380 DISTANCE. 



Here the arrow A held close to the candle, will cast 

 the shadow BF on the wall: while the same arrow held 

 at C, would cast only the little shadow D E. 



Q. When we enter a long AVENUE of TREES, 

 WHY does the avenue seem to get NARROWER and 

 narrower till it appears to MEET ? 



A. Because the further the trees are 

 off, the more acute will be the angle that 

 any two will make with our eye. 



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rl .."" 



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Here the width between the trees A and B will seem 

 to be as great as the line A B : 



