[1] Later he obtained the post of secretary to a commission for adjusting St. Domingo claims, and settled in a house adjoining Poets' Corner, Westminster.
[2] Martin published The Aurelian's Vade-mecum; containing an English Catalogue of Plant' affording nourishment to Butterflies, Hawkmoths, and Moths in the state of Caterpillar, Exeter, 1785, and Observations on Marine Vermes, Insects, &c., fasc.
[2] About 1796 Martin began "an enquiry into the circumstances of beggars in the metropolis", and joined the Society for Bettering the Condition and Increasing the Comforts of the Poor, of which he acted for a time as secretary.
[3][4] He proposed a plan for a systematic inquiry into the nature and extent of begging in London, and in 1800 obtained a grant of £1,000 from the treasury in two instalments.
His report, in the form of a Letter to Lord Pelham on the State of Mendicity in the Metropolis, was published in 1803, and reissued by the society in 1811.