406 Miss F. E. Cave-Browne-Cave. Influence of the [Dec. 20,, 



3. It seemed desirable to determine the intervals for which the corre- 

 lation between each pair of stations is greatest, and also the values of 

 these maxima. After some consideration, the curve 



log?/ = 



was selected as likely to give a reasonable interpolation result,* the 

 axis of y being that of the correlation, and x being the interval, in 

 days, between the readings, counted as positive when the observation 

 is taken later at the more easterly station in each case. The curves 

 are not intended to represent the complete correlation data, but they 

 have been used as convenient empirical methods to find in position and 

 magnitude the maximum ordinates. For this reason only five correla- 

 tions were used for calculating each curve, namely, those given in rows 

 5 to 9 of Table I, and rows 4 'to 8 of Table II. The following curves 

 were determined : 



WILMINGTON AND HALIFAX. 



..Summer, 18791888: 



_ 0-477451 + 0-161608z - 0'062808z 2 - 0-058772aj 8 + 0-014994Z 4 . 

 Maximum ordinate : 0*3877 at x = 0*7275, i.e., 17 '46 hours. 

 Summer, 18891898: 



= - 0-524516 + 0-175661Z - 0-122239z 2 - OO40868a? + 0-012096**. 

 Maximum ordinate : 0*3386 at x = 0*5862, i.e., 14-07 hours. 

 Winter, 18791888 : 

 logio v 



= - 0-592740 + 0*647374^ - 0*300470z 2 - -054822z 3 + 0*021968o* 4 . 



Maximum ordinate : 0-5272 at x = 0'9553, i.e., 22'92 hours. 

 Winter, 18891898: 



logio y 



= - 0-634964 + 0-6155142 - 0-258629z 2 - 0'073287o* 3 + 0'025021a 4 . 



Maximum ordinate : 0'4721 at x = 0-9674, i.e., 23'22 hours. 



ST. HELENA AND CAPE TOWN. 

 Summer, 18931898: 

 logio y 



= - 0-346171 + 0-063222z - 0'064491 2 - O'Ol 1993z 3 + 0-006497&*. 

 Maximum ordinate: 0*4660 at x = 0-4518, i.e., 10-84 hours. 

 Winter, 18931898: 



= - 0-400900 + 0-1 19333x - 0'039277 2 - 0-022393z 3 + 0-006580z 4 . 

 Maximum ordinate : 0'4596 at x = 0-9994, i.e., 23'986 hours. 

 * The suggestion is due to Mr. W. Palin Elderton. 



