Lane's unit jar, 115.

Language, knowledge of the nature of, demanded by a liberal education, 356; relationship between, and thought, 358; communication by 237; economy of, 191 et seq.; human its character, 238; of animals, 238; instruction in, 338 et seq.; its methods, 192.

Laplace, on the atoms of the brain, 188; on the scientific achievements of the eighteenth century, 188; his hypothesis of the origin of the planetary system, 5.

Latent heat, 167, 178, 244.

Latin city of Maupertuis, 339.

Latin, instruction in, 311 et seq.; introduced with the Christian Church, 340; the language of scholars, the medium of international intercourse, its power, utility, and final abandonment, 341-347; the wealth of its literature, 348; the excessive study of, 346, 349, 354, 355; its power to sharpen the judgment, 357-358.

Lavish extravagance of science, 189.

Law, a, defined, 256; a natural, not contained in the conformity of the energies, 175.

Law-maker, motives of not always discernible, 9.

Layard, 79.

Learning, its nature, 366 et seq.

Least superficial area, principle of, accounted for by the mutual attractions of liquid particles, 13-14; ill.u.s.trated by a pulley arrangement, 12-13; also 9 et seq.

Leibnitz, on harmony, 33; on international intercourse, 342, footnote.

Lessing, quotation from, 47.

Letters of the alphabet, their symmetry, 94, 97.

Level heights of work, 172-174.

Lever, a, in action, 222.

Leverrier, prediction of the planet Neptune, 29.

Leyden jar, 114.

Liberal education, a, 341 et seq., 359, 371.

Libraries, thoughts stored up in, 237.

Lichtenberg, on instruction, 276, 370.

Licius, a Chinese philosopher, 213.

Liebig, 163, 278.

Life and death, 186.

Light, history of as elucidating how theories obstruct research, 242; Huygens's and Newton's views of, 227-228; its different conceptions, 226; rectilinear propagation of, 194; rAle of, in vision, 81; spatial and temporal periodicity of, explains optical phenomena, 194; numerical velocity of, 58; where does it go to? 199; generally, 48 et seq.

Like effects in like circ.u.mstances, 199.

Likeness, 388, 391.

Lilliput, 84.

Lines, straight, their symmetry, 98; curved, their asymmetry, 98; of force, 249.

Links of thought, intermediate, 198.

Liquefaction, latent heat of, 178.

Liquid, efflux, law of, 150; equilibrium, figures of, 4 et seq.; the latter produced in open air, 7-8; their beauty and multiplicity of form, 7, 8; made permanent by melted colophonium, 7.

Liquids, forms of, 1-16; difference between, and solids, 2; their mobility and adaptiveness of form, 3; the courtiers par excellence of the natural bodies, 3; possess under certain circ.u.mstances forms of their own, 3.

Living force, 137, 184; law of the conservation of, 149.

Lloyd, observation of the conical refraction of light, 29.

Lobster, of Lake Mohrin, the, 61.

Localisation, cerebral, 210.

Locke, on language and thought, 358.

Locomotive, steam in the boiler of, 219.

Loeb, J., 289, 291, 302.

Logarithms, 195, 219; in music, 103-104.

Logical root, of the principle of energy, 181; of the principle of excluded perpetual motion, 182.

Lombroso, 280.

Lucian, 347.

Macula acustica, 272.

Magic lantern, 96.

Magic powers of nature, 189.

Magical power of science, belief in the, 189.

Magnet, a, 220; will compared to the pressure of a, 14; coercive force of a, 216.

Magnetic needle, near a current, 207.

Magnetised bar of steel, 242-243.

Major and minor keys in music, 100 et seq.

Malus, 242.

Man, a fragment of nature's life, 49; his life embraces others, 234.

Mann, 364.

Ma.n.u.script in a mirror, 93.

Maple syrup, statues of, on Moon, 4.

Marx, 35.

Material, the relations of work with heat and the consumption of, 245 et seq.

Mathematical methods, their character, 197-198.

Mathematics, economy of, 195; on instruction in, 338-374; C. G. J. Jacobi on, 280.

Matter, constancy of, 203; its nature, 203; the notion of, 213.

Maupertuis, his Latin city, 338.

Maximal and minimal problems, their rAle in physics, 14, footnote.

Mayer, J. R., his conception of energy, 245, 246; his methods of thought, 247; on the conservation of energy, 163, 164, 165, 167, 183, 184; his metaphysical utterances, 183, 246; also 138, 184, 191, 217, 271, 274.

Measurement, definition of, 206.

Measures, international, 108.

MAcanique cAleste, 90, 188; sociale, and morale, the, 90.

Mechanical, conception of the world, 105, 155 et seq., 188, 207; energy, W. Thomson on waste of, 175; a.n.a.logies between ---- and thermal energy, 17 et seq.; equivalent of heat, electricity, etc., 164, 167 et seq.; mythology, 207; phenomena, physical events as, 182; philosophy, 188; physics, 155-160, 212; subst.i.tution-value of heat, 178, footnote.

Mechanics, Kirchhoff's definition of, 236.

Medicine, students of, 326.

Melody, 101.

Melsens, 310, 327.

Memory, a treasure-house for comparison, 230; common elements impressed upon the, 180; its importance, 238; science disburdens the, 193.

Mendelejeff, his periodical series, 256.

Mental, adaptation, 214-235; completion of phenomena, 220; imagery, 253; imitation, our schematic, 199; processes, economical, 195; reproduction, 198; visualisation, 250.

Mephistopheles, 88.

Mercantile principle, a miserly, at the basis of science, 15.

Mersenne, 377.

Mesmerism, the mental state of ordinary minds, 228.

Metaphysical establishment of doctrine of energy, 183.

Metaphysical spooks, 222.

Metrical, concepts of electricity, 107 et seq.; notions, energy and entropy are, 178; units, the building-stones of the physicist, 253.

Metronomes, 41.

Meyer, Lothar, his periodical series, 256.

Middle Ages, 243, 349.

Midsummer Night's Dream, 309.

Mill, John Stuart, 230.

Millers, school for, 326.

Mill-wheel, doing work, 161.

Mimicking facts in thought, 189, 193.

Minor and major keys in music, 100 et seq.

Mirror, symmetrical reversion of objects in, 92 et seq.

Miserly mercantile principle at the basis of science, 15.

Moat, child looking into, 208.

Modern scientists, adherents of the mechanical philosophy, 188.

Molecular theories, 104.

Molecules, 203, 207.

MoliAre, 234.