352 



On the influence of the Moon 



[July, 



the moon, and the heights of the tides of the ocean on the same days. 

 The only table I could refer to was that given us by Mr. Noton, 

 (Jour. As. Soc. May, 1833,) of the tides in Bombay harbour, which an- 

 swered tolerably well, as Bombay, as well as Calcutta, has considerable 

 north latitude. The heights of the tides, day and night, both at change 

 and full, are given there, as well as for three days after, and three days 

 before, the day of change and full. I took, therefore, the average 

 height of the tides in the seven days about each new and full moon, 

 and compared them together. The first comparison was the day (or 

 superior) tide of the new moon, and the day or inferior tide of the full 

 moon. It was as follows : 



Ratio of day tide, New Moon, 



New Moon, 





Full Moon, 



to night tide 



, Full Moon 



ft. 



in. 







ft. 



in. 



ft. in. 



12 



11 Feb. 



2. 



.. 15 2 Jan. 17. 



12 



11 



: 17 



13 



5 March 



2. 



.. 15 1 Feb. 16. 



13 



5 



16 1 



14 



3 April 



1. 



.. 15 March 16. 



14 



3 



16 



* 15 



3 April 



30. 



. . 14 5 April 15. * 15 



3 



: 15 4 



15 



9 May 



30. 



. . 14 5 May 14. 



15 



9 



: 13 10 



16 



5 June 



28. 



.. 15 3 June 13. 



16 



5 



: 14 1 



16 



5 July 



27. 



. . 14 3 July 13. 



16 



5 



: 12 9 



16 



1 Aug. 



26. 



.. 14 6 Aug. 11. 



16 



1 



13 



15 



6 Sept. 



24. 



.. .14 5 Sept. 11. 



15 



6 



13 1 



14 



11 Oct. 



24. 



.. 14 3 Oct. 10. 



14 



11 



13 11 



* 14 



3 Nov. 



22. 



.. 14 3 Nov. 8. * 



14 



3 : 



15 



13 



3 Dec. 



22. 



.. 14 4 Dec. 8. 



13 



3 



15 10 



It will be observed, that in the winter season, when the new moon 

 has great southern declination, and the full moon has great northern 

 declination, (or, in other words,) comes near the zenith of the place in 

 question (Bombay), then the new-moon tide is not so high as the full- 

 moon tide ; but, in the summer season, when the declinations are rever- 

 sed, then are the ratios of the tides reversed also. I have marked with 

 an asterisk the places where the ratios change. But we must here 

 notice a remarkable anomaly in the lunar theory. The ratios we have 

 observed above ought only to hold with direct or superior tides of both 

 new and full moon, the reverse ought to hold with respect to the infe- 

 rior tides of both. For instance, if the declination of the moon were 

 20° south, and consequently the vertex of her superior tide in 20° 

 south latitude, the vertex of the inferior or opposite tide ought to be in 

 20° north latitude. So that in places to the north of the equator, as 

 Bombay and Calcutta, the inferior tide would be very large when the 

 superior tide was very small. Thus at Bombay, in winter, the night, 

 or inferior tide, of new moon, ought to be very large ; the day, or infe- 

 rior tide, of full moon, very small : but on comparing them together, we 

 find the reverse. 



