At the same time he was training his powers of thought by an assiduous study of algebra and geometry.

The absorbing hours he spent over his Euclid were apparently of no use to him in his profession; but Lincoln was in his way an intellectual gymnast and enjoyed the exertion for its own sake.

Such a use of his leisure must have seemed a sheer waste of time to his more practical friends, and they might well have accounted for his comparative lack of success by his indulgence in such secret and useless pastimes.

Neither would this criticism have been beside the mark, for if Lincoln's great energy and powers of work had been devoted exclusively to practical ends, he might well have become in the early days a more prominent lawyer and politician than he actually was.

But he preferred the satisfaction of his own intellectual and social instincts, and so qualified himself for achievements beyond the power of a Douglas.
In addition, however, to these private gymnastics Lincoln shared with his neighbors a public and popular source of intellectual and human insight.