They spent all the night in the troop-train, which was crowded almost to suffocation. Where they were going they didn't know, scarcely cared. Sometimes they were drawn up to a siding where they would stay for hours, then the train crawled on again. Presently the morning broke and Tom saw a flat and what seemed to him, after Surrey, an uninteresting piece of country. Everything was strange to him, even the trees looked different from those he had seen in Surrey. On and on the train crawled, until presently they had orders to alight. It was now early morning, and after breakfast they were formed in marching order. Tom took but little notice of the country through which they marched, except that they were on a straight road, which was paved in the middle. As the day advanced the sun grew hot and scorching, but the men marched on uncomplainingly; there was little merriment, but much thought. Presently noon came, and again they stopped for food, after which there was another march. By this time Tom realised that he was indeed in the zone of war. He saw what looked to him miles of motor waggons filled with food and munitions, numbers of ambulance waggons marked with the Red Cross. More than one body of horse soldiers passed him, and again he saw numbers of men bivouacked near him; but everywhere there were soldiers, soldiers. Tom could not understand it, it was all so different from what he expected, neither could he see any order or purpose in that which was taking place around him. There was activity and movement everywhere, but he could co-ordinate nothing, he was simply bewildered. Towards evening there was another resting-time, and each man gladly threw himself full length on the grass. For a moment there was a silence, then Tom heard a sound which gave him a sickening sensation; he felt a sinking, too, at the pit of his stomach: it was the boom, boom, boom of guns. "Look at yon' airship in the sky!" cried one of the men. Each eye was turned towards it, then they heard the boom of guns again, after which there were sheets of fire around the aeroplane, and afterwards little clouds of smoke formed themselves. "I am getting near at last," thought Tom. "I wonder now--I wonder----" CHAPTER V Tom discovered presently that his destination was the Ypres salient, one of the most "unhealthy" places, to use the term in favour among the soldiers, in the whole of the English battle line. Here the most tremendous battle ever fought in our British Army took place--indeed one of the most tremendous battles in the history of the world. A sergeant who was in a garrulous mood described it to Tom with a great deal of spirit.