2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/9954Our knowledge of galactic chemical evolution is currently limited to observations of Milky Way stars and H II regions of nearby galaxies. Damped Lyman~$α$ systems offer a new approach for tracking the evolution of normal galaxies from early epochs to the present day. Here we report the first measurements of nitrogen abundances in galaxies with less than 1/100 of solar metallicity, a range unexplored by previous observations.7 pages, 3 figures. Uuencoded compressed PS file. Also available at http://www.ast.cam.ac.uk/preprint/PrePrint.htmlAstrophysicstext