6YA' WILIJAM SIEMENS, F.R.S. 395 



linn's round and round with wire ; a single wind would do, but by 

 \viii<liii- six times I repeat the action which would take place upon 

 ilir uin- wire sixfold, and this actiou I expect will be manifested 

 upon a galvanometer-needle with which this frame is connected. I 

 can move the frame about away from the magnetic field and no 

 action is produced on the needle, but when I move the wires into 

 ihr magnetic field, there is an action in one direction, and when I 

 move it out again there is an action in the contrary direction. 

 The current produced in this wire is exactly proportionate to the 

 amount of force which I exerted, and this again is proportionate 

 to the rapidity of the motion and to the intensity of the magnetic 

 field. If the two poles are set very close together, and if the 

 current exciting the electro-magnet is great, the current produced 

 in the induction wires will be great also. Again, if I move the 

 wires through the magnetic field with great velocity I encounter 

 greater resistance, and I shall obtain a still greater result. In fine 

 the mechanical power expended in passing the wires through 

 the magnetic field, is converted at once into electric power or 

 current. 



When the magneto-current had been scientifically proved, it was 

 soon taken advantage of in the construction of the machines of 

 Pixii, of Holmes, and of the Alliance Company, which latter 

 machines were made successful at a very early date in lighting 

 some of the coasts of France, and also of this country. Steel 

 magnets were employed, between the poles of which armatures 

 furnished with coils of insulated wire were made to rotate, when 

 by the inductive action thus produced, alternating currents were 

 set up in the coils, and conveyed to the electric lamp without being 

 changed into a continuous current by means of a commutator. 



The next advance upon Faraday's original conception was an 

 armature by which the inductive action can be multiplied con- 

 siderably. In the Faraday instrument the armature was separated 

 from the magnet by lifting it away from it. In this, which is 

 generally known as the (Werner) Siemens armature, the coil is 

 put upon an H piece of iron, and made to rotate in a magnetic 

 field. There are in the magneto-machine placed or the table 

 steel magnets superposed one above the other, and between the 

 poles of these magnetg such an armature is made to rotate with 

 considerable velocity. You will easily perceive that each time the 



