SIGNALLING WITH THE HELIOGRAPH 181 



Heliographs have only once been employed in forest protection in Canada. There 

 is no reason, however, why they would not be extremely useful. Suitable atmospheric 

 conditions prevail throughout the western forest regions, especially in Alberta and 

 the interior of British Columbia and during most of the summer throughout the 

 east and north. 



One ameliorating circumstance in connection with the impossibility of using the 

 heliograph except in full sunlight lies in the fact that with rain or overcast sky 

 the need for using it in connection with forest protection is likely to be very much 

 reduced. Successful utilization of this instrument, of course, requires the employ- 

 ment of interested and intelligent men and a higher degree of organization and 

 discipline in the protection staff than has heretofore been thought necessary. 



The learning of the alphabet can be taken up indoors by using an inexpensive 

 telegraph key and sounder installed with a telephone dry cell. Practice should be 

 continued until the letters, numerals, and conventional signals are thoroughly 

 mastered. 



The operators should then be practised on the heliograph itself and taught to set 

 up quickly and align accurately. Men can practise singly in maintaining alignment 

 and also in cultivating rhythmic sending "by directing the beam toward an ordinary 

 mirror set up at a distance of about 100 ft. and placed so that the flash is reflected 

 back to the sender. 



When the alphabet has been thoroughly learned and a good sending-speed devel- 

 oped, a practice range equipped with telephones should be installed. The distance 

 between said stations may be as long as conditions warrant but should, if possible, 

 be at least half a mile. If an existing telephone line cannot be tapped, a temporary 

 line may be built with emergency wire if available. On this range with two instru- 

 ments a number of men may be taught to receive messages, to send messages, and, 

 especially, they may be given practice in the various "tricks" of sending and receiving 

 that generally prove most difficult for beginners. The telephone serves to keep the 

 instructor in touch with both sets of men and enables him to correct mistakes of 

 sending with the least difficulty. 



For use at night or on dull days when the heliograph cannot be operated a couple 

 of signal-lanterns will be found highly convenient for instructional and practice 

 purposes. 



Section 116 Heliographing- by Moonlight and Artificial Light 



The heliograph ^ has been used to send messages by moonlight but the range is 

 extremely limited. It cannot be depended upon at any ordinary forest range. 



Artificial light may also be employed, the range depending on the strength of the 

 light. Only short ranges as a rule may be attained. When using an artificial light 

 with the fixed-flash heliographs it will generally be found more satisfactory to employ 

 the screen only, rather than attempt to reflect the light from the mirror. 



