The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1836-12-02 00:00:00

TAE LIVERsPOOL STAI4bARD.

carbonate of lead and acetate of lead- simultaneously formed.
The vinegir undergoes decomposition, and in the course of a ,
few weeks we haves crust of the carbonate of lead formed upon
the metallic lead, but it will take
,three mont*to convert, the
whole sheet of the ordinary thickness into white lead. When
a thick film is formed upon the lead it is removed, in order to
expose_ a fresh surface of metal to the action of the vinegar. The
operation of removing this crust was formerly destructive to
health, inasmuch as the workmen were generally afflicted with
what is called .t he painter's cholic, which caused them contrac-
tions of the thumb, the elbowS, and knees. This arose from the
unscientific manner in which they removed the carbonate of
lead. In removing the lead it is said that one pot in twenty was
broken, besides which the lead was brushed off, by both of which
circumstances it .is obvious that a number of fine particles of
lead wonbi mingle with the atmosphere and enter the lungs of
the workmen. A simple plan is now adopted by which, this
complaint is prevented,—it is merely the removal of the crust
of lead under water. _ _ _

Verditer is another of the pigments produced by chemical
affinity. It is both blue and green. The green Made of the
waste nitrate of copper, which the Sheffield manufacturers have
left in the process of recovering silver Flom waste' cuttings of
plated copper. By adding lime to this nitrate a green colour is
produced, which may be changed to blue by the addition of an
alkali.

I.ECTURii V.

On, Wednesday evening Mr. Hemming,, introduced and ex-
Plained the various modeS of producing artificial light, prepara-
tory:to which he.expOunde'd the general properties of natural
light. The attendance was more numerous than at any previous
lecture.

