en alluded to. In this interstitial condition
its amount is usually very small--a fact already pointed out by Zirkel.

I have unfortunately had no opportunity of examining the volcanic sands
and ashes of Etna, but Zirkel's description of them seems to indicate
their close mineralogical relation to lavas erupted in this district,
with one exception, as pointed out by Rosenbusch,[24] namely, that he
makes no mention of the occurrence of olivine in these ejectamenta.

[24] "Mikroskopische Physiographie der Massigen Gesteine. Stuttgart,
1877; p. 547.

Reference to the Figures 1 and 2 will suffice to show how close a
relationship in mineral constitution exists between these two lavas,
separated in the dates of their eruption by an interval of over two
thousand years.

* * * * *

_New Maps of Etna._--After these pages had received their final revision
in type, I met with two new maps of Etna in the Paris Exhibition. The
literature of our subject will obviously be incomplete without some
notice of them, although this belongs properly to the first chapter
rather than to the last. The one is a map in relief constructed by
Captain Francesco Pistoja for the _Istituto Topografico Militare_ of
Florence. The vertical scale is 1/25,000 and the horizontal is 1/50,000.
The surface is coloured geologically: the lavas erupted during each
century being differently coloured, while the course of each stream is
traced. This map, although by no means free from errors, is a vast
improvement on the relief map of M. Elie de Beaumont. One defect, which
might be easily remedied, is due to the fact that the lavas of three
consecutive centuries are coloured so much alike, that it is almost
impossible to distinguish them. The minor cones are well shown, the Val
del Bove fairly well, and the map is altogether a valuable addition to
our knowledge of the mountain.

The other map is a _Carta Agronomica dell' Etna_, showing the surface
cultivation. Different colours denote different plants, pistachio nuts,
vines, olives, chestnuts, etc. It is beautifully drawn and coloured by
hand, and is the work of Signor L. Ardini, of Catania.

INDEX.

Abich, 22
Acesines, River, 81
Aci Reale, 72, 73
Acis, River, 73
Acque Grande, 73
Aderno, 65
Adranum, City of, 66
AEschylus, 4
Aetna, Town of, 64
Ajo, Fountain of, 85
Alcantara, Valley of, 69
Amphinomus, 80
Analcime