SOME OPINIONS ABOUT GLACIÈRES.

« 268 »
« 269 »

SOME OPINIONS ABOUT GLACIÈRES.

Benigne Poissenot, in 1586, hinted that the cold of winter produced the ice at Chaux-les-Passavant.[69]

Reichard Strein and Christoph Schallenberger visited the caves on the Ötscher in 1591.[70]

Gollut, in 1592, suggested the cold of winter as the cause of the ice at Chaux-les-Passavant.[71]

In the Histoire de l’AcadÉmie Royale des Sciences, 1686, Tome II., pages 2, 3, there is an account, with no author’s name, of Chaux-les-Passavant. The memoir states that in winter the cave is filled with thick vapors and that after some trees were cut down near the entrance, the ice was less abundant than formerly: that people come for ice with carts and mules, but that the ice does not become exhausted, for one day of great heat forms more ice than could be carried away in eight days in carts and wagons: and that when a fog forms in the cave, there is assuredly rain the following day, and that the peasants in the neighborhood consult this curious “almanac” to know the weather which is coming.

Freiherr Valvasor, in 1689, wrote about some of the glaciÈres of the Krain.[72]

Behrens, in 1703, thought it was colder in summer than in winter in the caves near Questenberg in the Harz.

M. de Billerez, in 1712, writes that at Chaux-les-Passavant it is really colder in summer than in winter; and that the ice is harder than river ice, and this he thinks is due to the presence of a nitrous or ammoniacal salt, which he says he found in the rocks.

M. de Boz made four trips to Chaux-les-Passavant on the 15th of May and 8th of November, 1725; and the 8th of March and 20th of August, 1726. His memoir says that his observations tend to disprove those of M. de Billerez, and that “the cause for the great cold, which is less great in summer, although always remaining, is quite natural.” He cites as causes for the ice the exposure to the north-north-east; the rock portal sheltering the entrance, and all the forest covering the surrounding lands; and adds that some veracious persons told him that since some of the big trees above the grotto had been cut down there was less ice than before. He found no traces of salt, nor any springs, and that the water supply came from the rains and melted snows filtering through the ground.

In 1739, Matthias Bel published his curious account of Szilize.[73]

J. N. Nagel, a Vienna mathematician, visited the Ötscher in 1747. He concluded that the ice was made in winter and preserved in summer as in an ice house.

M. de Cossigny wrote, in 1750, about Chaux-les-Passavant. He made a plan of the cave and took many observations in April, August and October, and concluded that the interior condition of the cave does not change noticeably from winter to summer, no matter what the external conditions of temperature may be; that what people say of greater cold in summer, vanishes before actual experience and that, as a state of freezing reigns more or less continuously in the cave, it is not surprising if the ice accumulates. Apparently he was the first to notice and insist on the necessity of drainage to the cave through cracks in the rocks. He also made a series of observations disproving those of M. de Billerez, as to the presence of any kinds of salts in the rocks or ice.

Hacquet, in 1778, thought that the ice in the cave at Lazhna-gora formed in winter, but he also thought that there must undoubtedly be some salt in the water. He says he found ice in the cave in the spring, and that his companion, a priest, had never found any in winter. He therefore concluded that by that time it had all melted.

Romain Joly, in 1779, claims to have visited Chaux-les-Passavant on the 19th of September (year not given). His account seems largely borrowed from the one in the Histoire de l’AcadÉmie Royale des Sciences, in 1686. He says: “This ice is formed by the drops of water which fall from the roof, and which freeze because of the chill of the cave. In the winter there is no ice, but running water.” He says nothing, however, about the ice forming in summer.

The Citoyen Girod-Chantrans visited Chaux-les-Passavant in August, 1783, and reached the conclusion, from all he saw and heard, that the cave did not freeze in summer nor thaw in winter, and that it was really a natural ice house. He was aided by the notes of a neighboring physician, Dr. Oudot, who had made observations in the cave, and among others, had placed stakes of wood, on the 8th of January, 1779, in the heads of the columns he had found in the cave; and on the 22d of February, 1780, had found these stakes completely covered with ice, forming columns 30 centimeters in diameter.

Hablizl, in 1788, wrote that the ice in the cave near Karassoubazar formed in the spring by the snows which melt, run into the cave, and refreeze. He also thought that there was less ice there in the fall than in the spring, that it diminishes in July and August, and that the idea, current in the neighborhood, of the formation of ice in summer, is a mistake.

Professor Pierre PrÉvost, in 1789, gave an accurate explanation of the formation of the ice in Chaux-les-Passavant. He says: "Weighing carefully the local circumstances, one discovers in truth a few causes of permanent cold. But these causes seem rather suited to keep up a great freshness or to diminish the heat of summer, than to produce a cold such as that which reigns in the cavern. First of all, big trees throw shade over the entrance; it is, I was told, forbidden under severe penalties to cut down any of them, for fear of depriving the grotto of a necessary shelter. In the second place, this entrance is situated almost due north, leaning a little to the east, which is the coolest exposure one can choose, and the one most suited to help the effect of the icy winds which blow from that quarter. Finally the slope is steep and the grotto deep and covered with a thick vault. These three conditions united constitute, as it seems to me, a very good ice house; by which I mean a reservoir fit to preserve during the summer, the ice which may bank up in winter.

“But how does this ice bank up? One knows that the outside waters above form on the roof, during the winter, long drops and stalactites of ice. These icicles, which hang down and increase constantly by the drip from the same source which formed them, fall at last, carried away by their own weight, and form so many centres, around which freeze the waters with which the floor of the grotto is always inundated. At the same time, the blowing of the north wind accumulates snow at the base of the slope, which is uncovered in part and exposed above to all the vicissitudes of the weather. Thus during the winter is formed an irregular heap of ice and snow, which the first heats of spring begin to make run, but which the heats of summer cannot finish dissolving. The winter following has therefore even more facility to augment the mass of these ice pyramids, which have resisted until the fall. And if men did not work at diminishing it, it might happen that it would fill the entire cavern at last to a great height.

“I am therefore strongly inclined to think that the process of nature is here precisely similar to that of art; that without any especial cause of cold, the natural glaciÈre of BesanÇon conserves in the moderate temperature of deep caverns, the heaps of snow and ice which the winds and the outside waters accumulate there during the winter; and that the melting of these snows and of these accumulated ices forms little by little the ice floor, scattered over with blocks and pyramids, which one observes there during the summer.”

