ADVERTISEMENT. Vll 



this translation prior to the meeting of the 

 British Association ; when an Abstract of the 

 original, was read by Dr. Lyon Playfair.* 



Great care has been bestowed upon the cal- 

 culations and estimates, which form so impor- 

 tant a feature in the body of the work, and in 

 the analytical results, which constitute the Ap- 

 pendix, upon the vast accumulation of which 

 the whole force of the reasoning depends. 

 Without presuming that the present edition is 

 perfect, or that some errors will not be found 

 in it, it is believed, that it contains fewer than 

 any other, and the editor has the satisfaction of 

 feeling that no pains have been spared to effectu- 

 ate this object. Those only, who may have lei- 

 sure and patience to go through all the calcula- 

 tions can estimate the time and labor they have 

 required. For the ready and able cooperation 

 of Professor Peirce, Dr. Samuel L. Dana, and 

 especially, Mr. Thomas Hill of this University, 

 in the laborious examination and revision of the 

 tables and analytical results, the editor is bound 

 to record his grateful acknowledgments. 



* The abstract occupies two pages of the Athenaeum of July 

 3d. 



