210   Life anal Letters of Francis Galton

its characteristics. These fallow years show the dominance of determinants of which- we are fully conscious in tracing Galton's family history, but which after 1850 play only a subordinate, albeit a graceful part in his character and activities. In 1849 Galton's mechanical tastes revived and his scientific bent came once more to its rights. When the " spring-fret " again came o'er him, he knew his " naked soul " and had found, a congenial purpose in life.

In the failure of any record of environmental influence', we can only attribute the difference between the Soudanese and the Central African journeys to the not unfamiliar experience of different hereditary tendencies developing potency at successive stages of an individual's growth. Charles Darwin was a student and naturalist from his College days ; Francis Galton's six fallow years threw back his work in life, so that much of it was achieved at an age when most minds grow quiescent. But the delay was not greatly to his, nor, in the long run, to the public disadvantage. His earlier papers on the improvement of the human race by conscious selection were nearly stillborn, they faced a world quite unripe for the ideas Galton had to teach. The acceptance of the principle of Natural Selection and the recognition of .science as - a capital authority in human affairs had to make marked progress before Galton's teaching could reach its audience, and produce -its effect.

1 We know how the publication of the Origin of Species moved Francis Galton. At first it. seemed to the writer of this biography that the voyage of the " Beagle " might have turned Galton's thoughts to scientific travel, but the Journal of that voyage

appeared in 1837, five or six years after the voyage, and there is no reference to it in Galton's letters of that date or later. The famous Linnaean Society publication made jointly with Wallace dates from 1858, when Galton had already settled down to

scientific work.