le steamer was not yet driven off the ocean, and we find the
Scotia crossing in between eight and nine days, at a speed of 13 or 14
knots. In 1858 ten and a half to twelve and a half days was allowed
for the passage between Liverpool and New York. So as we recede we
finally arrive at the pioneer vessels, the Sirius and Great Western,
crossing in fourteen to eighteen days at a speed of 6 to 8 knots. For
these historical details an interesting paper may be consulted, "De
Toenemende Grootte der Zee-Stoombooten," 1888, by Professor A. Huet,
of the Delft Polytechnic School.

Each of the last two or three decades has thus succeeded, always,
however, with increasing difficulty, in knocking off a day from the
duration of the voyage. But although the present six-day 20 knot boats
are of extreme size and power, and date only from the last two or
three years, still the world of travelers declares itself unsatisfied.
Already we hear that another day must be struck off, and that five-day
steamers have become a necessity of modern requirements, keeping up a
continuous ocean speed of 231/2 knots to 24 knots. Shipbuilders and
engineers are ashamed to mention the word _impossible_; and designers
are already at work, as we saw in the Naval Exhibition, but only so
far in the model stage; as the absence of any of the well known
distinguishing blazons of the foremost lines was sufficient to show
that no order had been placed for the construction of a real vessel.
It will take a very short time to examine the task of the naval
architect required to secure these onerous and magnificent conditions,
five days' continuous ocean steaming at a speed of 24 knots.

The most practical, theory-despising among them must for the nonce
become a theorist, and argue from the known to the unknown; and,
first, the practical man will turn--secretly perhaps, but wisely--to
the invaluable experiments and laws laid down so clearly by the late
Mr. Froude. Although primarily designed to assist the Admiralty in
arguing from the resistance of a model to that of the full size
vessel, the practical man need not thereby despise Froude's laws, as
he is able to choose his mode: to any scale he likes, and he can take
his experiments ready made by practice on a large scale, as Newton
took the phenomena of astronomy for the illustration of the mechanical
laws. Suppose then he takes the City of Paris as his model, 560 ft. by
63 ft., in round numbers 10,000 tons displacement