93 
of Humboldt, although there is a difference of 200 feet in the 
height of the summit. 
«¢ Von Buch gives the following barometrical observations 
for the height of the summit :— 
Barom. At. Ther, Det. Ther. 
Orr the Peaks, “2921980 SS S6OP Feo? 
MdusantaOruz 9. ve BOLTS) hoor eae err eee 
From which, using the same method of calculation as before, I 
should deduce a height of 11,850 feet. 
‘Tf now we take all these observations as independent 
values, namely— 
Our mean . . . =12:008 by my calculations ; 
Mr. Evans’s, . . =12°105 
Humboldt’s height, = 12-204 
Von Buch’s, . . =11°850 
we shall find the mean of the whole to be 12,042 feet. 
‘¢On taking our mean by Professor Haughton’s calcula- 
tions at 11-940, we shall get the resulting mean = 12-029 feet. 
“ These means agree very closely with the heights deduced 
from our observations taken in ascending, when we divided the 
whole height of the mountain into three stages; and the dif- 
ference between Professor Haughton’s calculations and mine 
is less for those three observations than for the others. Whe- 
ther these considerations would be sufficient to give a preferen- 
tial value to those observations I will not pretend to decide. 
“ There is yet one other consideration :—Our two heights 
of the Peak above the Estancia de los Ingleses, whichever way 
they are calculated, agree within six feet. They may, there- 
fore, be looked on as very approximately true, and their mean 
is 2193 feet. The mean of the five values (including Hum- 
boldt’s) for the height of the Estancia de los Ingleses is 9847 
feet, which, added to 2193, gives a total of 12,040 feet for the 
height of the Peak. 
“The difference between this last value and the former one 
