This diagram engraving and accompanying chapter X entitled "To find out the real Size of Objects Seen by Microscopes" gives direction for how objects under magnification can be measured. The circle labeled ABCD represents a grain of sand. Animalcule number one reads "Twelve times less than the diameter BC," exemplifying how the shaded circle next to animalcule number one is one twelfth the size of the grain of sand. Number two reads "Four times less than the diameter of No. 1," with the accompanying shaded circle being sixty four times smaller than animalcule number one. The third animalcule reads "Ten times less than the diameter of No. 2," with a mathematical equation on pp. 43-44 illustrating how miniscule this animalcule is compared to the grain of sand.

This plate comes from The Microscope Made Easy by Henry Baker (1698-1774), a book that popularized the microscope in the 18th century. The first section describes simple and compound microscopes along with how to prepare specimens and calculate their size. The second section introduces the reader to microscopy and the laboratory manual. Also includes "Animalcules," or microscopic animals, and anatomical discoveries made with the microscope.