The great military interest of these arrangements must not detain us. Their publication reveals the fact, long unknown save to a few, that Joffre not merely hoped for, but definitely planned, a resumption of the offensive from a line midway between the Sambre and the Marne, that is, from the natural barrier of the Somme and the St. Gobain–Laon hills. We shall see that an effort was made to carry out these dispositions, and that it failed. The failure was lamentable, inasmuch as it doomed another large tract of country to the penalties of invasion. But, because the dispositions ordered on August 25 were only provisional details, not essentials, of the new plan, the military result was in no way compromised. While dealing with local emergencies or opportunities, Joffre envisaged steadily the whole national situation. The essentials of the “General Instruction” of August 25 were four in number: (_a_) a defensive stand by the armies of Alsace and Lorraine, and a provisional defensive by the two armies next westward, the 3rd and 4th; (_b_) a strictly controlled continuation of the northern retreat while reorganisation took place and forces were transferred from the east to the north-west; (_c_) an ultimate offensive initiated by the western and central armies, of which one additional, to be called the 9th, under General Foch, about to be interjected between the 4th and 5th, is not yet mentioned; (_d_) the constitution of a new left wing, to meet the extraordinary strength of the German right, and to attempt a counter-envelopment. The Amiens–Laon line fell out of the plan; the plan itself remained, and it is fully true to say that in it lies the germ of the battle of the Marne. III. BATTLE OF THE GAP OF CHARMES Everything was conditional upon the defence of the eastern frontier, now at its most critical phase.[32]