524 Proceedings. 
swallow, he doubted very much whether, if brought here, it could be induced to remain 
with us, the migratory instinct being very powerful. 
9. Dr. Hector exhibited a telephone and two forms of the microphone, made by Mr. 
John Kebbell, and explained the principles of their construction, The microphones were 
placed on the lecture table, and connected by wire laid to different parts of the Museum 
with several telephones in circuit; the marvellous transmission of faint sounds was readily 
illustrated. The experiments performed were to some extent marred by the extreme sensi- 
tiveness of Mie aaa as the irregular noises produced by the rustling movements 
t 
ly overpowered the sounds that were intended to be transmitted, 
is sounds of iex voice, wt tuning forks, and slight friction of the sounding boards of the 
microphones were, however, rendered distinctly audible throughout the complete circuit. 
A cordial vote of thanks was passed to Mr. Kebbell for his kindness in exhibiting to 
ihe Society these interesting inventions. 
FovnarH Merrine. 31st August, 1878. 
T. Kirk, F.L.S., President, in the chair. 
New Members.—G. Morton, J. R. W. Cook, William Berry. 
Additions to the library were laid on the table, and Dr. Hector drew attention to the 
following fishes lately added to the Museum collection, viz., Holocanthus arcuatus, Mono- 
canthus hippocrepis, and Serranus trutta (the latter being a new species) from Fiji, 
colleeted and presented by Lord Hervey Phipps; also, Ceratodus forsteri, from Queens- 
land, presented by Sir C. Wyville Thompson. 
1. ** On some of the Causes which operate in Shingle-bearing Rivers in 
the Determination of their Courses and in the Formation of Plains," by 
J. P. Maxwell, A.I.C.E. 
ABSTRACT. 
The author contended that the Canterbury Plains were formed by the 
action of the rivers in conveying shingle from the ranges and depositing it 
in their lower courses and at their mouths; that continual changes in the 
courses of the streams were effected by these deposits, thus giving rise to 
the distribution of material over extended areas; that this process was still 
going on, and that the elevation and extension of the plains would pro- 
ceed while the supply of detritus from the ranges continued; that the features 
were largely modified by the action of the sea in distributing the shingle 
along the coast-line; that examination of the river beds showed that they 
are sometimes elevated along the middle lines of their length, and that 
streams flowed on either side, cutting notch-like channels in the older plain 
formation ; that the evidence of these channels on both sides of the river 
beds is a sufficient. refutation of the theory of the supposed effect of the 
influence of the earth’s rotation in causing erosion on one side only. 
Dr. Hector said he agreed with the views of the author as far as they went, but he 
thought that the formation of the great fan-like deposits of shingle that go to make up 
