DEPARTMENT OF METALLURGY AND ECONOMIC GEOLOGY. 249 



iiuiividual or eompauy or even State could undertake, and evou if a 

 State should undertake to investigate its own coals the results obtained, 

 so far from lilling the need, would only the more clearly demonstrate 

 the necessity of .including all the coals of the country iu one investiga- 

 tion under one central authority. 



In view of the foregoing facts the following plan for a new and com- 

 plete Investigation of American coals has been prepared: 



(1) Each coal furnished for investigation to be submitted to a pre- 

 liminary examination, both in the laboratory and practically, to deter- 

 mine its relationships and affinities. 



(2) The coals to be divided into several classes according to the re- 

 sults of this examination, especially as regards the volatile matter con- 

 tained. 



(3) Each coal to be submitted to a series of tests on a practical scale 

 to determine its fuel value. 



(4) An examination to be made to determine the manner of combina- 

 tion of the chemical elements in the coals. 



(1) In the preliminary examination it is designed to include nearly all 

 the coals of the country, but the results of this examination will un- 

 doubtedly show so much similarity that in many cases a single coal can 

 be selected for further examination which shall fairly represent several. 



(2) It is essential to divide the coals into classes iu order to prescribe 

 the conditions of the practical tests, which should manifestly be differ- 

 ent for a hard dry anthracite containing only (5 to 8 per cent, of volatile 

 matter, from those of a soft bituminous coal with 30 per cent, or more, 

 of volatile matter. 



(3) The determination of the fuel value of the coals is the prime aim 

 and object of the investigation. 



To accomplish this end it is proposed to subject the coal to combus- 

 tion on a practical scale, under a boiler, or rather boilers, provided with 

 suitable ap[)licances' for controlling the conditions of the combustion, 

 measuring the work accomplished by the iwunds of water evaporated 

 by one [)ound of coal. 



In order that the results obtained shall be of any practical value it 

 is absolutely necessary that they should be strictly comparable. Hav- 

 ing the coal divided into classes it is necessary, in order to obtain com- 

 parable results, to test each of a given class under as nearly as possible 

 the same conditions. If now the investigation is limited to a single set 

 of conditions for each cla>s of coals, as was done by Professor Johnson, 

 then the practical application of the results will also be limited to the 

 same or similar conditions, and should tliey be applied to different con- 

 ditions would surely lead to false results. Hence it is proposed to 

 adopt several sets of conditions for each class of coals. Again, asmgle 

 experiment will not giv(! a satisfactory or true result, and it becomes 

 necessary to make several tests uinUu' each set of conditions. So that, 

 filially, iu order loobtain thoroughly satisfactory results, each coal should 



