2 
jtern. I have read another work by an 
American author, J. W. Griffiths, showing 
several drawings of vessels. The yacht Sylva, 
built in 1850, is a step in advance of Mr. Scott 
Russell, inasmuch as the midship section is 
farther aft. This author speaks very definitely 
in page 47, and says, “ that there is no theory 
for building ships at all.” He condemns Mr. 
Scott Russell and his wave line in page 33. 
“ It has been found that at an angle of 6 ° on 
the line of flotation from the longitudinal axis 
or 12 ° with the two sides united, a wave was 
not generated at the highest speed, namely, 20 
miles per hour, which steamboats have attained 
in the United States.” But he gives an illustra- 
tion in page 31, wherein it is clearly 
shown, how he contradicts himself. He 
says, — “ Who has not often witnessed a 
rival steamboat holding (remaining, con- 
tinuing by) at a convenient distance a much 
faster boat.” He ascribes this fact < to the 
power of attraction, but it is simply taking 
advantage of the wave formed by the faster 
vessel to push the slower one on. 
This author is not satisfied with what Mr. 
Scott Russel had done, but he goes to prove 
the contrary, and accordingly writes a great 
deal of rubbish, to uphold his theory that there 
is no such thing as a wave formed by vessels 
moving swiftly through the water. This is 
where my. theory begins. I assume that any 
body moving through the water forms a wave 
or waves. That according to the size and 
celerity of the body so is the size and speed of 
the wave. For instance, a marble dropped a 
foot into water will give one size and speed.; a 
pound weight from 8 feet gives a larger and 
quicker wave ; and a stone of 200 lbs. weight 
dropped from 10 feet high will give a still 
larger and quicker wave. So with vessels of 
different sizes at the same speed, they will have 
waves with different speeds, and a vessel at 
different speeds will form different sizes and 
speeds of wave. This will ever be a difficulty in 
designing vessels, as steamers for instance are 
always lighter at the end of their voyage, and 
sometimes they are sunk far below their regular 
draft by cargo, and sailing vessels on the other 
hand cannot command the wind to drive them 
at their proper speed. 
Coming back again to dropping a marble 
into the water. It displaces so much water ; 
that goes off in a ring, then the water 
gathers together and rises up beyond 
its original level over where the marble 
entered, then it drops at the same time 
another ring is being formed further out. 
This is repeated for some time, but every time 
getting less ; at the same time circles are ex- 
tended farther and farther away, but also 
getting less and less. The same is true of a 
vessel with a wave-line for her bow, moving 
through the water. No break is formed ; the 
water is raised up by the bow of the vessel 
"pressing it* to one side, when the full width of 
the vessel is in, if I may so speak, the wave 
recedes, but the re-action immediately sets in 
and another one forms ; and, after it others — 
t getting less, and less. My principle is, to form 
the sides of vessels straight for the length of 
the second wave, and let the third wave fall 
into the run — i.e., the after part of the vessel. 
Advantage may be taken of the second and 
third waves, and let the fourth fall in behind. 
Such is the theory. I shall now quote a few 
examples, proving that it is correct. These are 
not to my satisfaction ; but, still the best I can 
get. In this American work on ship-building, 
page 133, and plates 19 and 20, are descrip- 
tions and drawings of the ship Universe. Of 
her this author says, “Thb Universe, while 
building) was visited by the sceptical and the 
curious; and it would havb been no difficult 
matter for a practised eye to have read from 
the observer’s glance, the shake of the head, or 
the shrug of the shoulders, that she was set 
down by both shipbuilders and masters 
as a ship that would be partially if 
not wholly unmanageable. In a word, 
that fast sailing and good steering were 
entirely out of the question. The ship was 
finished, notwithstanding) and has completed 
her first voyage, and is found to roll remarkably 
easy, steer well, and sail fast ; as 
some shipmasters have abundantly proved 
who were sailing in company.” The reason 
of her speed and other good qualities 
is her having a straight piece in her 
middle, opposite the second wave, and the third 
wave falling in behind. Her speed would have 
been better had she a finer bow, at the expense 
of a bluffer stern. The model exhibited is, in 
my estimation, superior to her. 
The next one I will refer to is the Telegraph 
Steamer. This steamer, some years ago, traded 
between Sydney and some southern port — Mel. 
bourne, I believe. She was what I would call 
a vessel with two ends and no middle, he 
