Page:Popular Science Monthly Volume 92.djvu/70

 54

��Popular Science Monthly

���Hoisting the concrete boat which weighs more than a ton. It is giving as good service as a wooden boat

��presented it to the U, S. Naval Reserve Force Auxiliary, at Chicago, which is a part of the Great Lakes Naval Training Station. The boat has aroused great interest, principally be- cause it is the work of a man with practically no knowledge of shipbuilding and with very little knowledge of concrete.

The boat is eighteen feet, six inches long, with a beam of four feet, six inches. It is propelled by a six-horsepower engine and despite the fact that the hull was not smoothed off it is cap- able of making a speed of ten miles an hour. Concrete, con- sisting of one part Portland cement to one and a half parts of sand, was applied with a trowel on a carefully designed framework of steel ribs, and was allowed to harden under cover. The boat weighs two thousand, three hundred pounds, twice as much as a wooden boat.

��The Great Lakes Training Station Gets Its First Concrete Boat

FOR many years concrete has been successfully used for barges and pontoons, but it is only recently that it has been used for other types of vessels. Norway has completed a concrete boat of three thousand tons, and a much larger boat is now being constructed in San Francisco. Montreal and Seattle are centers of concrete ship- building and New England ship- builders are watching the ex- periment with in- terest.

The accom- panying illustr;-.- tion shows a con- crete boat built by Walter N. Dow- sey, a lumberjack of Iron River, Michigan. He

��The axle periscope inspector to examine comotivc axle and to

��Looking Through a Steel Axle with a Periscope

THE periscope, so efficient in trench and submarine warfare, now has a pacific application. It promises to avert many accidents resulting from defective locomotive axles.

The axle is bored longitudinally, the size of the bore being ample to per- mit insertion of the periscope, which is about forty inches long and one and one-half inches in diameter. At one end is a magnifying mirror upon which a light is thrown from the handle. Looking through the periscope, in- spectors obtai/i a clear view of every part of the axle

^,, ., . and are enabled to

enables the railroad ^ • ^ j.\ a

every part of the lo- detect the flaWS m

locate flaws instantly the steel.

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