also a keen appreciation of the nature of the country round about the target. Observation of fire may be truly said to be an art, in that it comes naturally to some people, whilst others may spend a lifetime in its practice without ever becoming proficient. The second part of an observation officer's duty, that of keeping a general watch on the ground spread out in front of him, is considerably easier, as it only requires a keen eye and a good memory. After a little practice, it is soon found that the apparent changeless calm of a deserted land is in the highest degree deceptive. Although they are utterly invisible, that land is thickly populated with hidden troops, whose object it is perpetually to turn every feature of it, natural and artificial, to the best possible use for attack or defence. The ruins of a barn stand some little way back from the enemy's line, roofless and abandoned. The telescope shows it to have some part of its walls yet standing, and within them a ladder. Now ladders are precious things in a strip of country where everything is made to serve a useful purpose. Examine the place daily and perhaps at dawn a single figure may be seen scurrying up the ladder, or perhaps its position may have altered slightly. For weeks, perhaps, one has noticed a dilapidated house, so broken down that through the shell-holes that breach the front wall one can see the horizon beyond. Yet one morning one of these shell-holes shows dark, or perhaps a new one has appeared higher up, although no battery has been seen to fire at it. A flock of starlings pours suddenly from the stump of what was once a church tower, and for a long time the birds circle in clamorous flight about it, seemingly afraid to re-enter their accustomed haunt. Hints, all of these, indicating that some use is being made of these places, either as observation stations or snipers' posts.