Chapter 38

WIGWAGGING AND HELIOGRAPHING.

Our tramp adventure was really quite a blessing to us, for it taught us the necessity of a good signaling system between the Goblins' Platform and the island and led to our learning how to wigwag, and later to the construction of a heliograph. Uncle Ed, when he read of our experience, sent us the U. S. Army "Manual of Signaling." Fred, the tailor of our camp, made us two white flags with red centers. Each flag was two feet square and was fastened to a light staff about five feet long. Then we got out the manual and practised sending signals, at first within shouting distance, until we got to be quite expert.

WIGWAG SIGNALS.

There were only three different movements that could be made with flags, but in the book different combinations of these movements were given to represent each letter of the alphabet and the numbers from 1 to 0. All these movements were begun and ended by holding the flagstaff upright, directly in front of the body, as shown in Fig. 147. The first movement was to swing the flag down to the right and back (Fig. 148), the second to the left and back (Fig. 149), and the third forward and back (Fig. 150). The following table gives the different combinations used for various letters:

The Wigwag Alphabet.

A 22 J 1122 S 212 B 2112 K 2121 T 2 C 121 L 221 U 112 D 222 M 1221 V 1222 E 12 N 11 W 1121 F 2221 O 21 X 2122 G 2211 P 1212 Y 111 H 122 Q 1211 Z 2222 I 1 R 211 tion 1112

Numerals.

1 1111 4 2221 8 2111 2 2222 5 1122 9 1221 3 1112 6 2211 0 2112 7 1222

The numbers 1, 2 and 3 indicate respectively the first, second and third movements. For instance, A was represented by the combination 22, which means that the flag must be swept to the left and back twice. B is represented by the combination 2112, that is, a sweep to the left, two sweeps to the right and a final sweep to the left, as shown in Fig. 151. The end of a word was represented by a sweep forward and back; the end of a sentence by two sweeps forward and back, and the end of a message by three sweeps forward and back. It will be noticed that the same combinations are used for 2 and Z, 3 and _tion_, 4 and F, 5 and J, 6 and G, 7 and V, 9 and M, and 0 and B. The following abbreviations were given in the Manual:

Abbreviations.

a after n not ur your b before r are w word c can t the wi with h have u you y yes

These abbreviations saved a lot of time, for when we wanted to signal the word _after_ instead of spelling it out--22-2221-2-12-211-3--we used the signal for A--22--followed by 3 to signify that it was the end of the word. Before was represented by 2112-3, _your_ by 111-211-3, etc. It took quite a little practice to learn the different combinations. Fred and Reddy soon became experts, and could flash the signals back and forth at a great rate.

WIGWAGGING AT NIGHT.

At night we used a torch in place of a flag. The torch consisted of a roll of dried birch bark tied with wire to the end of a staff. It was found necessary to place another torch on the ground directly in front of the signaler so as to fix a central point and enable one to determine whether the moving torch was swung to the left or right. A later improvement was to use three lanterns, one in each hand and one attached to the waist to fix the central position. It was quite an advantage to have a lantern in each hand, for it saved changing over from one to the other when a second movement followed a first or a first movement a second.

THE HELIOGRAPH.

The book that Uncle Ed sent us had in it a description of a heliograph, that is, an instrument for sending signals with flashes of sunlight. Although our wigwagging system was good enough for our requirements, yet we thought it would be more scientific to use the sun instrument, and besides, the latter could be used for signaling many miles.

THE SINGLE MIRROR INSTRUMENT.

