Consider the four hall marks below shown on the page dealing with reading marks on plates –

The third hallmark is likely a ‘Black Letter’ small ‘S’ – obviously to William Howard it meant something. Perhaps the surname of the man to whom he was apprenticed, perhaps even his town or street address. We do not know.
Sometimes these letters are so complex as to make the reading of them to those unfamiliar with such alphabets very difficult indeed. Eventually I found a likely alphabet that has helped me identify many of the letters that might be found and it follows below in this section, with additional notes on the letters e, and s.