a timepiece made to exhibit the differences between mean solar and apparent solar time. Knight. —
Normal equation. See under Normal. — Personal equation (Astron.), the difference between
an observed result and the true qualities or peculiarities in the observer; particularly the difference, in an
average of a large number of observation, between the instant when an observer notes a phenomenon,
as the transit of a star, and the assumed instant of its actual occurrence; or, relatively, the difference
between these instants as noted by two observers. It is usually only a fraction of a second; — sometimes
applied loosely to differences of judgment or method occasioned by temperamental qualities of individuals.
— Theory of equations (Math.), the branch of algebra that treats of the properties of a single algebraic
equation of any degree containing one unknown quantity.