OBJECTIVE MARS--"For nearly a century Mars has captivated the passionate interest of astronomers and the credulous imagination of the public--of which we had an example not long ago in the great 'Martian' scare instigated by a radio program. The facts, although not as exciting as the former speculations, are interesting enough. Easily the most conspicuous feature of the planet is the white caps that cover its polar regions. They display a fascinating rhythm of advance and retreat. At the end of winter in each hemisphere the polar cap covers some four million square miles. But even in midsummer a tiny dazzling spot remains near the pole. As to the fine structure of the 'canals' much uncertainty remains.--G¿rard de Vaucouleurs"