15. The spagyrical Pharmacopœia, or Dispensatory.--In this book he treats chiefly of medicines peculiarly his own; one of those, on which he bestows the greatest praise, is _secret sal ammoniac_, or sulphate of ammonia. He describes the method of preparing this salt, by saturating sulphuric acid with ammonia. He informs us that it was much employed by Paracelsus and Van Helmont, who distinguished it by the name of _alkahest_. 13. Book of Fires.--Full of enigmas. 14. Treatise of the three Principles of Metals; viz. sulphur, mercury, and salt of philosophers; how they may be profitably used in medicine, alchymy, and other arts. 15. A short Book of Dialogues. Chiefly relating to alchymy. 16. Proserpine, or the Goddess of Riches. 17. Of Elias the Artist. 18. Of the three most noble Stones generated by three Fires. 19. Of the Purgatory of Philosophers. 20. Of the secret Fire of Philosophers. 21. A Treatise concerning the Animal Stone. John Kunkel, who acquired a high reputation as a chemist, was born in the Duchy of Sleswick; in the year 1630: his father was a trading chemist, or apothecary; and Kunkel himself had, in his younger years, paid great attention to the business of an apothecary: he had also diligently studied the different processes of glass-making; and had paid particular attention to the assaying of metals. In the year 1659, he was chamberlain, chemist, and superintendent of apothecaries to the dukes Francis Charles and Julius Henry, of Lauenburg. While in this situation, he examined many pretended transmutations of metals, and undertook other researches of importance. From this situation he was invited, by John George II., Elector of Saxony, on the recommendation of Dr. Langelott and Counsellor Vogt, as chamberlain and superintendent of the elector’s laboratory, with a considerable salary. From this situation he went to Berlin, where he was chemist to the elector Frederick William; after whose death, his laboratory and glass-house were accidentally burnt. From Berlin he was invited to Stockholm by Charles XI., King of Sweden, who gave him the title of counsellor of metals, and raised him to the rank of a nobleman: here he died, in 1702, in the seventy-second year of his age. Kunkel’s greatest discovery was, the method of extracting phosphorus from urine. This curious substance had been originally discovered by Brandt, a chemist, of Hamburg, in the year 1669, as he was attempting to extract from human urine a liquid capable of converting silver into gold. He showed a specimen of it to Kunkel, with whom he was acquainted: Kunkel mentioned the fact as a piece of news to one Kraft, a friend of his in Dresden, where he then resided: Kraft immediately repaired to Hamburg, and purchased the secret from Brandt for 200 rix-dollars, doubtless exacting from him, at the same time, a promise not to reveal it to any other person. Soon after, he exhibited the phosphorus publicly