Henry James Slack

[5] Slack advocated liberal ideas: opposition to slavery, the abolition of the paper duties, and the higher education of women.

[6] A friend of the politicians Lajos Kossuth and Giuseppe Mazzini, Slack spoke for Felice Orsini at Exeter Hall in 1856.

[2] In 1850, Slack published The Ministry of the Beautiful (London), a dialogue on aesthetics, and in 1860 an upbeat treatise The Philosophy of Progress in Human Affairs.

He was a regular contributor to Knowledge, and 46 papers under his name in the Royal Society's Scientific Catalogue were selected from Popular Science Monthly, the Meteorological Journal, and similar periodicals.

[8] In 1868 he was introduced to William Michael Rossetti, as a "legal gentleman", leading to some opaque dealings with a role in literary history.

Slack lent to Rossetti some letters of Percy Bysshe Shelley, which had been part of a correspondence in his early life with Elizabeth Hitchener.

[9] What Slack told Thomas James Wise, who saw the letters through Rossetti, was that Hitchener had gone abroad, and married an Austrian officer.

[11] It is also unclear why they were deposited, given that Slack was not a lawyer; and he did not claim he owned them; he gave an indication of the owner as a lady living in Germany.