The Sun.
London, England, 1867-12-27 00:00:00

AMERICA.

NEW YORK, Dec 26, 6 p.m.
The steamer Chicago arrived hero yesterday.
COMMERCIAL INTELLIGENCE.

Gold, 134. Sterling Exchange on London, 1101.
5-20 United States Bonds, 1081. Illinois, 131.
Erie, 731, Cotton, Middling Upland, 151.
PHILADELPHIA, Dec. 26.
Petroleum, standard white, 241.

CROOKIIAVEN, Dec. 27 (8.15 am.)

The Cunard steamship China is now passing
Browhead Signal Station en route for Queenstown.

FRANCE.

BOURSE, Dec. 26, Three o'clock.--The market
closed as follows :

4} per Cent.
End of month —
3 per Cent
End of month 6B 65
Credit Mobilier 167 50
End of month 166 25
Credit Foncier 1365
Ead of month 1362 50
RIILWA

Bank Shares 3120
Ital4an Loan
End of month 45 7i
Mexican Loan
Do. Bonds
Spanish Throes
Home Debt 3l 50
Deferred 35

Account,

Orleans
Northern • .. 117114
Lyons and Mediterranean
Southern..... 5514
Western
Eastern .. s3l}

Sardinian

Austrian

Lombard
North of Spain

Saragossa, -
Email

CHRISTMAS LECTURES AT 771 E ROYAL

LVS7 ITUTION.

The usual short course of lectures at the Royal
Institution, adapted to a juvenile auditory at
Christmas, was commenced yesterday by Professor
Tyndall, the subject this year being " On heat
and cold." In the exposition of the phenomena
of heat Professor Tyndall considered them as
being produced entirely by the motion of particles,
and that heat is by that means actually created, in
opposition to the former theory that the sensation of
heat is produced by the concentration of the matter
of heat always existing. lie commenced by explain-
ing the process by which sensation is conveyed to
the brain by the action of the nerves ; using as an
illustration a row of solitaire balls, for the purpose
of showing that an impulse given to tLe end ball is
transmitted by imperceptible vibrations through the
whole number, which remain unmovable, whilst
motion is communicated only to the last ball of the
series. The production of heat by friction was at-
tributed to vibratory motions among the particles
of the bodies acted on ,which motions, though invisible,
are supposed to be sufficiently energetic to generate
heat. Several illustrations were given of the produc-
tion of heat by friction, commencing with the common
experiment of rubbing a metal button on a piece
of wood, by which means a sufficient amount of
heat is generated to feel painfully hot when the but-
ton is applied to the face. Some ether was put into
a small vertical metal cylinder, and, when turned
rapidly round by a wheeling table, grasped with a
piece of flannel, the ether boiled and forced out a
cork inserted into one end of the cylinder. Some
pieces of fusible metal were next put into the cylin •
der, and became melted by friction in a similar way.
A pair of the wooden sticks by which the Kew Zea-
landers obtain a light by rapid friction were also
exhibited,but not successfully experimented with, as
the rapidity of action required is greater than can
be given by those not well practised in the art. The
heat proficed by combustion was also attributed
to the rapid percussion of particles ; the burning
substance, according to the view of the generation
of heat, attracted the oxygen of the atmosphere
towards it with so much rapidity as to create
the heat given out during the process. Professor
Tyndall endeavoured, with much effect, to impress
the nature of this action on the minds of the juvenile
portion of his audience, and often called on them to
bring their imaginations to conceive how the effect
wrs produced ; but it may be doubted whether he
succeeded in giving a clear idea of this theory of the
production of beat by combustion, though he
illustrated it with many well-contrived and brilliant
experiments. The burning of a steel watch spring
by an oxyhydrogen jet, the increased brilliancy of
the action when the ignited steel was plunged into
a jar of oxygen gas, and the combustion of iron-
filings thrown into a jet of hydrogen, were all at-
tributed to the percussion of the particles of oxygen
drawn to the igniting body with great rapidity.
The extension of bodies, especially of metals, by
heat, was shown by several experiments, iu one of
which a brass and steel bar, placed horizontally,
were so arranged above a row of jets of flame that
when expanded by heat they brought into action by
contact an electrical current which ignited a jet of
ga4. This effect of heat was not very clearly ex
plained, according to the hypothesis of vibratory
motion. Another experiment, which Professor
Tyndall said was the most delicate of the kind that
had ever been arranged, exhibited very distinctly,
by means of the reflection of a small mirror at-
tached by a wire to a bar of lead, the extension of
the metal when only breathed upon. This was the
last experiment. In the next lecture to-morrow
the measurement of the effects of heat will be the
subject. Notwithstanding the very unfavourable
state of the weather the body of the lecture-theatre
was completely filled.

The Marchioness Conyngham has arrived in
Chesham-place from visiting the Marquis and Marchioness
of Hastings at Donnington Park.