XXlll 



5. From the Rev, George Brown, C.M.Z.S. A Native Drum and 



13 Spears, from New Bi'itain, Specimens of the Shell from 

 which the " Shell money" of New Britain is made. 



6. From Mr. T. H. Bromfield. A young Porcupine Ant-eater (Echidna 



setosa). 



7. From Mr. R. M. Johnston, F.L.S. Specimen of a species of Sea 



Bream {Girella trimspidata), from Southport. In reference to this 

 specimen, Mr. Johnston remarks : — " This interesting fish was 

 obtained by me from a dealer, and is locally known to the boat- 

 men as ' The Sweep.' Hitherto this species was either not known 

 to exist in Tasmania, or it may have been confounded Avith some 

 other member of the ' Sea Bream ' family. Like nearly all of this 

 group, it is an excellent fish for the table, and, in my opinion, 

 when in good condition, is superior to the 'Sand MxyWet {Mugii 

 cephalotus), and almost rivals the ' Trumpeter ' [Latris heca- 

 teia) in flavour. I have temporarily, with hesitation, placed it 

 under Quoy Gaimard's G. ti'icuspidata. It is in some respects 

 intermediate between the latter species and O. simplex, Richardson ; 

 but while it more nearly agrees with the latter in lateral and trans- 

 verse series of scales, and in relative length of head, yet its 

 peculiar, well marked, tricuspidate teeth ally it more closely with 

 the former. The two species named are, however, very closely 

 allied." 

 Presentations to Library : — 



From the Ballarat School of Mines, two copies of the Annual Report 

 for 1880. 



From His Excellency the President, diagrams prepared by him to illus- 

 trate a lecture on the Southern Skies, delivered on the 17th ult., to be 

 made use of hereafter for any instructional purpose the Council may 

 think fit. Symons, British Rainfall, 1879. A file of the Waratah Weekly 

 I^ews, in manuscript. Portrait of Mr. W. Spottiswoode, LL.D., President 

 (if the Royal Society. Magnetical and Meteorological Observations taken 

 in North America, by Captain Lefroy, R.A., and Sir John Richardson, 

 C.B., M.D., 1855. Agricultural Report of Bermuda. 



The President exhibited a number of harmonic curves drawn by 

 Donkiu's Harmonograph. This instrument is described in the Proceed- 

 ings of the Royal Society for 1874. The mechanical construction of 

 it is such that a finely pointed glass pen, following the motions of a 

 pendulum, or of a regularly oscillating crank, traces an endless line on 

 a sheet of paper which is itself in motion under the influence of another 

 crank or pendulum. Some of the curves were produced with pendu- 

 lums, and some by wheel-work. 



In this instrument one or both of the pendulums may be made to 

 revolve either in a circle or in an ellipse. The result is to produce an end- 

 less variety of beautiful figures. 



The attention of the Fellows was particularly called to the remarkable 

 fact that whenever the ratio of the times of vibration, or of vibration and 

 rotation, is one which corresponds to a definite interval in music, say thirds, 

 fifths, octaves, the result is a Bgure symmetrical and pleasing to the eye, 

 as the result of the two notes is harmony to the ear, and whenever the 

 ratio of the times is not a musical interval, the result is an uupleasing 

 figure, as it would be a discord in music. This was illustrated by many 

 examples. 



Mr. R. M. Johnston observed tliat the Harmonograph bore a slight re- 

 semblance to instruments, made by some machinery manufacturers, which 

 produced similar curves. There was also a form of harmonics produced 

 upon films of soap. In this instrument (the " Phoneidoscope") when true 

 fifths, or any other harmonic intervals are put together, bubble rings 

 are developed ; and if two persons sang together into the instrument at an 



