f their
dimensions, and at these appropriate speeds the resistances will vary
as the cubes of these dimensions. The fundament upon which the law is
based has recently been shown to have found expression in the works of
F. Reech, a distinguished French scientist who wrote early in the
century. There are no valid grounds for supposing that the discovery
of Reech was familiar to Froude; but even were this so, it is
abundantly evident that, although never claimed by himself, there are
the best of grounds for claiming the law of comparison, as now
established, to be an independent discovery of Froude's.

Dr. Froude began his investigations with ships' models at the
experimental tank at Torquay about 1872, carrying it on
uninterruptedly until his death in 1879. Since his decease, the work
of investigation has been carried on by his son, Mr. R. E. Froude, who
ably assisted his father, and originated much of the existing
apparatus. At the beginning of 1886, the whole experimental appliances
and effects were removed from Torquay to Haslar, near Portsmouth,
where a large tank and more commodious offices have been constructed,
with a view to entering more extensively upon the work of experimental
investigation. The dimensions of the old tank were 280 ft. in length,
36 ft. in width, and 10 ft. in depth. The new one is about 400 ft.
long, 20 ft. wide, and 9 ft. deep. The new establishment is more
commodious and better equipped than the old, and although the
experiments are taken over a greater length, the operators are enabled
to turn out results with as great dispatch as in the Torquay tank. The
adjacency of the new tank to the dockyard at Portsmouth enables the
Admiralty authorities to make fuller and more frequent use of it than
formerly. Since the value of the work carried on for the British
government has become appreciated, several experimental establishments
of a similar character have been instituted in other countries. The
Dutch government in 1874 formed one at Amsterdam which, up till his
death in 1883, was under the superintendence of Dr. Tideman, whose
labors in this direction were second only to those of the late Dr.
Froude. In 1877 the French naval authorities established an
experimental tank in the dockyard at Brest, and the Italian government
have just completed one on an elaborate scale in the naval dockyard at
Spezia. The Spezia tank, which is 500 ft. in length by about 22 ft. in
breadth, is fully equipped with al