INDEX. 



783 



476 ; superposition of small 

 effects, 476. 



Probable error, 555. 



Probability, etymology of, 197 ; 

 theory of, 197 ; principles, 200 ; 

 calculations, 203; difficulties of 

 theory, 213; application of theory, 

 215 ; in induction, 219 ; in judi- 

 cial proceedings, 216 ; works on, 

 394 ; results of law, 656. 



Problems, to be worked by reader, 

 126 ; inverse problem of two 

 classes, 135 ; of three classes, 137. 



Proclus, commentaries of, 232. 



Proctor, R.A., star-drifts, 248. 



Projectiles, theory of, 466. 



Proper names, 27. 



Properties, generality of, 600 ; 

 uniform, 603 ; extreme instances, 

 607 ; correlation, 681. 



Property, logical, 699; peculiar,699. 



Proportion, simple, 501. 



Propositions, 36 ; negative, 43 ; 

 conversion of, 46 ; twofold mean- 

 ing, 47 ; disjunctive, 66 ; equi- 

 valence of, 115; identical, 119; 

 tautologous, 119. 



Protean verses, 175. 



Protoplasm, 524, 764. 



Prout's law, 263, 464. 



Provisional units, 323. 



Proximate statements, 144. 



Pyramidal numbers, 185. 



Pythagoras, on duality, 95; on the 

 number seven, 262, 624. 



QTTADKIC variation, 474. 



Qualitative, reasoning, 48 ; proposi- 

 tions, 119. 



Quantification of predicate, 41. 



Quantitative, reasoning, 48 ; pro- 

 positions, 119 ; questions, 278 ; 

 induction, 483. 



Quantities, continuous, 274 ; in- 

 commensurable, 275. 



Quaternions, 160, 634. 



Quetelet, 188 ; experiment on pro- 

 bability, 208 ; on mean and 

 average, 363 ; law of error, 378, 

 380 ; verification of law of error, 

 385. 



RADIAN, 306. 

 Eadiant matter, 642. 

 Radiation of heat, 430. 

 Radiometer, 435. 



Rainbow, theory of, 526, 533. 



Rainfall, variation of, 430. 



Ramean tree, 703, 704. 



Ramsden's balance, 304. 



Rankine, on specific heat of air, 

 557 ; reconcentration of energv, 

 751. 



Rational formulae, 489. 



Rayleigh, Lord, on graphical 

 method, 495. 



Reasoning, arithmetical, 167; nu- 

 merically definite, 168 ; geome- 

 trical, 458. 



Recorde, Robert, 15. 



Reduction, of syllogisms, 85 ; ad 

 absurdum, 415 ; of observations, 

 552, 572. 



Reflection, total, 650. 



Refraction, atmospheric, 340, 356, 

 500 ; law of, 501 ; conical, 540 ; 

 double, 585. 



Regnault, dilatation of mercury, 

 342 ; measurement of heat, 350 ; 

 exact experiment, 397 ; on Boyle's 

 law, 468, 471 ; latent heat of 

 steam, 487 ; graphical method, 

 494 ; specific heat of air, 557. 



Reid, on bifurcate classification, 697. 



Reign of law, 741, 759. 



Rejection of observations, 390. 



Relation, sign of, 17 ; logic of, 22 ; 

 logical, 35 ; axiom of, 164. 



Repetition, method of, 287, 288. 



Representative hypotheses, 524. 



Reproduction, modes of, 730. 



Reservation of judgment, 592. 



Residual effects, 558 ; phenomena, 

 560, 569. 



Resisting medium, 310, 523, 570. 



Resonance, 453. 



Reusch, on substitution, 21. 



Reversal, method of, 354. 



Revolution, quantity of, 306. 



Robertson, Prof. Croom, 27, 101. 



Robison, electric curves, 446. 



Rock-salt, 609. 



Rcemer, divided circle, 355; velocity 

 of light, 535. 



Roscoe, Prof., photometrical re- 

 searches, 273 ; solubility of salts, 

 280 ; constant flame, 441 ; ab- 

 sorption of gases, 499 ; vanadium, 

 528 ; atomic weight of vanadium, 

 392, 649. 



Rousseau on geometry, 233. 



Rules, of inference, 9, 17 ; indirect 



