Page:Popular Mechanics 1928 01.pdf/121

 

Housekeepers are sometimes puzzled at the tendency of hot-water pipes to freeze more easily than those that carry cold. The apparent mystery is explained by Leon McCulloch, research engineer of the Westinghouse laboratories. By means of a special testing apparatus he found that the freezing is due to a wall of water established by dropping temperature. Water is densest at thirty-nine degrees Fahrenheit. In a closed pipe, when the temperature falls toward thirty-nine degrees, that part which is being cooled becomes denser and then lighter below the thirty-nine-degree mark. Water that has not been cooled above the section exposed to the cold remains lighter, so that between the two areas of lesser density is a "wall" of dense water around the thirty-nine-degree region. This wall naturally limits the circulation, so that the exposed area is more likely to freeze. In the cold pipe, circulation permits the contents to remain more nearly at thirty-nine degrees, and the restricting wall is not present.

 

Attached to the windshield with rubber vacuum cups, an auto map rolls up like a shade when not in use, and is always in handy position. It occupies but little room, does not obscure the view when shut and is protected from dust and the weather in its holder.



 



Fashioned on the lines of a monoplane, a new type of kite has been introduced by Perry T. W. Hale, all-American football star of 1900, who was blinded in an explosion some twelve years ago. It requires no tail and is said to be extremely popular with kite enthusiasts.

 

Passengers on the electric ship "California" may take their automobiles with them at a minimum of trouble and risk, for the vessel has a garage with a capacity of 140 cars. The autos are loaded without hoisting, through side ports, and may be checked like baggage. The "California" uses electricity for almost everything except broiling steaks in the kitchen. Charcoal is employed for this, but the ship's propellers, clocks, elevators, steering apparatus and many other units are run with current generated by huge turbo-generators. The vessel is 601 feet long and has a beam of eighty feet. When it passes from a cold into a warm climate, the electric current is switched from the stoves to fans that drive cooled air over brine pipes. It is the largest commercial liner built under the American flag.

