John Arnold
Encyclopedia
- This article is about the watchmaker and inventor, and his son. For others of the same name, see John Arnold (disambiguation)John Arnold (disambiguation)John Arnold was an English watchmaker and inventor, with a son named John Roger Arnold .John Arnold may also refer to:*John Arnold , English international footballer and test cricketer...
.
John Arnold (born 1736 probably in Bodmin
Bodmin
Bodmin is a civil parish and major town in Cornwall, England, United Kingdom. It is situated in the centre of the county southwest of Bodmin Moor.The extent of the civil parish corresponds fairly closely to that of the town so is mostly urban in character...
, Cornwall
Cornwall
Cornwall is a unitary authority and ceremonial county of England, within the United Kingdom. It is bordered to the north and west by the Celtic Sea, to the south by the English Channel, and to the east by the county of Devon, over the River Tamar. Cornwall has a population of , and covers an area of...
– died 1799 in London
London
London is the capital city of :England and the :United Kingdom, the largest metropolitan area in the United Kingdom, and the largest urban zone in the European Union by most measures. Located on the River Thames, London has been a major settlement for two millennia, its history going back to its...
) was an English
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
watchmaker
Watchmaker
A watchmaker is an artisan who makes and repairs watches. Since virtually all watches are now factory made, most modern watchmakers solely repair watches. However, originally they were master craftsmen who built watches, including all their parts, by hand...
and inventor.
John Arnold was the first to design a watch that was both practical and accurate, and also brought the term "Chronometer
Chronometer
Chronometer may refer to:* Chronometer watch, a watch tested and certified to meet certain precision standards* Hydrochronometer, a water clock* Marine chronometer, a timekeeper used for celestial navigation...
" in to use in its modern sense, meaning a precision timekeeper. His technical advances enabled the quantity production of Marine Chronometers for use on board ships from around 1782. The basic design of these, with a few modifications unchanged until the late twentieth century. With regard to his legacy one can say that both he and Abraham-Louis Breguet largely invented the modern mechanical watch. Certainly one of his most important inventions, the Overcoil balance spring
Balance spring
A balance spring, or hairspring, is a part used in mechanical timepieces. The balance spring, attached to the balance wheel, controls the speed at which the wheels of the timepiece turn, and thus the rate of movement of the hands...
is still to be found in most mechanical wrist watches to this day.
It can be said that, from around 1770, Arnold continued the development of portable precision timekeepers almost from the point at which the development of John Harrison
John Harrison
John Harrison was a self-educated English clockmaker. He invented the marine chronometer, a long-sought device in solving the problem of establishing the East-West position or longitude of a ship at sea, thus revolutionising and extending the possibility of safe long distance sea travel in the Age...
's precision timekeeper had ended.
Compared to Harrison's watch, the basic design of Arnold's was very simple whilst being both consistently accurate and mechanically reliable. Importantly, the relatively conventional design of the movement
Movement (clockwork)
In horology, a movement is the internal mechanism of a clock or watch, as opposed to the case, which encloses and protects the movement, and the face which displays the time. The term originated with mechanical timepieces, whose movements are made of many moving parts...
facilitated its production in quantity at a reasonable price, also at the same time enabling easier maintenance.
Three elements were essential to this achievement:
- a detached escapementEscapementIn mechanical watches and clocks, an escapement is a device that transfers energy to the timekeeping element and enables counting the number of oscillations of the timekeeping element...
, which gave minimal interference with the vibrating balanceBalance- Equipment :* Balance beam, a piece of gymnastics apparatus.* Balance board, a piece of training equipment.* Balancing machine, a machine that balances mechanical rotating parts to lessen vibration.* Balance wheel, a watch component....
and balance springBalance springA balance spring, or hairspring, is a part used in mechanical timepieces. The balance spring, attached to the balance wheel, controls the speed at which the wheels of the timepiece turn, and thus the rate of movement of the hands...
, - a balanceBalance- Equipment :* Balance beam, a piece of gymnastics apparatus.* Balance board, a piece of training equipment.* Balancing machine, a machine that balances mechanical rotating parts to lessen vibration.* Balance wheel, a watch component....
design that enabled compensation for the effect of temperature on the balance springBalance springA balance spring, or hairspring, is a part used in mechanical timepieces. The balance spring, attached to the balance wheel, controls the speed at which the wheels of the timepiece turn, and thus the rate of movement of the hands...
