lignite is preferable. With automatic stokers the coal is commonly preferred in a fine state, and they seem especially adapted to the use of lignite. The woody structure of lignite is one of its characteristics. Often slabs and logs occur in the seam, which preserve nearly every detail of their original structure. When a seam is made up of this material, with no admixture of foreign matter, it is tough and compact and furnishes fuel of excellent quality. The prevailing color is brown, though some seams appear a dull black. When exposed to the air for a long time thin bands become glossy black, resembling jet, and burn like pitch. A layer of "slack" often forms the top of a lignite seam, sometimes attaining a thickness of eight feet. It seems to be lignite which has decayed in the air while the lower part of the seam was preserved under water. Its fuel value is probably low. An analysis gives 22 per cent of ash. Often an entire seam is made of this "slack" coal, though such seams are usually thin. In prospecting it is sometimes difficult to determine whether the slack exposed at the surface is due to the disintegration of a good seam or whether the whole seam is slack. In general, it may be said that if the quality does not materially improve on drifting in six feet the entire seam is soft. In connection with a briquetting device, this soft or slack lignite may be utilized, but at present it has little worth. The following tables summarize the results of analyses that have been previously given in the county reports. A description of the locality from which the samples were taken may be found by referring to the index. In each case the moisture was driven off and its amount computed, and the fixed carbon, volatile matter and ash reckoned on the dry basis. In Table I great care was taken in nearly every case to bring the samples to the laboratory in just the condition that they left the mine, and the percentage of moisture is consequently high. In Tables II and III no special care was taken to prevent the samples from drying. Table I.-Analyses showing moisture in material fresh from mine. Fixed carbon, volatile matter and ash computed on dry lignite is preferable. With automatic stokers the coal is commonly preferred in a fine state, and they seem especially adapted to the use of lignite. The wa Often slat every deta up of this tough and prevailing black. W become gl A laye sometimes lignite wh seam was low. An seam is ma thin. In whether th tion of a general, it improve or In cont lignite ma The fol have been tion of the found by r driven off: tile matter In Table the sample the mine, a In Ta sam |