Portrait of Thomas Mudge by Nathaniel Dance painted in about 1772 (pic from coimages.sciencemuseumgroup.org):
Thomas Mudge was born in Exeter in late 1715 or early 1716, the second son of Zachariah Mudge (1694-1769), school master and clergyman, and his first wife Mary Fox (d. in or prior to 1762). Shortly after the birth of Thomas, the Mudge family moved to Bideford, where Zachariah had become headmaster of the grammar school - at which school Thomas Mudge received his early education. On 4 May 1730, on the instruction of his father and aged fourteen or fifteen, Thomas was bound apprentice to George Graham, the eminent clock and watchmaker of Water Lane, Fleet Street, London, who had trained under Thomas Tompion before then succeeding him in his business. The young Thomas Mudge would probably have been present when the famous John Harrison visited Graham’s workshop and he would also have benefited from Graham’s important work with different escapements (see later text below); Graham formed a very high estimate of his pupil’s ability.
In 1738, Thomas Mudge qualified as a watchmaker and gained his freedom of the Clockmakers’ Company. He now took lodgings and worked privately for a while, being employed by a number of important London retailers/watchmakers. One of the most famous watchmakers for whom Mudge executed work over this period was John Ellicott FRS. When Ellicott was requested to supply Ferdinand VI of Spain with an equation watch, Mudge was entrusted with the construction of the piece, although as was customary, the watch was branded with Ellicott’s name. Subsequently, while explaining the action of the watch to some men of science, Ellicott damaged it but found himself unable to execute a repair himself; the watch had to be returned to its maker, Thomas Mudge, for the damage to be rectified. Ferdinand of Spain heard about this incident, and being a lover of mechanical inventions, he now granted Mudge an open commission to construct elaborate and complicated watches. Over the years, Mudge was to make at least five watches for Ferdinand including a repeater watch with an alarm designed to fit at the end of a cane, which gained considerable admiration for its maker from the king.
Possibly the first ever perpetual calendar watch, this piece by Thomas Mudge, dating to about 1762 (in a later plain 50mm silver case) and with a ruby cylinder escapaement was sold at Sotheby's in the summer of 2016 for £62,500 or about $79,000. Details and further illustrations of this watch can be found at sotheby's.com/en/auctions/ecatalogue/2016/john-harrison-enduring/discovery-l16055/lot.28.html (pic from i.pinimg.com/originals) :
From the late 1740s and into the early 1750s, Thomas Mudge worked on developing a new form of escapement for portable timekeepers; at around the time of the death of his former master, George Graham, in 1750. In fact, in that latter year, Mudge took premises at 151 Fleet Street, and on 18 November, two days after the death of Graham, he began to advertise for work on his own behalf. This marks the beginning of a remarkable career, with Mudge rapidly acquiring a reputation as one of England’s outstanding watchmakers. On 27 October 1753, Mudge married Abigail Hopkins of Oxford, who died in 1789; the couple had two sons. Also during this period, Mudge formed an association with a former fellow apprentice, William Dutton, which led to a partnership by the early 1760s, with both names appearing on their productions. The firm is known to have supplied Dr Johnson’s first watch in 1768 and to have constructed a fine watch with temperature compensation for John Smeaton. Mudge also prepared a longitude timekeeper for the young Swiss astronomer Johan Jacob Huber, incorporating Huber’s idea of a constant force escapement. In 1765, Mudge, who was then acting as an expert for the Board of Longitude, published “Thoughts on the Means of Improving Watches, and Particularly those for the Use of the Sea”, and after he had retired from active business in 1771, Mudge was to devote much attention to marine chronometer development.
Highly important experimental table clock and lunar clock by Thomas Mudge (discussed in the text) in the British Museum, possibly the first timekeeper to incorporate a balance controlled lever escapement. Dating to c.1754, this clock may have originally been intended to be submitted as a marine chronometer but then felt by Mudge to not be good enough - the combination of timekeeping and lunar indication fits the contemporary debate at the time between those who felt that longitude at sea could be found by a timekeeper and those who believed in the use of lunar observations. It has been ascertained that the theoretical accuracy of Mudge's lunar gearing was extraordinary and the clock features a train-remontoire to impart a more constant force to the escapement plus pioneering use of brass and steel bimetallic strips to act as temperature compensation. Clock is 12 inches high and case is ebonised wood.(pics from media.britishmuseum.org and, bottom pic, BMimages.com)
At this juncture in my topic, the invention for which Thomas Mudge is most popularly known must be discussed - the detached lever escapement, mentioned obliquely above. Wikipedia leaves no doubt as to the importance of this invention or technical development: “The lever escapement, invented by British clockmaker Thomas Mudge in 1755, is a type of escapement that is used in almost all mechanical watches, as well as small mechanical non-pendulum clocks, alarm clocks, and kitchen timers”. … “Since about 1900 virtually every mechanical watch, alarm clock and other portable timepiece has used the lever escapement.” Whilst acknowledging the importance of the lever escapement and accepting that Thomas Mudge had a pivotal role in its early development, it cannot be said that Mudge was the sole protagonist in the invention process, nor was he the final arbiter in its improvement. With regard to crucial forbears of the detached lever escapement, it has to be mentioned that l'abbe Hautefeuille, in France, may have a valid claim to be the inventor of the very first lever escapement some time before, and independent of, Thomas Mudge, but his rack and pinion lever escapement failed to enter the horological mainstream; we also have to acknowledge the invention by George Graham in about 1715 of his dead-beat escapement. When it comes to the considerable work needed to “perfect” the lever escapement after Mudge, a number of important names in watchmaking must be credited, including Joshua Emery, Abraham-Louis Breguet, Peter Litherland, Edward Massey and George Savage.
