Lighthouses: The Race to Illuminate The World

By Toby Chance and Peter Williams

The Great Exhibition, Crystal Palace, 1851: James Chance, of the glass-making firm Chance Brothers, is nervously showcasing a new lens, that, unknown to him, will revolutionise lighthouse production, propel his family business into a position of world leadership, save countless lives and have far-reaching consequences for trade, empire and the map of the world.This is where "Lighthouses" begins. The true-life story that follows is of one man and his family's unexpected role in an exciting race to perfect this technology, against European rivals and colleagues, as they strive to regain for Britain the leadership position she had lost to the French in the 1820s.This fascinating story places James Chance and the Chance Brothers firm against the backdrop of a time in which lighthouse manufacture was transformed from a craft into a scientific, high-precision industry. As a tool for globalisation, and with immense strategic and economic value, lighthouses helped to establish a network of communications that transformed the trade maps of countries and empires.

• Language: English
• Publisher: IMM Lifestyle Books
• Release date: Sep 26, 2008
• ISBN: 9781780091044

Toby Chance

Toby Chance is James Chance's great-great-grandson and grandson of Sir Hugh Chance, the last Chairman of an independent Chance Brothers. Toby works in event management and communications and has spent the past three years researching the family history.

Book preview

Prologue

The workmanship was not characterised by any degree of finish – a fact in its favour, as any great degree of finish, or adoption to ornament, would involve an increased outlay of capital without compensating advantages.

Report of the Great Exhibition jurors on James Chance’s first lighthouse lens, 1851

The use of light to guide the mariner as he approaches land, or passes through intricate channels has, with the advance of society and its ever increasing interests, caused such a necessity for means more and more perfect as to tax the utmost powers both of the philosopher and the practical man in the development of the principles concerned, and their practical application.

Michael Faraday, 1860

The lens rose 20ft (6m) above the exhibition floor, standing aloof, its green tinge giving no hint of the power of the light it was designed to emit. Four hundred and thirty prisms held in place by a gun-metal framework formed a complex array of glass and steel weighing four tons, at whose function visitors to the exhibition could only wonder. As they strolled past and looked up, faces contorting into expressions of curiosity and non-comprehension, one man stood in the background bearing a more knowing countenance. To him it was a miracle the lens was even there. He had conceived of the notion of building it six years earlier but put it off for a further five years, such was the technical challenge. In England only two or three firms had made the attempt, but had given up in the face of the punitive excise duties on glass and the superiority of French competition. James Chance, though, was a determined man and had the backing of the greatest glass manufacturer in England, as well as the moral support of men of science, who bore a heavy grudge against their French rivals.

The Great Exhibition of 1851 was the ideal stage on which to unveil his brainchild. Eight million people from all over Britain walked through the maze of halls that displayed the products and inventions – more than half of them British – of countless workshops and factories around the world. Most of them had never been revealed to the public before, and Queen Victoria herself was amazed at the ingenuity of her subjects. Writing in her journal on the evening of the opening on 1 May 1851, she described her feelings of elation:

The tremendous cheering, the joy expressed in every face, the vastness of the building, with all its decoration and exhibits, the sound of the organ (with 200 instruments and 600 voices, which seemed nothing), and my beloved husband, the creator of this peace festival ‘uniting the industry of all the nations of the earth’, all this was moving indeed, and a day to live for ever.

James Chance was proud of his lighthouse lens, as his uncle Lucas Chance was proud of the building that housed it. Under his direction, the firm of Chance Brothers of Birmingham had, in less than six months, manufactured the 300,000 glass panes that gave their name to the building that Punch had scoffingly christened ‘the Crystal Palace’. As W.A. Thorpe wrote in his authoritative 1961 book English Glass, the ‘Crystal Palace was the greatest work of glass we have ever possessed, and unequalled as an architectural use of the material’. The scale of both achievements was symbolic of the age. Chance’s mass production of the glass proved it was possible for industry to ratchet up production to meet the huge demand generated by population growth and exports to an expanding empire. The lighthouse breakthrough came just at the time when steam ships swelled world trade and the Admiralty needed safer waters through which the Royal Navy could sail to protect this trade and pursue the country’s military adventures.

