1845.] 



THE CIVIL ENGINEER AND ARCHITECTS JOURNAL. 



S3 



driver, tliat part of the a|)paratiis touUI lie suppressed, and tlie switches 

 coidd be woikcd by baiiil from the side of llic railway as at present j but 

 Mr. Faram stated that system to be less useful and ccrtaiuthaii Ids plan. 



March 11). — The TuKsiuiiNT in the Chair. 

 Formation of thk Town L.vnds ok Mussei-burgh. 



" DencriptioH of the furmatiim of the Toivn-lamU of Muuetburgh, on the 

 firth of Forth." Uy Jamks IIav. 



The autlior states, that the delta of low alluvial land at the mouth of the 

 river lisk, whieh eouiprehends Ihc town-lauds of Miisselburgli, to the extent 

 of at least -100 aeies had been gained from the sea, in the space of about 

 three hundred years, by the gradual operations of nature, unassisted by art. 

 If an excavation be made to the depth of a few feet, in ground that has not 

 been [ireviously disturbed, gravel and a few shells are found, the latter not 

 fossilised, but iu the same state in which they are found upon the beach at 

 this time; and in cutting a drain to a depth of 7 feet in this deposit, at a 

 quarter of a mile from the sea, the author found a piece of wrought-iron, 

 which was surrounded by a concretion of shells and gravel, clearly proving 

 that the sea had recently been there. He also mentions several facts, from 

 ancient charters and leases, showing that the spot, where the present town- 

 lands of Musselburgh exist, must formerly have been beneath the level of 

 the sea. The causes which eonliibutc towards producing these changes are, 

 that the river lisk, when swollen by rain, brings down with its floods, the 

 detritus of the hills through which it passes, which, with the soil washed 

 from the banks of the low-lands, is arrested, when it meets the tide, and is 

 thrown on the beach; then, by the action of the high north winds, the sand 

 is carried up from the gravel, anil raises the land several feel above the level 

 of the sea, and iu some places as much as 12 feet. Another cause is, tliat 

 along the I'irth of Forth, and particularly between Leith and Newhaven, the 

 sea has made great encroachments, and about a mile west of Musselburgh 

 many acres of land have been swept away, the lighter portions of which, arc 

 carried eastward by a current setting in that direction, and are lodged near 

 the mouth of the Esk. 



lIvDRAULic Traversing Machine. 

 " Description of the Hydraulic Traversinij Frame, at the Bristol Terminus 



of the Great Western Railwarj." By Arthur John Dodson, Assoc. 



lust. C. E. 



The object of this machine is to transport the railway carriages, from tlie 

 arrival side of Ihe terminus, to the departure side, or to any one of the 

 several intermediate lines, without the use of tuiu-tables, which cannot 

 always be conveniently or safely introduced, and also without any intersec- 

 tion or derangement of the rails. The apparatus consists of a wrought-iron 

 frame, connected by cross and diagonal pieces, and supported upon eight 

 cast-iron wheels. At the four corucrs of the frame, cast-iron hydraulic 

 presses are tixed, and at one end of it, two force-pumps are placed, con- 

 nected with the presses by copper pipes and gnn-metal nozzles. Upon the 

 wrought-iron plungers of the four presses, two additonal frames rest ; these 

 arc attacbed to the lower frame, by four sets of parallel-motion bars, to 

 ensure their rising perpendicularly. The action of the machine is described 

 as follows : — An opening being made in the train, the apparatus is pushed on 

 to the line of rails, and the carriage required to be moved is placed over it 

 when the frame is quite down. As soon as the carriage is brought directly 

 over the apparatus, a man works the larger pump acting upon the four 

 hydraulic pres>es, which raises the frames until they are in contact with the 

 axles of the carriage wheels ; the smaller pump is then worked, until the 

 flanges of the carriage wheels are clear of the rails. The whole apparatus, 

 with the carriage suspended upon it, is then easily transported to any of the 

 lines of rails, and by unscrewing the stopper, which allows the water to flow 

 back from the presses into the cistern, the carriage is lowered on to the 

 rails ; it is then pushed back, and the apparatui is rolled over, ready for re- 

 commencing the operation, the whole transit not having occupied more than 

 a minute and a half. 



Mr. Dodson stated, in answer to questions from the President, that this 

 hydraulic traversing frame had cost about 220/. : that it was the only one of 

 the kind al present in use on the Great Western Uailway, but that in con- 

 sequence of its action being so much approved, several others were expected 

 to be erected. 



Mr. Brunei said, that the macldne in qneslion was made by Mr. A. Napier, 

 of Lambeth ; it was extremely well constructed, and he intended using others 

 of the same kind. He expected they would be less expensive than the one 

 described, which was the first that had been made. 



Land Sup in the Ashlev Cutting. 



'■ Account of the Land-Slip in Ashley Cutting, on the line of the Great 



IVi'slern Railway." By John Geale Thomson, Grad. Inst. C. E. 



