Dictionary of National Biography, 1885-1900/Slack, Henry James
SLACK, HENRY JAMES (1818–1896), author, the son of Joseph Slack, a prosperous cloth merchant, was born in London on 23 Oct. 1818, and educated at North End, Hampstead. He exchanged a business life for journalism in 1846, and worked upon the ‘North Devon Journal’ and other provincial papers until, in 1852, he became proprietor and editor of the ‘Atlas.’ He also wrote much for the ‘Weekly Times,’ under the signature ‘Little John.’ From 1862 he edited the ‘Intellectual Observer,’ a development of a journal called ‘Recreative Science,’ founded in 1859. From 1868 to 1871 this was continued as ‘The Student.’ Meanwhile, in 1850, Slack published ‘The Ministry of the Beautiful’ (London, 8vo), a dialogue upon æsthetic subjects, and in 1860 an optimistic treatise upon ‘The Philosophy of Progress in Human Affairs.’ The ideas which he advocated through life both by precept and example were those of advanced liberalism. Such causes as that of anti-slavery, the abolition of the paper duties, and the higher education of women had in him a strenuous ally; he was a Cobdenite, a forward member of the national education league, and a warm friend of Kossuth and Mazzini. When specially moved, as in his defence of Orsini at Exeter Hall in 1856, Slack was an eloquent speaker. But the propaganda with which he was most closely identified were those of the Sunday League. He was president of the league in 1879, and inaugurated the popular lectures for Sunday evenings. He was no less zealous in the cause of the Sunday opening of museums and picture-galleries, to promote which the Sunday Society was formed in 1875.
In his leisure hours Slack was an ardent microscopist, and he was successively secretary and, in 1878, president of the Royal Microscopical Society. At odd moments during 1860 he composed ‘The Marvels of Pond Life,’ an attractive and essentially popular introduction to microscopical study (London, 1861, 8vo; 3rd edit. illustrated, 1878). Most of the ponds to which he refers have now been obliterated by the builder. Slack was a regular contributor to ‘Knowledge,’ and forty-six papers are ascribed to his name in the ‘Royal Society's Scientific Catalogue’ (selected from the ‘Popular Science Monthly,’ the ‘Meteorological Journal,’ and similar periodicals). In religious problems he was chiefly influenced by the unitarian William Johnson Fox [q. v.], whose works he edited in a ‘Memorial Edition’ (London, 12 vols. 8vo, 1865–8), in collaboration with William Ballantyne Hodgson [q. v.] He died at his house, Forest Row, Sussex, on 16 June 1896. His wife, Charlotte Mary Walters, whom he married in 1840, survived him.[Nature, 13 Aug. 1896; Daily News, 27 June 1896 (by Mr. G. J. Holyoake); private information.]