isseminated through the lavas in the
form of small crystalline grains, sometimes of some magnitude. Specific
gravity 3.334. A specimen from Etna gave the following results on
analysis:--

Silica 41.01
Protoxide of Iron 10.06
Magnesia 47.27
Alumina .64
Oxide of Nickel .20
Water 1.04
------
100.22

The titaniferous iron of Etna is found disseminated through the mass of
the lavas, and is plainly distinguished when a thin section is examined
under the microscope. It is sometimes met with in masses. A specimen
from Etna, analysed by Von Waltershausen, was found to contain:--

Titanic Acid 11.14
Sesquioxide of Iron 58.86
Protoxide of Iron 30.00
------
100.00

The basalts of the Isole de'Ciclopi enclose beautiful transparent
crystals of Analcime, the _zeolite dure_ of Dolomieu. The word is
derived from ~analkis~ weak, in allusion to the weak electric
power which the mineral acquires when heated or rubbed. Dana prefers the
term _analcite_. Specimens from the Cyclops Islands have been analysed
by Von Waltershausen and Rammelsberg, with the following results:--

I. II. III.

Silica 53.72 55.22 54.34
Alumina 24.03 23.14 23.61
Lime 1.23 .25 .21
Soda (Na{2}O) 7.92 12.19 12.95
Potash (K{2}O) 4.46 1.52 .66
Water 8.50 7.68 8.11
Magnesia .05 -- --
Sesquioxide of Iron -- -- .12
----- ------ ------
99.91 100.00 100.00

The minerals of Etna are not nearly as numerous as those of Vesuvius. It
has been remarked that no area of equal size on the face of the globe
furnishes so many different species of minerals as Vesuvius and its
immediate neighbourhood. Out of the 380 species of simple minerals
enumerated by Hauy, no less than 82 had been found on and around
Vesuvius, as long ago as 1828, and many have been since found.

Of other common products of Etna, there are sulphur in various forms,
sulphurous acid gas, ammonia salts, hydrochloric acid gas, and steam. A
curious white