The Liberator was the preëminent Anti-slavery newspaper in the U.S., published by radical abolitionist William Lloyd Garrison. The attached issue includes, on page 3 (135), a report from the Nantucket Anti-slavery meeting to which Garrison refers to in this Preface. The brief notes reference a "--- Douglas" who spoke on Wednesday, August 11, 1841.
Source: The Liberator. Vol. 11, No. 34 (20 Aug. 1841). American Periodical Series, University Microfilms International, Ann Arbor, Mich, 2014-2016. http://fair-use.org/the-liberator/1841/08/20/the-liberator-11-34.pdf