Popular Science Monthly/Volume 70/June 1907/A Blazing Beach
| A BLAZING BEACH |
By D. P. PENHALLOW, D.Sc, F.R.S.C.
MACDONALD PROFESSOR OF BOTANY, MCGILL UNIVERSITY
IN December, 1905, an account was given in Science[1] of a remarkable phenomenon which was described as 'A Blazing Beach' as observed at Kittery Point, Maine, and an attempt was then made to bring forward an explanation which would satisfactorily account for all the observed facts. During the past summer an opportunity was offered for a reexamination of the locality, and it was then possible to obtain some additional facts which tend to strengthen the conclusions originally reached. It was also learned that a second but smaller conflagration had occurred in the same place at a somewhat later date. It is therefore felt that a further account of the facts will be of interest at this time.
The accompanying photograph, taken during the past summer, shows the precise area within which the conflagration developed. The beach at the point where the fire occurred is composed of a barrier ridge at its upper margin, made up of pebbles of varying sizes. This ridge is thrown up and maintained under the action of southeast storms, at the angle of repose for the material of which it is composed, and about half-way down its outer face, the high water mark of spring tides is clearly indicated by patches of sea-weed. This high-water mark corresponds approximately to the level of the interior area where the trees are to be seen growing, and which is frequently flooded in times of severe southeasterly storms. The base of the barrier ridge is indicated by the line of sea-weed which defines the high-water mark of the ordinary neap tides. From this point the beach, consisting of pebbles, continues outward and downward at a somewhat sharp incline for a distance of about seventy-five feet, when the pebbles are replaced by sand, the first patch of which is seen just above the line of water. The photograph shows half-tide.
The sand formation extends from the edge of the water outward with a very gentle slope, and thus makes shoal water for a considerable distance beyond the mass of loose rock seen on the extreme left. With the exception of the barrier ridge, the beach extends laterally for a distance of one hundred and seventy-five to two hundred feet between the solid ledges shown in the photograph. The general constitution of the shore along the river front is solid ledge, and this particular locality may be described as a pocket which has become filled with sedimentary deposits consisting of clay, sand, sand and gravel, coarse gravel and finally large pebbles.
Over the outer portion of the sandy bottom, also for great distances beyond, as well as up and down the river wherever extensive silting has developed the formation of muddy bottoms, there is an abundant growth of eel grass (Zostera marina) which, together with other débris of a similar nature, is continually washed upon the beach, broken up by the combined action of the waves and sand and gradually buried in the latter, so that each year the deposit of organic matter is increased by definite though rather slight increments.
From these data it will be observed that some special significance attaches to the fact that the fire, on two separate occasions, was strictly confined to the beach, and that it did not in any way extend over the limiting areas of rock.
On the evening of Friday, September 1, 1905, the guests in the hotel, the piazza of which may be seen on the extreme right of the photograph, were startled by the appearance of flames rising from the beach and also from the surface of the water. The tide was about one hour lower than shown in the photograph, so that a very considerable portion of the sand was uncovered. The conflagration occurred between seven and eight o'clock in the evening and lasted for upwards of forty-five minutes. It was accompanied by a loud and continuous crackling noise, which could be distinctly heard one hundred yards distant, due to the rapidly recurring explosion of bubbles of gas as they came to the surface of the sand or water. At the, same time there was a very strong liberation of sulphurous acid gas, which penetrated the hotel, drove the proprietor and his staff from the office and filled the other rooms to such an extent as to cause great inconvenience to the guests. So great a heat was developed that the sand could not be held in the hands, while sand placed in a tumbler with water and then stirred, liberated bubbles of gas which ignited upon coming in contact with the air. On this occasion the fire developed over that portion of the sand which had been exposed by the falling tide, and it also extended out over the water for a distance of thirty or forty feet.
On the evening of Wednesday, October 4, 1905, as reported by a reliable observer, the phenomenon was repeated with identical features, except that instead of occupying the entire area between the rock formation on each side, it was restricted to the area where the two boats are lying. It therefore occupied probably less than one fourth the area of the first conflagration.
