John Bevis

Lore & Background

Bevis was educated at Christ Church, Oxford, earning his B.A. in 1715 and M.A. in 1718. In 1757 he published 'The History and Philosophy of Earthquakes', collecting accounts of the 1755 Lisbon earthquake from diverse authentic sources, a survey later used by John Michell. That same year, tobacconist Thomas Hughes asked Bevis to investigate why no flowers would grow in his garden at Bagnigge House near King's Cross Road, London. Bevis found the well water full of iron; a second well yielded purgative water, leading to the establishment of Bagnigge Wells spa in 1758. He was elected a Fellow of the Royal Society in November 1765.

In electrical research, when the Leyden jar first arrived in the UK in 1746, Bevis worked with William Watson to refine it. They replaced water with lead shot, then lined the glass with lead. They experimented to determine the speed of electricity using nearly four kilometers of wire, observing no time delay and concluding it was almost instantaneous. Watson and Bevis corresponded extensively with Benjamin Franklin and his group, jointly refining the Leyden jar with tin foil, creating a battery by joining jars, distinguishing series from parallel connections, developing a flat glass-plate condenser, and introducing the single-fluid theory of electricity with positive and negative charges.

As an astronomer, besides discovering the Crab Nebula (later catalogued as M1), Bevis observed an occultation of Mercury by Venus on 28 May 1737 NS and found a prediction rule for eclipses of Jupiter's moons. He proposed a modern British star atlas, Uranographia Britannica, first advertised in April 1748. Based on Flamsteed's star positions and Bevis's own observations from 1738–1739, it was the first classical star atlas to include non-stellar objects. The project was terminated in 1750 when his publisher John Neale was declared bankrupt and the copper plates sequestered. After Bevis's death, three near-complete atlases were sold, and remaining charts were compiled into Atlas Celeste (1786). Three Uranographia copies are known: at the American Philosophical Society, St John's College Cambridge, and Chatsworth House.

Reader's Guide

John Bevis's significance lies in his diverse contributions across medicine, electrical science, and astronomy. His discovery of the Crab Nebula in 1731 remains a landmark in observational astronomy, later becoming the first object in Messier's catalogue. His electrical work with William Watson advanced understanding of the Leyden jar, leading to practical refinements and the theoretical framework of positive and negative charges, which influenced Benjamin Franklin's experiments. Bevis's compilation of earthquake accounts provided an early systematic survey of seismic events, used by later researchers. His proposed Uranographia Britannica, though never published as intended, represents an ambitious effort to create a comprehensive British star atlas incorporating non-stellar objects. The eventual posthumous release of Atlas Celeste preserved much of his astronomical work. His investigation of Bagnigge House's water led to a popular spa, illustrating the practical application of his scientific skills. Bevis's legacy is that of a versatile Enlightenment figure whose work spanned natural philosophy, medicine, and public health.

Did You Know?

• Bevis died in 1771 from natural causes, not from falling off his telescope.
• He was an acquaintance of Thomas Paine when living at the Temple.
• His 1757 work 'The History and Philosophy of Earthquakes' collected accounts of the Lisbon earthquake, though earlier compilations existed.
• Bevis and William Watson used nearly four kilometers of wire to test the speed of electricity.

The 1731 Identification

In 1731, the English astronomer John Bevis made a discovery that would permanently link his name to one of the most studied objects in the night sky. He was the first person to identify what is now known as the Crab Nebula, a luminous remnant situated in the constellation of Taurus. At the time of his observation, the object carried no common name and no catalogue designation; those would arrive later, as Charles Messier would number it M1 and the broader astronomical community would assign it NGC 1952 and the label Taurus A. Bevis's identification preceded every subsequent European observer of the nebula. His recognition of this faint object—too dim for the unaided eye at an apparent magnitude of 8.4, comparable to Saturn's moon Titan, but discernible through binoculars under favourable conditions—marked the opening entry in a long chain of observations. Though the nebula would be independently rediscovered by Messier in 1758 while searching for Halley's Comet, and later examined in detail by William Herschel and the Earl of Rosse, it was Bevis who first recorded its existence for the astronomical record.

A Pioneer in the Observational Lineage

John Bevis occupies the earliest rung in a well-documented sequence of observers who turned their instruments toward the Crab Nebula. His 1731 identification stands at the head of a lineage that includes Charles Messier's independent rediscovery in 1758, William Herschel's repeated observations spanning 1783 to 1809, and William Parsons, 3rd Earl of Rosse, who in the early 1840s produced the drawing that gave the nebula its enduring common name. Each of these later observers built upon or independently encountered the same object that Bevis had first catalogued. Messier stumbled upon it while hunting for a comet, concluding after careful observation that the faint glow did not shift position across the sky and therefore could not be a wandering body. Herschel, working over nearly three decades, ultimately concluded the nebula was composed of a group of stars. Rosse's 36-inch telescope at Birr Castle revealed the distinctive arm-like structures that inspired the crab analogy. Bevis, working more than a century before any of them, established the foundational record that made all subsequent study possible.

Uncovering a Supernova Remnant

What John Bevis identified in 1731 was, in modern understanding, far more remarkable than a simple patch of nebulous light. The Crab Nebula is a supernova remnant and a pulsar wind nebula, the expanding debris of a massive, exploding star that had exhausted its nuclear fuel centuries before Bevis first noted the object. Chinese astronomers recorded a brilliant guest star in the same region of sky on 4 July 1054, and Japanese observers made a similar entry weeks earlier. The nebula lies in the Perseus Arm of the Milky Way, approximately 2.0 kiloparsecs—about 6,500 light-years—from Earth, and spans roughly 3.4 parsecs, or 11 light-years, in diameter. It continues expanding at approximately 1,500 kilometres per second, roughly half a percent of the speed of light. At its core sits the Crab Pulsar, a neutron star only 28 to 30 kilometres across that spins 30.2 times every second, emitting a continuous sweep of radiation from gamma rays down to radio waves. Bevis, of course, had no way of knowing any of this; he simply noted a faint object in Taurus. Yet his observation is the starting point of every subsequent investigation into this extraordinary stellar corpse.

The First Supernova Link and a Lasting Scientific Tool

Perhaps the most consequential dimension of what John Bevis identified in 1731 is the role it would later play in confirming supernovae as a recognized class of stellar event. The Crab Nebula became the first astronomical object recognized as the direct product of a historically witnessed supernova explosion. In the early twentieth century, analysis of photographs taken years apart revealed the nebula was expanding; tracing that expansion backward pointed to an origin roughly nine centuries earlier, matching the guest star recorded by Chinese astronomers in 1054. Edwin Hubble proposed the formal association in 1928, and Nicholas Mayall later confirmed that the 1054 event was undoubtedly the supernova whose blast created the nebula. This single connection opened the door to the broader search for historical supernovae, ultimately yielding seven additional confirmed sightings. The nebula Bevis first noted also serves as a powerful tool in modern astrophysics: its radio waves allowed mapping of the Sun's corona in the 1950s and 1960s, and in 2003, X-rays from the nebula were used to measure the atmospheric thickness of Saturn's moon Titan. At X-ray and gamma-ray energies above 30 keV, it remains the brightest persistent gamma-ray source in the sky. Bevis's single 1731 observation thus underpins a vast and still-growing body of scientific knowledge.