NO GUNNERY WITHOUT GLASS - OPTICAL GLASS SUPPLY AND PRODUCTION PROBLEMS IN BRITAIN AND THE USA, 1914 – 1918 By Stephen Sambrook The manufacture of satisfactory optical instruments is entirely dependent of the availability of suitable types of glass. Although the term 'optical glass' is familiar to everyone interested in binoculars and telescopes, it is not always remembered that optical glass is unlike other species of glass, and furthermore exists in a tremendous variety of types. The term 'glass' is no more specific than 'metal', and as metals exist to cover a multitude of applications, so do optical glasses. As steel is made in a wide range of alloys, so some types of optical glass are produced in a variety of compositions. Unlike the glasses used for, say, windows or bottles, glass intended for optical instruments is chemically complex and requires extreme care in manufacture to produce a material entirely free from chemical and physical imperfections which might degrade its efficiency. The large scale production of optical glasses is a specialised and difficult field which even now is confined to relatively small number of companies. Today, these makers are distributed globally, but until 1914 optical glass production was centred in Europe, with the vast majority of the more sophisticated types coming from only one German factory. The Great War of 1914 – 1918 effectively ended this Teutonic monopoly, although whether German glass hegemony was curtailed is much less certain. In the early 20th century, Germany was by no means the only nation with a developed and viable optical instruments industry. Optical apparatus for science, industry and warfare were also made in England, France and the USA on a commercial scale, both to original domestic and licensed foreign designs. Nor was optical glass only made in Germany, although it must be conceded that most of the world's output did come from the Schott optical works in Jena. Before the 1880s, however, optical glass manufacture had been centred in England and France, with Germany being a net importer, particularly from the English makers Chance Brothers, of Birmingham. The other substantial optical glass maker then was the French firm Parra Mantois et Cie. at Paris, and between them these two firms supplied most of the optical glass used by European makers. Up to the late 1880s, the optical industry's total demand was relatively small, and neither firm maintained a large capacity for optical glass production, nor carried out considered scientific research in the field. Existing glass types seemed sufficient for clients' needs, and contemporary manufacturing methods were more than adequate for prevailing requirements. The structured scientific glass research begun in Jena in the 1880s was to change fundamentally the nature of the optical glass industry, and massively to influence the future production of instruments. By 1914, both Britain and the USA had significant optical instrument industries. Each country manufactured, inter alia, theodolites and microscopes, astronomical and terrestrial telescopes, galilean and prismatic binoculars, as well as special instruments specially produced solely for use by the army and navy – 'optical munitions'. Neither nation had a large army, and although the Royal Navy was considerably larger than the contemporary US Navy, the total volume of demand for optical munitions in each country was relatively small. These optical munitions, although comparatively few in number, were critically important in the sort of warfare which rapidly emerged in Europe, as well as at sea. Despite having a domestic optical manufacturing base, each country was actually a net importer of finished optical instruments as well as optical glasses. The outbreak of war in Europe in August 1914 had immediate, though differing, effects in both countries. The advent of the new 'Jena glasses' in the late 1880s and 90s had helped stimulate the already growing demand for optical instruments, particularly in medicine and science. These new glasses permitted the development of new and more efficient types of optical systems, considerably enhancing the capabilities of existing apparatus as well as allowing new sorts of instrument to emerge. In Britain, there was no determined attempt to produce any of the new glasses until Chance Brothers began serious laboratory experiments in 1909. In France, however, Parra Mantois devoted some considerable effort to copying the new types of glass being made by Schott, and by 1914 had succeeded in producing many of the 'modern' glasses, although whether their ultimate consistency and quality were the equal of the German originals was the subject of some debate. It appears that in Britain particularly there was a decided preference for Jena-made glasses at this time, although independent observers were not wholly convinced of their actual superiority. The Schott glassworks of Jena did not publish the formulae of their new glasses (whose range was constantly being increased), nor did they disclose the methods of manufacture. These glasses had all been designed on strict scientific principles to have particular characteristics to enable the computation of improved optical systems, and no effort had been spared to arrive at viable methods of commercial production. Chance Brothers had never worked on such a basis, using instead empirical methods which were scarcely more than trial and error until eventually an acceptable result was achieved. Their first scientific manager was not engaged until 1897, and from then until 1909, sporadic efforts consumed substantial