The elements of materia medica and therapeutics . Oxygen = 16 J Acetic Acid ,2 eq. Oxygen = 16 J Acetic Acid 60 78 78 78 The student will observe that the theory of acetification abovegiven does not account for the evolution of carbonic acid during theprocess, and which is generally considered to be accidental, and notessential to the formation of acetic acid, 2. By tlie Destructive Distillation of Wood.—By the destructive dis-tillation of the hard woods (oak, beech, hornbeam, ash, and birch),in iron cylinders, an impure acid, called Pyroligneous Acid, is ob-tained. The woods should be dried d
The elements of materia medica and therapeutics . Oxygen = 16 J Acetic Acid ,2 eq. Oxygen = 16 J Acetic Acid 60 78 78 78 The student will observe that the theory of acetification abovegiven does not account for the evolution of carbonic acid during theprocess, and which is generally considered to be accidental, and notessential to the formation of acetic acid, 2. By tlie Destructive Distillation of Wood.—By the destructive dis-tillation of the hard woods (oak, beech, hornbeam, ash, and birch),in iron cylinders, an impure acid, called Pyroligneous Acid, is ob-tained. The woods should be dried during several months. Thelighter woods, as fir, and old ship timber, do not pay to distil, as theacid product is too weak. Sometimes the still is a cast-iron cylinder, placed horizontally ina furnace, the fire of which plays around the cylinder, as in fig. 64. r,l ^°^ ^^^f^ ^^^^^^^ consult Ures Dictionary of Arts, pp. 4 and 617; Mitscherlich, Lehrbiich derm%^ed ^*^ ^ ?^^ ^^^* ^ ^^^^ ^•^?^??s Elements of Chemistry, ACETIC ACIB. 393. Section of aFyroligneous Acid Still. Fig. 64. Another form of still is used at a large manu- factory in the neighbourhood of London. Itis a short cylinder of large diameter, placedupright in the furnace. The wood, cut upinto convenient lengths, is introduced intowrought-iron canisters, in each of which is ahole, to allow of the escape of volatile the aid of a crane, these canisters areraised and deposited in the cylindrical still,the top of Avhich is then carefully closed andmade air-tight by luting. The still com-municates with a large iron pipe whichpasses successively through two tanks of coldwater, in which it is variously convoluted,and terminates in an underground reservoir,where tar and an acid liquor are incondensible products are carbonic acid and some inflammablegases (carbonic oxide, light carburetted hydrogen, and olefiant gas),which escape. When no more volatile matter comes over, the stillis opened, and the
Size: 1382px × 1808px
Photo credit: © The Reading Room / Alamy / Afripics
License: Licensed
Model Released: No
Keywords: ., bookcentury1800, bookdecade1840, booksu, booksubjectmateriamedica
