In Pursuit of the Unknown Read Online Free PDF

was a nuisance to break a clay envelope open to find out how many tokens were inside, so the ancient accountants scratched symbols on the outside to show what was inside. Eventually they realised that once you had these symbols, you could scrap the tokens. The result was a series of written symbols for numbers – the origin of all later number symbols, and perhaps of writing too.
    Along with numbers came arithmetic: methods for adding, subtracting, multiplying, and dividing numbers. Devices like the abacus were used to do the sums; then the results could be recorded in symbols. After a time, ways were found to use the symbols to perform the calculations without mechanical assistance, although the abacus is still widely used in many parts of the world, while electronic calculators have supplanted pen and paper calculations in most other countries.
    Arithmetic proved essential in other ways, too, especially in astronomy and surveying. As the basic outlines of the physical sciences began to emerge, the fledgeling scientists needed to perform ever more elaborate calculations, by hand. Often this took up much of their time, sometimes months or years, getting in the way of more creative activities. Eventually it became essential to speed up the process. Innumerable mechanical devices were invented, but the most important breakthrough was a conceptual one: think first, calculate later. Using clever mathematics, you could make difficult calculations much easier.
    The new mathematics quickly developed a life of its own, turning out to have deep theoretical implications as well as practical ones. Today, those early ideas have become an indispensable tool throughout science,reaching even into psychology and the humanities. They were widely used until the 1980s, when computers rendered them obsolete for practical purposes, but, despite that, their importance in mathematics and science has continued to grow.
    The central idea is a mathematical technique called a logarithm. Its inventor was a Scottish laird, but it took a geometry professor with strong interests in navigation and astronomy to replace the laird’s brilliant but flawed idea by a much better one.
    In March 1615 Henry Briggs wrote a letter to James Ussher, recording a crucial event in the history of science:
    Napper, lord of Markinston, hath set my head and hands a work with his new and admirable logarithms. I hope to see him this summer, if it please God, for I never saw a book which pleased me better or made me more wonder.
    Briggs was the first professor of geometry at Gresham College in London, and ‘Napper, lord of Markinston’ was John Napier, eighth laird of Merchiston, now part of the city of Edinburgh in Scotland. Napier seems to have been a bit of a mystic; he had strong theological interests, but they mostly centred on the book of Revelation. In his view, his most important work was A Plaine Discovery of the Whole Revelation of St John , which led him to predict that the world would end in either 1688 or 1700. He is thought to have engaged in both alchemy and necromancy, and his interests in the occult lent him a reputation as a magician. According to rumour, he carried a black spider in a small box everywhere he went, and possessed a ‘familiar’, or magical companion: a black cockerel. According to one of his descendants, Mark Napier, John employed his familiar to catch servants who were stealing. He locked the suspect in a room with the cockerel and instructed them to stroke it, telling them that his magical bird would unerringly detect the guilty. But Napier’s mysticism had a rational core, which in this particular instance involved coating the cockerel with a thin layer of soot. An innocent servant would be confident enough to stroke the bird as instructed, and would get soot on their hands. A guilty one, fearing detection, would avoid stroking the bird. So, ironically, clean hands proved you were guilty.
    Napier devoted much of his