78 ON THE INCREASING MAGNITUDE OF ETA ARGUS. 



say definitely when it took place, but it seems probable that the 

 period is about 80 years ; it is about 40 years since its maximum, 

 and carrying this backwards, the observations since 1800 and 

 the two previous ones in 1751 and 1677, will fit into places on the 

 curve, 1751 by Lacaille at the Cape, 1677 by Halley at St. Helena. 

 It must, however, not be forgotten that this star when near its 

 maximum was subject to remarkable fluctuations in brilliance, 

 and it seems probable that it would present the same character 

 at minimum, and such has been shewn by observation • but the 

 present increase in brilliance is so considerable, that I think there 

 can be no doubt that the minimum is past, and that Eta Argus 

 will again be a brilliant star in the heavens. 



NOTES ON SOME MINERALS AND MINERAL 



LOCALITIES IN THE NORTHERN DISTRICTS 



OF NEW SOUTH WALES. 



(With one Plate.) 

 By D. A. Porter, Tamworth. 



[Read before the Royal Society of N.S.W., June 6, 1888-2 



In a paper read before your Society on 5th Nov., 1884, I had 

 the pleasure of offering a few observations on " Some Minerals 

 and Mineral Localities in the Northern Districts of New South 

 Wales," and I purpose in this paper to continue the same subject, 

 as I think it is very desirable that every mineral locality in the 

 Colony, so far as known, should be noted, so that they may be 

 easily discovered by those who, in the future, may desire to 

 submit them to further examination. The notes contained in 

 this paper are the result of personal examination of the various 

 minerals and localities referred to herein. 



Gold. 

 As gold is so widely distributed throughout the northern 

 districts of this Colony, and as all the localities in which it occurs 

 are well known and catalogued, I purpose only mentioning it 

 in instances where something unusual is connected with its 

 occurrence, such as its association in alluvial or matrix with other 

 minerals or metals. 



