Heightbyonebarometerascent
descent		2,567.7
2,625.4		mean2,596.5 feet.
Do.twodo.ascent
descent		2,619.3
2,596.7		—2,608.0
———
2,602.2
———

By angular measurement from Observation Cove, Port Famine, with theodolite, allowing 1⁄12 of the intercepted arc for terrestrial refraction, the height is 2,850 feet.

Another observation, with the sextant, made it 2,855 feet. The mean 2,852 I consider more correct, from the difficulty of obtaining a correct reading of the barometer on the summit.

[45] By Daniell's hygrometer, used in this sheltered spot, I found the temperature of the air to be 48°; dew point 41°: but upon exposing the instrument to the wind, the air was 39½°, and the dew point 36°: the difference in the former being 7°; and the latter 3½°; from which the following results are obtained:

air.dew pt.diff.exp.dryness.weight of a cubic
foot of air.
In the ravine484172927763.323
Exposed to wind39½363½2488982.871
Difference 8½ 53½ 441220.452

The above being the difference in the short space of three feet apart; the instrument, in the first case, being just under the lee of the rocky summit of the mountain, and in the last, above it, exposed to the wind.

[46] The air was so dry this afternoon that I failed to procure a deposit of dew upon Daniell's hygrometer, although the internal temperature was lowered from 61° to 37°. One of Jones's portable hygrometers was also tried, and the temperature was lowered to 31°½ without a deposit; so that, the difference being more than thirty degrees, the expansive force of the air must have been less than 212, the dryness, on the thermometric scale, less than 367, and the weight of vapour, in a cubic foot of air, less than 2,355 grains.

[47] Fires made to attract attention, and invite strangers to land.

[48] This fern we found at the island of Juan Fernandez also.

[49] After the lieutenant of the Adventure.