Chemistry and Physies. 133 
compound, capable of true dissociation, the gaseous tension hence- 
forth depending alone on the tempera rs have 
prepared a table of the tensions of dissociation at different 
under pressure. 
capable of dissolving hydrogen, the quantity depending on its 
physical state. : 
In a second paper, Troost and Hautefeuille eerie results of 
gen.” This tube could be heated to any desired tempera- 
ture and kept there for any length of time. The authors found 
that no absorption took place when the potassium was melted, nor 
9 . 
while at 350° to 400°, the absorption goes on much more rapidly. 
Potassium-hydrogenium thus prepared, is a brittle substance, hav- 
at 300° and 760 mm. it dissolves 40 volumes of this gas. On oat 
pelling the excess of gas, a point determined by the agreement o 
gen to one of potassi the formula Ky requiring 124°6. So 
absorbs hydrogen actively between 300° and 421°, the tension at 
