My uncle had bequeathed me both his work and his fortune, but despairing of my ability worthily to continue his own brilliant researches on synthetic food, I turned my attention to the potash problem, in which I had long been interested. My reading of early chemical works had given me a particular interest in the reclamation of the abandoned potash mines of Stassfurt. These mines, as any student of chemical history will know, were one of the richest properties of the old German state in the days before the endless war began and Germany became isolated from the rest of the world. The mines were captured by the World in the year 2020, and were profitably operated for a couple of decades. Meanwhile the German lines were forced many miles to the rear before the impregnable barrier of the Ray had halted the progress of the World Armies. A few years after the coming of the Ray defences, occurred what history records as "The Tragedy of the Mines." Six thousand workmen went down into the potash mines of Stassfurt one morning and never came up again. The miners' families in the neighbouring villages died like weevils in fumigated grain. The region became a valley of pestilence and death, and all life withered for miles around. Numerous governmental projects were launched for the recovery of the potash mines but all failed, and for one hundred and eleven years no man had penetrated those accursed shafts. Knowing these facts, I wasted no time in soliciting government aid for my project, but was content to secure a permit to attempt the recovery with private funds, with which my uncle's fortune supplied me in abundance. In April, 2151, I set up my laboratory on the edge of the area of death. I had never accepted the orthodox view as to the composition of the gas that issued from the Stassfurt mines. In a few months I was gratified to find my doubts confirmed. A short time after this I made a more unexpected and astonishing discovery. I found that this complex and hitherto misunderstood gas could, under the influence of certain high-frequency electrical discharges, be made to combine with explosive violence with the nitrogen of the atmosphere, leaving only a harmless residue. We wired the surrounding region for the electrical discharge and, with a vast explosion of weird purple flame, cleared the whole area of the century-old curse. Our laboratory was destroyed by the explosion. It was rebuilt nearer the mine shafts from which the gas still slowly issued. Again we set up our electrical machinery and dropped our cables into the shafts, this time clearing the air of the mines. A hasty exploration revealed the fact that but a single shaft had remained intact. A third time we prepared our electrical machinery. We let down a cable and succeeded in getting but a faint reaction at the bottom of the shaft. After several repeated clearings we risked descent.