Krakowski cyrkiel z epoki Galileusza. Archeologiczny dowód nauczania geometrii i astronomii w krakowskim Gimnazjum Akademickim

Dariusz Niemiec

Abstrakt

Cracovian compass of Galileo’s period. Archaeological evidence of teaching geometry and astronomy in Cracovian Academic Gymnasium

In 2007, the priceless collection of historic scientific instruments stored in Jagiellonian University Collegium Maius was enriched with a unique scholar compass, a sensational archaeological discovery made in the Cracow university quarter. The above-mentioned brass compasses, with a signature in the form of the Greek letter Ω, was found in 2005 in Cracow, in the northern courtyard of Jagiellonian University Collegium Novum. In the context of the discovery, the compasses can be related to the building, the remains of which were uncovered in the western part of the Collegium Novum courtyard. From 1589 to 1643, this building housed the oldest academic gymnasium, which is the so-called Classes, renamed as Nowodworski School after 1625. After the location of the secondary school was changed in 1643, the building was still called Old Classes until 1813, although it had not belonged to the university since 1783. The afore-mentioned secondary school, established near the Cracow Academy from 1586 to 1588, following the example of the then progressive solutions known from the University of Heidelberg, served as a so-called academic pedagogium; that is, a school preparing young people for more serious university studies. The described geometric instrument was dug up from a depth of 450 cm, within the area of a black stratum of ashes, interpreted as a usable level of the basement floor of the late Renaissance building of the academic gymnasium. It is worth mentioning that in the same usable stratum, apart from the compasses, some fragments of ceramic vessels and tiles, the technological features of which are typical for early modern ceramics, dated to the end of the 16th century, were discovered too. The determination of the origin date of the compasses is partly enabled by a numismatic item coming from the stratum that was lower, and thereby older, than the stratum of ashes. It is an old ‘rechen pfenning’, minted during the last twenty years of the 15th century. On this basis, taking into consideration not only the moment of minting, but also a certain period of using the pfennig in trade before it had been lost, it could be assumed that the stratum in which the compasses were found had been formed not later that in the mid-16th century.

The compasses discovered in Jagiellonian University Collegium Novum are made of brass and consists of two not very long legs with not very sharp ends. The hinge joining the two main parts of the compass was made as a multi-spherical handle. This part of the compasses is polygonally shaped in the cross section, and additionally, it is separated from the narrowed handle by another part in the form of a convex, horizontal slat. At two-thirds of their height, both legs of the instrument are ornamented with two horizontal grooves cut along the whole perimeter. On the side of one of the compasses’ legs, just below this ornamentation, there is a signature in the form a concave Greek letter omega, very carefully struck with a die. Typologically, these compasses can be classified as so-called bow compasses, used to measure distances. They cannot be regarded as a precise scientific instrument because of both the too short legs and their blunt ends, with no distinct spikes – thus they could not be used to make precise measurements. They were used rather as a school instrument. In the Cracovian academic gymnasium, the compasses could serve the future students as a device for learning geometry.

With regard to the above, it is worth mentioning that at the turn of the 16th century, geometry and astronomy were taught in this school by two outstanding university professors, who later became Cracow Academy vice-chancellors – Walenty Fontana and Jan Brożek. Jan Brożek’s direct indulgence was founding an individual scholarship for a student specialising in geometry, and the creation of a permanent fund for the purchase of the newest works on mathematics and astronomy, as well as new astronomic and geometric instruments. In an antique book originally belonging to this scientist, there is still a handwritten note concerning the purchase of a whole set of measuring instruments, including compasses, from the Padua house belonging to the famous Galileo. There is no sufficient evidence to establish for certain that the Cracovian compass comes from Galileo’s workshop, but it is certain that it is of Galileo’s period. Apart from the previously mentioned written sources, the fact that it was most probably imported from this area of contemporary Italy is proved by the quality of the material it is made of and the excellent precision of finishing the details of the brass instrument. On the basis of archaeological evidence, it can be proved that the compass found in Collegium Novum was used and finally lost at the turn of the 16th century. Such a proposition of dating the mentioned find is additionally confirmed by the analysis of the iconography of the Portrait of Johannes Kepler, from 1610, from Prague; a work by an anonymous painter, on which compasses with the same stylistic features as the Cracovian instrument, including an almost identical shape of the handle knob, was presented as the attribute of the famous German astronomer. The compasses can be dated to the end of the 16th century at the earliest, first of all because it has been signed with a workshop mark, as the custom of placing the maker’s signature on the European scientific instruments became widespread during the late Renaissance period, a good example of which can be a set of compasses signed with the initials of Humfrey Col and made in 1575 in his London workshop. The discovery made on the premises of the oldest in Europe gymnasium pedagogium in Rostock (so called Porta Coeli), where compasses from the second half of the 16th century had been submerges in a latrine, was of the importance analogous to the find made in Cracow university quarter. Both measuring instruments – from Cracow and from Rostock – are meaningful evidence of the high level of the teaching of geometry and astronomy in secondary schools, established at that time as institutions of outstanding academic centres. A fragment of a scene with so-called Athenian School, which is a part of the famous frescos painted by Rafael Santi from 1509 to 1513 in Vatican Stanza della Segnatura, is more crucial evidence that such a type of compasses was used during Renaissance as teaching devices. The mentioned frescos show Euclid, who explains the rules of his geometry to a group of scientists using bow compasses, held in his hand, to engrave geometric figures and constructions on a wax tablet.

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