Now to work. We understand each other, we map-lovers. The other folk have gone on to the next chapter, so we can take our time.
To face page 97
MAP II.
TRENCH LINE —·—·—·—·—·—
Now look at Map II. The River Ancre runs down west of the Thiepval ridge, through Albert, and then in a south-westerly course through Méricourt-l’abbé down to Corbie, where it joins the Somme on its way to Amiens. On each side of the Ancre is high ground of about 100 metres. The high ground between the Ancre and the Somme forms a long tableland. There is no ridge, it is just high flat country, from three hundred and thirty to three hundred and forty feet, cultivated and hedgeless. Now look at Fricourt. It is a break in this high ground running on the left bank of the Ancre, and this break is caused by a nameless tributary of that river, that joins it just west of Méaulte. And now you will see that this little streamlet was for over a year and a half the cause of much thought and labour to very many men indeed: for this stream formed the valley in which Fricourt lies; and right across this valley, just south of that unimportant little village, ran for some twenty months or so the Franco-German and later the Anglo-German lines.
Now look at the dotted line (—·—·) which represents the trenches. From Thiepval down to Fricourt they run almost due north and south; then they run up out of the valley on to the high ground at Bois Français (a small copse, I suppose, once; I have never discovered any vestige of a tree-stump among the shell-holes), and then abruptly run due east. It is as though someone had appeared suddenly on the corner of the shoulder at Bois Français, and pushed them off, compelling them to make a détour. After five miles they manage to regain their direction and run south again.
It is these trenches at Bois Français that we held for over four months. I may fairly claim to know every inch of them, I think! It is obvious that if you are at Bois Français, and look north, you have an uninterrupted view not only of both front lines running down into Fricourt valley, but of both lines running up on to the high ground north of Fricourt, and a very fine view indeed of Fricourt itself, and Fricourt wood. It is also quite clear that from their front lines north of Fricourt the Germans had a good view of our front lines and communications in the valley; but of Bois Français and our trenches east of it they had no enfilade view, as all our communications were on the reverse slope of this shoulder of high ground. So as regards observation we were best off. Moreover, whereas they could not possibly see our support lines and communications at Bois Français, we could get a certain amount of enfilade observation of their trenches opposite from point 87, where was a work called Boute Redoubt and an artillery observation post.
The position of the artillery immediately becomes clear, when the lie of the ground is once grasped. For field artillery enfilade fire is far most effective, as the trajectory is lower than that of heavy artillery. That is to say, a whizz-bang (the name given to an 18-lb. shell) more or less skims along the ground and comes at you; whereas howitzers fire up in the air, and the shell rushes down on top of you. To be explicit at the risk of boring:—