I am a big fan of Matthew Boulton and the Soho Mint. I might even go as far as to say that he and, to a slightly lesser extent James Watt are my numismatic heroes. I am enamored with the scientific ingenuity, ambition, and artistic ability so boldly on display by the products of the Soho mint. In my opinion, Boulton’s application of steam-powered presses paved the path for an era of artistic expansion and increased quality of the numerous tokens, medals, and coins he produced. Take, for instance, his regal English copper. These high-quality coins were mass produced with a standard weight, diameter, and thickness. Boulton’s copper coinage was far superior in terms of both strike and design than the contemporary copper products of the Royal Mint. At the time, the Royal Mint rarely produced copper coinage, which in part was due to the slow production rate using hand-operated presses. When they did manage to produce copper coinage, they were of considerably lesser quality, often poorly struck, and widely counterfeited in comparison to the products of the Soho Mint. This is not to say that English copper produced by the Soho Mint was immune to the evils of counterfeiting. Still, the increased quality certainly made it more challenging to engage in such activity. Despite this, Boulton eventually provided something absent in England for centuries – a sufficient supply of high-quality regal copper coinage (Brooke, 1932).
The story of how Boulton found his way into the minting business is rather interesting, but that is a different story for another day. Instead, the point of this post is to walk you through the mystery surrounding the little metal shells that, at times, can be found alongside a coin, token, or medal produced at the Soho Mint. The title probably had some of you wondering what I meant by “silver-lined brass shells”. This term refers to a case made of two “shells” that fit firmly around the edge of the piece, rather it is a coin, token, or medal, and provided some protection. These little shells were made of brass, but the inner portion was silver lined hence the term “silver-lined brass shells”. Pieces that have retained their original shells are incredibly scarce, so much so that the vast majority of the collectors have never seen them beyond an auction catalog or on a website. The purpose and origin of the shells was a mystery to me for years, but not for lack of trying to locate information. There is just little to no reliable information openly available, at least none that I have found so far.
I found the lack of available information to be both frustrating and intriguing. The more I thought about it, the more questions that came to mind. Who created the shells? Why did they create them? Were they only used in particular circumstances? None of the numerous books I read about either Matthew Boulton or the Soho Mint provided any more detail. At best, they might include a picture of a beautiful coin with the caption “1806 Irish ½ Penny with original silver-lined brass shells” and nothing more. I was starved for more information but was at a loss as to where to find it. Given what I gathered over the years, I started to make a few assumptions to help address some of the questions I had.
My first assumption was that Matthew Boulton came up with the idea for the shells. It is no secret that Matthew Boulton was a perfectionist and that his unwillingness to settle for anything less than perfect nearly cost him everything several times during the early days of his career (Doty, 1998; Selgin, 2011; Gale & Hist, 1966). Although I have not had the pleasure of personally inspecting the Soho papers, I have read excerpts provided by either Doty (1998) or, to a lesser degree Dickinson (1936), and they speak volumes to just how meticulous Boulton was. Even Fist and Hist (1966), who cover the Soho Manufactory more broadly, point to the same conclusion: Matthew Boulton was dedicated to providing only the best quality pieces regardless of what the item was. Could it be that simple? Did Matthew Boulton come up with the idea for the silver-lined brass shells? There seemed to be enough circumstantial evidence to suggest so, but I recently learned that this assumption might be incorrect.
I recently become acquainted with a very knowledgeable gentleman named William McKivor (A.K.A. Bill), who made me think critically about the first assumption I made. His experience is unique in that he purchased a bulk of the James Watt Jr. Collection and almost the entire Boutlon Family collection. This is significant because the majority of the pieces that have retained their shells were directly part of either the Boulton or Watt collections. Excluding the Boulton and Watt families, there is likely no one more familiar with the shells than Bill. He pointed out to me that most of the pieces he had handled with the shells were what Peck (1964) classified as “late Soho”. For those of you unfamiliar with this term, let me explain. Peck uses three classifications to broadly group the numerous English copper coins associated with the Soho Mint (i.e., early Soho, late Soho, and restrike). Early Soho is used to denote coins struck close to the date indicated on the coin; late Soho refers to coins struck at Soho at later date than indicated on the coin; restrike denotes coins struck in the mid-19th century by Taylor using salvaged Soho dies.
