TORNADOES. 15^ 



at greater distances the noise is proportionally weaker. In any event, however, 

 the noise is sufficiently peculiar and distinct to create alarm and as a means of 

 warning should not be overlooked under any pretext. 



How TO Benefit by Signs. — In order to be prepared for the possible ap- 

 pearance of a tornado, so far at least as the above indications are concerned, let 

 every person situated in those regions of country where the tornado is of yearly 

 occurrence commence (to-day is none too soon) to carefully observe and record the 

 daily changes in the face of the sky, the variations of temperature, the direction 

 of the wind and the character and development of clouds. I do not mean that 

 any person should devote all or most of his time to this work of observation, 

 and possibly not even all of his spare time. For the sake of regularity and uni- 

 formity I will suggest certain hours for regular work of this nature, viz: 7 A. M. 

 2 and 9 P. M. These hours are not altogether arbitrary, for there is a reasonable 

 amount of prudence in their selection, looking to a proper and successful use of 

 the results of your labor. 



Should the violence of a storm be unusually marked during either the hours 

 of the forenoon or afternoon, or even in the night, it would be advisable to in- 

 crease the number of hours for observation and record, possibly making them 

 every hour or half hour, or even at shorter intervals, as the importance of the 

 case demands. By this means of frequent observation every feature of the storm 

 would become the subject of inquiry and quite probably the most important re- 

 sults attained. For purposes of investigation of this class of storms your observa- 

 tions need not continue throughout the entire year, at least in the Northern and 

 Western States, although such a length of record would by no means fall amiss of 

 much value. Yearly records will pay. However, observations without fail, 

 should commence by the ist of April and continue unremittingly until at least 

 the ist of September. Observations through the autumn can be maintained with 

 profit. It will be a valuable adjunct to this work of regular hour records if a 

 summary of miscellaneous phenomena is kept. Enter the dates of occurrence 

 and important particulars of such phenomena as auroras, mirage, meteors, lunar 

 and solar halos, prairie and forest fires, the migration of birds and insects, the 

 leafing and blossoming of trees, flowers and shrubs, droughts, excessive rainfalls, 

 earthquakes, zodiacal light, frosts and the formation of ice. Blank record sheets, 

 upon which such observations can be entered to advantage may be obtained free 

 of cost on application to the Chief Signal Officer U. S. Army, Washington, D. 

 C, provided, however, that a duplicate of each month's work, for which suffi- 

 cient blanks and stamped envelopes will be forwarded, shall be mailed on or near 

 the first day of each succeeding month, to the office of the Chief Signal Officer, 

 U. S. Army. All such observers under the title of Voluntary Observers, Signal 

 Service, U. S. A., in view of their labors in the interests of the Signal Service, 

 will be entitled to and receive a copy of the Annual Report of the Chief Signal 

 Officer, for that year within which they make the observations, and also a copy, 

 (monthly) of another publication of the Signal Service called the " Monthly 

 Weather Review," a most valuable journal of between twenty and thirty pages. 



