172 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[Mat, 



ELLIPTICAL ECCENTRIC COG WHEELS. 



Sib — Your Southampton corrpspoiident, •' William Davison," is 

 perfectly correct in stating that Elliptical Cog Wheels may be 

 applied with advantage to a variety of purposes, as I have jiracti- 

 cally proved such to be the case, having made and used them in the 

 year 1S40; being considered the first wheels of that shape ever 

 brought under the notice of the publii-. I jtatented their applica- 

 tion to the working of pump rods : the specification of which, is 

 contained in the February number of the Repertury of Patent 

 Invenliotu-, for 184-1 ; published by J. S. Hodson, 1 12, Fleet -street. 

 But their principle of action is more fully treated on, in a publica- 

 tion that ap))eared the same year, intituled ' The Principles of 

 Mechanism.' by Robert AV^illi's, M..A., F.R.S., &c., Jacksonian 

 Professor of Natural ami Experimental Pliilosophy in the Univer- 

 sity of Cambridge; published by .L W. Parker, AV'est Strand, 

 London. If .Mr. Davison takes the trouble of referring to the 

 above work last mentioned, he will find the diagram similar to his 

 own, at page 240. 



Ryde, Is/e of Wight, John Ci. Dashwood. 



April 19, 1850. 



PROGRESS OF THE BIRKENHEAD DOCK WORKS. 



Thk dock works as viewed from the river seem unfinished and 

 ruinous; but ])roceed inland to the western end of the Egerton and 

 Morpeth Docks, and a scene of activity l>ursts upon the view, 

 which it is not easy to parallel. From this point a dam has been 

 carried across to the opposite side of the pool to pen up the waters 

 of the upper portion of the proposed ^xreat float; and here, under 

 the spirited contractor, Mr. M'Cormack, twelve hundred men are 

 working niglit and day, exca\ ating the mud and earth to form a 

 dock which, as at present determined, will e.xtend to the coi)per 

 works on the Seacnnibe side of the pool, and give a water area of 

 fifty acres. A further extension, however, is contemplated, which 

 will carry the dock, or float, as far as Poulton bridge; and tlie con- 

 tracts for this exteusion have been advertised for. 



The depth of this dock adjoining tlie (piays will be eight feet 

 below the level of the old dock sill of Liverpool, or six feet lower 

 than the bed of any of the docks of our ])ort. The centre will 

 not be excavated ([uito so deep. A portion of the walling at 

 the Victoria ^\'llarf, which runs at an angle from the dock ware- 

 houses, is already completed, and is of excellent and solid work- 

 manship. Another portitni. fronting the warehouses, is rapidly 

 advancing. The excavations in the centre of the dock are pro- 

 gressing at a speed which, considering the immense area over 

 which the labour employed is spread, is surprising. Every a])pliance 

 of mechanical skill, and of steam, is, of course, provided by Mr. 

 M'Cormack in aid of the human labour employed. Two steam 

 engines of thirty hoi-se power each lift the wagons of earth from 

 the bed of the dock to the jilace of deposit; and more ai-e being 

 jirovided as the w'orks progress. 



The entranio to the float from the Flgerton Dock is nearly com- 

 pleted, reiiuirini; now only to be smoothed to fit the gates. Those 

 for the inner end of tlie gut are to be seen in the carpenters' shed 

 adjoining the work, and are of immense strength, and splendid 

 workmanshiij. They are, nuireo\er, the largest in the ivorltl, being 

 70 feet wide, and show that the Birkenhead Dock Conimissicuiers 

 have had their eyes open to the fact that we may, in all probability, 

 ha\'e shortly to acconnuodate in the Mersey vessels of much larger 

 tonnage and l)readth of beam than heretofore. The gate next to 

 the float is to be constructed as a caisson, to be moved altogether. 

 and rest, when open, in a recess made in the dock-wall. Tlie main 

 timbers for this work are also prepared, and are formed of pieces 

 of oak, dovetailed and morticed in, so as to increase their strength, 

 and at the same time prevent deflection 



The gut leading to the tunnel, by wbidi the outer entrance to 

 the dock is to be scoured, is also completed, with the exception 

 of a little smoothing of the sill to ensure the fitting of the sluice- 

 gate. The tunnel is fifty feet wide, and alMuit thirty in height, and 

 through it will pass, when the sluice is opened, a large body of the 

 water in the upi)er float, which will be refilled to its proper level 

 by the drainage brought down from Hidston marslies. When it is 

 borne in mind that this is spread over the large area of oO acres, 

 its effect, when compressed, ami flowing through an arch of only JO 

 feet in width, must be to give a most tremendous scouring power. 



PROCEEDINGS OF SCIENTIFIC SOCIETIES. 



INSTITUTION OF CIVIL ENGINEERS. 

 March 26. — William Chbitt, Esq., President, in the Chair. 

 The first paper read was a " Description of the Chappie Viaduct, upon 

 the Colchester and Sloiir Valley Extension of the Eastern Counties RaiUcay." 

