1 88 APPENDIX. 



should be caught and weighed, and the percentage of moist- 

 ure computed therefrom added to that shown by the calo- 

 rimeter. 



Superheating should be determined by means of a ther- 

 mometer placed in a mercury-well or oil-well inserted in the 

 steam-pipe. 



For calculations relating to quality of steam and correc- 

 tions for quality of steam. 



XIV. Sampling the Coal and Determining its Moisture. 

 As each barrow-load or fresh portion of coal is taken from the 

 coal-pile, a representative shovelful is selected from it and 

 placed in a barrel or box in a cool place and kept until the 

 end of the trial. The samples are then mixed and broken 

 into pieces not exceeding one inch in diameter, and reduced 

 by the process of repeated quartering and crushing until a 

 final sample weighing about five pounds is obtained, and the 

 size of the larger pieces are such that they will pass through 

 a sieve with J-inch meshes. From this sample two one- 

 quart, air-tight glass preserving-jars, or other air-tight vessels 

 which will prevent the escape of moisture from the sample, 

 are to be promptly filled, and these samples are to be kept 

 for subsequent determinations of moisture and of heating 

 value, and for chemical analyses. During the process of 

 quartering, when the sample has been reduced to about 100 

 pounds, a quarter to a half of it may be taken for an approxi- 

 mate determination of moisture. This may be made by 

 placing it in a shallow iron pan, not over three inches deep, 

 carefully weighing it, and setting the pan in the hottest place 

 that can be found on the brickwork of the boiler setting or 

 flues, keeping it there for at least twelve hours, and then 

 weighing it. The determination of moisture thus made is 

 believed to be approximately accurate for anthracite and 

 semi-bituminous coals, and also for Pittsburg or Youghio- 

 gheny coal ; but it cannot be relied upon for coals mined 

 west of Pittsburg, or for other coals containing inherent 



