He was three inches taller than his father.

Was it possible that any man could grow to be three inches taller than Mr.Pendennis?
You may be certain he never went back to school; the discipline of the establishment did not suit him, and he liked being at home much better.
The question of his return was debated, and his uncle was for his going back.

The Doctor wrote his opinion that it was most important for Arthur's success in after-life that he should know a Greek play thoroughly, but Pen adroitly managed to hint to his mother what a dangerous place Greyfriars was, and what sad wild fellows some of the chaps there were, and the timid soul, taking alarm at once, acceded to his desire to stay at home.
Then Pen's uncle offered to use his influence with His Royal Highness the Commander-in-Chief, who was pleased to be very kind to him, and proposed to get Pen a commission in the Foot Guards.

Pen's heart leaped at this: he had been to hear the band at St.James's play on a Sunday, when he went out to his uncle.

He had seen Tom Ricketts, of the fourth form, who used to wear a jacket and trousers so ludicrously tight, that the elder boys could not forbear using him in the quality of a butt or 'cockshy'-- he had seen this very Ricketts arrayed in crimson and gold, with an immense bear-skin cap on his head, staggering under the colours of the regiment.