Did James Watt’s patent(s) really delay the industrial revolution?

Sean Bottomley,Max Planck Institute for European Legal History

Newcomen’s atmospheric engine

The second clause of Watt’s 1769 specification

The fourth clause of Watt’s 1769 specification

This clause allegedly allowed Watt to block the development of high pressure steam engines. This is a common view in economic history:Watt’s patent ‘effectively blocked the development of a high pressure engine, even though Watt himself firmly opposed such engines hampering or altogether blocking technological progress’ (Mokyr, 1990)

Cultural history: Watt’s patent was responsible for ‘hampering or altogether blocking technological progress’ (Marsden, 2002)

And technological history: ‘Boulton & Watt … closed off certain avenues of steam engine development … it comes as no surprise that the French developed high pressure engines on a larger scale earlier than the British’ (Tann, 1979)

The example of Watt’s patent has also been seized upon by Boldrin & Levine, and is discussed over the first chapter of their 2008 book Against Intellectual Monopoly. Boulton & Watt apparently ‘used the patent system as a legal cudgel with which to smash competition’, and by preventing the development of high-pressure steam engines, ‘most likely delayed the industrial revolution by a couple of decades’ (2013)

They also introduce some additional claims. Firstly, that Boulton & Watt rarely manufactured engines themselves, but that their ‘activity consisted primarily of extracting hefty monopolistic royalties through licensing’.Secondly, that the defence of his 1769 patent diverted Watt’s from engaging in inventive activities himself (‘substantial portion of his energy was devoted to fending off rival inventors’)

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Boulton & Watt's manufacturing output, 1779-1800

Year Engines erected Value of manufactured output1 Value of manufactured output by engines erected1779 10 £923 £921780 10 £480 £481781 4 £92 £231782 2 £582 £2911783 10 £344 £341784 15 £806 £541785 19 £1,515 £801786 21 £2,348 £1121787 11 £3,639 £3311788 14 £4,200 £3001789 20 £3,594 £1801790 21 £3,800 £1811791 25 £9,858 £3941792 18 £9,866 £5481793 17 £11,831 £6961794 13 £9,789 £7531795 26 £5,281 £2031796 31 £15,295 £4931797 21 £15,168 £7221798 23 £17,847 £7761799 47 £23,139 £4921800 47 £28,167 £608

Boulton & Watt’s manufacturing output, 1779-1800

1 Value of manufacturing output for October to September

The poppet valve, c.1774

Sun and planet gearing, 1781

Parallel Motion, 1784

Centrifugal governor, 1788

Hornblower’s compound engine, 1781

Sixthly, that the condensed vapour shall not remain in the steam-vessel in which the steam is condensed, I collect it into another vessel.

Even despite Hornblower’s use of a separate condenser, both sides acknowledged that the use of high pressure steam contravened Watt’s patent:

In 1792, for example, in their published opposition to Jonathan Hornblower’s application to Parliament for an extension to his own patent term, they asserted that one of the principle contributions of Boulton and Watt was to develop ‘the piston [which] is pressed down by the expansive power of steam; and not (as in Newcomen’s) by the weight of the atmosphere’

Hornblower himself appears to have acknowledged this – in a letter written in 1789 to his uncle he admitted that in his engine ‘the mechanism is similar to Watt’s in most respects’, one of which was that ‘steam is convey’d thither in a state stronger than the atmosphere and acts upwards with a force’

Why did Boulton & Watt wait for 18 years before enjoining Hornblower?

1) In the 1780s, Hornblower’s engine was technically and commercially uncompetitive, making “so wretched a performance as not to equal an Old Usual Engine” (John Southern in 1782)

2) Watt’s 1769 patent was poorly specified – especially the fourth clause relating to the expansive use of steam (Justice Rooke: he “could [not] maintain an action for breach of these articles’”). He needed to wait before successfully prosecuting more egregious infringers, before turning to Hornblower

3) It was always Watt’s intention to secure royalty payments from mines using Hornblower’s engine – which he was ultimately able to do (collecting nearly £10,000).

A hypothetical comparison of Boulton & Watt’s royalty charges, and Hornblower’s

Fuel costs with an atmospheric engine £ 2,000Fuelcosts with a Watt engine £ 1,000Royalty charged as one third of fuel savings £ 333Total costs with a Watt engine £ 1,333

Fuel costs with a Hornblower engine £ 850Royalty charged as one third of fuel savings £ 50Total costs with a Hornblower engine £ 900

Total costs advantage with a Hornblower engine £ 433