CONTENTS xiii 



Fig. Page 



95 Receiver -test 148 



96 Ringer of No. 127^F extension bell and Nos. 1317-P, 1317^8, 300-N, and 1336-J 



-telephones 151 



97 Wiring of No. 1317 telephone set 153 



98 British Army type of heliograph, one-mirror 162 



99 British Army type of heliograph, two-mirror 16-3 



100 American Army type of heliograph, one-mirror 164 



101 American Army type of heliograph, two-mirror 164 



102 Forest Service type of heliograph, one-mirror 166 



103 Forest Service type of heliograph, two-mirror 167 



104 Map of California national forest showing heliograph system 168 



105 Forest ranger sending message by heliograph 171 



106 Acetylene signal lantern with tripod 183 



107 Fischer high-power electric signalling lamp 184 



1 108 Initial position in flag signalling 189 



109 " Dot " or (motion " 1 " in flag signalling 190 



110 " Dash " or motion " 2 " in flag signalling 190 



111 Semaphore alphabet, numerals, and special signs 192 



112 Two-arm fixed semaphore code 193 



Design of Forestry Branch standard pony glass insulator 214 



Design of Forestry Branch standard split tree insulator .. 215 



Design of Forestry Branch standard emergency wire spool 217 



Design of Forestry Branch standard wooden bracket 218 



Design of outdoor protector mounting-box 219 



