Messier, comet, 108; nebulous spot resembling our starry stratum, 151.

Metamorphic Rocks. See Rocks.

Meteorology, 311-339.

Meteors, see Aërolites; meteoric infusoria, 345, 346.

Methone, Hill of, 240.

Meyen on forming a thermal scale of cultivation, 324; on the reproductive organs of liverworts and algae, 341.

Meyer, Hermann von, on the organization of flying saurians, 274.

Milky Way, its figure, 89; views of Aristotle on, 103; vast telescopic breadth, 150; Milky Way of nebulous spots at right angles with that of the stars, 151.

Minerals, artificially formed, 268, 269.

Mines, greatest depth of, 157, 159; temperature, 158.