At the time when Thomas Mudge began to develop a new type of escapement there were essentially two escapements commonly used in watches and other portable timekeeping devices - the verge and the cylinder, the latter invented by George Graham in 1725. The verge escapement was robust and suited to everyday use while the cylinder was more refined and suited to higher precision and greater accuracy. Both of these escapements had an inherent problem, however, in that whilst in motion, the oscillating balance controlling the timekeeper was in constant contact with elements of the escapement. This created frictions and interference that inevitably affected the timekeeping. A similar problem affected a third type of escapement used in England at about the same time as the cylinder - the duplex; this escapement was more accurate than the cylinder but more delicate.
In about 1715, George Graham had invented a new escapement for clocks that greatly reduced the operating angles during which the pendulum locked and unlocked the escapement and during which the pendulum was impulsed by the escape wheel. This new form of escapement, known as Graham’s dead-beat, was the germ from which Mudge developed his new type of escapement. Mudge retained many similarities to the dead-beat in the action of the pallets with the escape wheel, but interposed a lever between the escape wheel and the oscillating balance. At one end the pallets acted with the escape wheel and at the other the lever imparted impulse to the balance to keep it swinging. This revolutionary step went hand-in-hand with ensuring that the geometry of the lever was such that once the lever had given the balance its impulse it was not in contact with the balance and so the latter was free to oscillate undisturbed through the rest of its swing. Hence the name, “detached lever escapement”. Interestingly, in about 1748, at roughly the same time as Mudge commenced development of his detached lever escapement, Julien Le Roy (who Mudge knew personally), developed a second “free” escapement that was virtually frictionless and - the detent. However, this form of escapement was not well suited to the general run of pocket watches and their wearers and remained largely a precision (esp. Marine) chronometer escapement. The lever escapement had the disadvantage of requiring lubrication but the detent was more sensitive to outside disturbances and was not self-starting after winding (see Appendix for animation of a lever escapement).
Thomas Mudge made a drawing of his new lever escapement and later, a model; he also subsequently incorporated lever escapements in one or two small clocks. If we are looking for an iconic timekeeper announcing the introduction of the detached lever escapement, the British Museum holds an experimental table clock with lunar indication and lever escapement made by Thomas Mudge between about 1754 and 1759. This clock, which once belonged to Isambard Kingdom Brunel whose grandmother was Thomas Mudge’s sister-in-law, is notable not only for its use of the lever escapement but also for the incredible accuracy for the time of the lunar indication; the clock also has a tide indicator. Mudge added further refinements to the clock in the form of temperature compensation and a spring remontoire to provide a more constant driving force for the escapement. As for the incorporation of the detached lever escapement in watches, the first ever watch to contain Mudge’s new escapement came some years later, in 1769; known as Queen Charlotte’s Watch or “the Queen’s watch”. Mudge had become acquainted with Count von Brühl, ambassador-extraordinary from the court of Saxony, who then became an enthusiastic and supportive patron. Through this association, Mudge achieved the sale to George III in 1770 of a gold watch incorporating his detached lever escapement. This watch, which also featured the first use of temperature compensation in a watch, was presented to Queen Charlotte, and later became part of the Royal Collections where it survives to this day. The watch itself is in 22 carat gold, measures 5.7 cm in diameter and is surprisingly thin. I have included a couple of pictures of Queen Charlotte's Watch but the best visual account is a video from the Royal Collections Trust showing the watch in action, including the workings of Mudge's lever escapement. This video is easily accessed by going to vimeo.com/99220922.
