great question--that of navigation. It is felt that, in these go-ahead
days, we must be paying not less attention to our maritime than to our
inland arm of commerce; and this has brought the question of wood
_versus_ iron ships again into prominent notice. The advocates of iron
shew that the dry-rot, so destructive to wood, cannot enter metal;
that lightness and speed, those prime essentials, are insured by the
use of iron; that iron ships are safer, more easily repaired, and
cheaper than vessels built of wood; and that they are more lasting.
The chief objection hitherto has been the liability of iron to become
foul in tropical climates; but this now appears to be in a measure
overcome. According to Mr Lindsay: 'An admixture has been applied,
termed "Anti-Sargassian Paint," which has been found to answer the
purpose better than any yet discovered. From the experience of its
properties, we cannot say that in itself it is yet sufficient; but it
appears a fair substitute till some other preparation is discovered. A
gentleman at Glasgow,' he adds, 'has already discovered a compound,
which, being mixed in a fluid state with the iron, is expected to
answer the desired purpose. There is another disadvantage which will
soon be overcome--the greater liability to error in the compasses of
iron ships; an error which, however, also occurs, though perhaps to a
less extent, in every wooden ship. By a most ingenious invention,
which will shortly be made public, such errors in any ships, under any
circumstances, can at all times be at once detected.'

An important patented process for producing tapered iron, has been
explained before the Franklin Institute at Philadelphia--one by which
every variety of taper may be produced, or combinations of taper, with
flat or other forms; and seeing how much tapered iron is used on
railways, in many kinds of machinery, in ships and steamers, the
subject may be considered worthy of more than a mere passing notice.