INTKODUCTION. 



The following memoir contains in tabulated form the abstracts of all the records 

 of observations of the rain-fall which have been made from the early settlement of 

 this country down to the close of the year 1866, so far as they could be obtained. 

 These records are from about one thousand two hundred stations, and consist of 

 the observations made under the direction of the Smithsonian Institution, assisted 

 since 185-4 by the Patent Office and Department of Agriculture; of those by the 

 Medical Department of the United States Army, of those by the United States 

 Survey of the North and Northwest Lakes, of those made by the New York 

 University System, by the Franklin Institute in Philadelphia, and also of those 

 by other scientific institutions and individuals. For a more definite account of the 

 various sources of information we would refer to subsequent pages. It is proper, 

 however, that we should here express our obligations for the valuable co-operation 

 of the Medical Department of the Army under Surgeon-General Barnes, who has 

 given us free access to all the unpublished records, and also for that of the De- 

 partment of Agriculture under the Commissioner, General Capron. 



These materials were placed in the hands of Mr. Charles A. Schott, of the United 

 States Coast Survey, whom we had previously employed in the reduction and dis- 

 cussion of the observations of Kane, Hayes, McClintock, and others, which have 

 been published from time to time in the Smithsonian Contributions to Knowledge. 

 The tables which were prepared as the basis for future study are in themselves of 

 much utility in regard to the practical knowledge which they afford of the special 

 climatology of the United States, while the deductions which have been drawn from 

 the discussion of the facts presented in these tables, and which are principally 

 expressed in the maps of the distribution of the rain-fall, are intimately connected 

 with the agriculture, commerce, and mechanical industry of the country, while they 

 constitute a valuable contribution to the physical geography of the globe. 



The aim was to collect information on the rain-fall from all sources of observa- 

 tion, whether published or in manuscript, but the <jifort could only be approxi- 

 mately successful, since, however diligent may have been the search, much must 

 remain undiscovered. On this account the tables have been so constructed as to 

 admit of continued additions and corrections. 



The degree of precision of such observations, made, as they have been, by so 

 many persons of different knowledge and experience, must, of course, vary within 

 a considerably Avide range ; still it would appear from the results of the discussions 

 of Mr. Schott that they are sufficiently exact to afford satisfactory evidence of 



1 December. 1871. ( 1 ) 