Horace BÉnÉdict de Saussure, the great Swiss scientist and mountaineer, in 1796, published a number of observations about cold current caves in various parts of the Alps. He found that in summer the air blows outward at the lower end, and that in winter it draws inward. His explanation is that in summer the colder air in the tube is heavier than the outside air and displaces it by gravity; while in winter the rupture takes place in the other direction, since the column within the tube is warmer than the outside air and therefore is pushed upwards by the heavy air flowing in. He concludes that evaporation due to the air passing internally over moist rocks suffices to explain the phenomenon of low temperatures and that such caves have a rather lower temperature in the Alps than in Italy owing to the greater natural cold of the Swiss lake region. An experiment of his is worth mentioning. He passed a current of air through a glass tube, 2.5 centimeters in diameter, filled with moistened stones, and found that the air current which entered with a temperature of 22.5° came out with a temperature of 18.75°, that is with a loss of 3.75° of heat.

Robert Townson, LL.D., in 1797, published an account, perhaps the first in English, of a glaciÈre cave. He says of Szilize: "Ice I truly found here in abundance, and it was mid-summer, but in a state of thaw; the bed of ice, which covered the floor of the cavern was thinly covered with water and everything announced a thaw. I had no need to use my thermometer: however I placed it in the ice and it fell to 0° of RÉaumur: I then wiped it and placed it in a niche in the rock, at the furthest part of the cavern, a yard above the ice and here it remained near an hour: when I returned I found it at 0°. * * * Everything therefore, ice, water and atmosphere in the neighborhood had the same temperature, and that was the temperature of melting ice: 0° RÉaumur.

“When then is the ice which is found here, and in such quantities that this cavern serves the few opulent nobility in the neighborhood as an ice house, formed? Surely in winter, though not by the first frost, not so soon as ice is formed in the open air. No doubt, from the little communication this cavern has with the atmosphere, it will be but little and slowly affected by the change. Should therefore, Mr. Bel, or any of his friends, have come here to verify the common report at the commencement of a severe frost, when the whole country was covered with ice and snow, they might still have found nothing here but water, or the ice of the preceding winter in a state of thaw, and the cavern relatively warm; and likewise, should they have visited it in a warm spring, which had succeeded to a severe winter, they might have found nothing here but frost and ice; and even the fresh melted snow, percolating through the roof of this cavern, might again have been congealed to ice. I observed frequently in Germany in the severe winter of 1794-5, on a sudden thaw, that the walls of churches and other public buildings, on the outside were white and covered with a hoar frost, and the windows on the same side covered with a rime.”

Dr. Franz Sartori, in 1809, was a strong believer in the summer ice theory, and wrote of the flies and the gnats, the bats and the owls, and the foxes and the hares coming to Szilize to winter.

Alexander von Humboldt, in 1814, says about the Cueva del Hielo on the Peak of Teneriffe that so much snow and ice are stored up in winter that the summer heat cannot melt it all, and also adds that permanent snow in caves must depend more on the amount of winter snow, and the freedom from hot winds, than on the absolute altitude of the cave.

Dewey, in 1819, thought that the ice in the Snow Glen at Williamstown was a winter formation.

Professor M. A. Pictet visited Saint-Georges, Le Brezon and Montarquis and in 1822 endeavored to prove that they are cold current caves and that the ice in them is due entirely to draughts causing evaporation. He believed in the theory of the ice forming in summer more than in winter and that it could not be the residue of a winter deposit. He therefore argued that it must be due to descending currents of air which he thought would be most energetic in summer; that they would become at least as low as the mean annual temperature of the place and be still further cooled by evaporation. The strange thing about his theories is that he does not seem to have personally observed any draughts either at Saint-Georges or Le Brezon, but the fact that the ice was evidently not an accumulation of winter snow led him to try to reconcile what he had himself seen with de Saussure’s theories about windholes.

Jean AndrÉ Deluc in 1822 published a paper discussing the theories of MM. de Cossigny, PrÉvost and Pictet. Deluc had never visited a glaciÈre himself, but he explains clearly the impossibility of Professor Pictet’s cold current theory, on the simple ground that Professor Pictet himself did not find any cold currents. He takes up Professor PrÉvost’s theories warmly; using also the manuscript notes of Mons. Colladon who had visited the Grand Cave de Montarquis. Deluc says: “that the winter’s cold penetrates into these caves, freezes the water which collects there and that the ice thus formed has not the time to melt during the following summer.” He says further: “It seems that in the three glaciÈres with which we have been occupied there is a flat or rather hollow bottom, where the waters can form a more or less deep pond, and whence they therefore cannot flow away; it is there they flow in winter; and as these are shut in places where the air cannot circulate, the heats of summer can only penetrate very feebly. The ice once formed in such cavities, only melts slowly; for one knows that ice in melting, absorbs 60° of heat; and where find this heat in an air always very cold and nearly still? During a great cold, the ice forms with great promptness, while it melts with much slowness, even when the temperature of the air is several degrees above zero; what must then not be this slowness when the temperature of the interior air only rises in summer one degree above freezing point. It would need several summers to melt this ice if it did not reform each winter.”

C. A. Lee, in 1825, wrote that the ice in the Wolfshollow near Salisbury was a winter formation.

G. Poulett Scrope, in 1826, accepted as the truth the statement that the cave of Roth was filled with ice in summer, but that it was warm during the winter. In 1827, he explained the presence of ice at Pontgibaud as follows: “The water is apparently frozen by means of the powerful evaporation produced by a current of very dry air issuing from some long fissures or arched galleries which communicate with the cave, and owing its dryness to the absorbent qualities of the lava through which it passes.”

F. Reich, in 1834, thought that there were two possible causes which might produce subterranean ice: 1, the difference in specific gravity between warm and cold air; 2, evaporation. He thought the cold air a sufficient cause in most caves, but he considered that evaporation also played a part not infrequently.

Professor Silliman, in 1839, gave the first hint, in the negative, about compressed air as a cause for subterranean ice. He said about Owego that if one could suppose that compressed gases or a compressed atmosphere were escaping from the water or near it, this would indicate a source of cold, but that as there is no indication of this in the water, the explanation is unavailable.

