| Description | James Watt’s statement in the Bristol newspapers in 1782 of the six features of his steam engine which he considering his exclusively put Jonathan Hornblower in a difficult position. His engines clearly used five of the features that Watt listed, and therefore his engines infringed Watt’s patent. Technically therefore, Hornblower could not erect engines under his own patent of 1781 until Watt’s had expired. However, Hornblower’s patent was only protected for fourteen years, whereas Watt’s was protected until 1800 by the Act of Parliament of 1775 which extended it.
Despite having got the Radstock engine in good working order and despite active soliciting, orders for Hornblower’s engines were initially not forthcoming. However in 1791 he erected in two successful engines, at Tincroft Mine and Swanpool. This, coupled with the unfavourable situation of his patent, led Hornblower to apply to Parliament to have his own patent extended. Boulton & Watt, concerned about the effect Hornblower might have on their lucrative Cornish market, mounted a campaign of opposition to Hornblower’s bill, and his bill was rejected at the second reading. He formally withdrew it in May 1792. However Boulton & Watt never took any specific legal action in the courts to prove that Hornblower’s engines infringed Watt’s patent, despite the fact that he continued to erect engines. The only time that a court case against Hornblower was considered was in 1799/1800, to give Boulton & Watt more legal power in their struggles to secure payments that were being withheld by several Cornish mines (see MS 3147/2/52). However the payments were duly made and the action against Hornblower was dropped.
This bundle contains letters and papers from Boulton & Watt’s opposition to Hornblower’s bill in the Commons in 1792, as well as a few earlier letters about Hornblower’s first engine at Radstock Colliery. The original contents of the bundle were listed on its cover, but at some point further material was added. These additional items are described at the end of the list.
For further letters about the Radstock engine see the bundle of "Papers relating to the obtaining of Horner’s Patent & proceedings at Radstoke to 1791" (MS 3147/2/33). For papers relating to premiums demanded from mines that erected Hornblower’s engines, see the bundles of papers relating to Cornish Law Cases (MS 3147/2/51—MS 3147/2/60). For drawings of Jonathan Hornblower’s engines, see "Sketches and Descriptions of Pirate and Rival Engines" (MS 3147/2/62) and "Drawings of Engine Designs by James Watt, Bull and Hornblower’s Engines, Dutch Windmill etc.", Portfolio MS 3147/5/1339b. |