had had little or no trouble with stone-work, where lime or cement was used, excepting that the cement was apt to crumble out in damp portions that were exposed to the action of very cold weather-this. however, had not affected the walls very seriously. He would not think of using either lime or cement-mortar in connection with the brickwork of the oven itself.

As Mr. Greener anticipated, they did not draw the ovens solidly but alternately, having in view the advantages to be derived from the proximity of a hot oven. He (Mr. Keighley) realized that there is a great waste of gases under the present practice, but the Connellsville coke-region is not yet in a position to take up the bye-product question. The larries are so arranged that the coal runs from either side, as may be desired.

He had experienced no great difficulty in burning either 24, 48, 72 or 96 hours coke; but, the very best results were obtained from the 48 hours burning. He had made thousands of tons of 24 hours coke in one month; and found no difference in the quality of the coke, excepting that it was much shorter in length than the longer burnings produced; but it would be well to say in that connection that the success in making 24 hours coke depends largely upon quick work.

He (Mr. Keighley) took no stock in the theory (which Mr. Greener quoted and also deprecated) that in order to obtain coke in the best possible mechanical condition, it should be allowed, as coke-burners describe it, "to soak in the oven" for 6 or 7 hours after it was burnt off.* He found, by actual experiment, that the standing over of a charge after it had been burnt off resulted in loss or wasting of the coke-a period of 10 hours showing a loss of 5 per cent. in weight. In the matter of breeze, which in their practice amounted to about 3 per cent., he might state that this was due largely to the large spaced coke-fork used in the Connellsville region, the space between the tines being 11⁄2 inches. Forks had been tried with inch tines, but the coke-consumer objected to the increased quantity of small coke resulting therefrom.

As everything in the way of drawing and loading was done by hand, no great reduction in the cost of production could be expected, even in new plants. The cost of labour in the Connellsville coke-region was continually on the increase, and no reduction in labour-costs could be obtained without the introduction of * Trans. Inst. M.E., 1902, vol. xxiii., page 488.

!

machinery in the drawing and loading operations, and this, so far as relates to the Connellsville coke-region, was still in an experimental stage.

The great thickness of the seam admitted of comparatively cheap mining; yet this cost was also on the increase, as that work was also hand-work, and so far machines had not been successful in the Connellsville seam.

Mr. T. E. FORSTER read the following paper on the "Under

sea Coal of the Northumberland Coast":

UNDERSEA COAL OF THE NORTHUMBERLAND
COAST.

BY T. E. FORSTER.

Introduction.--The Northumberland coal-field extends along the southern portion of the Northumberland coast, from the Coquet to the Tyne, a distance of about 24 miles (Fig. 1, Plate X.).

Roughly speaking, the direction of the general dip of the measures is a little to the south of east, the line of outcrop commencing on the north at the mouth of the river Coquet, and running thence south-west by south.

This direction of the dip may be said to continue over the whole of the field, until a line is reached, eastward of which the beds commence to rise in a south-easterly direction. The course of this syncline is north by east, and nearly at right angles to the direction of the general line of dip. The northern end of the syncline passes under the sea near the river Wansbeck, and the southern end runs beyond the river Tyne, into the county of Durham, between Wallsend and Walker.

The average rate of dip is very moderate, and the field is not troubled by heavy faulting. With the exception of two large faults near the mouth of the river Coquet, the Wansbeck fault, and the ninety-fathoms dyke at the southern end of the field, near the river Tyne, all with an east-and-west course, there are no faults of unusual magnitude.

Coal-seams. The upper series of seams, which have been chiefly worked in the eastern portion of the field, along the seaboard, are, the High Main, Grey or Main Coal, Yard Seam and Low Main. The lower seams, consisting of the Beaumont, Busty and Brockwell, have only been opened up to a limited extent, but will doubtless come into working on a much more extended scale as they are required. The vertical distance from the High Main to the Brockwell seam is about 750 feet.

VOL. XXIV.-1902 1903.

