Bacon and the art of living 2. the saltpeter letter

July 1891


When you were small and I read to you and Lauren, The Adventures of Tom Sawyer, before bed-time,  we all had our favourate parts.  I memorised this one. “He had discovered a great law of human action, without knowing it–namely, that in order to make a man or a boy covet a thing, it is only necessary to make the thing difficult to attain.” (Twain, 1876: 13)

Curing good bacon is difficult to get right, especially since we did not grow up with the knowledge.  As Tom learned, this fact does not put us off.  It makes us want it more!  This is the reason why I am here in Denmark.

I miss our weekly hikes up Table Mountain and the kids in Denmark don’t have mountains like we have in the Cape.

What I miss even more is having you here so that we could learn together.

Every night after supper Andreas’ dad reads for us from a book called Foods, written in the 1870’s by an Englishman, Edward Smith.

I want to give you a few quotes from this book that will show you why what we are doing is important.

Curing bacon is in the first place about preserving food and getting it right is in the interest of the great powers of this world.  Edward Smith says in his book that “the art of preserving meat for future use, with a view to increase the supply and lessen the cost of this necessary food (meat), is of very great importance to [England] and all the available resources of science are now engaged in it.” (Smith, 1876: 22)

pig stay

He lists the main ways that this is being done namely by drying, by cold, by immersion in antiseptic gases and liquids, by coating with fat or gelatin, by heat, salted meat and by pressure. (Smith, 1876: 22 – 38)  Tris, this list is important.  All have their benefits and disadvantages.  As science develops in each area, the main way of preserving meat may change.  Never continue to do things because we did it in a certain way.  Always remember this list and see if it is not time to change the entire way things are done.

Edward Smith says that pork is particularly prized over beef and mutton because “in such localities the pork is always pickled and kept ready for use without the trouble of going to the butcher, or when money could not be spared for the purchase of meat.”  (Smith, 1876: 59)

Bacon is made when cuts from the pig is preserved by salt and saltpeter.  (Smith, 1876: 64).  This gives bacon its characteristic pinkish/ redish colour, a nice flavour, and it lasts a long time before it tastes “off”.

This is the kind of things we learn at night, after a good supper and we talk about for another hour before we all go to bed.

The next day we leave for work very early.  The owner of the butchery where Andreas works is an older Danish man called Hendrik Jeppeson.  We call him Jeppe.

An extremely knowledgeable man who seems as if he has been around in the meat industry forever.  I have not asked him any question that he did not know the answer to.

Take saltpeter for example.  We use it to cure the bacon with, but what is it?  What is turning the meat redish/ pinkish?  What is preserving the meat and gives it the nice taste?

David Graaf uses too much salt when he cures bacon.  One of the mixes that we use over here is 10 pounds salt and 3 ounces saltpeter. (1)  (Dunker and Hankins, 1951:  6).  We also add other ingredients that I will write you about that David does not know about.

I asked Jeppe these questions about saltpeter one morning.  He put his arm around my shoulders and told me that there are interesting answers to these interesting questions.  That he hopes I paid attention in chemistry class in school.  For the next week, every afternoon when we break for lunch, I would go to his office where he would take out his lunch that he brought from home and while he eats it, he would tell me the story.

He told me that 1891 was a very interesting year that I chose to come to Denmark.

Jeppe has a young biologist friend, working for the German government, Dr. Ed (Eduard) Polenski (9).  It was not long before I arrived in Denmark when Jeppe met up with him in Dresden where he told Jeppe about some amazing findings he had made when studying curing brines and cured pork cuts.

One of the most abundant elements on earth is nitrogen (N).  (2)   Most of what we breath is nitrogen gas. (Wikipedia, nitrogen)

The close relative of nitrogen that Ed found in the curing brine and the pickled meat is called nitrite. (4)  Nitrite has one nitrogen atom and two oxygen atoms (NO2).  What was interesting was that when the brine was mixed and he tested it, there was no nitrite present.

