An undersized, lean, wizen-faced man, with an immense bald head, as round and smooth and shining as a giant soap-bubble, and a pair of beady black eyes, set close together, so that he resembled a gnome of amazing brain capacity and prodigious power of concentration, sat bent over a writing desk with a huge sheet of cardboard before him, on which he was swiftly drawing geometrical and trigonometrical figures. Compasses, T-squares, rulers, protractors, and ellipsographs obeyed the touch of his fingers as if inspired with life.