The first thing we did was to procure a small mirror about 4 inches square, mounted in a wooden frame. Then we got a pair of small square head bolts about 1/4 of an inch in diameter and 1 inch long, also two strips of brass 1/2 inch wide and 3 inches long. In the center of each brass strip we drilled a hole just large enough to admit the shank of one of the bolts, and then the strips were fastened with screws tight against opposite edges of the mirror frame, with the heads pressed against the frame and the shanks sticking out at each side, as shown in Fig. 153. These projecting shanks served as "trunnions" (that is, pivots) for the mirror to turn on when it was mounted in place. After the trunnions had been set in place we made a peep hole in the center of the mirror by cutting out a piece of the wooden back of the frame and scratching away the silver from the back of the glass. Only a very small hole was required, about 1/8 inch in diameter. Great care was taken to have the unsilvered spot exactly on a line with the trunnions and just half-way between them. This done, we took two sticks of 3/8-inch wood, 1 inch wide and 3-1/2 inches long. In the upper end of each stick a slot was cut 1/2 inch deep and 1/4 inch wide. Into these slots the trunnions of the mirror were placed, and then the nuts were screwed tightly on, clamping the sticks against the sides of the mirror. The sticks were now connected by nailing a 1/2-inch strip at the bottom, and braced by a couple of corner pieces. This formed a swiveled frame for the mirror, which was clamped to the base of the instrument by means of a bolt 1-1/2 inches long. The bolt passed through the bottom board of the frame, squarely under the peep hole of the mirror and through the baseboard of the instrument near one end. The baseboard was 2 inches wide, 10 inches long and 3/4 inch thick.

THE SIGHT ROD.

At the end opposite to where the mirror frame was swiveled we mounted a sight rod, which was merely a round stick of wood 1/2 inch in diameter and about 8 inches long. We cut the stick from one of the rounds of an old broken chair. The upper end of the rod was whittled to a point and one side was flattened as shown in Fig. 155. Out of a piece of heavy white cardboard we cut a round disk about 1/4 inch in diameter, with a shank 1 inch long sticking out at one side. This was fastened with a single tack to the flattened end of the rod in such a position that the point lay exactly against the center of the disk. The disk could then be turned up or down, to cover or uncover the point of the rod, as desired. The rod was fitted snugly into a hole in the baseboard, and could be raised or lowered to any extent desired, but we had to provide some sort of an arrangement for making it stay where it was put. A small hole was drilled from the edge of the baseboard through to the hole in which the rod was fitted. A square socket was chiseled out around the small hole to receive a nut. The nut was firmly wedged in and held in place by driving in nails along the edges. A bolt or machine screw was threaded through the nut, so that its inner end pressed against the sighting rod. By tightening this screw the rod could be secured at any height desired.

The instrument was mounted on a tripod similar to the one used for our surveying instrument. To this it was attached by means of a bolt, which passed through the center of the baseboard and the tripod head.

THE SCREEN.

The screen, or shutter, of the heliograph was mounted on a separate tripod, so as to prevent shaking the mirror when it was operated. It was made something like a window shutter. We cut out two slats, each 2-1/2 inches wide and 6 inches long. They were made of hardwood 3/8 inch thick. The upper and lower edges were tapered down to a thickness of 3/16 inch. Light nails were driven into the slats at the ends, and the nail heads were then filed off so that the projecting ends formed trunnions for the slats to turn on. The slats were linked to a connecting rod with double point tacks. A small double point tack was driven into the upper edge of each slat about 1/2 inch from the right hand end. Then through each of these tacks we hooked a second double point tack and drove it into the rod. The tacks on the rod were placed just 2 inches apart. A substantial frame was then made of 3/4-inch stuff 1-1/2 inches wide. The frame was square, with an opening that measured 6 inches each way, into which the slats were fitted. Before nailing the frame together we drilled holes in the side pieces for the trunnions of the slats to turn in. These holes were just 1-3/4 inches apart. After the slats had been set in place, the frame was fastened together and then nailed to a baseboard, which was fastened by a bolt to the tripod. The shutter was operated by a key something like a telegraph key. It was made of a narrow stick of wood hinged at one end to the lower strip of the shutter frame, and a spool sawed in two was fastened to the other end to serve as a handle for the key. A string connected the key with the connecting rod. The slats were kept closed by a spring, which was fastened at one end to the connecting rod and at the other to the top of the frame. At first we used a rubber band for this purpose, but it soon wore out, so we then made a spiral spring out of stiff spring brass wire by wrapping it around a pencil. When the key was pressed down the slats would be turned open, as shown in Fig. 159; but as soon as the key was released the spring would pull them back again.

FOCUSING THE INSTRUMENT.

