Pulley, simple, 68; compound, 69; for-
mula for, 70; in the animal struc-
tures, 76

Pumps, 119: stomach, 120; limit to the
action of, 121

Quartz, its circularly-polarizing power,
374; deviations of the planes of polariza-
tion in a left-handed specimen, 375

Rainbow, theory of, 345

Rays of light defined, 296; parallel, con-
vergent and divergent, 297; index of
refraction for homogeneous, 324; ordi-
nary and extraordinary, 548
Reaction consequent on action, 36
Read, Mr., his lung-pump, 120
Reduvius serratus, electric properties of,
286

Reflection of motion, 36; of sound, 131;

of light, 297; internal, 309

Refraction of light, law of, 306; table of
absolute, 307; through planes, 310;
through prisms, 311; through spheres,
312; through lenses, 314; double, 348;
axis of, 349

velocity of propagation, 128; inter-
ference of, 129; reflection of, 131;
evolved by heated metals, 138; evolved
by rotating magnets, 240

Sound and light, analogy between, 293,
295, 335

Spark, electric, 183; observed in men,

288

Spectrum, 322; simplified by absorption,

326; mean rays of, 327; irrationality of,
329, dark bands in, 330; luminous powers
of, 331, calorific powers of, 332; chemi-
cal powers of, 333

Spectral colours, 398; produced by white
light, 399

Specula, 432

Spider, supposed electric phenomena of a,

286
Statics, 3

Steel-wire, tenacity of, 9
Stomach-pump, 120

Strehlke, his mode of detecting sonorous
vibrations, 138

Sugar, circularly-polarizing power of its
solutions, 377

Syphon, 121; Wirtemberg, 106; Tantalus,
108

of floating bodies, 20

Resistance of media, 24, 34, 47

Tabasheer, low refractive power of, 313
Tables of tenacity, 9; attraction, 14; co-
hesion, 16; capillarity, 17; exception to
isochronous vibrations in large arcs, 55;
lengths of pendula, 57; specific gravity,
97; conducting power of bodies for
sound, 129; of musical notes, 134; mag-
netic declination, 151; magnetic inclina-
tion, 152; electrics, 167; ratio between
incidents and reflected light, 298; mag-
nifying power of lenses, 320; undula-
tions of luminiferous ether, 325; dis-
persive power of bodies, 329; indices of
refraction for Fraunhofer's lines, 331;
double-refracting uni-axial crystals, 350;
of bi-axial crystals, 351; circularly-polar-
izing power of organic fluids, 377; di
chroism of bodies exposed to polarized
light, 380

Telescope, Newton's reflecting, 382; Gre-
gory's and Cassegrain's, 383; astronomic
refracting, 390; Galileo's refracting, ib.
Tenacity, 8

Tension, electric, 176

Thermo-electricity, 278; excited by one
metal, 279; by platina plunged in fused
salts, 280

Thermo-electric rotations, 279; spark and
shock, 280