Your information is welcome. The 1890 Census is far from perfect and just because it states service for the CSA it doesn't make it so.
I just found Maximillian Maurice Hemmer listed in the NY AG's records in the 1st NY Engineers as "Morris Hemner". He applied for a government pension as "Maurice Hemmer" No wonder that I couldn't find his service since I was looking for Maximillian Hemmer. I suspect he is one and the same soldier listed in the census.
I would like to add his name to OBGB if you can tell me the cemetery name and location. I have a copy of his pension card which shows that he diedon 4/19/1919 at Newark, NJ.
I can e-mail you a copy of his pension card if you want it. Contact me at: