IRON MANUFACTURE. 551 
have yielded Dr. Wormley as high as 2 per cent. of the ash, though 
generally much less. 
It certainly would pay to have the ashes examined for phosphorus 
before using a new coal, especially where the lake ores are used to ¢arry 
mill cinder, as is now so generally done in the State. The cinder being 
very cheap, the more that can be used the better, provided the quality 
of the iron does not suffer. 
Another source of phosphorus is the limestone. All limestone 
contains traces of this element. Analyses in the Ohio State University 
laboratory have shown the following percentages in limestones used for 
furnace purposes : 
Phosphorus.......... ...- miles aise aitelsccians Caciovataneecisee enc ales 067 .035 052 14 
land 2. Owen’s Quarry, used by Winona furnace. 
3 and 4. Shawnee limestone. 
Occasionally the per cent. becomes very large. A layer in the 
Columbus quarries contains in certain specimens as high as 8 or 10 per 
cent. of phosphoric acid, and this material occasionally gets into cars 
loaded for the Hocking Valley furnaces. 
The extensive use of mill cinder has been discussed somewhat. 
The peculiarity of this material is its highly silicous character and its 
fusibility. Its variability in percentage of phosphorus and of iron has 
been shown, but besides these drawbacks, without great care in smelting, 
itis liable to reach the hearth of the furnace unreduced, when it acts as 
a corrosive slag, and also makes masses of wrought-iron collect there, the 
oxide of iron in the slag acting as a decarbonizer on the iron in the 
hearth. 
A furnace at Steubenville was during 1880 running almost exelu- 
sively on mill cinder; the campaign was successful, a fair mill iron 
being produced. When the furnace was blown out, a mass of wrought- 
iron or salamander at least 6 feet in diameter was removed from the 
hearth of the furnace. 
The method of treating these salamandevs was curious; they were 
drilled into by a steel drill to a depth of two-thirds or more the di- 
