Full text of "Principles of Physics, Or, Natural Philosophy: Designed for the Use of Colleges and Schools"

Skip to main content

Search the history of over 327 billion web pages on the Internet.

search Search the Wayback Machine

Featured

texts All Texts latest This Just In Smithsonian Libraries FEDLINK (US) Genealogy Lincoln Collection Additional Collections

eBooks & Texts

Top

American Libraries Canadian Libraries Universal Library Community Texts Project Gutenberg Biodiversity Heritage Library Children's Library

Open Library

Public Lab Books to Borrow

Featured

movies All Video latest This Just In Prelinger Archives Democracy Now! Occupy Wall Street TV NSA Clip Library

TV News

Top

Animation & Cartoons Arts & Music Community Video Computers & Technology Cultural & Academic Films Ephemeral Films Movies

Understanding 9/11

News & Public Affairs Spirituality & Religion Sports Videos Television Videogame Videos Vlogs Youth Media

Featured

audio All Audio latest This Just In Grateful Dead Netlabels Old Time Radio 78 RPMs and Cylinder Recordings

Live Music Archive

Top

Audio Books & Poetry Community Audio Computers & Technology Music, Arts & Culture News & Public Affairs Non-English Audio Podcasts

Librivox Free Audiobook

Radio Programs Spirituality & Religion

Featured

software All Software latest This Just In Old School Emulation MS-DOS Games Historical Software Classic PC Games Software Library

Internet Arcade

Top

Community Software APK MS-DOS CD-ROM Software IPA Software Software Sites Tucows Software Library

Console Living Room

Shareware CD-ROMs CD-ROM Images ZX Spectrum Vintage Software DOOM Level CD ZX Spectrum Library: Games CD-ROM Software Library

Featured

image All Image latest This Just In Flickr Commons Occupy Wall Street Flickr Cover Art USGS Maps

Metropolitan Museum

Top

NASA Images Solar System Collection Ames Research Center

Brooklyn Museum

web texts movies audio software image logo Toggle navigation ABOUTCONTACTBLOGPROJECTSHELPDONATEJOBSVOLUNTEERPEOPLE

search

Search metadata Search text contents Search TV news captions Search archived web sites

Advanced Search

upload personSIGN IN

ABOUTCONTACTBLOGPROJECTSHELPDONATEJOBSVOLUNTEERPEOPLE

Full text of "Principles of Physics, Or, Natural Philosophy: Designed for the Use of Colleges and Schools"

See other formats

This is a digital copy of a book that was preserved for generations on library shelves before it was carefully scanned by Google as part of a project to make the world's books discoverable online.

It has survived long enough for the copyright to expire and the book to enter the public domain. A public domain book is one that was never subject to copyright or whose legal copyright term has expired. Whether a book is in the public domain may vary country to country. Public domain books are our gateways to the past, representing a wealth of history, culture and knowledge that's often difficult to discover.

Marks, notations and other marginalia present in the original volume will appear in this file - a reminder of this book's long journey from the publisher to a library and finally to you.

Usage guidelines

Google is proud to partner with libraries to digitize public domain materials and make them widely accessible. Public domain books belong to the public and we are merely their custodians. Nevertheless, this work is expensive, so in order to keep providing this resource, we have taken steps to prevent abuse by commercial parties, including placing technical restrictions on automated querying.

We also ask that you:

+ Make non-commercial use of the files We designed Google Book Search for use by individuals, and we request that you use these files for personal, non-commercial purposes.

+ Refrain from automated querying Do not send automated queries of any sort to Google's system: If you are conducting research on machine translation, optical character recognition or other areas where access to a large amount of text is helpful, please contact us. We encourage the use of public domain materials for these purposes and may be able to help.

+ Maintain attribution The Google "watermark" you see on each file is essential for informing people about this project and helping them find additional materials through Google Book Search. Please do not remove it.

+ Keep it legal Whatever your use, remember that you are responsible for ensuring that what you are doing is legal. Do not assume that just because we believe a book is in the public domain for users in the United States, that the work is also in the public domain for users in other countries. Whether a book is still in copyright varies from country to country, and we can't offer guidance on whether any specific use of any specific book is allowed. Please do not assume that a book's appearance in Google Book Search means it can be used in any manner anywhere in the world. Copyright infringement liability can be quite severe.

About Google Book Search

Google's mission is to organize the world's information and to make it universally accessible and useful. Google Book Search helps readers discover the world's books while helping authors and publishers reach new audiences. You can search through the full text of this book on the web

at |http : //books . google . com/

r

^

>

/Pi^t-,

^'-'^liiiX J,

(Pig. 676.)

