[barn es] 



NOTES ON FRAZIL AND ANCHOR ICE 



21 



point mixture with the rate of formation or solution of ice, but, owing to 

 the stress of other work, the author has been able no more than to design 

 and have partially constructed the apparatus necessary. In the near 

 future it is hoped the work may be continued. In the meantime, a con- 

 sideration of the observations made under different conditions on the 

 river show that where there is a large quantity of water at the freezing- 

 point being rapidly cooled, the temperature of the water does not remain 

 exactly at 0° C, but sinks a few thousandths of a degree below. Cor- 

 respondingly, where the ice is melting, the temperature rises above the 

 freezing-point about the same amount. Under surface ice such large 

 variations are not so common, on account of the larger quantity of ice. 



It appears that there may be drawn certain conclusions relatively 

 to the complete -change of a quantity of water into ice and vice versa. 

 If it is imagined a quantity of water subjected to a uniform and 

 definite loss of heat at the freezing-point, and continuously stirred, so 

 as to produce intimate mixing between the ice and water, then it is 

 probable that the temperature will fall slightly below the freezing-point, 

 of the order of a few thousandths of a degree, will gradually approach 

 the freezing-point as the quantity of ice grows, until finally, as the ice 

 predominates over the water, the temperature will drop again. Con- 

 versely, if it is imagined a quantity of ice melting, and if possible sub- 

 jected to constant stirring, then the temperature will rise slightly above 

 the freezing-point, depending on the amount of heat being absorbed. 

 The temperature will then drop, more and more approaching-the freez- 

 ing-point as the quantity of water increases, until the quantity of water 

 begins to predominate, and then will rise again. 



Schematically the complete process may be represented as in the 

 figure by following the arrows. 



DEaSEE C. 



+ 0-or 



-001 



IOÛ % ICE 



