cubic feet per hour of gas at atmospheric pressure, and 50° temperature, the gauge-pressure at the down stream end of pipe being taken at 200 pounds per square-inch.

To change this atmospheric pressure-volume to that of 200 pounds by gauge, Table IX gives the multiplier 14.7, which is now to be used as a divisor. Dividing and we obtain 446,550 cubic feet for the volume per hour at the 200-pound gauge-pressure.

Table VII, in the column under eighteen inches diameter, gives the figure 446,550 in the third line from the bottom, and opposite the figure .272 in the first column.

Then, looking in Table X, opposite the first column figure .272, and in the column for the stated length of line, eighty miles, we find the value 6.094, which is to be multiplied by the 200 pounds gauge pressure plus 14.6 pounds =-214.6 pounds or 214.6 × 6.094 = 1308. pounds, as the fall of pressure for the eighty miles of eighteen-inch pipe-line. Adding the 200 pounds and we obtain the 1,508 pounds gauge pressure for the gas at entrance into the eighty mile-line.

3d example: Pipe-line in two sizes, viz., forty miles of four-inch pipe discharging into twenty miles of six-inch pipe.

Gauge pressure at delivery end of six-inch pipe, thirty pounds; cubic feet discharged 40,000 per hour at atmospheric pressure and temperature of 50° Fahr.

Temperature of flowing gas in the pipes 65°, and specific gravity of

gas, 0.8.

=

Table IX, multiplier 3.055. Dividing 40,000, gives 13,098 cubic feet at thirty pounds pressure and 50° temperature.

=

Table VIII multiplier for 65° temperature of flow and 0.8 specific gravity is .115, and the correction 13,098 X .115 1,470, which we now add, because working backwards relative to application of Table VIII, giving 14,568 cubic feet to be discharged at the lower end of the six-inch. pipe at the gauge pressure thirty pounds and temperature 65° Fahr.

Table VII, under six-inch pipe, the figure 14,568 comes opposite the value .031 in first column.

Table X, under twenty miles, we find just above top figure opposite .031 the value .176. Fall of pressure in the twenty mile six-inch pipe (30 + 14.6) X .176 7.85 pounds.

=

=

Gauge pressure at upper end of six-inch pipe or lower end of four37.85 pounds, and the cubic feet, by aid of Table IX,

inch pipe

=

Table VII, under four-inch pipe, the figure 11,760 comes opposite

the value .222 in the first column.

Table X, opposite .222 and under forty miles, we get 3,560 to multiply into 37.85 to give the fall of pressure in the four-inch pipe, which 135. pounds.

Hence, gauge pressure at entrance into the four-inch pipe = 135 + 37.85 172.85 pounds. Total fall of pressure in both pipes 135. +7.85 =142.85 pounds.

=

=

Acknowledgments are due to B. G. Lamme, a student in the Department of Mechanical Engineering in the State University, for efficient aid in working out most of the tables of this chapter.

CHAPTER X.

THE PITTSBURGH COAL SEAM IN JEFFERSON, BELMONT

AND GUERNSEY COUNTIES.

BY PROFESSOR C. NEWTON BROWN, OHIO STATE UNIVERSITY.

The Pittsburgh coal seam (No. 8 coal of Newberry's scale) is the most important found in the Upper Coal Measures of the state. It lies from 190 feet to 210 feet above the Ames or Crinoidal limestone, and from 80 feet to 100 feet below the Meigs Creek coal, and forms the base of the Upper Coal Measures.

There are two areas in the state where it is mined in a large way, both for local use and shipment by railway and river. The largest and most important of these cover parts of Jefferson, Harrison, Belmont and Guernsey counties. The other covers parts of Athens, Meigs and Gallia counties, where it is known as the Pomeroy coal. Only that portion in Jefferson, Belmont and Guernsey counties is touched in this chapter.

Through this area the coal is remarkable for its regularity in quality, thickness, structure and freedom from wants, clay-veins and horse-backs.

