Lithodipyra:   The Stone of Mrs. Coade

Though the products of Mrs. Coade’s manufactory could be made to look like stone, they were, in fact, not stone at all. In addition to being made to look like granite or limestone, they could also be made to look like marble, bronze and even wood. That is one of the reasons why, though the manufactory was in operation for over seventy years, and literally tens of thousands of items were made there, only a small percentage of that output has ever been recognized or cataloged. But Coade stone was a popular material for both exterior and interior architectural embellishments right though the Regency.

The special secrets and unique properties of Mrs. Coade’s remarkable "stone" …

Stone was traditionally a high-status building material, but it was almost prohibitively expensive for any but the most wealthy, partly because it was so hard and labor-intensive to work, but also because, from the latter seventeenth century, it carried a significant tax. From the early decades of the eighteenth century, numerous attempts had been made in England to develop an artificial stone which would be durable, but easy to work, with which could be made any number of decorative architectural embellishments which would meet with the approval of architects. But all of those early attempts at artificial stone failed, most because they were quickly discovered to be highly vulnerable to frost and freezing conditions. Other formulas failed because the finished product was not aesthetically pleasing and did not look like real stone. Perhaps the problem was that all of these failed attempts were formulated by men. For, in 1769, a woman developed a formula for artificial stone which not only met all the criteria, but exceeded them.

Eleanor Coade moved to London from Devon with her parents in 1762. Her father’s business went into bankruptcy in 1769, and he died shortly thereafter. Eleanor, then thirty-six and unmarried, and the sole support of her mother and younger sister, set herself to save the family fortunes. She had spent some time working as a clay modeller, and seems to have been aware of at least some of the failed efforts at making artificial stone. By the end of the year she had developed a superior formula and opened a factory in Lambeth to manufacture her new product. She called her new factory Coade’s Lithodipyra Terra-Cotta or Artificial Stone Manufactory, and it was located at King’s Arms Stairs, adjacent to Narrow Wall. The term "lithodipyra" was constructed from the Greek words meaning stone twice fired. And in a sense, it was. Based on her experience working with clay, she was well aware that any ceramic piece would be subject to shrinkage when it was fired in a kiln. The greater the shrinkage, the more distortion was likely to occur in the finished product. Therefore, she included a large percentage of grog, which was previously fired stoneware that had been crushed and ground to a fine powder. She also added crushed glass and sand, which, along with the grog, were kneaded into a ball clay base to form the final body compound. This compound was then formed in a mold, worked by hand to achieve the very fine detail, then allowed to dry. Once the piece had dried, it would be fired in the kiln at very high temperature for several days. Most ceramics shrink between 10% to 20% when they are fired in the kiln, but with such a high percentage of previously fired material, Coade stone shrank no more than 8% when it was fired, even at these high temperatures.

The small percentage of shrinkage in Coade stone meant that it could be used for the modelling of even very large pieces, with barely any distortion during firing. But Coade stone also had other superior qualities. Because of the high percentage of grog and the use of sand in the artificial stone compound, the finished product was identical in appearance to stone. The other formulas had looked more like glazed stoneware and tended to be a more earthen color than real stone, while Coade stone was a grey or buff color. In fact, it was nearly indistinguishable from fine-grained limestone. However, the most significant property of Coade stone was that it was completely impervious to frost or freezing. In fact, it was even more durable than real stone and the harshest weather had no effect on anything made of it. Another highly desirable quality was that it was malleable enough to be used in the making of objects with very fine detail, and that detail was retained during firing because of the very low shrinkage rate.

But despite the fact that Coade stone was a superior product, Mrs. Coade initially had some difficulty in marketing her artificial stone. Though she never married, Eleanor Coade was known by the courtesy title of "Mrs." Coade from the time she opened her factory. That was the practice during the Georgian era when referring to a woman in business, regardless of her marital state. The poor performance of the previous artificial stone formulas had made architects and builders rather leery of using any artificial stone material. There were also a number of stone-masons, concerned for their livelihoods, who maintained that nature had to be better than art, that the real thing would always be preferable to any imitation. However, there were a small but growing number of architects who approved of the application of art and/or science to industry, and believed that man, or woman, could improve on the products of nature. And, within a very short time, Mrs. Coade’s stone itself helped to increase sales, as it was proven to be extremely durable, regardless of the type of weather to which it was exposed.

