Tier 2 — Forge
Metal is the first genuine force multiplier: an iron axe fells in a day what a stone axe fells in a week, and every subsequent tier is paid for by that surplus. Writing is the second, and it is the one that outlives you.
2
Forge
Get above 1,100 °C and keep a written record. These two moves open more doors than everything below them combined.
Energy used: Bronze and Iron Age societies sit between Cook's primitive (12,000) and advanced (26,000) agricultural stages; he gives no figure for them. · where civilization stands
Binding constraint. The binding constraint is fuel, not ore. Bog iron and surface copper are common; sustained high temperature is not. A single bloomery smelt eats a stack of charcoal that takes a week to burn and a hectare of coppice to grow. Groups that skip charcoal and try to smelt with raw wood never reach temperature and conclude, wrongly, that they have no ore.
t2-charcoal
Make a fuel that burns hot enough to melt metal.
Energy
Guide ×5Build ×2Sheet ×16
Produces fuel capable of 1,200 °C+
t2-smelt
Extract metal from rock.
Materials
Guide ×6Build ×4Sheet
1,100–1,300 °C
t2-smith
Shape metal into tools — including the tools for shaping metal.
Tools
Guide ×2Build ×4Sheet
800–1,300 °C
t2-lime
Burn limestone and unlock mortar, plaster, flux, and disinfection.
Materials
Guide ×6Build ×2Sheet ×10
900 °C+
t2-brick
Make a standard, repeatable building unit — and something that will line a furnace.
Materials
Guide ×3Build ×3Sheet ×10
900–1,100 °C
t2-masonry
Walls of fired brick or stone in lime mortar, a roof that does not burn, and a chimney that takes every trace of smoke out of the house.
Shelter
GuideBuildSheet ×10
t2-barn
House the herd and its winter fodder so that the bedding stays dry, the air stays below the ammonia limit, the hay cannot burn the byre or the house, and nothing from either reaches the well or the people.
Shelter
Hay core: pull it apart at 66 °C; at 79 °C stop the air and call fire cover
Floor fall 1.5–2 % to the channel; ridge slot 5 cm per 3 m of building width
t2-writing
Move knowledge out of heads and onto something that outlives them.
Knowledge
t2-school
Build the institution that makes knowledge survive a death.
Knowledge
Guide
t2-wheel
Move heavy things further than you can carry them.
Transport
GuideBuild ×2
t2-plank-boats
Build boats of planks that carry a family and its goods, row them with oars sized by rule, and add a sail only to a boat that passes the stability test.
Transport
GuideBuildSheet ×8
t2-kites
Fly kites that carry a line across a river or a gorge, lift an aerial or a signal, and show how a surface held at an angle to the wind makes lift.
Transport
GuideBuildSheet ×5
t2-irrigate
Put water where the crop is, when the crop needs it.
Food
Guide ×5Sheet ×2
t2-fishpond
Grow a crop of fish in a fenced, drainable earthen pond that holds its water, keeps the dawn oxygen above the species' minimum, and is drained, harvested and dried each cycle.
Food
GuideBuild
Nile tilapia grow best at 27–30 °C and are in danger below 12 °C; common carp 23–26 °C
Secchi disc 40–60 cm; dawn oxygen above 3–4 mg/l
t2-brew
Put microbes to work — your first biotechnology.
Materials
Guide ×4Build
78 °C (ethanol boiling point)
t2-medicine
Build a small, honest pharmacopoeia from what grows locally.
Health
Guide
t2-numeracy
Make counting, measuring and reckoning ordinary rather than specialist.
Knowledge
Guide ×3
t2-writtenlaw
Put the rules where everyone can read them, and separate judging from ruling.
Society
Guide
t2-weights
Give every market a balance whose readings can be checked and a set of reference weights within published tolerances, held to a master by an office that verifies, stamps and re-inspects them.
Economy
Guide
Trade weights within OIML class M tolerances: 1 kg to ±50 mg (M1), ±160 mg (M2) or ±500 mg (M3)
t2-census
Count every person and dwelling as at one date, so that decisions about food, water, schools and shares start from a number rather than a guess.
Society
Guide
t2-plot
Lay out the settlement before it lays itself out.
Settlements
GuideBuild