Volume 2

Magnetical investigations / By the Rev. William Scoresby.

  • Scoresby, William, 1789-1857.
Date:
1839-1852
Catalogue details

Licence: Public Domain Mark

Credit: Magnetical investigations / By the Rev. William Scoresby. Source: Wellcome Collection.

    40/324 (page 120)
    The first and most elaborate investigation— as to the effect of separation on the progressive accumulation of power in the whole mass of plates—was made with interposed discs of 0*14 inch (about one-seventh of an inch) in thickness. As however, the series so separated—like the frame saws in a saw-mill—spread out to the width of several inches (and in subsequent experiments, with thicker discs or blocks, sometimes to the breadth of more than a foot)—it was found con¬ ducive to accuracy to test their powers at two lengths, or four feet distance, instead of one length, as in the former experiments. At the same time, for the advantage of comparison with the results obtained at one length distance, occa¬ sional trials—in the progress of combination— were made of the action of the series on the com¬ pass at one length; which, with other comparative experiments, by means of various combinations and bars of the same length, afforded the means of determining, experimentally, the precise ratio, unequated, of the directive forces for distances of one and two lengths. It may be convenient, perhaps, to give this determination before pro¬ ceeding with the investigation proposed. The following table exhibits a selection of the comparative deviations, at one and two lengths' distance, of different combinations of two-feet plates.