A large can used to store dry foods long term, normally with an oxygen absorber. See ch. 22.
1-10-1 rule
When you fall into cold water: 1 minute to control your breathing, about 10 minutes of useful movement, and around 1 hour before losing consciousness from hypothermia. See chs. 13 and 14.
7-10 rule
Each time the time since a nuclear explosion is multiplied by 7, the radiation from fallout drops to one tenth. At 49 hours about 1% of the first hour's level remains. Seech. 15.
