[ 24 ] 



From the weftcrn edge of the cloud iffued a luminous arc 

 parallel to the horizon, perfectly well defined, extending exadiy 

 to the northern meridian ; it was about 30' broad, white, and 

 ended in a blunted termination. On it were two parhelia ; the 

 neareft to the fun difplaying the prifmatic colours ; the remote 

 one white, and both ill defined. In a fhort time the cloud had 

 pafTed off, and fhewed the luminous almicantar, reaching perfed 

 to the true fun. While things were thus fituated, I meafured 

 with an accurate fextant the diftances of the parhelia ; I found 

 the coloured one 260, the remoter one 90°, from the true fun. 

 Juft as I had done this, a new and prifmatic circle furrounded 

 the fun, immediately within the prifmatic parhelion. And now 

 another coloured parhelion appeared on the eaftern board. The 

 fextant with its face up and down, exadlly meafured this and the 

 former at the original diftance of 26° ; the luminous almicantar 

 ftill remaining perfed. In about ten or twelve minutes, whitifh 

 hazy clouds came on, and obfcured all thefe uncommon appear- 

 ances. I did not obferve that the atmofpherical phasnomena 

 before or after were at all uncommon. The wind a light breeze 

 at S. S. W. Bar. 29,6 rifing. Thermometer 55°. 



Pla'elll ^ ^''■* reprefents the fouth meridian. 



F'g- I- N. M. north meridian. 



P. P. the prifmatic circle, with two prifmatic funs or parhelia, 

 at 26° diftance on each fide the true fun. 

 W. the white parhelion, at 90° diftance from the true fun. 

 L. A. the luminous almicantar. 

 And H O. the horizon. 



