JOURNAL OF T H E

FRANKLIN INSTITUTE OF T H E STATE OF PENNSYLVANIA,

F O R T H E P R O M O T I O N O F T H E M E C H A N I C A R T S .

VOL. C X L I I I M A R C H , 1897 NO. 3

THE F r a n k l i n I n s t i t u t e is n o t r e s p o n s i b l e fo r t h e s t a t e - m e n t s a n d o p i n i o n s a d v a n c e d b y c o n t r i b u t o r s to t h e faurnM.

ICE C A V E S AND THE C A U S E S OF S U B T E R R A N E A N ICE .*

By EDWIN SWIFT BALCH, A.B., F .R.G.S . , t

Member of the Institute, ex-President of the Geographical Club of Philadelphia, etc.

I. DESCRIPTIVE AND EXPLANATORY.

Terminology.--The t e r m "ice c a v e " r e f e r s to a r o c k c a v e r n c o n t a i n i n g ice. I t does no t r e f e r to a ho l e or t unne l , cut b y t h e h a n d of m a n in to a g lac ie r , s u c h as t hose o n e sees a t G r i n d e l w a l d or C h a m o n i x . I m a k e t h i s s t a t e m e n t , because on m e n t i o n i n g ice c a v e s in c o n v e r s a t i o n I h a v e r e p e a t e d l y b e e n a s k e d w h e t h e r I m e a n t t h o s e t unne l s . T h e G e r m a n s use a t e r m s i m i l a r to ours , ~ishdhle, whi l e t h e French a n d S w i s s u se t h e w o r d g[aci~re, t h e f e m i n i n e of

* Entered according to Act of Congress, No~,ember 24, I896, by Edwin Swift Balch, in the Office of the Librarian of Congress, at Washington, D. C.

t A lecture delivered before the Franklin Institute, January 4, 1897.

Vot.. CXLIII , No. 855. i i

x62 Balch : [J. F. I.,

glacier, which they also apply to artificial ice houses, speak- ing of ice caves as glaci~res naturelles, and of ice houses as glaciates arliflcielles. The term glacikre seems to me the most accurate in use in any language , and, if it were not too late to do so, it would be an advan tage to use it, especial ly as we have adopted the te rm glacier f rom the same par t of the world. In my opinion, the te rm " i c e c a v e " should espe- cially apply to the hollows in the ice at the lower end of glaciers, whence the glacier waters make their exit. The Hon. George N. Curzon uses the term, apparen t ly in this sense, in a sketch publ i shed in the Geographical Journal in connect ion wi th his recent jou rney to the Pamirs , and in the account in the same publ ica t ion of the visi t of the English T ra in ing Squadron to Spitzbergen, in I895 , the te rm was applied to a na tu ra l tunne l found in a glacier.

Gladers.--Ice endur ing all the year round is found in three principal fo rms: glaciers, ice gorges and ice eaves. Glaciers are formed, to speak in general terms, f rom the win te r snows which have fallen f rom the skies, and, by their own weight , and me l t i ng and regelat ion, have accumula ted into a mass of ice, caus ing the phenomenon known as a glacier. Glaciers depend, therefore, pract ica l ly on the annua l snowfall and a low t empe ra tu r e for the i r existence.

Ice Gorges.--Ice gorges or ice gull ies show kinship to both glaciers and ice caves. T h e y occur in fissures or ravines, at an a l t i tude below the general snow line of the district, where the win te r snow is sufficiently protected from the sun to endure e i ther as snow or ice t h r o u g h the summer months. In some cages the surface ice and snow mel t s away, while u n d e r n e a t h boulders, at the bo t tom of fissures, ice still remains. For instance, I have found lumps of ice in King's Ravine , on Mount Adams, in the W h i t e Mounta ins , late in September, among tile b ig boulders which form such a try- ing pa th for the traveller. In such gullies, however, we have some th ing resembl ing r a the r min i a tu re glaciers than ice caves, in t ha t gul l ies receive the accret ion to their ice direct ly f rom the win te r snows. Some of the reasons for the i r endurance are similar, however, to those which apply to ice caves, in tha t they receive l i t t le if any of the direct

Mar., t897. ] Ice Caves and Subterranean [ce. I63

rays of the sun, and are also scarcely exposed to any ho t winds. I t is a lmost a se l f -evident propos i t ion t ha t the ice in such gul l ies is fo rmed in the same m a n n e r as the ice of glaciers, or the ice on ponds and rivers, by the cold of w in t e r and the m e l t i n g o f the snows ; and when ice is found remain- ing unde r boulders in such locali t ies, it is s imply t h a t the snow wa te r has run to the lowest level and there congealed. For conven ience these gull ies may be d iv ided in to two classes :

(I) T h e o rd ina ry open ravines , of which a fine example occurs in the S h a w a n g u n k Mounta ins in New York State .

(2) T h e ice unde r boulders , such as we find in King ' s Ravine.

Ice S h e e t s . - - A s u b t e r r a n e a n ice shee t covered wi th lava is repor ted f rom Moun t Etna, and p robab ly s imilar sheets also occur in Iceland. Sir Charles Lyel l accounts for the one on E t n a by the exp lana t ion tha t the re mus t have been a grea t snow bank in exis tence at the t ime of an e rup t ion of the volcano, and the lava s t r eam m u s t have flowed over the snow, which, in course of t ime, t u rned to solid ice un- derneath.

