SIGNAL SERVICE. 



801 



From tho telegraphic data, of course, th 



daily Indications '' aro prepared. The 



enil 



the tri- 

 gen- 



i-, tliis: Having takenthoirinst.ru- 

 .nnl other observations at either of the 

 tho observers prepare their 

 reports in richer, by which expense for the 

 uK'irrttms and time in their transmission are 

 saved, as well as greater accuracy secured. 

 The observations include the actual and the 

 corrected Tradings of tho barometer and ther- 

 mometer, and their changes since previous re- 

 port; the direction and velocity of the wind, as 

 well as its pressure ; the relative humidity of 

 the air; the amount of rain or snow fallen 

 since last report ; the amount and form of 

 clouds, auroras, haze, fog, smokiness, frost, 

 etc. ; and to these data the river stations add 

 the changes or oscillations in the rivers, and 

 the seacoast stations the direction and degree 

 of the ocean-swell. The maximum and mini- 

 mum range of the temperature in the past 

 twenty -four hours are also given. Those datn, 

 condensed by means of the cipher-code into 

 ten or twelve words for each report, as soon as 

 received in the telegraph -room of the Wash- 

 ington office, are translated from cipher and 

 entered on the bulletin blanks, and also entered 

 in their proper places on the weather-maps. 

 This is done in the room where the predictions 

 and storm-warnings are prepared after all the 

 dispatches are in, and under the eye of the as- 

 sistant engaged in shaping the weather-predic- 

 tions for the public press. This was, for some 

 years after the Signal Service was organized, 

 pioneer work the first attempt at weather 

 forecasts based on simultaneous telegraphic 

 reports ever set on foot. 



Synoptic Weather-Map. As a concomitant 

 and indispensable aid in the analysis of the re- 

 ports and in utilizing them for purposes of pre- 

 diction, synoptic weather-maps, which would 

 show the concurrent conditions of the weath- 

 er as they simultaneously and actually exist 

 over the country, for tho first time became 

 possible in 1870. The aim kept in view bad 

 been to secure a bird's-eye view of the at- 

 mosphere, and the data thrice daily supplied 

 by the Signal Service reports sufficed for the 

 construction daily of three maps, showing tho 

 weather - status and all the wind and storm 

 movements in their connection and interde- 

 pendence. By preparing a graphic weather- 

 map embodying the telegraphic data furnished 

 to the Chief Signal Officer every eight hours 

 in the day, the officer charged with formu- 

 lating the storm-predictions could gain and 

 retain a clear idea and mental image of the 

 aerial ocean. A great soldier has said, " There 

 is nothing ideal in war " ; and it may be said 

 with equal force, there is no work which for 

 its intelligent execution demands greater pre- 

 cision of method, more copious and circum- 

 stantial details, and closer attention to the de- 

 velopments of the hour, than weather-forecast- 

 ing over a continent. The weather-map brings 

 all these minutiae within view, and makes the 

 VOL. six. 51 A 



meteorologist master of the whole mass of ob- 

 M-rvations, as hours consumed in the study of 

 the numerical data could not do. Every we;ith- 

 er-map is, therefore, a generalization in itself, 

 as well as a record of the data. A series of 

 weather-maps is a history of the ebb and flow, 

 the fluctuations arid tossings of the aerial ocean, 

 and of the more subtile yet influential pro< 

 concerned in producing the weather and deter- 

 mining the climate of the country. 



These maps, offering in a synoptic view the 

 results deduced or deducible from thousands 

 of observations, enable the Chief Signal Officer 

 to prepare statistics nnd reports for the use of 

 individuals, institutions, and the public jour- 

 nals, upon special requests for such meteoro- 

 logical information as their business or publi- 

 cations demand. The calls for such consoli- 

 dated data, and the elucidation of obscure 

 climatic conditions, which these reports and 

 maps alone can supply, have increased until 

 compliance with them has become a work of 

 magnitude, requiring a greater force than the 

 office now has at command. 



Military Organization. An economic fea- 

 ture of the Weather Bureau is that it is a mili- 

 tary service. All its observational work is 

 done by enlisted men and officers of the anny^ 

 and all its official publications are prepared 

 under authority, and with the regularity and 

 dispatch to be had only under military disci- 

 pline. The military relations of the Signal 

 Service have been found by experience to give 

 it great advantages in extending its network 

 of stations in the sparsely populated territo- 

 ries of the country, whence, for the develop- 

 ment of its scientific research, it must draw 

 many of the most indispensable meteorological 

 reports. The observers of the Signal Corps 

 are trained not only in the art and practice of 

 miltary field-signaling, but in the ordinary ar- 

 my drill nnd rules and habits of discipline ; so 

 that in time of war they constitute a part of 

 the regular fighting force of the nation, ready 

 for active service in repressing internal disor- 

 der and repelling foreign invasion. Consti- 

 tuting, in fact, only a portion of the regular 

 army, occupied in time of peace with scientific 

 work, but available for duty in the ranks in 

 the emergency of war, the cost of their main- 

 tenance is but a small additional burden upon 

 the country, far more than requited by their 

 meteorological services to it. Experience has 

 fully shown in other countries that arduous 

 meteorological labors such as they perform can 

 not be secured from any civil corps. As the 

 Signal Service observers must report several 

 times a day to the Washington office, each reg- 

 ular general report serves in effect as a tele- 

 graphic roll-call of all the stations spread over 

 the country from the Atlantic to the Pacific, 

 and from the lakes to the Gulf of Mexico, in- 

 suring promptitude, vigilance, and steadiness 

 in the entire Signal Corps. 



In addition to this regular force of military 

 observers, there was transferred to the Signal 