In 1851, James Chance was 37 years old and senior manufacturing partner at Chance Brothers. He had little experience of the sea, having taken the short trip across the English Channel but half a dozen times, and had never even imagined taking an ocean-going voyage. But something gripped his imagination and mathematical inclinations, and he devoted the next 30 years of his life to the science of lighthouse optics, engineering and manufacture. During this time he was consulted by eminent men such as Michael Faraday, Sir David Brewster, Charles Babbage, Sir George Airy, Sir James Douglass and the lighthouse Stevensons. His contribution to the work of the Royal Commission on Lighthouses, Buoys and Beacons between 1858 and 1861 helped restore England’s position at the forefront of lighthouse design and engineering, which it had lost to France in the 1820s. In 1901, a year before his death, he was awarded a baronetcy in Queen Victoria’s birthday honours list for services to the seafarer. By 1951, when Chance Brothers celebrated its centenary at a glittering dinner at the Savoy Hotel, the company had supplied more than 2,400 lighthouse lenses and hundreds of complete lighthouse structures to nearly 80 countries.

But no family, and especially no family business, is without its tensions, squabbles and sometime irreconcilable differences. Lucas Chance, James’s uncle – impetuous, irascible and driven by an obsession to outwit his rivals – was the undisputed front man at Chance Brothers from 1822, when he founded the business, until close to his death in 1865. He brought his younger brother William, James’s father, into the business when the firm was expanding and needed an injection of capital. William had built a successful trading business in Birmingham and was High Bailiff of that town in 1830, but Lucas needed him to bolster the family presence within his firm.

James, William’s eldest son, was likewise compelled to join the firm, not through his inclination for business, but rather because he felt it his duty to support his father and uncle. It was only once he realized the glass business held the promise of scientific and engineering experiment that he found his own niche in the lighthouse works. Lucas was continually looking for ways to expand the business and always had an eye for the bottom line. James was more interested in the scientific and engineering aspects of glass manufacture, and for much of its life the Chance Brothers lighthouse business was more of a drain on profits than a contributor.

Two of the chief motivators for businessmen in the 19th century were economic gain and patriotism. In James’s case, he chose in lighthouses a product that paradoxically brought little of the former but satisfied the latter in great measure. Lighthouses were intrinsically ‘good’ and fitted well with James’s character of uncompromising integrity and reliability, combined with his desire for truth, to do good works and to leave a legacy for the community. What is incontestable is that the lighthouse works was the embryo that spawned the plethora of innovations and products which, by the early 20th century, had given Chance Brothers a reputation for excellence.

Perhaps James Chance’s greatest legacy to the firm and to British industry was his unswerving commitment to the application of science and engineering to manufacturing. In the commemorative volume Mirror for Chance, published in 1951 to celebrate the centenary of his founding of the lighthouse works, the index of products made in the Chance factory reads like a compendium of British ingenuity and innovation. From antique glass, airport beacons and ashtrays to Britannia domestic glassware, deep-well pumps, fluorescent lighting, fog signals and laboratory tubing, to microscope slides and lenses of every description, lighthouse optics, petrol-pump globes, stained-glass windows, television tubes and X-ray bulbs, there was nothing the firm could or would not attempt to invent, build or improve on in the pursuit of engineering innovation and perfection.

