regarded by the Austrians as their first
line of defense. For almost its entire length, as far south as
Salcaro, about four miles north of Gorizia, the Isonzo River runs
through a deep gorge and is easily defended. From Salcaro to the sea
it issues from the gorge into a more level country--the plateaus of
Gorizia and of Carso--although even the southern part of the line is
dominated by a series of elevations in supporting distance of each
other. Until the line of the Isonzo was forced, Trieste and the entire
Istrian Peninsula might be regarded as safe.

Although the line of the Isonzo was, as has been shown, the only
feasible line on which Italy could advance, no serious offensive could
be attempted until the outlets from the Trentino were thoroughly and
effectively stopped up. For Italy to have advanced in the Carso, with
her rear open to attack by the Austrians coming through the Tyrolean
passes, would have been foolhardy. Italy's first step, therefore, was
to start a simultaneous forward movement through every pass from
Stelvio on the west to the pass near Pontebba on the north. These
movements naturally were of an offensive nature, although they were
really for a defensive purpose. No attempt was made to advance any
distance through the western passes. The Italians were content to take
the fortifications guarding the entrance and to seize heights
commanding the approaches.

On the south and east of the Trentino, however, the operations took on
a more extended and, for the Austrians, a more serious aspect. On the
south the principal efforts were directed against Riva and Rovereto.
The operations against Riva, which is situated at the head of Lake
Garda, were directed along the valley of the Ledro and thence along
the Tonale River, a small stream connecting Lake Ledro and Lake Garda.
At the same time the Italians pushed with energy down the Val Sugana,
which leads directly to Trent. The advance was pushed to a point where
there was no possibility of the Austrians coming through, and there
the Italian forces rested.

Well up, toward the north, in the Dolomites there followed
considerable fighting, in the Cordevole Valley particularly, for the
Col di Lona, the loftiest of the mountain tops in that region. The
Cordevole unites with the Val Forsa some twenty miles east of the
Adige Valley, the Val Forsa connecting with the Adige at the town of
Lavio, six miles north of Trent. To cut in behind the Austrians south
of Tr