The famous astronomer Johannes Kepler (1571-1630) appears to have practiced alchemy, according to an article in the journal Talanta. On the pages of one of his manuscripts, Hipparchus, written in the 1620s, scientists have found traces of silver, gold and arsenic, mercury and lead salts.
In the XVI-XVII centuries, one of the trends of alchemy was transmutation - the transformation of some metals into others (in particular, "base" lead into "noble" gold). Some European monarchs patronized alchemists, hoping to get from them the philosopher's stone, which turns other metals into gold. Among them was the Danish king, who gave his astronomer, astrologer and alchemist Tycho Brahe (1546-1601) an island, on which he set up an observatory and a laboratory for carrying out alchemical experiments. In 1599, Brahe was forced to leave the country and moved to Prague, where he continued to study astronomy and alchemy. In 1600, Kepler came to Prague, and for the last 11 months of Brahe's life, both scientists worked together. Perhaps, at the suggestion of Brahe, Kepler was carried away by alchemical experiments,although in written sources this interest is not mentioned and there is no direct evidence that the scientist carried them out.
Israeli and Italian chemists, led by Pier Giorgio Righetti of the Technical University of Milan, analyzed one of Kepler's manuscripts and found traces of metals and their salts on its pages, indicating that Kepler may have practiced alchemy. Researchers have previously developed a method for collecting proteins and low molecular weight chemical compounds from fragile artifacts, such as pages of old books or fragments of textiles. They proposed to collect compounds using a carrier film coated with synthetic polymers, to which the substances of interest to researchers “adhered” due to ionic or hydrophobic interactions.
In their new work, the scientists used a film coated with chelating agents, substances that can bind to metal ions. After exposure, it was analyzed using inductively coupled plasma mass spectrometry, secondary ion mass spectrometry, and photoelectron spectroscopy. In this way, scientists analyzed Kepler's manuscript "Hipparchus", which he prepared for over 15 years, from 1603-1604 to 1620. Now it is kept in St. Petersburg, in the archives of the Russian Academy of Sciences. The researchers analyzed 20 pages of the manuscript and found traces of gold, silver and arsenic, complexes of gold with mercury, and lead salts on all of them. Several pages contain traces of cinnabar, mercury (II) sulfide. The amount of metals exceeded the background values from three (gold) to 90 times (arsenic).
Metal content in Kepler's manuscript pages and background values.
The authors suggested that Kepler was engaged in alchemy while working on the manuscript. Metals and their compounds could fall on the paper from the scientist's fingers and sleeves. It is also likely that the scientist used mercury sulfide, which was not found on all pages, not in alchemical experiments, but as a red paint. Scientists note that the scientist's manuscripts may become the only proof of his studies in alchemy. It is not possible to check Kepler's remains for the presence of metals, as was done with the body of Tycho Brahe. A year after the death of the scientist, his grave was plundered by the Landsknechts and the remains were lost.
Ekaterina Rusakova