114 



FOR BETTER CROPS 



and it is found that no spark is made. This is because the 

 binding- post in the ignitor is insulated from the engine. Swing 

 the trip on the ignitor around until you feel it strike something 

 on the inside of the engine, then snap the wire across the bat- 

 tery, and again the spark is made. This is because the movable 

 part of the ignitor has come in contact within the engine with 

 the insulated binding post, and a circuit is made through the 

 inside of the engine. Leave both wires connected to the bat- 

 tery and snap the trigger on the ignitor, and you make a spark 

 within the engine the same as you did on the battery when you 

 held the trigger around so that contact was made through the 

 inside of the engine. If you do not believe this, take the ignitor 

 out and lay it on some bright part of the engine and try it. 

 While you have the ignitor out put some water between the 



Filling the silo 



points and then snap it and see if you get a spark. You do not, 

 because the water bridges the gap between the points, and being 

 a conductor of electricity, the circuit is not broken. Put some 

 oil between the points and try it. No spark is made in this 

 case because the oil is a non-conductor of electricity, and the 

 circuit was not made, hence could not be broken. 



These illustrations show that if a non-conductor gets between 

 the points of the ignitor a spark is not made, and if a conductor 

 gets across the points a spark is also not made, hence it is abso- 

 lutely essential that the ignitor and all binding posts be kept 

 clean, and the latter must be kept tight. 



Since gasoline gas does not burn instantly, ignition should 

 take place some time before the piston reaches dead center. 

 This point is generally determined by the position of the crank 

 and the speed of the engine. A slow speed engine should ignite 



