These are all 2nd Lieutenants in the 4th U.S. Artillery, C-1870s.
This tintype was taken in the period of 1872-1881, and with what appears to be a buffalo robe in the forefront of the image, it certainly has the western look. The four officers in this photo are all in uniform, 2 in full dress and the others in fatigues. All of the men are 2nd lieutenants. Note the lone 1860 sword, and by the shape of the drag on the scabbard is Springfield Armory made. Three are posed in that typical Victorian era “far off contemplating look.”
The 4th officer has taken a rather cavalier stance, head cocked, hand on hip, the right forearm resting on the shoulder of another officer, while holding that sword. Yes I did say right forearm, for if you look at the regiment numeral “4” on the forage cap of the one officer on the left, you will see that the image is presented in the backward fashion, commonly seen in tintypes (that’s why they always thought that Billy the Kid was left handed).
Interesting thing about that forth officer in the forage cap, He is a woman. Best I can figure, she is a wife or sweetheart of one of these three. Very delicate hands with a ring on the finger, that might be an engagement ring.
The 4th Artillery saw a good deal of service in the 1870’s out west in several campaigns; not all companies acting in unison, in California, Alaska, the Plains, Idaho, etc.
Condition is very good, in the original oval frame is covered in gesso, painted black and probably originally in gilt, some minor repairs to frame. Size of image is 4 x 5 1/2 inches.