408 
Quid sit pulclirum, quid turpe, quid utiie, quid non.—H or. 
A Description of the Diseases and Accidents incidental to the 
Horse; wherein the Rock Oil of Barbadoes, or Green Mineral 
Naphtha, from its Medicinal Properties, has proved a parti¬ 
cularly useful Remedy; with plain Directions and numerous 
Formulas for its internal and external Use in Horses, Dogs, 
Cattle, Sheep, also, a Description of the True Rock Oil, 
whereby it may be distinguished from spurious Imitations . 
By B. Hart, Zoatrist . 
The liquid bitumens differing perhaps from the solid, only that 
the latter are consolidations of the former, have been subjects of 
considerable interest to the chemist, and have been periodically 
magnified into immense importance as therapeutical agents. We 
are old enough to remember when the tar water, so strenuously 
advocated by the idealist Berkeley, was still considered by some 
to be a panacea for all the bodily ills that flesh is heir to, and 
many a nauseous draught of it have we drunk. 
The bitumens, although classed among the mineral substances 
from the way in which they exude from the ground, are of vege¬ 
table origin, and in chemical properties do not differ materially 
from each other. Naphtha and Petroleum, the principal native 
bitumens, used to be thus distinguished. Naphtha, a very 
light oily substance, sometimes colourless, or of a light yellow 
colour, found floating on certain springs in Italy, and on the 
shores of the Caspian Sea, or procured artificially by distilla¬ 
tion from Petroleum, containing no oxygen, composed of an 
equal number of atoms of carbon and of hydrogen (Dr.Ure says 
one atom of oxygen to twenty-two of carbon and twenty of 
hydrogen)—liignly inflammable—undergoing' no change from 
contact with the atmosphere—insoluble in water—partially 
soluble in alcohol, and more so with sulphuric ether, and the 
fixed and volatile oils. Petroleum was thicker—less transparent— 
reddish brown, and greasy—thickens by exposure to air—in¬ 
soluble in water, and nearly so in alcohol—mixing with ether 
and the oils. It w as found principally in Barbadoes, but occurs 
in other parts of the world, and in the British Isles. Mineral 
tar differed from petroleum in being still thicker, and even com¬ 
mon coal tar yielded pretty nearly the same chemical analysis. 
Now, however, it seems that Naphtha and Petroleum must be 
used as almost synonymous terms, as Naphtha is a produce of 