The object of the author of this paper is to show, that the land-slip which 



he deacribes, had its origin in a peculiarity of the geological poution, and 



nut in the nature of the ground iu which It occurred. To explain this view, 

 the formation of the oolitic district, so far as it relates to engineering pur- 

 poses, is described generally, and a more particular account is given of the 

 valley of the liox brook, iu which this slip took place. 



The Ashley cutting is situated about 5 miles on the London bide of Bath, 

 at the base of Kingsdowii Hill, the level of the rails being about 2'i feet 

 above the level of tlie Box Brook. 



In Mr. Lonsdale's account of the oolitic district of Bath, the valley of the 

 Box Brook is styled, a'denudcd valley of the lias, or in other words, that the 

 action of denudation has ploughed into, but not through, the lias, whereas 

 it has completely eroded the superjaecnl strata. The valley is one of the two 

 plains, which separate the parallel ridge of the great or upper oolite, which 

 occupies, with few exceptions, the sunmiits of the hills in that part of the 

 country. The extreme height of the range of hills at Lansdown, its western 

 extremity, is about SH feet above the level of the sea. The suininit of 

 Kingsdown-hill, behind the cutting, is rather higher than Box-hill, over the 

 tunnel ; and from the several heights given by ihe author it appears, that the 

 country slopes gradually from Kingsdow n-liill ti> the railway, at the rale of 1 

 in 11, exposing a slope of 1000 feel in length, to the ilecomposing action of 

 the atmosphere, and to the collection of water. I'rom the appearances of this 

 locality and other observations, the aulhur contends (hat a considerable 

 accumulation of drill from Ihc high lauds behind the cutting, had, in the 

 course of time, settled at the base of the hill, whereby llic original contour 

 of the valley of denudation had been altered ; that this had been caused by 

 the unremitting action of water and the atmosphere snioulliing down the 

 projections, and (illing up (he cavities with the unequal ellVcts of water upon 

 strata of dilTerent degrees of hardness, had left upon the slope; and that the 

 mass of loose stuff, through which the cutting was partly carried, was formed 

 from the slojie behind it, in the manner described, and was not part of the 

 original stratification. 



On the north' side of the valley, the upper oolite was generally wanting, 

 having been carried away, except from the tops of isolated hills, such as 

 Banner Down and Lansdown, which lie between the sea and the southern 

 and uiore continuous range. Owing to the slightness of the strike of the 

 country towards Bradford, it is contended that all the surface-water found its 

 way down the slope of the hill, or the line of steeper descent, little or none 

 being absorbed inlo the body of Ihe hill; that as even in winter very few 

 streams were visible, the vast quanliiy of water discovered in the cutting, 

 must have entered the surface above, and percolated the ground for a con- 

 siderable distance, and at last found its way into the Box brook, whence it 

 carried considerable quantities of sand and silt, causing the subsidences at 

 the surface which were everywhere visible. In excavating the eastern part 

 of the cutting, holes of 12 inches to 18 inches diameter were found in the 

 loose ground; these had been evidently formed by the action of water, which 

 llowed from themju clear uninterrupted streams. That great changes of the 

 surface had occurred, was further evident, from the circumstance of finding 

 at a deiith of nearly 10 feet two human skeletons, whose bones were scat- 

 tered and rubbed, as if they had been carried thither by the settling of a 

 semi-fluid mass. 



The wood-cut (Fig. 1,) shows a cross section, giving the form of the ori- 



Nouiii. Viix. I. sueiii. 



Cross section ot Box Valley, in the lino ol llie slip, 

 showing the alteration In tlic loutour of tlie valley 

 Ijy the aetumuliitiou ol llic drift. 



ginal valley, the strike of the strata, the position of the cutting, the drift as 

 supposed by the author, and the joints which traverse generally the secondary 

 stratification. The position of the cutting with regard to these is shown as 

 being partly in the lias marl, and partly in the drift. The author ascribes 

 Ihe movement of the ground, entirely to the weight of the saturated drift, 

 cither forming a joint in the marl, its tendency being down the slope AB, 

 after the removal of the ground for the purposes of the railway, had de- 

 stroyed its equilibrium, or acting upon a joint already in existence, so as to 

 detach the mass, and force it towards Ihe brook. 



In Fig. 2 is seen a section of the valley at right angles to Fig. 1, with the 

 dip of the same strata, and the direction of the valley towards the sea. 

 From a joint consideration of these two sections, it will be seen, that the 

 drift in which the cutting is situated, is based npon the slopes .VB Fig. I , and 

 CD Fig. 2. It was in a direction, compounded of these two, that the 

 ground was observed to move, and it was accordingly attributed to a sliding 

 motion of the drift, upon the surface of the marl, which idea appeared the 

 more feasible, as the liriil indication of the movement, was the separation of 



