116 
Grammes. 
Copper (rough cake) 1 3*85 
Zinc 5 - 66 
Galvanised Iron -1*12 
Block Tin 1'45 
Stream Tin 1 *45 
Lead (virgin) Trace. 
„ (common) Trace. 
These results appear to us to lead to the following con- 
clusions : — 
1. That the metal now most in vogue for shipbuilding, 
namely, iron, is that which is most readily attacked. 
2. That this metal is most materially preserved from the 
action of sea water when coated with zinc, and therefore, in 
our opinion, it would amply repay shipbuilders to use gal- 
vanised iron as a substitute for that metal itself. 
The above facts perfectly confirm those which we have 
already published in our paper “ On Galvanised Iron for 
Armour Plated Ships,” in which it was shown, that when 
iron was in contact with oak they mutually acted upon each 
other, producing a rapid destruction of the two materials, 
whilst little or no action took place between galvanised iron 
and the wood. 
3. The extraordinary resistance which lead offers to the 
action of sea water, naturally suggests its use as a preservative 
to iron vessels against the destructive action of that element ; 
and although we are aware that pure lead is too soft to 
withstand the wear and tear which ship bottoms are subjected 
to, still we feel that an alloy of lead could be devised which 
would meet the requirements of shipbuilders. 
Feeling that experiments made with a limited amount of 
sea water might not be a fair criterion of the action of the 
ocean upon metals, we repeated our experiments upon plates 
of 40 centimetres square, which were immersed for one month 
in the sea on the western coast (Fleetwood), taking the 
precaution that they should be constantly beneath the surface 