Lighthouses – the untold story

Most books written about lighthouses dwell on how they were built and skim over the main reason for their existence – the light they produced. This is why the names Stevenson, Smeaton and Douglass are better known than Fresnel, Chance and Brewster among the general public. The first three were principally civil engineers whose work is very visible in the structures they erected in prominent parts of Great Britain. Their heroic status is deserved for the incredible feats of engineering they undertook, which stand out as lasting monuments of engineering accomplishment. The other three, by contrast, spent their time in the workshop and laboratory, not on wind-blasted headlands directing building crews against the worst the elements could throw at them. All three were optical scientists (one, James Chance, was an accomplished engineer as well) whose work, ironically because of its focus on light and vision, was less obviously visible and comprehensible to the untrained eye. But this does not mean their contribution to lighthouses was any less significant than the first three honourable gentlemen. The lighthouse lens with which these men are indelibly associated was the fundamental illuminating technology for more than 150 years, even when the candlepower of burners increased with each successive generation of technology. This book shifts the emphasis from construction to illumination, and looks at how the light from a lighthouse was produced and magnified, and how lighthouses proliferated on a gigantic scale in the second half of the 19th century.

Lighthouses have always fascinated people for their often incredible feats of engineering and construction, the romance of their association with shipwrecks, disaster and feats of heroism, the loneliness and dedication of the lighthouse keepers, and the beauty of their locations, which have inspired countless paintings and photographs. But there are parallel stories of equal interest and importance, hitherto neglected by writers and historians, in which other heroes and villains come to light and make their mark. How the English lighthouse authorities were embarrassed into action by their Scottish and French counterparts, which employed both better scientific minds and more advanced technology to protect life and property at sea. How lighthouses became the backbone of a global network that facilitated trade, just as the telegraph facilitated the transfer of information. Together, the lighthouse and the telegraph were the fibre-optic cable and satellite networks of today. And, in a world where the physical movement of goods and people was the first driver of 19th-century globalization, their efficient and safe transport was imperative. The lighthouse was an indispensable technology of 19th-century imperialism, and this book attempts to uncover how this came to be, through the contribution of a few great minds and James Chance in particular.

British–French rivalry

Of the aforementioned optical scientists, Augustin Fresnel was French while Brewster and Chance were British. Fresnel achieved fame in the science of lighthouse illumination ahead of his British rivals because he was connected to the French lighthouse nexus, while the other two were not, and it was in France that the dioptric lens was first employed. The rivalry between France and Britain in the science of lighthouses is thus a theme running throughout this book.

It was only through co-operation and competition – both benign and ruthless – with French lens makers that Chance Brothers was able to reach a pre-eminent position by the 1860s. French and later Swedish and German manufacturers were the firm’s principal competitors in the lighthouse business, while in glass manufacture the French, notably St Gobain, were again prominent, and at home Pilkington’s was the emerging leviathan. As the home of dioptric lenses, France maintained its dominance through the combined efforts of at least eight firms – François Soleil, Jean Jacques François, Louis Letourneau, Henry-Lepaute, Sautter-Harlé, Barbier et Fenestre, Barbier et Bénard and Barbier, Bénard et Turenne. In Scotland, preeminent (in fact solitary) was the Stevenson family, while the enormous US market was at first supplied by American and later by French manufacturers. That Chance Brothers supplied only a handful – perhaps 15 first- to fourth-order lights in all – of lenses to America is due to the close relations maintained between US maritime authorities and the French (France’s military and diplomatic support for the Colonies in the War of Independence was not forgotten) as well as to the inability of Chance’s to establish capable agents in New York and Washington. Chance Brothers nevertheless competed successfully in the traditionally French-dominated territories of Russia and the Black Sea countries and even supplied 23 lights to France.

At the turn of the 19th century, British lighthouses were the pride of her navy, merchants and the lighthouse administrators in London, Edinburgh and Dublin. Trinity House, which controlled the lighthouses of England and Wales, was the oldest and most respected lighthouse authority in Europe, and British shores were better protected by lighthouses than any other country. But 50 years later a vastly different picture had emerged. In 1858, Parliament was forced to appoint a Royal Commission to investigate the status of Britain’s and her empire’s lighthouses, buoys and beacons, which had come in for scathing criticism by both her naval and merchant seafarers. The critics were particularly contemptuous of the lighthouse systems of England and Wales and those of the Colonies, while Scotland, under the direction of the Stevenson’s, engineers to the Commissioners of Northern Lights, came off more lightly.

