74 METHO'DS OF OOMMUNICATION FOR FOREST PROTECTION 



The second method will be followed when the trees are scarce or when the other 

 method of construction is not practicable. ' The line should be run straight up the 

 side of the mountain. Brackets and glass insulators should be used, and the wire 

 tied to the outside of the insulator with No. 14 B.W.G., B.B., galvanized-iron wire, 

 which is very light and will break easily. About 4 ft. of slack should? usually be 

 allowed for a 100-ft. span. 



CHAPTER X 



EMEKGENOY LINES, CONSTKUOTION AND USE 

 Section 61 Use in Forest Protection 



For the purpose of quickly establishing telephone communication at points not 

 on a permanent line, the military system of laying light insulated wires on the ground 

 has been adopted. The more thoroughly organized the protection staff becomes, the 

 greater is the need for maintaining direct communication .between all its parts. 

 Emergency lines serve two main purposes in forest protection, but they are also 

 extremely useful in general administration work on forest reserves. In protection 

 work they have the following application: 



(1) To connect the ends of a permanent line across a break caused by forest 

 fire, landslide, or other serious d'amage to the line. This is required where it is 

 important that the use of the permanent line continue without interruption and where 

 the repairs will require some time. 



(2) To connect fire-camps, commissary camps, and other important points on the 

 fire-line or line of communication with headquarters in the rear. This is usually 

 accomplished by connecting the temporary camps with the nearest permanent tele- 

 phone line. Heliograph stations may similarly be connected with the fire-camp nearby. 



In general administration on forest reserves various kinds of temporary camps 

 are established, all of which may require telephone connection to attain the greatest 

 efficiency. Emergency lines will serve to provide such connection if a comprehensive 

 system of permanent lines has been installed. 



Section 62 Line Construction 

 1 LINE MATERIALS 



The wire adopted for emergency lines in forest protection is approximately a No. 

 20 B. & 'S. gauge consisting of 10 strands of No. 30 B. & S. gauge hard-drawn copper 

 wire twisted together and insulated with a double-reverse, close serving of cotton, 

 waterproofed with asphaltum compound. (For specifications see Appendix E.) It 

 has a resistance of about 53 ohms per mile or approximately the same as No. 14 

 B.W.G., BB., galvanized-iron wire. Its weight is 20 pounds per mile, and its breaking 

 strength 48 pounds. This wire is purchased in half-mile lengths wound on wooden 

 spools conforming to the standard specifications. (See Appendix E.) 



The only other line-construction materials required are some rolls of cotton tape 

 (stationers' red tape is good) or some balls of cotton package twine, and some 3-in. 

 wire nails. 



2 LINE TOOLS 



The crew employed in laying an emergency line requires the following tools and 

 material : 



1 2^-in. screw-driver 1 roll friction tape 



1 pair 6-in. side-cutting pliers 1 forked pole or crook-stick 



1 emergency wire reel 1 ball cotton twine 



1 pocket-knife for each man Supply of 3-in. wire nails. 



1 hand-axe for each man 



