404 



INDEX. 



Page 

 INTRODUCTION : 



Voyage, and Names of Observers 405 



Site at Observatory Bay 405 



The Transit-Clock ...... . . 406 



The Transit Instrument 406 



Micrometer Screw and Intervals of Wires 407 



Zero of Collimation 407 



Level Error 407 



Error of Azimuth 408 



Stars used for Clock-Error 408 



Relative Personal Equations of the Observers 4O9 



The Altazimuth Instrument 410 



Runs of Micrometers of Vertical Circle of Altazimuth 411 



Stars for Co-latitude 411 



Refractions, Thermometers, Barometer, Adopted Latitude 412 



Runs of Micrometer of the Horizontal Circle 413 



Horizontal Intervals of the Vertical Wires 414 



Corrections for Collimation 414 



Error of Level of Horizontal Axis 415 



References of Altazimuth Clock to Transit-Clock 415 



Determination of Zero of Azimuth 415 



Computation of Tabular Azimuth of the Moon on two assumptions of Longitude ... 416 



Longitude of Observatory Bay from Meridional Observations of the Moon .... 417 



Longitude from observed Azimuths of the Moon 418 



Longitude from the Occultation of a Star by the Moon 418 



Longitude derived from Professor Newcomb's determination of the Longitude of Molloy 



Point 419 



Longitude derived from Dr. Auwers' determination of the Longitude of Betsy Cove . . 421 



Adopted Longitude of Observatory Bay 421 



Observations of the Transit of Venus by the Rev. S. J. Perry 422 



Observations of the Transit of Venus by the Rev. W. Sidgreaves 423 



Equations thence deduced 425 



OBSERVATIONS IN TABULAR ARRANGEMENT : 



Table I. Collimation of the Transit Instrument 428 



Table II. Error of level of the Transit Instrument 430 



Table III. Azimuth Errors 436 



Tables IV. and V. (Abstract) Transits of Stars and of the Moon, and Inferred R.A. of 



the Moon's Limb at Transit 440 



Table VI. Longitude of Observatory Bay, from the Meridional Transits of the Moon . 443 

 Table VII. Abstract of determinations of Longitude of Observatory Bay from observed 



Azimuths of the Moon's Limbs 445 



Plate XVI to face 405 



