Cooley's cyclopaedia of practical receipts and collateral information in the arts, manufactures, professions, and trades including medicine, pharmacy, hygiene, and domestic economy : designed as a comprehensive supplement to the Pharmacopoeia and general book of reference for the manufacturer, tradesman, amateur, and heads of families . eb. 25, 1855),in consequence of being severely hiuned whilst experi-menting on benzol. 2 Preferably considerably below. If the distillate benot rich in benzol, a temperature so low as 8 or 10°, oreven 4-5°, Falir. may be necessai-y or, at all events, ad-vantage
Cooley's cyclopaedia of practical receipts and collateral information in the arts, manufactures, professions, and trades including medicine, pharmacy, hygiene, and domestic economy : designed as a comprehensive supplement to the Pharmacopoeia and general book of reference for the manufacturer, tradesman, amateur, and heads of families . eb. 25, 1855),in consequence of being severely hiuned whilst experi-menting on benzol. 2 Preferably considerably below. If the distillate benot rich in benzol, a temperature so low as 8 or 10°, oreven 4-5°, Falir. may be necessai-y or, at all events, ad-vantageous. BENZOL 287 bibulous paper, and then allowed to liquefyby simple exposure, in a close vessel, to theordinary temperature of the atmosphere. Theproduct, after rectification at a temperaturenot exceeding 190,° is nearly pure benzol. Itmay be rendered absolutely pure by repoathigthe refrigeration a second and a third time, fol-lowed by a final rectification at 180-185° Fahr. 2. Commercial :—By submitting light coal-tar naphtha to distillation, either at once, orafter it has been agitated with a little oil ofvitriol, and decanted, care being taken that thetemperature does not exceed 200° Fahr. A drawing and description of the apparatusinvented by Mansfield for the preparation ofbenzol from coal-tar naphtha is given A is the still placed on a furnace R; C is filled with cold water. As soon as the oil in tbestill boils, the vapours arc condensed in B,and flow back into A; tliis continues untiltbe water in C has been heated to a certaintemperature, when the vapours aie condensedin the cooler D, the liquid flowing at n intothe carboy S. As soon as the water in Cbegins to boil, all the substances contained inthe coal-tar naphtha and volatile at 212° condensed and collected in S. A very purebenzol is obtained by this apparatus. Byopening the tap m, the hydrocarbons whichboil over 212° Fahr. can be rectified. Thestopcock i is used for opening the still. In th
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