392 Mr. V. N. Nene. On a Method of Tracing 



waves of five weekly period of the continuous curve from the numbers 

 corresponding to the interrupted curve for the periods from 31st to 

 37th week of 1848, and 13th to 23rd week of 1849 is worth noticing. 

 It should also be noticed that the irregular movements that exist in 

 the interrupted curve for the period from 31st week of 1850 to 15th 

 week of 1851, also exist in the continuous line curve. 



53. Let us now combine the result by taking 36-J days as an aver- 

 age duration of the period to get an average range or amplitude of 

 the period, as shown in paragraph 39. 



Table showing the variations of 36-J-day period for several groups 

 of periods and for the whole period. 



jNumber of points in the 

 curve (7 "3 days for a point). 



0. 



1. 



2. 



3. 



4. 



Second group of 13 periods . . 

 Third group of 12 periods . . . 

 Combined above three groups 1 



- -113 



- -041 



- -018 



- -048 



- -048 



- -016 



- -034 

 + -016 



- -on 



- -012 



+ -114 

 + -018 

 + "028 



+ "041 



+ -036 



+ -081 

 + -034 

 + -004 



+ -033 



+ -035 



- -058 

 + -016 



- -019 



- -013 



- -013 





These results are curved in figures 7 to 11 respectively. 

 It must be mentioned here that the ranges which we see in these 



7tt 



sin 7 



36J 



results are not exact, but enlarged by our process and 



= nearly 2*7, is the extent to which our results are enlarged. 



But we must also notice that the facts that the period is not an 

 integral number of weeks, that our method of combination is in 

 consequence rather rough, and that the number of points in the curve 

 is too small, tend to reduce the range of the period. If the process 

 had been applied to the continuous daily means instead of to weekly 

 means the results would have been of a larger and equal amplitude of 

 several groups of the period. 



54. The writer feels himself under great obligation to his superior, 

 C. Chambers, Esq., F.R.S., Superintendent of the Bombay Observa- 

 tory, for the warm interest he took in carefully reading this tract, and 

 in giving here and there some very valuable suggestions. 



