Ajalooline 1560. aastast pärinev Kölni kaal Tartu Ülikooli ajaloo muuseumis
Historically valuable scales (dated 1560) from Cologne at the History Museum of the University of Tartu
Tullio Ilomets, cand.chem., History Museum of the University of Tartu
The oldest of all the precision measurement instruments preserved at the History Museum of the University of Tartu is probably the complete set of coin scales manufactured in Cologne in 1560. It comprises the scales box (12.5 x 22.0 x 2.7 cm), the scales and the weights: 28 tetragonous brass weights, two S-shaped copper-wire weights and one semi-circular copper weight.
The scales were donated to the museum by the university’s Chair of Inorganic Chemistry in 1982. The chair staff believed that the scales had belonged to Ferdinand Giesele, Professor of Chemistry and Pharmaceutics (1781-1821, served at the university from 1814-1821). No other information about the original ownership of the scales or other aspects of their long existence is available.
The inside of the scales box lid contains an inscription telling us that a master by the name of Thomas Wulmar Hussen made the scales on St. Johan Street in Cologne in 1560. This particular set is different from most coin scales manufactured in Cologne because of the way it is suspended on the brass rod inserted into the lid. Both scalepans are round and the whole front part of the scales is covered with a flowery metal ornament. Another notable difference lies in the fact that the 31 weights are of very small mass and are stored not in special recesses in the scales box but mostly in paper envelopes with explanatory inscriptions. The scales box in fact has two compartments with lids and two open drawers for weight storage.
The main objective of this article is to describe the set in detail. The scales and scales box were thoroughly measured. The weights were weighed on Mettler B 6 analytical semi-micro scales.
The author attempts to determine the weight system to which those of this particular set of scales belong. For the purpose of this analysis the mass value of the Cologne mark was set to 233.8123 g.
The calculations performed indicate the following: it is most likely that 15 of the weights belong to the Dutch troy-pound (as) system (weights 5-18 and 31); that two of the weights belong to the English troy-pound (grain) system (weights 25 and 26); that six of the weights belong to the ordinary carat weights system (weights 1, 2, 19, 20, 21, 24); that four of the weights belong to the Cologne mark’s penny (Richtpfennig) system (weights 3, 4, 29, 30); that three of the weights belong to the Nuremburg pound (Pfund) system (weights 22, 27, 28); and that one further weight (23) was denoted as a heller.
The article contains a brief overview of the Cologne coin scales manufacturing process, the coin-making industry and the history of the Cologne mark. The author also examines issues associated with the process of determining the initial mass value of the Cologne mark based on old and new reference sources.
This exhaustive description allows readers to draw the conclusion that this is a very rare reference-standard set of scales.