58 
Mr, W. Brande's Lecture on some 
§. IV, 
In the preceding detail of experiments, such only have been 
selected as were attended with marked results. The electrical 
energies of many other substances were examined and com- 
pared, but no new facts were ascertained, nor were any 
circumstances observed which interfere with the inferences 
suggested by the above statement. 
To insure accuracy, each of the experiments was severa]^ 
times repeated in the presence and with the assistance of some 
of my chemical friends, and the results were uniform when 
proper precautions were attended to. It is especially neces- 
sary to operate in a quiet atmosphere, and to employ a feeble 
electrical power, for if the machine is too strongly excited, 
the substances under examination are alternately attracted and 
repelled between the poles, especially if insulated, or non-con- 
ductors of electricity. The balls were usually withdrawn from 
each other to a distance of four inches, and the subject of expe- 
riment placed equidistant between them. The poles too were 
occasionally changed, by moving the connecting wires from 
one ball to the other, with a view to insure correctness by 
observing the change thus produced in the direction of the 
flame or vapour. 
The experiments were sometimes varied, by using the 
Leyden jar with a sliding’ electrometer connected with its 
outer surface: the substance, the electricity of which was to 
be examined, was placed between the ball of the charged jar, 
and that of the electrometer. 
Regarding these experiments, as connected with electro- 
chemical theory, they appear to furnish a more evident proof 
