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 applied 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 

 liigher temperature during the distillation in some plants than in 

 •others. The details depend to a large extent on the ideas of the man 



