Mineral Productions of Shropshire. 3 L I 



secret: a patent was obtained for the discovery by the late 

 Mr. Betton ; but his right to a patent was disallowed, by 

 the decision of a conrt of law, some time after. The oil 

 was used only medicinally, and has probably many of the 

 properties of what is called Friar's balsam, and in quality and 

 appearance has a near resemblance to oil of amber, and is 

 often sold as such. When the manufacture was carried on 

 in its greatest extent, I have understood that a considerable 

 quantity of the oil was exported, and principally to Ger- 

 many. It is still to be bought in Shrewsbury, from the 

 preparer. It is also from a rock of red sandstone that the 

 fossil tar spring, near Coalbrook Dale, issues. Mr. Aikin 

 relates in his book, before quoted, p. 194, that this " spring 

 was cut into by driving a level in search of coal ; that the 

 quantity that issued at first was to the amount of three or 

 four barrels per day ; but that, at present (1797), there sel- 

 dom flowed more than half a barrel in the same period." 

 And in 1 799 Dr. Townson states the produce at only 30 

 gallons per week (now, 1802, it is about half that quantity), 

 though, he imagines, other fissures, filled with the saine 

 substance, may be found, if there were a greater demand for 

 it. The oil distilled from this tar exactly resembles Betton 's 

 British oil, and is used as a solvent for caotdchoucy (com- 

 monly known by the name of elastic gum, or Indian rubber.) 

 which is now used as a varnish for cloth, and is particu- 

 larly applicable to balloons. Near Jackfield, on the south 

 side the river Severn, is carried on the manufacture of coal 

 tar, for which lord Dundonald formerly obtained a patent. 

 In coaking the coal, which is here done in close vessels, 

 they obtain tlie volatile products which are raised m vapour 

 by the heat of the operation of coaking, and condensed in 

 a chamber covered with lead plates, over which water is 

 constantly running. These products are a water and an 

 oil; the former of which contains a portion of volatile al- 

 kali, and the latter is boiled down to t]\e consistence of tar 

 or pitch. The oil which is caught during the boiling down 

 is used as a solvent for resin, and forms an excellent varnish 

 for ships, or any wood-work exposed to weather. Tlic 

 MS. account of Bradford North mentions a salt spring at 

 Smeithmore, in the lordship of Longford ; and Dr. Town- 

 son states several springs of salt water to have been found 

 ill the neighbourhood of the tar spring; and that in the 

 parish of Broscley, on the opposite side of the Severn, salt 

 IS said to have been made formerly from water taken out 

 of pits still called the Salt-house Pits. At the Lyth, in the 

 parish of Cundovcr, is a field the soil of which is impreg- 

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