In the second half of the 19th century, the concept of ‘scientific popularization,’ which referred primarily to the idea of communicating science to lay people, was used considerably in Brazil. Popularizers of sciences sought, through books, magazines, journals, conferences, and exhibitions, to communicate the knowledge of science to the general public, especially to the working class and children. The number of periodicals expanded, covering a wide variety of themes and publics. Imbued in these publications was the idea of science for all and the conviction that the cultivation of science was an instrument to obtain knowledge about new nations and to educate the population. Here we will highlight some Brazilian journals which, in the second half of the nineteenth century, were edited and/or written by popularizers, the so-called ‘intellectual mediators,’ who dedicated their pages to the popularization of Science. These include A semana. Jornal litterario, scientifico e noticioso (Rio de Janeiro, 1855); Academia popular. Semanário de Instrucção e Recreio para o Povo (Recife, 1863); Illustração Popular (Rio de Janeiro, 1876); Revista do Rio de Janeiro (Rio de Janeiro, 1876); O Vulgarisador. Jornal dos conhecimentos uteis (Rio de Janeiro, 1877); Sciencia para o povo. Serões instructivos (Rio de Janeiro, 1880); and Barão de Macahubas. Periodico scientifico, litterario e noticioso (Bahia, 1886)