Doum Plati uonuoAi. Maioiimi,

MASM itA TBI Unmam or BmISST.

PRINCIPLES

OF

PHYSICS,

NATURAL PHILOSOPHY;

DE8I0KED FOR THR

Sst ni (SCoUeges anlj Scfe00ls*

BY

BENJAMIN SILLIMAN, Jr., M. A., M. D.,

PROFIBSOR or GENERAL AND APPLIED CHEMISTRY IN YALE COLLEGB.

SECOND EDITION,

REVISED AND REWRITTEN.

Iftt) %thtn Ji^unbttis tLxih dTbtnts-Q^too illustratiatiir.

PHILADELPHIA:

PUBLISHED BY THEODORE BLISS & CO.

1866.

^r-

"*3 4 ., 3 T 'OJ

Bntered, Meordhig to Act of Oongreni, tn the year 1800, bj

H. a PECK A THXO. BU88,

in the Clk*i Ofllee of the District Govt of the EMtern District of PenniylTaDia.

MLkM ft DUSKHBXBT, STnCOTTPIM.

RMAH 4 PRIirrEM.

y .. ,V-i 'yoLSV

PREFACE TO THE SECOND EDITION-

Mant UDportant changes have b^en made in tbe present edition, designed to adapt the work more fully to the wants of the higher veminaries, where mathematical dcmoneirations are required of the olaases in Natural Philosophy. With this view, tho two first Parta have been almost whoUy re written ^ and upon a different plan of arrangement. Some eubjects which were perhaps too fully treated in the finst edition, as, for example, CryBtallographj, have. been reduced, while others have been expanded to meet the just propor- tions of a harmonious treatment. These remarks apply also to Fart Third (the Physics of Imponderable Agents), and especially to Optics and Heat. In the latter chapter some topics have been omitted which are more appropriately treated in Chemistiy.

The mathematical demonstrations, while they are designed to be M simple as possible consbtent with exactness, are believed to be M full and rigorous as are demanded in institutions where only geometric and algebraic methods are used. Analytical methods have not been introduced, as the book was not designed for the comparatively limited number of colleges where the higher mathe- matics are employed in teaching Physics.

The questions at the foot of the pages in the first edition, have been omitted, to gain space for a considerable number of practical problems (mostly original,) designed to exercbe the student in the application of the principles and formulas found in the text. To id in the solution of these, and to assist the teacher in the oon- Btmetion of additional problems, numerous physical Tables have been aided in the Appendix.

The plan of using two kinds of type, resorted to in the first

s.

VI PREPAGS TO THE SECOND EDITION.

edition, has been continned with more particularity in this The book is thus adapted to the use of the general reader, and to stu- dents who seek only a knowledge of general principles.

These changes and additions, the author belieyes, entitle this edition more fully to the encomiums bestowed on the first by many of the ablest physicists and most experienced teachers in this country. By the liberality of the publishers, numerous additions have been made to the wood-cuts, while new designs, in numerous cases, replace those of less beauty in the first edition.

The design has been, in this edition, to give to all the depart- ments of physical science a just proportion of space, in harmony with the general scope of the book. The subject of Mechanics and Machines (upon which so many excellent special treatises exist) has, there. ^'''* condensed into a smaller proportionate space than it usually occupies in American treatises on Natural Philosophy; while ch fundamental subjects as Motion, Force, Gravitation, Elastic ly, Tenacity, and Strength of Materials, are considered at more length.

The author has freely availed himself of all the sources of infor mation within his reach. A list of the works chiefly used in the preparation of this edition is appended ^to which should be added the chief foreign journals, and transactions of learned societies which have been resorted to for the original memoirs quoted on a great variety of topics. He is also particularly indebted for good counsel to many scientific and personal friends, the infiuence of whose criticisms on the first edition they will find frequently i]> the present. More than to all others is he indebted to Dr. M. C White, of New Haven, for his constant attention, both in the preparation of new matter and in the revision of the press.

He also takes pleasure in again acknowledging his obligations to Prof. C. H. Porter, of Albany.

For a final revision of the sheets, and the detection of a number of errors which had escaped previous proof-readers, the author is indebted to Mr. Arthur W. Wright, Assistant Librarian of Tale College.

