Words that import a relation, must be distinguished from those that do not. Substantives commonly imply no relation, such as _animal_, _man_, _tree_, _river_. Adjectives, verbs, and adverbs, imply a relation. The adjective _good_ must be connected with some substantive, some being possessed of that quality. The verb _write_ must be applied to some person who writes; and the adverbs _moderately_, _diligently_, have plainly a reference to some action which they modify. When in language a relative term is introduced, all that is necessary to complete the expression, is, to ascertain that thing to which the term relates. For answering this purpose, I observe in Greek and Latin two different methods. Adjectives are declined as well as substantives; and declension serves to ascertain the connection that is betwixt them. If the word that expresses the subject be, for example, in the nominative case, so also must the word be that expresses its quality. Example, _vir bonus_. Again, verbs are related, on the one hand, to the agent; and, on the other, to the subject upon which the action is exerted. A contrivance similar to that now mentioned, serves to express this double relation. The nominative case is appropriated to the agent, the accusative to the passive subject; and the verb is put in the first second or third person, to correspond the more intimately with both. Examples: _Ego amo Tulliam_; _tu amas Semproniam_; _Brutus amat Portiam_. The other method is by juxtaposition, which is necessary with respect to words only that are not declined, adverbs for example, articles, prepositions, and conjunctions. In the English language there are few declensions; and therefore juxtaposition is our chief resource. Adjectives accompany their substantives[89]; an adverb accompanies the word it qualifies; and the verb occupies the middle place betwixt the active and passive subjects to which it relates. It must be obvious, that those terms which have nothing relative in their signification, cannot be connected in so easy a manner. When two substantives happen to be connected, as cause and effect, as principal and accessory, or in any other manner, such connection cannot be expressed by contiguity solely; for words must often in a period be placed together which are not thus related. The relation betwixt substantives, therefore, cannot otherwise be expressed than by particles denoting the relation. Latin indeed and Greek, by their declensions, go a certain length to express such relations, without the aid of particles. The relation of property, for example, betwixt Cæsar and his horse is, expressed by putting the latter in the nominative case, the former in the genitive; _equus Cæsaris_. The like in English, _Cæsar’s horse_. But in other instances, declensions not being used in the English language, relations of this kind are commonly expressed by prepositions.