506 WISCONSIN AGEICULTUEE. 



Experience proves, what might be anticipated from the an- 

 alyses of the ores, namely: that the surface ores are the least 

 refractory in the furnace, and there can be no doubt but a 

 free exposure to atmospheric influences of the ore, will very 

 much improve both their working properties in the furnace 

 and also the character of the iron ; especially those containing 

 the phosphate of lime. This last constituent of the ore — 

 phosphate of lime — is doubtless derived from animal remains, 

 fragments of which in the form of small shells are occasionally 

 met with in the ores, being most abundant in those specimens 

 having the largest percentage of the phosphate of lime. 



The surface ores work the best in the furnace, and the des- 

 ignation of "best upper bed," "best lower bed," &c., at the 

 head of the detailed analyses have reference to their furnace- 

 working properties. There are two analyses of the "best up- 

 per bed" as designated. One of these is of the lumpy or more 

 compact ore ; the other of a dark brown color, and generally 

 in lumps also. These ores do not constitute any very consider- 

 able portion of the bed, but they are occasionally found both 

 in the lower and upper surface ores. These are found to be 

 always refractory in the furnace, as are also the hard and dry 

 ores from the lower part of the upper bed. 



Throughout the whole bed the nodules are mixed in more or 

 less with earthv matter and their ordinary working yield is 

 about forty-two per cent., or forty after being wet up, as it is 

 usually put into the furnace. 



NO. I, "BAD UPPER BED." 

 This is a compact brown ore of a granular character. On 

 heating the powder of this ore to 212° it lost two per cent, of 

 its weight. 



Specific gravity, 2.993 



Peroxide of iron, 41.67 



Carbonate of Lime. 15.48 



Carbonate of Magnesia, 8.25 



Peroxide of Manganese, 2.56 



Phosphoric acid, 1.53 



Alumina, 12.74 



