772 REPORT — 1901. 



which are mechanical in the above cases can be made with success. It was 

 pointed out that aluminium can be welded and soldered. The melting and 

 casting, rolling and forging, luirdening and annealing, of aluminium were next 

 dealt with. 



Probably the widest field is still in the purification of iron and steel. At liigh 

 temperatures the metal decomposes nearlj' all metallic oxides, and prevents blow- 

 lioles by combining with the gases which form the Iioles. 



The author referred to tlie use of aluminium when alloyed with copper for the 

 production of aluminium bronzes. The breaking load varies from 44 to 39 tons 

 per square inch in tlie case of alloys containing 8 to 12 per cent, aluminium. It 

 has a golden appearance, and is suitable for hydraulic work on account of its non- 

 corrodible properties. 



3. Recent Observations on Bridges in Western China. 

 By R. LocKHART Jack, B.E. 



During 1900, while travelling in the West of China, in Szechuan and Yunnan, 

 I was struck by the variety of Ciiinese bridges, ranging as they do from pontoons 

 and even large baskets of shingle supporting a temporary decking, to stone and 

 iron bridges of large span. 



On the headwaters of the Min, Fou, and Mekong rivers the single rope bridge 

 is used, on whicli tlie traveller, by the aid of a runner to which he is fastened, 

 crosses from one bank to the other. The rope is of plaited bamboo, from two to 

 three inches in diameter, while the runner employed is a half cylinder of liard 

 wood ten inches long. 



The bamboo is also much employed for suspension bridges, a very good example 

 of which is to be found at Shih Chuen. It is composed of sixteen hawsers, each 

 from 7 to 8 inches in diameter, tightened by capstans, and is 240 feet long by ten 

 wide. The decking, of wicker work, is laid upon fourteen of these hawsers, the 

 other two acting as guard rails. The bridges are entirely renewed at intervals of 

 one to three years. 



In other districts suspension bridges are built of wrought iron, chains or bars, 

 the decking following the curvature of the chains, which, however, is very slight, 

 that of the Yangtse near Likiang being less than 20 feet on a span of 320. This 

 bridge, the largest single span we saw, is built up of eighteen chains, the links of 

 which were 11 inches long of 1^^ inch bar iron. The chains are anchored to 

 castings bedded in the masonry abutments, and are tightened by driving wedges 

 between the links. This type of bridge is said to have been in existence at about 

 the beginning of the Christian era, and possibly much earlier. 



Cantilevers and trestle bridges are used where timber is plentiful, the latter 

 being generally covered with a tiled roof and lined at the sides with stalls. The 

 timber is mostly soft wood, but they last very well owing to the protection 

 afforded by the roof. 



The greatest triumphs of the Chinese, however, are their masonry bridges^ 

 which are exceedingly numerous in the wealthier districts of Szechuan. Broadly, 

 they are of two kinds : those in which slabs of stone are used as girders, and those 

 which embody the principle of the arch. A good example of the former was being 

 erected at Chiung Chow, 50 miles S.W. of Chengtu, and consisted of a bridge 

 nearly 700 feet long by 15 wide, formed of stone slabs laid on edge, and carried 

 on thirty-three tiers, each 40 feet by 4. The whole of the stone used was a red 

 sandstone cut into blocks. 



Of the arch bridges the largest is at Ning Shih, also of sandstone, where a 

 bridge about 600 feet long (including masonry approaches) is carried across a 

 tributary of the Yangtse Kiang on three spans of over 100 feet each. 



One-arch bridges with the roadway rising to the centre by steps are very 

 common over small streams, and bridges of twelve to eighteen arches are occa- 

 sionally met with. 



There is reason to believe that the Chinese used such bridges as have been 

 described at a very early period, and it would be of interest to make a study of 