Professor A. Pleischl wrote in 1841 that he was told that ice formed on the Pleschiwetz and on the Steinberge in summer. Continuing, he says: "The author is therefore, as well as for other reasons, of the opinion, that the ice is not remaining winter ice, but a summer formation, and one formed by the cold of evaporation. * * * The basalt is, as a thick stone, a good conductor for the heat, and takes up therefore easily the sun’s warmth, but parts with it easily to other neighboring bodies. In the hollows, between the basalt blocks, is found, as I already mentioned, rotting moss, which forms a spongy mass, which is wet through with water. The basalt heated by the sun’s rays now causes a part of the water in the spongy mass to vaporize; for this evaporation the water needs heat, which it withdraws from the neighboring bodies and in part from water, and makes the water so cold, that it freezes into ice, as, under the bell of an air pump—Nature therefore makes here a physical experiment on the largest scale."

Much stress appears to have been laid on the paper of Professor Pleischl by Professor Krauss and one or two others. The weak point in it is that Pleischl did not see the ice form in summer, but was only, as usual, told that it did so. There is nothing in the facts given to show that the places mentioned are different from any other taluses, where ice does not form as the result of heat.

Mr. C. B. Hayden, in 1843, wrote about the Ice Mountain in Virginia, and held that the porous nature of the rocks makes them poor conductors of heat, and that the mountain is a huge sandstone refrigerator.

Dr. S. Pearl Lathrop, in 1844, wrote of the Ice Bed at Wallingford, Vermont, as a great natural refrigerator.

Sir Roderick Impey Murchison wrote in 1845 about the salt mine and freezing cave of Illetzkaya-Zatschita. He visited them during a hot August, and was assured that the cold within is greatest when the external air is hottest and driest; that the fall of rain and a moist atmosphere produce some diminution in the cold of the cave and that on the setting in of winter the ice disappears entirely. He accepted these statements evidently only in a half hearted way, submitting them to Sir John Herschel, who tried to explain them, in case they were true, of which Herschel was likewise doubtful. Murchison at first thought that the ice was due to the underlying bed of salt, but soon recognized that this explanation could not be correct. He also rejected Herschel’s “heat and cold wave” theory. Shortly after this he came across Pictet’s memoir, and on the strength of it concluded that the ice in Illetzkaya-Zatschita could not be the residue of a winter deposit, but must be due to descending currents of air; to the previously wet and damp roof affording a passage to water; and to the excessive dryness of the external air of these southern steppes contributing powerfully to the refrigerating effects of evaporation.

Professor Arnold Guyot, in 1856, said that the well at Owego admitted large quantities of snow which melts, but not readily, because it is not accessible to the sun. It therefore goes through the same process as glaciers, of partly melting and refreezing; and we have the formation of a glacier without movement.

Professor W. B. Rogers, in 1856, held that the well at Owego became the recipient of the coldest air of the neighborhood, and the temperature remained abnormal because the bad conducting power of the materials of the well retained the cold.

Professor D. Olmstead, in 1856, held about Owego that cold air exists in the interior of the earth which may have found a ventilating shaft in the well.

Professor Petruzzi, in 1857, considered the following requirements necessary for a glaciÈre: A high altitude above the sea; a decided drop into the interior of the mountain; absence of all draught; protection against all warm and moist winds, therefore the opening to north and east. He also says about the glaciÈre on the Pograca: that it is in shadow; that the thick forest round the mouth keeps the temperature down; that it begins to freeze below when it does above; that the cold remains there into the spring; and that the water from rain or other sources, which flows into the cave, must freeze there, and the ice form in greater quantities than the heat of summer can melt away.

Mr. Albert D. Hager wrote in 1859: "The question now arises, why it was that such a congealed mass of earth was found in Brandon at the time the frozen well was dug. My opinion is, that the bad conducting property of the solids surrounding it, the absence of ascending currents of heated air, and of subterranean streams of water in this particular locality favored such a result; and that the bad conducting property of clay, as well as that of the porous gravel associated with it, taken in connection with the highly inclined porous strata, and the disposition of heated air to rise, and the cold air to remain below, contribute to produce in the earth, at this place, a mammoth refrigerator, embracing essentially the same principle as that involved in the justly celebrated refrigerator known as 'Winship’s Patent.'

“Clay is not only nearly impervious to air and water, but it is one of the worst conductors of heat in nature. (Note.—To test the question whether clay was a poor conductor of heat or not, I took two basins of equal size, and in one put a coating of clay one-half inch thick, into which I put water of a temperature of 52° Fahrenheit. Into the other dish, which was clean, I put water of the same temperature, and subjected the two basins to equal amounts of heat; and in five minutes the water in the clean dish indicated a temperature of 70° while that of the one coated with clay was raised only to 56°.) If we can rely upon the statements of those who dug out the frozen earth, it rested upon a stratum of clay that lay upon the bed of pebbles in which the water was found, for it was described as being a very sticky kind of hard pan.

“This being the case, if the water contained in the pebbly mass had a temperature above the freezing point, the heat would be but imperfectly transmitted to the frost, through the clay, provided there was no other way for its escape. But we have seen that the stratum of clay that overlays the bed of pebbles in the side of the gravel pit was not horizontal, but inclined towards the well at an angle of 25°. Now if this drip was continued to the well, and existed there (which is highly probable), it will be seen that the ascending current of heated air, in the pebbly bed, would be checked upon meeting the overlying barrier of clay and be deflected out of its upward course. The tendency of heated air is to rise, hence it would continue its course along the under side of the clay, through the interstices in the bed of pebbles, till it found a place of escape at the surface, which in this case may have been at the gravel pit before named.”

