Defects of sight and hearing : their nature, causes, prevention, and general management / by T. Wharton Jones.

  • Jones, Thomas Wharton, 1808-1891.
Date:
1859
Catalogue details

Licence: Public Domain Mark

Credit: Defects of sight and hearing : their nature, causes, prevention, and general management / by T. Wharton Jones. Source: Wellcome Collection.

Provider: This material has been provided by the National Library of Medicine (U.S.), through the Medical Heritage Library. The original may be consulted at the National Library of Medicine (U.S.)

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    imitated in artificial light, which is usually either too ooa- oentrated or too weak and aneqnal and flickering in com- parison. And then in respect to quality, what a difference IS there to the eyes between Working in the dear oolorleSS light o[' day and the dingy red and yellow light obtained by combustion ! Our own natural feelings—a good monitor to tic guided by in regulating the quantity and quality of the light to which the eyes are exposed,—warn us that work at all try- ing to the sight is best done by day. And to have day- light as long as possible for our work, we should follow tin; primitive fashion of rising with the sun. Work requiring exertion of the vision may lie done hy artificial light. Students and others, therefore, who have to read and write much, should read by day and write in the evening. In like manner, seamstresses should do fine and dark-colored work by day and coarser and lighter colored work by can- dle-light. The window by which we read, write, draw, sew, or do other such work should look towards the north rather than towards other directions. And the desk or work-table should be so placed that the light from the window may fall obliquely from behind and over the left shoulder on the book, paper, or work. By this arrangement the light does not fall directly into our eyes, nor is it reflected di- rectly back from the object into them. We ought never to exert the sight with the sun shining on the work. As working in too weak a light is as injurious to vision as working in too strong a light, we must not continue poring over the book or seam when the light of day fails so