Equal Beating, what does it mean?

[Richard Moody]

I would like to determine what "Equal Beating" means when it occurs in the title,
"Equal Beating ________ Temperament".   



I have a "finding" I am trying to verify.  

Under what circumstances will the Third  C4--E4  equal the beat rate of the Sixth
C4--A4  and all the rest? (others)---ric