(44) 



974- Specimen of balata from Dutch Guiana. Presented by the India Rubber 



World. 

 975-976. Other specimens of the same. Presented by A. E. Haughey, of New York. 



977. A balata-like product from near Para, Brazil. Its botanical origin is not 



known, but it is probably genuine balata. Presented by the India Rubber 

 World. 



978. Gutta Jelutong, or Pontianac. — The coagulated milky juice of a tree of Borneo, 



probably Dyer a costulata Hassk. {Apocynaceae — Dogbane Family). Pre- 

 sented by the India Rubber World. 



979. A gutta-percha-like product of unknown botanical origin. From the East 



Indies. Presented by H. H. Rusby. 



980. Almeidina gum or root rubber. Of unknown botanical origin. From Angola, 



western Africa. Presented by the India Rubber World. 



981. Rubber bark. — The bark of a tree of the Philippine Islands, the botanical 



identity of which has not yet been definitely ascertained. Presented by 

 Gravenhorst & Co., of New York City. 



Varnish Resins 21 



Resins are waste products resulting in the growth of 

 many plants, and existing in the plant dissolved in volatile 

 oil, the mixture known as oleo-resin. In this form they 

 are stored in various cavities in the wood and bark, whence 

 they can be obtained by cutting or puncturing the latter. 

 They very commonly exude spontaneously through acci- 

 dental punctures and fissures. Through the natural or 

 artificial evaporation of the oil, the resin results. Ad- 

 vantage is taken of this property to dissolve these resins 

 in various volatile solvents and paint the solution upon 

 objects to be varnished. The solvent then evaporates? 

 leaving a coating of the resin. Varnish resins are more 

 valuable in proportion as they are harder and less soluble. 

 The best of them are dug from the ground, where they 

 have long remained and become fossilized. The adultera- 

 tion of varnish consists chiefly in the addition of common 

 rosin and other inferior materials. Such varnish is not 

 durable. 



KOWREE OR KOWREE COPAL 



This variety of copal, or varnish resin, — one of the best, 

 — is found in a fossil condition in various portions of the 



21 Unless otherwise specified, the varnish resins in this collection were presented 

 by A. P. Bjerregaard, of New York City. 



