THE NAVAL STORES INDUSTRY. 49 



EFFECT OF VARYING FREQUENCY OF CHIPPING ON YIELD CALIFORNIA. 



Table 20 shows the yields obtained from three similar sets of 50 

 faces, each chipped at 3, 5, and 7 day intervals for the same period. 



TABLE 20. Yields obtained by chipping at different intervals California (f>0 faces in 



each set). 



Over twice as much gum was obtained by chipping at 3-day inter- 

 vals as at 7-day intervals. 



SUGGESTIONS FOR SPECIFICATIONS. 



HANGING CUPS 



1. The distance from the ground to the apex of the first streak 

 shall not exceed 10 inches. 



2. No "blazes" or similar scarification of the tree shall extend 

 below the gutter or apron. The surface prepared for the placement 

 of the gutters or aprons shall not extend beyond the ends of the same. 



3. The peak of the first streak shall not be more than 2 inches 

 above the gutter or apron. 



4. The " streak" or gash made for the placement of the gutters or 

 aprons shall not penetrate the wood of the tree more than one-half 

 inch, the measurement to be taken from the dividing line between 

 the wood and bark. 



5. The gutters or aprons must be so attached that no "gum" flows 

 between the tree and the gutters or aprons, or flows over the edge of 

 same so as to fall without the cup or other receptacle. 



6. For the first three years the cups and gutters shall be raised 

 each spring to the top of the face worked the previous season. 



7. A bar or strip of live bark not less than 4 inches wide in the 

 narrowest place shall be left between the faces. 



CHIPPING. 



1. No tree under 10 inches in diameter shall be tapped. Minimum 

 diameter of tree to carry one face, 10 inches; minimum diameter of 

 tree to carry two faces, 16 inches; no tree shall carry more than two 

 faces. 



