Sistrum

“ Silica is the gritty part of sand—it is also the basis of all fibrous vegetable matter—a familiar example of this is the ash which shows in packing, which has been burnt by the heat in steam; by a peculiar chemical treatment silica has been made into soluble glass—a liquid. 65 per cent. of the earth’s crust is composed of silica—it is the principal part of rock—pure white sand is silica itself—it is composed of an element called silicum combined with the oxygen of the air. ”

“ These, which have the same affinity with their respective bases as rust has to iron, are silex, lime, barytes, and alumine. Until, however, some further light be thrown upon their nature and constitution, they must continue to hold their former situation of simple earths.
33. Silex, or Siliceous Earth, is the basis of all substances known by the name of quartz and silex (76) . In a state of nature it has never been found pure; but, in combination with other substances, it abounds in almost every country of the globe. ”

“ It would be hard to find any one less informed about such phenomena than myself; but of course I had heard of mineral springs so saturated with silica that the leaves and twigs which fell into them were turned to stone after a time. I dimly comprehended the process, how the silica replaced the vegetable matter, atom by atom, and the result was a duplicate of the object in stone. ”

“ To contain this enormous quantity of fluid, Nature has formed large cisterns within him, from which, once filled, he draws at pleasure the quantity he wants, and pours it into his stomach with the same effect as if he then drew it from a spring, and with this he travels, patiently and vigorously, all day long, carrying a prodigious load upon him, through countries infected with poisonous winds, and glowing with parching and never-cooling sands. ”

“ Hydrogen, which forms two-thirds of water, and enters into some mineral substances, is perhaps next. Nitrogen, of which the atmosphere is four-fifths composed, must be considered as an abundant substance. The metal silicium, which unites with oxygen in nearly equal parts to form silica, the basis of nearly a half of the rocks in the earth’s crust, is, of course, an important ingredient. Aluminium, the metallic basis of alumin, a large material in many rocks, is another abundant elementary substance. ”

“ Silica, or silicium combined with oxygen, is found abundantly in perhaps every igneous rock, and very commonly Is combined in definite atomic proportions with lime, alumina, &c., so as to form a peculiar class of compounds, called silicates, bi silicates, and trisilicates, according to the atomic proportion of silica in the mineral. ”

“ Silex, or SILICA, abounds in flint, sand, sandstone, agate, jasper, &c.; it forms the basis of many precious stones, and particularly of those which strike fire with steel. It is rough to the touch, scratches and wears away metals; it is acted upon by no acid but the fluoric, and is not soluble in water by any known process; but nature certainly dissolves it by means with which we are unacquainted, and thus produces a variety of siliceous crystals, and amongst these rock crystal, 52 which is the purest specimen of this earth. ”

“ It constitutes the principal portion of most of the hard stones and minerals which compose the crust of the globe; occurring nearly pure in rock crystal, quartz, agate, calcedony, flint, &c. Silica or silicic acid may be obtained perfectly pure, and also in the finest state of comminution, by taking the precipitate formed by passing silicated fluoric gas through water, filtering, washing, and igniting it, to expel the last traces of the fluoride of silicon. ”

“ Wall paper containing arsenic is said to be injurious to some people, while apparently harmless to others.
Chapter XLI. SILICON, SILICA, AND SILICATES. 214. Comparison of Si and C.—The element Si resembles carbon in valence and in allotropic forms. It occurs in three forms like C, a diamond form, a graphite, and an amorphous. C forms the basis of the vegetable and animal world; Si, of the mineral. Most soils and rocks, except limestone, are mainly compounds of O, Si, and metals. While O is estimated to make up nearly one- half of the known crust of the earth, Si constitutes fully a third. ”

“ Silica is composed of 21.3 parts of silicon with 24 of oxygen, it is that earth which constitutes a great part of almost every soil, and forms sand, sandstone, and flint, it enters largely also into the formation of granite and the other primitive rocks ”

