REGELATION 



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pressure, the removal of the pressure will lead to the re- 

 freezing of the water produced. Hence we see that by 

 ' kneading " the powder of ice-crystals which we called 

 " snow " a minute quantity of water is first produced by 

 the squeezing, and then immediately is re-frozen when the 

 pressure is relaxed by the " kneading " hand. Con- 

 sequently at every squeeze a little air is driven out from 

 the powder, a little water takes its place, and when the 

 squeeze is relaxed this becomes solid, and cements 

 neighbouring crystals together, until, by repeated squeez- 

 ing artd relaxing, the whole lot of crystals may be joined 

 together into a solid mass by the re-freezing of the water 

 formed by the slight amount of melting. The ice so 

 formed encloses a great many tiny, almost invisible 

 bubbles of air. The process of melting by pressure and 

 re-freezing when the pressure is removed is called 

 " regelation." A glacier is nothing but a huge snowball 

 formed by regelation. The warmth of the sun causes the 

 surface layer of snow to melt a little ; the water so formed 

 percolates into the deeper layers where the heat of the 

 sun does not penetrate. It freezes again, and the solid 

 mass lying on a steep slope begins to press and move 

 downwards. It breaks and falls, and "regelates" with 

 neighbouring similar masses owing to their mutual pres- 

 sure. Always the slowly, or maybe quickly, sliding 

 masses adhere by regelation, and add to their solid bulk 

 by this kind of adhesion just as the much smaller rolling 

 snowball made by boys in the winter binds to it the snow 

 over which it is turned, and increases its solidity and bulk 

 at a rate which ha? become proverbial. 



Snow which falls when the air is at a temperature 

 below freezing has the form of six-rayed stars or crystals, 

 of great beauty and variety. In the highest Alpine 

 regions the fallen snow gradually loses its crystalline 



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