Seeing color with the eyes closed
Sharon, Conn.
Dear St. Nicholas: Can you please tell me why, when you close your eyes, you see colors? I would love to know.
Yours as ever,
Eleanor Carse.
There are several reasons: (1) Considerable light really passes through the closed lids, as through an egg-shell. Under some circumstances the long waves of the red end of the spectrum would be the only ones which would get through and make an impression upon the retina. (2) Sometimes the color of an object makes a distinct impression upon the retina, but we do not consciously distinguish it unless the eyes are closed, and conflicting color impressions shut off. (3) In some forms of indigestion poisons in the circulation may stimulate the cells of the retina to suggest color—more likely from the violet end of the spectrum. (4) A sudden hard blow upon the head may excite the cells of the retina to the point of suggesting color. (5) Some drugs have the effect of making one see a certain color, and this may persist with the eyes closed—santonin, for example, makes one see yellow. (6) There are other reasons, too, but they would require technical explanation.—R. T. M.
Causes of thunder and lightning
New York City.
Dear St. Nicholas: Would you please tell me what causes thunder-storm and lightning?
Yours respectfully,
Elsie Friedman.
The thunder-storm is caused mainly by the violent upward rush of moist air. As the weight of the atmosphere is greater at the surface of the earth than it is in the higher regions, this moist air has less weight to bear as it rises. It then expands, and the cooler upper air cools it, and condenses some of its moisture into drops of rain. These drops are united, and torn apart again, and so tossed about by the wind, especially by the upward currents that continually arrive, that the rubbing, and tearing, and friction set free what is called frictional electricity. When this process has gone far enough, a sudden discharge of the electricity takes place, and we say, “It lightens.”
The atmosphere along the path of this discharge is violently agitated, and the waves of pressure that travel out in every direction from each disturbed region produce the roar and rumble of the thunder.—Willis L. Moore, Chief U. S. Weather Bureau.
The number of eggs in a quail’s nest
Falmouth Heights, Mass.
Dear St. Nicholas: I would like to know how many eggs there may be in a quail’s nest. I ask you this because 
A quail’s nest. my father found a quail’s nest in the fifth hole of the Woods Hole Golf Course, Woods Hole, Massachusetts. It had fourteen eggs in it.
Your loving reader, Helen F. Smith(age 9).
The usual number of eggs laid by a quail is from ten to eighteen, though sometimes a nest has been known to have as many as twenty-five.
Wheels in moving pictures running backward
Reno, Nev.
Dear St. Nicholas: Please tell me, through “Nature and Science,” why wheels on a wagon in moving pictures appear to be moving slowly the wrong way.
Your interested reader, Paul Harwood (age 13).
In turning the handle of a moving-picture camera to take the first picture, if the operator turns at a very much slower rate of speed than he should, and if the operator of the projection machine, who throws the picture on the screen, turns the handle of his machine at a greater rate of speed, the result will be that the wheels of the vehicle will appear to be turning the wrong way. This is one of the many means that the moving-picture camera man uses to get some of the results seen in so-called trick pictures. For instance, by reversing, they can show people diving or jumping upward, or show a broken tray of dishes come together again and going back into the hands of the person that dropped the tray. Any of the reliable books on moving-picture camera work will explain a number of these apparently mystifying results.—“The Moving Picture World,” J. Wylie.
562
