Henri-Joseph Paixhans developed a delaying mechanism that allowed explosive shells to be safely fired in high-powered guns, first demonstrated in trials in 1824.

The French Navy adopted the first Paixhans guns in 1841, and the weapons eventually saw use in the 1840s by France, Britain, Russia, and the United States.

Explosive shells had long been in use in ground warfare (in howitzers and mortars) and on bomb vessels against stationary targets, but they were fired only at high angles and with relatively low velocities.

Therefore, ship-to-ship combat had consisted for centuries of encounters between flat-trajectory cannons using inert cannonballs, which could inflict only local damage, even on wooden hulls.

[3] Paixhans developed a delaying mechanism that, for the first time, allowed shells to be fired safely in high-powered flat-trajectory guns.

[citation needed] According to the Penny Cyclopaedia (1858):[excessive quote] General Paixhans made important improvements in the construction of heavy ordnance, and also in the projectiles, in the carriages, and in the mode of working the guns.

General Paixhans was one of the first to recommend cylindro-conical projectiles, as having the advantage of encountering less resistance from the air than round balls, having a more direct flight, and striking the object aimed at with much greater force, when discharged from a piece of equal calibre, whether musket or great gun.

As large ships of war, particularly three-decked ships, offer a mark which can hardly be missed, even at considerable distances, and as their wooden walls are so thick and strong that a shell projected horizontally could not pass through them, an explosion taking place would produce the destructive effects of springing a mine, and far exceeding those of a shell projected vertically, and acting by concussion or percussion.While the idea was notable in the advance of artillery, metallurgy had not advanced to the level needed for safe operation.

Further work by John A. Dahlgren, and Thomas Jackson Rodman improved the weapon to use both solid shot and shell safely.

[5] In 1827, the French navy ordered fifty large guns on the Paixhans model from the arsenals at Ruelle and at Indret near Nantes.

This made a mixed armament, was objectionable as such, and never was adopted to any extent in France... My idea was, to have a gun that should generally throw shells far and accurately, with the capacity to fire solid shot when needed.