Copy 1

The economy of the eyes: : Precepts for the improvement and preservation of the sight. Plain rules which will enable all to judge exactly when, and what spectacles are best calculated for their eyes Observations on opera glasses and theatres, and an account of the pancratic magnifier, for double stars, and day telescopes. / By William Kitchiner, M.D.

  • Kitchiner, William, 1775?-1827.
Date:
1824
Catalogue details

Licence: Public Domain Mark

Credit: The economy of the eyes: : Precepts for the improvement and preservation of the sight. Plain rules which will enable all to judge exactly when, and what spectacles are best calculated for their eyes Observations on opera glasses and theatres, and an account of the pancratic magnifier, for double stars, and day telescopes. / By William Kitchiner, M.D. Source: Wellcome Collection.

    68/268 (page 54)
    first power, or 36 inches focal length, for com- mon purposes ;—12. e. for reading moderately sized prints, and writing in Day-light. His practice has been, from the period of first using Spectacles, never to employ a higher power than was immediately and abso- lutely wanted for the particular occasion,—for which purpose he constantly carries with him Two pair of Spectacles; one pair of 36 inches, and another pair of 24 inches focal length ; the two pair put on together, serving him for a magnifying power of 12 inches focal length for extraordinary purposes. The Two pair of Spectacles are for the con- venience of being carried in the pocket: at Home, in his study, he has by him all the gra- dations of 36, 30, 24, 18, and 12 inches focal length, to be used as required. He observes, that immediately after using Spectacles of a high magnifying power, the Sight does not easily accommodate itself to a lower power; and in such cases, it is neces- sary to give the Eyes a little time to rest and recover themselves. This strain of the Eye, and occasion for