
466 NATURE [JUNE 24, 1915 
history. I have been unable to find any tendency to | captured, so that the body of water flowing down 
return a second time to a marine life in our living 
river mussels.” 
In speaking of the changes taking place in the Baltic 
Sea, Mr. Findon remarked that the sea was ‘‘ becom- 
ing more shallow, and consequently the communica- 
tion with the North Sea between the Danish Islands is 
less free than formerly. On the other hand, the 
drainage of the marshes of Petrograd has allowed 
more fresh-water to flow into it; thus there is less 
influx of salt-water at high tides, and the Baltic is 
becoming brackish. Indeed, the northern portion is 
almost fresh, and fluviatile shellfish have invaded the 
open water. Many well-known species of the sea- 
shore, on the other hand, have held their ground, and 
we have the phenomenon of salt-water species, such as 
mussels, cockles, and tellens with a periwinkle, Lit- 
torina rudis, the estuarine Mya arenaria, or gaper, and 
a small univalve, Hydrobia balthica, living in fellow- 
ship with the river mussel Unio, two pond snails, 
Limnza and Bythinia, the fresh-water Neritina, and 
a small bivalve, Sphewrium. The assemblage is a 
remarkable one, considering the normal habitat of each 
of these species, and thus in the Baltic to-day the 
Lamarckian theory of modification to, but not by, 
environment, is well illustrated by these marine species, 
which are gradually changing their salt-water habitat 
for a fresh-water one.” 
A paper was read by Mr. Edward A. Martin on 
Brighton’s lost river, in which the gradual disappear- 
ance of this river, which at one time flowed out at 
the Steine Gap, was traced. The river must have 
been of some importance in prehistoric times, although 
in historical times its whole history is one of decadence 
and almost complete disappearance. From a con- 
sideration of other rivers on the south coast Mr. Martin 
endeavoured to build up a former condition of things, 
which enabled the old town of Brighthelmstone to be 
built on alluvial flats beneath the cliffs. 
“When the Brighton river was in its prime, there 
is every reason to think that its action was the same 
as that which now characterises other rivers on the 
south coast. The flow of the water would bring down 
with it large quantities of sediment, and bars would 
be produced at its entrance into the sea. As these 
increased, alluvial flats would be formed. This, of 
course, was in pre-history. There were no harbour 
commissioners to remove the bar. Man had no in- 
terest in it. It may have been before his time in these 
parts. A delta was in process of formation, and would 
no doubt have been perfected, had not a rival power 
interfered. The formation of the Brighton delta was 
influenced at all times by the tidal rise, and this would 
have been increased on the forcing of the strait of 
Dover. The river acting in a north to south direction, 
and the tides acting in a west to east direction, 
brought about a combination of forces which caused 
the alluvial drift to move in a more or less easterly 
direction. There is every reason to believe that some- 
where, a mile or more out at sea, the river was turned 
to the east by the tides, and that the river was bounded 
by an alluvial bank formed by the sediment brought 
down by the river, reinforced by the supply of gravel 
brought from the west, as it is now, by the tides. 
What has taken place at Shoreham, Newhaven, and 
Seaford, took place at Brighton, and I imagine that 
the Brighton river passed away towards the east below 
the cliffs for some distance, dropping its sediment on 
the way, before it was able to force and keep open its 
outlet into the sea. Lyell mentioned that in the reign 
of Elizabeth ‘the town was situated on that tract 
where the Chain Pier now extends into the sea.’ 
“Tn the course of centuries the river became deprived 
of its excavating power, and many of its feeders were 
NO. 2382, VOL. 95] 

became seriously lessened. The process was a slow 
one, but sooner or later the struggle with the tides 
proved an unequal one. Hitherto, all that the tides 
could do was to turn the river eastward and enclose 
it within a long, low-lying bank of shingle, and the 
denuding power of the wind and storm waves, raised 
on the shoulders of the tidal rise, was at a minimum. 
When the entrance of the considerable body of oppos- 
ing water from the valley was modified, and the influ- 
ence it possessed practically ceased, alluvium ceased 
to be deposited, and the denudation of the alluvial 
ground-covered flat and its destruction by the sea com- 
menced. This went on unceasingly, until the whole of 
the land beneath the cliffs was washed away. Mantell 
remarks that ‘the whole of the ancient town was 
situated on a spot now covered by the sands,’ whilst 
Lyell mentions that ‘ the sea has merely resumed its 
position at the base of the cliffs, the site of the old 
town having been a beach which had for ages been 
abandoned by the ocean.’ The old town had, as a 
matter of fact, been built on the alluvial flats which 
had been laid down by Brighton’s lost river.” 
Discussion on the origin of the Brighton Rubble- 
Drift Formation in the Kemp Town cliffs elicited the 
fact that in addition to the palzolith from the raised 
beach (now at the British Museum), another implement 
of Chellean form has been obtained from the raised 
beach at Slindon, near Arundel, West Sussex. 
Other papers read were by Prof. G. S. Boulger, on 
Kew : some notes on its connection with the history 
of botany; by Mr. A. Bonner, on the study of place- 
names; by Mr. A. W. Oke, on three Sussex worthies : 
Mantell, Robertson, and Jefferies; and by Mr. C. C 
Fagg, on regional surveys and local natural history 
societies. Excursions to points of interest in the dis- 
trict were made during the congress, which, in spite 
of many difficulties, was carried through in a very 
successful manner. 
OSMOTIC PRESSURE AND THE 
PROPERTIES OF SOLUTIONS. 
WO monographs dealing with the properties of 
solutions have recently been issued by the Car- 
negie Institution of Washington. The first, entitled 
‘““Osmotic Pressure of Aqueous Solutions,” is a report 
by H. N. Morse, on the investigations made in the 
chemical laboratory of the Johns Hopkins University 
during the years 1899-1913. This masterly investiga- 
tion, extended already over a period of fifteen years, 
has been recognised at once, and universally, as one 
of the classics of scientific literature. As the sub- 
stance of the investigation was originally issued in 
more than a score of papers, it is a great advantage 
to have the whole work summarised, corrected, and 
brought up to date by the author himself. The whole 
technique is now set out in a series of chapters deal- 
ing with the cells and manometer attachments; the 
manometers; the regulation of temperature; and the 
membranes. The fifth chapter contains a strong 
defence of the weight-normal system for solutions 
against criticisms and attacks that have been made 
upon it, arising mainly from the mistaken assumption 
that this method of working was the expression of 
some theoretical view of the nature of solutions or 
the mechanism of osmotic pressure. 
The opinion is emphatically put forward that a 
comprehensive equation for the osmotic pressures of 
solutions can only be reached by means of experi- 
ments, and that so many phenomena are involved 
that it will be impossible to predict the osmotic pres- 
sure of a solution unless the magnitude of some of 



