222 
appeared unchanged, whilst in the case of the iron, they had 
a dark blue-black appearance, owing to the formation of 
gallate and tannate of iron. 
In order to ascertain the comparative action of soft and 
salt water upon iron and galvanized iron Avhen in contact 
with oak under identical circumstances, he made the following 
series of experiments. 
Plates of galvanized iron having 18 inches of surface lost 
during three months the following weights: — 
SOFT WATF.H. SEA WATER. 
Plate No. 1 . 
„ No. 2. 
. . 0.10 grains. 
.. 0.11 „ 
„ No. 3 0.095 grains. 
„ No. 4 0.090 ,3 
Similar plates of iron lost during the same time : — 
SOFT WATER. SEA WATER. 
Plate No. 1 . . . 
„ No. 2. . . . 1.52 
55 
No. 
1.23 grains. 
2.40 grains. 
„ No. 4 2.38 „ 
There can therefore he no doubt that galvanized iron offers 
great advantages, the action of water on it being less than a 
tenth of the same action on ordinary iron. As there is no 
doubt that iron when galvanized is in the most favourable 
electrical condition to resist the action of oxygen, being in 
an electro-negative condition, it follows that in all probability 
the use of galvanized iron would be very advantageous in 
armour-plated and other iron ships. The Author hoped 
that Government and other large ship builders would avail 
themselves of this suggestion, and make experiments on a 
large scale to verify the results lie had obtained. 
