INDEX. 



793 



geometrical labours of, neglected in 

 Germany, 242 ; spectrum analysis, 

 278 ; researches of, ii. 75 ; electrical 

 researches, 189; on "singularities of 

 curves," 641 ; 670 ; new geometry, 

 671 ; 672 ; deficient in elegance, 677, 

 682 ; and Sophus Lie, 692 ; on higher 

 curvs, 700. 



Plutonists. See Neptunists. 



Poggendorf, 'Annalen,' i. 43, ii. 128, 

 133, 169, 487 ; refused Helmholtz's 

 'Ueber die Erhaltung der Kraft,' i. 

 205 ; Dictionary of, silent about Avo- 

 gadro, 428 ; refused Mohr's ' Ueber 

 die Natur der Warme,' ii. 107. 



Poincare, H., lectures on Maxwell's 

 theories, i. 251 ; on indefiniteness of 

 electro-magnetic theory, ii. 93 ; as- 

 tronomical mechanics, 101 ; Paris 

 Address, 1900, 188 ; discourse of, 

 199 ;- quoted, 635 ; quoted on Weier- 

 strass, 638 et seq.; 703, 705; on 

 "function," 689; 686, 690; on Rie- 

 mann and Weierstrass, 707, 708 ; 

 737. 



Poinsot, ii. 5 ; "geometrical mechanics," 

 101 ; on synthetic method, 670. 



Poisson, mechanics, - i. 44 ; 188, 345 ; 

 electricity, 347; "mecanique mole- 

 culaire," 359 ; 360 ; analysis of, 362 ; 

 370; Newton's law, 379; Fresnel's 

 calculations, ii. 25 ; retired from 

 commission on Fresnel's theory of 

 transverse vibrations, 26 ; theory of 

 elasticity, 31, 41 ; 32 ; properties of 

 ether, 33 ; referred to by Faraday, 69 ; 

 formula of, 72 ; theory of electric and 

 magnetic phenomena, 74 ; ' Memoire 

 sur la Theorie du Magnetisme' 

 quoted, 75 ; referred to, 76 ; 474 ; 

 science of chances, 568 ; on conver- 

 gency, 646 ; on Jacobi, 657 ; on 

 synthetic method, 670 ; 686. 



Polarisation of light, ii. 22. 



" Polarity," origin of the word, ii 22. 



Polymorphism, i. 446. 



' Polytechnic Journal,' Dingler's, ii. 

 134. 



' Polytechnique, 1'Ecole, Journal de," i. 

 41. 



Poncelet, J. V., mathematics, i. 45 ; 

 new science of geometry, 114 ; 187 ; 

 definitions of horse-power and work, 

 310; 360, ii. 5; 'Traite,' 76, 660; 

 ' Mecanique industrielle,' 100 ; practi- 

 cal school of, ib.; his influence on 

 practical mechanics, 101 ; thermotics, 

 118 ; first definite use of new con- 

 ceptions of power and work, 137 ; 



658 et seq.; his principle of continuity 



criticised, 660 ; quoted, 662 ; on 



"homology" and "reciprocity," 



663; 673; on ideal elements, 674; 



684, 685, 692. 

 Pond, not member of any university, i. 



238. 

 Poole, 'Index to Periodical Literature,' 



i. 40. 

 Pope, influence of, on German thought 



and literature, i. 212. 

 Popper, Jos., ii. 185. 

 Positivism, i. 307. 

 Potential, ii. 698. 

 Pouillet, Ohm's law, i. 365 ; influenced 



German thought, ii. 101 ; heat experi- 

 ments, 357. 



Poulton, Weismann's Essays, ii. 372. 

 Power Series, Infinite, ii. 707. 

 "Power," the term, introduced by 



Watt. ii. 99. 

 Poynting, Prof., contributions to 



Maxwell's electro-magnetic theory, ii. 



72 ; 193 ; and Thomson's ' Text-book 



of Physics,' Sound, 489. 

 Practical problems, solidarity of, i. 



32. 



Preston, T., ii. 361. 

 Prevost, theory of exchanges, ii. 46. 

 Preyer, Prof: W., theory of "Pans- 



permia," ii. 369 ; school of Darwinism 



in Germany, 436 ; 470. 

 Priestley, chemical discoveries of, i. 115 ; 



155 ; scientific discoveries of, 229 ; 



not member of any university, 238, 



272 ; ' History of Optics,' 358, ii. 9 ; 



follower of Boscovich, i. 359 ; and 



Lavoisier, 386, 387 ; effect of plants 



on air, ii.. 391; 

 Prime numbers, ii. 722 et seq. 

 Pringle-Pattison. See Seth. 

 Pringsheim, A., on theory of functions, 



ii. 693 ; 734, 739. 



Pringsheim, N., observations, ii. 447. 

 Pritchard, "immersion" system in 



microscope, ii. 228. 

 Probability, theory of, i. 118, ii. 566. 

 Prochaska, "reflex action," i. 292; ii. 



519. 

 Proclus on Greek mathematicians, ii. 



634. 

 Progress, intellectual, two factors of, i. 



27. 



Projection, method of, ii. 663. 

 Projective and metrical geometry, ii. 



668 ; properties, 717. 

 Proportions, fixed, rule of, i. 392 ; mul- 

 tiple, rule of, 398. 

 ' Protogaea ' of Leibniz, ii. 277, 280. 