Professor Edward Hitchcock wrote in 1861: "The presence of a mass of frozen gravel deep beneath the surface in Brandon, was first made known by digging a well in it in the autumn of 1858. * * * The gravel, also, rises into occasional knolls and ridges. In short, it is just such a region of sand and gravel as may be seen in many places along the western side of the Green Mountains; and indeed, all over New England. It is what we call modified drift, and lies above genuine drift, having been the result of aqueous agency subsequent to the drift period. * * * The well was stoned up late in the autumn of 1858, and during the winter, ice formed upon the water in one night, two inches thick. It continued to freeze till April; after which no ice was formed on the surface, but we can testify that as late as June 25th, the stones of the well for four or five feet above the surface of the water were mostly coated with ice; nay, it had not wholly disappeared July 14th. The temperature of the water was only one degree of Fahrenheit above freezing point. The ice did however disappear in the autumn but was formed again (how early we did not learn) in the winter, and so thick too that it was necessary to send some one into the well to break it. We visited the well August 18th, 1860, and found the temperature 42°. Yet only the week previous ice was seen upon the stones, and we were even told by one of the family, that a piece of ice had been drawn up the day before in the bucket. * * * These frozen deposits may have been produced during the glacial period that accompanied the formation of drift, and continued far down into the subsequent epochs of modified drift. * * * But in all the excavations both gravel and clay occur: and how almost impervious to heat must such a coating 20 feet thick, be! It would not, however, completely protect the subjacent mass from solar heat. But there is another agency still more powerful for this end, namely, evaporation, which we think has operated here, as we shall more fully describe further on; and we think that these two agencies, namely, non-conduction and evaporation, may have preserved this frozen deposit for a very long period, from exterior influences."

Professor Thury in 1861 says about Saint-Georges: "Such is the rÉsumÉ, concise but exact, of the results of our winter excursion. They furnish proof to the fact generally borne witness to by the mountaineers, that ice does not form in winter in the interior of caverns. But if this is so, it is for a very simple reason: two things are necessary for the formation of ice: cold and water. In winter, the cold is not wanting: but if there is no spring opening in the cave, the water is absent, and then no ice forms.

“It is in the spring, at the time of the first melting of the snows, that the ice must form. Then water at 0° pours over the surface, and penetrates by the fissures of the rock and by the large openings into the chilled cavern, which is also receiving the freezing air of the nights. The grotto then makes its annual provision of ice, which after this could only diminish little by little during the whole duration of the warm season.”

Professor Thury writes about the Grand Cave de Montarquis: “Here it must be when water and cold meet, that is autumn and especially spring, the time of the first melting of the snows.”

“During the winter * * * the colder, heavier air comes to freeze the water of the grotto, and chill the ice and the wall of rock.”

“During the summer, the radiation of the vaults and the proper heat of the ground only melt a small quantity of ice because this absorbs much heat to pass into a liquid state.”

“The heat of the air is entirely used to melt the ice; it does not therefore manifest itself as sensible heat.”

“The contact of the ice ready to melt, plays in a certain way, towards the air a little warmer than itself, the rÔle of an extremely absorbing body, or one which has an excessive caloric conductibility.”

“Here the formation of the ice could not possibly be attributed to the cold caused by evaporation. The psychrometer indicated ninety-two per cent, of relative humidity: the atmosphere of the grotto was therefore almost saturated with evaporation of water, and the maximum of cold caused by evaporation was not over half a degree centigrade.”

About prismatic ice and a hollow pyramid, he says: “The prismatic (arÉolaire) structure is produced later on in the ice, by a new and particular arrangement of the molecules of the already solidified water. Therefore the recent stalactites are never crystallized.”

“In the beginning of the hot season, the atmospheric temperature of the grotto rises slowly. Inferior to zero by some tenths of a degree, it produces first on the surface, in the stalactites, the prismatic structure. The temperature continues to rise, the central portions of the stalactites, still composed of ordinary ice, liquefy, and if the melting water finds some issue, either by accidental openings left between some prisms, or by the extremity of the stalactite or by some point of its surface which had escaped the action of the regular crystallization; by this opening the water escapes, and the tubular stalactite has been formed.”

“The column was composed of a very special ice, perfectly dry, perfectly homogeneous, translucid and whose appearance could only be compared to that of the most beautiful porcelain. I am inclined to believe that we had under our eyes a special molecular state of congealed water. This state would be produced under the influence of a constant temperature of a certain degree (Note—perhaps not far from 4°—the actual temperature of the grotto) long prolonged. These causes can be realized more completely in glaciÈres than anywheres else.”

The Reverend George Forrest Browne, published in 1865, Ice Caves in France and Switzerland, one of the most delightful books of travel ever written, on account of the scientific accuracy and the humor of the author. He visited La GenolliÈre, Saint-Georges, Saint-Livres, Chaux-les-Passavant, MonthÉzy, Arc-sous-Çicon, the Schafloch, Haut-d’Aviernoz, which he calls Grand Anu, Chapuis, and Font-d’Urle. He says: "The view which Deluc adopted was one which I have myself independently formed. * * * The heavy cold air of winter sinks down into the glaciÈres, and the lighter warm air of summer cannot on ordinary principles of gravitation dislodge it, so that heat is very slowly spread in the caves; and even when some amount of heat does reach the ice, the latter melts but slowly, for ice absorbs 60° C. of heat in melting; and thus, when ice is once formed, it becomes a material guarantee for the permanence of cold in the cave. For this explanation to hold good it is necessary that the level at which the ice is formed should be below the level of the entrance to the cave; otherwise the mere weight of the cold air would cause it to leave its prison as soon as the spring warmth arrived. In every single case that has come under my observation, this condition has been emphatically fulfilled. It is necessary, also, that the cave should be protected from direct radiation, as the gravitation of cold air has nothing to do with resistance to that powerful means of introducing heat. This condition, also, is fulfilled by nature in all the glaciÈres I have visited, excepting that of S. Georges; and there art has replaced the protection formerly afforded by the thick trees which grew over the hole of entrance. The effect of the second hole in the roof of this glaciÈre is to destroy all the ice which is within range of the sun. A third and very necessary condition is, that the wind should not be allowed access to the cave; for if it were, it would infallibly bring in heated air, in spite of the specific weight of the cold air stored within. It will be understood from my description of such glaciÈres as that of the Grand Anu, of MonthÉzy, and the lower glaciÈre of the PrÉ de S. Livres, how completely sheltered from all winds the entrances to those caves are. There can be no doubt, too, that the large surfaces which are available for evaporation have much to do with maintaining a somewhat lower temperature than the mean temperature of the place where the cave occurs."

