204 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



n«iuNE, 



ing that llie absorbent power, in this respect, was cveu less than in the case 

 of the npper chalk. The quantity of water contained in a cube foot of 

 saturated middle chalk was rather more than two gallons. 



A specimen of the lower chalk was found to contain more than 10 parts 

 of water in 1,000 parts, about three-fourths of which were rapidly parted 

 with, ou exposure to a perfectly dry atmosphere; but the rest, amounting 

 to more than the quantity of water contained in the upper chalk, iu its 

 ordinary state, was not parted with by any exposure, short of a vacuum. 

 Ou subsequent exposure to a saturated atmosphere, more than ISJ parts 

 of water in 1,000 parts, were absorbed, and when the specimen was satu- 

 rated, its water contents exceeded 2j gallons per cubic foot. 



It was staled, that the upper chalk might generally be regarded as the 

 conducting, and the lower chalk as the containing, part of the formation, so 

 far as water was concerned ; and that chalk must be regarded as a rock, 

 which everywhere admitted the percolation of water, receiving into itself, 

 aud conveying to its lower beds, the water that fell on, or was brought lo, 

 its surface. This readily explained the uniformly dry appearance it pre- 

 sented, aud the absence of any streams, arising from mere surface drain- 

 age, where extensive exposure of the roc k itself occurred. It also ap- 

 peared that particular bands of rock contained much more water than 

 others, some, indeed, being apparently, though not really, dry, when below 

 the surface of permanent wetness; while others gave off water readily, 

 and to a large extent. 



The probable effect of rain-fall upon the surface of the exposed chalk 

 was then considered, aud it was estimated, that at least 1 8 inches descended 

 annually to what was called the surface of permanent wetness, maintain- 

 ing a general and rude parallelism with the surface of the ground ; but 

 when the chalk rock was permanently covered with impermeable soils, as 

 iu the r.ondou basin, the position of the surface of permanent wetness was 

 liable to extreme variation, and to be most seriously affected, as lateral 

 percolation was then the only source of wetness. 



Ou the other hand, it was thought, that a large portion of chalk rock 

 existed in a slate of uniform and permanent wetness, and that wherever the 

 gault extended, undeilyiug the chalk and keeping up the water, there 

 must be, at and below a certain depth from the surface, a supply of water 

 to the extent of 180 millions of gallons for each square mile one yard in 

 thickness ; and that the surface of permanent wetness, dependent chiefly 

 on the present rainfall, was so far above this lower surface of saturation, 

 as lo ensure a supply at least equal lo one-half of the rain falling on the 

 immediately surrounding district. 



May 7. — The paper read was " On the Application of li'ater-Pfesiiure,as 

 a Motive Power, for working Cranes and other kinds of Machinery." By 

 Mr. VV. G. Armstrong, F.R.S., Assoc. Inst. C.E. 



The oliject of the paper was to direct attention to the advantages of a 

 more extended application of hydraulic pressure, as a motive power, and to 

 point out the means of attaining this desirable end; illustrating the argu- 

 ments by descriptions and drawings of the engines on this principle, already 

 erected, since the year 1845, when the author first designed a crane, to be 

 worked by the pressure of water from the street water-pipes, at Newcastle- 

 upon-Tyne. 



The principle of these engines, as applied to cranes, was described to be 

 very simple. In order to lift a weight, the water, under a pressure of about 

 100 feet head, or more, being admitted through a slide valve into a cylinder, 

 exerted a force ou a piston, whose rod was connected with the hoisting- 

 chain, so arranged by passing over several pulleys, as to increase its length 

 of travi'l to the requisite duty to be performed; the piston receding from the 

 pressure therefore raised the weight to the height required. The lowering 

 of tlie weight was accomplished by a reverse action, and the crane was 

 turned in either direction by a similar action of a smaller cylinder, whose 

 idston rod was connected with a rack, working into a circle of teeth, fixed 

 to the base of the moveable frame of the crane. 



The action of these machines was described to be very smooth and steady, 

 ingenious appliances being adopted for obviating the shock that would 

 otherwise be caused by the sudden closing of the slide valves, and all the 

 different operations being under the perfect control of a few regulating 

 handles. In cases of a great diversity of power being required, separate 

 cylindeis were used, so arranged, as that their action could be combined, 

 accoidiiig to the force required. The speed of working had no other limit 

 than the size of tljc supply pipe. 



Allusion was niaile to the advantage of employing hydraulic pressure in 

 iiiercantilo docks, for hoisting heavy weights, for whipping light goods out 

 of shi|i9, and for opening and shutting dock gates, swing bridges, and sluices. 

 lit facility of transmission, its safely, and constant readiness for use, ren- 

 dered it peculiaily suitable for th se purposes. It wcuild generally be pre- 

 ferable in such cases to employ steam power to force the water, rather than 

 lo be dependent upon town water-works; and a tnnk upon a tower, or upon 

 an eminence, would form a convenient magazine of power, enabling the 

 engine to act continuously with an uniform load. Large air-vessels had 

 also been successfully employed, insteail of an el. valed tank. 



