We all know the story behind Bonfire Night – the thwarted plot in 1605 to blow up the Houses of Parliament in London, led by Robert Catesby. His fellow plotters included Guy Fawkes, who was enlisted for his expertise in explosives, learnt from his time fighting with the Spanish army. The plotters were Catholic and were seeking to assassinate the Protestant King James I. In order to execute their plan, they had amassed 32 barrels of gunpowder in a vault beneath Parliament.

Gunpowder was invented in China, and it is believed that its first appearance in Europe was in the 14th century. The explosive was a frequent topic of research and discussion in the early days of the Royal Society in the late 17th century, and experimentation as to the ideal composition and method of manufacture was ongoing.

Progress was made in 1663 when Prince Rupert submitted a paper to the Society giving ‘A description of the way of making good gunpowder.’ He gives detailed instructions for preparing the three ingredients of saltpetre, brimstone and (char)coal. His method was credited at a meeting of the Royal Society with having ten times the force of the common English version of the propellant.


Opening lines of ‘A Description of the way of making good Gunpowder’ by Prince Rupert, 22 July 1663 (Royal Society RBO/2i/64)


Prince Rupert’s powder prompted a series of attempts to accurately measure its force. Robert Hooke presented an instrument for this purpose and attempted to demonstrate it to the Society, with little success. There are several accounts of attempts to demonstrate the instrument – on the first it was found to be ‘imperfect’ and on the second the barrel was broken.


‘A Description of an Instrument for Tryall of Powder’ by Robert Hooke, 9 September 1663 (Royal Society RBO/2ii/56)


Experiments continued, with Denis Papin also producing a measurement device in 1688 and Benjamin Robins in 1742:


A ballistic pendulum by Benjamin Robins, from his ‘Experiments relating to the force of gunpowder…’, 1742 (Royal Society MS/130/11/11)


Although the gunpowder used by Guy Fawkes may not have had the purity or strength of that developed 58 years later by Prince Rupert, contemporary calculations have concluded that it would have been more than sufficient to destroy the Houses of Parliament. It is likely that it would have fulfilled its aim of killing King James I and many others in the chamber, including, it is thought, Francis Bacon. Bacon’s ideas formed the guiding ethos for the founding of the Royal Society in 1660, and it is fascinating to speculate how his early demise would have changed the course of natural philosophy in the 17th century.


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