1878.] 



On Conductive Properties of Ice. 



183 



portion of the time, so that the magnitude of the " wabble " wonld be 

 reduced by the friction of the 306-day tide ; for we are by no means 

 compelled to believe that that inequality of motion must always have 

 remained as small as it is at present. 



It appears to me, from these considerations, that the continents of 

 Europe and Asia might have been elevated in very much less than 

 20,000 years, and yet leave no record of the fact in the present motion 

 of the earth. Therefore, if my solution of the problem is correct, 

 it is certain that Professor Haughton's method can give us no clue to 

 the times which have elapsed in the geological history of the earth. 



II. " Some Experiments on Conductive Properties of Ice, made 

 in Discovery Bay, 1875-6." By Staff Surgeon K. W. 

 Coppinger, M.D. Communicated by Professor TYNDALL, 

 F.R.S. Received February 21, 1878. 



In attempting a series of experiments for determining the rate of 

 conduction of heat through sea and fresh-water ice, I have endeavoured 

 as closely as possible to follow the suggestions made by Professor 

 Tyndall in page 34 of the " Scientific Instructions for the Arctic 

 Expedition." With this view, I have constructed the simple appa- 



ratus shown in the diagram. It consists of a wooden baseboard (F F), 

 29 inches in length by 9 in breadth, on which are fixed two upright 