Wind-Holes . - - In m a n y par ts of the world we find wha t are known as cold-current caves, or b lowing holes, or wind-holes. These are pipes or holes, and in genera l t hey are found in more or less b roken l imes tone rocks. In mos t cases a cool air pours fo r th f rom t hem in summer , while the cold air pours into them in winter , the d r a u g h t be ing then reversed. In some cases, however , the opera t ion is said to take place in the opposi te way. De Saussure made an expe r imen t in connection wi th the first k ind of these holes, showing wha t is p robab ly the cause of the cool ing of the air current . He passed a cu r r en t of air t h r o u g h a glass tube, an inch in di- ameter, filled wi th moi s t ened stones, and found tha t the air current which en te red with a t e m p e r a t u r e of 22"5 ° C., came out with a t e m p e r a t u r e of I8"75°C, tha t is, wi th a loss of 3"75 ° of heat . As in l imes tone caverns there would gener- ally be mo i s tu re on some of the rock* surfaces on which air currents would pass, it is doubt less the evapora t ion f rom these sur faces which lowers the t e m p e r a t u r e of the air cur-

164 Balch ." [J. F. I..

rents. These wind-holes do not seem to necess i ta te the presence of ice. I have examined five of t hem myself , and in no case was there any ice ;¢isible. W h e t h e r there was any ice wi th in the m o u n t a i n I cannot, of course, say. At Seelisberg, on the Lake of Lucerne, the peasants have built l i t t le s tone houses over the rocks whence these currents issue, and use these houses for keep ing thei r provisions dur. ing the hea ts of summer . In all the wind-holes I have seen the cool air was pour ing out.

Ice Caves . - - Ice caves differ g rea t ly from ice gullies. Tile grea tes t d ivergence is t h a t there is a roof. Th i s means that the ice is formed direct ly in the cave itself, and is not, ex. cept perhaps near the entrance, solidified snow, bu t genuine sub te r ranean ice. The roof, while not a d m i t t i n g the winter snow, is, however, a protect ion aga ins t warm summer rains, and, of course, en t i re ly cuts off rad ia t ion from the sky. If, therefore, it keeps out some cold, it also acts as a protector aga ins t heat . I t m a y be not iced here tha t there is a strong resemblance be tween na tu ra l ice caves and artificial ice houses, a resemblance implied in their French appellation, glacikre, and, in fact, it is ha rd ly too much to look on ice caves as na tura l ice houses.

Kinds & Ice Caves.--Ice caves proper vary grea t ly in their positions, shapes and sizes. T h e y m a y be divided into three main kinds :

(i) Those at or near the base of cliffs, en te r ing directly into the m o u n t a i n wi th a down slope. Th i s class is found in l imes tone and in volcanic rocks. Examples : Tile Kolow- ratsh6hle, Dobsina, R o t h in tile Eifel.

(2) Those at or near the base of cliffs, where a long pas. sageway exists before the ice cave proper is reached. All I know of in this class are in l imes tone rock. Examples: Demenyf~ilva, the F rauenmauer .

(3) Those where a large pit opens into the ground, and the ice cave is found at the bo t tom opening into the pit. These are in l imestone. Example s : Chaux-les-Passavant and la Genolli~re.

Ice Caves witll Wind- t lo les . - - In two or three cases there are ice caves in connect ion wi th wind-holes ; t ha t is, there

Mar., x897.] [ce Caves and Subterranean Ice. 163

is first a la rge ice cave, at the rear of which is a fissure f rom which a d r a u g h t comes. One of these is near Cluses in Savoy, and Professor T h u r y s ta tes t ha t a long the line of the draught he found the ice in A u g u s t more mel ted than else- where in the cave. A n o t h e r of these ice caves wi th a wind- hole is in W a s h i n g t o n Te r r i t o ry , and is the la rges t ice cave so far r epo r t ed in the Un i t ed States .

Mines and Freezing 147ells.--Subterranean ice is also found in cer ta in places in connec t ion wi th man 's handiwork . I t is reported as fo rming in s o m e few mines in Europe and America. In some wells, also, in the New Eng land States, abnormal ly low t e m p e r a t u r e s ha~ee been observed, and for four or five m o n t h s of the win te r the surface of the wate r is frozen so th ick as to r ende r these wells useless.

Geographical Distribulion.--Ice caves p roper are found in various par t s of Europe, Asia and America , mos t ly in the smaller ranges or in the out l iers of the snowy ranges, gen- erally in l imes tone and occasional ly in basal t ic format ions . There are a good m a n y in the Jura , a few in Switzer land, a few in the I ta l ian Alps, a n u m b e r in the Eas te rn Alps, in Tyrol, S t e i e rmark and Carinthia . T h e r e are some in Hun- gary, several in Russ ia , one in Iceland, one on the Peak of Teneriffe, several in Siberia, one in Kondooz in Central Asia, one in Japan, and one in Korea . I have heard, so far, of twenty-nine places where sub t e r r anean ice is repor ted as occurring in Nor t h Amer ica , two of which are in Pennsyl- vania. Professors Schwalbe and F u g g e r give lists which mention over 20o places where s u b t e r r a n e a n ice is said to occur. However , these lists are not c la imed by the au thors themselves to be accura te .

