Pierce Morton, of Kilnacrott, County Cavan, Ireland, was the son of Charles Carr Morton and his wife Charlotte, born Tatlow. He was a Cambridge mathematician who qualified as Master of Arts (MA). In 1925 he was appointed as professor of mathematics and natural philosophy, and as a Fellow of King's College, in Nova Scotia, Canada. However he left that province the next year. In 1830 he produced two publications. One was a paper, "On the focus of a conic section", in the Philosophical Transactions of the Royal Society (1830), in which he presented a new proof of the focus-directrix property of conic sections using Dandelin spheres. The other was a book, Geometry, plane, solid and spherical, in six books; to which is added, in an appendix, the theory of projection... (London, 1830, 272 pp). During at least 1840-1844 he was teaching in France, but returned to Britain before 1851.
On 1 November 1851 Morton was appointed to succeed G.R. Smalley* as third assistant at the Royal Observatory, Cape of Good Hope, under the direction of Thomas Maclear*. Assuming duty on 26 November, his work consisted of daily measurements of the parameters of the earth's magnetic field, namely magnetic declination, magnetic inclination, horizontal and vertical field strength, and total absolute field strength. A few months later, on 12 March 1852, the magnetic observatory burnt down and though a court of inquiry was set up, no definite cause of the fire was discovered. Though the building was a complete loss, the instruments were saved and Morton was able to continue the observations. However, Maclear began to employ him also in astronomical work. As a result magnetic intensity measurements were stopped in October 1857 and inclinations in March 1858, though declinations continued to be recorded. In the October 1857 issue of the Cape Monthly Magazine Morton published a short paper titled "Notes on the earthquake".
In 1839 Morton married Louisa Somerville, with whom he had four children. He died in office in April 1859. The day after his death his son, Pierce Edward Morton (1842-1861) assumed duty at the Royal Observatory as fourth assistant; however, he resigned in July 1860 and went to Canada, where he drowned the next year.