Singular Inflation of a Bladder. 89 



trance of carbonic acid gas into the bladder depends, therefore, 

 upon no peculiar property of coal gas. The bladder, partially 

 filled with coal gas, did not expand at all in the same bell-jar 

 containing common air or water merely. 



M. Dutrochet will probably view, in these experiments, the 

 discovery of endosmose acting upon aeriform matter, as he 

 observed it to act upon bodies in the liquid state. Unawar j of 

 the speculations of that philosopher at the time the experi- 

 ments were made, I fabricated the following theory to account 

 for them, to which I am still disposed to adhere, although it 

 does not involve the new power. 



The jar of carbonic acid gas standing over water, the bladder 

 was moist, and we know it to be porous. Between the air in 

 the bladder and the carbonic acid gas without, there existed 

 capillary canals through the substance of the bladder, filled 

 with water. The surface of water at the outer extremity of 

 these canals being exposed to carbonic acid, a gas soluble in 

 water would necessarily absorb it. But the gas in solution, 

 when, permeating through a canal, it arrived at the surface of 

 the inner extremity, would rise, as necessarily, into the air in 

 the bladder, and expand it. Nothing but the presence of car- 

 bonic acid gas within could prevent the disengagement of that 

 gas. The force by which water is held in minute capillary 

 tubes might retain that liquid in the pores of the bladder, and 

 enable it to act in the transit of the gas, even after the pressure 

 within the bladder had become considerable. 



Account of an Apparatus for ascertaining the value of different 



Alkalis. 



To the Editor of the Quarterly Journal of Science, &c. 



Sir, 



I herewith send you some account of an apparatus which 

 I have employed for many years in ascertaining the value of 

 the different alkalis of commerce ; it is more simple and less 

 liable to variation in its results than any with which I am 

 acquainted as proposed for the use of persons not familiar 

 with the niceties of chemical analysis. You will observe that I 



