Searching for all the information available regarding a rear barrel sight designed by A. T. Decker.  He was a Lt. in the New York State Militia in 1878. The sight was installed on Remington rolling block carbines that NYS had purchased.  The Decker sight was installed to allow the carbines to be shot more accurately at longer distances.
Decker and his sight are referenced in the Adjutant Generals Report (1878). Inventory record seems to indicate the NYS had 587 of those sights.  Being digitally challenged I have not been able to locate any patent information, drawings, or even photos of the complete sight after hours of internet surfing...   While I have a couple of the sights with missing parts,  I can not restore them without more detailed information.
Any assistance will be greatly appreciated.