ABSTRACT:

Among the cross pennies of later types, contained in the hoard from Słuszków near Kalisz and dated to after 1105, there are 73 obols — coins worth half a penny. The coins from the Słuszków hoard are dated to the period from the second half of the 11th century to the beginning of the 12th century. The assemblage is dominated by specimens with the image of a beaded cross and individual coins featuring a simple cross, a crosier as well as a crosier, a ring and a banner — types V, VI, VII and VIII according to M. Gumowski’s typology. Most probably, all the obols were struck by bishop’s mints in the archdiocese of Magdeburg.

SUMMARY:

In the early Middle Ages, the smallest denomination of coins used across Latin Europe was the obol. The most frequent finds of the coin, dated to the second half of the 10th century and the beginning of the 11th century come mainly from Germany, Bohemia and Hungary. The high silver content of the pennies at the time necessitated the production of smaller denominations, used for concluding small trade transactions, particularly in the countries where the coins’ origin. In the Polish lands small transactions involved predominantly fragments of coins, which constituted the dominant part of the hoard material from the times of Mieszko I and Boleslaus I the Brave. The debasement of pennies throughout the 11th century resulted in both obols and coin fragments disappearing from hoards. Almost of all of the late cross pennies CNP 813 and 867–869 from the Słuszków hoard, dated to the end of the 11th century and the beginning of the 12th century were not divided. The coins produced for the longest period of time (until the beginning of the 12th century) discovered in the Polish lands were cross obols. The largest collection of the coins comes from the hoard discovered in Słuszków near Kalisz and dated to after 1105. The assemblage contains 13061 coins, mainly early variants of cross pennies from the end of the 11th and the beginning of the 12th century.

Due to the lack of some types of cross obols in the most complete classification of the cross coins in Marian Gumowski’s Corpus Nummorum Poloniae, the typology based on the obols from the Słuszków hoard is presented.

The earliest variant, SoV-1, similar to CNP 674, has on its obverse the older version of the beaded cross (beads along the quadrangle). In all certainty, it is dated to before the half of the 11th century. Chronologically, the second type of obol in the Słuszków assemblage is the SoV-2 variant, not recorded in CNP. The artefact relates to a group of cross pennies from the so-called transitional group with a beaded cross, where some signs were arranged along the quadrangle and some along a circle. It may be dated to the half of the 11th century. The next five variants of cross obols, SoV-3 — SoV-7, are similar to CNP 677, their margins are wide enough for the legend to be legible. The obverse features the younger beaded cross, most often with 12 beads. The coins were minted in the third quarter of the 11th century. The next group of obols comprises variants SoV-8 — Sov-16, characterised by relatively narrow margins, which translates into only partial legibility of the characters. On the obverse there is the younger beaded cross. The obols may be dated back to the turn of the 4th quarter of the 11th century. The youngest group of cross obols from Słuszków are coins classified as variants SoV-17 — SoV-21. On the obverse they have a beaded cross with eight or nine beads. They may be dated to the last quarter of the 11th century. There are two more obols that may be identified as cross obols with beaded crosses, classified as variants SoVA-1 and SoVA-2. The specimens feature a beaded cross whose two arms are represented as prolonged triangles, similarly to the crossing of the crosier on the younger variants of type VII cross obols. In all probability, the coins may be dated to the turn of the 4th quarter of the 11th century. In the Słuszków hoard, the type VI cross obols with the simple cross are represented by one specimen of the SoVI-1 variant (CNP 876), dated probably to the last two decades of the 11th century.

The Słuszków hoard contains only one type VII obol — SoVII-1. The coin shows a short, crossed crosier, to the left, with a narrow crook, ending with a large dot. The coin may be dated to the last quarter of the 11th century. The last and probably the youngest group of obols comprises type VIII specimens of the SoVIII-1 type (CNP 1029). Obols of this type are known mostly from the Polabian region and can be dated to the end of the 11th and the beginning of the 12th century. In all certainty, all the cross obols from the Słuszków hoard were struck in Saxony, in mints of Magdeburg, Halle-Giebichenstein, Merseburg, Naumburg and perhaps Meissen, a fact confirmed by the artefacts discovered in Polabia. The large number of the coins known from Greater Poland — the region of Poland lying closest to Magdeburg, testifies to the Saxon origin of the cross obols from the end of the 11th and the beginning of the 12th century.

Eight coins (seven medieval and one modern) were found during archaeological rescue excavation on the Main Market Square in Kalisz in 2012. Four coins (including one fragment) are hohlpfennigs, probably all of them are of Polish origin (from Greater Poland?) and date from the thirteenth-fourteenth century. The next three are: a halved penny, perhaps from the end of the thirteenth century, West Pomeranian penny and, probably, a Silesian heller from the fourteenth-fifteenth century. The modern coin is a heavily worn copper shilling by John Casimir (1648–1668).

The aim of the study is to identify the relevant aspects of numerical analysis of impact of projectiles with soft cores into a package composed of thin flexible plies located on the plastic backing. In order to illustrate the problem, normal impact of 7.62 mm TT projectile into an unclamped package comprising 36 plies of Dyneema SB71 supported on the plastic backing was selected. The problem was solved with the use of the finite element method (FEM) with the explicit integration scheme (central difference method) of motion equations in the matrix form. Based on the conducted numerical computations, it was revealed that obtaining the extreme deformations of a projectile soft core and the backing material in Lagrangian description requires employment of adaptive methods. The proposed R-adaptive method performs its role but must be used carefully due to the mass loss which may appear during calculations.

Hydraulic fracturing of rocks boosts the production rate by increasing the fracture-face surface area through the use of a pressurized liquid. Complex stress distribution and magnitude are the main factors that hinder the use of information gathered from in situ hydraulic fracturing in other locations. Laboratory tests are a good method for precisely determining the characteristics of these processes. One of the most important parameters is breakdown pressure, defined as the wellbore pressure necessary to induce a hydraulic fracture. Therefore, the main purpose of this investigation is to verify fracture resistance of rock samples fractured with the assistance of the most popular industry fluids. The experiments were carried out using a stand designed specifically for laboratory hydraulic fracturing. Repeatable results with a relative error within the range of 6-11% prove that the experimental methodology was correct. Moreover, the obtained results show that fracturing pressure depends significantly on fluid type. In the case of a water test, the fracturing pressure was 7.1±0.4 MPa. A similar result was achieved for slickwater, 7.5±0.7 MPa; however, a much lower value (4.7±0.5 MPa) was registered in the case of carbon dioxide.

Archaeological excavations conducted recently in Kalisz brought about two groups of Jagiellonian pennies. One is a small hoard of less than twenty coins of Vladislaus Jagiełło, found near the St. Joseph Sanctuary. The other comprises 37 coins found separately in archaeological excavations at early mediaeval settlement known as Stare Miasto (Old Town), adjacent to the hillfort at Zawodzie.