Browne noticed prismatic ice several times. He says of it: "M. Thury suggests also, as a possibility, what I have found to be the case by frequent observations, that the prismatic ice has greater power of resisting heat than ordinary ice. * * * A Frenchman who was present in the room in which the Chemical Section of the British Association met at Bath, and heard a paper which I read there on this prismatic structure, suggested that it was probably something akin to the rhomboidal form assumed by dried mud; and I have since been struck by the great resemblance to it, as far as the surface goes, which the pits of mud left by the coprolite workers near Cambridge offer, of course on a very large scale. This led me to suppose that the intense dryness which would naturally be the result of the action of some weeks or months of great cold upon subterranean ice might be one of the causes of its assuming this form, and the observations at Jena would rather confirm than contradict this view: competent authorities, however, seem inclined to believe that warmth, and not cold, is the producing cause."

Mr. Browne found a hollow cone at La GenolliÈre, for which he accounted as follows: "In the loftier part of the cave * * * ninety six drops of water in a minute splashed on to a small stone immediately under the main fissure. This stone was in the centre of a considerable area of the floor which was clear of ice. * * * I found that the edge of the ice round this clear area was much thicker than the rest of the ice on the floor, and was evidently the remains of the swelling pedestal of the column. * * * When the melted snows of spring send down to the cave, through the fissures of the rock, an abundance of water at a very low temperature and the cave itself is stored with the winter’s cold, these thicker rings of ice catch first the descending water, and so a circular wall, naturally conical, is formed around the area of stones; the remaining water either running off through the interstices, or forming a floor of ice of less thickness, which yields to the next summer’s drops. In the course of time, this conical wall rises, narrowing always, till a dome-like roof is at length formed and thenceforth the column is solid." From what I have observed myself, this explanation seems to fairly meet the facts.

Professor T. G. Bonney, in 1868, was inclined to believe that there was some connection between glaciÈres and a glacial period.

Mr. W. R. Raymond, in 1869, concluded from his own observations about the lava cave in Washington: that the cold air of winter freezes up the percolating waters from the surface, layer upon layer, solid from the bottom, and the accumulated ice thaws slowly in summer, being retarded by the covering which keeps out the direct rays of the sun, and by the fact that the melting ice at one end of the cave, through which the summer draught enters, itself refrigerates the air and maintains a freezing temperature at the other end.

Dr. C. A. White, in 1870, says of the cavern at Decorah: “The formation of the ice is probably due to the rapid evaporation of the moisture of the earth and rocks, caused by the heat of the summer sun upon the outer wall of the fissure and valley side. This outer wall is from ten to twenty feet in thickness where the ice was seen to be most abundant. The water for its production seems to be supplied by slow exudation from the inner wall of the cave.”

Dr. Krenner, in 1874, wrote of DÓbsina as “a natural ice cellar of giant dimensions, whose ice masses formed in winter, the summer does not succeed in melting.”

Professor W. Boyd Dawkins wrote in 1874: “The apparent anomaly that one only out of a group of caves exposed to the same temperature should be a glaciÈre, may be explained by the fact that these conditions [those formulated by the Rev. G. F. Browne] are found in combination but rarely, and if one were absent there would be no accumulation of perpetual ice. It is very probable that the store of cold laid up in these caves, as in an ice house, has been ultimately derived from the great refrigeration of climate in Europe in the Glacial Period.”

Mr. Theodore Kirchhoff examined the lava caves in the State of Washington and in 1876 wrote that he considered that the ice in the smaller ones were simply remains of the winter’s cold. He thought that the ice in the large cave where there is a draught could not be accounted for in the same way, so he concluded that the ice must be due to the draught.

Mr. N. M. Lowe, in 1879, proposed the Compressed Air or Capillary theory[74] about the Cave at Decorah.

Mr. John Ritchie, Jr., in 1879, gave an exceedingly clear exposition of the theory in the same journal.

Mr. Aden S. Benedict, in 1881, published his observations about Decorah. He found that there was no water falling in the cave to compress the air, that there was no water falling near enough to be heard, nor any aperture giving vent to cold air in the cave. He thought that the cold of winter cools the sides of the cave several degrees below freezing point and that these rocks are so far underground that it would take a long season of hot weather to raise this temperature to the melting point of ice. In the spring the water percolates through the soil and drips on to the yet freezing rocks; on which it freezes and remains until the heat of summer penetrates to a sufficient depth to melt it away. The rocks once raised above 0° remain so until the following winter and consequently if there are heavy autumn rains there is water on the rocks but no ice. Mr. Benedict concluded that there was nothing more mysterious about Decorah than the fact that if you drop water on a cold stone it will freeze.

Professor Friederich Umlauft in 1883 wrote about glaciÈres "that as moreover they were generally protected against warm winds and strong draughts and as their entrances look towards the north or east, there is consequently more ice formed under these conditions in winter than can melt away in summer. Other ice grottoes however show the remarkable characteristic, that it is warm in them in winter, in the summer on the contrary it becomes so cold that all the dripping water freezes. They are found near snow clefts and gorges; when in the hot summer months the snow melts, then the cold which has become free presses down the temperature in the cave so much that the water freezes into ice. Such grottoes are in Austria at * * * Frauenmauer, * * * Brandstein, * * * Teplitz, * * * Scilize, * * * Dobschauer."

Herr KÖrber in 1885 wrote about the Schafloch, that the stored-up winter’s cold stands out as permanent adversary of the higher temperature of the earth. The thermometer proved this by its action at the end of the cave in a rock cleft, which is warmer than the rest of the cave. In September Herr KÖrber found the masses of ice less and the stalagmites smaller than in January, especially a column which in January had become a stately mountain of transparent ice.

Professor Eberhard Fugger of Salzburg, has studied the caves of the Untersberg carefully, having paid over eighty visits to them. He classifies freezing caverns into the following types, according to their position and their shape:

According to position: 1, open caves, that is those whose entrance is free on a rock wall; 2, pit caves, where the entrance is at the bottom of a pit; 3, pit caves, where the pit is covered and the opening is in the roof.

According to shape: 1, sackhÖhlen or chamber caverns, into which one enters immediately at the entrance; 2, ganghÖhlen, or passage caves terminating in a chamber; 3, rÖhrenhÖhlen, or passage caves where the passages continue further than the chamber.

