418 
MESSRS. T. E. THORPE AND J. W. RODGER OH THE RELATIONS 
able, the latter may be filled, and must be emptied before the observations can be 
commenced. 
When the volume of liquid in the glischrometer had been adjusted, the rubber 
tube Q was detached from the glischrorneter, which was then lowered, the siphon 
moved aside, the tubes E and E' (fig. 2) fitted to the right and left limbs, and the 
ends of each stopped with a glass rod. The frame and glischrorneter were now removed 
from the filling stand, and any small air bubbles which occasionally lodged in the inter¬ 
space between the capillary tube and the cross piece of the glischrorneter were 
removed. The thermometer was now fitted to the frame, which was next lowered into 
the slots in the sides of the bath. The water-bath was used for low temperature 
observations, and in the case of this bath, the stirrers were next introduced. The lid 
of the inner compartment, which was pierced with holes for the rubber tubes and the 
thei’mometer, was then fitted on, and the bath placed in position directly under the 
pulley over which passes the cord leading to the motor. 
In the case of the glycerin bath, the stirrers remain permanently in the liquid, the 
glischrorneter being introduced by unscrewing the cross pieces connecting the stirring 
rods and taking off the lid covering the inner compartment. This lid is made in one 
piece, and can only be removed in this way, or along with the stirrers as is done in 
the case of the water-bath. After adjusting the position of the bath, the rubber tubes 
E, E' (fig. 2) were at once fitted to the glass tubes O, O' respectively, and the cocks 
Z, Z' turned so as to put the limbs of the glischrorneter in connection with the air 
reservoir L, and thus under equal pressures. The water reservoir was then raised to 
the required height, care being taken to wet the walls of the manometer for some 
distance above the points where readings were to be made. In this way, before the 
first observation was started, and in the interval between subsequent observations the 
experimental liquid was kept under the increased pressure of the air in the reservoir. 
Two advantages arise from this arrangement. In the first place, the air in contact 
with the liquid is dry, which would not be the case if the pressure in each limb were 
kept equal by putting the three-way cocks to air, and secondly, evaporation of the 
liquid in the glischrorneter under the increased pressure is retarded. At high tempe¬ 
ratures tlie loss of liquid by evaporation during the interval between two observations, 
when the temperature is being raised, and afterwards when it is becoming steady, 
would in some cases be so great as to impair the volume necessary for the next 
observation if the liquid were kept at atmospheric pressure for such a length of time. 
Having established the pj'essure and having adjusted the length of the cord leading 
from the stirrers to the motor, the latter was put on to the water main and the 
stirrers set in motion. 
If tlie experimental liquid did not solidify above ice was now introduced into 
the outer conqiartment of the bath, and as it melted the supply was replenished, the 
water formed being removed at intervals by tire tap. The motor was easily con- 
