During the passage of the gas through these pipes an additional quantity of tar and aqueous products are condensed, and fall into the rectangular boxes, which are all placed in connection by connection-pipes, and from whence they continually flow into the tank before mentioned.

From the condensers the gas passes through 8 scrubbers, each 20 feet high, and placed in four rows. Each scrubber has three layers of stones resting upon gratings, and is provided with a mill and tumbler, by which a dense rain is made to fall through the scrubber, so as to wash the gas and remove as much of the tar and other condensible products, especially naphtha, as possible. From the scrubbers the gas passes into a kind of drum or main, called the trunk, 25 feet 3 inches long, and 3 feet 8 inches in diameter, which serves as a valve, and whence the gas is conducted to the several fire-beds by means of iron pipes, or brick sewers well lined with cement.

Plates I. and II. represent the plan, elevation, and section of these arrangements on a scale of one inch to 5 feet. The letters on both plates represent the same objects. A is one of the furnaces, shewn in elevation, (plate I,) B is the hopper, the covers of which, also marked B, are shewn in fig. 1, plate II, with the two lids H, provided with hinges and flanges which fit into grooves. Fig 2, plate II, represents a section of the furnace along the line x, plate I; a represents the arrangement of the tuyeres with their nozzles, showing the water spaces and the plug valves for allowing the tuyere openings to be kept clear, B is the hopper, and c the conical valve with its grooved rim, into which fits a circular flange surrounding the valve opening. The valve b may be raised or lowered by means of the rod and chain c attached to the lever d, having a sort of box on one end, into which fits a number of small cast iron plates forming the counterpoise e.

C, fig. 1, plate II, represents the platform on the top of the four furnaces, formed of planks of wood laid in the same plane as the covers of the hoppers. The turf is elevated to this platform in iron waggons, each of 30 cubic feet capacity, by means of a water-lift, consisting of a floor upon which four waggons fit, supported by a frame work or cage, with friction pulleys at the angles, which work against four upright pillars of wood, which support a frame work at top, having a drum and brake. The flooring or cage is attached to a chain which passes over the abovementioned drum, and is counterpoised by a wrought iron cistern, 5 feet square, and 2 feet 6 inches deep, provided with a valve in the bottom with an externally projecting spindle.

The peat is brought from the bog in flat bottom boats by means of a canal, which terminates in a kind of basin, having a quay a few yards wide at the foot of the lift. Upon this quay the waggons are filled with turf, which are then rolled in upon the floor of the cage, which is let down to the level of the quay. In this position of the cage the counterpoise or iron cistern is at top; into this water is allowed to flow from the tank I, (fig 1, plate II,) which is supplied by the feed pipe, J, in connection with a large pump worked by a steam engine, which also works all the other pumps connected with the other arrangements of the works. When the cistern is full it more than counterbalances the cage and waggons, and

accordingly, on letting go the brake the cistern descends, and by means of the chain passing over the drum, drags up the cage and waggons to the level of the platform, G. When the cistern full of water reaches the ground, the projecting pin strikes against the ground, by which the valve is lifted and the water allowed to flow out.

The waggons full of turf thus lifted up to the level of the platform are rolled along tram ways at each side of the hoppers, the end of one of which is marked N, to the furnace into which the turf is to be put. At each side of the cover of each hopper is a turning table M; the waggon being brought upon this table, it is made to describe a quarter revolution, so as to bring the end of the waggon, which is provided with a hinge and latch, over one of the hopper lids H, which is then lifted, and the contents of the waggon discharged into the hopper, by lifting the waggon which is attached by only one of its ends to a truck. Three waggons full of turf or 90 cubic feet constitute a charge, that is to say, fill the hopper.