The only family member of nitrogen that was in the brine was nitrate.  Nitrate has one more oxygen atom than Nitrite.  One nitrogen and three oxygen atoms (NO3).

So, he mixed the brine and found nitrate in it.  Then, after a week when he tested it again he found no nitrate, but nitrite was present.  The conclusion was that the nitrate had turned into nitrite. (10)

He thought that small, microscopic organism’s called bacteria were responsible for changing the nitrate into nitrite by using an oxygen molecule from the nitrate.  (Kocher and Loscalzo, 2011 :  71) (4)

Jeppe sat for a long time after he told me how Ed found only nitrite in the brine. (5)

He laughed and exclaimed in his Danish accent, “Bloody hell Eben!  Do you know that Ed is probably right when he thinks that bacteria were the agent responsible for changing the nitrate into nitrite.  Those little buggers probably need the oxygen to live!  The bacteria are so widely distributed in nature that it is hard to find an environment where they are not present.   (Jones, Osman, 1933:  140)

Jeppe sat forward in his chair.  Moved closer to me and said in a soft voice: “I am getting ahead of myself.  The story of saltpeter goes back much further than what Dr. Ed Polenski found.”  He then got up and sat behind his desk.  Out of a drawer he took a big notebook with pages of notes in his own neat handwriting.

“Before Dr. Ed Polenski came around, we did not know what in saltpeter was responsible for the curing of the meat.  For thousands of years!”

All over the world, from Mesopotamia to China, they knew about certain potent salts that change the colour of the meat to redish/ pinkish and gave it longevity!  (Pegg and Shahidi, 2000:  7).  The reddening effect of saltpeter in meat curing was well known in late Roman times (Drs. Keeton, et al;  2009)

These ancients could not tell if saltpeter occurred naturally or was it something that had to be nourished or cultivated by humans.   They wondered how to take the impurities out of the salt.

Nobody could explain its energy.  It was used to cure meat in almost every great civilisation of the world.  The Chinese and Italians used it to make gunpowder.  There is record of gunpowder being used in India as early as 1300 BCE, probably introduced by the Monguls.  (Wikipedia. History_of_science_and_technology_in_South_Asia) It was used since ancient times as medicine and as fertilizer. (Cressy, David, 2013:  12)

Saltpeter was used in ancient Asia and in Europe from the 1500’s to cool beverages and to ice foods.  “Essentially, during the process of the saltpetre dissolving in the water the energy needed to break the bonds of the salt pulls heat from the surrounding water, thus decreasing the overall temperature in the basin”.  (Reasbeck, M:  4)

The first reported references to the characteristic flavor of cured meat produced by the addition of saltpeter during meat preservation and curing were made as early as 1835.  (Drs. Keeton, et al;  2009)

One magical substance called saltpetre!   “Some speculated,” Jeppe continued, “that it contained the Spiritus Mundi, the ‘nitrous universal spirit’ that could unlock the nature of the universe!”

Jeppe had neatly written down a quote from Peter Whitehorney, the Elizabethan theorist who wrote in 1500’s.  He said about saltpeter, “I cannot tell how to be resolved, to say what thing properly it is except it seemeth it hath the sovereignty and quality of every element”.

Paracelsus, the founder of toxicology who lived in the late 1400’s and early 1500’s said that “nitrite is a mythical as well as chemical substance with occult as well as material connections.” The people of his day saw  “a vital generative principle in saltpetre, ‘a notable mystery the which, albeit it be taken from the earth, yet it may lift up our eyes to heaven’”   (Cressy, David, 2013:  12)

Jeppe got up from behind his desk and put the note book open in the palm of his one hand.  He was pacing up and down inn front of his desk as he continued to read quotes.

From the 1400’s to the late 1800’s scientific writers probed the properties of this magical compound.  He continued with a list of quotes.

