on the Preservation of Metals by Electro-chemical Means. 97 
junctions and nails were covered. with rust, and that had been 
in a ship for some years, showed that the action was weakened 
in the case of imperfect connexions by distance, and that the 
sheets near the protector were more defended than those re- 
mote from it. Upon this idea I proposed, that when ships, 
of which the copper sheathing was old and worn, were to be 
protected, a greater proportion of iron should be used, and 
that if possible it should be more distributed. The first ex- 
periment of this kind was tried on the Sammarang, of 28 guns, 
in March 1824, and which had been coppered three years be- 
fore in India. Cast iron, equal in surface to about 1-80th of 
that of the copper, was applied in four masses, two near the 
stern, two on the bows. She made a voyage to Nova Scotia, 
and returned in January 1825. A false and entirely un- 
founded statement respecting this vessel was published in most 
of the,newspapers,—that the bottom was covered with weeds 
and barnacles. I was at Portsmouth soon after she was 
brought into dock: there was not the smallest weed or shell- 
fish upon the whole of the bottom from a few feet round the 
stern protectors to the lead on her bow. Round the stern 
protectors there was a slight adhesion of rust of iron, and upon 
this there were some zoophytes of the capillary kind, of an 
inch and a half or two inches in length, and a number of mi- 
nute barnacles, both Lepas anatifera and Balanus Tintinna- 
bulum. Yor a considerable space round the protectors, both 
on the stern and bow, the copper was bright; but the colour 
became green towards the central parts of the ship; yet even 
here the rust or verdigrease was a light powder, and only 
small in quantity, and did not adhere, or come off in scales, 
and there had been evidently little copper lost in the voyage. 
That the protectors had not been the cause of the trifling and 
perfectly insignificant adhesions by any electrical effect, or by 
occasioning any deposition of earthy matter upon the copper, 
was evident from this,—that the lead on the bow, the part of 
the ship most exposed to the friction of the water, contained 
these adhesions in a much more accumulated state than that 
in which they existed near the stern; and there were none at 
all on the clean copper round the protectors in the bow; and 
the slight coating of oxide of iron seems to have been the 
cause of their appearance. 
I had seen this ship come into dock in the spring of 1824, 
before she was protected, covered with thick green carbonate 
and submuriate of copper, and with a number of long weeds, 
principally Yuci, and a quantity of zoophytes, adhering to dif- 
ferent parts of the bottom; so that this first experiment was 
V5). 67. No. 334. Feb. 1826. N highly 
