The Sun.
London, England, 1836-08-24 00:00:00

BRITISH SCIENTIFIC

ASSOCIATION.

BRISTOL, AUG. 2?.—During yesterday and Saturday
this city has been rapidly filling, and is at this moment the
perfect seat of philosophy. We have men of all ranks—
talent from all nations. The Bristol people, particularly
the softer portion, have been on the full gaze, to see' what
kind of creature a philosopher was, and I really believe that
every stranger, whether he was a duke or. an Irish pig-
, driver, has been deemed to be sonic learned person. The
influx of strangers is eery great, and the interest excited is
in proportion. The Marquis of Northampton, who is well
known for his great love of science, arrived here on Satur-
day last, and an appeal was made to him to take the Pre-
sident's Chair, on account of the absence of the Marquis of
Lansdowne ; he immediately assented, and the Association
was thus relieved of a great difficulty. Among the scien-
tific men at present here are Dr. Lloyd (Provost of Dublin),
Professors Sedgwick, Wirer ell, and Henslow (of Cam-
bridge), Dr. Hare (of Philadelphia), Sir David Brewster
(of Edinburgh), Dr. Dalton (from Manchester), Dr.
Buckland (from Oxfotd), Mr. Davies Gilbert, the Rev.
IV. Vernon Harcourt, Professors Daubenv, Forbes, Challis,
Wheatstone. Rigaud, Shevelev, Moll, Cumming„ Johnson,
Miller, Phillips, Parigot, Wilson, Mosley, Dr. Lardner,
Sir R. Hamilton, Sir Charles Lemon, M. Von Raumer,
Mr. Russell, the Bishop of Bath and Wells, Lords Nugent
and Edward Somerset, the Dean of Wells, E. A. Sanford,
Esq , M.P., Baron Von Reaumur, Baron Charles Dupin,
Baron Browne Mill (of Berlin), Marquis Spineto, Hon.
James Talbot, Rev. W. L. Bowles, T. Moore, Esq., &c,
The sectional meetings commenced their sittings this
morning at eleven o'clock, soon after which hour most of
themwere
under the superintendence of
completely filled,
their several Presidents, elected to the office on Saturday.
The subjects at Section A (Mathematics and Physics),
held at the Merchants'-hall, were principally relating to the
progress of those questions for the solution of which several
sums of money had been appropriated.
Professor MOSLEY opened the first point by stating that
there were many gentlemen present acquainted with the
practical working of steam-engines, but the relations between
the theory and practice were not perfectly understood. The
piston of a locomotive engine was pressed on either side,
one resulting from the friction on the road, and the other
from the passive friction of the engine itself. If it was lifted
from the ground, a person endeavouring to move the wheels
would find a resistance equal to 1501bs. The cause of the
resistance was this—that the traction upon the engine in-
duced additional friction of the machinery, and that probably
was one-fourth of the whole amount of friction. If the en-
gine moved without a train, there would be a passive resist-
ance ; if a train was attached to it, there would be induced
a considerable friction-of the machinery. There were, in
fact, three causes of resistance—the friction of the carriage,
the passive resistance, the additional friction by the train—
the first and last varying according to the weight of the
train. On the other side there was the expansive power of
the steam. The quantity of work done was greater as the
velocity was less. Inclined planes on railroads he considered
to be injurious.
Dr. LARDNER said in all inclined plans more steep than
the angle of repose there was an unfavourable loss of
power. The portion of mechanical force expended in
ascending the plane was not repaid in the descent. Theo-
retically they might take advantage of the accumulative
matter as a deposit of momentum, and make a perfect me-
chanical compensation, but that was not the case in prac-
tice, because they were obliged to check the velocity in the
descent. He had never said, as had been represented, that
inclined planes were not of importance, because the friction
in the ascent was given back in the descent. When the
engine was descending, great part of its steam was going
off in the safety valve, therefore inclined planes were injuri-
ous. All the experiments led to the conclusion that every
effort should he made to attain as perfect a level as possible.
Every departure from a level, though it saved a quantity of
capital in the construction of a road, entailed an everlast-
ing expense. The result of some experiments he had
made was this—that in the ordinary state of the roads, the
force necessary on a level was 71b. per ton ; but he found
an extraordinary difference depending on the state of' the
rails, a difference amounting in some instances to such an
extent, that the friction was reduced to four pounds.
When it rained and the rails were wet, he found the fric-
tion reduced to 41b. ; but as soon as the rails became again
dry, the friction was again 71b. ; he should therefore sug-
gest, that two watering pots should be placed before the
wheels, so as to give the engine an additional power of
nearly 50 per cent. There was another point with regard
to dust : he had let himself down a very steep inclined
plane, and when he attained a speed of 60 miles an hour,
he had a quantity of sand put on the rails, and the conse-
quence was, that the steam-engine came to a stop.
As to the second subject for discussion—namely, " On
tho application of our knowledge of the phenomena of waves
