Brown minor gets to work. He takes a portion of the crystalline substance and heats it red-hot, in the hope that it will explode; and treats another with concentrated sulphuric acid in order to stimulate it into some interesting performance. At the same time he maintains a running fire of _sotto voce_ conversation and chaff with his neighbours--a laboratory offers opportunities for social intercourse undreamed of in a form-room--and occasionally leaves his own task in order to assist, or more often to impede, the labours of another. When he returns to his place he not infrequently finds that his last decoction (containing the balance of the crystalline substance) has boiled over, and is now lying in a simmering pool upon the bench, or that another chemist has called and appropriated the vessel in which the experiment was proceeding, emptying its contents down the sink. Not a whit disturbed, he fills up the time with some work of independent research, such as the manufacture of a Roman candle or the preparation of a sample of nitro-glycerine. At the end of the hour he reports progress to his instructor, expressing polite regret at having failed as yet to solve the riddle of the crystalline substance; and returns whistling to his form-room, where he jeers at those of his companions who have spent the morning composing Latin Verses. No, it is a mistake to imagine that the young of the human animal hungers and thirsts after knowledge. * * * * * Arthur Robinson, B.A., of whom previous mention has been made, soon discovered this fact; or rather, soon recognised it; for he was not much more than a boy himself. He was an observant and efficient young man, and presently he made further discoveries. The first was that boys, for teaching purposes, can be divided into three classes: (_A_) Boys whose conduct is uniformly good, and whose industry is continuous. Say fifteen per cent. For example, Master Mole. He was invariably punctual; his work was always well prepared; and he endured a good deal of what toilers in another walk of life term "peaceful picketing" for contravening one of the fundamental laws of schoolboy trades-unionism by continuing to work when the master was out of the room. (_B_) Boys whose conduct is uniformly good--except perhaps in the matter of surreptitious refreshment--but who will only work so long as they are watched. Say sixty per cent. Such a one was Master Gibbs. By long practice he had acquired the art of looking supremely alert and attentive when in reality his thoughts were at the back of beyond. When engaged in writing work his pen would move across the page with mechanical regularity, what time both eyes were fixed upon a page torn from a comic paper and secreted under his manuscript. He gave no trouble whatever, but was a thorn in the flesh of any conscientious teacher. (_C_) Boys who are not only idle, but mischievous. Say twenty-five per cent.