Microscope Slides Cut from Sheet, Coverslips from a Blown Bubble

A microscope slide is a strip of plain glass about 75 × 25 mm and 1 mm thick with smoothed edges; a coverslip is a much thinner square that presses the specimen flat. Cut the slides from thin sheet and grind the edges; for coverslips, blow a thin bubble on a glass tube and cut flat pieces from it. The picture: a tray of early 20th-century prepared slides under coverslips, museum of the Institut Pasteur de Lille.