others' inclinations. Sent to read law at sixteen, he managed, after the day's studies, to pursue his astronomical observations, passing whole nights in his favorite occupation. Newton, like Galileo, occupied his playhours at school with constructing model machines (water-clock, windmill, etc.). By the age of twenty-three or twenty-four he had conceived roughly his chief epoch-making discoveries. Another English investigator, Thomas Young, was a striking example of precocity. He read with fluency at two. He showed extraordinary avidity of mind in very different directions, now busy mastering the difficulties of Oriental languages, now set on constructing a microscope for himself. His mind, unburdened with its weight of learning, was nimbly tracking out new truths in optics by the age of twenty-nine.
Recent English biography supplies us with two of the most signal illustrations of the precocity of the mathematical mind, viz., Clerk Maxwell and Sir William Rowan Hamilton.
Among naturalists, too, examples of well-marked if less astonishing precocity are to be met with. Linnæus as a boy showed so decided a bent to botany that, through the advocacy of a physician who had remarked the early trait, he was saved from the shoemaker's shop, for which his father had destined him, and secured for science. At the age of twenty-three we find him lecturing on botany, and superintending a botanical garden, and at twenty-eight he begins to publish his new ideas of classification. Cuvier's history is similar. A poor lad, he displayed an irresistible impulse to scientific observation, and by twenty-nine published a work in which the central ideas of his system are set forth. Humboldt, again, showed his special scientific bent as a child. From his love of collecting and labeling plants, shells, and insects, he was known as "the little apothecary." At twenty he published a work giving the results of a scientific journey up the Rhine. In medicine, Haller is a notable instance of precocity.
Since Science has academical and other appointments to bestow on her distinguished votaries, we may estimate the precocity of scientific men by noting the early age at which such posts have been won. Laplace was mathematical teacher at a school when a mere lad; Lagrange was professor at eighteen; St. Hilaire at twenty-one; Kepler, Euler, Linnæus, and Davy at twenty-three; Cuvier at twenty-six; Copernicus at twenty-seven; and Tycho Brahe at twenty-eight. Others have obtained academic honors at an early age; among these, Lavoisier, Lyell, and Clifford.
Following our general plan, we have to ask what proportion of eminent savants have shown signs of precocity. I find, after going through a list of thirty-six, that twenty-seven, or three fourths, have given distinct evidence of a bent to science before twenty. Of the remaining nine, five appear to have first taken to science after this age, while in the case of four the question is left doubtful.
Looking now at the age of productivity, we obtain the following
