168 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



[Mat, 



and springs directly from the rocky bed of the river, without any prepared 

 foundation. The smaller arches are of various spans, 46 ft. 10 in., 33 ft., 

 28 ft., and 7 ft. 6 in. The style of construction is somewhat similar to that 

 of the Pont-y-prydd, over the Taff, in South Wales. An engraving of the 

 bridge accompanied the paper. 



" Description of the Mill, Forge, and Furnaces of a Welsh Iron Jl'orlt." 

 By Thomas Girdwood Ilardie, Assoc. Inst. C. E. 



The author commences by describing the general plan of an iron work, 

 consisting of six blast furnaces, four double-fire refineries, and a forge and 

 mill, capable of converting into bar irjn the produce of the sLt blast fur- , 

 naces. lie then enters very fully into certain alterations of the interior 

 shape of the blast furnaces introduced by him at the Blaenavon works, from 

 which have resulted au economy of fuel, regularity of work, and an improved 

 quality of iron. The principal alterations appear to be, making the interior 

 diameter greater above that at the boches, and establishing a proper ratio 

 between the diameter of the boches and that of tlie charging place, and pro- 

 portioning both to the height of the furnace. The opinions are supported 

 by calculations of the quantity of blast used in smelting given quantities of 

 ore, and the eflfect which the form of t!ie fnrnaces must have in directing the 

 current of the blast through the materials, by which also the point of fusion 

 would be necessarily atFected, and the chemical combinations varied. The 

 particulars are then given of the construction of the furnaces at Blaenavon, 

 and the details of the blowing engines, blast mains, regulators, valves, &c., 

 with calculations of the quantity of blast used in the various processes of the 

 manufacture. The construction of the casting houses, with the mode of 

 ventilating by the iron roof, is detailed. The general arrangements of the 

 balance pits, coke yards, mine kilns, and bridge houses, are shown, and the 

 author proceeds to describe the forge and mill, which have 35 puddling fur- 

 naces, with hammers, shears, rolls, and heating furnaces in proportion. He 

 then condemns the usual practice of leaving the coupling boxes loose upon 

 the spindles, as hable to break the rolls, shafts, or machinery, and gives the 

 theoretical and practical reasonings for preferring fixed couplings. The com- 

 munication is illustrated by three drawings, showing all the details of con- 

 struction of the iron works. 



Remarks. — Mr. Lowe believed that there was an incorrectness in the 

 statement of the iron, after being freed from its oxygen by the heat of the 

 furnace, taking up a dose of carbon from the coke, thus becoming a carbtu'et 

 of iron, which is a fusible compound, and as such fell melted into the hearth. 

 On the contrary, he thought that the iron was combined with carbon in the 

 ore, and that there was not any necessity for the medium of the fuel to charge 

 it with carbon. 



Dr. Faraday, in reply to " \Vhy the ore required, or why the iron carried 

 away, any of the carbon of the fuel ?" stated, that the ore being essentially a 

 carbonate of iron, the first action of heat, either in the mine kilns or in the 

 fiirnace, was to draw off the carbonic acid and leave an oxide of iron, and 

 then the further action of the fuel (besides sustaining a high temperature,) 

 was to abstract the oxygen of the oxide, and so to reduce the iron to the me- 

 tallic state, after which a still farther portion of the carbon of the fuel com- 

 bined with the iron, bringing it into the state of easily fusible or pig-iron. 

 As carbon may be communicated to the iron in two ways, distinct in their 

 nature, either by contact with solid carbon, as in the process of cementation 

 (that by which steel is commonly converted), or from the carbonated gases, 

 either carburetted hydrogen, or carbonic acid, which occupy nearly every 

 part of the air-way of the furnace, it would be desirable to distinguish, as 

 far as may be in any furnace having a particular form or action, what pro- 

 portion of the whole effect is due to the one mode of carbonization or the 

 other. 



Mr. Wallace stated that the ore was a carbonate of iron, or a protoxide of 

 iron and carbonic acid united, and not a carburet of iron (or iron and carbon 

 simply), as was generally believed. In smelting, the carbonic acid was driven 

 off, the simple oxide remaining ; the oxygen of which, being carried off by 

 the heat, left the pure iron, which, combining with the carbon of the coke, 

 formed a fusible carburet of iron, or the pig-iron of commerce. 



Mr. John Taylor observed that his brother, Mr. Philip Taylor, being sen- 

 sible of the advantages to be expected from the use of anthracite in smelting 

 iron, made a series of experiments several years ago, from which he derived 

 the opinion that the carbon absorbed by the metal, and which is necessary to 

 produce it in the shape of pig iron, must be presented in a gaseous state to 

 the mass in fusion ; and as anthracite did not afford a sufhcient supply of 

 coal gas during combustion to produce the proper effect, he proposed to 

 adopt a very ingenious method, by which this gas would have been thrown 

 into the furnace in such proportions as might be found necessary, mixed 

 with the common air employed as the blast. Circumstances interrupted the 

 course of these experiments, or it is possible that the use of anthracite for 

 this important application might have taken place at a much earlier period 

 than it has happened to do. 



Fell. 15. — The President in the Chair. 



" Veicription of Chelson Meadow Sluice." 

 Inst. C. E. 



By Theodore Budd, Grad. 



The sluice which is described in this communication was erected from the 

 designs of Mr. Rendel, for the Chelson Marshes in Devonshire, which, being 

 very low, had previously suffered much from floods, but now are entirely 

 relieved. The novelty in the construction consists in hanging each of the 

 doors respectively by two hinged flat bars of iro.,, of 18 ft. 6 in., and 15 ft. 



