Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used tartar in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are larger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation (1612). It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques of glass formulation like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is reinforced by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular media productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. likewise for physicians that his father idolized like Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used tartar in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are larger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques of glass formulation like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is reinforced by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular media productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. likewise for physicians that his father idolized like Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used tartar in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are larger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is reinforced by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular media productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. likewise for physicians that his father idolized like Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used it in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are bigger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is reinforced by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular media productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. likewise for physicians that his father idolized like Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used it in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are bigger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is confirmed by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular television productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. likewise for physicians that his father idolized like Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Scraping the Barrel

4th century BCE philosopher Diogenes

(supposedly lived in a wine barrel)

by Gaetano Gandolfi (1792)

To seventeenth century glassmaker Antonio Neri, "tartar" was a well-known byproduct of the winemaking process. If we chill wine or grape juice to below 50 degrees (10 deg. C.) crystals of tartar start to form and once they do, then tend not to dissolve back, even at room temperatures. Today, these crystals are commonly found in a powdered form, in kitchen cupboards as "cream of tartar." Bakers and cooks use it to stabilize whipped egg whites, and it has a number of other applications. 

Neri used it in his glass to add sparkle, a trick known to Venetian glassmakers as early as the 1400s. It was obtained from the dregs at the bottom of wine barrels. To understand how this works, it is useful to know that Florentines, Venetians and most southern Europeans made glass from crushed up quartz pebbles or sand mixed with a specific flux known as "glass salt." This salt was rich in sodium carbonates, which greatly reduced the melting point of the quartz. It allowed artisans to work the material at the temperatures easily achieved in their furnaces. Tartar turns out to be very similar, except that it is rich in potassium rather than sodium. 

Potassium atoms are bigger and heavier than sodium atoms and when light passes through a piece of potassium-fluxed glass, it bends and refracts more. This effect is not as pronounced as when adding the even heavier lead to form fine crystal, but it still adds noticeable sparkle to finished pieces. Using all tartar as a flux has the undesirable effect of reducing the workability of the hot glass. Outside the furnace, it becomes stiff quicker and artists have less time to create fancy shapes and forms. The solution to this dilemma is to use a mix of sodium and potassium fluxes together, which is exactly what Neri did. 

In his 1612 book L'Arte Vetraria, he shows how to prepare tartar and then adds it to a number of his glass recipes saying, "The tartar is the secret way to produce more salt and to make cristallo which is whiter and of rare beauty." Here is Neri’s prescription:

To make Purified Tartar Salt you should obtain tartar, which is also called gruma, from barrels of red wine in which it forms large lumps, however do not use powder. Roast it in earthenware pots amongst hot coals until it becomes calcined black and all its sliminess is roasted away. It then will begin to whiten, but do not let it become white, because if you do the salt will be no good.  

Calcine tartar this way: put it in large earthenware pans full of hot common water, or better yet in glazed earthenware pans then made to boil on a slow fire. You should do it in such a way that in two hours the level of the water will slowly decrease to one-quarter, at this point lift it from the fire and leave it to cool and to clarify. Now decant off the liquid, which will be strong lye and refill the pans containing the remains of the tartar with new common water. In the way stated above, boil as before and repeat the procedure until saltiness no longer charges the water. 

At this point, the [decanted] water is impregnated with all the salt. Filter the lye clear and put it in glass chamber pots to evaporate in the ash of the stove over a slow fire. In the bottom, white salt will remain. Dissolve this salt in new hot common water and leave it in the pans, letting it settle for two days. Then filter it and return it to chamber pots to evaporate over a slow fire. In the bottom, a much whiter salt will be left than the previous time. Now dissolve this salt in fresh hot common water and leave it to settle for two days. Evaporate, filter and repeat everything as before. Overall, repeat this procedure four times to dissolve, filter and evaporate the salt of tartar. This will make the salt whiter than snow and purified from the vast majority of its sediment.

When mixed with sifted polverino, or rocchetta, with its doses of tarso [quartz] or sand, this salt will make a frit that in crucibles will produce the most beautiful crystallino and common glass, which one cannot make without the accompaniment of tartar salt. Without it [tartar], good fine crystallino can be made, nevertheless with it, it will be the absolute most beautiful.

*This post first appeared here on 16 May 2014.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"

MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is confirmed by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular television productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen.

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. Physicians like his father idolized Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"

*This post first appeared here on 21 March 2014.

Della Casa's Notebooks Reprise

Spine of volume 3 of Della Casa's notebooks,
Biblioteca Nationale Centrale Firenze.

