Pianoforte concerto no. 4, in B flat
This work is listed in the 1878 programme as pianoforte concerto no. 4 in B flat. Perhaps it was known as that number in 1878 but the musical illustrations shown in the 1878 programme correspond with the pianoforte concerto now identified as no. 15 in B flat and the link from the 1878 concert now goes to that work.