3 in. in length, and thus, by placing the centre of motion so high above the 

 centre of gravity of the doors, give greater freedom of action than bv the 

 modes usually adopted in similar works. The dimensions of all the parts, 

 and the method of construction, are given in great detail, and arc illustrated 

 by a drawing. 



Remarks. — Mr. Rendel explained that the sluice doors which had been 

 superseded by those described by Mr. Budd, were of the ordinary description, 

 placed side by side. They were frequently hinge-bound and clogged up ; 

 which caused the land to be flooded sometimes for three months during the 

 year ; the hinges were attached in the usual manner to the frames, close at 

 the head of the doors, and they required a pressure of at least 6 inches of 

 water to act upon them either way. He considered the principal advantages 

 of these doors to consist in the freedom of action given by the length of the 

 bar hinges by which they were suspended, their giving the full extent of 

 opening, and the pressure of one inch head of water sufficing either to open 

 or close them. 



Mr. Prior inquired whether there was any similarity between these sluice- 

 doors and that erected by the President near Blackfriars Bridge, at the 

 bottom of Fleet Ditch, That door was so well hung as to be even acted 

 upon by the wind ; and the slightest pressure of water sufficed to open or to 

 close it. 



The President explained that the principle was not the same ; at the Fleet 

 Ditch sluice double hinges were used, or rather hinges with a link betweea 

 the part attached to the frame, and that which was screwed to the door ; — 

 that form of hinge always acted freely, and allowed the doors to open witli 

 a slight pressure. 



" On the mode practised in India for obtaining solid Foundations for 

 Bridges, &;c., in sandy soils, by means of Wells." By Captain Goodwyn, 

 B. E., Assoc. Inst. C. E. 



Piling for the foundation of buildings appears to be entirely unknown ia 

 Hindostan ; the ordinary mode for securing a foundation, where the super- 

 stratum is tenacious and rests upon loose sand, is to dig a well until water is 

 reached ; a curb of timber is then placed, and upon if a cylinder of brick, 7 J 

 feet exterior, and 3^ feet interior diameter, is built to the height of 3 or 4 

 feet above the ground. As soon as the masonry has hardened sufficiently, the 

 well-sinker fixes a plumb-line to the top of the cylinder as a guide, and de- 

 scends withinside, carrying an instrument called a " Phaora, or Mamooti," 

 somewhat similar in shape to a hoe ; with this he excavates the earth until 

 the water is too deep ; he then commences the use of the " Jham," which 

 resembles the " Phaora" in shape, but is about 36 inches long and 27 inches 

 wide, and is suspended to a cord passing over a pulley above the cylinder. 

 Upon this instrument the well-sinker descends, and diving into the water ex- 

 cavates with the " Jham" the soft earth under the sides of the curb, and is 

 at intervals drawn up with the instrument. The cylinder descends gradually 

 from 6 inches to 2^ feet per day, as the earth is withdrawn- from beneath it, 

 and relays of workmen keep it constantly going, lest the sand should settle 

 around it, and cause it to hang up. The natives are very expert in this oper- 

 ation, and not unfrequently remain under water more than a minute at a 

 time. The cylinders have been sunk as deep as 40 feet; but with extreme 

 labour. 



A series of these wells being sunk at intervals of 1 foot between them, 

 they are filled with a grouting of lime and rubble-stone, and separately arched 

 over ; arches are then thrown transversely from the centre of each parallel 

 pair, and another set of arches turned over the adjacent wells longitudinally; 

 the whole is then covered with masonry, and the pier or other building 

 raised upon it : such foundations are found to answer perfectly in situations 

 where almost any other kind would be washed away. 



The communication was accompanied by a drawing of the process, and of 

 the tools used, showing also the modification of the system proposed by 

 Colonel Colvin, of the Bengal engineers, for obtaining foundations for a cur- 

 tain, or line of viall, by sinking square masses of brickwork, with two or more 

 wells in each, through which the workmen could excavate the soil. 



In answer to questions from the President, Captain Goodwyn observed 

 that the greatest peculiarity of this system was that the sinker worked under 

 water ; such had been their custom for ages. Upon this kind of foundation, 

 many of the large fortresses in India were constructed, and they stood re- 

 markably well ; whereas, if timber piles had been used, the white ant would 

 have destroyed tliem in a short time. 



Lieutenant Sale observed that another main reason for not using piles was, 

 that timber was scarce and dear, whereas labour was plentiful and cheap. 

 Hence the general use of the brick cylinders. 



Mr. Parkes conceived the most ingenious parts of the proceeding to be, 

 the sinking through the water, and thus avoiding the risk of bringing up 

 large quantities of sand, and the combination of arches, for distributing the 

 weight of the superstructure equally among the brick shafts. Such shafts 

 had been used by the Chinese, and sunk in the same manner from time im- 

 memorial. 



In answer to a question from the President, Mr. Simpson described the 

 process now so much practised for sinking wells through bad strata liy means 

 of cast-iron cylinders ; excavating the earth from within the cylinder by au 

 instrument called a " miser," which is a conical iron shell with a valve open- 

 ing inwards j it is suspended by iron rods 1^ inch square, and worked from 

 the level of the ground without pumping up the water : it is not uncommon 

 to excavate to a depth exceeding 100 feet in that manner. The " miser" can 

 bring up a cubic yard of earth each time it is raised. Cast iron cylinders are 