, - a method for adjusting the balance spring, so that the balance oscillates in equal time periods even through different degrees of balance arc (isochronism).
Early life and work
John Arnold was apprenticed to his father, also a clockmaker, in BodminBodmin
Bodmin is a civil parish and major town in Cornwall, England, United Kingdom. It is situated in the centre of the county southwest of Bodmin Moor.The extent of the civil parish corresponds fairly closely to that of the town so is mostly urban in character...
. He probably also worked with his uncle, a gunsmith. Around 1755, when he was 19, he left England and worked as a watchmaker in the Hague
The Hague
The Hague is the capital city of the province of South Holland in the Netherlands. With a population of 500,000 inhabitants , it is the third largest city of the Netherlands, after Amsterdam and Rotterdam...
, Holland, returning to England around 1757.
In 1762, whilst at St Albans
St Albans
St Albans is a city in southern Hertfordshire, England, around north of central London, which forms the main urban area of the City and District of St Albans. It is a historic market town, and is now a sought-after dormitory town within the London commuter belt...
, Hertfordshire
Hertfordshire
Hertfordshire is a ceremonial and non-metropolitan county in the East region of England. The county town is Hertford.The county is one of the Home Counties and lies inland, bordered by Greater London , Buckinghamshire , Bedfordshire , Cambridgeshire and...
, he encountered William McGuire for whom he repaired a repeating watch. Arnold made a sufficient impression so that McGuire gave him a loan, enabling him to set up in business as a watchmaker at Devereux Court, Strand, London
Strand, London
Strand is a street in the City of Westminster, London, England. The street is just over three-quarters of a mile long. It currently starts at Trafalgar Square and runs east to join Fleet Street at Temple Bar, which marks the boundary of the City of London at this point, though its historical length...
. In 1764, Arnold obtained permission to present to King George III
George III of the United Kingdom
George III was King of Great Britain and King of Ireland from 25 October 1760 until the union of these two countries on 1 January 1801, after which he was King of the United Kingdom of Great Britain and Ireland until his death...
an exceptionally small half quarter repeating watch cylinder escapement watch mounted in a ring. A similar repeating watch by Arnold has survived; it is of interest that the basic movement is Swiss in origin but finished in London. The escapement of this watch was later fitted with one of the first jewelled cylinders made of ruby.
Arnold made another watch for the King around 1768, which was a gold and enamel pair cased watch with a movement that had every refinement, including minute repetition and centre seconds motion. In addition, Arnold fitted bi-metallic temperature compensation, and not only was every pivot hole jewelled but the escapement also had a stone cylinder made of ruby or sapphire. This watch Arnold designated "Number 1" as he did with all watches he made that he regarded as significant, these numbering twenty in all.
Other early productions by Arnold from 1768 to 1770 display both originality and ingenuity; this includes a centre seconds watch wound up by depressing the pendant once a day. The movement of this watch also was fully jewelled with a temperature compensation device and a ruby stone cylinder escapement.
These watches were made as demonstrations of Arnold's talent, and, in terms of style and substance, were similar to other "conversation pieces" being made at the same time as those being produced for James Cox
James Cox (inventor)
James Cox was a British jeweller, goldsmith and entrepreneur best known for creating mechanical clocks, including Cox's timepiece and the Peacock Clock from the State Hermitage Museum in Saint Petersburg....
and made primarily for export to the East.
The technical challenge
Arnold's facility and ingenuity, coupled with his undoubted charm brought him to the attention of the Astronomer RoyalAstronomer Royal
Astronomer Royal is a senior post in the Royal Household of the Sovereign of the United Kingdom. There are two officers, the senior being the Astronomer Royal dating from 22 June 1675; the second is the Astronomer Royal for Scotland dating from 1834....
Neville Maskelyne, who at this time was seeking a watchmaker skilled enough to make a copy of John Harrison
John Harrison
John Harrison was a self-educated English clockmaker. He invented the marine chronometer, a long-sought device in solving the problem of establishing the East-West position or longitude of a ship at sea, thus revolutionising and extending the possibility of safe long distance sea travel in the Age...
