180 ANNUAL REPORTS OF DEPARTMENT OF AGRICULTURE. 



be placed immediately at the evaporating pan, and the coefficient of 

 evaporation is such that oreat caution must be used in making the 

 transition from the evaporation on tlie shore to the corresponding 

 evaporation over a large water surface. It seems probable that the 

 same coefficient of evaporation exists over the entire lake, except 

 within a comparatively few feet of the shore, where land effect merges 

 with the water ett'ect. 



It has been found by special experiments that the " Salton Sea " 

 ceases to exercise any influence upon evaporation during the summer 

 at a distance of about 1,000 feet from the shore. This would indi- 

 cate that there is no effect of the sea by way of changing the climate 

 of the country about its neighborhood. 



The phenomena of evaporation should be developed fully in con- 

 nection with forest and plant growth, and for this purpose the 

 "Weather Bureau is cooperating with the Forest Service at the 

 Coconino Forest Experiment Station near Flagstaff, Ariz., and at 

 Fremont, near Manitou, in Colorado. 



NEW TEMPERATURE NORMALS. 



In Weather Bureau Bulletin S, "Beport on the Temperatures and 

 Vapor Tensions of the United States," the monthly mean tempera- 

 tures reduced to a homogeneous system for about thirty-three years' 

 record have been collected for stations having a long record, about 

 100 in all. 



A series of 481 charts, covering the interval from January, 1873, 

 to December, 1909, inclusive, with corresponding annual charts, has 

 been prepared showing the monthly and annual temperature de- 

 partures from these long-record normals for the United States. 

 Copies of these charts are being printed, and when assembled will 

 give a complete history of this important phenomenon for more than 

 a third of a century. By using these charts the current short-record 

 normals of any station may be corrected to the corresponding thirty- 

 three-year normal, and this will be undertaken later. 



MARINE DIVISION. 



This division is charged with the ocean and lake meteorological 

 work, the supervision of the wireless-telegraph weather service, and 

 the work of the vessel-reporting service. 



While the collection, compilation, computation, and publication of 

 all ocean meteorological data from vessels traversing the oceans and 

 lakes are by law under the Weather Bureau, a duplicate of the infor- 

 mation published by the Weather Bureau has to be furnished to the 

 Hydrographic Office of the Navy Department. The act making ap- 

 propriations for the legislative, executive, and judicial expenses of 

 the Government for the fiscal year ending June 30, 1911, provides 

 that— 



Hereafter the pilot charts i)rei)ared in the Hydrographic Office shall have 

 conspicuously printed thereon the following: " Prepared from data furnished by 

 the Hydrographic Office of the Navy Department and by the V^'eather Bureau 

 of the Department of Agriculture, and published at the Hydrographic Office 

 under the authority of the Secretary of the Navy ; " and all meteorological in- 

 formation received by the Weather P.ureau of the Department of Agriculture 

 necessary for and of the character of such information heretofore used in the 

 preparation of the pilot charts shall continue to be furnished with all possible 

 expedition to the Hydrographic Office for use in the preparation of said charts. 



