26 



AGRICULTURE HANDBOOK 134, U.S. DEPT. OF AGRICULTURE 



lateral lines, and a ^/4-inch main line equals two 

 V2-inch lateral lines. 



When a graded course having a uniform 

 downward pitch to the tank lines is impossible 

 because of the contour of the land, the main 

 lines should be suspended from overhead guy 

 wires or cables. Suspended installation is espe- 

 cially suited for long runs of rnain lines over 

 very rough, rocky land, gullies, ravines, and 

 valleys. A properly installed main line will 

 drain itself. 



Tapping nnd Droplines 



If trees are tapped and droplines are installed 

 by a three-man team, the first man locates the 

 position for the taphole and bores the hole. He 

 sanitizes the bored hole either by syringing it 

 with the hypochlorite solution or by inserting a 

 germicidal pellet. The second man carries the 

 dropline assembly and attaches it to each tap- 

 hole by driving the spout firmly into the tap- 

 hole. The third man furnishes droplines, hy- 

 pochlorite solution, and other supplies to the 

 first two men. 



PN-4-41 

 unction of several main lines with surge 

 tank and vent. 



PN-4-40 



Figure H- — Main line used to transport sap across 

 inaccessible area. 



Figure J,6. — Main lines transport sap to storage tank at 

 the evaporator house. 



