550 PROCEEDINGS OF SECTION E. 



equal to 17-02 seconds of time, was communicated to Captain Hutclii- 

 son in a memorandum from Mr. A. B. Cooper, Deputy Surveyor- 

 General, dated November 6th, 1868. 



CAPE WILLOUGHBY. 

 During the year 1850 Mr. J. T. Manton, under instructions of the 

 then recently formed Trinity House (Marine Board), determined the 

 longitude of Cape Willoughby Lighthouse, Kangaroo Island, by 13 

 lunar observations, with the following results : — One, taken in August, 

 gave 9hrs. 12min. 39secs. ; three in October gave 9hrs, 12min. 283ecs. ; 

 and nine in November gave 9hrs. 12min. 33secs. ; the mathematical 

 mean adopted being 9hrs. 12min. 32secs. = 138° 08' 00", which is as 

 nearly correct as can be calculated. 



ADELAIDE OBSERVATORY. 



About 10 years after the Adelaide Observatory was established, 

 its longitude v/as ascertained, with a near approach to accuracy, by 

 telegraphic time signals with Melbourne and Sydney Observatories, 

 the positions of which had been independently fixed by astronomical 

 observation. The longitude then adopted and printed on official 

 memo, forms Avas 9hrs. Mmin. 21-4sec. = 138° 35' 19"-5. 



A special feature of time signals consists in observing the astro- 

 nomical local time at the precise moment of transmitting and receiving 

 signals, and eliminating personal errors. The telegraph operator's 

 part is so well done that any set of signals may usually be depended 

 upon to one-tenth of a second of time ; but the astronomer's part — 

 unless he be an expert — may contain an error for the set approaching 

 one second of time. Sir Charles Todd gave a very clear explanation 

 of the method in use in an address to the Institute of Surveyors, Novem- 

 ber 2nd, 1888, printed by that body in its annual report. 



TAventy-four years ago, in conjunction with the, Government 

 Astronomers of Victoria and New South Wales, and Captain DarAvin, 

 R.E., the Government Astronomer of this State, Sir Charles Todd, 

 completed from Singapore a telegraphic determination from GreenAA^ch, 

 ma Palmerston, to Adelaide, Melbourne, and Sydney ; obtaining there- 

 by for the longitude of Adelaide 9hrs. 14min. 26-30secs. a 138° 35' 04"-5. 

 This result was verified last year under direction of Professor 0. Klotz, 

 from America, by trans-Pacific cable to Sydney. Professor Klotz's 

 determination places Sydney 85ft. further east than the published 

 longitude, which afiects Adelaide to the same extent. 



WESTERN BOUNDARY OF SOUTH AUSTRALIA. 

 Parliamentary Paper, No. 137 of 1867, shoAvs that an effort 

 was made that year to locate the position of the 129th meridian of 

 longitude forming the Avestern boundary of this State. Captain Douglas, 

 R.N., President of the Marine Board, erected an obelisk near the coast, 

 about seven miles this side of Eucla, which purported to mark a point 

 on the boundary line, but is now supposed to be half a mile or more 



