42 ANNUAX, REPORTS OF DEPARTMENT OF AGRICULTURE. 



SOLAK RADIATION. 



Studies in solar radiation have been continued at Washington and 

 at INIount Weather, and were begun at Madison, Wis., during the 

 year. Arrangements are now being made for additional pyrhelio- 

 metric observations at various points in the region west of the Great 

 Lakes and the Mississippi River. The most striking features of the 

 record for the year were the high value of the radiation in February 

 nnd March on the front of marked high barometric areas and the low 

 value during the protracted hot wave in May. 



It is believed that the determination of the intensity of direct solar 

 radiation, of the quantity of heat received diffusely from the whole 

 sky, and of the rate at which heat is lost at night, will not only be 

 of value to climatologists generally, but will also be utilized by the 

 weather forecaster. A demand has already been made by biologists 

 for accurate data of this nature. 



FORECASTS AND WARNINGS. 



During the hurricane season of 1910, only two tropical storms of 

 note visited the United States. That of September, 1910, moved from 

 near San Juan, P. R., on the 6th to the Texas coast near the mouth 

 of the Eio Grande on the 14th. Warnings were issued regularly 

 until the storm disappeared. There was no loss of life nor was much 

 damage done, except on the north coast east of San Juan. The hurri- 

 cane of October was more severe, yet the damage was reduced to the 

 minimum by timely warnings. 



Plans are now under consideration for the systematic extension of 

 the field of meteorological observation by means of cooperation 

 between the Weather Bureau and the steamship lines equipped with 

 wireless plying in Atlantic and southern waters, through which it is 

 hoped to be able to locate hurricanes and other severe storms imme- 

 diately following their inception. 



Forecasts of the general character of the weather for a week in 

 advance were issued weekly during the year. These, in the main, 

 have proved reasonably accurate. The weekly forecast issued on 

 August 21, 1910, announcing that a cool wave would pass over the 

 country the latter part of the ensuing week, attracted special atten- 

 tion, and its complete verification called forth widespread and favor- 

 able comment. 



These comparatively long-range forecasts are based on a study of 

 the atmospheric conditions exhibited on the daily chart of weather 

 observations for the Northern Hemisphere. 



Special attention has been given to frost warnings in the spring, 

 principally in the cranberry marshes of Massachusetts, in the citrus- 

 fruit districts of Florida, and in a number of the orchard sections 



