. Good and bad eyesight : and the exercise and preservation of vision. und in theory, andlikely to be injurious in practice. I have no fear ofviolet rays in their due proportion; but I should havegreat fear of the consequences of continuous applicationof the eyes by the light, or rather by the semi-dark-ness, which would be afforded by the use of tallow-candles. Whatever kind of light is employed, considerationwill be well bestowed upon the form of the lamp; andthe best form, for all purposes of table work, is thatshown in Fig. 48. Lamps of this description, withcommon Argand burners for colza
. Good and bad eyesight : and the exercise and preservation of vision. und in theory, andlikely to be injurious in practice. I have no fear ofviolet rays in their due proportion; but I should havegreat fear of the consequences of continuous applicationof the eyes by the light, or rather by the semi-dark-ness, which would be afforded by the use of tallow-candles. Whatever kind of light is employed, considerationwill be well bestowed upon the form of the lamp; andthe best form, for all purposes of table work, is thatshown in Fig. 48. Lamps of this description, withcommon Argand burners for colza oil, have been for NATURAL AND ARTIFICIAL ILLUMINATION. 215 many years largely manufactured by a maker namedStobwasser, of Berlin;. and they were imported intothis country, under the name of Queens Reading-Lamps, by several tradesmen, some of whom attachedtheir own names to the lamps they sold, and chargedfor them at a rate greatly in excess of their the last ten years I have seen these lamps,made by the same maker, and identical in every respect, offered for fifteen shillings at one shop and for twopounds ten shillings at another, the two shops beingscarcely five hundred yards apart. They are now madewith Silber burners, and the same construction is easilyadapted to gas. Besides the convenience of being ableto raise or lower the burner at pleasure, they are recom-mended by their hemispherical shades, which are usu-ally of glass, either white, or dark green with a whitelining, the latter being for most uses to be preferred. 2l6 EYESIGHT. All who work by lamplight should have the flame cov-ered by a shade of this or of some similar eyes are instinctively raised at every pause in theoccupation; and then, if there be no shade, they areraised to encounter an increased degree of illumina-tion, because, whatever form of light is used, it is mani-fest that we receive less of it by reflection from /thesurface at which we are looking than if we- look
Size: 1140px × 2192px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, booksubj, booksubjecteye, booksubjecteyediseases
