ple. What liquids have never been frozen? Give some examples of the immense power exerted when a liquid passes from a liquid to a solid state. Explain regelation. 310. What are crystals? What is crystallization? Examples. Give and explain the methods of crystallization. 311. What is a freezing mixture? Example. Explain its action. 312. Define vaporization, evaporation, boiling, and sublimation. What two classes of liquids have we? Define each, and give examples. 313. Illustrate the tension of vapors by experiment. Give some examples of the power of steam. 314. Why do vapors escape from the surface of liquids' When the pressure is removed, what happens? Illustrate the principle by the experiment. What does the experiment show? 315. When does vapor cease to form? 316. Give four causes that accelerate evaporation. Give illustrations and applications of these causes. 317. What is ebullition, or boiling? Explain the phenomena of boiling Give the two laws of ebullition. Illustrate. 318. What are the principal causes that modify the boiling-point? Illustrate by examples. 319. What principle does Papin's digester illustrate? Explain its construction and use. What causes explosion in steam-boilers? 320. Who have measured the elastic force of vapors? What is proved? 321. What is the latent heat of vaporization? Explain latent heat as a type of energy. 322. Explain latent heat of steam by example. Illustrate by experiment. 323. Give examples of cold produced by heat becoming latent. 324. Explain the spheroidal state of a liquid. Illustrate by example. 325. Why does evaporation produce cold in surrounding objects? How can we produce cold with sulphurous acid and the spheroidal state of a liquid? 326. What is condensation of a vapor? Causes? Explain and illustrate each by examples. 327. Explain how heat is developed by condensation. 328. Explain heating buildings by steam. 329. Define distillation. Explain. 330. Describe the alembic, or still. Explain the method of using it. How is alcohol distilled water? 331. How may gases be liquefied? Explain the apparatus and process for liquefying carbonic acid gas. What is the appearance of the frozen acid? How is extreme cold obtained with the solid acid? how with bisulphide of carbon and nitrogen protoxide? 332. Explain by examples specific heat of solids and liquids. What is a unit of heat? 333. Define specific heat. What methods are employed for finding the specific heat of bodies? 334. Explain the method of mixture with example. 335. Explain the method by melting ice. Explain the construction and method of using the calorimeter. Give results. Show by experiment with the disk of wax that the specific heats of different substances differ very widely. 336. Explain specific heat of gases. How does the specific heat of a body in the liquid form compare with that of the same body in a solid or gaseous form? What substance has the greatest specific heat? What next? 337. What are the principal sources of heat? Explain and illustrate each with experiments or examples. 338. What are the principal sources of cold? Explain and illustrate each. 339. Define thermo-dynamics. 340. Explain and illustrate conservation of energy. Give the first law of thermo-dynamics. 341. Describe the apparatus of Joule. How used? What is meant by the mechanical equivalent of heat? 342. Explain and illustrate transformation of energy. 343. Explain and illustrate dissipation of energy. 344. What is a steam-engine? Of what two parts does it consist? 345. Illustrate by experiment the power of steam. Explain and illustrate the tension of steam. 346. Name the varieties of steam-engine. Explain each. What advantages does each have? What is meant by horse-power? 347. Of what is the steam-boiler generally made? Use? Describe some of the forms of boilers. What object is kept in view in the construction of the boiler? Describe in detail the boiler and its appendages. 348. Name the different kinds of manometers. Explain the construction and method of using each. What advantages has the metallic over the mercurial? 349. Describe the structure of the condensingengine in detail. Explain its working. 350. Describe the structure and working of the governor. What is its use? 351. Illustrate the action of the eccentric. 352. Describe in detail the structure of the locomotive. 353. Define hygrometry. When is a given space saturated? Example. Effect of temperature on saturation. Causes that vary the amount of watery vapor in the atmos phere. What is the real object of hygrometry? When does the air contain the greatest absolute amount of vapor? 