amounts of money but achieved little of real value. More progress, and some real successes, were made between then and the outbreak of war, but in August 1914, Chance's monthly output of optical glass was scarcely 1,000lbs, and although some 'Jena' type glasses had been developed, their catalogue listed only 15 types of optical glass, compared to Schott's which listed hundreds of varieties. Nevertheless, Chance Brothers were confident of their ability to manufacture all the glasses needed for the instruments then being purchased by the Admiralty for the Royal Navy. The Admiralty was well aware that the fighting efficiency of its warships was dependent on the optical instruments used for directing gunnery and torpedoes. In 1912 it had voiced concern that its British suppliers leaned heavily on imported glass, and had specified that British glass should be used wherever possible in instruments supplied for the Royal Navy. Some contractors had to point out that in certain cases this was not possible, as the required glasses were not produced in Britain. The Admiralty's worries were emphasised by a1912 report from the National Physical Laboratory which pointed out in no uncertain terms that any future disruption of optical glass imports would almost immediately paralyse British instrument manufacture. Despite this awareness, no steps were taken materially to improve self-sufficiency before the outbreak of war, when many of the predicted difficulties did indeed materialise. One immediate consequence of Britain's declaration of war on Germany was that supplies of optical glass from Jena were promptly terminated. Making good this shortfall even in peace-time would have been problematical, as some of the glasses were obtainable only from Schott and their incorporation was essential for uninterrupted production of several types of essential military optics. This problem was immediately exacerbated because the only possible substantial alternative supplier, Parra Mantois, found its own capacity overwhelmed by orders from other European instrument makers whose German supplies had also been interdicted. French makers in particular were being called upon to increase their output of optical munitions both to replace losses in action and to provide certain instruments – such as binoculars – on an increasing scale as Army reserves were mobilised. To make matters even worse in Britain, there was a progressively increasing demand for optical munitions from the War Office, which organised supplies for the Army. The peace-time force of some 250,000 began to expand, first to a million, and then towards two million as the realisation grew that the war was going to be of several years' duration. The scale of orders being placed in Britain by early 1915 was on a level never previously imagined by the optical industry, and its ability to cope was severely constrained by acute shortages of optical glass. Munitions shortages of all kinds led to the creation of the Ministry of Munitions in the early Spring of 1915. One section – eventually known as the Optical Munitions and Glass Department – was dedicated to the production of optical instruments and optical glass, and its initial efforts were concentrated on overcoming the critical glass shortage. The problems here were manifold., and incapable of solution simply by increasing orders. There was only one optical glass maker in the country, and that firm was principally engaged in making general commercial glasses of the sorts used in windows and bottles. It was by no means willing to undertake a massive expansion of its optical glass capacity. Chance Brothers, like many others in early 1915, was by not convinced that the war would be of long duration. Being uncertain of how soon peace would return, the company was reluctant to spend very large sums of money on an expansion programme which might prove ultimately of little commercial value. Chance had already suffered heavy financial losses in trying to bring new glasses into production, and had met sales resistance from optical makers who believed, rightly or wrongly, that Schott glass was superior. Whilst the prevailing war would mean British opticians perforce using as much of whatever they could get from Chance, there was the probability that an early peace would mean makers immediately reverting to normal commercial production on a vastly smaller scale, and also going back to the familiar German glass types incorporated in previously computed optical systems. Chance also claimed that they lacked the necessary scientific staff to allow them to commence production of any quantity of the sophisticated glasses urgently being demanded. The firm was far from enthusiastic about becoming ever more deeply involved in a field which was essentially a minor part of its previous glass making programme, and the War Office made little progress in getting Chance's to expand output between August 1914 and April 1915. The optical department of the new Ministry of Munitions ( OMGD ) was much more successful in realising substantial improvements in supplies. Recognising that many of Chance's concerns were legitimate, and also aware how essential it was to secure an adequate domestic supply of optical glass, the OMGD brokered a deal with Chance, effectively setting up a state/private-enterprise partnership which provided both money and scientific expertise for the necessary expansion, in exchange for Chance Brothers achieving specified levels of output and maintaining the necessary plant and personnel. The agreement further provided for changed post-war circumstances, and