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Page:Popular Science Monthly Volume 89.djvu/108

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94

��Popular Science Monthly

���Trenches are now excavated and filled by machines. The filling-machine operates the scraper at a rate of speed wholly beyond that attainable by a man and a team

��Filling Trenches by Machine AN advance step has been taken ±\ in the construction of sewers and the laying of water-mains. With the modern trench-filler no time is lost in refilling the excavation. The contents of the deepest and longest earth opening can be put back in double-quick time.

The new machine is a gasoline-engine which drives a windlass by means of which a steel cable is wound. To the end of the cable is attached a steel scraper. The engine and equipment are mounted on a movable truck. Such is the construction that the machine can be used either on the truck or can be removed entirely by simply taking several bolts out of the turntable.

The new apparatus readily adapts itself to several other uses in connection with trench operations. It is used to pull heavy cables through conduits, to raise and lower giant telei)hone poles into their rcsi)e(ti\e places, as well as to load and iniload pi|ie and place it in trenches.

The engine is of four and a half horse- power. It operates the scraper at the rate of one liundred and fifty feet per minute in ordinary soil and one hundri'd feet per minute in heavy clay. The speed is regulated to suit the .soil by a change of sprockets on the engine's crankshaft.

The crew for oix-ration consists of two men — one to pull the lever control-

��ling the windlass and the other to handle the scraper. The instant the scraper reaches the edge of the trench the power is released, and the helper draws the empty scraper back to position ready for another load.

��The Amazing Beetle

ONE of the most amazing things in natural history is the way in which beetles have triumphed in the struggle for existence. Of all creatures they are by far the most numerous, no fewer than 150,000 distinct species having been identified — three times the number of backboned animals.

Beetles are wonderfully adaptable. They are found practically ever\-where — in the frost-bound tracts of Iceland and in the hot desert sands of Africa; on the highest mountains, under the ground, and as fossil, in the deepest strata; on land and in water: on plants, among stones, and in wood antl earth; and even in the very craters of volcanos.

But there is one place where no beetle has yet been found — it is the inhosjiitable land of Spitzbergen, to the north of Russia. Here are mam- mals, birds, fish, molhisks, crustaceans, a few insects of varied s|X'cies, and man>- spiders, but not a single beetle. While other insects have succeeiled in some way in migrating from the main- land, the beetles have apparently been unable to cross the wide, icy waters.

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