The fact that the coins typically contained in the shells are “late Soho” pieces provides important information, perhaps the shells too are a later Soho product. Boulton passed away on August 17th, 1809, at 81 years old. Peck makes no mention of when these “late Soho” pieces were struck, so it could have been well after Boulton’s death. Boulton’s son, Matthew Robinson Boulton (hereunto referred to as Matt), had been running the day to day operations of the Soho Mint for some time leading up to 1809. Perhaps maybe it was Matt and not Boulton who came up with the idea for the shells. This is a point that Bill made during one of our conversations. He also made another interesting point about James Watt Jr. and how he had become a partner with Matt shortly after Boulton’s passing. Watt Jr. would later become the Soho Mint master in 1815 and would secure a significant number of contracts for the Mint during his partnership with Matt (Doty, 1998). Watt Jr. may have come up with the idea for the shells, or as Bill suggested, it could have been Matt’s idea that Watt Jr. ran with. The story does not end here though. Bill also pointed out that neither of the Boulton’s were coin collectors, but Watt Jr. was. Watt Jr. likely understood the importance of preserving the specimens in his collection, and it seems likely that he would apply this same level of care to the pieces he produced at Soho. Perhaps Bill is correct, maybe Matt had the idea, and Watt Jr. implemented it. We may never truly know, but for now, it seems that my initial assumption about Boulton’s involvement is less likely. Boulton may not have had anything to with the silver-lined brass shells at all.
With a firmer grasp on the “who” question, we can now focus on the “why” question. I already hinted at it, but my second assumption was that the shells were mostly used to house and protect the specimens within the Watt Jr. and Boulton family collections. It makes sense that two families tied to the Soho Mint would want to save a few pieces for themselves. As Bill suggested, Watt Jr. likely took advantage of the fact that the Soho Mint was a private business and struck a few coins he needed for his collection. This would certainly help make sense of all the “late Soho” strikes that Peck (1964) details in his book. Perhaps maybe he then made the shells to keep the coins “as struck” for his collection. Like my first assumption, there is some evidence to support this conclusion. For starters, almost all of the coins that have come up for sale with the shells are traced back to either the Watt Jr. or Boulton family collections. This is also a point that Bill was able to reassure me on given his unique tie to both family collections. Bill’s reassurance would have been enough, but even the few publications with photographs of coins with their shells have provenance back to either of the original collections (Clay & Tungate, 2009; Tungate, 2011). I should, however, note that several coins exist with their shells that are not tied to either the James Watt Jr. or Boulton family collections. I have two such pieces in my collection (pictured above), suggesting that Matt or James Watt Jr. may have sold/gifted a small number of coins in their shells at some point. It could also be the case that the original owner purchased these two examples from the family in the mid-1930s, and the documentation was lost somewhere along the way. I cannot say with any degree of certainty, but for now, it seems as though the pieces I have in my collection likely did not originate from either the Watt Jr. or Boulton family collections.
For the sake of clarity, Bill also mentioned that several coins from the Boulton collection did not have shells when he purchased them from the family. A potential example of this is a coin in my collection with a provenance to the Boulton family but without shells. Of course, it could also be the case that the shells were separated from the coin when it was sent in for grading and subsequently have been lost. This is also a mystery that may never be solved.
My second assumption seems to be partially correct as nearly all of the coins with their shells are tied back to the two families; however, this assumption is not correct whatsoever when considering the medals struck at Soho. I am not a medal collector, at least not in the way typically encountered within numismatic circles, so this point was lost to me until Bill pointed it out. Bill, however, is a seasoned medal collector, so this was a pattern that he discovered while handling the Boulton family collection. He suggested that perhaps the shells were a way of remarketing otherwise stale inventory. Now it may seem surprising, but not all of the medals produced at Soho were quick to sell. There is evidence to suggest that Boulton was not a massive fan of making medals. Küchler worked at the Soho Mint until death in 1810 and was primarily charged with die-cutting and designing, but he also was the leading artist for the Soho medals (Pollard, 1970). There is some interesting correspondence between Küchler and Boulton, which suggests that Küchler was much more interested in engraving dies for medals than anything else, but Boulton did not realize the same profit on medals as he did with his coinage contracts. Put simply, the medals were difficult to sell and took time away from Kuchler’s efforts from other projects. As noted by Pollard (1970), this is very apparent in the way Küchler was compensated for his work on the medals. He was paid a flat fee for engraving the dies; however, additional money was gained by sharing the profit of any medals that were sold. As Boulton expected, the medals were difficult to sell, and it appears a small quantity of each type remained in stock at Soho well into Matt and James Watt Jr.’s Tenure at the helm. Pictured below is an example in my collection of such a medal that has retained its original shells but has no direct link to either the James Watt Jr. or Boulton family collections.
