In the Middle Ages, alchemists were known for their secrecy and did not share their knowledge with others. Among them, the Danish Tycho Brahe was no exception. Therefore, we do not have accurate information about what he did in his alchemical laboratory located beneath his residence and observatory Uraniborg on the island of Ven.

Only a few of his alchemical recipes have been preserved, and today the remnants of his laboratory are extremely rare. Uraniborg was demolished after his death in 1601, and the building material was scattered for reuse.

However, during excavations from 1988 to 1990, fragments of ceramics and glass were found in the old garden of Uraniborg. It is believed that these fragments come from the basement alchemical laboratory. Five of these fragments—four glass and one ceramic—were subjected to chemical analyses to determine which elements the original glass and ceramic containers came into contact with.

The chemical analyses were conducted by Professor Emeritus and archaeometry expert Kaare Lund Rasmussen from the Department of Physics, Chemistry, and Pharmacy. Senior researcher and museum curator Poul Grinder-Hansen from the National Museum supervised the insertion of the analyses into the historical context.

Elevated levels of trace elements were found on four fragments, while one glass fragment did not show specific enrichments. The study was published in the journal Heritage Science.

Elements in the alchemical laboratory

- The most intriguing elements were found in higher concentrations than expected—which indicates enrichment and provides insight into the substances used in Tycho Brahe's alchemical laboratory, said Kaare Lund Rasmussen.

The enriched elements are nickel, copper, zinc, tin, antimony, tungsten, gold, mercury, and lead, and were found either on the inside or outside of the fragments.

Most of them are not surprising for an alchemist's laboratory. Gold and mercury were—at least among the higher social strata—known and used against a wide range of diseases.

Mysterious tungsten

- But tungsten is very mysterious. Tungsten was not even described at that time, so what can we conclude from its presence on a fragment from Tycho Brahe's alchemical laboratory? asked Kaare Lund Rasmussen.

Tungsten was first described and produced in pure form more than 180 years later, by the Swedish chemist Carl Wilhelm Scheele. Tungsten occurs naturally in certain minerals, and perhaps the element found its way to Tycho Brahe's laboratory through one of these minerals. In the laboratory, the mineral may have undergone some processing that separated the tungsten, without Tycho Brahe being aware of it.

However, there is another possibility that Kaare Lund Rasmussen emphasizes there is no evidence for—but which could be plausible.

As early as the first half of the 1500s, the German mineralogist Georgius Agricola described something unusual in tin ore from Saxony, which caused problems when trying to smelt the tin. Agricola called this strange substance in tin ore "Wolfram" (German for wolf foam, later renamed tungsten in English).

Medicine for plague, syphilis, and stomach pains

- Maybe Tycho Brahe heard about this and thus knew about the existence of tungsten. But that is not something we know or can say based on the analyses I conducted. It is only a possible theoretical explanation for why we find tungsten in the samples, said Kaare Lund Rasmussen.

Tycho Brahe belonged to the branch of alchemists who, inspired by the German physician Paracelsus, tried to develop medicines for various diseases of that time: plague, syphilis, leprosy, fever, stomach pains, etc. But he distanced himself from the branch that tried to create gold from less valuable minerals and metals.

In line with other medical alchemists of that time, he kept his recipes secret and shared them only with a few selected individuals, such as his patron, Emperor Rudolf II, who allegedly received Tycho Brahe's recipes for a plague remedy.

We know that Tycho Brahe's plague remedy was complicated to produce. It contained theriac, which was one of the standard medicines for almost everything at the time and could have up to 60 ingredients, including snake meat and opium. It also contained copper or iron vitriol (sulfates), various oils, and herbs.

After various filtrations and distillations, the first of three Brahe's plague recipes was obtained. This could be made even stronger by adding tinctures, for example, of coral, sapphire, hyacinth, or potable gold.

The connection between astronomy and alchemy

- It may seem strange that Tycho Brahe dealt with both astronomy and alchemy, but when you understand his worldview, it makes sense. He believed that there were clear connections between celestial bodies, earthly substances, and body organs. Thus, the Sun, gold, and the heart were connected, as were the Moon, silver, and the brain; Jupiter, tin, and the liver; Venus, copper, and the kidneys; Saturn, lead, and the spleen; Mars, iron, and the gallbladder; and Mercury, mercury, and the lungs. Minerals and gems could also be connected to this system, so emeralds, for example, belonged to Mercury, explained Poul Grinder-Hansen.

Kaare Lund Rasmussen previously analyzed Tycho Brahe's hair and bones and found, among other elements, gold. This could indicate that Tycho Brahe himself took medicines that contained potable gold.

Brahe's alchemical laboratory was equipped with sixteen furnaces, which allowed various distillations and purifications. This laboratory was located in the basement to facilitate fuel deliveries needed for the furnaces' operation, without disrupting the work of the astronomical observatory. It even had a winter kitchen with an additional five furnaces that allowed for faster processes.

Tycho Brahe kept his alchemical works secret, sharing them only with a few selected individuals, such as his sister Sophie Brahe, who also experimented in his laboratory. His works were focused on practical and useful results, not on creating gold.

Source: Syddansk Universitet