140 
Scie7iiific Litelh'gence* 
[no. Sj 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 phange 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 •:n 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 
equrilly 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 difi'ering 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 \^'buld 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 
