Later years

Watt retired in 1800, the same year that his fundamental patent and partnership with Boulton expired. The famous partnership was transferred to the men's sons, Matthew Boulton and James Watt Jr. Longtime firm engineer William Murdoch was made a partner and the firm prospered.

Watt continued to invent other things before and during his semi-retirement. He invented a new method of measuring distances by telescope, a device for copying letters, improvements in the oil lamp, a steam mangle and a machine for copying sculptures. Within his home in Handsworth Heath, Staffordshire, Watt made use of a garret room as a workshop, and it was here that he worked on many of his inventions.

He and his second wife travelled to France and Germany, and he purchased an estate in Wales at Doldowlod House, one mile south of Llanwrthwl, which he much improved.

He died on 25 August 1819 at his home "Heathfield" in Handsworth, Birmingham, England at the age of 83. He was buried on 2 September.

The garret room workshop that Watt used in his retirement was left locked and untouched until 1853, when it was first viewed by his biographer J. P. Muirhead. Thereafter, it was occasionally visited, but left untouched, as a kind of shrine. A proposal to have it transferred to the Patent Office came to nothing. When the house was due to be demolished in 1924, the room and all its contents were presented to the Science Museum, where it was recreated in its entirety.^[5] It remained on display for visitors for many years, but was walled-off when the gallery it was housed in closed. The workshop remains intact, and preserved, and there are plans for it to go on display again at some point in the near future.