
proportions. Although, this view has of recent years been 
relegated to the background by many, it certainly has a for¬ 
midable array of facts to support it; and such facts have really 
been accumulating more and more, though the investigations 
yielding them have been guided to a considerable extent by the 
analogy between gases and solutions. If when a substance is 
dissolved in water chemical combination between that substance 
and water takes place, the liberation of hydrogen from the solu¬ 
tion ought to result with a different degree of readiness than 
from pure water. With this as the guiding idea, Mr. O. W. 
Brown and Dr. II. V. Black at my suggestion m|ade some pre¬ 
liminary experiments in this laboratory last summer, compar¬ 
ing the rate with which hydrogen is evolved from various 
aqueous solutions by the action of magnesium upon them. In 
the course of these experiments (among which many of the ob¬ 
servations of the above named Drench investigators were con¬ 
firmed, though at the tim'e their researches had not been looked 
up) it was found that hydrogen was liberated with different 
rapidity in the case of each solution tested, and that this rate 
was different from that observed when pure water was used. 
To my regret Messrs. Brown and Black were unable to con¬ 
tinue these investigations, much as they were inclined to* do 
so. It seemed to me well worth while to follow out somewhat 
farther the w T ork thus begun, and the results obtained in in¬ 
vestigating the subject will now be presented. 
The metallic magnesium used was of Schuchardt’s manu¬ 
facture. It was carefully tested and was found to be free from 
carbon, and from alkali and alkaline earth metals. 0.8593 : 
grams of the mjetal yielded 0.0036 grams of the mixed sesqui- 
oxides of iron and aluminum. Other metals were not present 
in the magnesium. The latter was cut into bars of square 
cross section measuring 5 mm. on an edge:, and having a length 
of 51.5 mm,., thus presenting a surface of 1,200 sq. mm. A 
large number of such bars was prepared. In each liquid to be 
tested, such a bar was immersed, its surface being first care¬ 
fully cleaned with fine emery cloth. The action of the metal 
upon the liquid was noted and the volume of hydrogen evolved 
at different times was observed. The experiments were con- 
