3H
1000 tons of alum, which are sold at from 20/. to 25/. per ton.I'art of the alum is sent to England, Ireland, America , and theWest Indies , and the rest is consumed at home.
This salt, so applicable in many chemical purposes, is used togreat extent in the leather, dying, and calico-printing manu-factures ; in candle and paper making ; and for other useful pur-poses.
7. Sulphat of Iron, Green Vitriol, or Copperas .—There are fourcopperas works in Scotland —two at Hurlet, one at Campsie, andthe other at Baldernock in Stirlingshire, which employ 20 men,and manufacture upwards of 1000 tons annually. The price ofcopperas is at present from 5l. to 5/. 10s. per ton. This substanceis very generally used in the arts ; but the chief consumption isby dyers, calico-printers, and curriers, for imparting black anddark colours.
8. Cudbear, named from Cuthbcrt, the person who began thismanufacture in Glasgow , is still, so far, an extensive monopoly,no other being in Scotland . There is one in Liverpool; anotherwas in London, but is given up ; and it was attempted in Ireland ,without success. Having been 40 or 50 years in existence here,it may excite surprise that the secret of making this article shouldhave remained so long undivulged.
It is a dye-stuff used in different ways for vegetable, but prin-cipally for the animal substances, wool and silk. To these itcommunicates very permanent purple, lilac, and various othershades, in which the red and blue colours are combined.
The chief, probably the only, materials used in its manufac-ture, are human urine and archil, a species of moss or lichen,collected in the Highlands of Scotland, and Norway ; and latter-ly from several of the Canary Islands, and Malta .
By distillation, the ammonia of this fluid is driven off, andwhen united with water, forms liquid ammonia, which is usedfor sprinkling the moss in the process of converting it into Cud-bear.
The buildings and machinery, principally pumping apparatus,are pretty extensive. A dozen or two of hands are employedperforming various parts of the operations, of the nature ofwhich, they are doubtless in a great measure ignorant. Others,with a few horses, collect the urine about the suburbs, and thecollectors are furnished with pocket hydrometers, to preventtheir being imposed upon by a spurious or inferior article. Largequantities of cudbear are sent to the West of England, and tothe European and American Continents.
9. Cream of Tartar is refined at the above work, and at Itu-therglen Bridge, near Glasgow . This is used in dying and me-dicine. It is imported in a crude state. At the Cudbear work,Rochelle Salts are likewise prepared.