Double Axial Reciprocating E'ngine. 141 
form bar, } 6, is joined to one of a similar size and shape, placed - 
at the other end of the sliding frame, cc. They are joined by 
means of brass rods about six inches in length, and of the same 
thickness as the bars of iron, and both are firmly secured by the 
cross heads and sliding rods of the frame, cc. ‘The helices, a a, 
are firmly cemented in a stout casting, d d, which also contains 
the bearings of the sliding rods. The frame is attached to the 
fly wheel f, by the connecting rod e, and crank shaft g, after 
the usual manner. ‘The dotted lines represent the course of the 
wires from the helices underneath the base board, which again 
pass up through it, near the crank shaft, to be connected with an 
electrotome or cut off. This part of the engine will be under- 
stood without further explanation by all familiar with the subject. 
It will be noticed, however, that instead of using a single pair of 
helices upon the U form bar, there are two pairs. This arrange- 
ment makes a great gain of power, for the action upon the bars is 
made consecutively by the helices while the bars are passing the 
strongest points of each. In the machine of one foot stroke, there 
will be four pairs upon each bar, operating consecutively. It is 
obvious that they may be increased in number as the length of 
stroke increases, even up to two feet. I have also availed myself 
of a mode of applying the direct power of the magnet upon a bar 
of soft iron, in conjunction with the continuous action of the he- 
lices; which adds about ten per cent. to the actual power of the 