Serendipitously, Mrs. Coade happened to introduce her new artificial stone at just the right time, for the heavier Baroque style of architecture had already given way to the lighter, more delicate Rococo style and the early Neo-Classical style was just coming into fashion. The malleability and durability of Coade stone meant that it could be used to create elegant architectural embellishments which were quite delicate and ornate in appearance, yet exceptionally sturdy and durable. It was also in the latter decades of the eighteenth century that England saw a building boom, as men of means and taste either restored and renovated the old family pile, or built entirely new and fashionable stately homes and town houses to proclaim their wealth and status. Within a decade, even those of more moderate means were also renovating or building new homes in the more fashionable styles in order to imitate the upper classes and declare their own good taste and social standing. Coade stone was perfectly situated to meet this need. Though it was not cheap, it was still much less expensive than real stone, and Mrs. Coade always took great care to call it "artificial stone," thus ensuring it was not subject to the taxes which were levied on real stone. Within a very short time after Coade stone was introduced, Mrs. Coade was able to make her special stone objects using molds, thus also reducing the cost of those items which could be easily reproduced without the labor-intensive handwork needed to model a single unique piece.

Perhaps Mrs. Coade’s most important contact, and certainly her best customer, in those early years was the architect, Robert Adam. His fashionable style of Neo-classical architecture was quite delicate and graceful, and Coade stone could be worked to precisely and reliably replicate his light and elegant designs. There are tantalizing hints that Mrs. Coade had a tendré for Robert Adam, though no conclusive proof has ever been discovered. Regardless of their relationship, he placed a great many orders with Mrs. Coade for a wide array of artificial stone objects for his clients, right up until his death in 1792. Other leading architects soon took notice of Adam’s supplier of architectural embellishments and also began to place orders with Mrs. Coade. It was not long before Mrs. Coade’s manufactory supplied items for a number of fashionable architects, including Sir William Chambers, James Wyatt, John Nash, Henry Holland, Sir John Soane, and in the later years of the factory, to Sir Charles Barry, among others. Coade stone items were used at Carlton House, the Royal Opera House, the Bank of England, Chiswick House, the Royal Hospital at Chelsea, St. George’s Chapel at Windsor, Ham House at Richmond, Alnwick Castle in Northumberland, and Culzean Castle in Scotland, not to mention the many pieces which were supplied to George IV for the renovation and expansion of the Queen’s House when he made it over into Buckingham Palace. Mrs. Coade’s manufactory even supplied Coade stone items to the American architect, Charles Bullfinch, and to Charles Cameron, who was redecorating the Palace of Tsarkoe Selo in St. Petersburg, Russia, for the Empress Catherine.

Initially, the output of Mrs. Coade’s manufactory was primarily applied decorative exterior architectural elements, such as over-door keystones, door and window surrounds as well as decorative string courses and quoins. But soon after opening her factory, Mrs. Coade employed the talented sculptor John Bacon, who created a number of sculptural architectural elements, one of the most popular of which was a reproduction of one of the female caryatids from the south porch of the Erecthion on the acropolis of Athens. Bacon produced a mold from which these caryatids could be made in volume and thus at a reasonable price. At about the same time, Bacon began sculpting various free-standing classical figures in various styles and sizes, for which he also produced molds and these pieces also quickly became very popular. These free-standing classical figures were used as roof-top ornaments on grand classical buildings, but they also be came very popular as garden ornaments. These garden ornament offerings soon expanded beyond classical figures to various animals, both mythical and real, as well as other fashionable motifs such as beehives, pineapples and grand Italian vases. Because they were hollow, these Coade stone products were soon much in demand for fountain ornaments, since the piping needed for the fountain could be easily hidden inside them, unlike real stone sculptures, which were solid.

