It is doubtful whether at that period, or even much later, any camphor was obtained from Formosa. Du Halde[1898] makes no allusion to it as a production of that island; nor does he mention it among the commodities of Emouy (Amoy), which was the Chinese port then in most active communication with Formosa.
Production—The camphor of European commerce is produced in the island of Formosa and in Japan. We have no evidence that any is manufactured at the present day in China, although very large trees, often from 8 to 9 feet in diameter, are common, for instance in Kiangsi, and camphor wood is an important timber of the Hankow market.
In Formosa, the camphor-producing districts lie in the narrow belt of debateable ground, which separates the border Chinese settlements from the territory still occupied by the aboriginal tribes. The camphor is prepared from the wood, which is cut into small chips from the trees, by means of a gouge with a long handle. In this process there is great waste, many trees being cut and then left with a large portion of valuable timber to perish. The next operation is to expose the wood to the vapour of boiling water, and to collect the camphor which volatilizes with the steam. For this purpose, stills are constructed thus:—a long wooden trough, frequently a hollowed trunk, is fixed over a furnace and protected by a coating of clay. Water is poured into it, and a board perforated with numerous small holes is luted over it. Above these holes the chips are placed and covered with earthen pots. A fire having been lighted in the furnace, the water becomes heated, and the steam passing through the chips, carries with it the camphor, which condenses in minute white crystals in the upper part of the pots. From these it is scraped out every few days, and is then very pure and clean. Four stills, each having ten pots placed in a row over one trough, are generally arranged under one shed. These stills are moved from time to time, according as the gradual exhaustion of timber in the locality renders such transfer desirable. A considerable quantity of camphor is however manufactured in the towns, the chips being conveyed thither from the country. A model of a much better still, which was contributed from Formosa to the Paris Exhibition in 1878, is perhaps referring to a town manufacture.
Camphor is brought from the interior to Tamsui, the chief port of Formosa, the baskets holding about half a pecul each (1 pecul = 133⅓ lbs.), lined and covered with large leaves. Upon arrival, it is stored in vats holding from 50 to 60 peculs each, or it is packed at once in the tubs, or lead-lined boxes, in which it is exported. From the vats or tubs there drains out a yellowish essential oil known as Camphor Oil, which is used by the Chinese in rheumatism.[1899] In 1877 hydraulic pressure has been established for the separation of the oil and moisture; the raw camphor loses about 20 per cent. of these admixtures.
Kämpfer in his account[1900] of the manufacture of camphor in the Japanese province of Satzuma and in the islands of Gotho, describes the boiling of the chips in an iron pot covered with an earthen head containing straw in which the camphor collects. In the province of Tosa, island of Sikok, there is now a still in use, which is quite conveniently combined with a cooling apparatus consisting of a wooden trough, over which cold water is flowing.[1901]
Purification—Camphor as it is exported from Japan and Formosa requires to be purified by sublimation. The crude drug consists of small crystalline grains, which cohere into irregular friable masses, of a greyish-white or pinkish hue. Dissolved in spirit of wine, it leaves from 2 to 10 per cent. of impurities consisting of gypsum, common salt, sulphur, or vegetable fragments.
In Europe, crude camphor is sublimed from a little charcoal or sand, iron filings or quicklime, and sent into the market as Refined Camphor in the form of large bowls or concave cakes, about 10 inches in diameter, 3 inches in thickness, and weighing from 9 to 12 lb.[1902] Each bowl has a large round hole at the bottom, corresponding to the aperture of the vessel in which the sublimation has been conducted. This operation is performed in peculiar glass flasks termed bomboloes, in the upper half of which the pure camphor concretes. These flasks having been charged and placed in a sand-bath, are rapidly heated to about 120°-190° C. in order to remove the water. Afterwards the temperature is slowly increased to about 204° C., and maintained during 24 hours. The flasks are finally broken.
As camphor is a neutral substance, the addition of lime probably serves merely to retain traces of resin or empyreumatic oil. Iron would keep back sulphur were any present.
In the United States the refiners use iron vessels; their product is in flat disks, about 16 inches in diameter by one inch in thickness.
The refining of camphor is carried on to a large extent in England, Holland, Hamburg, Paris, Bohemia (Aussig), in New York and Philadelphia. It is a process requiring great care on account of the inflammability of the product. The temperature must also be nicely regulated, so that the sublimate may be deposited not merely in loose crystals, but in compact cakes. In India where the consumption of camphor is very large, the natives effect the sublimation in a copper vessel, the charge of which is 1½ maunds (42 lb.): fire is applied to the lower part, the upper being kept cool.[1903]