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.

    58/324 (page 138)
    power was yielded by the heating of the middle of the plates, and some increase beyond the original power, though not to the same extent, was produced by a corresponding heating of the plates from end to end. This discrepancy with the results previously obtained, having occasioned some embarrass¬ ment and misgiving as to the correctness of the principle I had considered certain, — namely, as to the advantage of an equable hardening throughout for bearing the tension of powerful combinations of magnetised bars or plates,— I sought to verify the newly obtained result, or to determine the cause of the apparent discre¬ pancy, if not real, by a trial of the same pro¬ cess with a set of larger, and, proportionally, thinner plates. For this purpose I selected a set of six plates of two feet in length (that of series E referred to at page 104), and reduced the temper in the middle of each plate, leaving about three inches in length, at each end, in its original state. This was done in the same manner and proportion as in the first alteration made in the temper of the smaller plates, just spoken of, and by which treatment the most considerable increase of power in these plates had been yielded. The change which took place in the power of each plate by this alteration of temper, as ascer-