- Introduction
- Asia / Islam
- Europe & Britain
- French Origins
- Stylus-Quill-Penner
- Early Fountain Pens
- Hawkins-Mordan Patent
- Virginia Roots
- Jefferson Pen Analysis
- American Pencil Makers
- American Gold Pen Makers
- Gold Pen Advertising
- Philip Poole ‘HIS NIBS’
- Inkwells
- Inkwells & Writing Sets
- Writing Sets
- Cyphers
- French Inkwell Makers
Bagley’s American Writing Revolution Contributions
Bagley Patents 1846-1850
Arguably Bagley’s most important contribution to the American Writing Revolution is his 1847 patent no. 6,991.
The patent drawing depicted above looks simple, however; the concept resulted in a major step forward in manufacturing capability. The manufacturing methodology advancement resulted in compact extendible pen and pencil holders that could easily by carried in a pocket.
The manufacturing process included trade secret steps that produced a notably stable instrument offering dependable, easy to deploy pen and pencil holders. Attempts to reproduce the product were met with a quick response. A.G. Bagley vigorously enforced infringement of his patents.
Bagley‘s factory began aggressive sales “to the trade”. By offering fellow Gold Pen nib makers as well as Tiffany & Co. and others an opportunity to market the same extension holder products branded by each Gold Pen nib maker as his own ”branded“ product,
The Bagley factory also offered Gold Pen nib production to others in the Gold Pen nib trade as well as stationers, jewelry retailers, etc., stamped with their own names on Gold Pen nibs.
Bagley operations received orders from around the globe, promptly filling all orders, resulting in millions of Gold Pen nibs and pen & pencil holders flowing into use around the world.
Albert G. Bagley Patents and The American Writing Revolution
Albert G. Bagley Early Successes
Albert G. Bagley apprenticed under pioneer pen maker Levi Brown and worked alongside John Rendell. In 1840, Albert G. Bagley Gold Pens was located at 1 Front St. in Brooklyn, and also 189 Broadway, New York, NY.
The American Institute Fair
The first competition of American Gold Pen nib makers occurred in 1843 at the Fair of the American Institute in New York City.
The American Institute Fair, organized by the American Institute, took place annually in New York City from 1829 to at least 1897. The fair aimed to promote agriculture, commerce, manufacturing, and the arts. Although it was relatively small compared to later world's fairs, it still drew around 30,000 visitors each year. Initially held at Niblo's Garden, the fair was later moved to the Crystal Palace in New York. The fair showcased the best agricultural and manufacturing products of the day.
Levi Brown, listing his manufactory at 10 Front Street in Brooklyn, a silver medal having been awarded for best Gold Pen, was also awarded a diploma.
A.G. Bagley, listing his manufactory at 1 Front Street in Brooklyn, having been awarded for second best Gold Pen a diploma.
Brown and Bagley were recognized separately for their quality gold pen products in 1843 at the Fair of the American Institute. A report stated that Levi Brown, 61 Nassau Street, Brooklyn, was awarded a silver medal for the best gold pen. A. G. Bagley, 189 Broadway, won second best gold pen.
Josiah Hayden won second best Steel Pen specimen in the 1843 American Institute Fair. He sold his Steel Pen nib business to Williston and William Ezra Thayer in 1845 and began Gold Pen nib manufacturing with Rollin L. Dawson.
The Scientific American
A.G. Bagley began advertising his gold pens in The Scientific American in 1845 and continued through the 1840's. When Scientific American publisher Rufus M. Porter began publishing in 1845, he and Mr. Bagley became friends. Bagley pen products were advertised in Scientific American until at least 1850.
The Scientific American reported from New York on March 3rd 1849 regarding the Bagley Gold Pen factory “… It is calculated that 1,200,000 gold pens were manufactured in this country in 1848, and more than 800 pounds of gold used in their manufacture…”
Bagley products were also advertised in New York and later throughout many of the United States. Advertising continued during various partnerships through the 1870s.
Scientific American - September 1846
Albert G. Bagley Gold Pen nib AND patent extension pen holders touted by Scientific American.
Scientific American Marketing Leverage
Albert G. Bagley Gold Pen nib AND patent extension pen holders offered by Bagley “to the Trade”, after mentionaing increased manufacturing capacity by adding “machinery” for the manufacture of Bagley Gold Pen nibs and his first patented extension pen holders.
