﻿THE CRATER LAKES OF TAAL VOLCANO. 



By Raymond Foss Bacon. 

 (From the Chemical Laboratory, Bureau of Science, Manila, P. I.) 



About a year ago I published the results of analyses made on the 

 nature of the interesting lakes in the crater of Taal volcano. 1 The water 

 examined at that time was brought to the laboratory in January, 1906. 

 Another expedition from this laboratory visited the volcano early in 

 March. 1907, and it is the purpose of this paper to record the data then 

 collected. During the intervening period no marked eruptions of the 

 volcano had occurred, but it was nevertheless found that quite evident 

 changes had taken place in the crater area; these are shown by a 

 comparison of the photographs taken two years ago, one year ago and 

 recently. (See Pis. II to VI.) The yellow lake, which existed in 

 1906 and of the water of which an analysis was given in the former 

 communication, has entirely disappeared ; even the lake bottom had been 

 completely filled up so that there now is nothing to indicate that such 

 a lake ever existed. Other places where small, red and green lakes were 

 seen by the previous expedition, were also dry, although in most cases 

 the lake beds were still sharply defined, the former bottom was covered 

 with a thin, red or yellow crust which would not support a man, the 

 stratum underneath being a soft, wet mud. The green lake has dimin- 

 ished in area, so that now access is possible to the two fumaroles at its 

 south end; these are each about 10 meters in diameter at the surface, 

 sloping conically to an opening into the earth of about 0.5 meter. From 

 one of these blowholes a very large amount of steam not under great 

 pressure is continually rising; from the other, much hot gas containing 

 a large quantity of sulphur dioxide is issuing under considerable pressure 

 and with a deafening, roaring noise. (See PL VI, fig. 3.) The two 

 vents, which are not more than 15 meters apart, are evidently independent 

 and not connected at any place near the surface. 



To the southeast of the green lake, a basin is found in the present 

 active crater, surrounded on three sides by high, perpendicular, rock 

 walls, the least distance to the surface of the water being about 30 

 meters. The water of this lake is in constant, violent ebullition and 



1 This Journal I, 433. 



115 