gave Chance an effective monopoly in the future production of glass for British service requirements, as well the right to use the government financed plant for regular commercial production. The deal provided mutual rights and responsibilities for both the company and the state, and immediately transformed Chance's attitudes. Even before the contract was signed, Chance began to expand its capacity and increase output. The problems of increasing glass output were manifold. Not only had suitable new plant to be constructed and commissioned, but also entirely new types of glass had to be introduced to replace those now unobtainable. The design of these was only possible through detailed analysis of existing samples, but even then there remained the obstacle of raw materials. Even where optical glass was being made in Britain, the raw materials for it were practically all imported, many from Germany itself. New sources of supply had to be located and drawn on, and in some cases these difficulties were so severe that synthetic methods of manufacture had to be developed. Potash for example, had almost all been drawn from Stassfurt, and frantic attempts to produce it synthetically had to be made. Imports from overseas were increasingly disrupted by the U-boat campaigns, and the whole question of raw materials for glass remained problematical. By July 1915, British 'demands' for optical munitions by July 1915 had reached a level requiring over 200,000lbs (about 91,000 kilos) of optical glass annually, or some 17,000lbs (7,700 kilos) monthly. The term 'demands' perhaps needs some explanation, as it represents what the War Office thought it might need, rather than orders actually placed; it is perhaps symptomatic of the War Office's contemporary lack of clarity in planning . The 1915 agreement with Chance was for a monthly output of 8,500lbs (ca. 3,900 kilos), but this was subsequently increased to require an eventual output of over 17,000lbs. As War Office demands continued to grow, the OMGD commissioned a second factory (Derby Crown Glass) and also sought supplies abroad. Throughout 1915, the British optical industry was heavily dependent on French glass makers. By far the largest of these was Parra Mantois et Cie., but there were also other producers, of which the firm of Graillot, was the largest. Parra Mantois was an old established firm of considerable capabilities, to which the British urgently turned for glass deliveries in 1914 and 1915. Relations between Parra Mantois and its British customers were not always easy during the first year of the war, partly because Monsieur Mantois himself was 'a very difficult man to handle' (according to General Bourgeois, OMGD's French liaison officer) and partly because the War Office was sometimes highly inept in its actions. One of the conditions on which the French agreed to the release of optical glass was that their own already existing orders for infantry rangefinders, from Barr & Stroud of Glasgow, should be allowed to proceed without interruption. French glass was then essential for the production of these instruments, which the War Office had declined to order in peace-time, selecting instead the Marindin pattern (manufactured by Adam Hilger) because of its lower price. The Marindin rangefinder proved to be lacking in durability and accuracy, as well as being much more expensive to make than had been estimated. When active service use showed the War Office's choice to be grossly deficient, very large orders were placed for the Barr & Stroud type, and priority of delivery (under the Defence of the Realm Act) demanded at the expense of obligations to the French. It is unclear if the War Office actually understood the implications of this action, but by late summer of 1915 the French were sufficiently displeased by the shortfall in rangefinder deliveries seriously to consider embargoing their entire supply of optical glass to Britain. The cessation of French glass supplies would have been catastrophic. An OMGD document of November 1915 shows all the principal British makers having outstanding orders with one or more French glass producers. Three British firms in particular were entirely dependent of French deliveries, and had their production stopped the whole output of key instruments would have ceased. Barr & Stroud had the monopoly of rangefinder production; R. & J. Beck were then the only makers of the dial (or panoramic) sight for the artillery; and Taylor, Taylor & Hobson were responsible for almost the entirety of prism manufacture intended for binoculars. As it was, the OMGD was able to restore rangefinder deliveries, and the embargo never materialised. Glass supplies were not only obtained from France. The most important pre-war producer had been Germany and, perhaps surprisingly, some supplies of optical glass from there continued to be shipped to Britain throughout the entire duration of the war. This remains something of a mystery, but there is evidence in official statistics to indicate that glass was imported from German ports of origin, albeit in decreasing quantities, from 1915 to 1918. The figures not only quantify the amounts landed, but also give some categorisation of types. In 1915 there had been negotiations through embassies in neutral Switzerland to secure deliveries from Germany of particular optical munitions for the British forces. In principle, both sides were willing to trade, Britain supplying rubber in exchange, and an Act of Parliament was passed in 1916 to regulate, rather than prohibit, trade with the Enemy. This proposed barter never came into effect, at least