334 Free Electricity. 
Arr. XX XII.—On Free Electricity ; by Rosert Hare, M. D., 
. Professor of Chemistry in the University of Pennsylvania. 
Practicauty there is a striking difference between the excite- 
ment of an electrified insulated conductor, the prime conductor 
of an electrical machine for instance, and the charge of a coated 
pane or Leyden jar. In the one case diruptive discharge is pro- 
ductive of a comparatively short thick spark, in the other of a spark 
distinguished by comparative length and tenuity. The discharge 
from the pane or jar is productive, for equal surfaces, of a much 
greater shock than could result from a spark ten times as long, 
from the conductor of the machine by which the electricity is 
generated. And yet if the intensity be inversely as the square 
of the striking distance, it must be a hundred times as great in 
the case of the conductor, as in that of the coated surfaces. 
Electricity, as it exists in the conductor, has been called free: 
as it exists about the coated e, has been called simulated or 
disguised. Yet Faraday has alleged “that the charge upon an 
insulated conductor in the middle of a room, has the same rela- 
tion to the walls of that room, as the charge upon the inner coat- 
‘. ” 