England had ceded leadership to her arch enemy France, not only in administration, but also as the recognized authority on lighthouse science and engineering. Britain’s industrial and maritime supremacy was felt across the globe, yet her commitment to protecting her seamen and merchant fleets from shipwrecks was far from evident. In France, lighthouses were the beneficiary of a strong relationship between the scientific community and government. The French lighthouse authority was highly centralized, with most lighthouses under state control. So, when a brilliant optical scientist, Augustin Fresnel, invented a new method of illuminating lighthouses using lenses, it was immediately applied to nearly all French lighthouses. In Britain, the worlds of science and government endured an awkward relationship, with less state patronage for both scientists and their institutions. Trinity House was a guild operating under its own ancient royal charter and the Elder Brethren who ran it jealously guarded their independence from government. They were sceptical of science, with not a single recognized scientist occupying a senior post. Unlike in France, British lighthouses were mainly in private hands, a source of profit for their owners who charged fees to passing ships. In short, the French lighthouse system was rooted in science, hierarchical, regulated and unified, while in Britain it was split between a conservative institution run by retired seamen and lighthouse entrepreneurs who resisted interference from London.

This is why the revolutionary lighthouse lens introduced in 1822 has ever since been named after a Frenchman, Augustin Fresnel, though Scotsman David Brewster had a valid claim to be its true inventor. In 1812, Brewster invented a lens almost identical to Fresnel’s, but its potential for lighthouse illumination wasn’t recognized by Trinity House, if it knew about it at all. Fresnel was lauded as a hero of science in his home country; Brewster was an outsider whose temperament upset the establishment and whose early insight that lenses would transform lighthouse illumination was ignored by the authorities. After Fresnel announced the new technology, Trinity House and the Northern Lighthouse Board failed to follow the lead of their French counterpart for more than 15 years. Trinity House only appointed a recognized scientific advisor in 1835, and chose an experimental chemist – Michael Faraday – when all the attention across the Channel was on the science of optics. Michael Faraday’s experiments with optical glass in the early 1830s had been a signal failure, so if Trinity House wanted to promote lens manufacture in England, Faraday’s appointment was a strange way of going about it.

It was not until the 1858 Royal Commission discovered James Chance that the importance of optical science was finally recognized in Britain, and she began to regain her pre-eminence in lighthouse illumination. The intervening 40 years were a time of procrastination in Britain, while in France the new lens technology was quickly adopted. The Stevenson’s, after much prevarication, also adopted it but relied on French manufacturers for most of their supplies. One English firm, Cookson’s of Newcastle, tried to emulate the French, but their lenses were shoddy by comparison. Chance Brothers entered the business in 1851 but it took them 10 years to perfect the technology. James Chance was the only man in Britain who was able first to equal and then surpass the French in the design and manufacture of lighthouse lenses. He combined four branches of engineering – optical, mechanical, electrical and civil – into one to create the modern lighthouse-engineering discipline. These were in turn fused with Chance Brothers’ manufacturing muscle and commercial drive to establish the greatest force in the world lighthouse industry. This was a major breakthrough that changed the manufacture of lighthouse illumination equipment in Britain from a back-street metalsmiths workshop into the large industrialized glassmakers works found at Chance Brothers.

The lighthouse – a tool of empire

To place this account into its historical context we must also look at the influences that created the conditions first for James Chance to reach this prominent position and then for lighthouses to take their place, alongside the telegraph, the railway and the steamship, as one of the ‘tools of empire’, which Britain mastered faster and better than any other country until the start of the First World War. Among these influences are the religious, scientific and educational conditions predominating in Britain and France in the early 19th century; the interrelationships between science, business and government; the part played by the wave of social and economic reform (and revolution) that swept through Europe as it left behind a time of conflict and entered a 100-year period of relative peace; and lastly the forces of family, individual ambition and talent that propelled Europe from the scientific into the industrial age.

