China.] 



ORIENTAL COMMERCE. 



4y» 



double the price of a sapphire of the same size. There are three prin- 

 cipal species. The opal of Nonnius. This appears olive-coloured by 

 reflection, but when held between the eye and the light, is found to be 

 transparent, and of a beautiful ruby colour. The white opal lias its 

 ground of a white glass-like complexion, from whence green, yellow, blue- 

 ish, and purple rays arc thrown out ; but when held against the light, 

 appears of a reddish, or rather flame colour. The blucish and semi- 

 transparent opal is less valuable than the others, on account of its being 

 more easily imitated by art. 



Opals are to be met with in several parts of India, and at PaJera- 

 bang on Sumatra; but great caution is requisite in purchasing, as the 

 natives are very expert in imitating them. 



Ostrich Feathers. — The feathers of the ostrich are divided into 

 loose silky filaments. The long white plumes of the tail and wings have 

 always been highly esteemed. The feathers most admired are those which 

 arc plucked from the animal while alive, and are known by this property, 

 that the quill contains a moist substance, whilst those which arc pulled 

 after death, are dry, light, and liable to worms. 



The short feathers are most esteemed for female dresses. Those 

 from the Cape of Good Hope are not considered so good as those from 

 Barbary; they are of a better colour, but not so perfect in the flue or 

 feather, and run thin and ugly. The best are of a huffish tinge; the 

 grey and coloured are used for dying. The stalks of the large feathers 

 are heavy, and the edges of the feather broken and hairy ; these are of 

 little value, and should be rejected. 



Paddy-Bird Featheks somewhat resemble those of the ostrich, but 

 are much finer; they are of a cream colour, and should be chosen with 

 their tops not broken, the sides or Hue perfect, and the stem not bent ; the 

 larger they are, the more esteemed. 



Quicksilver, (Para s Hind., Parada, San.), or mercury, is sometimes 

 found in the earth in a fluid form, and is then called virgin mercury. The 

 principal mines are in Hungary and Spain. A quantity is also produced 

 at China, from whence it was formerly imported into Europe, hut of late 

 years it has been sent from Europe to China. 



The bt^pt quicksilver is of a shining silver colour, very fluid, appearing 

 to the eye like melted lead, or tin. The following are the best modes of 

 ascertaining its goodness: — Put a little into a silver spoon over a gentle fire; 

 if it is good, it will evaporate without leaving any impurity behind; but if 

 bad and drossy, the spoon will remain black. When strained through a 

 piece of leather, if good, it will leave no impurities behind, and be white. 



