My Loyalist Ancestors - Benjamin Thompson AKA Count Rumford

 

The Count Rumford birthplace in Woburn, Massachusetts

This is the second blog post on a Loyalist ancestor I have written this year for the 250th anniversary of the United States.  Benjamin Thompson is my first cousin, six generations removed.  His mother, Ruth Simonds (b. 1730) is the sister of my 5th great grandfather, Caleb Simonds (1720 - 1811).  Benjamin Thompson was born 26 March 1753 in Woburn, Massachusetts in the house of his grandfather, Captain Ebenezer Thompson.  He attended the local schools until he was eleven years old, when he was sent (along with his young friend and neighbor Loammi Baldwin) to Medford to study mathematics, astronomy and science.  

At age 13 he was bound as an apprentice to a Salem merchant, John Appleton.  Thompson went home to Woburn soon after because Appleton lost his business when the relations between the colonies and England became strained. Then he taught school in Wilmington in 1768 and 1769.  Later in 1769 he again studied science (anatomy and physiology) under Dr. John Hay, a doctor in Woburn. In 1770 he studied at Harvard with his friend Loammi Baldwin.  In 1772 he began to teach school in Rumford (now Concord, New Hampshire). 

By 1772 he married Sarah Walker, the widow of Benjamin Rolfe, and daughter of Rev. Timothy Walker of Rumford. She was a very wealthy woman, age 33, and Benjamin Thompson was only 19 years old. He joined the New Hampshire regiment, and had to chose sides to be an American or a Loyalist.  When he was denied a commission to be an officer in the Continental army he joined the British. Benjamin and Sarah had one daughter, Sarah, born 18 October 1774. 

When the British evacuated Boston on 17 March 1776 he fled to England and left his wife in New Hampshire. He was elected to the Royal Society of Science in 1779, returned to America as an officer in 1781 - 1782, and was knighted in 1784.  Then he left England for Germany, where he served the Prince of Bavaria for 18 years, where he was made a count of the Holy Roman Empire. He chose to be named Count Rumford, after the town in New Hampshire.

In 1803 he settled in France where he remarried to the widow of the French chemist Lavoisier.  His new wife was Anne Marie Pierette Paulze. While in France he invented a calorimeter, a photomete, and a drip coffee maker.  His studies of heat lead him to be the first to understand that heat was a form of motion.

He endowed the Rumford Medals at the Royal Society, and the Rumford Medals at the American Academy of Arts and Sciences, and the Rumfor chair of science at Harvard College (now Harvard University). He, along with Sir Joseph Banks, founded the Royal Institution of Great Britain.  He also made some practical inventions such as central heating, the smokeless chimney, the kitchen oven, the first pressure cooker, and other. His name lives on for the invention of the Rumford Fireplace, which reflected more heat back into the room than previous versions of fireplaces. 

As Count Rumford in Europe, he had several love affairs, including a woman Victoire Lafevre (his housekeeper) who bore him a son,  and the Countess Baumgarten with whom he had another daughter named Sophia, born in 1798.  Count Rumford also had an affair with her sister, the Countess Nogarola.  

Benjamin Thompson, AKA Count Rumford, died 21 August 1814 in Auteil, France and is buried there. His epitaph reads "Benjamin Thompson, Conte De Rumford. The celebrated physicist and enlightened philanthropist, whose discoveries on light and heat made his name illustrious and whose work to help the poor will always be dear to the friends of humanity."

President Franklin D. Roosevelt said that Sir Benjamin Thompson, Count Rumford, was "one of the three greatest minds America has produced" (the others were Benjamin Franklin and Thomas Jefferson).  

By Thomas Gainsborough - Corel Photo CD, MASTERS I, Public Domain, https://commons.wikimedia.org/w/index.php?curid=9516763

For the truly curious:

Previous blog posts on Benjamin Thompson, Count Rumford:

"Two Cousins", 17 May 2012:  https://nutfieldgenealogy.blogspot.com/2012/05/two-cousins.html   

"The Count Rumford House", 14 May 2012:   https://nutfieldgenealogy.blogspot.com/2012/05/count-rumford-house.html   

"Colonel Loammi Baldwin", 24 October 2013:   https://nutfieldgenealogy.blogspot.com/2013/10/colonel-loammi-baldwin.html  

Memoir of Sir Benjamin Thompson, Count Rumford, with notices of his daughter, (with an edition of Rumford's complete works) by George E. Ellis, published by the American Academy of Arts and Sciences, Boston, 1875. 

Sir Benjamin Thompson, Count Rumford and the Royal Instituation, by the Royal Society, 1999. 

White Knight, Red Heat: The many lives of Benjamin Thompson, Count Rumford, by John and Mary Gribbin, 20023

Benjamin Thompson at Wikipedia:   https://en.wikipedia.org/wiki/Benjamin_Thompson 

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To cite/link to this blog post: Heather Wilkinson Rojo, "My Loyalist Ancestors - Benjamin Thompson AKA Count Rumford", Nutfield Genealogy, posted September 15, 2026, ( https://nutfieldgenealogy.blogspot.com/2026/09/my-loyalist-ancestors-benjamin-thompson.html: accessed [access date]).