Science: Technology Notes

Recent news of invention and engineering:

> On the Anacostia River near Washington’s Navy Yard, engineers tested fluorescent buoys to be used as markers for alighting seaplanes. Having no hot filaments to burn out, fluorescent lamps (coated inside with powders which shine by electrical agitation) are durable as well as efficient. The buoy lamps are carried on inflated floats shaped like doughnuts, which contain short-wave radio receivers so that the lamps can be turned on & off by remote control from shore.

>Breaking up coal in veins by use of explosives is still standard practice in U. S. mining, and despite precautions is still hazardous. Coal Age described a new method of mining by hydraulic pressure: a hole is bored in a coal seam, a rubber tube is inserted in the bore, and the tube is then powerfully expanded by forcing oil into it, fracturing the coal. Experimental installations broke about 2.500 tons of coal each before failing.

> For fast, non-smudge printing, various means have been devised to make ink dry almost instantly when it hits the paper—absorption, evaporation, oxidation, polymerization (molecular clustering). In the “flash-dry” process, the newly printed paper passes between jets of flame and the liquid part of the ink ignites with a flash, leaving a dry residue. The June Technology Review (M. I. T.) describes a new “frozen” ink for porous papers like newsprint. The ink is solid at room temperature. It is fed like lumps of coal into the press, which heats it to fluidity, at 200° F. On reaching the paper it rapidly cools and solidifies.

>Women’s stockings made of Du Pont’s synthetic nylon recently went on general sale in the U. S. (TIME, May 27). Meanwhile, the company has kept on making nylon more versatile, finding new tricks to do with it. Du Pont has been assigned patents on: 1) a “sulfone” nylon which is especially resistant to acids and alkalies; 2) a nylon resembling wool, made by mechanically crimping the fibres; 3) a method of pre-shrinking nylon fibres.