(2171) 
Measurements are obtained with the above as follows. First the 
cock A is shut and the liquid gas allowed to stream into the 
boiling glass. When a sufficient quantity has collected there, and 
we may consider that the whole of the condenser has assumed 
the temperature of the gas, the inside of the hollow cylinder is 
evacuated through the glass tube g and the capacity of the conden- 
ser determined. The cock A is then opened so that the liquid gas 
streams into the inside of the cylinder in consequence of the pres- 
sure. When this operation is finished the cock / is again shut and 
the capacity of the condenser redetermined, this time with the 
liquefied gas as a medium’). 
In order to be certain that the cylinder was full of liquid gas the 
gauge MN was found to be necessary, in which the level of the meniscus 
indicates outside the level of the liquid in the cylinder or the glass 
tube g adjacent to it. The glass tube / which connects g to N 
allows an equalization of pressure *). 
It was unfortunately impossible for the electrometer and above 
mentioned auxiliary apparatus to stand in the room where the 
refrigerating machinery is installed, partly from want of space and 
partly because of the inevitable vibration caused by the working of 
and attendance on the pumps. Hence I had simply the choice be- 
tween, placing the boiling flask containing the condenser in the 
neighbouring room where the electrometer already stood; or keeping 
the boiling flask in the eryogenic laboratory and connecting the 
condenser to the electrometer by adequately long leads. In the former 
case the liquefied gas would have to be conveyed to the boiling flask 
through about 5 m. of tubing into which it would be very difficult 
to prevent the entrance of heat, and a successful termination of the 
research would be doubtful. This consideration caused me to primarily 
favour the latter arrangement, although the sensibility of the method 
is undoubtedly diminished owing to the non-neglectable capacity 
represented by the long leads. Finally I considered that the advantages 
of the latter arrangement outweighed its disadvantages. 
It appeared to be necessary to eliminate the influence of the long 
indicated ; 7, p, 9, Uy, U, Wy, Wy see Comm. N°. 51 § 2; ¢, ¢, copper mountings to 
fasten steel pins v,, v‚. The lateral opening of the glass tube g can be clearly seen 
in front of the side tube u, of the brass 7 tube. 
1) In the first of the three sections given the beaker and condenser are empty, in 
the second the beaker is full and in the third both are full of liquid gas. 
2) The gauge has been turned in the second section in order to show Z. As remarked 
above the gauge has not been drawn in Plate I. Comm. N°, 51 § 2, it is observed 
through K, (Pl. I,-loc. cit.). 
