6 PKOCEEDI2?G3 OF THE GEOLOGICAL SOCIETY. 



5 Inverness Terrace, AV., and The Cliff, Marazion ; Henry Arthur 

 Spalding, Esc}., Geraldton, Western Australia ; Umfreville Percy 

 Swinburne, Esq., Capheaton Hall, iS'ewcastle-on-Tyne ; and William 

 Koberts Thomas, Esq., Uranium Mines, Grampound Road, Cornwall, 

 were' proposed as Eellows of the Society. 



The List of Donations to the Library was read. 



The following names of Fellows of the Society were read out 

 for the first time, in conformity with the Bye-laws, Section YI. 

 Article 5, in consequence of the non-payment of their arrears of 

 contributions : — R. N. Boyd, Esq. ; E. B. Henderson, Esq. 



The appointment of Mr. L. Belinfante as Assistant- Secretary was 

 confirmed. 



The following communications were read : — 



1. " Account of an Experimental Investigation of the Law that 

 Limits the Action of Elowing Streams." By R. D. Oldham, Esq., 

 A.R.S.M., E.G.S., Deputy Superintendent of the Geological Survey 

 of India. 



[Abstract.] 



The Author brings forward evidence, derived from experiments, in 

 support of the views expressed in a paper submitted to the Society 

 in 1888. His apparatus consisted of a sloping trough, through 

 which various amounts of water containing definite percentages of 

 sand could be sent. The lower end of the trough issued on to a 

 semicircular platform. 



In experiments with the trough at a slope of 1 in 20, and with 

 the same supply of sand in each case, the resulting slopes after sand 

 had accumulated in the trough were as follows: — AVith one part of sand 

 to 42 of water, a slope of 1 in 40 ; with 1 of sand to 28 of water, 

 1 in 20 ; and with I of sand to 14 of water, 1 in 13*3. These 

 slopes were obtained when a stable condition had been arrived at, 

 in which the water was just able to transport its burden. By 

 changing the supply of water from one to another of these values 

 the corresponding slopes were obtained. 



On the fan formed on the horizontal platform variations in the 

 water-supply did not produce nearly so marked an effect as in the 

 confined channel, and the slope varied considerably in difierent 

 directions. 



After a time a channel was cut back from the margin of the fan, 

 and its sand was swept forward and deposited as a secondary fan in 

 front of the first ; and as the channel grew, it cut back into the 

 reach above, and this in turn cut back towards the head of the fans, 

 and sometimes into the trough. In some cases other secondary fans 

 were formed on the margin of the main fan, but the apparatus was 

 not large enough for further formations. The general slope of the 



