Jupiter is the largest planet of the system, and when in and near opposition shines with a brilliancy inferior only to Venus. A friend of the writer has informed him that on October 16, 1857, the planet's lustre was so considerable as to throw a sensible shadow. When telescopically examined, the surface of Jupiter is found to be marked with a series of dusky streaks, commonly known as the “ belts.” These belts vary greatly in form, size, and number from time to time. Occasionally only two or three broad ones are seen, at other times as many as eight, ten, or even a dozen narrow ones. Their physical nature is not well understood, but they are usually considered to be masses of cloud, acted upon in a manner in some way analogous to our terrestrial trade-winds, If this is the true hypothesis, as probably it is, then the planet has wind, rain, water and clouds, and is consequently fitted for the existence of animal and vegetable life. The existence of the belts was first detected by Zuppi, at Naples, in May 1730, though a claim has been put in on behalf of Torricelli.