Lemery presents the common salt Spirits preparation. Basilius Valentinus often recommends the common salt, defining it a wonderful balsam to open matter.
What I want to point at here are not only the operations per se, even if they are important and peculiar not only for the iatro-chemists but for everyone running vessels in that period, but also at the matters used by Lemery. The following combinations may indeed seem rather physical than chemical. At least in comparison to what we nowadays intend as chemistry: the science of matter purity. But, as we know, the purity of matter doesn’t lead to our Mercurius Philosophorum.
The spirits mentioned by Lemery may be recognized as containing the acid of common salt, or hydrochloric acid, since the french chemist puts on display a very difficult distillation process with the presence of rain water. A kind of distillation even more than difficult, quite impossible indeed, is the one without any addition attributed to monsieur Seignette. This miraculous dry extraction of gas hydrogen chloride is performed by Seignette up to nine times from the same matter. Not so far from the seven to nine reiterated salts volatilizations needed to extract Secret Fire/Mercurius. In fact a spirit, chemical or alchemical, is the final product of a series of distillations. But is at the end of Lemery’s description that the introduction of wine and spirit of wine, so common in ancient chemistry, may seem so close with some methods of salts volatilization made by means of alcoholic substances. A method not neglected by alchemists. Definitely an interesting reading.
My translation from original french. Nicolas Lemery, Cours de la Chimie, Paris 1675 (an introduction for this book can be found at Lemery & Aqua Regia First Step, Sal Armoniac) :
“ON COMMON SALT: There are three kinds of common salt: the fossil salt, the fountain salt and the sea salt; the first one is called rock salt, for it is shining and clean like a gem, which we can find entire mountains in Poland, and somewhere else, filled with this salt. The second one is obtained from some fountain waters evaporation and the last one is obtained by sea water crystallization after its humidity evaporation. These three salts are of the same nature and produce a simile effect. They are not used only as food but sometimes also as medicine, when for example one wants to turn them into strong carminatives.
It is to point out that the rock salt is just a bit more penetrating than the sea salt retreating by crystallization and that the sea salt retreating by crystallization is more penetrating than that one made from evaporation of the contained waters.
The reason causing the rock salt to be formed is because it has never been dissolved in water and consequently it has not lost any of its points (point in original french) while the other kinds of common salts tend to miss the most subtle parts into the water, mainly when this is greatly rough such as sea waters.
The sea salt made in Normandy, by sea water evaporation on fire, is less strong than that one processed in Rochelle by crystallization, because during evaporation the salt most subtle parts have been evaporated and this is evidenced when distilling the sea water at whatever degree of fire: it will be always able to raise some volatile salt with it, which will make the evaporating sea water unable to remain saltless, and this from experience.
The crystallized sea salt cannot be achieved in the same way, since it freezes by itself when the sea waters rested some time in places that have been set to receive them.
I thoroughly described my concept concerning the origin of these three forms of salt in the notes I made on Principles, so it will be useless to repeat it again. ( Cours de la chimie page 13: ……I could say that the sea and fountain waters have taken their salinity from the rock salt they have encounter and dissolved). In order to be purified the salt should be melted in water: the dissolution has to be filtered through a grey paper, then all the humidity has to be evaporated in a bowl, the remaining will be a very white salt.
COMMON SALT CALCINATION: take a bowl without any enamel applied and get it hot red, throw inside one ounce of sea salt and then cover it: the salt will crackle and reduce in powder. This cracking noise is called decrepitation. When it will stop you will put salt into the pot again and keep on like that till you will have enough. The pot must be hot red all the time. When it will not crackle anymore, you will put it into a well stoppered bottle to prevent humidity from entering.
NOTES: When the cracking salt is being put into the fire it release its inner humidity which, feeling scarce, pushes impetuously and finding too much closed pores exerts force to make its way. In fact all the things which have too much closed pores make such a noise when calcinating, like glass and shells.
When one wants to use again the decrepitated salt, it is good to get it calcinated anew, because the air humidity will add again what fire has already discharged. When this salt is deprived of humidity it will be better absorbed as a transpirating medicine. A bit of Salt Tartar will improve it.
SPIRIT OF SALT: Dry some salt on a little fire or under the sun, then reduce two pounds in a subtle powder, mix it exactly with six pounds of clay or powdery bole. Make from this mixture a solid paste with the necessary quantity of rain water, then make out of it some nut size pellets which must be exposed under the sun, and when they will be completely dry, put them in a clay or glass horn, provide it will be well closed, and must be empty for a third, place the horn on reverberation fire and fit a recipient or ball on it without luting the joints. At start give a very light fire to heat the horn and to let out drop by drop an insipid water; when you will see some white vapors following these drops, throw what it will be in the recipient and having it well closed, exactly lute the joints. Increase the fire little by little till the ultimate violence. And keep on the condition for about fifteen hours, in the meanwhile the ball will heat and filled with white clouds. But by the time it will cool down, those white clouds will disappear and the operation will be finally achieved. Then free the joints from luting and you will find the Spirit of salt in the recipient. Pour it in a clay or glass well wax stoppered bottle. This Spirit is aperitif (1) and used till a pleasant acidity into juleps for those subjected to kidney stones. If diluted in a little water it is also emploied to clean teeth and eat the bones issue.