On the other hand, he developed great intelligence as regards the PRACTICAL aspect of life.

In a trice he divined and comprehended how things ought to be worked, and, from that time forth, bore himself towards his school-fellows in such a way that, though they frequently gave him presents, he not only never returned the compliment, but even on occasions pocketed the gifts for the mere purpose of selling them again.
Also, boy though he was, he acquired the art of self-denial.

Of the trifle which his father had given him on parting he spent not a kopeck, but, the same year, actually added to his little store by fashioning a bullfinch of wax, painting it, and selling the same at a handsome profit.

Next, as time went on, he engaged in other speculations--in particular, in the scheme of buying up eatables, taking his seat in class beside boys who had plenty of pocket-money, and, as soon as such opulent individuals showed signs of failing attention (and, therefore, of growing appetite), tendering them, from beneath the desk, a roll of pudding or a piece of gingerbread, and charging according to degree of appetite and size of portion.

He also spent a couple of months in training a mouse, which he kept confined in a little wooden cage in his bedroom.