It is the first of what have been called the seven sciences, or liberal branches of knowledge; namely, grammar, logic, rhetoric, arithmetic, geometry, astronomy, and music.

_Secondly_, It is as skill, to the thing to be done; and as power, to the instruments it employs.

In these relations, grammar is an art; and as such, has long been defined, "_ars recte scribendi, recteque loquendi_" the art of writing and speaking correctly.

_Thirdly_, It is as navigation, to the ocean, which nautic skill alone enables men to traverse.
In this relation, theory and practice combine, and grammar becomes, like navigation, a practical science.

_Fourthly_, It is as a chart, to a coast which we would visit.