“Our troubles!” said the doctor. “Many of our troubles, to be sure, arise from our passions and appetites--in other words, from our selfishness--and these will no doubt disappear when we reach that blessed state of which you have spoken, a condition prayed for and dimly expected by many of our race. But other troubles of ours come from sickness and severe toil, from accidents, famines, and the convulsions of nature. How, for example, can you have escaped the latter, unless, indeed, God has helped those who have so wisely helped themselves?” “Your last thought is right,” answered our friend. “Nature has certainly assisted us. While the crust of the planet was thin we know the central fires heaved and shook the ground and burst forth from the mountains, causing great destruction and keeping the world in fear. We do not know how thick the crust of the planet now is, but nothing has been felt of those inner convulsions for many ages. One of our feats of engineering has been to see how far we could penetrate into the surface of the globe. A well of vast size has been dug, the temperature being carefully noted and observations made of the many different substances passed through--water, coal, gas, oil, and all kinds of mineral deposits. The work has progressed from one generation to another, and no one can tell when it will be called finished, as it is determined to dig toward the center of the planet as fast as our ever-increasing skill will permit.” “Did you find out how thick the crust is?” I asked. “No,” he answered, “we are not much nearer the solution of that question than before, but we have made valuable discoveries as to what the crust is composed of. The temperature has gradually, though slowly, increased, and we believe the time will come when the work will have to be abandoned on account of the heat. We have gone far enough to know that when the fuel on the surface of our globe is all used up we shall only have to tap the center to get all the heat we want.” “What a capital idea that will be,” I interrupted, “to throw at some of our pessimistic friends on the earth, Doctor.” “We see now, Thorwald,” my companion said, “that your planet is too old to give you any more trouble from earthquake and volcano, but how about other natural phenomena, the tempest and cyclone for example?” “Well,” replied Thorwald, “we have a theory that time, the great healer, has cured these evils also. Let me ask, Doctor, if the earth ever receives any accretions of matter from outside its own atmosphere?” “Yes, we have the fall of meteorites, foreign substances which we believe the earth encounters in its path around the sun.”