The Dorset County Express and Agricultural Gazette.
Dorchester, Dorset, England, 1868-02-18 00:00:00

LET THERE BE LIGHT.

On Wednesday evening Int Mr. Joseph Drew delivered
his lecture, " Let there Its Light,' at the Literary
Institute. The lecture hall was literally crowded with
an intelligent and highlp useportable audience. His
wonhip the Mayor presided on the occasion, and made
a few brief remarks, introducing both the lecturer and
hie aubjeet. The following will be found a hare outline
of the scientifie facts embodied in the lecture—the
literary prices and eloquent perorations with which the
lecture abounded are from neencity omitted, and we
may say that those who feel an interest in the various
phenomena connected with this laws of optics shoald
avail theniaelres of the opportunft7 of hearing Mr. Drew,
should he repeat his lecture in this town.
In • prologue to the lecture, Mr. Drew stated that
although the whines of optics was intimately composted
with the lecture be was about to deliver, yet he was
not going to give • scientific treatise, but merely a
popular lecture that might be acceptable to those who
had neither the time, opportunity, nor iodination, to
study abstruse scientifie troths. Hs should conse-
quently refr. In as much as possible from employing
scientific terms and technicalities, "Let there be
Light !" We were all familiar with thie proclamation
of the great Creator; this fiat of omnipotence. 111 the
Massie account it was recorded that light was called
into being on the first day • hot light existed myriads
on myriad. of years before :be first few grains of misty
matter formed the lindens of this earth. Before time
was, if it were possible to grup the fulness of tho
expression, the Great Aichitmet of the Universe renned
am f,,n of majesty and a. o.niposeut as now. mad when'
Jehovah retrial light mast be abundant. One see
was not the primer? Douro, of light. Other suns such
an ours rolled in span, regulating the movements and
controlling the Motions of planets revolving round
their respective dins, and thee. suns, like ours, were
supplied with light from the eternal fount; and then
suns dietributaid light in proportions varying with their
sine. But comparatively • few years back this globe
was • thoreless ma of fire; and few yearn later it was
tenantod by gigantic mammoths and • luxuriant vegeta-
tion, and but • few y. are later still our first parents
were mined. Bat back, bask in untold ages, other
worlds existed. other suns shone, other belay
worshipped the Creator as we now do. The Ist chapter
of Genesis did not give us an amount of the creation of
light itself. The "first-day" meant the first period sl
time; but what was the duration of that" period "? The,.
was no ...station to this problem; the rocks bore no
testimony, and all human calculation failed, as all
human efforts must fail, when attacking the citadel of
the infinite. "In the berinning" God created light,
and pronounced it "good.'' Following out the Mosaic
acomuit we found it was not until the fourth day that
our sun wee created- We had incontrovertible
evident., that our sun was not the primary
mourn of light, though light did not reach
this earth =tit its creation. Light was to families
that .we seldom or never paused to admire the
wisdom and power of the Creator who bad called this
marvellous agent into existence for the special comfort
and enjoyment of his creatures. We bad been so
accustomed to view light as part of the material oreatim
that we did not dwell in its composition, nor it. effects
on animal 11.04 vegetable lite. We did not admire •
phenomenon that was so common; we now the effects
of light, but never asked how these things were brought
about? What was light? It was a fluid, and so
Important • part did it play In the animal economy
that if deprived of its existence we should be blind—
the eye would be useless. Planta would linger on the
smith for • time, but would not thrive—they would be
blank and sterile and colourless, and would become
chansrd in their physiodorganisations. That *timing-
km influence that enabled planta to absorb csrbon and I
throw off oxygen gamin the day-time would be Int. The '
properties of li ht formed • subject of much specula-
tion amongst ancient philosopher., but no satisfactory •
113pothesis was found until Sir lona Newton gave to the
world what was termed the ourpuseular theory. Os
this hypothesis light was supposed to he composed et
small luminous particles, which striking against the eye
ptoduced sight, analogous to particles of perfume ,
coming In contact with the olfsetory nerves madmen
the power of smell. The divisibility of matter wee ins
of the most interesting and subtle problems of sciemos.
