162 



volatile fluid, and used as a substitute for turpentine, and 

 for dissolving caoutchouc. 



2. Illuminating Oil, extracted above 120°, and having a 

 specific gravity below 0.820. 



3. Lubricating Oil, including all the products of distilla- 

 tion above a specific gravity, 0.820, and found in many par- 

 ticulars superior to all other lubricating materials. 



4. Parqffine, separated by cooling the heavier lubricating 

 oils, and used for the manufacture of candles. 



VI. Illuminating Power. — Of course the price per gal- 

 lon is no criterion by which we may judge of the economy 

 for illuminating purposes of different fluids. The ordinary 

 burning fluid which, until the present greatly increased price 

 of turpentine, was the cheapest per gallon of all known 

 fluids, notwithstanding this was, for illuminating purposes, 

 when the quantity of light was taken into account, more 

 expensive than the most expensive sperm oil. The experi- 

 ments of Prof. Booth and Mr. Garnet of Philadelphia, are 

 interesting and conclusive upon the subject of the relative 

 illuminating power of Petroleum. Their experiments were 

 directed to determine the relative light furnished by dif- 

 ferent substances as compared with common coal gas. The 

 following were the results obtained by them, which I find 

 copied into the London Review : 



2.599 gallons Petroleum, gave a light equal to 1000 cubic feet Gas. 

 11.699 " Burning Fluid, " " " " 



35.53 lbs. Paraffine, 11 

 41.16 " Spermaceti, 11 " " 



47.18 " Adamantine, " " " " 



The relative cost of these equivalents was as follows : 



Gas, $2.12 



Petroleum, 1-06 



Paraffine Candles, 11.99 



Adamantine, 12.43 



Spermaceti, 20.16 



From these data there is no difficulty in concluding that 



