1865.] Deafer on Petroleum. 57 



investigated by Beichenbach, and many new products among the 

 parafline discovered. Christison, in England, also discovered parafline 

 about the same time. Afterwards the matter attracted great attention 

 in France, and in the patents taken out by Selligue and others in that 

 country, from 1834 to 1845, full details of apparatus, which has not 

 been essentially improved up to the present day, are to be found. In 

 the patent of March 19th, 1845, Selligue enumerates the products of 

 distillation as, — l,a limpid whitish volatile oil, useful as a solvent, and 

 sometimes called naphtha ; 2, a straw-coloured oil suitable for burning 

 in lamps with a double ciuTent of air ; 3, a heavier oil for lubricating ; 

 4, a red colouring matter ; 5, parafline ; 6, a grease composed of 

 parafline and oil ; 7, a black pitch ; 8, an alkaline soap ; 9, sulphate 

 of ammonia ; 10, ammoniacal fertilizing liquors ; 11, sulphate of aliunina. 

 His plan was to treat the crude coal oil obtained from the retorts in 

 which the bituminous substance was distilled with a strong mineral 

 acid, and agitate it thoroughly. This caused the tarry matters to 

 subside with the acid. The slight proportion of acid remaining with 

 the oil was neutralized by an alkali, which caused another precipitate 

 of tar and colouring matter. The oils were then separated from one 

 another by fractional distillation. 



In England, and also in America, the introduction of coal-oil dis- 

 tillation is due to James Young of Glasgow, whose attention was 

 attracted to the subject by the exudation of Petroleum from a coal 

 mine in Derbyshire. He subsequently found that the Boghead Canal 

 was the most suitable mineral for the manufacture of coal oil, and in 

 1854 extracted at the rate of eight thousand gallons a-week, or 10O,00OZ. 

 worth per annum. From England the manufacture extended to the 

 United States, Young having patented his process in both countries, 

 the intention being to use the Boghead Canal of Nova Scotia, or some 

 similar material from the West. The best specimens of the Boghead 

 Canal were found capable of yielding a hundred and thirty gallons of 

 crude oil, or seventy-five gallons of refined oil per ton. Many varieties 

 of coal found in Kentucky and Ohio would produce nearly as great an 

 amount. In 1860 the total number of manufactories in the United 

 States was more than sixty. Of course the discovery of the Petroleum 

 deposits has entirely destroyed this branch of industry. Nature can 

 distil more cheaply than man. 



The success of coal distillation turns on using a temperature not 

 high enough to produce gaseous matters, and yet sufficiently high to 

 drive the oil over. For this reason the best French retorts were 

 cylinders which were caused to revolve slowly over the fire. The 

 volatile matters make their exit through one of the axles upon which 

 the cylinder revolves. The temperature needed is less than a red heat. 

 Two and a half tons of coal, which is the amount that can be employed 

 at a time in a retort eight feet long and six feet in diameter, may be 

 distilled in six horns. The apparatus is liable to the objection that 

 much of the content is reduced to dust, which escapes with the vapours 

 and demands additional means of purification. The vapours are con- 

 densed in iron cylinders, where the water and oil are separated, and 

 the gases escape either into the chimney, or are led into the fire under 

 the retort. 



