The problem of the curves is solved by their reduction to a problem of straight lines; and the locus of any point is determined by its distance from two given straight lines - the axes of co-ordinates.
Also the auxiliarly circle is the locus of the feet of the perpendiculars from the foci on any tangent.
The manor, then called Bellus Locus or Beaulieu on account of its beautiful situation, was afterwards granted to the Mortimers, in whose family it continued until it was merged in the crown on the accession of Edward IV.
The lemniscate of Bernoulli may be defined as the locus of a point which moves so that the product of its distances from two fixed points is constant and is equal to the square of half the distance between these points.
But a little before Tertullian, Irenaeus, though he does not use the word ordo, anticipates in some measure Tertullian's abstract term, for he recognizes a magisterii locus, " a place of magistracy " or " presidency " in the church.