Prof. Johnson'' s Report on the Bradford Coal Field. 143 



regular texture, being sometimes uniform, and at others, conglomerated 

 of clay, and fragmentary masses of iron ore with a calcareous cement. 

 The weathered specimens are commonly of a dark brown color approach- 

 ing to black, and are obviously changed from the character of carbonates 

 of the protoxide, to hydrated peroxides of the metal. As in passing 

 through this change some portions of earthy matter are commonly sepa- 

 rated and washed away, the ore in this latter condition is richer than in 

 its previous state of a carbonate, the loss in carbonic acid and earthy mat- 

 ter being greater than the gain in oxygen and water. This remark will 

 also apply to the other carbonates, as compared with the hydrated parts of 

 the balls or blocks of ore. In the process of decomposition the hydrate 

 is often accumulated in the form of a shell, more or less regular upon the 

 exterior of a nucleus of spongy earthy matter, nearly destitute of iron ; 

 such shells are occasionally found in the bed now under consideration. 

 The following are the results of my examination of this ore. 



" No. 1. A specimen of this ore from near the outcrop was selected, 

 having the elongated kidney form, a shell enclosing white earthy matter, 

 its color in recent fractures of the shell, dark brown. 



" Its specific gravity was 3.2264 at a temperature of 56° Fah. It lost 

 at 320°, 2 y per cent, in water ; and by the application of a white heat for 

 some time, the combined water expelled, amounted to 21.1 per cent. 



" An assay of this ore in the dry way, without any admixture whatever, 

 gave of metallic iron, 32.5 per cent., and of earthy cinder, 29.8 per cent.; 

 oxygen, 14.1 per cent; water, 23.6 per cent.; of which 2.5 per cent., as 

 above stated, was uncombined. 



" The pig metal obtained in this assay was of a light gray color, and 

 rather brittle. This trial proves that the ore will not actually require the 

 use of any flux for its reduction. 



" No. 2. This sample was taken from under the fall, below the lower 

 bed of coal and was in the original state of the mineral not changed to 

 hydrate, as in the preceding example. Its color is light blue, its texture 

 amorphous, or foliated, its fracture irregular ; some shining particles, 

 probably pyritous, are distributed through it. 



" Its specific gravity is 3.0549. At 320° it loses 0.5 per cent. It lo- 

 ses when heated to whiteness, 10.5 per cent, of carbonic acid, with prob- 

 ably a little sulphur. The amount of iron contained in this ore, was 24.2 

 per. cent.; of earthy materials, 49.2. The state in which the iron exists 

 in this ore is doubtless that of a proto-carbonate. The cinder was brittle, 

 of a green color, and perfectly fused. 



" No. 3. This ore was taken from the fifth ply of a bed about 10 feet 

 in thickness, and at an elevation of 1080 feet above the Susquehanna, and 

 64 feet above the 37^ inch bed already described. The ply is 18 inches 

 thick. 



