Mercury. It is not often found in archaeological investigations. Yet this drop of mercury is one of the 33,000 finds in the National Ship Archaeological Depot.
The drop comes from the shipwreck Approach Molengat, a wreck that is currently being investigated as part of the NWO Odyssey project Wreck Approach Molengat. Analysis and presentation of the first underwater excavation in the North Sea. Many semi-finished products have been found in this shipwreck, including wrought iron bars, blocks of lead, tin rolls, packages with cowhides, pieces of textile, ivory, but also finished products such as boxes with cannonballs, lead musket balls, pins, and therefore also mercury. Mercury is the only metal that is liquid (it only solidifies at -38.87 degrees Celsius), also under water! During the excavation of Aanloop Molengat, the diving archaeologists regularly encountered drops of mercury on the seabed, rolling back and forth in the current. A few drops were recovered during the investigation.
Transport of mercury in the seventeenth century
Mercury is a heavy metal and difficult to transport. Experiments were carried out in the seventeenth century with the storage and transport of mercury in pig bladders, glass bottles and stoneware jars. No stoneware shards were found in Aanloop Molengat, but lead caps from glass bottles were found. The caps were measured with a handheld XRF by Bertil van Os, senior researcher inorganic materials at the RCE, to determine whether an increased amount of mercury is present. An XRF measures the exact composition of objects. The measurements show that no mercury is present in and on the lead caps, but there is in the neck or collar of the glass residue in the cap. We can cautiously conclude that the mercury was transported in glass vials with these lead caps. So it was not the fishing Latin of the old Texel fisherman who, while enjoying a beer in the harbor, told me that many years ago he fished up glass tubes near the 'mercury wreck', filled with mercury and wrapped with rope!
'As mad as a hatter'
Mercury was used in the 17th century, among other things, in thermometers and barometers, in the making of mirrors and for medicinal purposes, such as the treatment of syphilis. The mercury (mercury in English) gave rise to the pun in this last application:"A night in the arms of Venus leads to a life on Mercury." For 'healing', the mercury had to be taken by mouth, rubbed on the skin or injected.
Mercury was also used in making felt hats. Animal skins were placed in a bath of mercury-nitrate, which softened the stiff hairs. The hatters had the reputation of drunkards:they trembled, spoke with tongues, and had mood swings. However, it was all caused by the inhaled mercury vapor, which caused irreparable damage to the brain, nervous system, liver and kidneys. In England, the expression 'as mad as a hatter' arose, in the Netherlands it was called the 'hatmaker's disease'.
The wreckage and the documentation of the research are located in the National Ship Archaeological Depot of the Cultural Heritage Agency of the Netherlands.