88 PRACTICAL ASTRONOMY IN TASMANIA. 



owing to the fact that on account of her valuable position in 

 the far south, in this matter of finding tne sun's distance, 

 as in many other astronomical respects, she was at once seen 

 to be a place where the necessary astronomical observations 

 ought certainly to be made. But the Astronomer Royal of 

 England said "No,"' for we do not know her longitude suffi- 

 ciently accurately — and that was true, we did not. America 

 came to the rescue. "Why not," said America, "find the 

 longitude accurately?" So they came, found the longitude, 

 observed the transit, and w^ent. 



I will not preach here of the importance of knowing the 

 longitude. I will only say that it is a very complicated mat- 

 ter to obtain it, a matter requiring costly instruments, much 

 knowledge, and much painful training, and the result is 

 that we know where we are on this planet. 



The result with regard to longitude is that for all time 

 we know the following fact : - — We know that a certain piece 

 of masonry (at present in existence in the Barrack Square) 

 is 9ni. 25.66s. enst of the centre of tbe transit instrument 

 m Melbourne. The Melbourne longitude is itself in doubt, 

 and I will now read you an extract from, a letter I have re- 

 ceived from Mr. Baracchi, the Victorian Government As- 

 tronomer, on that point : — 



"(1st) The present adopted longitudes of Sydney and 

 Melbourne are: — Sydney, lOh. 4m. 49.44s.; Mel- 

 bourne, 9h. 39m. 54.00s. 



"The Nautical Almanac still persists in giving the 

 values adopted by Ellery Russell, and Todd, in 

 their longitude report of 1886. I suppose, as the 

 differences are small, and the values by no means 

 final, it is considered unnecessary to introduce 

 changes at present. In the American Ephemeris 

 the value 9h. 39m. 54.00s. is adopted for Mel- 

 bourne, and lOh. 4m. 49.54s. for Sydney. 



"When it will be time to introduce changes in our 

 longitudes, my values of 1895 (Report 

 A.A.A.S., 1895, pp. 185-208) will have to be further 

 reduced, owing to the smaller values obtained for 

 Madras later. I adopted for Madras 5h. 20m. 

 59.275s. The new and latest determination, gives 

 5h. 20m. 59.113s. Adding this to former results, 

 with double weight, we obtain 5h. 20m. 59.167s., 

 which, in my opinion is, at present, the best avail- 

 able value for the longitude of Madras, and, as no 

 further measures have been made east of Madras 

 since 1888, the longitudes of Sydney and Mel- 

 bourne may be considered to be — Sydney, lOh. 4m. 



