Popular Science Monthly 



187 



turned until this reading showed through 

 the slots. Then by turning the knob shown 

 on thecasing, this odometer would be thrown 

 out of engage- 

 ment and the 

 odometer for the 

 new tire, No. 5, 

 engaged. If this 

 tire ran* 1 ,000 

 miles before re- 

 m o v a 1 , the 

 odometer for 

 tires 2, 3, and 4 

 would each reg- 

 ister 2,000 miles 

 at that time. As 

 tire No. 6 was 

 put on in place 

 of No. 5, these 

 mileages would 

 be automatically 

 added to until the tires were taken off, ..at 

 which time the respective odometers would 

 register accurately the mileage covered. 

 The miles per gallon of gasoline or miles 

 per quart of lubricating oil are obtained by 

 pencil and paper calculation. 



The walls of the circular garage are eight feet 

 eight inches high and are reinforced with wire mesh 



A Circular Garage for the Farm, 

 Built from Silo Forms 



SILO forms 

 previously 

 used on a Mis- 

 souri farm were 

 employed to 

 build the novel 

 circular concrete 

 garage shown in 

 the accompany- 

 ing illustration. 

 It cost about one 

 hundred and fif- 

 ty dollars and is 

 sixteen feet in 

 diameter, with 

 sufficient space 

 on each side of 

 the car for work 



bench and vise. It is entirely of concrete 

 except for the two-part wood doors and 

 window sash. The walls are four inches 

 thick, reinforced with wire netting. The 

 floor and the roof are also of concrete, the 

 latter with a three inch slope to the foot. 



Inflate Your Tires to Full Pressure, 

 Even in Hottest Weather 



OOK out! Don't inflate that tire 



"E 



this," is the costliest warning ever hurled 

 at motorists. Instead of saving 

 tires and money it has cost 

 automobile owners millions 

 of dollars. True, a tire does 

 expand in hot weather, but 

 so slightly as to be negligi- 

 ble in its effect. It never 

 expands to the danger 

 point. Furthermore, in- 

 ternal heat does not 

 result from the tem- 

 perature of the outside 

 air, but from the con- 

 stant bending of the tire 

 as it travels along. Con- 

 sequently, when you run 

 your tires under-inflated in 

 hot weather to combat air 

 expansion, you cause in- 

 creased bending of your 

 tires, and thus create more 

 heat — which is just the 

 condition to avoid. The 

 thing to guard against is 

 under-inflation. 



The measuring . device for de- 

 termining whether a person is 

 right or left handed naturally 



Use Your Natural Arm If You Would 

 Be a Good Craftsman 



THE brachiometer (don't be frightened 

 at the name) is an instrument which 

 has been devised by Professor H. Franklin 

 Jones, of the University of South 

 ikota, to determine whether an 

 individual is naturally right or 

 left handed. Every person is 

 born with a major and a 

 minor arm, and Professor 

 Jones, through study of 

 this fact, has discovered 

 things about the man 

 who is jack of all trades 

 and master of none. 



To determine "hand- 

 edness" he measures the 

 bones of the arm with 

 his brachiometer. If you 

 were born with a left 

 major but adopted the 

 right, the fact will be shown 

 by measurement of the re- 

 laxed forearm circumfer- 

 ence, contracted forearm, 

 relaxed biceps and con- 

 tracted biceps. To become 

 master of your trade you 

 must use your major arm. 



