Daumas refers to 'I. Grgoire Blois' as working at the end of the seventeenth Century. The microscope could have been produced by him after moving to Paris, or by a relative. This design of simple micriscope was first produced in 1678 by the Dutch physicist, Christiaan Huygens (1629-1695). The inspiration goes back a few years to Antoni Leeuwenhoek (1632-1723), who made for himself simple bead microscopes from 1670. The Huygens model was made and sold commercially in Paris by Michael Butterfield, who issued an advertisement in 1679 with the title L'usage du microscope fait avec une seule et tres-petit boulle de verre.