of the Magnetical Principle in Ferruginous Bodies . 35 7 
only one arrangement to be produced in the magnetisms ; the 
unmagnetic condition being the disorderly position of the mag- 
netisms in each particle. If the third be the correct one, then 
the molecules of the iron must be mobile on the application of an 
external attractive force, and an arrangement of the particles of 
the iron be necessary to the development of the magnetic condi- 
tion. 
In whatever manner the effect is produced, the following ex- 
periments, I conceive, will shew that the magnetic force of any 
bar is the result of the combined and aggregated magnetisms of 
all the individual particles, in the same way that the power of 
the galvanic battery is the result of the aggregate of the electri- 
cities of each pair of plates. These experiments, I may premise, 
were all made with small magnets of 1^ inches long, and lj 1 ^ 
diameter ; and their magnetic force in connection, and in vari- 
ous arrangements, was determined by the deviation produced on 
the compass of the magnetimeter , at the distance of six inches 
from the extremity of the nearest magnet. 
1. I combined six of these wires in a regular series of alter- 
nate north and south poles in connection, so as to form a straight 
line, the nearest position being at the distance of 6 inches, and 
the most remote 15 inches from the centre of the compass. The 
deviation that resulted was 25°. (PI. XI. No. 1.) Then, breaking 
the connection of the series (as in No. 2.), but keeping the 
magnets the same distance from the compass, the deviation dimi- 
nished to 18°. 
2. I next placed the six magnets in a parallel series, all in 
contact (No. 3.), and at the distance of 6 inches from the com- 
pass, when the deviation was found to be 23°, indicating a force 
somewhat less than that given by the first series or battery, al- 
though five out of six of the magnets were, on an average, 
inches nearer to the compass than before, and exerting, conse- 
quently, near thrice the force they were capable of, when in their 
more remote position. The wires being afterwards separated, 
(as in No. 4.), the attraction increased to 26°. 
3. Varying the experiment, the six magnets were formed into 
three parallel series in contact, consisting of two magnets in 
length (No. 5.), the north poles of one series being in contact 
with the south poles of the ether ; the deviation in this case was 
2 
