But at last I reached the rim!
I climbed out upon the flat plateau to the east of the abyss, a strange wilderness of green plains and purple trees, but infinitely welcome after the tortures through which I had been. I stumbled across the meadows until I found a little stream. Eagerly I wet my parched mouth, and presently I slaked my thirst, and ate a few of the date-like fruits of the flowering trees. And then I slept.
For a period of many months thereafter, I led a strange wild life—the life of a beast or a savage. It now seems to me that I must have been more than half insane, yet I had cunning of a sort. Wandering about in the woodland in the first few days, before my strength was fully recovered, I came upon a great lump of native copper. With hammer and anvil of stone I set out to shape some tools of it. First I made a knife, and then a broad blade for a wooden spear. With those weapons I soon had stalked and killed one of the great fat sloths. After several weary efforts, I achieved a fire by friction, and feasted upon roasted meat.
Many were the mad and impossible schemes that my fevered brain formed for making an attack on the flaming brain of metal, only to reject each upon consideration. As I had hurtled through the air above the pit, in my ill-starred attack in the Omnimobile, I had been much impressed by the narrowness of the bridge of cliffs between the great lake and the abyss. Now it occurred to me that I might dig a canal, and let the waters of the lake in to flood the Lord of Flame.
With that in mind, I made an expedition to the isthmus, armed with copper pick and spade. I found that my eyes had curiously deceived me, from the air. The land bridge was a wall of rock, nowhere less than a hundred feet high and four hundred thick, covered with a rank growth of jungle. Along it, even as Xenora had said, was a ruined road. Here and there a crumbling stone monument rose from the jungle like a bleached skull of the dead civilization.
There was no hope of digging a canal. A hundred men, in ten years, might have been able to cut a tunnel through that wall of stone, with modern tools and explosives! Nitroglycerine! That started me on a new line of thought. I had once made chemistry a hobby. It was not impossible. For Sam, it would have been child's play. But, alas! there was no help from my old friend!
I set to work at once. For many months I labored. The task was a tremendous one. The first necessity was an adequate supply of nitrates. I was not fortunate enough to discover a natural deposit, as heroes of fiction usually are; so I set out to make a "nitrate plantation" such as is used for the manufacture of nitrates in a primitive way. I dug a great shallow pit, lined it with waterproof clay, and filled it with alternate layers of wood ashes obtained by burning the purple trees, and everything I could pick up in the way of nitrogenous animal and vegetable refuse. At last it was filled and wet down with water from my clay-bed. I had nothing to do but wait until the nitrogen products of decomposition had united themselves with the potassium bases in the wood ashes.
Then I fell to the mining of iron pyrites, and to the building of a furnace in which I could burn my pottery apparatus. After many disheartening failures I was able to set up apparatus that I thought would suffice for the manufacture of my acids. I burned rude jars, glazed with sand, in which to carry and store my reagents and explosives.
My memory of all that time is a dim dream of terror. Many times for long hours I stood on the brink, gazing into the flickering mist, thinking of Xenora and half determined to give it all up and to seek her. But always I went back to my mad task, toiling in a daze of grief and despair.
Before I did anything more in the way of manufacture, I paid another visit to the isthmus, and selected the site for the mine which was to tear an opening in it. I found a deep crevice in the rocks, and spent many weeks in clearing and enlarging it, until I had ready a chamber deep in the heart of the barrier, below the level of the lake.