Mr. Watkins on Electro-magnetic motive Machines, 191 



object being the practical application of electro-magnetic at^ 

 tractive force, and one of them supposed he obtained a power 

 equal to that of half a man. I refer your readers for an 

 account of their labours to Part IV. of Mr. Taylor's new 

 and highly useful quarterly publication, entitled '* Scientific 

 Memoirs." The public have also been recently favoured 

 with notices of a small electro-magnetic machine, said to per- 

 form wonders, on the other side of the Atlantic ; but in spite 

 of the talent already brought into play, it must be acknow- 

 ledged that it is yet reserved for some happy genius to hit 

 upon the right arrangement which shall economically employ 

 this electro- magnetic power on a sufficiently large scale to be 

 used with the desired success. 



In the August number of your valuable Journal for 1835 

 (Lond. and Edinb. Phil. Mag. vol. vii., p. 107,) you favoured 

 me by noticing an arrangement of the electro-magnetic mo- 

 tive machine which I had then contrived. This machine, 

 like all others that I am acquainted with, was founded upon 

 the fundamental principle of Professor Henry's, namely, that 

 of varying at a particular period the polarity of the trans- 

 ient electro-magnet, thus obtaining a succession of magnetic 

 attractions. It is true that Henry only obtained an alternate 

 rectilinear motion, while his followers succeeded in producing 

 continual rotatory motion; still the principle remained the 

 same. 



Henry's principle being universally adopted, it is clear that 

 all those who attempted to carry out the idea of obtaining a 

 motive power by this principle are only entitled to the credit 

 of those modifications of the arrangement which may emanate 

 from their mechanical ingenuity, and to such credit only do I 

 aspire in the present communication on my machines, which 

 I will now describe. 



Fig. 1. (Plate IV.) is a representation of a working model 

 of an electro-magnetic motive machine ; «, «, «, a, are four 

 vertical cylindrical permanent steel magnets suspended by two 

 mahogany cross stages Z>, Z>, which are themselves upheld by 

 two mahogany columns c, c. The electro-magnets d^ </, and 

 iV^ d\ are arranged horizontally, and are attached to and sup- 

 ported by a metal vertical shaft very free to move. Hollow 

 magnets would be lighter, and perhaps answer as well. e,e^ are 

 two wooden cisterns, each with two concentric troughs, and 

 each trough divided into four parts. In the bottom of each 

 of the partitions in the top trough, a short metal wire enters; 

 all these short wires are properly connected with^y,' which 

 are two main wires descending and connecting the battery 

 current with the mercury in the partitions. A similar dispo- 

 sition of short wires is made with the partitions of the troughs 



