Leeches 45 



thus securing additional protection. A heavy fall of snow also might 

 so blanket and protect the flats that the cold would be prevented from 

 penetrating to the desired depth and degree." 



(" Third Memorandum, September 14, 1919.") 



In accordance with the foregoing recommendation the headgate 

 at the lower dam of Carr Pond was opened at the end of November 

 and the new level attained on December 6, 1919, concerning which 

 Mr. W. A. Welch furnished the following data: At that time ice 

 three inches thick completely covered the lake. That same night 

 snow fell to a depth of two inches and on following days there were 

 many successive snowfalls, so that the ground and surface of the 

 lake were continuously covered. Drawing off of the water required 

 about three days, by which time the level had been lowered two feet 

 in the body of the lake and six feet in the lower extension below the 

 old dam. The temporary dam was then blown out and the water 

 level equalized. During the month of December the temperature had 

 been continuously cold and several times had fallen to zero. 



On December 30, I personally visited Carr Pond and noted the 

 prevailing conditions. Measurements were taken at the dam, on a 

 tree standing in the water at the extreme head of the lake, and on 

 the docks at Globe, Jacob Riis, and Kennedy camps. At each of 

 these points the level measured from the top of the solid ice was as 

 nearly as could be ascertained two feet nine inches below the normal 

 level of the preceding summer. Nearly all of the little bay or cove 

 near Mr. Herbert's shack, and considerable areas of that at Globe 

 Camp, together with a border of varying width around the shorelines, 

 were drained. All such places were covered with a layer of hard ice 

 about three (2.25 to 3.50) inches thick, evidently that existing at the 

 time the water was drawn off and which settled down as the water 

 level fell. On the lake generally the ice was from seven to eight and 

 one-half inches thick and on this lay a covering of snow from eight to 

 eleven inches thick, the latter at the cove near Herbert's shack and 

 vicinity. The air temperature in the shade just before noon of 

 December 30, a clear and calm day, was -4° C. (25° F.). 



Soundings made at various points around the lakeshore showed 

 that in most places the ground beneath the snow and ice covering 

 was frozen to a depth of only about two inches. Immediately beneath 

 this crust the temperature was -]- 1° C. (34° F.), at four inches 

 depth it was + 2° C. (36° F.) and at one foot + 4° C. (39° F.). 

 That the failure of the cold to penetrate deeper was due chiefly to 

 the protection of the snow blanket is indicated by the fact that the 

 ground under cover of the dock floor at Globe Camp, which was 

 free from snow, was frozen solidly to a depth of six and one- 

 quarter inches. At the drained cove near Herbert's conditions were 

 still less favorable. Here the snow was eleven inches deep, the ice 

 only two and one-quarter inches thick and the underlying mud every- 

 where unfrozen and very generally of a temperature of -|- 4° C. 

 (39° F.) even where in actual contact with the ice. An examination 

 of the lower surface of the ice made it evident that after settling 



