Year: 1879




punched holes.


These tests were repeated nine times, with the
general results although two of the iron plates
broke sooner than any OF the steel ones.


definite average Of elongation under tensile
strain having proved therefore very dihcut to OBJ
tain, Mr.. Marte shows in elaborate tables the per-
centages of extension. AS to the comparative cost Of
iron and steel ships he proves that the superior
lightness of the latter in proportion to it's bulk
would afford much greater capacity for the carry
ing OF dead weight cargoes, while for those OF the
ordinary description there would be just as much
space in iron vessels The quantity of material
required in building steel ship would DO less than
that required building OF iron. and the small
of cost Of the former the latter would be
compensated in few years by the additional earn
ings.


OXIDATION OF STEEL


"What information l have gained, concludes Mr..
Martel "of the comparative deterioration OF steel
and iron from oxidation is not such to warrant the
opinion which appears to be entertained by some
that steel deteriorates much rapidly than iron
when used for shipbuilding. A striking hlustra-
se oyds j, in hs es
Navigation Company and has been employed in acl
tual service up to the present time and is Perhaps
the oldest steel vessel now ahoat. She was ex-
amned about four years ago and the bottom plating
from the keel to the water line was, understand,
the vicinity Of the water line, where deterioration
would naturally be expected the plates were found to
be wasted, but not more than might have been the
under the circumstances with iron plating
Another that of the steel sailing ship of 200
before alluded to. This ship has been engaged
in general trade India and elsewhere for the last
fourteen years. aud 1 am informed when last sur
veyed she was not found to have dete-
riorated to the extent which would
have been experienced in iron vessel
under the circumstances. Mr.. Bessener
recently informed me that he had made experiments
with view ascertain the comparative corrosion of
steel and iron in nitric acid. and that the results
would to bear out this experience. have, it is
true, heard of light draught river boats built Of
steel deteriorating rapidly, but have not yet been
able to clear my mind of SUSPICION that either the
speciality Of the cargo. or the nature of the
waters navgated, or some such surrounding
circumstances. such careleSSDeSS. might have
the wasting alleged to have taken place in
of 1000 tons at present running between this
country and the Continent which are built Of
STEEL They were built in 1865. and have there
fore been afoat the last thirteen years. =
The attention of shpowners cannot be too strongly
drawn to the false economy of running their vessels
too continuously instead of placing them IN dry
dock at fitting intervals, so that the surfaces of
plating can be properly examined, scraped and
painted when found necessary. BY q due regard to
this whether the vessels be of iron Steel my ex-
perience leads to the conclusion that often much
unnecessary outlay might be avoided and the cost
OF detention and coating would be far more than
compensated for by the durability of the vessels.
II steel is to replace iron in the immediate
future need not say the stride will be enorno
one, and great changes may have to follow, but
nevertheless look forward to such changes without
misgivings. for know they will be undertaken with
the utmost and with every endeavor to abide
strictly by the teachings of experience and with duo
regard to the principles involved therein"