Chapter LV, of Cassells Illustrated History of England, Volume 9

It is not simply as fuel that coal is valuable to man. Many useful and beautiful products have in recent times been extracted from it, principally by reason of the rapid advance of chemical science.

In the year 1847 Dr. Lyon Playfair had his attention drawn to a thick, dark oily fluid trickling from the roof of a colliery at Alfreton in Derbyshire. He suggested to Mr. James Young to examine the liquid with a view to ascertain its chemical qualities. An investigation was accordingly made, and it was found to contain, among other substances, the oil called paraffin. For two years afterwards the crude liquid was distilled and its products utilised, but after that time the supply failed. Mr. Young came to the conclusion, after some subsequent experiments, that the Alfreton petroleum was the result of coal being distilled by subterranean heat, and he found by distilling coal he could obtain a liquid of similar qualities. The best coal for this purpose he round was cannel coal. " Some bituminous coal obtained from Boghead, near Bathgate, in the county of Linlithgow," says Mr. Bremner, " was tried by Mr. Young in 1850, and found to be peculiarly rich in oil. As the supply was abundant, Mr. Young, after taking out a patent for 'treating bituminous coal to obtain paraffin and oil containing paraffin,' was joined by Messrs. Meldrum and Binney; they selected a site near the town of Bathgate, and erected thereon an extensive establishment for extracting oil from coal and converting it into a variety of useful products. Such was the beginning of a branch of trade which speedily assumed great importance, and converted the quiet town of Bathgate, together with the adjacent villages, into a great centre of industrial activity. A proof of the remarkable success that attended Mr. Young's enterprise, and the deep hold that it took on the district, is afforded by the fact that though the population of the parish and town of Bathgate had increased only from 2,513 to 3,341 between the years 1801 and 1851, the ten succeeding years witnessed an increase to 10,000. The manufactory was extended until it covered a great space of ground, and the value of its products was recognised throughout the world."

The crude oil obtained from the distillation of the coal is subjected to several subsequent processes, under which it yields four different products - namely, paraffin oil for burning, paraffin oil for lubricating machinery, a light volatile fluid called naphtha, and solid paraffin.

The first product taken off is naphtha, for the separation of which only a gentle heat is required. Naphtha is a valuable liquid extensively employed in the arts and as an illuminator. By raising the temperature of the stills after the naphtha vapour has passed off, paraffin oil is obtained. Before being ready for market, both the naphtha and the oil are distilled separately in order to make them perfectly pure. The oil is the most valuable and important of all the articles manufactured at Bathgate, and is extensively known for its illuminating qualities. One gallon of paraffin oil is equal in illuminating power to one and a quarter of American petroleum; and it can be produced at a price which gives light cheaper than English coal-gas. When all the finer oil has been distilled over, the heat is increased and a heavier vapour is driven off. This last produces a thick oil, which, when thoroughly cooled, assumes the consistency of grease. It is in reality a mixture of oil and solid paraffin. When the paraffin has been crystallised by cooling the liquid, it is separated from the oil by a process of filtration under pressure. The oil extracted in this way is an excellent fluid for lubricating machinery, and is largely used in cotton mills and other establishments in which machinery of a delicate kind is employed. The solid paraffin left behind after the extraction of this oil is of a dirty yellow colour, and requires to be purified before it assumes the beautiful wax-like appearance by which it is distinguished. It is placed in iron vessels and dissolved by heated naphtha, which carries off part of the impurities. It is then cooled and filtered in canvas bags. The whole process is again repeated until the solid paraffin comes out a perfectly white and pure wax. The odour of naphtha is removed by the action of steam, and the paraffin in a melted state is run into circular iron moulds, in which it solidifies. The tapers or candles made of this beautiful substance are known and admired in all parts of the world. It was some time before Mr. Young invented them that the celebrated chemist, Baron Liebig, said, " It would certainly be esteemed one of the greatest discoveries of the age, if any one could succeed in condensing coal-gas into a white, dry, solid, odourless substance, portable, and capable of being placed in a candlestick." " This very problem," remark the jury of the 1851 Exhibition, " Mr. Young appears to have accomplished by distilling coal at a low temperature; " and at the Exhibition of 1862, Dr. Hofmann, reporting for the jury, describes " Mr. Young as the founder of this industry," and speaks of the specimens exhibited " as realising the great problem which the rare sagacity of Liebig pointed out ten years ago." Mr. Young's patent expired in 1864, and since that time fresh works have been opened. The largest of these is in the parish of West Calder, at Addie- well, which cover no less than seventy acres of ground, fully one-third of this area being covered by buildings, tanks, condensers, &c., while a large portion of the remainder is taken up by railways and roads which give access to all parts of the vast establishment. The paraffin is manufactured from coal shale obtained close to the works. Among the subsidiary products of the manufacture there is a large quantity of gas produced, which is used to light up the works at night. More recently traces of ammonia were discovered, and this is now treated with sulphuric acid, and secured in the form of sulphate of ammonia. Altogether, upwards of 3,000 persons are employed in the mineral oil works of Scotland. The trade recently experienced a period of depression owing to the extensive importation of the low-priced petroleum from North America; but the greater purity of the paraffin produced at home has enabled it to recover its ground, and the trade is again flourishing. In 1872, from 800,000 tons of shale as much as 10,000,000 gallons of paraffin oil were estimated to have been produced, besides 5,000 tons of solid paraffin, and large quantities of naphtha, lubricating oil, gas, and sulphate of ammonia. There are several new uses to which paraffin has recently been applied, as, for instance, as a substitute for brimstone in lucifer matches, as a waterproofing agent for woollen fabrics, as a preservative of beer casks from fouling, and as an antiseptic covering for various articles.

