The rate of decay of light from a persistent meteor train was measured using a microdensitometer. The decay followed an exponential law at all measured points, and these points were located between heights of 84 and 93 km above the earth's surface. At 93 km the light decayed at a rate of 0.2 magnitudes per second; at 84 km the rate was 1.2. Evidence of radiation from atomic oxygen was found in the early part of the decay curve. A comparison of normal and long enduring trains shows that the rate of decay is controlled by the upper atmosphere and is not dependent on the properties of the meteor that produced the train.