MANY people ask why POPULAR SCIENCE MONTHLY has such power to attract and hold the interest. Perhaps the answer is that service is its underlying policy. In every field of human activity, every day in the year, science, in some way, serves us.
IF THE proposed transpolar flight by airship is. completed successfully, almost the last unexplored region of the earth will have been charted and mapped. In the restless wanderings of man over this globe only a few square miles have been left untrodden.
THE march of science into the frozen expanses of the Far North is bringing a new era of rapid communication across the wildernesses of snow. Mail planes equipped with landing skis, and swift, motorized sleds soon may replace the picturesque dog teams, just as the motor car is replacing the camels of the desert.
SCIENCE has stormed successfully the last bulwark of Nature in the United States. A few weeks ago an exploration and surveying party of the United States Geological Survey, headed by Col. C. H. Birdseye, completed the work of surveying and mapping the Colorado River through the Grand Canyon—a 450mile swirling stretch of the wildest water in the world.
Supersensitive Microphone Designed to Perfect Radio Broadcasting Holds Fascinating Possibilities for Scientific Research
Perfect Radio Reproduction
How the Sounds Are Detected
WHEN you listen in on the radio to a violin selection or a piano solo, your ears and your memory tell you that what you hear does not sound exactly like the tones of any violin or piano you ever have heard. The sounds that come to you through your headset or loudspeaker approximate those of the instruments, but you would have little difficulty in distinguishing the sounds of a real violin or piano from the radio reproduction.
IN A small city of the Middle West that I have occasion to visit now and then are two drug-stores. One of them has been established for many years. Its proprietor is an excellent pharmacist. That I know from ' experience. The other is a new store— about three years old.
INSECTS possess distinct and varied facial expressions, ranging from what appears to be smirking amiability to gloating frightfulness, yet any attempt to judge their true character from their faces is futile. The terrifying expressions undoubtedly are protective measures endowed by Nature.
PIPING coal from the mine directly into industrial furnaces, as electric power and gas now are delivered from a central station to consumers, may seem like a wild flight of fancy; yet that is what fuel experts say may be seen in the future as a result of recent developments in the use of pulverized coal—the world’s newest fuel.
Prize Contest Winners Find Happiness in Useful Relaxation
A FEW years ago, if some one had asked me whether I had a hobby, I should have been at a loss for an answer. I did not start out to develop a hobby. It just came about in a natural way. I am in the sheet-metal business, and often had thought I should like to make something out of the ordinary—something that would tax my ability as a sheet-metal worker to the limit.
Every Headache a Warning from Your Bodily Machinery
Aches of Sympathy
Find the Causes
Ten Reasons Why Your Head Aches
The Poison of Fatigue
Fresh Air Needed
Time for Repairs
Eyestrain a Cause of Headaches
Danger Points of the Year
A False Argument
Edwin F. Bowers
YOU are the operator of one of the most elaborate and most important machines in the world. Its working depends on many small parts, any one of which, if out of order, will impair the efficiency of the whole. That machine is your must see you through life.
A NEW species of fish that is brilliantly illuminated and that makes a loud shouting noise when chasing smaller fishes has been discovered in the waters of Monterey Bay, Calif., according to Dr. C. W. Greene, of the University of Missouri. Its ability to shout is due to the peculiar construction of its swim bladder, he says.
STRAW soon may be lighting the farmer’s house, cooking his meals, substituting for coal in winter and even running his automobile. The United States Bureau of Chemistry has discovered a practicable method by which a ton of sun-dried wheat straw is said to yield 10,000 cubic feet of illuminating gas, 10 gallons of tar, and 625 pounds of carbon residue, which is an excellent fuel.
DYNAMITE that can be manufactured cheaply from sawdust has been invented by Prof. William M. Dehn, University of Washington, Seattle. He claims it will insure farmers of the Pacific Northwest a permanent and inexpensive medium for blasting stumps from logged-off lands.
WHERE the Gulf Stream and the iceberg-laden Labrador Current meet off the Grand Banks of Newfoundland, extreme differences in the temperature of the sea water often are observed over short distances. This dividing line is known as the “cold wall.”
RUSTING of iron and steel costs the United States about $3,000,000,000 a year, according to a report recently made by J. Vipond Davies, president of the United Engineering Society, based on researches extending over a period of 12 years. Investigations revealed that sea water, water in alkaline coils, or water percolating through “fills” containing some kind of chemical wastes are the most common assailants of iron.
THE food value of gelatin is far greater than is realized generally, according to the announcement of chemists of the Mellon Institute of Industrial Research, University of Pittsburgh, who recently completed a scientific investigation of the subject.
IF IT were possible to inclose a man so that while he could breathe, no heat could escape from his body, he would die quickly. Such is the announcement of Dr. T. H. Read, supervising mining engineer of the Department of the Interior, and F. C. Houghton of the American Society of Heating and Ventilating Engineers, who have completed an investigation of effects of heat on the body.
To MOST of us the fun of hunting a house we can call our own is like the fun of going fishing, of sitting by an open campfire, or of hiking through unfamiliar country—it seems to be born in our flesh. In my time I must have explored at least a thousand houses from garret to cellar.
