42 



BAROMETIIICAL OBSERVATIONS. 



Feb. 1827. 



the mercury 43°.* Unfortunately the day was very cloudy, 

 and many squalls of sleet and rain, which obscured the hills, 

 passed whilst I was taking bearings. To the N.E., towards 

 the supposed Sebastian Channel, the horizon was too hazy to 

 allow much view. A deep inlet was seen in that direction ; 

 but whether the land closed round, or whether a channel was 

 at the bottom, we could not distinguish. A considerable body 

 of water was observed to the southward of Cape St. Valentyn, 

 behind Lomas Bay, but its extent was screened from our view 

 by the intervention of the Lomas hills. It appeared to be a 

 channel, the opposite or eastern side of it being formed by the 

 high ranges previously seen from Point St. Mary. Cordovans 

 Ports San Antonio and Valdez were distinctly made out ; but, 

 to the southward, every thing was enveloped in mist. 



The bearings and observations, which occupied me nearly 

 two hours, being completed, we all adjourned to a sheltered 

 cleft in the rock close to our station, where we soon recovered 

 the use of our fingers.-f* 



* The result of the barometric observation for the height of Mount Tarn 

 is as follows : 



Height by one baroineter| descent 2 GSr,!}"^^^"^ 2,596-5 feet. 

 Do. two do. { rertlisl} - 



2,602-2 



By angular measurement from Observation Cove, Port Famine, with 

 theodolite, allowing -^l 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. 



t By Daniell's hygrometer, used in this sheltered spot, T found the 

 temperature of the air to be 48° ; dew point 41° : but upon exposing the 

 instrument to the wind, the air was 39|°, and the dew point 36° : the dif- 

 ference in the former being 7° ; and the latter 3^° ; from which the fol- 

 lowing results are obtained : 



air. dewpt. difF. exp. dryness. ""'tot'^ot^^!^"' 



In the ravine 48 41 7 292 776 3-323 

 Exposed to wind 39a 36 3| 248 898 2-871 



Dift'crencc "s] 5 3| 44 122 (M52 



The 