The additional ad coverage exposure via Scientific American further accelerated the Bagley factory growth.
Bagley Improved Nib Developments
Albert G. Bagley Gold Pen nib production evolved to include the Bagley Improved, Bagley Improved 1 and Bagley Improved 2 Gold Pen nibs. The original Improved Gold Pen nibs are roughly the size of the Improved 2 nib production.
Analysis is underway to determine distinguishing characteristics of each Improved model. Note that the leftmost Gold Pen nib is not marked New York and is slitted deeper than Gold Pen nib on the right.
Depicted are very early Bagley Gold Pen nibs only marked Bagley Improved.
Bagley Improved Nib Developments
Microscopic views of an early experimental Albert G. Bagley Gold Pen nib production Bagley Improved 2 Gold Pen nib.
Analysis is underway to determine the method utilized to apply nib material to this Improved 2 model. This method was not placed into normal production at the Bagley factory.
This Gold Pen nib is identified on the underside as number 658, very early in Bagley Gold Pen nib production numbers attained on an annual basis according to numbers documented in authored content contemporaneous with the historical period.
Bagley’s Revolutionary 1847 Pen Holder Manufacturing Patent
Albert G. Bagley was awarded patents in 1846, 1847, and 1850, related design and manufacture of an emerging writing instrument technology evolution in the United States.
Albert G. Bagley's patent number US4991A, dated February 27, 1847, Forming Metallic Pen-Barrels by Drawing, was a significant innovation in the manufacturing of metallic pen-barrels. Bagley's invention involved forming the barrels by drawing them through a series of dies, which allowed for greater precision and consistency in the manufacturing process.
Bagley's invention had a significant impact on the Gold Pen business penholder manufacturing process, as it enabled the production of more uniform and reliable pen barrels. Prior to Bagley's invention, pen barrels were often made by hand, which resulted in significant variations in size and shape. Bagley's invention helped to standardize the manufacturing process and improve the quality of the final product.
Later patent citations for 20th and 21st century medical field and appliance manufacturing patents further highlight the significance of Mr. Bagley’s discovery.
In addition to its impact on the gold pen manufacturing process, Bagley's invention has also been cited in a number of 21st century Global Medical Field Patents. For example, global patent numbers EP4011303A2, EP3510945A1, and EP3782576A1, each titled "Occlusion Device" and awarded from 2019-2022 and described variously as an implantable device for vessel occlusion or an occlusion device for implantation into a body lumen or aneurysm, each cite Bagley's invention as a foundation reference in the development of a new manufacturing process for life-saving arterial stent components.
Similarly, US patent number US5727581A (now a Global Patent), titled "Dishwasher spray-arm assembly", originally filed by General Electric Company employees in 1996, cites Bagley's invention as a key reference in the development of a new manufacturing process for dishwasher spray-arms, again demonstrating the remarkable foundation of Bagley’s manufacturing process. This patent is mistakenly classified B43K1/04 Split nibs with broadened tips, and is clearly a pioneer status patent.
Patent Cites:
US5727581A *1996-10-021998-03-17
General Electric Company Dishwasher spray-arm assembly
EP3510945A12014-04-302019-07-17
Cerus Endovascular Limited Occlusion device
EP3782576A12016-03-112021-02-24
Cerus Endovascular Limited Occlusion device
EP4011303A22015-12-072022-06-15
Cerus Endovascular Limited Occlusion device
Overall, Bagley's patent number US4991A was a noteworthy innovation in the manufacturing of metallic pen-barrels that enabled Bagley to save time and money in the manufacturing process which resulted in his pen factory producing products for peers cheaper than they could themselves produce. Moreover, its impact can arguably be seen in the Medical and Appliance Manufacturing fields today.
The depicted Gold Pen Extension Holder is the earliest example of patent 4,991 discovered. Constructed of an undetermined metal alloy, the pen holder was equipped with an early experimental bimetallic Gold/Silver nib stamped "Diamond Pointed". The dimensions of this early Bagley Extension Pen Holder are quite small, Closed, 2.25 inches and Extended with nib, 4.313 inches. Note the magnified imagery superimposed on the patent. The rightmost magnified image exhibits the use of a concentric swage tool, a sophisticated technique in the 1840's.
