PREFACE. 



J- HE principal instruments in the Observatory at Paramatta are, 



A 5^-feet transit by Troughton. 



A 2-feet mural circle by the same. 



A 16-inch repeating circle by Reichenbach. 



A 3j-feet telescope with equatorial motion and wire micrometer by Banks. 



Two instruments for observing the variation and dip of the magnetic needle. 



The observations made with these instruments were planned with particular 

 respect to the place of the Observatory, and confined to what could be done 

 in the southern hemisphere alone. 



The first are magnetic observations. After these follows the geographical 

 position of the Observatory. Observations of latitude in the southern hemi- 

 sphere could best prove whether the difference usually found between the 

 results derived from stars north of the zenith and those derived from stars 

 south of the zenith, arise from local causes or from imperfections of the instru- 

 ments. In the reductions of these observations, I have partly made use of the 

 formula given by Bohnenberger in his " Geographische Ortsbestimmung," § 1 53. 

 The repeating circle has been in constant use for twenty years, and the nonius 

 of the smaller circle could not be made to close sufficiently to the greater 

 circle. I ascribe it to this cause that the latitudes deduced from some of the 

 observations made with this instrument deviate rather from the truth, the 

 greater part of them having moreover been made without an assistant. The 

 observations made alternately direct and by reflection show on the other hand 

 great consistency ; and as the results of these agree with the mean of the ob- 

 servations made with the former instrument on northern and southern stars, 

 there is no doubt of this being the true latitude. 



I might have rejected those observations with the repeating circle that de- 