A grain of musk introduced into a classed room,
and allowed to remain long enough, would so
dnivate itself as to fill the whole room, and so
minerals oinld be rotund to aulphistau then dissolved
In water, and the process of divisibility carried on to an
alum.% boandlne extent. (ht ths divisibility of particles
of light was Newton's corpuscular theory based; but
that had no. been almost entirely abandoned in favour
of the undulatory theory, which allied itself to Use
principle of sound, *a :lir J. Newton's theory allied
It-elf to the principle of sawn The undulatory Unary
maintsined that light is • fluid composed of particle%
which ernan..to from, luminous bodies, and an refle
from non-luinincpas bodiea. Muir scientific men weight
to arcinnt for all the effects of light from the vibrations
of ether on the eye. There were vsrietin of wane
molecules, each h,ving properties of its own, and whilst
In it. itiairi,y the common plienomeonn of light was
pro luoed, still each ray cootainod within itself beat,
colour, light. and electricity. Each ray might be
divickd into its actinic, luminous, and caloric parts,
and each was so distinct Vast the ens could not be
mistaken for the other. H. proposed dividing W. sub-
ject under three beads, first, to prove that light prociesda
from luminous hod.., and are rifiected from non'
luminous bodice; second, to sm.w the
bbeleey between
light sad sound ; nod, third, to prove that • beam of
light may be analysed and separated into its maiposent
Light proceeded from laminas* bodies in
air.", jams, and paned through the attenuated Sher
until ressmng our atmosphere, whim it became diffuses&
Tin stuodial was always ammot from the fact that the
sun's rays cams in direst, not oblige* lines, and this was
further proved by the fast that the first cobweb interns&
leg arey would throw as firm and correct • shed*, can
ortlol4le. Light travelled through t:i• attenuated
medium of ether at the rate of soma 300,060 miles per
second, and bad this medium not been so mach mon
subtle than our atmosphere we should not me the son's
rays until some months after it had rims. Ether tied
the intention of air am water filled the spaces betwen
wholes of seed. Now luminous bodies relented the
light they revonal, but when the soothe of light was
removed they bosoms invisible. Ether MS the con-
necting link between world and world ; it existed army'
where, in the blast furnace and the block of Ice; neither
temperature nor force could destroy it, and It conveyed
the particles of light to oar vision. By the aid of optics
volcanoes wen discovered in the mate's surfaces, snow
sapped mountain. wen in Mars, and the surface of stare
of the 12th magnitude made out by Lord Boss's telstecopu
But man with all his knowledge of mean could not
ritual that little filament, the optic wry°. The
lecturer then, In senrianos with the argument of Sir
David Ben ester. epseulated oaths possibility that then-
habitants of other wort Is might have their optic rimless
so formed as to be able to en infinitely farther Mose
°armless. In support of this eaniesiure he inhumd
the visions throe sew when sight was sublimated the
approach of death : and the case of the early
mhos, glimpses of Heaven rendered fiheedhe
sensible te the agonise of the Make. Being, In Wier
spheres might be able tons what transpires'in this glohi.
and if so, no far away were nem of them, that allowing
the picture to travel upwards at ths rate 91 12 Milian
of miles per algae, the seem of the expellee of
.idem end Eve Ins sh• prim ol idea Todd hem

mob mew oohed thus' and the inhabitants of the
den of the twelfth mapitale woeld now be whammies
all the Weida* arenested with the Uslagual Dahl& I
IL--The *melon between sound and light eowelsted
In their both being transmitted by neduatotry
through ether. If • *Joao is thrown into the water
• number of water rays will circulate sand tbe disturb-
ing agent for some time in concentric movement, and
vibration striking against the air, produced ripples in
the atmosphere similar to the rippler made by a slow
throws) into the water. Now light wee propagated in
the sumo Inelaner, • lamp or flame of fire kept lip
• steady wihratioa se tire surrounding air, but wither
all lenna use nod wanes moved at the same speed, for
If so there would be no variation In Douai og Otiosity,
limed travelled wording to the °stew, and different
etiours of light undulated at various rasa Without
sir there would be no pound, for if a bell were plead
In a vacuum, the bell might be observed to move but
there would be no good. Echo was produced by ironed
—wanes falling on a ruartanee of ocionve formation, •
multiple of concavities produced • multiple of echoes,
and et Woodstesit, eseez Oxford, oho repealed hall no
less than 50 times In various directions, owing to the
&wearable 414,6101 es el the Luella. These principles
also applied to light, hones the undulatory theory now
eo
generally adapted. Light, like sound, might be
harmonious or otherwise. Although the prim ifi'm
'even colours to • ray of white light, yet there are ovli
three primary ones whisk Wending, produce seven.
red. 'mend% Yolk*, gyss., blue, Indio, and yield.
