If the armchair critic has read the above he will perhaps realize a little more vividly than he has done before how difficult advances are and why it is more easy to talk of getting the enemy on the run than to actually do it. Once he has started to retreat and you to advance, your difficulties multiply and go on increasing in direct proportion to the distance that you get from your base of supplies. Your munitions, food and water must be transported from the rear over strange roads pulverized by shell fire, while your enemy is backing into greater supplies hourly.
One of the most difficult propositions is to keep the different parts of your immense organization in communication with battalion, brigade, and divisional headquarters. Many different methods are used.
Perhaps the most reliable is by runner, or courier, on foot. The runner has an arduous, dangerous, and often thankless, task, which he performs as a rule patiently, bravely and tirelessly. The telephone, telegraph, and power buzzer--the latter being sometimes used without wires, at a distance as great as 4000 yards--are commonly employed, though they have many disadvantages. The first of these is the difficulty in installing them in the face of heavy shelling and counter attacks by the enemy. Secondly, they are likely to be put out of commission, their wires being destroyed by shells. Finally, their messages are often picked up through the earth by your opponents with some apparatus invented for the purpose.
There are the semaphore and flashlight methods of signaling, and signaling by flares, all naturally very limited in variety of use, the latter particularly so. But flares are of great service when a hurried artillery retaliation is desired, S.O.S. flares then being sent up. The wireless apparatus on aeroplanes and the throwing of flares by aviators are also used to good account. But there are times when all these different methods are found wanting. Through force of circumstance a battalion or company may be completely isolated, and then it is that the last and least employed method, that of carrier pigeons, is resorted to. In each battalion are a couple or more specially trained carrier pigeons, and to speak of the "O.C. Pigeons" is a standing joke. The pigeons are rarely employed. It may be almost forgotten that they are with a unit, as was practically the case of one battalion at the Somme of which the following story is told: