\\-ll.IJAM SIEMENS, I'.R.S. 133 



manner in which it is prepared for the market. The raw anthra- 

 cite as it comes from the mine is raised to the top of a wooden 

 structure some 60 to 70 feet high, in descending through which 

 it is subjected to a series of operations of crushing, dressing, 

 sieving, and separating of slaty admixtures, and is then delivered 

 through separate channels into railway wagons, as large-coal, egg- 

 coal, walnut-coal, and pea-coal, each kind being nicely rounded 

 and uniform in size. The dust coal, which amounts to nearly 

 one-half of the total quantity raised, is at present allowed to 

 accumulate near the mine, but experiments are now being carried 

 out to utilise this also for steam-boiler purposes. 



Next in importance to mineral fuel, properly speaking, come 

 lignite and peat, of which vast deposits are met with in most 

 countries. These may be looked upon as coal still in course of 

 formation, and the chief drawback to their use, as compared with 

 that of real coal, consists in the large percentage of water which 

 they contain rendering them inapplicable, in their crude condition, 

 to the attainment of high degrees of heat. These difficulties 

 may be overcome by subjecting the wet material to processes of 

 compression, desiccation, and coking, whereby excellent fuel and 

 products of distillation are obtained ; but the cost of their pro- 

 duction has hitherto exceeded their market value. Crude air-dried 

 peat has, however, been rendered applicable for obtaining high 

 degrees of heat such as are required for metallurgical operations, 

 by means of the regenerative gas furnace ; and it is important to 

 observe that the calorific value of a ton of air-dried peat or 

 lignite, if used in this manner, is equal to that of a ton of good 

 coal, if in both cases deduction is made of the percentage of 

 moisture and earthy matter. The carbonaceous constituents of 

 peat yield indeed a very rich gas suitable for melting steel or for 

 re-heating iron, the only precaution necessary being to pass the 

 gas from the producer over a sufficient amount of cooling surface 

 to condense the aqueous vapour it contains, before its arrival at 

 the furnace. This precaution is not necessary, however, in dealing 

 with some of the older lignites, such as occur abundantly in 

 Austria and Hungary, which may be ranked as almost equal 

 in value with real coal, except for blast-furnace purposes. 



Fuel also occurs naturally in the gaseous condition, a fact but 

 too well known to every practical coal minor. Occasionally, how- 



