46 Mr. G. Fuller on a Water-spray Influence-machine, 



The Electrical Action of the Machine. 



An instrument made of only sections I. and IV., with their 

 rings connected with their receivers, as shown above, will 

 charge itself; and the difference of potential of the two re- 

 ceivers may be such that sparks \ inch long may occasionally 

 pass between them, though more usually -§ inch is the longest 

 that can be obtained with a head of water of about 23 feet. 

 With this arrangement, after every discharge the potential of 

 the rings is nearly equalized ; whereas in the machine with 

 four sections, I, and IV. keep up the difference of potential 

 of the rings of II. and III. 



With respect to the action of the machine, the author, 

 whilst giving the considerations from which it was constructed, 

 must leave to the electrician to determine whether they have 

 anything to do with the true explanation of the phenomena. 

 The water, at the point where it is divided into drops by the 

 resistance of the air, is electrified by induction from the rings; 

 the former being in connexion with the earth through the 

 unbroken water of the stream, and the action seems similar 

 to that employed in Sir W. Thomson and Professor Silvanus 

 Thompson's water-dropping accumulators. That such is the 

 case appears to follow from the fact that, if the rings are either 

 placed much above or much below the level where the water 

 breaks into spray, the machine ceases to work. When the 

 rings are at their proper level there is an additional action ; 

 for the particles that are inductively electrified are split up 

 into numberless minute particles, some of which are so fine 

 that they float about in the air and do not fall into the re- 

 ceiver. And it is this breaking up of the water into minute 

 particles that the author thinks may account in part for the 

 effect produced ; for when a number of spheres that have been 

 electrified unite into a mass of less surface, their potential in 

 the latter state is higher than in the former. 



Another point which the author thinks must be taken into 

 consideration is the speed with which the particles move 

 through the ring, as it was only when he experimented with 

 a fall of some feet instead of inches that he obtained a poten- 

 tial high enough to produce sparks. With a very slow speed 

 the attraction of the ring is too strong for the water, so that 

 it at last, as in Sir William Thomson's apparatus, bends 

 against it. That the division of the drops into minute spray 

 plays a part in the action of the machine seems to be shown 

 by the fact that sparks of the same length, in the same state 

 of the atmosphere, have been obtained from it when the ve- 

 locity of the water has been very much diminished. The 

 sparks, as a rule, have not been so numerous per minute, but 



