422 PHILOSOPHICAL TRANSACTIONS. [aNNO IjOj . 



crusade which was then in agitation. It will appear to any one who reads the 

 whole of his Iter, and is at all acquainted with the geography of the country, that 

 Giraldus (who was a native of Pembrokeshire) never was himself in these moun- 

 tains of Snowden; he had therefore only picked up this account, from some of 

 the inhabitants of the towns through which the archbishop passed, who them- 

 selves probably received it from mountaineers. There are few inhabitants of the 

 principality, who have ever been in this tract of mountains ; and Mr. B. who 

 had been in most parts of them, had always been informed, at his setting out, 

 that the roads were nearly impassable. On these occasions, he frequently in- 

 quired whether there was any such notion or tradition among the mountaineers, 

 with regard to monocular fish, and found, that it is supposed there are such in a 

 pool called Llyn y Cwn, which indeed he had never seen ; but, by the best ac- 

 counts, it is high up the Glyder mountain, which forms the opposite side of the 

 vale of Lanberris to Wyddva, or the highest part of Snowden. But on further 

 inquiry, he found no satisfactory confirmation of the matter. 



XXIV. An Observation of an Eclipse of the Sun at Newfoundland, August 5, 

 1766. By Mr. James Cook. Communicated by J. Bevis, M.D., F. R. S. p. 215. 

 Mr. Cook, a good mathematician, having been appointed by the lords commis- 

 sioners of the admiralty, to survey the sea-coasts of Newfoundland, Labrador, 

 &c. took with him a good apparatus of instruments, and among them a brass 

 telescopic quadrant made by Mr. John Bird. Being, on August 5, 17 66, at one 

 of the Burgeo islands near Cape Ray, latitude 47° 36' 19", the south-west ex- 

 tremity of Newfoundland, and having carefully rectified his quadrant, he waited 

 for the eclipse of the sun ; just a minute after the beginning of which, he ob- 

 served the zenith distance of the sun's upper limb 3 1° 57' 00"; and, allowing for 

 refraction and his semidiameter, the true zenith distance of the sun's centre 

 32° 13' 30'', whence he concluded the eclipse to have begun at o''4'" 48' ap- 

 parent time, and by a like process to have ended at 3*^ 45"' 26' apparent time. 

 There were 3 several observers, with good telescopes, who all agreed as to the 

 moments of beginning and ending. Mr. Cook having communicated his ob- 

 servation to me, I showed it to Mr. George Witchell, who told me he had a very 

 exact observation of the same eclipse, taken at Oxford by the Rev. Mr. Hornsby ; 

 and he would compute, from the comparison, the difference of longitude of the 

 places of observation, making due allowance for the effect of parallax, and the 

 earth's prolate spheroidal figure ; and he has since given me the following result : 



5" 23" 59' beginn. at Oxford. 7" 7" i' end at Oxford. 



46 48 beginn. at Borgeo Isles 3 39 14 end at Borgeo Isles. 



4 37 11 3 27 51 



— 51 59 effect of parallax, &c. + 17 35 effect of parallax, 8rc. 



3 45 22 diff, of meridians. 3 45 26 diff. of meridians. 