So what might account for the handful of coins and medals with shells and no provenance to either the Boulton family or Watt Jr. collection? My third assumption attempted to account for the coins, but before my conversation with Bill, I was unaware that medals also existed with shells and no provenance. I had assumed that the coins might have been a form of advertisement for the Soho Mint and that perhaps the shells were included to further impress potential clients interested in a coining contract. After all, the shells would have done an excellent job keeping the delicate proofs “as struck”. This still may be true, but the point that Bill made about the medals might suggest another reason for the shells. He suggested that the shells may have been a way of remarketing otherwise stale inventory and thus making them easier to sell. This point seems logical, and there is some evidence to support it. In doing a little research, I found that the medals are encountered more frequently with shells and typically lack provenance to either collection. All of this suggests that maybe the shells were a way for Watt Jr. and Matt to reinvigorate interest in the leftover inventory.
Perhaps, in this case, the straight forward answer is the most likely to be true. Given the information I presented, it seems plausible that Matt and/or Watt Jr. are the ones we have to thank for the shells. In my opinion, it also seems plausible the shells were made for several reasons, to protect their collections, to secure future contracts, and to remarket otherwise stale inventory. On any note, I am thankful that Watt Jr. was a coin collector and took such pride in his collection. From what I have gathered, a good deal of his Soho coins came in shells. I find it awe inspiring that at one point each coin was encased within custom made shells and placed in a small piece of parchment with a description of the contents in his handwriting. The 1804 India Pice pictured below is a piece from my collection that has retained its shells and hand-inscribed parchment initially from the James Watt Jr. Collection.
This leads me to my most recent purchase, a 1799 proof farthing. This particular example has retained the original silver-lined brass shells and is remarkably well struck with very strong cameo contrast. As you may have already guessed, it is classified as a “late Soho” piece by Peck (1964), which hints at the possibility that James Watt Jr. had this piece struck to fill an empty hole in his collection and subsequently passed an example along to Matt. Or perhaps maybe, a small batch of these coins were struck as specimen examples to gain another coining contract for Soho. We may never truly know why this coin came about, but I take great pride in knowing that I can play some small part in preserving a piece of Soho history that has been passed down through the generations of the Boulton family.
Some of you may be wondering why the shells matter so much, and I suppose that is a fair question. The answer, I think, really depends on why you collect coins. I find myself captivated by the history of the pieces and how they relate to contemporary society. As Doty (1998) so eloquently explains, the Soho Mint marked a turning point in the industrialization of money that can still be felt over two centuries later. The silver-lined brass shells, as insignificant as they may be in the larger picture, were likely, in some part, used to preserve that legacy for future generations. I find it essential to preserve the coins, medals, and tokens of the Soho Mint alongside their “original packaging” as @Conder101 so thoughtfully put in one of my earlier posts about the same topic. To me, the little shells are a unique piece of Soho history that is all too often lost in the bigger picture.
Please feel free to share any Soho pieces in your collection that have retained their original shells!
References
Brooke, G. C. (1932). English Coins from the Seventh Century to the Present Day. London: Methien & Co. LTD.
Clay, R., & Tungate, S. (2009). Matthew Boulton and the Art of Making Money. Warwickshire: The Barber Institute of Fine Arts.
Dickerson, H. W. (1936). Matthew Boulton. Cambridge: Babcock and Wilcox, LTD. At the University Press.
Doty, R. (1998). The Soho Mint and the Industrialisation of Money. London: National Museum of American History Smithsonian Institution.
Gale, W. K. V., Hist, F. R. S. (1966). Boulton, Watt and the Soho Undertakings. Birmingham: Museum of Science and Industry.
Peck, C. W. (1964). English Copper, Tin, and Bronze Coins in the British Museum 1558-1958. London: The trustees of the British Museum.
Pollard, J. (1970). Matthew Boulton and Conrad Heinrich Küchler. The Numismatic Chronicle (1966-), 10, 259-318.
Selgin, G. (2011). Good Money Birmingham Button Makers, The Royal Mint, and the Beginnings of Modern Coinage, 1775-1821. Oakland, California: The Independent Institute.
Tungate, S. (2011) Matthew Boulton and The Soho Mint: copper to customer (Doctoral Dissertation). Retrieved from ProQuest Dissertations & Theses A&I.
