Appleton, Wis.. April 13.- Arthur C. Lunn of Lawrenco university watched the supposed airship carefully Monday night, and, after calculation has proven beyond a doubt that the supposed shlp is the star Betelguese in the constallation Orion. There was some excitement on the streets Monday r.ight when a peculiar ight was seen in the west. The light was no larger than a large star, but changed color from red to a piércing white, elosely resembling an electric searchlight at several miles distant. What was even more peculiar the "airship" seemed to bob up and down with at times a lateral motion. When flill some degrees above the horizon, it disappeared, reappeared again in an instant, and finally became invisible. Students of Lawrence university who saw the phenomenon callecl up A C. Lunn, recognized as an expert ii - - tronomy by all the members cf the - ilt'y, and he took close observations of he star, as he termed it. ( aU-ulations Coincide. The star finally set at 10:40 and Mr. liunn recorded the angular distance 'lom the west point, together with the time of the apparent setting of the star over the sensible horizon. Tuesday afternoon Mr. Lunn calculated the anguar position and setting time of the real star. taking the mean of the atmospheric refraction. The two calculations, he une on the airship and the star Betelguese, coincide within the posible imit of error in the eye estímate, which is very low. Mr. Lunn made a very comprehensive explanation of the Ilusión, saying that Betelguese is a red star with a light of a quality that greatly exaggerates the twinkle of all stars when it is near the horizon. Atmcspheric disturbances easily occur and in. a moment's time will make the atmosphere much more dense, causing a greater refraction of some of the light rays. AVhen, for example, two red rays near together in the spectrum are refraeted so that at a given point there is a certain difference in the wave length, interference occurs and neither ray is visible. Kxplams the Different Colors. This. with ether phenomena of refraction, explains the different colors manifested by the star and the same principie of refraction also explains the apparent vertical vibration of the stai v.hich Mr. Lunn gave as being Monday night at least 35 minutes. A lateral vibration was also notieed and though not so evident, was still present. This vibration is now being studied by astroncmers at Yale college. Mr. Lunn ex plained thé movement stated from southeast te northwest in the following manner: The first appearantfe in the southeast might be due to the rising o Antares, a red star of the same magni tude of Alpha Orionis; and af ter it ha risen, the western star is seen going through the same movement in th northwest. While rising in the east. th stars pass the meridian considerably to the south of this latitude.