1845.] 



THE CIVIL ENGINEER AND ARCHITECT'S JOURNAL. 



m 



was, that in an exposed situation, there was a risk of the wheel-work 

 being destroyed. He believed tliat the contractors had found much 

 ad\Mntag(' from its use. He had used, at the works of Lossiemouth 

 Harbour, a crane of a somewhat similar description. The jib was com- 

 posed of two spars, witli the hoisting-chain working between them ; 

 the radius of its sweep was GO feet, so tliat any spot within a circle of 

 120 feet in diameter was fully commanded by it, and that extent of 

 work could be completed without moving the crane. 



Mr. Gale presented two drawings of improved moveable jib cranes, 

 the alterations in which had been suggested by the serious accidents 

 which had occurred from the failure of the ordinary cranes. On in- 

 vestigating the circumstances connected with these accidents, he found 

 that in general they had arisen from the snapping of the jib-chain. 

 After numerous experiments, it occurred to liim that this defect might 

 be obviated by attaching the jib chain to the top of the post, instead 

 of fixing it to the end of the jib; this alteration was |)roductive of 

 great advantage, the strain was found to be less than one-iialf that of 

 the single jib crane, and it consequently required fewer men to work 

 it. He iiad also applied a rope instiad of a chain for working liie jib, 

 as it was preferred by some builders, and he had also made some minor 

 improvements in the other parts of the cranes. These kind of cranes, 

 were, he believed, introduced by Mr. W. York, at Glasgow, in the 

 year 1S33, and Mr. Gale had used the improved sort in 1S42, at the 

 erection of the New Court Houses, Glasgow. Since that time many 

 builders had adopted them, and their advantages were becoming daily 

 so evident that he would send, early in the ensuing session, a paper 

 descriptive of them. 



Mr. Thomson believed that cranes of this description were first used 

 at Glasgow by builders. The contractor for the Grangemouth Docks, 

 under Sir John Macneil, employed them in 1811 and 1812 with much 

 advantage; bethought them the most useful kind of cranes for general 

 work. 



The President agreed in the opinion of the general utility of the 

 cranes; he had been so pleased with them, that he requested Mr. 

 Howkins to present to the Institution the model of that used at Granton 

 Pier. With respect to the date of the introduction of the swinging- 

 jib, or moveable derrick crane, it was used at Granton Pier by Messrs, 



Orrell of Liverpool, in 1838, and he believed that it had been commonly 

 used by them for some time previously. 



Mr. WiCKSTEED presented a drawing of the tackle used in elevating 

 the pipes of the "stand-pipe" of the East London Water-works, fig. G. 

 A piece of timber A, ',) inches s(piare, was attached vertically to the 

 upper flanch of the pipe, and hi'ld below by an iron girdle B, which 

 encircled the body of the pipe ; guy ropes were attached to the top 

 of the upright, which served as the points of suspension for the snatch 

 blocks, through which were passed the fall ropes from the large and 

 the small crab winches. The iron girdle had at its opposite sides two 

 liivots, which traversed the lower end of two timber jibs C, connected 

 at their upper ends by a cross piece D, from the centre of which were 

 suspended the blocks and tackle connected with the large crab by 

 which the pipes were raised. When each pipe had arrived at its 

 lieight, the jib frame was drawn up vertically by the tackle from the 

 small crab, and the pipe was lowered to its position ; the pins were 

 jjut into the flauches, and the whole apparatus was raised and attached 

 to it, in order to use it for raising the next pipe. This process was 

 n?])eated, until the stand-pipe finished at a height of upwards of 130 

 feet. It was stated to be a very simple and economical mode of pro- 

 ceeding. 



Sir M, L BiiUNEL exhibited a model of the scaffolding used by Sir 

 Christopher Wren in the erection of the Monument, on Fish Street 

 Hill. It was formerly the property of Sir William Chambers, and had 

 been given by Mr. H'-athcote Russell, C.E., to Sir M. I. Brunei, who 

 presented it to the Institution. (See Engraving in Journal, Vol. I., 

 1838, p. 267.) 



Mr. Allen presented a sketch, fig. 7, of the circular travelling crane 

 now in use for erecting the central or ventilating tower at the new 

 Houses of Parliament. It consisted of a circular base curb, at the top 

 of which was fixed a toothed rack. In the centre was fixed a vertical 

 post, with diagonal braces, carrying a centre point, around which the 

 travelling crane worked, with its hoisting crab on the top. At the 

 foot of each leg was inserted a toothed wheel, working into the rack, 

 so that by means of winch handles the whole could be made to rr- 

 volve. It was stated that the saving in labour was very considerable, 

 but that the saving as compared with tlie cost of constructing scaf- 

 folding would be very much greater. 



Fig. 6,— Tackle used In elevating the pipps of the • Stand, 

 pipe' ut the East London Waler-ivorkj, 



Fifr, ",— Revolving Scaft'oliling ustJ at the new Houses of Purliiuneut. 



