This section of the book is from the "Household Companion: The Model CookBook" book
Ice (or snow) and salt are necessary for freezing cream, fruit, etc. Salt melts the ice, and in melting it absorbs heat from the cream, thus causing the cream to freeze. For each cup of rock salt used, allow three cups of broken ice. Pound ice in a bag or piece of carpet.
To pack the freezer: Put three cups pounded ice around the can, then sprinkle one cup of rock salt, and pack in alternate layers of ice and salt until within an inch of the top of the can. Let it stand from ten to twenty minutes to chill, then turn or beat until the cream is frozen. Pack away with ice and salt around and over the can.