that if a skilful and experienced
naval constructor, aided by an able corps of assistants, should design
an airship of a diameter of not less than two hundred feet, and a
length at least four or five times as great, constructed, possibly, of
a textile substance impervious to gas and borne by a light framework,
but, more likely, of exceedingly thin plates of steel carried by a
frame fitted to secure the greatest combination of strength and
lightness, he might find the result to be, ideally at least, a ship
which would be driven through the air by a steam-engine with a velocity
far exceeding that of the fleetest Atlantic liner. Then would come the
practical problem of realizing the ship by overcoming the mechanical
difficulties involved in the construction of such a huge and light
framework. I would not be at all surprised if the result of the exact
calculation necessary to determine the question should lead to an
affirmative conclusion, but I am quite unable to judge whether steel
could be rolled into parts of the size and form required in the
mechanism.

In judging of the possibility of commercial success the cheapness of
modern transportation is an element in the case that should not be
overlooked. I believe the principal part of the resistance which a
limited express train meets is the resistance of the air. This would be
as great for an airship as for a train. An important fraction of the
cost of transporting goods from Chicago to London is that of getting
them into vehicles, whether cars or ships, and getting them out again.
The cost of sending a pair of shoes from a shop in New York to the
residence of the wearer is, if I mistake not, much greater than the
mere cost of transporting them across the Atlantic. Even if a dirigible
balloon should cross the Atlantic, it does not follow that it could
compete with the steamship in carrying passengers and freight.

I may, in conclusion, caution the reader on one point. I should be very
sorry if my suggestion of the advantage of the huge airship leads to
the subject being taken up by any other than skilful engineers or
constructors, able to grapple with all problems relating to the
strength and resistance of materials. As a single example of what is to
be avoided I may mention the project, which sometimes has been mooted,
of making a balloon by pumping the air from a very thin, hollow
receptacle. Such a project is as futile as can well be imagined; no
known substance would