In 1800 he commenced the Farmer's Magazine, and in the following year acquired the property of the Scots Magazine, a venerable repertory of literary, historical, and antiquarian matter; but it was not until the establishment of the Edinburgh Review, in October 1802, that Constable's name became a power in the publishing world.

He edited repertories of chemistry and physics, a pharmaceutical journal, and an encyclopaedia in eight volumes, of which he wrote about one third.

In the once well known "Memoirs of a Certain Island adjacent to the Kingdom of Utopia" (1725-6) and the no less infamous "Secret History of the Present Intrigues of the Court of Carimania" (1727) Mrs. Haywood found a fit repertory for daringly licentious gossip of the sort made fashionable reading by Mrs. Manley's "Atalantis."

A prime interest attaches to this work, because, unconsciously, the author has given us, in advance, his repertory of instruments and principles.