10S 
BRITISH ASSOCIATION. —1835. 
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 anv 
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 elementarv 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 Vibration of Railways. By Capt . Denham, R.N. 
Capt. Denham ascertained that the vibrating effects of a passing 
laden railroad train in the open air extended laterally on the same 
level 1110 feet, (the substratum of the positions being the same,) 
whilst the vibration was quite exhausted at 100 feet when tested ver¬ 
tically from a tunnel. 
The tunnel was through a stratum of sandstone rock: the rails 
laid in the open air on a substratum of 12 feet of marsh over sand¬ 
stone rock. The method of testing was by mercury reflecting ob¬ 
jects to a sextant. The experiments were made in the neighbour¬ 
hood of Liverpool. 
On certain points in the Theory of the Construction of Railroads . 
By the Rev. Dr. Lardner and C. Vignolles. 
On the Monthly Reports of the Duty of Steam-engines employed in 
draining the Mines of Cornwall. By John Taylor, F.R.S. } 
Treasurer of the British Association. 
Mr. Taylor observed that he had found at this and other Meetings 
of the Association considerable interest to be expressed with regard 
to this method of recording the actual effect produced by the con- 