At the turn of the seventeenth century, when Priest Antonio Neri was employed in Florence by the Medici prince Don Antonio, he worked closely with another alchemist by the name of Agnolo della Casa. Casa chronicled Neri's work and after his colleague's death in 1614, he undertook a special mission for Don Antonio to interview Neri's other associates and uncover the priest's recipe for the philosopher's stone. Don Antonio went as far as consulting a medium in Venice to contact Neri in the afterlife, but that is a story for another time. Here is what I wrote about della Casa last September:

Thousands of pages of notes relating to Antonio Neri's work in Florence were recorded by fellow alchemist Agnolo della Casa. A significant portion of this nineteen-volume transcript is devoted to Neri's work on transmutation and specifically on the fabled philosopher's stone. The trouble is that he wrote much of it in obscure language, which renders it among the most cryptic in the entire canon of alchemy. Other sections of Della Casa's notebooks contain copies of the works of various adepts including Geber, Ramon Llull and Arnold Villanova. Neri took a keen interest in all of them.

In 1597, Prince Don Antonio de' Medici occupied the dormant Casino di San Marco and made it his new home. His father, the former grand duke, built this combination palace and laboratory on the north side of the city to indulge his own fascination with natural secrets. Don Antonio began to assemble a team that included Neri and Della Casa. The three men were all about the same age, in their early twenties, ready to do great things; ready to reveal nature and change the world.

In their time, it was reasonable to think that one metal could be 'purified' into another and that a single medicine could cure all disease or counteract any poison. These notions had been around since ancient times. In this realm, a skeptical eye was an absolute necessity, but there was no specific evidence that disproved the old stories. Don Antonio reportedly spent a fortune collecting recipes and testing them; he and his men worked to separate the real from the bogus. Swindlers and con men were in plentiful supply; they hawked miracle cures in public squares throughout Europe. Without a firm grasp of the underlying chemistry, the task of understanding a particular compound or chemical reaction could be quite difficult. Even to experienced, careful researchers, there was no guarantee that conclusions were correct.

Don Antonio was convinced that the glassmaking priest had indeed discovered the secret of transmutation. He put Della Casa to work interviewing Neri's acquaintances to see what could be learned. An expert gold refiner, Guido Antonio Milani, reported to Della Casa that in July 1596, Neri had performed before his eyes a transmutation of base metal into "twenty-four carat" gold. He said he pressed the 20-year-old, who in reluctance, confided that he had learned the secret from a German, who performed the gold transmutation with a "tablet of medicine." The German told Neri the medicine was nothing but the simple quintessence of green vitriol and the method to produce it was described by Paracelsus.

A Deeper Accomplishment

From Antonio Neri, "Treasure of the World"
MS Ferguson 67, f. 22r.

For the past four centuries, Antonio Neri has been best known as the author of L'Arte Vetraria, the first printed book solely devoted to the art of glass formulation. It is a work committed to the subject of refining raw materials and combining them into a range of glasses, over a rainbow of colors. 'First into print' is a notable distinction, but one that Neri surpasses with ease by a deeper accomplishment. His book provides a rare glimpse of skilled practical knowledge. This was an era when prized techniques were frequently lost to subsequent generations; lost because artisans so often spared the pen. Their precious knowledge went purposely unrecorded, passing in strict confidence from master to apprentice working side by side. Neri preserved the old techniques like no other document has.

That 'first into print' is what we remember him for highlights an age-old problem that dogs historians. It is a simplification that puts a convenient handle on Neri, but at the same time, it de-emphasizes the fact that he was not working alone. It plays into a narrative that history, in general, happens in a parade of discrete jumps due to the brilliant discoveries of individuals working in isolation. This is confirmed by the mythology surrounding Neri – that he was a mysterious lone alchemist, wandering around Europe, evading those who would steal the secret of the philosopher’s stone. A similar narrative is applied to one historical figure after another, a form that is so appealing that it fills many history books of our schoolchildren and dictates the story lines of popular television productions (of a certain ilk) about the history of science and technology.

This is not to deny the limelight to anyone. Neri is a comparatively minor contributor and in my humble opinion definitely deserves recognition and even celebration. The danger is that by reducing history to a list of lone individuals making breakthrough discoveries, we distort the truth of how things are done and more to the point; we miss out on the far richer adventure of what really happens.

Never mind that Neri's book chronicles the work of hundreds or thousands of glassmakers that came before him or that he probably would have been far more grateful to be remembered for his work in alchemy and medicine. What sticks is 'first into print.' The reality is that he had the substantial resources of the Renaissance Medici court at his disposal. There is strong evidence based on his own manuscripts and drawings that he worked among a group of at least a dozen colleagues of both sexes, exchanging ideas, experimenting and urging each other on; a mode that no scientist would deny is far closer to the way discovery and innovation really happen. 

This cultural defect in our perception of history is by no means a recent development. Even in Neri's own time, the early seventeenth century, the 'lone man' paradigm was well established. He and his contemporaries thought along similar lines about alchemists Arnold Villanova, Ramon Llull and Paracelsus. Physicians like his father idolized Galen and Dioscorides.

For the first time in history, we each have a tremendous chunk of the past at our fingertips in the form of the internet. It is a golden opportunity, not to be fed history, but to discover it for yourself and perhaps for the rest of us. There is no shortage of connections yet to be made and libraries around the world are availing their treasures freely to anyone with an interest. For a great adventure and an exercise in critical thinking, pick a discovery attributed to your favorite figure in history and ask the question "on whose shoulders was she standing?"