mirrors aro placed on tho mirror "bar and through the ar- 

 rangement for horizontal and perpendicular adjustment it is 

 G simple matt or to "bring thorn into adjustment with tho sun 

 and to align tho ray of light with the receiving station. 

 The message is transmitted "by e, serios of flashes made "by 

 tho opening and closing of the shutter which is set up in 

 tho direct ray of light. 



Tho Meyer code, "based ona system of ones and twos, 

 has "boon adopted as a standard codo "by the IT. S, Signal 

 Corps. Tho impression that tho Morse telegraph code is 

 used in connection with heliographs is erroneous. 



My first conception of this plan of communication 

 was secured through roading Mr. Graves 1 "book on fire pro- 

 tection. I finally succeeded in securing from tho District 

 Office two instruments with which I experimented personally. 

 Having satisfied mysolf that tho scheme was practicable I 

 secured six more and sent them out on to tho Forest. At 

 tho saino time I secured tho services of men who had served 

 in tho Signal Corps of tho army. Those men raoro sent out 

 to tho rangors 1 camps and stayed with them two or three 

 weeks, drilling them in tho use of tho machine. Although 

 tho men were of the average type of mountaineer, they very 

 cniiclrly memorized the code and -learned to operate the in- 

 strument. They wore then placed on tho lookout points. 



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