HAGER'S THEORY. 207 



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, embrac- 

 ing 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. * 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 dip was continued to the well, and existed there (which is highly probable), it will be seen that the ascend- 

 ing 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. 



But from the fact that the valley, in which the frozen well is located, is surrounded on three sides with 

 solid beds of limestone, and has upon the other side immense deposits of clay sufficient to cut off all 

 communication with subterranean streams of water as well as extensive currents of air it will be seen 

 that no internal heat could be communicated to that valley by either of these agencies. 



The water in this basin is evidently cut off from all sources of supply, except such as falls upon the sur- 

 face, and percolates through the soil into the reservoir which was reached in digging the frozen well; hence 

 in a very dry time there may be a scarcity of water in it. 



The spring alluded to, about ten rods north of the well, will be more sensibly affected by drouth than the 

 well, for it is only the outlet from a comparatively small reservoir in a clay basin, and in a protracted dry 

 time will fail to furnish any water. 



Between the frozen earth found in digging the Brandon well, and the ice-beds that remain through the 

 summer in some of the abandoned portions of the Cheever Iron Mine, near Port Henry, in New York, 

 there seems to be a strong similarity of conditions. The ore veins in the latter, which dipped to the south- 

 east, at an angle of 40 to 60, were from ten to twenty feet in thickness, and have been removed except- 

 ing portions that were left to support the overhanging rock to the depth of one hundred and twenty-five 

 feet or more, and six or eight rods in length upon the vein. While the air is permitted to circulate through 

 the abandoned iron mine, and is impeded only by the occurrence of pillars that are left to support the roof 

 of the mine, so it also circulates with comparative freedom along the interstices of the bed of pebbles that 

 extends to the well, in a sloping direction from the gravel pit northwest of it. The dip of the bed of peb- 

 bles, and that of the orifice in the Cheever mine, are both from the northwest, so that the sun's rays, and 

 the attendant heat, can never directly enter in there. 



The water forming the ice-beds in the mine runs in from the surface, instead of being derived from 

 springs that break in from depths below, and the same is evidently true of the water found in the basin 

 around the frozen well. 



But had running streams of water passed through the valley in which the frozen well is located, or along 

 the bottom of that old iron mine, as is usual where water occurs in natural caverns, ice or frozen earth 

 would never have been found in either place, during midsummer. But as these nether regulators of tem- 

 perature are cut off, ice will continue to form in both during the freezing weather of winter, (the amount 

 depending upon the intensity of the cold) and be slowly wasted away the following summer. 



* 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 deg. Farenheit. 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 deg. while that of the one coated with clay was raised only to 56 deg. 



