1^78.] Ohservations in tlie OiLlf of Cutch. lO 



of minimum squares. Corrections were then computed for the daily 

 variations of the atmospheric influences on the sea-level, and were applied 

 to the values of height resulting from the previous investigations of the 

 short-period tides. Finally, the differences between the heights thus 

 determined and those actually observed were taken as the data for calcu- 

 lating the influence of each of the long-period tides. 



The evaluation of the atmospheric influences gave the following factors 

 for changes of sea-level due to a barometric pressure of one inch, and to 

 north and east winds travelling with a velocity of 10 miles per hour : — 



At Okha. At Hanstal. 



Barometric pressure ... ... -f 0" 356 feet — 0*4!38 feet. 



North Wind — 0-191 „ —0-262 „ 



East Wind +0-161 „ +0087 „ 



These results are not satisfactory ; the height of the sea-level at Okha 

 appears to increase with an increase of barometric pressure, which is scarcely 

 possible. It happens that at this station the changes of pressure occurred, 

 as a rule, simultaneously with the changes of wind ; and thus it is im- 

 possible to determine the separate effect of each, otherwise than by some 

 arbitrary method of treatment. The observations will therefore be again 

 analyzed, with a view to ascertaining whether they may not be made to 

 yield more consistent results. Meanwhile, the values of the atmospheric 

 factors already obtained must be considered to be only aj^proximate, giving 

 fairly accurate results when employed collectively but not individually. 



Of the constants for the long-period tides the following values have 

 been computed for the stations of Okha and Hanstal, after the elimination 

 of atmospheric influences, by employing the preliminary values of the factors 

 which are given in the preceding paragraph. At Nawanar sufficient obser- 

 vations are not forthcoming for the evaluation of either the atmospheric 

 or the long-period tides. 



Long-period tides, and their Constants. 

 (a — to) Lunar monthly elliptic tide, 



2 or Lunar fortnightly declinational tide, 

 2 (cr — r]) Luni- solar synodic fortnightly tide, 

 7] Solar annual elliptic tide, 

 2 7j Solar semi-annual declinational tide, 

 Okha. Hanstal. 



Feet. ° Tide. Feet. ° 



Ji = 0-058, € = 311-38 (o- — w) i2=0-107, € = 14*17 



„ 0070,,, 52-73 2o- „ 0142, „ 4574 



„ 0-136, „ 249-19 2 (o- — >?) „ 0163, „ 1176 



„ 0-162,,, 311 7] „ 0024, „ 195-32 



„ 0-121, „ 144-75 2rj „ 0090, „ 150-38 



7 



