supplied by the large bottles A and B. The pressure head was 
registered in the manometer M. The time required for the ferric — 
chloride meniscus to fall from the mark s to the mark s’ was 
taken by means of.a stop-watch. Care was taken to ensure that 
the ferric chloride solution had acquired the temperature of the — 
bath before a reading was obtained, and to secure this the bulb 
was filled in the following way. The solution was drawn into the 
bulb till the latter was about half full, and the U-tube was shaken | 
by sliding the inlet and outlet tubes backwards and forwards — 
through the holes in the side of the calorimeter. Meanwhile the 
liquid in the bath was kept well stirred. More liquid was drawn 
into the bulb and the shaking repeated. Finally the bulb was 
filled, and since the solution last admitted filled the capillary and 
part of the outlet tube, it soon acquired the temperature of the 
80 Mr Oxley, Magnetic Susceptibility with Temperature. 
Fig. 4. 
bath. An interval of about twenty minutes was usually allowed 
for the solution to acquire the temperature of the bath, but for the 
higher temperatures a much smaller interval had to suffice, on 
account of radiation, while at temperatures near that of the room 
an hour was frequently given*. . 
The method of taking an observation was as follows. The end 
of the outlet tube was kept below the level of the solution in & 
and the three-way cock 7’ turned so as to shut off 6 and connect 
B with M. The pressure head was now adjusted to a certain 
value, approximately the same for all the observations. 7’ was 
turned so as to connect B, M and b, R was lowered and the time 
taken as the meniscus passed the mark s. 
The following observations were made : 
* The small bubbles of air which were always formed in the outlet tube were 
removed before an observation was made. 
