During the afternoon the Engineers of the 36th Division had taken over from the XVIII. Corps the destruction of bridges in Ham and along the river and canal to Ollézy. They were all effectively destroyed, save the main railway bridge at Pithon, which was found not to have been prepared. French railway troops, working in haste and with insufficient explosives, did all the damage in their power to it, but it is believed to have been swiftly repaired by the enemy. [Illustration: Map V. The Position before the German Attack, March 21st, 1918.] The battle had been till now an attack with great superiority of numbers upon partially-prepared positions, or naturally formidable obstacles, such as the canals and the marshy bed of the Somme. From the morning of the 23rd open warfare developed, from the moment the enemy, as happened early, had driven the 14th Division back from the Canal de St. Quentin at Jussy. That accomplished, the Canal de la Somme at this point formed no real obstacle to the German advance, because, from St. Simon to Voyennes, it was parallel with it. For the 36th Division there were no more defences till the front line of 1916 was reached. It had to fight its battle of the 23rd and 24th of March in open country. The account of that battle and of the remainder of the retreat must occupy a chapter to itself. FOOTNOTES: [48] Map V. [49] Lord Haig's Despatches. [50] Map VI. [51] Four of the six batteries of this Group moved on the night of the 20th. It is reported that their evacuated positions were assailed with destructive fire so heavy that they would have been completely neutralized from the first had they remained in them. CHAPTER XI THE GERMAN OFFENSIVE ON THE SOMME (II): MARCH 23RD TO 30TH, 1918