Quotation from: General Science

Written by: Bertha M. Clark

Hammers (Fig. 102), tack-lifters, scissors, forceps, are important
levers, and if you will notice how many different levers (fig. 103)
are used by all classes of men, you will understand how valuable a
machine this simple device is.

155. The Inclined Plane. A man wishes to load the 600-pound bowlder
on a wagon, and proceeds to do it by means of a plank, as in Figure
93. Such an arrangement is called an inclined plane.