CORNISH VIADUCTS. 225 



of the girders, projecting beyond the face of the arch, in 

 order to carry materials. An overhead road was also made 

 on the top of the centre, upon which worked a hand travelling 

 crane. By these means the remainder of each arch was 

 finished, beginning at one end of the viaduct and proceeding 

 in order to the other. 



" Twenty-five girders were constructed for five arches out 

 of the eight, and timber centres were provided for four arches 

 out of the eight, so that the girder work was one bay ahead 

 of the timber work till the last arch was reached." The 

 abutments ^vere also carried to the solid rock, and were 

 built of solid masonry 20 feet thick at the base, and pro- 

 vided with splay wing walls, battering 1 in 3, to retain the 

 bank. 



On the arches came two rows of jack arching, which 

 brought the whole surface up to a nearly even level, a slight 

 slope being made from piers to centre of arch to allow for 

 drainage of water, and from these points pipes were carried 

 through the arch to enable the water to run off. The whole 

 of the jack arches were covered with a layer of asphalte, thus 

 absolutely preventing water from getting in and washing out 

 the lime from the joints, to form stalactites on the arch below. 

 All that now remained was to finish the string course, man- 

 hole corbellings and railings, and to form the permanent way 

 approaches on either side by means of tipped earth and dry 

 walling. The whole viaduct was now ready to receive the 

 ballast and rails. It was then passed by the Board of Trade, 

 the line was diverted between the trains, and Moorswater 

 Viaduct was opened for traffic. 



Bolitho Viaduct, which was also undertaken by the Com- 

 pany, is 182 yards long, and 113 feet high. It was built 

 under peculiar circumstances, on account of the Company 

 being unable to obtain extra land without great cost. They 



