I9II] A CURIOUS ILLUSION 239 



snowfall. A new pair of sealskin overshoes for ski made by 

 Evans seem to be a complete success. He has modified the 

 shape of the toe to fit the ski irons better. I am very pleased 

 with this arrangement. 



I find it exceedingly difficult to settle down to solid work 

 just at present and keep putting off the tasks which I have set 

 myself. 



The sun has not yet risen a degree of the eleven degrees 

 below our horizon which it was at noon on Midwinter Day, 

 and yet to-day there was a distinct red in the northern sky. Per- 

 haps such sunset colours have something to do with this cold 

 snap. 



Friday, July 7. — The temperature fell to -49° last night — 

 our record so far, and likely to remain so, one would think. 

 This morning it was fine and calm, temperature —45°. But 

 this afternoon a 30-mile wind sprang up from the S.E., and the 

 temperature only gradually rose to —30°, never passing above 

 that point. I thought it a little too strenuous and so was robbed 

 of my walk. 



The dogs' coats are getting pretty thick, and they seem to 

 take matters pretty comfortably. The ponies are better, I think, 

 but I shall be glad when we are sure of having rid them of their 

 pest. 



I was the victim of a very curious illusion to-day. On our 

 small heating stove stands a cylindrical ice melter which keeps 

 up the supply of water necessary for the dark room and other 

 scientific instruments. This iron container naturally becomes 

 warm if it is not fed with ice, and it is generally hung around 

 with socks and mits which require drying. I put my hand on 

 the cylindrical vessel this afternoon and withdrew it sharply with 

 the sensation of heat. To verify the impression I repeated the 

 action two or three times, when it became so strong that I loudly 

 warned the owners of the socks, &c., of the peril of burning to 

 which they were exposed. Upon this Meares said, ' But they 

 filled the melter with ice a few minutes ago,' and then, coming 

 over to feel the surface himself, added, ' Why, it's cold, sir.' 

 And indeed so it was. The slightly damp chilled surface of the 

 iron had conveyed to me the impression of excessive heat. 



There is nothing intrinsically new in this observation; it 

 has often been noticed that metal surfaces at low temperatures 