354. What is the hygroscope? Give examples of some hy. groscopic substances. 355. What is the hygrometer? Name three kinds. Explain the hair hygrometer. 356. Describe the construction of Daniell's dew-point hygrometer. Explain its action. 357. Describe the construction and working of the wet and dry bulb hygrometer. 358. Define mists, fogs, and clouds. What are the causes of clouds? Give the theories to explain why clouds remain suspended in the air. Where are fogs and mists formed to the greatest extent? 359. Name and explain the different varieties of clouds. 360. What is rain? How formed? Upon what does the quantity of rain depend? 361. What is dew? Give Wells's theory. What is the dew-point? Give common examples of the deposition of dew. What is frost? What has the moon to do with freezing? 362. How is snow formed? Of what are snow-flakes composed? Where does snow fall in the greatest quantities? What is hail? Theories as to its formation. 363. What are winds? How named? 364. What are the causes of winds? 365. What are regular winds? trade-winds? Cause? Explain periodic winds; monsoon; simoom; sirocco; land and sea breezes. What are variable winds? Causes. 366. What is a tornado? How caused? Explain the two kinds. 367. Explain the construction and working of the anemometer. 368. What are the advantages of the signal service? How is the telegraph an aid? Explain the method of making weather predictions. OPTICS. 369. Define optics. 370. Define light. 371. What are the two theories of light? Explain each. What is the difference between heat-waves and light-waves? sound-vibrations and light-vibrations? Illustrate light-vibrations. 372. What are luminous and illuminated bodies? Name and explain the principal source of light. 373. Define and illustrate a medium; transparent, translucent, and opaque bodies. 374. Explain and illustrate absorption of light. How shown in the atmosphere? 375. Define and illustrate a ray of light; pencil of rays; beam of rays. Prove that light in a homogeneous medium moves in straight lines. 376. What is a visual angle? Illustrate by figure. 377. How is a shadow formed? What is the umbra? penumbra? Illustrate shadows by figure. 378. Explain Roemer's method of ascertaining the velocity of light by Jupiter's moons. How great did he find the velocity to be? 379. What is meant by intensity of light? What is the law? What is a photometer? Explain its construction and the method of using it. 380. Explain reflection of light. What is irregular reflection? Examples. 381. Define incident and reflected rays; point of incidence; angles and planes of incidence and reflection. Illustrate by figure. 382. Give the laws of reflection. Illustrate by figure. 383. In what direction are objects seen? Illustrate by figure. 384. What is a mirror? Examples. What is the objection to mirrors which have amalgam backs? What is a speculum? 385. What is a plane mirror? Examples. 386. What is an image of an object? Explain how images are formed by plane mirrors. What makes up the whole image? 387. What is the nature of the image formed by a plane mirror? Define virtual and real images. 388. Explain multiple images. 389. Describe the kaleidoscope. How used? 390. Explain reflection by transparent bodies. 391. Describe the heliostat. How used? What is the difference between it and the porte lumière? 392. What is a concave mirror? Define vertex; centre of curvature; principal axis; principal section. 393. Define a focus; principal focus; principal focal distance. Illustrate the properties of a concave mirror by figure. What is a secondary axis? Explain spherical aberration. Advantage of parabolic mirrors. How can we develop heat by concave mirrors? 394. Illustrate conjugate foci by figure. Define them. What is a radiant? Enumerate the properties of the foci What occurs if the radiant is in a secondary axis? 395. Explain in detail the formation of images by concave reflectors. 396. Explain the formation of virtual images by concave reflectors. 397. Explain the formation of images by convex reflectors. 398. Explain refraction of light. Illustrate by figure. 399. Explain incident ray; point of incidence; refracted ray; angle of incidence; plane of incidence; angle and plane of refraction. 400. What is meant by the refractive power of bodies? What is the general rule of refraction? Give examples of the refractive power of different substances. 401, Give the laws of refraction. What is meant by the index of refraction? Illustrate the second law by figure. Illustrate index of refraction. 