A grain of blue vitriol, dissolved in a gallon of water, will make the whole blue. Such a diffusion could not be without an exceedingly minute division of the particles. Perhaps the most minute division of matter is exemplified in odors. A grain of musk will scent a room for years, and yet have no perceptible loss of weight. But all this time the air is filled with fine particles coming from the musk. The microscope reveals to us many wonderful examples of the minuteness of the particles of matter, both in the vegetable and the animal world. If you press a common puff-ball a dust flies off like smoke. Examined with a microscope, each particle of this dust, which is the seed of the plant, is a perfectly round orange-colored ball. This ball is of course made up of very many particles, arranged in this regular form. Beautiful examples of various arrangements of the minute particles of matter we have in the pollen of different plants, as seen with the microscope. Each particle of the dust which adheres to your fingers as you catch a moth is a scale with fine lines upon it regularly arranged. And if you look through the microscope at the wing of the moth, you will see, where the dust is rubbed off, the attachments by which the scales were held standing up from the surface of the wing, like nail-heads on a roof where the shingles have been torn off. The organization of exceedingly small animals, as revealed by the microscope, furnishes us with wonderful examples of the minute division of matter. A little of the dust of guano, examined through a powerful microscope, is seen to contain multitudes of shells of various shapes. These shells are the remains of animalcules that lived in the water, their destiny seeming to be in part to furnish food to other animals larger than themselves. In the chalk formations of the earth are seen multitudes of such shells. They have been discovered even in the glazing of a visiting-card; for they are so small that the fine grinding up of the chalk does not wholly destroy them. There are animals, both in the air and in the water, so small that it would take millions of them to equal in bulk a gram of sand, and a thousand of them could swim side by side through the eye of a common-sized needle. Now in all these animals there are organs, constructed of particles of matter, which are arranged in them with as much order and symmetry as in the organs of our bodies. How minute then must these particles be!