Henry James Slack

Henry James Slack was an English journalist, editor, and science writer born on October 23, 1818, and he died on June 16, 1896. An obituary published by Cambridge University Press describes him as one of the pioneers who promoted microscopical investigation in biology, and notes that he was educated at Dr. Evans' school in North End, Hampstead.

He began his working life in a wool-broker's office in London, became a partner, and then left the trade in 1846 because it did not suit his literary and scientific interests. He later studied law and was called to the Bar, though he never practiced. By the late 1840s and early 1850s he had moved into journalism, writing for the North Devon Journal and becoming proprietor and editor of the Atlas newspaper; he also served for a time as editor of the Westminster Quarterly.

Slack is best remembered for popular science writing, especially work connected with microscopy and natural history. Contemporary accounts credit him with helping to bring scientific observation to a wider public, and he is especially associated with lively writing about microscopic life. The portrait image available on his Wikipedia page appears to be an illustration rather than a true photographic portrait, so it may not be ideal, but it is the clearest author-related image I could confirm from the page.