Page:Popular Science Monthly Volume 88.djvu/322

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��Popular Science Monthly

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��A Home-Made Football Inflater

V A L V E from an old bicycle tire or an inner tube is a very serviceable substitute for the expensive and delicate pumps used to inflate footballs. Cut the metal ring and the rubbed pad from around the valve, and the inflater is ready for use.

Insert it into the neck of the foot- ball, attach the outer end of the valve to a bicycle pump, and your football may be quickly inflated.

A Dust-Proof Bottle for Acid

GLASS spirit lamp makes an excel- 1 e n t bottle for keeping small quantities of ni- tric acid, solder- i n g spirit or other acid liquids. A glass rod may be left in the lamp and covered with the ground cap as shown in the illustration. The cap usually makes a very good fit, and for many purposes no other stopper is re- quired.

When used to contain nitric acid, for testing gold, however, the other device shown may be adopted. A piece of glass rod is drawn out to a rather fine point at one end and passed through a per- forated India rubber cork, which forms an air-tight stopper.

A Multiple Punch

PUNCH for making a number of holes in sheet fibre or metal can be made from a block of steel machined as shown in the accompanying drawing. A punch of this type is intended for work that must be repeated with uni- form results.

����An Oil Tray Made Without Solder

OIL trays which require n o soldering may be made from a piece of tin of such thickness that it may be readily bent. The tin should be marked off as in

the illustration. Bend the sides up on the Hues AB and CD; then bend them back to their former place. Do the same with the ends on the lines XY and MN. Take the corner BY and bend along the line RT until the side and end come together and form a square corner, as in lower drawing. Bend the projection up against either the end or side. Do likewise to the remaining corners.

Parcel-Carrying Rack for Bicycle

THE accom- panying line drawings show a simple pack- age-carrying at- tachment for a bicycle, which can be cheaply and easily made and removed or at- tached simply. The drawings show clearly the method of bending and the dimensions. Make the pocket to suit the handle bar of the bicycle.

Switch Detects Bad Ignition

IT is often a te- d i o u s and troublesome mat- ter to determine which cylinder of a multiplex cylin- der engine is missing explo- sions. A very sim- ple little instru- ment, shown in the accompanying sketch, renders the discovery of the missing cylinder easy. It is simply a switch, to be fastened to the spark plugs in succession.

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