“Entirely useless by breaking off the Trunnions”

Yesterday I started quoting a 29 Apr 1776 letter from the Rev. Dr. Samuel Cooper to Samuel Adams about Boston’s defenses soon after the British military left.

That letter goes on to say:

The Enemy employ’d no little Time in…destroying the Guns: The Trunnions of all of which, except 8 or so, they entirely knock’d off, besides spiking up the Touch holes in the most effectual Manner.

“Trunnions” was a term technical enough not to appear in Dr. Samuel Johnson’s dictionary. Merriam-Webster now defines them as the pivots on which something can be rotated or tilted, particularly the “two opposite gudgeons on which a cannon is swiveled.” (And it defines “gudgeons” as pivots.)

This overhead view of a cannon might convey the information better.

A gun carriage held a cannon by the two horizontal trunnions. They provided the fulcrum that allowed gunners to point the cannon up or down. A cannon without its trunnions was a heavy metal tube, very hard to mount and impossible to aim. Or, as Gen. George Washington deemed the broken guns left behind in Boston, “entirely useless.”

British artillerists broke trunnions to keep the rebels from having useful weapons. In Concord on 19 Apr 1775, Ens. Henry DeBerniere reported, “Capt. [Mundy] Pole of 10th regiment…knock’d the trunnions off three iron 24 pound cannon and burnt their carriages.”

With little other choice, the Continental Army still tried to use such damaged artillery pieces. Dr. James Thacher reported that the army started out with “a few old honey-comb iron pieces, with their trunnions broken off.” The doctor was pleased when Capt. John Manley and Col. Henry Knox brought in some intact guns.

Given that expertise, and necessity, on 24 March Washington expressed hope that Boston’s broken and spiked cannon “may be made serviceable again.” But how?

TOMORROW: A genius appears.