Cumming's discoveries in thermo-
electricity, 545

Cuneus's discovery of the Leyden
jar, 234, 480

Curves, discovery by the method
of, 610–611

Cuthbertson's invention of 'guard-
ed gold points,' 481
Cuvier's discoveries respecting
animal structures, 580, 602-603
pleasure in making a discovery,
10

DALE'S, R. W., statements re-

specting the nature of voli-
tion, 101, 123, 127–133
D'Alibard's invention of the light-
ning rod, 480

Dalton's chemical theories, 502,
508, 580, 598-599

Daniell's invention of the con-
stant voltaic battery, 485
Darwin's biological theories, 181,
580, 603-604
Data, errors of, 115

necessity of correct, 86
Davy's (Sir H.) discoveries of the
alkali metals, 11, 181, 229, 483–
484, 522, 561

530, 536, 542, 551, 557,

561, 590-591

experiments on the electro-
lysis of water, 355-358, 432-433
excitement on discovering
potassium, 11

invention of the safety-
lamp, 530,531
Decomposability of electricity and
magnetism, hypothesis of, 520-
521
Decomposition of water by elec-
tricity, discovery of, 481, 535–
537, 546-547, 554
Deduction and Induction, 346

discovery by means of, 460-
461, 583, 584
Deductive and inductive action
of causes, 415

Definite proportions, doctrine of,
475

Definitions, 74

Definition, conditions of a good, 75
of science, 2

of scientific genius, 242-243,
252

of the human will, 127, 605
of the reasoning process, 332
of the power of imagination,
360

De la Rue's discoveries, 485, 561
De Luc's discoveries respecting
temperatures, 566

Density of the earth, error in re-
searches on the, 107

Dependence of discovery upon art,
187-188

Descartes' discoveries, 478, 589
Detection of occult causes, 125-
126

of minute objects, 323

of similarities and differences,
328-329

of individual substances, 393-
394

- of concurrent effects, 431
- of residual causes, 431-432
of inseparable coincidences,
446

of different crystalline sub-
stances by difference of angles,
598
Determination of causes, 418-435
of effects, 430
Determining causes, 411, 412
conditions of phenomena, 439
Diamagnetism, discovery of, 494,
561-562

discovery of polarity of, 511
Diamond, discovery of the com-
bustibility of, 541

Diathermancy of aqueous vapour,
discovery respecting the, 544
of gases and vapours, discovery
of the, 544, 548, 574

Melloni's discoveries in, 548,574
Differentiation of effects, 415
of phenomena, 165
Difficulties of scientific research,
11, 189, 209, 210, 211–212, 215–
216, 217–218, 372, 449

621

DIF

Difficulties in a research, rule for
overcoming them, 380
Difficulty of estimating import-
ance of scientific truths, 189
of explaining results, 449

of selecting a subject of re-
search, 372

Diffusion of liquids, Sir W. Thom-

son's experiments on the, 558
Diffraction of light, discovery of
the, 565

Discoverers, ability of women as
scientific, 282-284

books on the lives of, 262
contrasted with barren reason-
ers, 251-252

early circumstances of, 263–264
Discoveries, 'accidental,' 223
in the arts, 395

dependency of upon previous
ones, 170, 183, 223

examples of false, 135-137
rarity of great, 195
made by women, 282

- missed, instances of, 321, 452,
595

prediction of, 227

predicted, examples of, 204,
227, 229, 233, 524

relative importance of dif-
ferent, 189

unexpected, 223, 235

yet to be made, 7, 22, 26-28,
394, 469, 563

Discovery aided by analogy, 327

hypotheses, 363-367

and invention, difference be-
tween, 3

a condition of invention, 471
by analysis and synthesis, 217,
524-525

applying electricity to bo-

dies, 553-555

- peculiar minerals, 503-505-
or unexpected truths,
rare substances, 504-505
residual phenomena, 201-

