CHAPTER VII.
A SUGGESTION AS TO THE 'CANALS' OF MARS, -- Special features of the canals -- Mr.Pickering's suggested explanation -- The meteoritic hypotheses of origin of planets -- Probable mode of origin of Mars -- Structural straight lines on the earth -- Probable origin of the surface-features of Mars -- Symmetry of basaltic columns -- How this applies to Mars -- Suggested explanation of the oases -- Probable function of the great fissures -- Suggested origin of blue patches adjacent to snow-caps -- The double canals -- Concluding remarks on the canals..