424 The Density and Coefficient of Cubical Expansion of Ice. 



Weighted mean ... 0-9160 



We thus obtain 0*9160 gramme per cubic centimetre as the density 

 of ice at C. 



Four values for the coefficient of cubical expansion can be obtained 

 from these results. They are : 



Experiment. Coefficient of cubical expansion. 



1 0-000155 



2 0-000152 



3 0-000153 



4.. 0-000148 



Mean 0-000152 



The results of this investigation are that Nichols' value for the 

 density of artificial ice is confirmed, but that since the same specimen 

 of water can freeze into specimens of ice having different density, the 

 use of the Bunsen ice calorimeter in absolute determinations must be 

 limited to an accuracy of probably one in a thousand. 



The expenses of this research have been in part defrayed by a 

 Government grant from the Royal Society, and in part by the 

 Cavendish Laboratory. 



I wish to thank Professor J. J. Thomson, F.R.S., for his kind en- 

 couragement, and my thanks are also due to Mr. E. H. Griffiths, F.R.S., 

 through whom I was led to undertake the investigation. 



