Radoszyce forests · a supply model, not a recipe

Glassworks in the Holy Cross forests

Forest glass needed three things: sand, a flux (potash) and fire. The forest supplied two of them at once, but in two different ways: wood burned in the furnace, and its ash became potash. Cut off the forest and see what really stops working.

Diagram: a shard of forest glass and three supply routes On the right is an irregular shard of glass. Three horizontal bands run through it: sand at the top, fuel in the middle, potash at the bottom. On the left the forest splits into two wood lanes: one leads to the fuel band, the other, via the potash works, to the potash band. A missing band is drawn with a dashed line and a red cross, and glass without a full set of ingredients is grey and hatched. This is our own illustration, not a photograph of a find and not a map.
Our own diagram, a qualitative model. The irregular shape is an illustration of glass, not a photograph or a find from the Radoszyce forests. The bands are supply routes, not a scale and not a map. A missing band: a dashed line with a cross.
  • Sand
  • Forest (felling)
  • Fuel: wood lane 1
  • Potash works: ash turned into potash
  • Potash: wood lane 2
  • Delivery or purchase from outside
  • Missing

Model result

Melting possible in the model

The batch has sand, potash and fuel, so in the model the glass melts.

Colour in the model: greenish (iron in the sand).

Cut off a source, see the effect

Each column is one band of the drawing. A choice changes the diagram above, the model result (repeated in the sticky bar below) and the description in the same column. Wood appears twice: as fuel (lane 1) and as ash for potash (lane 2), and each lane has its own source.

Model resultMelting possible in the model.

Band 1 · silica

Quartz sand

present

Present: local sand. The iron in it tints the glass greenish.

Source of both wood lanes

Forest: own felling

ongoing

The forest supplies wood for both lanes at once: as fuel and as ash.

Band 2 · lane 1 · wood as fuel

Furnace fuel

present

Fuel present: wood from own felling.

Band 3 · lane 2 · wood as ash

Potash (flux)

present

Potash present: ash from own felling, processed at the potash works.

Two wood lanes, two separate effects

Suspended felling is not a single off switch for the glassworks. It stops the lanes that draw on the forest; outside supplies rescue each of them separately. Below are six cases side by side, worked out with the same rules as the diagram. The sand is local unless stated otherwise.

Comparison of model cases. “Show in model” sets the diagram to the chosen case.
CaseFuel (lane 1)Potash (lane 2)SandMelting in the modelAction
Self-sufficient glassworks presentfrom the forest presentash from the forest present possible
Forest cut off, no supplies missingfelling suspended missingno ash present haltedtwo separate shortfalls
Forest cut off, fuel delivered presentdelivered missingno ash present haltedno potash
Forest cut off, potash purchased missingfelling suspended presentpurchased present haltedno fuel
Forest cut off, fuel delivered and potash purchased presentdelivered presentpurchased present possible
Forest ongoing, no sand presentfrom the forest presentash from the forest missing haltedno sand

What this model says and what it does not

The model answers one question: which supply routes are continuous and which are broken. It gives no recipe and no numbers.

Model assumptions

  • The result is “present” or “missing”. There are no temperatures, batch proportions, quantities of wood or forest areas.
  • Wood has two roles: fuel burned in the furnace and ash from which potash is made.
  • Without potash the batch will not melt. This is a model assumption: the flux lowers the temperature at which silica fuses (Corning: Flux, to be verified).
  • The greenish colour here comes from iron in the sand. This is one possible cause, and colour is not enough to attribute a recipe. “Washed” sand with less iron is a model assumption, not information about this glassworks.
  • Left out: glass stabilisers, the construction of the furnace, transport and ash from the hearth itself.

One glassworks from the literature: Stara Ruda

The sentences below come from the V2 material based on the work of Andrzej Wyrobisz (source 1). They were not re-checked in V3; they need to be compared with the text of the study.

  1. A starting point: the glassworks of Katarzyna Winiarska at the Stara Ruda manor farm in the Radoszyce forests, according to a privilege of Sigismund the Old. to be verified: what exactly this date means

  2. The glassworks moved to the Głownia river, near Czarny Las. According to the author, glass from this area reached the Kraków market. to be verified in the text

A name alone is not evidence. According to Wyrobisz, the names Huta and Hucisko around Radoszyce, Końskie and Kielce can also denote metal smelting. This page does not point to sites or to places where fragments of glass could be looked for.

What the material does not state

This is missing data, not zero and not a “small” value. That is why none of these points has a place in the diagram or on the timeline.

  • no dataLocation of the furnace and traces in the field
  • no dataScale of production
  • no dataBatch composition and recipe
  • no dataHow much wood, and from which trees, was used
  • no dataColour of this glassworks' products

Sources and verification status

The entries were carried over from V2. The input material gave no addresses for them, so I do not invent any: each needs a bibliographic check and a link added.

  1. 1. A. Wyrobisz (1966)

    “Liczba i rozmieszczenie hut szklanych w Małopolsce w XIV–XVII w.” [The number and distribution of glassworks in Lesser Poland in the 14th–17th centuries], Przegląd Historyczny 57/3, pp. 376–388. The basis for the sentences about the glassworks of Katarzyna Winiarska, its relocation and the Kraków market, and for the warning about place names. to be verified: text and address

  2. 2. Corning Museum of Glass: Flux

    The role of the flux (potash), which makes silica fuse more easily by lowering its melting temperature. to be verified: address and wording

  3. 3. Corning Museum of Glass: Forest glass

    A description of forest glass and of the greenish colour linked to iron in the sand. to be verified: address and wording

  4. 4. Corning Museum of Glass: Get Stoked!

    Wood fuel as a separate, key task at the glassworks furnace. to be verified: address and wording

What changed relative to V2, and why
  • The “nominal batch” slider (1–10 portions) was removed. In V2 it changed only the caption of the number of portions and affected no result, so it explained nothing.
  • The log of attempts kept in browser memory (key atlas-v2-35) was replaced with a comparison table. The six cases are visible side by side, without saving anything. V3 does not use localStorage.
  • The separate text tree was replaced with descriptions in the columns and the model result. The same state is described in words beside each button.
  • The context photograph was removed. V2 embedded remotely a modern glassblowing demonstration at the Corning Museum of Glass (USA), author Ruhrfisch, CC BY-SA 4.0 (file page on Wikimedia Commons). It did not show this glassworks, and the page is meant to work offline. This way no photograph is given a local provenance.
  • Retained: the two wood lanes, the independent sources of sand, fuel and potash, variants A and B, and the rule that the lack of one ingredient halts melting. The variants now set all four choices explicitly, felling included.
Inspirations for the form (not evidence for facts)