The .36 caliber Savage Navy is one of the many revolvers that saw purchase and martial use during the US Civil War – and in this case, martial use on both sides. About 13,000 Savages were bought by the Union army and navy, and another 11,000 were sold commercially. Many of those commercially-sold guns were later smuggled through the lines and used by Confederate troops.
Ultimately production of the Savage ended after 1863, because the Union opted to standardize on .44 caliber instead of the .36 caliber that Savage was tooled up to produce. The retooling costs were too high for the company to change over, so they dropped the gun from production (it was already a tough sell to the military, at 35%-50% more expensive than competing Colt and Remington revolvers).
Mechanically, the Savage has several forward-looking features – most notably its quasi-double-action system. It has a traditional trigger, and also a ring trigger just below. The ring trigger is actually a cocking lever, which both cocks the hammer and rotates the cylinder. The top trigger is then used to fire. This allows easy rapid fire without changing one’s grip to cock the action, although it requires some practice to operate smoothly and feels quite odd to someone not used to working two separate “triggers” in sequence.