Mr. Young's little factory at Alfreton, it has been remarked, was the parent not only of the Scotch mineral oil trade, but also of that of America. Petroleum is now produced in the United States and Canada in immense quantities; but until Mr. Young had commenced operations, the mineral oils of America could never be distilled so as to make them articles of commerce. The oil trade of Scotland is now worth a million sterling annually, and that of America cannot be estimated at less than from ten to fifteen times that amount.

Half a century before paraffin was first extracted from the coal-measures, coal was employed to produce the ordinary gas for the purpose of illumination; and in the process of dry distillation through which the coal is put in the manufacture of gas, a product was formed, for which little or no use could be found. Of the product in question - common coal-tar - about 3 cwt. is produced from 100 cwt. of coal. Until the year 1856, this gas-tar, which is a mixture of some fifty chemical substances, remained almost valueless. But in that year Mr. W. H. Perkin, of Manchester, accidentally made a discovery, which has raised the very refuse of gas-works into one of the most interesting and wonderful of all the products of chemical industry. He was trying an experiment, in which his object was to produce a certain colourless liquid, instead of which he found that he had obtained a reddish sediment. Further examination and experiment "with the same materials led him to the discovery of one of the most beautiful of colours, to which was given the name of mauve. The attention of scientific and practical chemists was soon turned to the new branch of investigation. Dr. Hofmann, who produced a whole series of colours, varying from a very red purple to nearly pure blue, and known as Hofmann's violets, identified the substance at the foundation of the new colour with a material called crystalline, which had been obtained by Dr. Unverdorben from indigo, and it is from and, the Portuguese name of indigo, that the new colouring material received its name of aniline. In 1859, M. Verguin, of Lyons obtained and commenced the manufacture of another beautiful coal-tar dye, known as magenta, and since that time a multitude of new colours, including aniline green, yellow, orange, black, and brown, have been discovered, and made articles of commerce. Before the production of these materials, various dyes - the secret of whose manufacture was unknown in Europe - were imported from China; but. the importation of Chinese dyes has since then rapidly decreased, and, on the other hand, European manufacturers export aniline dyes to China. Coal-tar contains only from one-third to one-half per cent, of aniline, and the latter is not extracted directly from the tar, but from an intermediate compound, termed nitrobenzol, by help of iron filings and acetic acid, according to a process introduced by Mr. Nicholson. It is estimated that three and a half million pounds of aniline dyes were produced in Europe in 1871. Besides the aniline colours, there are also the naphthalin colours, known as Manchester yellow (jaune d'or), Magdala red, naphthalin violet, and naphthalin blue, which are likewise all derived from coal-tar.

Common salt, of which a considerable quantity is used in the alkali manufacture, is produced principally in Cheshire and Worcestershire, partly in the form of rock salt-, and partly by evaporation from salt springs, which issue from a depth of from thirty to sixty yards beneath the surface of the earth. Up to 1823 there was an enormous duty - ten shillings a bushel - on salt, but since 1825, when the salt-tax was abolished, the production has greatly increased. Salt supplies the Liverpool merchants to some extent with outward cargo, where otherwise ships would have to go out in ballast, and large quantities sent down the Weaver from the Cheshire salt-works are shipped at that port. The total quantity exported from the United Kingdom in 1871 was upwards of 890,000 tons, of which a large quantity went to the United States, the East Indies, and other countries. In 1852 it was estimated that 1,000,000 tons were produced in England, of which 300,000 were used for domestic purposes, 200,000 for manufactures, and the rest exported. In 1858 the production had risen to 1,400,000 tons, and since that date has considerably increased.

