Example: add light speed
In this example, light speed is added.
Click Add data>Constant, at the bottom of the table, give "Light speed"
as constant name, "c" as symbole, 299,7924 as value, "Km/s" as unit, and a related
web site URL. Then click "Add this>" button. The this constant is shown in the
table, and your tracked constant list. (see figuire 1)
Figure 1. Add light speed constant