 By Mr. P. Uruff, Assoc. Inst. C. E. 



This viaduct was thrown across the valley of the Colne, at Chappie; it 

 consisted of tliinytwo semicircular arches, each of the span of .to feet, 

 the total length being II SG feet, and the extreme hfighl from the founda- 

 tions lo the rail level being 80 feel. The average height of the piers 

 from the foundation to the springing was 4o feet; they were 27 ft. Sin. 

 wide by 4 fi. 101 in. thick, at the under side of the impost, and 

 tapered downwards to the plinth, with a batter of 1 in 36; twenty-three 

 of the piers only had plinths, which, consisted of a set-off of 2J- inches, 

 making the dimensions of the base of the piers 29 ft. in. wide, by 

 7 ft. 1 in. thick. The piers were solid below the plinth, but above that 

 level there was a centre opening 6 feet in width, arched at the top and 

 the bottom, 'i'he whole of this viaduft was constructed of bricks made 

 in the district, bi-ing chiefly set in mortar, but the arches for a distance 

 of 4 ft. 6 in. above the springing were set in cement. The viaduct occu- 

 pied about twenty months in construction, and cost about 55i. per lineal 

 yard. 



The next paper read was " On the Manufacture of Malleable Iron, with 

 the results of Experiments on the Strength of Railway Axles. By Mr. G. 

 B. THORNF.VCROFT, Assoc. Inst. C E. 



It was stated that malleable iron might be divided into two distinct 

 classes, "red short," and "cold short;" the former being generally pro- 

 duced from the rich ores, and the latter from the poorer, or leaner ores. 

 The pig iron made from liie rich ores (under the cold blast process only) 

 was not so fluid as that from the lean ores, but when converted into malle- 

 able ii'on it became tough and tibrous, though it was troublesome to work 

 at less than a while heat, which had caused it to be denominated " red 

 short.'* On the other hand, the pig iron produced from ihe lean ores pos- 

 sessed greater tluidity. but when malleable it was untitled lo support 

 sudden shocks, or continuous strains, and was hence termed "cold short." 

 It was further stated, that in the manufacture of malleable iron very much 

 depended on the quality of the fuel used in the smelting furnace, and ia 

 the subsequent processes; also that iron became crystalline from two 

 causes; first, in consequence of being made from naturally cold short pig 

 iron, and secondly, from a peculiar manipulation during the process of 

 "puddling." 



The introduction of hoi blast for smelting iron, rendered necessary a 

 careful investigation of the coraparalire use of bot and cold blast pig 

 iron, in the manufacture of bars, from which it appeared, that if the same 

 quality of materials was used in both cases, equally good bar iron would be 

 produced, though it was more diSicuIl to convert bot blast pig iron into 

 " No. 1" bars, and the waste was greater. It was certain, thai whilst 

 good grey pig iron could only he produced, by cold blast, from the best 

 materials, iron of apparently excellent quality could be made, by hot blast, 

 from the most sulphurous ores and fuel ; indeed, lo this alone must be 

 attributed the bad reputation of hot blast iron, for certain purposes. 



As it bad been asserted that the peculiar characteristics of malleable 

 iron were lo be attributed to the ore from which it was produced, and not 

 from the different nature of the processes used in its conversion, which 

 the author had always believed to be the true cause, he had, at his works 

 near Wolverliainpton, made bars of the finest crystalline and of the 

 strongest fibrous texture from the same Yorkshire pig iron, .\nother 

 cause which induced great changes in the texture of iron, when cold, was 

 compression, or impact, whiub would completely alter its texture from a 

 fibrous 10 a crystalluie character, as was well exemplified by the "gag*' 

 and the puddling tools used by forgemen, and in several parts of different 

 kinds of machinery the same effect was observed. 



The author Iben proceeded to draw attention to the best shape for rail- 

 way axles, so as to combine tlie greatest strength with the least material, 

 illustrating his views by the details of a series of experiments made for 

 determining the question. It would appear that railway axles should be 

 made parallel, from journal to journal, without any shoulder, and with just 

 sufficient strength to jirevcnt any vibration in rotating. The csperinieats 

 showed, that an axle without a shcmlder was better able to resist impact 

 than one with a shoulder, in the ratio of 155 to 55, and by leaving the 

 axle parallel, its stieuglh, compared wilh the same sized axle reduced in 

 the middle, was 5 to 1^. 



April 2. — In the renewed discussion upon Mr. Thorneycrofts paper, it 

 appeared to be admitted, that the shoulder on axles was only useful as a 

 gauge, and that it should be curved from, and not square to, the main 

 body; — that between the journals the axle should be parallel, for if reduced 

 in the centre it was sure to bend, and eventually to break. Since the last 

 meeting Mr. Tborneycroft had made many other experiments, which proved 

 his former opinion relative to the progressive changes in iron, from compres- 

 sion, which alone caused the destruction of the fibre, and, in fact, that 

 jarring would not do it. Experiments were suggested to ascertain whether 



