34 
BRITISH ASSOCIATION.- 1835 . 
An Account of some Experiments recently made on the Buoys in 
Kingstown Harbour , with a view to protect from the action of Sea 
Water the Metals, and especially the Iron-work , attached to 
them. By Edmund Davy, F.R.S., M.R.I.A., $*c., Professor of 
Chemistry to the Royal Dublin Society. 
Last year an enlightened member of the Royal Dublin Society, 
Mr. John M’Mahon, made the author acquainted with the fact that 
the iron-work attached to the new buoys lately put down in Kings¬ 
town Harbour had undergone a very rapid corrosion by the action 
of sea-water on it; and shortly after, the Commissioners of Public 
Works acting as Commissioners of Kingstown Harbour directed 
his attention to the subject, with the view of ascertaining the cause 
of such corrosion, and the means of prevention. 
The new buoys* are precisely similar to the buoys, of the most 
approved construction, now used in Portsmouth Harbour. The 
whole surface of each buoy is sheathed with copper, except the bot¬ 
tom and about three inches of the smaller end, which is covered 
with lead, fastened to the copper by metal nails. A bolt passes 
through the whole length of the buoy, and is terminated at each end 
by a shackle. The lower shackle has a bridle patent chain fastened 
to it by means of a bolt and a thin pin called a forelock , which is 
such an important part that on its preservation mainly depends the 
security of the ships moored to the buoyf. The bridle chain is se¬ 
cured to a larger chain-cable and moorings, by means of shackles, 
bolts, and forelocks. The forelocks require to be examined about 
once a year, and replaced if defective. The bolt, shackles, chains, 
and forelocks are all of the best wrought iron. 
On examining the buoys the author found all the iron-work at 
and near their bottoms very much corroded; and the corrosion ap¬ 
peared to be most considerable on the iron in the immediate vicinity 
of the lead, where it was about one eighth of an inch deep, and the 
metal was so much indented as to exhibit a coarse fibrous structure. 
So rapidly had the iron-work corroded in about six months, that 
had it continued at the same rate for two years the buoys (in the 
opinion of competent judges) would have been quite unfit for the public 
service. The copper and lead attached to the buoys were in a good 
state of preservation. 
The extraordinary corrosion of the iron-work appeared to be due 
to an electrical action produced in sea water by the contact of the 
iron with the lead joined to the copper, on the buoys; these metals 
being preserved at the expense of the iron. The author submitted 
his views on the subject to the Commissioners, and suggested the 
propriety of removing a circle of about three or four inches of lead 
* The author exhibited a drawing of one of these buoys, 
f Some years since the Lord Lieutenant’s yacht broke from her moorings 
in Kingstown Harbour in consequence of the defective state of the forelock. 
