Page:Popular Science Monthly Volume 91.djvu/486

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��Popular Science Monthly

��% A by % in. in size, nailed thereto. The two lower depending strips, arranged in V-shape, are secured together at their lower ends by a cross-strip which rests on the keel strips, in the manner described in

��rusted from water working in around the beads when the tires are run soft, or through neglected cuts in the tires, or from neglect to put proper fittings on the valve stem, the rust should be removed with

���reference to the end frames. Pins or Screws may be used to hold the seat frames to the body of the canoe, but small bolts are preferable for this purpose.

The entire framework, together with the Canvas and oars, can be knocked down and folded in a space 6 ft. long, I ft. wide and 6 in. thick, and can easily be shouldered and carried by a boy. The end extension pieces B, swing down and rest between the keel strips A. The hinges on the side bars D, provide a means for swinging the end pieces alongside the bars for packing purposes.

��The Cause and Prevention of Rim Cuts on Tires

PROTECTION from rim cutting is not afforded by any particular type of tire but depends rather upon the design, quality and usage. No good tire of standard type will be cut by any standard rim, if properly used. On the other hand, any type of tire will be injured if subjected to abuse. Under-inflation, dented and irregular rims, excessive loads, tire fillers and stiff reliners are the common causes for cutting and breaking above beads. The flanges of a rim may be battered down and roughened as a result of a tire being used deflated for a considerable distance. When another tire is applied it is sure to cut above the beads. Tires carrying heavier loads than those for which they are designed may break at the beads where they are engaged by the clinchers of the rim. If rims become

��Detail of the parts for making the frame in the construction of the canvas canoe

emery paper and the rims painted with a coat of aluminum, graphite and oil.

It is not uncommon for tires to be applied to rims of wrong size through a mistake as to dimensions. Sometimes a 36 by 43^-in. tire is placed on a 36 by 4-in. rim. The diameter of this rim is ap- proximately 28 in. and the diameter of the beads of the tire approximately 27 in. for a quick detachable type, and approximately 26 in. for the regular clincher type, there- fore it becomes necessary to stretch and strain the beads considerably. Again, the 43^-in. beads are not constructed to fit a 4-in. rim, and will not engage properly in the clinchers. Good results cannot be secured when the beads are strained and crowded in this manner.

��Trick of Passing Cigarette Smoke Under Handkerchief

PLACE an ordinary china saucer over an empty glass tumbler and cover the whole affair with a handkerchief. Place the bundle on a table. Light a cigarette and blow a few rings of smoke towards the hidden tumbler. Then make a few magical passes. Remove the handkerchief and saucer and the smoke will be found in the glass.

To effect this you rub a few drops of hydrochloric acid on the inside of the glass and some ammonia on the saucer. The two fumes combined produce a vapor resembling cigarette smoke.

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