a start in the race of airship construction as we could ill
afford to concede.

We may here state that all of the ships of this class which had
been ordered were not completed, the later numbers being modified
into what was known as the 23 X class; four in all of the 23
class were built, of which two--Nos. 23 and 26--were built by
Messrs. Vickers, Ltd., at Barrow, No. 24 by Messrs. Wm. Beardmore
and Co., at Glasgow, and No. 25 by Messrs. Armstrong, Whitworth
and Co., at Selby, Yorkshire.

In many respects the closest similarity of design exists between
No. 9 and No. 23, especially in the hull, but it will be of
interest to mention the salient differences between the two
ships.

The length of the hull, which in No. 9 was 520 feet, was
increased in No. 23 to 535 feet, and the number of gasbags from
seventeen to eighteen. This gave a total volume of 997,500 cubic
feet compared with 890,000 cubic feet in No. 9, with a disposable
lift under specification conditions of 5.7 tons as opposed to 3.8
tons.

The longitudinal shape of No. 23 is a modified form of "Zahm"
shape, the radius of the bow portion being twice the diameter of
the parallel portion, while the stern radius is three times the
same diameter.

In design the hull framework is almost a repetition of No. 9,
particularly in the parallel portion, the same longitudinal and