PRELIMINARY TO ANY LABORATORY TESTING OF COAL, IT IS IMPERATIVE that a representative sample be obtained; otherwise, the most carefully conducted analysis is meaningless. Reliable sampling of a complex mixture such as coal is difficult and handling and preparation of the sample for analysis presents further problems. Variations in coal handling facilities make it practically impossible to publish a set of rules that would apply to every sampling situation. The proper collection of the sample involves an understanding and consideration of the minimum number and weight of increments, the particle size distribution of the coal, the physical character and variability of the constituents of coal, and the desired precision.