Mars is, apparently, in this distressing plight at the present moment, the signs being that its water supply is now exceedingly low. If, therefore, the planet possess inhabitants, there is but one course open to them in order to support life. Irrigation, and upon as vast a scale as possible, must be the all-engrossing Martian pursuit. So much is directly deducible from what we have learned at Flagstaff of the physical condition of the planet, quite apart from any question as to possible inhabitants. What the physical phenomena assert is this: if there be inhabitants, then irrigation must be the chief material concern of their lives.
At this point in our inquiry, when direct deduction from the general physical phenomena observable on the planet's surface shows that, were there inhabitants there, a system of irrigation would be an all-essential of their existence, the telescope presents us with perhaps the most startling discovery of modern times,—the so-called canals of Mars. These strange phenomena, together with the inferences to be drawn from them, we will now proceed to envisage.