104 Attempts to Foretell the Weather. 



partakes of tlie character of a mercantile letter of advice, but 

 instead of " shipped from so and so, so many chests of tea," it 

 tells that air currents, dry or moist, have passed over certain 

 places, and may be expected to visit other localities as soon as 

 time permits. Labours of this kind are not likely to lose 

 their value through the progress of science, because the dis- 

 covery of general laws regulating atmospheric changes would 

 not do away with the necessity for watching as accurately as 

 possible every indication of the modifications the effect would 

 experience at any particular place. If, for example, Mr. 

 Balfour Stewart's theory of the action of the planets on the 

 sun should be verified by observation and experience, we might 

 calculate in advance when there would be a strong outpouring 

 of heat ; but a great many circumstances, arising from a multi- 

 plicity of causes, might help to decide when and to what extent 

 any particular locality would be warmed. 



That weather changes occur without law, no one believes,, 

 and if by law, why should not the law be discovered ? The 

 doubt which many have felt has arisen from a belief that too 

 many forces co-operated, and too many incidents modified their 

 action, to admit of calculation with the precision that science 

 requires, or that utility needs. To this it might be replied 

 that there may be certain conditions sufficiently dominant to 

 ensure a general or average result of a particular kind when- 

 ever they prevail, and that although we may not be able to say 

 that London will be visited by a rain or thunder-storm on any 

 particular day next year or the year after, we may find reason 

 for predicting that on, or close to such a date, a rain fall or 

 electric disturbance will take place within the limits of a me- 

 teorological district of which the metropolis may form a part. 

 No one can deny the possibility, or even the probability, of 

 attaining to this class of information, and if it is reached at all, 

 it is very likely to be arrived at by the method of watching 

 coincidences, and thus ascertaining an empirical law. 



Captain Saxby is very confident that he has discovered a 

 great weather law, according to which " the moon never seems- 

 to cross the earth's equator without there occurring at the same 

 time a palpable and unmistakeable change in the weather. 

 Such changes most commonly are accompanied either by 

 strong winds, gales, sudden frost, sudden thaw, sudden calms- 

 or other certain interruptions of the weather according to the 

 season."* 



Mr. Pearce and the "Astro-meteorologists," as they call 



themselves, not only make very positive assertions that weather 



changes accompany or follow certain planetary configurations, 



but they plunge head over ears into theories by which they 



* Saxbg's Weather System, p. 7. Longmans. 



