&c.
Paper, Rheu′matism. See Papers, Gout, and Resin.
Paper, Safe′ty. Syn. Papier de sureté, Fr. White paper pulp mixed with an equal quantity of pulp tinged with any stain easily affected by chlorine, acids, alkalies, &c., and made into sheets as usual.
Paper, Test. Syn. Charta exploratoria, L. Under this head may be conveniently included all the varieties of prepared paper employed in testing. For this purpose sheets of unsized paper or of good ordinary writing paper (preferably the first), are uniformly wetted with a solution of the salt, or with a cold infusion or decoction of the tinctorial substance in distilled water, and are then hung up to dry in a current of pure air; they are, lastly, cut into pieces of a convenient size, and preserved in closed bottles or jars. For use, a small strip of the prepared paper is either dipped into or moistened with the liquid under examination, or it is moistened with distilled water and then exposed to the fumes. A single drop, or even less, of any liquid may be thus tested.
The following are the principal test papers and their applications:—
Paper, Brazil-wood. From the decoction. Alkalies turn it purple or violet; strong acids, red.
Paper, Buckthorn. From the juice of the berries. Reddened by acids.
Paper, Cherry-juice. As the last.
Paper, Dahlia, Georgina P. From an infusion of the petals of the violet dahlia (Georgina purpurea). Alkalies turn it green; acids red; strong caustic alkalies turn it yellow. Very delicate.
Paper, Elderberry. From the juice of the berries. As the last.