PINE-OIL AND PINE-DISTILLATE PRODUCT EMULSIONS. 3) 
combustion being controlled by partially covering the wood with 
earth. Tar and charcoal were the only products recovered. Then 
came the beehive oven, operated in much the same way, which re- 
covered the more volatile parts of the distillate. 
‘The first retort plant, started about 1872 (14) (19), was not very 
successful for a time. It consisted of a series of retorts heated by 
fires underneath, and all the distillate was run together. This prod- 
uct was used mainly for the preservation of wood. Many people 
were experimenting with the idea, however, so that by 1888, accord- 
ing to Clark (5), the process of destructive distillation as appled to 
wood (longleaf pine) was an established and growing industry in - 
the Southern States. 
During this period many patents were taken out and many varia- 
tions in the method of distillation were tried. The products marketed 
were charcoal, tar, pitch, creosote oils, and light oils. The light oils, 
which contained turpentine and pine oil, were not refined. In fact, 
it was not until about 1900 (7) that wood turpentine came into com- 
mercial notice, and even then the samples contained so many impuri- 
ties that they could be used only for certain purposes and could be 
sold only at a decided reduction on the price for gum turpentine. 
Since the market for these oils was limited, the makers turned to 
the specialty market and sold them for secret uses, so that very often 
it was the maker who had the best selling agency, not the best plant, 
that succeeded. French and Withrow (7) cite the case of one firm 
having 100,000 gallons of a certain oil which they could not sell at 
5 cents a gallon, while another firm could not supply its customers 
at 18 cents a gallon with the same product, but would not buy from 
the first for fear of future competition. The oils were used for 
paints, varnishes, stains, insecticides, disinfectants, medicinal prod- 
ucts, and numerous other things. 
After 1902 (23), when the steam-distilled wood turpentine came on 
the market, the destructive wood turpentine was also more thor- 
oughly refined. Indeed, so much of the unpleasant odor was elimi- 
nated that in many instances it could be made to take the place of 
gum turpentine. About the same time the pine oil was also refined to 
a higher degree, and came to be commercially known as such, al- 
though it is still marketed also under various trade names. 
At present the products of distillation are more or less standard- 
ized, but the plants vary in minor details. The capacity of the re- 
torts varies from 1 to 11 cords. The retorts may be cylindrical or 
rectangular in cross-section and either horizontal or vertical. Some 
of them are heated by fires directly underneath and some by hot gases 
drawn through flues in the retort. The retorts also are heated to a 
higher temperature during the distillation in some plants than in 
others. The details depend to a large extent on the ideas of the man 
