1824.] 
tense frost, and the usual return of the 
water-birds a thaw; that the examina- 
tions of the latter prove them to have 
taken long flights before their return, and 
sets the fact of temporary migration be- 
yond the reach of doubt. The paper con- 
cludes with some additional particulars 
respecting the different sizes of the. gene- 
rative organs of migratory birds, as they 
appear at different seasons of the year. 
A mass of meteoric iron, maleable and 
very ductile, and containing nickel, weigh- 
ing about 1,655lbs., has been found by 
Messrs. Rivero and Boussingault, on the 
hill of Tocavita, in the mountains of Santa 
Rosa, between Timja and the plains of 
Bogota, in South America. In the same 
vicinity, several smaller masses of similar 
iron were found on the surface ; all of them, 
probably, fragments thrown off at the same 
instant from one of the myriads of satel- 
litule of our planet, which (according to 
Mr. Farey), from the period of their crea- 
tion, have continued to revolve around it 
in elliptical orbits—the perigeic parts of 
which orbits pass through a portion of our 
atmosphere, the resistance and chemical 
action of which last occasions the tempo- 
rary luminocity of these bodies—also, the 
explosive exfoliation of their superficial 
parts,—the continual lessening of their or- 
bits, as an elliptical spiral, after each of 
such perigeic visits, and a consequent 
deeper and deeper penetration within our 
atmosphere ; until, probably, the remaining 
masses of many of these bodies have fallen 
to the earth, or into the seas which cover 
so large a portion of its surface. At Ras- 
gata, in a different part or Mexico, a mass 
weighing 169lbs., and another 90lbs., of 
similar nickelated iron, have been found, by 
the same observers. 
Starjelly, star-shot, ( Tremella Nostoe. )-— 
These singular gelatinous small masses, 
which are found occasionally on marshy or 
fen grounds, are asserted by Mr. W. Fo- 
thergill to be mostly the decomposed bodies 
of frogs or toads, which have died during 
moist and wet weather. Those which die 
during hot and dry weather do not undergo 
this change ; but their bodies shrink up into 
a leathery substance.— Phil. Mag. No. 316. 
Ice, naturally formed during summer in 
some caves, is dissolved during the ensuing 
winter.—This remarkable fact has lately 
been verified, as to the ice-cave of Mon- 
targuis in Switzerland. M. Gampart vi- 
sited this cave in the summer of 1823, and 
found much ice accumulated and rapidly 
increasing ; yet two persons, who, in the 
following autumn and winter, three times 
visited the same caye (with much diffi- 
culty), found the ice rapidly melting there- 
in, and at length it had entirely disappeared, 
Professor Picket has offered, as an expla- 
nation of this phenomenon, the currents of 
air which descend through fissures in the 
roof of the cave, greatly cooled by evapo- 
ration in summer ; and the contrary cur- 
Spirit of Philesophical Discovery. 
239 
rents of air which during winter ascend.— 
Bib. Univ., vol. xxy, p. 243. 
Very accurate casts of the leaves of plants 
may be prepared by a very simple process, 
which Mr. W. Deeble has described to the 
Society of Arts. A quantity of fine-grained 
sand, in rather a moist state, must be pro- 
vided, on the surface of which a leaf se- 
lected for casting from should be laid, in 
the most natural position which the taste 
of the artist can effect, by banking up the 
sand beneath its more elevated parts, by 
the lateral pressure of the blade of a knife; 
when thus the leaf has been supported in 
every part, its surface should, by means of 
a broad camel-hair pencil, be covered over 
by a thin coating of wax and Burgundy 
pitch, rendered fluid by heat; the leaf be- 
ing now removed from the sand and dipped 
in cold water, the wax becomes hard, and 
at the same time sufficiently tough to allow 
of the leaf being ripped off from the wax 
mould,without altering the form of the latter. 
The wax mould is now placed on the sand, 
and banked up in every part, as the leaf at 
first was ; and then an edge or border being 
raised of sand around the leaf, at a suffi- 
cient distance, very thin plaister of Paris is 
then poured over the leaf, and a camel-hair 
pencil is used\ to brush the fluid plaister 
into every hollow on the surface, and ex- 
clude air-bubbles. As soon as the plaister 
is set, it will be found, on taking it up 
from the sand, that the heat generated 
during the setting of the plaister, will have 
softened the wax, and that the same may 
be dexterously rolled up from the impression 
thereof on the plaister: and thus the most 
beautiful and perfect moulds may be ob- 
tained for making any number of plaister 
casts in relievo, of the leaf which has been 
selected. 
The possibility of changing the residences 
of certain fishes from salt-water to fresh, has 
been shewn by numerous facts and very 
able reasonings, in a long paper by Dr. 
MacCulloch, in the Journal of Science, 
No. 34; as also the probability, that effect- 
ing this change might greatly enhance the 
value of the inland and fresh-water lakes 
and waters, which so much abound in Bri- 
tain: in conclusion the Doctor remarks on 
the insufficiency of that very fashionable 
geological theory, of French origin, which, 
from the conjectured fresh-water, or the 
imagined marine habits of the mollusca 
formerly, whose shells are now found im- 
bedded in the strata, pretends to infer the 
existence formerly of fresh-water lakes, or 
of the sea, in random succession upon the 
same spots, during the progressive forma- 
tion of the strata: idle whims, which have 
much retarded the march of useful geo- 
logical research, and tended also to unsettle 
and empirize conchology. 
An easily procured substitute for a chaly- 
beate’ spring has been discovered by Dr. 
Hare, in America.—If several pieces of 
silver coins, and several pieces of thin oe 
plate 
