joined the main line at
Mladenovatz. Thus the Austrians would have a convenient side door
open into the heart of Serbia which was, of course, their main
objective. To this Belgrade was merely incidental. With this line
of transport and communication in Austrian hands, Belgrade would
fall of itself.

From Losnitza, where the main column of Austrians crossed the Drina
to Valievo, runs the River Jadar, along a level valley, which narrows
as it nears Valievo. On the left-hand side of the Jadar Valley rise
the southern slopes of the Tzer Mountains, covered with cornfields,
prune orchards, with here and there a stretch of thick timber.
Continuing southward, slightly to the eastward, up the Jadar Valley
another range rises, slightly smaller than the Tzer Mountains,
forming a smaller valley which branches off eastward. Along this
runs the River Leshnitza, parallel with the Jadar until it makes
an independent junction with the Drina. Still farther up the valley
the foothills of the Iverak ridges are lost in a series of fairly
important summits which closely flank the Jadar River.

To the south of the Jadar River the valley stretches into a rolling
plain, which rises abruptly into the giant Guchevo Mountains. It is
this range, converging with the Tzer and Iverak Mountains toward
Valievo, and forming the plain of the Jadar Valley, which was presently
to become the center of the first great battle between the Serbians
and Austrians.

A military movement against Valievo, therefore, demanded complete
possession of these two ridges, which overlooked the line of march.
This the Austrians knew well enough, even before the first of their
troops had crossed the Drina. As is well known, the best maps, not
only of Serbia but of all the Balkan countries, have been made by
Austrian engineers. There was probably not a spur, not a fissure,
certainly not a trail, of these mountains that had not been carefully
surveyed and measured by engineers of the Austrian staff.

The Austrians knew the country they were invading quite as well
as did the native Serbians. All through it may be said that it was
not through want of accurate knowledge that the Austrians finally
met disaster. Rather was it because they misjudged the relative
values of their facts. And one of their first mistakes was in
overestimating the effects of the two Balkan Wars on the efficiency of
the Serbian army. First of all, as was obvious from the leisureliness
with which they