with a view to the improvement of the navigation of shallow
rivers and canals."
Mr. RUSSELL said he would read from a paper the results
of various experiments he had made, in whiCh they would
perceive a very curious fact as regarded the pace of eight
miles an hour. The table was thus
4 miles an hour gave a resistance of
r-4 6 ditto ditto 91
7A• ditto ditto
11 81 ditto ditto
9 ditto ditto
1 111 ditto ditto
g 112 ditto ditto
it 2115 ditto .1- ditto
But at the rate of 20 miles an hour the vessel skated along
the surface of the water, and there was scarcely any resist-
ance at all. When a vessel was propelled at a great velo-
city, and ..then stopped, it produced a wave varying in its
form, according to the mass of the water, and he had fol-
lowed such a wave a mile and a half ; the velocity of the
wave was uniform, and independent of the velocity of the
vessel. If the vessel was going four miles an hour, this
wave would go at the rate of eight miles an hour, and he
had seen a large wave overtake a small wave, and pass it.
The waves never exceeded in height the depth of the quies-
cent water. Vessels at a slow velocity did not divide the
water, as was generally supposed, but pushed it forward
in the shape of a. wave ; but where the velocity was greater
than eight or nine miles an hour, the vessel did divide the
water. It was possible to bring the vessel completely upon
the wave, and then you had scarcely any resistance. A
velocity of between four and six miles an hour on canals was
unprofitable ; beyond 11 miles an hour you had a high ve-
locity, and comparatively little resistance. He recom-
mended a rectangular canal where it was intended the ye-
as by widening a canal with sloping
locity should be great,
banks you increasing the resisting power. He felt convinced
that by adopting a considerable velocity, the Atlantic might
easily be crossed with stearn-vesels.
At Section B (Chemistry and Mineralogy), which was
held at the Grammar School, a paper was read on arsenical
poisons by Mr. Herapath, and another description of an ap-
paratus for the analysis of mixed gases by Professor Hare,
of Philadelphia. Some observations were also read from
Mr. Herapath, on the ph,Jiornena of the Aurora Borealis,
observed in Bristol on the Stir of September, in which he
stated his opinion that this was only produced by electric
clouds, gradually withdrawing, and leaving streams of elec-
tric fluid behind ; from which opinion, however, Dr. Dalton,
in a subsequent conversation, expressed his dissent, on ac-
count of such phenomena occurring trenerally above the al-
titude of clouds. At Section C (Geology and Geography),
held at the Rooms of the Institution, Park-street, a paper
was read by Ed. Charlesworth, Esq., on Vertebral Animals
found in the Craig, and another by Mr. J. E. Bowman, hieing
notices of some recent excavations in the Bone Caverns at
CAI, near Denbigh. At Section D (Zoology and Botany),
held at Colston 's School, the commencement of a paper
was read from Dr. Richardson, on the Zoology of North
America ; and from Mr. Rootsey a description, accom-
panied with a living specimen, of the aranea avicularia, a
monstrous species 'of spider, that sometimes entraps smell
birds, brought over alive from South America amongst log-
wood. The same gentleman also communicated some ob-
servations on the growth of mangel wurzel, with the mode
of obtaining sugar and malt from it, considering that there
were certain geological situations particularly fitted for its
growth, to the extent of about 500,000 acres in the kinr,
dom. A specimen of sugar-candy, from the rhododendron
pwilicunt, was likewise exhibited, and some observations
were read from Mr. Webb Hall, descriptive of the accele-
ration of growth in wheat on light silicious sands, by ex-
posing them to heat in water ; and Dr. Daubeney described
some effects of arsenical compounds in vegetation, and on
the growth of wheat in soils in which this was largely itn-
preemated. Section E (Medical Science) was held at
Colston's School, where communications were read from
the Dublin Committee, Sir David Dickson, Drs. O'Beir-
Hie and Horston ; and Section F (Statistics) at the Chap-
ter-house, where a paper on the statistics of Glasgow
was read by Dr. Cleland, descriptive of some singular facts
in the 'history of that city. The whole of the meetings at
the various sections commenced at eleven o'clock, and by
the laws of the Association were compelled to adjourn at
three o'clock.
The evening soiree was held at the theatre, which was
crowded to excess, and presented a congregation which,
under no previous circumstances, had ever before been col-
lected in Bristol. - Soon after eight o'clock the late Dublin
President, Professor Lloyd, made an appropriate address
to the meeting on the occasion of resigning his office, and
introduced his successor to their notice, who, on enlarging
upon the objects for which the Association had met, ex-
pressed his wish that here as well as other places, political
and religious animosity would be subdued before those
exalted views which it had at heart. Dr. Daubeney, the
nextSOC-fofary,- read the address, which is ordinarily deli-
veredat the *first evening, in which he detailed the various
17 objects to whiehthe attention of the Association had been
devoted. during the past year.

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