152 ROYAL SOCIETY OF CANADA. 
and 40 cms. high. The top could be securely bolted down and was 
rendered water-tight by means of a leather washer. A brass tube, 
about 14 cms. in diameter and 30 cms. long, was soldered in an 
upright position into a hole in the centre of this cover, forming 
a long, narrow neck through which the suspension wire could hang 
freely from the balance arm down into the interior of the vessel. 
This long neck also rendered it possible to completely immerse the 
vessel in the mixture of snow and water. In the lower part of 
the vessel an outlet was constructed of a bit of bent brass tubing 
soldered in position. To this orifice a very long piece of brass 
tubing was attached by means of a rubber neck, this tubing project- 
ing above the snow and water, and preventing this mixture from 
entering at the lower opening. By pulling out this tubing the water 
could be allowed to enter the vessel and cover the suspended specimen 
of ice. In case the inflow of water should carry in small particles 
of snow, which would tend to vitiate the observations, a piece of 
fine wire gauze was fastened to the inside of the vessel, just above 
the inlet, which therefore cleared the water of all particles of snow 
before it reached the specimen of ice. 
The outside vessel, which contained the snow and water mix- 
ture, was of copper and about 60 ems. in diameter by 70 cms. high. 
Thus when the inner vessel containing the specimen was imbedded in 
this mixture, it was surrounded by a wall of snow and water ranging 
in thickness from 15 to 20 ems., more than sufficient to prevent any 
possibility of transmission of heat from the outside. 
The balance used was one constructed by Oertling, and very 
sensitive. A hole was bored in the bottom of the case and also 
through the supporting table to allow the free passage of the suspen- 
sion to the rest of the apparatus, which was placed under the table 
during the weighings. 
The following was the method of carrying out an experiment: 
A piece of ice was cut from the solid block a little larger than 
required. This was then reduced by washing in cold water, which 
removed all traces of chipping and crevices due to the cutting. It 
was then put aside and allowed to come to zero temperature, shown 
by its tendency to melt. Meanwhile, the mixture of snow and water 
was prepared, the inner vessel imbedded in it with the top off and 
the apparatus taken into the open air, the temperature during the 
days of the experiments never being far from 0° C. The specimen 
was then taken outside, carefully dried with filter paper and a linen 
rag, placed in the weighted grip, and placed inside the inner vessel, 
the specimen never being touched by the bare hand during these 
