The Liverpool Standard and General Commercial Advertiser.
Liverpool, Merseyside, England, 1836-10-11 00:00:00

than one-thousandth part of the light impinging ❑pon them.
We may, in some cases, increase the reflecting power, by ad-
ding to transparent bodies substances which have greater
powers of reflection. Thus, if we coat the inside of a glass
cylinder with paint, with the exception of a small portion,
against which, the light of a lamp may be directed, we shall
find, upon filling it with water, that the water will not be visi-
ble, but if a.few drops of milk be added to the water, light
will. be reflected from it. Mr. Addams here exhibited a
table computed by Mr. Potter, of Manchester, showing the
amount of reflection in plate-glass mirrors of different angles
of incidence, by which it appered that, as the angle increases,
the greater number of rays are reflected, but under the most
favourable circumstances, one•half of the rays will be lost.—
This varies much in metal refl •ctors ; thus, inlspecula metal,
used in the construction of observatory astronomical instru-
ments, the greater the angle of incidence, the less will be the
quantity of light reflected. The following are a few of the
most remarkable of the reflecting properties of different sub-
stances :
Water, at the greatest possible angle of incidence, will re-
turn three quarters, and Glass two-thirds of the rays. Water,
at the perpendicular incidence, will return only one-fifty-fifth ;
whilst Glass will return one-fortieth ; and Mercury two-thirds
of the rays. We thus gain more from metallic reflectors, at
the rectangular incidence, than from other substances.
If a light be reflected against a wall, it will be found that upon
moving the reflector through a quarter of a circle, the image
will have traverser) through double the distance. Sextants,
quadrants, &c., are constructed on this principle, so that the
whole of the heavens can be readily seen. If the surface of a
reflector be convex or concave, the light will not be reflected
as from a plane, but the law governing the circumstance will
be the same. A concave reflector will bring all the rays into
a speck of light at a given distance ; hut a convex reflector will
spread them out in every direction. The concave reflector pro-
duces the same image which it received, which can be magni-
fied at pleasure. It is obvious that any lines drawn from the
centre of concavity to the curve must be perpendicular to that
part of the curve, because the radius of a circle is always per •
pendicelar to the tangent of that point of the curve which it in-
tersects. All rays occurring in the direction of the axis of the
mirror, are returned in the same direction. The focus where
the rays will assemble, is always equal to one half of the radius
of concavity of the mirror, with a little variation, hereafter to
be noticed, according to the colour of the ray.
When light is reflected, it belongs to that division of the
science called Catoptrics, but when it is bent or refracted by
passing through a body, it belongs to the division called Diop-
trics. If a portion of light be passed from one light into ano-
ther, where the density and elasticity of the other is much dif-
ferent, then the light will take a different direction, unless it
fall at right angles. We will suppose that the light is passing
through the 'wther of the air, and that it meets w►th a quantity
of water. When a ray of light meets the water, a small por-
tion of it is reflected ; the remainder will enter the water. The
instant it reaches the water, it is bent at the point of contact of
the two media. This bend, like every operation of nature, is
invariably certain and uniform. We find that where air and
water are concerned, that, if the ray above he of such an angle,
that the sign of that angle shell measure four feet, or inches,
and that the sign of the angle of refraction shall measure three
feet or incites, that is to say, the upper and lower angles are as
four are to three.
A ray of light may be reflected from the bottom of water in-
to the air. Suppose a polished plate of metal be placed at the
bottom of a cistern, and the light of the sun falls upon it, the
ray would be bent and carried out of the water in the same
manner as in going in. The sane will happen to all transparent
bodies that have higher refractive powers than the atmosphere,
but in varying proportions. Tables are frequently given show-
ing the indices of refraction for various substances. These in-
dices are the quotients of the sign of incidence, divided by the
sign of refraction. It is usual to consider the tingle of refrac-
tion as one, so that the angle of incidence will he one and a de-
cimal, which is called the index of refraction. Mr Addams
illustrated the -retraction of water by throwing a ray of light
into a glass cistern containing water. Owing to this refraction
of water tire position of substances in it is apt to be mistaken
and inexperienced individuals, in attempting to spear a salmon,
almost invariably miss the fish by striking in the apparent
rather than the real direction, besides which the fish appears
much higher in the water than it really is. Mr. Addams illus-
trated this in a very curious and satisfactory manner. He
placed a piece of lead, having a transparent point struck upon
it, at the bottom of a tin trough, SO that it could not be seen
by the audience whilst sitting down. When water was poured
upon the lead sn as to cover the transparent point, it could be
be seen by the audience without any alteration in their position.
Another very demonstrative illustration of this refraction of
light in water was presented by Mr. Addams, with which he
concluded his lecture. If in a graduated disc of metal two
tithes be placed, and tin angle be made with them equal to the
angle of refraction, a person looking through one tube will be
able, if the experitnent be properly conducted, to see through
both tubes any article at the bottom of the water.
We were glad to observe a number of scientific gentlemen
present at this lecture—it proves that genuine talent is duly
estimated in the town.