Dimensions.--The dimens ions of ice caves vary great ly . Some are v e r y l a r g e , some very small. T h e measures of the cave at Dobsina, in the Carpathians , are g iven as fol lows: Height of roof above ice floor, to to i i me t e r s ; length , i2o meters ; brea'dth, 35 to 6o me te r s ; and surface abou t 4,644 square meters . T h e F r a u e n m a u e r Cave, in Eas te rn Tyrol , has an ice floor about 50 me te r s long by abou t 7 wide. T h e ice cave near Frain, on the contrary , is so small t ha t one can only crawl in some 2 or 3 meters , and this at the expense

I66 Balch : [J. F. |..

of soi l ing one's c lo th ing . In fact, ice caves va ry in size be- tween g rea t halls and small tunnels , in which one cannot s tand up s t ra igh t .

Sise o f Entrances . - -The en t r ances of ice caves va ry also g rea t ly as to the i r d imensions . As a rule t hey are small, t ha t is, a bou t the size of o rd ina ry door -ways ; bu t the en- t r ance to the Schafloeh, for ins tanee, is abou t io meters wide by 7 m e t e r s h igh, whi le the en t r ance to R o t h in the Eifel is not over I m e t e r each way.

Drainage . - -An i m p o r t a n t po in t in all ice eaves is the need of some ou t l e t for the surplus wa te r at the lowes t point of the cave, as o therwise the have would soon be en t i re ly filled. As the caves are a lways in e i the r porous or broken rocks, the necessa ry d ra inage takes place t h r o u g h the cracks and fissures in the rocks.

Forms of l c e . - - A l m o s t all the fo rms a s sumed by under- g round ice are d i f ferent f rom those vis ible in g lac ier or ice- berg. Th i s is only wha t should be expected , as the ice is fo rmed u nde r such d i f ferent condi t ions f rom those which ob ta in overground . T h e r e are no sdracs or crevasses such as one sees en route to the Grand Mulcts, for instance. The sharp angles and f rac tu res visible on glaciers are absent. A lmos t all the l ines are rounded. U n i q u e forms of subter- r anean ice are those p roduced by the drip f rom roof or sides, t ha t is, the forms of ice answer ing to the s ta lac t i tes and s t a l agmi te s of l imes tone caves. T h e y descend f rom the roof as icicles or r ise f rom the floor as cones or pyramids. Some t imes the icicles reach to the floor, and, connecting wi th it, become r egu l a r co lumns ; or some t imes columns issue f rom fissures in the sides in the shape of f rozen water- falls.

A t Dobs ina the s ta lac t i tes form g rand ice pillars. They are f rom 8 to I I m e t e r s in he ight , and f rom 2 to 3 meters in d iameter . In some of the caves, as a t Chauxdes-Passa- r a n t , the ice s t a l agmi tes take nea r ly the fo rm of cones. T h e r e are some seven or e igh t of them, the ta l les t of which is a t leas t 6 me te r s h igh, wi th a d i a m e t e r at the bo t tom of 5 or 6 meters . S o m e t i m e s these cones are hollow, as is the case in a g rand one at the Schafloch, some 6 mete rs or more in he igh t .

Mar.. 1897.] Ice 6ayes and Subterranean Ice. I6 7

T h e co lumns i s su ing f rom the sides of ice caves, for lack of a b e t t e r name, I ca l l f i s sure columns. T h e y seem always to issue f rom a crack in the rock, and then somet imes s t ream over the rock. Some t i mes t h e y spr ing out far enough f rom the rock to be qu i t e away from it. T h e s e fissure co lumns va ry f rom abou t 2 to 7 mete r s in he ight , and at the base a lmost a lways spread out fan-shaped. Schwalbe speaks of these co lumns as " s u b t e r r a n e a n glaciers ." Some are found in a lmost eve ry ice cave ; in one c a s e - - t h e Glaci~re de C h a p u i s - - t h e y form the special b e a u t y of the cave, as there are some seven or e igh t of them, each pe rhaps 5 or 6 me te r s high, and abou t I me t e r in d iameter , and spreading into fan-shape ~t the i r base.

T h e ice on the bo t t om of the caves of course takes its shape f rom the shape and angles of the floor of the caves. If the floor is level or nea r ly so, we find the ice in the shape of a shee t or floor. If the floor of the cave be s loping the ice will be found on more or less of a slope, somet imes becoming near ly or qu i te vert ical , as an ice s lope or ice wall, and d i s t an t ly r e sembl ing the por t ions of glaciers called an ice fall, wi th the g rea t difference, however , tha t there are no crevasses, not even t iny ones. "~ Holes we somet imes find, as at H a u t d 'Aviernoz , or runnels , a s a t the KolowratshShle , but these are en t i r e ly d is t inc t f rom crevasses. On these ice walls or ice slopes, the re is, in fact, no visible sign of any- th ing t ha t would lead to a suspicion of motion.

T h e holes, or runnels , j u s t re fe r red to are genera l ly found at the lowest po in t of the ice floors and are a lmost cer ta in ly cut out by the me l t ing water, to which they act as an exit . In fact, t h ey form the d ra inage sys tem in the ice. The holes are somet imes ve ry deep. A t H a u t d 'Aviernoz I looked down into one, which mus t have been many mete r s deep, and whose sides d i sappeared in darkness, no bo t tom being visible.

T h e drip p roduces also the exact opposi te of cones, in the shape of ice basins. T h e r e are two splendid ones in tile

No observer seems as yet to have looked for any evidences of motion in subterranean ice.

I68 t ?a lch : [ J. F. I ,

Kolowra t sh6h le , each cut ou t in the floor by an ex t ra s t rong dr ip f rom the roof at those spots. Such basins as these are not to be seen on glaciers.

