The main idea that the 2007 article makes clear is that Welch considers Chiasmus to be a sufficient condition for an antique Jewish writing. This is important in terms of the logical claims that one can make. However, to me the 2007 article suggests that Welch effectively took this upon the authority of Gaertner during their discussions in Regensburg.
After becoming an academic researcher, Welch started to write about Chiasmus repeatedly, for all of antiquity, and in monographic form, so to speak. This website lists and links to most of the articles published in the context of FARMS, but gives only the names of the books. In the process he published an important bibliography of Chiasmus.
Why this mattered to Mormonism comes across not only in the 40 years later article, but is clearly exposed in an essay entitled What Does Chiasmus in the Book of Mormon prove? (1997) where Welch shows Alma 36 as a particularly successful example of Chiastic structure. Here, Welch argues:
If the absence of chiasmus would be inconsistent with its claim of Israelite origins, then the presence of chiasmus in the Book of Mormon is, at least to an equal extent, evidence corroborating that claim.But this only follows if one already buys into the sufficient condition argument. Most people would rather see it as a necessary condition, which is the weaker interpretation of the first part of the if-clause. Mainly this quote highlights again that to Welch following Gaertner, this was a sufficient criterion.
At the end of the article, Welch cites Thomas F. O'Dea, The Mormons (Chicago: University of Chicago Press, 1957), 26, as saying that
[The Book of Mormon] has not been universally considered as one of those books that must be read in order to have an opinion on it.[RCK: Partly this is the books fault, whose repetitive structure and convoluted prose make for an uninspiring and dull read. Who would want to read this book after having read the first few pages?]
Welch tried to drill down on the history of Chiastic knowledge in 1829 in a paper in 2003, which he updated in 2007. However, both of these suffer from issues:
- The Philadelphia publishing company of Littell ran an ad in the Wayne County Sentinel on April 6th, 1825, on page 3, for subscriptions of Horne's Introduction at $12, $16 at publication price. The ad clearly mentions Hebrew Poetry as well as the previous three editions.
- Princeton University had an earlier edition of Horne in their library than the one mentioned in your article, as we now know from the internet archive, albeit the one from 1828, which is of course very very late for influencing Joseph Smith Jr in any way.
- Finally, Welch did not discuss Philip Sarchi's 1824 work on Hebrew Poetry in the 2003 paper as a source of Chiastic information, but mentioned him in the context of Horne's bibliography in that paper.
External CriticismFor counter-arguments to the chiastic theory, see Sandra Tanner's argument and the longer enumeration of problems by Jared and Sandra Tanner here, especially the discussion of Chiastic structures in the Doctrines and Covenants and in the Pearl of Great Price. (Of course, in his 1997 article, Welch explicitly finds the D&C and PoGP examples unconvincing ... without giving much detail on them.)
Also the observation that some of the Chiastic structures in the Book of Mormon are actually due to rewording from the Scriptures, where the original text---often by St Paul---exhibits Chiastic structure, is interesting.
Finally, the Tanners mentioned a book on Hebrew poetry from the 18th century that did not discuss Chiasmus, but the substance of the matter. Thus the hunt for specific Chiastic books may be a red herring.
For more focused criticism of Welch's operation, the paper by Earl M. Wunderli in Dialogue: 38/4 [Winter 2005] pp.97-110 argues that the impressive Chiastic structure of Alma 36 is achieved through a loose application of the rules. The rebuttal by father-son team Boyd and Farrell Edwards (alas without the counter-reply by Wunderli) was published here. The John Kselman review "Ancient Chiasmus Studied" of the book Chiasmus in Antiquity that Welch had edited is truncated on the Dialogue website, having two pages where it should have four.