MAGNETIC OXIDE OF IRON. 15 



possesses feeble polarity. It is almost always accompanied by hornblende, and good specimens 

 of black mica may be obtained in its immediate vicinity. Thin veins of iron pyrites arc also 

 frequently observed. The specific gi'avity of this ore is 4.729. The following is its com- 

 position, viz : 



Protoxide of iron 24 . .50 



Peroxide of iron, 66. SO 



Insoluble matters, silica, &c 8. 70 



About a mile and a half southwest of the preceding, is another bed of this ore, with similar 

 associates. The ore is of a greyish black colour, and contains grains of iron pyrites disse- 

 minated through it, which renders the operation of roasting necessary, previously to its intro- 

 duction into the furnace. It is granular, friable, and is said to furnish a softer iron than the 

 preceding, although it is less fusible. 



Cheever Mine. This is an important deposit of magnetic ore, situated about a mile and a 

 half from Port Henry, near the line of the town of Westport. It is in the primitive rock, 

 has a course about northeast and southwest, and is from seven to ten feet in thickness. It 

 has been opened for at least 900 feet, and more or less ore taken out at various points. About 

 3000 tons are aimually obtained from this mine. The ore is made up of gi-ains loosely united, 

 of a shining black colour, and it is highly magnetic. The associates are hornblende, a little 

 feldspar, and sahlite or hypersthene. 



This ore is used at the furnaces at Port Henry, and is said to yield good iron. 



The Sanford Mine, is found in the town of Moriah, about six miles west of Port Henry. 

 This is an extensive deposit of ore, and it has been quite largely worked ; but it seems now 

 to have given place to some of the other mines with wluch this region abounds. The ore is 

 usually granular, but sometimes highly polished cleavages of some size may here be obtained. 

 Like the preceding, it is strongly attracted by the magnet, but is not usually polar. The 

 associates of the ore are somewhat peculiar, and probably exert an important influence upon 

 the quality of the iron obtained from it. Veins of delicate fibrous amianthus or byssolite are 

 not uncommon, and many specimens are studded with small but perfect six-sided crystals of 

 phosphate of lime. These were observed in abundance in a heap of this ore near the Port 

 Henry furnace. This is probably one of the most troublesome associates of iron ore, espe- 

 cially when it exists in such comparatively large proportions as it seems to do in some parts 

 of the Sanford Mine. The carbon used in the furnace causes the decomposition of this 

 phosphate, and the liberation of phosphorus, which, during its contact with the iron, must 

 injure its quality.* I believe it has been usual to wash this and the other ores found in this 



* It ni:iy not be uniniportanl to add, that phosphorus, so freqviently contained in iron ores, and furnished even hy tlie ashes of 

 the combustible, does not injure the quality of iron, unless it exists in a comparatively large proportion. According to Karsten, 

 a compound of 10,000 parts of iron and 50 of phosphorus, gives an iron of good quality, which resists the blow of a hiimmcr. A 

 compound of 10,000 iron and T5 phosphorus, yields an iron which frequently breaks by a blow ; wlule an iron consisting of 100 

 piiosphoms and 10,000 iron, cannot be bent to a riglil angle. 