I am a big fan of Matthew Boulton and the Soho Mint. I might even go as far as to say that he and, to a slightly lesser extent James Watt are my numismatic heroes. I am enamored with the scientific ingenuity, ambition, and artistic ability so boldly on display by the products of the Soho mint. In my opinion, Boulton’s application of steam-powered presses paved the path for an era of artistic expansion and increased quality of the numerous tokens, medals, and coins he produced. Take, for instance, his regal English copper. These high-quality coins were mass produced with a standard weight, diameter, and thickness. Boulton’s copper coinage was far superior in terms of both strike and design than the contemporary copper products of the Royal Mint. At the time, the Royal Mint rarely produced copper coinage, which in part was due to the slow production rate using hand-operated presses. When they did manage to produce copper coinage, they were of considerably lesser quality, often poorly struck, and widely counterfeited in comparison to the products of the Soho Mint. This is not to say that English copper produced by the Soho Mint was immune to the evils of counterfeiting. Still, the increased quality certainly made it more challenging to engage in such activity. Despite this, Boulton eventually provided something absent in England for centuries – a sufficient supply of high-quality regal copper coinage (Brooke, 1932). The story of how Boulton found his way into the minting business is rather interesting, but that is a different story for another day. Instead, the point of this post is to walk you through the mystery surrounding the little metal shells that, at times, can be found alongside a coin, token, or medal produced at the Soho Mint. The title probably had some of you wondering what I meant by “silver-lined brass shells”. This term refers to a case made of two “shells” that fit firmly around the edge of the piece, rather it is a coin, token, or medal, and provided some protection. These little shells were made of brass, but the inner portion was silver lined hence the term “silver-lined brass shells”. Pieces that have retained their original shells are incredibly scarce, so much so that the vast majority of the collectors have never seen them beyond an auction catalog or on a website. The purpose and origin of the shells was a mystery to me for years, but not for lack of trying to locate information. There is just little to no reliable information openly available, at least none that I have found so far. I found the lack of available information to be both frustrating and intriguing. The more I thought about it, the more questions that came to mind. Who created the shells? Why did they create them? Were they only used in particular circumstances? None of the numerous books I read about either Matthew Boulton or the Soho Mint provided any more detail. At best, they might include a picture of a beautiful coin with the caption “1806 Irish ½ Penny with original silver-lined brass shells” and nothing more. I was starved for more information but was at a loss as to where to find it. Given what I gathered over the years, I started to make a few assumptions to help address some of the questions I had. My first assumption was that Matthew Boulton came up with the idea for the shells. It is no secret that Matthew Boulton was a perfectionist and that his unwillingness to settle for anything less than perfect nearly cost him everything several times during the early days of his career (Doty, 1998; Selgin, 2011; Gale & Hist, 1966). Although I have not had the pleasure of personally inspecting the Soho papers, I have read excerpts provided by either Doty (1998) or, to a lesser degree Dickinson (1936), and they speak volumes to just how meticulous Boulton was. Even Fist and Hist (1966), who cover the Soho Manufactory more broadly, point to the same conclusion: Matthew Boulton was dedicated to providing only the best quality pieces regardless of what the item was. Could it be that simple? Did Matthew Boulton come up with the idea for the silver-lined brass shells? There seemed to be enough circumstantial evidence to suggest so, but I recently learned that this assumption might be incorrect. I recently become acquainted with a very knowledgeable gentleman named William McKivor (A.K.A. Bill), who made me think critically about the first assumption I made. His experience is unique in that he purchased a bulk of the James Watt Jr. Collection and almost the entire Boutlon Family collection. This is significant because the majority of the pieces that have retained their shells were directly part of either the Boulton or Watt collections. Excluding the Boulton and Watt families, there is likely no one more familiar with the shells than Bill. He pointed out to me that most of the pieces he had handled with the shells were what Peck (1964) classified as “late Soho”. For those of you unfamiliar with this term, let me explain. Peck uses three classifications to broadly group the numerous English copper coins associated with the Soho Mint (i.e., early Soho, late Soho, and restrike). Early Soho is used to denote coins struck close to the date indicated on the coin; late Soho refers to coins struck at Soho at later date than indicated on the coin; restrike denotes coins struck in the mid-19th century by Taylor using salvaged Soho dies. The fact that the coins typically contained in the shells are “late Soho” pieces provides important