The backdrop to our story is the incredible expansion of British and European influence across the globe in the ‘long 19th century’, which runs from the introduction of steam powered manufacturing in the 1780s to the outbreak of the First World War. By 1914, Britain controlled more than one third of the world’s population, and its navy and merchant fleet could be found in every major port on six continents. Africa had been colonized by Britain, France, Germany, Portugal and Belgium; most of south Asia, the Far East and Australasia was under European control, as was South and Central America. North America had been colonized, and though the United States had gained independence from Britain in 1776, it was still a colonizing power with European roots. The two great Eastern civilizations, Japan and China, could not stand aloof from the European orbit and were forced to adopt its technology to avoid being rendered commercially, diplomatically and militarily irrelevant.

Historians have written about the central role railways, steamships, the telegraph and even quinine played as Europe established domination over societies that had not industrialized. There are passing references to lighthouses as another tool of empire in the standard historical texts, but none of them give due recognition to their significance in opening up new territories and making them safe for the colonizing powers. Without the proliferation of lighthouses into every port and major navigable water, losses at sea would have continued to mount and the navigation of faster, heavier and bigger steamships would have been an extremely hazardous business. The erection of a lighthouse accompanied the construction of new harbours, and it was invariably pressure from local interests that led to their construction. The governors and city fathers of Sydney, Singapore, Cape Town, Boston, Shanghai and Karachi all had one thing in common: they understood that without a safe port, illuminated by a network of lighthouses both in the harbour and the approaches to it, their cities would be a far less attractive destination for merchants and traders than those that possessed them. Because they invariably did not possess the means to build a modern lighthouse themselves, they had no choice but to order it from the colonial power. Lighthouses were under the control of the Admiralty, the Boards of Trade or their equivalents in Britain and most other countries, and these notoriously conservative institutions were under constant pressure to accede to the demands of impatient proconsuls in faraway places to supply them with these essential tools.

CHAPTER 1

Lighthouse Illumination Before 1823

… and so we must now proceed to explain also the nature of glass …

Pliny the Elder (AD 23–79)

The history of lighthouses is intimately associated with the history, composition and manufacture of glass – thus it is essential that we take a quick survey of the development of this most versatile of materials.

Glass in its simplest form is a noncrystalline substance made from a fused mixture in the approximate proportions of 55 per cent silica sand, 25 per cent soda ash (in the early days potash) and 20 per cent lime. The solid translucent material is formed from the molten state by rapid cooling that prevents the formation of crystals. The colour of glass made from naturally occurring sand is green to bluish green, which is caused by iron and other impurities. Glassmakers learned to make coloured glass by adding metallic compounds and mineral oxides to produce brilliant hues of red, green and blue. Though coloured glass was used for decoration, for example stained-glass windows in churches, lighthouse lens makers quickly realized that coloured glass could be used to give a red or green characteristic to a white light, by placing a sheet of coloured glass in front of a clear lens, a technique that is still in use.

Glass has existed in one form or another since prehistory, not always man-made, but also formed naturally by volcanic action, when the erupting lava flow cooled too rapidly for there to have been time for crystals to form. This form of glass is called obsidian, and is usually black due to impurities. Stone Age people are known to have used it to make sharp knives and spear points as the noncrystalline structure allowed it to be honed to a sharp edge, and it is still used today for surgical scalpels. Early glass was a valuable commodity known to have been used as early as 3000 BC for beads, seals and decorations. While a date for the invention of man-made glass has never been established, there is a tradition that, around 1000 BC, the crew of a Phoenician ship carrying a cargo of nitrum – a type of hard, dense rock salt – dropped anchor off a sandy beach and, finding no stones, used lumps of their nitrium cargo to support the cooking pot. The heat of the fire caused the nitrium to fuse with the sand to form a translucent liquid. In Egypt, small bottles were made by winding a glass thread round a bag of sand and heating it at the same time to fuse the threads together. When the desired thickness and shape had been formed the bag was cut and the sand removed. The first cast glass was also ancient Egyptian in origin, made by pouring molten glass into a mould. By the first century BC, the technique had travelled to Greece and other trading centres around the Mediterranean.

