66 British Association for the Advancement of Science. 
which it appeared that the wire best resisted fracture and impact 
when it was under the tension of a weight which, being added to 
that impinging upon it equalled one third of the force that was ne- 
cessary to break it. 
On the Solid of least Resistance. By J. S. Russevy. 
Mr. Russell was called upon to give an account of a new form for 
the construction of ships, by which they should experience least re- 
sistance from the water in their passage through it. A vessel of 75 
feet keel and 6 feet beam had been built on this new formation, 
and made the subject of very accurate experiments, from which it 
appeared that this vessel, named the “ Wave”, experienced much less 
resistance in passing through the water than vessels of the very finest 
formation and from the best builders on the old construction. 
Mr. Russell then detailed very minutely the mode of forming any 
vessel on his plan when the length and breadth were given. The 
peculiarity, in general terms, appears to be the formation of the en- 
trance lines from parabolic ares, so as to have a point of inflection at 
about one sixth part from the bow of the vessel, before which the bow 
is concave externally, giving the finest possible entrance at the stern, 
at an angle of contact infinitely small, and behind which the con- 
vexity is external and the formation elliptical to the midship section, 
after which the formation becomes wholly ellipsoidal. Mr. Russell 
had been induced to consider this solid as the solid of east resistance 
from a phenomenon that appeared to distinguish this form from all 
others, namely, that it entered the water at the highest velocities 
without breaking in the slightest degree the evenness of its surface ; 
that, while at high velocities all other formations dashed the water 
into spray or raised it in waves above the surface, this vessel, at ve- 
locities of 16 or 18 miles an hour, appeared to give no motion to any 
particles of water, excepting such as happened to lie in its path. He 
considered the entrance into smooth water without ruffling the sur- 
face as the criterion of minimum resistance. 
Mr. Russell observed, that the form had been constructed on a 
hypothetical view of the subject, viz. that the minimum force requi- 
site to alter the position of any fluid particle would be that which 
gave to the particle a uniformly accelerated velocity through the 
former half of its path, and a uniformly retarded velocity during the 
remainder; that the well-known relation of the coordinates of the 
parabola accomplished this in the manner formerly explained, but 
that he rested for the proof of the correctness of the theory upon 
the experiments he had already adduced. 
Mr. Russell then described a very simple mode of construction, by 
which the ordinates of a circle or a table of sines might be used so 
as, in the most elementary mechanical manner, to form a very close 
approximation to the solid of least resistance ; and he concluded by 
drawing the lines of a vessel of given dimensions according to the 
new formation of least resistance. 
On certain points in the Theory of the Construction of Railroads. 
By the Rev. Dr. LARDNER and C, VIGNOLLES. 
