Wisconsin State Agricultural Society. 95 
3. The particles of each one of these fluids attract those cf the 
other with a force varying according to the same law. 
4. Each of these fluids pass freely through some bodies and 
very imperfectly or not at all through others. The former are 
called conductors, the latter non- conductors. 
5. When these two fluids exist in equal quantities in the same 
body, or when they are so united that their mutual attractions and 
repulsions are neutralized, there are no indications of electrical ac¬ 
tion, and the body is then said to be in its natural state. 
6. By friction and other processes, these fluids may be separated 
and accumulated in different bodies. Then electrical action is ex¬ 
hibited. 
7. When a body has an excess of one of the fluids it is said to be 
positively electrified , when it has an excess of the other it is said to 
be negatively electrified. This excess of either fluid is called f ree elec¬ 
tricity. It is to this free electricity that all electrical phenomena 
are due. 
In adopting this theory in regard to the nature of electricity, we 
would not be understood as asserting its absolute truth. Its value 
does not depend on this. If it furnishes,in exact andintelligable 
language, an expression of all the phenomena of electricity; if all 
the logical deductions from it are in strict accordance with observed 
facts, so that we are enabled by it to predict the form and time of 
their occurrance, it has the same value to us as though it were 
absolutely true in all that it assumes. 
Having then a general law or theory by which, on mechanical 
principles we can anticipate and explain all phenomena of common 
or frictional electricity, we proceed to give some of the more impor¬ 
tant deductions, and especially those intimately connected with the 
subject under consideration. These deductions can all be verified 
by experiment. 
Electrical phenomena belong to two general classes: 1 , Statical 
Electricity: 2, Dynamical Electricity. The first relates to the phe¬ 
nomena of electricity at rest , the second to those of electricity in 
motion. 
STATICAL ELECTRICITY. 
Let us first turn our attention to some of the more simple phenom¬ 
ena. By friction or other processes, all bodies may become excited ; 
