Izak (also Isaac, Izaak) Petrus van Heerden Meiring, a pharmacist at Worcester, was the son of Jacobus (Koos) Wouter Henry Meiring, the first mayor of Worcester, and his wife Aletta M.E. van Heerden. He attended school in Worcester and at the age of 17 moved to Simon's Town where he trained as an apothecary with Mr A.H. Bull. He was registered to practice as a chemist and druggist in the Cape Colony on 17 April 1885. Returning to Worcester in 1886 he established the firm Bull & Meiring and opened the Railway Dispensary. By 1903 the firm had changed to Meiring & Quenet. On 27 August 1888 Izaak married Johanna Maria ("Mini") Greeff, with whom he had four children.
Meiring made regular meteorological observations at Worcester for the Meteorological Commission of the Cape of Good Hope from 1893, and a summary of his data was published annually in the commission's Report. From 1897, when the commission first categorised its meteorological stations as second order or climatological (third order), Meiring was in charge of a second order station. Two years later the secretary of the commission, Charles M. Stewart*, mentioned him in his annual report as displaying great enthusiasm for the work. Meiring continued his observations to the end of 1905, after which the station was closed.
His interest in zoology found expression in the selective collection of spiders for the South African Museum in Cape Town. In 1893 and 1897 he presented several perfect nests of a large trapdoor spider (Stasimopus sp.). These were followed by donations of three spiders in 1898, and several more from Worcester and Montagu in 1900. He was also a keen mountaineer and was instrumental in the founding of the Worcester Mountain Club in June 1893 - the first of its kind in South Africa.
Meiring published a single pharmacological paper, "On some experiments with the active principle of Mesembrianthemum tortuosum, L.", in the Transactions of the South African Philosophical Society (1895-1897, Vol. 9, pp. 48-50). It was one of the very few early papers on the chemistry of South African plants. He became a member of the society in 1897, and continued his membership until after it became the Royal Society of South Africa in 1908.
While the firm Meiring and Quenet continued to function until at least 1908 and Meiring was still registered as a chemist and druggist in 1915, he had years earlier decided on a new career. In 1899 he passed the examination for the Survey Certificate of the University of the Cape of Good Hope and the next year qualified as a land surveyor. From 1908 to 1916 Izak Meiring was listed in the General directory of South Africa as a surveyor residing in Worcester. He was also an amateur astronomer with his own telescope, became a country member of the Cape Astronomical Association, and at its meeting in September 1916 explained an equatorial mounting for stellar photography. He died the next year.