152 GEOLOGY OF OHIO. 
vitiates or even nullifies many of the practical tests to which the coals 
are subjected. Unless each coal has been so treated as to ensure its 
best results, the so-called test is unfair and deceptive. One locomotive 
engineer will complain of a coal that it “smuts the flues.” Another 
will use coal from the same mine without experiencing the slightest 
tendency to this trouble. } 7 
Ash, sulphur and slate that tend to run on the grate and form 
“clinker,” or that accumulate so as to deaden the fire, are the elements 
that are most obnoxious in our steam coals. 
3. For blast furnace use, only the best and purest of our open- 
burning coals are available in the raw state. There are four fields from 
which such coals are taken, viz., the Mahoning Valley, the Massillon 
district, the Hocking Valley, and the Jackson county district. The 
first of these regions has furnished the type and standard of this class 
of fuels hitherto, but its day of service in this field has gone by, and it 
is now almost entirely displaced on its own ground by the great iron 
making fuel of the Ohio Valley, Connellsville coke. The Massillon 
coal has not as happy an adaptation to this use as the coal already 
named, and has never been applied to iron making in the large way. 
But very little of it is used in furnaces at the present time. 
The Hocking Valley coal in its best phases is well adapted to iron 
manufacture, and a great and growing industry is already established 
upon it in this connection. 
The two seams of Jackson Court House and vicinity, viz., the Shaft 
coal and the Hill coal, are both largely and successfully used in the 
furnaces of the district to which they belong. 
4. There is but one field of the State in which coal is mined 
expressly for coking. The small coal and slack of several districts go 
to the coke ovens, but in Leetonia alone is the whole product of the 
mines brought to the ovens.* ‘This is the only coke now made in Ohio 
that is used in iron smelting. The Shaft coal of Steubenville has been 
largely used in this way in the past, but it, too, has succumbed to the 
superior quality and lower price of Connellsville coke. 
The coke now made in the State is chiefly manufactured from the 
small coal and slack that accumulate in mining. The impurities of the 
seam are often gathered here in large amount, and the coke that results 
shows their presence by excessive ash and sulphur. These cokes are 
* The Hammondsville Strip Vein is mined for coking also, but the output is insignificant. 
