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.
Here the width between the trees A and B will seem to be as great as the line AB: But the width between the trees C and D will seem to be no more than EF.
Q. In a long straight street, why do the houses seem to approach nearer and nearer as they are more distant?
A. Because the more distant the houses are, the more acute will be the angle which any two make with our eye.
Thus in the last figure—