Early Days in the Forest Service Volume 4

THE FOREST SERVICE HELIOGRAPH
By E. Clayton McCarty

Use of the heliograph as a means of communication in the Forest Service caused argument and talk, both for and against. But before telephones, mankind had very little choice throughout the centuries of ways to get messages over distances greater than his own voice could reach. A messenger could be sent on foot or on horseback, requiring hours or many days to deliver his message. Hand signals or flags could be used by parties close enough to maintain direct sight of each other. For any greater distance there was left only fire, smoke, or flashes from the sun.

Since speed was extremely important in reporting, assembling a crew, and getting it on to any fire in the remote areas of western forests before it burned beyond hope for control, the heliograph was the only practical means available to the Forest Service in its earlier days. Its flash could carry fifty miles or more in clear air, and its message could be delivered in a matter of a few minutes, which meant a fire crew could be working on a new fire many days earlier.

But the heliograph was a tricky instrument for the untrained person. It meant the sun must be shining. It meant controlling and directing those sun flashes. It meant knowing and using a complicated code, and many-men found the heliograph hard to use and frustrating.

In my own experience in the Northern Region (1917-1920) things worked out well enough so that I actually learned some camp cookery by heliograph. It was on the Clearwater National Forest. I was a high school student at the time, and green. So I could not cook too well. Many days I'd ask Osier Ridge Lookout by heliograph how to boil water or bake bread or mix up some sort of goulash. Osier would get instructions by phone from the cook at Fish Lake Ranger Station, then flash them to me on Blacklead. There were gaps in the messages, but I usually caught enough to cook up the messes.

I remember there were two types of heliographs left for me to use on Blacklead. One consisted of two tall tripods that could be extended somewhere near shoulder height. I am not certain whether the two mirrors and sighting device were on one tripod and the shutter on the other, but I believe that was the arrangement.

The other instrument I used was a smaller portable heliograph, with both mirrors, sight, and shutter all on one tripod which opened out to an elevation somewhere near thirty inches above ground level. It was my favorite.

But anyway, the essential parts of either heliograph consisted of the main mirror, which actually flashed the signal to the other station, a straight arm which held this mirror at the rear, and a sight somewhat like the front sight on a rifle near the front end of the straight arm. This main mirror was adjustable in all directions and had a tiny hole in its exact center.

You used the tiny hole as you would use the back sight of a gun. You looked through it, with the shutter open. You sighted through it to the front sight and lined the straight arm exactly on the receiving station as if it were a rifle. Then you locked it in position.

Next you closed the shutter and focused the sun on the shutter by means of the main mirror. This made a shadow of the front sight on the shutter. Also, the tiny hole in the main mirror appeared as a small shadow dot on the shutter. The trick was to adjust the mirror so that the dot shadow rested exactly on the tip of the front sight's shadow. Any flash then would go directly toward the receiving station.

This was easy when the sun shone directly in front of the instrument or only a few degrees to the side. When the sun got too far overhead, or to one side, or in back of the main mirror, you had to catch the light first on the second mirror. This meant, of course, that the second mirror was not only adjustable in all directions, but that it must be mounted on an auxiliary arm fastened to the tripod to catch the sun from any angle. The arm could be rotated about the tripod. Then this second mirror would focus sunlight on the main mirror. From there it went through the shutter in the regular manner. Sighting of the main mirror was the same when the second mirror had to be used.

The smaller portable instrument seemed to me to be the most practical and most simple to set up and use. Its flash carried easily from Blacklead to Osier Ridge Lookout, and sometimes their answering flash seemed to my eyes to cover the whole Osier Ridge, almost blinding on a good day. I imagine mine looked the same from Osier.

There was one slight problem on the smaller heliograph. If you snapped the shutter open and closed too violently it tended to throw the instrument out of line, and, of course, the flash would no longer be seen from Osier. Very careful and gentle opening and closing made it unnecessary to re-sight the instrument, though.

The main problem I had was keeping the sun focused exactly right on the shutter. As the sun moved, the shadow dot would crawl away from the tip of the front sight's shadow. So, I had to use my thumbscrews after every few words to center the dot again on the front sight shadow tip. Just a quarter of an inch off would interfere with communication. The operation became automatic with me — open and close the shutter to spell out a word or two, twist thumbscrew to re-center the dot, send several more letters, adjust the thumbscrew — over and over.

It took a bit of patience and, with relatively inexperienced people, sending or trying to read code from the other station was tedious, obviously. Even a short message took time. An experienced code man could have worked faster, of course.

There was one other problem also. The sun's movement took its reflection on the second mirror out of line with the main sending mirror and dimmed the flash, so it had to be adjusted periodically, although not as often as the sending mirror's dot on the shutter.

I think maybe these constant small adjustments made the men hate to use the heliographs, but it wasn't too hard to keep them in mind. And the Forest Service's own simplified code made it much easier to master the letters, even though you still had to keep part of your mind on both problems of signaling and adjustment at the same time.

Fortunately we had only one fire to report in Blacklead's area that summer, if I remember correctly, and it burned itself out in one stump the lightning struck. Maybe we'd have had some trouble with trying to get alidade bearing numbers across if that had been a bad fire summer. I did try to spot some that got started in the territory toward Moose and Osier, and we somehow seemed to have more trouble with numbers than with letters — our own lack of experience, I'm sure. I never knew whether any bearings I sent helped in triangulation for pin-pointing any of their fires. I don't think either Osier or I ever got a message through without a lot of repetitions, but that was because neither of us were experienced signalmen. Once I think we tried to focus on bonfires as an experiment at sending a signal at night, but only got faint glimmers. I've been told that it can be done.

I think the main problems of those who tried to use the heliograph for Forest Service communication were due to inexperience rather than to the instrument itself. It takes many months of hard work and practice to be able to send and receive code with any ease at all. Anyone without that experience would probably need to check himself on every letter he sent. And in receiving from the other station it would be easy to make mistakes in the number and duration of flashes and pauses when your mind and eyes were twisting from the code sheet to the flashes coming in.

Even with a couple of years of weekends here and there practicing signaling with flags in the Boy Scout troop I belonged to did not make me able to come anywhere near the skill needed to get a message across without mistakes and repetitions. The professionals on ship-board, in the navy, send and receive extremely fast — with lights, of course, which do not have the added factor of keeping up with sun movements with the focusing screws. For an amateur, to use the heliograph would take plenty of patience. I know, because I was one of those amateurs.

I think I mentioned to you the IWW smokechaser on Blacklead who called it a toy; and because of my age, I suppose, assumed I was simply playing like a kid. He threatened me with a knife several times to make me put up my instrument when he caught me trying to make my report to Osier. He went into rages at times that made me afraid he'd smash the heliograph.

The other interesting incident of that summer connected with my heliograph moments was more fun. A coyote began to come out of the trees down a bit below me every time I got the heliograph out. He always sat up, almost like a dog, and watched me until I finished and started to pack up. Then he would trot back into the woods. I never saw an animal so curious.

The heliograph was fun, but I will confess that I was glad when they sent me to Moose for my second summer and I could use the phone.