German infantry were under constant observation from aircraft and balloons, which directed huge amounts of artillery-fire accurately onto their positions and made many machine-gun attacks. Infantry Regiment 68 ordered that men in shell-holes should dig fox-holes or cover themselves with earth for camouflage and sentries were to keep still, to avoid being seen. The German air effort in July and August was almost wholly defensive, which led to harsh criticism from the ground troops and ineffectual attempts to counter Anglo-French aerial dominance, which dissipated German air strength to no effect. A fiasco occurred on 22 July, when photographic reconnaissance aircraft were sent to engage a British aircraft, which turned out to be a German Albatros. The effect of Anglo-French artillery observation aircraft was considered "brilliant", "annihilating" German artillery and attacking infantry from very low altitude, causing severe anxiety among German troops, who began to treat all aircraft as Allied and led to a belief that Anglo-French aircraft were armoured. Attempts to help the infantry by redeploying German aircraft, resulted in many losses for no result and further undermined relations between the infantry and (Imperial German Flying Corps). German artillery units preferred direct protection of their batteries, to artillery observation flights which led to more losses, as German aircraft were inferior to their opponents as well as outnumbered. Slow production of German aircraft exacerbated equipment problems, which led to German air squadrons being equipped with a motley of designs, until the arrival of Jagdstaffel 2 under Oswald Boelcke, equipped with the Halberstadt D.II, which regained a measure of air superiority in August.