232 



Prof. Oersted on the Law of the 



is introduced into the cylinder AAAA, where the dish FF is 

 plunged in the mercury, which is below the line HH : The 

 cylinder is filled with water, and the body BBBB of the 

 pump is put in and filled with water. The piston DD is 

 finally put in, and is made to act upon the inclosed water. 

 This water communicates its pressure to the mercury, which, 

 in its turn, transmits it to the two aeriform materials contain- 

 ed in the tube. 



The following are the results of the experiments with two 

 tubes, one of which contains atmospherical air, and the other 

 sulphurous acid gas, the temperature being 21 \° centigrade. 



