Short sight in relation to education : an address delivered to the Birmingham Teachers' Association, November 2nd, 1880 / by Priestly Smith.
- Smith, Priestley.
- Date:
- 1880
Licence: Public Domain Mark
Credit: Short sight in relation to education : an address delivered to the Birmingham Teachers' Association, November 2nd, 1880 / by Priestly Smith. Source: Wellcome Collection.
Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)
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![to tlie square of tlie distance between the burners and tlie desks. For exain])le, if a burner wbicb bangs at a height of twelve feet above the desks is lowered to a height of six feet, the light enjoyed by the scholars is increased tliereby, not twofold merely, but fourfold. And moreover, light which issues from a central source must fall in wrong directions in certain parts of the room. The desks should be illuminated by a row of burners placed not many feet above them, and somewhat to the left. Ground glass globes, which greatly diminish the intensity of the light, should be replaced by transparent chimneys for the sake of clearness and steadiness; and reflectors may be added with great advantage. Under certain circumstances the reflectors may play the part of screens also, to prevent the light from falling in unfavourable directions. Our second requirement related to the nature of the objects looked at. Within certain limits objects are distinguishable in proportion to their size. If a given type is legible at 24: inches from the eye and no further, a type of half that size will be legible at 12 inches and no further. Again, objects are distinguishable in pro- portion as they form a contrast with the surface on which they stand. Black letters on a white ground are legible at a greater distance than similar letters on a grey or yellow ground. Bearing always in mind that our object is to prevent undue approximation of eye and book, it is obviously desirable that school books should be printed in type of good character and size, and upon paper of a good white and of a sufficient thickness to conceal the letters on the other side of the leaf. I have before me the very extensive works of a well-known writer, complete in one volume, which is sold for a shilling, subject to a liberal discount. The type is](https://iiif.wellcomecollection.org/image/b21637453_0030.jp2/full/800%2C/0/default.jpg)
