04
Clay, kilns, charcoal and lime
Earth parallel: New Stone Age. Goal: control of high heat. Everything in metal depends on this phase.
| ID | Achievement | About year |
|---|---|---|
| 04.01 | The work groundkilns and charcoal, later the forge and the workshops, together at the centre and apart from the houses | 1 |
| 04.02 | Clay pit and prepared claydug, soaked, cleaned, tempered and kneaded | 1 |
| 04.03 | Hand-built potspinched and coiled | 1 |
| 04.04 | Pit-fired potteryfirst cooking pots and water jars; boiling becomes easy | 1 |
| 04.05 | Clay tablets and charcoal on barkthe first writing; the Record before there is parchment | 1 |
| 04.06 | Shadow stick, water clock and counted breathsagreed ways to time a process before there is a clock | 1 |
| 04.07 | Charcoal clampwood baked under earth into clean, hot-burning fuel | 1 |
| 04.08 | Sun-dried mud bricksmade in a wooden mould | 1 |
| 04.09 | Updraft kilnfirebox below, pierced floor, domed chamber | 1 |
| 04.10 | Kiln-fired potterystrong jars, lidded pots, bowls, lamps | 1 |
| 04.11 | Fired bricks and roof tiles | 1 |
| 04.12 | Potter's turntablefaster, rounder, thinner pots | 1 |
| 04.13 | Clay bread oven | 1 |
| 04.14 | Lime kiln and quicklime ⚠burns limestone or shells | 1 |
| 04.15 | Slaked lime, mortar, plaster and whitewash ⚠ | 1 |
| 04.16 | Lime-plastered cistern and floorsstored rain water, clean dry floors | 1 |
| 04.17 | Wood-ash lye ⚠the first chemical; water run through hardwood ash | 2 |
| 04.18 | Potashlye boiled dry; needed for soap, glass and saltpetre | 2 |
| 04.19 | Soapwashing, wound cleaning, later a lubricant | 2 |
| 04.20 | Wood tar and pitchbaked out of pine in a sealed pot | 2 |
| 04.21 | Fired clay pipes and drains | 2 |
| 04.22 | Refractory clay mixclay that survives white heat | 2 |
| 04.23 | Heat cones and the colour of heatsmall clay cones that slump at known heats, and a chart of fire colours | 2 |
| 04.24 | Cruciblessmall cups to melt metal in | 2 |
| 04.25 | Clay air nozzles (tuyeres)carry the air blast into a fire | 2 |
| 04.26 | Bag bellowsa pair of hide bags pumped by hand or foot | 2 |
| 04.27 | Forced-air charcoal furnacereaches 1100–1200 °C, hot enough to smelt copper | 2 |
| 04.28 | Sourdough starter and brewing yeastwild yeast caught in a jar of meal and water, fed every day and kept alive for years | 2 |
| 04.29 | Sand-and-charcoal water filterclears muddy water before it is boiled | 2 |
| 04.30 | Clay cooking stove with fluehalf the firewood, and the smoke goes outside | 2 |
| 04.31 | Ointments, infusions and decoctionseach herb prepared the same way every time | 2 |
| 04.32 | Gypsum plastera cast that holds a broken limb still; also moulds and smooth walls | 2 |