Scenes of commerce by land and sea Author:Isaac Taylor Purchase of this book includes free trial access to www.million-books.com where you can read more than a million books for free. This is an OCR edition with typos. Excerpt from book: 69 CLOCKS. An announcement that the clock-maker had brought home a clock, which he had taken to clean, almost unavoidably excited a desire in the young inq... more »uirers to know something about clocks. Mr. Paterson was not long in gratifying this desire. " The first method of measuring time, that we read of, was by observing the shadow projected by the sun in his daily course. Then, about one hundred and fifty years before the Christian sera, the Romans had their clepsydrae, which were tall narrow phials, filled with water, with a cork floating on the top. A small hole at the bottom of the phial allowed the water to escape gradually and regularly ; as it ran out, the cork descended, and shewed, by marks on the outside of the phial, how many hours had elapsed since the water began to flow. To this instrument, perhaps, the hour and minute glasses of later ages owe their origin ; only these have sand in them instead of water; and when all the sand has run from the upper into the lower glass, they must be turned upside down, and then the sand recommences its running. " But the measuring of time by wheel-work is a comparatively modern invention; though the inventor is not known. The first clock set up in England was in the year 1288, at Westminster. The art is now brought to great perfection in many points, which you cannot yet understand; yet the general principle is easily comprehended, as the examination of a clock in motion, out of its case, will render it quite familiar. " There, the clock is uncased; the first thing you should observe is the weight, which has a tendency to go down. In its descent it draws the line by which it is suspended; and the line, passing over a pulley, turns the wheel to which the pulley is attached. That wheel turns other wheels, which you may trac...« less