“Saltpeter encompassed the “miraculum mundi”, the “material universalis” through which ‘our very lives and spirits were preserved.  Its threefold nature evoked ‘that incomprehensible mystery of … the divine trinity,’ quoting Thomas Timme who wrote in 1605, in his translation of the Paracelsian Joseph Duchesne. (Cressy, David, 2013:  14)

“Francis Bacon, Lord Chancellor and Privy Councillor under James I, described saltpeter as the energizing “spirit of the earth.””   (Cressy, David, 2013:  14)

“Robert Boyle who did experiments trying to understand saltpeter found it, ‘the most catholic of salts, a most puzzling concrete, vegetable, animal, and even mineral, both acid and alkaline, and partly fixed and partly volatile.  The knowledge of it may be very conductive to the discovery of several other bodies, and to the improvement of diverse parts of natural philosophy” (Cressy, David, 2013:  14)

Tris, by this time I was completely dumbstruck!  A salt that I have been using almost every day since I landed in Denmark!  A sensation of awe and grandeur came over me!  As if I stepped onto a stage where a Shakespearean drama has been acted out and became part of history.  I would never again hold it in my hand and think of it in the same way!

In India they mined saltpeter from the earth and thousands of small villages were engaged in its production.  (Crookes, W.  1868/ 69:  153)  It grew like fungus on the walls of cellars and around toilets.  (Drs. Keeton, et al, 2009:  6)  (6)  It seems as if it occurs wherever urine and dung occurs such as in bat caves.

LEAD Technologies Inc. V1.01
British Indian Empire

Jeppe continued unabated.  “In Germany they developed technology whereby they created their own saltpeter.   So versed in its production was the average person in Germany that authors in this time did not even bother to detail the processes.”

Lazarus Ercker (1530-1594), chief master of the mines of Emperor Rudolph II in Bohemia, wrote arguably the most detailed account on the production of saltpeter in ‘The right and most perfect way of the whole work of saltpetre’.   A German translation appeared in Prague in 1574 and in Frankfurt in 1580.  (Cressy, D.  Saltpetre, State Security, and Vexation in Early Modern England:  5)

Still, despite the impact of the renaissance and tremendous advances in fields of biology and the natural sciences, people could only appreciate saltpeter by what it did without any understanding of how it worked.  (Cressy, D.  Saltpetre, State Security, and Vexation in Early Modern England:  5)

In the late 1770’s a chemical instructor said about saltpeter:  “‘we are much in the dark as to the origin and generation’ of saltpeter, though he knew it to be ‘found among earth and stone that have been impregnated by animal and vegetable juices susceptible of purification, and have long been exposed to air. . . . It is the product of the elements deposited in the bosom of the earth, and may not be improperly called the universal and unspecific mercury”.  (Cressy, David, 2013:  14)

“Written knowledge of saltpeter filtered into England in 1540 with Vannoccio Biringuccio’s De la pirotechnia.  This work was eventually translated into English and included accounts of the making of explosives. (Cressy, David, 2013:  14)  Saltpeter being one of the main ingredients in gunpowder.

Saltpeter occurs naturally.  In countries with a warm climate and high rainfall, “ammonia resulting from the putrefaction and decay of nitrogenous materials is washed into the soil by rainfall, to be oxidized by bacteria, yielding nitrate. . .  In countries like India, saltpeter is leached from the ground as sheets of water left by monsoon flooding evaporate. A crust of saltpeter, including mineral salts, spreads across the ground, and can be dug up and refined into pure potassium nitrate.”  (Frey, James W.   2009)

Saltpeter was also made by human endeavour.  Where the people of Germany chose to make their own saltpeter, in England they harvested saltpeter earth and extracted it from the niter enriched soil.  Saltpetermen scoured the English countryside and dug up any place where the ground could have been impregnated with animal and human urine and dung.

