that light, whether in the morning before sun rise, or in the evening after sun-set, supposed to begin and end when the least stars that can be seen by the naked eye cease, or begin to appear. By means of the atmosphere it happens, that though none of the sun's direct rays can come to us after it is set, yet we still enjoy its reflected light for some time, and night approaches by degrees. For after the sun is hid from our eyes, the upper part of our atmosphere remains for some time exposed to its rays, and from thence the whole is illuminated by reflection.