I

Benzine.........   20 ounces

Oil of lavender... 1 fluidrachm Potassium dichro-

mate.......... 1 ounce

Sulphuric acid. . . 1 fluidounce

Water..........   20 fluidounces

Dissolve the dichromate in the water, add the acid and, when the solution is cold, the benzine. Shake every hour during the day, allow to stand all night, decant the benzine, wash with a pint of water and again decant, then add the oil of lavender.

II

First add to the benzine 1 to 2 per cent of oleic acid, which dissolves. Then about a quarter of 1 per cent of tannin is incorporated by shaking. A sufficient quantity of caustic potassa solution, or milk of lime, to combine with the acids is then well shaken into the mixture, and the whole allowed to stand. The benzine rises to the top of the watery fluid, sufficiently deodorized and decolorized for practical purposes.

III

To 1,750 parts of water add 250 parts of sulphuric acid, and when it has cooled down add 30 parts of potassium permanganate and let dissolve. Add this solution to 4,500 parts of benzine, stir well together, and set aside for 24 hours. Now decant the benzine and to it add a solution of 7.5 parts of potassium permanganate and 15 parts of sodium hydrate in 1,000 parts of water, and agitate the substances well together. Let stand until the benzine separates, then draw off.

IV

Dissolve 3 parts of litharge and 18 parts of sodium hydrate in 40 parts of water. Add this to 200-250 parts of benzine and agitate well together for two minutes, then let settle and draw off the benzine. Rinse the latter by agitating it with plenty of clear water, let settle, draw off the benzine, and, if necessary, repeat the operation.