The German armies, following the Great Retreat from the Marne to the Aisne, and after the series of mighty struggles which make up the Battle of the Aisne, and the attempts to win the Channel ports, continued the efforts to break through the British and French lines. The British held the strong line of Ypres, and in March made gains at Neuve Chapelle. In April the Germans made a desperate effort to break through at Ypres. There followed the Second Battle of Ypres, terrific in itself, but especially notable because of the first employment by the Germans of poisonous gas. GAS: SECOND BATTLE OF YPRES COL. E. D. SWINTON [Sidenote: Second Battle of Ypres.] Since the last summary there has been a sudden development in the situation on our front, and very heavy fighting has taken place to the north and northeast of Ypres, which can be said to have assumed the importance of a second battle for that town. With the aid of a method of warfare up to now never employed by nations sufficiently civilized to consider themselves bound by international agreements solemnly ratified by themselves, and favored by the atmospheric conditions, the Germans have put into effect an attack which they have evidently contemplated and prepared for some time. Before the battle began our line in this quarter ran from the cross-roads at Broodseinde, east of Zonnebeke on the Ypres-Moorslede Road to the cross-roads half a mile north of St. Julien, on the Ypres-Poelcapelle Road, roughly following the crest of what is known as the Grafenstafel Ridge. The French prolonged the line west of the Ypres-Poelcapelle Road, whence their trenches ran around the north of Langemarck to Steenstraate on the Yperlee Canal. The area covered by the initial attack is that between the canal and the Ypres-Poelcapelle Road, though it was afterward extended to the west of the canal and to the east of the road. [Sidenote: Germans plan a gas attack.] An effort on the part of the Germans in this direction was not unexpected, since movements of troops and transport behind their front line had been detected for some days. Its peculiar and novel nature, however, was a surprise which was largely responsible for the measure of success achieved. Taking advantage of the fact that at this season of the year the wind not infrequently blows from the north, they secretly brought up apparatus for emitting asphyxiating vapor or gas, and distributed it along the section of their front line opposite that of our allies, west of Langemarck, which faced almost due north. Their plan was to make a sudden onslaught southwestward, which, if successful, might enable them to gain the crossings on the canal south of Bixschoote and place them well behind the British left in a position to threaten Ypres.