Lakes and pools are to be found in ice caves. A t Chaux- l es -Passavant a pool of water , pe rhaps 30 cen t ime te r s in de p th and 4 or 5 me te r s in d iameter , lay at one place in A u g u s t on the ice floor. T h e whole cave was damp and the ice in places dec idedly Mushy, in fact, all the signs poin ted to a h e a v y thaw go ing on, and the re could be no doub t that the pool was the resu l t of this. In the GlaciSre de Chapuis, far unde rg r ound , the re are two ad jo in ing caverns, one filled wi th water , the o the r wi th ice.

Again, in at least one case, the Kolowra t sh6h le , a lake somet imes forms on the ice floor in the spr ing, f reezes over, and then runs off, l eav ing the marks of its passage in the shape of ice slabs r epos ing on the solid ice floor, as was the case on m y vis i t to this cave in the midd le of July, I895.

I th ink there is no d o u b t t ha t s u b t e r r a n e a n snow some- t imes occurs, p robab ly ear ly in the year. A case of the kind occur r ing in Centra l F rance has been no t iced in Monsieur Marte l ' s book, " L e s Abimes ," and m y b r o t h e r and I, in a vis i t to the Dobs ina cave ear ly in July, before m u c h thaw had set in, found in one spot of the cave a small sheet , per- haps 2 me te r s each way, of what , to look and touch, was ge nu ine snow. I have l i t t le doub t t ha t th is was fo rmed by the congeal ing, du r ing the i r fall, of drops of wa t e r f rom the roof.

T h e ice in caves is somet imes found in a form or struc- tu re which is, I bel ieve, of rare occur rence above ground. Th i s is when it occurs in the shape known as p r i sma t i c ice. If you b reak off a l ump f rom a co lumn or icicle you will somet imes not ice tha t it breaks into r egu la r prisms. I have seen this p r i smat ic ice a few t imes only. Browne speaks of it in his book as common. I am not sure tha t the p h e n o m e n o n is as ye t sa t i s fac tor i ly accoun ted for ; the only t h i n g I feel sure of is tha t it does not occur in ice of recent format ion . T h u r y speaks ,of it as a form which is due to some change in ice which has a l ready been fo rmed for some t ime.

Mar., i897. ] Ice Caves and Subterranean ice. 16 9

Color Effects.--The color effect of every ice cavern has a certain indiv idual i ty . At the Kolowra tsh6hle the ice is beaut i ful ly t ransparen t and of a pale ochre-greenish hue ; the l imes tone roeks are s t reaked wi th iron, and thus have a reddish hue, while, owing to the ent rance admi t t i ng p lenty of dayl ight , the effect is only semi-subterranean. At the Schafloch it is the exact opposite of th is ; the ice is so com- pletely away from day l igh t t ha t black is the p redomina t ing note, the iee i tself looking a dark gray. Again, at Chaux-les- Passavant p lenty of day l igh t is a d m i t t e d ; the rocks are a yellowish-brown, while the ice is whi te and blue. At Dob- sina, on the contrary, thanks to the electric l ight, whi te is the p redomina t ing note, in certain places and corners dulled into grayness by rock or shadow.

II. CAUSE OF TItE FORMATION ()F ICE.

The cause of the format ion of the ice is pract ical ly the most in t r ica te t h ing to unders t and and explain about ice caves. Numerous explanat ions have been offered on the subject , and m a n y theories formulated, some of which are absolutely untenable . The great cause, as far as I can see, is s imply the cold of winter, which re.forms anew each year the ice which has been des t royed by the hea t of the preced- ing summer . Before eIabora t ing the winter 's-cold theory, I wish to ment ion two or three theories which cannot possi- bly be accepted in connection with the facts.

Glacial Period.--A sugges t ion to account for the ice, which seems to occur to m a n y persons when they first hear of ice eaves, is tha t the ice is a r emnan t of the glacial period. This t h e o r y i s qui te untenable . The great cave of Chanx- les-Passavant was ent i re ly cleared of its ice in i727 by the Due de L~vi for the use of the A r m y of the Saone. In i743 the ice was formed again. At Szilize, every year, the ice has almost complete ly disappeared by November, and the cave is free; bu t in Apri l or May the floor is again covered with ice, and columns and icicles have formed on the roof and sides. A t La Genolli~re, the cgve is used by the people of the ne ighbor ing chalets t h rough the spr ing and early sum- mer to help in the operat ion of bu t t e r -making ; by the mid-

I70 BaIc'/t : [J. F. I.,

dle or the end of A u g u s t it has en t i re ly disappeared, bu t is found formed afresh every spring. Too m a n y examples of the complete me l t ing away of the ice every year can be cited to permi t any doubt on this poin t ; ice caves are not con- nected wi th a glacial period.

S a l t s . - - A n o t h e r favori te suggest ion, which cannot stand on an acquain tance wi th the facts, is t ha t there m u s t be salts in the rocks. An elaborate paper, g iv ing this as the true cause of the ice in Chaux-les-Passavant , was publ i shed in I712 , by M. de Billerez, in the proceedings of the French Academy. He s ta ted tha t the ear th in the immedia t e neigh- borhood, and especial ly above the roof of the grot to, was full of n i t rous or ammoniaca l salts, and he sugges ted that this salt was d is turbed by the hea t of summer , and mingled with the water which pene t ra ted by fissures into the cave. His observat ions have been absolu te ly disproved, and in no place have any such salts been found. Repea t ed experi- ments in l e t t ing lumps of cave ice mel t in m y m o u t h have convinced me personal ly t ha t in all cases the water is ex- ceedingly pure and sweet, and there can be no doubt that all, wha t m i g h t be called, chemical causes, m u s t be entirely e l iminated as possible cold'-producers. The very first notice ex tan t about ice caves, in the shape of a le t ter da ted 1586, of B~nigne Poissenot, a Paris lawyer, about Chaux-les-Passa- vant , speaks of the del iciousness of the ice water.

