if ever, interchangeable.  To put one for the other, is therefore, in general, to put one meaning for an other:  “A daughter of a poor man”—­“The daughter of the poor man”—­“A daughter of the poor man”—­and, “The daughter of a poor man,” are four phrases which certainly have four different and distinct significations.  This difference between the two articles may be further illustrated by the following example:  “That Jesus was a prophet sent from God, is one proposition; that Jesus was the prophet, the Messiah, is an other; and, though he certainly was both a prophet and the prophet, yet the foundations of the proof of these propositions are separate and distinct.”—­Watson’s Apology, p. 105.

OBS. 4.—­Common nouns are, for the most part, names of large classes of objects; and, though what really constitutes the species must always be found entire in every individual, the several objects thus arranged under one general name or idea, are in most instances susceptible of such a numerical distribution as gives rise to an other form of the noun, expressive of plurality; as, horse, horses.  Proper nouns in their ordinary application, are, for the most part, names of particular individuals; and as there is no plurality to a particular idea, or to an individual person or thing as distinguished from all others, so there is in general none to this class of nouns; and no room for further restriction by articles.  But we sometimes divert such nouns from their usual signification, and consequently employ them with articles or in the plural form; as, “I endeavoured to retain it nakedly in my mind, without regarding whether I had it from an Aristotle or a Zoilus, a Newton or a Descartes.”—­Churchill’s Gram., Pref., p. 8.  “It is not enough to have Vitruviuses, we must also have Augustuses to employ them.”—­Bicknell’s Gram., Part ii, p. 61.

   “A Daniel come to judgment! yea, a Daniel!”
        —­SHAK. Shylock.

   “Great Homer, in th’ Achilles, whom he drew,
    Sets not that one sole Person in our View.”
        —­Brightland’s Gram., p. 183.

OBS. 5.—­The article an or a usually denotes one out of several or many; one of a sort of which there are more; any one of that name, no matter which.  Hence its effect upon a particular name, or proper noun, is directly the reverse of that which it has upon a common noun.  It varies and fixes the meaning of both; but while it restricts that of the latter, it enlarges that of the former.  It reduces the general idea of the common noun to any one individual of the class:  as, “A man;” that is, “One man, or any man.”  On the contrary, it extends the particular idea of the proper noun, and makes the word significant of a class, by supposing others