We'd accomplished—what? Only something remotely confirming Matzuku, the Japanese who had located us in the Kalahari Desert of Africa.
We slept by fits and starts. The Shadow Men did not return. Silence held sway in our walkie-talkie receivers, though we kept on sending. Ziegler gave us Mangbetu words to use, but nothing came of it. That line of investigation was clearly ended.
We began working on the inner wall of the dome with our entrenching tools. That started something!
It was now clear that if we ever got out of wherever we were, we would have to do it on our own.
First, to establish the exact circumference of the dome, I formed all hands, sailors, marines and Japanese, in a single column and we did the circle. I wanted everybody whose lot was our lot, to know every detail that might later prove valuable. The area under our feet, available to us within the dome, we estimated at ten acres. That gave us considerable inner surface of wall and dome to be studied. We could not see the dome, we only knew it was there. We had small radar and sonar sets, but the dome registered on neither. Nothing we shouted was echoed back to us, nor did the chattering of the fast-firers cause reverberations. With those fast-firers, the ultimate in small arms, we searched out every quadrant of the dome, to see if there were any opening. In the same way we searched out every yard of the wall; there was no way out, at least of any size, for I'd have wagered, so carefully was this job done, that if one bullet fired into dome or wall had fallen outside, some one of us would have spotted it.
We used up a lot of steel-jacketed bullets, but we found not a single aperture in the wall or dome.
Next we worked on our super-grenades, of which we had a fairly good supply. This was dangerous work; we had to dig trenches from which to heave them. Even the rifle grenades were dangerous because of our limited escape area.
The grenades did nothing to the wall; nothing whatever.
The flame-throwers accomplished little more. There was danger with these, too, for the flame bathed the wall—we could see it strike and blossom up and down—and backfired so that it was a wonder all who stood behind the machines were not wiped out. And even the flames did not affect the wall.