in the form proposed. It must still be a matter of conjecture as to exactly how the acquisition of German glass was organised, but it is apparent that some considerable amounts were imported. By 1918, Britain was largely, but not entirely, self sufficient in optical glass production. Chance's catalogue then included virtually everything that had been obtainable from Schott in 1913, plus a considerable number of new types produced in response to specific requirements, particularly in photographic reconnaissance lenses. At least seventy types of optical glass were in production when the war ended, with output over 20,000lbs ( ca. 9,000 kilos) per month. The demand for a multiplicity of new types resulted from a perceived need to produce high grade optics, making the glass optimal to the instrument, rather than designing an inferior instrument around readily available glasses. Quality control was not always perfect, and there continued to be sporadic shortages of regularly used types, leading to continued reliance on the French glass industry to fill gaps. Substantial French glass contracts were cancelled in late 1918 when the war ended. Despite these difficulties though, a first class and high volume optical glass industry had been created, where before the war there was really only small scale manufacture of a very limited range. The American experience was not quite the same. The USA was affected by the European war from August 1914 onwards, but did not become a combatant until April 1917,when the scale and nature of the effects changed substantially. The US approach to optical glass production has to be seen in two stages; from August 1914 to March 1917, and then from April 1917 to November 1918. It has been asserted that no optical glass was made outside Europe before the Great War, but this is not absolutely correct. Some optical glass was made in the USA by Bausch & Lomb from 1912 onwards, although this was carried out on a small scale and possibly did not extend much beyond small- batch or experimental production. That it should have been done by Bausch & Lomb is not entirely surprising, as that firm was not only the largest optical instrument maker in the USA, but also very closely connected with the Zeiss Stiftung, or Foundation, at Jena. The Zeiss 'umbrella' included the Schott glass works, and it may be that there was some sort of encouragement from Germany towards Bausch & Lomb for the production of glass. Apart from this small enterprise though, all optical glass used in America was imported before the outbreak of war in 1914. The US optical instruments industry in 1914 was quite substantial, and made a wide range of scientific, technical, medical and general optical apparatus. However, very little was made for military use. The nation's armed forces were very modest. The Army numbered some 200,000 officers and men and possessed little in the way of artillery. The Navy's complement of cruisers and battleships – the principal employers of optical instruments for gunnery fire control – was numerically small, and although adequately equipped by contemporary standards by no means constituted the basis for a thriving optical munitions industry. Rangefinders, telescopes, periscopes, gun sights and binoculars were all being made, but on a relatively small scale. From 1914 to early 1917, this small industry benefited to some extent by orders received from the various European warring powers. Before 1914, the chief foreign supplier of optical goods to the USA was Germany. For practical purposes the USA was entirely dependent on foreign suppliers for optical glass, and principally from Schott at Jena.. Contemporary accounts suggest that, as in Britain, the presence of reasonably priced high grade imported instruments tended to discourage attempts to produce the same domestically. There were no protective tariffs, and domestic wage rates were significantly higher than those in Europe. German makers in particular marketed their products enthusiastically either directly or through local agents, and the foreign equipment carried a certain 'cachet' lacking in the US-made competition. Even though a few firms did make first class apparatus, the scale was still small, and wholly insufficient to encourage the creation of an optical glass industry. Once the European conflict began, it became apparent that glass exports to the USA might be disrupted, and this provided some stimulus in the establishment of an indigenous industry. Bausch & Lomb had begun the small scale manufacture of glass in 1912, followed in 1914 by the Bureau of Standards at Pittsburgh, Pennsylvania. The following year – by which time European glass deliveries were being adversely affected by the European conflict – Keuffel & Esser of Hoboken, New Jersey also began making glass for its own requirements. This company not only made optical instruments for science and commerce, they were also the US agents for the British optical munitions maker Barr & Stroud of Glasgow, whose rangefinders were the most widespread amongst the Allies now fighting Germany and the other Central Powers. The same year, the Pittsburgh Plate Glass Company began to attempt the production of optical glass, followed in 1916 by the Spencer Lens company of Buffalo, New York. Between August 1914 and the Spring of 1917, these firms made small quantities of 'fair quality' optical glass to supplement the now reduced quantities being shipped from Europe. European supplies were by no means terminated in 1914. Indeed, one of the complaints voiced by the British in 1915 was that Parra Mantois in particular was