594 On the Kukumb ka Tel. [Nov. 
The result of various trials satisfied me, that this substance could 
not be brought to congeal at a higher temperature than 90°; but in 
experimenting on it in the solid state, that temperature was found 
quite insufficient, by several degrees, again to liquify it. The follow- 
ing is a brief statement of the result of several trials to ascertain its 
melting point. It was subjected to a gradually increasing temperature, 
commencing from 90°, with considerable intervals between every 
higher accession of temperature, to allow time for the effect which was 
capable of being produced on it. From 90 to 100°, the effect was 
merely to soften it: at 102°, it still preserved its cohesion, but the con- 
sistency was that of butter in warm weather: at 106 part began to 
separate in a semifluid state, transparent at the edge and opaque in the 
centre; and a few minute globules were separately observed in a per- 
fectly fluid state. Every fresh accession of temperature had of course 
the effect of bringing it more and more towards a state of fluidity; but 
up to 116°, there was still observable a partial opacity, and it was only 
when the temperature had reached about 120°, that it could be said to 
have attained perfect fluidity and transparency*. 
Another peculiarity in this substance is the irregular form its sur- 
face is thrown into in the act of concreting. Nor does it appear capable 
of being prevented by any management, or by conducting the process 
in the most gradual and gentle manner. But the effect may be consi- 
derably increased by exposing it in a fluid state to the sudden applica- 
tion of a cooling medium. Having a stratum of the fluid oil at 120°, 
floating on water in a small cup, I suddenly exposed it to the chilling 
influence of a slight drizzling rain and sharp breeze, the temperature 
of the air being 70°: the rapid abstraction of heat soon caused the 
congealing process to commence, and the entire surface shot up into a 
series of prismatic or columnar masses, about 4th inch in height, and 
separated from each other by small intervals. This effect took place 
some time before the substance became perfectly opaque; and while 
in this state, it had the appearance of a crystallized body, in an 
intermediate state between opacity and transparency, of which we have 
a familiar instance in a piece of loaf-sugar dipped in water. 
The concrete oil of the mangosteen might I apprehend be advan- 
tageously introduced into pharmaceutical preparations. It is used by 
the natives as a healing application. I have noticed among its sensi- 
ble properties, that it impresses a sensation of cold on the tongue; 
from which it would appear, that it powerfully absorbs heat, as several 
salts do in the act of dissolving. It is easy to conceive that this 
* The same peculiarity is observable, more or Jess, in all the concrete oils : itis 
probably owing to their bad conducting power.—Ep. 
