bldridoe.] ASPHALT AND BITUMINOUS EOCK DEPOSITS. 
297 
Classification, or grouping, of natural and artificial bituminous compounds. 
Mixed with limestone (''asphal- rSeyssel, Val de Travers, Lobsan, Illinois, 
tic limestone "). I Utah, and other localities. 
Mixed with silica and sand ("as- r California, Kentucky, Utah, and other 
PQ 
phaltic sand''). 
Mixed with earthy matter ("as- 
phaltic earth " ) . 
Bitnminons schists 
I localities. " Bituminous silica." 
•J Trinidad, Cuba, California, Utah. 
jCanada, California, Kentucky, Virginia, 
and other localities. 
pn • , J Thick oils from the distillation of petro- 
leum. ''Residuum." 
Viscous. 
Gas tar. 
Solid 
I Pitch. 
Refined Trinidad asphaltic earth. 
Mastic of asphaltite. 
Gritted asphaltic mastic. 
Paving compounds. 
A glance at the above tables will convince one of the impossibility 
of establishing hard and fast lines between the substances enumerated. 
The classification, however, seems to the writer to be the most satis- 
factory of the several attempts met with in the literature of the 
subject. 
It will be observed that there has been omitted from the table one 
of the commonest terms in use, ' ' asphalt," or ' ' asphaltum. " By many 
disinterested authorities this word is restricted to the solid forms of 
the purer bitumens, forms including those grouped by Professor Blake 
under the general derivative, "asphaltite." This usage is reasonable, 
and by adhering to it confusion will be avoided in both science and 
trade. Industrially, however, the word "asphalt" is unfortunately 
made to include almost every compound of bitumen with a foreign 
material, chief among the latter being sandstone and limestone. 
Mr. Clifford Richardson, in his Nature and Origin of Asphalt, a 
contribution (October, 1898) from the laboratory of the Barber 
Asphalt Paving Company, gives the following definition of asphalt : 
The natural bitumen, which is known as asphalt, is composed, as far as we have 
been able to learn, of saturated and unsaturated dicyclic, or «polycyclic, alicyclic 
hydrocarbons and their sulphur derivatives, with a small amount of nitrogenous 
constituents. Asphalt may, therefore, be defined as any hard bitumen, composed 
of such hydrocarbons and their derivatives, which melts on the application of heat 
to a viscous liquid; while a maltha or soft asphalt may be defined as a soft bitu- 
men, consisting of alicyclic hydrocarbons, which, on heating, or by other natural 
causes, becomes converted into asphalt. The line between the two classes can 
not be sharply drawn. 
- "Bitumen," also, is a term that has been omitted from the table, 
although its adjective, "bituminous," is employed. The word 
a In the original report the word "or" was inadvertently placed after instead of before 
" poly cyclic. 1 ' 
