Photographs of both Edwin V. Sumner & Staff, Philip Sheridan and his friend James Forsyth, aswell as Ulysses S. Grant & John Rawlins & a friend.
The interesting part about the Sumner photograph is that he and his son are touching by the knee, indicating (in those days), that they were close. The photograph dates to sometime in 1862, before Sumner retired in 1863, and died of a subsequent heart attack in his sleep, and unfortunately before he saw his son become Brigadier General of Union Cavalry (Hence Sumner Jr’s yellow sash).
The photograph of Philip Sheridan and James W. Forsyth is an incredibly interesting one. It’s after Sherman retired as General of the Army, and it’s before Sheridan’s mental and physical health deterioated severely, and it’s after Sheridan succeeded Sherman as General of the Army. He seems to be discussing some private matters with his good friend, and old Civil War Union Army buddy. Forsyth seems mad at whoever took the photograph, most probably because they caught Sheridan in an intimate moment; Sheridan isn’t wearing a uniform aswell, which is odd considering that Forsyth is.
The photograph of Grant dates to sometime in 1865, at the very close of the war. It’s outside of Grant’s headquarters in City Point, he’s seen together with his longtime friend, fellow (Brigadier) general John Rawlins. The man on the right is someone I’ve been unable to identify, it seems to be either a personal friend of Rawlins, or Grant’s, who might’ve just opted to be in the photograph - the other photographs of the same series shows Grant’s entire staff, while this is the only of the 2 Generals alone with anybody, which leads me to believe he’s someone dear to either of the generals.