He is a strong advocate of the winter’s cold theory. He says: “The ice of caves is formed by the cold of winter, and remains despite the heat of summer, as through local circumstances the quantity of heat brought to the ice is not great enough to melt it by the time when ice and snow in the open at the same altitude have already disappeared.”

“In order that ice may form in a cave in winter, two factors are necessary. There must be water present in some form or other, and in some way the outside cold air must be able to sink into the cave.”

“When the bottom of a cave is below the entrance, the outside cold winter air sinks into the cave from its weight, when the temperature of the cave air is higher than that of the outside air; and it will remain there during the warmer weather, as the warm outside air on account of its lighter weight cannot drive out the cold heavy cave air.”

“The most important factor for the formation of ice is the drip water. The more drip flows into a cave during the cold season, the more ice is formed; the more drip, on the contrary, flows into the cave during the warm season, the more ice is destroyed.”

“The warmth, which the roof of the cave gives out, is also a cause which helps to melt the ice, and a cause in fact which works the harder, the higher the temperature of the roof and the dirtier the ice floor.”

“If direct rays of the sun penetrate a cave, they scarcely warm up the air which they traverse, but they raise the temperature of the floor or of the walls, which they touch. They are therefore a very important factor, which may bring about the melting of the ice.”

“The snow slope at the mouth of a cave offers some protection against the rays of the sun, especially if it is no longer white, but covered with all sorts of dirt.”

“The larger the mass of ice, the longer is its duration.” “A certain thickness to the roof is of importance in preserving the ice. If it is less than 8 meters, then it is well if it is covered with outside vegetation.”

I entirely agree with these dicta of Professor Fugger.

In 1893, Fugger writes: "The peculiar readings of temperature, which I made in August 1877, in the KolowratshÖhle, namely on the 13th at 12 M., 0.5°, on the 15th at 4 P. M., 0.35°, on the 23d at 10 A. M., 0.12°, on the 26th at 10 A. M., 0.17°, and on the 30th at 2.15 P. M., -0.10°, I think I can attribute to the workings of the winds. In the observations themselves there could scarce be an error. All five observations were made at the same place, with the same thermometer, after at least half an hour’s exposure. In the time from the 13th to the 30th of August, the temperature minimum in the town of Salzburg, was 12°; before the 30th were several cloudless nights. During the whole of August scarcely any but southeast and northwest winds were blowing. The KolowratshÖhle opens in a rock wall to the east; the above named winds therefore affected during the entire month the entrance to the cave and may have produced a lively evaporation in the cave, through a sort of sucking up of the cave air, and thus have created the rather decided cooling off of 0.6° within seventeen days."

This statement, coming from Professor Fugger, deserves particular attention, because it would go to show: first, that the air in the KolowratshÖhle, a sackhÖhle with only one entrance, is only apparently stagnant in summer and not really so; and second, that evaporation may act to a limited extent in a cavern where there is almost no running water.

Captain Trouillet, in 1885, published a paper about Chaux-les-Passavant. He found that when it was colder inside than outside, the internal air was nearly cut off from the outside; when it was coldest outside there was a lively disturbance. He called these two classes pÉriodes fermÉes and pÉriodes ouvertes. He says: “The duration of a closed period is measured then on the curves [of a maximum and minimum thermometer] of the interior temperatures, between a minimum and the following maximum; that of an open period is between a minimum and the preceding maximum. One can thus count from the 25th November to the 31st December 25 open periods of a total duration of 200 hours or 8 times 24 hours: which gives for each a duration of 7-1/2 hours. The shortest lasted 2 hours and the longest 16 hours. During the same interval, the closed periods numbered 26, making a total duration of about 28 days; the longest, which lasted from the 3d to the 8th December, was 126 hours long.”

Trouillet also says: “From the 23d to the 30th December, the grotto was completely isolated from the external air, and yet during three consecutive nights, the interior had three marked chills. Such is the phenomenon whose cause can only lay, in our opinion, in the introduction of the dry air driven to the cave by the winds between north and east. This air on entering comes in contact with the ice and the humid roof of the cave; it saturates itself in producing a formation of vapors, and therefrom a consumption of heat which may be considerable.”

There are some discrepancies in this last paragraph which must be noted, for the reason that Trouillet’s observations are so valuable. He does not mention having seen the vapors himself, in fact the production of these vapors seems only an inference. Nor is it easy to understand how the grotto could be “completely isolated from the external air” if the phenomenon lay “in the introduction of the dry air driven to the cave by the winds north and east.”

Dr. B. Schwalbe, in 1886, wrote that “all my observations point to the fact that the rock is the cooling factor in summer, and that the cold goes out from it.” He says also that "when I saw for the first time the little cave of Roth, which was filled with fairly numerous ice formations, it was precisely the smallness of the volume of air and the strange appearance of the ice which made the simple cold air theory seen insufficient, nor could I later, by widening the theory and observing the localities from the basis of DeLuc’s theory, accept it. It always seemed by all my observations that in the rock there must be a lasting source of cold. There must be a cause present, which prevents the rapid warming of the cave wall through the temperature of the ground, which also keeps the stone cool in summer and induces the main ice formation in the spring." He also hints that Mr. Lowe’s compressed air theory may be the correct one. Dr. Schwalbe’s work, Über EishÖhlen und EislÖcher, is one of the four or five most important contributions to glaciÈre literature, and his opinion is entitled to great respect on account of his many observations.

Professor Israel C. Russell wrote in 1890, about the ice beds on the Yukon: “It is thought by some observers, to be an inheritance from a former period of extreme cold; but under existing climatic conditions, when ice forms beneath a layer of moss, it is preserved during the short summer, and may increase as it does on the tundras, to an astonishing thickness.”

In 1897, Professor Russell says: "It is not probable that all the subsoil ice of northern regions has been formed in one way. Along the flood plains and on the deltas of rivers where layers of clear ice are interbedded with sheets of frozen gravel and vegetable matter, as is frequently the case, it seems evident that the growth of the deposit is due, in some instances, to the flooding of previously frozen layers, and the freezing and subsequent burial of the sediment thus added to their surfaces. When spring freshets spread out sheets of dÉbris over the flood plain of a river, as frequently happens when streams in high latitudes flow northward, the previously frozen soil and the ice of ponds and swamps may be buried and indefinitely preserved." “There is still another process by which frozen subsoil may be formed in high latitudes: this is, the effects of the cold during the long winters are not counteracted by the heat during the short summers. Under the conditions now prevailing in northern Alaska, where the mean annual temperature is below 32° Fahrenheit, the frozen layer tends to increase the thickness from year to year just as the depth of frozen soil in more temperate latitudes may increase from month to month during the winter season. During the short northern summers, especially where the ground is moss covered, melting only extends a few inches below the surface.”