During the operation of filling the hopper, the conical valve b is, of course, closed, as it is represented in fig 2, plate II, and no gas or other products of distillation can, escape through the hopper. As soon, however, as the hopper is filled, the lids H, fig 1, are closed, the groove into which the lid flange fits being first partially filled with a mixture of turf dust and some of the blue clay marl underlying the peat bog, mixed up into a paste with water. This paste forms an excellent lute around the lid, which is kept tight by a latch. The valve b (fig 2, plate II.) may now be lowered by means of the lever a, which, while the valve is up, has its end bearing the counterpoise e hooked to the platform by means of the small hole which is seen near the counterpoise; in this way the valve is kept pressed against the flange around the valve opening. As soon as the valve is let down, the turf falls into the body of the furnace, whereupon it is again lifted, and the hopper may be recharged.

The only loss of gas sustained by the arrangement is simply the full of the hopper each time the furnace receives a charge. When light peat is burned each charge weighs no more than 7 cwt., so that it would require about 143 charges to burn 50 tons, and 286 to burn 100 tons, the latter being the quantity which the furnaces were calculated to burn in the twenty-four hours. Supposing 100 cubic feet of gas to be lost by each charge, the maximum loss of gas and products in twenty-four hours would only be 28,600 cubic feet. As the average good brown turf would weigh, per charge of 90 cubic feet, about a half ton, it would only take 200 charges in the 24 hours. Supposing the furnace to consume 100 tons in that time, the loss of gas from this source would only amount to 20,000 cubic feet, a quantity compared to the total quantity produced very insignificant indeed.

The mode of closing down blast furnaces just described is perhaps the most perfect ever adopted, and is equally applicable to the ordinary charcoal, or coke, or coal high furnaces as to the peat furnaces just described. The fuel, ore, and flux, may be introduced into such a hopper with the greatest facility, and the whole of the gases thus economised, and applied to the puddling, refining, &c., of iron. In this point of view alone, and

without reference to the special application of which we are treating, this method is of paramount importance at the present moment to the iron trade of the whole world.

As this method is but the last of a number of successive improvements which have been effected in different countries and by different persons, it may not be uninteresting to our readers to trace the progress of these improvements.

The first mode of economising the waste gases of furnaces was that of Faber du Faur, who placed a ring of flues all round the inside of the furnace, at about one-third of the height of the body from the top. These flues passed upwards through the brick work, and the hot gases were then conducted away by a descending pipe to the points where they were required. This method had the disadvantage of drawing off not merely the waste gases, but even the actual flame, so that a large portion of the heat was wasted; and when used in heating the blast, or for similar purposes, the heat produced was so excessive that the apparatus was often burned through. Mr. James Palmer Budd, of Ystal-y-Fera, in Wales, to whom the honour belongs of having first attempted to utilize the waste gases in Great Britain, modified the method of Du Faur, by tapping the gases at a part only three feet below the throat of the furnace. As the same quantity of the gases would not enter flues at that point as lower down, and as they would get mixed with air, Mr. Budd, by making an upright flue, 25 feet higher than the platforms of his furnaces, and provided at top with a kind of damper, was enabled to suck, as it were, any quantity of the hot gases, and make them pass under boilers and heat the blast, &c., before finally passing off through a high chimney. It is unnecessary to remark, that in Mr. Budd's arrangement for heating the hot blast, the gases were not burned, except in the case of the steam boilers, under which we believe the gas was burned; it was only the high temperature at which they issued from the furnace that was taken advantage of.

The next modification worthy of notice is the mode in use at the Dundyvan Works, in Scotland. The furnace is 42 feet high, and is 12 feet in diameter at 8 feet from the top; from this point it Larrows to 8 feet at the filling place. Just below the point at which the narrowing commences is a ring of 8 flues, 4 feet high and 18 inches in diameter, all of which open into an annular flue surrounding the top of the furnace, from near the top of which the gas is conducted away. A similar plan is adopted at Pontypool, the width of the furnace in this case, below the ring of flues, being 13 feet, and narrowing to 9 feet 6 inches.

