The determination, by chemical methods, of the proportionate amounts of various constituents of coal. Two kinds of coal analyses are ordinarily made: (1) proximate analysis, which divides the coal into moisture (water), volatile matter, fixed carbon, and ash. Percentage of sulfur and heat value in Btus per pound or kilogram, each obtained by separate determination, are usually reported with the real proximate analysis; and (2) ultimate analysis, which determines the percentages of the chemical elements carbon, hydrogen, oxygen, nitrogen, and sulfur. Other elements that may be present are considered impurities and are reported as ash.