94 Transactions of the American Institute. 



EXHIBIT J. 



Calculation" of the Log of the Blanchard Boiler, exhibited ai 

 the Fair of the American Institute, November, 1871. 



Determination of the heat carried away by the condensing water dis- 

 charged from the tank during the twelve hours trial. 



Units. 



To 10.30 a. m., 140 cub. ft. @ 62£ lbs. =8750 lbs. @ 



range of 72°.l Fahr.= 630,875 . 



To 8.56 p. m., 2805 cub. ft. @ 62£ lbs. =175,312.5 



lbs. @ range of 61°.74 Falir.= 10,823,793.75 



To 9.26 p. m., 120 cub. ft. @ 62£ lbs. = 7500 lbs. @ 



range of 23°.46 Fahr.= 175,950. 



(a) Total British thermal units 11, ,630, 618. 75 



Determination of heat carried off by evaporation at the surface of 



the tank. 



Units. 



258.33 lbs. x 1040M7 (latent beat at 106°.14 Fahr.=(5) . . 268,707.12 

 Determination of heat carried aioay by water of condensation. 



Units. 



10,152.5 lbs. @ 5°.09 (range =49°. 49— 44°.4)=(c) 51,676.23 



Total heat derived from fuel, as determined above. 



Thermal units. 



11,630,618.75 + 268,707.12 + 51,676.23= 11,951,002.10 



Deduct four per cent of (a) for errors (leakage and 



meters 465,224.75 



Final and corrected result 11,485,777.35 



British thermal units per lb. combustible, 11,485,777.35-^-1047.5 = 

 10,964.94. 



Equivalent evaporation of water, temperature 212° Fahr., atmos- 

 pheric pressure=10,964.94-=-966.6=11.34 lbs. 



Total weight of water actually evaporated bj equation, Ex—h 

 ( W—x )= u, where 



iZ=heat transferred by each lb. of steam. 

 h =heat carried into tank by each lb. of water. 

 x = weight of steam, in lbs. 

 W=* weight of feed. 

 £7=total quantity of heat. 

 1157.69a; + 256.14(10152.5-a')=ll,4S5,777.35. 

 x =9855.60 lbs. steam. 

 W—x =296.90 lbs. water. 



Apparent results. Real results. 



Water evaporated per lb. of coal. . *\^ 3 %- 6=8.24 g f iga q == 8 - 00 



Water evaporated per lb. of com- 

 bustible . . •VoV¥rr-= 9 - 69 IIU J= 9 -41 