Fuller references have been added, especially to American autho- rities ; and the author hopes no apology is required for the frequent references to the American Journal of Science, which is supposed

VBMWAOm TO THX 8100ND BDITIOX. Til

to be t work acoemible to all Ameriean t vshen, wMle the Euro- pean joamala are rarely so; and references to these would, there- fore, be of little practical use to the great majority of readers of anch a treatise as this.

As no table of errata is given (all errors thus far discorered being corrected), the author will esteem it a great &yor if any person using the book will communicate to him direct any errors of ict or figures which may be discovered.

New Hatxn, Odober 15, 1860.

UST or TBI PRINCIPAL W0KK8 V8EO IN PREPARIKO THIS UITIOW.

CooKB. Cliemical PhjsicB. Boston, 1860.

Daguin. Trait6 de Physique, torn. I., II., and III. Paris and Touluuse, 1855- 1859.

De la Rive. Treatise on Electricity, 3 volumes. London, 1853- 1858.

Ganot. Traits de Physique. Paris, 1859.

GooDH'iN. A Collection of Problems and Examples. Cambridge, England, 1851.

Jaxin. Cuurs de Physique, torn. I. and II. Paris, 1858-1859.

Kaul. Mathemntische Aufgaben aus der Physik. Leipzig, 1857.

Miller. Chemical Physics. London, 1855.

ML'LLBR. Lehrbuch der Physik und Meteorologie. Braunschweig, 1857.

Potter. An Elementary Treatise on Optics, 2 Parts. Londcn, 1851.

Potter. An Elementary Treatise on Mechanics. London, 1855.

Potter. PhyHical Optics. London, 1856.

Wernicke. Lehrbuch der Mechanik. Braunschweig, 1858.

Ml

FEOM PREFACE TO THE FIRST EDITION.

Tnit band'b wk hfi3 beeu pfepn?ed with a view to gire a fair eipoai^ tion of the present condition of the BeveraL depnrtinCDts of PhjBicB. ^ Accuracy of Bt&temcQt, fullness of lUuatr&tioii, ooncUenesB of expression ^ and a record of the latei^^t and moHt reliable progT-es of science in tbeae departmeota, lia?c been the leading objects in h% prc^paration.

Only those who have attempted to harmonize and present in due proportion the whole of so vast a subject as this, in a compendious form, can fully appreciate the labor and difficulties which attend it.

Without claiming for the present volume any credit more than belongs to a faithful digest and compilation from the best authorities in modem science, it is hoped that it will be found suited to the wants of a large class of both teachers and students. No pains have been wanting to secure accuracy both in fact and mechanical execution. The publishers have spared no expense to illustrate the book with a profusion of wood cuts. Many of these are original designs, or are reduced from larger drawings b^ photography and others have been selected with care from the best standard authors. Whenever it was possible, reference has been had to original memoirs in Journals and Transactions, and in this way many errors current in works of inferior authority have been corrected. With but few excep- tions, references to foreign memoirs have been omitted in the text, as their insertion could profit only a very small number of readers, and might seem pedantic. Not so with respect to names of discoverers of important principles and phenomena. A great number of names of , these will be found in the text, in their proper places, and not unfre- quently the dates of birth, or death, or both, are given.

Every teacher must have observed that an abstract principle is often fixed in the memory by the power of associated ideas, when it is eonnected with a date or item of personal interest, as the attention is

(9)

Z PREFAOB TO THB FIRST EDITION.

awakened by the dramatio far more than by the didactic. Hence it has been thought jadicions to introduce numerous important dates in the history of science.

It gives me great pleasure to acknowledge many obligations to Prof. Oharlis H. Portbr, M. A., M. D., of Albany (some years my assistant), for his constant and most important assistance in the compilation and editing of this book. Preoccupied as my own dme has ften, I should not at times have found it possible to proceed without his valuable assistance and excellent judgment. Dr. M. C. Whits, of this town, has also rendered me important aid, especially in Optics, and in the revi* sion of the press.

Nsw Havw, Covv., OeL 15, 1868.

CONTENTS.

PART FIRST.

PHYSICS OF SOLIDS AND FLUIDf

CHAPTER I.

INTRODUCTIOH.

Matter Observation and experiment, 1 Law, theory, and bjpotheflis Indao- tire philosophy Force, 2 The properties of matter are general, or specific The changes in matter are physical, or chemical, 3 Physical and chemical properties of matter Physics and chemistry Vitality, 4 Light, heat, and electricity, 5.

CHAPTER IL

OBNEBAL PRnVOIPLES.

