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APPENDIX. 
THE SUI4VEYS— THE llYEEOGEArniCAL, HYPSOMETEKAVL, AND 
STATISTICAL EESULTS— IIO^Y OBTAINED. 
TuorGii in a lew years puffing locomotims will be speeding tlirougli tlioin, tlio distriots 
we explored have till now been so dotaolied from oommuuieatiou ndtli the rest of tho 
world, and have, notwithstanding their natural wealth, par-tiiktm so little of the 
iutlueiice exercised by commerce over the com'se of universal history, that it is likely 
more than one of our readers lias had to refer to the maj), to call to mind the exact 
))ositiou of the different points in the groat Amazon Basin, or the Madeira, or the 
klamore Yalley. 
Nevertheless, with the opening of better means of intercourse, and with the 
e.xportation of their produce, these countries will acquire greater imjiortance in the 
future. They should evoke at least as much interest as does Central Africa, for 
instance; ivhich again and again attracts explorers and interests readers. Although, 
therefore, the results of oiu- voyage may be iucomjdeto in more respects than ono, and 
though our investigations frequently were hurried, yet they may not be altogether 
devoid of interest, on the score of this having been tho first e.xpodition to these regions 
undertaken of late years. I now proceed to give a short summary of the astronomical, 
h^fdrographical, hyjisometrical, and statistical results obtained. 
The astronomical observations were made in the following way : — 
Two ship’s chronometers (by Poole, of Loudon) having proved defective at Manaos, 
and former explorations haviug convinced us that these deHcute instruments suffer 
matei’ially, not only from their short transport on land, but also from the shocks and 
rockings of the rudder-boats, which soon disqualify them for determination of longi- 
tude, we resolved to base our calculations on observations of lunar distances. Though 
these (we always made two of them on imjiortaiit occasions) did not all prove to be of 
equal exactitude, we still had enough to ascertain beyond doubt the geographical 
situation of the chief line. 
The latitudes were determined by the altitude of the sun and of the stars, taken 
almost wherever we halted, the nightly observations being greatly favoured bj' the 
cloudless serenity of the sky during the diy season. The instruments used were an 
excellent circle de reflexion by Casella, and two sextants with artificial horizons ; the one 
used in first line being a mercury horizon. 
Between the princijial points of the expanse of water thus astronomically deter- 
mined, the detail of the river-course was obtained by means of a micrometer by Eochou 
and a prismatic compass. 
An exact triangulation, extending over the whole width of tho river, was necessarily 
out of the question, even if we coidd have found time for tho measuring, properly so 
culled, since the setting up of observatories and of trigonometrical signals in the dense 
forest, with the lunited staff at our disposal, would have required the preparation of 
yeiU’s. 
The levelling was generally done barometrically, with two aneroid barometers and 
a Ii vpsomcter (by tho temperature of boiling water), and on tho chief breaks tlie 
diflorence was, besides, directly measured by the luvelliug instrument. 
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