e.—s

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those in use at the present day. Early in the nineteenth century many valuable discoveries were made, such as paraffine from wood-tar by Reichenback, in bituminous shale by Lawrent, and in coal-tar by Dumas; but those products were simply scientific curiosities, and it was reserved for Dr. James Young, of Renfrewshire, to make them marketable products. In 1847, when manager of a chemical work at Liverpool, his attention was directed by Dr. Lyon Playfair to a small stream of oil flowing from the top of a coal-working at Alfreton, in Derbyshire, and from this oil he succeeded in extracting marketable products, such as burning-oil, wax, and lubricating-oil. When the supply of this oil got exhausted he naturally looked for other sources, and, like all true scientific men, he imitated what he thought was nature's method—the action of a gentle heat on coal or shale. While he was still experimenting a highly bituminous coal was discovered in Scotland, known as the Boghead coal (afterwards Torbane-hill mineral), which he found to contain from 120 to 130 gallons of oil per ton. It was to work this shale that he took out his patent, No. 13292, and it was this shale which formed the subject of the famous lawsuit. " The discovery of enormous quantities of petroleum in America so much reduced the marketvalue of the products in Scotland that the history of the oil trade for the last twenty years has been one great struggle against excessive competition from abroad. No sooner was an improvement made, and cost reduced to meet a decline in the selling-price, than another decline had to be faced; and lam quite safe in saying that no other industry in Scotland has fought such a noble battle to save it from extinction. The cost of refining a gallon of crude oil has been reduced from 2-2 d. to 0-7 d., and this includes the refining of the wax, and the yield of sulphate of ammonia has been raised from a few pounds up to from 40 lb. to 60 lb. per ton. " Petroleum is found in different geological periods of time. In the United States and Canada it is generally found stored up in the porous sandstones or limestones of the Devonian or Silurian period. In Egypt, India, and Roumania it is found in the Tertiary strata, and at Baku it is found in the Later Tertiary and. Cretaceous and Jurassic ages. In Galicia it is found in the Lower Eocene and Upper Cretaceous rocks. In Hanover in the Gault beds of the Jurassic and also in the Triassic age. In New Zealand I have examined over half a dozen shales, and they all appear to belong to the Tertiary or Jurassic age. " Shale is now well known to be of either vegetable or animal origin, and sometimes of both. In Scotland some of the shales are almost entirely made up of a small microscopic organism called Entomostraca. Shale-oils are generally composed of carbon and hydrogen, with nitrogen, sulphur, and oxygen in small quantities. Most of the nitrogen which the shale contains is driven off as ammonia and some as organic bases. The oil when refined is a comparatively pure hydrocarbon, and the slower and more gently the shale is cooked the better the oil. The element carbon is only able to take up or combine chemically with four atoms of hydrogen to one of carbon, which forms a type molecule of the paraffine series, and is sometimes called a ' saturated hydrocarbon,' because the number of atoms of hydrogen exist in the fullest proportion in which those two elements can combine. If the retort is overheated the molecule loses hydrogen, and is formed into the olefin series (two atoms of carbon to six of hydrogen), and if still more heat is applied it goes into the benzole series (three of carbon to eight of hydrogen); hence the use of steam to prevent the paraffine molecule from losing its hydrogen. A better method for preserving the paraffine molecule or of building up the lower series to the higher has still to be discovered, and would be one of the best discoveries in the history of the oil trade. " The plant which is being laid down at Orepuki is one of the latest and most improved type, the result of fifty years' research by many workers in Scotland. The retorts are the best known for this particular shale, and, while they will be able to preserve the oil, it is expected they will also give a by-yield of sulphate of ammonia. The shale-field has been tested over a large area and found to be nearly uniform in thickness, and giving a quantity of oil over the average shale in Scotland. The mine-tunnel has been put down over 900 ft. at a declivity of lin 4, and is in the centre of a basin, so that the shale and water will go to the bottom without any great expenditure of power. When the shale comes out of the mine it is put into a breaking-machine, and when broken is raised by elevators and put into the hoppers on top of the retorts. The shale in the retort is kept in continuous motion by machinery at the bottom, and when exhausted runs away at the bottom. By means of a fan the oily vapour is drawn from the retorts through a series of condensers, where the gases are cooled, and the liquid portion (oil and water) runs into a large receiv-ing-tank. The gas is passed on through two large towers, where it is first scrubbed with water, which robs it of its ammonia-gas, and then with oil, which robs it of its spirits. The gas then goes on to the retorts, where it is used for firing. Sulphate of ammonia is extracted from the water which comes over along with the crude oil, and the crude oil is pumped up into a large tank, separated from any water which it may contain, and then run into the still. The still is then heated up, and the oil-vapour passes over and is again condensed and run into a receiver. During the distillation steam is passed through the still to bring over the oil at a lower temperature, and preserve the paraffine molecule. After the distillation is finished there is a coke left in the still, which is used for making moulders, blacking, and for burning in parlour-fires, as it gives a good heat and practically no ash. The oil in the receiver is next treated with sulphuric acid and soda-hydrate and again distilled, and this time cut into light and heavy portions. From the light portion burn-ing-oil is obtained, and from the heavy, lubricating-oils. The light portion is again treated, distilled, and again treated, and is finished burning-oil. The heavy portion goes to the paraffine-shed, where it is frozen and the paraffine-wax extracted. The oily portion is then again treated and distilled, and cut up into the different grades of lubricating-oil. These lubricating-oils are again frozen and more wax extracted, again treated, and are ready for the market. The paraffine-wax is put into a sweating-house, where the temperature is gradually raised. Any oil which it contains comes away first, bringing a lot of impurities with it, then the lower melting-point wax, and lastly the high-melting-point wax, which all run into different receivers. This process has generally to be