The Necessity of Water to Man.--Composition of the Human Body.--Natural and Artificial Distillation.--The Traveller’s Tree.--Pitcher-plants and Monkey-pots.--Stomach of the Camel, and its Analogy to the Honey-comb.--Dewdrops.--Use of the Still at Sea.--Perspiration and its cooling Properties.--The Turkish Bath.--Perfume and Ether Spray.--Condenser of the Low-pressure Steam-engine.--The Dry and Wet Bulb Thermometer.--Ice produced in a red-hot Vessel.--Power of Water.--How Fountains are made.--Modern System of Hydrants.--Hydraulic Mining.--The Victoria and Niagara Falls.--Artesian Wells.--The Norton Tube, &c., in Abyssinia.--The Water-ram and Spout-hole. IT has often been remarked that man can live a comparatively long time without solid food, providing that he can only obtain water, of which the chief bulk of the human body is made. Dying by thirst is a horribly painful death, but, according to Mr. Mills, the ill-fated Australian traveller, “starvation on nardoo (an innutritious plant) is by no means unpleasant, but from the weakness one feels, and the utter inability to move one’s self.” Those who have been shipwrecked, and unable to obtain fresh water, have always found that the tortures of thirst were infinitely harder to endure than those of hunger; and the reader will probably remember that those who perished in the Black Hole of Calcutta owed their deaths chiefly to thirst, their bodies being exhausted of moisture by the heat of the room, and no fresh supply attainable. Civilisation especially shows itself in the way in which water is brought within the reach of every one, even in the most crowded of cities. The reader may probably call to mind the wonderful aqueducts of ancient Rome, the gigantic remains of which still exist. Then, as to our own country, we are all practically acquainted with some water company, by which the water, more or less purified, is brought into our houses, and can be obtained by the mere turning of a tap. Yet all this ingenuity is but a following of natural prototypes, as will presently be seen; and even the familiar Water-tank, as shown at the right hand of the illustration, has been anticipated by Nature. * * * * * ON the left hand of the illustration there are three examples of natural water-tanks, two belonging to the vegetable, and one to the animal kingdom. [Illustration: TRAVELLER’S TREE. STOMACH OF CAMEL. PITCHER-PLANT. CISTERN.] That on the extreme left, with a number of radiations, represents a portion of a Madagascar palm, popularly called the Traveller’s Tree. Having very large leaves, arranged in the manner there shown, the Traveller’s Tree condenses the nightly dews, and allows them to trickle down into the hollows of the leaf-stems.