Even though direct fire upon visible targets was increasingly rare as the war progressed, the Field Artillery Training manual notes that visual training is important to the success of reconnaissance, gun-ranging, and communication.
Visual training consisted essentially of three elements, what we might call accurate vision, first, accurate judgment of distances, second, and accurate observation, third.
Training in accurate vision is prescribed thus:
The men should be taken to some ground with a good view all round, and each in turn questioned as to what he makes of distant objects such as men, cattle, bushes, rocks, &c.; his answers being checked with field glasses by the instructor. These practices should be repeated till the men are proficient at picking out objects under varying circumstances of light, atmosphere, background and surroundings. (1)
One crucial point of this accuracy is estimating the distance of an object. It will usually appear closer when observed in bright light, the manual notes, or when the sun is behind the observer, or if he is looking up or down hill or across snow or water. On the other hand, the object will seem farther away if seen against a dark background or over dips and rises in the landscape, or when the light is in the observer’s eyes.(2)
“Objects dimly seen at evening,” notes the manual, “and in misty weather, appear more distant and larger than in reality.” (2)
Bairnsfather underlines the life-or-death importance of accurate vision for reconnaissance in the field. The caption for the first panel reads “Of course, personally I don’t think there is anyone there.” “Nor do I.”
And for the second:
“Thinking it over subsequently in [hospital in] Boulogne, — an impression of overcrowding predominates in recollections of ‘straightening’ that bit of the line.” (3)
(1) Field Artillery Training. HMSO. 1914. 381.
(2) Field Artillery Training. 382.
(3) Bairnsfather, Bruce. More Fragments from France. Vol 2. nd. 39.