information, perhaps the shells too are a later Soho product. Boulton passed away on August 17th, 1809, at 81 years old. Peck makes no mention of when these “late Soho” pieces were struck, so it could have been well after Boulton’s death. Boulton’s son, Matthew Robinson Boulton (hereunto referred to as Matt), had been running the day to day operations of the Soho Mint for some time leading up to 1809. Perhaps maybe it was Matt and not Boulton who came up with the idea for the shells. This is a point that Bill made during one of our conversations. He also made another interesting point about James Watt Jr. and how he had become a partner with Matt shortly after Boulton’s passing. Watt Jr. would later become the Soho Mint master in 1815 and would secure a significant number of contracts for the Mint during his partnership with Matt (Doty, 1998). Watt Jr. may have come up with the idea for the shells, or as Bill suggested, it could have been Matt’s idea that Watt Jr. ran with. The story does not end here though. Bill also pointed out that neither of the Boulton’s were coin collectors, but Watt Jr. was. Watt Jr. likely understood the importance of preserving the specimens in his collection, and it seems likely that he would apply this same level of care to the pieces he produced at Soho. Perhaps Bill is correct, maybe Matt had the idea, and Watt Jr. implemented it. We may never truly know, but for now, it seems that my initial assumption about Boulton’s involvement is less likely. Boulton may not have had anything to with the silver-lined brass shells at all. With a firmer grasp on the “who” question, we can now focus on the “why” question. I already hinted at it, but my second assumption was that the shells were mostly used to house and protect the specimens within the Watt Jr. and Boulton family collections. It makes sense that two families tied to the Soho Mint would want to save a few pieces for themselves. As Bill suggested, Watt Jr. likely took advantage of the fact that the Soho Mint was a private business and struck a few coins he needed for his collection. This would certainly help make sense of all the “late Soho” strikes that Peck (1964) details in his book. Perhaps maybe he then made the shells to keep the coins “as struck” for his collection. Like my first assumption, there is some evidence to support this conclusion. For starters, almost all of the coins that have come up for sale with the shells are traced back to either the Watt Jr. or Boulton family collections. This is also a point that Bill was able to reassure me on given his unique tie to both family collections. Bill’s reassurance would have been enough, but even the few publications with photographs of coins with their shells have provenance back to either of the original collections (Clay & Tungate, 2009; Tungate, 2011). I should, however, note that several coins exist with their shells that are not tied to either the James Watt Jr. or Boulton family collections. I have two such pieces in my collection (pictured above), suggesting that Matt or James Watt Jr. may have sold/gifted a small number of coins in their shells at some point. It could also be the case that the original owner purchased these two examples from the family in the mid-1930s, and the documentation was lost somewhere along the way. I cannot say with any degree of certainty, but for now, it seems as though the pieces I have in my collection likely did not originate from either the Watt Jr. or Boulton family collections. For the sake of clarity, Bill also mentioned that several coins from the Boulton collection did not have shells when he purchased them from the family. A potential example of this is a coin in my collection with a provenance to the Boulton family but without shells. Of course, it could also be the case that the shells were separated from the coin when it was sent in for grading and subsequently have been lost. This is also a mystery that may never be solved. My second assumption seems to be partially correct as nearly all of the coins with their shells are tied back to the two families; however, this assumption is not correct whatsoever when considering the medals struck at Soho. I am not a medal collector, at least not in the way typically encountered within numismatic circles, so this point was lost to me until Bill pointed it out. Bill, however, is a seasoned medal collector, so this was a pattern that he discovered while handling the Boulton family collection. He suggested that perhaps the shells were a way of remarketing otherwise stale inventory. Now it may seem surprising, but not all of the medals produced at Soho were quick to sell. There is evidence to suggest that Boulton was not a massive fan of making medals. Küchler worked at the Soho Mint until death in 1810 and was primarily charged with die-cutting and designing, but he also was the leading artist for the Soho medals (Pollard, 1970). There is some interesting correspondence between Küchler and Boulton, which suggests that Küchler was much more interested in engraving dies for medals than anything else, but Boulton did not realize the same profit on medals as he did with his coinage contracts. Put simply, the medals were difficult to sell and took time away from Kuchler’s efforts from other projects. As noted by Pollard (1970), this is very apparent in the way Küchler was compensated for his work on the medals. He was paid a flat fee for engraving the dies; however, additional money was