APPENDIX. 



peatedly put in motion, it was found to flop, till a muflcet 

 bullet and a half was added to the weight, which was 

 found fufficient to keep it in motion ; when it was thus 

 found to continue its vibration, it wasjocked by the 

 trigger at 60". The equatorial inflrument was fet up 

 on a bafis of folid rock, and being in this cafe to be ufed 

 only as a tranllt inftrument, no attempt was made to adjuft 

 it either to the latitude or meridian of the place; but the 

 azimuth and equatorial circles being truely levelled, the 

 telefcope was diredled towards the fun, and fo elevated 

 that it fliould pafs as near as poflible through the middle 

 of the field. The inflrument being thus prepared, the 

 Weft limb of the fun was obferved to touch the Eaft fide 

 of the vertical wire in the telefcope at 5*^ 19' 28" in the 

 afternoon, by the watch ; and at the fame inftant the pen- 

 dulum was unlocked, and kept vibrating till after the fun 

 had completed its revolution, and its Weft limb was 

 again feen to touch the fame fide of the vertical wire. 

 From the vertical pofition of the wire and the 

 time of the day, the fun's motion had a degree of 

 obliquity with refpe£l to the wire, which muft occafion 

 its diameter to take a longer time in pafling than if it 

 crofted the wire at right angles: this pofition of the 

 wire, together with the change of the fun's declina- 

 tion, prolong the time of the fun's coming again to the 

 wire ; fo that there was an interval of twenty-four hours, 

 forty-nine feconds and a half, from the time that the fun's 

 limb touched the wire on the fixteenth day of July, to 



A a 2 the 



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