402. Give some experimental proofs of refraction. 403. Give some examples of refraction in water. What effect does refraction have on the heavenly bodies? The object is seen in the direction of what ray? 404. Explain and illustrate total reflection and the critical angle. 405. Give some examples of total reflection. Illustrate total reflection by figure. 406. Define mirage. How produced? Illustrate by figure. Give practical examples. 407. Explain and illustrate refraction with media having parallel faces. 408. Define a prism. How do prisms affect light? 409. Illustrate the course of luminous rays in a prism. 410. Define a lens. How made? 411. Give the classification of lenses. 412. Define centre of curvature; axis; optical centre. Explain how we find the perpendicular. 413. Explain the action of convex lenses on light. 414. Define principal focus; principal focal distance; spherical aberration by refraction. 415. Explain and illustrate conjugate foci. What is the radiant? Give position of the foci when the radiant has different positions. How are the foci situated in case of a secondary axis? 416. How is an image formed? Illustrate in detail the formation of images by convex lenses, with different positions of the object. When does the lens become a single microscope? 417. Illustrate the formation of images by concave lenses. 418. Explain burning-glasses. Give examples. 419. What kinds of mirrors were formerly used in lighthouses? What are the objections to mirrors? Illustrate the lenses used in lighthouses. How are different lighthouses distinguished from one another? 420. Define the solar spectrum. Explain in detail. Explain color as compared with pitch in sound. 421. What is recomposition of light? Explain the methods by which it can be produced. 422. Explain fully how the color of bodies is produced. 423. Define complementary colors. Illustrate. 424. What are subjective colors? Illustrate. Give Tyndall's explanation. 425. Explain and illustrate Fraunhofer's lines. 426. Describe in detail the spectroscope. 427. What is spectrum analysis? Illustrate. How were new metals discovered? How do we determine the existence of metals in the heavenly bodies? 428. What is interference of light? 429. Explain and illustrate Newton's rings. Examples of interference of light. 430. Explain diffraction of light. Examples. 431. What is double refraction? Illustrate fully. 432. Explain polarization of light. Illustrate. 433. Illustrate polarized light by tourmaline; by gratings; by reflection and refraction. Beautiful effects produced by interference of polarized light. 434. Explain the pincette. 435. Give some applications of polarized light. 436. What is a rainbow? Conditions of its formation? Two kinds? Explain by figure. 437. How is the primary formed from seven drops? Secondary? Give some more details of the bow. Examples of rainbows in icicles, etc. 438. What are the three properties of the spectrum? How determined? Illustrate by figure. 439. Explain fluorescence and calorescence. 440. Explain chromatic aberration. Illustrate. 441. What is an achromatic combination? Illustrate. 442. Name some varieties of optical instruments. 443. What is a microscope? Kinds? 444. What is a single microscope? Qualities of the image? 445. Of what does the compound microscope consist? Explain in detail. How is the magnifying power expressed? How is the object illuminated? Uses? 446. What is a telescope? Classes. Explain the first class. 447. Explain in detail the Galilean telescope. 448. Explain in detail the astronomical telescope. How do we find its magnifying power? What is the difference between the telescope and microscope? 449. Explain in detail the terrestrial telescope. 450. What is a reflecting telescope? 451. Explain Newton's. 452. Explain Herschel's. 453. What is the magic lantern? Explain in detail. 454. What is the polyrama? How are dissolving views obtained? Examples. What other lights are used instead of oil-lamps? 455. What is the photo-electric microscope? Explain in detail. Uses. 456. Explain and illustrate the solar microscope. 457. Define the camera obscura. Illustrate. The images are independent of what shape? Examples. 458. Explain the camera and lens. Illustrate their action and use. 459. Explain the artist's camera. Illustrate the course of the rays. 460. Explain and illustrate the pho tographer's camera. Define positive and negative pictures. 461. What is the eye? Explain in detail. 462. Explain the mechanism of vision. The inversion of the image. 463. How does the eye adapt itself to different distances and degrees of intensity? How long does an impression last upon the retina? 