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ther from a compact form, in which the individuals are imperceptible, 
to those which are quite large and cleavable. 
These are the varieties, also, which are recognized by the miner' 
though he distinguishes them by different names, viz. the hard and 
soft. The hard variety includes those ores which are more or less 
compact, shining and difficult to break, or those which mineralogists 
call tough instead of hard. The soft are the granular kinds, which 
may be broken readily with the hammer, and passing from the mode- 
rately tough, to those kinds which are easily broken in the hands, and 
fall into grains. The latter is generally known as the shot ore, from 
the resemblance which the grains have to shot. This last is most ge- 
nerally an excellent variety of ore, and works easily in the forge ; it 
furnishes, also, a softer iron than the tougher ores. 
SECTION II. 
Chemical Characters. 
The magnetic oxide is a compound of the protoxide and peroxide of 
iron, in proportion of 31 per cent of the former to 69 of the latter. 
Before the blow-pipe, it is infusible per se, but when exposed to an in- 
tense heat, it assumes a brown colour and loses its magnetism. It 
dissolves in warm muriatic, but not in nitric acid. 
SECTION III. 
Geological Relation of the Species. 
In the United States, the magnetic oxide occurs in talcose, mica and 
chlorite slates ; both in disseminated crystals of the octahedral form, 
and in veins and insulated masses, more or less extensive. It also oc- 
curs in gniesSj granite and hypersthene rock. In the latter, the veins 
are thick and heavy. So far as observation has been made, this spe- 
cies is confined to locks of the primary class. The largest masses 
have been found in connexion with that variety of granite which is de- 
nominated hypersthene rock in the New-York Geological Reports. In 
this country, it occurs in less quantity in chlorate slate than either of 
the other rocks which have been mentioned. 
SECTION IV. 
Localities. 
The wide distribution of the species in the United States, renders 
it inexpedient to mention all the known places at which it has been 
found. 
