human
But how to make a start?
gpt
We will start from Deptford, said Fergusson.
human
We must first ascertain the exact time that the train left Deptford, and the precise moment when the first explosion took place. Mind you, I believe there was a series of explosions. You see, there is always a fair amount of air in the tubes. When the inflowing gas met the cross currents of air, it would be diverted, or pocketed, so to speak. We should have a big pocket of the explosive, followed by a clear space. When the switches were turned on there would be sparks here and there all along the tubes. This means that practically simultaneously the mines would be fired; fired so quickly that the series of reports would sound like one big bang. That this must be so can be seen by the state of some of the streets. In some spots the tube has been wrenched bodily from the earth as easily as if it had been a gaspipe. And then, again, you have streets that do not show the slightest damage. You must agree with me that my theory is a correct one.
gpt
I do. But what are you driving at?
human
Well, I am afraid that my theory is a very forlorn one, but I give it for what it is worth. It's just possible, faintly possible, that those trains ran into a portion of the tube where there was no explosion at all. There were explosions behind them and in front of them, and of course the machinery would have been rendered useless instantly, so that the trains may be trapped with no ingress or outlet. I'm not in the least sanguine of finding anything, but the aftermath of a fearful tragedy. Anyway, our duty is pretty plainly before us--we must go to Deptford. Come along.