Much attention has been directed within the last few years to the observations of Lowell, made with a fine 24-inch refractor at the same observatory, which is situated at an elevation of over 7,000 feet. His conclusion as to the reality of the canals is most positive; but in addition to his confirmation of their existence, he has put forward other views with regard to Mars which as yet have found comparatively few supporters. He has pointed out that in almost all instances the canals radiate from certain round spots which dot the surface of the planet. These spots, which have been seen to a certain extent by other observers, he calls 'oases,' using the term in its ordinary terrestrial significance. His conclusions are, briefly, as follows: That Mars has an atmosphere; that the dark regions are not seas, but marshy tracts of vegetation; that the polar caps are snow and ice, and the reddish portions of the surface desert land. The canals he holds to be waterways, lined on either bank by vegetation, so that we see, not the actual canal, but the green strip of fertilized land through which it passes, while the round dark spots or 'oases' he believes to be the actual population centres of the planet, where the inhabitants cluster to profit by the fertility created by the canals. In support of this view he adduces the observed fact that the canals and oases begin to darken as the polar caps melt, and reasons that this implies that the water set free by the melting of the polar snows is conveyed by artificial means to make the wilderness rejoice. Lowell's theories may seem, very likely are, somewhat fanciful. It must be remembered, however, that the ground facts of his argument are at least unquestionable, whatever may be thought of his inferences. The melting of the polar caps is matter of direct observation; nor can it be questioned that it is followed by the darkening of the canal system. It is probably wiser not to dogmatize upon the reasons and purposes of these phenomena, for the very sufficient reason that we have no means of arriving at any certitude. Terrestrial analogies cannot safely be used in connection with a globe whose conditions are so different from those of our own earth. The matter is well summed up by Miss Agnes Clerke: 'Evidently the relations of solid and liquid in that remote orb are abnormal; they cannot be completely explained by terrestrial analogies. Yet a series of well-authenticated phenomena are intelligible only on the supposition that Mars is, in some real sense a terraqueous globe. Where snows melt there must be water; and the origin of the Rhone from a great glacier is scarcely more evident to our senses than the dissolution of the Martian ice-caps into pools and streams.' [Illustration: PLATE XXI. Chart of Mars. 'Memoirs of the British Astronomical Association,' Vol. XI., Part III., Plate VI.]