Statistics for occurrence #1 of “Doc” in year 1863, month March of Rebellion Record: a Diary of American Events, Diary from December 17, 1860 - April 30, 1864:

...his day bombarded by a fleet of iron-clad monitors and mortar-schooners, under the command of Captain Drayton; but, after an almost incessant fire of eight hours duration, they failed to reduce it.--( Doc . 129.) John Maginnis, late editor of the New Orleans True Delta, died this day.--A grand review of the rebel forces at Mobile, Ala., took place this day, by Major-Generals Withers and Buckner, ...
Max. Freq. Min. Freq.
Entity Corpus Doc Corpus Doc  
Doc 6,842 2,810 2 0 0 user votes
N. Y. Doc 1,108 0 0 0 0 user votes
Y. S. M. Doc 78 0 0 0 0 user votes
London Doc 4 0 0 0 0 user votes

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