You know it occurred, because some one living next to the house saw him do it and told the owner, and the owner came to you for reparation and you charged the boy with it and he admitted it to be true. You are heartbroken because you find yourself confronted with what appears to be irrefutable evidence that your son is a bad boy. You ask him why he did it. He doesn’t know. You suggest that it might have been an accident. Being a truthful boy, he replies tearfully that it was not. You enquire if he had any grievance against the man who owns the house. He answers that he hadn’t even heard of the owner and didn’t know who he was. Then--you ask again--why did he do it? You get the same answer: “I don’t know.” It certainly looks dubious for your boy, madam, doesn’t it? If at the tender age of ten years a lad will deliberately “chuck” a stone through a neighbouring window, with no reason or provocation for it whatsoever, what may he not be capable of at twenty? The thought is appalling, isn’t it? Happily, however, I think it can be demonstrated to your complete satisfaction that your son is not bad--so far as this particular offence is concerned, anyway--and that this stone-throwing business is a perfectly natural thing for a perfectly normal boy to do. To start with, let us suppose that I have placed on your back fence, side by side, a brick and a bottle. I then hand you a little target-rifle and invite you to try your skill at shooting. Now, which will you aim at--the brick or the bottle? The bottle, of course. You answer more quickly than I can write it. And why the bottle? Just think that over a moment, please. Why the bottle? Meanwhile, let us go back to the boy and the window. The desire to see a physical result from any personal effort is deep-seated in every human being. Where is the author who does not take secret and real pleasure in scanning the achievements of his pen in the public print? Where is the architect who would forego the pleasure of seeing the finished structure, the lines and masses of which he has dreamed over and designed? The desire to see the result follow the endeavour, the effect follow the cause, is strong within us all. It may seem a far cry from art and letters to the boy and the broken window, but the psychologic principle involved is one and the same. The boy, sauntering along the street or the roadway, has been amusing himself by throwing stones. He has sent one against the side of a barn with no effect other than the sound of a hollow thud as it struck the boards. He has heaved one at a telegraph pole, and the pole didn’t even quiver. Then he spies the vacant house.