178 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



lished in the monthly section summaries are now arranged with 

 reference to 12 climatological districts, conforming to the natural 

 watersheds of the United States, and a district editor appointed to 

 each district supervises the preparation of the material, which is 

 finally assembled and printed in the Monthly Weather Review. 



The Review in its present form is a strictly climatological journal. 

 It contains, in addition to the current climatological history, occa- 

 sional important papers on the relation of climate to agriculture, 

 irrigation, transportation, and evaporation, the effects of forests on 

 climate, and other similar contributions, but they are presented in a 

 nontechnical manner as far as possible. 



The plan of preparing and publishing climatological summaries, 

 giving in some detail the vast amount of material that the Weather 

 Bureau has been for many years collecting, has continued during the 

 year. The entire United States will eventually be covered in these 

 reports, which will be made up for 106 districts in all. Their pub- 

 lication is advancing rapidly and with the completion of the series, 

 which will soon be accomplished, the public will have in form for 

 ready reference the longer records of climatological data for all parts 

 of the country. 



MEASUREMENTS OF SNOWFALL. 



Since the water used during the summer for irrigation in those 

 western districts where irrigation is practiced depends largely upon 

 the snowfall on the mountains of that region, the importance of meas- 

 uring the snowfall in remote places which are inaccessible during 

 the winter has made it necessary to discover some means of auto- 

 matically measuring the seasonal snowfall at places where no per- 

 manent observers can be obtained. Experiments have been carried 

 out under the direction of Prof. F. H. Bigelow for this purpose. 

 A large number of stations have been equipped with comparative 

 apparatus, as follows: (1) Snow bins, or cubical boxes, 5 feet on a 

 side, standing on a frame so that the top is 10 feet above the ground; 

 (2) standpipes, 10 inches in diameter and 10 feet high; (3) plat- 

 forms, 10 feet square on the ground; (4) vertical scales, graduated 

 in feet and tenths; and (5) the ordinary small snow gauge used by 

 the Weather Bureau for many .years. 



Observations made during the winter of 1909-10 indicate that the 

 snow bins, fitted with a system of louvers on the inside to prevent the 

 wind from blowing out the snow and to insure a level deposit within, 

 catch very nearly the actual amount of fall. The stand pipe fails 

 to catch the right amount of snow by 20 per cent to 50 per cent. The 

 wind drifts the snow on or off the platforms, making the measure- 

 ments wholly unreliable. The catch of the small snow gauges is also 

 rendered imperfect by wind eddies, which blow around the opening 

 of the cylinder and carry a portion of the snow past the mouth with- 

 out depositing it. The vertical snow scales are placed against trees 

 or posts to show the depth of the snow lying on the ground at a given 

 time. Further experiments will doubtless soon develop the best 

 practical form of apparatus. 



EVAPORATION STUDIES. 



The evaporation observations and studies, which were begun in 

 1907, have been continued during the year under the direction of 

 Professor Bigelow, who is now preparing a report summarizing these 



