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into the paper, on account of its not being fully disen-gaged from the acid, or sufficiently combined with theastringent matter of the galls.

Hence it should seem probable, that if the paper wasimpregnated with astringent matter, the colour of theink would be more durable ; and that therefore a practicesimilar to that of the dyer, would be a valuable additionto the business of the paper-maker.

To fee how far this notion was well founded, I diptsome paper in an infusion of galls, and when dry, repeatedthe dipping a second and a third time. On the paperthus prepared, and on some of the same paper unprepared,I wrote with different inks; several of which, that theeffect might be more sensible, had an over proportion ofvitriol. The writings being exposed to the weather,till the best of the inks on the unprepared paper hadfaded and changed their colour, those on the preparedpaper were all found to retain their blackness.

It is therefore recommended to the consideration of thepaper-makers, whether a particular kind of paper mightnot be prepared for those uses where the long durationof the writing is of principal importance, by impregnatingit with galls, or other astringents, in some of the opera-tions which it pastes through before it receives the glaz-ing ; as for instance, by using an astringent infusion,instead of common water, in the last operation, when thematter is reduced into a pulp for being formed intosheets. The brownish hue, which the paper receivesfrom the galling, would not perhaps be any great obstacleto its use; and if the proposal should be thought worthyof being carried into execution, further enquiries maypossibly discover means of obviating the imperfection,and communicating astringency without colour.

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