^.[^' 



88 



MATHEMATICAL and 



"i 



S' O, 34 



crva- 



And as, both by the Phihulelpbia cind Nornton obfcrvations, the longitude of the PhUadcl 

 phiaohfcrvatory, weft of Greenwich, is - - - S^- °'' 3S" 



The longitude of Lewis obfcrvatory Wek of Greenwich is in time 

 Or, in degrees and parts of the equator the langitudc of Lewis obfe: 



tm-y weft of Greenwich is - - - - 75^. 8/ 30"^ 



And its latitude as aUove - - - - 38. 46. 3^,3 North. 



For the advantage of navigation, we alfo took the courfcs and diftances frona our obfervatory 

 to the Provincial light-houfc near the Cape; and on reducing the work, we find the light-houle 

 north of our obfcrvatory 182,83 perches,--=a9",8; and caft of the time y44pcrchos=-y. i6'',8.. 



The latitude of the light^icufe, is - - . 38"- 47'- ^^'»1^ North. 



Andjtslongitudc, weft of Greenwich - - 75- 5- I3>* 



I now proceed to give an aceount of the remainder of 

 our obfcTvations. The 2d of the month we had feveral 

 good correfponding ahitudes of the Sun for fetting our 



time-piece. 



- The 3d being the tranfit-day, was as fine in every re- 

 fpe£t for our obfervation, as we could defire; the air calm, 

 and not a cloud in view. We ^ ' "" ' 



ponding altitudes of the Sun, taken in feafon, not to in- 

 terrupt the obfervation of the tranfit. 



About 1 2 o'clock we direded our telefcopes to the Sun, 

 determined to keep it conftantly in the field, till the con- 

 tads fhould be paft; and in the mean time wc fet our boys 

 (whom we had tutored for that purpofe) to count the fe- 

 conds by the clock, each boy counting one minute alter- 

 nately, leaft they fliould be wearied, and not perform it 

 with fufficient exadncfs. During the whole a pcrfon was 

 flandin^ by to overlook them, calling out each minute as 

 it elapfed, and noting it down. 



We had agreed with each other to attend to our tele- 

 fcopes one minute by turns, until about 7 or 8 minutes 

 before the expeded time, leaf! by too fteady attention, we 

 fhould impair our fight, and difable ourfelvcs from dif- 

 cerning the contad clearly. I had left my telefcope the 

 minute preceding the contad, intending to apply myfclf 



fleadily to it before the minute was fully elapfed; and not 

 to quit it again until the contad occurred. When the 

 48th fecond was called, I applied myfelf to the telefcope, 

 and by the time three feconds more were elapfed, I per- 

 ceived on that part of the Sun's limb, where 1 had expcded 



the 





