to be sawn out a year before it was used and stacked, with battens
between the planks, so as to allow of the free circulation of the air.
Similar regulations were put in force for the beam pieces, knees, and
other portions of the ships.

Much trouble was caused by the injurious effects of bilge-water and foul
air in the holds of ships, and various remedies were devised from time
to time. In 1715 structural improvements were devised to allow of the
bilge-water flowing more freely to the pumps, and trunks were fitted to
the lower decks to convey air to the holds. In 1719 it was proposed that
the holds of ships should have several feet of water run into them in
the early spring in order to cool them, and that it should not be pumped
out till August; but this remedy was never extensively practised. In
1753 Dr. S. Hales proposed a system of ventilation by means of windmills
and hand-pumps, which produced excellent results. It was noticed that
the accumulation of carbonic acid gas and foul damp air in the holds,
not only set up rapid decay in the ship, but also most injuriously
affected the health of the crews. Dr. Hales' system was employed in the
_Prince_ from 1753 to 1798, and it was considered that the durability of
this vessel had been greatly increased. It was also reported by Lord
Halifax that the mortality on the non-ventilated ships on the coast of
Nova Scotia was twelve times as great as on those vessels which were
fitted with Dr. Hales' appliances.

There are not many records in existence of the merchant-vessels of this
period. Fig. 54 is a representation of an armed East Indiaman which was
launched at Blackwall in 1752. Her length of keel was 108 ft. 9 in.;
breadth, 34 ft.; and burthen, 668 tons. She was named the _Falmouth_,
and was constructed by the famous shipbuilder, John Perry, of Blackwall
Yard. She was commenced almost exactly two years before the date of her
launch. Like all her class, she was heavily armed.

[Illustration: FIG. 54.--The _Falmouth_. East Indiaman. Launched 1752.]

At the close of the war against France and Spain, which lasted from 1744
to 1748, great complaints were made of the weakness of our warships at
sea. It was also found that the establishment of 1719 had not been
adhered to, and the dimensions of ships were not fixed in accordance
with any particular standard. The first defect was remedied by the
placing of as many standards of wood, or iron, on the different decks as
could be