The plumb bob; nothing more than a simple pointed weight, suspended from one end of a string, and used to determine a line perpendicular to a point. The realization of this phenomenon was as important to the development of civilization as the number 0.

Siena Heights University
1247 E. Siena Heights Dr.
Adrian, MI 49221
tel. 517-264-7865
fax. 517-264-7739
email. jwitters@sienaheights.edu