OP ARTS AND SCIENCES. 271 



crop at the Hogback and the present well, in order to discover the 

 extent of the frozen ground ; and this we shall do now at the close of 

 the summer months, when the heat shall have penetrated as far as it is 

 likely to go. 



Several hypotheses have been proposed, to account for the exist- 

 ence of this bed of frozen gravel ; such as its being, perhaps, a fossil 

 glacier of a period of intense cold, during the drift epoch ; or that the 

 cold air of the winter months may have penetrated through even a 

 pebble-bed; or that the longer continuance of winter cold may have 

 caused freezing of the gravel-bed, and that the heat of our short sum- 

 mers has not been able to reach the ice to melt it. 



The committee as yet adopt no conclusions, but are collecting the 

 elements for a solution of the problem, and hope in due time to 

 arrive at trustworthy results. They have procured from Mr. David 

 Buckland, of Brandon, (one of the Smithsonian observers,) a series 

 of thermometrical tables of observations, extending from 1853 to 

 1859, which will enable them to estimate the temperature of the 

 climate for each month of those years, and the mean annual temper- 

 ature. 



Professor Henry, of the Smithsonian Institution, made a 

 verbal communication relative to the application of the tele- 

 graph to the prediction of changes of the weather, particu- 

 larly in the city of Boston and its vicinity. 



It has been fully established by the observations which have been 

 made under the direction of the Smithsonian Institution, and from 

 other sources of information, that the principal disturbances of the 

 atmosphere are not of a local character, but commence in certain 

 regions, and are propagated in definite directions over the whole surface 

 of the United States east of the Eocky Mountains. 



From a careful study of all the phenomena of the winds of the tem- 

 perate zones, it is inferred that over the whole surface of the United 

 States and Canada there are two great currents of air continually 

 flowing eastward. These currents consist of an upper and a lower, 

 the former returning the air to the south which was carried by the 

 latter towards the north. The lower current, which is continually flow- 

 ing over the surface of the United States, is about two miles in depth, 

 and moves from the southwest to northeast. The upper or return 



