PART V.—MORE OR LESS VOLATILE POISONOUS SUB¬ 
STANCES CAPABLE OF BEING SEPARATED BY DIS¬ 
TILLATION FROM NEUTRAL OR ACID LIQUIDS. 
HYDROCARBONS—CAMPHOR—ALCOHOL—AMYL NITRITE- 
ETHER—CHLOROFORM AND OTHER ANAESTHETICS— 
CHLORAL — CARBON DISULPHIDE — CARBOLIC ACID— 
NITRO-BENZENE—PRUSSIC ACID—PHOSPHORUS. 
I.—Hydrocarbons. 
1. PETROLEUM. 
§ 143. Petroleum is a general term for a mixture of hydrocarbons of the paraffin 
series, which are found naturally in certain parts of the world, and are in commerce 
under liquid and solid forms of various density. Crude petroleum is not imported 
into England, the original substance having previously undergone more or less recti¬ 
fication. The fighter and more volatile portions are known under the name of cymo- 
gene, rhigolene, gasolene, and naphtha. 
§ 144. Cymogene has a specific gravity of -590, and boils at 0°. It has been 
employed in refrigerating machines. It appears to consist chiefly of butane (C 4 H 10 ). 
§ 145. Rhigolene is now used in medicine in the form of spray to produce local 
anaesthesia. It boils at 18°, and has a density of -650. 
§ 146. Gasolene has a density of -680—688 ; it has received technical applications 
in the “ naphthafising ” of air and gas. 
§ 147. Benzoline (mineral naphtha, petroleum naphtha, petroleum spirit, 
petroleum ether, petrol) is a mixture of the fighter series of hydrocarbons ; the 
greater part consists of heptane, and there is also a considerable quantity of pentane 
(C 5 Hi 2 ) present. The specific gravity varies from -69 to -74. It is very inflammable, 
and is used in motor cars, sponge lamps, and also as a solvent for gutta-percha, 
naphthalene, paraffin, wax, and many other bodies. The ordinary petrol that is 
used in cars has a gravity of -680—708 at 15° C. and a boiling-point of 85° C. It is 
much employed by the practical chemist. 
The similarity of the terms benzoline and benzene has caused benzoline to bo often 
confused with benzol or benzene, the leading constituent of coal-tar naphtha (C 0 H 6 ). 
Mr Allen 1 gives in the following table a summary of the chief points of distinction, 
both between petroleum naphtha, shale naphtha, and coal-tar naphtha. The table 
is founded upon the examination of particular samples, and commercial samples may 
present a few minor deviations. 
1 Commercial Organic Analysis, vol. ii. p. 31. 
139 
