There was, however, no need to resort to this. Klees, who had been lost in thought, suddenly gripped hold of one of the valves—a hissing noise of compressed air, the depth gauge pointed wildly to 66 fathoms then sprang back to 26 again ... then the coating of slime which had stopped up the spouts of the gauge was blown away by a little of the compressed air.
The mouths of the pumps were also cleared by means of the compressed air of all the mud and slime which had worked in during our wild circular movements; then the pumps commenced humming in their usual tones, and the "Deutschland" rose obediently to the surface.
We had been, however, one hour and a half under water.
Captain Hinsch, in the "Timmins," came alongside much relieved. He had been unable to understand the meaning of our long submersion and had grown extremely anxious.
We must apparently have got into some kind of pit, where the sand was being "ground" and where, owing to our circular movements, we dug our way gradually into the slime and mud. I then posted the "Timmins" at a distance of two miles away for an observation of a last important submersion test.
Our aim was, without advancing, to rise so that the periscope appeared above water, which was by no means an easy matter. It is naturally much easier to get up to a certain position by utilising the dynamical lift given by the diving rudders, but in doing this the periscope makes a little track of foam through the sea, which might under certain conditions prove treacherous.
We tried, therefore, to lift ourselves from a greater depth by oscillating up to a certain height and, by alternately emptying and filling the tanks at that depth, to reach a floating position in which only our periscope should appear just above the water, and that in a vertical direction.
The experiment succeeded. We were able to stretch out our periscope feelers so that the "Timmins"—who knew roughly our vicinity—did not notice us before our conning-tower appeared above the water.
I now felt certain that we were prepared for all possibilities and could risk breaking through unobserved. We continued therefore calmly on our way with "Timmins" and regulated our course so that we reached the exit between the capes just after darkness had set in.