39 



wedges itself under the current-trade, as it were (for 

 atmospheric currents do not mingle, but stratify, the Hun- 

 toniau theory to the contrary notwithstanding), gradu- 

 ally descending to the sea-level. 



Of one summer high wind there is a partial report. 

 June 8th at 5 P.M., the gale arose on the mountain reach- 

 ing its height at 1 A.M., the 9th. At Bethlehem, N. H., 

 fifteen miles west (1,800 feet above the level of the sea), 

 there was a gentle breeze till 11 p. M., the 8th, but from 

 that hour to 5 A. M., the 9th, the wind was high. At Beth- 

 lehem a cool, windy day followed, but on the mountain 

 it was nearly calm and mild. Nor did it reach its high- 

 est point at Hanover till it had abated on Mount Wash- 

 ington. 



CLOUDS. 



It is obvious that the higher upper currents, especially 

 of cirrus, which often floats at an elevation of 21,000 

 feet, Avill not present any very marked difference at the 

 altitude of a little more than a mile. Generally it is dur- 

 ing the transition stage into cirro-stratus or cirro-cumulus 

 that we find this elevation advantageous. It becomes 

 decidedly so when we would study the lower cloud-forms 

 or observe the condensation of an approaching storm. 

 As is well known, the higher upper current of cirrus is a 

 westerly one, that it has a movement from west, or south 

 of west, eastward. Passing into any sub-form the course 

 may be from any point between S. S. W. and N. N. W. 

 The lower currents of cumuli, which are rare in winter, 

 and the stratus run low, seldom rising to the level of the 

 summit. The stratus of winter is often extended over 

 an area of several hundred square miles, and rarely lias a 

 greater average thickness, in the vicinity of the moun- 

 tain, and probably not elsewhere, than 1,000 feet. 



It is doubtful if, in this latitude, it ever exceeds 3,000 



