180 ANNUAX, REPORTS OF DEPARTMENT OF AGRICULTURE. 



to eni^inecrs and those dealiiif]; with the storage of water for power 

 purposes and its distribution for irrigation. 



The daily bulletins of weather conditions over the great corn, 

 w^heat, cotton, sugar, and rice growling States have been issued regu- 

 larly from about 40 selected ])oints in tliose districts, the total issue 

 amounting to more than 2,000 copies daily. The demands for 

 the extension of these services have ];een numerous and persistent, 

 especially for the establishment of additional telegraphic reporting 

 stations in the cotton-growing sections of 'J'exas and Oklahoma and 

 the wheat-growing districts of Montana and the Dakotas. These 

 demands have been partially met by the establishment of about 20 

 additional telegraphic reporting stations, mostly in the western 

 portion of Texas and in the Dakotas. The necessity of more stations 

 of this character is still being urged by the many beneficiaries of these 

 services. 



The published annual summaries of climatological data for 1910, 

 for the several States, have served as valuable additions to the series, 

 which has been continued since 1S9G. 



The preparation and printing of the 106 Summaries of Climato- 

 logical Data, covering the entire United States, have been completed. 

 These summaries have proved almost invaluable in answermg the 

 thousands of requests for information regarding the climatic features 

 of the diiTerent portions of the country, and the public demand has 

 been so great that reprints of several of the earlier issues have already 

 become necessary. 



During the 3^ear there was prepared and issued as "Bulletin V. Frost 

 Data of the United States," a set of charts showing the average dates 

 of first killing frost in autumn, average dates of last killing frost in 

 spring, earliest dates of killing frost in autumn, latest dates of 

 killing frost in spring, and the length, in days, of the crop-growing 

 season for all portions of the United States. These charts w^ere 

 prepared from the records of about 1,000 cooperative observing 

 stations having the greatest length of record. As the observations 

 selected were made largely in the open country and therefore removed 

 from the artificial conditions that prevail in the cities, where most of 

 our regular stations are locate<l, they show the conditions that are 

 liable to prevail in the fields, orchards, and gardens more accurately 

 than ever before attempted. 



The Weather Bureau derives much of its important climatological 

 data from the records of its cooperative observers, of whom there are 

 at present about 4,000, reporting from points well distributed through- 

 out the entire United States, including Alaska, Porto Rico, and the 

 Hawaiian Islands. Changes in this feature of the w^ork included the 

 opening of 258 new cooperative stations, and the discontinuance of 

 150 formerly in operation. 



The great extension of the agricultural interests, especially those of 

 trucking and fruit raising, necessitates more exact knowledge regard- 

 ing the details of the climate of the country as an aid in determining 

 the crops and fruits best suited to the various portions. At the 

 present time this need can only be met by the data furnished by the 

 cooperative observers of the bureau. 



The demands for the extension of these reporting stations have 

 been much greater than it was possible to meet. As a rule, new 

 stations have been established onlv in the more recently settled dis- 



