INDEX. 



639 



PRE 



Preparation of experiments, 312 

 Pressure, discovery of effects of 

 enormous, 559-560 



complex effects of, 33-34 



of steam at different tempera- 

 tures, discovery of, 479 



Prevost's discovery of the theory 



of exchanges, 591 

 Priestley's deficiency of education 



in chemistry, 295 



discoveries, 501, 502, 540, 542, 

 552 



Principle of coexistence of matter 

 and energy, 160 



of coincidence of change of 

 matter and its forces, 163 



of concurrence of causes, 165 



of conservation of matter and 

 energy, 160-161 



of correlation of forces, 163- 

 164 



of contradiction, 154 



of dissipation of energy, 162- 

 163 



of equivalency of forces, 164- 

 165 



of excluded middle, 154 



of identity, 154 



of isochronism, or rhythm, 520 



of persistency of phenomena, 

 161-162 



of sufficient reason, 154 



of transference of energy, 165 



of transformation of energy, 164 



of unequal action of causes, 

 165-166 



of universal causation, 160 



of universal existence of mat- 

 ter and energy, 162 



of universality of motion, 162 

 Principles of science, method of 



discovering, 585 

 a basis of the rules of 



morality, 521 



Probability in science, 150-152 

 Problem of the distribution of 



electricity on a spheroid, 606 

 Processes of mental analysis, &c., 



illustrated, 336-339 



which lead to discovery, 8-9 



RAD 



Proof, modes of, 352 



Proof -plane, invention of, 480 



Properties of bodies, usual in- 

 completeness of the, 393 



Prophecy, basis of, 344 



Proportionality of cause and effect, 

 405, 416 



Proposition, illustration of the 

 implicit contents of a, 333-336 



Propositions, 82, 87 

 - affirmative, inconsistent, con- 

 tradictory, equivalent, 82-89 



interfering, 351-352 



transformation of, 337-340 



quantification of ideas and, 52, 

 89, 341, 359, 451 



Prout's hypothesis of atomic 



weights, 124, 599 

 Psychology, researches in, 56-59 

 Pyro-electricity, discovery of, 491 



discoveries respecting, 534, 



535, 567-568 



Pythagoras's discovery of the pro- 

 perties of a right-angled tri- 

 angle, 610 



QUALIFICATIONS f ordiscovery, 



vj personal, 241 



Qualitative and quantitative ideas, 



51-52 

 knowledge, 202 



observation, importance of, 316 



truths, absolute nature of, 150 



truth, the foundation of science, 

 203 



Quantification of ideas and pro- 

 positions, 52, 89, 341, 359, 451 



Quantitative character of accuracy 

 in science, 149 



inference, 359 



nature of probability, 150 



results, future, 394-395 



T)ADIANT heat, Melloni's dis- 

 Xi coveries respecting, 228, 479, 



531, 548, 574 

 Radiometer, Crookes's invention of 



the, 479 



