180 



BOILEB TESTS. 



The tests on Boiler No. 49 had for an object the determina- 

 tion of the general economy of this form of boiler, the rela- 

 tive economy of Cumberland coal and anthracite chestnut No. 

 2 coal, and the loss occasioned by banking fires. The results 

 all show a very low degree of economy. That obtained on 

 Test No. 97 is more than 25 per cent, inferior to the best 

 results obtained on boilers of approved type. Attention needs 

 only to be directed to the deficient heating surface, and the 

 consequent large amount of waste heat in the gases, which in 

 this case were hot enough to melt zinc, to account for the 

 result. Comparing Test No. 99 with Test No. 97, the evap- 

 oration per pound of chestnut No. 2 coal is 26 per cent, less 

 than that of Cumberland coal. The loss produced by banking 

 a Cumberland coal fire, as indicated by Tests No. 97 and No. 

 98, appears to be 2 per cent. 



Boiler No. 5O. 



Kind of boiler, 



Number used, ...... 



Horse-power ( collective, makers' rating). 



Kind of coal, 



Age, 



Galloway. 



Six. 



One thousand, four hundred 



and forty. 



George's Creek Cumberland. 

 Three months. 



Boiler No. 50 consists 

 of a plant of six Gallo- 

 way boilers, having the 

 general features shown in 

 the following cuts. This 

 is an internally fired boiler 

 having two furnaces in 

 each shell. The heat- 

 ing surface consists largely 

 of vertical water tubes of 

 conical shape, which ex- 



BOILKR NO. 50, CltOSS SECTION THROUGH 



FUKXACKS tend from top to bottom 



of the large flue which passes from the combustion chamber at 

 the end of the furnaces to the end of the boiler. The products 

 of combustion, on leaving the furnaces, pass forward through 

 this flue, thence backward beneath the shell, finally entering 



