HAILSTONES^ RAINDROPS^ AND SNOWl'LAKES. 



167 



of the hailstone. It is quite white and opaque ; it is co- 

 nical in form^ and has a rounded base and striated surface. 



In this way I have formed stones from half to three 

 quarters of an inch in diameter. When, however, the 

 stones are growing large, it is necessary to move this 

 splinter so as to expose in succession all parts of the face 

 of the stone to tlic more direct action of the spray. 



When using this apparatus in a warm room, I have found 

 it best to fix a pad of blotting-paper over the jet at a height 

 of ten or twelve inches. The surface of this pad is cooled 

 by the spray and prevents radiation from the ceiling, which 

 otherwise tends to melt the top of the stone. For a simi- 

 lar reasoii I have found it well to surround the blast with 

 a wide cylinder or inverted cone of paper, which keeps off 

 radiation witliout interfering with the action of the jet. 



By sticking several splinters of wood pointing downwards 

 into the pad, a number of stones may be made at once. 



In the accompanying sketch are shown a medium-sized 



stone, as well as one of the largest stones, attached to tlie 

 splinters of wood. The surface of the cone where conti- 



