Early Watt engines had a duty of 20 million, and later ones over 30 million.

Early Watt engines equipped with high-pressure steam improved this to 65 million.

Cornish miners were buying a lot of Watt engines.

He also probably invented the sun and planet gear used to obtain rotary motion on Watt engines.

Although the Watt engine powered cotton mills and a variety of machinery, it was a large stationary engine.

Watt finally considered the design good enough to release in 1774, and the Watt engine was released to the market.

Older Watt engines were updated to conform.

In 1804 a second Boulton and Watt engine was added alongside the 1779 engine.

The Watt engines were of Watt's early single-acting atmospheric designs.

This was soon augmented by three Boulton and Watt engines to provide power for the increasing number of spindles.