• A VERY interesting series of experiments may be carried out with chlorine, in the formation of both organic and inorganic compounds of a wide range of application.
ONLY 50 AT THIS UNHEARD-OF PRICE LEFT This combination microphone and headset, built under rigid U.S. government supervision, and designed as a regular intercommunicating telephone system, may be slightly modified to match into a radio transmitter and receiver.
By HUGO GERNSBACK DURING the next few years, we are to witness a series of strenuous competitions between our railroads and the airplanes. Only too late have the railroads awakened to the fact that airplanes are cutting in seriously into their business. Because of the superior speed of the airplane, the railroads which, during the last decade, lost much business to the automobile, are now beset by a new worry.
By JOSEPH H. KRAUS How to Make Money from These Plans OF four items illustrated here, only the "Human Roulette Wheel" requires much work. Three are well fitted for profitable sales, the roulette wheel and the illusion box most so. The track circuit for toy trains is an ideal window display. Sell your services to local toy stores, offering to arrange for them an automatic display which is mysterious and attracts attention. The light twinkler makes an excellent display, but is best for home use.
IN this department are printed letters from readers on various scientific and related topics. It matters not whether your letter is complimentary or whether it is a brickbat, we will publish it just as readily. We want your comments—your opinions—on topics connected with this magazine. No attention will be paid to unsigned letters, nor are letters answered by mail. Worth-while letters are published here every month. Address Editor, Science Forum, EVERYDAY SCIENCE AND MECHANICS, 100 Park Place, New York City. More Radio! Although I am not a subscriber to your magazine, I never miss a copy of it at the newsstands. Your mag is one of the best on the market, and yet there are ways of improving it. To be a radio operator, set builder, service man , or what have you, you must have patience, We, the radio hams of the United States, have been patient long enough while you let the greedy chemists hog all the articles. For the last four or five months I haven't seen a worth-while radio article, while look at those good ones that were published last year.
For Children For Grown-Ups For Professional Use For Business Efficiency ...keeping baby's record...or the family's record...comparing friends' fingerprints... amusing visitors...with this scientific set! The latest fad! Keeping a permanent record of FINGERPRINTS! Made doubly delightful by real, detective-like, elaborate set that gives you all the facilities of Scotland Yard!
s IT is now about a thousand years since the first Chinese rocket engineer tied one of his new go-devils to an arrow and took a shot at the invading Tartars. Perhaps the millennial celebration of that invention will include a shot with a much larger rocket at the moon. However, the present-day rocket experimenters are plugging away steadily, improving details in their equipment, and thinking in terms of thousands of feet of ascent; while the fiction writers glibly describe steering a rocket craft through asteroids and meteor showers, like a taxi through traffic.
BALL lightning, one of the rarest of atmospheric phenomena, has been seen by few people. It sometimes appeared during an electrical storm, in the shape of globes of what seemed to be like flame, a few inches in diameter, moving slowly through the air, and bursting with a loud explosion when they struck some grounded object.
IN the old days, it was supposed that a sharp-pointed object—like a bullet—encountered least resistance in passing through any medium, solid, liquid or gas. The cigar-shape was then the ideal for speed in a balloon, a boat, or a racing car. However, science finally demonstrated that a body with a blunt prow and a long, gently tapering stern is capable of travelling most rapidly and with the least power.
TOY manufacturers in this country have been extraordinarily inventive of late, and have produced a set of new and unusual items differing greatly from the ordinary run. Many of these are illustrated in these three pages; but lack of space permits only a very general description of construction, operation or equipment of some of them. Others are described in the captions beneath the photos. However, if any of the readers are interested in the names of the manufacturers, such information will be furnished free of charge: merely specify the numbers of the items, and the data will be forwarded.
Pneumatic Globe • AN ingenious countryman of Columbus invented the handy device illustrated. A cloth surface carries a fairly detailed view of the earth's surface, on a small scale. A rubber balloon within can be quickly blown up, and again deflated. A portable scale is furnished. Waterproof Case • ONE can take valuables into the water safely in this light metal container. The inner box holds, as shown, smokes, jewelry, and other personal property; the whole fits into a pocket or belt without trouble. It is a Hungarian invention, patented here, though arrangements for its marketing are yet to be made.
Estimates of Universe's Size Vary •IN the latest estimate of the size of the universe, contained in the Smithsonian tables of scientific data, there is considerable latitude. The largest estimate of the mileage, that of Dr. Edwin Hubble, is 190 billion light-years, or 1,140 sextillion miles. The smallest is that of Dr. Willem de Sitter, 76 quintillion miles, or 13 million light-years. The ratio is that between a mile and a third of an inch, or 15,000 to one, between these guesses. At any rate, it's a long walk before breakfast.
MANY attempts have been made, both before and after the invention of the airplane, to develop a craft which should really fly. The ornithopter, or bird-wing craft, has not been successful in its motion, any more than mechanical devices which simulate walking. The bird, like the man, has a great many controls in its muscular equipment, which are difficult to imitate in a machine. However, during the past few years, the idea of a revolving wing has been attracting more and more inventive effort.
The sense of sight is inborn; but the use of eyes, like that of hands, is acquired, and the expertness gained by different people varies greatly. Here are some tests of sight. WE are born with a sense of sight, but we must learn to use it; and there is quite a difference in the way different people interpret the things they see. The first example is the familiar one of the full moon. It seems to cover a fixed angle, which is the same for all observers—at the same time and place, at least. Yet one will tell you the moon looks an inch across; another that it looks a foot across.
“Hellos” by the Millions RECENT figures compiled by the Bell System show that there is more than 145 million miles of telephone wire in the world, or enough to reach from the Sun out past the planet Mars; and about 60% of it is in the United States, where it was used for more than [...]