It is difficult to estimate the height of the flames on these two occasions, since the conditions under which the fire occurred would tend to give an exaggerated value. It is probable that in general the flames were not more than three or four inches in height, and this would be a reasonable estimate when arising from small bubbles of gas. But, as stated in the original account, the flames attained a maximum of about one foot, and this may readily be conceived of as possible in cases where there was an unusual discharge of gas.
The explanation originally offered appears to fulfill all the observed conditions, and upon further study there seems to be no good reason for regarding it as other than valid. The flames are to be considered as resulting directly from the spontaneous combustion of light carburetted and phosphuretted hydrogen at the moment of their contact with the air, and these flaming gases in turn ignited the associated sulphuretted hydrogen, which gas then gave rise to secondary features such as the bluish, luminous flame and the sulphurous acid fumes. Examination showed that there was no adequate basis for any of the various attempts to explain the phenomenon as the result of volcanic action, the disruptive effects of a blast of fifty tons of dynamite two miles away, or the decomposition of fish, the phosphorescence of which was not clearly differentiated from the main features of the conflagration.
While it is a comparatively simple matter to reach the conclusions thus far given, it is altogether a more serious problem to ascertain the origin of the gas, the greatest difficulty being to determine how gas could be produced in sufficient quantity to give rise to a conflagration of the extent and duration observed. It is perhaps justifiable to conclude that the gas must have been accumulating at a slow rate for a long time, otherwise there would not have been such a large volume; and it is also reasonable to suppose that, unless liberated as fast as formed, smaller conflagrations should have been noted on previous occasions. But the local records, so far as the memory of 'the oldest inhabitant' extends, can show no similar occurrence in the past. Such storage of gas would be quite possible in a deposit of coarse gravel, pebbles and coarse sand, overlaid by a layer of fine, wet and compact sand acting as a retaining layer. It is possible, also, that the accumulation of gas may have been brought about under slight pressure, so that the earthquake of the day before may have furnished just that shaking which was necessary to disturb the conditions of equilibrium and liberate the gas at a critical moment. The occurrence of a smaller conflagration one month later may or may not harmonize with this idea, but it does seem to emphasize the suggestion of the storage of large volumes of gas which were not wholly set free on the first occasion. In endeavoring to account for the source of the gases, three explanations have been found to be possible:
1. The area protected by the barrier beach is, as already noted, somewhat depressed. It extends from the beach to a stone wall which may be seen just beyond the two elm trees; and from the square house to an almost equal distance beyond the corner of the hotel piazza on the right. It was originally occupied by Sir William Pepperrell as a deer park, but later it was utilized as a tan-yard.
Some years since two drains were laid through this area in such a way as to make sections of its entire extent. The ditches were carried down through the superficial deposits to a clay formation, which is presumably of Pleistocene age, and this clay formed the foundation for the tan vats located in the surface stratum. The excavations disclosed numerous, scattering fragments of leather and tan bark, sufficiently ample to make the former use of the locality quite manifest; but nowhere were there any local accumulations of a nature or in such quantity as to explain the formation of gas in any appreciable volume. Moreover, had gases formed there they would most naturally have worked upward through the permeable soil and thus they would have escaped directly into the atmosphere rather than have taken a seemingly impossible course down a slope for a distance of some two hundred feet or more. It is, moreover, about eighty years since tanning operations were carried on in that locality, and the conditions of the soil render it unlikely that any very large amount of gas could be stored there for that length of time. The theory that the gases had their origin in the decomposing organic debris of a tan-yard must therefore be dismissed as untenable.
2. The Atlantic coast line, probably throughout its entire extent, is undergoing depression at the rate of about two feet per century. This leads to a variety of well-defined changes, among which may be mentioned the gradual silting up of protected areas, the submergence and final burial of forests and the formation of marsh lands. Nowhere are these changes better exemplified than in the neighborhood of Eye in New Hampshire, and Kittery and York in Maine, for the reason that they are developed within areas of such size, and within periods of such short duration, as to be brought well within the experience of individual observers.
