April 24, 1915. 
LAND AND .WATER. 
THE PARTICULAR POINT OF THE LATERAL 
VALLEYS. 
A mountain range nearly always has a par- 
ticular character which renders the problem of 
offence and defence within its limits different from 
that of any other obstacle, and this character must 
be explained diagrammatically. 
From the crest of a range of mountains X — Y 
(as shown on plan II.) there descend to the 
plain upon either side a system of valleys 
which usually run more or less perpendicular 
to the crest. Thus you w^ill have on one 
side of X — Y the streams 1, 2, 3, 4, and on the 
other side the streams a, b, c, d. These streams will 
commonly run through deep gorges, and will be 
separated by difficult secondary ranges (repre- 
sented by the dotted lines), across which it is very 
difficult to move men and material, and a line 
across which it is difficult to keep in touch. 
J 
The streams on either side especially mark the 
lines along which communication across the 
mountains is possible by road or by railway. 
Now, as the streams proceed down towards 
the foot-hills they unite in larger streams and more 
open valleys as at the points 5 — 6, e — f , and later 
on these new main streams unite in their turn 
before reaching the plain, as at the points g and 7. 
Now it is evident that an army forcing its 
way across the mountains from the plains at 
M — ^N tow^ards the plains K — K, when it has 
reached the crest X — Y and passed the four passes 
at the heads of the streams, is hampered in its 
movements because each portion has for some time 
been separated from the rest by the lateral or 
secondary ridges which come down from the cen- 
tral range towards the plains on either side. 
When it begins to go down the further slope 
towards K — K, pressing the defensive before it, 
these conditions remain unaltered until the first 
of those points is reached at which the streavis 
join. 
Supposing, for .instance, in the above 
diagram the enemy, advancing from a direction 
A, has made itself the master of all four passes 
1, 2, 3, and 4, and is already beginning to get down 
on the further slope. And supposing the front it 
has managed to occupy by a certain date is repre- 
sented by the line of crosses in the accompanying 
sketch. The four columns which are pressing 
down the four valleys a, b, c, d, will have various 
fortunes. Some will probably be able to go 
forward faster than others. Let us suppose 
that for some reason the progress is more 
rapid towards the X end than towards the 
Y end, and that after a few more days' 
fighting the front is represented by such a line 
as the line of dots on the accompanying sketch. It 
will be observed that the force which is fighting 
its way down valley a is very close to the point e, 
where the two streams a and b join. When the 
advance gets to e it luill cut off the retreat of the 
enemy still ojyeraiing in valley h. For that enemy 
to try to get away towards valley c across the 
lateral ridge which separates the two valleys vfiU 
be difficult or impossible. Therefore, as the 
advancing force coming down valley a gets nearer 
and nearer to e, the enemy force in valley b is in 
greater and greater peril of finding itself cut ofF 
from food and munitions altogether. If it is to 
save itself it must fall back ; and under the mere 
threat it would do so rapidly. 
Therefore a successful advance along valley 
a is enough, when it has been sufficiently pushed 
forward, to clear at once valley a and valley b 
of opposition. Even, therefore, if the enemy in 
valley b has been able to keep up a much better 
defence than in valley a, the lack of success of the 
enemy in valley a has the effect of neutralising his 
success in valley b, and the last state of the front of 
both armies will be that of the dashes. The appear- 
ance of the invaders at e only from the one valley, 
a will automatically give control to the invader of 
both passes 1 and 2 and of both the roads leading 
down from them. 
The process continues. No matter how well 
the defensive keeps its end up at the Y end of the 
chain, if the invader at the X end pushes down to 
the point G, where the streams all unite, ha 
threatens with destruction the defensive far up 
valley c and valley d, and it must fall back rapidl/j 
if it IS not to be destroyed. In effect, the mere pre- 
sence of the invader at E will almost certainlr 
make the defensive towards Y begin falling back 
rapidly, and long before the invader is at G his 
advance will have automatically uncovered the 
^hole of the mountain belt and the defensive will 
have been forced back to the line K — K. 
THE 
THE 
DOUBLE THRUST" OF 
OPPOSING ARMIES. 
Bearing all these principles in mind, we can, 
by examining the actual points in the Carpathians 
during the last three weeks, discover how matters 
stand. The Russian and Austro-German armies 
now at issue in these mountains lie opposing each 
other upon a line which makes an angle with and 
