668 FRAGMENTS OF SCIENCE. 



machines were introduced with success at Cape la Heve, 

 near Havre; and the Elder Brethren of the Trinity House, 

 determined to have the best available apparatus, decided, 

 in 1868, on the introduction of machines on the Alliance 

 principle into the lighthouses at Souter Point and the 

 South Foreland. These machines were constructed by 

 Professor Holmes, and they still continue in operation. 

 With regard, then, to the application of electricity to 

 lighthouse purposes, the course of events was this: The 

 Dungeness light was introduced on January 31, 1862; the 

 light at La Heve on December 26, 1863, or nearly two 

 years later. But Faraday's experimental trial at the South 

 Foreland preceded the lighting of Dungeness by more than 

 two years. " The electric light was afterward established at 

 Cape Grisnez. The light was started at Souter Point on 

 January 11, 1871; and at the South 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 ob- 

 tained 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 Manchester. There are here sixteen 

 permanent horseshoe 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 disconnected. In turning the handle and causing the 

 armature 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 immediately 

 experience a greatly increased resistance to rotation. 

 Something over and above the ordinary friction of the 

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