CLERICAL LIBRARIES.

TO THE EDITOR OF THE LIVERPOOL ST,INDIRD.

Sia,—lam glad to observe that the subject of clerical libra.

ries is exciting some notice.
The disadvantages which the clergy generally, and students
in particular, labour under is scarcely credible from the want of
access to our literary treasures in divinity. They are, as it
were, sealed books. In church history, for example, the re-
sources are so numerous that it would require a small fortune
for a private individual to make an available collection. Mau),
of our theological students would be found very deficient in this
department were they, like all candidates for holy orders in the
Scottish Church, examined touching church history. Few per-
haps even of our elder ministers could write .such a work of
extensive research as A. S. Patterson's "History of the Church
from the Creation of the World to the beginning of the 19th
Century ;" yet its pious and learned author died in the prime
of life, being only twenty-five years of age.
As supplying the necessary weapons to fight the adversaries
of the church and religion, surely ready access to a valuable
theological library would be signally useful The Romish
clergy owe much of their authority to their deep learning, and
are not, therefore, to be met by mere simple good intentions on
. .

.re part of their opponents. Something besides is wanting;
the same weapons, the same learning; the fullest acquaintance
with arguments that have already been advanced, and all the
wisdom accumulated in the luminous pages of the fathers and
all celebrated theologians. To what extent are we familiar with
Calvin, Erasmus, Owen, Hall, the fathers of the church, and a
host of others too numerous to name?
I was reading the other day an extract from the visitation
sermon, preached at Ampthill, Herts, in September, 1827, by
the Rev. S. Piggott, Rector of Dunstable; as follows:
" In these eventful times, we are particularly called upon to
guard ourselves on three quarters, en which the chit rcli of
Christ is besieged and attacked by formidable and deadly foes.
Sentimentalism and infidelity have long attacked one flank of
the host of God : Popery has still longer harrassed the other ;
and now it fair but fatal liberality of sentiment is giving aid to
both, by lifting up its weapons of scorn in defiance of the living
God. The bulk of the refined part of the community are on.
wittingly becoming Socinians in principle, and libertines in
practice. Scepticism is undermining all Christian faith in
their minds, and ail religious principle in their actions, till
they become indifferent to all religious opinions, and over-
reach the simple by the most fraudulent confederacies. Popery
veils the truth and renders it contemptible, and thus prepares
men to embrace Unitarianism or infidelity. We need protest
against the Church of Rome as a system of idolatry. The in-
difference which our legislature has shown to the question of
Popish idolatry. bodes the kingdom no good. The idolatry of
the Church of Route is a mere question of party among us, in-
stead of an abomination which we should fear to support.
Popery is the poisonous Upas tree which scatters death. No-
thing but the grossest ignorance of its noxious influence could
determine our miscalculating politicians to suffer it to be
planted and flourish on British ground."
How are the false notions of the people to be combatted, and
the false positions of our enemies exploded, except we are pie-
pared, not only with the wisdom which is front above, but like-
wise with all intellectual stores Which have accumulated for
.ages to the honour of religion. Are a few modern treatises all
that is required ? Does theological knowledge lie in a nut
shell? Is it wiser to trust to natural talents, and original think-
ing than to be troubled with learning how far our predecessors
have gone, and wherein their strength lies ? Is it time enough
to buckle on our armour, to prepare for the fight, to sound the
alarm—when our enemies are up—in sight—hastening to our
destruction! The Christian soldier should ever be guarded,
whether in season or out of season.
It is sincerely to be hoped, that something will soon be done
to effect the establishing of a good library of divinity.
I am, yours, &c.
A LOVER OF LEARNING.

