✨ Survey Observations
OTAGO
PROVINCIAL GOVERNMENT GAZETTE.
PUBLISHED BY AUTHORITY.
All Public Notifications which appear in this Gazette, with any Official Signature thereto annexed are to be considered as Official Communications made to those Persons to whom they may relate, and are to be obeyed accordingly.
JOHN HYDE HARRIS, Deputy Superintendent.
Vol. V.] WEDNESDAY, JULY 23, 1862. [No. 197.
RECONNAISSANCE SURVEY
OF
THE WANAKA AND HAWEA LAKE DISTRICT.
Dunedin, 17th Feb., 1862.
To J. T. Thomson, Esq.,
Chief Surveyor.
SIR,—I have the honor to submit for your inspection the result of observations for latitude, longitude, and true meridian, obtained at Lindis Peak; at Mount Nicholas (west side of Wakatipu Lake); and at Mount York (situate about four miles east of where the Waiau River issues from the lower Te Anau Lake). In reference to the longitudes, it will be necessary to mention, that daily comparison of the chronometers showed, that not only have they a different rate when carried from what they have when let alone, but also that that rate is not uniform, varying backwards and forwards from one to two seconds per day. It appeared to me that the only way of detecting the amount of this variation for each chronometer, was, to take observations at the meridians, both going and returning; I accordingly did so, and found that the rate of Barraud's chronometer was fast, but losing, while that of Shepherd's was slow, but gaining. The rate deduced from 1st January to 3rd February gives to Shepherd's chronometer a rate differing 1.2 seconds per day from what the interval, 7th to 25th January, gives; whereas the rate of Barraud's chronometer, as deduced from the two intervals, does not show any change of rate till the third decimal place. Again, by deducing the rate from the intervals 18th-28th Dec., and 3rd-11th Feb., the rate of Barraud is found to be .75 of a second less per day than during the rest of the journey; while that of Shepherd, for the same intervals, is intermediate between its other two rates. Considering, then, that Barraud's chronometer has had only two rates differing .75 of a second, while Shepherd's chronometer had 3, with a maximum difference of 1.2 seconds per day, I have used the former chronometer only, in determining the differences of longitude between meridians. Although the chronometers were carried with the utmost care, all the observations obtained with a clear sky, and the rates frequently verified, yet I would not claim any higher value for the longitudinal determinations than a near approximation; for the chronometers were always affected more or less when carried over high elevations. This may be attributed to the zig-zag course one has to take at such places, and also to the change of temperature. The uniformity of rate for different intervals, and the comparatively small change of rate, when it did take place, show that compensation of errors takes place to some extent; but still there
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Otago Provincial Gazette 1862, No 197
✨ LLM interpretation of page content
🗺️ Reconnaissance Survey of Wanaka and Hawea Lake District
🗺️ Lands, Settlement & Survey17 February 1862
Survey, Observations, Latitude, Longitude, Wanaka, Hawea, Lindis Peak, Mount Nicholas, Mount York
- J. T. Thomson (Esquire), Chief Surveyor
- JOHN HYDE HARRIS, Deputy Superintendent