The Speed of Light
Careful measurement in the laboratory on earth (Fizeau) around 1850 gave a more accurate value
By the time Maxwell published his equations (1873) the speed of light was rather well established Accepted value now c = 299,792,500 m/s or c = about 300,000,000 m/s = 3 x 108 m/s = about 186,000 miles/sec