ment has given every satisfaction.

To the envelope of the N.S. is rigged a long covered-in car. The
framework of this is built up of light steel tubes, the rectangular
transverse frames of which are connected by longitudinal tubes, the
whole structure being braced by diagonal wires. The car, which tapers
towards the stern, has a length of 85 feet, with a height of 6 feet.
The forward portion is covered with duralumin sheeting, and the
remainder with fabric laced to the framework. Windows and portholes
afford the crew both light and space to see all that is required. In
the forward portion of the car are disposed all the controls and
navigating instruments, together with engine-telegraphs and voice
pipes. Aft is the wireless telegraphy cabin and sleeping accommodation
for the crew.

A complete electrical installation is carried of two dynamos and
batteries for lights, signalling lamps, telephones, etc. The engines
are mounted in a power unit structure separate from the car and reached
by a wooden gangway supported by wire cables. This structure consists
of two V-shaped frameworks connected by a central frame and by an
under-structure to which floats are attached. The mechanics'
compartment is built upon the central frame, and the engine controls
are operated from this cabin.

In the original power units two 250 horse-power Rolls Royce engines
were fitted, driving propellers on independent shafts through an
elaborate system of transmission. This proved to be a great source of
weakness, as continual trouble was experienced with this method, and a
fracture sooner or later occurred at the universal joint nearest to the
propeller. When the modified form of ship was built the whole system
of transmission was changed, and the propellers were fitted directly on
to the engine crankshafts.

At a later date 240 horse-power Fiat engines were installed, and the
engineers' cabin was modified and an auxiliary blower was fitted to
supply air to the ballonets for use if the engines are not running.

In the N.S. ship as modified the car has been raised to the same level
as the engineers' cabin, and all excrescences on the envelope were
placed inside. This, added to the improvement effected by the
abolition of the transmission shafts, increased the reliability and
speed of the ship, and also caused a reduction in weight.

The leading dimensions of the ship are as follows: length, 262 feet;
width, 56 feet 9 inches; height,