them at an expense of nearly £20, they performed their work satisfactorily. The information they gave might be fully relied upon.
We had an excellent illustration of this on one occasion when we were returning, late in the evening, from Maidenhead, after a hard day's work. The pitchy darkness of the night, which prevented us from seeing any objects external to our carriage, was strongly contrasted with the bright light of four argand lamps within it. I was accompanied by my eldest son, Mr. Herschel Babbage, and three assistants. A roll of paper a thousand feet in length was slowly unwinding itself upon the long table extended before us, and winding itself up on a corresponding roller at its other extremity. About a dozen pens connected with a bridge crossing the middle of the table were each marking its own independent curve gradually or by jumps, as the circumstances attending our railway course was dictating. The self-feeding pens, which the self-acting roller of blotting-paper continually followed, but never overtook, were quietly marking their inevitable courses. All had gone on well for a considerable time amidst perfect silence, if the steady pace of thirty miles an hour, the dogged automatic action of the material, and the muteness of the living machinery, admitted of such a term. Being myself entirely ignorant of our position upon the rail, I disturbed this busy repose by inquiring whether any one knew where we were? To this question there was no reply. Each continued to watch in silence for the duties which his own department might at any moment require, but no such demands were made.
After some minutes, as I was watching the lengthening curves, I perceived a slight indication of our position on the railroad. I instantly looked at my son, and saw, by a faint
