40 Fun Facts About John Napier

John Napier is said to have caught a thieving servant using which animal, secretly covered in soot?

A rooster dusted with soot did the trick: Napier told his servants it would crow when the thief stroked it, then looked for the one pair of clean hands.

John Napier reportedly caught the pigeons raiding his crops by scattering grain laced with what?

Alcohol left the birds too drunk to fly away, so Napier simply gathered them up, a feat that looked like sorcery to his neighbours.

John Napier's calculating rods are nicknamed 'bones' because many were carved from which material?

Ivory rods looked so much like bones that the name stuck, though Napier himself called his method rabdology, a word he coined for reckoning with rods.

John Napier's Bible calculations predicted that which event would come in 1688 or 1700?

The end of the world was due by 1700 on his reading of Revelation, and Napier counted his book on it, not his mathematics, as his most important work.

The neper, a unit named after John Napier, is an alternative to which unit of signal level?

The decibel is built on base-10 logarithms while the neper uses natural ones, and its odd spelling follows the Latin form of Napier's surname.

The crater Neper, named after John Napier, lies near the eastern edge of which celestial body?

The Moon carries the crater Neper so close to its eastern limb that it can be seen well only when the lunar wobble called libration tips it into view.

John Napier's logarithms led to which handheld calculating tool that engineers used until the 1970s?

The slide rule, developed by William Oughtred and others soon after Napier, put logarithmic scales on sliding sticks until pocket calculators retired it.

John Napier signed a 1594 contract with Robert Logan to search Fast Castle for what?

Hidden treasure was the prize, and Napier was promised a third of anything he found; the contract survives, but there is no sign it was ever fulfilled.

Neighbours who took John Napier for a sorcerer said he carried which creature around in a small box?

A spider, black and kept in a little box, was part of the legend, along with claims that Napier's long hours in his study were spent learning the dark arts.

John Napier's books helped popularise which everyday piece of mathematical notation?

The decimal point runs through Napier's book on constructing his tables as a plain full stop dividing whole numbers from fractions, far simpler than the circled numbers Simon Stevin had used.

John Napier's custom of strolling outdoors in which outfit helped fix his reputation as a warlock?

A nightgown and cap were his walking clothes, an old parish account records, and locals whispered that he was in compact with the devil.

Deep in calculation at Gartness, John Napier reportedly asked a neighbour to stop which noise?

A mill beside his home clacked only now and then, which broke his train of thought, while the constant roar of a nearby waterfall never troubled him.

John Napier experimented on his estates with fertilising fields using which kitchen substance?

Salt, he claimed, made land yield more grass and corn at far less cost than the dung that Scottish farmers normally spread on their fields.

Restorers in the 1960s found what lodged in the walls of Merchiston Tower, John Napier's birthplace?

A cannonball was embedded in the tower, thought to date from 1572, when supporters of the deposed Mary, Queen of Scots, fought those of her young son.

In his writings on Revelation, John Napier identified which powerful figure as the Antichrist?

The Pope was the Antichrist in Napier's fiercely Protestant reading, a view shaped by the sermons he heard as a teenage student.

John Napier's logarithms let astronomers swap long multiplication for which much simpler operation?

Addition takes over because the logarithm of a product is the sum of the logarithms, so a printed table does the hard work of multiplying.

John Napier was enrolled at which university at the remarkably young age of just 13?

St Andrews took him in 1563, with its principal asked to look after him personally, but no record shows that he ever graduated.

John Napier dedicated his 1593 book to which king of Scots, urging him to reform his court?

James VI, the future James I of England, was told bluntly to begin his reforms at home, with his own family and court.

Which English professor travelled to Edinburgh to meet John Napier and recast logarithms in base 10?

Henry Briggs stayed a whole month on his first visit and returned the following summer, then published the first table of base-10 logarithms.

At their first meeting, John Napier and an English admirer reportedly spent 15 minutes doing what?

Staring in silence, each beholding the other with admiration, is how an early account tells it, before the visitor finally spoke to praise the invention.

