Who is Michelet from The Poetics of Space and what is their importance?

Michelet is quoted in Bachelard's work for calling the bird a worker without tools. Bachelard compares Robinet's idea of the snail rolling over and over to form its shell internally to Michelet's bird that turns round and round to form a nest externally with its round breast. Bachelard argues that dropping a word "almost" from Michelet's comment "a bird is almost completely spherical" makes another claim of a "round being" that can support Jaspers' principle.