808 



SIGNAL SERVICE. 



play that storm-winds exceeding twenty-five 

 miles an hour in velocity have occurred at the 

 display-station or within a radius of one hun- 

 dred miles. 



The total number of seaports and points on 

 the lakes and seacoasts where the storm-signals 

 are hoisted now is one hundred and eleven. 

 The points whence storm-signals are displayed, 

 however, are only those of the maritime mar- 

 gins of the field of research. The network of 

 the Signal Service stations now extends over 

 the continent from the Atlantic to the Pacific 

 coasts, and the intervening territory from the 

 Gulf to the Canadian frontier, and is in receipt 

 of daily telegraphic intelligence of the weather 

 from the Canadian Dominion and its outlying 

 posts. The office work is still hampered for 

 want of more stations in the interior and North- 

 west ; but it is thought provision will ere long 

 be made for supplying them, as a new trans- 

 continental telegraph-line is carried from Min- 

 nesota to the shores of the Northern Pacific. 



Sunset Stations. In this connection it may 

 be as well to add that, besides the regular 

 stations reporting by wire thrice daily to the 

 office of the Chief Signal Officer, " sunset sta- 

 tions," as they have been called, have also been 

 established. By careful study of the condi- 

 tion of the sky at sunset, especially on the 

 interior plateau, it was believed an advance 

 could be made toward a simple method of pre- 

 dicting the next day's weather, within the grasp 

 of any unscientific but intelligent observer. The 

 observers at the sunset stations note whether 

 the western sky at the precise time of sunset is 

 u fair," "foul," or "doubtful," and from these 

 observations with others (instrumental) they 

 make predictions for the ensuing day. Somo 

 of these observations are roughly spectroscopic, 

 the sunset report being based in part on such 

 different appearances of the sun and the effects 

 produced by his rays as are caused by their 

 passage through differently conditioned atmos- 

 pheric media. The sergeants of the Signal 

 Corps practiced in this kind of forecasting have 

 acquired considerable skill and accuracy in pre- 

 determining the local weather-changes; their 

 forecasts, as computed in the Chief Signal Of- 

 fice, having reached a percentage of 82 '6 of cor 

 rectness for trans-Mississippi districts, where 

 the meteorological conditions are most con- 

 stant, and 81-6 for the region east of the Mis- 

 sissippi Valley. " There can be no reason," 

 says the Chief Signal Officer, " why any intel- 

 ligent farmer, supplied with the necessary sim- 

 ple instruments, habituated to similar observa- 

 tions, and furnished with data, should fail to 

 attain an equal accuracy." 



Private Forecasts. To facilitate such private 

 forecasting, especially by the agriculturists of 

 the great West and the interior plateau, the 

 Chief Signal Officer has caused to be pre- 

 pared the " Weather - Case," or " Farmer's 

 Weather-Indicator," before mentioned. This 

 instrument is very simple, and when thorough- 

 ly tested, and by aid of the accompanying rules 



for using it, it is hoped agriculturists and per- 

 sons of ordinary education will find it possible 

 to determine for themselves in advance the 

 character of the weather from local indica- 

 tions. At isolated places, where the official 

 reports can not be had, the diligent practice 

 of such forecasting would probably in a short 

 time afford good results. It is to call into play 

 the intelligence of the popular mind and train 

 it in the highly utilitarian work of private 

 prognostications, as well as to explain its own 

 forecasts, that the Signal Office issues a " Sy- 

 nopsis " of the weather-data with every bulle- 

 tin of " Indications." That the farmer and sea- 

 man may know the changes going on each 

 day, and acquire the habit of tracing the se- 

 quences of meteorological phenomena, the 

 " Synopsis " is invaluable. Most of the news- 

 papers print only the "Indications," and omit 

 the "Synopsis" a practice to be greatly re- 

 gretted. The late Professor Smee, F. K. S., 

 one of the most gifted and practical of modern 

 scientists, was much interested in the storm- 

 signals hoisted on the English coast by Admi- 

 ral Fitzroy. After much personal intercourse 

 with the English fishermen, and close inquiry 

 into the use made of Fitzroy's "warnings" 

 among the humble coasters, he recommended 

 that " the reasons for hoisting the signal " 

 should be communicated to the public, that 

 those interested might study the official warn- 

 ing in its local applications. The Signal Ser- 

 vice has always encouraged the private study 

 and intelligent local application of its press re- 

 ports, and expects those who use them to con- 

 sult their own barometers and other instru- 

 ments, and to examine the local ^igns of the 

 weather, as clouds, etc., with the view of giv- 

 ing greater efficacy to its necessarily brief tele- 

 grams. Its plan is, not to deliver oracular and 

 dogmatic statements to the people, but to 

 guide them rather to meteorological knowledge 

 as it is daily needed. 



In the execution of the last-named plan, the 

 " Daily Graphic " of New York publishes every 

 twenty-four hours a reproduction of the Sig- 

 nal Service weather-map, showing the cyclonic, 

 anti-cyclonic, thermometric, wind, rainfall, and 

 other conditions prevailing over the country at 

 the time of going to press. These charts, ac- 

 cording to a plan devised by Lieutenant H. H. 

 C. Dunwoody, Acting Signal Othcer and Assis- 

 tant, are transmitted from the Washington of- 

 fice by telegraph. By this ingenious device, 

 it is found not difficult to transmit to any city 

 reached by telegraph and by the common tele- 

 graphic instrument such data prepared in the 

 Chief Signal Office as will enable any newspa- 

 per to reproduce on its pages the official weath- 

 er-map for the current period. Thus, the Sig- 

 nal Service weather-map for 1 A. M. of any 

 day, precisely as charted then in the Washing- 

 ton office, can be telegraphed to Boston, Chi- 

 cago, St. Louis, Indianapolis, or any other city, 

 and published, in any size the editors may 

 prefer, in the papers printed that morning ! 



