Resumen de 50, 100 & 150 years ago.

• The article presents excerpts from previous articles about scientific issues. A quotation from physicists Murray Gell-Mann and E.P. Rosenbaum from 1957 discusses the classification of strange particles. A quotation from 1907 speculates on the possibility of vegetation on the planet Mars. A quotation from 1857 describes an air mask designed for firefighters.