We have now to consider the different modes of obtaining and
supPlyiag artificial light. As the physical properties of light
produced artificially and naturally are similar, it might' be as
well; in therfirsts'itlace, to say a few words respecting them. The
first question that will naturally arise is, " What is light ?" Is
it a material substance, or is it a property of matter, or is it
something as distinct front matter as sounds frern'the ody pro-
ducing them ? There have been two theories propounded on
this subject, both of which have been. ablY'supported. The first
of these;'Called the corpuscular theory' which was advocated by
Newton and others, is losing ground ; :whilst the undulatory
theory, supported by Eniers and a•number' of eminent philoso-
pherS, is daily superseding it. According to Newton, and the
corpuscular theory, light is matter throwii from the sun in minute
alled rays, each of whiCh proCeeds in: a rectilinear
directien, and'tEditie substances on which these particles im-
pinge bechMe luminous by repelling them. If this. be correct
it is diffichlt to obtain an idea of the nature of, Erray of light,
becauseit ii a lawittinachanics that the momentum with which
a tartly will impinge' upon another depends upon its size and
velocity:.' Thus,' for (maniple, a cannon-hall is a more destruc-
tive wealirin-than the battering rani' sof ancient Warfare, merely
bedatiSe its velecity is greater. If we suppose a battering rain
to weigh'looo pounds, and toi swing to and fro with the velocity
of tea feet in'a second of time, tile weight multiplied into the •
velocitY will give an idea of its force. But if a cannon-ball,
only 'weighing ten pounds,' Move with a velocity of 1000 feet ill'
a second, the'same effect will produceds-Lthi force Will be the'
same. That a superior momentum is created 'by superior velo-
city is a fact well known to Most persons.- If we throw a nius-
'ket-balf against a board, we shall merely make a-slight indenta-
tion upon it; but if the same ball be dis'eli rged frtini die mouth
of at musket it will make a hole through the hoard. It must 'be
evident that the ball, in either instance; will weigh the same,
and therefore that its greater force is simply occasioned by its
being 'impelled with a greater velocity. Whether the human
arm he`moved quickly or slowly' its weight is the same, but not
its tlirCe.' Accordingly in pugilism it is well k noire that the
force of The blow is in-propertion to the velocity with which the
map strikes. Thus a sinal! 'a Weak, or a light man Will produce
a greater effect With a-quick I-tuition than a "powerful inan with
a slew motion.' Now, according to NeWton, light: is composed
of small particles of rays of light, and these particles move at
the rate of 2000 miles in a second of time; therefore, as mo-
ntehrhiri is eaeal to the velocity; multiplied by the weight, and
as this: 'velocity' is infinitely greater than that of any body ex-
isthigillidir this earth, the weight Of the particle or ray must be
inconceivably minute. Let us suppose fur the sake of example,
the velocity to be, in round numbers, two millions of imes
greater than a cannon-ball. If, then; the velocity of light be
this; it follows as a natural consequence • that, if.-a: ray sof light
were aarlarge as• the two millionth', pert of a grain•'.of sand, it
would produce as great an effect as that of a grain otsand forced
fi=ont a cannon mouth. We have, however,-no better reason for
supposing that lig4t is a material body thanthat sound is a ma-
terial body. If a glass be struck with a finger a distinct sound
will be heard, but we .are not to suppose that when the glass is
struck that any particles of it are detached in the operation•and,
fall. upon . the tympanum ,of the ear. It would. be absurb
to suppose. that this is the case, and yet, we have nu better
reason for supposing that •light is produced by small par-
ticles of. matter impinging :tipott the, eye. • According to the
undulatory theory we are told that light is produced like sound,
that the whole of the universe is filled with a certain high's-
attenuated and subtile fluid called ether, which is not light of
[itself, but produces light when thrown into" vibraticin by the
peculiar action of a luminous body. In short,".th-at this ether is,
,'With respect to light, what, our atmosphere .iss with respect to
sound—if neither of .them existed then there would be neither
light nor sound. The air is thrown into a series of undulations
by the voice, and 'produces sensations of sound. Tfiese
undulations are simiiar, to thosepaloalde and visible waves pro-
dueed by-throwing a pebble into water'' which proceed from the
pebble as from a centre until' they' reach the verge, of 'the water:
We may suppose that light, is, produced in a similar manner,
excepting that its waves proceed in every directien,*not merely
horizontally, but laterally; vertically, add in every possible di-
rection. According to Neivton's theory the different colours
constituting a ray of light are seven, or at least three,' out of
which the remainder may be produced, 'and that these colours
are caused by a difference of size in the
.particles. According
to the uudulatory theory
,the differeuce of colours proceeds from
the different velocities of the waves of light, some of them tra-
velling swifter than others, • if it be difficult, to conceive what
may be the size of particles of light, it is eqUillY,diffieult io con-
ceive how infinite these undulations must be, or how rapid they
may be, amounting as they do to billions of waves in a second
of time. Newton was the first to effect the decomposition of a
ray of light into seven different colours. He received it through
a hole in a window shutter, and refracted it through'a triangu•••
far prism. These seven rays were again attempted to be de-
composed, but were found incapable of further decomposition.
It is supposed that these seven. primary rays are composed of
three rays—red, yellow, and blue. It is therefore by the bar-
moniourbletiding of these three rays that the seven different
tints are produced. When these are' not decomposed they'af-
ford a white libt.. Black is an absorption of light,, or a cepa-
citffer absorbing a portion, and a body always appears of that
colour which it is most averse to, or of that colour which it re
fleets. In reality there is no substance which we can see by
any light which will be exactly either black or white. There is
not auy substance capable of reflecting or absorbing all the' co-'
lours. This may be'proved by exPeriment. Thus a coat which
appears black in ordinary light will appear white if a much
greater quantity of light be thrown upon it. A binning glass
will effect this by concentrating the light upon a particular por-
tion of the coat. In like manner if we direct the focal rays of a
similar glass upon white paper, we shall find we were very much
mistaken in supposing it previously to be white. Light is re-
fracted as it passes through different mediuma. We mast suppose
that light passes in a rectilinear direction front the sun to the
confines of'pur atmosphere, but that it will there be bent out of
that_ course in consequence of the medium becoming denser,
and that it will beCome more refracted for this reason as it ap-
proaches the earth. The earth is besides constantly moving.
On account of these two circumstances we never see the sun or
any celestial body in the true position. A ray of light occupies
eight minutes and thirty-two seconds in its passage from the sun
to our earth.. It was formerly supposed that the phenomena of
light was instantaneous, that the instant it was transmitted from
the sun, that instant it passed to the earth. The: error was dis-
covered by observing the different periodi of 'tittle in which Ju-
piter's satellites emerged from his shade, according to the va-
rious pliCes of the earth in her orbit. By this means we find
the time that light takes in travelling from the sun to the earth.
Owing to the refraction of light we see the sun eight minutes
and thirty-two seconds before we otherwise should be able when'
it rises, sand'for the same space of time after it has actually set.
This, Mr. Hemming beautifully illustrated by sticking a num-
ber of wafers at different heights in a bowl, and desiring the
spectatersle count the nuinber they could perceive ; he then
tilled the bowl with water, w hens a much greeter numberof
let's veuld be distinguished, owiegs-to, the, different: refractive •
powers of the air and water. Mr. Hemming then explained the•
causes of the rainbow, for the discovery of the theory of which,
he said we were indebted to Newton. -The intensity of light is'
inversely as the square of the distance, not that•there is less
light at any given distance, but that the saute quantity of light
is spread over an increased space. •