German Niter beds.
Figure 2: Saltpeter plant: (16th century) Long rows of beds with porous walls(C), filled with a mixture of vegetable wastes, blood and dung as nitrogen source plus lime or ash to promote nitrification. Lime controls an optimum pH-value of 7.2 to 7.8. The porous walls of the beds allow an easy access of oxigen. In building (B) the contents of the ripe salpeter-beds were leached and saltpeter kristallised. (A) A vat, collecting rainwater from the roof. O. Guttmann:”Monumenta Pulveris Pyrii”, London 1906. A collection of Reproductions of Ancient Pictures Concerning the History of Gunpowder.

This was in the first place not used to cure meat, but in the production of gunpowder and as a fertiliser to increase crops to feed the ever growing population of the world.  It was the arms-race of the 16th 17th and early 18th  century and the desire of all great nations.

Peter Whitehorn, the Elizabethan theorist said that saltpeter ‘is a mixture of many substances, gotten out of fire and water of dry and dirty ground.’    It could sometimes be found as an efflorescent or ‘flower that growth out of new walls, in cellars, or of that ground that is found loose within tombs or desolate caves where rain can not come in.’  But saltpeter could also be nourished or encouraged to grow by adding ‘the dung of beasts’ to the earth.  A distinction was made between ‘natural saltpeter’ which only needed to be scraped from walls, and ‘artificial saltpeter’, which required digging and refinement.  The two kinds ‘partook of the very same virtue’ (according to Whitehorn, relaying Biringuccio) except that some /beasts, converted into earth, in stables or in dunghills of long time not used”. (Cressy, David, 2013: 16)

Saltpetermen received authority from the king to dig up any soil from which saltpeter could be extracted to the great frustration of the people of England.  Their work and the irritation it brought to the English people became a huge political issue during the time when England was a monarchy and after the civil war.

Dove coves or pigeon houses were also favourite sites because of their concentration of the sheltered droppings.

“A skilled prospector would know how to soil rich saltpeter for ‘by the taste of the tongue it may be felt if it be biting, and how much”.  (Cressy, David, 2013:  16)

The way it was harvested is very interesting.

Barrels of niter rich soil was harvested in England from places where saltpetre would most naturally occur and in Europe, from niter beds made by the farmers.

In 1588 a man by the name Lucar wrote in Collequies Concerning the Arte of Shooting in Great and Small Peeses of Artillerie, ““digging the earth out of floors in cellars, vaults, stables, ox-stalls, goat or sheep cotes, pigeon house, or out of the lowermost rooms in other houses.”  This reflect the practice in Tudor England’s roving saltpetermen” but in continental Europe “they worked on enriched nitrite beds (managed heaps of vegetable matter mixed with excreta and ordure).  (Cressy, David, 2013: 17)

Barrels full of dung rich earth would be set on a framework so that water introduced at the top would trickle down to a catchment tube at the bottom.  Further refinement through filtration.  The whole process would take a week or more.  (Cressy, David, 2013: 17)  Europe and England struggled to produce enough salptere.

After 1850’s the East Indian Company solved the supply problem of Saltpeter by importing it from India where it occurred naturally and was also efficiently produced. (Cressy, David, 2013:   25)  Some of the saltpeter were imported in a refined state and some to be refined in England.

Trade in saltpeter from India to London, Amsterdam, Lisbon and Stockholm and to my current home city, Copenhagen dominated.  Saltpeter was one of the largest commodities by volume for the Dutch East Indian Company.  (Frey, James W.   2009.) (7) Its ships that sailed past our Cape Town brought tons of unrefined saltpeter to be sold the England and European countries.

The state of ignorance as to the workings of saltpeter continued until in France, Antoine Lavoisier wrote in 1777 his groundbreaking works Instruction sur l’établissement des nitrières et sur la fabrication du salpêtre, and  publiée par ordre du roi, par les Régisseurs généraux des Poudres & Salpêtres where the link with nitrogen was made.  The breakthrough came in 1770 when he analysed nitric asset as a component of saltpeter. (Mauskopf, MSH.  1995:  96)  

digging for saltpeter
Saltpeter digger braking open the floor of a stable with a pick axe.

