THE WATERS OF THE CRATER LAKES OF TAAL VOLCANO 
WITH A NOTE ON SOME PHENOMENA 
OF RADIO-ACTIVITY. 
+ By R. F. Bacon. 
(From the Chemical Division, Bureau of Seience. ) 
The crater of Taal Volcano, in the Province of Batangas, central 
Luzon, has in it two very remarkable pools. They are known as the 
Green Lake and the Yellow Lake, respectively, owing to the color of their 
waters. About 2 liters of water was obtained from each of these by the | 
members of an expedition from this laboratory, who visited the voleano ; 
during the present dry season (January, 1906). 
The voleano consists of a series of elevations containing, among others, a large 
crater about 3 miles long and 2 miles wide, rising from the waters of Lake Taal. 
Within this is a small crater, at present active in the solfotaric stage, and the 
ash cones of several dormant ones. There are also three lakes within the boun- 
daries of the large extinct crater; two of these have been mentioned above, the 
other is in the crater of the present active cone and it was not accessible at the 
time of this, expedition. The water of this lake is at a boiling temperature and 
large volumes of steam continually rise from its surface; the temperature of the 
other two, at the time of the visit, was only a little above that of the air (about 
38° C.). These lakes are described as being boiling hot by former investigators 
and there is little doubt but that they may change very markedly from season 
to season. 
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These waters were considered to be deserving of investigati6n because, 
as they possibly had such free access to the depths of the earth, they 
might be of an extraordinary composition. The analyses proved that, 
while the concentration and acidity of the waters were remarkably high, 
rare or unusual elements could not be detected in the amount of liquid 
available, neither were we able to demonstrate that the samples were 
radio-active, but this lack of radio-activity may be due to the fact that 
they had been standing for about four weeks before it was possible to 
make the necessary tests. A rock sample obtained from the yellow pool 
was not radio-active. ‘The determinations were made by dissolving a 
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