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.
[PART V.]
LIST OF AUTHORS.