Lavoisier became the father of industrial chemistry.  By the time of his death a good understanding of saltpeter’s chemical origin had been achieved.  (Mauskopf, MSH.  1995:  116)  The mystery was unraveled.  The mysterious compound – potassium nitrate (3).  It is the nitrate in Saltpeter that was turned into nitrite in Dr. Polenski’s experiments by  the action of bacteria that is responsible for the curing of meat.

Jeppe concluded on a high note.  “The magical salt of antiquity has been identified by modern science and to this day scientist everywhere are trying to unlock the mechanics of how nitrite changes pork into bacon.”

The lunch hour in Jeppe’s office seemed too short.  He told me that this is a small part of the story.  Discoveries in a desert in Chile lead to war over saltpeter.  How did Ed Polenski know that bacteria was changing the nitrate into nitrite?  What was the relationship between salt and nitrite?  Could we use only the nitrite to cure meat and leave out the salt altogether?  How could we reduce the saltiness in the bacon?

At this point I am thinking of another quote from The Adventures of Tom Sawyer .   “When one writes a novel about grown people, he knows exactly where to stop–that is, with a marriage; but when he writes of juveniles, he must stop where he best can.” (Twain, 1876: 208)

I promised Jeppe that I would bring his notebook back by the end of the day.  The sun is setting and I don’t want to be out too late after dark.

This seems to be a good place for me to end my letter to you.  Next week-end I will write again and tell you more.  I am sure that if Ava is reading you this letter, that you must be fast asleep by now!

I hope you are well my boy and that you continue to work hard at school!  Please be sure to keep an eye on your sister.  Remember that while I am gone you are the man of the house and you must take care of the woman.

Be well my boy!

Lots of love, from Denmark

Your Dad.

Bacon and the art of living Home Page

(1)  Even though the survey was done in the 1950’s in the US, 60 years after the letter was presumably written, I include it since methods and formulations in those days seemed to have a longevity that easily would have remained all those years later.  The survey was also done among farmers, in an environment where innovation are notoriously slow.

(2)  Nitrite occurs in nature as gas with two atoms joined together (N2).  It forms about 78% of Earth’s atmosphere (Wikipedia, Nitrogen)

(3) Polenski discovered that nitrates were reduced to nitrites through bacterial action and probably performs the curing function.  Today, nitrites are added to the brine mix as sodium nitrite (NaNO2).  Saltpeter or potassium nitrate is still being used as curing agent in some parts of the world in some dished.  Before curing can take place, bacteria reduces the nitate to nitrite.

(4)  Qualitative and quantitative techniques for measuring nitrite and nitrates in food has been developed in the late 1800’s.  (Deacon, M;  Rice, T;  Summerhayes, C,  2001: 235, 236).  The earliest test for nitrites is probably the Griess test.  This is a chemical analysis test which detects the presence of organic nitrite compounds. “The Griess diazotization reaction on which the Griess reagent relies was first described in 1858 by Peter Griess.” (wikipedia, Griess_test)

Schaus and others puts the year of the discovery by Griess as 1879.  According to him,  Griess, a German Chemist used sulfanilic acid as a reagent together with α-naphthylamine in dilute sulfuric acid.  In his first publication Griess reported the occurrence of a positive nitrite reaction with human saliva, whereas negative reactions  were consistently obtained with freshly voided urine specimen from normal individuals.   (Schaus, R; M.D. 1956:  528)

(5)  Brine is a solution of salt in water.  (Wikipedia. Brine)

(6)  Wall saltpeter (calcium nitrate), formed by nitrifying bacteria and found as an efflorescence on the walls of caves and stables, was gathered in China and India long before the Christian era. (Drs. Keeton, et al, 2009:  6)

