Page:The American Cyclopædia (1879) Volume III.djvu/674

 6C8 CAMPHOR hence the high price of the article. The Chi- nese, it is said, pay for it at the rate of $1,000 to $1,200 the picul (133 Ibs.), or for a very su- perior quality even $3,000 for 1 cwt. ; while the Japan article obtained in their ports, and hence known as Chinese camphor, is worth only from $12 to $15 the picul. The camphor- wood trunks are supposed to be made of the wood of this tree. It answers well for house ,-md ship timbers and articles of furniture, especially such as are intended to contain and preserve clothes. It is very easy to work, splits readily, and is never attacked by the many destructive insects of the East, which will so speedily devour any European woods, and even those of the East, except the teak, the calambuco, and the camphor. The young trees produce, instead of the full-formed cam- phor, a straw-colored fluid, which is called in the East Indies the oil of camphor, and is used as an external application in rheumatic com- plaints. This is supposed by Dr. Thompson to be the same substance as the solid product, the composition of which he represents by the formula CioH0. But the genuine oil of cam- phor he describes as the product of the same trees which furnish the camphor of European commerce. This is known in this country and in Europe as the camphor of Japan or com- mon camphor ; and of this two varieties are recognized in commerce : one, the Dutch, Japan, or tub camphor ; and the other, the Chinese or Formosa camphor. The latter is principally produced in the island of Formosa, and thence carried in junks to Canton. There it is packed in square chests lined with lead, and distributed to the various eastern ports at which we obtain it It is a crude article in dirty gray grains, agglutinated together in Comphora officinarum. lumps, and contaminated with many impuri- ties. The tub camphor is obtained in Batavia, whence it is exported in tubs securely covered with matting, and an outside tub, and con- taining 100 Ibs. or more. This is in pinkish- colored grains, coarser and purer in general than the Chinese. Both varieties are probably obtained from the same tree, the laurus cam- phora of Linnasus, or camphora officinarum of Nees von Esenbeck, an evergreen of consider- able size, resembling the linden tree, and bear- ing a red berry like that of the cinnamon. All parts of the plant possess the odor of cam- phor, and produce this article when cut into small pieces and distilled. The process is con- ducted in large kettles of iron, which are furnished with covers in the form of a dome, in which stalks of rice or grain are placed for receiving the camphor sublimations. But little water is used, and only a moderate heat applied to volatilize this and the camphor together. The latter condenses upon the straw. All the camphor of commerce is a crude article, which requires purification before it is fit for use. The art of refining it was long monopolized in Europe by the Venetians, and afterward by the Dutch ; and it is not long that we have in this country been independent of the latter for our supplies of the pure material. The crude article is introduced together with about ^ the quantity of quicklime into vessels of cast iron, which serve as retorts, and over which are placed covers of sheet iron connected with the lower vessels by a small aperture. A num- ber of these stills are placed in a large sand bath, and, after the melting of the camphor within them, kept at a uniform temperature, that the process may go on quietly. The quick- lime serves to retain the moisture, which would otherwise interfere with the condensation of the pure camphor. This takes place under the shelf upon which the cone stands, the vapor when in excess passing into the loosely affixed cones of sheet iron, care being taken to keep the hole open. The deposit of camphor is in the form of a circular cake an inch or two thick, with a hole through the centre. The composi- tion of camphor is represented by the formula CioHsO. Its specific gravity is 0'987 ; its melt- ing point is 288 F. ; and it boils at 400. It is a semi-transparent white substance, crystallizing in hexagonal plates, and with a crystalline frac- ture; soft, friable, and tough, so that it is diffi- cult to reduce it to powder. When moistened with a few drops of alcohol, it is easily pul- verized. Its taste is somewhat bitter and pun- gent, attended with a slight feeling of cold- ness; its odor is strong and fragrant, highly penetrating, and exceedingly noxious to trou- blesome insects. Exposed to the air, it soon disappears in vapor ; in close vessels it sublimes and crystallizes upon the parts most exposed to the light. It is readily inflamed, and burns with much smoke and light. A singular effect is noticed on dropping small pieces of clean camphor upon the surface of pure water. The particles rotate and move rapidly about, some- times for several hours. Any greasy matter touching the water will at once put a stop to the motions. This phenomenon has been shown