“ The silica is deposited in the skeleton of a sponge or a radiolaria, the shell of a foraminifera or the carapace of a crustacean, or unites with phosphorus to form the bones of a vertebrate. A very tumult of life has succeeded to the primitive silence of inert matter. ”

“ Silica, sil′i-ka, n. silicon dioxide, or silicic anhydride, a white or colourless substance, the most abundant solid constituent of our globe, existing both in the crystalline and in the amorphous form, the best examples of the former being rock-crystal, quartz, chalcedony, flint, sandstone, and quartzose sand ”

“ It might surprise you to hear that one of the commonest substances that is found in solution in the waters of many hot springs is silica; for silica is practically sand, and sand does not easily dissolve in water as does sugar. The very hot water, however, which comes from the hot spring, whose temperature below the earth's surface is very much higher than it is when it comes out of the spring, possesses the power of readily dissolving silica from the rocks over which it flows. ”

“ The action of the weather on the rocks is almost entirely chemical. With a very few exceptions, the principal minerals of which rocks are composed, such as feldspar, hornblende, augite, and mica, are silicates, i.e., consist of silicic acid or silica combined with various bases, especially aluminum, magnesium, iron, calcium, potassium, and sodium. ”

“ Etym., silex, which see, A siliceous rock is one mainly composed of silex.
Silicified. Any substance that is petrified or mineralized by siliceous earth.
Silt. The more comminuted sand, clay, and earth, which is transported by running water. It is often accumulated by currents in banks. Thus we speak of the mouth of a river being silted up when its entrance into the sea is impeded by such accumulation of loose materials.
Simple mineral. Individual mineral substances, as distinguished from rocks, which last are usually an aggregation of simple minerals. ”

“ There is nothing can give a better idea of the enormous quantity of oxygen present in the animal, vegetable, and mineral kingdoms, than the statement that it represents one-third of the weight of the whole crust of the globe. Silica, or flint, contains about half its weight of oxygen; lime contains forty per cent.; alumina about thirty-three per cent. In these substances the element oxygen remains inactive and powerless, chained by the strong fetters of chemical affinity to the [Pg 88] silicium of the flint, the calcium of the lime, and the aluminum of the alumina. ”

“ Nevertheless, it has been clearly demonstrated by observation, that silica, where it occurs in certain combinations with other mineral substances, may be dissolved readily enough: for instance, in the decomposition of felspar, and of all rocks in which felspar is an ingredient, silica is carried off in a state of solution.37 And since these rocks are very numerous, and distributed over every part of the earth, we may fairly conclude that a solution of silica exists very abundantly in nature. ”

“ Silica is a mineral substance, commonly known as flint; and it is one of the wonders of the vegetable tribes, that, although flint is so indestructible that the strongest chemical aid is required for its solution, plants possess the power of dissolving and secreting it. Even so delicate a structure as the wheat straw dissolves silica, and every stalk of wheat is covered with a perfect, but inconceivably thin coating of this substance. ”

“ Cisterns—Early Mention of Cisterns—Cisterns of Carthage—Early Methods of Raising Water—Water Carriers—Pool of Siloam—Pool of Solomon—Aqueducts—Carthagenian Aqueduct—Aqueducts of Rome—Aqueducts of Segovia, Spain—Trophies of Marius.
The storage of water in cisterns or reservoirs is by no means a modern practice. ”

“ The explanation given is, that a chemical attraction has taken place between the vegetable or animal remains, strewed abundantly through the waters, and the silicious matter held in solution. The silex in solution gradually incrusts, or incorporates with, the organized substance,—and thus were produced at once the flinty concretions and the wonderful petrifactions contained in them. ”

“ I think that it is quite necessary that the silex should be in a soluble state, as I think that it is not only desirable that all the elements necessary to fertility should be in the soil, but that they should be in such a form that they can be assimilated by the plant. Some of our compounds for producing fertility may perhaps be as absurd as it would be to give muriatic acid to a man troubled with indigestion, because free muriatic acid is found in the stomach of a healthy person. ”

