APPENDIX. 183 



if possible, be of some kind which is commercially regarded 

 as a standard. For New England and that portion of the 

 country east of the Allegheny Mountains, good anthracite egg 

 coal, containing not over 10 per cent of ash, and semi- 

 bituminous Cumberland (Md.) and Pocahontas (Va.) coals are 

 thus regarded. West of the Allegheny Mountains, Poca- 

 hontas (Va.) and New River (W. Va.) semi-bituminous, and 

 Youghiogheny or Pittsburg bituminous coals are recognized 

 as standards.* There is no special grade of coal mined in 

 the Western States which is widely recognized as of superior 

 quality or considered as a standard coal for boiler-testing. 

 Big Muddy lump, an Illinois coal mined in Jackson County, 

 111., is suggested as being of sufficiently high grade to answer 

 the requirements in districts where it is more conveniently 

 obtainable than the other coals mentioned above. 



V. Establish the correctness of all apparatus used in the 

 test for weighing and measuring. These are : 



1. Scales for weighing coal, ashes, and water. 



2. Tanks or water-meters for measuring water. Wat'er- 

 meters, as a rule, should only be used as a check on other 

 measurements. For accurate work, the water should be 

 weighed or measured in a tank. 



3. Thermometers and pyrometers for taking temperatures 

 of air, steam, feed- water, waste gases, etc. 



4. Pressure-gauges, draft-gauges, etc. 



The kind and location of the various pieces of testing 

 apparatus must be left to the judgment of the person con- 

 ducting the test, always keeping in mind the main object, 

 i.e., to obtain authentic data. 



VI. See that the boiler and chimney are thoroughly heated 

 before the trial to their usual working temperature. If the 



* These coals are selected because they are about the only coals which 

 contain the essentials of excellence of quality, adaptability to various kinds 

 of furnaces, grates, boilers, and methods of firing, and wide distribution 

 and general accessibility in the markets. 



