10 



IMPROVEMENTS I\ THE ELECTRICAL MACHINE, 



culars of this improvement; and he soon obtained for me 

 the enclosed paper, wliich I believe, isin the Professor's own 

 hand writing. 1 have made some practical remarks on this 

 paper, which may be useful to electricians, and I have also 

 added a hint of an extraordinary improvement I am about 

 to make in the plate electrical machine. Should you ap- 

 prove these observations, you will oblige me by inserting 

 them in your valuable Journal. 



I am, with due respect, 



Sir, yours &c. 



54, Poland Street, Soho. J. CUTHBERTSON. 



The negative Mr. Cuthbertson's electrical machine is upon the whole 



power not t h e b es t i ever met with. The only fault I found was, that 



equal to the ,.,.,,, , . . , 



positive from insulating the wnole machine, so many inlets were given 



to the fluid, that the negative power of it was by no means 

 owing to the equal to the positive. His winch or handle is an insulating 

 hand passing so one) ]-j U (- }{• pa^ed so near the mahogany pillar twice in every 

 near the pillar , • , n i r- i i it ,, ., 



in r amine the revolution, that a flash was seen trom the handle to the pil- 



winch. lar perfectly risible in the dark, and the effect of which [ 



A glass handle fe'* "early to the shoulder. To remedy this I added a glass* 



nnd disc ad.led handle surrounded l»v a disc about seven inches diameter 

 to prevent this. . c , . ' . , , . , 



and of the same piece with the handle. 



Within the hollow part of the handle was cemented a brass 



conical socket for receiving the steel pin of the former 



wooden handle, and a nut to prevent its coming off. The 



glass disc thus entirely prevented any supply of fluid to the 



Farther altera- machine by the hand. I now perceived however in the dark 



Uou ' a constant stream of the fluid entering by the small brass 



bail and wire, which' supports the silk flaps of the upper 



rubbers. 1 therefore took it away, and supplied its place by 



a solid ^lass rod. 



The negative power of the machine was thu» move than 



doubled, or it charged a vial negatively with less than one 



half of the number of turns it did when I received it. I 



Fdgesand an- indeed still perceived some appearances of lights at times, on 



ftfttof the the- edges and armies of the wood work, but by rounding 



woodwork n , . , , ... 



.round*!. these more, or adding pretty large brass balls contiguous to 



then-.; 