The important and famous Queen Charlotte's Watch by Thomas Mudge (see text above) (pics from timezone.com):
Having gained some experience in applying his lever escapement, Mudge recognised both the difficulties involved in its implementation and its significance in terms of horological advancement. In a letter to Count von Brühl he said, “… it has this disadvantage, that it requires a delicacy in the execution, that you will find very few artists equal to, and fewer still that will give themselves the trouble to arrive at; which takes much from its merit.” Then, in the same letter, he states that, “If well executed, it has great merit, and will, in a pocket particularly, answer the purpose of timekeeping better than any other at present known.” It is ironic that the use by Mudge of his own lever escapement in watches came too late in his career for him to undertake its further development, and on his retirement and subsequent involvement with chronometers, Mudge left the lever escapement behind, for others to later pursue.
In 1771, Thomas Mudge quit active business due to ill-health and retired to Plymouth to be with his brother, Dr John Mudge. His other brother, composer Richard Mudge, had died in 1763). This period of retirement enabled Mudge to devote time and energy to his self-proclaimed, “hobby horse”, the improvement of chronometers designed to determine longitude when used in conjunction with a sextant. However, von Brühl recognised Mudge’s achievement and in about 1779 he persuaded Josiah Emery to make a watch with a lever escapement, giving him access to the model made by Mudge. Emery completed his first lever watch in 1782, which differed in certain respects from the Mudge model. He subsequently collaborated with Richard Pendleton in the making of about thirty lever watches, a number of which survive today and some of which were converted by Emery to his own, later, form of lever escapement. Emery always favoured the “straight line” arrangement, where the balance staff, pallet and escape wheel arbors are in line, as opposed to Mudge’s right-angled layout. In his earlier form, Emery used Mudge’s arrangement of two impulse cams located on the staff on different levels, and these engaged with pallets on the lever fork which were at correspondingly different planes. Later on, Emery used a single cranked roller on the staff which received impulse from the fork, this being in the same plane as the lever.
A yellow gold pocket watch by Thomas Mudge & William Dutton, 1771, with inner and outer case as well as pendant made in 1802 for the watch. Gilded movement under signed dust cover, chain and fusee, pierced and engraved balance cock with diamond endstone, large brass escape wheel (video from youtu.be/wpmvkm1cFIA):
It is tempting at this stage in my topic to proceed with an account of further experiments with, and developments of, the lever escapement between about 1785 and 1805 executed by a number of watchmakers based in London, followed by details of the vital work done by Staffordshire watchmaker Edward Massey, who in 1814 invented a form of lever escapement from which the classic English lever was eventually to emerge. However, that would be inappropriate in a biographical topic of limited dimensions. What is important to stress here is that although the role of Thomas Mudge in the invention and development of the lever escapement was important, it almost came prematurely and hinged to some extent on his own exemplary skills as a watchmaker. It was to be many years after Mudge, and work from many quarters, before the English lever escapement would become a standard pocket watch escapement. It would be 1850-60 before the lever watch had practically ousted the duplex and chronometer pocket watch. The cylinder escapement had been ousted some time before in Britain (though the Swiss continued with an inexpensive cylinder watch for a long period of time) and the verge escapement lasted in production in England until the 1880s. As for Thomas Mudge himself, retirement in 1771 essentially meant the end of his own use of the lever escapement in watches.
Returning to the biography of Thomas Mudge, we now come to his so-called “retirement” from 1771, and his involvement in the creation of marine chronometers. As far back as 1714, the government had offered a reward of £20,000 for a means of determining longitude within 30 geographical miles. £10,000 could be awarded if the accuracy was within 60 geographical miles. John Harrison (1693-1776) ultimately won the £20,000 in 1773 for the performance of his fourth timekeeper.
In spite of Harrison’s success, further rewards were offered for a more perfect method of determining longitude, and Mudge was confident that he could succeed in attaining the degree of exactness required. In 1776, not only was Mudge appointed Watchmaker to the King but he also completed his first marine chronometer and successfully had it tested by Thomas Hornsby, Savilian Professor of Astronomy at Oxford. This chronometer was then submitted to Nevil Maskelyne, Astronomer Royal, for extended tests at the Observatory (1776-7) which it failed to pass; it eventually was housed in the British Museum. Mudge's first chronometer featured an eight-day movement powered by two separate springs in a single barrel and in spite of Maskelyn'e rejection it turned out to a a highly accurate chronometer reemaining a landmark in timekeeping accuracy until the 1880s. The Board of Longitude meanwhile gave Mudge 500 guineas and urged him to make another watch in order to qualify for the government’s rewards, the terms of which required the construction of two watches of the specified accuracy. Mudge now set about making two more timekeepers which were so alike that they were named after the colour of their shagreen cases, the“Green” and the “Blue”. These two chronometers had a power reserve of 36 hours and featured enamel dials set in filigree work; the finish was superb in spite of the fact that Mudge’s eyesight was failing at this stage in his life. Subsequent to public testing, these watches were also deemed by the Astronomer Royal as not satisfying the terms of the reward.
