522 Proceedings. 



Sir James Hector considered the presence of fluate of lime a valu- 

 able indication that the agencies which had produced deposits of metallic 

 ores had been in operation in the locality. Everything was tending to prove 

 the correctness of the surmise he had frequently ventured, that the north- 

 west district of Nelson would prove one of the richest mineral districts 

 in New Zealand. 



Third Meeting : 31st July, 1S89. 



Mr. A. de B. Brandon, President, in the chair. 



Neiu Member.—^. Percy Smith, F.E.G.S. 



Papers. — ^1. "On the Soaring of the Hawk — A possible 

 Eeason for Notched Wing-feathers," by T. W. Kirk, F.E.M.S. 

 (Transactions, p. 325.) 



Sir J. Hector said he considered Mr. Kirk's observations to be of 

 great interest. The question of how the soaring flight of birds was 

 mechanically maintained had long been a subject of discussion, and there 

 were several interesting papers in the " Transactions of the New Zealand 

 Institute " dealing with it. He had always held that the investigation 

 should be founded on the anatomy of the birds. jNIany years ago, with 

 Sir W. BuUer, he had made dissections of the muscular attachments of 

 the wing of the albatros, and at the time thought he had found evidence 

 of the existence of tendinous expansions from the brachial muscles that 

 could exercise a rotating influence on the quill-feathers, after the elbow- 

 and wrist-joints were locked in full extension. The extended arm of the 

 wing would then act as a sustaining parachute, while a slight " feather- 

 ing " movement of the primaries, acting with the leverage at a dis- 

 tance from the centre of gravity of tlie bird, would exercise a great 

 influence in controlling its direction of flight. Specimens of the albatros 

 preserved in spirit bad been sent Home, and submitted by Sir W. Buller 

 to competent authorities, however, and this view had not been sustained. 

 So far as he was aware, the mechanical effect of the interlocking of the 

 primaries, rendered possible by their peculiar emarginations, as described 

 by Mr. Kirk's paper, was certainly a novelty. 



The Hon. K. Pharazyn called attention to a series of pictures in the 

 Illustrated London News, taken from instantaneous photographs, showing 

 the rotary motion of the wing-feathers of birds in flight. He stated that 

 the motion varied in different parts of the wing, and he believed it quite 

 possible that in some species the peculiar motion mentioned by the 

 author did take place. 



j\lr. Kirk, in reply, said he did not enter upon the question of the 

 supposed rotary motion of the wing-coverts at all. And the amount of 

 rotary motion required in the primaries, supposing his idea to be cor- 

 rect, was very small — merely sufficient to allow the feathers to lock in 

 the manner indicated. He was aware that the structure of the terminal 

 joint would seem to preclude the possibility of a rotary motion of the 

 primaries ; but he believed that careful observations in the field and 

 laboratory, aided by experiments, would yet prove that it was possible for 

 the bird to alter the position of these feathers at will. 



2. Further Evidence re the Korotangi, or Stone Bird. 



{Transactions, p. 499.) 



Mr. Tregear said that he had no paper to read on the subject, but 

 that he had received some documents bearing on the question, and would 

 make some remarks thereon. He would first recall the main points of 