D r a u g h t s . - - T h e format ion of sub te r ranean ice is some- t imes - - in my opinion incor rec t ly - -as s igned to air currents or draughts . Cold caves fall into two divisions in regard to the movemen t s of a i r - -caves wi th and caves wi thout draughts . The first are ice caves proper ; the second vCind- holes or cold-current caves. Professor T h u r y seems to have been the first to call a t t en t ion to this fact, and he divided caves into stat ic and dynamic caves. The wind-current caves have complicated the u n d e r s t a n d i n g of the whole problem, as some observers have assumed tha t the draughts were the cause of the ice. I th ink the facts all t end to dis- prove any such idea, as very few of the observed wind-holes conta in any ice. In fact, it seems as if d r augh t s tend en- t i r e ly to melt, n o t t o form, ice. The air in ani6e cave isgener-

Mar., 1897. ] Ice Caves and Subterranean Ice. I71

ally a lmost still. I do not r emember ever feel ing any move- ment of air in an ice cave proper. In the double cave of Chapuis one cavern is filled wi th ice and the air is quiet, while the o ther is filled by a l i t t le lake, over which there is a d raught . The lake is, doubtless, the resul t of the draught , which p robab lymel t s the ice in summer, if, indeed, it does not prevent any f rom forming in winter. A t the en- trances of ice caves I have several t imes not iced faint move- ments of the cold air outwards, bu t this is never perceptible wi th in the body of caves. One cannot exact ly feel the air moving out, bu t by l igh t ing a cigar the smoke may be seen slowly moving outwards. A t the en t rance of the Kolow- ratshShle there was a fa in t ou tward current when I was there. The day was a hot one and qui te windless, and as the cold cave air met the hot outs ide air it formed a fa in t cloud or mis t jus t a t the m o u t h of the cavern.

Eva2oration and Atmosphere.mClosely connected wi th d raughts are the evaporat ion or expansion of the air in eaves, and b3( some persons these are assumed as the cause of the ice. From w h a t I have observed myself, I should say tha t the dryness or mois ture of the air is coincident with the state of freezing or t hawing of the cave. If you penet ra te into a large cave about the beg inn ing of June, when every- th ing is frozen up t ight , you will find no drips nor m u s h y ice ; the air will be re la t ively dry, and the sensat ion of cold not unpleasant . If you pene t ra te into tha t same cave about the end of A u g u s t you will find drips cofiaing from the roof, the ice soft, and the sensat ion of the air a penetra t ing, damp cold. T h u r y says tha t in the caves near Geneva he found in summer the air so sa tu ra ted wi th mois ture t ha t it could scarcely take up any more. In his observat ions wi th a psychrometer in the Grand Cave de Montarquis in Augus t , he found ~ of relat ive mois ture . A l t h o u g h from what I at present know, I am inclined to disbelieve in draughts , evaporation, or expansion caus ing ice to form, ye t I th ink there is need for a grea t deal more observat ion on this point.

Capillary T/teory.mAnother theory which has found some acceptance is the so-called capi l lary theory ; namely, tha t

172 Ba[c'k ." [J. F. I.,

bubbles of air, drawn into water, f lowing down th rough fis- sures in the rock, are l iable to a con t inua l ly increas ing pres- sure, compel l ing it to par t wi th l a ten t caloric, which is immed ia t e ly absorbed from the water on be ing l iberated in any cave or well or mine. There m a y be t ru th in this, and I have been assured tha t in some borings in Wes t e rn mines ice has been formed by pressure ; but if it applied to caves, I do not see why so m a n y thousands of caves contain no ice, and especially why ice caves are never known in hot coun- tries. If the theory were correct, we should, for instance, find ice in the eaves of Yucatan, described by Mr. Mercer. Still, this theory is held by some scientific observers. The H u n g a r i a n doctor at Dobsina told me he bel ieved in it, and Dr. Schwalbe, whose opinion is ent i t led to grea t respect on account of his m a n y observations, th inks t ha t the rocks in s u m m e r are a cooling factor, and, t ha t some cold comes out from them.*

S u m m e r [ce Formation T h e o r y . - - T h e theories jus t men- t ioned are advanced by we!l-educated persons, not necessa- ri ly scientists. '12.he na t ives and peasants in the neighbor- hood of ice caves genera l ly believe t ha t the ice of caves is formed in s u m m e r and mel ts in winter . This bel ief I have met wi th eve rywhe re - - i n the Eifel, Jura, Swiss Alps, Ty- rolese Alps and Carpathians . Peasan ts and guides will tell yon wi th absolute confidence : " T h e ho t te r the summer , the more ice there is." The hotel keeper at Eisenerz, near the F r a u e n m a u e r Cave, told me " m a n y people had broken their heads " in t ry ing to account for tha t cave freezing harder in A u g u s t than in May. This belief is founded principal ly on the fact tha t the nat ives scarcely ever go to an ice cave ex- cept when some tour is t takes t hem wi th him, and therefore they rarely see one in winter, and the i r opinion is, conse- quent ly , of no value. T h u r y tells a good story about this belief of the peasants . He vis i ted the Grand Cave de Mon- tarquis in midwinter . All the peasants told h im there

The capil lary theory was first advanced by Mr. N. M, Lowe, of Boston, aud publ ished in the Science 03server for April, I879. An admirable expo- sition of the theory by Mr. John Ritchie, Jr., was also publ ished in the same n u m b e r of the paper.