- ,
Thus much respecting the physical properties, of natural and
artificial tight.. Artificial, light in the abSenee of the sun is as
indispensable as the air we breathe, to the happiness and enjey-
ment of our variou4 senses; therefore, a substitnte•for natural
light has been sought after front tithe itnthenterial. The gene-
ral mode of obtaining it is front the combustion oecerlain sub-
stances, which by their burning produce light. We hate
nothing to guide us as to the mode by which light was that pro-
cured In ancient times. It is probable that it arose fruit
friction, for we know that wheels, forests have been burned down
by. the friction of one branch againtt auother, in a heavfeale of
wind. It is known that if the axle of a coach-wheel were not
well lubricated the box would take fire. The effects of friction.
are early learned at school. It i+ known, that if a buttihi With'
a metal head be violently rubbed such beat is produccd, that
when' the buttiM is ,;lify applied iti the hand of his next door
neighbour, it will burn hint. In saysge countries it is common
to prieluce fire by friCtiOn, by rubbing two pieces of dry"wood
together, or a cavity: is made in' one piece of wood, whilst
another piece is caused to rotate by the action of the hands.
:I:liese modes are not resorted to iti more civilized countries.
The.. most simple Mode now adopted is by the application of the
deservesiNiviWe know
k4tNi,nsitotheraee:c,
woaennseti !Ili et!. rina:tisieie:antr'ktobsixin) v iNtsh(ev‘it,h) generallyl
violent
l vobumbleonuc.ctshtat!'ne applicationtl.rottO.
the
~,,i it.
that and steel, which sparks drop into the tinder-box and Set
te couse fire to the
~
tinder, so that a brimstone match is inflamed Lou.'
but
of these sparks is not generally under Stood. In til
dOn it i+ the cominOti practice for pertons who sell these flint
,stones; - to stand iu the streets at night at ,d strike the flints
Bg"iust the steel, callitto- upon the by.estonrters, as the sparks
latte 6 eflui!nitt.tsede•ont:'a‘i%nit:,7,SlS,,:lriebVivilr—mitc I fire their flints contain.
sbulabstiantgic;)e,:g:iis.
When
thdrienl.:,ticxbihed
aeliu:
I,n)).;raitnriooknnn:tifictikthdlo6es:,,'lt.ofesrif,:
,acti portion of the de-
were the kothkies hard etiot-le
'the sante effct w6uld be
,prodiictt,..l.
ititut!lellislelt:aelatis
et'l4i;'iltClthra'utliet r6e.f.nfluaitds red but until it has-kindled
the cinder, the heat
.of which is then rendered sufficient by
inflame the hrithstone of. a match'. The usual
etr(iiployed for supporting flame, are 'fat and bitu-
minoushen we say that we burn, oil, tallow, or
wax, we speak erroneously, as they niust tetirstdecomposed
into their respective elements. and to do this the presence of
flame is necessarYy If we -were 'to apply a pteee of iron at A
white, heat, to oil' or tallow, we- should ' merely vaporize
theni. • The same 'will ' apply to ether, alcohol, or turpentine;
but when 'we apply' Warne we readily 'decompose these sub-:
stances" and obtain a• supply of light: After the discovery of
it was made the means of procuring light ; indeed
phosphorus,itotlep
sent day it it most extensively- employed on the, Cm_
of phosphorus is dissolved in a liquid; and a brimstone match
especially' in Franee, for that purpose. A' small portion
being
anent,
ens: The match is then' rubbed upon a piece of felt, when it
takes fire. Sontetinies a small tinttibe is employed, into which
a stick of phosphorus is forcibly m copressed. We have a
better hut more expensive mode of preparing phosphorus, it
is manufactured into a finely divided stare, and mixed with
magnesot or lime ; in this state it is carried in a small bottle it
tiox, and a small portion attaching itself' to a • brimstone match
when introduced, is easily ignite'', by rubbing it on any haul
stibstance. After the diScovery of that wonderful salt. chlora's,
of potash. it was extensively used in various modes for the prs-
Mellen of instantaneous. fight. ' Chlorate of potash is a eels-
pound of chldride acid and potash. Both or the constituents of
t,rilitilnocril(e !
a sendsma' all re.riureatillittitthvkaobfles't
powderedi) o:'i rte riso la) t;
sugar combustion.
with
small
we
I
quantiiS, or chlorate of potash. a single drop of sulphuric acid
will ignite the mixture. 'From this compound many very UFO,
ful instentanconslightlireparations have been made, and tie
first of t hesewis Well- litieiktit 'es' t be F rot] Ali re box.. , In stud)
vials, at thk hiitteniii (Wilhelm 'boxesti a )l/illing gilanfily of iel-
14iltrie 'add"' 4V4tkP'e4tit-lititie4Ctiti'S 6611jkill'eatoti,vwith aslirstrs,
to prevent it from running out of the bottle should the bottle ',e ,

