115 



Jena, of optical principles involved in the phenomena of 

 microscopic vision and their application to the construction of 

 the microscope. Dr. Whittell explained Dr Abbe's interpre- 

 tation of the manner in which the microscopic image is formed, 

 and of the appearance of certain details in this image, which 

 he shows to be due to the diffractive influence of the internal 

 structural constitution of the object examined upon rays of 

 light transmitted through it. 



Oedixaky Meeting, ArausT 1, 1882. 



Mr. D. B. Adamsox in the chair. 



Donations to the Library since last meeting were announced. 



Professor E. Tate, E.G.S., produced some specimens of a 

 substance, long known to have existed on the south side of 

 Kangaroo Island, which had been analyzed by Mr. Dixon, of 

 Kew South Wales, and pronounced by him to be a species of 

 pitch, which Professor Tate believed to be a waif from some 

 wrecked vessel, and was a very good Stockholm pitch. Some 

 resin had been forwarded from Eowler's Bay by Mrs. Ann 

 Eichards, and some beeswax and guttapercha had been found 

 by himself at the Head of the Australian Bight ; and at Eucla, 

 these led to the conclusion that some ship laden with chandlers' 

 stores had been wrecked on the coast. 



A specimen of some black mineral was forwarded under the 

 impression that it was coal, and a statement accompanied it 

 that the sender had submitted it to the Surveyor-General, who 

 could not state what it was, and a large block of land had been 

 taken up under the mineral regulations, with the idea that a 

 coal mine existed there. Professor Tate had proved the sub- 

 stance to be calc spar, coloured with carbonaceous matter. 



Mr. H. Chandler, of the Peake, forwarded a number of 

 specimens from that neighbourhood, consisting of haematite, 

 naturally-baked clay polished on one side, some red ochre, 

 hemisphere of agglutinated sand, common opal, quartz and 

 micaceous iron said to contain gold (from the Peake), micaceous 

 iron, tourmaline. 



Mr. HoGAETH sent specimens from a well-sinking 260 feet 

 deep, on the Mombra Station, near Mount Browne, on the 

 frontier of 'New South Wales, containing almost solid masses 

 of iron pyrites and shells, which Professor Tate referred to the 

 Jurassic genus Aucella. 



Professor Tate then read a paper, contributed by Baron 

 Perdiuand von Mueller, upon " Some additional South Austra- 

 lian Acacias." 



A paper by Mr. Gtavix Scotjlar, Corresponding Member, was 



