Méthodes employées

After a conference in Morganton with men who are familiar with the lights the writer set out to take observations at the place near Loven's Hotel and at other places from which, according to reports, the lights could be seen, Brown Mountain itself being one of the places. The instruments used consisted of a l5-inch planetable (a square board mounted on three legs), a telescopic alidade, pocket and dip-needle compasses, a barometer for measuring elevations, a fieldglass, a flashlight, and a camera, besides topographic maps of the region.

In making the observations a topographic map was fastened flat on the board, which was leveled and the map turned to a position in which the directions north, south, east, and west on the map correspond with the same directions on the ground. Sights were then taken to known landmarks with the alidade, which is essentially a ruler fitted with a sighting telescope, and corresponding lines were drawn along the ruler on the map. The meeting point of the lines thus drawn marked the location of the observer's instrument on the map. From this location, which was determined in the daytime, sights were taken at night with the alidade on the map. The telescope of the alidade swings in a vertical as well as in a horizontal plane and can therefore be used for measuring vertical angles along the lines of sight. The dip needle compass is so arranged that the needle swings in a vertical in- stead of in a horizontal plane. It is used to detect differences in magnetic attraction.

Three stations were occupied--one In the knoll by the cottage formerly occupied by Rev. C. E. Gregory, near Loven's Hotel; one in a field on the east slope of Gingercake Mountain; and one on the terrace in front of the summer residence of Miss Cannon, at Blowing Rock. These stations are marked on the map (fig. 1) by the letters A, B, and C, respectively. Two nights were spent on Brown Mountain, but the conditions were so unfavorable that no station was occupied there. At each station at which observations were made, vertical angles to parts of Brown Mountain were noted, dip-needle readings were made, and photographs were taken. Vertical angles were also measured when practicable from each station to each light seen. The procedure adopted was first to get a line of sight to the light and then to note its time of appearance and measure its verticlal angle, but occasionally a light remained visible for so short a time that it had disappeared before the telescope could be trained upon it and a line drawn to fix its direction. Few records were kept of lights for which lines of directions were not drawn, but the total number seen may have been nearly twice the number recorded. The atmosphere proved too hazy for satisfactory photographs. The train registers at Connelly Springs and at Hickory were examined, and subsequently train schedules for the evenings of observation were obtained from many station agents throughout the region.

The observations obtained in the field were afterward adjusted on the map. Many profiles along lines of sight were constructed, the vertical angles were plotted, and corrections for the curvature of the earth's surface and for refraction were made. In this way the sources of some of the lights were approximately determined. The inset profile (fig. 1) illustrates the method of locating a source of light by means of a profile and vertical angle drawn from station B along line 15.

Space does not permit a detailed statement of the individual observations made and of the inference drawn from them. The geographic positions of the sources of light as determined by instrumental observations are only approximate because of the difficulties attending the use of the instruments in darkness. The stations were from 1,000 to 1,500 feet higher than the summit of Brown Mountain, so that the lines of sight to the lights seen all passed several hundred feet above the top of the mountain as shown in inset profile (fig. I). This fact caused the lights to appear over the mountain rather than on or below its crest, a feature noted both in the first published description of the lights, in the Charlotte Observer, and in Professor Perry's description, already quoted. The appearance of the lights as described in these two accounts, especially in that given by Professor Perry, agrees so closely with their appearance as observed by the writer that no additional description of them need be given here.