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ink will be made more durable, the Indian ink in somemeasure covering it, and defending it from the action ofthe air. In all cases, where Indian ink or other similarcompositions are employed, cotton should be used in theink-stand, as already mentioned, to prevent the settling ofthe black powder.

Though the foregoing enquiries have not attained tothe perfection which might be desired, I flatter myself thatthey will not be found unimportant; that even the unsuc-cessful experiments, if they contribute nothing in a philo-sophic view, will at least have this use, that they will lesienthe labour to others who may engage in the same pursuit;that a composition of ink has been given, of as black anddurable a colour, as there are grounds to believe the ma-terials to be capable of producing; that an improvementhas been proposed in the manufacture of paper, by whichthe duration of inks will be greatly prolonged; and thatmeans have been pointed out of obtaining, for purposeswhere such duration is required, writings as lasting as thepaper itself, with fewer inconveniences, than those, whichfor all occasions of writing, men acquiesced in for ageswithout complaint.

SECT. VII.

Of the dying of woollen black.

I. General observations on the black dye.

T HE ingredients from which common writing inkis prepared, green vitriol and astringent vegetables,make the basis of the black dye; the dying of cloth blackbeing no other than the producing of an ink in its pores,,or impregnating it with the colouring parts of ink alreadymade.. There are, however, some variations in the com-position