846 



INDEX. 



MOU 



on, 49, 50, &c.; of falling bodies, 58; 



of projectiles. 65 

 Mouth instruments, 382 

 Multiplier, 747 

 Multiple echoes. 344 ; images formed 



by mirrors, 431 

 Musical intervals, 349 ; scale, 349 ; 



notes, 348 ; pitch, 347 ; quality, 368 



"VTEEDLE, magnetic, 739 ; dipping, 



ll 743 ; astatic, 745 



Negative electricity, 556 



Negative pole of a battery, 653 



Neutral equilibrium, 106 



Newtonian telescope, 532 



Newton's disc, 541 



Nippers, 28 



Nodal points, 360 ; lines, 368 



Nodes, 360 



Noise, 344 



Non-conductors of electricity, 559 



Normal boiling point of water, 767 



Notes, in music, 344 ; pitch of, 347 ; 



quality of, 368 ; rate of vibration of, 



349 

 Nut of a screw, how to cut, 94 



OCTAVE, 348 

 Oil-globule, form of, suspended in 



a liquid, 11 

 Opaque, 414 

 Opera-glasses, 527 

 Optic nerve, 515 

 Optics, 409 

 Optical instruments, 514; images, 431; 



delusions, 549 

 Organ-pipes, 382 

 Oscillations of pendulum, 1 24 

 Overtones, 363 ; of tubes, 384 



T)AINTS for wooden scale, 236 



JT Pane, Franklin's, 619 



Parabola described by projectiles, 69 



Parallelogram, area of, 3 



Pastille, how to make, 12 ; cracking of 

 glass by, 13 



Pendulum, laws of, 123 ; construction 

 of temporary, 50, 58 ; Foucault's ex- 

 periment, 130 ; electrical, 553 



Penumbra, 416 



Percussion, heat produced by, 827 



Permanent gases, 809 ; magnets, 736 



Persistence of visual impressions, 546 



Phenakistoscope, 547 



EEF 



Photometer, Rumford's, 422 ; Bunsen's, 

 424 



Pigment-colours, 542 



Pinchcocks, how to make, 20 



Pipes, vibration of air in, 377 



Pipette, 11 



Pitch, 344 



Plates, vibrations of, 368 



Pliers, round and flat, 20 



Pneumatic syringe, 828 



Point, boiling, 765, 802 ; freezing, 764 



Points, action of, 588 



Poles, magnetic, of the earth. 741; of a 

 magnet, 704 ; of an electric battery, 

 653 ; mutual action of, 70/7 



Pores. 30 



Porosity, 29 ; of liquids, 30 ; of gases, 

 31 ; experiments on, 30, 31 



Positive electricity, 556 



Positive pole of a battery, 653 



Press, hydraulic, 162 



Pressure of liquids, 161 ; construction 

 of apparatus for showing, 167; atmo- 

 spheric. 228; heat produced by, 827; 

 of air on floating bodies, 269 



Primary coil, 749 ; current, 749 



Prince Rupert's drops, 773 



Prism, refractive action of, 458 ; trian- 

 gular, volume of, 6 ; construction of, 

 463 



Projectiles, motion of, 65 



Proof-plane, 576 



Pulley, 87 



Pump, air, 270; suction, 291; forcing, 

 294 ; condensing, 289 ; how to con- 

 struct. 297 



Pupil, 515 



AUALITY of sound, 368 



pADIATION, 809 



-ft Radiating power, 811 



Rarefaction in air-pump, 277 



Rays, luminous, 38, 810 ; heat, 810 



Reaction of efflux, 199 ; of gases, 301 



Reaction-wheels, 200 



Real image, 440 ; expansion, 781 



Reaumur scale, 762 



Receiver of air-pump, 272 



Rectangular solid, volume of, 5 



Reed instruments, 389 



Rt! fleet ing power for heat, 811 ; tele- 

 scope, 532 



Reflection of light, 427 ; laws of, 429 ; 

 verification of laws of, 428 ; of heat, 