. -
upset. The upper portion of these boxes contained nititdhei
dippod in brimstone, and then in a mixture of sugar and chlo-
rate sf potass coloured with'vermillien, and formed into a paste
with gum water. Upon these matches being introduced into
the sulphuric acid, they take firc; 'but it vies found that, after
having used the matches fur a short time, they became useless
in consequence of the sulphuric acid having a powerful ten-
dency to combine with the moisture of the atmosphere, whereby
it bccasne so dilated as not to be able to decompose the carbona-
cedes matter with sutlicieut rapidity to produce combustion.
This may be avoided by. putting the bottle before the fire for a
few hours so as to.deprive it-of the vapour. Mr. Jones, of Lon-
don. has improved upon these French matches by the invention
of .protnetheans. These matches are composed of pieces of
waxed paper spirally coiled up with one end thinner than the.
other; within the larger end there is a small tube containing
sulphuric acid embedded in a small quantity of chlorate of pot-
ash and sugar. We obtain a light by striking the larger end
witi a hammer. Now by doing this we break the tube, and al-
low the sulphuric acid to communicate with the compound, and
the waxed paper takes fire. When we want an instantaneous
light itt the' dark, a timmer" is not always convenient, and to
meat thiS difficulty Mr. Jones has supplied his customers with a
pair of nippers tocrush the tube. 'lle only objection to this
inude of obtaining light is the expense of the materials, Chid-
rate of potash is employed for various operations. This remark-
able salt has such a tendency to undergo decomPosition,*that it
will combine with other substances, and produce detonations
that are really awful. If we mix it with a portion of the native
suiphuret of antimony in a state of fine divisiOn made into 'a
paste with water and a small quantity of starch, matches made
with it, being first dipped in brimstone, will ignite with a small
degree‘of friction. It is quite indispensable that the compound.
should be Mixed in the wet state; by neglecting this precaution
&large manufactory of the matches in London was blown up..
Mr: Heniming illustrated this by forcibly triturating some dry
chlorate of potash* with' some sulohuret of antimony, when a
powerful explosion took place. The general 'properties of the
potash and antimony for making these matches are three parts
by weight of the fernier to six pasts' by weight' of the latter.
The chief cause of these matches not lighting when drawn.
thrOugh sandpaper is the weakness of the wood. InGermairy,
where iiniber is mach cheaper tha'n here, the Matches are insole
much thicker and stronger, and ignition always ensues. An,
article called a slow match is much used in this and other coun-
tries.. This, slow match is paper or cord dipped into a solution.
of saltpetre and gunpowder. It ii used for the purpose of light:
trig, the pipe or cigar, as it retains fire until the whole is con-
sumed without any flame. A slow match is.of great value in
our manufactures; it is used in mines for the ptirpoe of setting
fire, td asrain.of powder used in blasting rocks, in order that,, lm
its slow but sure combustisin; the miner may folio time to se
cure himself from the effects of the blast. The artillery in'an
employ's them to fire off cannon and other field'pieces. 'They
were formerly employed to tire off musketi before firelocks of
the Ordinary desehpiion were invented; they were either placed.
*upon tlm powder in' the touchhole by the soldier, or were at-
tached to a lock, thence called a matchloek, which 'could be
dircsetect by a trigger to the touchhole. They have heen super-
seded by toe flint and 'steel, aad more'rec'ently by the percussion
cap. These slow matches are used by the studjnts at some of
the continental Universities. These yoUnggentleinen are worse
than our. youngsters, for they Smoke in their beds, and, as it.
'would to incouvenient for them to'strike a iigbccvery time they..
awake, they suspend a piece of slow cord to the ceiling, by
which they light their pipes when they awake:
'Mr. Hemming here explained the principle Of Dabereiner's
I,inip, and cautioned the audience against allowing the pleitinilin
to be acted upon by the gas until the whole of the atiniisPheric
air had escaped from the interior, which maybe 'easily managed
by placing a piece of paper between the jet and the spongy Islas
-tuntai, lest an explosion should ensue, au instance of which he'
related, where a Turkey carpet andn'number of ladies' dresses
were spelled.. We may ignite a' piece" of Aniailini or German
tinder by means of a condensing' syfinge; but this 'is a troy -.
blesorne and uncertain operation. Another mode of 'prove ring'
light is by means of a reddish liquid conapOtind called ter chloi,
ride of chromium, which is made by distilling a mixture bf
weights of the bichromate of potash and*Common salt with sul-
phuric acid, when a gas is formed called' the ter chloride' of
chromium; which maybe cendenied in water. A drop of 'this*
liquid poured on turpentine, alcohol; ether, sulphur, or other
inflammable subitatices, will cause 'their iii`stailt ignition.
In the letture Of to-morrow evening Ali.: HrNining Kill ban=
sider the means of supplying and continuing' the'supply (Alight.

