Mr. Polton Explains

"But I shall not here anticipate the later passages of my story. The consequences will emerge in their proper place. I may, however, refer briefly to the more immediate reactions, though these also had their importance later. The little book which I had purchased (and paid for the same evening) was a treatise on clocks and locks by that incomparable master of horology and mechanism, Edmund Beckett Denison (later to be known as Lord Grimthorpe). It was an invaluable book, and it became my chiefest treasure. Carefully wrapped in a protective cover of brown paper, the precious volume was henceforth my constant companion. The abstruse mathematical sections I had regretfully to pass over, but the descriptive parts were read and re-read until I could have recited them from memory. Even the drawings of the Great Westminster Clock, which had at first appeared so bewildering, became intelligible by repeated study, and the intricacies of gravity escapements and maintaining powers grew simple by familiarity."