Lowell, Percival, observations on Mars, 167 _et seq._; map of
Mars, reliability of, 198.
Lucretius, birth-time of the world, 1.
Lugeon, formation of the Préalpes, 171; sections in the Alps,
154.
Lyell, uniformity in geological history, 15.
M.
Magee, relative areas of deposition and denudation, 16.
Mars, climate of, 170; position in solar system, 174, 175;
dimensions of satellites of, 177; snow on, 169; water on, 169;
clouds on, 169; atmosphere of, 170; melting of snow on, 170;
dimensions of canals, 171; signal on, 172; times of opposition,
164; orbit of, 165; distance from the Earth, 165; eccentricity of
his orbit, 165; observations of, by Schiaparelli, 165, 166;
Lowell's observations on, 167 _et seq._
Maxwell, Clerk, changes made under constraints, 65; on
conservation of energy, 61.
M'Connel, J. C., viscosity and rigidity of ice, 284.
Memory, physiological, 111, 112.