THE NAVAL STORES INDUSTRY. 31 



from 6 to 8 mesh, the second 14 mesh, the third 32 mesh, and the 

 bottom 60 mesh. The bottom screen is covered with a layer of 

 cotton batting to remove the finer particles of dirt. 



The rosin remains in the vat from a few minutes to an hour, accord- 

 ing to the temperature at which it left the still. It is next dipped 

 into crude barrels made on the spot, holding about 450 pounds net. 

 If dipped while too hot and fluid, considerable leakage occurs between 

 the staves, which may in a measure be prevented by luting with clay. 

 The rosin requires about 24 hours to become solid. 



The cotton batting, after being used to strain the rosin, is known as 

 "batting dross" or "rosin dross." As cotton is very absorptive, a 

 large amount of rosin is retained. Recent analyses made by the 

 Forest Service indicated that rosin dross contains from 75 to 90 per 

 -cent by weight of rosin. 



It has been the practice to burn under the still a certain portion of 

 the chips removed by skimming and in the screens, and to throw 

 away the rest. In this way, piles of discarded chips often grew to 

 large size before the stills were moved. Such piles, of course, contain 

 considerable rosin, and during 1911 and 1912, owing to the high price 

 of naval stores, operators found it profitable to sell not only the dross, 

 but the skimmings and similar material to extraction plants. 



TREATMENT OF THE TURPENTINE. 



The distillate issuing from the worm, and consisting of a mixture of 

 water and turpentine, runs into an ordinary 50-gallon barrel, where 

 the separation of the water and turpentine takes place by gravity; 

 the turpentine, bemg lighter, floats on the top. The bottom of this 

 barrel contains an opening, closed with a long wooden plug, by which 

 the excess water is allowed to escape as the volume of the distillate 

 increases. In most cases a second container, consisting of a barrel 

 whose upper half has been sawed off, receives the turpentine flowing 

 from the top of the first barrel through a short pipe, to permit of more 

 perfect separation. A thin yellow scum forms the line of demarca- 

 tion between the water and turpentine. The latter is dipped out 

 carefully and poured directly into the barrels in which it is sent to 

 market. 



The first runnings of turpentine are colored more or less green with 

 copper salts, due to the action of acetic and resin acids on the copper 

 of the worm and still. The green color is especially noticeable when 

 the still is first used after a period of idleness. When the still is in 

 continuous use the color in the first runnings is very slight. 



The turpentine barrels must be thoroughly tight. They are usually 

 made of sound white oak, thoroughly driven, and coated on the inside 

 with glue. Each barrel holds about 50 gallons, some space being 

 left for expansion of the contents. 



