216 



The apparatus and plan of the experiment was practically tlie same 

 as in my former work. The pump was a Ducretet compression pump fitted 

 with a gauge recording pressure up to 1,000 kilogi'ams per square centi- 

 meter. The cell is made in the H form with very short connecting tube 

 (Fig. I), so that it will go inside the piezometer (Fig. II), whose inside 



Fig III. 



