There are 9 titles associated with this firm.

Robertson, Mrs. Florence: or The Aspirant. A Novel, in three volumes. London: Whittaker, Treacher, and Arnot, 1829.
Edgeworth, Maria. Tales And Novels by Maria Edgeworth. In Eighteen Volumes. London: Joseph Booker, W. Simpkin and R. Marshall, John Murray II [Albemarle], Anthony King Newman and Co., George Smith, Alexander Elder and Co., E. Hodgson, Robert Baldwin and Charles Cradock, Frances Houlston and Son [Wellington], Whittaker, Treacher, and Arnot, J. Bain, R. Mackie, Renshaw and Rush, G. and J. Robinson [Liverpool], Thomas Tegg [73 Cheapside], John Templeman [1830-9], 1832.
The Parent's Poetical Anthology: Being a Selection of English Poems Primarily Designed to Assist in Forming the Taste and the Sentiments of Young Readers. Third edition with additions. London: W. Simpkin and R. Marshall, Longman, Rees, Orme, Brown, and Green, John Richardson [Royal Exchange], Robert Baldwin and Charles Cradock, Whittaker, Treacher, and Arnot, John, George, and Francis Rivington, John Souter [St. Paul's Churchyard], 1832.
Shelley, Mary Wollstonecraft, et al. The Winter's Wreath for MDCCCXXXII. London: Whittaker, Treacher, and Arnot, George Smith, 1832.
Child, Lydia Maria Francis. The Western Coronal; a Collection of Pieces, Written at Various Times. ... Second edition, revised and enlarged. By Mrs. Child. Glasgow: Thomas Oliver and George Boyd [High Street], Whittaker, Treacher, and Arnot, John Reid and Co., 1833.