146 
capital in which the session is held, have 
to undertake a journey of 500 or 600 miles, 
or even 1,200 miles, as in the case of those 
who attend from New Zealand, or who, liv- 
ing in Brisbane, attend a meeting in Ade- 
laide, or vice versa. 
These very long distances are a great dis- 
advantage to the Association, for they 
mean a considerable expenditure of time 
and money, and many are thereby de- 
barred from attending. It is largely due 
to these causes, as well as to the limited 
number of working members, that we have 
had most reluctantly to substitute biennial 
for annual sessions. If we had more work- 
ing members, and I think we should get 
them if there were local scientific societies 
scattered through the Colonies, we should 
be able to resume our annual meetings, and 
before very long we ought to be able to hold 
our sessions in towns like Ballaarat, Bath- 
urst, Bendigo, Goulburn and Newcastle. 
For the formation of local societies it is 
not necessary to start with a large mem- 
bership—the Royal Society of London be- 
gan with five or six only. 
It is, however, very gratifying, under the 
circumstances, and with our comparatively 
limited population, that our meetings are as 
well attended and successful as they are. 
A. LIVERSIDGE. 
THE RED COLOR OF THE SALT LAKES IN 
THE WADI NATROUN. 
In an article published in the Zoolog. An- 
zeiger* I have given a report on the biology 
of the Natron Valley, the Wadi Natroun, 
in the Libyan desert, about 170 kilometers 
from Cairo. It seems that my remarks 
concerning the red color of the water of the 
salt lakes of the valley have interested read- 
ers of the article. I, therefore, wish to add 
here some researches I was able to make on 
the same subject owing to the kindness of 
* Das Wadi Natroun in der libyschen Wiiste und 
seine niedern Thiere. Bd. 22, p. 53-61, 1899. 
SCIENCE. 
[N.S. Vou. X. No. 240 
Mr. Prochaska, head of the chemical sur- 
vey of the soda company. 
When I came to the Natron Valley the 
red water of the lakes excited at once my 
curiosity, and I tried to ascertain the reason 
for the redness of the liquid. Most people 
to whom I spoke about the matter told me 
that Artemia lives in the lakes, and that the 
red color of this Crustacean is communi- 
cated to the water. During my stay in the 
Wadi the Artemia salina was not to be 
seen, the animal appearing only at cer- 
tain periods of the year. It is impos- 
sible to believe that the colored mass of 
these small creatures is sufficient to stain 
such immense quantities of water as the 
Wadi Natroun lakes. These lakes, about 
fourteen in number, lie rather close to each 
other and extend over a space of about 40 
kilometers. No number of Artemia salina 
would be great enough to give the water 
the deep purple color which it has. If 
there were frogs in the lakes and those 
frogs were red, and some one should say 
that the red color of the water came from 
the red color of the Amphibia, this explana- 
tion, I think, would not be much inferior 
to the Artemia theory. Besides Artemia 
there are other red animals in the lakes. I 
obtained, for example, a red culicid larva. 
This shows that animals living in the water 
may take the color from it, and not the 
water from the red animals. Finally, Ar- 
temia salina disappears in the lakes for the 
greater part of the year without causing a 
change in the coloration of the water. 
But, if it is not Artemia salina, what is it 
that gives the red color to the water? In 
my investigations I treated the red water 
with different chemicals, among them acetic 
acid. When the acid is poured into the 
red water a powerful development of car- 
bonic acid takes place, and at the same time 
a red soft mass rises to the surface of the 
liquid, while the latter loses more and more 
of its color. From a large quantity of 
