It appeared that the Zealandia was powered by seven Scotch
marine boilers. There were two stokeholds, a forward and an aft
stokehold. The forward stokehold was a space about thirty feet
long, running from side to side of the ship, and about ten feet wide
between the No. 7 boiler and the port and starboard bunkers, and
Nos. 1, 2 and 3, which were on the after side of this space. The other
boilers, Nos. 4, 5 and 6, were behind boilers Nos. 1, 2 and 3. No
details were given about the arrangements there, except that it
was described as the after stokehold, and behind that again came the
engime-room. Scotch marine boilers consist of a metal cylinder of
substantial size with three heating units, two being described as
wing or upper furnaces, and the other as the lower furnace which is
in the centre. Hach furnace has a place where the coal itself is
consumed with an ashpit underneath. There is a lead through to
a combustion chamber at the back, and from there the flame, hot
gases and smoke are led through the smoke tubes back to the front
of the boiler where they escape into the smoke box and from there
away to the ship's funnel. The essential feature of Scotch marine
boilers is that the tubes do not carry any water, but carry only the
flame and hot gases. The water itself is contained in the cylindrical
part of the boiler, forming, as it were, a water jacket. This com-
pletely surrounds and encloses the three heating units. The water-
jacket at the back, behind the combustion chamber, contains, as it
were, a wall of water enclosed between the back wall of the combus-
tion chamber and the back wall of the boiler itself, a space about
fourteen inches from side to side. The two walls are secured one
to another by a number of stays, which are threaded steel rods
varying in size from 13 up to 1% inches in diameter. They are
threaded for their full length and screwed through holes which are
made in each of these two walls, which are themselves threaded.
They are further secured by nuts which are secured on to the out-
side of the wall of the boiler itself and inside the wall of the combus-
tion chamber so as to prevent any possibility of the metal walls
expanding or becoming distorted. There are about five hundred of
these stays in a boiler, so that, in view of the possibilities of corrosion
and other injury, it is a matter of some moment to ensure that they
are maintained in proper order, and precautions are taken so that
any corroded, broken, or defective stays may be removed and
replaced. At the time and on the date mentioned above the stay
in the port margin of the back combustion chamber in the third row
from the bottom fractured in such a manner that one short end was