Foreign Laterature and Science. 385 
to 9 inches long destined to receive the substance to be acted 
upon by the solvent. It isclosedat bottom by a cork a, a, (see 
pl. 10, fig. 5,) wee which passes the small tube b, b, open 
at each end, except that it is covered with muslin at x to 
prevent the pulverised substance from passing into it. One 
half of the tube A is filled with the vegetable powder, and 
the other half with the fluid. The small tube is adapted by 
means of a cork to the small globe B, freed from air by a 
few drops of alcohol, which by the application of heat ex- 
pands into vapour and expels the air. The small tube is 
then tightly pressed into its neck, and the apparatus is set 
in acool place. As the alcoholic vapour contracts and then 
forms a vacuum, the pressure of the air forces the liquor 
through the pulverised mass and thence into the globe In 
a few minutes a portion of extract is thus obtained, which 
being withdrawn, the vacuuin may be renewed by alcohol, 
and the process thus continued at pleasure. 
14. 4 Steam Boat either has been, or is about to be con- 
structed on the Lake of Geneva in Switzerland by our coun- 
_tryman Edward Church ; who was the first to bring steam 
navigation into succe .sefal operation in France by the estab- 
lishment of a steam boat on the Garonne. The Swiss boat, 
(the first, it is believed, yet attempted in that romantic coun- 
try) will ply between Geneva and Lausanne, stopping a 
few minutes at Copet, Niou, Rolle and Morges, and per- 
haps extending her voyage —— to Vevey and the 
Chateau de Chillon. A m picturesque and delightful 
navigation can scarcely be Sblecirad. qi 
V esuvius.—By a letter from Naples dated Novem- 
bet si, 1822, published in the Bib. Univ. of Geneva for the 
same month, it appears that the eruption of Vesuvius which 
took place on the 22d of October was as terrific as any that 
has occurred since A. D. 79 described by Pliny. Day was 
turned into night by the clouds of ashes and other volcanic 
matter, which at a distance from the mountain, fell to the 
depth of 5 and 6 feet. The writer collected several pounds 
of the ashes from his Balcony in Naples. It was at first of 
a reddish brown, and then more white, and appeared to him 
like pulverised pummice stone. He states that it had been 
analysed by M. Pépé who — in it sulphate of potash, 
Vol. VIL—No. 2. 