executing US orders apparently in preference to British ones, and a British commission of enquiry reported that US optical makers were not experiencing problems obtaining supplies. Neither should it be assumed that German glass ceased to be shipped, despite the problems caused by the British blockade of the North Sea, which was intended to paralyse Germany's foreign trade. Germany maintained trading links with Scandinavian countries, and it was entirely possible for neutral ships to carry German cargoes across the Atlantic, with manifests showing the port of embarkation as Scandinavian. Without substantial glass imports the US optical industry would have been crippled, but substantial British orders placed for instruments such as binoculars suggest that, irrespective of the source, the American optical industry was able to maintain output up to April 1917. Records suggest that one maker - Crown Optical of Rochester, NY - was specifically selected for development as a British supplier, and provided with suitable glass diverted from Chance's output. The declaration of war by the USA created an urgent problem as regards optical glass. Interestingly, Ordnance Department Document number 2037 records that 'European sources of supply … were cut off abruptly' at this point, although this cannot refer to French or British producers. The inference must be that US instrument makers were still relying to some considerable extent on German glass. To add to problems caused by the diminution of supply was the almost immediate and substantial increase in demand for the US forces which were to be massively expanded for the country's participation in the war. The US was even worse off than Britain had been in 1914 in respect of its ability to provide military optics for a rapidly growing military establishment which was intended to exceed two million men. The American response to this problem was significantly different to the way the British had tackled their difficulties in 1914 and 1915. Whereas the latter had initially employed a largely piecemeal approach, relying on voluntary co-operation driven from within industry, the US Council of National Defense immediately organised a combined effort involving scientists from the Geophysical Laboratory at the Carnegie Institution in Washington, the optical glass producers, and the US Army Ordnance Department. The Carnegie's Geophysical Laboratory had been engaged in research into silicate solutions, which were not unlike optical glasses, and the Laboratory's scientists were recognised as the only people with the necessary expertise to organise the production of such glasses quickly and efficiently. The willingness of government to place them directly under US Army supervision and introduce them straight into the industrial workplace meant that the whole range of processes involved was immediately placed under strict control and organisation. It was rapidly decided that all the essential optical munitions needed for gunnery and observation could be produced using only six types of optical glass which were already standard catalogue lines in Europe before 1914. The need was to provide sufficient quantities of adequate instruments, even if the performance of those was less than could be achieved using more sophisticated glasses. Volume was deemed more important than sophistication, and because the optical properties of the six selected glasses were already well known, the problem became one of production rather than design. It was decided to produce ordinary and borosilicate crowns, light and dense barium crowns, and light and dense flints. Using these, virtually all the telescope systems which formed the basis of gunnery, or fire-control, instruments could be manufactured to an adequate level of optical quality. That almost no such apparatus was being volume produced in the USA was, if anything, something of an advantage in the particular circumstances of Spring 1917. When the British had looked towards glass self-sufficiency in 1915, their problems were made worse by the diversity of glass types already being employed by domestic optical munitions makers. Many of these glasses were foreign propriety types, whose replacement would have meant re-design of entire instrument systems, and it was essential that they be duplicated by an incompletely developed home industry. No such problems faced those setting out to organise US glass production. Instead, instrument makers would be told to design according to a limited, but adequate, glass catalogue. Although the characteristics of the six selected glass types were familiar, their precise formulae were secret to their makers and detailed chemical analysis was necessary to produce practical formulae for their manufacture. As had been the case earlier in Britain, this was accomplished without excessive difficulty, leading on to the need to procure the ingredients and properly organise the processes of production. Domestic supplies of raw materials were promptly located with the aid of the department of the U.S. Geological Survey, and obtained in both adequate quantity and quality. This obviated the need to develop synthetic substitutes which had happened in Britain, and the greater part of scientific energy was free to concentrate on mastering the problems of production. Efforts were centred on the Bausch & Lomb glass facility at Rochester, where small scale manufacture had been undertaken from 1912 onwards. This had been carried on very much as a craft skill, not unlike the practices at Chance Brothers in England, relying heavily on trial and error, both of which