Mary Ball (1812-1892) discovered the underwater stridulation of the Notonectidæ
Mary, Countess of Rosse (1813-1885) was a pioneer in photography and also an accomplished amateur blacksmith
Mary Ward (1827-1869) was a popular science writer (how to use your microscope and telescope) who was unfortunately also the first person to be killed in a motor vehicle accident (probably), and the great-grandmother of Lalla Ward who played Romana II in Doctor Who.
Agnes Clerke (1842-1907), originally from Skibbereen, wrote a number of works on astronomy and cosmology including her Popular History of Astronomy during the Nineteenth Century for which today’s historians of science are still grateful
Lady Margaret Huggins (1848-1915), the daughter of a Dublin solicitor, became a pioneer of astronomical spectroscopy in partnership with her husband, Sir William Huggins (1824-1910) at their home in Tulse Hill
Matilda Knowles (1864-1933), researcher of lichens
Jane Scharff, née Stephens (1879-?) researcher of sponges, forced to leave scientific research when she married her boss
Mabel C Wright (née MacDowell), early 20th century geologist and naturalist, who helped pioneer the use of sphagnum moss as an antiseptic dressing
Phyllis Ryan (mid-20th century), professional chemist who interestingly kept her own name despite being married to a rather conservative politician
Máire Brück (1925-2008), astronomer who helped me with research into some of these.
During research in the Natural History Museum in South Kensington I was thrilled to find and read correspondence from Marie Stopes, though rather boringly about botany rather than contraception or eugenics.