Once Coade stone ornaments became popular, it was not long before Mrs. Coade’s manufactory was also turning out interior architectural elements as well. Since Coade stone could be made to look like stone, or even marble, it was an excellent material for the making of faux marble mantle-pieces. Curiously, Coade stone was also used to produce mantle-pieces which looked like carved wood, but these faux wood Coade stone mantle-pieces had the advantage that they were completely fireproof. Many styles of mantle-pieces could be found in Mrs. Coade’s catalog by the end of the eighteenth century, most at fairly reasonable prices. Other interior decor pieces were made, in particular candelabra, in both table-top and floor-standing models. It is known that a number of these, of both types, were made for Carlton House. Another section which could be found in the Coade catalog by the beginning of the nineteenth century was for interior sculptures. These could be made to look like polished marble and were large enough to require their own niche in a grand room. Others were small enough to fit on a table-top or even a bracket shelf. Since Coade stone was fired at a very high temperature, it could take additional heat without cracking or other damage, and by the early nineteenth century, many people had their smaller Coade stone sculptures bronzed. A bronzed Coade stone sculpture would be much less expensive than a sculpture made completely of bronze, though it would be nearly impossible for anyone to tell the difference. There are probably a great many small Coade stone sculptures which have been bronzed that are still extant, but since it is nearly impossible to distinguish them from a sculpture made completely of bronze, they have never been properly identified. A number of monuments to various military and political figures were also made of Coade stone, many of which were then painted to create a more life-like representation of the person they commemorated. Some of these monuments have been assumed to be made of wood, and there are probably some which are also yet to be identified as Coade stone.

By the time the Prince of Wales had become Regent, the Coade stone manufactory had been operating for more than forty years and there would have been many thousand Coade stone objects in place all over the British Isles. In addition to many decorative pieces for both interior and exterior architecture, Coade stone had been used for more utilitarian objects such as chimney pots, friezes and column capitals. By then Coade stone was also used to make ornamental garden seats and benches, not to mention tomb ornaments, and in some cases, complete tombs. For example, both Capability Brown and Admiral Bligh, of HMS Bounty fame, were buried in Coade stone tombs. And, by the Regency, all of these objects had truly demonstrated their durability beyond any shadow of a doubt. A few of the houses and other buildings which had Coade stone elements had burned. Though the Coade stone elements were covered with soot, when it was cleaned away, the Coade stone pieces were none the worse for wear, intact and without cracks. No matter how harsh the weather to which they might be exposed, Coade stone objects retained their sharp lines and crisp edges, regardless of their age. Though not completely impervious to moss and lichens, Coade stone garden ornaments were very resistant to their growth, and these plants took noticeably longer to take hold on the surface of Coade stone ornaments than they did on real stone.

So, Dear Regency Authors, how might a Coade stone object figure in one of your stories? Perhaps it is known that someone had hidden something in the garden of a stately home years before the story opens. While tying to seek it out, the hero or heroine notices that most of the stone garden ornaments are heavily weathered and covered with moss or lichens. But one garden ornament has practically no lichen growth and its lines and edges are sharp and crisp, having suffered very little effect from years of weather. On closer inspection, they realize it is a Coade stone ornament, and therefore, must be hollow. When it is upended, and a search made of the interior through the opening in the bottom, the item which had been hidden is found inside. Or, the villain suspects that some piece of evidence which could prove him guilty of a heinous crime is hidden in the study of his partner in crime, or his implacable enemy, who has since passed away. Though he has searched high and low, he cannot find it and ultimately decides to set fire to the room. Though the residents are alerted in time to save the rest of the house, that room is completely destroyed. Or is it? Did the now departed occupant of that room have a bronze sculpture which was always kept there? Is it found in the rubble after the fire, with the bronze melted and distorted, beneath which is seen glimpses of a stone body? Impervious to heat, though the bronze on a Coade stone body might melt away, the sculpture beneath would survive unscathed. Like all Coade stone sculptures, it is hollow. What might be found inside?

Next week, the tale of Mrs. Coade, a woman as remarkable as the artificial stone she created, and the extensive manufactory from which she sold her wares.

