934 



Popular Science Monthly 



Finding Leaks Quickly in 

 Air Tanks 



WHILE visiting a rock quarry I saw 

 the workmen using a new method 

 for finding leaks quickly in compressed air 

 tanks. A plug was removed in the upper 

 part of the tank and a large spoonful of oil 

 of peppermint poured in. The plug was 

 screwed back in and the compressor started. 

 The leak was soon found by the odor of the 

 peppermint. This method may be used to 

 advantage for finding leaks in small acety- 

 lene lighting plants. — Edward Gyger. 



Making a Bulb Planter 

 from a Foot Pump 



THE foot pump should have an mside 

 diameter of at least 1 3^ in. The plunger 

 is taken out and a hole bored through the 



base to ac- 

 commodate 

 the plunger 

 rod. The 

 handle then 

 being fast- 

 ened to the 

 end of the 

 rod, a piece 

 of i-in, pipe 

 is bolted on 



to the part 

 which nor- 

 mally is 

 held down 

 by the foot 

 but now serves as a 

 handle. The upper 

 end of the pump 

 where the cap was 

 removed is then 

 sharpened on the 

 edge of the tubing 

 so that it will enter 

 the ground easily. 

 In using this 

 planter the pipe is 

 held in both hands 

 and pushed into 

 the ground to the 



desired depth, which for bulbs is about 5 

 or 6 in. The wood handle then rises and 

 indicates the depth of the hole. On with- 

 drawing the pipe from the hole a solid 

 core of earth is left in the end of the pipe 

 which may be easily expelled. 



Inverted foot-pump used 

 as a bulb planter 



The advantage of this planter is that it 

 leaves a hole with a flat bottom and also 

 does not compress the earth as in the case 

 of a pointed stick. The maker of this has 

 put in several thousand tulip bulbs with it 

 in dry hard ground very satisfactorily. 



Substitute for an Automobile 

 Hub-Cap 



APIECE of inner tubing approximately 

 6 in. in length will serve as a ready 

 substitute for a 

 lost hub-cap 

 until a new one 

 can be provided. 

 Should such a 

 cap be lost there 

 is great danger 

 of the dust and 

 grit collecting on 

 the inside of the 

 hub and causing 

 damage beyond 

 repair to the 

 ball-bearings 

 within. The 



piece of tubing 

 is held to the 



Tube covering end of 

 hub to keep out dust 



hub with the aid 

 of wire wound tightly around it, while the 

 other end is closed with wire to prevent the 

 dust entering there. — Adolph Kline. 



A Drill of Self-Hardening Steel 

 for Working Marble 



DRILLING holes in marble is very 

 wearing on tools. A piece of the 

 best steel, tempered as hard as fire and 

 water will make it, loses its edge and its 

 size very quickly when used for this work. 

 It is not that the marble is so hard, but 

 the gritty nature of the material acts on 

 the tools like an abrasive. A parallel case 

 is that of machine-shop work on iron 

 castings which have not been well cleaned 

 of the molding sand. Machinists say that 

 the sand wears out tools faster than the 

 hardest iron. 



Concerns that make a specialty of marble 

 work, such as switchboard slabs, etc., use 

 drills made of self-hardening steel and find 

 nothing to equal it. A short piece of round 

 or square steel is flattened out to a drill 

 point and is generally used in a ratchet 

 drill following a hole made with a small 

 twist drill. Self-hardening steel can be 

 forged and allowed to cool in air without 

 affecting its temper. 



