Page:Popular Science Monthly Volume 88.djvu/952

 924

��Popular Science Monthly

��wide by lO ins.

���the vertical rib of 540 pounds, which is nearly the ultimate. It will not be necessary to demonstrate further than the figures given, that this kind of kite flying is strenuous enough to hold a man's attention when his whole battery is aloft in a lo-pound wind.

The reel is made of two- circles of J^-in. material, 6 ins. in diameter. To one side of these pieces, other circles of ^-in. material, 12 ins. in diameter, are glued cross-grain, and further secured by a half-dozen clenched brads. To the inner 6-in. circles nail slats of ^-in. material, i in. long. Cut the holes in the center of the ends I in. square; put a square stick tightly through these holes, allow- ing it to project 2}^ ins. at one end and 3 ins. at the other. Turn bear- ings for the frame in each of the pro- jecting ends. These will be I in. in diameter. If you have no lathe you can whittle them

with a knife and sandpaper. The frame is made, as shown in Fig. 13.

Obtain two grooved pulleys of the diameter shown and a piece of sewing machine belt. Put the belt on the pulleys crossed. This will give it better contact. Screw into the 12-in. pulley a handle about i3^ ins. from the edge, and you have a good stout reel which will bring your string in four times as fast as an ordinary reel. You will appreciate this when you have tried both. No checking arrangement is needed on your reel. When necessary to check, take the string in your hand and snub around the projecting end of the axle. Two iron pins, 15 ins. long, of ^i-in. round iron, pushed slantwise toward the front through the i-in. holes into the ground, will take the strain.

The construction and methods of flying the Blue Hill box-kite and the tetrahedral cell will be discussed in the next issue of the Popular Science Monthly.

��FIGURE 14

��How to Protect the Surface of a Laboratory Table

STRONG acids and other chemicals of strong composition are continu- ally spoiling the appearance of laboratory tables. The following treatment may therefore be found of service. It can be recommended for preserving the ex- perimenting table from the injurious effects of strong acids or alkalis that may be accidently spilled, provided the liquids spilled are not left on too long. Two solutions are required, as follows: The first one consists of one part of bluestone dissolved with one part of chlorate of potash, in eight parts of boiling water.

For the second solution, dissolve 1 3^ parts aniline h\'dro-chloride (which a chemist can obtain to or- der), in 10 parts of water. Having thoroughly cleaned the table, apply the first solution as hot as possible, and with a flat brush. Apply another coat as soon as the first is dry, and then two coats of the second solution. When thoroughly dry, rub with raw linseed oil, till polished, and wash with hot, soapy water. A good black surface is thus given to the wood, in addition to the acid-resisting cjualities. After it is per- fectly dry, a little linseed oil, applied with a cloth, will also be of advantage. A hard surface with considerable luster is thus obtained, which will resist damage to its surface, especially from acids. — Wm. Warnecke, Jr.

A Mission Stain

ONE of the best and cheapest stains for mission furniture can easily be made by mixing black asphaltum with turpentine. Any desired brown shade can be obtained by varying the amount of turpentine. Apply the mixture to the work with a brush. After it has been on a minute, rub it dry with a clean cloth or cotton waste. It will dry quickly and leave a dull mission finish.

�� �