Imagine you have no technology other than fire, stone, wood and bone. How would you cook food, other than directly by roasting it over an open fire, when you don’t have any pots or metal containers that will withstand heat?
The answer is you have a pot boiler. A pot boiler is a stone which you place directly in a fire until it’s extremely hot. You then take it out using wet wood and place it into a lined stone container full of water. The stone cools down suddenly and the water heats up. Keep doing it and you have lovely warm water to bathe or boiling hot water to cook in. A few fizzing stones will keep your beef stew with dumplings cooking nicely. It’s simple but incredibly effective technology.
On Westray there are neolithic, bronze age, iron age and Viking remains seemingly everywhere. Along the sea shore I see an eroded sand bank with a beautiful dark line of a rubbish dump, called a midden. It is full of limpet shells and bones.
This midden must have been there well over 1,000 years. At the base of the sand dunes is this pebble, freshly eroded from the midden. It’s crazed from the shock of being plunged into cold water.
I’m crazed from the shock of finding it.