OBS. 7.—­In the compound tenses, there is never any variation of ending for the different persons and numbers, except in the first auxiliary:  as, “Thou wilt have finished it;” not, “Thou wilt hast finishedst it;” for this is nonsense.  And even for the former, it is better to say, in the familiar style, “Thou will have finished it;” for it is characteristic of many of the auxiliaries, that, unlike other verbs, they are not varied by s or eth, in the third person singular, and never by st or est, in the second person singular, except in the solemn style.  Thus all the auxiliaries of the potential mood, as well as shall and will of the indicative, are without inflection in the third person singular, though will, as a principal verb, makes wills or willeth, as well as willest, in the indicative present.  Hence there appears a tendency in the language, to confine the inflection of its verbs to this tense only; and to the auxiliary have, hast, has, which is essentially present, though used with a participle to form the perfect. Do, dost, does, and am, art, is, whether used as auxiliaries or as principal verbs, are always of the indicative present.

OBS. 8.—­The word need,—­(though, as a principal verb and transitive, it is unquestionably both regular and complete,—­having all the requisite parts, need, needed, needing, needed,—­and being necessarily inflected in the indicative present, as, I need, thou needst or needest, he needs or needeth,—­) is so frequently used without inflection, when placed before an other verb to express a necessity of the being, action, or passion, that one may well question whether it has not become, under these circumstances, an auxiliary of the potential mood; and therefore proper to be used, like all the other auxiliaries of this mood, without change of termination.  I have not yet knowingly used it so myself, nor does it appear to have been classed with the auxiliaries, by any of our grammarians, except Webster.[258] I shall therefore not presume to say now, with positiveness, that it deserves this rank; (though I incline to think it does;) but rather quote such instances as have occurred to me in reading, and leave the student to take his choice, whether to condemn as bad English the uninflected examples, or to justify them in this manner.  “He that can swim, need not despair to fly.”—­Johnson’s Rasselas, p. 29.  “One therefore needs not expect to do it.”—­Kirkham’s Elocution, p. 155.  “In so doing I should only record some vain opinions of this age, which a future one need not know.”—­Rush, on the Voice, p. 345.  “That a boy needs not be kept at school.”—­LISDSEY:  in Kirkham’s Elocution, p. 164.  “No man need promise, unless he please.”—­Wayland’s Moral Science, p. 312.  “What better