Rules for WeatJier Prediction. 87 



The scientific investigator or student who longest apphecl liim- 

 self to the study of American weather endeavored a few years 

 since to deduce a practical rule for weather forecasts which might 

 he a]3plied to current and daily work. It is significant that no ■ 

 single application of this rule or theory has ever been made. If 

 the test had been made it is to be feared that the criticism of 

 Strachey would recur, viz, that theory finds not its counterpart 

 in actuah values. 



It may or may not be indicative of the state of meteorology 

 that the eleven rules for practical predictions laid down by me 

 in "'American Weather " in 1888 have received no accretions. 

 Many are willing to indulge in criticism and glittering gener- 

 alities, but in any scientific work practical and jjarticular appli- 

 cations are demanded. Careful and continued observations have 

 indeed determined the usual paths of storms, but most uncertain 

 and so far indeterminate have been all researches to so determine 

 the cause of storm development and movement that from ob- 

 served meteorological phenomena can be seen not onl}'' the cer- 

 tainty of the storm's approach l)ut also its particular course. 



What do experts abroad think? Abercrombie says: "The 

 service of weather forecasting can ne^'er be treated mathemat- 

 ically. * ^" * Many isolated principles have been discovered, 

 but no attempt has l)een made to lay down the broad principles 

 of the science of the weather as a whole." The terse dictum that 

 " The successive ' changes in the ^hcqie of isoliars * '•' * in- 

 dicate the sequence of weather ' in any place " is declared to be 

 the fundamental principle of all synoptic meteorology, and we 

 have only to work out the local details connected with the 

 changes of isobars to formulate and connect therewith sequent 

 and api^ertaining weather changes. 



It may well be questioned if any meteorological expert out- 

 side of the British office accepts this principle or limitation of 

 Abercrombie's. Statistical methods, he goes on to remark, are 

 practically devoid of physical significance, and through misuse 

 have tended to bring modern meteorology into disrepute. While 

 most meteorologist^ agree with him in their disapproval of 

 certain statistical methods as applicable to meteorology, yet 

 they endorse others, these or those according to circumstances, 

 as valuable or invaluable aids to successful work in weather 

 forecasting. 



Among investigators followino- statistical methods is M Teis- 



