842 



Popular Science Monthly 



fcs^, T' 



© Kimt rr.-«< Assn. 



The fan spins like a great pin-wheel when the aeroplane is 

 under way and produces the power to drive the dynamo 



Making the Aeroplane Generate Its Own 

 Power for Wireless 



TELF-:GRAPHINC; from aeroplanes by 

 wireless has become an ordinary oc- 

 currence in the European war zone. But 

 some trouble has been encountered in 

 securing tlie power to send the messages. 

 The wireless transmitter on an aero- 

 plane must, of necessity, be very light 

 and compact, liut it does not require 

 a great amount of power. 



Batteries are not regarded fa\orably 

 for the purpose because it is practically 

 impossible to send messages far with- 

 out increasing the number and size 

 of the batteries until their weight 

 becomes prohibitive. A few of 

 light weight will not prod 

 sufficient voltage. 



By far the best plan tcstci 

 thus far involves the use of 

 a small dynamo which 

 generates directly the al- 

 ternating current neces- 

 sary. It is arranged to 

 be dri\'en through gears 

 or by a belt from the 

 main gasoline motor of 

 the aeroplane. Or it 

 may I)e dri\eii indirectl>' 

 iiy means of an "aerofan" 

 as shown in the illustra- 

 lioii. 'l"his fan spins like 

 a great pin-wheel wlien 

 the aeroplane is uncler 

 way, producing power 

 to drive the dvnaino. 



Tlie novel device for 

 dividing the profits 

 between the owner 

 and the lessee, and 

 for tlic rejection of 

 spurious coin sluns 



An Unusually Fair-Minded 

 Slot Machine 

 HE weighty cjuestion of 

 the gain or loss of 

 a\-oirdupois which is so often 

 asked of the slot machine, 

 may henceforth be brilliantly 

 answered by an automatic 

 elect rirally-operated beam- 

 scale, which is claimed to be 

 \ cry accurate and practically 

 infallible in its measurements. 

 The machine is coin-operated 

 and possesses many novel fea- 

 tures. 



When the person to be 

 weighed steps upon the plat- 

 form and drops a coin into the 

 slot, a small interior electric 

 light is turned on and the 

 large weight mov'es to the 

 proper position on the bal- 

 ance-lever. Then the small weight which 

 measures pounds and fractions of pounds 

 moves out to the balancing position and 

 stops. The balancing weights are drawn 

 along the beams by small motors which 

 are automat icalh' cut off wlu-n the beam 

 balances. Tin- interior light enables the 

 I)atron to read clearly 

 tiie weight indicated. 

 The in\'cntion also 

 embodies a novel per- 

 centage-paying de- 

 vice, separating the 

 cash into two cash 

 boxes, one intended for the 

 profits resulting to the place 

 of business where the 

 machine is being operated 

 and the other for the owner 

 of the machine. When the 

 owner's slot is filled, the 

 next coin is diverted into 

 the lessee's cash liox and 

 in its course strikes a trig- 

 ger whicii releases the 

 owner's casii into its sepa- 

 rate box. 



The machine, moreover, 

 displa\'s almost human in- 

 telligence in the discrimi- 

 n. it ion which it makes be- 

 tween the genuine 

 coin of the realm and 

 counterfeits or slugs, 

 ni\ariabl\- handing 

 back to the customer 

 an\- substitution. 



