Huacuava Mountains. 189 
En all this belt, the outline of some of the snowy peaks may frequently be 
observed, in clear weather, to the distance of 150 miles and upwards, with : 
sufficient distinctness, for an observer to fix his own position, by obvious 
methods; and thus, to be enabled to correct the geography of the older 
maps. [But as yet, we do not, by Captain Wesp’s survey, and that of 
Lieutenant Hererrr and myself, know the precise latitudes and longi- 
tudes of any peaks further to the S. I... than the latitude of 29. 49, 43. and 
longitude 81.2) nearly.. It would be very satisfactory, to determine the 
positions of those more eastern peaks,. visible from Patna, Monghir, 
Bhagalpivy and Rajmai, and this may be done with considerable’ pre- 
cision, by their Azémuiis, taken at the above places, with: their observed 
differences of latitude, and: differenees of longitude; taken with good. chro- 
nometers, carried down the river, i fast going light boats, whem the stream 
is most rapid: the boats would reach Monghir from Patna in: a day, and 
two good chronometers, cught to give the difference: of latitude, within: a 
quarter of a mile. The chronometrical measures, may also be compared 
and corrected by differences of:longitude taken by the firing-of gunpowder: 
the flash: of half a pound of gunpowder, fired at the hill house at Pir 
Pahdr near Monghir would be seen at Janghira rock, from which, a 
flash. would beseen at Patter Ghatta, below Bhagalpur, and.thence at 
Pir Pointf or Sicrt Gall, ox probably Rajmal. I am: by no means 
sure, that a flash from. the top of the Golah at Patna, might not be seen at 
Pir Pahér,. as-Baron. Vanzacu observed the effects of this sort of illumina- 
tion at places, so far distant. from. each other,. as: to be reciprocally con- 
| cealed from sight, by the curvature of the earth. By this method much 
may be done, and the longer the line the better. Of course it requires a: 
