XX EXPLANATION OF TABLE (AV 



in the column headed " Extent " do not always correspond with the time elapsed h'om 

 the date of commencement to that of the close of the series, as given in the column 

 following. The column headed " Extent" shows the number of years and months 

 of actual observation. The contents of the table are generally brought up to the 

 end of the year 1874. 



When more than one series for any limited locality was on record, either cover- 

 ing the same period or for different years, consolidated results are given, at least for 

 the most prominent localities. For these consolidated results, the several monthly 

 values observed for any one month and for any one year were first combined by 

 taking the mean, and these monthly means for the several years were afterwards 

 united. This mode of combination must necessarily be followed on account of the 

 annual inequality in the rain-fall. The observer's name is stated, except for the 

 series of observations taken by the United States Army, and for .those taken by . 

 the New York Academy system, and necessarily for a few other stations where the 

 observer's name was not given. The observations of the army were generally taken 

 by the assistant surgeon of the post, and those of the State of New Yoi'k by the 

 professors of the academies. The abbreviations used in the last column headed 

 " Refei'ences " are principally the following: — 



Ar. Met. Reg., 1855, denotes the U. S. Army Meteorological Register, Washington, 1855. 



At. Met. Reg., 1860, denotes the U. S. Medical Statistics forming the third collection of the 



Army Meteorological Publications, Washington, 1860. 



Met. Obs. Vol. 1* denotes the Results of the Meteorological Observatious made under the 



direction of the Patent Office and the Smithsonian Institution, 

 Washington, 1861. 



Surv. N. and N. W. Lakes denotes Manuscript and Annual Report of the Survey of the N. and 



N. W. Lakes under the direction of the U. S. Topographical Engi- 

 neers. 



S. O. denotes the Manuscripts by the observers operating in connection with 



the Smithsonian Institution. 



S. CoU. denotes Manuscripts collected at different times by the Institution. 



N. Y. Acad. Sys. denotes the Reports by the Regents of the Academies of New York. 



MS. from S. G. O. denotes the latest Observations at Military Stations west of the Missis- 



sippi River, obtained from the Surgeon General's Office, U. S. A., 

 1860-74. 



Am. Aim. denotes American Almanac, Boston. 



Sm.itll. Con. to Knowl. denotes Smithsonian Contributions to Knowledge, Washington. 



Sill. Jour. denotes American Journal of Science, New Haven. 



Mem. Am. Acad. denotes Memoirs of the American Academy of Science, Boston. 



Trans. Phil. SOC. denotes Transactions of the American Philosophical Society, Phila. 



London Gard. Ch. denotes London Gardener's Chronicle, London, England. 



And various others whose meanings are sufficiently apparent. 



* Designated " P. 0. and S. I., Vol. I," in the first edition of the Eain-fall Tables and in the Temperature Tables. 



