1824.] 
ported by. concurring circumstances and 
strengthened by long tradition, may be 
fairly assumed, that the scene of action 
was confined to the immediate vicinity 
of Battle-bridge. 
Tt is certain that the Romans, from their 
first invasion of Britain, were assisted by 
elephants in their battles with the aboriginal 
inhabitants. Polyenus relates, that Julius 
Cesar, in forcing the passage of the Thames, 
had recourse to the stratagem of placing 
one of these animals in his front, bearing 
some archers and armed men upon his 
back. The Britons, astonished at the 
sight of such a stupendous beast, were 
struck with dismay, and precipitately fled 
from their posts.* The circumstance of 
the skeleton of an elephant haying been 
many years ago discovered on digging in a 
field at Battle-bridge, by “ a great searcher 
after antiquities,’ affords some confirma- 
tion to the opinion, that this was the spot 
where Paulinus gained his great victory 
over the army of Boadicea. 
A detailed account of this battle, 
which forms a very prominent feature 
in the early annals of our country, is 
given in the topographical work I have 
before mentioned, extracted chiefly from 
the Annals of Tacitus and the History 
of Dio Cassius, lib. xii. c. 1-12. 
Iam, &c. 
Islington, J. NELson. 
Aug. 31, 1824. 
Ps 
For the Monthly Magazine. 
On the PRESERVATION of the COPPER- 
SHEATHING of SHIPS. 
ji Regen is scarcely any single de- 
partment of practical science so 
pregnant with interest to a maritime 
nation like Great Britain, as the recent 
discoveries made by that illustrious che- 
mist Sir Humphry Davy, applicable to 
the preservation of the copper-sheath- 
ing of vessels from corrosion. The ex- 
penditure, occasioned by the rapid de- 
struction of the sheathing of his Ma- 
jesty’s ships, alone forms a very con- 
siderable item in the naval department 
of the public service. But the loss to 
the country from their decay bears but 
a small proportion, during time of peace, 
to the aggregate loss sustained by the 
mercantile interests, from similar causes. 
Indeed the very considerable expense of 
copper sheathing, added to its rapid de- 
cay, serves to prohibit its use in nume- 
rous instances, notwithstanding the addi- 
* Polyenus, lib. viii. 
+ Seymour's Sury. Lond, yol, ii, p. 869. 
On the Preservation of the Copper-sheathing of Ships. 
223 
tional security it gives to a ship, by pre- 
venting the opening of her planks, and 
consequent leakage,in bad weather. But 
in spite of this expense and sacrifice, 
every ship destined for navigating the 
tropical seas, if not protected by 
sheathing, in a very short period be- 
comes perforated through the bottom 
by the innumerable marine animalculze 
which abound in the warmer latitudes. 
It would perhaps be an interesting in- 
quiry to many persons concerned, to 
compute the annual loss which the 
ship-owners of this great maritime na- 
tion sustain, from the corrosion and 
destruction of copper-sheathing; but 
although the amount must be obviously 
very great, it would encroach too much 
upon your miscellaneous columns to 
enter into such investigation, I 
shall therefore proceed to give your 
readers an abstract of the valuable re- 
searches of Sir H. Davy, which promise 
to lead to the most important results in 
the preservation of shipping. The 
president, in the communication of his 
important researches on this subject, to 
the Royal Society, after alluding to the 
rapid decay of the sheathing of the ships 
in his Majesty’s service, observes: 
It has been generally supposed that sea- 
water had little or no action on pure copper, 
and that the rapid decay of the copper on 
certain ships was owing to its impurity. 
On trying, however, the action of sea-water 
on two specimens of copper, sent by J. 
Vivian, Esq. to Mr. Faraday for analysis, 
I found the specimen which appeared ab- 
solutely pure, was acted upon even more 
rapidly than the specimen which contained 
alloy: and on pursuing the inquiry with 
specimens of various kinds of copper 
which had been collected by the Navy 
Board and sent to the Royal Society, and 
some of which had been considered as re- 
markable for their durability, and others for 
their rapid decay, I found that they offered 
only very inconsiderable differences on their 
action upon sea-water; and consequently 
the changes they had undergone must have 
depended upon other causes than the ab- 
solute quality of the metal. 
Sir Humphrey then describes the 
chemical agency between sea-water and 
a sheet of copper as follows: 
When a piece of polished copper is suf- 
fered to remain in sea-water, the first effects 
observed are a yellow tarnish upon the 
copper, and a cloudiness in the water, 
which takes place in afew hours. The hue 
of the cloudiness is at first white, it then 
changes to green. Within a day a blueish 
green precipitate appears at the bottom of 
the vessel, which constantly accumulates, 
at the same time the surface of the copper 
corrodes, 
