A number of substances have high enthalpy heats of solution, and appear to “create” cold when added to water. Some, like calcium chloride, would likely have been known in Classical Greece.
Edit: My mistake. Dissolution of calcium chloride is actually exothermic. I’m not sure if any salts which have high endothermic dissolution occur in a naturally pure state.
A number of substances have high enthalpy heats of solution, and appear to “create” cold when added to water. Some, like calcium chloride, would likely have been known in Classical Greece.
Edit: My mistake. Dissolution of calcium chloride is actually exothermic. I’m not sure if any salts which have high endothermic dissolution occur in a naturally pure state.