Without petrol for lorries, tractors, motor-cars, aeroplanes--without heavy oil for ships' boilers and factory engines--without lubricating oil for all machinery, how was it possible to carry out the combined movements of armies? It was not until about 1916 that people began to say this War would be a "war of oil." The army staffs first grasped its real utility during the defence of Verdun, situated at the end of a wretched railway with a single line of metals. The destruction of many railway lines and the inadequacy of the system behind the front led the generals to transport their troops more and more frequently by motor-lorry. It might be said that this War was the victory of the lorry over the railway. The last phase, in particular, consisted in a campaign of motors and aeroplanes against railways. Rich in railway materials, our enemies were poor in petrol. Our High Command, at the end of 1918, resolved to profit by our superiority on this point. Before the War, Germany imported 1,263,000 tons of oil: 719,000 from the United States; 220,000 from Galicia; 158,000 from Russia; 114,000 from Rumania; 52,000 from India. From the very beginning of hostilities nearly all these sources were closed to her. That is why the German General Staff fought so hard for Galicia, then for Rumania, and finally for the Caucasus. "As Austria could not supply us with sufficient oil," wrote Ludendorff in his _Memoirs_, "and as all our efforts to increase production were unavailing, Rumanian oil was of decisive importance to us. But even with deliveries of Rumanian oil, the question of oil supplies still remained very serious, and caused us great difficulty, not only for the conduct of the War, but for the life of the country. The stocks of the Caucasus opened a more favourable prospect for us in 1918." "The eastward march of the central empires is thus explained as due to the urgent need for the conquest of oil. The treaty of Bukarest was an 'oil peace,' as also was that of Brest Litovsk. "In Rumania, Germany seized all the oil-deposits, all the refineries, all the pipe-lines, and altered and reorganized them according to the immediate needs of her armies. For the benefit of her dependent company, the _Steaua Romana_, she plundered all the properties of the British, Dutch, French, or purely Rumanian companies. "It was then that she destroyed the Baïkop-Constantza pipe-line and relaid the pipes on a military route from Ploesti to Giurgiu. It was then that the economic staff of her army founded in 1917-18 the _Erdol Industrie Anlagen Gesellschaft_, which sequestrated, liquidated, despoiled all the other oil companies and collected the booty for its own profit in a vast monopoly of exploitation and distribution. This monopoly was only broken in August 1918, by the double victories of the Allies on the Eastern and Western fronts."[14]