TORNADO STUDIES FOR 1882. 77 



more definite information concerning the conditions precedent and favorable to 

 the formation of tornadoes in general; the phenomena and laws of cloud develop- 

 ment; the velocity and power of centripetal currents within the cloud vortex; 

 additional statistics respecting the tornadoes of former years ; the arrangement 

 and perfection of an acceptable scheme whereby reliable warnings can be sent to 

 certain communities in advance of the tornado, announcing that conditions are 

 favorable to its formation ; and lastly, to prepare and disseminate such information 

 as will direct people how to act in defense of their lives, and to a certain extent 

 of their property, during the approach and passage of a tornado. In the accom- 

 plishment of these momentous results or in bringing to light new points of value, 

 I am desirous to enUst the active support of every intelligent person throughout 

 the Lower Missouri Valley or elsewhere. There are not a few ways in which even 

 the humblest can assist. If you cannot give any facts concerning a tornado of 

 recent date write me what you know about one or more whose dates of occurrence 

 number many years past. In every description of the tornado conform as nearly 

 as possible to the character of the questions propounded in the accompanying 

 circulars. Perhaps you can send me some article or publication bearing upon the 

 climatology or meteorology of your State, or some portion of it. Photographs, 

 sketches or printed cuts of the effects of the violence of any particular tornado, 

 no matter what date, would be very valuable and thankfully received. 



As it will probably be impossible (owing to press of other work) for me 

 to visit and conduct a personal examination in the case of every tornado that 

 may occur in the Lower Missouri Valley or in adjoining States during the year, 

 I will deem it a great favor, and it will certainly be a matter of most valuable ser- 

 vice, if some one in the vicinity of a tornado's path will kindly undertake to 

 furnish me (at his earhest convenience after the tornado's occurrence) with a 

 complete history of its entire track. In performing this task, be careful to state 

 as accurately as possible the place of beginning. This location is not necessarily 

 where the tornado cloud first descended to the earth, although it may be, but 

 more truly and hence more accurately, it is that particular spot or portion of coun- 

 try over which (perhaps at a great height above the earth) the funnel-shaped 

 cloud was first seen to form. 



Upon determining the place of commencement, carefully ascertain all the pre- 

 liminary conditions of atmospheric changes existing prior to the development of 

 the tornado cloud. In conducting the examination along the track and on both 

 sides of it, make use of the questions and remarks contained in the respective 

 circulars, according as one or the other is required. In determining the exact 

 locality of final disappearance, exercise no inconsiderable vigilance, for you may 

 most easily be deceived. It is a characteristic feature of the tornado cloud to 

 rise suddenly from the earth and, continuing its northeastward course in the lower 

 regions of the atmosphere, again reach terra firma after an interval of several 

 miles. You may find a number of these gaps along the tornado track you are ex- 

 amining, but do not mistake them for points of termination ; rather look upon their 

 existence as indubitable evidences of tornado (latent) activity, a sign of reappear- 



