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“ electro-magnet, and from this obtains a second and more 
“ powerful current, which, used in like manner, produces 
“ one still more intense. I, using only a single machine, 
“ pass the currents from its armatures through wires coiled 
“ round the permanent magnets in such direction as to 
“ intensify their magnetism, which, in its turn, reacts upon 
“ the armatures and intensifies the current,” 
Mr, Murray’s warning to inventors against patenting his 
idea would seem to have been disregarded, as a patent was 
taken out on December the 24th of the same year, by C. & 
S. A. Yarley, for “Improvements in the means of generating 
Electricity,” wherein is described a machine consisting of 
two electro-magnets and two bobbins. The bobbins are 
mounted on an axle, on which also a commutator is fixed ; 
the ends of the insulated wire surrounding the bobbins are 
connected with this commutator and through it with the 
insulated wire of the electro-magnets, forming the whole 
into one electric circuit. Before using the apparatus an 
electric current is sent through the electro-magnet for the 
purpose of securing a small amount of permanent magnet- 
ism in the iron core of the electro-magnet. On revolving 
the axle, the bobbins become slightly magnetised in their 
passage between the poles of the electro-permanent magnets, 
generating weak currents in the insulated wire surrounding 
them. The effect of the current passing through the electro- 
magnets is to increase their magnetism, and to magnetise in 
a higher degree the bobbins when passing between the poles 
of the electro-magnets, and the bobbins act and react on 
each other causing the circulation of increased quantities of 
electricity. 
Another patent for the same idea was taken out by C. W. 
Siemens, F.RS., on January the 31st, 1867, as a communi- 
cation from Dr. Werner Siemens, of Berlin. Again the 
same idea was communicated to the author in a letter from 
Mr. Moses G. Farmer, of Salem, Mass., U.S.A., who had 
