'JhaV. XXVIII.] USES OF MANGANESE IN METALLURGY. 
583 
It was made by smelting an intimate mixture of oxide of manganese and coal-tar. 
By the addition of this material, it was foimd that the low grade 
steel made from the Wootz ore could be converted into an excellent product, easily 
malleable and weldable.' 
He later improved his process by moulding the manganese oxide 
and tar into bricks, drying them by heating in a closed vessel, and using 
them in their raw state. 
' In this form he soon found an extensive demand for this manganese comf)ound 
among the steel manufacturers, who, after the first trial, realized the great advantage 
derived from it. Heretofore the best quality of steel in England had been made 
of high grade and expensive bar-iron from Sweden and Russia, but by the employ- 
ment of Heath's process it was possible to make an equally good product from a 
comparatively low grade iron of English manufacture.' 
Heath lost the benefit of his researches through neglecting to patent 
the use of his mixture in the raw state. D. Mushet calculated that the 
immediate result of Heath's invention was a reduction of £30 to £40 in 
the price of good steel, with an aggregate saving up to 1855 of £2,000,000. 
The Bessemer process for making steel was made public in 1856 
and perfected by 1858, the difficulties experienced in the early working of 
the process, owing to the burning off of all the carbon in the converter, 
being obviated by the introduction by Robert Mushet in 1856 of a 
' triple compound ' of iron, manganese, and carbon, an early form of the 
alloy later called spiegeleisen. This alloy was used in the Bessemer 
process for adding to the steel the requisite amount of carbon, the manga- 
nese performing various offices, then not properly understood. The 
need for an alloy containing a higher percentage of manganese than 
that in the spiegeleisen then made (5 to IO^q of manganese and some- 
times 6 to 7% of carbon) soon arose, and as the results of some experi- 
ments carried out by W. Henderson of Glasgow, at the instigation of 
Bessemer, a ferro-manganese containing 25 to 309o of manganese was 
produced in 1865. A little previous to this, however, Dr. Prieger of Bonn 
seems to have already succeeded in making a high-grade ferro-manganese. 
The process was taken up by the Terre Noire Company of France, and 
from about this date a greatly increased demand for manganese-ore 
sprang up (see account of fluctuations of price of manganese ores given 
on page 414 , 
Spiegeleisen is an alloy of iron and manganese containing usually 
5 to 27% of manganese and 4 to 5% of carbon. 
Spiegeleisen and ferro- j^. ghows mirror-like reflecting surfaces on frac- 
manganese. , . , . 
tures, and hence the name, which is the German 
for mirror -iron. 
