"The clock, not the steam engine, is the key machine of the modern industrial age." (Mumford, "The Monestary and the Clock", page 326.) represents the thesis of Mumford's "The Monastery and the Clock". Couple of centuries ago it would be hard to find this thesis believable, but in today's world almost everything is driven by the time and ability to measure the time. Without the invention of the clock would be hard, if not impossible, to imagine the world we have today. The earliest clocks were very simple, and as the time passed, men found ways to improve the means of measuring time. First clocks used shadow produced by vertical stick to measure time, but this was not very accur