escape for considerable gas. It is a fact that the most gaseous parts of the Lance workings are under the center of the channel southeast of Richard Island; but, on the other hand, the less gaseous parts of the present Five-foot, Hillman, Cooper, and Bennett workings are under an equally thick valley filling. It is stated that the workings of the higher beds in the vicinity of the rock promontory above mentioned were not especially gaseous, but not materially less so than in some districts more deeply covered by the valley filling. There are in the coal measures thick beds of fire clay that appear to be just as impervious as the clay in the valley fillings, and no doubt these are a most important factor in impeding the escape of gas to the surface.

SOUTH WILKES-BARRE MINE.

In Mine No. 5 of the Lehigh & Wilkes-Barre Coal Co. a series of return-air samples was collected to ascertain the relation of certain structural features to the occurrence of methane. The coal measures are here flexed into anticlines and synclines of moderate steepness, most of the dips being from 5° to 45°. There are, however, several local rolls or so-called "faults" in which the dips are steeper. The principal beds worked are the Baltimore, Hillman, Abbott, and Kidney. Owing to the folding, the depths of the beds vary greatly, some of the Hillman workings in the northern part of the mine being more than 1,100 feet below the surface. There is considerable gas throughout the mine, but its volume and manifestations have varied greatly from time to time. The Hillman bed was producing the most gas at the time of sampling, but it was stated that the Baltimore bed, which was not being worked so extensively as formerly, had many very gaseous places and occasional transient blowers.

RETURN-AIR SAMPLES.

In taking samples of return air in this mine the Abbott and Hillman workings were selected because these beds were especially gaseous and the system of ventilation was such that representative samples could be obtained readily. Moreover, the workings extended through areas presenting considerable variation in structure. The samples were analyzed, with the following results.

Results of analyses of samples of return air from Abbott, Hillman, and Stanton workings, South Wilkes-Barre mine.

a Nearly fresh air from No. 3 shaft and Hillman and Kidney gangways; entered Abbott workings through No. 17 tunnel, at the end of which it was split, and ventilated 7 working faces.

Air entered at No. 3 shaft, passed along Kidney and Hillman gangways, then up plane and along No. 11 tunnel into Abbott workings.

c Air passed from No. 3 shaft down No. 4 tunnel, and through 9 working faces at 70 feet below sea level.

The total volume of upcast air of the South Wilkes-Barre mine was sampled at fan No. 1, on shaft No. 5, where it was approximately 315,082 cubic feet a minute. The methane content was 0.72 per cent, or 2,269 cubic feet a minute. This sample represents air from all the workings in the Baltimore and in the higher beds.

AIR SAMPLES FROM THE ABBOTT RETURNS.

The Abbott workings at the South Wilkes-Barre mine are mostly east, north, and south of the shafts. The north workings are in a long, deep basin, in part of which the measures extend somewhat below sea level, or 500 to 600 feet below the surface. The length of the workings in this basin was about 3,600 feet along an east and west line, the easternmost chambers being at Hazel Avenue, a short distance south of Main Street, Wilkes-Barre. The dips in this basin are mostly 6° to 40°, many of them being more than 15°. The surface is covered by a thin body of sand and gravel deposited by the river.

The south workings are in strata which rise gently to the southward, and are about 500 feet below the surface, or 30 to 145 feet above sea level. The surface is hilly and mostly rocky, with a scattered covering of glacial till. The south workings had been extended to a point about 3,600 feet southwest of shaft No. 5. In the Abbott

workings the strata are not broken by true faults, but there are many local rolls in the beds, and in places considerable crushing and shattering, especially in the steeper slopes into the north basin. In general the workings are gaseous, especially in the breasts where coal is freshly exposed. The average thickness of the coal bed is about 6 feet.

The return air from the Abbott workings was sampled at several places so as to compare the amount of methane given off in various districts where depth or structural conditions differ. The air enters at shaft No. 3 and shaft No. 5; the intake from No. 3 entered by airways from other beds and was distributed through tunnels. The principal features are shown in Plate III. Sample 1209 was taken from the return from the extensive southwest workings in the Abbott coal, in all of which the dip of the beds is north at angles, mostly between 10° and 30°, with local variations. The air enters by the No. 5 shaft and at the place where sample 1209 was taken, 300 feet from the shaft upcast, it had a volume of 20,160 cubic feet a minute. As shown in Plate III, 31 faces were being worked, all of them up the dip. The return carried 1.14 per cent methane, or 230 cubic feet a minute. The length of the workings being about 58,600 feet and the height about 6 feet, there was about 351,600 square feet of coal exposed. Therefore 0.65 cubic foot of methane a minute was given off for every 1,000 square feet of coal surface. The average daily output from these workings was 410 tons, so that the methane was at the rate of 808 cubic feet to the ton of coal, a low rate as compared with the amount in most of the Lance workings.

Samples 1208 and 1218 were taken in two airways just north of shaft No. 5, or the main upcast; the samples represented the return air from all the north workings in the Abbott bed. These workings are in the deep, closely compressed basin north of the shafts and extending east as far as Hazel Avenue, Wilkes-Barre. The beds dip into the basin at angles of 8° to 60° and in places are considerably crushed. There were only a few breasts being worked at the time, and these were at the points shown in Plate III. The air enters the mine at No. 3 shaft; part of it goes directly to the Abbott workings and part indirectly through gangways and tunnels in other beds. The volume of the return air of the two airways at the time of sampling was 117,096 cubic feet a minute. The proportion of methane was 0.42 per cent in one airway and 0.44 per cent in the other, indicating a total volume of 501 cubic feet of methane a minute. The length of coal exposed in passageways and chambers in the Abbott workings ventilated by this air was 46,000 feet and as the average height is 6 feet the total area of coal exposed was 276,000 square feet. A calculation from these figures gives 1.8 cubic feet of methane a minute for each 1,000 square feet of coal exposed.