Spectral lines: Walking the technology-transfer tightrope

Historians tell us that, in the United States at least, the need to protect information about military technology was virtually nonexistent prior to 1860. Before that, all adversaries used essentially identical weapons, so there were no secrets. But during the Civil War torpedoes and mines arrived on the scene. Inventors had a field day devising ingenious designs, and although many of them were never reduced to practice, military and naval leaders were concerned about keeping both real and potential designs from the enemy.