There are usually two partings that divide the seam into three benches. The lower parting-from twelve to fourteen inches from the bottom-is a thin, black slate, sometimes carrying balls of pyrites in it.

The other parting is at, or a little above, the center. It is usually made up of two bands of clay with two to four inches of coal between them, the entire parting being from five to six inches thick. The bearing-in is frequently made at this place.

There is a coal from one to three feet thick, of poor quality, above the main coal and separated from it by about twelve inches of clay. The clay comes down as soon as the main coal is mined out and the thin coal above left for a roof. Above the roof coal is a bed of clay shale. several feet thick, and under the main coal is a thin bed of clay underlaid by a bed of non-fossiliferous limestone.

This coal-field is crossed by five lines of railroad and bounded on

the east by the Ohio River, so that there are ample facilities for putting this coal in any of the northern, western or southern markets.

The coal is used mostly for household fuel, steam generation, gasmaking, and in the manufacture of glass, pottery and iron. Little of it is worked into coke or used for smelting iron.

The facts pertaining to the distribution of this seam are shown in the map that accompanies this volume.

JEFFERSON COUNTY.

Knox Township.-The most northern showing of the Pittsburgh coal, in Jefferson county, is found in Knox township in the high land south of Yellow Creek. At Knoxville, and a short distance northeast in the highest hill-tops towards McCoy's station, are found small areas of the coal. It has a light covering and gives but little good clean coal. The thickness given is about four feet with the usual partings.

Ross Township.-There is a small number of isolated areas of this coal along the south side of Ross township, in Bacon Ridge, between Long Run and Town Fork of Yellow Creek, extending into the northwest corner of Salem township.

Springfield Township.-Near East Springfield the ridge carries several good-sized outliers of coal. The coal here is near the top of the hill. It has been worked for the local trade for a number of years, and is reported as being about four feet thick. The same ridge als extends past East Springfield through the southeast corner of Springfield township, and contains a few small areas of the coal.

Salem Township.-At Richmond, in the eastern part of Salem township, is found a considerable area of the coal. This is a high point from which the water flows into Yellow Creek, Island Creek and Cross Creek. A few mines about Richmond supply the local trade and much of the southern and western parts of the township. In S. W. quarter, section 3, Salem township, the following section was measured:

Above the coal the following section was taken with the barometer:

Just east of Richmond the coal was seen with the same thick bed of limestone over it.

Island Creek Township has the coal in three high ridges in the southwestern part, a few outliers in the northwest corner, and a number of small, unimportant areas in the central part, between Island Creek and north branch of Wills Creek. The coal is usually reported four feet thick, but is sometimes less. The bed of limestone and coal blossom above the No. 8 coal was noticed through this township.

Wayne Township.-None of the Pittsburgh coal is found north of the P., C. & St. L. Ry. in this township, but all the high ridges south of the railroad contain it. It is opened for local use at many points in the township. The coal is reported at from 4 feet 2 inches to 4 feet 10 inches in thickness in the western part. The roof coal is sometimes wanting, but usually the coal with its partings and roof is very regular. In some mines many balls of pyrites are found, while in others they are rare. They can usually be easily separated from the coal. Although Wayne township shows a large area of coal, the proportion of poor crop coal to the good coal is very large; for the coal is so near the tops of the hills and the slopes are so flat that it requires a considerable distance to get under good cover.

Cross Creek Township.-All of this township except the northwest quarter is very well supplied with the Pittsburgh coal. It is high in the hills and seldom has more than 100 feet of cover. It is mined at Wintersville, on the north line of the township, by a shaft about seventy feet deep, which shows the following section:

The bed of limestone and shale above the coal is found throughout the northern part of this township. The Ames limestone is found 4 to 6 feet thick in sections 35 and 36 of this township. It is also fonnd in the eastern part, but is not so well shown. It is by barometer from 200 to