Page:Popular Science Monthly Volume 91.djvu/921

 Popular Science Monthly

��905

��A Cattle-Guard Made of Cactus. Horses and Cows Avoid It

AN ingenius foreman on an Arizona rail- l\ road recently conceived the idea of using the cactus plant as a cattle-guard at railroad crossings. The first, which was planted a few months ago, has proved an un- qualified success. Not a single ani- mal has at- tempted to cross it. As a matter of fact, both horses and cattle are thoroughly familiar with the species of cactus used, and fight shy of it as they would of a rattlesnake. A frame of two inch by six inch timbers was placed between the tracks.

���The cactus hedge for railroad crossings. The frames at the side furnish a footing for workmen

��on edge and fitted In the bottom of this structure are a few inches of sand and gravel in which the cactus plants were placed. The cactus is very long lived, but as it grows in abundance along the railroad, it can be renewed if overlap small-* ^Expandedposmon necessary. As the when gb^"T"^»x c: ™ :: jg thorns will pierce an. ^"^v^-^t^ contracted^ ordinary boot or A-^V shoe, it was necessary to place a piece of timber along the bot- tom bar of the fence to allow employees to cross.

This is by far the cheapest form of cattle guard in use on any railroad.

��A Collapsible Concrete Form Which Works Like an Umbrella

ANEW type of adjustable and col- lapsible steel concrete form works on the principle used in constructing the ribs of an umbrella. The form is made in two types, one for circular cul- verts and the other for small bridges with semi -elliptical arches. Both

types are collap- sible for greater ease in shipment from point to point or for move- ment ahead, as each section of culvert or bridge is concreted and hardened in place. Each type is also

��adjustable, the culvert type from twenty to forty inches in diameter and the bridge design from spans of six feet to forty feet. The fact that both units are adjustable with- in such comparatively wide limits greatly reduces the cost of the forms used because of their reduction in

����Threaded T bar

��Diagram showing the principle on which the diameter of the form is increased or decreased

��number. With the ordinary wood types a special form would have to be made for each diameter culvert or each differently spanned bridge. Be- cause both types are of steel instead of

��wood, they last indefinitely and reduce the cost of form construction.

��!B» ' ilsi

��Turning the hand-wheel adjusts the angle of inclination of the radial arms

��The adjustable bridge form. The over- lapping surface plates are forced in or out

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