Colour was produeedbT bsdlss absorbing all ooloure
inapt the wow they roiled, bat embelasiese
all colours were white and there •Vb w
rigag.
colours were lime. Mated light ; in
accordance wills the law of aeon and reeelkt=
set the molecules ie motion, and the whole wee ;
but so cereals were the laws obeyed dui no goof melon
*mods tn. The analysis of light. Anal
means ysis
meant separailea, and it war Swaab,t7
prissi to 'sparse* the eerie's' Pette '""
a ray of white light. The ezpiniment might be trie.d.
ID this manor. Dear ,room. bet thtensh etie.mm
neaten allow a ray of
and so timP;sa,r on=i),
ar Pk" gil aaa slild'--.;;;Lig;- hall
the ray of whits light "
Into the
ainC,_ lighting. 0010grlUgi
Tbe analysis was thou
would be found thristrild 4ad.
hare.
eherand, sad eleetrical the primary
swami.
omplete, and berg we awa
or light. This was proved by aliaaiall was ray re
prismatie light (say blew) to Path tilltengh • seeend. P_lhns
sndfal ea a amen ; oh s blue Toy would still tie blue,
and thee we herweet the analysis was somplete in the
first Wiahle. Now, to resolve the prientatie colours
to the origiael ray of while light, ith the rage estiveryc
is • meow mirror, and the experiment would be
emnpleies. light was grouped oder three bade, the
calorie, or beetle', the Wellcome, and the actinic, or
themical New heat, like light, ocieupied space, and this
odd he tested by welshing Ito inithenoe on int. tab. If
• bar of iron be heated it would erpand according to
the hese to white it an, subjected, and when heated to
mess the heat would forces each atom of iron beyond
the attraction of atom for atom, and this was called the
melting of iron, and this was simply owing to the
mixture of heat and iron in suit proportions as to
prevent the particles of iron I .ding together. The
lecturer than went on to show that beat pervaded
everything, and to enumerate some of the Morino we
owed that agent, and traced in an highly interesting
manner the action of heat in the proses of ferments-
tiro A brief referent* win then made to the spectrum
analysis, by means of which it is shown that the sun's
photosphere wes due to the pretence of sublimated
metals in an active state of combustion. Beads; the
revelations of the rpectrum &wields we had been
further helped to our investigations of the
constituent elements' of celestial bodies, by analysing
meteorite stones that had fallen on the earth. The
chemical roe of light also exerted great legalises on
all organic substances. The various shentiael properties
of plants, ate., were due to this aurae. In deviant
pools, and accumulation' of foetid matter, this principle
was very active, and the wind carried malaria and
Plague from Boob places, and those who fell the first
victims to the poison were the,. who bad lost most of
their inherent electricity. After an illusion to the
*canoe of photography, due to the action of light on
themieally proposed surfaces, the lecturer speculate i
on the possibility that all the deeds and scams door
whilst on earth might be photographed in the" Book
of Life," on which we should gam on the great Day of
Judgment. The lecturer wound op in an eloquent
peroration, and sat down amid the applause of an
audieece.
Dr. horhead said
'There are more things in Halo and earth
Than are dreamt of In your philosophy,"
so said Shakespeare ; and he was sere if the poet weld
have only heard the lecture of to-night he would have
mob regretted having been doomed to live in the
dark ages. He bad been greatly gratified whilst listen.
ins' to the interesting and eloquent lecture, and in con-
clusion begged to move • hearty vote of thanks to lit.
Drew.

This proposition was seconded by Mr. Landis and
heartily carried.
A cordial vote ot thanks to the Chairman concluded
the proceedinp.