χαλκός = Copper.
Deal = Landing-place of Cæsar.
A multitude of propositions involving singular terms fall into the same form, as in
The Pole star = The slowest-moving star.
Jupiter = The greatest of the planets.
The ringed planet = The planet having seven satellites.
The Queen of England = The Empress of India.
The number two = The even prime number.
In mathematical and scientific theories we often meet with simple identities capable of expression in the same form. Thus in mechanical science “The process for finding the resultant of forces = the process for finding the resultant of simultaneous velocities.” Theorems in geometry often give results in this form, as
Equilateral triangles = Equiangular triangles.
Circle = Finite plane curve of constant curvature.