THE NAVAL STORES INDUSTRY. 29 



DISTILLATION PROCEDURE. 



The still is charged by removing the still head and gooseneck and 

 dumping in the gum from the barrels. After most of the dip has 

 run from the barrels they are thoroughly drained over a special 

 trough. It is hard to remove the dip from the barrels during cold 

 weather, and distillation is not carried on extensively in winter. 

 When scrape is distilled alone, and the still is hot from the previous 

 run, it is customary to pour in 5 or 6 buckets of water or a couple 

 of barrels of dip to cool off the still and prevent the first scrape put in 

 from " burning." 



After the still has been charged the cap is put on and connected 

 with the worm by means of the gooseneck. The joints are then 

 luted with clay. The fire is started under the still, and its intensity 

 regulated solely by the peculiar noise made by the gum during dis- 

 tillation. Crude gum always contains a certain amount of water 

 (from 5 to 10 per cent), and since the gum melts rapidly, a mixture 

 of oil and water soon appears at the end of the worm. A distilla- 

 tion requires from 2 to 2J hours; all the water originally present 

 distills over during the first one-half to three-fourths of an hour. 

 The "stiller" follows the course of the distillation by placing his ear 

 near the lower end of the worm, where the characteristic sounds made 

 by the boiling gum are most audible, and by examining portions 

 of the distillate collected in an ordinary drinking glass and noting 

 the proportions of water and turpentine. The point at which addi- 

 tional quantities of water should be added is indicated by a pecul- 

 iar strident sound, characterized as the "call for water." 



The water added is obtained from the top of the cooling tank. It 

 flows from a cock, by which the size of the stream is regulated, by 

 way of a trough into the still through a funnel placed in an opening 

 in the cap. The water at the top of the tank is always warm, and 

 often very hot. Some distillers obtain this water from the bottom 

 of the tank, claiming that the distillation is easier to regulate with 

 cold water. About 2J barrels of water are run in for each distilla- 

 tion, the amount varying with the size of the charge. 



The critical period during distillation is passed when all the water 

 in the gum has been driven over, since as the water is vaporized it 

 swells the viscous gum to such an extent that it may overflow into 

 the worm or escape through the joints, provided sufficient space has 

 not been left in the still for this expansion. "Dip" and "scrape" 

 from high faces are especially likely to boil over. The tendency to 

 foam over is indicated by the sound of tumultuous boiling at the end 

 of the worm. When this occurs the fire is urged as rapidly as pos- 

 sible, the resinous chips obtained by skimming the gum usually 

 being added, and the increased temperature maintained until the 



