I BELIEVE this is a tin-type of Henry Norman Barnes Sr. and his 2nd wife  Sarah Jane Smalley, whom the family called "Sadie." 

I believe that Henry and  Sarah Jane were married in Taylor County, Iowa.  They had two children 
together - Lura Effie Barnes and George Cleveland "Cleve" Barnes.  

 Henry's first wife was Kathryn "Katie" Fitzsimmons, and the mother of  Henry Norman Barnes Jr., who was in the last photo I sent.
    

There is one more picture of Henry and Sarah Jane taken the same day,  and I believe that Mildred Tinder is in the photo with them.  I'm not 100%  sure about any of this, but I do know I've seen this picture before someone  in my own family has it.