's successful marine timekeeper. A full and detailed description of this watch was published by the Board of Longitude
Board of Longitude
The Board of Longitude was the popular name for the Commissioners for the Discovery of the Longitude at Sea. It was a British Government body formed in 1714 to administer a scheme of prizes intended to encourage innovators to solve the problem of finding longitude at sea.-Origins:Navigators and...
in 1767, entitled "The Principles of Mr. Harrison's Timekeeper", the intention clearly being for it to act as a blueprint for future quantity production. In fact it was a highly complex and technically very advanced piece of micro engineering, and capable of being reproduced by less than a handful of watchmakers. However, the challenge was taken up by Larcum Kendall
Larcum Kendall
Larcum Kendall was a British watchmaker.-Commission:The Board of Longitude asked Kendall to copy and develop John Harrison's ingenious fourth model of a clock useful for navigation at sea...
,who spent two years to make a copy (now known as "K1") that cost £450, a huge sum at the time. Although successful as a precision timekeeper, the Admiralty wanted a timekeeper on every major ship, and Kendall's was too expensive and took too long to make. Kendall made a simplified version (K2) in 1771, but this too was costly, and not as accurate as the original.
In retrospect therefore, it was a significant occasion when in 1767 Neville Maskelyne presented John Arnold with a newly printed copy of the "Principles of Mr. Harrison's Timekeeper", evidently with a view to encourage him to make a precision timekeeper of the same kind.
Following this, Maskelyne encouraged Arnold by employing him on several occasions, mostly in connection with watch and clock jewelling. In 1769 Arnold modified Maskelyne's centre seconds watch by John Ellicott
John Ellicott (1706 – 1772)
John Ellicott , was an eminent English clock and watchmaker of the 18th century.His father, a Cornishman, John Ellicott , was also a clockmaker and had been admitted to the Clockmakers' Company in 1696...
, changing the cylinder escapement from steel to one made of sapphire
Sapphire
Sapphire is a gemstone variety of the mineral corundum, an aluminium oxide , when it is a color other than red or dark pink; in which case the gem would instead be called a ruby, considered to be a different gemstone. Trace amounts of other elements such as iron, titanium, or chromium can give...
. This watch he lent to the Astronomer William Wales
William Wales (astronomer)
William Wales was a British mathematician and astronomer.-Early life:Wales was born around 1734 to John and Sarah Wales and was baptized in Warmfield that year...
for use in assessing the practicability of Maskelyne's Lunar distance method for finding the ship's Longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
during the voyage of the Transit of Venus
Transit of Venus
A transit of Venus across the Sun takes place when the planet Venus passes directly between the Sun and Earth, becoming visible against the solar disk. During a transit, Venus can be seen from Earth as a small black disk moving across the face of the Sun...
expedition to the West Indies in 1769. Around this time Arnold also seems to have started to think about making an accurate timekeeper to find the Longitude
Longitude
Longitude is a geographic coordinate that specifies the east-west position of a point on the Earth's surface. It is an angular measurement, usually expressed in degrees, minutes and seconds, and denoted by the Greek letter lambda ....
.
Arnold's first "Watch Machines"
Arnold's approach to precision timekeeping was completely different to that of Harrison whose technical ethos was rooted in seventeenth and early eighteenth century theory and practise.Arnold knew that as the balance and balance spring control the timekeeping in a portable watch, he only needed to find a way of giving the balance a consistent impulse with minimal interference from the wheel work, together with an effective temperature compensation. After making some experimental machines, he produced what could be regarded as a production model to the Board of Longitude in March 1771.
This machine was completely different to Harrison's watch. It was a mahogany
Mahogany
The name mahogany is used when referring to numerous varieties of dark-colored hardwood. It is a native American word originally used for the wood of the species Swietenia mahagoni, known as West Indian or Cuban mahogany....
box of approximately 6 x 6 x 3 inches that housed a movement that, though relatively simple, was close to the same size as Harrison's, with a balance of a similar diameter. The radical difference, however, was a newly designed escapement that featured a horizontally placed pivoted detent that allowed the balance to vibrate freely, except when impulsed by the escape wheel. The spiral balance spring also had a temperature compensation device similar to those in Arnold's watches, and based on Harrison's bimetallic strip of brass and steel. Arnold proposed manufacture of these timekeepers at 60 guineas each.
Three of these timekeepers traveled with the explorers James Cook
James Cook
Captain James Cook, FRS, RN was a British explorer, navigator and cartographer who ultimately rose to the rank of captain in the Royal Navy...
and Captain Furneaux during their second voyage to the southern Pacific Ocean
Pacific Ocean
The Pacific Ocean is the largest of the Earth's oceanic divisions. It extends from the Arctic in the north to the Southern Ocean in the south, bounded by Asia and Australia in the west, and the Americas in the east.At 165.2 million square kilometres in area, this largest division of the World...
in 1772-1775. Captain Cook also had Kendall's first timekeeper on board as well as one of Arnold's. Whereas Kendall's performed very well and kept excellent time during the voyage, only one of Arnold's was still running on their return to England in 1775.
