the particles of magnetic bodies , &c. 121 
calculation, founded on that principle, perfectly accord with 
those obtained from experiment; and this, I trust, I have 
done by the preceding experimental and theoretical details. 
Considering this then as an established principle, future in- 
vestigations must be directed to the discovery of the function 
of the time on which the intensity of the induced magnetism 
depends, during the approach of a magnetic pole towards a 
physical point susceptible of magnetism, and also during its 
recess. I have stated what I consider to be not an impro- 
bable law ; but the whole time occupied either in the deve- 
lopement of magnetism by induction, or in its dissipation, is 
so minute, that it appears extremely difficult to devise expe- 
riments that would be a direct test of such laws ; and to the 
more indirect tests, derived from a comparison of such expe- 
rimental results as the foregoing, with theoretical results 
derived from these laws, difficulties of analysis in general 
oppose themselves. 
Royal Military Academy, 
7th June, 1826. 
/ 
MDCCCXXVII. 
R 