“ Lastly, Sal Nitre is the only growth, generation, and encrease of all Vegetables, Animals, and Minerals, as also their Destruction, and Regeneration, by a perpetual Circulation of the Elements, by which things169 being dissolved, do again return into the same from which they arose: For the Nitre of Vegetables in the bodies of Animals, by the intervening digestions and separations, is generated into a Mineral Salt, which none will deny: and Nitre or Salt of the Earth, is Vegetable, Mineral, and Animal, which cannot be said of any other subject, but the Universal Matter. ”

“ Oxygen, which is present in nearly all substances, including air, water, and most solids, constitutes about one-half of all known matter. Silicon is next in abundance, amounting to more than one-fourth of the solid crust of the earth. ”

“ Wherever the fluids of the living body can penetrate, there also mineral substances can be carried, and this natural injection, effected under great pressure and with the advantage of ample time, can surpass any of the feats of the anatomical manipulator. Fig. 16 represents a microscopic joint of a Crinoid from the Upper Silurian of New Brunswick, injected with the hydrous silicate already referred to, and Fig. 17 shows a microscopic chambered or spiral shell, from a Welsh Silurian limestone, with its cavities filled with a similar substance. ”

“ The highest and most extensive mountain ranges are huge masses of silica, and the deserts of Africa and Asia are vast plains of the same abundant substance. Silica forms the sand and shingle of the sea-shore, and enters into the composition of every soil; it is the chief ingredient of some of our most precious jewels ”

“ At last, the showers of melted silex reached the liquid surface of the nucleus, which the force of gravity and compression must have formed, at an early period of the nebulous globe, of less or greater extent about its centre. From this period the increasing torrents of silica, intermingled with the silicates which were forming at the same time, poured down through the heavy vapors, and filled up the furlongs-deep of granite ocean. ”

“ Saints, martyrs, teachers of the truth, are standing round, drinking or filling their vases, which they present to each other. From the cistern flows a stream, at which a family of poor peasants are drinking with humble, joyful looks; and as the stream divides and flows away through flowery meadows, little sportive children stoop to drink of it, scooping up the water in their tiny hands, or sipping it with their rosy smiling lips. ”

“ The large quantities of silex in solution required for the formation of these plants may probably arise from the disintegration of feldspathic rocks, which are universally distributed. As more than half of their bulk is formed of siliceous earth, they may afford an endless supply of silica to all the great rivers which flow into the ocean. ”

“ From these facts, it would seem that flints are as much an aggregation of silex around some organized nucleus, as septaria are aggregations of clay and carbonate of iron. This is now the generally received 220opinion; and when it is remembered that the organisms must have been deposited when the chalk was in a pulpy state, there can be little difficulty in conceiving how the silex dissolved through the mass would, by chemical affinity, attach itself to the decaying organism. Chalk is composed of carbonate of lime, with traces of clay, silex, and oxide of iron ”

“ Bennett writes of silica as one "of those ingredients which are required for the formation or healthy life" of the plant-tissues. In "How Crops Grow," the evidence is given which forces us to the conclusion that silica is unessential to the growth and perfect development not only of leguminous plants, but of all the various cereals, although the latter, when they grow in the soil, do contain 2.5 per cent., more or less, of this substance in their foliage. ”

“ Igneous rocks are always siliceous. Obsidian is a glassy silicate. A mountain of very pure glass, obsidian, two hundred feet high, has lately been found in the Yellow-stone region. We see how important Si is, in the compounds Si02 and the silicates, as a constituent of the terrestrial crust. Limestone is the only extensive rock from which it is absent. Always combined with O, it is, next to the latter, the most abundant of elements. Silicates of Al, Fe, Ca, K, Na, and Mg are most common, and these metals, in the order given, rank next in abundance. ”