Page:All the Year Round - Series 2 - Volume 1.djvu/69

 which there abounded was exceedingly rich in oil. Mr. Young becoming apprised of the fact, lost no time in acquiring a lease of the coal-field; and in the year following he opened the Bathgate Paraffine Works, which, in the course of a few years, converted a small weaving village, with a population of three thousand souls, into an industrious hive of upwards of ten thousand.

For the sake of convenience we have described the substance from which the future paraffine was to be made as Linlithgowshire "coal;" but this designation has been denied it by learned and competent authorities. To the unpractised eye, however, it is purely a species of coal, and may be regarded essentially as such. It is a hard, lustreless, rusty, black-coloured mineral, very brittle, and apt to break into thin slabs like slates. Perhaps there are few more notable instances of the truth, that you can get men to swear that black is white, and white black, than in connexion with the "coal" to which we are referring. As has been said, it was the subject of a celebrated law-suit. The proprietor to whom the coal-field belonged, becoming aware in due course that an invaluable article called paraffine was being distilled from it, which was rapidly pouring a fortune into the treasury of the distiller, demanded a very large increase of rental. This was refused, and the dispute went to court. The case dragged its slow length for years. Geologists, naturalists, mineralogists, chemists, colliers; witnesses, learned and unlearned, were ranged on either side and pitted against each other. The proprietor of the estate and his friends declared that the substance out of which paraffine was being manufactured was not "coal," as defined in the lease, but a mineral of a distinct species, and that therefore he had the right to increase the rental (seeing the mineral had turned out so valuable), or to get the lease cancelled. Mr. Young and his witnesses, on the other hand, averred that the substance was coal, and none other than coal; and that if he had discovered valuable properties in it he should reap the benefit. The dispute, as is generally the case, was ultimately found to have benefited no one but the lawyers.

Leaving history, let us pass to the process of manufacture. Here the most wonderful part of the tale has to be related. Few persons who are accustomed to use the pure white candles, delicate as wax in their hue, and known popularly by the name of "composites;" and the clear oil, almost as transparent as water, which id called "paraffine;" have any idea that both are produced from a dull, compact coal, totally devoid of the lustre which gives to that mineral the appellation of the "black diamond." And yet this seeming miracle is achieved by the aid of chemistry—that strange science which changes and transmutes substances, and reveals properties hidden and mysterious at the will or instigation of the student. The process by which the change is effected is complicated and laborious; but, freed from its technicalities, it may be easily explained.

The coal yields four different articles, all of which are largely employed in daily life, and have given rise to a considerable commerce. There is, first, the paraffine oil for burning, at present manufactured by thousands of gallons which, in many parts of England, where gas is still unknown, is the staple commodity of illumination. Then a second quality of the same oil, considerably cruder and coarser, which, on account of its cheapness and general aptitude, is largely employed for lubricating machinery. Naphtha comes next upon the list—a light, volatile fluid; much used by travelling showmen to light up their stalls and tents. Lastly, there is solid paraffine—a pure, white, shining, tasteless substance, scarcely distinguishable from wax, which is manufactured into candles. These substances, though widely differing in colour, properties, and consistency, are all manufactured by nearly the same process, the difference consisting merely in the number of times that a particular operation is repeated.

Boghead mineral is the name of the coal employed in the manufacture of paraffine; and this is conveyed from the pits direct into the heart of the works, by means of branch lines of railway. Arrived here, the coal is passed through a huge iron crushing-machine, and broken into small pieces, to facilitate the labour of subsequent stages. The first result to be achieved is to extract the crude oil from the coal. This is effected by means of retorts, into which the mineral is put, and the oleaginous matter extracted by burning. These retorts may, for our purposes, be described as huge upright iron pipes passing through furnaces. The coal is filled into the pipe or tube by the top, which is then closed with an air-tight valve; and the bottom of the pipe is led into a pool of water to prevent the entrance of air from below. A low red heat of uniform temperature is maintained constantly in the retorts. As the coal is acted upon by the fire, it descends gradually in the tube and becomes entirely decomposed. The essential or oleaginous property of the mineral passes off in vapour, and the refuse falls through the bottom of the pipe into the pool of water, and is raked away. The vapour or steam, as it is generated by the decomposition of the coal, is carried off by a pipe in the side of the retort. This pipe again communicates with a series of pipes placed upright in the open air, and arranged on the same principle as the bars of a common gridiron, after the fashion that prevails in gasworks. The vapour, in travelling through this labyrinth of pipes, cools, is condensed into liquid, and is run off into an immense reservoir sunk into the ground. The crude, oily liquor thus collected is a thick, black, greasy fluid, not unlike tar, which moves with a sluggish motion when stirred, and gives off inflammable vapours at the usual atmospheric temperature. This coarse oil, both in its properties and appearance, closely resembles natural petroleum, and is equal to the rock oil, which, is we have seen, was obtained in Derbyshire.

The raw material thus procured by simple burning is kept stored in the tank, and is only drawn off when required. To the observer