 During the mid-1830s, William Eley reinvigorated the company and began sell the "Improved Patent Wire Cartridges".In 1837 the company added percussion caps to their range and though William was killed in an explosion in 1841, his three sons helped carry on the business.His eldest son William Thomas forged an alliance with Samuel Colt, the two patenting a skin cartridge for use in the latter's revolvers.