[BARNES & COOKE] ~ THE DENSITY OF ICE 151 
of fact, as Nichols has also pointed out, it is the only one that has 
yielded consistent results in each of its applications to the measure- 
ment of ice density, and it is evidently to this method that one must 
look for a final determination of the absolute value. 
It was owing to a consideration of these facts, that the method 
of weighing was adopted in the following series of ice determinations 
carried out in the Macdonald Physics Building, during the winter of 
1900-01, by the authors. 
The objections to which former methods of weighing were open, 
that the ice during the experiments was not at the temperature for 
which the density was required, was eliminated by the arrangement 
employed in these determinations, the ice first being weighed in air 
at zero, and then in water at the same temperature; the water being 
unable to act upon the ice without the access of heat, which was 
prevented by the experimental arrangements. 
The ice is placed in the weighted grip which is suspended from 
the arm of a sensitive balance by a fine wire. This wire passes 
through a long, narrow tubular opening in the cover of a copper vessel, 
which is surrounded by a mixture of pure snow and water and the 
entire contents thus brought to zero. After the ice has been weighed, 
pure water at zero temperature is admitted into the vessel, and after 
this has completely covered the suspended ice, the weight is again taken, 
and from the loss due to immersion, the density of the ice is calcu- 
lated, due corrections being made for the weight of the suspension 
and grip and for the density of the water. 
, The general arrangement of the appa- 
ES cs ratus is shown in the accompanying diagram. 
The grip was made of flexible brass wire, 
about a millimetre and a half in diameter, 
the three prongs and the end of suspending 
wire being very carefully soldered together. 
To the lower end of each prong a short piece 
of fine lead tubing was then soldered to 
counteract the tendency of the ice to rise 
to the surface when immersed in the water. 
The greatest care was taken in the soldering 
to prevent cracks or inequalities of the sur- 
face upon which bubbles of air might have 
lodged during immersion. The upper end of 
the wire ended in a hook, by which it could 
be attached to the arm of the balance. 
The copper vessel inside which the grip 
was suspended was about 15 cms. in diameter 