Mar., x897.] Ice Caz,cs and Subterranean fce. I73

would be no use going, as the re would be no ice in the cave. He t r ied to find even one peasan t who had been to the cave in winter , bu t could not. He then v is i ted it himself , and found it full of ha rd ice. On his r e t u rn he told the peasan ts of his discovery. T h e y were s t agge red at first. F ina l ly one e x c l a i m e d : " I t makes no d i f ference; in genu ine ice caves there is no ice in winter ."

Still, t he re is an appearance of t ru th in the peasants ' belief, and tha t is in the fact tha t the t e m p e r a t u r e s of ice cave;,, like tha t of o ther caves or t ha t of cellars, are colder in s u m m e r than the outs ide air, and are w a r m e r in win te r than the outs ide air. Possess ing ne i the r reason ing powers nor t he rmomete r s , the peasan ts s imply go a step fu r t he r and say t ha t the caves are cold in s u m m e r and ho t in winter . In o the r words, f rom sheer ignorance, out of a t rue fact t hey make nonsense.

T h e e x t r a o r d i n a r y t h i ng is t ha t any n u m b e r of w r i t e r s - - somet imes scientific m e n - - i n books and scientific papers, have accexpted this belief of the peasan ts and t r i ed to ac- count for it. An a t t e m p t at exp la in ing it da tes back as far as I686, in the Par is Igistoire de l'Academie Royale des Sciences. It :.s found in a G e r m a n book p r in t ed in 1689, then again in a F r e nc h scientific journa l in 1712. In the LoJzdon Philosophi- cal Transactions, in 1739, there is a long account in La t in about the cave of Szilize, in which the writer , a H u n g a r i a n savant, Mathias Be1, descr ibes how, as soon as the w a r m t h of spr ing comes, the cave begins to freeze, and, as the weather gets hot te r , f reezes the harder , until , in the dog days, icicles and co lumns grow with immense rapidi ty. But when the win te r comes the ice all mel t s away, the cave be- comes warm and pleasant , and the insects and the bats, and then the hares and foxes of the ne ighbo rhood come there in droves and live amicab ly t oge t he r dur ing the cold months . Several dozen wri ters in our cen tu ry accept and repea t these s t a t emen t s as the t ru th . Some t imes the s t a t emen t s are repeated with, somet imes wi thout , the hares and foxes, the latest r epe t i t ions occur r ing in ~86i, 1876, and 188i.

I47ir~.ter's Cold.--I now turn to the exp lana t ion which seems to me the t rue one, bo th because it is the s imple and

174 Ba lch : [ J. F. 1.,

obvious one, and because all the facts, as far as I have per- sonal ly observed, ent i re ly ta l ly wi th it. Th is is the theory tha t the cold air of win te r is the chief fac tor in p roduc ing the ice, and tha t it is t h rough its means tha t cer tain caves are conver ted into wha t are praet ica l ly na tura l ice houses. T h a t the cold of win te r p roduces the ice is h in ted a t b y Gollut in 1592 , by De Boz in i726. and b y Coss igny in I743 ; it is e l abora ted into s o m e t h i n g l i k e a theory b y Pr6vost in i789, and i ndependen t ly s u g g e s t e d b y T o w n s o n in I793 ; it is men t ioned by H u m b o l d t in 1814 and Delue in I822. W o r k e d at afresh and e labora ted into a t heo ry b y T h u r y in 186i and Browne in 1865, it has rece ived confi rmat ion in our own t ime by the work of Professor F u g g e r and Captain Trouil let .

All my own observa t ions have t ended more and more to make me bel ieve tha t the cold of win te r is the cause of the ice, and to make m y t h o u g h t clearer I will pu t it in the form of two proposi t ions. The first is :

The ice in caves is fo rmed ent i re ly b y the cold of win te r ; the hea t of s u m m e r tends to mel t it. Owing to the shel tered posi t ion of cave ice, however , the s u m m e r hea t reaches it wi th more difficulty than it reaches the snow and ice in the open, and cave ice, therefore, remains somet imes long af ter the ice in the su r round ing coun t ry has d isappeared.

The second is : T w o th ings are necessa ry for the format ion of ice. The

first is cold, the second is water . Therefore , to form ice in a cave, the cold air of win te r m u s t have access to it, and in some way wa te r mus t be suppl ied to it.

A l t i t u d e a n d L a t i t u d e s . - - T h e most impor t an t proof, to my mind, of the t ru th of these proposi t ions, is the fact tha t no ice cave tha t I have heard of, is found in any la t i tude or be low any a l t i tude where ice and snow does not form for par t of t h e y e a r in the su r round ing open eountry . None are repor ted from India or Africa, or, in fact, f rom any low-ly- ing places in tropical la t i tudes . T h e y are found mos t ly in middle la t i tudes , and only where du r ing par t of the year, at least, there is a cold season, tha t is, where, for some time, the t h e r m o m e t e r s tands be low f reezing point. Even in the middle la t i tudes they are in genera l at fairly h igh al t i tudes.

