sturbed, will alter their ranges, four times out of five,
which is exactly what we want them to do.

The next bursts will be hundreds of metres below or above us,
whereupon we show signs of great uneasiness, and the gunners, thinking
they have our altitude, begin to fire like demons. We employ our
well-earned immunity in preparing for the next series of batteries, or
in thinking of the cost to Germany, at one hundred francs a shot, of
all this futile shelling. Drew, in particular, loves this
cost-accounting business, and I must admit that much pleasure may be
had in it, after patrol. They rarely fire less than fifty shells at
us during a two-hour patrol. Making a low general average, the number
is nearer one hundred and fifty. On our present front, where aerial
activity is fairly brisk and the sector is a large one, three or four
hundred shells are wasted upon us often before we have been out an
hour.

We have memories of all the good batteries from Flanders to the Vosges
Mountains. Battery after battery, we make their acquaintance along the
entire sector, wherever we go. Many of them, of course, are mobile, so
that we never lose the sport of searching for them. Only a few days
ago we located one of this kind which came into action in the open by
the side of a road. First we saw the flashes and then the shell-bursts
in the same cadence. We tipped up and fired at him in bursts of twenty
to thirty rounds, which is the only way airmen have of passing the
time of day with their friends, the enemy anti-aircraft gunners, who
ignore the art of _camouflage_.

But we can converse with them, after a fashion, even though we do not
know their exact position. It will be long before this chapter of my
journal is in print. Having given no indication of the date of
writing, I may say, without indiscretion, that we are again on the
Champagne front. We have a wholesome respect for one battery here, a
respect it has justly earned by shooting which is really remarkable.
We talk of this battery, which is east of Rheims and not far distant
from Nogent l'Abbesse, and take professional pride in keeping its
gunners in ignorance of their fine marksmanship. We signal them their
bad shots--which are better than the good ones of most of the
batteries on the sector--by doing stunts, a barrel turn, a loop, two
or three turns of a _vrille_.

As for their good shots, they are often so very good that we are
forced into acrobacy of a wholly individu