For many years my neighbor and best friend was a mason who specialized in Rumford fireplaces. I helped him build a bunch of them including my own. Over beers and many marijuana cigarettes I listened to him expound on the wonders of Count Rumford and his marvelous fireplace. Mostly I mixed mortar, toted and cut bricks, and broke stone into layable pieces with his ridiculous 18 pound stone maul.
But I learned a lot about fireplaces.
Eventually masonry fireplaces were mostly replaced with prefab units and natural stone replaced with manufactured stone molded nicely into face and corner pieces rather than the pile of boulders we usually started with. When the fireplace business floundered he became a general contractor(failed at that and is now a building inspector) and I preferred carpentry over the trowel trades. These days it's hard to find a mason that even knows how to build a fireplace, much less the Rumford firebox. Kudos go to Loggy for keeping the memory of Count Rumford alive a little longer.
"Be yourself; everyone else is already taken."— Oscar Wilde