OF ARTS AND SCIENCES. 289 



are known upon the earth's surface, and have thus a character as gen- 

 eral as most subjects of geology or physical geography. The exami- 

 nation of these hydraulic forces, constantly at work in all tidal harbors, 

 has led the author of the memoir to a general specification of the 

 principles which ought always to govern constructions for the improve- 

 ment of such harbors ; and many rules are laid down, the understand- 

 ing of which must be useful to the hydraulic engineer. 



" The committee trust that this short summary of the contents of the 

 memoir will enable the Academy to make a proper disposition of it. 

 They abstain from expressing any opinion upon the accuracy or com- 

 pleteness of the memoir, as they hold to the wisdom of the rule, that 

 the Academy will not, by itself or its committee, become responsible 

 for the accuracy of any facts or opinions expressed by the authors of 

 any memoirs. 



" The committee recommend that the memoir of Lieutenant Davis 

 be referred to the Committee on Publications. All of which is respect- 

 fully submitted. 



" Daniel Treadwell, 

 Benjamin Peirce, 

 Joseph Lovering, 

 Henry L. Eustis, 

 Morrill Wyman. 

 " Boston, January 6th, 1852." 



Voted, to refer the paper to the Committee on Publications. 



The discussion of the subject of Mr. Guyot's communica- 

 tion at the last monthly meeting was continued by Professor 

 Peirce, Dr. W. F. Channing, Mr. J. H. Abbot, Professor Lover- 

 ing, Professor Eustis, Dr. B. A. Gould, Jr., Professor Horsford, 

 and Dr. Jacob Bigelow. 



Professor Peirce expressed his dissent from the opinion 

 advanced by Professor Guyot, in respect to the amount of 

 elevating force possessed by any whirlwind, which could be 

 generated by the conflict of opposite winds. He computed 

 the amount of this force in the case of a rotating body of air, 

 extending the full height of the atmosphere, and demonstrated 

 that it was insufficient to account for the phenomena to be 

 explained. He also computed the elevating force possessed 



VOL. II. 37 



