A timely group test for open-access search:

JURN group test: Salem Mather “witch trials”
October 2014. Searching for free full-text scholarly articles, theses or book chapters in English, with discussion of Cotton Mather’s role in the famous Salem witch trials. Search used:   Salem Mather “witch trials”. Clicked through on possible results, and briefly evaluated.
DOAJ 0 Used ‘Article’ search. 0 from zero results.
Journal Click 0 2 ‘possibles’ from six results. But neither were counted, as they were in no way focussed on Mather.
JournalTOCS 0 0 from zero results.
Ingenta Connect 0 0 from zero results.
Journal Seek 0 0 from zero results.
Paperity 0 0 from zero results.
Mendeley 0 0 relevant results on first two pages of results. Searched ‘Articles’ only, then filtered for Open Access articles only.
OAlib 0 Looked at the first three pages of results.
CORE 1 Filtered search by English language. Looked at first three pages of results. The book Cotton Mather and Salem witchcraft was from 1868, and consisted of articles reprinted from the Boston Advertiser. The other result was only tangential, a single-page book review.
OpenAIRE 1 Filtered for both ‘English language’ items, and ‘Open Access’. Unable to retain “witch trails” as a phrase, forced to remove inverted commas.
Microsoft Academic 1 1 from two results.
Google Scholar 1 Examined first 60 results. Google Books links not counted. Several of the full-text links were “404 Not Found”. Best article was “Dutch New York and the Salem Witch Trials: Some New Evidence” with light discussion of Mather throughout, although he was not the focus of the article. Ranking high was an interesting article on the possibility of hallucinatory mycotoxins in Salem food, but this had only a fleeting naming of Mather.
OATD 2 2 from two results, both useful for an in-depth researcher. “Cotton Mathers’s Wonders of the Invisible World: An Authoritative Edition” was one, and a strong article “American identity at a crossroads: Cotton Mather’s Wonders of the Invisible World“.
NDLtd 2 2 from three results. The same two results as OATD (see above).
BASE 2 2 of five results. The same two results as OATD (see above). Searched ‘Verbatim’ on ‘Entire Document’, “Boosted” open access documents in results. Several results were ancient 1891 newspaper articles from the Deseret News.
Digital Commons Network 2 2 from seven results.
Google Search 2 Forced verbatim, and used a Web browser not signed in to Google. Examined first 50 results. One good modern result, and one possibly useful article from 1886.
OPENDoar 8 8 strong candidates. Examined first 50 results. Some duplicates and Archive.org clutter.
JURN 20   Checked first 50 results, not counting book reviews and a couple of duplicates. Most results were on-topic but only mentioned Mather in passing or fairly briefly.