German ingenuity and barbarity were shown in two new forms of warfare introduced during this year.  Poison gas was first used, contrary to the terms of the Hague Conventions, against the Allied line on April 22, 1915.  It brought on the most horrible forms of suffering and torture, and compelled a temporary withdrawal of the French and English from trenches near Ypres (eepr).  Later, masks were used as a preventive of gas poisoning.  Eventually the Allies were forced to adopt the use of poisonous gases in bombs and shells in order to fight the Germans with their own weapon.  The other innovation was the “flame-thrower,” an apparatus which threw a flame of burning liquid or gas far ahead of the troops.  This has never been widely used by the Germans, because it proved almost as dangerous to themselves as it was to their opponents.  A sharpshooter’s bullet or a piece of shell might pierce the apparatus and the containers and produce dangerous results among the Germans.

THE GALLIPOLI CAMPAIGN.—­In the east the year opened with an attempt on the part of the Allies to force the Dardanelles with their fleets and take possession of the city of Constantinople.  The campaign gets its name from the peninsula of Gallip’oli, the European shore of the Dardanelles.  In February the campaign opened with a naval attack.  The Turkish fortifications, however, were strong enough to defeat a purely naval attempt and the Allied fleets met with heavy losses.  It has been stated since that had the Allies continued the attack one more day the Turks would have had to yield, as their ammunition was nearly exhausted.  In April troops were landed on the peninsula to aid in the attack.  The landing was accomplished at a terrible cost of life.  Siege operations were then begun against the Turkish and German forces defending the peninsula.  Month after month the fighting continued, but nothing worth while was accomplished.  Finally, in January of the next year, the campaign was abandoned.  It had cost the Allies heavily in money and lives, and its failure had lost to them the respect of the hesitating nations of southeastern Europe, Bulgaria and Greece.

THE WAR ON THE RUSSIAN BORDER.—­Along the Russian frontier also the Allied cause met with serious reverses.  The year had opened favorably with the Russians in control of most of Galicia.  In March the great Galician fortress of Przemysl, which had successfully withstood the attacks of the Russians the previous autumn, was compelled to surrender.

Meanwhile, in January, Russia once more attempted to carry out the other part of her general plan, the invasion of East Prussia.  The Russian troops succeeded as before in entering the coveted territory, this time crossing the troublesome lake region while the waters were frozen.  Soon, however, the invaders met with a decisive defeat.  In the Battle of the Mazurian Lakes, General Von Hindenburg took 100,000 Russian prisoners; the number of killed and wounded Russian soldiers is said to have been 150,000.  The Russians hurriedly retreated from German soil.