"A whiff of grapeshot" is an idiom meaning a brief but impactful display of force, often used to quell dissent or show overwhelming power.

Grapeshot:
This refers to cannon ammunition containing a cluster of small balls, designed to be fired at close range to inflict casualties on a large number of targets.


Napoleon's Use:
In October 1795, during the French Revolution, a large crowd of royalists gathered in Paris, threatening the revolutionary government. Napoleon, then a young artillery officer, was given command to suppress the revolt. He famously used cannons loaded with grapeshot to quickly and effectively disperse the crowd.


Impact and Significance:
Napoleon's decisive action, using grapeshot against a mob of civilians, was a notable event. It demonstrated his military skills and helped solidify his rise to power.