THE WHIGS AND RADICALS AT HALIFAX.-,-(From a cor-
respondent.)—The whigs of Halifax, as is well known, had 'a
feast on Friday last, and after dinner a great portion of the
company drank to such excess that they got beastly intoxicat-
ed; and, as is usual in such cases, uproar, riot, and disfigured
physioguomies followed; tables, chairs, decanters, and glasses
were capsized, and the guests themselves lay sprawling upon
the floor, in indescribable confusion. The radicals had their
gathering on Monday, anti it is but justice to say that they cou-
ducted their business in a much snore becoming manner than
the whigs. No ladies were admitted at 2s. 6d. a-head—no gen-
tleinen drank brandy until they lost their equilibrajtooilitT:ior
tables were upset with all the et ceteras which
surface—no cracked heads, tattered .garmentssr arnklde:ttorted
countenances; and, lastly, no disgusting and swine 1
etthinagt too
exhi-
bition of wallowing in the filthy muckiness oftheir own crea-
ation.—Standard.
THE Doststow FLITCH OF BACON.---BArettyt
the Dunmow Agricultural Society, Mr. t
flitch, but that the
shheelratsearnide,
formally and properly made to claim)
his regret he had heard that day thtahaat plication had been
He did not know why
demand had been resisted. (Cheers.
oyous husband, the wife
Walden S .. t l ocie y lad come
occasions in Dunmow, the Saffron
that objection was made, but when there were no such joyous
and be joined with '
whviclhayweer
the
ainndto c h
itakeld,
couldth e place,cama aa
sn d
candidates,t lie rte th.e .i _ .
Walden and Dunmow Some in harmony and concord.
(Cheers.) gaveth e
Esterrise
Herald short
a a follows
u had been allud d Mr.
efindaid , roesptohret efild'iht inflitch
e to, he begged to
d of as
offer a flitch to be dispose the committee of Dunmow
might think fit. (Loud cheers and laughter.) Mr. Brewsher
hoped they would allow him to propose that the pig should be
sh
of baco
fed by a member of the society, and the flitch cured at Dunmow.
(Cheers.) Mr. Fuller said he should be glad to receive pro-
posals froth any gentleman in Dunmow to provide a flitch, fat-
tened by a member of the society, to 'be produced about that
time twelve months. Mr. Wade said, as Mr. Player had given
them a flitch, lie (Mr. W.) promised there should be no gam-
'non in giving it away. (Cheers and laughter.) He was afraid
they would not be able to produce a loving couple in Little
Dunmow to claim it, but perhaps they should from some other
place."
Letters front Bombay state, that an Agricultural Association
had been formed in that Presidency, to encourage the growth of
Sugar, the cultivation of the Mulberry, and growth of Wool;
the first report is of a very encouraging character.
A certain venerable gentleman, an artist, known to fame, and
honoured by the addition of B.A. to his highly respectable name,
was, a day or two since, walking in the neighbourhood of Soho-
Nuare, and became mach surprised at seeing a wretched daub
exhibited at a shop window for sale, with a placard fixed upon it,
saying, "This fine original picture of Bacchus and Ariadne,
by _ (the artist above referred to,) only twenty.
.guineas."
This was toe bad—the sight of his name to a production which
would almost have shamed a painter of teaboards was too much
:
for the philosophy of Mr.—. He went into the shop, and
assured by the proprietor that the picture was "ant
sourilirnailn.;
"Then, Sir," said the old gentleman, h to my pen"
name to be disgraced by such a thing being
ash
ou li the can-
! cll." With these words he dashed his stick t r it.
effect as
dose with such
vass of the painting, and repeated the
stormed, the artisttook
nearly to destroy it. The picture-dealerou
" I willrinood tte
leaving his card on the mans counte . 11,
it quietly, and his leave, first going
rh...._tgehaintghepacpeer,e.mony of