What myriads has the microscope revealed to us of the rich luxuriance of animal life in the ocean, and conveyed to our astonished senses a consciousness of the universality of life! In the oceanic depths every stratum of water is animated, and swarms with countless hosts of small luminiferous animalcules, mammaria, crustacea, peridinea, and circling nereides, which, when attracted to the surface by peculiar meteorological conditions, convert every wave into a foaming band of flashing light. USE OF THE MICROSCOPE TO MINERALOGISTS. M. Dufour has shown that an imponderable quantity of a substance can be crystallised; and that the crystals so obtained are quite characteristic of the substances, as of sugar, chloride of sodium, arsenic, and mercury. This process may be extremely valuable to the mineralogist and toxicologist when the substance for examination is too small to be submitted to tests. By aid of the microscope, also, shells are measured to the thousandth part of an inch. FINE DOWN OF QUARTZ. Sir David Brewster having broken in two a crystal of quartz of a smoky colour, found both surfaces of the fracture absolutely black; and the blackness appeared at first sight to be owing to a thin film of opaque matter which had insinuated itself into the crevice. This opinion, however, was untenable, as every part of the surface was black, and the two halves of the crystals could not have stuck together had the crevice extended across the whole section. Upon further examination Sir David found that the surface was perfectly transparent by transmitted light, and that the blackness of the surfaces arose from their being entirely composed of _a fine down of quartz_, or of short and slender filaments, whose diameter was so exceedingly small that they were incapable of reflecting a single ray of the strongest light; and they could not exceed the _one third of the millionth part of an inch_. This curious specimen is in the cabinet of her grace the Duchess of Gordon. MICROSCOPIC WRITING. Professor Kelland has shown, in Paris, on a spot no larger than the head of a small pin, by means of powerful microscopes, several specimens of distinct and beautiful writing, one of them containing the whole of the Lord’s Prayer written within this minute compass. In reference to this, two remarkable facts in Layard’s latest work on Nineveh show that the national records of Assyria were written on square bricks, in characters so small as scarcely to be legible without a microscope; in fact, a microscope, as we have just shown, was found in the ruins of Nimroud. HOW TO MAKE A MAGIC MIRROR.