318 ANNUAL OF SCIENTIFIC DISCOVERY. 



of the air at the surface. In winter the cold is much more intense than -in 

 summer. 



The subject presented two leading inquiries. 1st. When, and by what 

 agency, was the congelation produced so deep beneath the surface? ~M. 15y 

 what means is the frost preserved from external and internal heat? In 

 reply, there were two suggestions to be made. 1st. These frozen deposits 

 may have been produced during the glacial period that accompanied the 

 formation of the drift. 



This suggestion was dwelt upon at length, and it was contended that a 

 frozen deposit of any past period might be indefinitely preserved. Experi- 

 ments had been made which showed that even a thin layer of clay was a 

 powerful resistant to heat. The clay on the surface at Brandon would ex- 

 clude the external heat, while the gravelly strata, free from sand, would act 

 as a tunnel to carry the ascending internal heat to the surface, and it would 

 not, therefore, reach the frozen deposit. The arrangement at Brandon was 

 in many respects similar to the most approved ice-houses. But, after all, 

 he was not sure that this was the true theory. 



There was another theory. 2d. We maintain that, in porous depositions, 

 especially when interstratified with those nearly impervious to air, ice may 

 be formed in large quantities at any depth, and remain unmelted for a great 

 length of time. This position was elaborated, showing by diagrams that 

 when a porous mass was overlaid by clay, the heat of summer could have 

 but little effect upon it. It had been stated, and it had not been disproved, 

 that there were subterranean currents of air. At Owego, the candle-flame 

 was deflected at the depth ^f thirty feet. 



Upon the whole, though it is possible that the Brandon deposit is a rem- 

 nant of a glacial period, he looked with more favor upon the supposition 

 that it Avas the result of operations now going on, produced by currents of 

 air through the porous deposit. 



In a discussion of these phenomena at a recent meeting of the Boston 

 Society of Natural History, Prof. W. B. Rogers observed, " that it was im- 

 portant to consider the mean temperature of the place, in explaining the 

 phenomena of frozen wells. The mean annual temperature of Brandon is 

 only 45 F. ; of the winter, 20 ; of the spring, 40 ; giving for the winter 

 and spring a temperature of 30, or two degrees less than the freezing-point 

 of water. In fact, at about the depth of thirty or forty feet, a reversal of 

 the seasons takes place, so slow is the progression of temperature down- 

 ward. The access of external air is also important. The temperature of 

 the air in winter at the bottom of this well must be very IOAV. The lateral 

 perforation of this low temperature ought to be traced; the law of progress 

 of temperature from the surface downward, in this special locality, should 

 be ascertained. So that the question of explanation becomes very com- 

 plicated." 



In connection with this subject, some interesting observations have been 

 made by Mr. J. W. Andrews, of Albany, on the temperature of Lake Dun- 

 more, a considerable body of water, situated about eight miles in a north- 

 easterly direction from the well at Brandon. The average depth of water 

 in this lake, Mr. Andrews found, by frequent soundings, to be between fifty 

 and sixty feet, and the maximum, accurately found, being seventy-five feet. 

 At this last point, a maximum and minimum registering thermometer was 

 let down, and gave the following curious results : 



