67 



The formation of the ice behind a layer of earth usually occurs on more 

 level ground, because, I believe the ground is rarely wet enough close to the 

 surface to afford a proper supply of water. 



As a detail it may be interesting to consider how the icicles of the 

 columnar form, become contorted. The most common form of this is for their 

 extremities to be curved downwards as if they had bent with their own weight, 

 and this is strictly true, though the bending occurs during and not after their 

 formation. When a minute portion of the column is formed, it retains its 

 position against the bank solely by capillary adhesion, and consequently, hangs 

 by its weight a little downwards. Its growth is however directly outwards, and 

 so long as the growing icicle is retained by capillary adhesion and obtains no 

 support by falling against other columns the result is to produce a downward 

 curve in the ice column ; when the ice columns by falling against each other in 

 this way obtain even a slight support they grow directly outwards and are con- 

 sequently straight. If they do not obtain sufficient support in this way, as soon 

 as their weight exceeds the sustainiog power of the capillary adhesion they fall 

 off and the process begins de novo (applause). 



Mr. Lloyd asked Dr. Chapman some questions with reference to the 

 formation of river ice, which were answered, but the remarks elicited bore 

 upon a different series of facts in ice formation. 



