Overview

In Xanadu did Kublai Khan a stately pleasure-dome decree, where Alph, the sacred river, ran through caverns measureless to man down to a sunless sea, so twice five miles of fertile ground with walls and towers were girdled round Samuel Coleridge Taylor 1798

To the inexperienced, though inventive designer, the idea of units of measure may seem unnecessarily pedantic in the context of make-and-test projects. The substantive argument for considering units, and (shock, horror!) conversions between units, is that they form part of the formal engineering language that permits communication between problem specifier and problem solver. In addition, the history of units and their adoption by various institutions and countries provides a fascinating and often illuminating insight into human nature "in the large".

Although difficult to prove, it is likely that even early cavemen used units of measure for exchange ( e.g., "my cave is the height of two Triceratops" about 4 metres, or "I wish to trade five spears of the length of a tyrannosaurus skull" approximately 1.5 metre). It is certainly true that the compilers of the Old Testament used units of measure as in the case of God instructing Noah (Genesis 6)

14 Make thee an ark of gopher wood; rooms shalt thou make in the ark, and shalt pitch it within and without with pitch.

15 And this is the fashion which thou shalt make it of: The length of the ark shall be three hundred cubits, the breadth of it fifty cubits,...