The Russian Offensive Also Steps Out 109 the French Army had made the definite statement, three years earlier, that between the twenty-first and twenty-third days after mobilization had been ordered Russian troops would be at the German frontier. German military writers had ridiculed this, declaring that six weeks was the minimum of time in which the Czar's forces could begin to be- come effective. Yet as the German armies were advancing through Brussels to their first victory on fields familiar to the students of the Waterloo campaign, their gen- erals received news of evil omen. Precisely as Na- poleon, at the moment he was launching his attack upon Wellington, learned of the appearance of Prus- sians in the fields toward Plancenolt, the German commanders at Charleroi heard that Russia had stepped over into East Prussia, had passed Gumbln- nen, won several victories. Isolated Koenlgsberg, and was driving forward toward the Vistula furiously. Evidently Russian mobilization had been quicker than was expected and at the end of the third week it was necessary to deplete the armies in France. Two corps had to be sent east while the first great battle was still unfought. The Russian offensive was naturally divided Into two parts, one directed against Austria, the other against Germany. The former was composed of at least twelve army corps based on Brest-LItow- ski, Lublin and Rowno; the latter, of perhaps fif- teen with the centre at Warsaw. To meet the twelve