In modern English, polysyllabic verbs ending in -ate are regularly stressed on the third-to-last syllable. (There are some (possible) exceptions, such as incarnate, impregnate, and elongate.)
But it seems that certain speakers in the past followed a different rule, whereby the stress fell on the second-to-last syllable when it was "closed" (ended in a consonant) in Latin. A well-known example of an -ate verb that used to have this stress pattern is contemplate; the Oxford English Dictionary entry for this word summarizes the situation as follows:
In a few rare cases (Shakespeare, Hudibras) stressed ˈcontemplate in 16–17th cent.; also by Kenrick 1773, Webster 1828, among writers on pronunciation. Byron, Shelley, and Tennyson have both modes, but the orthoepists generally have conˈtemplate down to third quarter of 19th cent.; since that time ˈcontemplate has more and more prevailed, and conˈtemplate begins to have a flavour of age. This is the common tendency with all verbs in -ate. Of these, the antepenult stress is historical in all words in which the penult represents a short Latin syllable, as acˈcelerate, ˈanimate, ˈfascinate, ˈmachinate, ˈmilitate, or one prosodically short or long, as in ˈcelebrate, ˈconsecrate, ˈemigrate; regularly also when the penult has a vowel long in Latin, as ˈalienate, ˈaspirate, conˈcatenate, ˈdenudate, eˈlaborate, ˈindurate, ˈpersonate, ˈruinate (Latin aliēno, aspīro, etc.). But where the penult has two or three consonants giving positional length, the stress has historically been on the penult, and its shift to the antepenult is recent or still in progress, as in acervate, adumbrate, alternate, compensate, concentrate, condensate, confiscate, conquassate, constellate, demonstrate, decussate, desiccate, enervate, exacerbate, exculpate, illustrate, inculcate, objurgate, etc., all familiar with penult stress to middle-aged men. The influence of the noun of action in -ation is a factor in the change; thus the analogy of ˌconseˈcration, ˈconsecrate, etc., suggests ˌdemonˈstration, ˈdemonstrate. But there being no remonstration in use, reˈmonstrate, supported by reˈmonstrance, keeps the earlier stress.
(bolding added for emphasis)
Based on this information, I thought that the rare verb altercate must have used to have a pronunciation with stress on the second-to-last syllable. But I've had some trouble finding material that supports my guess.
The Oxford English Dictionary gives the present-day pronunciations as "Brit. /ˈɔːltəkeɪt/, /ˈɒltəkeɪt/, U.S. /ˈɔltərˌkeɪt/, /ˈɑltərˌkeɪt/" and has a note saying "N.E.D. (1884) also gives the pronunciation as (æ·ltəɹkeit) /ˈæltəkeɪt/" (which is interesting, but doesn't answer my question).
One of the earlier OED citations, from F. Quarles Divine Fancies i. xl (the OED gives the date as 1632), uses the word in verse in a context where it seems it would have to scan as stressed-unstressed-stressed:
Whenas my Body and my Soule shall plight
Inviolable faith, and never fight
Nor wrangle more, nor altercate, again,
About that strife-begetting question, Sin !
(The Complete Works in Prose and Verse of Francis Quarles, by Alexander B. Grosart, 1880)
Annoyingly, the verb doesn't seem to have an entry in John Walker's Critical Pronunciation Dictionary of 1791, although Walker evidently was familar with it since he uses it in the definitions of "to chop" and "to stickle" (though the "stickle" definition doesn't seem to have originated with Walker, as it can also be found in Sheridan's dictionary and Johnson's dictionary).
Does anyone know of any evidence for stress ever falling on the second syllable of altercate in the past? I'm thinking the most likely place such information would appear is in old dictionaries or poems. The OED's earliest citation for the verb is from 1530.