During this period, Arnold also made at least one precision pocket watch, a miniature version of the larger marine timekeepers.
This surviving watch watch dates from around 1769-1770, and is signed Arnold No. 1 Invenit et Fecit. The movement, which indicates centre seconds, has a steel balance with a bimetallic temperature compensation strip that acts on the flat balance spring. Though now altered, the original escapement was Arnold's horizontal pivoted detent as fitted to the larger timekeepers, which was it seems not entirely successful and needed improvements.
Around 1772, Arnold modified this escapement so that it now was pivoted vertically and acted on by a spring. This was a much more successful arrangement, and it is known that in 1772 at least two pocket timekeepers with this escapement were supplied to Joseph Banks
Joseph Banks
Sir Joseph Banks, 1st Baronet, GCB, PRS was an English naturalist, botanist and patron of the natural sciences. He took part in Captain James Cook's first great voyage . Banks is credited with the introduction to the Western world of eucalyptus, acacia, mimosa and the genus named after him,...
at a cost of £100 and also Banks' fellow Etonian
Eton College
Eton College, often referred to simply as Eton, is a British independent school for boys aged 13 to 18. It was founded in 1440 by King Henry VI as "The King's College of Our Lady of Eton besides Wyndsor"....
Captain Constantine John Phipps, 2nd Baron Mulgrave.
In 1773, Captain Phipps made a voyage to the North Pole
North Pole
The North Pole, also known as the Geographic North Pole or Terrestrial North Pole, is, subject to the caveats explained below, defined as the point in the northern hemisphere where the Earth's axis of rotation meets its surface...
taking with him not only his Arnold pocket timekeeper and an Arnold box timekeeper in gimbals, but also Kendall's "K2" timekeeper. From Phipps's account, it appears that the pocket watch performed very well indeed, and was a convenient instrument for ascertaining the longitude.
By 1772, Arnold had finalized the design of his pocket timekeepers and started series production with a standardized movement caliper, this being around 50 mm in diameter, larger than a conventional watch of the period, and showing seconds with a pivoted detent escapement and spiral compensation curb. However, the latter appears to have proved ineffective, which seems to have substantially slowed the rate of production.
Even though he produced a number of pocket timekeepers, from around 1772-1778, Arnold was still experimenting with different types of compensation balance and methods of balance spring adjustment. The most difficult problem to surmount was the problem of making an effective and continuously adjustable temperature compensation device. For technical reasons, the temperature compensation for the balance spring had somehow to be incorporated into the balance itself and not act on the balance spring directly as had been done previously by Arnold and others.
Arnold's first patent of 1775
In 1775, Arnold took out a patent for a new form of Compensation balance with a bimetallicBimetallic
Bimetallic may refer to:*Bimetallism, a monetary standard in economics*Bimetallic strip, a temperature sensitive mechanical device*Binary alloy, in metallurgy, a mixture of two metals*Bimetallic coins...
spiral at the centre. This spiral actuated two weighted arms making them move in and out from the centre, changing the radius of gyration and thus the period of oscillation.
In the same patent, he included a new helical balance spring. This shape reduced lateral thrust on the balance pivots as they rotated, and reduced random errors from the "point of attachment" effect, which any balance with a flat spring suffers from. As Arnold stated rather succinctly in a 1782 letter to the Board of Longitude, "...the power in all parts of the spring is uniform."
The fact that Arnold had recognized the technical advantages of a balance spring of this form clearly demonstrates a high degree of insight. The balance that was the subject of the patent appears to have been an unsuccessful design. Certainly some marine chronometers used this balance, but none have survived. Pearson records a balance of this kind in his possession that was 2.4 inches in diameter.
From 1772 to 1775, Arnold also made about thirty five pocket timekeepers. Not many, about ten of these, survive and none in their original form, as Arnold was constantly upgrading their specification. They appear originally to have had a pivoted detent escapement, with a steel balance and a helical balance spring. A spiral bimetallic curb acting on this spring was intended to provide the temperature compensation, but this system evidently did not work, as every watch was subsequently altered and improved by Arnold shortly afterwards. Surviving chronometers from this series include Numbers 3,29 and 28.