It is not in these branches of industry only, however, that the influence of the advancing knowledge of chemistry has been felt; but in many others, and amongst these particularly in that of agriculture. " Perfect agriculture," says Baron Liebig, " is the true foundation of all trade and industry - it is the foundation of the riches of states. But a national system of agriculture cannot be formed without the application of scientific principles; for such a system must be based on an exact acquaintance with the means of nutrition of vegetables, and with the influence of soils and actions of manure upon them. This knowledge we must seek from chemistry, which teaches the mode of investigating the composition, and of studying the characters of the different substances from which plants derive their nourishment." It is, indeed, in a large measure due to the researches of Liebig in animal and vegetable chemistry, and the application he made of the results to agriculture, that the practice of farming has, within the past thirty years, been almost revolutionised. The most successful agriculturists proceed no longer by rule of thumb, but in accordance with scientific principles. The science and art of the proper treatment of soils, of the proper manures for the several kinds of crops, &c., have been rapidly advancing since the great German chemist, at the instance of the British Association for the Advancement of Science, wrote his celebrated treatise on the subject. Since that period, too, the production of artificial manures has been constantly increasing. The manufacture of bone manure, of phosphates, of nitrate of soda, the use of coprolites and other minerals, the importation of guano, bones, phosphorite, are all examples of the activity of this new branch of industry, which in practice owes much of its success to Mr. J. B. Lawes, of Rothampsted, the father of the chemical manure trade. The sewage of towns has also been the subject of numerous experiments, but, though these have been partially successful, the problem of the application of the vast quantities of sewage produced in large towns still remains to be solved.

While chemistry has rendered its powerful aid to agriculture, the latter also owes much in recent times to improved machinery. It is to the use of the steam- plough and various other labour-saving implements, combined with the increasing substitution of pastures and meadows for arable land, that the decrease in the agricultural population, which was pointed out in an earlier chapter, is attributable. The value of agricultural produce, owing to the rapid general growth of population on the limited area of Britain, has, on the other hand, considerably increased. The. introduction of improved machinery has not only led to a reduction in the number of farm-labourers, but to an enlargement of farms, by the amalgamation of two or more small holdings into one. The extent to which this practice of swallowing up small farms in large ones has progressed in recent years may readily be shown. In seventeen of the principal agricultural counties of England the total number of farms fell from 68,635 in 1851 to 59,870 in 1871. The number of farms of 2,000 acres and upwards rose in those counties from 64 in 1851 to 90 in 1871; those of 1,000 acres and upwards rose from 492 in 1851 to 582 in 1871; those of 500 acres and upwards from 2,755 in 1851 to 3,194 in 1871; those of 300 acres and upwards from 7,771 in 1851 to 8,410 in 1871. f But the holdings below 300 acres decreased, those between 200 and 30Q acres from 6,930 in 1851 to 6,251 in 1871; those between 100 and 200 acres from 14,795 in 1851 to 12,047 in 1871; and those below 100 acres from 39,139 in 1851 to 33,162 in 1871. Between the same years the number of agricultural labourers, together with shepherds and indoor farm-servants, also fell from 1,110,311 in 1851 to 922,054 in 1871. This change in the mode of agriculture, and reduction of the number of persons directly engaged in it, is due to the introduction of machinery. In manufactures the employment of labour-saving machinery generally, after no long time, instead of causing a reduction in the number of persons employed, leads to a more or less considerable increase in their numbers. In agriculture, even including the labour expended on the manufacture of agricultural machinery, this has hitherto not been the case. The production of a given amount of food at a smaller expenditure of labour is an undoubted advantage; but the changes hitherto occasioned by the introduction of machinery, tending to the depletion of rural districts and the overcrowding of large towns, have by no means been an unmixed good; and if the views held by scientific agriculturists like Mr. Mechi, under whose system of farming the produce of the soil is multiplied many fold, and the views of economists like Mr. W. T. Thornton, who advocates the principle of small holdings, should prevail, then British agriculture is destined soon to undergo another fundamental revolution, and there might even be seen a migration of labourers from the towns to the rural districts, where they might escape the unwholesome confinement and overcrowding of the one without exposing themselves to the abject poverty and degradation which have too long attached to the other. With this short paragraph we must dismiss the subject of agriculture. To discuss with anything like completeness the varied improvements which have recently been made in the art would require a volume in itself.