Wherever silting occurs, and more particularly where marsh lands are formed, large volumes of gas are generated and may be readily observed rising to the surface of the water at more or less frequent intervals. In the case of the silted areas the gas is obviously the product of vast quantities of Zostera, supplemented by other forms of organic remains, both plant and animal. In the marsh lands the gas is the normal end product in the decay of the lower portions of the marsh turf. This gas generally accumulates in the turf and in the silt below, sometimes being held in pockets in such large volume that when suddenly liberated its effects are overpowering. For one who is at all acquainted with such marsh lands it is not difficult to reach an explanation as to the production of gas in sufficient volume and of the proper kinds to produce all the phenomena under consideration. It was therefore felt that there might be a small, buried marsh beneath the beach at Kittery Point, and an attempt was made to solve the question by direct examination, with the following results:
For a depth of about seven inches the beach consists of a fine and compact sand worked into a layer of great firmness. Below this, as far down as it was possible to go without the use of special methods, the deposit consists of large beach pebbles mixed with coarse sand. So far as a buried marsh was concerned, the results were entirely of a negative character, but from the fact that there is a deposit of clay farther down, as well as from critical studies of the formation of marsh lands and of silted areas, prosecuted during the past summer, there seems to be great probability that one or both of such formations may lie beneath the beach at a horizon which could not be reached. In the absence of positive data, however, this source of gas must be
neglected, and the third alternative must be brought under consideration.
3. In making a section of the lower beach, as already recorded, it was observed that the superficial layer of sand, that which is directly acted upon by the water, consists of about one inch of freshly washed, fine sand with which are mingled numerous fragments of marine plants and even fragments of land plants, most of them in a fresh state but broken into small pieces by the recent action of the water and sand. Below this is a deposit of sand about six inches thick. This layer rests directly upon a mixture of beach pebbles and coarse sand extending to an unknown depth. It is the six-inch, or second, layer in which interest chiefly centers, since we find it to contain all sorts of organic debris, including marine algae, fragments of drift wood and bones of land animals. It in fact constitutes the general receptacle for all those organic remains which have been ground up in and transferred to it by the surface layer. It is clear that while this second layer may remain of approximately equal thickness, its organic content is constantly augmenting and at the same time undergoing decay. This is finally expressed in the deep black color of the stratum, by the carbonized fragments of marine algae, driftwood and even of bones, showing that within this zone there are developed precisely those conditions which would be productive of gases in considerable volume.
It is this last explanation which affords the chief basis of a tentative hypothesis respecting the origin of the gases producing the conflagrations, though it is also highly probable that other volumes of gas originated at a greater depth in a buried marsh, or in silt deposits which were subsequently overlaid by a pebbly beach.
This phenomenon, while peculiarly interesting in itself, serves as a means of explaining the possible origin of many obscure forest fires for which it has hitherto been impossible to find an adequate explanation, and in considering this important aspect of the question we are not to overlook the possibility of accounting for fires which have occurred in past geological ages, as well as those of recent date.
In 1905, Arthur Hollick directed attention to the presence of charred wood in the Cretaceous deposits at Kreischerville, Staten Island, New York, and drew the inference that since man was not in existence at that time, the fire must have been due to some natural agency, probably lightning. This explanation, however, was not regarded by him as wholly satisfactory, and it was adopted tentatively because of the absence of positive testimony in any other direction, and also because the occurrence of fires in widely separated localities of approximately the same geological age could not be accounted for through the medium of such an agency.[2] In a more recent communication on this subject,[3] the same author observes that some of the fragments of burned wood are charred on the outside only, while other smaller fragments are completely charred throughout. "These latter occur in greatest abundance in connection with layers or seams of yellowish, sandy clay. The prevailing colors of the Cretaceous sands and clays throughout this locality are white and gray, while the yellow layers are of quite limited extent and appear to have been burned or baked. It seems therefore reasonable to infer from this association of materials, that the charred wood was not deposited with the clay in the condition of charred wood, but that it was fresh material at the time of deposition and was subsequently burned in place, thus baking the enclosing clay."
"A careful study of the Kreischerville deposits indicates very clearly that the original conditions of deposition must have been strikingly similar to those described as existing at the Kittery Point Beach. The layers of vegetable debris and sand, intercalated in the clays are comparable to the sandy layer of black, organic débris in the beach, and it is reasonable to infer that wherever such conditions prevail, similar phenomena of combustion may occur," and he therefore finds that the explanation of the Kittery phenomenon is not only satisfactory in that case, but that it affords a satisfactory solution of the way in which fires originated in Cretaceous time.