(7)  “BETWEEN 1601 AND 1801, ships made thousands of voyages carrying goods from Asian ports to the primary European markets for East Indian commodities: Amsterdam, London, l’Orient, Copenhagen, Lisbon, and Stockholm. On average, these Indiamen measured 1,000 tons burden, with approximately 2,830 [m.sup.3] of cargo space. Sixteen percent of this cargo space, according to the normal practice of East India captains, consisted of saltpeter–some 452.8 [m.sup.3] of nitrates, weighing 1.6 metric ton”  (Frey, James W.   2009)

The British took over the Subah of Bengal from the VOC in 1757.   “The subsequent defeat of a VOC expeditionary force at Bedara in 1759, and the British defeat of the Mughals at Buxar in 1764 secured Company control over Bihar and permitted the monopolization of the saltpeter trade. The significance of these events cannot be underestimated. By seizing Bengal, the British exerted mastery over 70 percent of the world’s saltpeter production during the latter part of the eighteenth century.”  (Frey, James W.   2009)

(8)  One of Lavoisier’s major achievements of the 1770’s (and the one of particular interest to us) : the analysis of nitric acid.”  (Mauskopf, MSH.  1995:  96)

“Lavoisier’s chemical discoveries and reformulation, enabled him to delineate the chemical reaction that produced (explosive) gases : between the nitric acid component of saltpeter and the carbon in the charcoal.” (Mauskopf, MSH.  1995:  105)

He wrote the landmark paper in the spring of 1776 “in which Lavoisier demonstrated that nitric acid was a compound of nitrous gas with « la portion la plus pure de l’air » (the portion of the pure air) by decomposing the acid into these gases and then reconstituting it from them, and asserted for the first time that this « purest portion of air » was a constituent of all acids and a principle of acidity.” (Mauskopf, MSH.  1995:  107)

“Saltpeter is a « borderline » substance between the organic and the inorganic world. Although clearly a neutral salt like other mineral salts, it only seemed to come into existence in the presence of organic substances in a state of decay. There was therefore
a debate in the century before Lavoisier took up the subject over how this substance originated and whether or not vital processes were essential for its formation.”  (Mauskopf, MSH.  1995:  108)

“According to Macquer, three theories were current. The oldest one posited a non-vital origin of saltpeter (or at least of nitric acid) in the air. The other two, formulated in the eighteenth century, related nitric acid’s origin to organic processes. Lemery the younger
postulated a completely organic origin : nitric acid developed in vegetable and animal substances. The theory of Georg Ernst Stahl, was, in a sense, the mean between the other two vis-a-vis organic and inorganic origins; moreover, it offered a chemical analysis
of nitric acid. To Stahl, this acid was a compound of the universal acid (vitriolic) and phlogiston. Although the source of vitriolic acid lay in the ambient air, this acid could only be converted into nitric acid through the agency of organic putrefaction, which liberated
the necessary phlogiston.”

“The origin and chemical nature of the fixed alkali component were only somewhat less obscure than that of nitric acid. « Fixed vegetable alkali » was one of a class of three alkaline substances (the other two were mineral and volatile alkali) that possessed many
common features. Two of these alkalis (vegetable and volatile) were thought to have organic origins while the mineral alkali, or, at least, its principal salt, common salt, was felt to be, in Macquer’s words, « une production de la nature, & […] il n’appartient ni au règne végétal, ni au règne animal, on le range dans la classe des minéraux. C’est par cette raison, qu’on a donné à son alkalile nom iTAlkali minéral » (a production of nature, and […] it does not belong to the plant kingdom or the animal kingdom, it is stored in the class of minerals. It is for this reason that we gave his name alkalile iTAlkali mineral)

. While alkalis, like acids, were distinct chemical substances operationally, they were not yet ontologically separate (nor would they be fully for Lavoisier).” (Mauskopf, MSH.  1995:  108)

