Mechanic Arts High School - Artisan Yearbook (Boston, MA)

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TH E ARTTSAN 29 STILL l'ICTl'llES OF HIGH-SI'l'IEIl ENGINES NOXV TAKEN To study the behavior of machines while they are running at high speed by Hstopping' or slowing down the rapid motion so the eye can perceive it. an improved type of instrument known as a stoboscope has recently been developed. VVith this type of apparatus it is possible to take still or moving pictures show- ing the speeding parts of machinery in clear detail. Such pic- tures are made possible by using a thyratron tube of the mercury- arc type, the intense actinic light of which allows making photo- graphs at exposures of ten-millionths of a seco11d. NINE-FOOT LIGHT TESTER One of the instruments used at the General Electric Com- llIlllj',S laboratories at Schenectady. N. Y.. to measure the output of various lights is a double-leaf diaphragm, similar to the one 011 an ordinary camera, the iris shutter. It is employed to cover a photometer which is said to be capable of gauging the intensity of almost any size of a lamp, from the tail-light of an automobile to a searchlight of o11e billion candlepower. THE AUTOMATIC CHEMIST Now comes the Wautomatic chemist, a device that relieves the chemist of one ot' the most tedious parts of making an analy- sis. As recently demonstrated in New York City, the automatom measures either the acidity or alkalinity of a solution or the amount of certain ingredients in it. When the measurement is completed a bell rings and lights a light. This fundamental operation known to chemists as Ntitrationv is important in every application of cl1e.mistry, from making shoe leather to the testing of a city's water supply. A careful titration may take half an hour of a cl1e1nist's time, but theauto- matic chemist requires no attention after the start. A beam of light from a lantern shines through the beaker containing the solution, falling upon a sensitive electric cell opposite. When the. solution turns white or neutral at the addition of one drop of the acid or alkali, the electric eye turns off the supply and rings the bell. The amount' of acid or alkali required to neutra- lize the solution can then be read from the graduated tube. The automatic cl1e111ist has bee11 found to be very accurate.

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28 THE ARTISAN A giant and a midget among electric lamps appeared to- gether recently in one of the laboratories of the General Electric Company. A tiny neon light, a quarter of an inch in diameter, claims the distinction of being the smallest lamp ever made to operate on the ordinary 110-volt household lighting system. Its big brother, one of the world's largest incandescent lamps, de- veloping approximately 100,000 candlepower, is used for motion picture studio lighting. SICAPLANE LIFTS FIFTY-FIVE TONS On its much-delayed way towards South America from Ger- many, the giant German seaplane, D0-X, recently set a new world's record for heavier-than-air machines. In a test flight it lifted a total load of 55 tons into the air. HEAT-RESISTING GLASS Glass designed to resist the extreme temperature oil a giant rotating aerial beacon has been perfected. The dome- haped cover of the light is so large that a person can stand head and shoulders inside of it. ln shape this cover resembles the old bell jars of the nineties. The moving parts of the air beacons will be kept clear from much dirt and grit by this glass dome- shaped cover. U i..i.... MOLTEN SPRAY KEEPS RAIL JOINTS TIGHT Faced with the heavy expense of tearing up pavements to tighten loose rail joints, electric railways are interested in a process which keeps the rail points tightened over an indefinite period. The theory that the rail joints were loosened by rust and mill scale at the rail ends and not by vibration, was responsible for the discovery of this process. This permanent tightening process involves the spraying of molten metal at the connections, compressed air being used to blow a fine mist of metal over the entire area to be assembled. Copper, brass, steel, chromium, nickel or any other metal may be used for the plating. SIGNx1'ROJl+1CTlCll ONTO BUILDING BY SEARCHLIGHT Transforniing the woi-ld's tallest skyscraper into an illumi- nated bill-board, a powerful S9ill't'llllgllt was employed recently to project words onto the side of the Empire State Building in New York. The light cast the words, The United States Army Builds Mend o11to the wall.

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If , r' ,f , 5' I IV , f , ,C , ' ' 1 1 f,,cw . - 30 Q THE ARTISAN 25,000 SLICES TO AN INCH The most modern machines for making thin slices can pare them off measuring' one micron thick-or 4-l00,000ths of an inch. These machines, known as microtomes, are used in biological laboratories for cutting fragments of specimens for microscopic examination. Some ot' these. are automatic devices which will prepare from one specimen a series of sections for comparison. WURLIVS HIGHEST SUSPENSION BRIDGE High above the waters of the Arkansas River, across the Royal Gorge, that in places attains a depth of 2,600 feet, cables are being slung for a suspension bridge. This bridge, it is said, will be the highest in the world when completed, Ellld is situated near Canon City, Colo. Huge openwork steel towers sunk into solid concrete masonry on either side of the gorge support the work. The main span of the. bridge will be S80 feet long, while the entire bridge including tl1e approaches will have a total length of 1,200 feet. MOTORS' PLACED IN GREATEST AIRSHIP High amid what appears to be a mass of tangled stee.l girders, mechanics are now installing motors that will drive the Akron, huge Navy airship and largest in the world, now nearing completion at the tloodyear-Zeppeli11 dock at Akron, 0. They will break all precedent in airship construction by being placed inside the hull. Earlier airships had their motors on the outside because the ships were lifted by hydrogen gas. An exhaust fiame or electric spark might ignite the highly intiammable. gas. When non- intlammable helium intiates dirigibles, no such precautions are necessary. The engines will drive propellers that can be pointed in any direction to propel the ship up, down, forward or back- ward. p l-..--E. GIANT ELECTRIC LIGHTS FOR NORTH POLE SUB When the. Nautilus, Sir Hubert Wilkins' submarine, plunges under the Arctic ice cap on its voyage to the Pole this summer, it will not be entirely blind. Two huge electric headlights of 1,000,000 candlepower each will cast beams of light nearly 100 feet ahead of the vessel. The lamps were tested to a pressure of 100 pounds to the square inch.