Bagley 1846 Penholder Extension Case Patent
Albert G. Bagley toiled to create his first patented pen hold extension system. Bagley quickly became a Person of Ordinary Skill in the Art or POSITA in the pen holder manufacturing business and his novel designs required trade secret and intellectual property protections. Patent number 4,557, awarded to Albert G. Bagley for Improvement in Pen or Pencil Holders, was a significant development in the pen holder manufacturing business in the United States. The invention provided a compact and reliably deployable Gold Pen nib holder mechanism.
In his first patent of 1846, Mr. Bagley identifies a 2-tube design and accompanying the patent drawing is a photo image of an early 2-tube pen/pencil holder based on the novel design principle. The holder is made of two parts, a cylindrical body with an extendable 2nd section, which are held together by a rivet described within the patent claims. Classified as B43K3/04 Nib holders with retractable nibs.
The example is simply marked Bagley, evidence of pre-patent design work.
The resulting Bagley 2-tube design patent extension penholders were mass produced in the Bagley factory as a result of Bagley’s patent number US4991A, dated February 27, 1847, Forming Metallic Pen-Barrels by Drawing, resulting in the mechanization of the extension penholder manufacturing process.
Mr. Bagley’s efforts resulted in precision, repeatable production of product that was unmatched by other pen makers for many years.
Bagley's 2-Piece Extension Penholders
Albert G. Bagley penholders varied in size and were made of silver, gold, and non-precious metal alloys.
The Bagley extension pen holder was produced in multiple formats, and extensive production was sold to-the-trade, often unmarked as Bagley’s patent product and sometimes marked to identify and commemorate the John Rauch 1852 or John Mabie 1854 patents.
Bagley enforced his co-partnership and employee agreements, and warned of consequences if anyone infringed his patents, offering instead to provide product cheaper than anyone by utilizing his patent methods in precision manufacturing production for sale to-the-trade.
The products depicted are the largest and smallest extension format 2-piece penholders found to date. The depicted examples are pen / pencil combos in sterling silver, however; many 2-piece extension penholders in the collection are gold and a few are plated. The smaller pen holder in the middle is equipped with an early Bagley Improved No. 1 gold pen nib and the large penholder on the right is equipped with a large gold pen nib marked Piquette / Detroit. Mr. Piquette was a trained jeweler working under Brown, departing employment with Levi Brown and establishing his own business prior to Mr. Brown's move to New York.
The leftmost item in this image is a Bagley pen holder in non-precious metal with a Diamond Pointed combination fused gold/silver nib.
Bagley’s 1846 Patent Mark
Many Bagley 2-section extension cases deriving from his 1846 pen holder extension case patent were marked. The depicted mark was placed in a vulnerable area on the pen holder and most were rubbed off.
Durant 1846 Pencil Case Patent
The John Durant patent number 4,602 was awarded June 27, 1846, and immediately assigned to A.G. Bagby (Bagley).
Classified as B43K21/08 Writing-core feeding mechanisms with the writing-cores fed by screws, this is potentially a pioneer status patent.
Little is known about Mr. Durant and research continues to validate that he was an employee at the Bagley factory.
The Durant patent claims “The mode herein set forth of forming a bottle or receptacle for storing surplus leads …”
The Bagley assigned patent number 4,602 was cited or referred to in a patent filing in Germany in 2021. German company Lasos Lasertechnik GmbH was awarded patent number DE102021133024A1 for a Helium-Neon Laser Array with Stable Light Emission on 15 June 2023.
Bagley 1846 Pencil Case Patent
The Bagley patent number 4,840 was awarded November 6, 1846, for a pencil case design. Classified as A45D40/04 Casings wherein movement of the lipstick or like solid is a sliding movement effected by a screw, this patent is a pioneer status patent cited below In 1954.
Bagley claims as novel - “The mode of forming a reserve for leads in the outer or revolving cylinder of the machine by cutting grooves of the periphery of the latter and covering them with an outer casing …”
The Bagley patent number 4,840 was cited or referred to by mechanical pencil manufacturer Scripto in a 1954 patent filing for a Plastic Mechanical Feed Tube (Patent Number US2831459A), awarded 22 April 1958.
Bagley 1850 Penholder Extension Case Patent
Classified as B65D77/0466 Articles or materials enclosed in two or more containers disposed one within another the inner and outer containers being rigid or semi-rigid and the outer container being of polygonal cross-section not formed by folding or erecting one or more blanks the inner container having a polygonal cross-section the containers being mounted on a pallet, this is a pioneer status patent.
