A treatise on chemistry By Christophe Glaser 1663

A treatise on chemistry  By Christophe Glaser 1663 

The purification of gold by antimony.

The best purification of gold is that which is done by antimony; for lead only carries imperfect metals, and weary of silver with gold: cement often leaves impure gold, and eats a portion of it: the inquart is not always a definite proof of purity of gold; for sometimes it happens that gold having been mixed with some sulphurous matters, their odor envelops some portion of silver, which was added to the gold to inquire it: which portion falls into precipitates with the gold by the departure, and gives surprising and short joys, half wise, to which it happens believing to have found the means to increase the gold, but when one examines the whole with funds, they are found far from their expectations. We can be sure that the gold that has passed through the antimony, is perfectly purged & delivered from any mixture, because only gold can resist this devouring Wolf. 

Take, therefore, an ounce of gold, such as the goldsmiths use, put it in a crucible between the coals, in a furnace, and when it is very red, it is necessary to gradually put four ounces of good antimony powder, which will melt immediately, and at the same time devour the gold, which otherwise is of a very difficult fusion, because of its very perfect composition: when all is melted like water, and the material is sparking, it is a mark of the action that antimony has made to destroy the impurities of gold, which is why it must be left a little longer on the fire, then throw it promptly into a horn of iron, which has been previously heated and greased with a little oil, and when the material is poured into it, it is necessary at the same time to strike with the tweezers on the cornet to bring the regulate down to the bottom: & after the material is a little cooled, it is necessary to separate the slag, and then weigh it, put it to melt in a rather large crucible, and gradually add double its weight of saltpetre, then cover the crucible, so that the coal can not enter, & giving a fire alive, saltpeter consumes all that may have remained of the antimony with the gold, and the gold is put in the bottom in very beautiful and pure base, and one can throw it all hot in a corner, or let it cool in the crucible, which must be broken afterwards to separate the pellet from the salts. 

This method of purifying the golden rule is not common and ordinary, but it is preferable because it is done more quickly, but it is practiced only in small quantities; the common way is done by putting a flat crucible on the melting fire, and in the crucible the golden regulator, and blowing continuously, until the antimonial part is exhaled, it takes not only time, but to be exposed to the harmful exhalations of antimony, which it is always good to avoid.

In 1663, Christophe Glaser (1628-1678) published a treatise on chemistry that will have about forty editions. It indicates the preparation of salts known as "Glaser salts", there is salt eye (potassium nitrate) and polychreste salt (potassium sulfate), it describes the operations with care and takes care of little theory, finally it mentions only one chemist Jean-Baptiste Van Helmont (1580-1644), the discoverer of the existence of gases. He distinguishes the active principles: mercury, sulfur, salt and passive principles: phlegm and earth. Antoine Vallot (1594? -1671), first doctor of King Louis XIV, made him the post of demonstrator in the Garden of the King (Jardin des Plantes) after the departure of Nicaise Le Febvre (1610? -1669). Nicolas Lemery (1645-1715) was one of his students. He must flee France in 1672, following the poison case.