Section III., 1904 [ 3 ] Trans. R. S. C 



* 

 I. — Note on an Apparently Accidetital Formation of Frazil Ice in a 



Cryopliorus. 



By Professor John Cox. 



McGill University. • i 



(Read May 19, 1903.) 



In the ordinary experiment wdth the cryophonis the lower (empty) 

 bulb is placed in a freezing mixture, the water vapour is condensed, 

 and the rapid evaporation in the vacuum so produced soon causes a 

 film of ice to form on the surface of the water in the upper bulb. In 

 the course of a lecture to the students of the First Year Arts last Jan- 

 uary, I performed this experiment for perhaps the hundredth time 

 with a result which I had never observed before, and which seems worth 

 placing on record. 



The experiment had for once failed at the preceding lecture. The 

 freezing mixture of snow and salt was accordingly made with special 

 care, and well bedded round the bulb. But there was again no result, 

 and I began to think a minute crack had occurred, letting down the 

 vacuum of the cryopliorus. As the lecture went on T occasionally 

 looked at the cryophorus, but no ice was formed for about half an 

 hour. A minute or two afterwards a confused mass of long needles 

 formed and grew rapidly, projecting in all directions, many of them 

 vertically downwards. The formation was so different from the usual 

 cake adhering to the sides, that I removed the instrument and carried 

 ii round to the class, holding it still vertical, in ord.er that they might 

 examine it more closely. ' To my great surprise the mass of needles, 

 loosened by the movement from the sides, sank slowly to the bottom 

 and remained there with, perhaps, one-third of an inch of clear water 

 above it. I called the attention of the class to this curious fact, and 

 suggested that it might have some relation to the alleged formation 

 of frazil and anchor ice in the St. Lawrence, though this was said 

 to occur where the water was disturbed, whereas the cryophorus was 

 resting on a pier with independent foundations and free from all 

 vibration. 



I have repeated the experiment a number of times with varying 

 conditions but have failed to obtain the result again. In the actual 

 case it seems likely from the length of time before the ice formed and 

 the steadiness of the supporting pier that the water was considerably 

 supercooled. I have tried steadiness with slow cooling by freezij 



