The word cucumis used in the original of this passage embraces many of the cucurbitaceae, but the context shows that here means the cucumber.
The physical revolutions thus wrought by man have not indeed all been destructive to human interests, and the heaviest blows he has inflicted upon nature have not been wholly without their compensations. Soils to which no nutritious vegetable was indigenous, countries which once brought forth but the fewest products suited for the sustenance and comfort of man—while the severity of their climates created and stimulated the greatest number and the most imperious urgency of physical wants—surfaces the most rugged and intractable, and least blessed with natural facilities of communication, have been brought in modern times to yield and distribute all that supplies the material necessities, all that contributes to the sensuous enjoyments and conveniences of civilized life. The Scythia, the Thule, the Britain, the Germany, and the Gaul which the Roman writers describe in such forbidding terms, have been brought almost to rival the native luxuriance and easily won plenty of Southern Italy; and, while the fountains of oil and wine that refreshed old Greece and Syria and Northern Africa have almost ceased to flow, and the soils of those fair lands are turned to thirsty and inhospitable deserts, the hyperborean regions of Europe have learnod to conquer, or rather compensate, the rigors of climate, and have attained to a material wealth and variety of product that, with all their natural advantages, the granaries of the ancient world can hardly be said to have enjoyed.
Observation of Nature.
In these pages it is my aim to stimulate, not to satisfy, curiosity, and it is no part of my object to save my readers the labor of observation or of thought. For labor is life, and Death lives where power lives unused. [Footnote: Verses addressed by G. C. to Sir Walter Raleigh.—Haklutt, i., p. 608.]
Self is the schoolmaster whose lessons are best worth his wages; and since the subject I am considering has not yet become a branch of formal instruction, those whom it may interest can, fortunately, have no pedagogue but themselves. To the natural philosopher, the descriptive poet, the painter, the sculptor, and indeed every earnest observer, the power most important to cultivate, and, at the same time, hardest to acquire, is that of seeing what is before him. Sight is a faculty; seeing, an art. The eye is a physical but not a self-acting apparatus, and in general it sees only what it seeks. Like a mirror, it reflects objects presented to it; but it may be as insensible as a mirror, and not consciously perceive what it reflects. [Footnote: —I troer, at Synets Sands er lagt i Oiet, Mens dette kun er Redskab. Synet strommer Fra Sjaelens Dyb, og Oiets fine Nerver Gaae ud fra Hjernens hemmelige Vaerksted. Henrik Hertz, Kong Rene's Datter, sc. ii.
In the material eye, you think, sight lodgeth! The EYE is but an organ.
SEEING streameth from the soul's inmost depths. The fine perceptive
Nerve springeth from the brain's mysterious workshop.]
It has been maintained by high authority, that the natural acuteness of our sensuous faculties cannot be heightened by use, and hence, that the minutest details of the image formed on the retina are as perfect in the most untrained as in the most thoroughly disciplined organ. This may be questioned, and it is agreed on all hands that the power of multifarious perception and rapid discrimination may be immensely increased by well-directed practice. [Footnote: Skill in marksmanship, whether with firearms or with other projectile weapons, depends more upon the training of the eye than is generally supposed, and I have often found particularly good shots to possess an almost telescopic vision. In the ordinary use of the rifle, the barrel is guided by the eye, but there are sportemen who fire with the butt of the gun at the hip. In this case, as in the use of the sling, the lasso, and the bolas, in hurling the knife (see Babinet, Lectures, vii., p. 84), in throwing the boomerang, the javelin, or a stone, and in the employment of the blowpipe and the bow, the movements of the hand and arm are guided by that mysterious sympathy which exists between the eye and the unseeing organs of the body. "Some men wonder whye, in casting a man's eye at the marke, the hand should go streighte. Surely if he considered the nature of a man's eye he would not wonder at it: for this I am certaine of, that no servaunt to his maister, no childe to his father, is so obedient, as every joynte and peece of the bodye is to do whatsover the eye biddes."—Roger Ascham, Taxophilus, Book ii.
In shooting the tortoises of the Amazon and its tributaries, the Indians use an arrow with a long twine and a float attached to it. Ave-Lallemant (Die Benutzung der Palmen am Amazonenstrom, p. 32) thus describes their mode of aiming: "As the arrow, if aimed directly at the floating tortoise, would strike it at a small angle and glance from its fiat and wet shell, the archers have a peculiar method of shooting. They are able to calculate exactly their own muscular effort, the velocity of the stream, the distance and size of the tortoise, and they shoot the arrow directly up into the air, so that it falls almost vertically upon the shell of the tortoise, and sticks in it." Analogous calculations—if such physico-mental operations can property be so called—are made in the use of other missiles; for no projectile flies in a right line to its mark. But the exact training of the eye lies at the bottom of them all, and marksmanship depends almost wholly upon the power of that organ, whose directions the blind muscles implicitly follow. Savages accustomed only to the use of the bow become good shots with firearms after very little practice. It is perhaps not out of place to observe here that our English word aim comes from the Latin aestimo, I calculate or estimate. See Wedgwood's Dictionary of English Etymology, and the note to the American edition, under Aim.
Another proof of the control of the limbs by the eye has been observed in deaf-and-dumb schools, and others where pupils are first taught to write on large slates or blackboards. The writing is in large characters, the small letters being an inch or more high. They are formed with chalk or a slate pencil firmly grasped in the fingers, and by appropriate motions of the wrist, elbow, and shoulder, not of the finger joints. Nevertheless, when a pen is put into the hand of a pupil thus taught, his handwriting, though produced by a totally different set of muscles and muscular movements, is identical in character with that which he has practised on the blackboard. For a very remarkable account of the restoration of vision impaired from age, by judicious training, see Lessons in Life, by Timothy Titcomb, lesson xi. It has been much doubted whether the artists of the classic ages possessed a more perfect light than those of modern times, or whether, in executing their minute mosaics and gem engravings, they need magnifiers. Glasses ground convex have been found at Pompeii, but they are too rudely fashioned and too imperfectly polished to have been of any practical use for optical purposes. But though the ancient artists may have had a microscopic vision, their astronomers cannot have had a telescopic power of sight; for they did not discover the satellites of Jupiter, which are often seen with the naked eye at Oormeeah, in Persia, and sometimes, as I can testify by personal observation, at Cairo.]
This exercise of the eye I desire to promote, and, next to moral and religious doctrine, I know no more important practical lessons in this earthly life of ours—which, to the wise man, is a school from the cradle to the grave—than those relating to the employment of the sense of vision in the study of nature.