In 1900, Dr. G. F. Matthew of St. John, N. B., described a bog in the vicinity of that city which gave evidence of the occurrence of a forest fire about two thousand years ago, this estimate of age being based upon the age of growing trees, the thickness of individual layers of peat, and the relative density of different layers, together with the known rate of formation as determined by the age of trees in situ.[4]
Evidences of ancient forest fires are to be met with in other bogs to which Dr. Matthews directs attention, and it is altogether probable that they had a similar origin. The agency of lightning is excluded as not tenable because of the thorough knowledge of the bogs in question for a period of from 6,000 to 9,000 years, and from the evidence at hand the conclusion is reached that they must have been due to the early inhabitants of the district who knew nothing as to precautions against the spread of fire, and who would have been but little likely to have adopted them had they been known.
Upon a careful examination of the account given by Dr. Matthews, it would seem that the situation of the burned wood within the area of a bog is a distinct argument against man as the active agent, because if he had been the cause of the fires, evidence of them should be found in the more elevated areas about the shores of the bog, but of this the account gives no information and we are left to infer that only the bog itself was involved. Furthermore, the features of deposition and the general character of the various strata, point with some force to the idea that we have here another example of a fire due to the spontaneous combustion of gases generated in the inferior strata where decomposition was evidently active.
Apart from its more strictly scientific aspects, the occurrence of such a conflagration as that which developed at Kittery Point gives a most singularly striking manifestation of a phenomenon which, as developed upon a very limited scale, has been a matter of common knowledge for a very long time, and has been woven into the folklore of various countries, where it has often played an important part in the life of the common people. Among English-speaking people the well-known 'corpse-candle,' 'Jack-o'-lantern,' and 'ignis fatuus' take a most conspicuous place in the superstitions of the less educated portions of the community, both in Europe and in America, even to the present day, although the scientific explanation has long since been accepted and understood.
Occidentals, however, by no means enjoy a monopoly of the romances and legends which may be gathered about the flickering flame of the elusive ignis fatuus. Very few countries have developed so rich a folk-lore as the Japanese, and the very fertile imaginations of her people have not failed to apply many weird explanations to an object capable of so many interpretations, sometimes investing their 'ghost-fire' with the same attributes that attach to our 'corpse-candle'; again attributing to their 'demon-light' the possession of singularly baleful influences; or in the 'badger-blaze,' 'fox-flame' and 'dragon-torch' finding a medium for the most varied witchery, sometimes comical, sometimes serious, and not always devoid of tragic results.
According to accounts by Brinkley, it is related of the 'badger-blaze' that it wanders in the Kawabe district of Settsu on rainy nights, and that uninitiated rustics, mistaking it for the glowing pipe of an ox-driver, hold commune with the badger, who is at all times a sociable fellow, and have even lit their own tobacco at his and puffed it in his company. Or again, at the base of the Ivatada hills, in the province of Omi, there lies a lake from whose margin on cloudy nights in early autumn a little ball of fire emerges. Creeping toward the foot of the mountains, it grows as it goes, sometimes swelling to a brilliant sphere three feet in diameter, sometimes not developing to more than a third of that size, but always when it rises to the height of a man's stature above ground, showing within its glow two faces, to which gradually the bosses of two naked wrestlers, struggling fiercely, attach themselves. It takes its way slowly and harmlessly to the recesses of the hills, but resents, with superhuman force, any attempt to interrupt its passage. Once a wrestler of unconquered fame waited at midnight for its coming, and sprang to grasp it as it passed through the mists. He was hurled to a distance of ten or twelve yards and barely escaped with his life.
The fox is an animal particularly addicted to assuming a great variety of shapes and disguises, often entering into and taking possession of people for evil purposes, or otherwise imitating various natural or artificial objects, thereby giving rise to great confusion or even distress, as witness the phantom train on the Tokaido railway some years since, which so terrified and confused an engineer as to nearly cause a disaster. Among other disguises of this animal is that of the so-called 'fox-flame,' which is assumed at night in dangerous and solitary places. The initiated, however, may readily overcome the spells of the 'fox-flame,' since all that is necessary is to join hands so as to leave a diamond-shaped opening between the crossed fingers. By blowing through this opening in the direction of the light, at the same time repeating a Buddhist formula, it is possible to extinguish the witch-fire at any distance.