Further experimentation and invention by Arnold led to a breakthrough in the late 1770s. He redesigned the compensation balance and developed two designs that showed promise. Known as the "T" and "S" balances, and marked as such in Arnold's 1782 patent (probably because of their appearance), both employed bimetallic strips of brass and steel with weights attached, which changed the radius of gyration with change in temperature. Although these probably needed a lot of adjustment, they appear to have worked well compared to his previous attempts at a compensation balance.
A revolution in precision timekeeping
Around 1777 Arnold redesigned his chronometer to make it larger, probably to accommodate the new balance that worked with his pivoted detent escapement and patented helical spring. The first chronometer of this pattern was signed "Invenit et Fecit" and given the fractional number 1 over 36, as it was the first of this new design.It is generally known as "Arnold 36" and was in fact the first watch that Arnold called a "Chronometer", a term which subsequently came into general use and still to this day refers to any highly accurate watch.
The performance of this chronometer exceeded all expectations and proved to be extremely accurate when tested for thirteen months at the Royal Observatory, Greenwich
Royal Observatory, Greenwich
The Royal Observatory, Greenwich , in London, England played a major role in the history of astronomy and navigation, and is best known as the location of the prime meridian...
from February 1, 1779 to July 6, 1780. All the more remarkable is the fact that not only was it placed in several positions during the trial but even worn at some point and carried around.
During this period the timekeeping error was 2 minutes 32.2 seconds, but the error in the last nine months amounted to just one minute. The greatest error in any 24 hours was only four seconds, or one mile of Longitude.
Subsequently Arnold produced a pamphlet detailing the trial and the results with attestations of veracity from all those concerned with testing it, in charge of this was Maskelyne's assistant the Rev. John Hellins
John Hellins
John Hellins FRS was an autodidact, schoolteacher, mathematician, astronomer and country parson.-Early years:He was born in Devon ca...
.
The astonishing performance of this watch caused controversy because many thought the result either a fluke or a fix of some kind, particularly as Maskelyne
Maskelyne
Maskelyne is the surname of several people:*Nevil Maskelyne , the fifth British Astronomer Royal*Mervyn Herbert Nevil Story-Maskelyne *Nevill Maskelyne Smyth, served in the First World War 1914–18....
was effectively one of Arnold's patrons.
However, from the technical point of view the design was entirely sound and therefore proved highly accurate over long periods. Arnold evidently learned the lessons that Harrison had learned before him, By using a large, quickly oscillating balance (18,000 beats per hour) with small pivots. Arnold's detent escapement provided minimal interference with the controlling helical balance spring, since the temperature compensation was in the balance itself. this was suggested by Harrison as being a prerequisite, although he never developed this idea.
An important point concerning Arnold's pivoted detent escapement is that it did not need oil on the acting surfaces, with the advantage that the rate of going did not deteriorate and remained stable for long periods. At the time, the only oil available was vegetable in origin and degraded fairly quickly compared to modern lubricants.
This chronometer 60mm in diameter is housed in a gold case, and miraculously has survived in a perfect and original condition. It can be seen in the collections of the National Maritime Museum
National Maritime Museum
The National Maritime Museum in Greenwich, England is the leading maritime museum of the United Kingdom and may be the largest museum of its kind in the world. The historic buildings forming part of the Maritime Greenwich World Heritage Site, it also incorporates the Royal Observatory, Greenwich,...
, Greenwich
Greenwich
Greenwich is a district of south London, England, located in the London Borough of Greenwich.Greenwich is best known for its maritime history and for giving its name to the Greenwich Meridian and Greenwich Mean Time...
, London, having been saved for the nation in 1993.
In Britain prior to Harrison's marine watch, it seems to have been generally thought that a small or very small watch (Such as Arnold's ring watch) was the ultimate test of watch making skill especially with regard to complex watches and those built for accuracy. But both Harrison and Arnold had demonstrated that an accurate watch had to be of large diameter. So, by the end of the eighteenth Century, a large diameter watch was regarded as characteristic of a superior watch.
