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Table of Contents
Astronomical and Meteorological Workers in New South Wales
Admiral Phillip Parker King
Sir Thomas MacDougall Brisbane
Dr. Charles Stargard Rumker
P. E. De Strzelecki
Captain J. C. Wickham
Rev. W. B. Clarke, M.A.
Rev. A. Glennie
E. C. Close
Sir William Macarthur
S. H. Officer
William Stanley Jevons
Establishment of Meteorological Observatories
Votes and Proceedings, N.S.W., 1848.
The astronomical work of Capt. Flinders, Commander of H.M.S. "Investigator," during her exploring voyage to Australia, was important. On the 19th January, 1801, Matthew Flinders was appointed Lieutenant in Command of H.M.S. "Investigator" (heretofore known as the "Xenophon") for her exploring voyage to Australia. Mr. John Crossley was appointed astronomer, but owing to ill-health was obliged to leave the ship at the Cape of Good Hope, and his duty was assumed by Flinders in addition to his other duties, and probably a better observer could not have been found. For all the principal places on the south coast of Australia her determined the longitude by direct lunar observations, and without giving details, which may be found in the "Voyage to Terra Australis" (Vol. I., 1814, App. p. 259), it may be stated that he made the longitude of Dawes' Point (called Cattle Point) 10h. 4m. 47.3s. east of Greenwich; the recent value found by, cable is 10h. 4m. 49.5s., a wonderfully accurate result considering the instruments of those days! He mentions that the Spanish Admiral D'Espenosa found the longitude of the same place to be 10h. 4m. 51s. These are remarkable results, and well worth recording as the earliest careful attempts to find the longitude of Sydney; there was far less uncertainty about it than Flinders himself thought, but a recognition of the care and ability which he brought to bear upon his work is one of the greatest honours which we can pay to his memory. He made the latitude 33° 51' 456'', but there is not now, unfortunately, at least so far as I can learn, any clue to the exact part of Cattle Point on which he set up his instruments the latitude of the present Observatory is 33° 51' 41'' and that of the extreme point (Dawes' Point) is 33° 51' 21'', so that he was very little out.
Although, not bearing directly upon astronomy or meteorology in Australia, it is important to note that during his work on the Australian coast Flinders discovered the cause of the local attraction of the ship on the compass, and the account of it is best given in his own words (loc. cit. p. 1, Preface): "A variety of observations with the compass had shewn the magnetic needle to differ from itself, sometimes as much as 6° or even 7° in or very near the same place, and the differences seemed to be subject to regular laws but it was so extraordinary in the present state of navigation that they should not have been before discovered, and a mode of preventing or correcting them ascertained, that my deductions and almost the facts were distrusted; and in the first construction of the charts I had feared to deviate much from the usual practice. Applications was now made to the Admiralty for experiments to be tried with the compass on board different ships; and the results in five cases being conformable to one of the three laws before deduced, which alone was susceptible of proof in England, the whole were adopted without reserve, and the variations and bearings throughout the voyage underwent a systematic correction." Such is the simple story of the discovery of one of the most important facts connected with the use of the compass at sea that has ever been made. It is usual in books upon magnetism to say that the fact of the ship's attraction on the compass was first observed by Mr. Males, the Astronomer of Captain Cook, when he was sailing along the coast of New Holland; but if that be true it is strange the Admiralty knew nothing about it, and that in the Navy generally it was an unknown fact; certain it is, that Flinders was the first to see and trace the fact, and work out the laws which govern it. Flinders himself shews (loc. cit., Vol. II., App. p. 512) that Mr. Males had observed the fact that magnetic bearings on ship board were unreliable, but he attributed it to faults in the compasses and imperfections in construction, and it is quite evident that he did not see the real cause, viz.: the ship's magnetism, which Flinders did and worked at it until he found the law of change, viz.: that it was in proportion to the lines of the angles of deviation, due to the ship's position and could thus correct every observation. Flinders communicated his discovery in a paper read before the Royal Society, (Phil. Trans., 1805, p. 186.)
Barlow very soon after proposed that an iron plate should be put below the compass in wooden ships. Airy, the Astronomer Royal, proposed a steel magnet below the compass, but neither suggestion was of much use, and the discussion going on upon the subject led to the Rev. Dr. Scoresby's voyage to Australia, with the object of working out a true theory of correction, with the ship's attraction, a method still in general use. And finally to Sir William Thompson's method of corrects the ship's magnetism by a series of magnets placed below the compass.
People in Bright Sparcs - Dawes, William; Flinders, Matthew; Russell, Henry Chamberlain
© Online Edition Australian Science and Technology Heritage Centre and Bureau of Meteorology 2001
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