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Scientific Intelligence. 



[no. S } new series, 



In this particular therefore the Committee urge a change of plan. 

 They consider it advisable that the whole breadth should be cover- 

 ed, that there should be four lines of rail instead of two, both on 

 the Main Pier and the Pier-head ; and that the rest of the space 

 should be fitted for the use of foot passengers. If this change is 

 made they believe that the wharfage may be found sufficient for 

 every purpose. 



The materials used in the Pier are wrought iron and Baltic tim- 

 ber with cast iron screws on the foot of the piles. Regarding the 

 iron work generally, the Committee are satisfied on all points ex- 

 cepting as to the length of the piles. They consider the arrange- 

 ment of the material excellent and the scantling adequate. And 

 with reference to the perishable nature of iron when subjected to 

 the action of salt water, and air impregnated with salt, the Com- 

 mittee have only to remark that this material is now so universally 

 employed, and has been found to answer so well in situations 

 equally trying, that they feel confident the corrosion and consequent 

 consumption of iron when so circumstanced is not such as to ren- 

 der it unsuitable to the purpose. The waste of material is evident- 

 ly retarded by the oxidized coating, which in the first months covers 

 the surface of the iron, and the subsequent decomposition of the metal 

 is so slow that no considerable annual expenditure on repairs is 

 likely to be found necessary ; while the arrangement of the iron 

 ■work in the Pier is such, as to render the operation of removing 

 injured portions practicable and simple. 



As to the length of the piles, some further consideration is in the 

 opinion of the Committee necessary. Their lengths as shown in 

 the plan which accompanies the specification appears to have been 

 determined upon a line of soundings not differing materially from 

 those now taken, and if the bottom of the sea near the coast re- 

 mained stationary, the depth at which the screws are shown in the 

 drawing would be sufficient. But as the combined action of the 

 surf and current, causes at times a very rapid motion of the sand 

 in shore, and considerable changes take place in consequence in 

 the depth of the sea along the Coast line, it is possible that piles of 

 the length suggested might be undermined. The ocean current 



