(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 Dyera 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 ae 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* 
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. 
KowreeE or Kowree Copa 
This variety of copal, or varnish resin,—one of the best, 
—is found in a fossil condition in various portions of the 
*1 Unless otherwise specified, the varnish resins in this collection were presented 
by A. P. Bjerregaard, of New York City. 
