Crime-Detection Tests FOR THE Home Chemist
How Hidden Fingerprints May Be Found by Using Iodine Vapor â€” Forgeries Also Are Revealed by This Remarkable Element
By Raymond B. Wailes
NEW thrills await the home chemist who experiments with iodine. Besides its queer properties and varied uses, it serves as the gateway to a new branch of chemistryâ€”the mysterious and interesting art of scientific crime detection.
With iodine, the amateur experimenter can transform his home laboratory into a miniature crime bureau. In a few hours, he can master some of the chemical tricks that aid the modern sleuth in his search for hidden fingerprints, clever check alterations, and forgeries.
First, however, the amateur must learn how to obtain this active element in its free state. For years, it was recovered commercially from a giant type of seaweed called kelp. Now it is obtained from the solutions left behind when Chile saltpeter is crystallized in large quantities.
Magic in Chemistry, Chemistry in Magic
Prove you’re a man to be reckoned withâ€”and the only man who can make the gal in the photo (Fig. 1) blush. Prepare her for the test by painting her cheeks with phenolphthalein solution (from the drug store), and be sure the cheeks are slightly moist when you perform the trick. Ordinarily this solution is colorless, but when a finger (yours) moistened with household ammonia is brought near it, the reaction of the fumes with the solution causes it to turn pink. When the ammonia evaporates, the cheeks lose their color.
One of the things I really like about these old articles is that they assume a certain level of competence, and if you don’t have it, well that’s your fault. Nowadays if you posted this article you’d have to find out if you are libel for some moron drinking hydrochloric acid through the rubber tube because he thought it was a straw.
Generating SMOKE and STEAM for Amateur Theatricals
By Kenneth Malcolm
CURLING wisps of smoke rising in a fireplace, great smoke-gusts bursting in from an offstage forest fire, steam issuing from grotesque modernistic machinery or even from the spout of a humble teakettleâ€”all the realistic steam and smoke effects which so often add to the interest of professional dramatic productions can be easily duplicated, at least on a moderate scale, by the amateur.
The apparatus to be described is a simplified version of that used in the professional theater, and costs not more than a dollar or two. The smokeâ€”produced chemically by uniting ammonia gas with chlorineâ€”is harmless and may be generated instantly wherever desired.
Safe Stunts with Fire FOR THE HOME CHEMIST
By Raymond B. Wailes
OF ALL home chemistry experiments, tests with combustibles offer the most in spectacular fun and harmless excitement. For even after some 60,000 years of use, fire still holds a mysterious fascination.
Although we are accustomed to kindling a fire with a match or some other small flame, a spark or a flame are by no means necessary to start some substances burning. Many materials ignite spontaneously when subjected to nothing more than a slight rise in temperature. Carbon disul-phide, a liquid often used as an ant exterminator, is one of these substances and for this reason presents a serious fire hazard if not handled carefully.
STAMPS tell Story of Science
By Charles Irving Corwin
How a Collection Album Illustrates Many Fields of Human Knowledge
AN you describe in detail a common United States postage stamp? If you can, you are exceptional. We may think we know what they look like, but it is difficult to tell offhand, without peeking, just what figures or phrases are used, let alone describe the central picture or border designs. The recent Mother’s Day and NRA commemoratives are exceptions, since the criticism and controversy aroused by these miniature steel engravings made us examine them more closely. It is recalled that a vase of flowers was smuggled into the reproduction of Whistler’s Mother, and the fact that in the NRA issue business was out of step with labor and agriculture provoked some amusement, but even these two well-known stamps will catch most of us. For instance, is the “three cents” spelled out or indicated by a figure?
Better not let the TSA see this or they’ll ban corn from all flights.
Dynamite Made from Corn
Production of a highly explosive dynamite from corn is one of the latest developments of the chemical laboratory. It is the result of the recent discovery at the University of Iowa of an inexpensive method of extracting inositol, a sugarlike substance, from corn. Inositol is a non-explosive form of alcohol but when nitrated becomes a powerful solid explosive. It can be produced from the waste by-products of the manufacture of cornstarch.
HOW CHEMISTRY CREATES A PHOTOGRAPH
What goes on in the emulsion that coats film is shown by simple test-tube experiments.
By TRACY DIERS
THE film in your camera is thinly coated with one of the most unstable chemicals known to man. Silver bromide is its name, and from the moment of its birth it is kept in a cradle of darkness until in your camera a swift shaft of light seeks it out. The intricate and far-reaching changes brought to silver bromide by that flash of light are in part still secrets of nature. Much of what happens in your camera and in the darkroom is known, however, and can be shown at home with a few chemicals in a test tube.
Fate of UNIVERSE May Be Told in Cosmic Ray Origin
by JAY EARLE MILLER
Where in the universe does the mysterious cosmic ray originate? Science is now conducting extensive research to solve that mystery, for the answer may disclose the destiny of the earth we live on.
ON MOUNTAIN tops in Hawaii, Alaska, Peru and at other isolated points around the worldâ€”eighteen stations in allâ€”an answer is being sought this summer to the most perplexing question in modern science â€”what is a cosmic ray?
First discovered nearly thirty years ago, and made famous in 1925 when Dr. Millikan of California Tech confirmed their existence, and, much to his embarrassment, the press named them “Millikan’s rays,” the cosmic emanation continues to be the baffling enigma on which scientists throughout the world are divided.
This looks pretty fun though I’m not sure where you can buy uranium nitrate these days.
Fun with Black Light for Home Chemists
By RAYMOND B. WAILES
CHEMICALS that glow with magic colors in the dark, under invisible illumination with “black light,” have been applied to theatrical costumes and decorations with spectacular effect. Your own home laboratory can be the stage for equally striking experiments with these substances, which possess the curious property known as fluorescence. Also, you can prepare other substances that shine in the dark through the phenomenon called phosphorescenceâ€”which is distinguished from fluorescence by the fact that phosphorescent chemicals continue to glow for some time after removal from the light that excites them.
This is a really interesting early article about usability design. Specifically designing user interfaces that reduce error rates and speed up operations. I think people most commonly associate bad user interfaces with software but this article shows that it they have a long and distinguished history.
Be sure to check out the insane electric meters on the fourth page. It wasn’t enough to make the dials all go in alternating directions, no, they had to share numerals between them as well!
Psychology and the Instrument Panel
Designing indicators, switches and other controls to fit the abilities of the men who will use them is a joint problem for psychologists and engineers
by Alphonse Chapanis
OUR MACHINES have become so complicated that we have been forced in recent years to start a new branch of technology: namely, re-tailoring the machines to the abilities and limitations of human beings. This activity, called human engineering, is a new departure in the application of psychological principles to industry. Up to now the main emphasis has been on selecting and training the best man for the job. Human engineering tries to fit the job to the manâ€”any man.