162 Scientific Intelligence. [Fes. 
error may be rectified, can we doubt that evil may be produced 
thereby? All this may probably be rectified by simply suspending 
the glass as a compass, so as uniformly to maintain its perpendicular 
position. This, like the former, is a case to be determined by 
practical observation, although theoretically we may deem it true. 
VIII. Improvement in the Plate Electrical Machine. By the Same. 
In the plate electrical machine, eyery one has probably at times 
found the inconvenience of the usual form of the arms of the 
prime conductor, which pass on each side of the glass to collect the 
fluid. There is moreover, without proper care, some danger 
perhaps of breaking the glass in removing the conductor ; and in a 
variety of ways it is troublesome. I made some short time ago 
what I consider as an improvement in this part of the apparatus, 
especially as it can be adapted to every sized plate. It consists 
simply of a glass rod standing firmly in a loaded foot, on the top of 
which a cap is fitted of brass, ending in a ball, perforated laterally 
through the middle. Through this opening a brass rod passes, and 
is bent on each side, forming two parallel arms about two inches 
apart. This rod (the arms of it) moves up and down in the opening, 
but may be fixed at any angle by a small screw at top of the ball. 
The inner side of the arms are provided with points about half an 
inch long. Now one of such is placed near each edge of the glass 
plate, and the arms being moved to the requisite situation, the 
small screw fixes them by pressing upon the rod. From one of the 
arms, or from the cap or ball at top, a chain passes to the prime 
conductor, which may thus be suspended from the ceiling by silk, 
or fixed in any convenient mode. It is evident that, from the 
motion of the arms, it may, if made of a good size, be fitted to 
use as well in a small as a large machine; and when not used, the 
arms may be allowed to drop laterally, and occupy a very small 
space in the case for the machine. The following rough sketch will 
explain the above to your comprehension. 
A (Plate XLUI. Fig. 4) represents the machine with the arms 
shut laterally as placed in case ; B, the machine as placed in its 
relative position on one side of the glass plate, a; J, a chain to 
communicate with the prime conductor, placed in any convenient 
situation. 
Having tried the above, I can really testify to its utility, and 
think it is a very considerable improvement and simplification of 
this part of the electric machine. It can be set up or removed in 
an instant; and, being unconnected with the conductor except by 
the chain, this last may be removed to any distance or situation, so 
as to guard against accident or danger. 
IX. Use cf Galvanism as a Telegraph. By the Same. 
I observe in one of the volumes of your Annals of Philosophy a 
proposition to employ galvanism as a solvent for the urinary cal- 
culus, but which has been very properly, I think, opposed by Mr. 
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