152 THE POPULAR SCIENCE MONTHLY. 



partly the result of an accident. The condenser of a still heated by- 

 direct fire and charged with 900 gallons of mixed heavy and light 

 oils, became partially closed, and the pressure caused leakage at the 

 bottom of the still. The fire was very gradually drawn, after 250 

 gallons of light oil had passed off. The next day the oil in the still 

 was found to be light-yellow, nearly odorless, neutral, and dense ; 

 the light, odorous hydrocarbons having been removed, at this low 

 temperature, without decomposing either the distillate or the oil in 

 the still. Further experiments perfected the process, which is greatly 

 aided by the admission of steam from an open pipe into the body of 

 the still during distillation. 



Mineral sperm-oil was the result of experiments by Messrs. J. and 

 R. S. Merrill on burning heavy lubricating oil and paraffine in lamps, 

 especially constructed for the purpose. The light was very "good, but 

 the liquid was too thick to ascend into the wick. To obviate this 

 the oil was subjected to a partially destructive distillation, " crack- 

 ing " it enough to render it mobile, but not volatile. 



The manner in which the crude petroleum is treated to obtain 

 these various products is briefly outlined here from Prof. Hayes's 

 sketch : The crude oil is heated by steam in upright, wrought-iron 

 cylinders, incased in wood, of 12,000 gallons capacity. About 15 

 per cent, of distillate passes off and is condensed in pipes surrounded 

 by water, yielding gasolene and A, B, and C naphthas, which are 

 separately collected. From the gasolene rhigolene can be obtained 

 by a second distillation with steam-heat, condensing the first portions 

 of the distillate by ice and salt; ten per cent, is obtained from the 

 gasolene. The steamed oil is pumped from the naphtha-stills into 

 small stills, holding 1,000 gallons each, and heated by direct fires. 

 Only carbon remains in these stills, some uncondensable gas escapes, 

 and the other products are : No. 1, crude illuminating oil ; No. 2, in- 

 termediate oils; No. 3, crude lubricating oil. Each of these is redis- 

 tilled in the same sort of still. No. 1 is agitated with sulphuric acid, 

 then with caustic soda, and distilled, yielding 80 per cent, of its 

 volume of finished kerosene (refined illuminating oil) and mineral 

 sperm-oil, and nearly 20 per cent, of denser oil. No. 2 is at once 

 redistilled, yielding chiefly crude lubricating oil. No. 3 is agitated 

 with sulphuric acid and then distilled with caustic soda in the still, 

 yielding mainly dense paraffine-oil. This is kept in wooden barrels in 

 ice-houses from seven to ten days, and deposits crystalline paraffine, 

 which is pressed in strong cloth bags, one above another, with sheet- 

 iron between, and yields crude paraffine-wax and heavy oil. The 

 paraffine is repeatedly recrystallized from solution in naphtha and 

 pressed, until it is white and pure enough for sale. The heavy oil is 

 heated in stills by direct fires, slowly increased, but kept as low 

 as possible, and generally with the admission of steam, until 20 

 to 30 per cent, has passed over. The residue is ready for sale, 



