Exhibiting Its Relations To The Principal Mar Engineer Of Mixes. etc.

They arc generally made from picked specimens, by many men and many methods, each giving widely diverse results even from the same coal, and the mere aggregates of carbon, volatile matter, and ash, while the distinguishing features and chemical constituents are seldom given. The change from anthracite to semi-anthracite is gradual and imperceptible in the coal beds of the prominent anthracite fields. There is no fixed point at which the one terminates or the other commences. The same uncertainty is manifest in all published analyses of mineral coal. No commonly adopted limit is assigned to the various gradations. Those called semi-anthracite in one place are termed anthracite in others, and vice versa. The same indefinite relations are observable between semi-anthracite and semi-bituminous, and between semi-bituminous and bituminous coals; while the gradations of all carbon compounds are alike indefinite and unsettled, down through cannel coal, bitumen, asphaltum, petroleum, naphtha, and carburetted hydrogen gases. The uncertainty, however, exists in the mean and not the extreme varieties. Hard, dense anthracite could not be mistaken for any other class; and while light, volatile semi-anthracite might be readily termed semi-bituminous, it could not be mistaken for anthracite.

The following table gives the average aggregate constituents of the prominent varieties from the chief anthracite districts of the world:

Analyses Of Anthracite

LOCALITY.

By whom analyzed.

Nomenclature.

Carbon.

Volatile matter.

Ashes.

Density.

Color of ashes.

No.

0.

Lackawanna. Carbondale...................

Rogers' Reports...........

E

90.23

7.07

2.70

1.400

White.

"

1.

Lehigh District, Mauch Chunk.............

Olmsted..........

E

90.10

6.60

3.30

1.550

"

"

2

" " " .........................

Dr. J. Percy......

E

92.60

5.15

2.25

1.558

"

"

3.

" " Beaver Meadow...........

Johnson..........

E

92.30

6.42

1.28

1.630

"

"

4.

Pottsville District, Tamaqua...............

Rogers' Reports...

E

92.07

5.03

2.90

1.570

"

"

5.

" Delaware mines, mean of 40 varieties

Johnson..........

M

86.09

6.96

6.95

1.460

Red.

"

6.

" Mammoth coal bed.................

Roers' Reports..

E

94.10

1.40

4.50

1.500

White.

"

7.

West'n Dist.. Lykens Valley, semi-anthracite

M. C. Lea...................

B

85.70

10.00

4.30

1.416

Red.

"

8.

" " Dauphin, semi-bituminous..................

Johnson..........

?

76.10

16.90

7.00

1.350

?

"

9.

Virginia, Price's Mountain.................

A. H. Everett....

B?

89.25

2.44 water.

8.30

1.370

Pink.

"

10.

Rhode Island, Portsmouth.................

Dr. C. T. Jackson.

?

85.84

10.50

3.66

1.850

?

"

11.

Massachusetts. Mansfield..................

"

?

87.40

6.20

6.40

1.690

?

"

12.

South Wales, hard anthracite..............

De Schaufhauelt..

?

9242

5.97

? 1.60

?

?

"

13.

" " semi-anthracite..............

Taylor...........

?

86.24

12.00

1.76

?

?

"

14.

French. Mavence.......................

Dr. A. Fyfe.......

?

90.72

8.34

? .94

?

?

"

15.

Jurassic, Lamure...........................................................

M. V. Regnault...........

?

88.54

6.89

4.57

1.370

?

"

16.

Russia. Donetz......................

M. Voskressensky.

?

94.234

?

?

?

?

"

" Titlis..............................................................................................

"

?

63.694

?

?

?

?

"

New Mexico. Santa Fe, lignitic anthracite..

Henry M. Smith..

?

74.372

19.576

6.052

?

Pink.

"

Sonora, Les Brouces, " "

"

?

84.103

8.693

7.204

?

Gray.

