Chase.] 



438 



[June. 



It may thus be seen that, notwithstanding the complete veil- 

 ing of all the disturbances ivhich may he due to the moon's vari- 

 able distance and declination, there was a marked tendency to in- 

 crease at quadrature and to decrease at syzygy, both in the amount 

 of rain and in the number of rainy days. This tendency, 

 which becomes evident even in the majority of the five-years' 

 groupings, is uniformly shown in all the groups of ten years, 

 twenty years, and forty years, as well as in the number of 

 rainy days and in the number of heavy rains during the entire 



period. 



In a future communication I propose to discuss the obser- 

 vations at the Pennsylvania Hospital, which demonstrate the ex- 

 istence of similar tides at Philadelphia. The forty years' aggre- 

 gates (1825 to 1864, inclusive, at each station) exhibit the 

 following ratios of weekly rainfall : 



"Week of new moon, . 

 " first quarter, 

 " full moon, . 

 " last quarter, 



Surrey. 



98.2 

 103.1 



97.4 

 101.4 



Philadelphia. 



97.6 

 100.3 



95.8 

 106.3 



The tide is so strongly marked at Mussoorie, on the south- 

 ern range of the Himalaya Mountains, as to be strikingly shown 



