Simple Or Single

Distil 2 lb. of saltpetre and 1 lb. of copperas.

Double

Saltpetre, 6 lb., copperas, 6 lb. in its usual crystallised state, together with 3 lb. calcined to redness.

Strong

Copperas calcined to whiteness, and white saltpetre, of each 30 lb.; mix, and distil in an iron pot with an earthenware head.

Spirit Of Nitre

White saltpetre, 6 lb.; oil of vitriol, 1 1/2 lb.; distil into 1 1/2 pint of water.

Dilute

Strong aquafortis, 1 oz. by measure, and water 9 oz. by measure.

Proof

The same as Assayer's Acid.

Compound

Double aquafortis, 16 oz.; common salt, 1 dram: distil to dryness, Aqua-regia.

(a) Distil together 16 oz. of spirit of nitre, with 4 oz. of common salt.

(6) Equad parts of nitric acid and muriatic acid mixed.

(c) Nitric acid 2 parts, and muriatic 1 part.