Pages 85-168
The workmen are divided into two parties, with an overseer, or tally-man, to see that the assigned number of journeys is duly performed; and as they all run the same distance, whilst one party is out upon the journey, the other is employed each in filling his own barrow, which prevents all interruption and confusion. By thus proportioning the size of the barrows to the strength of the workmen, boys of twelve or fourteen years of age find employment; and when a man, through age or infirmities, finds himself unequal to a barrow of the largest size, he has an opportunity of making choice of a smaller [barrow], his earnings being always in proportion” (Graves, 1808, 336). “As the process of making allum has been fully described in Keir’s Essay on Chemistry, in Ray’s Collection of English words (p.201), in the Philosophical Transactions (No. 842) and other publications, we shall not detain the reader with extracts from these authors, but briefly observe, that the preparation consists in rendering the ore, in the first place [to] aluminous, and afterwards in dissolving and purifying the salt. As most of the allum stone, (which, when dug from the [solid] rock is of the colour of slate,) is found to contain a mixture of clay and sulphur, the latter must be converted to vitriolic acid, before it can form the aluminous combination; which is most expeditiously effected by actual combustion. After the stone, which is thrown into large heaps, has been sufficiently burned, it is put into pits and steeped in water, in order to extract the saline matter, where it remains until the ore is reduced to such a state, as that it may be made into paste with the hand.
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