many marvellous changes. A new material
of construction has been introduced into shipbuilding, with entirely
new methods of propulsion. Old things have been displaced by new; and
the magnitude of the results has been extraordinary. The most
important changes have been in the use of iron and steel instead of
wood, and in the employment of the steam-engine in impelling ships by
the paddle or the screw.

So long as timber was used for the construction of ships, the number of
vessels built annually, especially in so small an island as Britain,
must necessarily have continued very limited. Indeed, so little had the
cultivation of oak in Great Britain been attended to, that all the
royal forests could not have supplied sufficient timber to build one
line-of-battle ship annually; while for the mercantile marine, the
world had to be ransacked for wood, often of a very inferior quality.

Take, for instance, the seventy-eight gun ship, the Hindostan, launched
a few years ago. It would have required 4200 loads of timber to build
a ship of that description, and the growth of the timber would have
occupied seventy acres of ground during eighty years.[2] It would have
needed something like 800,000 acres of land on which to grow the timber
for the ships annually built in this country for commercial purposes.
And timber ships are by no means lasting. The average durability of
ships of war employed in active service, has been calculated to be
about thirteen years, even when built of British oak.

Indeed, years ago, the building of shipping in this country was much
hindered by the want of materials.

The trade was being rapidly transferred to Canada and the United
States. Some years since, an American captain said to an Englishman,
Captain Hall, when in China, "You will soon have to come to our country
for your ships: your little island cannot grow wood enough for a large
marine." "Oh!" said the Englishman, "we can build ships of iron!"
"Iron?" replied the American in surprise, "why, iron sinks; only wood
can float!" "Well! you will find I am right." The prophecy was
correct. The Englishman in question has now a fleet of splendid iron
steamers at sea.

The use of iron in shipbuilding had small beginnings, like everything
else. The established prejudice--that iron must necessarily sink in
water--long continued to prevail against its employment. The first
iron vessel was built and launched about a hundred years since by