The world’s richest man, Microsoft Chairman Bill Gates, is apparently getting more generous with his estimated $60 billion fortune as he gets older. Gates and his wife, Melinda, donated $100 million Wednesday to provide life-saving vaccines for children in Third World countries. The couple said the money will set up the Bill and Melinda Gates Vaccine Program, which will provide immunizations against respiratory illnesses and diarrhea. Last week Gates gave $20 million to the Seattle Public Library. This generation’s billionaires have been criticized for not engaging in the kind of philanthropy that marked the robber baron days of the Rockefellers, Carnegies and Mellons.