Manchester Metnoirs, Vol. xliii. (1899), No. 5. 



5 



using a common soldering-iron, and was in the act of 

 testing the copper point of the hot iron to see if it was hot 

 enough to melt the solder, when, from some cause or 

 another, instead of merely touching the block gently with 

 the point of the copper, I must have pushed the sloping 

 edge obliquely and somewhat roughly on to the flat top 

 of the block, for, to my surprise, instead of melting a little 

 pock in the surface, the square-edged side of the copper 

 slipped without friction right along the face of the solder. 

 It was a perfectly casual accident, but, under the circum- 

 stances, it caused me a sense of mental shock as I instantly 

 recognised the analogy to the skate. 



The barely hot enough, parallel sharp edge of the 

 copper, pressed and pushed forward on the block, was 

 just able to melt the immediate surface, which completely 

 lubricated the iron on the solder beneath. The then well- 

 known property of the lowering of the melting point of 

 ice under pressure at once presented itself; the shock was 

 the result of the instantaneous reflection that I had never 

 before thought of considering why ice was slippery. 



On trying to remember whether I had ever heard 

 of any attempt to explain the slipperinesss of ice in 

 any way — for I felt at the moment as though every- 



