Part 4 (1/2)
The honour of first accooho succeeded in producing very s lareat pressure, in coredients The process was a costly one, and beyond being a great scientific feat, the discovery led to little result
A young French chemist, M Henri Moissau, has since come to the front, and the diamonds which he has produced have stood every test for the true diamond to which they could be subjected; above all, the density of the product is 35, _ie_, that of the dianised that in all diamonds which he had consumed--and he consumed some 150 worth in order to assure himself of the fact--there were always traces of iron in their composition He saw that iron in fusion, like other ht it not be thatin the presence of carbon, deep in volcanic depths where there was little scope for the iron to expand in assu the solid form, would exert such tremendous pressure upon the particles of carbon which it absorbed, that these would assume the crystalline state?
He packed a cylinder of soft iron with the carbon of sugar, and placed the whole in a crucible filled with molten iron, which was raised to a temperature of 3000 by means of an electric furnace The soft cylinder e portion of the carbon The crucible was thrown into water, and a mass of solid iron was formed It was allowed further to cool in the open air, but the expansion which the iron would have undergone on cooling, was checked by the crucible which contained it The result was a tre which the carbon, which was still dissolved, was crystallised into minute diamonds
These showed themselves as minute points which were easily separable from the mass by the action of acids Thus the wonderful transforar to the diamond was accomplished
It should be mentioned that iron, silver, and water, alone possess the peculiar property of expanding when passing from the liquid to the solid state
The diamonds so obtained were of both kinds The particles of white diamond resembled in every respect the true brilliant But there was also an appreciable quantity of the variety known as the ”black diamond”
These diamonds seem to approximate more closely to carbon as we are most familiar with it They are not considered as of such value as the transparent form, but they are still of considerable commercial value
The _carbonado_, as this kind is called, possesses so great a degree of hardness that by h the hardest rocks The dia purposes, is furnished around the outer edge of the cylinder of the ”boring bit,” as it is called, with perhaps a dozen black diaether with another row of Brazilian dia tool the sharp edges of the diarees of hardness, leaving a core of the rock cut through, in the centre of the cylindrical drill It is found that the durability of the natural edge of the diae caused by _artificial_ cutting and tri set with an artificially-cut diaht extent the edge of the stone
The dia a scratch on any substance across which it ed, and whose hardness can be completely destroyed, by the sih lustre, and of its power of breaking up by refraction the light of the sun into the various tints of the solar spectru it into a jar of oxygen gas It ies into a coky mass, and burns away The product left behind is a en, in the proportions in which it is as deprived of its water This is indeed a strange transformation, from the most valuable of all our precious stones to a compound which is the saas which we and all animals exhale But there is this to be said Probably in the far-away days when the diaetable product which was its far-reas from the atmosphere, just as do our plants in the present day By this means it obtained the carbon ith to build up its tissues Thus the combustion of the diamond into carbonic-anhydride now is, after all, only a return to the sainally formed Hoas formed is a secret: probably the time occupied in the formation of the diamond may be counted by centuries, but the time of its re-transformation into a mass of coky matter is but the work of seconds!
There is another forreater ih not a natural product, is yet deserving of some notice here Charcoal is the substance referred to
In early days the word ”coal,” or, as it was also spelt, ”cole,” was applied to any substance which was used as fuel; hence we have a reference in the Bible to a ”fire of coals,” so translated when theto be conveyed was probably not coal as we know it Wood was formerly known as coal, whilst charred wood received the name of charred-coal, which was soon corrupted into charcoal The charcoal-burners of years gone by were a farcommunity than they are now When the old baronial halls and country-seats depended on the was a rate than now, these occupiers of midforest were a people of some importance
We must not overlook the fact that there is another form of charcoal, namely, ani bones to redness in closed iron vessels In the refining of raw sugar the discoloration of the syrup is brought about by filtering it through animal-charcoal; by this means the syrup is rendered colourless
When properly prepared, charcoal exhibits very distinctly the rings of annual grohich may have characterised the wood froht in consequence of its porous nature, and it is wonderfully indestructible
But its greatest, because it is its most useful property, is undoubtedly the pohich it has of absorbing great quantities of gas into itself
It is in fact what may be termed an all-round purifier It is a deodoriser, a disinfectant, and a decoloriser It is an absorbent of bad odours, and partially removes the smell from tainted meat It has been used when offensive manures have been spread over soils, with the same object in view, and its use for the purification of water is well known to all users of filters Soained by the fact that one volume of wood-charcoal will absorb no less than 90 volumes of ammonia, 35 volumes of carbonic anhydride, and 65 volumes of sulphurous anhydride
Other forms of carbon which are well-known are (1) coke, the residue left when coal has been subjected to a great heat in a closed retort, but from which all the bye-products of coal have been allowed to escape; (2) soot and lamp-black, the former of which is useful as apresent in it, whilst the latter is a specially prepared soot, and is used in the manufacture of Indian ink and printers' ink
CHAPTER IV
THE COAL-MINE AND ITS DANGERS
It is soe to think that where once existed the solitudes of an ancient carboniferous forest now is the site of a busy underground town For a town it really is The various roads and passages which are cut through the solid coal as excavation of a coal-er all the intricacies of a well-planned town Nor is the extent of these underground towns a thing to be despised There is an old pit near Newcastle which contains not less than fifty hfares in a direct line are not less than four or five th, and this, it ht by hureat an extent of passages necessarily requires so the air within it in a pure state, such as will render it fit for the workers to breathe The further one would go frohfare in such a mine, the less likely one would be to find air of sufficient purity for the purpose It is as a consequence necessary to take some special steps to provide an efficient systehout the mine This is effectually done by two shafts, called respectively the downcast and the upcast shaft A shaft is in reality a very deep well, and ular or oval in for through the various strata, it is protected by plank or wood tubbing, or the shaft is bricked over, or soreat depth, pass through strata of every degree of looseness or viscosity, all three methods are utilised in turn
In Westphalia, where coal is worked beneath strata of e, narrow shafts have been, inapparatus, in preference to the usual process of excavation, and the practice has since been adopted in South Wales In England the usual forular pits are also in use On the Continent polygonal-shaped shafts are not unco constructed with a view to resist the great pressure exerted by the rock around
[Illustration: FIG 31--Engine-House and Buildings at head of a Coal-Pit]
If there be one of these shafts at one end of the mine, and another at a rein, and a rough kind of ventilation will ensue This is, however, quite insufficient to provide the necessary quantity of air for inhalation by the army of workers in the coal-mine, for the current thus set up does not even provide sufficient force to remove the effete air and i human bodies