So the trains of munitions passed the trains laden with the products of war, the knowledge of whose sacrifice is the only value of war. Right and left through the intermediate zone, from Orléans to the Mediterranean, were more repair shops, remount depots, training camps for aviators, tank crews, machine-gunners and carrier pigeons, each worker striving for the same purpose that shoveled the coal into the locomotive firebox or slipped a shell into a gun or a cartridge into a rifle. At Is-sur-Tille, near Dijon, was another "hump," which looked down on what seemed a training camp in its streets of mud: for there was mud in the S. O. S. as well as at the front--mud kept soft by the damp atmosphere when autumn rain was not falling, and deep by the trampling of many feet. Here, as at Gièvres, the train sent its cars on their way to the warehouses to which their contents belonged; here you felt at first hand the breath of the front in all its hot and pressing demands; here was the largest bakery, with cement floors and all up-to-date apparatus, directed by the head of one of our large bakeries at home, rolling out the round loaves with the ease of peas shelled from a pod. All night long, as at Gièvres and at the base ports, the switch engines coughed forth their growls as they shunted cars, and the laborers worked at loading and unloading. The officer in charge in his little office was directing as insistent an excursion business as ever fell to the lot of man. His nightmare, and the nightmare of all the regulating officers of the S. O. S., was moving cars. Every hour a car was needlessly idle was waste. This called for labor, and more labor--for more warehouse space, for more locomotives, for more sidings; but as they were not forthcoming, why, man and machine must be made to do more work. The excess strain on either was not considered. The pressure was the same as that for the relief of a city stricken by fire or earthquake.