While searching some information on topic "Civil War in Rhode Island", I've found a copy of letter which was written by one participants. Here is the piece that impressed me the most:

"But, O Sarah! If the dead can come back to this earth and flit unseen around those they loved, I shall always be near you; in the brightest day and in the darkest night—amidst your happiest scenes and gloomiest hours—always, always; and if there be a soft breeze upon your cheek, it shall be my breath; or the cool air fans your throbbing temple, it shall be my spirit passing by."

This letter was written by Sullivan Ballou (March 28, 1829 – July 28, 1861). He was a lawyer, politician, and major in the United States Army. He is best remembered for the eloquent letter he wrote to his wife a week before he fought and was mortally wounded alongside his Rhode Island Volunteers in the First Battle of Bull Run.

Here you can find some more information:
http://en.wikipedia.org/wiki/Sullivan_Ballou
http://www.historynet.com/sullivan-ballou-the-macabre-fate-of-a-american-civil-war-major.htm
Using this link you will find a short information(also some photos are included):
http://www.findagrave.com/cgi-bin/fg.cgi?page=gr&GRid=1800