The photographer was A. Orr, Jr. of Glens Falls, NY. I did not find Orr in any census records but did find him listed on an 1876 map of Glens Falls on Ancestry.com. I also found several mentions of Orr when I Googled him, one in the "1871 Directory of Queensbury & Glens Falls" listed as "photographer, Traphagan's Building, Ridge." Another link shows a photograph with the photographer's mark, "C. L. Lovejoy successor to A. Orr, Jr. 1878" which suggests that either Orr sold his business before 1878 or perhaps died or moved from the area. This mention of him at craigcamera.com suggests that the photograph in question may be a picture of Orr himself.