Next the flight-commander made up his mind to bridge the chasm of difficult communication between pilot and observer. Formerly, in two-seaters with the pilot's seat in front, a message could only be delivered on a slip of paper or by shutting off the engine, so that one's voice could be heard; the loss of time in each case being ill afforded when Huns were near. An experiment with a wide speaking-tube, similar to those through which a waiter in a Soho restaurant demands _côtelettes milanèses_ from an underground kitchen, had proved that the engine's roar was too loud for distinct transmission by this means. We made a mouthpiece and a sound-box earpiece, and tried them on tubes of every make and thickness; but whenever the engine was at work the words sounded indistinct as words sung in English Opera. One day a speedometer behaved badly, and a mechanic was connecting a new length of the rubber pitot-tubing along which the air is sucked from a wingtip to operate the instrument. Struck with an idea, the pilot fitted mouthpiece and earpiece to a stray piece of the tubing, and took to the air with his observer. The pair conversed easily and pleasantly all the way to 10,000 feet. The problem was solved, and ever afterwards pilot and observer were able to warn and curse each other in mid-air without waste of time. The high-powered two-seaters of to-day are supplied with excellent speaking-tubes before they leave the factories; but we, who were the first to use a successful device of this kind on active service, owed its introduction to a chance idea. One by one our six war machines arrived and were allotted to their respective pilots. Each man treated his bus as if it were an only child. If another pilot were detailed to fly it the owner would watch the performance jealously, and lurid indeed was the subsequent talk if an outsider choked the carburettor, taxied the bus on the switch, or otherwise did something likely to reduce the efficiency of engine or aeroplane. On the whole, however, the period of waiting was dull, so that we welcomed comic relief provided by the affair of the Jabberwocks. The first three machines delivered from the Rafborough depôt disappointed us in one particular. The movable mounting for the observer's gun in the rear cockpit was a weird contraption like a giant catapult. It occupied a great deal of room, was stiff-moving, reduced the speed by about five miles an hour owing to head resistance, refused to be slewed round sideways for sighting at an angle, and constantly collided with the observer's head. We called it the Christmas Tree, the Heath Robinson, the Jabberwock, the Ruddy Limit, and names unprintable. The next three buses were fitted with Scarff mountings, which were as satisfactory as the Jabberwocks were unsatisfactory.