Note 10 — Chapter VII · EMPLOYMENT OF ARTILLERY IN WAR.
Reading edition
Supposing that guns and target are on the same level, then to guns 60 yards in rear of a crest and 16 feet below it all ground is dead within 3,000 yards; if 9 feet below it all ground is dead within 2,000 yards; if 3 feet below it all ground is dead within 1,000 yards.