22 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



[JA^tJARV, 



with four props fitted between tliem, and there was a slip feather at each 



joining of the end boards ; there were also interior hoops of timber, strutted 



from the centre by spokes, hke tliosc of a wheel, in the situation of the 



Fig, 1. 





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chains, by which the stone was borne ; the whole was hooped outwardly 

 with iron, and made in the strongest manner, consistent with lightness, to 

 resist external pressure. 



Where any of the stones were under low water, wooden frames were used 

 in boring the holes for inserting the lewis. I'lie casks were towed to the 

 spot, and at low water were attached to the stone, by means of chains pas- 

 sing thvough the lewis rings and over the casks. At the top of each cask, 

 tlie spindle of one end of the chain, was passed through the ring of the other, 

 pulled tight, and fastened backward, by a small hempen line, to the chain. 

 Oil the flowing of the tide, which rose at that spot from 10 feet to l.'i feet, 

 the casks and the stone floated together, and were towed away by means of 

 a lioat ; the stone was then moored over the spot where it was intended to 

 be laid, and at about half ebb, by means of a loug-handled knife, the small 

 lines, by which the chains were attached, were cut; the casks rose to the 

 surface, and the stone, being guided into its position by boat-hooks, fell into 

 its destined spot : the chains were then drawn away, and the casks were 

 again fixed on, at low water, to the next stone to be floated. 



The advantages gained by these means were obvious. The coast was too 

 rugged and ilangerous to admit of a crane-lighter being used, and if it could 

 have been worked the stones were much too heavy to be lifted on deck, and 

 even then, there would have been some difliculty in moving a lighter such a 

 distance. The stone displacing its own bulk of water, left not quite 13 cwt. 

 per ton for the casks to lift ; the sjiecific weight of water and of the stone 

 being 3C cubic feet, and l.l cubic feet respectively to the ton. Each cask 

 weighed 2.'> cwt., and displaced 445 cubic feet of water ; so that two casks 

 lifted a gross weight of 34 1 tons of stone, the displacement of water caused 



by which was equivalent to lifting 12^ tons. AVhen rough weather came on, 

 the casks were easily disengaged, and were rolled to above high water-mark, 

 without the least injury. Even in a heavy surf stones have been buoyed out, 

 by means of a long towing-line fastened to the casks. The strength and 

 tightness of the casks were very remarkable ; after being used for 24 hours, 

 scarcely a gallon of water was found in each cask. This must, in some mea- 

 sure, be attributed to the swelling of the wood. 



Four casks were used, and with them a length of 400 feet of the founda- 

 tion was eft'ectually secured, in the course of a few months, and not a stone 

 has since been removed. 



To ensure still further the stability of the stones when laid, the author 

 proposed to have a chain cable passed through a lewis in each stone, and 

 permanently fastened to the pier, so as to connect the whole together. 



The application of these casks has not been confined to floating stones. 

 In Band', as well as in Macduti" Harbour, great inconvenience was felt, from 

 the want of a sufticient depth of water. In case of a vessel being fully loaded 

 up in the harbour, and the depth of water being insufficient, four of these 

 casks were attached, by means of chains previously passed under the vessel's 

 keel ; with the flowing tide, a lift equal to 44 tons, was given by the casks, 

 which were afterwards easily disengaged, when the vessel was outside, in 

 deep water. To a vessel of 100 tons register, a deficiency of la inches in 

 her draught of water, has been supplied by these means, the want of which 

 water would otherwise have occasioned detention and loss. 



The author believes, that casks would be found equally efficacious, in re- 

 moving stones from the beds of rivers, &c., as from dangerous and exposed 

 parts of the sea-coast. 



The cost of each of the casks was 8/., ond they were not at all injured by 

 the work they were used upon. The charge for labour, in making lewis- 

 holes, fixing on the casks, and removing the stone three miles, was only 

 l.v. Crf. per ton, which included lowering them into their proper places anil 

 towing back the casks; in short every expense, except that of finding casks 

 and lewises. 



The lewises used (Fig. 3), were of the simplest kind, the shank part in- 

 serted was 2 inches in diameter at the bottom, tapering to \\ inch at the 



Fig. 3. 



top, where a ring was welded into an eye; into this ring, the chains were 

 fastened, before letting in the lewis, which was done by means of two guide 

 rods of iron, close to the mouth of the jumper-hole ; the wedge was then 

 inserted, by means of a pair of long-handled tongs ; a punch bar of iron 

 being set on its top to hammer it down. Although the lewis-holes were 

 perfectly cylindrical, not a single instance occurred of the lewis being drawn 

 out, even when raising the heaviest stones. 



The author thinks, that the slope of Banff Harbour, which is ."i horizontal 

 to 1 perpendicular, is much too flat, as no superincumbent weight being added 

 to the foundation course (on which the whole slope abutted), the stones 

 were liable to be moved outward, by the heavy recoil of the receding waves, 

 acting at low water on their surface and on the inner bed joints. This was 

 the case with the new pier at Banff, which was designed by the late Mr' 

 Telford, and has also been foimd, in many other liaibours, to be a cause of 

 constant outlay for repairs. The author suggests, that a curved slope of 1 to 

 1, reckoning from the top of the parapet to the foundation, should be used, 

 and he has found that even a less slope than 1 to 1 answers very well, even 

 in very exposed situations, if the foundation can be let into the rock. 



Fareham's Railway Switch. 

 A model was exhibited of Param's Railway Switch. 

 The object of this invention was explained to be, that by means of an 

 apparatus attached to the locomotive engine and under the command of the 

 driver, the switches of the railway should be moved into such positions, as 

 would be necessary to divert the train into the required direction, and thus 

 render it unnecessary to have persons in attendance, to place the switches 

 correctly for the next coming train. In the arrangements of this apparatus, 

 care was taken to avoid too sudden contact between the switches and the 

 projecting arm which caused the movement. It was stated, that if any ob- 

 jection existed to placing the control of the switches under the engine- 



