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, Partea 1Wells and Lilly, 1824 - 246 pagini |
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36 inches focus 44 inches Achromatic Telescope ADAMS on Vision adjust aperture Artists assistance become bright Candlelight centre CHAPTER Colour Common Eye concave glass cornea defect degree distance distant objects distinct vision distinctly Dollond Double Object-glass Double Stars Drury Lane DRURY LANE THEATRE Ears Engraving exactly extremely Eye Glasses Eye-lids feet field of view focal length give half in diameter HERSCHEL Illuminating power inch in diameter inches aperture increased Instrument JESSE RAMSDEN Joint KITCHINER Lamp larger less Light look Magnifying power naked Eye Near-sighted Newtonian nifying power Night observed Opera Glass Optician pair Pancratic Eye-tube Pebbles pencil of rays perfectly PETER DOLLOND Phil proper proportion Pupil Reader REFLECTING TELESCOPES require retina seen seldom Senses sensibility shew Short-sighted Persons Sight Single Object-glass Sir WM sliding tubes soon Spec Spectacle frame Spectacle Glasses tacles Tele Theatre tion Trans WILLIAM KITCHINER