364 RELATIVE ATTRACTIONS OF 
tallowed to prevent the passage of air, but not 
exhausted. ‘This brass plate supporting the un- 
exhausted receiver, was placed in the immediate 
neighbourhood of the air pump, so as to ensure . 
the exposure of the two experiments to the very 
same temperatures. 
In these states, the dishes, the objects of expe- 
riment, were kept till the 8th November, when 
that under the exhausted receiver, was found, by 
weighing, neither to have gained nor lost the 
slightest weight ; but that under the unexhausted 
receiver, was found to be 0.7 grain heavier than 
at the commencement of the experiment. It being 
evident that the acid, in neither case, was suffi- 
ciently diluted to allow either a vacuum or dry 
air to rob it of any water at the temperatures it _ 
had been subjected to, the dilution was carried 
further. The acid in the dish under the ex- 
hausted receiver, had water added to it until the 
total quantity of water diluting the 200 grains of 
concentrated acid was 76.1 grains ; and that in the 
dish under the unexhausted receiver, had water 
added till the total quantity diluting the 200 
grains of concentrated acid was 75.5 grains : both 
dishes being placed under their respective re- 
ceivers, were kept there, as before, till the 15th 
