Page:Popular Science Monthly Volume 91.djvu/182

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��Popular Science Monthly

���A small Niagara which has been de- veloped indoors as a part of the hy- draulic laboratory

��It takes a power plant of 500 horse- power (see photo- graph at the right) to make the mini- ature Niagara

��also commercial forms and sizes of turbines under large energies of water may be studied. The whole ap- paratus is fitted with meas- uring devices so that precise measurements may be made at any point. One engineer who inspected the outfit said, "This is using a river and measuring its effects with a teaspoon," so delicate are the tests applied.

In the basement of the school there are eight hun- dred feet of canals supplied from the Charles River Basin. These have turns and narrowings and junc- tions, so that the flow may be observed under all possible conditions. The outfit includes many pumps and engines for the work, aggregating about 500 horsepower, together with compression tanks and all the essentials for a mammoth indoor hy- draulic laboratory.

��The Largest Indoor Waterfall in the World

THIS waterfall is not out of doors, nor is it used for the development of power, but it represents the flowing of one hundred tons of water each minute and en- ergy of more than three hundred horse- power. It is part of the laboratory equipment at the Massachusetts Institute of Tech- nology, and illustrates how this

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��school teaches by means of commercial quantities under ordinary condi- tions.

The water here shown has been lifted to an elevated canal, which the students call "the big brook," forty feet above the base of the pump, and returns through a great pen- stock ten feet in diame- ter to the outflow canal. The conduct of water under such pressure and

��VCORD.

���Instead of tying the ends of the cord you simply fasten them in the wire loops. The wire takes the place of the usual knot

��It Fastens Cord Tighter Than You Can Tie It

PACKAGE tie designed to fasten cord without tying the ends, has been invented by Warren L. Bald, of New York city. The inventor claims that his tie will fasten a cord tighter than any knot ever devised and will hold the cord more securely than a number of knots.

A spring wire takes the place of the usual knot. Only two operations are necessary to tie the cord. The cord is hooked around the wire loops, and, when a strain is put on these loops, the cord is pulled tighter, the spreading of the wire acting as a lever. The device not only saves the fingers of the person who wraps a large number of packages daily, but with the cord properly se- cured in the wire loops it is impossible for the packages to fall apart.

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