[baknes] artificial PRODUCTION OF FRAZIL ICE 31 



Au effort was made to obtain readings for definite quantities of 

 frazil ice. It was impossible to form an estimate of the quantity of 

 ice formed by the chilled air, but clean dry snow was weighed outside 

 the building, and added to a known weight of water. In our two series 

 of tests, one set with the Beckmann and the other set with the platinum 

 thermometers, we used different weights of water. The differences 

 observed were practically the same in the two cases. The rate at which 

 the chilled air was passed through was also the same. The differences 

 observed were in practical agreement with the measurements made 

 during the severe weather in the open water in the Lachine Rapids. 



It was found that witih the Beckmann tlhermometer the tempera- 

 ture of the water just at the time when the first ice crystals were formed 

 was of the order of a hundredth of a degree. On adding successively 

 5, 10 and 20 parts by weight of ice the difference Avas reduced. This 

 showed us that with very rapid cooling the temperature of the water 

 never fell much below the freezing point. After repenting our ex- 

 periments several times, we replaced the mercury thermometer with the 

 differential platinum thermometers, and used a larger supply of water, 

 about 400 cc. The readings we obtained are as follows: — 



Ice just fonning — -0140° C. 



loe 20% . —0060° C. 



These measurements were checked several times, and all the con- 

 ditions of the experiment were such as to warrant entire confidence in 

 the results. 



During the time in which the water was in this undercooled state, 

 the fine needle crystals exhibited very completely the phenomenon of 

 agglomeration. They appeared to be in a very adherent state, as shown 

 by the formation of spongy masses and the accumulation about the 

 thermometer bulb and stirrer. They adhered, of course, to the tubes 

 leading in the chilled air, but not to the wall of the vessel, which was 

 surrounded l)y the snow and water, and could not have been therefore 

 far from 0°. 



On withdrawing the vessel and examining the ice formed, it was 

 f ( und to resemble very closely the natural frazil crystals from the river. 

 It was in a flocculent state, floating low in the water, easily kept under 

 by the light masses at the surface. 



It is possible to draw valuable conclusions from these experiments in 

 regard to natural temperature conditions in the water. Since the maxi- 

 mum temperature depression in the severest weather is not likely to be 

 more than a hundredth of a degree Fahrenheit when the frazil ice is in 



