ASTRONOMY AND METEOROLOGY. 389 



sive ;" " rain," c. ; on the seventh day he remarks, " Assuming the 

 settled weather of the ' trades,' only requiring a rise of barometer to 

 assure nie of that fact." The day after, I find in his column of re- 

 marks, " Fine weather, every appearance of trades barometer up." 

 This remark is made the 5th of March, 1850, in 6 south lat. Had he 

 passed this cloud ring in August, he would probably have made the 

 same observations in 6 north lat., indicating that he had passed from 

 under the influence of this equatorial 'cloud belt. 



It is thus we arrive at a new application of the barometer, which 

 thus informs the navigator, when other means fail, when he leaves 

 and when he enters the trade winds. 



ON THE EQUIXOCTIAL STORM. 



THE following views respecting the occurrence of a periodic storm, 

 known as the Equinoctial, were communicated, by Prof. Loom is, to the 

 American Association, Albany : 



" About twelve years ago I made a somewhat extensive comparison 

 of meteorological observations, for the purpose of testing various popu- 

 lar notions wkh regard to the weather. My object particularly was 

 to determine whether any connection could be traced between the fall 

 of rain and the phases of the moon, or the seasons of the year. The 

 result of this investigation was, that many popular proverbs, with 

 regard to the fall of rain, have little foundation in truth. One of the 

 popular beliefs is worthy of note here, for many of the most scientific 

 men have faith in the fall of heavy rains at or about the period of the 

 equinoxes. 



" I propose to inquire whether rain is unusually prevalent about the 

 time of the autumnal equinox ] The register to which I first refer, 

 for an answer to this question, is that of the Royal Society of London, 

 which has been accurately kept for a period of (34 years. Comparing 

 the observations for the month of September, including 1920 days, 

 shows that there is annually in London a fall of rain greater by one 

 fifth for the last half of the month than the first half. This may be 

 adopted, therefore, as the law for London. But there is no indication 

 that there is a greater fall of rain than might be occasioned by the 

 change of season, and that no particular day can be pointed out in the 

 month of September where there ever was, or ever will be, a so called 

 equinoctial rain. If the number of rainy days, instead of the quantity 

 of rain, is taken into consideration, we arrive at the same result. I 

 will not attempt to conceal that the amount of rain for the five days 

 embracing the equinox is greater than for any other period of five days 

 throughout the month ; but if any one should be disposed to attach 

 any special importance to this circumstance, I would remark that the 

 amount of rain for the last five days of the month falls short of the 

 preceding five days by less than three per cent., and that this quantity 

 is too small to afford any satisfactory basis for a conclusion in a re- 

 search of this kind. Certain it is, that the difference is too small to be 

 detected, without a, most careful observation of the rain-gauge, and 

 inasmuch as the popular belief on this subject was certainly never 



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