the particles of magnetic bodies , &c. 81 
distances from the axis, by increasing the numbers in Table 
III. in the inverse ratio of those distances, or by increasing the 
values of » in Table II. in the inverse ratio of the squares of 
the distances. 
Table IV. 
Distance of the Axes of 1 
the magnets from the > “ 
Axis of rotation - ' 
Inches. 
4*2 
Inches. 
37 
Inches. 
3-2 
Inches. 
2-7 
Inches. 
2-2 
Inches. 
*7 
Intensity of the induced ") _ 
magnetism - - f — 
680-5 
I 544 ' 1 
2639-6 
3540-3 
4048-8 
3806*4 
It therefore appears from these experiments, that the in- 
tensity of the induced magnetism would have been the 
greatest had the magnets revolved at the distance 2-07 inches 
nearly ; that is, so that their axes had been at the distance of 
half the radius of the disc from the centre. This is what we 
might expect, whatever may be the law according to which 
magnetism is developed in each particle ; but the great dimi- 
nution in the intensity when the magnets revolved under the 
edge of the disc, leads to an inference respecting the deve- 
lopement of magnetism by induction by no means unim- 
portant, viz. that continuity is much more essential than mass ; 
and that, although a certain portion of magnetism is deve- 
loped in each particle separately, yet the whole of this is 
considerably less than that which appears to accumulate by 
the mutual action of particle upon particle ; for which action 
continuity appears to be requisite. 
The measure of the magnetism developed in the copper, if 
the magnets revolved at the distance 2-1 inches from the axis 
of rotation, would, interpolating roughly from the results in 
Table IV. appear to be 4182 nearly; so that 2091 would 
MDCCCXXVII. M 
