Before revision: Making According to Luca de Samuele Cagnazzi's unpublished autobuiography La mia vita, the tonograph was made by Cagnazzi himself with his own hands ("colle mie mani") in 1841.
After revision: Making According to Luca de Samuele Cagnazzi's unpublished autobiography La mia vita, the tonograph was made by Cagnazzi himself with his own hands ("colle mie mani") in 1841.