The Sun.
London, England, 1832-12-07 00:00:00

ROYAL SOCIETY.

From a variety of papers read at the evening
meetings of the Royal Society in • Somerset-
house, we have selected the following interest-
ing memoranda for the perusal of our scientific
readers, of whom there are many to be found
amongst the middling and working classes :
On a simple electro-chymical method of ascer-
taining the presence of different metals, applied
to detect minute quantities of metallic poisons,
by Edmund Davy, Esq., the brother of Sir
Humphrey. The voltaic arrangement employed
by the author consisted' merely of small slips of
different metals, generally zinc and platina, placed
in contact and forming a galvanic circuit, with the
interposed fluid suspected to contain the poisonous
metal, in which case the metal held in solution
is deposited in the form of crystals on the
negative surface. The zinc was usually em-
ployed in the form of foil ; the platina was, in
some cases, a small crucible or a spatula, but
more frequently platina foil was used. It is ge-
nerally necessary to mix a few drops of acid with
the metallic compounds that are subjected to
this test, and that are placed in contact with the
platina. On applying the zinc foil the plating
will soon become coated with the reduced metal.
By this means the author was enabled to detect
the presence of arsenic by the exhibition of its
characteristic properties, when only the 500dth
part of a grain of that metal was deposited on
the platina ; and in some instances could appre-
ciate the 2,500dth part of a grain by the appli-
cation of appropriate tests. The author next
ascertained that the electro-chymical method is
competent to the detection of very minute
quantities of the different metals when their com-
pounds are mixed with various vegetable or
animal substances.

On the caves and fissures in the western dis-
trict of the Mendip-hills, Somersetshire, by the
Rev. D. Williams. The first cavern described
is situated at Uphill, at the western extremity
of the Mendip-hills. Its present entrance is
about midway in a mural face of transition lime-
stone, about a hundred feet high. The fissure
leading into it is nearly vertical, and was dis-
covered by some quarry-men casually intersect-
ing it. Some bones and teeth being found
there, Mr. Williams was induced to pursue the
exploration of the fissure, in the course of which
he discovered bones of the rhinoceros, hyaena,
bear, ox, horse, hog, fox, polecat, rat and
mouse, and also of birds. The bones of the
animals of the larger species were so gnawed and
splintered, and evidently of such ancient frac-
ture, that no doubt could exist of the cave
having been a hyxna's den, similar to Kirkdale
and Kent's Hole. After working six days, he
came to a cavern ten or twelve feet high, extend-
ing about forty feet from north to south, and
varying from eight to twenty feet from east to
west, the floor of which was covered with bones
*of sheep; and in digging into the mud and
-sand, of which it consisted, the bones of sheep,
birds, cuttlefish, and foxes, were discovered.
Some fine stalactites depended from the roof,
and partial spots of stalagmite appeared on the
floor. In a fissure that branched from the
mouth of the main entrance there were found
among the sand a piece of black Roman pot-
tery, and two coins, one of Didius Julianus,
and the other of Julia Marnmwa. Mr.
Williams considers that there exist evidences of

the operation of water at three distinct periods
of time ; the first indicated by the bones of the
hyxna, and the other gnawed bones being firmly
embedded in the diluvial detritus ; the second,
when sand was deposited by the sea in the
second fissure, that washed in through the ver-