Bagley pen holders varied in dimension and type, and were often made of silver, gold, and non-precious metal alloys. Early Bagley penholders were simple dip pen holders of gold or silver with a handle composed of various woods, ivory, or mother of pearl.
The Bagley extension pen holder was produced in multiple formats with the earliest typically the 2-piece type. Extensive production was sold to the trade often unmarked as Bagley’s patent product.
The products depicted are the largest and smallest format extension pen holders found. These are traditional pen / pencil combos in sterling silver. The smaller pen holder in the middle is equipped with an early Bagley Improved No. 1 gold pen nib and the large penholder on the right is equipped with a Piquette of Detroit gold pen nib. Mr. Piquette was a trained jeweler and started a Detroit jewelry business prior to Mr. Brown's move to New York.
Bagley's 2-Piece Extension Penholders
Albert G. Bagley penholders in gold varied widely in engraving teAlbert G. Bagley penholders varied in size and were made of silver, gold, and non-precious metal alloys.
The Bagley extension pen holder was produced in multiple formats, and extensive production was sold to-the-trade, often unmarked as Bagley’s patent product
Depicted are a variety of sizes, up to 7 inches in length without Gold Pen nib or pencil deployed.
Bagley's 2-Piece Extension Penholder
The Bagley 2-piece Extention pen-holder stabilization band is fabricated of an ultra-thin brass strip soldered to the top of the lower section.
The brass band is slotted and expanded to form an adjusting sprung expansion band at the top of the lower section , thereby dramatically reducing or eliminating the wobble of the lower section as it is slid in and out of the upper section.
The extention pen-holder used to illustrate this function had been heavily used and the swaged ring (see Bagley 1847 patent) at the bottom of the upper section had partially broken away.
This stabilization methodology may be one of the trade secret steps mentioned in the Washington Weekly National Intelligencer 1851 article detailing the Bagley factory operation.
See https://portecrayons.com/bagley-manufacturing
Bagley's 3-Piece Extension Penholders
Albert G. Bagley so-called double extension penholders were produced and sold directly to customers and to-the-trade, marketed with Bagley Gold Pen nibs or with other Gold Pen nib makers’ nibs.
Depicted are a variety of sizes, up to 7 inches in length without Gold Pen nib or pencil deployed.
Bagley's 1850 Patent Penholders
Albert G. Bagley penholders varied in size and were made of silver, gold, and non-precious metal alloys.
The Bagley extension pen holder was produced in multiple formats, and extensive production was sold to-the-trade, often unmarked as Bagley’s patent product and sometimes marked to identify and commemorate the John Rauch 1852 or John Mabie 1854 patents.
The products depicted are several examples of Bagley’s extension format 3-piece penholders from the collection. The depicted examples are pen / pencil combos in high carat gold, however; some 3-piece extension penholders in the collection, as illustrated above, are sterling silver production.
Note that the carnelian ball pen top mounts are all slightly different patterns, indicating single item production.
John Loring’s Prediction
John C. Loring Legacy
John C. Loring was a noted collector in numerous genres including writing instruments of the world. Sadly, his website is no longer functional, for it was a valuable resource for collectors. Mr. Loring authored one of the first reference books cataloging early American writing instrument patents along with photos from his collection as well as other writings. John was a passionate believer that the writing instrument revolution in America was a yet untold story. He was a kind and supportive mentor to many.
He authored at least two thoughtful articles for Stylus Magazine. In the December/January 2004 issue titled "The Birth of American Writing", within which Mr. Loring opined on page 29... "How the wondrous combos of Mabie Todd and Rauch emerged from this crude background [both were trained pencil makers] in so few years is unreported, leading me to explore the early development of writing implements in America.".
As I read Mr. Loring’s article, more questions arose. After reading on page 39 of the article about a sketch shared with Loring by collector Susan Hale about a silver combo extension pen holder that was identical to Mabie Todd pieces but marked with Bagley's 1850 patent, Loring opined that no example of the sketched pen holder was to be found that proved Bagley was the original designer/maker of such an instrument.
