746 Col. roy’s Experiments for 
fummits of Pichincha and Coracon, is that of 16793 
to- 1 . On the altitude of 1534 feet, intercepted between 
Carabourou and Quito, which fhort fection of the co- 
lumn is about half-way between the level of the fea, and 
the fummits of the Cordilleros, the mean temperature 
being 66°, the ratio is that of 15089 to 1: hence it 
feems probable, that quicklilver would have to the dif- 
ferent fedtions of the general column of air, compre- 
hended between the fea and the top of Coraqon, nearly 
the following ratios : 
T emp* 
At the level of the South Sea, 84^- 
Half-way from thence to Carabourou, 7 5^ 
At Carabourou, — — 66 ~ 
Half-way from thence to Coracon, 5 5 
At the fummit of Coraqon, — — 43J- 
13100 to 1 
14100 
15100 
16100 
17100 
Whereof the mean is, — 65 15 100 
Mr. bouguer tells us, that the barometer in the tor- 
rid zone varies not at the fea-lhore above two and a half, 
or at molt three lines throughout the whole year. At 
Popayan, its variation is only a line and a half; and at 
Quito a Angle line. Now let us fuppofe, that an altitude 
had been meafured with the barometer at the level of 
the 
