On each side of me sloped upwards skylights which lighted the interiors of the building-sheds, but all were thickly coated with a composition of dockyard dust and soot, which had been poured forth from many a warship's funnel as well as from the dozens of furnaces around. All was dark below; therefore I could see nothing.
I had been in my elevated position for fully twenty minutes before I was prompted to creep along to the further end of the gulley, where, to my surprise, I saw that close to where I stood two panes of glass had been neatly removed and laid aside.
Through the hole I gazed down into the interior of the shed, when I was startled to see the small glow of an electric lamp in the hand of the man of whom we were in search.
He was standing beside the long, spindle-shaped hull of a new submarine boat which lay on a very elevated set of stocks on the far side of the shed. Another boat similar, but not so nearly complete, lay at the bottom of the dock alongside her.
As Karff with his electric lamp moved slowly and noiselessly along, carefully examining England's newest submarine, which rumour had said was the most silent and perfect craft of its kind, I was able to make out vaguely that, differing considerably from photographs of other submarines I had seen, the boat on the elevated stocks had a bow which ran out into a kind of snout, while instead of the usual small circular or oval conning-tower she had what looked like a long, narrow superstructure running along the greater part of her length. This, however, was much higher forward than aft. She seemed, too, to have a great number of propellers.
I watched the man Karff making some rapid memoranda, and so occupied was he with his work that he never looked upward. Had he done so, he would certainly have detected my head against the sky.
In a manner which showed him to be fully acquainted with the construction of submarine vessels, he moved to and fro, examining both boats. Then, after about half an hour's minute investigation, he seated himself upon a bench and with his little lamp shaded to throw no reflection he took out a piece of paper and leisurely made a rough sketch of England's newest war-craft, both side and horizontal views.
Leaving him thus occupied, I descended to Ray, and finding him secreted near the water's edge, described what I had discovered.
"Good!" he exclaimed. "So I was not mistaken in that cryptogram after all! We will allow the fellow to complete his work and then compel him to disgorge his notes. They will furnish us with very excellent evidence."
So we waited, keeping our eyes fixed upon the spot where he must descend, and hardly daring to breathe lest we should prematurely alarm him.