178 
PICKERING. 
LUNAR AND HAWAIIAN PHYSICAL FEATURES COMPARED. 
ack. however, which comes to the surface 
various 
p' 
eastern Asia and 
western Africa, and stretching from the Dead Sea to Lake Nyassa, reaches the 
enormous length of 3500 miles. The longest known crack upon the Moon, that 
of Sirsalis, measures about 400 miles. 
It does not 
sarily follow, however, even if both the Martian and 1 
canals are due to vegetation, that the vegetation is watered 
th 
e same manner 
There is certainly an atmospheric circulation upon Mars, giving rise to clouds, that 
might aid materially any subterranean forces. Annals of Harvard College Observa- 
tory, LIII, 155. Whether these forces could be directed intelligently by assumed 
intelligent inhabitants of the planet we do not know. The only argument in favor 
of the existence of such inhabitants is the artificial appearance of the canals. 
four canals radiating from the little lake just above the 
of Fig 
The 
37 will 
appear to some minds quite as artificial in appearance as the four canals radiating 
from the elongated lake to the right of the centre of Figure 38. 
To the southeast and southwest of Kilauea lies a desert region crossed in places 
by steam cracks. One of the first questions that I asked my guide on reaching the 
Volcano House was if any of these cracks were still active. He assured me that 
eh 
the 
and 
the next day we visited some that were near Keanakakoi. 
The desert was found to be absolutely barren except for certain long, narrow strips 
of vegetation. 
These consisted chiefly of ferns, some bushes, and a few trees. It 
was found that they grew over the steam cracks, one of which is shown in Figure 39. 
This particular crack was a yard in width, over two yards in depth, and about thirty 
yards long. If the region could have been viewed from a slight elevation we should 
have found a system of canals crossing the desert, these canals being due to vege- 
tation, and differing in appearance from those found upon the Moon and Mars in no 
respect save size. 
