 The 7th edition was begun in 1827 and published from March 1830 to January 1842, although all volumes have title pages dated 1842.It was a new work, not a revision of earlier editions, although some articles from earlier editions and supplements are used.It was sold to subscribers in monthly "parts" of around 133 pages each, at 6 shilling per part, with 6 parts combined into 800 page volumes for 36 shillings.