We were now ready to commence operations with our instruments. The heliograph was set up on the ledge at the top of the cliff. First the disk was turned down, uncovering the point of the sighting rod. Then Bill sighted through the unsilvered spot in the mirror and shifted the rod up and down until the tip end came squarely in line with the door of our straw hut, where Jack was seated, notebook in hand, to take down our message. Reddy stood by him with his wigwag flag to answer back. When the instrument was properly sighted the shutter was set up directly in front of it and the sighting disk turned up to cover the point of the sighting rod. Then came the rather troublesome task of focusing the mirror. The mirror reflected a square panel of light, in the center of which there was a small shadow spot made by the unsilvered peep hole. The object was to get this shadow to fall on the center of the sighting disk. We knew that then the mirror would reflect the sunlight squarely on the straw hut. We found it quite easy to direct this shadow spot to the disk by holding a sheet of paper in front of the mirror six or eight inches away, and following up the spot on the paper until it reached the disk.

HELIOGRAPH SIGNALING.

When at last we succeeded in properly focusing the mirror Bill pressed the key down three times, sending three quick flashes to Jack as a signal that he was ready to begin. Reddy wigwagged back O. K., and then the first heliographic message was sent from the ledge to the island. It was a rather mixed-up message, and kept Jim and Reddy wigwagging back and forth very strenuously to straighten matters out. It was my duty to keep the mirror focused. As the sun moved across the sky the shadow spot would move off the disk, and I had to keep shifting the mirror to bring the spot back where it belonged. We used the International Telegraph Code, which we had been studying every evening for a week, but it was many weeks before we learned how to use it correctly, even slowly. The International Telegraph Code is as follows:

A и- B -иии C -и-и D -ии E и F ии-и G --и H ииии I ии J и--- K -и- L и-ии M -- N -и O --- P и--и Q --и- R и-и S иии T - U ии- V иии- W и-- X -ии- Y -и-- Z --ии 1 и---- 2 ии--- 3 иии-- 4 ииии- 5 иииии 6 -ииии 7 --иии 8 ---ии 9 ----и 0 -----

The three short flashes Bill sent represented the letter S, which stood for the word "signal." A was formed by a short flash followed by a long flash; B by a long flash followed by three short ones, and so on. The key was held down three times as long for the long flash as for the short one. We found the best way of learning to send the signals properly was to count 1 for each short flash, and for each pause between parts of the letter, and 3 for each dash and for each pause between letters. Between words we counted 6. Thus, for the letter A the key would be down when we counted 1, up when we counted 2, down while we counted 3, 4, 5, and up while we counted 6, 7, 8, for the pause after each letter. It was rather a confusing code, I admit, but in time we mastered it, all but Reddy and Fred, who never would learn, but instead used the wigwag code, letting a short flash stand for 1, a long flash for 2 and a double long flash for 3.

THE DOUBLE MIRROR INSTRUMENT.

Our heliographing instrument did excellent service sending flashes from the cliff to the island, but we couldn't make it work very well sending messages from the island to the cliff, because we had to face almost due north, and then the sun was nearly always at our backs and couldn't shine squarely on the mirror. This led to our building a double mirrored heliograph the following summer. To begin with, we built an instrument which was the exact duplicate of our first heliograph; then, in addition, to fit in the socket of the sighting rod, we rigged up a second mirror, which was mounted in exactly the same way as the first. The second mirror was called the station mirror, and differed from the other, or sun mirror, in having a small patch of white paper pasted at the center instead of a peep hole. When using this instrument, we set it up so that the station mirror faced the ledge, then by sighting through the hole in the sun mirror at the reflection in the station mirror we could see just what was in focus. The station mirror had to be moved until the patch at its center hid the ledge from view. After that the sun mirror was shifted until the shadow spot fell on the white patch of the station mirror. When once the station mirror was focused, it could be clamped tightly in place by screwing up the trunnion and swivel nuts. But the sun mirror had to be constantly shifted to keep the shadow on the patch. Another way of focusing the mirrors was to stand behind the instrument with the head close to the station mirror, shift the sun mirror until the entire station mirror was reflected in it, with the white patch squarely over the unsilvered spot; then still looking at the sun mirror, the station mirror was shifted until the reflection of the distant station was brought squarely in line with the unsilvered spot on the mirror. The station mirror was now firmly bolted and the sun mirror adjusted until the shadow spot fell on the paper patch.