Page:Popular Science Monthly Volume 88.djvu/953

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��Gaging the Stack Draft ^HE draft pressure of a stack is expressed in inches of water, mean- ing the amount of draft required to change the difference of equilibrium of two communicating columns of water, measured in inches.

The draft of the chimney can be easily obtained with the use of the little gage illustrated herewith. The fuel consumption of a boiler can be figured whether or not it is in proportion to the results, etc. The illustration shows how such a gage is made. A single length of glass tubing with an inside diameter of yi in. is bent to the required shape by holding over a small flame and bending very slowly when hot. Fasten to a board with wire or brass straps. Arrange a scale of inches between the two columns. To read the draft, place the gage on a wall in a vertical position and put a little water into the tube so that it just balances in either column. Connect a piece of rubber tubing to the left leg and seal in a small opening in the stack or pipe. The draft or suction at the end of the tube will cause a slight vacuum in the tube and will cause the two columns of water to change their level. The draft may vary from % in. to 2 ins. according to height of stack, temperature and weather conditions. The draft pressure rccjuired will depend upon the kind of fuel used. Wood needs little draft, about J/2 in. or e\'cn less. Bitu- minous coal will require ;^<+ in. to i in. and anthracite or slack will need a draft of iK ins. — B. F. Dashiell.

A Safe Way of Bending Pipes ''T^HOSf^ who try to bend piping with- JL out kinking by filling the pipe with sand and still fail, will attain better suc- cess if they pour molten lead into the pipe, allow to cool and then bend. Heat the pipe, allowing lead to ilow out.

��Popular Science Monthly 925

A Toy Rubber-Elastic Winder

A DISCARDED egg-beater may be easily converted into a toy aero- plane winder. Cut off the loops which formed the beater part. Wire the stubs together and make two wire hooks or loops for fastening the rubber bands. The winding will be greatly facilitated by increasing the length of the crank.

���Glass tube used for gaging stack draft

���An old egg-beater can be converted into a good toy winder for rubber motors

A Cheap Beam- Compass

A WOODEN rod, such as drygoods merchants use for cloth, makes a good beam-compass, by attaching a pencil and nail as shown in diagram. The pencil is flattened on opposite sides, to be gripped in the beam, and the head of the nail has been filed off. The rings consist of brass tubing. When using ink, the ruling-pen is gripped like the pencil. — Wm. Turnpenny.

drass Ring § ' ^'D/a*^n/cM^

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��Diagram showing construction details of beam-compass

Removing Waterproof India Ink Spots

IT is not generally known that black India ink, especially the waterproof kind, may be rcmo\ed from nearly any material by placing a blotter underneath and pouring household ammonia over the dried ink. Care should be taken that the blotter does not become satu- rated with the blackened ammonia.

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