Postcard of U.S. Cruiser "New York"

This post card features United States Navy Armored Cruiser "New York" that was commissioned in Philadelphia August of 1893 and decommissioned April 1933, and later scuttled in December of 1941.
Made in Germany by SL & Co. These ship postcards have a thin residue that feels like dried wax powder, I wonder if they were originally wax coated, because only on the 4 similar ship cards in the batch have this.