A cousin to Charles Darwin, Francis Galton, is an investigator of eminence. In a study of visual memory, a faculty in which observation bears its best fruits, he says:--
“It is a mistake to suppose that sharp sight is accompanied by clear visual memory. I have not a few instances in which the independence of the two faculties is emphatically commented upon; and I have at least one clear case where great interest in outlines and accurate apprehension of straightness, squareness, and the like, is unaccompanied by the power of visualizing.”
A new instrument, machine or engine is imagined by its creator long before it takes actual form; everything he sees that will be of help he builds at once into his design, everything else, however interesting in itself, he passes with a heedless eye.
“If we think birds, we shall see birds wherever we go,” says John Burroughs. An observer faithful and accurate in noticing birds and beasts, rocks and leaves, may come at last upon a flower which opens a sphere of knowledge wholly new, as when the round-leaved sun-dew was first observed to entrap and feed upon insects. Much, also, depends upon comparisons such as occur only to a mind at once broad and alert. One may notice in spring and early summer a few leaves growing directly from the trunk of a tree, sometimes near the ground. In maples these leaves are decidedly narrower than those growing from branches in the usual way, and they often have a reddish tinge. Comparing a variety of such leaves with fossil impressions of allied species, Professor Robert T. Jackson of Boston came upon an interesting discovery. He found that these sporadic leaves closely resemble those borne by the remote ancestors of our present trees: they are the lingering reminders of a far distant day.
An observation equally keen saved the orange groves of California from destruction by the fluted scale insect. In 1890, or thereabout, the orange growers in their extremity sought the advice of Professor C. V. Riley, entomologist to the Department of Agriculture at Washington. He asked: “Where did the pest come from?” “Australia,” was the answer. “Is it much of a nuisance there?” “Not particularly.” “Then what keeps it down, what preys upon it?” “Nothing specially,” was the response. Dissatisfied with this answer, Professor Riley sent to Australia a trained entomologist and acute observer, Mr. Albert Koebele, who gathered various insects noticed as preying upon the fluted scale. Distributing these upon his arrival in California he was fortunate enough to find that one of his assisted emigrants, a lady bird, _Vedalia cardinalis_, fed so ravenously upon the fluted scale as to restrict its ravages to quite moderate proportions.