“Lavoisier succeeded both in decomposing nitric acid with mercury into its components gases in succession (the rudy « nitrous gas » and then « la portion la plus pure de l’air » (the portion of the pure air) from the calx of mercury which had formed in the meantime) and in reconstituting the acid from just these components gases over water. With this analysis, Lavoisier was moving towards a clear differentiation of acids into chemically distinct species (albeit with a common « acidifying principle », a point also enunciated in this paper for the first time).” (Mauskopf, MSH.  1995:  108)

“By 1777, Lavoisier had reached the conclusion that the traditional (i. e. Macquerian) view of the role of the wood-ash treatment was indeed correct : it was necessary to employ wood-ash preferably both intermixt with saltpeterish earth and as a lessive in that earth’s first purification. His conclusion was based on systematic study of the tamarisk ash used by Parisian saltpetermen ; the crucial tests were of : 1° washed ash mixed with a) mother liquid of raw saltpeter and b) an artificial liquid of « craie de cham
pagne » (chalk cham loin cloth) dissolved in very pure nitric acid; and 2° the same tests using unwashed ash. In the first set of tests, no saltpeter was obtained; the second yielded 7 ounces. Prior to the reports on the tests, Lavoisier had given the results of his analyses of the Parisian ash itself : he had found various salts including « sélénite », « tartre vitriolé » (selenite, “”tartar vitriolated) , Glauber salt and common salt.

At first surprised at the production of saltpeter in the second set of tests with unwashed ash, Lavoisier soon produced more tests and a chemical explanation : «… il ne m’était pas possible de douter qu’il ne se fût opéré unedouble décomposition en vertu d’une double affinité; que, d’une part, l’acide vitriolique qui entre dans la composition de ces sels ne se fût combiné avec la terre calcaire de l’eau-mère pour former de la sélénite, et que, de l’autre, l’acide nitreux ne se fût emparé de la base alcaline du sel de Glauber et du tartre vitriolé pour former de véritable sal pêtre.»  Translate:  “it was not possible for me to doubt that he would have made unedouble decomposition under a dual affinity; that, on the one hand, the corrosiveness acid in the composition of these salts was not combined with the ground limestone mother liquor to form selenite, and, on the other, acid nitrous was not captured the alkali and Glauber’s salt to form tartar Vitriolated real sal Petre”

As confirmation, Lavoisier combined the mother liquids of « very pure » niter with solutions of vitriolated tartar and other vitriolates. In all cases, selenite and a niter of whatever base of the vitriol were formed. He concluded :« // est évident, d’après tout ce qui vient d’être dit, que les cendres qu’on emploie dans la fabrication du salpêtre ne servent pas seulement en raison de la partie alcaline qu’elles contiennent à nu; qu’elles agissent encore en raison de la partie alcaline qu’elles contiennent dans un état de neutralité, et combinée avec l’acide vitriolique. Ainsi, peu importe qu’on emploie, pour décomposer l’eau-mère et pour la convertir en vrai salpêtre, un alcali fixe à nu, ou un sel vitriolique à base d’alcali; l’effet est le même, et l’acide nitreux, dans les deux cas, va chercher de préfé rence l’alcali contenu dans le sel, et en déloge l’acide vitriolique. »  Translated:  Is clear from all that has been said, that the ashes that employed in the production of not only serve saltpetre because they contain the alkaline part exposed; they act yet because of the alkaline part in a state that they contain neutrality, and combined with the vitriolic acid. Thus, regardless of we used to split water mater and to convert it into real saltpeter, alkali fixed bare or vitriolic based salt alkali; effect is the same, and nitrous acid, in each case, pref fetches ence alkali content in salt, and removes the vitriolic acid.”  (Mauskopf, MSH.  1995:  112, 113)

