Weights and Measures. 3

As a pound weight of fcarcely any liquorfills the meafure which we call a pint, we haveevery where prefixecl P. or M. as each fub-ftance is prefcribed by weight or meafure*

We deem mortars, made of brafs, or cop-per, improper for preparing medianes.-f-

Alfo meafures, funnels, and veffels ufedfor the evaporation of liquids, which are madeof copper, lead, or a mixed metal of which

B 2 fome

* The precaution above-mentioned, though highly necef-fary in the original Latin of the Pharmacopoeia, is not fogenerally required in an Englifh tranflation. In Englifh, theWord Pint diftinguifhes the Libra by meafure from that byweight, without ambiguity. With regard to the ounce andits divifions, the words by weight or by meafure will, in thisTranflation, beconitantly inferted.

t The propriety of this and the following injuncYion needslittle proof.—It is certain, that even the fofter abforbent fub-ffances, rubbed for a fhort time in a bell-metal mortar, ufu-ally fuppofed not liable to abrafion, acquire in fome degree acupreous quality; as appears on the affufion of volatile alka-li.—As to veffels of lead and its Compounds, the danger at-tending their ufe is univerfally known and acknowledged.—See Mr. Blizard's Effay on bell-metal mortars and pew-ter veffels, 8vo, 1786.