THE NAVAL STORES INDUSTRY. 35 



Two kinds of scrape are distinguished in France. The hardest 

 kind adhering firmly to the face is called "barras," while the soft 

 scrape is called "galipot." The tool used (Plate IX-1) for remov- 

 ing the scrape resembles that used in removing the outer bark, 

 except that the blade is only 1-| inches wide. Usually the trees are 

 scraped but once a season, in November, but sometimes an additional 

 scraping is made in June. 



The method of collecting the crude gum is practically identical 

 with that used in America. 1 The resin is temporarily stored in 

 wooden tanks sunk into the ground at convenient points in the 

 forest until it is ready to be transported to the still. 



FRENCH DISTILLATION METHODS. 



In French operations the barrels of resin as they come from the 

 forest are usually stored in large tanks, so as to form a reserve supply 

 to be worked up during the winter months when no resin is collected. 

 The storage tanks are sunk into the ground at a distance of 75 feet 

 from the still, and the resin transferred to the latter by means of an 

 overhead trolley. The tanks are built of brick or cement and cov- 

 ered with tile. 



PURIFICATION OF THE RESIN. 



The resin is often subjected to preliminary treatment previous to 

 distillation to remove the trash. This is not done, however, unless 

 high grade rosin can be produced which will bring a good price, since 

 the process results in loss of turpentine and requires extra fuel and 

 labor. 



The preliminary treatment involves fusion, clarification, decanta- 

 tion, and straining. The fusion is performed in open or closed pans. 



Open pans. — The resin is liquified in a cylindrical copper pan 6 feet 

 in diameter and 1£ feet in depth, with a slightly concave bottom. 



1 Comparison of yields of crude gum per inch of width of face, French and American methods: 



Data from French operations indicate an average yield of 1.8 liters of crude gum per face per year, or 4 

 pounds. 



If chipped 40 times yield per face per chipping=0.1 pound. 



If face is 3.5 inches wide yield per inch width=0.029 pound. 



If face is 4.0 inches wide yield per inch width= 0.025 pound. 



Data from American operations: 

 Crop A— 8,000 faces. (See page 25): 



206,235 pounds gum in 4 years= 6. 4 pounds per face per year. 

 43,633 pounds scrape in 4 years=1.4 pounds per face per year. 



Total 7.8 



If chipped 32 times yield per face per chipping= 0.244 pound. 

 If face is 12 inches wide yield per inch width= 0.020 pound. 

 If face is 14 inches wide yield per inch width= 0.017 pound. 

 Crop D— 8,000 faces. (See page 25): 



279,260 pounds gum in 4 years=8.7 pounds per face per year. 

 53,915 pounds scrape in 4 years= 1.7 pounds per face per year. 



Total 10.4 



If chipped 32 times yield per face per chipping= 0.325 pound. 

 If face is 12 inches wide yield per inch width=0.027 pound. 

 If face is 14 inches wide 'yield per inch width=0.025 pound. 



