116 ANNUAL OF SCIENTIFIC mSCOVERT. 



preserved, but tlie exterior was not slow in presenting traces of 

 oxidation. "\Vo tiien continued tiie action of the reservoirs bj'^ a 

 small jilate of zinc, applied to the exterior of the shell, in electric 

 communication witli the reservoirs, and with its inferior part 

 pinniped into tiie sea. 



" Some experiments made in this condition, for more than a year, 

 have given us a complete success; some boats, plunged since the 

 end of December, 1808, in a pond formed by some old salt-works, 

 and where the water of the ocean is renewed at every tide, have 

 been preserved until to-day, witliout presenting tiie least spot of 

 oxidation. Every time tliat a part of the system was found to be al- 

 tered, by wear or by accident, some sensible traces of rustappeared, 

 and then disappeared after the preparation was renewed. Many 

 boats placed in the same circumstances, but without preparation, 

 have been perforated successively during this time. Some of 

 these boats were scoured with acid before being submitted to this 

 experiment ; the others, immersed immediately after their depart- 

 ure from tlie work-shop, presented at tlie time of their putting in 

 water numerous spots of rust, \vhich all disappeared in the lirst 

 8 daj's of their immersion. To avoid the emplt)yment of the elec- 

 trodes of zinc, we plunged one of tlie extremities of a copper wire, 

 covered with gutta-percha, in the liquid of the reservoirs, and the 

 other in the sea ; but in this case, the results have been less satis- 

 factory." — Comptcs Rendus, July 26, 1809. 



MAKING FOUNDATIONS IN MARSHES. 



A new process of making foundations for bridges in marshy 

 soils has been recently used on a branch line of the Charentes 

 Railway Company, in France. Tliis line crosses a peat valley to 

 the junction of two small rivers. The thickness of peat was so 

 great that any attempt to reach the solid ground would have 

 been very expensive. In order to obtain cheaply a good support 

 for the bridge two large masses of ballast accurately rammed 

 were made on each bank of the river, and a third one on the 

 peninsula between the two. The slopes of these heaps were 

 pitched with dry stones, for preventing the sand from being 

 washed away by the rains or by the Hoods in the rivers. Over 

 the ballast a timber platform is laid; this platform carries the 

 girders of the bridge, which has two spans of about 60 feet each. 

 When some sinking down takes })lace, the girders are easily kept 

 to the proper level by packing the ballast imder the timber j^lat- 

 form ; this packing is made by the })late layers with their ordi- 

 nary tools. This simple and cheap process has succcedi d (]uito 

 well. The same difliculty was overcome 1)V a different plan on 

 an ordinary road near Algiers, This road crosses a peaty plain 

 nearly one mile bnxid ; the lloods and elasticity of the ground 

 prevented the formation of an embankment. The road was to 

 be carried over a viaduct across the valley, but the foundations 

 of this viaduct presented serious difliculties, the thickness of peat 

 or of compressible ground being nearly 8U feet. It was quite 



