Description of a Lake of Sulphuric Acid, 197 
and the result of the war was the almost total annihilation 
of the population of the province. 
Bagnia-Vangni is entirely isolated from all the other in- 
habited parts of the island of Java: in order to arrive at it 
from Pannaroukan, we must traverse a forest twenty-four 
leagues in length, by a single foot-path two feet broad. 
Upon the whole route there are only two small villages 
with ten or twelve houses in each: these serve for halting- 
places for travellers, who are lodged in miserable cara- 
vanseras kept up at the expense of the chiefs of these vil- 
lages. We also meet with the traces of some other smaller 
villages or dessas ; but the inhabitants have been forced to 
abandon them on account of the tigers, which not only 
carry off their cattle but attack the villagers themselves. 
The isolated situation cf Bagnia- Vangni, and the difficulty 
of quitting it clandestinely, (for the tigers render it unsafe for 
single individuals to travel through it,) induced the Dutch 
East India Company to make it a place of exile for Indian 
malefactors; who are there employed in the cultivation of 
pepper and coffee. The latter production is superior to that 
of any other part of Java. 
During a residence of two months in this country I vi- 
sited Mount Idienne. The object of my journey was not 
only to examine the volcano at the summit of this movn- 
tain, one of the highest in Java, but also to explain the 
phenomena exhibited by a river a few leagues from Peana- 
roukan. The waters of this river are generally whitish ; 
in this state they have no bad taste, and are not hurtful to 
animals or to vegetation: but suddenly the white colour 
disappears; the colour becomes yellowish and dull, the 
taste very acid, and then these waters are fatal to all ani- 
mals who drink of them, and destroy the vegetation with 
which they come in contact. This phenomenon is inter- 
mittent, but it has neither stated period nor fixed duration. 
It is extremely prejudicial to the land on the banks of the 
river, as it cannot be cultivated with success. WhenT set 
out from Samarang to visit the eastern part of the island, 
M. Englehard, governor of Java, directed me to make in- 
quiries into these changes in the waters of the white river, 
with a view to discover some remedy. I wrote to him on 
the 30th of September 1805 the following letter, which 
contains my observations, and the description of the vol- 
cano changed into solfaterra, to which this phenomenon 
may be referred. 
« 30th September 1805. 
“* Within these few days I haye returned from my visit 
to 
