TECHNICAL INDEX AND GLOSSARY 



wheel is a lever of the first class, of which the axle constitutes 

 the fulcrum. See "Wheels and Pulleys," Vol. VI, p. 32. 



Windlass. A modification of the wheel and axle, consisting 

 of a cylinder rotating on an axis propelled by a long handle, or 

 handles, a rope or chain being wound about the cylinder. It 

 is a lever of the second class, the axle representing the fulcrum. 



Windmills. Machines utilizing the pressure of the wind as a 

 motive power. The usual type of windmill consists of a series 

 of inclined planes, each of which forms one of the radii of a 

 circle, or spokes of a wheel, to the axle of which a gearing is 

 adjusted by which the power generated is utilized. Windmills 

 seem to be of comparatively recent origin, as there is no authen- 

 tic record of their use prior to about noo A.D. See "The Work 

 of Air and Water," Vol. VI, p. 62. 



Wind. Air naturally in motion at the earth's surface. All 

 winds come under the influence of the earth's rotation in such 

 a way as to be deflected from their course, and hence take on 

 a gyratory motion. See Vol. Ill, p. 200. 



Wireless Telegraph. In the modern sense, an electric tele- 

 graph which utilizes electro-magnetic waves ("Hertzian waves") 

 in the ether in place of wire, or other conductors, for sending 

 and receiving messages. There are several other methods of 

 using the electric current besides this, but none that are effective 

 for long distances. See "Wireless Telegraphy," Vol. VIII, p. 47. 



Wireless Telephone. A telephone which utilizes Hertzian 

 waves in the ether in place of wire conductors of the electric 

 current. The first practical wireless telephone system was the 

 invention of Dr. Lee DeForest, an American, which was ex- 

 hibited publicly in 1907. See "The Wireless Telephone," Vol. 

 VIII, p. 88. 



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