. ,
DISCOVERY IN CENTRAL AFRlCAi—Doctor Andrew. Smith;
who was sent out .by the. Cape of -Good Hope Association into
Central Africa, -has recently presented to that body a very in-
teresting .account of his travels. The expedition nnder him
consisting of 50 persons and 150 head of cattle and horses, and
twenty waggons, -which started. from Graaf Ruiet, on the :18th
August, 1834, returned in the spring of.thepresent year,. after
penetrating to the latitude of 23 deg, 21i miq. north. The mils..
sion became acquainted with members of twenty-seven tribes,
and had .information of-sixteen others, and realised a very es,-
and one ; package . dried
tensiee and valuable collection in. natural history, inclorling.lBo
skins Of new or luxe ,quadropeds, 3379. skirls of now.or ;me
Ito beesebelieved; a..,n1 that
birds, three barrels of 'snakes and Liz trds, one box of. insects,
three crocodiles, and two :skeletons, twenty-three note and rare
gales'ollnalrsi(eVrt:Pine:tilm.tlinast!', the, Hottentot race. was
e'hhaslghiniigh:t.o it inhabit the interior as
tpohritnotiss.es.i',7h9.oy
not I I•CS .than
hich,they.were told .was
fpnnaarric,ailetssmthootirre„,(4.e,nyxnita;n:ll4l(ilildiatkei.t6hs,ar,bwi
three weeks' journey to the north of the tropic of Capricorn.

Emporto.

EAU,INDIEk CAPE OF GOOD HOPE,

. .• . ,
Lord Stanley,•(336), Artburs, fm Bombay, with :.1668 bales 64 half
hales votton,.49'halea 2 half bales.safdower, 6es cardamoms, 182 hags
140 1141 f-bales ginger, 78 bags galls, 60 t sapau wood, 3 bxs tea, 2 bxs
presenrS:"Order—P Dk
Brielget; (4051- Croshie; fen Caletitta.,- with 912 bgs rice; 2591 bgs salt='
petrel 555 bgs sugar,.s2bls hides, .6 cs 'silk pee goods, s his -1 pret silt ,
1 bx ehints,•2B clata.shellae,•l3lo-bgl linseed, 200 Ida kite, 124 pa red.
w00d,,2 boxes sundries, 2000 buffalo bores, 2.52 bags: horn tips-,1 box
sweetmeats, 78 bls safflower, Order,-830 bgs rice, Golhorne R Doblis
Presents; C Humberston and cO-1 do, • Crary, Fletcher and en
—5 do, J bx silk, Ogilvy, Gillanders'anit bale-4 raw
silk,' Sands,: Turner and co-70 his hides, ,FeigasOn,•:llliller and co—
I. curiosities, A Wain wright-r-l•bx cigars, Vtr Stewart Dk

WEST INDIES AND MADEIRA:
SandWaal, • (435) BiOham, fin Demerata; with oa. hds 2 hf tcs su-
gar, hds 20 pus 74 brls rum, Si ndbach, Tinne and co-15 lids sugar,
T an&11 Murray-,P Dk •
Helen Jane, (206) M`Donald, fin Demerata, with-`262 lids 42 tcs ,25
hrls sugar, 96 pus 20 hds 19 brie rum, .J Gladstone.and co 70.hd4•su~
mr, l hd shrub, .1 hi arrowroot, 3 ps letlerwood, 3 bas conts iiku,
Order-10 pns 2 hds rum, T and II Murray-7G Dk