contraction without limit, a great portion of the earth would be bound in fetters of

ice. Such a disastrous result, is prevented by the substitution of expansion for contraction, when the temperature is reduced to 40°, and the benevolent purposes of an

all-wise Designer, are made still more manifest by the further expansion of water in

the act of freezing. As water becomes ice by cold, it becomes steam by heat. We generally understand by steam the vapor of hot water, but steam or vapor rises from

water at all temperatures, however low, and even from ice. The expansive force of this vapor increases rapidly as the heat increases, but yet in all cases the surface of

water is covered with an atmosphere of aqueous vapor, the pressure, or tension of

which is limited by the temperature of the water. If, therefore, the vapor is not

confined, causing the surface of water to be pressed upon, evaporation will take

place, and thus there must, according to this law, always exist an atmosphere of

aqueous vapor, the tension of which may be compared with that of our common atmosphere. Now the pressure of the latter is measured by the barometrical column, about 30 inches of mercury, while that of watery vapor is equal to one inch of mercury at the constituent temperature of 80 degrees, and to one fifth of an inch at the temperature of 32 degrees. If the atmosphere of air by which we are supported were annihilated, there would still remain, an atmosphere of aqueous vapor, arising from the waters and moist parts of the earth, but in the existing state of things this vapor rises in the atmosphere of dry air, and thus its distribution and effects are materially influenced by the vehicle in which it is thus carried.