No. 275.] 47 
In addition to the above^ two artificial compounds of iron deserve to 
be noticed. The one is the graphitic iron^ containing variable propor- 
tions of graphite and iron, from a rejected hearthstone of the Southfield 
furnace, in Orange county : The other, a silicate of iron, in crystals , 
from the works of the Messrs. Pierson at Ramapo, Rockland county. 
The latter contains, according to the analysis of Dr. Fisher, — protoxide 
of iron 70, and silica 30, in 100 parts. 
Manganese. 
74. The ore of this metal which is most common is that which from 
its colour is called the black oxide of manganese. It generally has a 
brownish black or iron black colour, an earthy appearance, and it is 
usually mixed with other substances, as silica, alumina, oxide of iron, 
and carbonate of lime. It is often friable, easily reducible to powder, 
and strongly soils the fingers; sometimes, however, it has a fibrous tex- 
ture, the fibres radiating from a common centre. 
From recent researches it appears that the variety known by the name 
of wad, differs in containing a portion of water, and it has received the 
chemical name of hydrated peroxide of manganese, although the varie- 
ties of this oxide are indiscriminately applied to the same uses in the 
arts. These are in the preparation of chlorine for bleaching, and in 
the manufacture of glass. 
My report of last year contained a notice of a locality of wad oc- 
curring on Tug Hill, in Lewis county. Prof. Mather, in his report for 
the same year, describes several important localities of the same sub- 
stance in the counties of Columbia and Dutchess; and he asserts that 
50,000 tons of wad could be procured in these counties without any 
great expense. If carefully prepared it would be worth $20 a ton, or 
for the whole amount $1,000,000. 
75. The following table will exhibit the composition of such speci- 
mens of wad as I have been able to obtain. 
