The author appears to have regarded as akin to these meteors the star-like balls of light, which in stormy weather are sometimes seen on the masts of vessels at sea, and which before his time had been observed on the points of the spears of an army in the field. This luminous appearance, regarded by the Romans as a sign of the friendly presence of Castor and Pollux, is entirely atmospheric, and has no connection with shooting stars. It is now known as St. Elmo’s Fire, and has been shown to be a gentle continuous electric discharge from the earth towards a cloud. Seneca next describes in some detail a series of optical appearances connected with the sun and moon. Until the laws of the reflection and refraction of light had been discovered, it was obviously impossible to account for these phenomena. There is, therefore, much interest in following the lines of thought by which the old philosophers attempted to explain them. Seneca clearly perceived that the halos and coronae seen round the sun and moon in certain states of the atmosphere do not belong to these luminaries, but to our own air, and may furnish indications of coming weather. He remarks shrewdly enough that appearances akin to those seen in the sky may sometimes be observed in the thick moist air of a bathroom. But when he confidently proceeds to explain the meteorological phenomena he betakes himself to analogy, as he is so fond of doing. He remarks that when a stone is thrown into a pond a succession of circles is produced on the surface of the water, which continually widen from the point of impact until they lessen and disappear. In like manner he believes that when the light of the sun or moon strikes the cloudy air it produces a similar effect, for as every kind of light is round in shape, the air is thus driven into a circular form. His love of analogy generally, as in this instance, leads him far away from the truth, and prevents him from seeing the palpable flaws in his reasoning. But the apparent similarity of appearances, which are in reality entirely dissimilar, contents him with his explanations.