King. — On New Zealand Mean Time. 441 



Mr. C. W. Adams, New Zealand Geodesical Surveyor, at the 

 Survey Department's observatory which then stood on the site 

 at Mount Cook afterwards taken for the prison buildings, by 

 another series of careful telegraphic exchanges arrived at a 

 result almost identical with that of Mr. Kussell and Arch- 

 deacon Stock, allowance, of course, being made for the differ- 

 ence (1-21 s. :;: ) between the longitudes of Mount Cook 

 Observatory and Wellington Observatory, as derived from 

 triangulation. (The respective personal equations of Mr. 

 Eussell and Mr. Adams were tested and taken into account in 

 the final examination of their work.) These three determina- 

 tions compare as follows : — 



Difference of Longitude, Sydney and Wellington. 



Wellington Observa- 

 tory East of 

 Sydney Observatory. 



H. M. 3. 



Stokes's chronometric determination ... 1 34 15 - 28 



Eussell and Stock's telegraphic determination 1 34 15 - 99 

 Eussell and Adams's „ „ 1 34 15-77 



There was another chronometric determination — viz., by 

 Captain G. S. Nares, of H.M.S. " Challenger" (see his memo- 

 randum to Dr. Hector, printed in vol. vii. of the "Transactions 

 of the New Zealand Institute," 1874, p. 502). This gave the 

 meridian distance of Wellington Observatory as 1 h. 34 m. 

 17 - 23s. E. of Sydney Observatory; but, as Captain Nares 

 himself pointed out, his result was not so trustworthy as that 

 of Captain Stokes, as an interval of twenty-one days elapsed 

 between the "Challenger's" observations at Sydney and 

 Wellington, whereas Captain Stokes is supposed to have run 

 his distance directly from Sydney to Wellington, and thus to 

 have secured his observations at the two ports within a less 

 interval of time. Captain Nares's determination was there- 

 fore not accepted. 



The following table shows the several longitudes for Wel- 

 lington Observatory resulting from these determinations, with 

 the changes rendered necessary from time to time by the cor- 

 rections made in the longitude of Sydney : — 



* Mount Cook Observatory was east of Wellington Observatory 

 2097"2 links = l - 21s., as is shown in a copy of a departmental memo- 

 randum kindly furnished to me by Mr. Marchant, Surveyor-General. 



