I left the High School at the end of 1820. I carried with me a small amount of Latin, and no Greek. I do not think I was much the better for my small acquaintance with the dead languages. I wanted something more living and quickening. I continued my studies at private classes. Arithmetic and geometry were my favourite branches. The three first books of Euclid were to me a new intellectual life. They brought out my power of reasoning. They trained me mentally. They enabled me to arrive at correct conclusions, and to acquire a knowledge of absolute truths. It is because of this that I have ever since held the beautifully perfect method of reasoning, as exhibited in the exact method of arriving at Q.E.D., to be one of the most satisfactory efforts and exercises of the human intellect.

Besides visiting and taking part in the works at Patterson's foundry, and joining in the chemical experiments at Smith's laboratory, my father gave me every opportunity for practising the art of drawing. He taught me to sketch with exactness every object, whether natural or artificial, so as to enable the hand to accurately reproduce what the eye had seen. In order to acquire this almost invaluable art, which can serve so many valuable purposes in life, he was careful to educate my eye, so that I might perceive the relative proportions of the objects placed before me.