us, and their blast is clearly shown by the film of smoke and dust which
hurries into the air. The haze makes a complete screen between us and
the battle.

7.15 a.m.--Our fire has become noticeably hotter. Some of us thought it
had relaxed slightly after the first ten minutes. I doubt if it really
did--probably we were growing accustomed to the sound. There is no doubt
about its increase now. We can hear the _crump_, _crump, crump_ of
heavy explosives almost incessantly. I fancy our heavy trench mortars
must have joined in.

7.20 a.m.--Another sound has suddenly joined in the uproar. It is the
rapid detonation of our lighter trench mortars.[1] I have never heard
anything like this before--the detonation of these crowds of mortars is
as rapid as if it were the rattle of musketry. Indeed, if it were not
for the heavy detonation one would put it down for rifle fire. Only
eight minutes now, and the infantry goes over the parapet along the
whole line.

[1] Note.--What I took for the sound of trench mortars was almost
certainly that of the British field guns. These heavy Somme bombardments
were then a novelty, and the idea that field guns could be firing like
musketry did not enter one's head. What I took for the sound of heavy
trench mortars was also, certainly, that of German shells.

7.27 a.m.--The heaviness of the bombardment has slightly decreased. A
large number of guns must be altering range on to the German back lines
in order to allow our infantry to make their attack. The hills are
gradually becoming clearer as the sun gets higher, but the haze will be
far too thick for us to see them go over.