National Republican. (Washington City (D.C.)) 1872-1888, 1872-12-06
PROF. TYNDALL.
ms SECOND LECTURE.

An Immense aud Cultivated Audience.
The subtitle gfta OF the me- Ms dirinior never
Illuminated the pathway Of humanity, proving II
onward and upward, with more direct and force
full rays than those which shine before all the
thinking world In the works Of such a scientist
a. Professor TyndAll, bringing the light which
we call science to eliminate new facts, new
meanings of the Great Creative Mind; adding
new wonders to his glory and new henents TO the
uses Of manki "a. The intellect which searches
among the irnumemble mysteries which sur
round the conditions Of our being and discovers
adltiunp! laws AMI missing links In the great
Of II more accurate and more eNtensiye-ls q
beneiactOr Of his race and Of coming time as well.
knowledge, which IS power' anh alone gives e,
such heneiactOrs, and the world Ia glad to ait at
I Ell feet while mind enslayes nature and makes OF
ne elements servants to prove the great and new
IDEAS which are to he stepping stones to higher
things" yet, and shine as added lights to aid In
the limitless advance Of human comprehension.
Professor TyndallA audience last evening was
a larger and even better one than the nrst.
Many had to stand for want " room, and from
nrst to last the closest attention was given to all
the great teacher had TO say.
lie commenced his lecture with the perform
ance Of two or three experiments, the first called
the water prism, for the purpose Of showing re-
fraction by water and color and this color was
neutraliZed by glass prism placed In an oppo-
site direction. II was all for the purpose Of II.
ustratlng the action Of lenses and their Corrcc-
ton for chrOmatlsm. The same prism was then
used to show the greater dspcrsive power Of
bl-sulphide Of carbon, and by II q much longer
spectrum was thrown upon the screen.
Prof. Tyndall then said, In substance:
We might vary and extend our experiments
Indefinitely, and they certainly would prove Us
TO possess a wonderful mastery over phenomena,
But the vesture Of the agent only would thus he
seem and not the agent itself. The human mind,
however, Is so constituted AMI SO educated ~
regards natural things that II can never rest
satisfied with this outward view OF them. Bright.
| ness and freshness take possession Of the mind
when II IL crowned by the light Of principles
which show the facts Of nature to lie organlcallN
| connected.
Lei ns, then, inquire what this thing Is that we
| have been generating, rejecting, retuctlng AMI
decOmposinR. In doing this We shall learn that
the life Of the experimental philosopher Ia two
! fold He lives In his vocation, life OF the
Senses using hands, eyes, aud ears In expert
ments hut such a question as that now before
us carries him beyond the margin Of the senses.
lie cannot consider, much less answer, the ques-
ton, what Is light, without translating himself "a
world which underucs the sensible one, anI
out Of which, In accordance with rigid law, all
optical phenomena spring. To realize this suhsen'
| alhle world, the mind must possess q certain pic
torial power. II has to vlsuallse the invisible,
! It must he able to form definite images OF the
| things which that snhsensihle world contains;
| and to say that II such or such state Of thing
| existed In that world then the phenomena which
| appear in this must grow out Of that state Of
! things II the picture he correct, the phenO-
mena are accounted for; a physical theory has
/ been enunciated which untes and explains them
! ALI lIlt fOuttnllNU vi lWlH NWNNlN llllNlltH lnf
| exercise Of Imagination. We have to Invoke II
| In order to get anything. Without u we CannO
| take q step beyond the bourne Of the mere anima
! world, and by Imagination IL meant disciplined
power. II Is one Of the objects Of these lectures
/ TO disclose the invisible sources OF phenomena
! Before Newton began to deal with light he wa
acquainted with the laws Of elastic collision
which all have seen illustrated on the billiard
table In his previous knowledge hts magma
/ ton found material for theoretlc images. lie
] mad only to change the magnitude Of the cOncep
/ tons In his mind to arrive at the theory OF thu
emission Of light. Newton supposed light to con
! slst Of elastic particles OF Uncomfortable minute
| ness, shot out with ncOnceivahe rapldlty by
| luminous ho,lies. Such PARTICLES, implnglng OF
! with the law OF elastic collision. His conceptions
| regarding the nature flight were also influence
by his knowledge OF grayltation, lie could no