Arnold's second patent of 1782
In 1782, Arnold took out another patent; he did this to protect the latest and most important inventions, which were potentially lucrative. Several other watch makers most notably Thomas EarnshawThomas Earnshaw
Thomas Earnshaw was an English watchmaker who following John Arnold's earlier work, further simplified the process of marine chronometer production, making them available to the general public...
had started to copy Arnold's work, the latter around 1780 modifying his detent escapement by mounting the detent on a spring and creating the spring detent escapement
Escapement
In mechanical watches and clocks, an escapement is a device that transfers energy to the timekeeping element and enables counting the number of oscillations of the timekeeping element...
.
During the same period between 1779 and 1782, Arnold had finalized the form of his chronometer watches. As a result of continuous experimentation, he had worked out a way of making an effective but simple form of compensation balance and, at the same time, discovered a simple modification to his helical balance spring, which enabled it to develop concentrically and in addition conferred the property of isochronism on the oscillating balance. Not only this, but for adjustments to both the compensation balance and the balance spring could be carried out in a simple but calculated way. These were the main subjects of the patent, which he took out in 1782.
Concerning the balance, this consisted of a circular steel balance wheel to which two bimetallic strips were attached diametrically. Each bimetallic strip terminated with a screw thread on which was mounted a weight or balance nut. The further along the strip this nut was screwed, the greater the compensating effect. Another part of the patent concerned an addition to the form of the balance spring, this being a coil of smaller radius being made at each end of the helical spring, which offered an increasing amount of resistance to the rotating balance as it turned towards the end of each vibration. This was an important invention as it largely eliminated the problem of the positional adjustment of balance controlled watches. This device known as the "Overcoil Balance Spring" is still used today in most precision mechanical watches.
Another part of the patent concerned the escapement, this was a modification of Arnold's pivoted detent escapement which essentially mounted the detent on a spring. The specification only shows the part of this escapement, which is the method of impulse on the impulse 'roller'.
Patents and plagiarism
The fact that Arnold had greatly simplified the technology of the timekeeper with simple yet effective mechanical techniques also meant that these methods could be easily copied and utilised by other watch makers without permission, this is why Arnold took out his patents.There were two other makers also made precision watches with the detached escapement, both were friends of Arnold and both employed the highly skilled workman and escapement maker Thomas Earnshaw
Thomas Earnshaw
Thomas Earnshaw was an English watchmaker who following John Arnold's earlier work, further simplified the process of marine chronometer production, making them available to the general public...
. Emery used with Arnold's permission an earlier form of his compensation balance and helical balance spring, in conjunction with the detached lever escapement of Thomas Mudge
Thomas Mudge (horologist)
Thomas Mudge was an English horologist who invented the lever escapement, the greatest single improvement ever applied to pocket watches.-Early life:...
, and John Brockbank employed Earnshaw to make his pattern of chronometer but with Brockbank's design of compensation balance.
In 1780, while making these chronometers for Brockbank, Earnshaw modified the pivoted detent by mounting the locking piece on a spring thus dispensing with the pivots. He regarded this as a great invention, although, in fact, it was only a minor improvement. Arnold managed to see this new idea and promptly took out the 1782 patent for his own design of spring detent, but it is not known whether this preceded Earnshaw's own idea.
Therefore, there has been a great deal of debate over who was the inventor of the spring detent escapement, Arnold or Earnshaw. This argument, first initiated by Earnshaw has been continued by horological historians such as Rupert Gould
Rupert Gould
Rupert Thomas Gould , was a Lieutenant Commander in the British Royal Navy noted for his contributions to horology .-Life:...
even up to the present, none recognizing the fact that it was not any particular form of detached escapement, which led to Arnold's success but was due to his methods of adjusting the balance spring for positional errors. Arnold probably tried to keep these secret, it is recorded that he clearly expressed his concerns about possible plagiarism to Earnshaw, warning him not to use this particular form of balance spring.
Nevertheless, Earnshaw through another watchmaker Thomas Wright, took out a patent a year later in 1783, and included in the multiple specification was Earnshaw's pattern of integral compensation balance and spring detent escapement. However both of these were practically undeveloped and the balance especially had to be redesigned.
But importantly, because Arnold's balance spring patents were in force (each for 14 years) Earnshaw could not use the helical balance spring until the 1775 patent lapsed in 1789 and in the case of the 1782 patent, 1796. It is evident that until around 1796 Earnshaw made watches with flat balance springs only, but post 1800 practically every marine chronometer including those by Earnshaw had a helical spring with terminal overcoils.
Significantly, it is from this date that Earnshaw and others started to have any kind of success in producing successful marine and pocket chronometers. Early examples by Earnshaw even copy Arnold's style of engraved signature which includes the legend "Invenit Et Fecit" as well as a fractional number.
