INTEODUCTION TO RAIN-FALL TABLES. 



COLLECTION AND TABULATION OF RECORDS AND RESULTS. 



It is intended in the following pages to present, as a contribution towards the 

 advancement of American climatology, the leading facts connected with the aqueous 

 precipitation over the area of the United States ; also to include such scanty records 

 from other jiarts of North America and from Central and South America as could be 

 collected. It has been the aim to bring together from all sources, records of observa- 

 tions of the fall of water, in rain or snow, from the earliest observers to those of the 

 present time. 



The first work, after collecting the material, was to form tables giving a summary 

 of monthly amounts of rain-fall, arranged for each State and Territory separately, 

 for each year. These tables served as the basis from which most of the deductions 

 given in this memoir are derived ; but, on account of their voluminous character and 

 consequent great expense of printing, they are not published at present. They can 

 be referred to, however, at the Institution, for more minute information* respecting 

 the nature of the record than could conveniently be given in the printed tables, which 

 contain all that is known or essential to the true valuation of each series. Tables A 

 and B of this memoir are directly derived from these manuscript tables, and present 

 their general contents in a more condensed form. 



As early as 1853 and 1854 the Smithsonian Institution had collected a large 

 number of rain records, and tabulated the monthly and annual amounts, and given 

 other information respecting the rain -fall for stations occupied up to that period. 

 This collection was placed in my hands in August, 1867, was revised and enlarged, 

 and the records and results, generally, were brought up to the close of the year 1866. 

 As no definite limit for closing the records was assigned, the tables at many stations 

 include those for the year 1867, and, for some few localities, those for a part of 1868 

 also. Additions to any table can readily be made hereafter, as date and reference are 

 given for each series. 



* In these manuscript tables any break in the regularly noted series for any month is indicated by dashes, and when 

 there was no precipitation during the interval a zero (o) is inserted. In the monthly summaries the insertion of a 

 star (*) indicates incomplete record, the sign (f) indicates a doubtful result, and the sign ( J ) an approximate result. 

 The series of Smithsonian records of 1860 were in part lost or damaged by fire, in January, 1865 ; many of these, how- 

 ever, have since been replaced by the observers when called upon for duplicates. 



(IX) 



