316 C. F, LASERON. 
velocity with which the electrons are projected from the 
hot surface. If this equation holds, on the assumption 
previously stated, we may deduce from the curve in figure 
1, that the velocity with which electrons are projected 
from glowing carbon varies from 1°5 x 10° centimetres per 
second at 3375 absolute to 2°5 x 10° centimetres per second 
at 3690° absolute. Ina similar way, from the result pre- 
viously given, a lower limit to the velocity with which 
electrons are projected from the Nernst filament may be 
calculated as 3 x 10’ centimetres per second. 
THE SEDIMENTARY ROCKS OF THE LOWER 
SHOALHAVEN RIVER. 
By CHARLES F’. LASERON. 
(Communicated by R. T. BAKER, F.L.S.) 
[Read before the Royal Society of N. S. Wales, December 2, 1908.] 
Introduction.—The following paper comprises the main 
features of geological interest noted in the course of several 
excursions made to the district within the last four years. 
As the river for some distance above Nowra is very difficult 
of access, considerable labour was experienced in exploiting 
it. But owing tothe kindness of one of the local residents, 
Mr. Robert Condie, who has assisted me on every occasion, 
I have been able to examine its course nearly to its junc- 
tion with its tributary, the Kangaroo River. Two camping 
expeditions were undertaken to this part, the boat with 
outfit and provisions being hauled up the rapids, which 
above Burrier are very common. The results of the pre- 
vious expeditions were briefly reviewed in the Australian 