Arnold was the first to produce marine and pocket chronometers in significant quantities at his factory at Well Hall Eltham from around 1783, during the next 14 or 15 years he produced hundreds before he had any kind of commercial competition at all. The facts prove that authors such as Gould and Sobel to be quite incorrect in their assertion that there was commercial rivalry between Arnold Sr. and Earnshaw.
Arnold and Breguet
The important French watchmaker Abraham-Louis Breguet became a great friend of Arnold. In 1792 the Duke of Orleans met Arnold in London and showed him one of Breguet's clocks, and Arnold was so impressed that he immediately travelled to Paris and sought permission for Breguet to take on his son as his apprentice.. Arnold appears to have given Breguet carte blanche to incorporate or develop any of Arnold's inventions and techniques into his own watches.These included his balance designs, helical springs made of steel or gold, the spring detent escapement, the overcoil balance spring and even the layout of an Arnold dial design which Breguet incorporated into his own. These were made from engine-turned gold or silver, this pattern becoming the classic and distinctive "Breguet dial", which in terms of design are identical in layout to the enamel dials which Arnold had designed for his small chronometers, these first appeared in 1783.
Arnold also appears to have been the first to think of the concept of the Tourbillon
Tourbillon
In horology, a tourbillon is an addition to the mechanics of a watch escapement. Developed around 1795 by the French-Swiss watchmaker Abraham-Louis Breguet from an earlier idea by the English chronometer maker John Arnold a tourbillon aims to counter the effects of gravity by mounting the...
, this probably derived from his known work on the recognition and elimination of positional errors. In the Tourbillon
Tourbillon
In horology, a tourbillon is an addition to the mechanics of a watch escapement. Developed around 1795 by the French-Swiss watchmaker Abraham-Louis Breguet from an earlier idea by the English chronometer maker John Arnold a tourbillon aims to counter the effects of gravity by mounting the...
device, the balance and escapement is continuously rotated and virtually eliminates errors which stem from the balance not being perfectly balanced. Arnold seems to have experimented with this idea but died in 1799 before he could develop it further. It is known that Breguet made a successful and practical Tourbillon mechanism around 1795, but nevertheless he acknowledged Arnold as the inventor by presenting his first Tourbillon in 1808 to Arnold's son John Roger. As a tribute to his friend Arnold Sr. he incorporated his first tourbillon mechanism into one of Arnold's early pocket chronometers, Arnold No.11, this has an engraved commemorative inscription dedicating his gift to the revered memory of Arnold. This significant watch can be seen today in the British Museum's collection of clocks and watches.
By the time of Arnold's death in 1799 he was the most famous watch maker in the world, and his pre - eminence as the inventor of the precision chronometer was recognized by all.
John Roger Arnold
Arnold's son John Roger Arnold was born in 1769 and served an apprenticeship with both his father and the eminent FrenchFrance
The French Republic , The French Republic , The French Republic , (commonly known as France , is a unitary semi-presidential republic in Western Europe with several overseas territories and islands located on other continents and in the Indian, Pacific, and Atlantic oceans. Metropolitan France...
watchmaker Abraham Louis Breguet
Abraham Louis Breguet
Abraham-Louis Breguet or Bréguet , born in Neuchâtel in Switzerland, was a horologist who made many innovations in the course of a career in watchmaking in France...
. He became Master of the Worshipful Company of Clockmakers
Worshipful Company of Clockmakers
The Worshipful Company of Clockmakers is one of the Livery Companies of the City of London. The Clockmakers were formed by a Royal Charter in 1631. Originally, no person was allowed to sell clocks unless they were a member of the Company. However, such requirements have since been relaxed and later...
in 1817. From 1787 he and his father founded the company Arnold & Son. After his father's death in 1799, John Roger continued the business, taking into partnership John Dent
Edward John Dent
Edward John Dent was a famous English watchmaker noted for his highly accurate clocks and marine chronometers.He founded the Dent company.- Early years :...
between 1830 and 1840. After his death in 1843 the company was bought by Charles Frodsham
Charles Frodsham
Charles Frodsham was a renowned English watch and clockmaker. He took over Arnold & Co in 1843 at 84 Strand, London...
.
The brand name Arnold & Son used by a Swiss watch company has absolutely no connection to the original firm founded by John Arnold.