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NEPTUNE-BANK WORKS.

the turbine. The Parsons air-pump is capable of producing a vacuum of 29 inches. The exhaust-pipe is 36 inches in diameter, a size necessitated by the unusually low pressure of the exhaust-steam. The bearings are of white metal, with forced lubrication. In a recent test of this set, the amount of steam used per kilowatt per hour was found to be 17.8 pounds: a figure which compares most favourably with engines of the reciprocating type. The generator, unlike all the other high-tension machines in the station, has a revolving armature with fixed fields. The collector-rings are insulated from the wooden sleeve which carries them, by means of mica. It has been found that hunting of the synchronous motors at the sub-stations is less pronounced when these are worked from the turbo-alternator than from the reciprocating sets.

Switchboards. On the high-tension switchboards, all the main feeder switches have oil-breaks, and the remainder break in air. The board is furnished with the usual synchronizing gear in duplicate, also wattmeters and ammeters. Below the hightension switches are the field-switches, provided with carbonbreaks; also the hand-wheels for regulating the field-resistances. A subsidiary switchboard is erected in a building on the northern side of the power-house. The main high-tension feeders, which are coupled up to this board, are furnished with spark-gaps, connected across the cores. Their object is to allow a discharge to take place, in the event of the normal voltage being exceeded from any accidental cause.

The low-tension switchboard is provided with three sets of omnibus-bars, one set is in connection with the low-tension network, one set is used for exciting purposes, and the remaining set is used to supply the station lighting and power. In addition to this main board, there are two sets of low-tension panels situated beneath the gallery. These are respectively for the equalizing and starting switches, and for the low-tension meters. Behind the board, are the lighting arresters in connection with the overhead line.

Sub-stations.-There are four principal sub-stations in the Newcastle-upon-Tyne area, in addition to one at Wallsend owned by the Walker and Wallsend Union Gas Company. Besides

these, each of the large manufacturers has a sub-station containing static transformers and high-tension switchgear.

In the Manors sub-station, which is a typical example of these buildings, there are installed two 500 kilowatts motor-generators, one 75 kilowatts induction-motor generator, used for starting the large synchronous sets and one 25 kilowatts balancer. The switches, which are situate in the basement of the building, break in oil, and are so arranged that they can be manipulated from above, thus obviating the necessity of having high-tension connections on the gallery. The high-tension switchboard is furnished with synchronizing lamps and voltmeters, connected to transformers in the usual manner. In addition to the voltmeters and ammeters, there is an indicating kilowatt-meter and a direct-reading power-factor indicator. There are also two induction-meters for measuring the units supplied to the station. All these instruments are connected to transformers placed in the basement. The low-tension switchboard is arranged with the positive and negative panels placed on either side of the central neutral panels. On the back of each set of panels, three omnibusbars are mounted, any one of which can, by means of the plugs and switches in front of the board, be connected to any feeder or generator. Below the low-tension switchboard on the ground level are the field-switches and the main-generator fuse. The sub-stations are all interconnected by special cables, so that any portion of the network can be supplied to any sub-station.

The station at Pandon Dene, which previous to the completion of the transmission line from Wallsend was used as a generatingstation, is now being converted into a sub-station with motorgenerators similar to those in use at the Manors.

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MIDLAND INSTITUTE OF MINING, CIVIL AND
MECHANICAL ENGINEERS.

EXCURSION MEETING,

HELD AT DÜSSELDORF AND IN THE RHENISH WESTPHALIAN COAL-FIELD,
SEPTEMBER 8TH TO 13TH, 1902.

DORTMUND MINING-DISTRICT.

The progress of the coal-industry in Germany is manifested by the following figures:

In the Dortmund mining-district, the rate of increase in the number of persons employed was 47 per cent. during the 5 years, 1895 to 1900, while the increase in the output was 45 per cent., shewing that the increased output was obtained with a proportionate increase in the number of persons employed. In 1900, hewers earned on the average £77 per annum or £1 9s. 7d. per week, while other classes of labour earned about £55 a year or £1 1s. 2d. per week.

The realized prices per ton for the products of the collieries have fluctuated considerably, as follows:

The realized prices are at present much lower than those of

1900.

The compensation paid for accidents averaged as follows:-

DÜSSELDORF EXHIBITION.

The exhibition contained specimens of all descriptions of manufacture and production from the provinces of Rhineland and Westphalia, but was exclusively confined to these provinces, and was in no sense international. The variety and excellence of the exhibits in all departments was extraordinary.

The large model of the Rhenish-Westphalian coal-field (which was mounted upon an elevated platform) consisted of 38 glass-plates, each of which constituted a north-and-south section across the coal-field. The five principal seams (the Hauptflötz, Mausegatt, Sonnenschein, Catharina and Bismark) are shewn, together with the faults and dislocations which have been proved. The shafts are shewn to the depth to which they have been sunk, and the foldings of the seams named are clearly exhibited, thus indicating the coal which remains still to be worked throughout the coal-field. One is greatly struck by the immense quantity of coal lying beneath the level of the deepest shafts, and which probably may never be reached-owing to the

great depth and the high temperature no doubt prevalent at that depth. The overlying marls of the Cretaceous formation, which cover the Coal-measures to the north, are shewn. This model was prepared at the Mining School at Bochum, and is one of the most perfect and interesting models of the kind that has ever been constructed. A map made in 1806 showed that the coalfield, at that time in operation, extended very little to the north of the river Ruhr, which now forms its southern boundary.

The following is a selection of a few of the interesting models. and exhibits contained in the Mining Building:

(1) Complete working model of the Pattberg method of sinking shafts through wet and soft measures.

(2) The Tomson arrangement for drawing large quantities of water by means of large cylindrical tanks, A, was shewn in an excellent model (Fig. 1, Plate XXII.). Two collecting-tanks, B, are employed, suspended at a convenient distance above the sinkers by means of wire-ropes, C and D, which pass over pulleys on the headgear to a capstan-engine. These ropes also act as guide-ropes, a rider, E, being used for guiding the waterbarrels in the shaft. The collecting-tanks, B, are connected together by pipes, and the water is pumped into them by means of a pump, F, attached to the tank by steel channel-bars, G, H. The collecting-tanks are prevented from turning round by means of baulks temporarily fastened in the shaft. The compressedair pipes (for supplying the pump) are carried in the shaft by means of wire-ropes, clamped to the pipes at fixed intervals; and the ventilating air-boxes are carried in a similar manner, the ropes being weighted to keep them taut (Fig. 2, Plate XXII.). The collecting-tanks are 5 feet 7 inches in diameter and 27 feet in length, and the water-barrels are 4 feet 11 inches in diameter and 23 feet long. The water-barrels are drawn by a windingengine in precisely the same way as ordinary coal-work, one barrel ascending while the other is descending. At the bottom of each is a valve. The descending barrel enters the tank and is filled, while the ascending tank is discharged by an automatic arrangement at the same moment. All water produced in the shaft above the tanks is led directly into the tanks, and is not allowed to run into the bottom of the pit. The filling, winding