(2006-11-12) Clausius' Virial of Force (1870)
A classical quantity homogeneous with an energy.
The name virial was coined in 1870
by Rudolf Clausius (1822-1888) from the genitive viris
of the Latin word vis (force, power or energy).
In the classical study of a system of N point-masses,
Clausius' original virial of force,
is obtained by summing up, for each point-mass, the dot
product of its position by the force it's subjected to:
Fi . ri
i = 1
In the absence of external forces, the sum
so the above doesn't depend on the arbitrary choice of an origin for spatial positions.