with the most disinterested love.

Consider-Secondly: It is enjoined by the world's greatest Benefactor. He Himself has enjoined it; "Do this in remembrance of me," and this command He gave under the most touching circumstances. How amazing it is that men should neglect it!

The excuses that men make for neglecting this are singularly absurd. A man will sometimes say, "I can be

Scripture and Science.

(No. II.)

SUBJECT: Dew and Hoar Frost.

A.-The facts of Science bearing on these subjects.

Material objects are composed of a number of atoms in a state of combination, as water, which is composed of two atoms of hydrogen and one of oxygen (H2O); or common salt, which is formed of one atom of sodium and one of chlorine (NaCl). These atoms have, themselves, not the properties of the compound, but when they combine as atoms, the resulting compound must be very small. The quantity of water denoted by the symbol H2O is probably not the millionth part of a drop; still it has all the properties of water. This minutest part of water is called a molecule. These molecules are of various shapes, and adhere to each other with various degrees of tenacity, as seen in solids, liquids, and gases. In no case are they in actual contact, nor are they ever found having, for a long time together, the same relative position. Like water in the sea, they are always in a state of motion. These motions are of various kinds, but I wish to speak of one, the motion which gives to the touch the sensation of heat. Really, the molecules are simply moving among themselves, and becoming more distant from each other. This motion expands the body whose constituent parts these molecules are, and renders it less in specific gravity. These molecules, though too small

to be seen by the strongest microscopic power, move, not in straight lines, but in spirals, as if along the threads of a screw; that of water being thirty times as fine as that of lead or mercury. When the molecules of water have reached the distance from each other at which they always stand when the thermometer stands at 212 deg. Fahr., the substance assumes the form of steam or vapour, and, being of less specific gravity than the atmosphere near the surface of the earth, it rises until a stratum is reached whose specific gravity is equal to its own.

The evaporation of water is thus seen to be caused by the separation of its molecules by a force which we name heat. The heat of the sun expands the superficial layer of the sea and lakes, and causes the water to rise and float in the air in the form of vapour. When the temperature is sufficiently high the vapour becomes transparent and invisible. This is explained by supposing its molecules, which are seen only when many are together, to become isolated. A diminution of temperature, by the setting of the sun, lessens their centrifugal tendency, and brings them sufficiently near together to be seen again in the form of vapour. These minute globules of vapour fall upon the grass of the field and the trees of the forest, and, uniting with each other, under the influence of gravitation, they form drops of clear and pure water, and hang like tears upon the closing eyelids of the flower. These drops are known as dew, and appear because the heat of the sun evaporates the water, and the cold of the night lessens the expansive force which separates the aqueous molecules, and thus condenses the vapour, unites the molecules into groups, which are sufficiently large to affect our organs of vision.

In the case of sea, and any other water which holds mineral substances in solution, the molecules of the mineral are held between those of the fluid element, but in the process of evaporation the molecules of water are separated from each other, and thus the mineral particles are set at liberty, and being themselves of greater specific gravity than the air, they are left behind, and the clear water, free from all mineral impurities, alone, rises to the clouds, and then condenses into rain, or rises into imperceptible vapour, and then condenses into dew.

The existence of invisible vapour of water in the atmosphere, and the lowering of the temperature to the condensing point, are the two only conditions of dewfall. The former condition is daily fulfilled by the heat of the sun, and especially in the summer or in tropical regions; the latter by the radiation of heat by objects on the surface of the earth.

Equilibrium of forces is the only condition of stability. A body in motion will ever move, unless its moving force be counterbalanced by another equal and opposite. In nature there is a constant effort to attain a state of repose or equilibrium, but that state is approached by

the law of oscillation.

A pendulum in motion seeks to rest in a position in the straight line which joins the centre of the earth with its point of suspension, but, in coming to this place, it comes with too much force, and first of all passes over it to the opposite side.

