The following table of comparison between altitudes, determined by the level and by barometric observations, shows how much has been gained in accuracy, since the time of Humboldt, in the use of the barometer: _Table of data used in computing the various heights, with the results as compared with the heights obtained by the level._ ═════════════════════════════════════╤═════════════╤════════════ │MEAN READING │ MEAN STATIONS. │OF BAROMETER.│ TEMP. ─────────────────────────────────────┼─────────────┼──────────── │ INCHES. │ DEG. Sea coast │ 29.874 │ 80. First camp on Truando │ 29.817 │ 75.4 Tocame │ 29.805 │ 76.8 Foot of Saltos │ 29.759 │ 76.1 Observatory Hill │ 29.663 │ 76.6 Head Salto Grande │ 29.741 │ 75.9 Head of Saltos │ 29.737 │ 75.9 Junction of Rivers Nercua and Truando│ 29.674 │ 77. Tambo │ 29.607 │ 77. First Ridge west of Rio Nercua │ 28.815 │ 75.2 [9]Log Crossing on ┌ No. 1362│ 29.053 │ 75.2 Rio Hingador┤ │ │ └ No. 1363│ 28.912 │ 75.2 Camp on Hingador │ 29.074 │ 75.2 Dividing Ridge │ 28.913 │ 75.2 Rio Chupepe │ 29.631 │ 75.2 Rio Totumia, below Dos Bocas │ 29.837 │ 75.2 ─────────────────────────────────────┼───────────┬─┴────┬─────────── │ BAROMETRIC│HEIGHT│DIFFERENCE. │ HEIGHT. │ BY │ STATIONS. │ │LEVEL.│ ─────────────────────────────────────┼───────────┼──────┼─────────── │ FEET. │ FEET.│ FEET. Sea coast │ ... │ ... │ ... First camp on Truando │ 58.39│ 44.57│+ 13.82 Tocame │ 69.6 │ 57.39│ 12.21 Foot of Saltos │ 122.65│ 97.5 │ 25.15 Observatory Hill │ 207.45│204.95│ 2.5 Head Salto Grande │ 132.3 │138.79│- 6.49 Head of Saltos │ 138.1 │183.47│ 45.37 Junction of Rivers Nercua and Truando│ 192.5 │192.6 │+ 0.44 Tambo │ 260.92│264.4 │- 3.48 First Ridge west of Rio Nercua │ 1,046.45│ ... │ ... Log Crossing on ┌ No. 1362│ 809.42│791.23│+ 18.19