Mar., 1897 ] Ice Caves and Subterranean Ice. I75

The Schaf loeh is a t 1,78o m e t e r s ; Ske r i zo ra in T r a n s y l v a n i a at i,I27 m e t e r s ; D o b s i n a at i , i oo m e t e r s ; t he Glaci~re de Saint G e o r g e a t 1,2o8 me te r s . I t is t rue, t h e r e is one cave in the sub - t rop ica l l a t i t u d e of Tener i f fe , L a C u e v a de la Nieve ; b u t t h a t is at an a l t i t u d e of 3,3o0 mete r s , and w h e r e snow falls e v e r y y e a r in the o p e n on the Peak. U n l e s s s o m e cave is h e r e a f t e r d i s c o v e r e d in a r e g i o n w h e r e t he re is no winter , I do no t see h o w the i m p e r a t i v e n e c e s s i t y of t he presence of the cold a i r of w i n t e r for f o r m i n g the s u p p l y of ice can be c o n t r o v e r t e d .

Temperatures.--That t he cold air of w i n t e r is t he impor t - an t f a c to r in t he p r o d u c t i o n of cold s eems to m e also p r o v e d by the t h e r m o m e t r i c o b s e r v a t i o n s r e c o r d e d in v a r i o u s caves by d i f fe ren t obse rve r s . T h e y all tell t he s a m e tale, t h a t the t e m p e r a t u r e s v a r y w i t h t hose of the ou t s i de a i r ; t h a t t h e y are l owes t in w i n t e r a n d h i g h e s t in s u m m e r . H e r e are the resul ts of one y e a r ' s o b s e r v a t i o n a t D o b s i n a in deg ree s cen- t i g rade :

January, -- 4"2 July, -~- 2'~ February, -- 3'4 . August, + 3"8 March, -- 2'I September, -+- 2' 3 April, - - I'2 October, @ 0"2 May, -~- 0" 9 November, -- I'9 June, + I'5 December, -- 3'2

H e r e are a y e a r ' s o b s e r v a t i o n s a t F r a i n :

January, - - 5 July, 4- 3 to + 5 February, -- 5 to -- 2 August, -'-- 5 March, - - I to o September, .1_ 3 to -{- 6 April, o October, -{- 5 May, + 2 to + 5 November, -}- 5 June, -b 3 to 4- 6 December, o to -- 2

T h e s e f igures s eem to m e to p r o v e p r e t t y c o n c l u s i v e l y t h a t f r o m a b o u t the first of N o v e m b e r to the first of M a y we h a v e - - i n s i d e the ice c a v e s - - w i n t e r t e m p e r a t u r e s , t h a t is, t e m p e r a t u r e s be low f r e e z i n g p o i n t ; and f r o m a b o u t the first of M a y to t he first of N o v e m b e r we h a v e s u m m e r t e m p e r a - tures, t h a t is, t e m p e r a t u r e s a b o v e f r e e z i n g poin t .

Positions of Entrance and Body of, Caves.--A g r e a t a n d im- p o r t a n t f a c to r in p e r m i t t i n g the cold a i r to p e r m e a t e , a n d r e m a i n in, a cave, is the ac tua l f o r m a n d pos i t i on of the cave

I76 Ba[c] t : [J. F. l.,

a n d of t he e n t r a n c e . In all k n o w n cases , as f a r as I can learn , t he m a i n b o d y of an ice c ave is wel l b e l o w th e level of t he e n t r a n c e , a n d e v e n if t he ice c av e is s h e l t e r e d aga ins t t he wind, i t is no t s h e l t e r e d a g a i n s t t h e co ld a i r of winter . T h i s is h e a v y , and b y i ts o w n w e i g h t s inks wel l d o w n to the b o t t o m , f r e e z i n g up, in c o u r s e of t ime , all t h e m o i s t u r e tha t m a y dr ip f r o m t h e roo f or t h a t m a y c o m e in to t h e cave in t he s h a p e of m e l t e d s n o w or co ld w i n t e r ra in . T h e s u m m e r air, b e i n g w a r m and, t h e r e f o r e , l igh t , can o n l y e n t e r the cave m u c h m o r e s l owly to d i s l o d g e t h e w i n t e r a i r a n d de- s t r o y t he ice, a n d b e f o r e i t a c c o m p l i s h e s t h e l a t t e r , a n o t h e r w i n t e r ' s f r e eze r e v e r s e s once m o r e t h e cond i t i ons . T h i s ap- p l ies u n i v e r s a l l y to t he m a i n b o d y of t h e caves .

In all b u t two k n o w n cases t h e r e is a s t e a d y d r o p f rom the e n t r a n c e of an ice cave to t he ice. T h e s e e x c e p t i o n s are the P o s s e l t h 6 h l e and t h e F r a u e n m a u e r h 6 h l e , in wh ich y o u f irs t a s c e n d g r a d u a l l y a s h o r t d i s t a n c e b e f o r e t h e drop to t he m a i n ice beg ins . B o t h t h e s e cav es a re a t h i g h alti. t u d e s a n d wel l s h e l t e r e d . In t he F r a u e n m a u e r y o u h a v e to wa lk t h r o u g h a g a l l e r y for a b o u t 30 m e t e r s , a s c e n d i n g in t h a t d i s t a n c e p e r h a p s 3 m e t e r s , w h e n t h e s lope is sud- d e n l y r e v e r s e d and y o u t h e n h a v e a d o w n g rade . A t the h i g h e s t po in t , l as t Ju ly , I f o u n d q u i t e a l a r g e m a s s of ice, e n o u g h to fill, p e r h a p s , a coup l e of ice car t s . B u t as, in as. c e n d i n g to t he cave, I h a d c ro s sed t h e r e m a i n s of tw o snow a v a l a n c h e s , i t does no t s e e m v e r y r e m a r k a b l e t h a t b e t t e r s h e l t e r e d s u b t e r r a n e a n ice s h o u l d r e m a i n , e v e n if h i g h e r t h a n t he e n t r a n c e of the cave. I, t h e r e f o r e , s h o u l d n o t feel s u r p r i s e d at a n y t i m e to h e a r of an ice c av e b e i n g found w i t h t he b o d y of t he cave h i g h e r t h a n t h e e n t r a n c e ; bu t th i s w o u l d be e i t h e r a t a v e r y h i g h a l t i t u d e or in a v e r y h igh l a t i t ude . .×-

