JUNE. 



The usual monthly meeting of the Royal Society was held on Monday, 

 June 11, under the presidency of the Hon. C, H. Grant, M.L.C. 



The Secretary (Mr. A. Morton) tabled a work entitled " A voyage 

 towards the South Pole performed in the years 1822-24, containing an 

 examination of the Antarctic Sea to the 74deg. of latitude," by Jaines 

 Weddell, Esq., presented by the Rev. J. B. VV. Woollnough, M.A., 

 M.H.A.; also " Papers and Proceedings of the Royal Society of 

 Tasmania for 1893." The Secretary drew attention to an innovation in 

 the latter volume, consisting of the inclusion of a form of bequest on 

 the lines adopted by many leading scientific societies. 



MERIDIAN OBSERVATIONS WITH THE HOBART TRANSIT INSTRUMENTS. 



Mr. Kingsmill said : The object of my paper is to bring under your 

 notice a piece of astronomical work done at the Hobart Observatory, 

 in the first instance by myself, and afterwards more completely be 

 Captain Oust, of the Dirt. This work was the determination of the 

 meridian of the Hobart transit instrument by means of star observa- 

 tions taken with the instrument itself. The American astronomers 

 determined a meridian with great accuracy when they came here on 

 the transit of Venus expedition, and it would be possible to draw 

 a parallel to it by offsets, as the Hobart Observatory is only 57ft. west 

 of their meridian. Put this method would be far less accurate than 

 the determination of a fresh meridian by independent observations. 

 There is a meridian mark for the Hobart transit instrument near Mount 

 Nelson, just above the rifle range, and a little to the east of it. A 

 stone something like a milestone has been erected in brickwork with a 

 crosscut in it to indicate the exact meridian. When I came to the 

 Observatory 1 was told that the cross was wrong, and that the true 

 meridian was close to the eastern edge of the stone, but there was no 

 record of the exact amount of the error. To obtain the exact local 

 time it is necessary to find out all the errors of the instrument. It is 

 by a number of small corrections that accuracy is obtained. However, 

 this error appeared to require a pretty large correction. In December, 

 1893, I took some observations of the Southern Pole Star and Octantes 

 which,satistied me that the true meridian was clear of the stone alto- 

 gether and to the east of it. It happened that there was an iron- 

 dropper in a wire fence very nearly in the right position, and I used 

 this as a temporary mark. It is perhaps not generally known that the 

 Australasians have a pole star of their own considerably nearer to the 

 Pole than the celebrated North Pole Star. But, unfortunately, we 

 cannot see it with the naked eye. Still it can be seen with a telescope 

 of very small power, and it affords an easy and accurate method of 

 determining the meridian. Several other methods were adopted as a 

 cheek, as follow : — The instrument was first carefully levelled and 

 collimated, then set in a vertical position to observe a star passing 

 directly overhead. It happens that in the latitude of Hobart several 

 stars pass almost exactly overhead. One of these and Phoenicia are only 

 6sec. from the vertical. By observing the transit of a vertical star the 

 exact time can be obtained with an instrument not in the true meridian. 

 In that position the azimuth error has no effect. Having determined 

 the true time in this way, Octantes, the pole star, was next observed, 

 and followed with the middle wire of the instrument until the time he 

 was due for his transit. Having by this and other methods made sure 

 of the result I wrote to the late Chief Secretary (Hon. Adya Douglas), 

 pointing out the necessity of having the transit instrument exactly in 

 the line of the true meridian ; that I had found by a number of star 

 observations that the meridian mark was considerably out of the line, 

 and that it would be necessary to shift the stone ; that in its present 



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