Bourbon fuse
This type of detonator was screwed into round grenades to ensure they exploded at the appropriate moment. The purchase of this ‘secret weapon’ by the Dutch government caused a parliamentary crisis in the Netherlands in 1849, due to its astronomical price. The device was sometimes referred to as the Bourbon fuse, because its inventor, Karl Wilhelm Naundorff, claimed to be Charles Louis de Bourbon, and heir to the French throne.