28

The extreme northern part of the field, in the vicinity of the river Coquet, appears to be occupied chiefly by the lower seams, but it has never yet been possible to correlate them exactly with the seams of the district to the south. Between the two portions of the field, there is a belt of ground, the exploration of which has not so far yielded satisfactory results. Such proofs as have been made, point to alterations in the character, not only of the coal-seams, but also of the beds associated with them, and the fact that the lower seams near the Coquet bear no resemblance to those occupying the ground to the south, forms a barrier to their complete identification, which will probably never be entirely removed.

The principal seams of the Coquet district are:-The Radcliffe, Albert, Queen, Princess, Duke and Yard seams, which are found in a vertical distance of about 400 feet. The Radcliffe seam is supposed by some to be the Low Main, and the Princess, the Beaumont of the Blyth and Tyne district, but, apparently, this is a mere speculation.

The following is a brief description of the conditions under which the various seams exist along the coast-line. Commencing at the mouth of the river Tyne, and passing northward, to Seaton Sluice, the measures, owing to the synclinal axis above mentioned, have a south-easterly or seaward rise; and, consequently, the upper seams crop out practically along the coast-line. The lower seams have never been worked in this vicinity, but probably extend seaward for some distance under a workable thickness of cover. The trend of the coast, passing northward, is to the west of north; and, consequently, the synclinal axis approaches the shore-line and the seams along it assume a heavier cover. The section (Fig. 2, Plate X.), from Hartley, past Seaton Sluice and Blyth, through Newbiggin and northward to the mouth of the river Lyne, is intended to shew approximately the position of the beds along this section of the coast.

Along the southern part of the line, the cover is gradually increasing, as the line of the section approaches nearer to the synclinal axis, the Low Main, off the mouth of the river Blyth, lying at a depth of about 400 feet below sea-level, 600 feet at Cambois, with a further dip of about 150 feet to Newbiggin bay, where the large downthrow-fault to the north, known as the Wansbeck fault, is found. North of this the beds rise very rapidly, until

they pass beyond the region of the fold caused by the fault, and regain their normal level and rate of dip. Beyond the Wansbeck fault, they are, however, unexplored along the coast-line, and that portion of the section is compiled from such information as can be got from data obtained slightly further inland. The belt of doubtful ground described above, commences north of the river Lyne, passes Cresswell and stretches into Druridge bay.

Half-way up Druridge bay, at the mouth of the Chibburn, the Coquet district of the coal-field may be said to commence with the southern limit of the workings of Broomhill colliery, abutting on an east-and-west fault. Beyond this, the seams lie regularly for a considerable distance along the shore-line, with a gentle inclination to the east, until they come within the line of influence of the first of the two great faults previously mentioned, towards which they dip heavily. This fault is computed to throw up the beds, 480 feet, to the north; and the second fault (met with about mile farther on) has a throw of about 600 feet in the same direction. Beyond this, the beds rise to their natural outcrop north of the mouth of the river Coquet.

Coast-line.

So far as surface-features go, the coast-line consists of a series of rocky points, alternating with long bays, the shores of which are occupied by hills of blown sand, capping the Boulder-clay, which, generally speaking, covers the whole of the low-lying flat-country in the immediate neighbourhood of the

coast.

The promontories usually mark the lines of east-and-west faults, against which the clay generally attains its greatest thickness, thinning gradually in the direction of the rise of the underlying measures (Fig. 2, Plate X.).

At Cambois pit, the clay is upwards of 80 feet thick, gradually decreasing southward to North Blyth rocks, and re-appearing on the southern side of the river, where it lies, about 60 feet in depth, against the cheek of the fault, which forms the northern side of the entrance-channel to Blyth Harbour and thinning again along Blyth Bay to Seaton Sluice.

The bed of the sea may be described as shelving gradually eastward. The different submarine contour-lines have a regular and uniform course: the variations in their distance from the shore, being due almost entirely to irregularities in the coastline.