232 ENGLISH MEN OF SCIENCE. [cHAr.
ingenious man may not be found who has ideas and much shrewdness, but is crotchety and impracticable. He wants energy and business habits, so he never rises. Many of these men brood over subjects like perpetual motion : their peculiarities are well illustrated in De Morgan's Book of Paradoxes. Again we frequently meet persons of a stamp that justifies the oldfashioned caricature of scientific. men, who are absorbed in some petty investigation, utterly deficient in business habits, and noted for absence of mind. Even idiots have often strongly quasi-scientific tastes, as love for simple mechanism, or objects of natural history ; and they have, as already remarked, a pleasure in collecting. Madmen have often persistency, as is shown by their brooding on a single topic. We all of us must have met with curious cases of failures, where a mind and disposition that promise much for success, never achieve it. It may be that some mental screw is loose, or there is some irreparable weakness of judgment, or some untimely irresolution or rashness ; any fault of this kind is sufficient to mar a man's