residues of manufactures,

505-507

extending the researches of
others, 544

neglected parts of
science, 466-469

DIU

Discovery by the use of more
powerful instruments, 560-562
of causes by the method of
averages, 434-435

coincidences, 445–447
conditions of scientific, 463
which determine the nature

of a, 456

- contrasted with barren reason-
ing, 3

dependence of upon art, 187-

188

of exceptional instances, 386
'fundamental laws of,' 458
- future, vastness of, 7, 22, 26-28,
394, 469, 563

in the future, probable means
of effecting, 574

Glauber's rule of, 501

both inductive and deductive,
187

- inductive and deductive modes
of, 461, 524–525

invention a condition of, 471
instances of simultaneous, 578
limits of, 2, 15, 18, 21, 462–
464

man's power of, 169, 463
merit of, to whom due, 13
methods of, 9, 464

methods of, are usually con-
crete, 457

- modes of, difficulty of classi-
fying, 455

— personal qualifications for, 241
of residual phenomena, instance
of, 433

special modes of, 455-456
usually a concrete process, 576
instance of the value of logic
in, 355-358

Discussion, its influence on re-
search, 303

Dissipation of energy, theory of,
162-163

Distribution of electricity on a
spheroid, solution of the pro-
blem of, 606

Diurnal magnetic variation, dis-
covery of, 577

ELE

Electric action through glass, dis-
covery of, 532

- attraction, discoveries respect-
ing, 531

- balance, invention of, 486
charge of telegraph cables, dis-
covery of, 235, 496

of underground telegraph
wires, discovery of, 568-569
condensers, invention of, 481
conduction, discovery of, 553

resistance of metals, dis-
coveries in, 486

of liquefied carbonic acid,
543-544

of rarefied gases, 555
currents, discovery of induced,

493

in animal tissues, discovery

of, 574

distribution, laws of, 481
'exploring wires,' employment

of, 481

induction, discovery respecting
static, 567

instruments,

means of new, 479

discovery by

— ' kiss,' discovery of, 567
kite experiments, 534
invention of, 480

machine, discovery of advan-
tage of warming an, 531

improvement of the, 480
invention of, 480

pencil of rays from a point,
discovery of, 567

repulsion, discoveries respect-
ing, 533, 567

sparks, discoveries respecting,
533, 567

spectra in rarefied gases, dis-
coveries respecting, 536
telegraph, invention of, 537
Electricity and lightning, dis-
covery of the identity of, 534,
592

- and magnetism, hypothesis of
the decomposability of, 520-

521

animal, discovery of, 491–492

ELE

Electricity, discovery by examin-
ing the effects of, 555

of Franklin's theory of, 534
of magneto, 537, 548

of the mutual dependence
of the two kinds of, 567

of the earliest fact in vol-
taic, 535

of the great velocity of travel
of, 511, 533

of two kinds of, 533, 577,
591-592

evolved by pressure of Ice-
land spar, &c., discovery of, 535
frictional, discovery of, 491
has no weight, discovery that,
533

- hydro, discovery of, 493-494,
568

identity of from various sources,
509

produced by animal tissues,
discovery of, 568

pyro, discovery of, 491

polarity of, 534

thermo, discovery of, 537, 553
voltaic, discovery of, 492, 543
Electro-chemical action, inven-

tion of the theory of, 593

Faraday's discovery of

definite, 485

Electrotype, discovery of, 485
Elementary substances, false dis-
coveries of, 135-137

limits of number of, 15
prediction of new, 204, 524
Embryology, discoveries in, 579,
603

Empirical facts, 84

Encke's discoveries, 589-590, 609
Encouragement of research, in-
fluence of international, 287
- received by foreign discoverers,
265

Energy, its indestructibility by
man, 161
Enthusiasm in scientific research,
117, 241, 258
Equinoxes, discovery of the cause
of the precession of the, 608
the precession of the,

565
Equivalency of forces, 164–165, 585
Equivalent causes, 417