Have light that is strong enough. Remember that the law of the intensity of light as affected by distance is that at twice the distance from the source of light the light is only one-fourth as strong. Reading just before sunset is risky. One is tempted to go on, not noticing the gradual diminution of light. Save the easiest reading for the evening. Newspapers, as a rule, have neither good print nor good paper. If the eyes have much work to do, finish this kind of reading by daylight if possible, and by artificial light read books, which usually have better type and better paper. In all ways endeavour to favour the eyes by doing the most difficult reading by daylight, and saving the better print and the books that are easier to hold for work by artificial light. Writing is usually much more trying to the eyes than reading. By carefully planning his work the student may economize eyesight, and it is desirable that persons blessed with good eyes should be careful, as well as those who have a natural weakness in the eyes; for it often results that those inheriting weak organs, by taking proper care, may outlast and do more and better work than those naturally stronger, but who through carelessness injure organs by improper use or wrong use. Reading before breakfast by artificial light is usually bad. Many eyes are ruined during convalescence. At this time the whole system is often weak, including the eyes. Still, there is a strong temptation to read, perhaps to while away the time, perhaps to make up for lost time in school work. This is a time when a friend may show his friendship by reading aloud to the convalescent. If one finds himself rubbing his eyes, it is a clear sign that they are irritated. It may be time to stop reading. At any rate, one should find the cause, and not proceed with the work until the irritation ceases. If any foreign object gets into the eye, as a cinder, it is better not to rub the eye, but to draw the lid away from the eyeball and wink repeatedly; the increased flow of tears may dissolve and wash the matter out. If you must rub, rub the other eye. If it be a sharp-cornered cinder, rubbing may merely serve to fix it more firmly in the cornea or the mucous membrane of the inner surface of the eyelid. If it does not soon come out, the lid may be rolled over a pencil, taking hold of the lashes or the edge of the lid. The point of a blunt lead pencil is a convenient and safe instrument with which to remove the particle. Sometimes being out in the wind (especially if unused to it), together with bright sunlight, may irritate the eyes. If after such exposure one finds lamplight irritating, he will do well to go to bed early, or to remain in a dark room.