VISIBILITY TABLE BETWEEN DAWN AND SUNRISE

Hour                Time before Sunrise                objects discerned

Hrs.   Mins.

2.5                               1         44         Break of dawn.

2.35                             1         14         Read watch.

2.45                             1         4           See chalk trenches at 600 yards.

2.50                             –          59         See earth trenches at 600 yards.

3.20                             –        29         Distinguish trenches a mile off.

No aeroplane up.         See aeroplane easily flying at 3000’

(Looks black cannot see colours.)

3.15                            –         34          Distinguish men’s heads above trenches at 100 yards.

3.25                          –        24          See foresight of rifle and men at 300 yards    sufficiently easy for accurate firing.

3.40                             –         9            Perfect light to see any objects.

The morning was an average summer morning.

Sky with thin covering of clouds.

June 3^rd 1916