LSE4330807 The entrance into the classroom and the lecon, illustrations for the table of 4, by Bertall (Charles d\'Arnoux de Limoges Saint Saens, 1820-1882), for the manual ??????The fun calculation: the table of Pythagore??????by Trim, Hachette, Paris, second half of the 19th century. Leonard de Selva collection. by Bertall, Charles Albert d\'Arnoux (1820-82); Private Collection; (add.info.: The entrance into the classroom and the lecon, illustrations for the table of 4, by Bertall (Charles d\'Arnoux de Limoges Saint Saens, 1820-1882), for the manual ??????The fun calculation: the table of Pythagore??????by Trim, Hachette, Paris, second half of the 19th century. Leonard de Selva collection.); Photo by Leonard de Selva.