T h e p o s i t i o n of t he e n t r a n c e is v e r y i m p o r t a n t . In a lmos t all cases i t has a n o r t h e r l y e x p o s u r e , a n d is s h e l t e r e d ag a in s t

~÷ Since this paper has gone through the press, I have heard of a cave, "Amarnath," in the Himalayas,where the floor is said to slant upwards to the back wall. Two blocks of ice, which last through the year within the cave, are worshipped by the Hindus under the names of Siva and Ganesh, proba- bly as re-incarnations.

Mar., 1897. ] Ice Caves and Subterranean Ice. 177

entering winds. If these two condit ions do not exist the ice supply sure ly suffers. Somet imes the ent rance is more or less tortuous. In some eases it is protected by a fr inge of trees. Again, in one kind of ice cave there is first a great pit, a t the bo t tom and on one side of which we find the ice cave proper. In one case at least, the Geldloeh on the 0tscher, the ent rance is due south, and as a consequence the ice in the f ront of the cave, solid about the end of June, be- comes a lake about Augus t , and then cuts off access to the rear of the cave. In the case of the Kolowra tsh6hle the en- trance is badly shel tered aga ins t the wind, and this undoubt- edly affects the supply in summer , and causes more rapid melting there than in some other cases.

Time of Formation of [ce.--As al ready ment ioned, cold and water are the necessary requis i tes for the format ion of ice, and the t ime and me thod of format ion were approximate ly explained by Tiiury. His win te r excursions caused h im to accept as proved tha t part of the mounta ineers ' belief which holds tha t there is no ice formed in caves in winter. He says : " In winter the cold is not want ing, bu t if there is no spring emp ty ing into the cave, water is absent, and then no ice is formed. I t is in the spring, at the t ime of the first melting of the snows, t ha t the ice mus t be formed. Then water at o ° C. flows on the surface, and penet ra tes by the fissures of the rock and by the g rea t openings into the inte- rior of the chilled cavern, which receives besides the freez- ing n igh t air. The grot to then makes its year ly provision of ice, which could do no th ing more than d iminish dur ing the entire dura t ion of the hot season."

Dr. Te r l anday recent ly publ ished a paper about the Cave of Szilize, in which he asserts tha t ice does not form there in winter, bu t tha t the ice first forms in the win te r in the upper part of rock fissures, and tha t in the spring, at the t ime of an increase of tempera ture , this fissure ice is b rough t to the melting point by the successive en te r ing of hea t into the earth, and this water then arrives at the cave, .where it aids the format ion of icicles. This theor, y about fissure ice is probably in so far correct, t ha t the ice in the upper parts of fissures, near the surface of the ground, melts before the VOL. CXLIII. No. 855. i2

17 8 Tr imble : [ J. F. 1.,

ice in the lower parts of fissures. The drip would then na tu ra l ly run into the cave, and as long as the temperature of the cave was below freezing point would help to form cave ice.

But this theory does not take sufficiently into account surface thaws. Thu ry ' s theory is very good and t rue enough in m a n y respects, bu t it does not go far enough. The obser- vat ions of Professor Fugger , and especially those of Captain Troui l le t , make cer ta in the fact t ha t ice begins to form in a cave as soon as the t empera tu re of the cave has sunk below freezing point, whenever , f rom any cause, wa te r gets into the cave. Th i s will occur whenever there is a thaw outside at any t ime dur ing the course of the winter ; and it is proba- bly ent i re ly correct to assert tha t ice is formed intermit- t en t ly in caves all t h rough the win te r months .

In conclusion, I wish to say tha t I look on this paper as in the na tu re of a p r e l i m i n a r y report only. I have collected a grea t deal more in fo rmat ion about ice caves, which I' hope to publ ish before long. The whole subjec t is as ye t by no means exhausted , and fu r the r observat ions m a y br ing forth valuable results, and I wish I m i g h t now see American scientis ts give more a t t en t ion to the ice eaves of our own cont inent .

R E C E N T A D V A N C E S IN THE S T U D Y OF THE R E S I N S . ~

BY HENRY TRIMBLE.

I I I S T O R Y .

The earl iest knowledge of the resins was probably de- r ived from frankincense and m y r r h ; i t is possible, by cer. ta in pa in t ings on the walls of the anc ien t temple of Dayr el B~hri, in Upper Egypt , to recognize t ha t they were ira. por tan t articles of traffic seventeen centur ies before Christ; t hey were associated with such impor t an t commodit ies as

A b s t r a c t o f a l ec tu re de l i ve r ed before t h e F r a n k l i n I n s t i t u t e , Decem.

be r 4, I896.