204 ANNUAL OF SCIENTIFIC DISCOVERT. 



benzine, and naphtha; and wherein danger is to be apprehended 

 in the use of these liquids for ilhuiiinating purposes." 



*' This committee would respectfully report that after careful 

 examination they find that the term naphtha is a general term, 

 and covers both the other terms. The word naphtha is one of 

 great antiquity; it has long been applied to certain springs in 

 Persia from which is obtained a volatile, limpid, bituminous liquid, 

 having a strong, peculiar odor, and generally a light-yellow color. 



" When the art of distilling coal tar became known, the same 

 term was applied to the more volatile products of such dis- 

 tillation ; the heavy products being called dead oil and asphal- 

 tum. The term was next applied to the most volatile products 

 from the distillation of coal for oil. When petroleum took the 

 place of coal for this purpose, the term naphtha was again used 

 to distinguish the more volatile, so-called Might' products from 

 the heavier ones. This is still its use, and in our market all vola- 

 tile products of petroleum lighter than illuminating oil (or what 

 is known among our dealers as * kerosene,' which has a specific 

 gravity of eight-tenths or 45° by Baume's Hydrometer), are des- 

 ignated by the general name of naphtha. 



** Of the naphthas those of a gravity from 45° to 80° B. are 

 often, though improperly, called benzine or benzole. True ben- 

 zole is a product of coal tar, and differs essentially from any 

 liquid obtained from petroleum. The term * gasoline ' is applied 

 to all naphthas having a specific gravity lighter than about 80° B., 

 the lightest known being about 90°. 



"This committee find, however, by reference to Professor C. M. 

 Warren's unpublished determinations, that none of these products 

 are simple bodies. All of them are mixtures, in indefinite pro- 

 portions, of at least 12 hydrocarbons, distinguished from each 

 other by their boiling-points, which vary from 32 to 318° F., and 

 are nearly as follows : 32, 47, 86, 99, 142, 156, 195, 208, 247, 261, 

 303, and 318°. 



"While gasoline contains mostly those hydrocarbons wdiose 

 boiling-points are low, kerosene is composed chiefly of those 

 whose boiling-points are comparatively high. The isolation of 

 any one of these products being a matter of great difficulty, few 

 have attempted it, and your committee have had to rely on the 

 labors of a fellow-member for much valuable information on the 

 subject. To completely separate the constituents of any sample 

 would be the labor of many months. 



" Your committee also report that there is great danger from 

 the careless use of naphtha, — first, on account of its great inflam- 

 mability ; and, second, from the liability of forming explosive mix- 

 tures of the air and vapors. The liquids are not in themselves ex- 

 plosive, neither are the vapors ; but both are highly inflammable. 

 If the liquids escape by any means and f<n-m pools, or saturate 

 porous substances, the near approach of flame may cause the 

 vapor to ignite and set fire to the whole exposed surface of the 

 liquid. 



"The vapors, it is true, are not explosive, but they become so 

 when mixed with air in certain proportions, anil this committee 



