SPINNING MOVEMENT. 



way by local sources of cold, form systems 

 of circulation known by the name of convection 

 currents, which play a very important part in 

 the natural history of our earth. A good 

 instance of currents of air caused by local 

 cooling is that offered by the windows of a room, 

 in connection with which it will be worth 

 while to explain the paradoxical unfairness 

 of a story not seldom told to the disadvantage, 

 once more, of an elderly gentleman. 



In the days when large clear sheets of plate 

 glass were new and rare, such a gentleman, 

 visiting for the first time in a house furnished 

 with this glass, was seated near a window 

 which had no cross-bars from top to bottom. 

 After a time he clapped his hand to the top 

 of his head, which was not protected by hair, 

 and, his sight also being none of the best, 

 complained that he had caught cold from the 

 draught through the open window. It was 

 explained to him that the window was really 

 closed ; but having imagined that it was open 

 and that he had caught cold from the draught 

 through it, he did, as a matter of fact, endure 

 all the distresses of a bad cold for the next 

 fortnight. This is told as a remarkable instance 

 of the effect of imagination the wonderful 

 power of the mind over the body. He had 

 caught cold from his imagination ! 



The story does not necessarily illustrate 

 any such thing. Although the window was 



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