THE HAMILTON ASSOCIATION. 31 
The experiment was made last September at the Isabella 
furnaces of the Carnegie Steel Co., at Pittsburg, of drying the 
air before blowing it in the furnace, by means of refrigera- 
tion. The air is passed over pipes containing a brine by which 
the air is cooled to such a degree that the moisture is condensed 
into water and frost. The air enters the furnace practically 
dry, and the immediate result was to reduce the fuel consump- 
tion nearly 25 per cent. Before using the dry blast the furnace 
averaged for two weeks 340 tons per day, with a fuel consump- 
tion of 2,200 Ibs. of coke per ton of iron. Without making any 
other change the dry blast was introduced, and for two weeks 
following the output was nearly a hundred tons a day more, and 
the fuel consumption 1,700 lbs. per ton of product. 
There is one more illustration drawn from the iron industry 
where chemistry has been a very great aid in securing economy 
of operation, which is applicable to all cases where power is pro- 
duced from the combustion of coal. Analysis of the com- 
position of coal and determination of the heat evolved 
‘in the combustion of its elements has shown that but 
a very small part of the energy of the coal is developed into use- 
ful motion. The best boilers constructed and maintained under 
the best conditions do not show more than 65 per cent. of the 
energy of the coal in the form of steam, and the best engines do 
not develop more than one-third of the energy of the steam into 
useful motion. Now, these are the best types and they show that 
with combination of engine and boiler not more than one-fifth of 
the energy of the coal is transformed into motive power. We 
must remember that chemists have done a great deal to show 
what is the most suitable amount of air and the best design of 
grates and combustion chamber in order in the first place to get 
the coal properly burned. They have done enough to show that 
with proper grate surface and sufficient air supply and combus- 
tion chambers of the proper temperature, there is no necessity 
for factories using the worst kinds of soft coal to contaminate 
our atmosphere and soil our best buildings with dense clouds 
of black smoke. So that when we speak of engines showing 20 
per cent. efficieuey, we are already indebted to chemistry, for it 
