for instance, the warmer the air, the more it will absorb, the less the pressure on the air, the more it will absorb, and the drier the air, the more it will absorb, that is, the less moisture it has already got, the more will be required to make up that quantity which the other circumstances permit it to contain. Now, what takes place if a warm, dry, light current of wind blows over the sea, landward? Why, all the vapour given off by the sea, to the amount of millions of gallons, is absorbed and carried inland by the wind or current of the air, and this continues onward, laden with moisture, until it meets with one of the several circumstances which shall cause it to be incapable of holding the quantity of moisture which it has already got; for instance, it meets with another current of air colder than itself, these mingle, the vapour of water is condensed by the cold, and a cloud is formed. This consists of minute particles of water suspended in--not absorbed by--air; these particles gradually collect, and down falls the rain on to the earth. This drains off from the surface, forming rills, which collect as they descend, by their own weight, into the lowest channels of the ground, and form into streams and rivers, and back into the sea comes the water which the air had taken away, with this difference, that it is free from salt and fit for the many uses to which fresh water alone can be applied; when the vapour rises from the sea, none of the saline matters rise with it, for, although the water is volatile, yet they are not, and this is the whole source of fresh water. It is distilled in the great laboratory of Nature, and gives nourishment to all the living beings who dwell on the land and in the rivers and lakes; or the rain may sink into the earth and be carried for miles and miles under ground, running through some porous stratum, such as gravel, until it flows out in the form of a spring, bubbling up amongst flowers and weeds, and forming the source of some river, which receiving the rain and all the springs in the country through which it flows, finds its way back into the ocean at last. [Illustration: MOUNTAIN STREAM.]