The Nosepiece is the part that holds the microscope objective lenses. A compound microscope usually has 10x eyepieces. The objective lenses that are held by the revolving nosepiece are usually 4x, 10x, 20x, 40x, 60x, 80x and 100x. That gives a magnification range of 40x to 1000x 10x4 and 10x100.
http://www.microscope-microscope.org/basic/microscope-parts.htm 