At the start of the Christian era, methods of glass blowing were discovered as the craftsmen of the Roman Empire developed many new ways of working with glass. The Roman conquests and the influence of Roman culture spread the use of glass objects and techniques as far as Britain and Northern Europe. The major centres of glassmaking were now at Alexandria, Egypt, Byzantium (Constantinople, now Istanbul) and in the German Rhine Valley. New processes, such as staining, gilding and enamelling were developed as were new products, such as translucent and stained-glass windows, pipes and vases. In Europe during the Dark Ages, the use of glass declined, with many methods of manufacture and finishing being forgotten. However, glass was not entirely abandoned in Northern Europe, as it was known to have existed in Anglo-Saxon times. There was a revival in the 7th century but the ‘Golden Age of Islam’ led to the next major development, the first clear, colourless, high-purity glass.

The Muslim chemist Abbas Ibn Firnas (AD 810–87) perfected the technique of producing clear glass, his glass described by the Baghdad poet Al Buhturi as follows: ‘Its colour hides the glass as if it is standing in it without a container.’The coloured or stained glass so much used in Christian church architecture was made from nearly 50 recipes for different colours published by Jabir ibn Hayyan in the 8th century. By the 10th century, the sun was being harnessed as a heat source, with Ibn Sahl first describing the refracting parabolic mirror made from glass to intensify and concentrate the sun’s rays into a crucible furnace. As William the Conqueror was planning to invade England in 1066, glass makers in Northern Europe were moving forward from the Mediterranean soda glass produced by heating pebbles and charcoal to a mixture of lime, sand and potash. European glass was now significantly different from glass produced in Mediterranean countries. In Germany, a method of making sheet glass was invented, a method that was, with refinements, to remain in use until the mid-19th century. Molten glass was blown into spheres, which, while still hot, were swung to form cylinders that were cut and flattened before they cooled.

A variation of this method, developed by the Venetians, was called crown glass. This was used for glazing windows. To make the panes, the glass was first blown into a hollow sphere that was then reheated and spun to form a large disc about 5ft (1.5m) in diameter. This disc was then cut into panes, the clearest and thinnest glass cut from the edge of the disc, progressively getting thicker and more opaque towards the bullion or bull’s eye. Large good-quality windows were made by setting the small diamond shapes taken from the edge of the glass into a lead lattice frame. The bull’s eye and centre glass were used up on smaller windows. These lead-framed windows are still found in churches and older houses throughout Europe and North America.

In the manufacture of glass, two ingredients – sand and furnace fuel – have to be sourced as near as possible to the glassmaker’s furnace to make the product economically viable. In England, the first furnaces were located in Sussex, near to the major markets of London and Paris, and where they were able to utilize local timber and silica sand. However, the huge amount of timber consumed led to King James I banning the use of timber, forcing the glassmakers to move near to another source of fuel: the coal-mining districts in the North East, West Midlands, Lancashire and Bristol areas, where suitable sand and limestone were available within a cost-effective distance.

Though sand can be fused at very high temperatures, in the region of 2,000ºC (3,632ºF), in order to form glass it was found that the addition of potash and limestone not only improved the quality of the glass, but also lowered the temperature needed for fusion. Potash occurs in some parts of the world naturally, where it is mined, but most supplies in northern Europe were sourced from a cottage industry that burned broad-leaved timber or kelp. In the United States in 1790, Samuel Hopkins patented an industrialized method of making potash, but hitherto burning wood enclosed in barrels and leaching water through the resulting ashes had been the usual method. In coastal communities, notably the west coast of Scotland and Spain, seaweed was substituted for wood. By the 1800s, potash supplies, both in quality and quantity, were not keeping abreast of demand. Nicolas Leblanc, a French chemist, invented a process to manufacture soda ash by heating a mixture of salt, limestone and sulphuric acid. This process was highly toxic, and along with the soda ash ‘cake’, it left a residue of hydrochloric acid and hydrogen chloride gas. The former polluted watercourses in the neighbourhood of the manufacturing plant while the latter destroyed the vegetation. By the 1860s, glassmakers had changed to a more environmentally friendly process invented in Belgium by Ernest Solvay.

