Also, both Sen. Tim Scott (R-SC) and new Sen.-designate William Cowan (D-MA) were appointed by governors, not elected. Scott replaced Sen. DeMint when he left to lead the Heritage Foundation, and Cowan was just announced as the replacement for Sen. Kerry, who's about to become secretary of state. That doesn't make Scott and Cowan any less legitimate as legislators, but it also doesn't give their states' voters a milestone to take credit for.
Cowan brings the grand total of black senators in history to eight, only three of whom were elected by popular vote. I'm proud of the fact that two of the three (and three of the eight) represented the great state of Illinois. I'm less proud of the fact that popularly electing two black senators over the years is all it takes to be first among the states. Massachusetts is second with one, and then there's a 48-way tie for third.