tical chimney, and that inundated —the whole
valley up to Glastonbury ; the third, irruption of
the sea occurring within these 1,500 years, and
choking up the adit from the level by which the
sheep and foxes had entered. The chambers
the author reached in the Hutton caverns, are
probably the western extremity of a very exten-
sive range of caverns occurring in a region bearing
marks of great disturbance, abounding in chasms
and fissures, and containing a great number of
bones. No trace of the bones of the ox were
discovered here, although in a cave about a mile
distant they abound ; while, on the other hand,
no vestige of the horse is met with ! Among
the remarkable specimens found in the Hutton
caverns, were the milk-teeth and other remains
of a calf elephant, about two years old, and
those of a young tiger just shedding its milk-teeth;
and also the molares of a young horse that were
casting their coronary surfaces; the remains of
two hyrenas, of the extinct species, and two or
three balls of nlbuin greecum (the white solid
excrement of dogs). The caves lying about a mile
to the east of these are the property of the present
Bishop of Bath and Wells, and contain remains
of the bear, wolf; fox, deer, and ox. Of the
bear there at least two species, one of which ap-
pears to be the ursus spekeus of Blumenbach,
and must have been an animal of immense size
and strength. These remains were in general
not associated according to the animals they
th thus, belonged
the
hteoa, d buto fa
h ear indiscriminatelyla yby
the
femuro f
an
ofix
e,
naen the jaw
ed
it is
inferred
or
rf a e d wolf
that byth
et
shee
bones,antler of a de
after
ac-
cumulating for ages, were carried in by a tumul-
tuous rush of waters, and mingled together be-
fore their final deposition. In two caves, simi-
lar in appearance, and about six miles distant, no
antediluvian remains of animals have been found.
Several human skeletons and flint knives were
discovered by Mr. Williams, from which it has
been inferred that it had formerly been used as
a burying-ground.
On a proposed plan for supplying filtered
water to the Metropolis and its suburbs ; by L.
W. Wright, Civil Engineer. The author, after
giving extracts from the report of the Commis-
sioners appointed by the late King to inquire
into the supply of water to the Metropolis, in
support of the practicability of affording a supply
of filtered water from the Thames, adequate to
the demand, and within reasonable limits in
point of expense, proposes his plan of forming
a filter under the bed of the river for each
Company. He states that the deposit of
mud, on each side of the Thames, does not
reach below the low water-mark, and that the
bed of the river throughout is generally a clean
and strong though porous gravel. The mud,
therefore, will puddle in, and close the pores of
the bed of gravel on which it lies above low
water mark, so that the filtration into the neigh-
bouring wells„ the waters of which are remark-
ably pure, must take place below low water-
mark. He therefore proposes to construct a
filtering chamber below the bed of the river,
from which chamber a main pipe or tunnel must
be made for conducting the filtered water into
a well on the river side, whence it is to be drawn
up by steam power, and distributed to the houses
to he supplied by the mains and branches at pre-
sent existing.
On the variable intensity of terrestrial magnet-
ism, and the influence of the aurora-borealis

upon it, by Mr. Fox. The author is led to
conclude that the aurora-borealis is an electrical
phenomenon, and that it usually moves during
the night, nearly from north to south, and in
an opposite direction during the day ; that it is
of the nature of positive electricity ; and that
its elevation above the earth is much greater
than a thousand, and perhaps thousands of miles.

An account of operations carried on for ascer-
taining the difference of level between the river
Thames at London Bridge and the sea, and also
for determining the height above the level of the
sea of intermediate points passed over between
Sheerness and London Bridge ; by J. A. Lloyd,
Esq. The author of this paper received di-
rections from the Lords Commissioners of the
Admiralty in February, 1830, to survey the river
Thames, for the objects above specified. From
a series of observations made at Sheerness iv
the years 1827, 1828, and 1829, it was found
that the mean high-water spring tides was 26,355
feet; low water spring tides 8.74 ; mean, 17.649.
The mean high-water neap tides, 22.656 ; low
water, 11.336 ; mean, 16-993. The mean of
the whole period being 17-27. From the re-
sults of twenty-six years' observations on the
tides at the London Docks, it appears that the
height of mean high watermark there, above
that at Sheerness, is 2.24 feet ; and the height
of spring tide high-water mark 2.03 ; and of
neap tides 2-35. The Trinity mark on the
western side of where the old London Bridge
stood is 2.16 below the north standard mark at
Sheerness, and 1.9 foot above the mean spring
tide high-water mark at Sheerness. In the
course of his observations the author found rea-
son to believe that the tremulous appearance
of the air, which has been termed mirage, is
caused not so much by evaporation as by the
direct effect of the solar rays ; for he remarked,
that when there was a succession of clouds
passing over the sun, the tremor was very great
at those times when the sun shone ; but the mo-
ment the sun was obscured over the whole space
between the instrument and the object viewed,
the air was perfectly tranquil.