How to Build a Loudspeaking Three-Tube Radio Receiver
The Ideal Circuit
Winding the Tuning Elements
The Special Tuner
Method of Tapping Coils
Ratios of Transformer Windings
Connecting the Secondary Winding
WHAT is the ideal three-tube receiver for home construction? This question has called forth volumes of letters from radio fans who like to build their own sets and to experiment with various types of instruments. It is generally conceded that a receiver, to be efficient, must be a good distance-getter, simple to operate, with loudspeaker volume on distant stations.
British Inventor Applies Pendulum Principle in New System
GEARSHIFT transmission for automobiles may be made obsolete within a few years by a revolutionary new invention that connects the engine with the driving wheels without the use of any gears whatsoever. It is the work of George Constantinesco, a distinguished British engineer.
How to Get Greater Power from Your Car with Less Fuel
More than Luck
Ten Ways to Save Your Gasoline
Let Well Enough Alone
Adjusting the Points
F. A. Platte
RETURNING from an 1100-mile motor tour not long ago, I chanced to tell a friend that I had the tank filled only four times while a in other words, that I had used about 60 gallons—approximately 18 miles to the gallon. “Do you expect me to believe that?” he demanded.
JACK-KNIFE whittling, which for a time appeared to be one of the lost arts, is coming back. Time was when every American man had a jack-knife and knew how to use it. This skill, acquired through long practice, stood him in good stead in many emergencies throughout life.
UP IN Quebec, the home of the French-Canadian, the habitants still order their lives very much as did their fathers before them and, if need be, make their own furniture. It is one of these pieces of furniture, a chair (Fig. 1), that I shall describe.
MANY simple, time-saving suggestions for machinists are contained in this article, based upon shop ideas developed and used by F. J. Wilhelm, production manager of a Cincinnati firm manufacturing automobile accessories, and Joe V. Romig, machine tool designer and builder.
THIS fixture is useful in shops where contract work is done, especially where nuts have to be manufactured in quantities. Machinists are well acquainted with the procedure of making nut blanks on the screw machine, either automatic or hand; this tool is for tapping the nuts after they are drilled and cut off the bar.
UNTIL his work increases sufficiently to warrant the purchase of an expensive valve-grinding machine, the owner of a small garage can make at low cost a very satisfactory machine of his own, as illustrated. Fig 1. Top view of the valve-grinding machine that utilizes a small tool grinder the grinder in place.
Inserted Scales Give Added Usefulness to Surface Plate
A METHOD of improving the most important tool in the shop—the surface plate—is shown in the accompanying illustration. The word “important” is used advisedly, as all accuracy in dimensions must start from the surface plate. A toolmaker’s square is used against the left-hand edge of the conventional surface plate.
FOR straightening automobile front axles, an accurate gage can be made quickly from four cones and two rods. The cones, which are turned and drilled as shown to receive the rods, should be about 2 in. in diameter at the base and 2J4 in. long, so that they will fit the average axle.
SPIRALLY turned pedestals or legs are considered by 99 out of 100 home workers as being beyond the skill of any amateur mechanic without a lathe. Actually, however, they can be made with a few hand tools and some care. It is surprising indeed what can be made in the home workshop.
A Convenient Bench Is Essential in Any Home Workshop
TO BUILD an ideal home workshop bench is neither difficult nor expensive if the details of POPULAR SCIENCE MONTHLY’S Blueprint No. 15 (listed below) are followed. That print was used by E. Crass, of Paducah, Ky., in building the bench illustrated, and he writes as follows:
ANY one of the blueprints listed below can be obtained from POPULAR SCIENCE MONTHLY for 25 cents. The Editor will be glad to provide, upon request, information relative to tools, material, or equipment. Blueprint Service Dept. Popular Science Monthly 225 West 39th St., New York.
THE radio fan who takes pride in constructing as much of his apparatus as he can, will find it not at all difficult to make very efficient B batteries that not only have a long life, but also can be renewed again and again for a few cents when they run down.
ALTHOUGH not hard to make, the tobacco cabinet or humidor illustrated will grace any smoker's den or living-room. I have made three of these of quartered oak, for which I received $20 each, and one of walnut, which brought $30. 2 pieces, I by 10 by 20 in.
EVEN if you live in a congested city, with little or no gardening space, it is not necessary to forego all the pleasures of gardening. You can resort to barrel gardening, just as an ingenious resident of San Antonio, Texas, has done.
This Unique Rabbit Hutch Has Hay-Rack and Feed Trough
ALTHOUGH most boys at some time or other keep rabbits, few of them know how to build first-class hutches for their pets. It takes a little longer to build a good hutch like the one illustrated than to use an old box or barrel, but the result is worth while.
Some time ago Mr. Joe Rivers, a confirmed smoker of Edgeworth, defined the friend-making, friend-holding quality of Edgeworth as “tasty-smellfulness.” In the following letter Major Edmund simplifies this description into one word, “bouquet”—which Webster defines as “an aroma as of wine.”
1. Color is caused by differences in the length of light waves. Our eye sees the longer waves as red; the shorter, as orange, etc. The shortest waves of visible light are violet. White light consists of light of all the colors. 2. The explosion of dynamite is very different from burning; it is a kind of disintegration.