William Hasledine Pepys FRS: A life in scientific research, learned societies and technical enterprise

In a long and many-sided career, William Hasledine Pepys (1775-1856) contributed significantly to the advancement of the chemical and physical sciences during the first half of the nineteenth century. As an original investigator he determined, in collaboration with William Allen, the composition of carbon dioxide, and the density of ammonia, and elucidated the chemical phenomena of respiration in man. animals, and plants. The success of these researches was largely due to the use of ingenious apparatus of his own invention and design. In the field of experimental physics, he investigated several aspects of the recently discovered Voltaic electricity: his 'Voltaic coil', consisting of only two plates, but of very large dimensions, was particularly suited for investigating electromagnetic phenomena and was So used in Davy's researches. Pepys was one of the co-founders of the Mineralogical and Geological Societies, and was elected a Fellow of the Royal Society in 1808. As a prominent member of both the Royal and London Institutions, he held honorary office as Manager and Vice-President, contributing materially to the direction of the affairs of these bodies. Pepys was a friend of Humphry Davy and was acquainted with nearly all the leading scientists and medical men of the day. At the same time, he superintended a notable manufacture of Surgical instruments in the City, and promoted by his active directorship the affairs of two public companies, both pioneers in their technological fields, namely the Imperial Continental Gas Association, which was active in introducing the new gas illumination to cities and towns across Europe, and the General Steam Navigation Company, which first maintained a regular passenger and cargo service to Continental ports by the exclusive use of steam-propelled vessels. Pepys' advice in scientific and technical matters was widely sought and freely given; he retained his mental powers to the end of his long life, fulfilling his professional commitments until a few days before his death.