At what rate these materials would be distributed and
     precipitated in regular strata, it is impossible to
     determine.—­AGASSIZ.

[Sidenote:  Adjective what in exclamations.]

152.  In exclamatory expressions, what (or what a) has a force somewhat like a descriptive adjective.  It is neither relative nor interrogative, but might be called an EXCLAMATORY ADJECTIVE; as,—­

     Oh, what a revolution! and what a heart must I have, to
     contemplate without emotion that elevation and that fall!—­BURKE.

     What a piece of work is man!—­SHAKESPEARE.

     And yet, alas, the making of it right, what a business for long
     time to come!—­CARLYLE

     Through what hardships it may attain to bear a sweet
     fruit!—­THOREAU.

Exercise.—­Find ten sentences containing pronominal adjectives.

INFLECTIONS OF ADJECTIVES.

153 .Adjectives have two inflections,—­number and comparison.

NUMBER.—­This, That.

[Sidenote:  History of this—­these and that—­those.]

154.  The only adjectives having a plural form are this and that (plural these, those).

This is the old demonstrative; that being borrowed from the forms of the definite article, which was fully inflected in Old English.  The article that was used with neuter nouns.

In Middle English the plural of this was this or thise, which changed its spelling to the modern form these.

[Sidenote:  Those borrowed from this.]

But this had also another plural, thas (modern those).  The old plural of that was tha (Middle English tho or thow):  consequently tho (plural of that) and those (plural of this) became confused, and it was forgotten that those was really the plural of this; and in Modern English we speak of these as the plural of this, and those as the plural of that.

COMPARISON.

155.  Comparison is an inflection not possessed by nouns and pronouns:  it belongs to adjectives and adverbs.

[Sidenote:  Meaning of comparison.]

When we place two objects side by side, we notice some differences between them as to size, weight, color, etc.  Thus, it is said that a cow is larger than a sheep, gold is heavier than iron, a sapphire is bluer than the sky.  All these have certain qualities; and when we compare the objects, we do so by means of their qualities,—­cow and sheep by the quality of largeness, or size; gold and iron by the quality of heaviness, or weight, etc.,—­but not the same degree, or amount, of the quality.