Which astronomer dedicated his Ephemeris to John Napier after using logarithm tables to compile it?

Johannes Kepler was so taken with logarithms that he wrote to Napier in 1619 hoping to see more of his work in print, before news reached him that the Scot was gone.

Which French mathematician said that John Napier's logarithms doubled the life of the astronomer?

Pierre-Simon Laplace, writing two centuries later, praised the invention for cutting the labour of many months to a few days and sparing astronomers their errors.

The Latin title of John Napier's 1614 book calls his canon of logarithms by which adjective?

Wonderful is the usual English for 'mirifici' in Mirifici Logarithmorum Canonis Descriptio, a slim volume with 57 pages of text and 90 pages of tables.

Roughly how long did John Napier spend calculating the tables in his 1614 book of logarithms?

About 20 years of hand calculation went into the tables, squeezed in between running his estates and writing theology, since mathematics was only his hobby.

John Napier's 'location arithmetic' moved counters on a chessboard to work in which number system?

Binary arithmetic, the language of modern computers, was Napier's trick: he wrote numbers as powers of two so that moving counters could multiply and divide.

Beyond multiplying and dividing, skilled users of John Napier's bones could also work out which results?

Square roots were within reach of the rods, and Napier's own treatise pushed the method as far as cube roots too.

John Napier, born at Merchiston Tower in 1550, was the eighth holder of which title there?

Laird of Merchiston was a landowner's title rather than a peerage; it was his heir Archibald who was raised to the nobility as the first Lord Napier.

In Italian and Finnish, which famous mathematical constant is named after John Napier?

The number e (about 2.718) is 'Napier's number' in those languages, even though the constant itself was only pinned down decades later by Jacob Bernoulli.

Which relative published John Napier's second book on logarithms, the Constructio, in 1619?

His son Robert saw the Constructio into print; Napier had written it first but held it back to see how readers received his tables.

John Napier's 1596 list of secret inventions included which weapon for use against enemy ships at a distance?

A burning mirror for torching enemy ships at any distance topped the list, drawn up when Scotland feared an invasion by Philip of Spain.

Which ailment, nicknamed the disease of kings, plagued John Napier late in life at Merchiston?

Gout pained Napier so badly that he cited it in a 1613 complaint to the Privy Council, and with overwork it is blamed for wearing him out.

John Napier designed a hydraulic screw and revolving axle to pump floodwater out of what?

Coal pits that had flooded could be cleared and worked again with his machine, and Napier was granted a monopoly on making it.

A wall memorial to John Napier stands in which Edinburgh church beside Princes Street Gardens?

St Cuthbert's was Napier's own parish church, where he served as an elder, and his remains are said to lie in a vault on its north side.

John Napier built the word logarithm from 'logos' and 'arithmos', words from which ancient language?

Greek gave him 'logos' for ratio and 'arithmos' for number, and Napier is said to have come home from his studies abroad fluent in the language.

John Napier's 1614 tables gave logarithms of which values, vital to astronomers solving triangles?

Sines for every minute of angle fill the tables, because the heaviest sums of Napier's day came from the spherical trigonometry of astronomers.

Which calculating device described by John Napier is named from the Latin word for a storehouse?

The promptuary used number strips and perforated masks to multiply long numbers, but it needed far more pieces than a set of his bones.

Which Swiss clockmaker devised logarithm-style tables on his own but published after John Napier?

Jost Bürgi worked out his tables around 1600 but printed them only after Napier's book had appeared, so the credit went to Scotland.

Which German professor built a 1623 calculating machine around rotating sets of John Napier's bones?

Wilhelm Schickard, a professor of Hebrew and astronomy, called it an arithmetical instrument; it rang a bell on overflow but was destroyed before delivery.

John Napier's memory aid for right spherical triangles is drawn as a circle or as which other shape?

A pentagon holding five parts of the triangle lets a student read off all ten of Napier's rules from just two simple patterns.

John Napier's father held which Scottish office, whose English twin later went to Isaac Newton?

Master of the Mint was the post of Sir Archibald Napier, who had been a boy of about 16 when his famous child was born.