Hartley Harecourt

 was an inventor who had a house train in his house. He forgot that McCallum was murdered when Henry Gordon Jago and George Litefoot arrived to investigate the murder. He often went to his club for weeks at a time. He tested the potentiation potion on McCallum. He combined the work of Hetty Kindred and Jasper Harcourt. He hoped to improve man kind. Jago became his next subject of interest. (AUDIO: The Case of the Missing Gasogene)