The evening telegraph. [volume] (Philadelphia [Pa.]) 1864-1918, 1867-03-07

| flames 70 unite and form for an instant a flame
Of the ordinary shape. By slight variation
Of the experiment, the two side ilames dis
appear when the whistle is sounded. and
central tongue Of fame is thrust forth in their
stead
passing from iish-tail 70 a bat's-winp
! burner, / obtain this broad steady flame n
is quite insensible TO the loudest sound which
/ would be tolerable here. The flame is fed
from this gas-holder, which places a power of
pressure at my disposal unattainable from the
gas-pipes Of the Institution. turn on more
gas. The flame enlarges, but II is stll insen-
\ sible to sound. enlarge II still more, and now
~ Ia slight futter of its edge answers to the sound
No the whistle. Turning on a little more gas,
'l}and sounding again, the jumping of the flame
'tds still more distinct. Finally turn on gas
until the flame is on the point of roaring, as
flames do when the pressure is too great now
| sound my whistle; the flame rOars and thrusts
! suddenly upward eight long quiyering tongues
strike this distant anvil with a hammer
the flame instantly responds by thrusting
! forth its tongues. Another flame Is now be
| tore you. IL issues from a burner formed
OF ordinary gas tubing by my assistant. The
hame is eighteen inches long, and smokes CO.
| plOusly. | sound the whistle. the flame falls
| to height of nine inches, the smoke disap-
pears, and the brilliancy Of the flame is aug
mented. Here are two other flames, also
! issuing from burners formed by my assistant
~ 'Ai'iiA - lNAlb8 HtIdlkHNf Nlil hIlNkls
the other is short, forked, and brilliant. /
sound the whistle; the long flame becomes
short, forSed, and brilliant: the forked flame
becomes long and smoky. As regards, there
tore their response to the sonorous waves, the
one OF these flames is the exact complement of
the other. Here are various fiat flames, ten
inches high and about three inches across at
their widest part. They are purposey made
forked flames. When the whistle sounds the
plane OF each flame turns ninety degrees
round, and continues in its new position as
long as the whistle continues to sound. Here,
again, is flame of admirable steadiness and
brllllancy, issuing from n single circular
orifce in a common iron nipple. whistle,
clap my hands, strike the anvil, and produce
other sounds; the flame is perfectly steady
Observe the gradual change from this apathy
to sensitiveness. The flame is now four inches
high. make its height six inches; it is still
Indifferent. | make it ten inches a barely per
ceptible culver responds TO the whistle |
make it fourteen inches high, and now il Jumps
briskly the moment the anvil is tapped or the
whistle sounded. | augment the pressure: the
flame is now sixteen inches long, and you OBJ
serve quivering which announces that the
flame is near roaring. increase the pressure:
1t now roars, and shOrtens at the same time to
height of eight inches. | diminish the pres
sure little; the flame is again sixteen inches
long, but it is on the point of roaring. II
stands, as 1t were, ON the brink of a precpice
The whistle pushes it over. Observe, it
shortens when the whistle sounds, exactly as
1t did when the pressure was in excess. The
sonorous pulses, in fact, furnish the supple
ment OF energy necessary to produce the roar
and shorten the flame. This is the simple phi
lOsophy of all these sensitive flames.
''The pitch of the note chosen to push the
flame over the brink is not matter of indif-
ference. | have here tuning fork which
vibrates 256 times in a second, emitting clear
and forcible note 1t has no effect upon this
flame Here are three other forks vibrating
respectively 800, 3S4, and 512 times in a
second. Not one of them produces the slightest
impression upon the flame. But, besides their
fundamental notes, these forks can be caused
TO sound series of over notes of very high |
pitch. I sound this series of notes. the vibra-
tions are now 1900, 1000, 2400, and 5000 per
second respectively. The flame jumps in
response to each of these notes. the response
to the highest note of the series being the most
prompt and energetic of all. To the tap of a
hammer upon board the flame responds; but
to the tap of the same hammer upon an anvil the
response is much more brisk and animated.
The reason is, that the clang of the anvil |
is rich in the higher tones to which the flame |
is most sensitive. Here again is an inverted
bell which cause to sound by means of
fiddle bow, producing a powerful tone. The
flame is unmoved. l bring a half-penny into
contact with the surface of the bell; the cOnse-
quent rattle contains the high notes to which |
the flame is sensitive. 1t instantly shortens, |
futters, and roars when the coin touches the |
bell Here is another fame twenty inches |
long | take this fiddle in my hand, and pass |
bow over the three strings, which emit the |
deepest notes. There is no response on the |
part of the flame. / sound the highest string; |
the jet instantly squats down to a tumultuous |
bushy fame eight inches long. have here
small bell, the hammer of which is caused to
descend by clock-work u hold it at a distance
OF twenty yards from the flame. The |
strokes followed each other in rhythmic sue
cession, and at every stroke the flame falls
from height of 20 to height of inches.
The rapidity with which sound is propagated
through air is well illustrated by these eX-
periments. There is no sensible interval be-
tween the stroke of the bell and the shortening
OF the flame. Some ofthese flames are Of mar
yellous sensibility, one such as is at present
burning before you. 1t is nearly 20 inches
long, but the slightest tap on a distant anvil
knocks it down to s. | shake this bunch
OF keys or these few copper coins in my hand;
the flame responds to every tinkle. / may
stand at distance of 20 yards from this flame;
the dropping of a sixpence from the height of
couple OF inches into hand already containing
coin, knocks the flame down. l cannot walk
across the floor without affecting the flame;
the creaking of my boots sets it in violent
cOmmotion; the crumpling of a bit of paper
or the rustling of a silk dress does the same;
it is startled by the plashing of a raindrOp;
speak to the hame repeating few lines of
poetry; the flame jumps at intervals, appa-
rently picking certain sounds from my utter