134 TEE POPULAR SCIENCE MONTHLY 



nervous temperament often affirm that they have forebodings of coming 

 thunderstorms or of rainy spells through a temporary disturbance of 

 their neural equilibrium. Physiologically considered, either from the 

 point of view of man or of the lower animals, these fore-warnings, often 

 verified, have some basis for their existence. The secret of the ex- 

 planation probably lies in the fact that all weather changes occur in 

 cycles — that is, a more or less constant order of events accompanying 

 every change. With the summer thunderstorm this cycle usually con- 

 sists of the following : rising temperature and humidity, pressure oscil- 

 lations, decreasing winds, increasing potential of atmospheric electricity, 

 thickening clouds and consequent growing darkness, distant lightning, 

 rumbling thunder, the lightning growing more vivid and the thunder 

 louder and louder as the storm approaches, a squall of wind coming 

 from the direction of the storm itself, accompanied by a marked fall in 

 temperature, inconstant humidity, large drops of rain, followed by a 

 downpour, often accompanied by hail. Another cycle, covering a con- 

 siderably longer period of time, is recognized as a precedent of the rains 

 of a barometric depression. Men differ greatly from the lower animals 

 in their sensitiveness to these various stages, and even different indi- 

 viduals, whether in the higher or in the lower orders of animal life, 

 show wide divergence in this respect. As a result, sensitive persons 

 and certain animals feel a coming change because for them the change 

 has already begun, they feel the rising humidity or the changing press- 

 ure before others, and they are, in fact, simply changes usually prece- 

 dent to the larger changes observed by all. However, one or more of 

 these changes may occur without reference to the various other changes, 

 thus explaining why the premonitions are sometimes amiss. But cycles 

 of this nature occur so frequently that traditions of a fair degree of 

 reliability have arisen. It might be added that most of the reliable 

 proverbs based upon the behavior of animals are ultimately concerned 

 with changes of humidity. To such changes certain animals appear to 

 be super-sensitive, while most men are phlegmatic in this respect. 



That rain has resulted from the concussions attending the old- 

 fashioned celebration of Independence Day (July 4) or during great 

 battles, particularly those of the Civil War, has long been a popular 

 belief. Even before gunpowder was used for military purposes it was 

 held that rain was produced by the clashing of swords and armor in 

 physical combat. The explanation offered was to the effect that wide- 

 spread concussions caused the small vapor particles floating in the air 

 to coalesce to form raindrops, the dust and smoke furnishing *:hc neces- 

 sary nuclei of condensation. Eecords obtained in all parts of the 

 United States and covering long periods of years fail to sh,)w that pre- 

 cipitation is heavier or more frequent upon July 4 or 5 than it is upon 

 July 2 or 3. Moreover, so far as the records are available, the rain 



