178 



PHILOSOPHICAL TRANSACTIONS. 



[anno 177 !• 



it is inferred by the astronomer royal, that the mean height of the sides is about 

 10 inches, and the greatest height scarcely exceeds one foot, in the middle of 

 this wide extended ocean ; which falls far short of what might have been expected 

 from physical principles. The cause of this remarkable difference deserves fur- 

 ther inquiry. The time of high water also appears to precede the moon's passing 

 the meridian by 45 minutes at a medium, and the time of low water to precede 

 the same, by 6^ 31"". But the mean difference of high and low water, should 

 be 6'' 12"", which subtracted from S** SI", leaves 19™, by which the time of 

 high water should precede the moon's passing the meridian; the mean of this 

 and 45" is S^'", by which the time of high water precedes the moon's passing 

 the meridian, by a medium of all the observations. The times of high and low 

 water seem to be subject to great irregularity on particular days; no doubt owing 

 to the small rise of the water, and the smallness of its force in consequence, 

 which renders it more liable to be disturbed by the action of the winds and other 

 causes; part of the irregularity may be attributed to the difficulty of observing 

 the time of the flood or ebb, with any degree of certainty. N. Maskelyne. 



N. B. The island here named King George's Island, is called by the natives 

 Ota-heite, by which name it will henceforth be called, the name of King 

 George's Island having been given before to another island in lat. 14 s. disco- 

 vered by Commodore Byron. 



*^* Mr. Green having died at sea in the passage home from Batavia, all the 

 astronomical and other observations were partly arranged by Capt. Cook, and 

 partly by the astronomer royal, from the original manuscripts, and calculated by 

 the latter. 



XLIV. Variation of the Compass, as observed on board the Endeavour Bark, 

 in a Voyage round the World. Communicated by Lieut. James Cook. p. 422. 

 These observations were taken from the latter part of 1768, to the middle of 

 177 1: so that the columns of variation may, near enough, be supposed to 

 answer to the middle year 1770. 



Latit. 



North 



29" 



Longit. 



West 



7' 16" 50' 



Pico Tcnerift, N. 18 

 Distance 140 mile*. 



26 

 25 

 20 

 19 

 18 

 15 



50 

 20 

 56 

 33 

 38 



40 



17 

 18 

 20 

 20 

 21 

 22 



12 

 50 

 40 

 50 

 t) 

 



