It was, of course, recognized from the very first that thorough acquaintance not only with every means of communication from the air to the ground, but also ability to read every signal necessarily transmitted from the ground to the air, was one of the most important requirements in the training of a pilot.

The ranging of guns (particularly heavies), the finding of targets and their destruction have all been successfully accomplished by coÖperation between the pilot and the communicating battery. Numberless devices have been experimentally tried such as coloured lights, signalling by lamps, etc., etc.; but none proved a means of communication which was not only reliable but which also afforded no invitation to attack by the enemy. As the outcome, the wireless system from the aeroplane to the ground, and ground strips, or panneau, from the ground to the aeroplane were adopted and uniformly used. As far as concerns the training work of the Canadian wing of the Royal Flying Corps, the methods used were naturally those already established in England.

On arrival at the Recruits’ Depot, the cadet received his first initiation, together with a small amount of instruction in the code used. Moving hence to the Cadet Wing at Long Branch, wireless formed a definite part of the routine of the day’s work. The cadet was required to successfully send and receive six words per minute, and for purposes of instruction telephones were connected to the buzzer circuits. In the tuition of sending, Morse recorders operated by means of a silenced key were installed, and picture targets, constructed with miniature lamps shining haphazardly through small holes, were operated from a switchboard. These represented shell bursts which the cadet was required instantly to locate and report.

With six weeks’ of wireless at the Cadet Wing, the pupil proceeded to the School of Aeronautics for further instruction, and heard lectures on picture target work and artillery coÖperation from experienced observers. Requirements now demanded eight words per minute. After examination, his next step was to the elementary training wing at either Deseronto or Borden, where he not only carried on ground work, but also put into actual practice in the air the instruction already received.

Moving on to North Toronto he reached the stage of final tuition in this section of his course. At varying distances from this station, puff targets were provided to simulate shell bursts, and the embryo pilot conducted himself as though on active service by locating the shoot and reporting it with necessary adjustments to the battery receiving station. Such was the value attached to this phase of training, that eighty per cent. of the observations sent down were required to be correct before the pupil was considered passed. The tests included reading ground messages, bomb dropping, etc., the latter being checked by a camera obscura hut which was used as the target. In this process it was necessary that the cadet adjust his bomb sights both for the speed and altitude of his machine. This being done, his wireless key was depressed and the actual position of his machine recorded in the camera obscura hut at the moment of signalling, which moment, it was understood, was the instant at which the bomb would have been dropped were the machine in actual service. The result recorded infallibly the amount of judgment which had been used. Some idea of the extent of this School may be gathered from the fact that a tour around the batteries involved a 60 mile trip. Bomb-dropping, though having no connection with artillery observation, was here practised as a matter of convenience.

If it be asked why the pilot does not receive as well as send wireless messages while in the air, it may be stated that up to the present the difficulties of receiving on a trailing aerial have been such that what might be termed a graphic ground method has proved preferable. Large ground strips are, on active service, an invitation for bombardment by the enemy and are being aided by the Popham Panneau, a method of signalling consisting of the rapid forming up of small, symmetrical, rectangular figures, by arrangements of white bands capable of rapid variation. In general they are the combination of the letter “T” with short, symmetrical additions.

The Aldis lamp, also used, is an improvement on the heliograph, and reflects the rays of an electric globe instead of sunlight, but it will be understood that recent advances in wireless telephoning have revolutionized the above methods.

A word is in place with regard to the Artillery CoÖperation School at Leaside through which all pilots of necessity must pass. The equipment is the result of very brilliant work by an R.A.F. officer. The maps themselves represent two sections of the Western front, and are reproduced with vivid accuracy from aerial photographs. Each is 40 feet × 20 feet, and contains some eighty targets so arranged as to allow switching from one gun pit to another, thus following the actual work of destruction by imaginary batteries. Zone calls are arranged for all targets, these representing every possible point for bombardment, such as hostile battery positions, trench points, railroads, cross roads and fortified positions in enemy towns. British and German trenches are shown on a scale of approximately five inches to one hundred yards.

The total number of electric globes used to simulate bursts is 1,360, and the two balconies where the observing pilots sit are so equipped that every operation which must be carried out in doing wireless tests must be completed before signals can be received by the operator seated below at the imaginary battery. Space does not permit of a detailed description of the intricate, electrical work required to complete this admirable installation. It suffices to say that those best qualified to judge deem it a very considerable achievement.

Rotary targets are also used, as by turning them practically the same condition is created as that which confronts the pilot when turning his machine in the air. These, too, represent a reproduction of well-known sections of the Western front.

A special map was devised for contact patrol work, presenting three distinct lines of trenches together with an equal number of groups of headquarters, as well as machine gun pits, tanks, etc., while wireless sending was coupled up with Aldis lamp work—the latter requiring to be read at four words per minute.

At the conclusion of instruction of every course it was demanded that every cadet both receive and send at a speed of eight words per minute before being allowed to proceed with aerial tests.