Used on numerous expeditions to mountaintops (including Mount Everest and K2) and both poles of the Earth, its popularity is mainly due to the very astute decision of the original manufacturer's great-nephew to market it as an energy food, and to supply Ernest Shackleton's 1914-17 Trans-Antarctic Expedition.
Illingworth left the firm in 1867 to start his own firm, which remained in business until the 1980s.