It will probably be remembered that the military Zeppelin Z III
was compelled to make a forced landing in France. This ship was
of similar construction to L 1, but of smaller volume, her
capacity being 620,000 cubic feet. A trial flight was being
carried out, and while above the clouds the crew lost their
bearings. Descending they saw some French troops and rose again
immediately. After flying for four hours they thought they must
be safely over the frontier and, running short of petrol, made a
landing--not knowing that they were still in France until too
late. The airship was taken over by the French authorities.

Until the year 1916 the Zeppelin may be considered to have passed
through three stages of design. Of the twenty-five ships
constructed before the war, twenty-four were of the first type
and one of the second. Each type possessed certain salient
features, which, for simplicity, will be set out in the form of a
tabulated statement, and may be useful for comparison when our
own rigid airships are reviewed.

Stage 1.
Long parallel portion of hull with bluff nose and tail.
External keel with walking way.
Box rudders and elevators.
Two cars.
Four wing propellers.

Stage 2.
Long parallel portion of hull with bluff nose, tail portion
finer than in Stage I