Stereo Copyright, Underwood & UnderwoodLondon and New York
Cotton-fields in Georgia, U.S.A.
Negroes picking the cotton harvest.
The classical person above alluded to seems to have copied the bird's wing, sticking on feathers with wax, which of course melted in the sun with the usual result to the inventor of flying machines. Many seeds have regular wings which act like those of the bat or flying squirrel. One of the most exquisite of all is the seed of Bignonia. The Dahlia fruit has also a flying wing, and a great many others might be mentioned. Major Baden-Powell experimented with kites, which were supposed to raise a man high enough in the air to take observations of the enemy's movements. But a most exquisite "kite" is that of the Lime tree. The little fruit is hung from a broad, flying bract, and as it very slowly sinks to the ground it solemnly turns round and round. That is because the pressure of the air acts on the flat bract just as it does on an aeroplane, and forces it to revolve. So the fruit remains a long time in the air, and may be carried to nearly a hundred yards away from its parent tree.
The Traveller's Joy (Clematis) and the Cotton have their seeds covered all over by many entangled hairs, which act like a piece of fluff, so that the wind blows the seed away.
No one has discovered the original wild Cotton plant. The robes of the priests in Egyptian temples were made of it. It was introduced into Spain by the Arabs when they invaded that country. When the Spaniards attacked the half-civilized Indian people of Central and South America, they found cotton was regularly cultivated there. Its history in England is rather interesting. In the days of Queen Elizabeth the great English industry was the production of woollen cloth from Yorkshire sheep. A penalty of £20 was imposed, even as late as 1720, on any person who imported or even wore cotton cloths. Yet this was unable to stop the growth of the trade which, thanks to the Flemings and Huguenots who took refuge from religious persecution in this country, eventually became our gigantic textile industry employing millions of factory hands.
The advantage of these wings and hairs is at once seen if one compares the time that a fruit or seed takes to fall through a given height, first with its wings or hairs, and then after they have been cut off.
An Artichoke fruit, for instance, will take nearly eight seconds to reach the ground from a height of a few feet. But if you cut away its hairs, it will touch the ground in a little more than one second. A Sycamore fruit of which the wing has been removed falls to the ground in about a quarter of the time that it takes when it has not been injured, so that the wing helps it to fly to four times the distance that it could reach if it had none. The Ash fruit also remains twice as long in the air as it would do if it had no wing; and so on.
We shall finish this chapter by describing two very extraordinary cases.
The Sandbox tree is a native of tropical America. The fruit, as large as an orange, consists of a number of rounded pieces, each with a single seed inside. When ripe each piece splits off, making a noise like the report of a pistol. The plant is sometimes called the Monkey's Dinner Bell. These pieces may be thrown to a distance of fifty-seven feet from the parent plant.