enormous pressure, to have the resulting crystal as compact as a diamond.

The force of crystallization is used by us in many inferior ways, as in making crystals of rock candy, sulphur, salt, etc., but for the making of diamonds it is too much for us, except in a small way.

While we cannot yet use the force that builds large white diamonds we can use the diamonds themselves. Set a number of them around a section of an iron tube, place it against a rock, at the surface or deep down in a mine, cause it to revolve rapidly by machinery, and it will bore into the rock, leaving a core. Force in water, to remove the dust and chips, and the diamond teeth will eat their way hundreds of feet in any direction; and by examining the extracted core miners can tell what sort of ore there is hundreds of feet in advance. Hence, they go only where they know that value lies.

SOME CURIOUS BEHAVIORS OF ATOMS

Ultimate atoms of matter are asserted to be impenetrable. That is, if a mass of them really touched each other, that mass would not be condensible by any force. But atoms of matter do not touch. It is thinkable, but not demonstrable, that condensation might go on till there were no discernible substance left, only force.

Matter exists in three states: solid, liquid, and gas. It is thought that all matter may be passed through the three stages--iron being capable of being volatilized, and gases condensed to liquids and solids--the chief difference of these states being greater or less distance between the constituent atoms and molecules. In gas the particles are distant from each other, like gnats flying in the air; in liquids, distant as men passing in a busy street; in solids, as men in a congregation, so sparse that each can easily move about. The congregation can easily disperse to the rarity of those walking in the street, and the men in the street condense to the density of the congregation. So, matter can change in going from solids to liquids and gases, or vice versa. The behavior of atoms in the process is surpassingly interesting.

Gold changes its density, and therefore its thickness, between the two dies of the mint that make it money. How do the particles behave as they snuggle up closer to each other?

Take a piece of iron wire and bend it. The atoms on the inner side become nearer together, those on the outside farther apart. Twist it. The outer particles revolve on each other; those of the middle do not move. They assume and maintain their new relations.

Hang a weight on a wire. It does not stretch like a rubber thread, but it stretches. Eight wires were tested as to their tensile strength. They gave an average of forty-five pounds, and an elongation averaging nineteen per cent of the total length. Then a wire of the same kind was given time to adjust itself to its new and trying circumstances. Forty pounds were hung on one day, three pounds more the next day, and so on, increasing the weights by diminishing quantities, till in sixty days it carried fifty-seven pounds. So it seems that exercise strengthened the wire nearly twenty-seven per cent.

While those atoms are hustling about, lengthening the wire and getting a better grip on one another, they grow warm with the exercise. Hold a thick rubber band against your lip--suddenly stretch it. The lip easily perceives the greater heat. After a few moments let it contract. The greater coldness is equally perceptible.

A wire suspending thirty-nine pounds being twisted ninety-five full turns lengthened itself one sixteen-hundredth of its length. Being further twisted by twenty-five turns it shortened itself one fourth of its previous elongation. During the twisting some sections took far more torsion than others. A steel wire supporting thirty-nine pounds was twisted one hundred and twenty times and then allowed to untwist at will. It let out only thirty-eight turns and retained eighty-two in the new permanent relation of particles. A wire has been known to accommodate itself to nearly fourteen hundred twists, and still the atoms did not let go of each other. They slid about on each other as freely as the atoms of water, but they still held on. It is easier to conceive of these atoms sliding about, making the wire thinner and longer, when we consider that it is the opinion of our best physicists that molecules made of atoms are never still. Masses of matter may be still, but not the constituent elements. They are always in intensest activity, like a mass of bees--those inside coming out, outside ones going in--but the mass remains the same.

The atoms of water behave extraordinarily. I know of a boiler and pipes for heating a house. When the fire was applied and the temperature was changed from that of the street to two hundred degrees, it was easy to see that there was a whole barrel more of it than when it was let into the boiler. It had been swollen by the heat, but it was nothing but water.

Mobile, flexible, and yielding as water seems to be, it has an obstinacy quite remarkable. It was for a long time supposed to be absolutely incompressible. It is nearly so. A pressure that would reduce air to one hundredth of its bulk would not discernibly affect water. Put a ton weight on a cubic inch of water; it does not flinch nor perceptibly shrink, yet the atoms of water do not fill the space they occupy. They object to being crowded. They make no objection to having other matter come in and possess the space unoccupied by them.

Air so much enjoys its free, agile state, leaping over hills and plains, kissing a thousand flowers, that it greatly objects to being condensed to a liquid. First we must take away all the heat. Two hundred and ten degrees of heat changes water to steam filling 1,728 times as much space. No amount of pressure will condense steam to water unless the heat is removed. So take heat away from air till it is more than two hundred degrees below zero, and then a pressure of about two hundred atmospheres (14.7 pounds each) changes common air to fluid. It fights desperately against condensation, growing hot with the effort, and it maintains its resilience for years at any point of pressure short of the final surrender that gives up to become liquid.

Perhaps sometime we shall have the pure air of the mountains or the sea condensed to fluid and sold by the quart to the dwellers in the city, to be expanded into air once more.

The marvel is not greater that gas is able to sustain itself under the awful pressure with its particles in extreme dispersion, than that what we call solids should have their molecules in a mazy dance and yet keep their strength.

Since this world, in power, fineness, finish, beauty, and adaptations, not only surpasses our accomplishment, but also is past our finding out to its perfection, it must have been made by One stronger, finer, and wiser than we are.

MOBILITY OF SEEMING SOLIDS

When a human breath, or the white jet of a steam whistle, or the black cough of a locomotive smokestack is projected into the air it is easy to see that the air is mobile. Its particles easily roll over one another in voluminously infolding wreaths. The same is seen in water. The crest of a wave falls over a portion of air, imprisoning it for a moment, and the mingled air and water of different densities prevent the light of the sun or sky from going straight down into the black depths and being lost, but by being reflected and turned back it shows like beautiful white lace, constantly created and dissolved with a thousandfold more beauty than any that ever came from human hands. All the three shifting elements of the swift creations are mobile. This seems to be the case because these elements are not solid. The particles have plenty of room to play about each other, to execute mazy dances and minuets with vastly more space than substance.

Extend the thought a little. Things that seem to us most solid are