THE MORE IMPORTANT PLANT PRODUCTS 69 



is also claimed by the former. When the tree has attained a 

 diameter of about 6 inches, tapping for varnish commences, 

 and this operation is continued at intervals until the tree is 

 50 or 60 years of age. If the tapping is too severe, or the 

 trees too young, injury or death ensues. The tapping opera- 

 tion is begun in late June or early July at a time corresponding 

 with the opening of the flowers, and is continued throughout 

 the summer. Oblique incisions from 4 to 12 inches in length, 

 and about i inch in width, are made in the bark of the tree down 

 to the wood, and the sap which exudes is collected in shells, 

 bamboo tubes, and similar receptacles. Wooden pegs are driven 

 into the trunk to facilitate climbing, in order to reach the main 

 branches. The tapping is done early in the morning and the 

 sap gathered from the receptacles into which it has flowed 

 from the incisions each evening. In showery weather it dries 

 rapidly, and often has to be scraped away. The sap continues 

 to exude from the wound for about seven days, and then 

 a fresh, thin slice of bark is removed, which causes another 

 exudation. This is repeated seven times with an interval of 

 about seven days between each operation, so that the work on 

 each tree occupies about fifty days. After being tapped, the 

 tree is allowed a period of from five to seven years to recover ; 

 the old wounds are then reopened and fresh ones made. A 

 arge tree yields from 5 to 7 lbs. of varnish. This, as it 

 exudes, is pure white in appearance, but quickly oxidizes to 

 greyish-white, changing to black. To prevent contact with 

 the air the crude varnish is covered as soon as possible with 

 layers of oil-paper. 



Crude varnish furnishes only one colour, namely, black, and 

 when applied to wood floors, or pillars, is the most indestructible 

 varnish known. To obtain brown varnish " P'ei-yu " {ante, 

 p. 66) is added, in the proportion of 25 to 50 per cent., to the 

 crude varnish, according to the shade of brown required. The 

 more " P'ei-yu " added, the quicker the varnish will dry. Red 

 varnish is produced by adding cinnabar (mercuric sulphide) 

 to brown varnish in about equal parts. Yellow varnish is 

 obtained by adding to the " brown varnish " orpiment (arsenic 

 sulphide) in slightly less than equal quantity. 



Enormous quantities of raw varnish are exported from 



