Fig. 11. Fig. 12.
62. Crystallization.—The arrangement of the particles of solid substances is different from that of liquids. The tendency here is to straight lines and angles; that is, to crystalline forms. Alum or common salt, when it becomes solid from a solution, forms crystals. So also does sugar. The crystals of different substances are different. In Fig. 11 you have the crystal of common salt, and in Fig. 12 that of alum. We see this crystalline tendency every where, even in the rude rocks and common stones. The rocks are disposed to exhibit regular layers, or columns, or battlements, and always do so except when interfering circumstances prevent. And when you examine their composition, or that of the stone under your feet, you see the same crystalline disposition in detail that you see in the mass.
63. Crystallization of Water.—Water, when it changes into a solid, shows the same disposition, of which the crystals of the snow and the frost-work on our windows are familiar examples. When snow forms, the water of the clouds is suddenly crystallized by the cold air, the particles taking their regular places more readily and certainly than if they were guided by intelligence, because in obedience to an unerring law established by the Creator. We sometimes have an example of this sudden crystallization of water under our eye. The water in a pitcher may remain fluid, although it is cooled down to the freezing point, and even below it, if it be kept perfectly still. But on taking up the pitcher the water at once becomes filled with a net-work of ice-crystals. The explanation is this: The stillness of the water has prevented its particles from taking on the new arrangement needed for the formation of ice; but the jostling of them in taking up the pitcher has served to make them do it thus suddenly.
Fig. 13.
64. Frost and Snow.—The frost-work on our windows is a wonderful exhibition of the variety of forms that crystallization can produce. It sometimes presents figures like leaves and flowers, such as we see chased on vessels of silver, but much more delicate and beautiful. So varied and fantastic are the forms in which these water-crystals are arranged, that it is very natural to ascribe them, as is done universally in the dialect of the nursery, to the ingenuity of a strange and tricksy spirit. Every snow-flake is a bundle of little crystals as regular and beautiful as the crystals which you so much admire in a mineralogical cabinet. And there is great variety in the grouping of these crystals. You have some specimens of these groups in Fig. 13 as they appear on examining them with the microscope. Over six hundred different forms have been enumerated, and a hundred have been delineated. It is a very quick operation by which the particles of water in the clouds thus marshal themselves, as if by magic, in these regular forms. But a quicker operation is that by which hail is formed—so quick that the particles have not time to set themselves in the crystalline arrangement, but are huddled together without order. The brilliant and glistening whiteness of the snow is owing to the reflection of light from its minute crystals. In the arctic regions the beauty of the snow is often much greater than with us. "The snow crystals of last night," says Captain M'Clintock in his "Discovery of the Fate of Sir John Franklin," "were extremely beautiful. The largest kind is an inch in length; its form exactly resembles the end of a pointed feather. Stellar crystals two-tenths of an inch in diameter have also fallen; these have six points, and are the most exquisite things when seen under a microscope. In the sun, or even in moonlight, all these crystals glisten most brilliantly; and as our masts and rigging are abundantly covered with them, the Fox never was so gorgeously arrayed as she now appears."
65. Order in Nature.—We see in this general tendency to crystallization a striking illustration of the fact that God is a God of order. Disorderly arrangement is never seen except where there is an obvious necessity for it. And even when there is apparent disorder, a little examination generally shows that essentially there is order. The rocks that give so much variety to scenery are not piled up in confusion, and order has evidently reigned in their construction. Pick up a common stone, and on breaking it you will see the crystalline arrangement in its interior. Nay, more, much of the very soil is made up of separated and broken crystals.
Fig. 14.