364 LOWELL—THE CARTOUCHES OF MARS. [Dee. 4, 
Two things are necessary to the begetting of vegetal life, the raw 
material and the reacting agent. Oxygen, nitrogen, water and a — 
few salts make up the first, the sun does the second. Unless both | 
be present the quickening into life never comes. Now the one 
may be there and the other not, or the other there and the one not. 
On earth the material including water is, except in certain destitute 
spots, always present; the sun it is that periodically withdraws. 
Observant upon the coming of the sun is then the annual quicken- 
ing of vegetal life. On Mars, on the other hand, it is the water that 
is lacking. This we know from many other phenomena the disk 
presents. There is no surface water there save for what comes from 
the periodic thawing of the polar caps. Vegetation cannot start 
in any quantity until this water reaches it. Vegetal change, there- 
fore, on Mars should start from the pole and travel equatorward. 
On the earth it should do the precise opposite. _Nowsuch is exactly 
what the curves of visibility of the canals exhibit. Timed prima- 
rily not to the coming of the sun but to the coming of the water, 
vegetal dife there follows not the former up the latitudes but the 
latter down the disk. We may conclude then that the canals are 
strips of vegetation fed by water released from the polar cap. 
The two curves of phenological quickening, the mundane and 
the Martian, are shown in Plates XVI and XVII. The stars mark 
the dead-points at successive latitudes. 
We now come to a deduction from the evidence before us even 
more startlingly pregnant of information. Glancing at Plate XV 
of the mean canals, we see that the quickening proceeds rapidly 
and very nearly if not quite uniformly down the disk. It takes a 
the darkening only fifty days to descend from the seventy-first 
parallel to the equator, a journey of some 2600 miles. This means 
a speed of fifty-three miles a day, or two and two-tenths miles an 
hour. And it does this in the face of gravity. For the spheroidal _ 
flattening of Mars, ;3, of the polar diameter, shows that the figure 
of the planet is in fluid equilibrium under the axial rotation. A 
particle of water, therefore, would know no inclination to move 
from where it initially was. Of its own accord it would not flow 
toward the equator. And as it does flow toward the equator, and 
with a remarkably steady progression too, the inference seems — 
inevitable that it must be carried thither by artificial means. We 
are thus led to an artificial origin and maintenance of the markings 
called canals, and one which in essence justifies that appellative. 
Nor do I see any escape from the deduction. 