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About Kathryn Kane

Historian with a particular interest the English Regency era.   An avid reader of novels set in that time, holding strong opinions on the historical accuracy to be found in said novels.
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11 Responses to Lithodipyra:   The Stone of Mrs. Coade

  1. Yay, worth waiting for – thank you!

    • Kathryn Kane says:

      You are most welcome!

      I am sorry you had to wait so long. I know you asked about Coade stone this past spring, but it took much longer than I had anticipated to get some of the reference materials I needed through Inter-Library Loan. But I think they were worth waiting for, since wading through all that material gave me a much better understanding of Coade stone and of the woman who invented it.

      To answer the question you posed in response to one of my cottage orné articles, now that I understand how Coade stone was made, there is no chance it could have been used to cover the walls of any cottages orné in order to create that textured surface. It was a ceramic compound which had to be fired in a kiln to become useable. However, Coade stone could easily, and probably was, used to create fanciful garden ornaments and furniture in a rustic style to furnish the gardens of such cottages.

      I think you will also like next week’s article, which will be about Mrs. Coade and her factory, which, apparently, even during the Regency, was rather posh.

      Regards,

      Kat

      PS – I hope I have not unleashed too many plot bunnies! 😉

  2. Simon Scott says:

    Thanks for your article. I always love reading about the amazing Mrs Coade. But she wasn’t the first to create an artificial stone. That honour goes to Richard Holt who took out 2 patents in 1722. I agree that Alison Kelly’s book on Coade is the best. But I would also recommend Claude Hitching’s new book on Pulham as well as my own on Artificial Stone as it puts Coade into context – deals with her predecessors and followers right up to the twenty first century. Have a look at http://www.haddonstone.com/Haddonstone.aspx?ID=92 for more information.

    • Kathryn Kane says:

      I was aware of Richard Holt’s efforts, but they pre-date the Regency by nearly a century, so were not really appropriate to address here. In addition, my understanding was that his version of artificial stone used ball clay that was of a brownish color so his product looked less like stone and had the added disadvantage that it did not stand up well to frost and freezing temperatures.

      Both your book and Mr. Hitching’s came to my attention while I was researching artificial stone, but the Pulham’s were not really active until the reign of Queen Victoria, thus beyond the scope of The Regency Redingote, as is yours, which seems to be primarily devoted to more modern uses of artificial and “cast” stone.

      Thank you for stopping by and taking the time to share your insights, for those who may wish to pursue information on artificial stone beyond the Regency era.

      Regards,

      Kat

      • Simon Scott says:

        Thanks for your reply. You are quite right that the likes of Holt and other artificial stone manufacturers predated the Regency period. I just wanted your readers to be aware that the Regency was not the first period during which such embellishments had been created for use in landscapes and buildings. And, it must be remembered that Coade did not have a monopoly – she had many competitors in operation during her own time.
        I would, however, disagree that my own book is primarily devoted to modern uses of artificial stone. Indeed, only 23 pages relate solely to the twentieth century. Its aim was to provide an overview of all significant manufacturers from Holt to the present (including Coade) and to look at changing perceptions to the use of artificial stone (as well as manufacturing techniques) through those 290 years. As a footnote, the first James Pulham was active from the early 1830s, arguably at the end of the Regency period.

  3. Kathryn Kane says:

    I stand corrected with regards to your book! So far, I have only seen an excerpt of it, through an electronic resource via my local library. The portion I saw related to modern-day uses of artificial stone and I assumed that was the full scope of your work. My apologies!

    The so-called “long Regency” does extend right through the reign of William IV, who died in 1837. However, I seldom post articles here that go that far past 1821, the year in which the Prince Regent was finally crowned King George IV. And, to be perfectly honest, I was as much fascinated by Mrs. Coade herself as I was by her artificial stone, which is why I limited myself to Coade stone for this article. That remarkable lady will be the focus of the article I am planning to post next week.

    I am sure the additional information you have provided will be of interest to those who would like to pursue the broader history of artificial stone, outside the limits of the Regency. Thank you for sharing your knowledge.

    Regards,

    Kat

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