Giovanni Virginio Schiaparelli (1835-1910) : a two-faced Janus

When in the night of the 23 of August 1877, Schiaparelli turned his new 218 mm refractor Merz to Mars in a favourable opposition he didn't presume to dedicate a regular series of observations to the red planet. Schiaparelli wanted test if the Merz, excellent in the observation of double stars, had good optical qualities for observing planet surfaces. But that short raid on the red planet changed his scientific life. From 1877 until his death Schiaparelli studied Mars. In my paper I'll analyse the seven Schiaparelli's memoirs on Mars published on the Atti dell'Accademia del Lincei from the 1878 to 1910. Then I'll analyse some of the articles he wrote on popular magazines. I'll show that while in the Lincei memoirs he is rigorous, in his divulgation papers he dares hypothesis on the intelligent life on Mars which were not scientifically grounded. And I'll try to answer to the question of this contradiction.