472 Messrs. Haselfoot and Kirkby: Electrical Effects 
pressure-tubing, which could be pinched at D, or through a 
drying vessel B’ and a piece of pressure-tubing, which could 
be pinched at E, into the apparatus represented by fig. 2. 
Fig. 2. 
This consisted of an aluminium cylinder H, 26°5 em. long, 
41°5 mm. internal diameter, closed by ebonite ends into which 
brass tubes G, G! were fitted. To these were fastened by 
means of ebonite plugs two glass tubes L, L’, each of which 
formed a kind of T-piece, the lower branches fitting into two 
removable glass bottles K, K’ containing phosphorus pent- 
oxide. By this means the phosphorus pentoxide could be 
easily renewed without taking the apparatus to pieces. A 
brass wire, of 3°25 mm. diameter, was fastened along the 
common axis of the cylinder and tubes, resting in ebonite 
plugs P, P’, and was connected to one pair of quadrants of 
an electrometer. The apparatus was completed by a piece 
of glass-tubing, fitting into the pressure-tubing H, and fastened 
by elastic glue into a short brass tube soldered into the tube 
G. Platinum wires were fused into the glass-tubing at F, 
and could be connected to the terminals of an induction-coil. 
Thus the gas could be exploded. By alternately pumping 
out the apparatus and filling it with dried hydrogen and 
oxygen the pressure of air in the cylinder could be reduced 
to a fraction of a millimetre. 
The course of an experiment was as follows :—The hydrogen 
and oxygen to be exploded were admitted to the required 
pressure, the pinch-cock E was closed, and the pressure py 
inside the cylinder was read; G and Gi, dividing the insu- 
lations between the cylinder aI and the wire W, were then 
earthed, and the cylinder was charged to any desired potential 
by connecting it to one terminal of a battery, the other 
terminal of which was to earth. The field of force having 
been established, the quadrants connected to the wire W, 
which had previously been earthed, were insulated, and no 
deflexion of the electrometer was observed. The gases were 
then exploded and the quantity of electricity thrown on to 
