14 On the Height of Mountains, Headlands^ fyc. 



mometer at these stations gives 71° and 55° respectively. It is 

 required to find the perpendicular height of the mountain. 



Thermometer attached. Thermometer detached. 



Lower station, 68° Lower station, 71° 



Higher " 63 Higher " 55 



Difference, ~5 2)126 



■■ ■ 



Mean, 63 



Barometer at summit where attach'dj =26>13 . 14172 . 5 57 

 thermometer indicates least degree, ) 7 ■ 



From Table I, for 5 units, we have 2.28394 



■ ■ ii i i ■ ■ 



Log. corrected, 



Barometer at the base =29.862, log. 14751.189 



Take 14174.84094 



• 



14174.84094 



Log. 



576.34806 =2.7606848 



Then, from Table II, for 6 tens, 14808 



For 3 units, (making in all 63°,) 00740 

 Constant, 92102 



Log. 1.07650 =0.0320140 



Height in fathoms =620.4385, corresponding to log. 2.7926988 

 II. Wishing to know the perpendicular height of Chraughaim 

 mountain in the county of Wicklow, and having two barometers 

 and detached thermometers which for months before precisely 

 agreed with each other in different states of the air; leaving an 

 assistant on a level with the sea near Arklow, with directions to 

 make accurate observations every fifteen minutes from 3 to 4 

 o'clock, (our watches being previously regulated,) I proceeded to 

 the top of the mountain, and at the appointed hour commenced 

 observations. The mean result of the five were as follows : the 

 barometer stood at the summit 28.635, and at the base 30.609 

 inches ; attached thermometer 61° and 65.5°, and detached ther- 

 mometer 54.5° and 70°, respectively. It is required from these 

 data to find the height of the eminence. 



Thermometer attached. Thermometer detached. 



Lower station, 65.5° Lower station, 70° 



Upper " 61 Upper " 54.5 



Difference, 4.5 2)124.5 



Mean, 62.25 