at that time form an unfettered Judgment on tn
nature Of light. He saw In refnctiOn the eNer
ton Of an attractive force eNerted on the part
Giles Of light. Dropping vertically downward
! towards the earths surface the motion Of bod
IA accelerated as 1t approaches the earth. Drop
ping In the same manner dOwnwaTds on hOrt
ZOntal surface Of glass or water the velOcity o
light particles, according TO Newton, was &c
the root OF matters, we determine by deduction
what are the phenomena which must Of neces
thus deduced agree with those Of the actual worl,
1t Il a presumption In favor OF the theory
Like the scriptural GIFT Of the Spirit no man cal
tell whence II Cometh. The passage from fac
"
Joy. Those who have experienced this pleasur
understand the action Of Archlme,les, when h
quilted the hath and ran naked through tn
streets Of Syracuse. NewtOns theory was fOun
competent to explain a great number Of facts
and It's author made II account for all Of them
He so far succeeded that mon 50 celebrated 4
LAplace and Malus, who lived I'LL 1872, and Bio
and Brewster, who lived Till our own time, wer
found among his disciples. SIN one or tw
names were recorded against the emission
theory. II was supposed that light, like sound
alWaNl la . ha aFittfN NJ uNHnf NafNFtn
This conception was advocated by the astrpn
nmer Huyghens and the mathematician Euler
Newton's authority bore them down, IIuyghen
and Euler did not possess sufficient data 10 prov
themselves In the right,
In the year lTI9 was horn at Mlyerton, Il
SOmersetshire, one Of the most remarkable me
that England ever produced. lie frst penetrate
the ohsCurity which had for ages yelled the hlerC
gyphcs Of Egypt. lie succeeded In establlshin
the undnlatlng theory Of light. This was ID
Thomas Young. lie excited the wonder Of hi
contemporaries, hut they were unable to fOllON
him. His rights were restored by Fresnel an
ATagO. Carlyle refers to remark Of NOyali
that mans self-trust Is enormously increased tn
moment he finds that Others believe In him.
The following experiments were then very az
tistiCally and beautifully performed, and /
which the Professors assistant, Mr.. CUttril
came In for full share Of praise. First, Their
was the sounding Of a tuning fork and Its a0tio
upon the air, breaking II into waves, and the
followed what the Professor called the lOnR,tu
dlnal pulse on the screen, for the purpose &
fork Is sounding; then two tuning-fOrks wer
sounded In unison, and one Of them being lOAde
, With a small weight, beats were Obtained; AM
after that was the experiment OF the Optlca
expression Of the vibration Of 4 single fork
beam Of light was sent from the lantern on
mirror on top Of fork, which reflected hic
! on the screen a single spot Of light when n
= fork Is at rest; when the fork Is vibrated It
, drawn into line. A beam was then received frOl
the vibrating fork upon mirror and reneute
on the screen, which drew the line out into
| ginuOus line Inv oscillation Uf the miFFDF IN
optical expression Of beats followed, made hy
+ combination Of vibrations Of two fOrkI rehccte
upon the screen.
The next experiment was the extremely beap
tlful one Of the hand syren. beam Of light frOI
the lamp, through holes In the syren was fOcusC
upon the screen, and then followed the alternal
appearance and extinction Of the aperture
When the Images Of the aDeTtures on the sCree
are continuous, the SOUND Is continuous; Us lon
a. there Is any break Il Is only nutter. III
same beam was received upon rotating mirTl
J and reflected upon the screen. Then was show
from q spectrum by one prism the diiIereI
lengths Of waves Of different cOlors.
The Professor lnCidly stated the principles 20
eTning the Interference Of light and reflected Il
} COlOrs Of oil and water on the screen, prOduCiI
lovely zones Of different cOlOrs, and then can
the exciting experiment Of rejecting on u
screen the cOlOrs Of the soap bubble. lie tn
deduced the periOllcty Of varying nlms an
I again followed up by u display on the screen
, Newt0n,s rings, from perfect apparatus, In re-
: hlne and white light.
spectrum was thrown upon the SCREEN n
! waves Of the cOlOrS Of which were for the re-
36gls In one inch for orange, 1891; for yellow
I6,O34; for green, 9,B09; for hlue, h3,4Il; for Il
diRO, 1850, and for violet, the extreme, O., O.
T waves In an inch.
: The refncti0n Of colors was shown from fine
! ruled glass projected upon the screen.
! All these experiments were great successe
The next lecture will he delivered saturday eve
Ing, December I.
q The Fire Department.
In common with the balance of hOrsRs in M