AMERICAN INSTITUTE. 427 



mon turpentine has been distilled for common spirit of turpen- 

 tine or oil of turpentine. The black resin of Colophony, is the 

 cooled brittle mass in the state in which it leaves the mill. The 

 amber or yellow colored is the same resin mixed with about one- 

 eighth part of water, while it is yet fluid. 



Mastic is from the Pistacia lentiscus of Africa, a very common 

 shrub in Northern Africa. 



Botany Bay gum, a yellow resinous exudation from the Xan- 

 thorrhea hastilis and other species of the grape tree of Australia. 



The gum resin of the New-Zealand flax (Phormium tenax) is 

 admirably adapted for sealing letters. It is insoluble either in 

 water or spirit, and so thoroughly penetrates the envelope as to 

 become part and parcel of it; nor is it possible to get at the con- 

 tents of a letter so sealed. 



One of the gum trees of Popayan, in Columbia, yields a resin so 

 remarkably tenacious that when used to varnish ornamental work 

 it resists boiling w^ater and acids; tables, &c., so varnished by the 

 Indians, are much valued in Quito. 



Amber. 



The source of it was long unknown, by some considered a car- 

 bonaceous mineral, but now it is universally supposed to be a 

 vegetable resin, the product probably of a pinus (pine tree.) The 

 beautiful black varnish used by coachmakers is a very carefully 

 prepared compound of amber, asphaltum, linseed oil and oil of tur- 

 pentine. Our chief supplies of amber are from Prussia, on the coast 

 between Memel and Koningsberg. Late imports are about 40 cwt. 

 yearly. Large deposits of it w^ere found a few years ago in some 

 lakes on the eastern coast of Courland, not far from the Gulf of 

 Riga. In January, 1854, a bed of yellow amber, apparently of 

 great extent, was found on sinking a well at Prague, from w^hich 

 pieces, weighing tw^o and three pounds, w^ere extracted. The 

 largest block known is in the Royal Cabinet of Berlin, and w^eighs 

 thirteen pounds. This fossil is also found in Madagascar, Japan, 

 on the shores of the Indian Archip»elago, and in small quantities 

 on the coast of China. 



JjAc. 

 This important resin is from the incrustation made by an insect, 

 the Coccus-lacca. The lac is formed by it into cells somewhat 

 like the honeycomb, in which the insect is generally found entire, 

 and owing to whose presence stick-lac yields by proper treatment 

 a red dye, nearly if not quite as bright as cochineal. 



