Henry Siebe was the second Son of Augustus Siebe . He was born in 1830. He spent much of his early life in France and came to England around 1860 He was fluent in French and had a very good understanding of the scientific work of the Company. In 1868 when his father retired from the manufacturing side of the company Henry formed a partnership with William Gorman and in 1870 the new company of Siebe & Gorman was formed.
Henry Siebe is best known for the book he published titled.

The Conquest of the Sea.
The preface interestingly suggests that the Science of Diving had already at that point in time, the 1870s reached a point of perfection. The Conquest of the Sea was the first book written which explained about the advances and development of Manís pioneering exploration of the sea bed. Many books had already been written about the sea without reference to divers and their work so this was a landmark publication. The book was not written merely as an account of the history of diving rather a series of examples of some of the achievements as there were so many by that time it would take volumes to describe them all.

The Conquest of the Sea is not merely a catalogue of events and achievements but also a philosophical view of the possibilities and opportunities awaiting mansí exploration of the sea.

Henry Siebe died at the age of 55 in 1885.