Client 1 - Ale & Cakes Copper Mine.

They need a new engine to pump water out of the mine to greater depths than before, so they can get to deeper veins of copper. Times are hard - the Cornish copper trade is being hit badly by cheap copper coming from Anglesey, so the adventurers need to save money, but they need to go as deep as they can to extract as much copper as possible.

Client 2 - Peter Drinkwater.

He needs an engine to power his new cotton mill. He has money to invest, and the cotton trade is doing well. However he needs his engine quickly, as there are lots of mills in Manchester and competition is fierce. The engine needs to work all day to power the looms. He is a merchant, with no engineering experience.

Client 3 - Sir George Henry Freeling.

As Assistant Secretary, he is in charge of ordering steam boats to deliver the mail around the coast of Britain. New boats are needed to work on a new route from Liverpool - they must be fast, much faster than the old sailing ships. The service also has to be efficient - the post has to be delivered on time, and the Post Office are being criticised for not running their boats efficiently. He has worked with steam boats for many years, and knows a lot about their engines and design.

Client 4 - Mr. Sobotker.

He needs an engine to power the sugar cane-crushing mill on his plantation. The sugar cane is crushed in the mill after it has been harvested, to extract the juice for making sugar, and getting rid of the "trash". Therefore the engine will only be used for a short time each year, when the cane is harvested. Moreover the price of sugar is dropping, and the price of the slaves who work on the plantation is rising. Therefore he does not have much money to spend, especially as his plantation is on St. Croix, and shipping an engine from England is difficult and costly, as parts have to be transported in cramped sailing ships. He is a merchant, with no engineering experience.

Was it right for Boulton and Watt to sell their steam engines to help slave owners to run their plantations?

Steam engines were used to crush sugar cane and slowly replaced rolling mills powered by windmills, waterwheels and animal power. From the early 19th century, plantation owners like Mr Sobotker of St Croix, were facing a squeeze on their profits. Steam engines, though expensive, at about £1,000, reduced running costs. Steam technology was more reliable compared to other sources of energy. It also used a readily available fuel – trash, the waste from crushed cane – which cost plantations nothing.

Supporters of the anti-slavery movement were interested in the possibilities of steam power for reducing the need for slaves. Samuel Whitbread, on behalf of William Wilberforce, wrote to Boulton and Watt about this matter in 1789. Watt is on record as an opponent of slavery. Writing in 1791, he hoped that the system “so disgraceful to humanity” would be “abolished by prudent though progressive measures.”

In reality, the impact of steam engines on reducing the need for slaves was small. An animal mill might require five slaves whilst a steam-powered one required three. Most slaves were engaged on other plantation tasks, such as cane cutting, that were not easily mechanised. There is no evidence in the commercial correspondence of Boulton and Watt that the anti-slavery argument was ever used to justify sales. The partnership was a commercial company, which could only survive by selling in a competitive environment. Another business, Fawcett and Littledale in Liverpool, also marketed steam engines to crush cane. Between 1778 and 1825, Boulton and Watt sold 119 steam engines to the Caribbean, the first one in 1803. All of their other overseas sales combined in this period reached 110. The market in the West Indies was therefore central to their economic activity.

The potential conflict between ethical and commercial considerations in relation to slavery was, nevertheless, a live issue in the late 18th and early 19th centuries. It is explored on www.revolutionaryplayers.org.uk in the Theme section of the website under The Midlands and the World and through an interactive Learning Journey. A survey of the economics of steam power in the West Indies is provided in Jennifer Tann, “Steam and Sugar: The Diffusion of the Stationary Steam Engine to the Caribbean Sugar Industry 1770-1840”, History of Technology, vol. 19, 1997, p 63-84.