Part 29

Laplace's theory of Saturn's rings, 285.

Latent heat, Black's theory of, 144; Cavendish's views on, 144.

Leonardo da Vinci's observation of capillary attraction, 228.

Leyden jar, discovery of, 4; energy of, resident in the glass, 79.

Leyden jars charged by cascade, 77.

Light, Franklin's view of nature of, 86; Maxwell's electro-magnetic theory of, 306; rotation of the plane of polarization of, 273.

Lightning, effects of, on Newbury steeple, 92.

Lightning-protectors, Maxwell's, 294.

Lightning-rod, illustrations of the, 83.

Lignum nephriticum, dichroism of, 30.

Lines of force mathematically investigated by Thomson and Maxwell, 300.

Lines of magnetic force fixed by Faraday, 269.

Luminiferous ether, the vehicle of electrical action, 227; illustration of the possible constitution of, 302.

Magdeburg hemispheres, experiments with, by Otto von Guericke, 17.

Magic squares, Franklin's proficiency in, 66.

"Magnetic spark" obtained by Faraday, 262.

Magnetization by induction, Boyle's experiments on, 34.

Magneto-electric machine, Faraday's, 262, 314.

Magneto-electric machines, Wilde's, 318; objects to be aimed at in the construction of, 315.

=Maxwell=, James Clerk, birth and parentage, 279; enters Edinburgh Academy, 280; letters to his father, 280; early papers before the Royal Society of Edinburgh, 281; visit to Mr. Nicol, 281; experiments with unannealed glass, 282; enters the University of Edinburgh, 282; enters Peterhouse, 282; migrates to Trinity, 282; degree in Cambridge, 283; elected Fellow of Trinity, 284; appointed Professor at Marischal College, 284; marriage, 287; essay on Saturn's rings, 285; dynamical top, 285; appointed professor at King's College, 287; lecture on colour at the Royal Institution, 287; work on the Electrical Standards Committee, 287; appointed Professor of Experimental Physics at Cambridge, 288; plans the Cavendish Laboratory, 288; lectures at Cambridge, 290; work on the Cavendish Manuscripts, 134, 293; delivers the Rede Lecture, 293; method of protecting buildings from lightning, 294; death, 294; colour-top, 295; experiments on colour-blindness, 296; colour-box, 297; awarded the Rumford Medal, 297; wheel of life, 297; real-image spectroscope, 298; discovery of stresses in Canada balsam, 298; of the insensibility of the fovea centralis to blue light, 298; statistical method, 299; explanation of the viscosity of gases, 299; investigations of Faraday's lines of force, 300; statement of the laws of electro-magnetic induction, 301; mechanical illustration of the ether, 302; explanation of induced currents, 304; of the mechanical action between currents and currents, and between magnets and currents, 304; of self-induction, 306; electro-magnetic theory of light, 306; contrivance for overcoming the principle of the dissipation of energy, 328.

Maxwell's experiment for showing electro-magnetic rotation, 258.

Mayer's determination of the mechanical equivalent of heat, 323.

Mechanical equivalent of heat, definition of, 193; Rumford's determination of, 192.

Mercury, melting point of, 145.

Mirabeau's declamation on Franklin, 123.

Mixed plates, colours of, 223.

Moral perfection, Franklin's endeavour to attain, 56.

Mother-of-pearl, Young's explanation of the colours of, 224.