, 
iLDRiDGE] ASPHALT AND BITUMINOUS ROCK DEPOSITS. 299 
of lintaite itself is exceedingly brittle, one of its leading features, devel- 
>ped in the manufacture of black japans and varnishes made from it, 
s this very property of elasticity, attainable in such perfection in no 
)ther hydrocarbon compound except elaterite and wurtzilite. 
Elaterite, though elastic, is quite distinct from wurtzilite. Dana, 
n remarking upon the results attained by the authorities which he 
consulted, states that this substance "appears to be partly a carbo- 
lydrogen near ozocerite and partly an oxygenated insoluble material." 
The viscous bitumens of the table vary markedly in consistency. 
Maltha has the greatest fluidity, brea and chapapote the least — these 
ire, in fact, solids. Each member of the group shades into the next 
m either side, even maltha into petroleum and chapapote into the 
isphaltites. From this it will be inferred that the application of the 
several terms is decidedly indefinite. In regard to brea and chapa- 
pote, usage seems to make them synonymous, unless it be that the 
solidity of chapapote is a degree greater than that of brea, by no 
means an assured distinction. 
The viscous compounds stand between the solid asphaltites on the 
one hand and petroleum on the other. "The fluid kinds," observes 
Dana, "change into the solid by the loss of volatile matter by a proc- 
ess of oxidation which is said to consist first in the loss of hydrogen 
and finally in the oxygenation of a portion of the mass." 
Richardson, in his Nature and Origin of Asphalt, observes: 
Asphalts are distinguished by the large amount of sulphur they contain, and it 
is to its presence that many of the important characteristics, and perhaps, in part, 
the origin of this form of bitumen, is due. The soft asphalts or malthas contain 
much less sulphur than the harder ones, or if the former are rich in sulphur, they 
are then in a transition stage and will eventually become hard. But a small por- 
tion of the constitutents of a hard asphalt are volatile even in vacuo, but they can 
| be separated by solvents into an oily portion, which is soft, or softens readily when 
heated, and a harder portion, which does not melt by itself without decomposition, 
and is a brittle solid, but soluble in the oily or softer portion. The harder and 
least soluble portion always contains the larger part of the sulphur. It seems, 
therefore, that sulphur is the effectual hardening agent of [many] natural asphalts, 
in the same way that it is of artificial asphalts which are produced by heating a 
soft natural bitumen with sulphur. 
But Mr. Richardson adds that "some natural bitumens occur which 
have become hardened in another way and perhaps by oxygen." This 
refers particularly to the asphaltites. 
Boussingault's investigation, in 1837, into the composition of asphalt 
also developed son 3 results of especial interest. He took for his 
experiments the viscid bitumen of Pechelbronn, France. At a temper- 
ature of 230° C, in an oil bath, he separated an oily liquid, to which 
he gave the name "petrolene," regarding it as the liquid constitu- 
ent of bitumen, which, mingled in varying quantities with a solid sub- 
stance, "asphaltene," forms the bitumens of different degrees of 
fluidity. He describes asphaltene as brilliant black in color and luster, 
