92 Proceedings of Learned Societies. 
ing addition to the list already published 
by Mr. Colebrooke. 
LINNEAN SOCIETY. 
May 4.—The reading of Mr. Morgan’s 
paper on the mammary organs of the kan- 
garoo was continued, containing further 
particulars of the dissection of these parts, 
as well as of the muscles attached to the 
[Juny, 
bones of the adult and impregnated animal. 
—May 24. This day was the anniversary 
of the Society ; and Lord Stanley was elect- 
ed president in the room of the late Sir J. 
E. Smith; and E. Foster, J. E. Bicheno, 
and R. Taylor, Esqrs., respectively re-elect- 
ed to the offices of treasurer, secretary, and 
under secretary. 
VARIETIES, 
SCIENTIFIC AND MISCELLANEOUS. 
Guinand’s Glass.—The materials used in 
the composition of glass are some saline sub- 
stance, and some sort of silicious earth. 
With respect to the latter, it is indeed said, 
that all white transparent stones which will 
not burn to lime are fit to make glass. 
Where proper stone cannot be had, sand is 
used; and it is now almost the only kind of 
substance employed in the British manufac- 
tures of glass. The other ingredient is an 
alkali, either soda or potash, which is always 
used at first in a state of carbonate. There 
are other fluxes used for different kinds of 
glass, and for various purposes: of the ox- 
ides of lead, litharge and minium are 
‘found to be of singular use: the first of 
these is a powerful flux, and imparts to 
glass the valuable qualities of greater den- 
sity, and of greater refractive power. A 
considerable quantity of this oxide is con- 
tained in the finer glasses, the flint-glass in 
particular, and that which is used for the 
table, for lustres, for artificial gems, and for 
most optical purposes. It is, however, well 
known that glass which contains much lead 
is extremely soft, very fusible, and liable to 
be corroded by very acrid liquors. There 
is, beside, much difficulty in so contriving 
the materials, that the glass shall be through- 
‘out of uniform density. Still this does not 
‘seem to present an insurmountable obstacle ; 
and, from some analyses that have been 
made of M. Guinand’s Swiss flint-glass, we 
should be induced to conclude that it is to 
the successful employment of this material 
that the superiority of his flint-glass has been 
owing. But a glass which is liable to cor- 
rosion by a powerful acid would likewise 
appear susceptible of oxidation—an unlucky 
‘process, which it is rumoured that a cele- 
brated object-glass constructed from some 
of his glass, is at present undergoing. 
Earthquakes in 1827.--The following 
list of earthquakes, which occurred in the 
course of last year in different parts of the 
world, has appeared in a foreign journal :— 
January 2. At Mortagne (Ome) and its 
environs: a violent shock, ofshort duration, 
accompanied with an intense noise. Chim- 
nies and household furniture were thrown 
down ; the commotion reached as far as 
Alencon ; the day was cloudy, the weather 
thick and stormy, which is unusual at that 
time of the year.—February 9. At seven 
o'clock in the, evening, “in the north-west 
-part of Wales, and the Isle of Anglesea. 
The shocks continued from forty seconds to 
a minute; they were sufliciently violent to 
overturn several pieces of furniture. A noise 
was heard like that of a heavy-laden cart 
going on the stones.—April 2. At Beverss, 
at twenty minutes past one in the morning, 
two strong consecutive shocks. The inha- 
bitants of Basse Engadine assert, that they 
counted twenty similar shocks during the 
winter.—May 29. At Vajaca, in Mexico, 
two slight shocks.—June 5. At Martinique, 
a slight shock.—June 12. At Tehenecan, 
in Mexico, at half-past one o’clock, a violent 
shock, with a frightful noise ; many build- 
ings damaged.—June 16. At Aquila, in 
the kingdom of Naples, a shock, at five 
o’clock in the morning.—June 2]. At Pa- 
lermo, at eleven in the morning, four strong 
shocks in the space of seven seconds: it 
Was an oscillatory motion from the west to 
the east.—August 14. At Palermo, at 2 
p- m., several shocks ; they continued about 
eighteen minutes, with very short intervals ; 
the motion was always oscillatory. — Sep- 
tember 18. At Lisbon, a slight shock.— 
October 10. At Zurich, and all the shores 
of the lake, at twelve minutes before 3 
p-m., a strong shock.—October 15. At 
Jassy, at eight in the evening, two violent 
shocks, directed from north to south, and 
accompanied by a subterraneous noise : 
two or three days after, the heat was very 
great.—October 30. At Corsica, in the can- 
tons of Taravo, Tagliano, and Sartene, two 
shocks, at twenty minutes past 5 a,m.— 
-November 30. At Pointe-a-Petre, Guada- 
loupe, at three in the evening, a violent 
earthquake. At Mariegalante it was pre- 
ceded by a strong and sudden storm. 
New Cannon.—We mentioned in this 
journal, several months since, that a Colonel 
Paixhans, of the French artillery, had been 
endeavouring to introduce into the marine 
of his nation a comparatively light cannon, 
of very large calibre, for the purpose of dis- 
charging point-blank explosive shells at sea. 
Whether they will be employed on board 
vessels engaged in civilized warfare, remains 
to be seen. But, for some short time since, 
a new sort of howitzer, in every particular 
appearing to correspond with the gun de- 
signed by Colonel Paixhans, has been in- 
troduced into the British service; and one 
of them is now to be found attached to each 
of our brigades of guns, capable of dis- 
caging a solid shot, or a hollow projec~ 
tile. 
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