Meynardus (or Meynhardus, Mynardus, Mynhardus) Ruysch was the son of Francis W.M. Ruysch and his wife Clara Leenbouwer. In 1815 he applied for permission to practise as a land surveyor in the Cape Colony. He was listed in the African court calendar from 1818 as living at 1 Keerom Street, and from 1820 as a sworn land surveyor. His work included survey maps of properties in Wynberg (1818, 1841, 1846), Port Elizabeth (1831), Rondebosch (1833), Worcester (1836), Cape Town (1837, 1838), Sea Point (1851), Beaufort West (1859-1869), and near Saldanha Bay (1861). He was declared insolvent in 1817, and again in 1832. On 12 August 1816 he married Catharina M. Heyneman in Cape Town and they had several children.
In December 1822 Reverend F. Fallows*, His Majesty's Astronomer at the Cape, moved from a house in Kloof Street to Wandel Street and asked Ruysch to determine the difference in latitude between his old and new temporary observatories. Ruysch measured a baseline on upper Orange Street, corrected its length for slope, and by triangulation fixed the positions of Fallows's old and new residences, the houses of Mr van Breda and Mr Moller. The positions of the two observing sites were linked to the houses by measuring a bearing and distance. Fallows would have provided an accurate azimuth (direction of true north). Ruysch drew a plan of his work and calculated the difference in latitude between the two observing sites to be 12.8 seconds of arc.
In March 1843 Ruysch and John Skirrow* assisted C.P. Smyth* of the Royal Observatory, Cape of Good Hope, with some observations of the Great Comet of 1843. They stayed at the observatory for a few days for that purpose.
Ruysch is credited with introducing a new system of calculation and plotting for farm surveys, by means of rectangular coordinates. The method was later systematized and perfected by Leopold Marquard* in 1848 (Bull, 1981, p. 19).
In June 1858 Ruysch was appointed by the governor as one of the commissioners (the others included T. Maclear*, G.F. Childe* and L. Marquard*) who were to ascertain and fix the size of the unit of land measure used in the Colony - a local version of the Rhynland foot. The only standards available for this purpose were two measuring rods of six Rhynland feet each that had been used by L.M. Thibault* and were later bought by Ruysch. By comparing these rods to British standards the commission found that the land unit was equivalent to 1.033 British Imperial feet (314.85mm) and renamed it the Cape foot. It remained in use as the South African unit of land measure until replaced by the metre in the nineteen-sixties.
In November 1838 Ruysche subscribed one pound sterling for the erection of a monument on the site of Sir John Hershel's telescope at the Cape. He was married a second time, on 6 November 1847 in Cape Town, to Anna M.E. Meyer.