ast 14 years, but this paper has not been found in
any of the French archives. References to the original text indicate
that the naval report dealt very extensively with the _Steam Battery_.
Some of his comments on the battery appeared in _Proces-verbaux des
Seances de l'Academie des Sciences_.[12] Marestier considered the powers
of the battery to have been overrated due to fanciful accounts of some
laymen writers. He was aware of the shortcomings of the double hull in a
steam vessel at the then-possible speeds, but he apparently thought two
engines, one in each hull and each with its boilers would be better than
Fulton's arrangement of boilers in one hull and engine in the other. He
noted that the paddle wheel turned 16-18 rpm and that steam pressure
sustained a column of mercury 25 to 35 centimeters. The safety valve was
set at 50 centimeters. Fuel consumption was 3-5/8 cords of pine wood per
hour.

In view of the access Marestier is known to have had to American naval
constructors, shipbuilders, and engineers, it is highly probable that he
not only obtained the building plan of the ship but also some of the
earlier project plans from the builders and from Fulton's
superintendent, Stoudinger. It is, therefore, a great misfortune that
his lengthy report on the _Battery_ cannot be produced.

A French naval officer who investigated the ship, M. Montgery, also
wrote a description, published in "Notice sur la Vie et les Travaux de
Robert Fulton."[13]

[Illustration: Figure 5.--FLOATING BATTERY _Spanker_ built, in England
by William Barnard, at Deptford on the Thames, and launched June 14,
1794. Rigged as a bomb ketch, its length is 111 feet 7 inches in the
keel, extreme beam 42 feet 4 inches, depth of hold 8 feet. Upper deck
plan also shown.]

It should be noted in regard to what Montgery wrote about the
_Battery_, that in 1821 it had been considered desirable to disarm the
ship. The engineer in charge, William Purcell, had reported that as
there were not proper scuppers, dirt and water had entered the hull and
had collected under the engine and boilers, causing damage to the hull,
and also that with guns removed, the _Battery_ would float too high for
the paddle wheel to propel the vessel; so it had been decided to remove
all machinery as well as the armament.

Montgery's description, published in 1822, was taken from his report to
the Minister of Marine and Colonies. It noted the battery was made of
two hulls separ