Count Rumford, for whom the Rumford fireplace is named, was born Benjamin Thompson in Woburn, Massachusetts in 1753 and, because he was a loyalist, he left (abruptly) with the British in 1776. He spent much of his life as an employee of the Bavarian government where he received his title, "Count of the Holy Roman Empire." Rumford is known primarily for the work he did on the nature of heat.

Back in England, Rumford applied his knowledge of heat to the improvement of fireplaces. He made them smaller and shallower with widely angled covings so they would radiate better. And he streamlined the throat, or in his words "rounded off the breast" so as to "remove those local hindrances which forcibly prevent the smoke from following its natural tendency to go up the chimney..."

More About Rumford:

Rumford the Scientist
Rumford on Curiosity
Allen L. King notes
Statue of Rumford in front of Woburn Library thanks to Rick Micciulla
Other Rumford Interests and Inventions

Life and Legend of Count Rumford, Woburn Historical Commission
Rumford Birthplace National Landmark
Count Rumford, Sanborn Brown, and the Rumford Mosaic by Allen King*
Hugh C. Rowlinson "The Contribution of Count Rumford to Domestic Life in Jane Austen's Time"
Quentin Crewe on how Rumford revolutionised the restaurant kitchen*
Rumford Kitchen - 1894*
Rumford's bio, part of a nice website by Eric W. Weisstein who links the science. See Eric's book
And a Different Take