Various photographs of Jupiter have been obtained; those which have been taken at the Lick Observatory being specially interesting and instructive. Pictures of the planet obtained with the camera in remarkable circumstances are represented in Figs. 57-60, which were taken by Professor Wm. H. Pickering at Arequipa, Peru, on the 12th of August, 1892.[21] The small object with the belts is the planet Jupiter. The large advancing disc (of which only a small part can be shown) is the moon. The phenomenon illustrated is called the "occultation" of the planet. The planet is half-way behind the moon in Fig. 59, while in Fig. 60 half of the planet is still hidden by the dark limb of the moon. It is well known that the tempests by which the atmosphere surrounding the earth is convulsed are to be ultimately attributed to the heat of the sun. It is the rays from the great luminary which, striking on the vast continents, warm the air in contact therewith. This heated air becomes lighter, and rises, while air to supply its place must flow in along the surface. The currents so produced form a breeze or a wind; while, under exceptional circumstances, we have the phenomena of cyclones and hurricanes, all originated by the sun's heat. Need we add that the rains, which so often accompany the storms, have also arisen from the solar beams, which have distilled from the wide expanse of ocean the moisture by which the earth is refreshed? The storms on Jupiter seem to be vastly greater than those on the earth. Yet the intensity of the sun's heat on Jupiter is only a mere fraction--less, indeed, than the twenty-fifth part--of that received by the earth. It is incredible that the motive power of the appalling tempests on the great planet can be entirely, or even largely, due to the feeble influence of solar heat. We are, therefore, led to seek for some other source of such disturbances. What that source is to be will appear obvious when we admit that Jupiter still retains a large proportion of primitive internal heat. Just as the sun itself is distracted by violent tempests as an accompaniment of its intense internal fervour, so, in a lesser degree, do we observe the same phenomena in Jupiter. It may also be noticed that the spots on the sun usually lie in more or less regular zones, parallel to its equator, the arrangement being in this respect not dissimilar to that of the belts on Jupiter.