Mons. E. A. Martel, in 1892, wrote of the Creux-PercÉ: “I incline only, as in all the pits which narrow at the bottom (avens À rÉtrÉcissement) to attribute the chilling to the fall of the cold air of winter and to its non-renewal in summer.” And at page 564 of Les Abimes he says: "One knows that evaporation is an active cause of cooling; therefore it is always cooler in caves near the drips of water. * * * I have positively noted this influence of evaporation near the drips of Tabourel (8° instead of 9.5°), of Dargilan, of the Cerna Jama, and in abysses with double mouths where there were strong draughts (Rabanel, Biau, Fosse-Mobile, etc.)." In December, 1897, Mons. Martel writes: “In short, the action of the winter’s cold is the real cause accepted by * * * and recently confirmed by Fugger, Trouillet and Martel.” And also: “It is probable that this influence [evaporation] is only real at rather high altitudes; this is at least what seems the result of the studies of the caves of Naye (1700 to 1900 meters) begun by Professor Dutoit.”

In 1899, Mons. Martel gave an account of the GlaciÈre de Naye. In this paper, he abandons definitely fossil ice, salts and the capillary theory as possible causes of underground ice. He considers that there are four causes: 1, shape of the cavity; 2, free access of snow in winter; 3, high altitude; 4, evaporation due to wind currents. The last two causes he thinks are not necessarily always present. For instance he considers that, at the Creux-PercÉ, and at Chaux-les-Passavant, the ice is due especially to the sack or hour-glass shape of these hollows where the summer air cannot get in on account of its lightness. At the GlaciÈre de Naye, which is a big windhole, situated at an altitude of 1750 to 1820 meters, Mons. Martel thinks that the ice is formed by the snow and cold of winter, but that its preservation is assured by the evaporation caused by the action of the windhole.

Dr. Terlanday, in 1893, asserted that ice does not form in Szilize in winter, and that the ice first forms in the winter in the upper part of rock fissures and that in the spring, at the time of an increase of temperature, this fissure ice is brought to the melting point by the successive entering of heat into the earth and that it then arrives at the cave, where it aids the formation of icicles. This theory about fissure ice is probably in so far correct, that the ice in the upper parts of fissures, near the surface of the ground, melts before the ice in the lower parts of fissures. The drip would then naturally run into the cave and, as long as the temperature of the cave was low, help to form cave ice.

Dr. Hans Lohmann, in 1895, published some valuable notes about several glaciÈres. While considering the cold of winter as the main cause of the ice, he thought evaporation a secondary cause of cold. He says: "That the cold from evaporation bears its share in cooling a cave, will not be denied. * * * The air saturated with aqueous vapor makes one think of constant evaporation. The aqueous vapor spreads itself by diffusion throughout the entire cave, and if the outside air is driest, goes to that. Through this, more ice and water can always be vaporized, and to the warming elements there is furnished a cooling one. If dry winds get into the cave, then must evaporation be very lively and the chilling especially strong. Through this cause alone can be explained the remarkably low temperature of +6.3° in the new part of the Garischen Stollen, in contrast to the temperature of +7.9° in the old part. The strong draught in the last drew out through its suction the damp air of the new adit, so that there had to be a strong evaporation."

Dr. Lohmann gives some exhaustive notes about prismatic ice. He found it a product of the fall months. He thinks all the observations show that “the beginning of all prismatic formation in the ice may be looked for in the changes of temperature in the cave at the time of the formation of the ice. These cause the everywhere recognized splitting, vertically to the outer surface. The further development hangs, as shown by Hagenbach and Emden, on the attempt of the neighboring cells, to join into larger unities. The increase of the larger crystals is finally prevented by the melting out of the openings between the separate crystals. Through this may be explained the difference in the prismatic ice in different parts of the same cave.”

Regierungsrath Franz Kraus, in 1895, wrote a short essay on glaciÈres in HÖhlenkunde. He seems to have seen but few glaciÈres himself, and considers the scientific side of the question by no means solved as yet. He says: “The last word will not be spoken by the geographers and the Alpine climbers * * * but by the physicists, in whose field both questions really belong. Only then, when the physical circumstances of the formation of the ice in glaciÈres have been so thoroughly understood, that under the same circumstances it may be possible to build artificial glaciÈres, only then could one say: the glaciÈre question is definitely settled. The best proof is always experiment.”

He lays down several dicta which he says are universally recognized, among which is this: “2. The ice formations in the dÉbris heaps of basaltic mountains are summer ice formations. The evaporation of the infiltration water is recognized on all sides as the cause of this ice.” I differ in opinion from Herr Kraus about this matter, and think that, on the contrary, every proof shows that the ice of basaltic taluses is not a summer formation and is not due to evaporation.

Herr Kraus also says: “The EishÖhlen resemble so little the WindrÖhren, that for these a proper name is quite correct. Just as one cannot draw a sharp line between EinstÜrzschlÜnden and EinstÜrzdolinen, so one cannot draw a sharp line between eishÖhlen and windrÖhren. A stagnation of cave air does not exist, and no cave student would pretend to say it existed. The circulation of air may in certain caves take place almost entirely through the mouth and it then depends largely on the shape of the latter; in other caves are crevices and erosion holes, which allow a circulation of air. Again in other caves air may come through the floor into the cave, as is proved by certain places always remaining free from ice.”

He also says: "The formation of dripstone is also diminished about thick roofs, when the cracks are too broad to permit a slow dripping process. In caves with sufficient air movements, that is ventilation, the dripstone formation takes place faster than in those in which the air is only slowly renewed. Also in such caves, in which the air is strongly filled with moisture, the dripstone formation process is materially hindered. Therefore in water caves and in eishÖhlen one finds only rarely dripstone formations, and these mainly of poor appearance. But in all cases the carbonic acid of the infiltration water plays an important part."

