If your Milwaukee German ancestor was buried in one of the Milwaukee Catholic Cemeteries, you can search their database online at http://www.cemeteries.org/genealogy.asp. Most of my Germany family in Milwaukee was Catholic so this database is a treasure to me.
Doing a search for Ferdinand Bartels produced two results: Ferdinand Bartels and Ferdinand Carl Bartels, both buried in Calvary Cemetery. When I click on the name "Ferdinand Bartels - Calvary Cemetery," I am taken to the results page for him which lists the following information:
Name: Ferdinand Bartels
Date of Death: 3/25/1915
Date of Burial: 3/25/1915
Age at Death: 29
Marital Status: Unknown
Last Address: 707 1 Ave
Funeral Home: Alstadt &
Cemetery: Calvary Cemetery
Location: Block: 21Section: Row: 145s
(This Ferdinand Bartels is the son of Ferdinand Carl Bartels.)
There is also a feature below this data display that enables me to search nearby graves or crypts. When I do this, I find other Bartels family members, including a married daughter (Caroline Kramer) listed in the adjacent graves.