But they were very cheerful. Officers with an hour to spare came up from the gunboats in the canal to smoke a pipe by the fire. Once in so often a woman came, stopping halfway her frozen journey to a soup kitchen or a railroad station, where she looked after wounded soldiers, to sit in the long room and thaw out; visiting officers from other parts of the front dropped in for a meal, sure of a welcome and a warm fire. As compared with the trenches, or even with the gunboats on the canal, the station represented cheer, warmth; even, after the working daylight hours, society. There were several buildings. Outside near the bridge was the wireless building, where an operator sat all the time with his receivers over his ears. Not far from the main group was the great hangar of the airship, and to that we went first. The hangar had been a machine shop with a travelling crane. It had been partially cleared but the crane still towered at one end. High above it, reached by a ladder, was a door. The young captain of the airship pointed up to it. "My apartments!" he said. "Do you mean to say that you sleep here?" I asked. For the building was bitterly cold; one end had been knocked out to admit the airship, and the wall had been replaced by great curtains of sailcloth to keep out the wind. "Of course," he replied. "I am always within call. There are sentries also to guard the ship. It would be very easy to put it out of commission." The construction of the great balloon was explained to me carefully. It was made of layer after layer of gold-beater's skin and contained two ballonets--a small ship compared to the Zeppelins, and non-rigid in type. Underneath the great cigar-shaped bag hangs an aluminum car which carries a crew of three men. The pilot sits in front at a wheel that resembles the driving wheel of an automobile. Just behind him is the observer, who also controls the wireless. The engineer is the third man. The wireless puzzled me. "Do you mean that when you go out on scouting expeditions you can communicate with the station here?" I asked. "It is quite possible. But when the airship goes out a wireless van accompanies it, following along the roads. Messages are picked up by the van and by a telephone connection sent to the various batteries." It may be well to mention again the airship chart system by which the entire region is numbered and lettered in small squares. Black lines drawn across the detail map of the neighbourhood divide it into lettered squares, A, B, C, and so forth, and these lettered squares are again subdivided into four small squares, 1, 2, 3, 4. Thus the direction B 4, or N 2, is a very specific one in directing the fire of a battery. "Did you accomplish much to-day?" I inquired. "Not as much as usual. There is a ground haze," replied Colonel M----, who had been the observer in that day's flight. "Down here it is not so noticeable, but from above it obscures everything."