to which the verb belongs.  Thus, for verbs of the first conjugation, it is a; as, from arare, to plough, arabilis, arable, tillable.  For the second conjugation, it is i; as, from doc=ere, to teach, docibilis, or docilis, docible or docile, teachable.  For the third conjugation, it is i; as, from vend=ere, to sell, vendibilis, vendible, salable.  And, for the fourth conjugation, it is i; as, from sepelire, to bury, sepelib~ilis, sep’elible,[125] buriable.  But from solvo and volvo, of the third conjugation, we have ubilis, uble; as, solubilis, sol’uble, solvible or solvable; volubilis, vol’uble, rollable.  Hence the English words, rev’oluble, res’oluble, irres’oluble, dis’soluble, indis’soluble, and insol’uble.  Thus the Latin verbals in bilis, are a sufficient guide to the orthography of all such words as are traceable to them; but the mere English scholar cannot avail himself of this aid; and of this sort of words we have a much greater number than were ever known in Latin.  A few we have borrowed from the French:  as, tenable, capable, preferable, convertible; and these we write as they are written in French.  But the difficulty lies chiefly in those which are of English growth.  For some of them are formed according to the model of the Latin verbals in ibilis; as forcible, coercible, reducible, discernible; and others are made by simply adding the suffix able; as traceable, pronounceable, manageable, advisable, returnable.  The last are purely English; and yet they correspond in form with such as come from Latin verbals in abilis.

OBS. 21.—­From these different modes of formation, with the choice of different roots, we have sometimes two or three words, differing in orthography and pronunciation, but conveying the same meaning; as, divis’ible and divi’dable, des’picable and despi’sable, ref’erable and refer’rible, mis’cible and mix’able, dis’soluble, dissol’vible, and dissol’vable.  Hence, too, we have some words which seem to the mere English scholar to be spelled in a very contradictory manner, though each, perhaps, obeys the law of its own derivation; as, peaceable and forcible, impierceable and coercible, marriageable and corrigible, damageable and eligible, changeable and tangible, chargeable and frangible, fencible and defensible, pref’erable and referrible, conversable and reversible, defendable and descendible, amendable and extendible, bendable and vendible, dividable and corrodible, returnable and discernible, indispensable and responsible, advisable and fusible, respectable and compatible, delectable and collectible, taxable and flexible.