VOL. 



LXI.] 



PHILOSOPHICAL TRANSACTIONS. 



177 



disputably exist, and we had a good opportunity to observe it, for every wished 

 for favourable circumstance attended the whole of that day, without one single 

 impediment, excepting the heat, which was intolerable: the thermometer, which 

 hung by the clock, and was exposed to the sun as we were, was one time as high 

 as 119°. The breadth of the penumbra appeared to me, to be nearly equal to 

 4- of Venus's semidiameter. 



3. Transit of Venus by Dr. Solander, with a 3-feet reflecting telescope. 

 First external contact plainly convex, a wavering haze seen some 



seconds before 



App, time. 



Ingress, light seen glimmering under Venus 21'' 43™ 28* 



9 's free from the 0's limb 21 44 2 



$ 's true limb out 3 31 4q 



9 's atmosphere out 3 32 13 



4. Observations of the transit of Venus, made by Mr. Charles Green, with 

 DoUond's micrometer fitted to a reflecting telescope of 2-feet focus, gave on the 

 day of the transit, for the diameter of Venus, 54". Q, on a medium of the whole, 

 and that of the sun 31' 27".4. At these observations the thermometer stood 

 at 113°. 



5. Observations on the transit of Venus, June 3, 1769, by Dollond's micro- 

 meter fitted to a reflecting telescope of 18 inches focus, by Capt James Cook. 

 The mean of all these give 56".4 for the diameter of Venus. 



Observations on the Dipping Needle. 

 Place where. 



Dip of the north 

 or south point. 



In Funchal Bay, dip of n. end of needle 



Crossing the line in long. 30° 18' w. of Greenwich 



77' 18' 



26 to 28 If. point 



At sea in lat. 52° 54' s. and long. 63° 10' w. . . 



Good Success Bay in Straits Le Maire 



On board the ship at anchor in the above bay . . 



At sea in lat. 60° 4' s. long. 74° 10' w 



Ditto ditto, 36 49 s. ditto 111 54 w 



Ditto ditto, 30 46 s. ditto 125 28 w 



Ditto ditto, 18 25 s- ditto 140 51 w 



George's island, lat. 17° 29' s. long. 149° 34' w. 



63 

 68 

 65 

 65 

 65 

 64 

 30 

 30 



8. point 



51 ditto 

 ditto 



17 ditto 



52 ditto 

 25 ditto 



ditto 

 43 ditto 



N. B. Each of the above observations is the mean of 10, 12, or more; with 

 the face of the instrument turned alternately east and west: those made at sea 

 are a little dubious on account of the motion of the ship; but, by means of a 

 swinging table we had made to set the compass on, we could, in a tolerable 

 smooth sea, be certain of the dip to a degree, or at the most 2, by taking the 

 mean of a great number of trials. 



Lastly are given a set of observations on the tides at George's Island, by which 



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