These instructions for fireballs were accompanied by a paper which described them as ‘Watson’s receipt for fireball received [by the Home Office] 29th January 1820′. James Watson was one of the Cato Street conspirators and already known to the authorities for previous radical activities. This information was probably provided by a government spy. (Catalogue reference HO 44/4/20)
Transcript
Fire Ball
Take 2oz Rosin
2oz Mutton suit
2oz Horse Turpentine
Melt together and when beginning to cool add 2oz powdered salt petre. Make it into a ball with a fuse fixed in from the centre composed of brown paper smeared with the above ingredients without the salt petre and rolled up and firmly fixed into the ball.
[Rosin: solid form of resin obtained from pines
Mutton suit: animal fat/suet
Horse turpentine: used to harden the soles of horses’ hooves
Salt petre: natural solid source of nitrogen, potassium nitrate used in fertilizers, for tree stump removal, and fireworks]