318 Astronomical and Nautical Collections. 
equal force, particles of the opposite nature: and the law of this 
force, as deduced from direct observation, is such, that it varies in 
the inverse ratio of the squares of the distances, the same law that 
governs the Newtonian attraction, which seems to prevail with re- 
gard to all the actions of bodies that are sensible at great dis- 
tances. Setting out from this hypothesis, they have determined, 
by mathematical analysis, the distribution of the electricity at the 
surface of conducting bodies, the electrical pressure which takes 
place, from within to without, at every point of this surface, and 
the action of the electric stratum which envelopes it on any given 
point of space. The results of such calculations have been found 
in perfect conformity with the numerous experiments made by 
Coulomb on this subject about forty years ago, [as well as with the 
still earlier experiments of the late Lord Stanhope, and of Mr. 
Cavendish, and with the subsequent experiments of Professor 
Robison, and others;] and at present this part of the science of 
electricity, which relates to the equilibrium of the two fluids at 
rest, abstracted from the proper action of the substance of the elec- 
trified bodies, is theoretically complete ; or at least it presents us 
only with such analytical difficulties, as depend on the form and 
the number of bodies subjected to each other’s mutual influence. 
From the analogy of the phenomena of magnetism with those of 
electricity, it was natural to attribute also the attractions and re- 
pulsions of magnetic substances to two imponderable fluids, a 
boreal and an austral fluid ; and Coulomb inferred from his expe- 
riments the same law of inverse proportion of the square of the 
distances for magnetic as for electrical forces. The proofs, how- 
ever, which he has adduced in support of this law, as far less con- 
clusive for magnetism than for electricity, although there is still 
reason to admit its truth, so far as it may be confirmed by the 
agreement of calculations, rigorously derived from it, with actual 
experiment. 
Besides the analogy of the law of the forces, there is another 
point of resemblance in the theories of magnetism and of electricity 5 
that is, the distinction of bodies into two classes with regard to the 
greater or less degree of permanence with which they retain any 