Optical glass

Optical glass starts as a pot of glass, which is left to cool very slowly to obtain the required homogeneity. Early work to produce good quality optical glass was carried out by a Swiss woodcarver, Pierre Louis Guinand, in 1768. By 1775, he was able to demonstrate lenses for telescopes, using a composition of flint glass (combining sand, potash and lead oxide), which was heated and stirred in ways that reduced the striations (lines) in the glass, thus improving its optical qualities. Shortly before Guinand’s death, he negotiated unsuccessfully with the French government for assistance and his work went nowhere, though importantly he did leave detailed records that were later to prove crucial to Chance Brothers. Beginning in the late 18th century, Britain had lost its lead in the manufacture of telescopes to Germany. Here, the work of Joseph von Fraunhofer in centralizing the manufacture of glass and instruments along scientific lines between 1805 and 1825 was not matched by the English opticians, who did not have a reliable supply of optical quality glass. The efforts of English opticians W.V. Harcourt, G.G. Stokes and others to rectify this proved fruitless. Michael Faraday related in 1829 how the English optician John Dollond ‘had not been able to obtain a disc of flint glass four and a half inches in diameter, fit for a telescope, within the last five years, or a suitable disc of five inches in diameter within the last ten years.’ The testimony of Sir George Airy, Astronomer Royal, is further evidence of the difficulties experienced at this time. In 1880, he wrote to James Chance, recalling that in about 1828, when he was at Cambridge, he ‘had to wait for years for a 4-inch object of glass.’ What was lacking in Britain was collaboration between the optician, the scientist and the glass technologist.

In 1824, the Royal Society appointed a Committee of its Fellows and members of the Board of Longitude to look into rectifying this problem. Michael Faraday, Sir John Hershel and others formed a sub-committee to experiment with various mixtures of glass and techniques of heating and cooling the glass. The London glassmaker Pellatt and Green was commissioned to build a furnace for the project, but Faraday found this to be too inconvenient, so a small furnace was set up at the Royal Institution. From 1827 for the next three years, Faraday spent much of his time trying to produce good quality optical glass, writing a paper for the Royal Society ‘On the manufacture of glass for optical purposes’ in 1829. It proved to be a frustrating time for Faraday and in 1831 he wrote to the Royal Society requesting that he ‘lay the glass aside for a while, that I may enjoy the pleasure of working out my own thoughts on other subjects’. The failure of the Royal Society and Faraday’s experiments indicates how they underestimated the difficulty of producing optical glass. Though Faraday was undoubtedly a talented experimental scientist, the task was beyond even his capabilities.

Meanwhile, across the English Channel, George Bontemps was one of the French glassmakers attracted by the French Academy of Science’s offer of a prize for the best optical glass produced by a French glassmaker. Bontemps was put in touch with the eldest son of Pierre Louis Guinand, Henri, who wanted to sell his father’s secrets. Bontemps – one of the most skilful glass technicians in France – purchased them for 3,000 francs (£5,290 in today’s money) in 1827. After initial attempts at his glassworks in Choisy le Roi near Paris failed, Bontemps, after parting ways with Henri Guinand, decided to persevere alone. By 1828, he was ready to present to the French Academy some lens discs that had been made using better stirring methods to obtain a high-quality flint glass. Bontemps was later to come to Chance Brothers to direct their optical glass works and this enabled the firm to extend their operations to the making of optical quality glass for lighthouse lenses in 1849.

Early lighthouses and the catoptric illumination system

How did lighthouse illumination progress from the earliest times to the introduction of dioptric lenses in the 1820s? The story begins with early attempts to magnify the light from a small spot into a powerful beam that could be seen by mariners as they sailed over the horizon and saw land. The first beacons were open fires on windswept headlands, more smoke than flame, so practically useless at