478 



INDEX. 



Prime numbers, i. 141, 265. 

 Principia, ii. 227. 



Principle, of probability, i. 228; of 

 inverse method, 2 79 ; of forced vibra 

 tions, ii. 65, 332; of coexistence of 

 small vibrations, 97; of super-position 

 of small effects, 98. 



Probability, meaning of, i. 224; princi 

 ples of, 228; rules of, 231; com 

 parison with experience, 238 ; diffi 

 culties of theory, 243 ; inductive 

 application of, 276; inverse method 

 of, 279; ii. 244; application to 

 astronomy, i. 285 ; inverse problem, 

 289; general solution, 295; rules of 

 inverse method, 297 ; works on, 459. 



Probable error, i. 451 ; ii. 194. 



Proclus, commentaries of, i. 267. 



Proctor, R. A., on star drifts, i. 287. 



Projectiles, theory of, ii. 85. 



Properties, generality of, ii. 249 ; uni 

 form, 254 ; variable, 258 ; extreme, 

 259 ; correlation of, 353. 



Property, logical, ii. 377; peculiar, 

 377-. . 



Propositions, i. 43 ; negative, 52 ; con 

 version of, 55; twofold interpretation 

 of, 57; disjunctive, 89; equivalency 

 of, 132. 



Protean verses, i. 197. 



Protoplasm, ii. 155. 



Prout, law of, i. 304 ; ii. 82. 



Pythagoras, on duality, i. no; on 

 number seven, ii. 279. 



Q. 



Quadric variations, ii. 95. 



Quantification of predicate, i. 49 ; ii. 

 387. 



Quantity, continuous, i. 318; ii. loS ; 

 of revolution, i. 358. 



Quartz crystals, i. 367 ; ii. 261, 287. 



Quaternions, i. 180; ii. 457. 



Quetelet, on average, i. 214; experi 

 ments on probability, 237; use of 

 mean, 421 ; law of error, 441 ; ii. 

 321; errors of observation, i. 446; 

 letters on probability, 459. 



R. 



Eainbow, ii. 159, 167, 247. 



Rain-guage, ii. 40. 



Ramean tree, ii. 385. 



Rankine, ii. 197 ; reconcentration of 



energy, 447. 



Rational formulae, ii. 113. 

 Reduction, indirect, i. 100; ad absur- 



dum, ii. 20. 



Reflection, total, ii. 314. 

 Refraction, atmospheric, i. 413 ; ii. 



126; double, ii. 34; law of, 128. 



Regnault, dilatation of mercury, i. 

 396 ; measurement of heat, 405 ; 

 dilatation of gases, 462 ; ii. 87 ; 

 latent heat of steam, in ; graphical 

 method, 118; specific heat of air, 197. 

 Regular system of crystals, ii. 360. 

 Reign of law, ii. 428. 

 Rejection of observations, i. 456. 

 Relation, sign of, i. 20; logic of, 27. 

 Repetition, method of, i. 335, 336, 353. 

 Representative hypotheses, ii. 156. 

 Residual phenomena, ii. 199, 201. 

 Resisting medium, i. 363; ii. 155, 213. 

 Retrograde motion, ii. 327. 

 Reversal, method of, i. 410. 

 Revolution, quantity of, i. 358. 

 Robison, electric curves, ii. 58. 

 Rock-salt, ii. 40, 261. 

 Roemer, divided circle, i. 411 ; velocity 



of light, ii. 169. 



Roscoe, chemical action of light, i. 

 316; experiments on solubility, 325; 

 standard unit of light, 378 ; ii. 52; 

 researches on vanadium, i. 457; ii. 

 312 ; absorption of gases, 125. 

 Rotation of plane of polarized light, ii. 



3i8. 



Rousseau on geometry, i. 268. 

 Rules, for calculation of combinations, 

 i. 204; of probabilities, 231 ; of in 

 verse method, 297 ; for elimination 

 of error, 409. 



Rumford, i. 397, 405 ; ii. 86. 

 Ruminant animals, ii. 356, 391. 



Sandeman, perigon, i. 358; approximate 



arithmetic, ii. 104. 

 Saturn, satellite of, i. 341 ; rings of, 



ii. 319. 



Secular variations, ii. 61. 

 Selenium, ii. 330, 341. 

 Seven, fallacies concerning number, i. 



303; ii. 279. 

 Sidereal day, i. 337, 362. 

 Simple identity, i. 44 ; inference with, 

 6i; contrapositive of, 101; induction 

 of, 146. 

 Simplicity, law of, i. 39, 85, 87, 181 ; 



axiom of, ii. 280. 

 Slate, logical, i. no. 

 Smeaton, experiments on friction, i. 



402 ; on windmills, ii. 4, 52. 

 Smee, Alfred, logical machines, i. 124. 

 Smell, sense of, ii. 47, 424. 

 Socrates, error of, ii. 263 ; on &quot;kind, 406. 

 Sodium-light, ii. 39, 47, 261. 

 Solar day, i. 337, 355 ; system, ii. 356. 

 Solids, ii. 252. 

 Solubility, i. 324. 



Some, indeterminate adjective, i. 49, 

 67, 71, 100. 



