If you stand close to the small vivaria lining the western outer wall of London Zoo’s Reptile House and look upwards you will see daylight. Natural light was admitted as part of the design not because of any wish to save electricity but for the good of the inhabitants. The glass in the roof of the house and the vivaria was not ordinary glass but Vita, a glass of special composition to allow the transmission of rays at the ultraviolet end of the spectrum.
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| Entrance to the Reptile House, 2011 Photograph by William Hook via Wikimedia |
Joan Procter’s inclusion of Vita glass was just one manifestation of the Zoo’s pioneering efforts, through Sir Peter Chalmers Mitchell FRS, to improve the health of zoo animals. In fact, he was riding the crest of a scientific and populist wave sweeping across the world in the inter-war years that can be summed up as: fresh air, sunshine and vitamins. The architect, John Stanislav Sadar has put the whole development of Vita glass in that context. In short, because ultraviolet rays were known to kill bacteria, and their importance in the synthesis of vitamin D was emerging, sunlight must be good for you. Put into the context of the industrial urban environment: poor housing; enormously high levels of air pollution, and the consequent human diseases of rickets, tuberculosis and chronic respiratory morbidity, it is hardly surprising that scientific, clinical, social and commercial efforts combined to promote the outdoor life, sunshine and patent medicines.
In the 1920s it was known that ordinary glass blocked the transmission of ultraviolet rays in sunlight. Ergo, glass that would transmit ultraviolet would be healthier. To solve this problem, Francis Edward Everard Lamplough (1881-1975) appeared on the scene.
Whether Lamplough thought of the idea himself or was urged to try by scientists or others in the sunshine movement is not clear. This is what he had to say in his lecture to the Royal Society of Arts in 1929:
The scientific research involved was carried out with much encouragement from Professor Leonard Hill, and also from the authorities of the London Zoological Gardens, Dr Saleeby [Caleb Williams Saleeby, 1878-1940] and others, and early in 1925 the first full scale melting was made of window glass (designated “Vita”) pervious to the health rays.
Professor (later Sir) Leonard Erskine Hill FRS (1866-1952) was the scientific leader of the fresh air and sunshine movement. He was Director of Applied Physiology at the National Institute of Medical Research. Hill’s main interest was in using lamps that emitted in the ultraviolet or infrared to mimic the effect of sunlight on the body for therapy and prevention of rickets, for example. The Times (22 May 1928) carried the story† of how Hill came to be involved:
Early in 1925 the Council of the Zoological Society of London had under consideration the construction of a new Monkey House. The existing house, built in 1864, provided no open-air cages and was arranged on the theory that artificial heat was the primary requirement for the health of these animals. Dr. Chalmers Mitchell, Secretary of the Society, had shown in 1911 by an elaborate study of the mortality statistics in the Zoo for a period of over 30 years, that health was better and the duration of life longer in monkeys (and most other warm-blooded creatures) kept with free access to the open air in all weathers and without artificial heat. Later observations showed that, although cold air was better than warm, stale air, good hygiene required also radiant heat and sunlight.
It was decided before going to the expense of constructing a large new Monkey House to erect a small-scale experimental house in which the theoretically best conditions might be tried out during at least one winter. Fresh air and heat were easy to provide, and Dr. Leonard Hill, F.R.S., who had been working out proper, conditions for sickly children at the National Institute of Medical Research, Mount Vernon, Hampstead, and who had studied the conditions in the houses in the Gardens, described to Dr. Chalmers Mitchell the part played by ultra-violet rays. He advised the provision of electric light in globes of fused quartz which was almost, completely transparent to the health-giving rays. He also, informed him of certain laboratory experiments with a new form of glass, called “Vita” glass, which had not then been made on a commercial scale, but which was transparent to the ultra-violet rays of sunlight which were cut off by ordinary window glass. Dr. Mitchell, on behalf of the Zoological Society, commissioned the inventor of “Vita” glass to make a sufficient quantity to glaze the experimental house.
The usual difficulties in the change from laboratory to manufacturing scale arose, but were surmounted, and the Zoo's experimental house was the first building to be provided with “Vita" glass. Spectroscopic examination showed the transparence of the new material to ultra-violet rays, and the effect on the animals was so good that the Lion House and the new Reptile House, and, later, the full-size new Monkey House, were all lighted with “Vita” glass with complete success in every case, as shown by the better health and better spirits of the animals.
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| Sir Leonard Erskine Hill (1866-1952) in 1934 Bassano Ltd. National Portrait Gallery |
I have been able to find surprisingly little about Lamplough. Educated at Oundle and Cambridge he was awarded a First in Natural Sciences in 1904. Elected a Fellow of Trinity College in 1906, he also served as Additional Demonstrator in Chemistry between 1914 and 1917. He married Augusta Gertrude Stewart in 1907. At the start of the Second World War, he was working at the Royal Aircraft Establishment, Farnborough. He died in 1975 at Woodchester, Stroud, Gloucestershire. During the work on Vita glass he is described as Late Fellow of Trinity College, Cambridge. My impression is that he was working for Chance Brothers, the famous makers of glass and lighthouses (he had patents for a gas valve used in lighthouses in 1920-21), throughout this period though perhaps not as an employee but as an independent inventor or consultant. He was also the inventor (The Times 22 May 1928) of the artificial daylight ‘Daylamp’ and a glare filter for Chance.