{ 1. Definitions and Qenerai Properties of Matter I. Essential PROPERTIES The essential properties of matter Magnitude or extension, 5 Impenetrability The three states of matter II. English and French 8T8TBM8 OF KBABURE8 Units of measure, 6 English units of length The French system of measures, 7 III. Accessort properties of matter Dirisibility, 8 Minnte dirision in the animal and regetable kingdoms, 9 Atoms, molecules Compressibility, 10 Expansibility Physical pores, 11 Sensible pores Mobility, 12 Inertia ^Action and reaction, 13.

i 2. Of Motion and Force I. Motion Varieties of motion, 13 Time and Telocity Uniform motion Variable motion, 14 Motion nniformly raried, 15 Compound motion, 10 Parallelogram of Telocities II. Of FORCES Definition of force Forces are definite quantities Weight Unit of force Dynamometers, 17 Equilibrium Statical and dynamical forces Direction of force, 19 Measure of forces Mass Propositions in regard to ftvoes, 20~Momeiitiim, 21 IIL Comfobitiom of FOBCES^System of foroM

XU CONTENTS.

Componenta and rtihultant The parallelogram of forces, 22 Examples of the composition of motion and force Parallel forces Resultant of unequal parallel forces, 25 Resultant of two parallel forces acting in opposite direc- tions Couples, 26^Two forces not parallel and applied to different points The resolution of forces Example of the resolution offeree, 27 IV. Curvi- linear MOTION CENTRAL FORCES Of curvilinear motion Centrifugal and centripetal forces, 28 Examples of the action of centrifugal force Experi- mental demonstration of the effects of centrifugal force, 29 The centrifugal drying machine for laundries, 31 Analysis of the motion produced bj central forces, 32 Bohnenberger's apparatus Parallelogram of rotations, 33 The gyroscope, or rotascope, 36 Problems on weights and measures Problems on motion, 37.

CHAPTER III.

GRAVITATION.

1 1. Direotion and Centre of Oravity Definition Law of universal gravitation, 38 Direction of terrestrial attraction Centre of gravity, 39 Point of application of terrestrial attraction, 40 Centre of gravity Corolla- ries, 41 Centre of gravity of regular figures, 42 Centre of gravity lying without the body Equilibrium of solids supported by an axis Equilibrium of solids placed upon a horizontal surface, 43 Centre of gravity in bodies of unequal density in different parts Equilibrium of bodies supported in more than one point, 44.

{ 2. Laws of Falling Bodies Gravity is a source of motion The laws of falling bodies are five, 45 Whole space described by a falling body, 47 Verification of ttf ' '^i of falling bodies Atwood's apparatus, 48 Morin's apparatus Applicatitr.. of the laws of falling bodies, 50 Descent of bodies on inclined planes, 51 Descent of bodies on curves Brachystochrone, or curve of swiftest descent Action and reaction of a falling body, 52.

{3. Measure of the Intensity of Gravity I. Pbndulvm The pendulum Properties of the simple pendulum, 53 Isochronism of the pendulum, 54 Fomralsd for the pendulum Propositions respecting the simple pendulum, 55 The physical or compound pendulum Centre of oscillation, 56^Application of the pendulum to the measurement of time, 57 Cycloidal pendulum Physical demonstration of the rotation of the earth l>y means of the pendulum, 58 The pendulum applied to the study of gravity, 59 Use of the pendulum for mea- suring the force of gravity Value of ^ in these experiments, 60 Seconds pen- dulum II. Modifications or terrestrial gravity and their cattses. The intensity of gravity varies with the latitude, 61 Influence of the earth's figure upon gravity, 62 Exact dimensions of the earth Sensible weight varies in different localities Effect of the earth's rotation on gravity, 64 Demonstra- tion, 65 ^Variation of gravity above the earth and below its surface^Below the earth's surface, 66.

2 4. Mass and Weight Mass ^Weight Density Specific weight, 67 French system of weights, 68 English and American system of weights Estimation of the density of the earth by experiment, 69 The inference, 71.

{5. Motion of Projeotiles Projectiles, 71 The ballistic pendulum^ Problems Falling bodies, 73 Descent of bodies on inclined planes Central foreas Pendalani and Gravity, 74 Flight of ProJeetilM, 75.

OONTKIITB. XIU

CHAPTBB IV.

THBORT OW MAOHIHBBT.

