In this, the first attempt to give in English a comprehensive review of petrographic methods, it cannot be otherwise than that there should be many omissions—it is to be hoped not many errors. If any is found the author will be extremely glad to have his attention called to it, as he will also be for criticisms, or suggestions for additional material that should be included.

This book is the third in a series of three, intended primarily to provide a working manual for laboratory technicians and others engaged in the testing of soils for building and engineering purposes. It is not meant in any way to be used as a substitute for the Standards referred to therein, but to augment their requirements by the provision of step by step procedures. This third edition has been revised to take account of the current requirements of BS 1377: 1990,

THREE A S TM STANDARDS are available for sampling coal: ASTM Practice for Collection of Channel Samples of Coal in the Mine (D 4596), ASTM Test Methods for Collection of a Gross Sample of Coal (D 2234), and ASTM Practice for Collection of Coal Samples from Core (D 5192). The first two standards are applicable only to existing mining operations, test pits, or transportation of coal.

After decades of using only one map projection, the Polyconic, for its mapping program, the U.S. Geological Survey (USGS) now uses several of the more common projections for its published maps. For larger scale maps, including topographic quadrangles and the State Base Map Series, conformal projections such as the Transverse Mercator and the Lambert Conformal Conic are used. Equal-area and equidistant projections appear in the National Atlas.