While he didn't invent the compound microscope, his own design was significantly improved from earlier versions. It featured:
* Two lenses: an objective lens near the specimen and an eyepiece lens for viewing. This allowed for higher magnification compared to single-lens microscopes.
* A mechanical stage: This allowed for precise movement of the specimen.
* Illumination: Hooke designed his own illumination system, using a mirror to direct sunlight onto the specimen.
His microscope was a remarkable achievement for its time, allowing him to make detailed observations of insects, plants, and other small objects. It was through this instrument that he famously discovered and named "cells" while studying a thin slice of cork.