The early silver 3-piece Bagley penholder (photograph atop the above drawing) is part of this collection and clearly marked "Patented Jan 1 1850". This silver penholder verifies that the “Mabie Todd bullet-shaped" middle extension case combo drawing accompanying his 1854 patent was indeed a pen holder originally created by Albert G. Bagley years prior to John Mabie filing his patent. Mabie was simply identifying prior art in his patent drawing and stated such in his patent language.
Mr. Bagley's 1846, 1847, and 1850 patent awards elucidate the foundation of the origins of the American extension penholders found today.
Included among the items depicted and referenced within this website are many Loring collection items. Mr. Loring’s extensive Bagley collection was a stimulus for research and development of this collection.
Mabie Figures 1, 2, & 3 = Prior Art
The Mabie 1854 Patent No. 11,762 Drawing - Fig. 4 (Red Circle)
John Mabie included a drawing of the Bagley extension penholder as part of his 1854 patent. He did NOT claim to have invented Mr. Bagley’s extension pen holder but merely to explain how his pencil extension improvement was used within the Bagley pen holder In Fig. 4 of his drawing.
Within his patent 11,762, Mabie identifies CLAIMED AS NOVEL - “What I do claim as new, and desire to secure by Letters Patent, is -
Operating the pencil slide E as herein shown …” Fig. 4 within the patent drawing is the actual John Mabie patent improvement to the pencil.
Mabie continues by identifying NOT CLAIMED AS NOVEL AND RECOGNIZED AS PRIOR ART -
“I do not claim, therefore, operating the pencil-slide by a single spiral slot cut in a movable or rotating tube; neither do I claim operating the pen-slide as herein shown, for they have been previously used …” The pen-slide is the previously patented Bagley extension pen depicted in the Mabie drawing as Fig 1, Fig 2, and Fig. 3, and is identified as prior art, having been previously invented.
This Mabie patent claims an improvement to the Bagley pencil extension mechanism in Fig. 4 of the patent drawing, illustrating the Bagley penholder depicted in the photo as the target of improvement.
John Mabie produced a depiction of the Bagley extension penholder for his lone novel patent, however; it was simply for an improvement to an extant Bagley pencil extension mechanism.
The various Mabie co-partnerships and advertising generated substantial business only after son George Mabie's novel designs and patent awards arrived between 1875 and 1902.
Bagley’s Historic Appellate Cases
To Those Who Would Infringe:
Albert G. Bagley factory production was offered “to-the-trade” for retailers.
He began newspaper advertising of his new patent extension pen holders in April 1846.
Bagley was not only proactive regarding legal adherence to his employee and co-partnership agreements.
He also repeatedly warned his peers that purchasing wholesale from his pen holder factory was preferred and benefitted all parties.
Mr. Bagley further warned that infringement would be prosecuted to the full extent of the law.
Bagley’s courtroom record served to demonstrate that he would follow through on the warnings. A key example provides insight into actions that await anyone treading into patent infringement or trade secret theft is Bagley’s appeal reversal of a judicial decision in favor of an employee who had agreed to protect such secrets.
In Bagley v. Clarke, the judicial panel agreed that Bagley’s patent and trade secrets were to be protected…
“The necessity of secrecy on the part of Clarke, as to Bagley's improvements, inventions, or discoveries, still continued, and it is almost absurd to suppose that either party imagined that this important covenant was abrogated by the change of compensation [provided to Clarke]…
Clarke did not change masters in working for the new firm. He was not employed by the new firm. He was still under Bagley's orders, and Bagley's directions to him to work for his new firm were no more than he had a right to give under his agreement with Clarke.
To hold this agreement rescinded, would be to leave Bagley in a worse position than he was in when it was made, for he [Bagley] would have introduced a workman into the secrets of his art, without any guaranty against his disclosing them; and this was considered by both parties as of such vital importance that it was expressly provided for in the original agreement. It is a rule that one party cannot rescind a contract, unless both can be left in the condition in which they were before the rescission…
Will the court seriously hold that this agreement was fully executed when the first one hundred pens were polished and paid for, and that if Clarke had the next day revealed all the secrets, which he had by covenant bound himself not to do, Bagley would have had no redress?
The question should never have been taken from the jury” [and Bagley won the appeal].
