201 
The oil redistilled at 17 millimeters, possessed the characteristic odor of the 
resin, and was very light yellow in color. Boiling point, 132° to 140° (17 milli- 
tila Specific gravity, (=) = 0.9056. 
The mayapis resin was light colored, apparently homogeneous in com- 
position, and so viscous that it could scarcely be poured. When heated to 
100° it hardened, and exposure to the air produced the same effect, 
changing it to a pearly, white solid. It dries much more rapidly than 
do either Balao or Malapaho. The scientific name of the tree yielding 
Mayapis resin is Dipterocarpus anisoptera vidaliana, and Mr. Merrill 
states that this species has never been encountered outside of the Philip- 
pines. Most of the properties of the sample I worked with—namely, 
the high per cent of water, behavior on heating, low percentage of oil, 
consistency, and boiling point of the oil——are different from those gen- 
erally given for gurjun balsam. 
Balao and Malapaho are largely used by the natives of the Philippines 
for purposes I have already mentioned, but their application is due to a 
lack of better material. As varnishes they dry too slowly ever to be 
considered by the side of modern products. Balao is superior to the 
other in this respect and gives a very tough and durable coating. The 
drying properties of these wood oils might be enhanced by the addition 
of drying oils were it not for the fact that the admixture is not practi- 
cable. If practical uses are ever discovered for sesquiterpene oils, then 
these resins may be of value as a source of the latter, also the products 
of destructive distillation which have been previously discussed probably 
largely consist of sesquiterpenes, and at the same time the higher boiling 
and more viscous portions produced by this decomposition could be put 
to uses similar to those of rosin oil, 
Sesquiterpenes.—Bodies of this type in small quantities have been 
known for many years, as they occur in nearly all the essential oils of 
commerce, but the latter generally are expensive and their constituents 
have been looked upon as rare substances. It is unfortunate and strange 
that the sesquiterpenes of copaiba and gurjun have never been the subject 
of serious study. The latter products, as well as those considered in 
this article, are very largely composed of sesquiterpenes, so that if a 
demand were ever created for chemicals of this type there would be an 
abundant supply. The sesquiterpenes would probably be inferior to 
terpenes for most of the present uses of the latter because of their 
being practically nonvolatile. However, this property might allow of 
their use as solvents in various industrial operations where turpentine is 
inadmissible. Just as is the case with turpentine, they dry slowly in 
the air, forming a tough varnish, and they might, to a limited degree, 
profitably be used with the latter for the thinning of paints and varnishes. 
In this connection one other point is to be considered. The sesquiter- 
penes have never received the thorough investigation which they merit 
