WIND POWER CARLILL. 149 



could be accumulated and utilized in a period of calms. Acting upon 

 this hint, one of Lord Kelvin's pupils, James Blyth (afterwards pro- 

 fessor at Glasgow Andersonian College) made a series of experiments 

 which led to the construction of a very efficient and economical wind 

 motor. Bernoulli and Maclaurin had shown that in theory the most 

 efficient form for a windmill would be a cup or box consisting of 

 half a sphere or half a cylinder revolving in the line of the wind. 

 Robertson adopted this type for his anemometer, the four cups of 

 which are familiar objects at our observing stations. These four cups 

 constitute a body revolving in a resisting medium, and can not ex- 

 ceed a certain limiting speed. In the usual form of anemometer 

 that speed is one-third that of the wind. 



Upon this sound theoretical foundation Professor Blyth saw the 

 possibility of designing a wind motor which would develop more 

 power than the old sails, while it would be more economical in con- 

 struction and free from their defects in working. For the cups of 

 the anemometer he substituted boxes, semicircular in section, which 

 he mounted on arms extending at right angles from the shaft. Using 

 boxes 10 by 6 feet, he found that his motor developed eight horse- 

 power in a very moderate breeze, and, moreover, it justified his ex- 

 pectations in other respects, and could be left free to run by itself 

 in the strongest gales without suffering injury. After using his mill 

 for some years for the purpose of electric lighting, Professor Blyth 

 was sanguine enough to prophesy that before long electric light and 

 power would be supplied over a large part of Great Britain by the 

 use of wind engines on his model. 



Possibly the inventor's early death led to the oblivion which his in- 

 vention has suffered. More probably the neglect is due to our pre- 

 occupation with the ideas of coal and steam, which lead us to con- 

 template any alternative source of power with a smile of derision. 

 We have grown accustomed to regard the hewing and carrying and 

 burning of coal as the first essential of industry and even of life, and 

 have regarded the multiplication of railway sidings with their miles 

 of laden or empty trucks as signs of material prosperity. But the 

 war has opened our eyes on this subject as on others, and in some 

 measure we are prepared for the conclusion that the internal trans- 

 port of coal is a wasteful and disagreeable necessity which in a well- 

 ordered community w r ould be reduced to a minimum. And when, in 

 addition, we are confronted with a rise in price to at least double 

 its pre-war quotation, the question of an alternative source of power 

 which does not need railway transport and storage, and does not 

 require the assistance of highly paid middlemen and brokers, be- 

 comes a question of truly practical politics. There ought, therefore, 

 to be a chance for the element which has so often befriended us. 



136650°— 20 H 



