DETAILS OF THE EXPERIMENTS ON THE INTENSITY OF THE MAGNETIC FORCE,

ADVERTED TO IN APPENDIX No. IV., B.

THE object of these experiments is to ascertain the intensity of the magnetic force, which is different at different places, varying with the observer's distance from the magnetic pole. It is ascertained by noting the number of vibrations, in a given time, of a magnetic needle suspended by a silken fibre. Though I can vouch for the correctness of my observations, I fear they will, nevertheless, prove but of little service to science, the needles being, in regard to the intensity of their magnetic force, very variable.