270 Mr. W. R. Pidgeon on an Influence-Machine. 



think to the fact that the inductors apparently do not lose 

 their charge with each spark, and therefore, at once, start up 

 the action of the machine. 



With a view to decrease the capacity of each sector at the 

 moment of its being discharged into the collector, I put on 

 another set of inductors, one opposite to each of the main 

 collecting brushes, and so arranged matters that they could 

 be charged either from the neighbouring inductor or from the 

 collector itself. In this way each sector at the moment of 

 discharging itself into the collector is almost surrounded by a 

 field of the same sign as itself, and I hoped by this means to 

 squeeze more of its charge out of it as it passed. I was at 

 first, however, disappointed to find that this second set of 

 inductors made little if any difference to the output of the 

 machine, whether they were connected to the other inductors 

 or to the main collectors. But on arranging them to collect 

 their own charge directly from the small knobs on the revolv- 

 ing disks, at a point just before the main collecting brushes, 

 they became of value and increased the efficiency of the 

 machine nearly ^th. 



By the kindness of Mr. Wimshurst and Dr. Lewis Jones I 

 have been enabled to compare the output of my machine with 

 that of a Wimshurst having eight 15-inch plates and also 

 with one having two 16-inch plates. I find that, area for area, 

 and without using the stationary inductors, the efficiency of 

 my machine is to that of the Wimshurst as 3 to 2 ; and with 

 the inductors in use it is as 5*64 to 1. That is, from 5 to 5| 

 times the area of plate is required to pass the collector in the 

 Wimshurst machine to that which must pass it in this 

 machine to produce the same result ; or, to give the figures 

 as we took them together : — 



sq. ft. 



Mr. Winishurst's 8 plate 15-in. diam. machine requires 97-07 



of area to pass the collector per spark. 



Mr. Jones's 2 plate 16-in. diam. Wimshurst requires 87 - 83 



W. R. Pidgeon's 4 plate 24-in. diam. machine^ without inductors . . 63"64 



„ „ „ „ with one set of inductors on 21-117 



„ „ „ „ with both sets of inductors on 17 # 2 



I feel I ought to mention a mistake I fell into, while work- 

 ing on this machine, which nearly made me think that fixed 

 inductors were of no use. When first trying them I used 

 brushes, instead of a single point, to collect their charge, and 

 was disappointed to find the output of the machine reduced 

 to almost nil, because, us I ultimately discovered, the brushes 

 formed a bridge between the sector knobs and allowed the 

 charge to flow back from sector to sector, instead of being- 

 carried forward to the collector. Another difficulty I have 



