and the world began to realize that all historic conditions of war had been revolutionized by the use of scientific weapons of destruction like the machine gun, which mowed down men like hay, and the high explosive shell that destroyed protective works as if they were made of cardboard and filled the trenches with dead and dying bodies.  Such was the situation on the western front in the beginning of December.  No let-up in the determination of either side; no advance seemingly possible, no attack that was not followed by a counter-attack; no gain of any consequence anywhere; no possibility seemingly of any decisive battle; nothing in sight but an absolute deadlock.

ON THE EASTERN FRONT.

Late in September the German campaign against Russia appeared to lose most of its force.  Continued attempts were made by Field Marshal von Hindenburg to fight his way to Riga, but without avail, and Russian successes at various points along the eastern battle front were numerous in October and November.  The Russians declared on November 15 that they deemed the city of Riga safe, and by November 26 it was apparent that the Germans were engaged in a general retirement all along the River Dvina.  The Allies then became interested in the Kaiser’s probable choice of a line of defense for the winter on the northern section of his Russian front.  The breakdown of the German offensive was attributed by the Allies to three things—­the increase in the Russian ammunition supply, a German shortage of munitions, and the weakening of the German line for the Balkan campaign.

BULGARIA ENTERS THE WAR.

On October 1, 1915, it was evident that Bulgarian forces would shortly be employed on the side of the central powers.  Bulgarian troops from Sofia were moving on to the Serbian frontier.  King Ferdinand had ordered the mobilization of all men under sixty-five years of age and martial law was proclaimed, no citizen under forty-five being allowed to leave the country.  On October 4 Russia sent an ultimatum to Bulgaria and the Russian minister was ordered to leave Sofia if by 4 p.m., October 5, Bulgaria did not definitely break with Germany, Austria and Turkey.  All the allied powers supported Russia in this demand.  Bulgaria did not reply within the time specified and the Russian minister was reported too ill to move from Sofia, thus indicating that the diplomats of the great contending powers were still at work in an effort to secure the important support of Bulgaria in the Balkan campaign which was imminent.

On October 6, when Bulgaria was said to have sent an ultimatum to Serbia demanding the territory ceded after the recent Balkan wars, the envoys of the Allies at Sofia requested their passports, and Bulgaria became an active participant in the war.  The Bulgarian minister at Nish, the Serbian capital, received his passports on October 8, and on the same day the Bulgarian minister at Paris was handed his passports.  On the following day, October 9, Belgrade, the former Serbian capital, was occupied by Austro-German forces and the invasion of Serbia by Austria and Germany from the north and by Bulgaria from the east began in earnest.  The Serbian capital was removed the same day to Ishtib, in the south.