Bagley‘s Historic Milestone in Trade Secret Law
Historic Milestone in Trade Secret Law: The 1857 Bagley v. Peddie Case
Exhibited is a Gold Pen nib stamped “Peddie’s Manuscript Pen“ produced by Charles B. Peddie, who was taught the Bagley Gold Pen manufacturing process as a journeyman apprentice beginning in 1844. The Gold Pen nib is mounted in a Bagley 1846 patent 3-section pen & pencil holder, also mounted with a Bagley pencil. The overall length of this pen with Gold Pen nib extended is 7.5 in.
Cited by multiple trade secret experts is Albert G. Bagley‘s pursuit of apprentice employees who violated their bonded indenture agreements. On September 6, 1857, a pivotal moment in the early development of American trade secret jurisprudence unfolded in the case of Bagley v. Peddie, 16 N.Y. 469 (1857).
Albert Bagley, a prominent manufacturer of gold pens, filed suit against his journeyman, Charles B. Peddie, marking arguably the earliest judicial recognition of trade secret protection under contract law.
Bagley and Peddie had entered into a formal agreement in which Peddie committed to a four-year term of employment. Critically, the agreement included a confidentiality clause requiring Peddie to maintain secrecy regarding Bagley’s proprietary methods for gold pen manufacturing and to refrain from disclosing any improvements or inventions developed by Bagley.
When Bagley suspected that Peddie had breached this obligation by revealing confidential manufacturing techniques, he invoked a contractual provision stipulating $3,000 in damages for such a violation. The legal dispute centered on whether this sum constituted an enforceable liquidated damages clause or an impermissible penalty.
Initially, the trial court ruled against Bagley, reasoning that damages could be determined by a jury and thus the clause functioned as a punitive measure. However, the New York Court of Appeals reversed this decision, noting the inherent difficulty in quantifying losses resulting from trade secret misappropriation. The court emphasized the practical challenge of proving actual damages in such cases and held that the $3,000 amount was a reasonable pre-estimate of potential harm, thereby validating it as liquidated damages. As a result, Bagley was granted a new trial.
This landmark ruling underscored the unique evidentiary difficulties in trade secret litigation and set an important precedent for the enforceability of contractual remedies in cases involving the disclosure of confidential commercial information.
Peddie Gold Pen Production
Charles B. Peddie continued production of his Gold Pen nibs from at least as early as December 1849. He was listed at the Bagley Gold Pen Factory at 189 Broadway In 1846, during the co-partnership with the Smith’s.
Peddie Gold Pen
Advertising in March 1850 informs us that Peddie, located at
No. 2 John Street in New York, thought of himself as a thorough mechanic.
Peddie’s Manuscript Pen
Peddie Gold Pen nib production was ongoing from December 1849 until his suicide death by Prussia Acid in 1854 for pecuniary reasons.
The depicted Gold Pen nib is stamped “Peddie’s Manuscript Pen”, is of good quality thickness and well pointed with iridium, indicating that he was taught well as a journeyman in the Bagley factory as an apprentice.
Bagley v. Peddie
Peddie was accused by Mr. Bagley of violating the terms of his journeyman apprenticeship and asking for payment of $3,000. The Court disagreed with Bagley, however; an Appellate decision later overruled the decision and provided for a new trial.
Peddie in Philadelphia
Peddie sought a new start in Philly, establishing his Gold Pen Manufactory at No. 159 Chestnut Street. He styles himself as “late of the firm of G. & E.M. Smith”, a potentially disastrous move since the Smiths were also sued by Bagley and liquidated for violating the co-partnership agreement with Bagley.
Peddie‘s Philadelphia Fire
On January 13, 1852, Peddie or one of his workmen left coal smoldering in a forge at the Chestnut Street address resulting in damage and losses.
Peddie Adamantine Pen
Peddie advertised “Peddie’s Adamantine Gold Pens” until May 1853.
I am not aware of any examples in a collection.
Peddie’s Death by Prussic Acid
Peddie died by his own hand, committing suicide on December 23, 1854, due to “pecuniary difficulties”.
Prussic acid, also known as hydrocyanic acid or hydrogen cyanide, is a highly toxic substance with various uses including case hardening metals.
Mid-19th-century workshops had minimal safety protocols.
• Journeymen or Manufacturers (e.g., Charles B. Peddie) could be exposed to low-level cyanide fumes, particularly during:
• Improper mixing of acid and cyanide
• Heating of cyanide salts
• Cleaning or stripping of metal parts
• Such environments presented chronic exposure risks and were sometimes sites of accidental or intentional poisonings using available chemicals, including Prussic acid.