Vietnam or Thailand ? Vote for the TOP Country of the Week !
Updated: June 21, 2025
N.B. Do not use clay for your hearth bed unless you can get a highly aluminous clay, and can give it full time to dry before the forge fire is lit. Ordinary surface soil, not too sandy, acts well, if damped and rammed thoroughly. Of course, if you can get an iron nozzle for your blower the whole operation is simplified. Dig a pit 5 feet square by 3 feet deep and fill with fuel.
The gypseous beds are very remarkable, from abounding with, so as sometimes to be almost composed of, irregular concretions, from the size of an egg to that of a man's head, of very hard, compact, heavy gypsum, in the form of anhydrite. This gypsum contains some foreign particles of stone; it is stained, judging from its action with borax, with iron, and it exhales a strong aluminous odour.
Emerging from the valley, we urged on our animals over comparatively level ground, in the fallacious hope of seeing the sea that night. The trees became rarer as we advanced and the surface metallic. In spots the path led over ironstone that resembled slag. In other places the soil was ochre-coloured : the cattle lick it, probably on account of the aluminous matter with which it is mixed.
Also, when fossil wood has been condensed by compression and changed by the operation of heat, as it is frequently found in argillaceous strata, particularly in the aluminous rock upon the coast of Yorkshire, it becomes a jet almost undistinguishable from some species of fossil coal.
This sloping plain or talus blends into a perfectly flat space a few miles in width, composed of reddish impure clay, with small calcareous concretions as in the Pampean deposit, of fine white sand with small pebbles in layers, and of the above-mentioned white aluminous earth, all interstratified together.
We have also, in this country, strata which differ from those aluminous schisti only in the nature of the earth, with which the bituminous sediment is mixed. In the strata now considered, the earth, precipitated with the bituminous matter, being calcareous, has produced a limestone, which, after burning especially, is perfectly fissile.
In others, again, are found considerable quantities of soft powdery iron oxide or "gossan," and compounds such as limonite, aluminous clay, etc., which, under the action of the crushing mill become finely divided and float off in water as "slimes," carrying with them atoms of gold, often microscopically small.
Thus it is an exception to the general rule to meet with a limestone as pure as ordinary white chalk, or with clay as aluminous as that used in Cornwall for porcelain, or with sand so entirely composed of siliceous grains as the white sand of Alum Bay, in the Isle of Wight, employed in the manufacture of glass, or sandstone so pure as the grit of Fontainebleau, used for pavement in France.
Clay is now to be considered as the last of those materials of which our strata are composed; but, in order to understand the nature of this ingredient, something must be premised. Clay is a mixture of different earths or hard substances, in an impalpable state. Those substances are chiefly the siliceous and aluminous earths.
The rearrangement of the mineral constituents by heat goes on here just as in trap, cavities filled with crystals being formed in rocks exposed to great heat and pressure. Where mica abounds, it becomes black and metallic; and the aluminous matter is crystallised in the form of garnets.
Word Of The Day
Others Looking