Another plan, and one indeed adopted at a very early period, was to introduce a cylinder somewhat smaller in diameter than the throat of the furnace, and open at both ends, into it, and having a projecting flange on its upper end, which rests on the top of the furnace. There was formed an annular chamber, in which the gas collected, and into which the flues or ports opened. By keeping the central cylinder full of fuel and ore, a certain resistance was offered to the passage of the gas, which accordingly passed off by the flues in the inclosed space. This plan, which was first employed on the Continent, has also been tried in Great Britain, and

1854.] Products of the Destructive Distillation of Peat.

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among other places we believe at Dundyvan, in connection with the system of flues just described.

In all the preceding cases only a portion of the gases was economised, whilst the rest escaped into the air. To utilize the whole it would obviously be necessary to completely close the furnace, and accordingly one of the earliest attempts was that made at the great iron works of Le Creusot, in France. This method, which is, we believe, still used in seven furnaces there, is represented in fig. 1. C is a conical iron cylinder, which

has exactly the same inclination as the walls of the furnace, S, and therefore as it were a continuation of it. Just below the cylinder, C, the wall of the furnace is beveled off for a short distance, and then goes up parallel with the cylinder, C, forming an annular space exactly like that described above. D is a double cover, hinged on at s, and which may be lifted by means of the lever, h, with the counterpoise, g. This cover has a flange all round it, seen at d d, which fits into an annular box or groove, in which water or sand may be put to form a tight joint. The gas, as it ascends, passes into the annular space around C, from which it is carried off by the gas duct, R, having a throttle valve, v, for regulating its supply as may be required. Independent of the fact that by this plan the furnace can be completely closed down, the cylinder, C, being in a line with the walls of the body of the furnace, S, allows the charge to descend with the same regularity as if the furnace were open; whilst with the cylinder before described, the materials went too much towards the centre, which is a great evil, as it is of great importance to have a column of blast in the centre of the furnace, while the ore and flux should lie towards the sides.

This last object is still more perfectly attained in the next modification of importance with which we are acquainted. This plan, which is represented in fig. 2, was, we believe, first adopted by Mr. Levick, of the Cwm

Celyn Works, near Abergavenny, in Wales, and a model of it was exhibited at the Great Exhibition of 1851, in connection, if we recollect aright, with a model of a blast furnace contributed by Mr. John James, of Blaina Works, which belong to Messrs. Crutwell, Allies, & Co., who are also the proprietors of the Cwm Celyn Works. The upper part of the body of the furnace, for a distance of about 5 feet below the mouth, M, is cylindrical. At the junction of this cylindrical part with the conical body, S, is a double cross, a, formed of iron bars let into the masonry; upon the centre of this cross is placed the cast iron cone, A, the apex of which is in the axis of the furnace, and whose base is about 2 feet all around from the wall of the furnace. Upon the same cross bars rests the hollow annular cast iron cylinder, B, open at its lower end, which diminishes the mouth of the furnace, m n, to the space, o p. The lower edge, q r, of the inner wall of the cylinder, B, is about 1 feet from the base of the cone, A, so that an opening of 18 inches wide exists all around the cone into the body of the furnace. This opening can be closed by means of the cylinder, C, open at both ends, which fits on the inner wall of the cylinder, B, like the tubes of a telescope, and may be drawn up or let down by the rods, k h. When the cylinder, C, is let down upon the cone, A, the furnace is completely closed, and the whole of the gas will pass off by the duct, D. If in this case the internal cylindrical space over the cone is filled with fuel, ore, and flux, and the cylinder, C, be lifted to the level of the dotted line, G, the whole charge will fall into the furnace, and under the best conditions, for the central column of blast will remain undisturbed. The duct, D, can be closed, in case it may require closing, by the damper, d; in such case, the pipe, b, which is closed by a cap, admits of the escape of the gases. By this plan all the gases could be economised, except merely what passed off while the charge was being allowed to fall into the furnace.