THE ELECTRIC LIGHT. 429 



Foreland on January 1, 1872. At the Lizard, which 

 enjoys the newest and most powerful development of the 

 electric light, it began to shine on January 1, 1878. 



I have now to revert to a point of apparently small 

 moment, but which really constitutes an important step 

 in the development of this subject. I refer to the form 

 given in 1857 to the rotating armature by Dr. Werner 

 Siemens, of Berlin. Instead of employing coils wound 

 transversely round cores of iron, as in the machine 

 of Saxton, Siemens, after giving a bar of iron the proper 

 shape, wound his wire longitudinally round it, and 

 obtained thereby greatly augmented effects between 

 suitably placed magnetic poles. Such an armature is 

 employed in the small magneto-electric machine which 

 I now introduce to your notice, and for which the 

 institution is indebted to Mr. Henry Wilde, of Man- 

 chester. There are here sixteen permanent horse-shoe 

 magnets placed parallel to each other, and between 

 their poles a Siemens armature. The two ends of the 

 wire which surrounds the armature are now discon- 

 nected. In turning the handle and causing the arma- 

 ture to rotate, I simply overcome ordinary mechanical 

 friction. But the two ends of the armature coil can be 

 united in a moment, and when this is done I immedi- 

 ately experience a greatly increased resistance to ro- 

 tation. Something over and above the ordinary fric- 

 tion of the machine is now to be overcome, and by the 

 expenditure of an additional amount of muscular force 

 I am able to overcome it. The excess of labour thus 

 thrown upon my arm has its exact equivalent in the 

 electric currents generated, and the heat produced by 

 their subsidence in the coil of the armature. A portion 

 of this heat may be rendered visible by connecting the 

 two ends of the coil with a thin platinum wire. When 



