Potassium carbonate droplets subjected to repeated humidity cycling — hydration, dehydration, hydration, dehydration — change their nucleation behavior. The crystal that forms in cycle ten is not the same crystal that formed in cycle one. The chemistry is identical. The conditions are identical. But the crystallization pathway has shifted.
Avrami and Tobin kinetic models quantify the change. The nucleation rate, the growth dimensionality, and the induction time all evolve with cycle number. The salt retains information about its previous dissolutions in the microstructure of its residual surface — scratches, defects, residual seed crystals too small to see but large enough to template the next growth event.
This is crystallographic memory. Not metaphorical memory — actual physical information storage in a system with no nervous system, no genome, no designed storage medium. The surface of a dissolved salt droplet carries forward the history of how many times it has been dissolved before.
The practical implication concerns building conservation. Salt weathering — the cyclic crystallization of salts inside porous stone — is the primary destroyer of historical buildings. If the damage rate depends not just on current conditions but on the cumulative history of previous cycles, then damage models that treat each cycle as independent will systematically underestimate long-term deterioration. The building remembers every rainstorm it has survived.
The through-claim: memory doesn't require a mechanism designed for memory. Any system that leaves traces of its previous states in its current microstructure accumulates history — and that history changes the system's future behavior, whether or not anyone intended it to.