GOODYEAR ON GUM-ELASTIC. 



common resin is often substituted in part for the lac, and a mix- 

 ture of red lead and chalk for the cinnabar, The best black 

 sealing-wax consists of 60 parts of lac, 10 of turpentine, and 30 

 of levigated bone black ; the best yellow sealing-sax of 60 parts 

 of lac, 12 of turpentine, and 24 of chromate of lead, (Berzelius.) 

 Lao is also used as a varnish, and forms an excellent cement for 

 broken porcelain and earthenware." 



The following is an interesting account of this material, taken 

 from Ure's Dictionary. 



"Stick lac is produced by the puncture of a peculiar female 

 insect, called coccus lacca or ficus, upon the branches of several 

 plants, as thej^ci^^ religiosa, the, ficus indica, the rhaninus jujuha, 

 the croton lacciferum, and buteaf rondos a, which grow in Siam, 

 Assam, Pegra, Bengal, and Malabar. The twig becomes thereby 

 incrusted with a reddish mammelated resin, having a crystaline- 

 looking fracture. 



"The female lac insect is of the size of a louse; red, round, 

 flat, with 12 abdominal circles, a bifurcated tail, antennae, and 

 six claws, half the length of the body. The male is twice the 

 above size, and has four wings ; there is one of them to 5000 

 females. In November or December the young brood makes its 

 escape from the eggs, lying beneath the dead body of the 

 mother ; they crawl about a little way, and fasten themselves to 

 the bark of the shrubs. About this time the branches swarm to 

 such a degree with this vermin, that they seem covered with a 

 red dust ; in this case they are apt to dry up, by being exhausted 

 of their juices. Many of these insects, however, become the 

 prey of others, or are carried off by the feet of birds to which 

 they attach themselves, and are transplanted to other trees. 

 They soon produce small nipple-like incrustations upon the 

 twigs, their bodies being apparently glued, by means of transpa- 

 rent liquor, which goes on to the end of March, so as to form a 

 cellular texture. At this time the animal resembles a small oval 

 bag without life, of the size of a cochineal. At the commence- 

 ment, a beautiful red liquor only is perceived, afterwards eggs 



