768 The Island of Dominica. [ November, 
which showed but little decomposition on the surface. Varying 
temperature, ranging from 85° C. to boiling point, was observed, 
while the water of the creek measured 68° C. But a few yards 
to the right, a narrow gully ran off from the creek, ending 
abruptly in a vertical wall, the lower portions of which were com- 
posed of trachyte. In the latter an almost circular opening, about 
two feet in diameter, led to regions unknown. Standing in front of 
this opening a regular pulsation within was observed. So far as 
could be seen; it was the mouth of a somewhat extended cavity 
` into which water rushed simultaneously, at nearly regular inter-_ 
vals, from the two sides parallel with the trend of the ravine. If a 
comparison be attempted, the total effect might be likened to the 
noise produced by a ship’s engine, accompanied by a similar 
though slighter tremor. Four pulsations occurred’ on an average 
during every seven seconds, and the fifth ejected a large mass of 
water through the opening. This main “spring” of Wotten Waven 
must therefore be regarded as a geyser. On account of the slip- 
pery character of the rocks and the imminent risk of being 
scalded, the temperature could not be obtained at the moment of 
emission. As the water flowed off it measured 98° C. Besides 
this large geyser, numerous small ones occur here, all, however, 
sending their water in lateral directions, not vertically. In addition 
to the rock openings ejecting water, there were many from which 
steam issued. Sometimes this was not visible at the immediate 
mouth and it became a matter of discrimination as to the selec- 
tion of standing places. Taking the temperature of several of 
-these jets, we found a maximum of 102° C. Noticeable is the 
total absence of sulphuretted hydrogen. While at the Soufreurs 
all the silver we carried with us almost instantly turned black, 
we could here find no point where bright coins would be at all 
affected. : 
` Although in a general way the sources of heat are due to the 
= same causes at Wotten Waven as at the Soufreurs, some differ- 
ences were found. Decomposition is the main factor, but in this 
_ instance pyrite is not the material most violently affected. Small 
quantities of the mineral certainly occur, and it is quite possible 
that its presence in larger proportion may originally have initiated 
the process of chemical changes. At this locality the trachytes 
contain a large percentage of soda feldspar (oligoclase). This is 
rapidly decomposing, and by the chemical reaction itself, as well 
