Unquestionably; and this constitutes the difference between _vaporization_ and _evaporation_. Water, when heated to the boiling point, can no longer exist in the form of water, and must necessarily be converted into vapour or steam, whatever may be the state and temperature of the surrounding medium; this is called vaporization. But the atmosphere, by means of the caloric it contains, can take up a certain portion of water at any temperature, and hold it in a state of solution. This is simply evaporation. Thus the atmosphere is continually carrying off moisture from the surface of the earth, until it is saturated with it. CAROLINE. That is the case, no doubt, when we feel the atmosphere damp. MRS. B. On the contrary, when the moisture is well dissolved it occasions no humidity: it is only when in a state of imperfect solution and floating in the atmosphere, in the form of watery vapour, that it produces dampness. This happens more frequently in winter than in summer; for the lower the temperature of the atmosphere, the less water it can dissolve; and in reality it never contains so much moisture as in a dry hot summer’s day. CAROLINE. You astonish me! But why, then, is the air so dry in frosty weather, when its temperature is at the lowest? EMILY. This, I conjecture, proceeds not so much from the moisture being dissolved, as from its being frozen; is not that the case? MRS. B. It is; and the freezing of the watery vapour which the atmospheric heat could not dissolve, produces what is called a hoar frost; for the particles descend in freezing, and attach themselves to whatever they meet with on the surface of the earth. The tendency of free caloric to an equilibrium, together with its solvent power, are likewise connected with the phenomena of rain, of dew, &c. When moist air of a certain temperature happens to pass through a colder region of the atmosphere, it parts with a portion of its heat to the surrounding air; the quantity of caloric, therefore, which served to keep the water in a state of vapour, being diminished, the watery particles approach each other, and form themselves into drops of water, which being heavier than the atmosphere, descend to the earth. There are also other circumstances, and particularly the variation in the weight of the atmosphere, which may contribute to the formation of rain. This, however, is an intricate subject, into which we cannot more fully enter at present. EMILY. In what manner do you account for the formation of dew? MRS. B. Dew is a deposition of watery particles or minute drops from the atmosphere, precipitated by the coolness of the evening. CAROLINE. This precipitation is owing, I suppose, to the cooling of the atmosphere, which prevents its retaining so great a quantity of watery vapour in solution as during the heat of the day. MRS. B.