INDEX. 



645 



TER 



Terrestrial magnetic poles, in- 

 fluence of the moon on the, 578 



Gauss's discovery of his 

 theory of, 594-595 



phenomena, the sun as a source 

 of, 407 



physics, discoveries in, how 

 made, 571 



Testing a supposed cause, 426-427 

 Tests, discovery of chemical, 555, 



571 

 Thallium, discovery of, 506-507, 



518 

 Theories, errors arising from false, 



124 



of electrolysis, 593 



Theory of an universal ether, 589 



of chemistry, modern, 595-596 

 origin of Dalton's, 598- 



599 



of decrements, in relation to 

 crystalline forms, 601 



of descent, origin of the, 580 



of electricity, Franklin's, 534 



of electro-chemical action, 593 



of electro-magnetic action, 

 Ampere's, 593-594 



exchanges, 591 



the gradual evolution of 



animals from a single ancestor, 



602 



phlogiston, 595 



testing of the, 512-513 



terrestrial magnetism, 

 Gauss's, 594-595 



Thermic repulsion, discovery of, 



494 

 Thermo-electricity, decomposition 



of water by means of, 537 



discovery of, 537, 553, 594 



-electric properties of meso- 

 type, boracite, prehnite, &c., 

 discovery of, 535 



Thermometer, invention and im- 

 provement of the, 479 



Thickness of thin lamina, dis- 

 covery of the, 589 



Thilorier's discovery of the solidi- 

 fication of carbonic anhydride, 

 531-559 



TRU 



Thomson's, Archbishop, criteria 

 of truth, 153-155 



J., ' Integrating Machine,' 607 



Sir W., experiments on the dif- 

 fusion of liquids, 658 



' Harmonic analyser,' 607 



invention of quadrant 



and absolute electrometers, 481 



prediction of new phe- 

 nomena, 232 



'Thought, fundamental laws of,' 

 343 



investigation of, 57 



the velocity of, 55 



Time, as a condition of success in 

 research, 273 



discovery by examining the in- 

 fluence of, 557 



Topaz, discovery of the electric 

 properties of heated, 535 



Torricellrs invention of the baro- 

 meter, 474 



Torsion balance, invention of the, 

 480 



Tourmaline, discovery of the elec- 

 tric polarity of a heated, 534 



Transfer of elements by electro- 

 lysis, discovery of, 554-555 



Transference of energy, the prin- 

 ciple of, 165 



Transformation of energy, the 

 principle of, 164 



of ideas, illustrated, 337-340 

 Transparency of rock salt to heat, 



discovery of the, 531 



Travel, discoveries made by means 

 of, 564 



Triangle, discovery of the pro- 

 perty of a right-angled, 610 



TrommsdorfFs experiments of vol- 

 taic ignition of leaf metal, 547, 

 560-561 



Trustworthiness in science, 145, 

 148-149 



Truth, criteria of scientific, 18, 



141, 153, 155 



- by what mental faculty de- 

 tected, 156-157 



extraction of by the process of 

 reasoning, 333-342 



