The Virtual Microscope is an Open University (UK) Project. It is described on this site in the following terms:
"A prototype version of the virtual microscope to be used on the Open University course S276 in 2010 has been developed by KMi in collaboration with the departments of Earth and Environmental Sciences and LTS (Learning and Teaching Solutions).
In contrast to the fixed 'virtual instrument' format developed for previous generations of the course, the petrological microscope was designed as a set of intercommunicating modules. This might allow for more flexibile use as they were designed to be embedded within web-based courses and assessment activities."
Demonstrations that illustrate how the virtual microscope works are available from this site.