XXXVl PROCEEDITfGS OF THE GEOLOGICAL SOCIETY. 



yard in the kingdom, and constructed under great difficulties from 

 the nature of the soil. Cast-iron dock-gates were here introduced, 

 which led afterwards to the constructing of ten large iron dock- 

 gates for Sevastopol, described in the Transactions of the Institute 

 of Civil Engineers. Shortly before his father's death George Rennie 

 designed London Bridge, the boldest and one of the most beautiful 

 stone bridges in existence. He equilibrated the arches during con- 

 struction, and assisted materially in completing it ; but his brother 

 John was appointed engineer, in consequence of George Bennie hold- 

 ing the appointment at the Mint. 



Another important work erected under the Rennies' direction was 

 the biscuit-machinery at Weovil, near Gosport ; this was the first 

 complete arrangement for making biscuit by machinery. The com- 

 and chocolate-mills of Deptford, as well as the more magnificent 

 establishment called the E-oyal William victualling-yard at Ply- 

 mouth, were also due to the skill of George Bennie ; the latter was 

 completed about 1835. 



In 1828, George Bennie wrote a paper for the Boyal Society " On 

 Eriction and Besistance of the Surfaces of Solids ; " and the series 

 of experiments were continued and communicated to the same 

 Society in 1831, in a paper " On the Eriction and Besistance of 

 Eluids." 



In 1832, having previously given up the appointment at the Mint, 

 he completed the elegant stone bridge at Staines, made after his 

 design. During hot weather certain openings were observed in the 

 parapet of this bridge, which induced him to consider the question of 

 the expansion of stone by heat, and resulted in his making experi- 

 ments on the expansion of solid bodies by heat, published in 1834. 



In the introduction of railways he played a most important part ; 

 for after the biU for the Manchester and Liverpool railway had been 

 thrown out, in cod sequence of numerous defects, the line proposed 

 by Stevenson being very circuitous in order to avoid the Chat Moss, 

 George Bennie was called in. He made new surveys in a more 

 direct line, and straight over the widest part of the Chat Moss, 

 which he accomplished by making the survey in frosty weather ; 

 and instead of considering it to be an impossible matter to take 

 railways over it, he estimated it to be about the easiest and cheapest 

 part of the line, viz. ^30,000 per four miles distance ; and the actual 

 cost for this was only £27,719. In 1836 and 1837 George Bennie 

 laid out the railway from Birmingham to Liverpool, to cross the 

 Mersey by a magnificent viaduct at Buncorn. 



In Belgium he executed the Namur and Liege, and the Mens and 

 Manage railways ; and the beautiful bridge over the Mouse, of five 

 arches of stone, is one of the works of good architectural taste con- 

 structed by him. 



In 1834 he wrote a valuable paper for the British Association on 

 the History, Principles, and Practice of Hydrostatics, Hydraulics, 

 and Hydrodynamics. 



In 1836 George Bennie took up the mode of propelling ships 

 with the screw propeller, and succeeded in establishing its merits. 



