into the chimney rather than lingering and often choking the residents. Many fashionable London houses were modified to his instructions and became smoke-free as well as more efficient. Thompson became a celebrity when news of his success became widespread. In an age when fires were the principal source of heat, this simple alteration in the design of fireplaces was copied widely. Usage Rumford fireplaces were common from 1796, when Count Rumford first wrote about them, until about 1850. Jefferson had them built at Monticello, and Thoreau listed them among the modern conveniences that everyone took for granted. There are still many original Rumford fireplaces, often buried behind newer renovations. He also invented a cast iron stove, also known as the Rumford stove, which competed successfully with the famous Franklin stove. Both devices gave much more control over the air flow into the fire, and were much more efficient users of fuel. Such stoves were expensive, but saved so much fuel as to justify the cost of installation very quickly. They in turn inspired the development of the kitchen range, also made in cast iron, which gave yet more control of the fire and also was used directly for cooking purposes. References Bibliography G I Brown, Count Rumford: The Extraordinary Life of a Scientific Genius, Sutton Publishing (1999). External links Dr. Hugh C. Rowlinson "The Contribution of Count Rumford to Domestic Life in Jane Austen’s Time" Fireplaces American inventions Architectural elements Heating, ventilation, and air conditioning