. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. 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 di
. The Civil engineer and architect's journal, scientific and railway gazette. Architecture; Civil engineering; Science. 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 t
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