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. 