(9) The chemist, Eduard Polenske (1849-1911) (Wikipedia. Pökeln), was born in Ratzebuhr, Neustettin, Pommern, Germany on 27 Aug 1849 to Samuel G Polenski and Rosina Schultz. Eduard Reinhold married Möller. He passed away on 1911 in Berlin, Germany. (Ancestry.  Polenske)  He was working for the German Imperial Health Office when he made the discovery about nitrite in curing brine. (Wikipedia.  Eduard_Polenske)

The Imperial Health Office was established on 16 July 1876 as a focal point for the medical and veterinary in Berlin. First it was the division of the Reich Chancellery and since 1879 the Ministry of the Interior assumed. 1879, the “Law concerning the marketing of food, luxury foods and commodities” was adopted, including the Imperial Health Office was responsible for its monitoring.  Erected in 1900 Reichsgesundheitsrat supported the Imperial Health Office in its tasks.  (Original text:  “1879 wurde das „Gesetz betreffend den Verkehr mit Lebensmitteln, Genußmitteln und Gebrauchsgegenständen“ verabschiedet, für dessen Überwachung unter anderem das Kaiserliche Gesundheitsamt zuständig war.”) (Wikipedia.  Kaiserliches Gesundheitsamt)

Spelling of his surname varies between Polenski and Polenske.

(10)  Dr Ed Polenski’s findings has been published in “Arbeiten aus dem Kaiserlichen Gesundheitsamte , 7. Band, Springer, Berlin 1891, S. 471–474” (

Eben has not been able to get a copy of this document.  The account of the experiment that was done is at best “hear say” and have to be verified.



Cressy, D.  2013.  Saltpeter.  Oxford University Press.

Cressy, D.  Saltpetre, State Security, and Vexation in Early Modern England.  The Ohio State University

Crookes, W.  1868/ 69.The Chemical News and Journal of Physical Science, Volume 3.  W A Townsend & Adams.

Deacon, M;  Rice, T;  Summerhayes, C.  2001. Understanding the Oceans: A Century of Ocean Exploration,   UCL Press.

Dunker, CF and Hankins OG.  October 1951.  A survey of farm curing methods.  Circular 894. US Department of agriculture

Frey, James W.   2009.  The Historian.  The Indian Saltpeter Trade, the Military Revolution and the Rise of Britain as a Global Superpower.   Blackwell Publishing.

Jones, Osman, 1933, Paper, Nitrite in cured meats, F.I.C., Analyst.

Drs. Keeton, J. T.;   Osburn, W. N.;  Hardin, M. D.;  2009.  Nathan S. Bryan3 .  A National Survey of Nitrite/ Nitrate concentration in cured meat products and non-meat foods available in retail.  Nutrition and Food Science Department, Department of Animal Science, Texas A&M, University, College Station, TX 77843; Institute of Molecular Medicine, University of Texas, Houston Health Science Center, Houston, TX 77030.

Kocher, AnnMarie and Loscalzo,  Joseph. 2011.  Nitrite and Nitrate in Human Health and Disease. Springer Science and Business Media LLC.

Lady Avelyn Wexcombe of Great Bedwyn, Barony of Skraeling Althing
(Melanie Reasbeck), Reviving the Use of Saltpetre for Refrigeration: a Period Technique.

Mauskopf, MSH.  1995.  Lavoisier and the improvement of gunpowder production/Lavoisier et l’amélioration de la production de poudre.  Revue d’histoire des sciences

Pegg, BR and Shahidi, F. 2000. Nitrite curing of meat. Food and Nutrition Press, Inc.

Smith, Edward.  1876. Foods. D. Appleton and Company, New York.

Schaus, R; M.D. 1956.  GRIESS’ NITRITE TEST IN DIAGNOSIS OF URINARY INFECTION,    Journal of the American Medical Association.

Twain, Mark.  1876. The Adventures of Tom Sawyer.  Hartford: American Pub. Co.


Figure 1:  From

Figure 2:  From

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Figure 4:   From


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