$ Sir Gr. Greenhill on 



But in Be van's experiment the tongue of ice was left 

 supported on the water, and deflected by a weight at the 

 free end ; and then, if the ice was deflected d inches by a 

 weight of P lb at a distance a from the root, in a tongue 

 b inches broad and e thick, 



'md = ±pke>bd=±Fa\ * = -jgJ • • (4) 



in accordance with the usual formula. 



In an experiment, P = 25, a = 98, 5 = 10, £=4, and by 

 measurement d = 0*206 inch; so that with a specific volume 



of ice or water - = 27*73 inch 3 /lb, 

 P 



, 4x25x27*73x98 3 . , 



k= 4? x 10x0-256- inches > ■ • ■ (« 



and this works out to about 20 million. 

 Then for the skin stress, ph, 



and this works out to 



| = 0*00012, h = 3000 inches, 250 feet, . . (7) 



still rather long for an icicle. 



9. Pack ice is produced by thrust in the surface. Esti- 

 mated at a pressure P=/?c, the D.E. (1) § 4 is modified into 



*S=-^S-^S+^ • • • « 



d 2 7i 

 and for ice at rest, -^-=0, Sp= —pVi 



Here the sign of P and c would be changed for a super- 

 ficial tension, as of the capillary film in § 1, or a cloth on 

 the surface. 



