An oil is a fluid light enough to float on water. It will not mix with water but will combine with alcohol. It remains fluid at normal temperatures. This distinguishes the oils from fats, which are solid at normal temperatures.
   A few oils come from fishes and other animals, such as fish oils and fish-liver oils, whale oil and neat's-foot oil. The latter is processed from the feet of animals at meat-packing plants. Sperm oil from the whale is not a true oil but a liquid wax.
   Most of our useful oils are obtained from the ground, as are petroleum and other mineral products, or from plants.
   The ancient Chinese, Hindus, Egyptians, Greeks and Romans obtained vegetable oils by milling and pressing various plant parts. Today most vegetable oils are obtained by heating or steaming methods.
Many different kinds of plant life provide useful oils: almond oil (from the nuts), castor oil (from the seeds of the castor bean), coconut oil (from kernels of nuts), corn oil (from the kernels), cottonseed oil, olive oil (from the fruit), peanut oil (from the peanuts), and soybean oil (from the beans). Petroleum and the products made from it are used as fuels and in chemicals.
   Some of the important uses for oils of various kinds are in lubrication, flavoring, perfume, and medicines.