sufficient to
guide the footsteps of the inquirer. The basin of the Lake of Laach is
nearly circular and crateriform; it is a mile and a half long, and about
a mile and a quarter in breadth. Its average depth is two hundred feet,
but it is full of holes, the measure of which is very uncertain. Its
water is blueish, very cold, and of a nasty brackish taste. It has been
examined by several geologists, British and foreign, among whom is the
famous Humboldt, and there is no doubt that this great reservoir is the
crater of an extinct volcano. The fragments and minerals thrown up on
the banks are analogous to those found in other volcanic countries; and
on one side (that towards Nieder-mennig) is a regular rock of continued
lava, which is supposed to have flowed from the crater during the last
eruption. Mr. Scrope, whose opinion is entitled to great weight, thinks
it not improbable that this may have been the eruption recorded by
Tacitus, (13 lib. Annal.,) as having ravaged the country of the
Initones, near Cologne, in the reign of Nero. I should not forget to
mention that there is a cavern within the basin of the lake, the air of
which is so stifling and noxious, that animals die if forced to remain
in it, and lights are extinguished by the gas--phenomena precisely
similar to those of the well-known Grotto del Cane, near Naples.

While I am on the subject of volcanic phenomena, I may as well add a
word on the origin of the trass or tufa, which is so thickly spread over
this country. It is similar to that found near Naples, at Mont d'Or,
Carbal, and other parts of Italy; and, indeed, all the products of the
latter district are pretty nearly the same as these, allowing for the
difference of a slate surface in the one case, and a sandy and alluvial
soil in the other. The idea of the trass having any connexion with a
deluge, is, I believe, now exploded; and geologists have agreed that it
is the actual substance ejected by the volcano, subsided into a firm
paste. The rain has always been observed to fall heavily after
eruptions, and the water running down the sides of the hills, has formed
this crust, which makes the bottom and sides of the Laach. The same
causes are in action now; and if ever the lake should rise so high as to
burst its banks, it would overflow the whole country, and carry terrible
destruction with it. Such an event was actually foreseen by the
sagacious monks who formerly inhabited the abbey, for they cut a can