Objects, whose temperature is different, placed at any distance from each other-though only seen by us when they are near-seek a state of repose. The heat of the hotter flies off in the direction of the colder, to bring it up to a common standard. The colder object is warmed and the hotter is cooled, until at length both have equal temperature; or, to speak more in harmony with modern science, the molecules which move faster and at a greater distance from each other, communicate their motion to those in the other objects, which are more sluggish, until the ultimate particles of both have attained a common velocity. The hotter object in becoming cool goes at first beyond the point of equality, and becomes the colder of the two. The other then begins to heat its neighbour, and both, after many oscillations, arrive at a state of repose, or of equal temperature.

Some substances part with their heat by radiation, much more quickly than others. Grass radiates heat, and thus cools much more quickly than earth or stone, or wood or metal.

When the sun has ceased to heat the grass or ground, or space being colder than the atmosphere, the latter begins to radiate or send forth its heat to the colder region. The air becoming colder than the ground, the latter pours forth its heat to restore the equilibrium of temperature. But owing to the law of oscillation, the ground becomes ultimately colder than the atmospheric stratum nearest to its surface, and owing to the motion of the air a little further from the ground, the strata above become warmer than those below. The stratum in which the grass grows, and in which the trees wave their foliage, becomes too cold to hold the vapour molecules at a distance from each other. Their speed is slackened, and many of them coalesce so as to become too heavy to float in a mere mechanical mixture of gases, such as the atmosphere is. They gently sink and rest upon the grass below, and, uniting in larger groups, they form the glittering drops which dance in the moonlight on the quivering leaf, and sleep in the warm bosom of the flower.

If, however, the air moves much, and moves near the ground, as motion is heat in another form, the requisite cold temperature is not attained, for the condensation of invisible vapour, and no dew falls.

If a screen of wood, or glass, or thinnest gauze be placed above the grass, the heat, radiated by the earth and its covering of vegetation, strikes the screen, and, though some be absorbed, a large portion is reflected back again, and the temperature never becomes low, and the dew is not deposited under these conditions. The clouds are

screens above the ground, which reflect back to the earth again the heat it lost by radiation. No dew is formed, therefore, on a cloudy night. The clearer the sky, other things being equal, the more copious the fall of dew.

Hoarfrost is dew solidified or frozen, and is formed of an indefinite number of crystals, whose beauty must be seen to be conceived.

One more fact must not be forgotten. If a piece of ice be taken, whose temperature is 32 deg. Fahr., and heat applied to it, much heat will be consumed to melt the ice and make it water, and yet, notwithstanding the consumption of all that heat, the temperature of the water is but 32 deg. Again, when water boils, its temperature is 212 deg. Fahr., and an immense amount of heat is used in the conversion of water into steam or vapour, and yet the temperature of steam at the first is only equal to that of boiling water-212 deg. The heat absorbed in either case becomes imperceptible or latent. The law is this-When a solid becomes liquid, it absorbs heat, and when a liquid assumes the form of vapour heat disappears. Evaporation is therefore cooling. The heat of a burning sun is counteracted in its injurious consequences by cold produced by the absorption of heat in the process of evaporation.

The result of condensation is the reverse of this. The heat absorbed on a hot day by the change of water into invisible vapour is given back again, without change or diminution, when that vapour becomes the pearly dew; and the heat absorbed by the ice in becoming water is set at liberty to warm the world on the cold night when the dew becomes hoar frost.

B.-Special points of interest in these facts.

Dew (a) is the purest water in nature, being free from mineral impurities. Rain water, owing to the disturbed action of the atmosphere, when it falls, contains carbonate of ammonia, and during a thunderstorm nitrate of ammonia and other impurities. Dew (¿) is the result of a combination of the smallest aqueous molecules; (c) falls plentifully when there is no rain, there being no clouds; (d) falls only when the air is chill; (e) never falls copiously on hard or metallic substances, because these are bad radiators of heat; (f) falls only when the air is still; (g) when the sky is clear, (h) chiefly in the night; (i) falls most plentifully on those objects which are nearest the surface of the earth. Dew in the act of forming (k) gives out heat, and thus warms the night air, and keeps alive the growing vegetation. Dew in freezing, or in becoming hoar frost, gives forth the greatest heat, and that when the night is coldest and the vegetation needs its protecting influence the most: this is hoar frost.

C-Application of these facts to some of the texts of Scripture. Conscious of the difficulty of revealing heavenly and spiritual