Thomas Mudge's first marine chronometer, c.1774-76, - see text and further details at vergefusee.com/watches-and-movements-by-century/18th-century/ (pics from vergefusee.files.wordpress.com):
The Thomas Mudge "Green" and, on the right, "Blue" marine chronometers - see text (pic from vergefusee.files.wordpress.com):
The rejection by Maskelyne of the Mudge marine chronometers became the subject of controversy; it was claimed that Maskelyne had not given the timekeepers a fair trial, and that they had worked better in other hands both before and after the period of Maskelyne’s observation. It has been said (Bruton (1979)) that by the time of the last trials (1789-90) Thomas Mudge was suffering from “senile decay”, but whether or not that is true, In June 1791, Mudge’s eldest son, also named Thomas and a London lawyer at Lincoln’s Inn, became involved in his father’s case. He presented a memorial to the Board of Longitude stating that although his father’s timekeepers had not been adjudged to go within the limits defined for reward, they were superior to any hitherto invented, and were constructed on such principles as would make them permanently useful; thus, their maker should be considered for some financial recognition for his labours. The memorial proved unsuccessful, so Thomas Mudge Jr carried a petition to the same effect to the House of Commons, and a committee was appointed consisting of Pitt, Wyndham, Bathurst, and Lord Minto, to consider the value of Mudge’s invention.
Mudge’s case was also put strongly by son Thomas, a London lawyer at Lincoln’s Inn, in a pamphlet of 1792 entitled, “A narrative of facts relating to some timekeepers constructed by Mr. T. Mudge for the discovery of the longitude at sea, together with observations upon the conduct of the astronomer royal respecting them”. Maskelyne immediately retorted by means of a pamphlet of his own, “An answer to a pamphlet entitled A narrative of facts … wherein … the conduct of the astronomer royal is vindicated from Mr. Mudge’s misrepresentations”. The final repost came from the younger Thomas Mudge, still in 1792, with his “Reply to the answer … to which is added … some remarks on some passages in Dr. Maskelyne’s answer by his excellency the Count de Bruhl”.
Mudge was supported throughout by F. X. DeZach, astronomer to the Duke of Saxe-Gotha-Altenburg, who had observed the variations of the first Mudge marine chronometers for two years, and by Admiral John Campbell, who carried the chronometer on voyages to Newfoundland in 1785 and 1786 respectively. This chronometer was afterwards stated by the younger Thomas Mudge to vary less than half a second in 24 hours. Interestingly, John Harrison had previously also had similar grievances against Maskelyne and the Board of Longitude, believing that the Astronomer Royal favoured the use of lunar tables rather than chronometers for finding longitude and was therefore inclined to be overly severe in his judgement and testing.
Some final recompense was achieved for Thomas Mudge and his marine chronometers when the House of Commons committee, having been assisted by various eminent watchmakers and men of science, finally voted Mudge the sum of £2,500. Two years after receiving this award, Thomas Mudge died on 14 November 1794 at his son Thomas’s house in Newington Butts, Surrey. He was buried on 21 November at St Dunstan-in-the-West, London. His younger son, John (1763-1847) was presented to the living of Brampford Speke, near Exeter, by the lord chancellor in 1791 on the recommendation of Queen Charlotte.
A Thomas Mudge and William Dutton silver-cased (51mm) quarter repeating pocket watch originally with a cylinder movement, then converted to lever escapement, signed and numbered 1408, c.1770. With finely engraved and pierced balance cock and plate, diamond endstone and blued screws. Five round pillars and signed gilt brass dust cap. The silver case dates to 1896 and the enamel dial and blued spade hands are also later replacements, as is the re-drilled bell (pics from antiques-atlas.com):
The main sources used in drawing up the topic text, in descending order of importance are as follows:
“Mudge, Thomas (1715/16-1794)” by Thomas Seccombe, revised by David Penney; Oxford Dictionary of National Biography, 2004.
“Thomas Mudge’s Experimental Lever-Escapement Clock” by David Thompson; A History of Time, QP magazine, date not known.
“The Camerer Cuss Book of Antique Watches” by T. P. Camerer Cuss - Re-illustrated, revised and enlarged by T. A. Camerer Cuss; Antique Collectors’ Club, Woodbridge, Suffolk, 1976.
“The History of Clocks and Watches” by Eric Bruton; Orbis Publishing Ltd, 1979 (1989 reprinted edition; Black Cat, Macdonald & Co)
Wikipedia articles on Thomas Mudge (horologist) and the Lever Escapement.
“Timepieces: Masterpieces of Chronometry” by David Christianson; David & Charles, Newton Abbot, Devon, 2002.
“The British Museum Watches” by David Thompson; British Museum Press, 2008 and 2014 (2014 edition).
Volker Vyskocil animation of a basic lever escapement (animation from momentousbritain.co.uk/go/Mechanical_Clocks