Question: where was uncle tom's cabin first published
[{'answer': 'The National Era', 'provenance': [{'wikipedia_id': '71989', 'title': "Uncle Tom's Cabin", 'start_paragraph_id': 12, 'start_character': 59, 'end_paragraph_id': 12, 'end_character': 75, 'bleu_score': 1.0, 'section': 'Section::::Publication.\n'}]}, {'answer': 'The National Era , an abolitionist periodical'}, {'answer': 'in The National Era , an abolitionist periodical , starting with the June 5 , 1851 , issue'}, {'provenance': [{'wikipedia_id': '71989', 'title': "Uncle Tom's Cabin", 'start_paragraph_id': 12, 'start_character': 0, 'end_paragraph_id': 12, 'end_character': 629, 'bleu_score': 0.9486604584788991, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3000856484039892016}, 'section': 'Section::::Publication.\n'}]}, {'provenance': [{'wikipedia_id': '71989', 'title': "Uncle Tom's Cabin", 'start_paragraph_id': 0, 'start_character': 0, 'end_paragraph_id': 0, 'end_character': 0, 'bleu_score': 1.0, 'meta': {'yes_no_answer': 'NONE', 'annotation_id': 3000856484039892016}, 'section': 'Section::::Abstract.'}]}, {'provenance': [{'wikipedia_id': '458692', 'title': 'E. D. E. N. Southworth', 'section': 'Section::::Life and career.\n', 'start_paragraph_id': 7, 'end_paragraph_id': 7, 'meta': {'evidence_span': ['published in the "Baltimore Saturday Visiter". Some of her earliest works appeared in "The National Era", the newspaper that printed "Uncle Tom\'s Cabin".', 'The National Era", the newspaper that printed "Uncle Tom\'s Cabin"', 'The National Era']}}]}, {'provenance': [{'wikipedia_id': '71989', 'title': "Uncle Tom's Cabin", 'section': 'Section::::Publication.\n', 'start_paragraph_id': 12, 'end_paragraph_id': 12, 'meta': {'evidence_span': ['"Uncle Tom\'s Cabin" first appeared as a 40-week serial in "The National Era",', '"Uncle Tom\'s Cabin" first appeared as a 40-week serial in "The National Era", an abolitionist periodical, starting with the June 5, 1851, issue.', 'The National Era']}}]}, {'provenance': [{'wikipedia_id': '37894082', 'title': 'The National Era', 'section': 'Section::::Abstract.', 'start_paragraph_id': 1, 'end_paragraph_id': 1, 'meta': {'evidence_span': ['The National Era was an abolitionist newspaper that ran from 1847 to 1860. Published weekly in Washington D.C., it contained seven columns and was four pages long. "The National Era" was noted for its large size and unique type. It featured the works of John Greenleaf Whittier who served as the associated editor and the first publication, as a serial, of Harriet Beecher Stowe\'s "Uncle Tom\'s Cabin" (1851). "The National Era Prospectus" stated in 1847: Two months after the establishment of "', 'It featured the works of John Greenleaf Whittier who served as the associated editor and the first publication, as a serial, of Harriet Beecher Stowe\'s "Uncle Tom\'s Cabin" (1851). "The National Era Prospectus" stated in 1847: Two months after the establishment of "', 'The National Era']}}]}]