PEEFACE TO THE SECOND EDITION. IX 



ogists. A few tables have been added to Dove's collection, computed by 

 Glaisher, Captain Lefroy, and by myself. Most of the tables refer to tem- 

 perature, only two to moisture. Two tables of Barometrical Corrections 

 have been placed in the Hypsometrical series, where they were needed, 

 until they can be joined by others to make a set in this series, which still 

 awaits new contributions, especially for these last two departments. 



The Miscellaneous series is but begun. I have prepared a list of useful 

 tables, which would be no doubt welcome to the lovers of Terrestrial Physics, 

 and which may be published at some future occasion, if you should then 

 find it expedient. 



The present collection being designed, not for the scientific only, but for 

 the observers at large, the propriety of the explicit and popular form of 

 the explanations which accompany the tables, and of the directions for 

 using them, will readily be understood. 



I close by the remark, that, in every instance, the works from which the 

 tables were taken have been carefully noted, and due credit given to their 

 authors. For all the tables without author's names, I am myself respon- 

 sible. 



I remain. Sir, 



Very respectfully, yours, 



A. GUYOT. 



Peinceton, N. J., December, 185T. 



