This paper provides a first approach to the history of "Iberica," one of the most important popular science magazines published in Spain before the Civil War. Founded in 1914 by members of the Society of Jesus based at the Ebro Observatory, "Iberica" reached a weekly circulation of about 10,000 in the mid 1920s, and was instrumental in extending science education in Jesuit education facilities and in developing a "reactionary modernist" culture that embraced Catholicism and modernisation. By focusing on its coverage of radioactivity and the radium industry, the article aims to examine the magazine's popularising style and ideology, and to determine its role in the debates regarding the cultural value of science in the first decades of twentieth century Spain.