352 Dr. L. Bleekrode on Electromachines 



tried to get the machine active, by one of the methods men- 

 tioned above, without this conductor ; but it remained no 

 longer charged as when the exciting cause (the hand or the 

 ebonite rod) was present : the apparatus would never continue 

 its action till the diametral conductor was applied ; and the 

 action ceased on its removal. 



This property may be used to show, in a very satisfactory 

 manner, that the quantity of electricity that the double electro- 

 machine yields is really doubled. When one of the diametral 

 conductors is removed, then the disk before which it was 

 placed becomes as completely inactive as when it was taken 

 out of the apparatus. Now, for instance in half a minute, by 

 using two rotating disks, as many as 40 sparks (5 centims. in 

 length) appeared between the electrodes ; and after removing 

 one of the diametral conductors almost exactly 20 sparks only 

 were obtained. To get the machine active when the horizontal 

 conductors were brought into contact, and without the inclined 

 conductor, was impossible, because it always requires this 

 piece ; and experience confirms this ; yet the machines with 

 glass disks are easily charged in this way. I have not suc- 

 ceeded in accounting, in a quite satisfactory manner, for the 

 remarkable behaviour of the diametral conductor in connexion 

 with ebonite machines, which, as will now be clear, is quite 

 the contrary of that with glass disks. The following remarks, 

 however, may be made. When the ebonite machine is excited 

 by placing an electric ebonite rod before one of the paper 

 armatures, it is certain that, in consequence of the extremely 

 bad conductivity of the material used, the induction through 

 the disks on the points of the horizontal conductors will 

 be very difficult to set in action, and that it is more advanta- 

 geous, in order to excite the machines, to hold the electric 

 body immediately before the points of the diametral con- 

 ductor, which then charges the rotating disk with the two 

 electricities. These, in turn, act by induction on the card 

 points of the armatures ; and in this way the apparatus is 

 rapidly charged. 



But the same might be supposed to take place without the 

 diametral conductors, by means of the points of the horizontal 

 conductors, when in contact with another ; and a feeble action 

 at least might be expected. This is really the case with the 

 double electromachine when glass disks are used ; - it does 

 not, however, become active so rapidly as in the ordinary way. 



The theory which would account for this property of the 

 diametral conductor in ebonite machines is yet a desideratum. 



Action of the ebonite machine when rotating in an abnormal 

 direction. — The ebonite machine of the first species possesses a 