Lamplough’s development of a low iron content glass that transmits in the ultraviolet range depended on the findings of Sir William Crookes that oxidised ferric iron absorbs, whereas ferrous iron transmits, ultraviolet. The Chance works would have been highly familiar with Crookes’s work since they were responsible for developing and manufacturing special ultraviolet-blocking glass.
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| Spectrographs showing the transmission through Vita compared with ordinary window glass. From Lamplough's RSA paper |
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| The Times 22 May 1928 |
After the installation of Vita glass at the Zoo, the New Health Society (i.e. Hill et al.) and Saleeby’s Sunlight League promoted its use in hospitals, schools, farms and greenhouses. The Times (25 April 1933) reported that Vita glass had been installed at Clifton College in Bristol and (3rd October 1929) on a veranda roof at a hospital.
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| Advertisements in The Times in 1928 and 1932 |
When Marlborough House was being prepared for occupation by the then Prince of Wales The Times (8 November 1927) reported that his ‘business room’ was glazed with Vita. Perhaps that’s why he had the energy to pursue Mrs Simpson. Domestic houses were also targeted for sales. Indeed, those involved saw it capturing the entire market for window glass. But that optimism was not justified. Production ceased in the 1930s and stocks were gradually sold off. What went wrong?
The reasons for the rapid decline in sales of Vita glass are a mixture of doubts over efficacy, errors made in the commercial arrangements for manufacturing and marketing, price and competition. Although Lamplough dealt with the technical problems in his lecture in 1929, namely, the early, rapid but partial loss of transmission of ultraviolet when Vita glass was exposed to sunlight and the problems of dirt and grime settling on the glass, doubts remained, apparently, on its efficacy under natural conditions on buildings.
The manufacture and marketing arrangements, described by Sadar, must be an object lesson in how not to do it for business students. Chance Brothers sub-licensed* Vita plate-glass manufacture to Pilkingtons; marketing for both companies was done jointly by the ‘Vita’ Glass Marketing Board which not only caused problems for the marketing departments of the two companies but also inadvertently advanced the cause of rival and better products appearing on the world market. Tests in the U.S.A. showed that Corning’s Corex glass allowed much greater transmission of ultraviolet than Vita. I do not know if Lamplough, or the two British glass manufacturers, tried to improve his glass as better glasses appeared. Finally, there was the price which Sadar estimates as six times more expensive than ordinary window glass. In the relatively affluent 1920s installing Vita might have been seen as ‘the’ thing to have by the worried unwell (like the silly ‘health’ foods of the 2010s) or public bodies trying to improve the health of schoolchildren but by the economically depressed 1930s specifying or choosing an expensive window glass would have been a different matter. A few minutes’ exposure to natural sunlight was of course more effective in synthesising vitamin D than hours spent behind a Vita glass window.
All the promotion of the health-promoting properties of ultraviolet ignored the growing evidence of the dangers of excessive exposure of the skin and eyes, much of it provided by Hill!. But by the 1930s such actual or possible deleterious effects of the more extreme examples of therapy by sunlight were being recognised and the medical craze of the 1920s began to fade away, to be replaced by vitamin supplementation and the careful use of high-intensity sunray lamps. In most domestic and public spaces we can only be thankful that ordinary window glass is impermeable to the ultraviolet end of the spectrum unless, of course, we fancy a getting a suntan behind the privacy of our french windows.
Two questions remain on Joan Procter’s Reptile House. The first is whether or not sufficient ultraviolet rays reached the inhabitants for the synthesis of Vitamin D. Looking at the technological solutions now applied to vivaria to supply sufficient ultraviolet to many reptiles in captivity I doubt it. The second is whether any of the Vita glass on and in the Reptile House has survived (the less than successful Monkey House was fortunately demolished in 1970 as was the Lion House). If it has, then there is a solution to the first question since the natural ultraviolet irradiance in the vivaria can be measured. However, also installed in the Reptile House were some of Hill’s ultraviolet and infrared lamps. Vita glass was also used in a very different role to that in the windows—as a cover the quartz (ultraviolet emitting lamps) lamps to shield out the short wavelengths which had proved fatal to lizards.
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| Original layout of the Reptile House. Only at the two ends of the building have there been changes in inhabitants. The Times 15 June 1927 |
Successful in the Reptile House or not, the installation of Vita glass shows the determination of Chalmers Mitchell and Joan Procter to make London Zoo part of the movement to improve living conditions for all inhabitants of industrial Britain in the early decades of the 20th Century and to bring scientific advances to bear on problems of wild animal husbandry. As far as the Zoological Society is concerned the culmination of the fresh air and sunlight school was the opening of Whipsnade Zoo in Bedfordshire on 23 May 1931, four months before Joan Procter’s death.
*I have been unable to find any patent by Lamplough on Vita glass. Chance probably relied on protection by know-how rather than releasing the formula in a patent.
†Those aware of Chalmers Mitchell’s other jobs will realise that the reports ON him for The Times were probably written BY him as science correspondent for that newspaper.
Sadar JS. 2012. ‘Vita’ glass and the discourse of modern culture. In, Writing Design, edited by G Lees-Maffei, pp103-117. London: Berg.
Lamplough FE [he often omitted the second E). 1929. The properties and applications of “Vita” glass. Journal of the Royal Society of Arts 77, 799-811.
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