In 1896, a Western newspaper published the following explanation about the presence of ice in the cave at Elkinsville, Indiana; and it shows how the idea—long since exploded—of the ice being due to chemical causes, serenely bobs up on the discovery of a new cave: “Some have advanced the theory that the air is forced through under passages of the earth with such pressure as to make the strange formation; some have attributed the cause to an underlying bed of alkali, whose chemical change to a gaseous form has produced the phenomenon. Others have thought that the interior heat of the earth, acting upon the iron pyrites, or fool’s gold, which largely abounds in this country, is the true source of this unparalleled discovery. Still others think that the sudden expansion of the carbonic acid gas given off by the heated limestone, which is also common in this country, could have easily produced the ice. But thus far the theories are nothing more than speculation, and further than the fact that the ice cave exists, and is, indeed, a remarkable phenomenon, none has been able to further determine.”

In 1896, Dr. A. Cvijic wrote that the cold air of winter is the source of cold in the glaciÈres of Servia. The mountains have so little water that the shepherds constantly take the ice out in summer for their own use.

In 1897, numerous newspapers, among others, the Philadelphia Press of August 1st, romanced as follows about the cave at Decorah: “In the summer its temperature is far below freezing. * * * From some unknown source in the impenetrable rear of the cave comes a blast of cold air as chill as from the Arctic region. In the winter the temperature of the cave is like summer. * * * We followed the winding passage in and out for more than 1000 feet. * * * I took out the thermometer and laid it upon the floor of the cavern for three minutes. When I took it up again I found that the mercury had fallen to 5 degrees below zero.”

“What is it that causes this phenomenon? Scientific men are said to have visited the cave within the last day or two who have declared that it had in some manner a subterranean connection with the polar regions, and that the cold air from the North coming in contact with the warm moist atmosphere from outside converted the vapor into water on the walls of the cavern where it straightway congealed. * * * It seems to me possible after thinking the matter over carefully, that in some mysterious manner the same influences that work the changes in climate in the Arctic and Antarctic regions are operating in this cave. It is a well-known fact that in the regions referred to the seasons are the reverse of what they are here.”

Mr. W. S. Auchincloss writes in 1897: “We also notice the working of the same principle during summer days. The hottest part does not occur at the noon hour—when the sun is on the meridian—but several hours later in the afternoon. In this case the accessions of heat arrive more rapidly than radiation is able to carry off. Radiation, however, keeps on apace, and, at last attaining the mastery, temperature falls. Ice caves furnish another example of the gradual procession in the seasons.”

Mr. Alois F. Kovarik writes about Decorah in 1898 that "the length of duration of the ice in the cave during the spring and summer depends upon the quantity of cold stored up in the walls and this again upon the coldness and the length of coldness of the previous winter. If the winter be severe and long, the walls will store up a great supply of cold for the gradual dissipation in the spring and summer and consequently the phenomenon of the ice in the ice chambers will last longer. Last winter, with an exception of the fore part of December, was quite mild. As a result, the ice began to disappear with the latter part of June, and totally disappeared by the end of July. * * * The time of the lowest temperature in the cave depends upon how soon the cold spells of the winter begin; for the sooner the walls begin to freeze to a greater depth, the sooner have they stored up the greatest amount of cold. * * * February 28th, 1898, when the walls contained the greatest amount of cold, there was no ice in the cave, for the reason that no water made appearance. Could water have appeared, no doubt a great amount of ice would have formed; but as the conditions are, the water has to come from the ground outside, and this being frozen at the time, water could not in any natural way appear. If in early spring, sufficiently warm days should come to melt the snow and open the ground, the water not taken up by the ground would flow and seep through crevices into the cave and ice consequently would appear early. Somewhat such conditions prevailed this year, for warm days appeared quite early in the spring. If per contra the ground does not open until in April, as was the case in 1895 and 1896, the appearance of the ice is consequently delayed. * * * Naturally this opening [the entrance] was small, but to give easier entrance, it was enlarged to its present size. * * * If the entrance had been left a small opening, as it naturally was, it is my belief that the temperature of the interior of the cave would be lower in summer than it is, and the ice would not disappear as soon as it does."

Mr. Robert Butler, of San JosÉ, Cal., investigated the question of cold air draughts coming from the glaciÈre cave and from the freezing shaft he examined in Montana. He wrote to me, in 1898, that he found that one notices or imagines to notice a draught of air, especially on hot days. Rapidly walking into the cave from the hot air without to the rapidly cooling air within produces the same nervous sensations as though one were to remain stationary and the air were to pass by from the warm to the colder portions. A distance of twelve meters finds a difference in temperature of fifteen degrees Centigrade. Twelve meters can be walked quickly, so quickly that the nerves cannot become accustomed gradually to the change of temperature. The rapidly cooling air does actually produce the sensation of cool air passing by one’s face. It produces somewhat the same sensation as the evaporation of ether on the surface of the body. Mr. Butler satisfied himself that as far as he had observed all the seemingly peculiar conditions and places where the ice has been found do not indicate any other causes when carefully investigated than those of the seasons of the year, and that the ice was formed by no other cause than the natural cold of winter.

Professor Cranmer, in 1899, added some important contributions to our knowledge of freezing caverns. All his work goes to prove the winter’s cold theory, but he has brought out some new details. He found warm and cold periods in the Tablerloch during the winter months. The coldest air sank to the bottom and the air in the cave stratified itself according to its specific gravity and its temperature. During a cold period, the outside air sank into the cave only to the air stratum, whose temperature, from the preceding warm period, was as much higher as that of the outer air, as this had become warmer in sinking to that stratum. The air which enters falls down the slope and displaces an equal volume of air which streams out under the roof.

Water will sometimes drip through a crack in winter until that crack freezes up, when the water may then find some other crack to drip through; at this second place a stalagmite may then grow, while at the first place the stalagmite may stop growing and even begin to diminish from evaporation.

Ice begins to form, whenever water gets into a cave, if the cave temperature is below 0°; ice begins to melt as soon as the temperature is over 0°.

Professor Cranmer found that occasionally small quantities of ice form in caves in the summer months: this was in mountain caves, where there was snow on the mountains and the temperature of the nights at least, had sunk below freezing point: in fact when the conditions were those of the winter months.

---