464. Define the terms near-sightedness and far-sightedness. How is each produced, and what is the remedy? 465. Why is not vision double? 466. What is the stereoscope? Describe its action and the method of using it. How can the lenses be made perfectly symmetrical? ELECTRICITY. 467. What is the nature of electricity? Name the three divisions. 468. What are natural and artificial magnets? permanent and temporary? 469. Explain the distribution of magnetic force. What are the poles? equator? Illustrate. Show that magnetism is exerted through intermediate bodies. 470. What is the action of one magnet upon another? 471. Give the law. 472. What is the effect when a magnet is broken? 473. Define magnetic and diamagnetic bodies. Examples. 474. Explain and illustrate magnetism by induction. 475. What is the coercive force? 476. Explain and illustrate the directive force of magnets. What are the real north and south poles of a magnet? 477. What is the magnetic meridian? What is meant by the declination of the needle? diurnal variations? perturbations? 478. Describe the compass. What is its use? How is the magnetic declination found at any place? 479. What is a dipping needle? How is the needle of the compass prevented from dipping? Show the use of the dipping needle. Illustrate with bar magnet. 480. Explain how magnets are made by terrestrial induction. 481. How are magnets made by friction? single touch? separate? double? 482. What is a magnetic battery? armature? Use? 483. Give an outline of the history of electrical discoveries. Explain Gilbert's experiments and the manner of making them. What is the derivation of electricity? 484. Define the electroscope. Describe the electrical pendulum. What is its use? 485. Prove that there are two kinds of electricity. Give names. 486. Describe in detail the gold-leaf electroscope? 487. Explain the method of using it. 488. What is the law of electrical action? 489. Define conductors; insulators. Give illustrations and examples. 490. Explain fully the hypothesis of two electrical fluids. Explain electricity as energy. 491. When two bodies are rubbed together, what results? Give list of bodies that produce negative or positive electricity, according to the order of rubbing. 492. Explain how electricity can be produced otherwise than by friction. 493. Explain how bodies are electrified. 494. Show that electricity tends to accumulate on the surface of bodies by the hemispheres and by Faraday's experiment. 495. What is meant by tension of electricity? Illustrate. 496. Illustrate by the proof-plane the power of points in electricity. 497. What is meant by induction? Illustrate fully. 498. What is Faraday's theory? 499. What is the electrophorus? Describe it. How used? 500. What is the electric machine? By whom invented? Describe in full. 501. Explain its use. 502. What is the principle of Holtz's machine? Describe in detail. Explain its action. How affected? 503. What is Carré's dielectric machine? hydro-electric? 504. What precautions are necessary in using the machine? 505. What is an electrical condenser? 506. Describe the Leyden jar. How charged and discharged? 507. What is an electric battery? How charged? 508. Explain the Leyden jar with movable coatings. 509. What is an electrical spark? How produced? What is an electrical shock? When felt? Explain the production of the spark. 510. How is the electrical stool used? 511. What is the electric chime? Explain its action. 512. What is the electric image? Explain its action. 513. Explain the effect of points in electrical action. 514. What is the electrical wheel? Explain its action. 515. What is the velocity of electricity? Illustrate the duration of the spark. 516. What is the electrical egg? Describe its action 517. What is the electrical square? Explain its action. 518. Пlustrate the heating power of electricity by burning ether and the battery. 519. Show mechanical effects by card and Leyden jar. 520. Show chemical effects by pistol. 521. What are the physiological effects of electricity? Give examples. 522. Show the identity of lightning with the electric spark. 523. Explain atmos- 531. What is dynamical electricity? Why so called? Origin of the terms galvanic 551. Name the effects of the galvanic battery. 552. Explain and illustrate the physio- 559. Show the relation between magnetism and electricity. 559. Explain and illus- 566. Define an electro-magnet. How made? What property has a soft-iron arma- 579. Explain and illustrate induction by currents. 580. Give the laws of induced |