1874.] 1J5 [Chase. 



so great and so frequent, that my convictions of causal nexus are often 

 wavering. I cannot expect that others, who have been less interested in 

 the study of cyclical meteoi'ology, will accept my qualified belief in 

 systematic distui-bances by Jupiter or other planets, until a sufficient 

 number of observations have been compared at a sufficient number of 

 stitions, to furnish data for successful prediction. 



Notwithstanding my persuasion that such data will be at some time 

 attainable, I see, as yet, few encouraging indications of any conclusive 

 and satisfactory termination for my researches in this particular direction. 

 This very vagueness and lack of certainty furnishes a new and somewhat 

 unexpected argument in favor of appreciable lunar weather-action ; for, 

 if the tabulation of rainfall in planetary cycles had not shown so great 

 deviations from uniformity, the regularity might, perhaps, have been 

 regarded as an accidental resultant from some unknown law of harmonic 

 functions, entirely independent of the influence assumed as a supposed 

 cause. The impossibility of explaining the regularity by simple tidal 

 action would have fully justified such skepticism. 



But when we find that the lunar tabulations bring out such accordances 

 as I have already shown (Proc. Amer. Phil. Soc, x, 436 — 9, 523—37 ; 

 xi, 203; xii, 38—9, 178—90, 523—9, 556—9), while the Jovian influence, 

 although possibly greater in point of magnitude, is more questionable 

 and more easily overcome or hidden, I think we have good reason to con- 

 sider the fact of lunar influence as practically demonstrated, and to 

 hope, at no distant day, for a valuable extension of our weather-fore- 

 casts by means of that influence. 



Comparing the several sets of normals in these tables, by noting the 

 agreements or disagreements in the excess or deficiency of average rainfall 

 at corresponding periods, we find no marked evidence of resemblance in 

 the nine-years' groupings ; but in the twelve-year groups, corresponding 

 nearly to a Jovian year, there are eighteen agreements to twelve dis- 

 agreements, and there is a degree of resemblance in the aspect of the 

 plotted curves which it is difficult to believe accidental. A similar com- 

 parison shows a similarity of character between the curves at Philadel- 

 phia, Lisbon, San Francisco and Barbadoes, and an opposition between 

 each of them and the higher-latitude curve of Greenwich. 



CYCLICAL RAINFALL AT BARBADOES. 



By Pliny Earle Chase. 



{Bead before the American Philosophical Society, June l^th, 1874.) 



I confess to a feeling of some disappointment at the first results of my 

 examination of the lunar monthly rainfall at "Husband's" Station in 

 the island of Barbadoes. If I had no more satisfactory evidence of cyclical 

 regularity, and if further study had not enabled me to eliminate some of 



