Hence other and whether (to which may be added either and neither) are pronouns with the comparative form.
Other has the additional peculiarity of possessing the plural form others. Hence, like self, it is, in the strictest sense, a substantival pronoun.
CHAPTER IX.
ON CERTAIN FORMS IN -ER.
[§ 237]. Preparatory to the consideration of the degrees of comparison, it is necessary to make some remarks upon a certain class of words, which, with considerable differences of signification, all agree in one fact, viz., all terminate in -er, or t-er.
1. Certain pronouns, as ei-th-er, n-ei-th-er, whe-th-er, or o-th-er.
2. Certain prepositions and adverbs, as ov-er, und-er, af-t-er.
3. Certain adjectives, with the form of the comparative, but the power of the positive degree; as upp-er, und-er, inn-er, out-er, hind-er.