natural history draughtsman and clerk, was born in Åbo, Sweden (now Turko, Finland), where his father, also Herman Diedrich, held the chair of medicine at Åbo University. Trained in medicine at his father’s university from 1748 to 1753, he initially practised as a surgeon in Stockholm, then, curiously, became a watchmaker in London for eleven years until employed as personal clerk to the Swedish naturalist Daniel Solander at the British Museum. On Solander’s recommendation Spring was enlisted by Joseph Banks as his personal secretary on Captain James Cook’s first voyage to the Pacific. On board the Endeavour he worked as clerk and amanuensis to both Banks and Solander, transcribing notes, making annotations and, inevitably, repairing the ship’s instruments when necessary. The two artists employed for the voyage were Sydney Parkinson and Alexander Buchan , for it had been Banks’s intention that while Parkinson drew the natural history specimens he and Solander collected, Buchan would depict views of the landscapes they saw. His hopes were dashed when Buchan died four days after the Endeavour reached Tahiti. The additional burden of topographical work then fell to Parkinson, but because Spring was a competent draughtsman he was able to relieve him.
According to Banks, Spring was 'a grave thinking man’ whose description of a 'most strange bird’ encountered in New Zealand must be accurate as he was 'not at all given to telling wonderful stories’. Most of his drawings, all in pencil, are of coastal views and fishes; a few of the natural history specimens have watercolour washes. There are some neat, careful and rather pedestrian pencil landscape sketches of some of the places where the Endeavour called, and equally precise visual documentation of native costumes, artefacts and dwellings. In particular, Joppien and Smith draw attention to 'his scale drawings of a large Maori canoe and his fine, painstaking series of drawings of the carvings on Maori canoes’, one of the subjects 'too large to collect and bring home’ for which his clear linearity and meticulous detailing were especially valuable.
Spring’s sketches, together with those by Parkinson and Buchan, are held in the British Library. Most are unsigned and attribution is often difficult. Indeed, it was not until about 1960 that Averil Lysaght and Alwyne Wheeler first distinguished Spring’s drawings from those by Parkinson with which they had previously been confused. Only some pencil sketches of fish and crabs relate to Australia.
On the way home to England Cook put in at Batavia Bay on the island of Java (Indonesia). There 'Batavia fever’ (dysentery and malaria) struck, which quickly began to decimate the crew. Almost becalmed, the ship made its way slowly back through the Sunda Straits hoping for the trade wind. On 24 January 1771 Spring died at sea, followed by Parkinson two days later.