Here's where the First Mass Cav served. Note photo of its monument at Gettysburg (the unit had no casualties there).
http://www.civilwarintheeast.com/USA/MA/MA1cav.php

It's too late to thank these gentlemen, but I can publicly thank Munchdog for serving and helping to make sure that I was able to vote and had an election to judge 6 days ago.

I can't imagine the hardships and horrible (not horrific, I hate that word) sights these poor men had to endure by the time this was taken. The soldier with his hands folded in front of him seems to be attempting a smile, but he just can't bring it off. They look spent and exhausted.
Bless all of our warriors through all the wars.

http://deadconfederates.com/2012/01/05/diamonds-are-a-troopers-best-frie...

Possibly First Sergeant William Nickerson Davis, but he sure looks like Commissary Sergeant Ethan E. Cobb.

Mysteries, mysteries.

Dapper gent to [yes, Capt. Chas. F. Adams, elbow on knee, center] the left of him is Lt. Geo. H Teague; no-nonsense looking gent to his right is Capt. Edward A Flint.
Source: Civil War photographs, 1861-1865, compiled by Hirst D. Milhollen and Donald H. Mugridge, Washington, D.C., Library of Congress, 1961, item number 0385. For those who do not know, Milhollen was a Specialist in Photography at LoC in the 1950s; the catalog referenced is almost the "bible" when it comes to identifying 1,047 images. It was first printed in 1961; yes, there are likely some errors, but one must start somewhere.

It's photo day and I can't find my stinkin' hat!

I believe the bald officer in the center is Charles Francis Adams, Jr., grandson of John Quincy Adams and son of the U.S. ambassador to Great Britain at the time.

Those men look so tired and hungry! Long, long war slowly coming to an end!

Most officers learned early not to display their rank conspicuously, so as not to become a target for snipers. These fellows seem to feel secure enough to ignore that bit of field safety. If you got these guys to shave, they could pass for any photo taken with my buds in the Nam. Just as brave, dedicated and faithful, no matter what the folks back home thought, they were doing their best to protect the way of life they had sworn to preserve with their lives. And they did. Thank you, my brothers, It won't be long now, I'll be shaking your hands again, Bobbie, Howie, Rob and Kier.

First non-commissioned on the left standing has a diamond only on his sleeve. A First Sergeant would have sergeant's chevrons plus the diamond. Could this be a field make do for someone lacking sergeant's chevrons? I assume the diamond would have been interpreted as First Sergeants rank.

http://usarmyinsigniahomepage.110mb.com/civil_us.html
http://civilwarwiki.net/wiki/Union_Insignia_of_the_Civil_War

One thing I like to do is peruse the faces in these old pictures and see if any of them either look "familiar" and/or have a look I can imagine seeing at my local coffee shop. This group for the most part seems very much a part of their time/place (strange how faces can do that) BUT...the handsome, clean-shaven fella sitting on the left (second over)looks like boys I've seen at my daughter's school. THAT one can come visit my town anytime...what's 148 years after all?

I see the captain in the center of the photo has his insignia on his collar as do present day officers. I don't believe I've ever seen a photo of a Union Civil War officer wearing his rank in this manner. Most have their rank displayed on their shoulders.