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306 'Slipp adds much to the weight, and giveth a deeper Black than Copperas itself; which is a good excuse for the Dyers that use it.

'I have hitherto but mentioned the several Colorations used in Humane Affairs, enumerated the several Materials used in one of them, namely, Dying; and imperfectly described the several uses and applications of them in Dying. I have also set down some general Observations relating to that whole Trade. It remains now that we describe the several Vessels, Tools, and Utensils used in the same: And particularly to shew how any Colour assigned may be superinduced upon any kind of Material, as Wool, Linnen, Hair, Feathers, Cotton or Silk: And with what Advantages or Disadvantages of Lasting, Brightness, Cheapness, and Variety, &c. each may be performed. But this being infinite, and almost unteachable by words, as being incomparably more difficult, than how to imitate and compose any Colour assigned, out of the few, usually furnishing a Painter's Palat; I leave the whole to the further consideration of this Learned Society.