THE INVESTIGATION IN 1922: METHODS EMPLOYED

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 15-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 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 dipneedle compass is so arranged that the needle swings in a vertical instead of in a horizontal plane. It is used to detect differences in magnetic attraction. Three stations were occupied--one on 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 vertical angle, but occasionally a light remained visible for so short a time that it had disappeared before 1 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 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.

Figure 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. 1). 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.

OBSERVATIONS AT LOVEN'S

At station A near Loven's Hotel, various lights were observed and studied. The lights were seen in an arc between Lenoir and line 3 over Brown Mountain, associated with the name "Brown Mountain light." Observations included lights from trains, automobiles, and an unexplained light, possibly the Brown Mountain light, viewed at different times and positions.

OBSERVATIONS AT GINGERCAKE MOUNTAIN

At station B on Gingercake Mountain, the lights were seen over a larger arc with Brown Mountain covering half of it. Observations included lights from locomotives, automobiles, and possibly brush fires. There was a notable observation of a light near the dam on Linville River. Various lights seemed similar, and unfavorable conditions led to limited observations on certain nights.

OBSERVATIONS AT BROWN MOUNTAIN

An expedition to Brown Mountain was hindered by rain and fog. While no lights were seen, the conditions and the circuit made around the mountain made it likely that any lights arising over the mountain would have been noticed, but none were observed.

CONCLUSIONS

The writer feels confident that the lights he saw were actually a fair average display of the so-called Brown Mountain light. The lights observed have nothing in common with the Andes light or with St. Elmo's fire. There is no geologic basis for the idea that the lights seen are natural wonders of any sort, but there are certain interesting surface features and atmospheric conditions that are effective in producing some of the appearances of the light.

By reference to the map it will be noted that the Catawba Valley east of Marion is a basinlike area--an area nearly surrounded by mountains, of which the Blue Ridge on the north, with its fringe of southward-projecting spurs, is the highest and most rugged part. After sunset cool air begins to creep down the tributary valleys into the basin, but the air currents come from different sources and are of different temperature and density. The atmospheric conditions in the basin are therefore very unstable, especially in the earlier part of the evening, before any well defined circulatory system becomes established. At any given place in the basin the air varies in density 15 degrees during the evening and hence in refractiveness. The denser the air, the more it refracts light or bends waves of light emanating from any source. The humidity of the air affects its density and hence its refractive power. Mist, dust, and other fine particles tend to obscure and scatter the light refracted and to impart to it the reddish or yellowish tints so frequently observed. Thus it is that the light is most active in a clearing spell after a rain, as noted by many observers. When the mist is very dense, the light is completely obscured. Lights that arise from any source in the basin are viewed at low angles.

Probably few if any basins on the Blue Ridge front are so favorably located as to show as well as this one the atmospheric phenomena described, and the opportunities here for the observation of such phenomena are perhaps no less exceptional. Loven's Hotel and Blowing Rock, which are resorts that attract fishermen or tourists, are among the most favorable places of observation. The valley is fairly well settled and has a network of roads, three railroads, and several large towns, so that the possible sources of light are very numerous. As the basin and its atmospheric conditions antedate the earliest settlement of the region, it is possible that even among the first settlers some favorably situated light may have attracted attention by seeming to flare and then diminish or go out. As the country became more thickly settled the number of chances for such observations would increase. Before the advent of electric lights, however, it is doubtful whether such observations could have been sufficiently numerous to cause much comment, though some persons may have noted and remarked upon them.

According to local estimates electric lights have been in use in the larger towns of the region for about 30 years. The use of powerful electric headlights on railway locomotives, which began about 1909, furnished new sources of strong lights in the valley and introduced an element of regularity in their appearance. In 1910, the Brown Mountain light began to acquire notoriety. Meanwhile, automobiles were coming into use throughout the country, and many of them were equipped with powerful headlights. Within the last few years their number has been greatly increased, and this fact is in keeping with the general deduction already made--that on a favorable evening the lights are seen more frequently now than formerly. During the flood of 1916, when train service was temporarily discontinued, the basin east of Marion, where the atmospheric conditions are disturbed, was still the scene of the intermittent flare of favorably situated lights. Automobiles were then in use in the larger towns and on some of the intervening roads, and their headlights were doubtless visible from Loven's over Brown Mountain. One need only remember the network of roads in the valley region (see topographic maps of the Morganton and Hickory quadrangles) to realize the almost infinite number of possibilities for automobile headlights to be pointed toward Brown Mountain and stations of observation beyond. It should be emphasized, too, that automobile headlights and locomotive headlights, when seen at distances and under atmospheric conditions such as those which prevail in this region, possess no characteristic that clearly distinguishes them from other lights. On the contrary, as stated by the lady at Blowing Rock, they look "as much alike as so many peas in a pod," though this statement should not be understood to mean that some may not be brighter than others.

The behavior of headlights in the Brown Mountain region in this respect is comparable to that of the lights in the lighthouses on the Atlantic Coast. From the seawall at Gloucester, Mass., the writer has repeatedly seen the light at Minots Ledge, southeast 17 of Boston, nearly 25 miles away in a direct line. This light is identified by a series of flashes that may be represented by the numerals 1-4-3. There is no beam and there are no rays. The light cannot be seen unless the air is fairly clear. Then it simply flashes once, four times, three times, and it has much the same appearance as the Brown Mountain light. The supposed motion of the light at times may be due to errors of observation.

Some years ago McNeilly Du Bose, an engineer then employed near Morganton, tested observations made by himself and others by tying a cord across the fork of a tree in a place where he could see the light across the cord and was surprised to find that the light was stationary with respect to the cord. Professor Perry, whose letter has been quoted, notes that the light was uniformly stationary when he saw it. The eye is easily deceived at night as to the stability or motion of an object, and an observer's impressions are to a considerable extent affected by his mental and physical condition at the time of observation. It is not surprising that under the circumstances different eyewitnesses give quite different accounts of the light, especially as the light may appear suddenly against a dark background with nothing nearby that can be used as a scale to determine its size or its possible motion.

In summary it may be said that the Brown Mountain lights are clearly not of unusual nature or origin. About 47 percent of the lights that the writer was able to study instrumentally were due to automobile headlights, 33 percent to locomotive headlights, 10 percent to stationary lights, and 10 percent to brush fires.