SNOW-MUSHROOMS AND CAHOTS 227 



On the S parse ness of the Fatting Snowftakes. 



During a heavy snowfall the air appears thick 

 with snowflakes. When the fall is so heavy that 

 it accumulates to the depth of i foot in an hour, 

 as sometimes occurs at Glacier House, the air must 

 look so full of snow that the flakes would seem 

 to occupy a considerable proportion of the whole 

 space. I found, however, by timing the descent 

 of many snowflakes and taking an average, that 

 their rate of settlement was 2 miles per hour. 

 Therefore when snow collects at the rate of i foot 

 in an hour a column of the snowy air 2 miles, 

 or 10,560 feet, high and of i square foot section 

 only contains enough snow to form a deposit of 

 I cubic foot in bulk. Thus the falling flakes 

 occupy less than one part in ten thousand of the 

 space in which they seem to be so crowded. 



On " Cahots,'" the Surface Waves Produced by 

 Sledges. 



In December, 1901, I noticed that the snow 

 in some of the streets in Montreal and on the 

 driving track across the frozen St. Lawrence had 

 a remarkably undulating surface, obviously due to 

 the sledge traflic. The average length of these 

 undulations from crest to crest was 13 feet. The 

 length of the sledge-runners varies, but 5 to 6 feet 



