“Now you’ll see something,” cried Astor with tightening lips as he scanned the battlefield. “It may come at any moment. We’ve got them where we want them. Thousands and thousands of them! Their whole army!” He pointed to the pontoon bridges where the last companies of the German host were crossing. On the heights beyond, their artillery fire was slackening; and on our side the American fire had ceased. Night was falling and the Germans were evidently planning to encamp where they were. “There are a few thousand over there with the artillery who haven’t crossed yet,” said I. “The Crown Prince must be there with his generals.” My friend nodded grimly. “We’ll attend to them later. Ah! Now look! It’s coming!” I turned and saw a thick wall of grey and black smoke rolling in dense billows over a section of the rear trenches, and out of this leaped tongues of blue fire and red fire. And farther down the lines I saw similar sections of smoke and flame with open spaces between, but these spaces closed up swiftly until presently the fire wall was continuous over the whole extent of the rear trenches. We could see German soldiers by hundreds rushing back from this peril; but, as they ran, fires started at dozens of points before them in the network of ditches and, spreading with incredible rapidity, formed flaming barriers that shut off the ways of escape. Within a few minutes the whole area beneath us, miles in length and width, that had been occupied by the victorious German army, was like a great gridiron of fire or like a city with streets and avenues and broad diagonals of fire. All the trenches and ditches suddenly belched forth waves of black smoke with blue and red flames darting through them, and fiercest of all burned the fire walls close to the river bank. “Good God!” I cried, astounded at this vast conflagration. “What is it that’s burning?” “Oil,” said Astor. “The whole supply from the Standard Oil pipe lines diverted here, millions and millions of gallons. It’s driven by big pumps through mains and pipes and reservoirs, buried deep. It’s spurting from a hundred outlets. Nothing can put it out. Look! The river is on fire!” I did look, but I will not tell what I saw nor describe the horrors of the ensuing hour. By nine o’clock it was all over. The last word in frightfulness had been spoken and the despoilers of Belgium were the victims. I learned later that the pipes which carried these floods of oil carried also considerable quantities of arseniuretted hydrogen. The blue flames that Mr. Astor and I noticed came from the fierce burning of this arseniuretted hydrogen as it hissed from oil vents in the trenches under the drive of powerful pumps. Thousands of those that escaped from the fire area and tried to cross back on the pontoons were caught and destroyed, a-midstream, by fire floods that roared down the oil-spread Susquehanna. And about 7,000 that escaped at the sides were made prisoners.