Rumford fireplaces have been around for over 200 years, and there's a reason for that. They work. The basic design is a tall and shallow firebox with a streamlined throat. This effectively eliminates turbulence and draws away smoke without drawing away heat. Thus, a Rumford fireplace can be more effective than other fireplaces as a room heater while still providing the circulation and venting you need to prevent indoor pollution.
The Rumford fireplace was invented, predictably enough, by Count Rumford, from whom they take their name. The oldest document in which they are described dates back to 1796. By then, Rumford fireplaces were already common. They remained so until about 1850.
Thomas Jefferson had Rumford fireplaces install at Monticello, his palatial home. Henry David Thoreau spoke of them as a modern convenience, taken for granted by all. They can still be found in well-preserved older homes, sometimes buried behind renovations.
Born Benjamin Thompson in Woburn, Massachusetts in 1753, Count Rumford left the American colonies in 1776. As a British loyalist, he did not desire to become caught up in the war, surrounded by revolutionary neighbors. He eventually settled in Bavaria as a government employee. His title of count, more specifically "Count of the Holy Roman Empire" was conferred.
Today, though, we know him best for his work on the nature of heat.
Rumford began applying his knowledge of heat to fireplaces while still in England. He experimented with small, shallow coverings with wide angles, reasoning that this would radiate the heat more effectively. He streamlined the neck of the fireplace, where the smoke starts to head up the chimney. His goal was to remove any hindrance that might block the smoke and divert its path back into the room.
Once he had perfected his design, Count Rumford wrote two papers on the subject. But even prior to that, people had begun copying his design. The papers, written in 1796 and 1798 provide both the theoretical and the practical details behind his design. The papers were widely disseminated and eagerly consulted by designers and builders looking for a more fuel-efficient and smoke-free way to heat indoor spaces. The Rumford fireplace soon became the worldwide standard.
Count Rumford's essays are available in printed form in The Collected Works of Count Rumford; Vol. 2; Sanborn Brown, ed.; Harvard Univ. Press; 1969.
There are several additional sources online that offer information about Count Rumford and the fireplace type that bears his name. If you wish to do some further reading, you may want to reviews these reources:
Rumford Fireplaces: Offers an extensive list of articles on Rumford fireplaces, the man who designed them, and photos of the fireplace.
Count Rumford: provides an overview of the life o0f Count Rumford.