gained by sharing the profit of any medals that were sold. As Boulton expected, the medals were difficult to sell, and it appears a small quantity of each type remained in stock at Soho well into Matt and James Watt Jr.’s Tenure at the helm. Pictured below is an example in my collection of such a medal that has retained its original shells but has no direct link to either the James Watt Jr. or Boulton family collections. So what might account for the handful of coins and medals with shells and no provenance to either the Boulton family or Watt Jr. collection? My third assumption attempted to account for the coins, but before my conversation with Bill, I was unaware that medals also existed with shells and no provenance. I had assumed that the coins might have been a form of advertisement for the Soho Mint and that perhaps the shells were included to further impress potential clients interested in a coining contract. After all, the shells would have done an excellent job keeping the delicate proofs “as struck”. This still may be true, but the point that Bill made about the medals might suggest another reason for the shells. He suggested that the shells may have been a way of remarketing otherwise stale inventory and thus making them easier to sell. This point seems logical, and there is some evidence to support it. In doing a little research, I found that the medals are encountered more frequently with shells and typically lack provenance to either collection. All of this suggests that maybe the shells were a way for Watt Jr. and Matt to reinvigorate interest in the leftover inventory. Perhaps, in this case, the straight forward answer is the most likely to be true. Given the information I presented, it seems plausible that Matt and/or Watt Jr. are the ones we have to thank for the shells. In my opinion, it also seems plausible the shells were made for several reasons, to protect their collections, to secure future contracts, and to remarket otherwise stale inventory. On any note, I am thankful that Watt Jr. was a coin collector and took such pride in his collection. From what I have gathered, a good deal of his Soho coins came in shells. I find it awe inspiring that at one point each coin was encased within custom made shells and placed in a small piece of parchment with a description of the contents in his handwriting. The 1804 India Pice pictured below is a piece from my collection that has retained its shells and hand-inscribed parchment initially from the James Watt Jr. Collection. This leads me to my most recent purchase, a 1799 proof farthing. This particular example has retained the original silver-lined brass shells and is remarkably well struck with very strong cameo contrast. As you may have already guessed, it is classified as a “late Soho” piece by Peck (1964), which hints at the possibility that James Watt Jr. had this piece struck to fill an empty hole in his collection and subsequently passed an example along to Matt. Or perhaps maybe, a small batch of these coins were struck as specimen examples to gain another coining contract for Soho. We may never truly know why this coin came about, but I take great pride in knowing that I can play some small part in preserving a piece of Soho history that has been passed down through the generations of the Boulton family. Some of you may be wondering why the shells matter so much, and I suppose that is a fair question. The answer, I think, really depends on why you collect coins. I find myself captivated by the history of the pieces and how they relate to contemporary society. As Doty (1998) so eloquently explains, the Soho Mint marked a turning point in the industrialization of money that can still be felt over two centuries later. The silver-lined brass shells, as insignificant as they may be in the larger picture, were likely, in some part, used to preserve that legacy for future generations. I find it essential to preserve the coins, medals, and tokens of the Soho Mint alongside their “original packaging” as @Conder101 so thoughtfully put in one of my earlier posts about the same topic. To me, the little shells are a unique piece of Soho history that is all too often lost in the bigger picture. Please feel free to share any Soho pieces in your collection that have retained their original shells! References Brooke, G. C. (1932). English Coins from the Seventh Century to the Present Day. London: Methien & Co. LTD. Clay, R., & Tungate, S. (2009). Matthew Boulton and the Art of Making Money. Warwickshire: The Barber Institute of Fine Arts. Dickerson, H. W. (1936). Matthew Boulton. Cambridge: Babcock and Wilcox, LTD. At the University Press. Doty, R. (1998). The Soho Mint and the Industrialisation of Money. London: National Museum of American History Smithsonian Institution. Gale, W. K. V., Hist, F. R. S. (1966). Boulton, Watt and the Soho Undertakings. Birmingham: Museum of Science and Industry. Peck, C. W. (1964). English Copper, Tin, and Bronze Coins in the British Museum 1558-1958. London: The trustees of the British Museum. Pollard, J. (1970). Matthew Boulton and Conrad Heinrich Küchler. The Numismatic Chronicle (1966-), 10, 259-318. Selgin, G. (2011). Good Money Birmingham Button Makers, The Royal Mint, and the Beginnings of Modern Coinage, 1775-1821. Oakland, California: The Independent Institute. Tungate, S. (2011) Matthew Boulton and The Soho Mint: copper to customer (Doctoral Dissertation). Retrieved from ProQuest Dissertations & Theses A&I.
