Tartaglia on ballistics, 16th century. Surveyors (lower left) using geometric quadrants with plumb-bobs to measure the angle to a cliff-top castle. This method of surveying establishes the distances involved and allows calculation of the trajectory of missiles used in artillery bombardments. Published in 'La noua scientia' (The New Science, 1550) by Italian mathematician and engineer Niccolo Tartaglia (1499-1557).