Why is it that of the whole surface of this globe, we may consider that three-fourths are covered by water, and that only one-fourth is in a condition to be permanently inhabited by human beings? Is there any great object in nature served by this? Is there any law of nature which would prevent the proportion being one-fourth water to three-fourths land, or even less water? In fact, what after all is the great use of water upon the large scale in nature? First of all, although three-fourths of the globe are now covered with water, there is no reason to suppose that it has been always so. On the contrary, it is quite certain that the proportion between land and water has changed very much and very frequently; that the whole continent of Europe was at one time the bed of an immense sea, when probably there was a great continent where the Pacific Ocean is now spread; that even Old Ireland was once not merely what Admiral Yorke wished her to be, forty-eight hours under water, but probably many thousand years in that condition; and that the great tract of limestone which occupies all the centre of the country, is nothing more than a collection of the skeletons of shell-fish, her first inhabitants, which by time and pressure have been converted into the hard material of which we build our houses, and which we burn into lime. There is thus no particular reason why there should be three times as much water at present as land, but it is easy to show that water on the great, as well as on the small scale, is of paramount importance in nature. Water is a portion of the food of all living beings. In the case of animals, the bodies from whence they derive nutriment are so varied and so complex, that to illustrate the peculiar part which water plays in each, would occupy too much space. In all our drinks, even in ardent spirits, there is a very large quantity of water, and our solid food very seldom contains less than nine-tenths of its weight of water. The living body is even less solid. A man weighing 150 lbs. would, if perfectly dried, weigh not more than 10 lbs., the other 140 lbs. being water. It is to the existence of this quantity of water that we owe the elasticity, the softness, and pliability of the different portions of our frame, the animal tissues being, when dry, hard and brittle as dry glue.