100 Editorial Correspondence. y 
T have time to make only some general remarks, Humboldt’s sketch 
of Catopaxi is eeeeuy. overdrawn, And yet his mistake is | 
eo 
iving the north and south slopes. I have found that by means of 
evel, that the slope of the west side is 35°; while the west slope 
is 40°. Th 
volcano; I observed none around Tunguragua, Antisana alone 
lo 
I 
or the snow-limit in Ecuador is 15,790 ft.; yet Car- 
guirazo is as snow-clad as Cotopaxi. My theodolite was out of 
order, and I could not ascertain its true height. 
As to the porphyry of the Andes, it has been said that_ much of 
throug 
just south of Tungur al 
surface, very uniformly 30 feet 
them, as some think, it moved 
