High-Tech for 1931

This list of innovations was taken verbatim from the December 1931 issue of The Reader's Digest. No author is given, and the article is entitled "The Age of Ingenuity." 

• You may have a new book read to you, while you rest your eyes and take it easy. A reading machine to be put on the market by Radio Corp. of America uses a strip of talking picture film on which the reading of a complete novel can be recorded on 30 feet, an opera on 15 feet, or a symphony concert on 3 feet. You turn the knob and listen to a chapter or two out of the best book of the month, or some of the classics, if you prefer. Next evening, at the same receptive period, the reading may be resumed where you left off, and you can take it as slowly or as rapidly as you like.
• Travelers in Pullman cars are now being offered "radio pillows," containing miniature broadcast receivers that enable them to tune in without disturbing their fellow passengers.
• Coin-in-the-slot typewriters for public use in hotels and postal and telegraph offices have been designed by a German firm. Putting money in the slot, a depositor may make 1000 strokes with the machine. Attached to it is a device counting strokes as they are made, showing the user when he is approaching the end of his number. When 1000 have been made the machine automatically locks until another coin is deposited.
• Now comes the electric carillon, a device developed in the workshop of the RCA Victor Company. It consists of a series of small steel chimes like those of a household clock. These are struck by tiny hammers actuated by a piano keyboard. The tones are scarcely audible, but the vibrations create feeble electric currents which are then amplified millions of times by a vacuum tube. Played from a church tower through giant loud speakers, their sound is more powerful than that of the largest bells in the world. Runs or trills can be played even more rapidly than on a piano, something not possible with the old-style chimes, and the notes can be varied to any desired intensity.
• A company in Louisville got the idea of carrying the manufacture of baking powder biscuits up to the point where they are cut out of the dough; leaving the baking only to be done, as needed, in the home. It sounds fantastic, doesn't it? Yet the idea has succeeded so well that branch factories are being established in several cities. You buy the biscuits (two or three kinds) in vacuum tins, open the can, peel them off, bake them- and have fresh, hot biscuits with no work and almost in no time.
• The tomato-juice cocktail, popular as a before-dinner or between-meals beverage, is to have a rival in cocktails made from cranberries. American Cranberry Exchange, cooperative organization of cranberry growers, has launched the new beverage, and expects it substantially to increase consumption. Important advantages are claimed for the new cocktail: an appetizing color that everyone associates with refreshing beverages, clear and sparkling appearance, easy blending.
• "Seaweed Bread" has just made its appearance on the Pacific Coast. Made from the giant kelp plants that grow 50 feet long in beds along the California coast, and recently introduced for the first time upon a commercial scale, it contains iodine and a number of other minerals  declared to be useful in correcting diet deficiencies. Its odd flavor is said to not be disagreeable. Previously seaweed has been used for feeding cattle.
• The Biological Survey of the Department of Agriculture at Washington has developed a rat poison which is not poison to anything but rats. So far as I know, it is the only case on record of a poison being specific for just one thing. The stuff would kill other things but for two reasons: In the first place, nothing else but a rat will eat it, save in minute quantities. In the second place, when eaten by anything but a rat the poison acts as an emetic. It acts so quickly and so vigorously as an emetic that not enough of it is ever absorbed to do any damage. A rat, however, has no facilities for getting rid of anything he has once eaten, It is one of the few animals unable to vomit. This rat remedy is known as Red Squill.
• Thousands of dollars may be saved annually for pear growers of Oregon and Washington by the use of copperized paper, a discovery of the U.S. Department of Agriculture. Used to wrap pears in storage while they are awaiting shipment to the consumer, it prevents the spread of "gray mold," a troublesome and costly type of decay. Ordinary paper wrappers are impregnated with a liquid copper solution developed for the purpose by the plant pathology bureau of the Department of Agriculture.
• Even goldfish skins can now be used to cover evening shoes for women. The result is a glittering pair of slippers of unusual brilliance. A tanning process developed by a German scientist, George Ahrenreich, preserves the tender skins of the New Zealand species of goldfish which are used.
• "Mudguards" of thin light rubber which pull on over stockings may now be had to protect silk hosiery on rainy days.
• A new occupation open to women and girls is that of "air maid" or social hostess on passenger planes. Most of the big air transport lines of the United States now have an "air maid" on each plane. England and Japan also are installing them. Women who know how to get along with all kinds of people are preferred. They make themselves agreeable  to passengers, see that they receive refreshments at proper times, answer questions, make a hand at playing bridge or other games.
• "Women who have pale grey or blue eyes can have them darkened to any desired degree by contact glasses," Prof. Leopold Heine of the University of Kiel has reported to the Lancet, British Medical Journal. Contact glasses are thin shells of optical glass which can be worn under the eyelids in contact with the eyeball. They cannot be distinguished, which gives them a cosmetic value very pleasing to women and to actors.
• Unbreakable spectacle lenses are a recent innovation. Two pieces of glass with a piece of celluloid between them are cemented together under pressure, forming one solid piece. This "glass sandwich" is slightly thicker than ordinary glass but it is just as transparent, the celluloid being invisible. Unbreakable glass has for some time been used in auto windshields and airplane and factory goggles, but this is believed to be its first use in  spectacles.
• You roll your own with a new cigarette-making machine, sold with tobacco, papers, and metal cigarette container for $1.
• Westinghouse have announced a nofuse load center which replaces present-day fuses and their attendant bother and danger. The invention is simply a switch, similar to those used at present. When too much electric current is going over the wire for safety the switch merely shuts off, instead of a fuse blowing out. When the extra load has been removed from the circuit, an iron, heater, cooking appliance, or whatever it may have been, then the switch automatically closes and the current is again turned on. There will be no more burnt fingers or cobweb covered heads with this switch in use.
• Traffic policemen in Paris are to have their hats illuminated with phosphorescent paint so that they may be seen by motorists on a dark night.
• A liquified lead coating for metal has been developed in England. Having a positive amalgamation with iron or steel, one coat is said to make metal permanently rustproof.
• A new way of heating rooms is being tested in the Westinghouse laboratories. Details as yet are few. A special finish is given to the walls of the experimental room. Heat comes from walls and ceiling. The entire surface may be warmed or the heat merely switched on section by section where it will do the most good. These sections radiate a mild temperature about equal to that of the human body.
• Waitresses in the Stevens Hotel, Chicago, no longer kick open the kitchen doors; in passing an electric eye, their shadows interrupt the beam, actuating a mechanism which opens the door. The Studio Theatre, in Hollywood, California, employs the same device to open doors for patrons, turn on drinking fountains, and so on.