John Napier

John Napier of Merchistoun (1550 – 4 April 1617), the son of Sir Archibald Napier of Merchiston and Janet Bothwell, was a mathematician, physicist, astrologer and 8th Laird of Merchistoun. His surname appears in many different spellings - Napeir, Nepair, Nepeir, Neper, Napare, Naper, Naipper - but John Napier would most commonly have been written Jhone Neper in his time. Napier is most remembered as the inventor of logarithms and "Napier's bones", (a multiplication tool using a set of numbered ivory rods), and for popularizing the use of the decimal point. He also contributed a mnemonic for formulas used in solving spherical triangles, and two formulas known as Napier's analogies. Napier's birth place, Merchiston Tower, Edinburgh, Scotland, is now part of Napier University. Neper crater, on the Moon, is named after him,[1] as is an asteroid, 7096 Napier. After dying of gout, Napier was buried in St Cuthbert's Church, Edinburgh.

Little is known about John Napier's early years, but a letter survives written by the Bishop of Orkney, who was John's uncle, to Archibald Napier when John was eleven years old:-

I pray you, schir, to send your son Jhone to the schuyllis; oyer to France or Flandaris; for he can leyr na guid at hame, nor get na proffeitt in this maist perullous worlde ...

Napier entered St Andrew's University a the age of 13, where he became passionately interested in theology. There is no record of his having graduated, and it appears that he probably learned his mathematics elsewhere, possibly during his travels in Europe. In 1571, Napier returned to Scotland, and the following year married Elizabeth Stirling, daughter of Scottish mathematician James Stirling (1692-1770), and bought a castle at Gartnes. The couple had two children before Elizabeth died in 1579. Napier later married Agnes Chisholm, with whom he had ten children. When his father died in 1608, Napier and his family moved into Merchiston Castle, where he lived the rest of his life. There,he became known as "Marvellous Merchiston" for the mechanisms he built to improve his crops and cattle.

Logarithms

Napier's invention of logarithms was an extremely important advance, and the ease of calculation that this introduced allowed Kepler to make the breakthrough that underpinned Newton's theory of gravitation. In the preface to the Mirifici logarithmorum canonis descriptio, Napier says

Seeing there is nothing (right well-beloved Students of the Mathematics) that is so troublesome to mathematical practice, nor that doth more molest and hinder calculators, than the multiplications, divisions, square and cubical extractions of great numbers, which besides the tedious expense of time are for the most part subject to many slippery errors, I began therefore to consider in my mind by what certain and ready art I might remove those hindrances. And having thought upon many things to this purpose, I found at length some excellent brief rules to be treated of (perhaps) hereafter. But amongst all, none more profitable than this which together with the hard and tedious multiplications, divisions, and extractions of roots, doth also cast away from the work itself even the very numbers themselves that are to be multiplied, divided and resolved into roots, and putteth other numbers in their place which perform as much as they can do, only by addition and subtraction, division by two or division by three.

The book contained just thirty-seven pages of explanation but importantly, ninety pages of tables. Laplace, 200 year later, was to say that logarithms: "...by shortening the labours, doubled the life of the astronomer."

Theology

Napier was a fervent Protestant (and rabidly anti-Catholic), and in A Plaine Discovery of the Whole Revelation of St. John, which he regarded as his most important work, Napier used the Book of Revelation to predict the Apocalypse, which he predicted would occur in 1688 or 1700.

Rumours circulated that Napier was "in league with the powers of darkness", and these are taken seriously in a biography [7] written by Mark Napier, one of John Napier's descendants, who claims that John Napier deliberately played to the superstitions of his servants by going round with a cock which he had covered with soot, pretending it to be his familiar spirit.

Napier was able to use his black rooster to tell which of his servants had been stealing from his home. He would shut the suspects in a room with the rooster one at a time and told them to stroke it and it would then tell Napier who had done it. In actual fact what would happen is that he would cover the rooster in soot and the servants who were innocent would have no problem stroking it but the guilty would pretend he had and when Napier examined their hands, the one with the clean hands was guilty.