The above table is compiled from the best available sources; and though the analyses are generally from hand specimens, and therefore not commercially useful, they are characteristic, and indicate the chief constituents of the prominent anthracites. - The anthracites of Pennsylvania are generally denominated white-ash or red-ash coals, but the color of the incombustible residue varies from pure white to gray, rose-pink, pink, light-red, brick-red, and brown; and this variation of color is as marked in the ash of bituminous and all intermediate varieties of coal as in anthracite. The color of the ash is obtained from the oxide of iron, and is no criterion of the character or value of the coal, because these colors exist, from white to brown, in the lowest, oldest, and hardest anthracite, as well as in the upper, latest, softest, and most volatile semi-anthracite and bituminous coals. - The nomenclature proposed by Prof. J. P. Lesley and adopted in " Coal, Iron, and Oil," the latest standard work on anthracite, in which the beds are identified in the Pennsylvania anthracite fields and connected with the bituminous coal beds of the Alleghany field, designates the lowest workable and consistent bed as A and the highest as X. But this nomenclature denotes series or groups of coal beds, rather than single beds.

Fig. 1 presents the general type of the Pennsylvania anthracite strata. The figures in the column and in connection with the letters indicate thickness in feet. A number of small unworkable seams are not here represented. The 15 groups from A to N include 30 beds above 2 ft. thick and 20 seams less than 2 ft. This mode of grouping the beds in the anthracite fields was suggested by the natural divisions of massive sandstone and conglomerate strata in the coal measures, and the frequency with which some of the prominent groups united as a single bed or divided into two or three beds. In the southern anthracite field of Pennsylvania a few imperfect, irregular, and impure "nests" or pockets, rather than beds, of graphitic anthracite are occasionally found below A; but these local deposits have no general horizon, and are valueless for commercial purposes. Though pockets of good coal are sometimes found from 5 to 20 ft. thick, they vary to as many inches, and do not exist as regular and consistent beds. A is usually a small bed of red-ash coal, but two or three thin seams are frequently found in this group which exist in the conglomerate, or close to it, everywhere. The coals of A generally contain from 10 to 20 per cent. of earthy matter, and are seldom workable.

B is generally a large bed from 10 to 80 ft. thick, but frequently two beds of 5 to 10 ft. each. The lower part produces red-ash coal, and the upper gray or pink. The coal is excellent, and valued for blast furnances, though it contains more silica than the coal of any other workable bed higher in the measures. C is usually a group of small unworkable beds, producing white or gray-ash coals. 1) is a single bed of pure white-ash coal, generally from 5 to 10 ft. thick. E is the celebrated mammoth, which is a single bed from 20 to 70 ft. thick in some localities, and a group of two and three in others. The coal is always of the white-ash variety, and is hard, dense, pure, and lustrous. Fully eight tenths of the present anthracite production is from this group. F is composed of two small beds of white-ash coal, and is not of much value; it is often known as the "rough vein." G is generally a large bed from 7 to 10 ft. thick, and always a single one, though the lower stratum produces white-ash and the upper pink or gray-ash. It is locally known as the gray-ash or primrose vein, and is supposed to be identical with the Pittsburgh bed in the bituminous field.

All the workable beds, from A to G inclusive, produce blast furnace coal; but the coals of the beds from G to N are less dense and contain less carbon and more volatile matter than the lower coals, and crumble under a high temperature. They are therefore not used for steam and furnace purposes generally, but are much valued for household uses, excepting large furnace heaters. They evolve an intense heat, and are free-burning, but will often "clinker" under a strong draught. In the preceding analytical table the highest percentage of carbon is 94.10 (No. 6), which is a hand specimen from the mammoth bed, E, in the Pottsville district; but it is a well known fact that the mammoth coals of the Lehigh district are equally as pure and generally more dense than any other anthracite. The average, therefore, of Nos. 1, 2, 3, 4, and 6 will give the mean of the hardest and purest anthracite; while No. 5 (M) is a type of the upper coals, and approaches the limit of the true anthracite, as shown by 7 and 8, which are semi-anthracite and semi-bituminous. The density and hardness of the coal decrease from A to N in the ascending order, while the volatile matter increases from N to A in the descending order; and the proportions of carbon increase and decrease in the same ratio and order.