*logarithmical*

{ } a. [ Cf. F. logarithmique. ] 1. Of or pertaining to logarithms; consisting of logarithms. [ 1913 Webster ]

2. Using logarithms; as, logarithmic graph paper; a logarithmic scale. [ PJC ]

3. Having a logarithm in one or more of the unknowns; -- of an equation. [ PJC ]

Logarithmic curve (Math.), a curve which, referred to a system of rectangular coordinate axes, is such that the ordinate of any point will be the logarithm of its abscissa. --
Logarithmic spiral, a spiral curve such that radii drawn from its pole or eye at equal angles with each other are in continual proportion. See Spiral. [ 1913 Webster ]