Hydraulic pressure might, also, in many cases, be advantageouslv eni- 

 ployed for purposes requiring continuous rotation. There were many natural 

 situations where mountain streams might be arrested, or surface-water be 

 iin|iouiided on elevated ground, and he conveyed by a pipe into a neighbour- 

 ing valley, where great mechanical efficiency might be derived from a small 



supply of water, by the use of water-pressure engines. In mining opera- 

 tions, also, the danger and inconvenience of underground steam-engines 

 might be obviated, by substituting water-pressure engines, conveying the 

 water down the shaft in pipes, and returning it to the surface, by the action 

 of the pumping engine abovegrouod. In such cases the water was merely 

 the vehicle for transmitting power into the mine. 



A water-pressure engine had been lately very successfully applied by the 

 author, in South Hetton Colliery, for the traction of wagons upon an 

 underground railway. Similar engines had also been erected in the lead 

 mines at Allenheads, for lifting ore, and other purposes. Reservoirs were 

 there formed upon the neighbouring hills, and pipes were carried into the 

 mines to supply the engines, the expended water flowing out by a level. 

 Other engines of the same description were also in course of erection, for 

 surface operations, at the aame place, such as crushing ore, and raising 

 minerals from the shafts. 



In their general character, these engines were similar to reciprocating 

 steam-engines. The slide valves were balanced by equal pressures in op- 

 posite directions, and were constructed to open very spacious water passages. 

 The liability to concussion, on the closing of the eduction port, was obviated 

 by the application of relief valves, which were lifted by the compressive 

 action of the piston, cansing it to act for an instant, as a pump, in forcing 

 back the opposing water into the supply pipe. In cases where the engines 

 had been applied to hauling, or winding, four cylinders placed diagonallyr in 

 pairs, had been used. In other cases, two cylinders had been applied, the 

 uniformity in the motion of the column being maintained by a loaded 

 plunger. The winding engines were reversed by a slot link apparatus, 

 similar to that of a locomotive engine, and which was worked by the pres- 

 sure of the water, acting under the control of a valve. The regulating 

 and reversing valves were each placed at the mouth of the shaft, at a 

 distance from the engine, the operation of which could thus be directed 

 with great accuracy and safety. 



The drawings which accompanied the paper gave representations of an 

 Hydraulic Crane, for shipping coals at Glasgow; Hydraulic Platform Cranes, 

 at the railway station, Newcastle-upon-Tyne; Hydraulic Hoisting Machines, 

 at the warehouses of the Albert Docks, Liverpool; a Water-pressure Engine, 

 for a crushing-mill at Allenheads; a similar engine used at the same place, 

 for winding; and numerous details of all these machines. 



May \i. — The paper read was "On the Construction of the Permanent 

 IVay of liaiiways ; with an Account of the wrought iron Permanent H'ay, 

 liid down 07i the Main Line of the North Midland Railway. By Mr. W. 

 H. Uarluw, M. Inst. C.E. 



The author commenced by entering into the question of the maintenance 

 and renewal of the ordinary railways, analysing very minutely the expenses 

 under the different heads, and showing to what causes the derangement of 

 the line might be attributed. The cost of maintenance was staled to be 

 dependent on two causes, the effect of weather, &c., and the disturbance 

 produced by traffic; and from a summary of the expenditure of the different 

 lines belonging to the Midland company, it appeared that the former 

 amounted to 20/. or 30/. per mile per annum, and the latter varied from 2d. 

 to 2'd. per train per mile. After a line was consolidated, by far the greater 

 part of this expenditure was due to the derangement caused by the passage 

 of the trains, which first produced an uneven joint, then loosened the joint 

 key, and then disturbed the sleeper, so that at length the whole of the per- 

 manent way generally was degraded. — With regard to renewal, it had been 

 estimated by the officers of the London and North. Western Railway, that 

 on their line the rails would last twenty years, and the sleepers, if 'creo- 

 soted,' twenty years, but if unprepared only twelve years; now as the dura- 

 tion of service of the rails was dependant on the amount of the traffic, and 

 that of the sleepers on the weather, it was quite evident, that on lines 

 having less traffic than the London and North-Western, the proportionate 

 expense of renewing the sleepers would be much greater, and would increase 

 as the amount of traffic diminished. 



In endeavouring to seek a remedy for this, the author conceived, that, by in- 

 creasing the dimensions of the bridge rail, sufficient width might be obtained 

 for it to take its own bearing in the ballast, without the use of either trans- 

 verse sleeper, or longitudinal supports; and, moreover, that such a con- 

 struction wouuld possess great strength, be very durable, and be capable of 

 being renewed at a moderate expense. He therefore proposed a bridge rail, 

 13 inches iu width, 5f inches in depth, and weighing 1261b. per lineal 

 yard. There was some difficulty at first in getting it manufactured, but 

 Messrs. liolckow and Vaugban, of Middlesburough-on-Tees, had overcome 

 all the practical difficulties, and now produced tails of the required size, 

 with hard metal in the upper portion, and ductile metal in the lower, by 

 which both durability and strength were insured. The joint was made by 

 either a cast or wrought iron chair, or saddle, which received the ends of the 

 rails, and into which they were keyed with wooden keys. The gauge was 

 preserveii by means of a tie-bar, fitted and keyed into sockets on the chairs. 

 An experimental length of road on this construction had been laid down 

 on the main line of the North Midland Kaihvay, the cost of which was 3323/. 

 per mile ; but it was thought, that in future this might be reduced to 24S7/. 

 per mile, by reducing the weight of the rails to 100 lb. per yard, and the 

 chairs in proportion, as it was found by experiment, that these rads were 

 greatly in excess of strength, being as much as three times stronger than the 



