Head Northeast up the street, passing first Calvary Church, and a couple of blocks more the Metropolitan Life Insurance Company Tower.  In the next block up find 69th Regiment Armory and keep going to New York Life Building, taking the street at the building there Eastward. Go 5 blocks to 1st Avenue, then take that up north past a fountain, and a clinic, and just past the street after the clinic meet me at the post box on the opposite corner.