PREFACE 



TO THE SECOND EDITION. 



To PROF. JOSEPH HENRY, 



Secretary of the Smithsonian Institution. 

 SIR, 



IN sending to you the Meteorological Tables composing the first edition of 

 this Tolume, published in 1852, I expressed the desire that they be consid- 

 ered as a first collection, containing the tables most needed at the time by 

 the meteorological observers engaged in the system carried on under the 

 supervision of the Smithsonian Institution, but destined to be increased. 

 It was in that expectation, I remarked, that the tables had been arranged in 

 independent series, as a kind of framework, into which a larger number 

 could readily be inserted. It seemed, indeed, highly desirable to offer to 

 the Meteorologist and Physical Geographer, not only the tables they daily 

 need for working out the results of their observations, but also such a vari- 

 ety of tables, computed from different elements, or by different methods, or 

 adapted to different measures, as to enable every one to choose among them 

 those that he most approves, and at the same time properly to compare and 

 to appreciate the results obtained by others. 



Thanks to the congenial spirit with which the elevated views of the foun- 

 der of the Smithsonian Institution are carried out, that character of general 

 usefulness is not wanting in the present volume. With your agreement, the 

 present edition contains more than three times as much matter as the first ; 

 and a rapid 'indication of the additions will suffice to justify them, and to 

 show that, in selecting or calculating the new tables, the object just men- 

 tioned was constantly kept in view 



As to the tables in the first edition, I must remark that, several of them 

 having been printed in my absence, the copy prepared for the printer, in 

 which decimals had to be left out, failed to give always the nearest value. 

 Though these errors are too small to have any importance whatsoever in 

 Meteorology, a careful revision of all the tables on the original computations 

 was made, and they were corrected in the present edition The few actual 

 misprints which were discovered are indicated in a table of errata to the 

 first edition. 



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