[Footnote 2: In consequence of the seas breaking over the boat, a large
number of diagrams were destroyed, and, on account of the roughness of the
weather, cards were only taken with the greatest difficulty. The records
of power developed are therefore not put forward as authoritative.]

In connection with this subject it may perhaps be of interest to give
particulars of a French and American steam launch; these we extract from
the United States official report before mentioned.

_Steam Launch of the French Steamer Mouche_.

Length on low water level 27 ft. 10-1/2 in.
Breadth 5 ft. 11 in.
Depth to rabbet of keel 3 ft. 3-1/3 in.
Draught of water aft 2 ft. 1-1/2 in.
Weight of hull and fittings 2,646 lb.
Weight of machinery with water in boiler 3,473 lb.

The boat is built of wood, and coppered. The engine consists of one
non-condensing cylinder, 7-1/2 in. in diameter and 5.9 in. stroke. The
boiler has 4.3 square feet of grate surface. The screw is 21-2/3 in. in
diameter by 43.3 in, pitch. The speed is 7 knots per hour obtained with
245 revolutions per minute, the slip being 19.7 per cent. of the speed.

The United States navy steam cutters built at the Philadelphia navy yard
are of the following dimensions:

Length 27 ft. 7½ in.
Breadth 7 ft. 10 in.