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��Gliding Boat for Tropical River Mail Service

��A GLIDING boat that speeds over the water at the rate of fifty miles an hour has been built for transporting mails on the Magdalena river in Colum- bia, between the Carribean coast and the capital city, Bogota, a distance of six hundred miles. On her trial trip, from the factories at Nyack, N. Y., to the foot of Ninety-first Street, New York, a dis- tance of twenty-two miles, the "Yolanda 11" covered the distance in less than a half hour.

��Popular Science Monthly

The Steam Engine in War

THAT the Lanz locomobile, the name by which a remarkable port- able superheated steam engine is known, is equally as successful for war as well as peace purposes is convincingly shown by its behavior during the past year on the various battle fronts.

One of the most interesting applica- tions of the locomobile is for power pur- jx)ses in connection with field equipment, such as wireless telegraph sets. One lo- comobile is supplying energy to a two hundred horsepower field wireless equip-

���This gliding boat, which takes its power from the displacement of air instead of water

by its propellers, was built in New York for use on a tropical river, where weeds make the

use of screw propellers in the water impossible

��Two gasoline engines of one hundred and fifty horsepower each are connected to an air propeller. It is impossible to use screw propellers in the Magdalena, as the sea weeds and grass are so thick.

The Yolanda II draws three inches of water while speeding at a rate of fifty miles an hour, and five inches while at rest. She was designed by Gonzalo Mejia, an engineer of Columbia. The prob- lem of transportation on tropical rivers, where the shallow draft of encumbering sea weed, makes a draft of more than a few inches impracticable, has engaged the attention of native engineers for years. Mr. Mejia's boat is one of the best devices yet built to meet the prob- lem.

��ment. The locomobile is used extensive- ly in operating pumps directly behind the firing line. A more extensive use is in supplementing the power plants of ammunition factories.

In one plant two locomobile units of five hundred horsepower each were add- ed ; in another, which, before the com- mandeering of the fuel oil supply, had been employing oil engines, a single one hundred and twenty horsepower locomo- bile engine supplanted the entire power equipment.

Among other applications of the loco- mobile are hauling gims and ammunition trains to the various batteries, and in heating hosj^itals and prison camps with ihe hot water from its boilers.

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