THERMOMETRICAL OBSERVATIONS. 213 



Alls* 2d Equal alliluJfs of the Sun* ..' '• 



°' ' A. M. 8" 9' 35". P. M. 3" 46' 56". 



Prepared to obferve an immerfion of tiia iftfatellite of 

 Tf. — At 13'' 43' a fmall cloud began to obfcure the moon, 

 but 1i and his fatellites continued very bright till about 

 13'' 44' -26'' when the ifl fatellite began to lofe its luftre ; 

 At 13'' 44' 35" the cloud which appeared over the moon, 

 extended itfelt almoft inilantaneoully over the whole hemil- 

 phcre, and obfcured the ftars and planets. 



5th. 



Equal altitudes of the Sun. 

 A. M. 8" 6' 41". P. M. 3'> 48' 19" 



gfjj Equal altitudes of the Sun. 



A. M. -J^ si' 19"- P- ^I- 3" S6' 



9th. 



£OTc>y?ffn of the 2d fatellite of If obferved at 13'' 13' 9". 

 The planet and his fatellites middling bright. Magnifying 

 power of the telefcope 1 20. 



On the 6th and 9th of this month, at the dirtance of 9 miles and ninety 

 perches from the firft rranfit ftation B, and diftant from tlie point D Plate VI. 

 10 miles and 5 perches, equal altitudes of « Delphini were taken in the fame 

 manner, as already related with Arilurus, to determine the direftion of our 

 arc, which on a bafe of 212.5 perches, was 31 inches fouth of the prime 

 vertical, which is equal to an angle of 2' ■^i"'6'''. — This angle ought to 

 liave been but 2' 13" 59'", the difference o' 17" 7" was therei'cre the error 

 of the arc to the fouth. Now fuppofe this error to have been gradually 

 accumulating, which is very probable, it would at the diftance of 9 miles 

 and 90 perches, (the fpace between the tranfi: ftations , have carried the 

 arc about 2 feet too far to the fouth : But the tranfit at the diftance of 9 

 miles and 90 perches from the firft i^ation, ought to have been 2 feet and 

 7 inches north of the parallel, the difference therefore of 7 inclies is the 

 diftance of the tranfit to the north of the parallel at its fecond .ftatioQ, and 

 which is. included in the offsets for the fecond arc to the termination of 18 

 miles, and 118 perclies fr<jm tlie point D. — On the 9th another arc 

 for 10 miles was kid off, making an angle of 2' 36" 45'" with the prime 

 vertical. The bafe was 212.5 perches eaft, and the perpendicular 32 

 inches north from tlie aperture of tlie lantern. 



J 2 th Sqttat ahiiudes of the Sun. 



A.M. 8" 6' 43'.' P.M. 3'- 47' 7". 



Vol. V. F f 15th. 



* The equal-altitudes of the fun, and his paffage over the meridian with 

 the thermonietrical obfervations when they occur, are entered according to 

 the civil account, the odiers according to the mode of aftronomers. 