were incompatible with the rapid achievement of progress. The rapid success of the Geophysical Laboratory staff in producing correct formulae by scientific, rather than empirical, methods proved instrumental in overcoming any resistance to new practices at Bausch & Lomb, whose glass plant had effectively been taken over by the Ordnance Department at governmental instigation. It appears that production there rose from about 2,800lbs (1,270 kilos approximately) in April, to almost 20,000lbs (circa 9,000 kilos) in November, a most considerable achievement. Once the Bausch & Lomb plant was turning out what the Ordnance Department itself described as ' Large quantities of optical glass of good quality', the Geophysical laboratory staff moved on, similarly to take over the plants at the Spencer Lens Company, and the Pittsburgh Plate Glass Company. The former plant seems to have been quite small, never accounting for more than 10% of total production. However, from December 1917 until the end of the war, 'excellent optical glass' was produced there at around 4,500lbs (just over 2,000 kilos) per month. The Pittsburgh Plate Glass Co. proved more problematical to re-organise, and attempts to modify existing plant proved fruitless. Only when new furnaces were installed was it possible to make good glass, and output by November 1918 was averaging over 8,800lbs (ca. 4,000 kilos) a month. Keuffel & Esser's glass works was not similarly subject to the Ordnance Department's attentions. Carl Keuffel had commissioned a furnace and overcome the initial difficulties in establishing production so that even before the US entered the war, his firm was producing good quality glass, and entirely independent of outside supplies. According to the Ordnance Department, this was done 'without outside help', which is also what had happened in 1915 at Barr & Stroud's plant in Glasgow, Scotland. It can only be speculative to consider whether the firms' similar actions resulted from their previous association, or whether they were associated because they thought along similar lines. Whatever the case, both were prepared voluntarily to expend their own money at times when respective national efforts to secure glass-independence appeared conspicuously lacking. Between April 1917 and November 1918, the US optical glass industry produced over 665,000lbs (295,000 kilos) of optical glass, with monthly output in the last six months of the period averaging over 48,000lbs (almost 22,000 kilos). Bausch & Lomb's expanded glass facility had produced some 65% of this substantial output. The Ordnance Department considered that there was sufficient capacity within the industry, as it then stood, to bring monthly production up to over 100,000lbs (45,000 kilos) if the need arose. This was a tremendous achievement in little over twenty months, especially when it is remembered that in early April 1917, scarcely 3,000lbs of optical glass was being made monthly in the whole of the USA, and the techniques of mass production of optical glass were virtually unknown there. This accomplishment had its price. In social and political terms, it was achieved only because the state effectively took over the industry, interposing military control and directing precisely should be done. In this, the USA went further than Britain, where state intervention had a different nature, being directed principally at the control of labour and profits. In technical terms, the achievement came through compromise on variety and quality. In this, the American approach was very different to Britain's, where the Ministry of Munitions readily accepted the need both to duplicate existing types and to develop new glasses to meet specific requirements, maintaining high levels of quality throughout. The US Ordnance Department accepted that a substantial proportion of American optical glass output was only 'fair and satisfactory for war time purposes', recognising that it was 'not of the best quality, but … satisfactory for low power instruments'. Nevertheless, some of the production was considered by the Ordnance Department to be 'equal to the best European glass', suggesting that once quantity ceased to be the over-riding preoccupation matters of quality would be satisfactorily dealt with. The Great War has been called 'the war of science and invention'. Without purpose made optical instruments, accurate gunnery and the associated observation procedures would have been impossible. Both Britain and the USA succeeded in overcoming crucial deficiencies in optical glass production in order to achieve adequate levels of production of satisfactory instruments, using different routes to attain the same goals. Where neither nation had a real optical glass industry in 1914, by 1919 both had well organised production facilities of very considerable capacity. It was to be ironic that the post-war downturn in demand for optical glasses should almost immediately plunge these new high-technology industries into crisis, with both governments rapidly losing sight of the factors which had led to their creation and the potential they possessed. Select Bibliography J.F. Chance A History of the Firm of Chance Brothers & Co. (London, 1919). Privately published but available in British libraries. The Manufacture of Optical Glass and of Optical Systems: a War-time Problem. Ordnance Department Document No. 2037. (Washington, DC, 1921) The Official History of the Ministry of Munitions. Vol. XI, The Supply of Munitions, Part III, Optical Munitions and Glassware (unpublished, London, 1923). Available in the UK at the Public Record Office Library.