When Does "J. Habakuk Jephson's Statement" (1884) Take Place?

"J. Habakuk Jephson's Statement" is a GENRE short story written by Arthur Conan Doyle that released January 1884. So when is "J. Habakuk Jephson's Statement" set? 


It takes place in the year: 

1873 AD

We know this because . 

Later, ? and the very first line of the first paragraph of the prologue reads "IN the month of December in the year 1873 the British ship 'Dei Gratia' steered into Gibraltar, having in tow the derelict brigantine, 'Marie Celeste,' which had been picked up in latitude 38° 40', longitude 17° 15' West." So it's December of 1873 AD at the end. 

Additionally, there's a two-part prologue: 

First, which "I was present at the second battle of Bull's Run and at the battle of Gettysburg. Finally I was severely wounded at Antietam, and"... the real-world Second Battle of Bull Run was fought on August 28th 1862 AD though August 30th, 1862 AD and the Battle of Gettysburg was fought from July 1st, 1863 AD to July 3rd, 1863 AD during the American Civil War. The first full scene follows the real-world Battle of Antietam, which occurred on September 17th, 1862 AD in the real world. So this part of the prologue takes place during (and probably after) September of 1862 AD. 

Then a second part includes a handful of scene and includes the sentences: "The next seven or eight years of my life were quiet and uneventful." and then, "I arrived in Boston on October 12, 1873"... So we pass quickly through 1865 AD or 1866 AD and it's almost certainly October of 1873 AD at the end of the multi-part prologue. 

1,873 - 7 = 1,866 

or 

1,873 - 8 = 1,865. 

HOWEVER, the Marie Celeste is certainly based on the real-world ship the Mary Celeste, found abandoned on December 4th, 1872 AD after leaving the real-world New York Harbor on November 7th, 1872 AD. So the ? could be a ? and the tale would therefore take place in November of 1872 AD to December of 1872 AD. 

1,872 - 7 = 1,865 

or 

1,872 - 8 = 1,864.