1 1. ICaohlnas Principle of Tirtual relocitiet, 76 Haohine, power, weight Bqaillbriom of meohines, 76 Utility of mftohines Relatioii of power to weighty 77 ^Adaptation of the power to the weight in miehinery Y\a Tir%, or living foree, 78~IllastraUoni of ris viva Impact and iti reanlta Impact eonaidered with reference to momentum, 80 ^Impact considered with reference to vii Tire^ 81 Preeiare produced by impact ^DettmctiTe elTectf of impeoty 82.

1 2. Meohanioal Poweis The lerer, 88 Conditions of equilibrium in the lever Compound levers Application of the lever, 84 The scale beam The steelyard, 85 Examples of compound levers, 88 Roberval's counter platform balance, 87 ^The wheel and axle, 88 Trains of wheel-work, 89*-Analysis of train of wheel-work, 90 The pnll^ Fixed pulley MovaUe pull^ Com- pound pulleys, 01 The inclined plane ^Application of the power parallel to the length of the inclined plane, 93 Application of the power parallel to the base of the inclined plane, 94 Application of the power in some direction not parallel to any side of the plane The wedge Application of the wedge, 95 The screw, 96 Mechanical efficiency and applications of the screw The endlcM screw, 97.

2 3. Btrength and PowerAnimal strength Strength of men Horse- power machines, 98 Table of the comparative strength of men and other animals Steam-power, 99 Perpetual motion, 100.

2 4. Impediments to Motion Passive resistances Sliding friction Starting friction Friction during motion, 101 C* aVs apparatus for determiuing starting friction Results of Coulombs ^poriments on Ptartiug friction, 102 Rolling friction CoulumVs apparatus for determining rolling friction Results of Coulomb's experiments on rolling friction, 104 Mr. Babbage's experiment Advantages derived from friction Rigidity of ropes Resisunces of fluids, 105- Actual and theoretical velocities Ballistic curve, 106 Pboblems Vis viva The lover Wheel and axle, 107- -The pulley- Inclined plane The screw Resistance, 108.

2

ZIV CONTENTS.

PART SECOND.

THE THREE STATES OF MATTER.

CHAPTER I.

MOLECULAR FORCES.

Cohesion and repolsion Repulsion, 109 Examples of cohesion among sclids, 110 Cohesion in liquids and between liquid gases and solids, 111 Between gases and solids, 112.

CHAPTER II.

OF SOLIDS. MOLBCDLAR FORCES ACTING BETWEEN PARTICLES OF LIKE KUTDB.

i 1. Properties of Solids The charaoteristio properties of solids Struc- ture of solids, 113.

{ 2. Crystallography Conditions of crystallisation, 114 Amorphism Crystalline forms ^Definitions, 115 Systems of crystals, 118 Modified forms, 120 Compound crystals, 121 Cleavage Determination of crystalline forms, 122.

i 3. Blasticity Elasticity of solids, 122 Elasticity of tension and compres- sion, 123 Coefficient of elasticity, 124 Elasticity of flexure, 125 Applica- tions M. Bourdon's metallic barometer, 127 The Aneroid barometer Elasticity of torsion, 128 Coulomb's laws of torsion, 129 Torsion of rigid bars Limit of elasticity, 130 Change of density produced by tension, 131.

i 4. Strength of Materials Laws of tenacity, 131 Johnson's results Tenacity of regetable and animal substances Resistance to pressure in columns, 132 The lateral or transverse strength of materials, 133 Practical applications, 134 General estimate of the strength of beams The Britannia Tubular Bridge, 136 The Victoria Tubular Bridge Limits of magnitude, 137.

{ 5. Properties of Solids depending on a permanent displace- ment of their Molecules Malleability Ductility Hardness, 138 Brittleness Hardening, Temper, Annealing, 139 Colors of tempered steel Tempering by a bath Temper of glass Prince Rupert's Drops, 140 Tem- pering copper and bronze Hammering, 141 Changes of structure afiecting the mechanical properties of metals, 142.

J 6. Collision of Solid Bodies Motion communicated by collision, 142 Direct impact of elastic bodies Modulus of elasticity, 143 Velocity of elastic bodies after direct impact, 144 Scholium, 145 Transmission of shock through a series of elastic biUls Experimental illustration of elasticity

CONTENTS. XV

Problems Elasticity of tension Elasticitj of flexure Tenacity Tuns verse atrength, 146 Impact of elastic bodies, 147.

m

CHAPTER III.

OK FLUIDH. HYDROOYNAlfJCS.

2 1. Hydrostatics I. Distinouishino properties of liquids Definitione Fluids Hydrodynamics Mechanical condition of liquids Elasticity of liquids Compressibility, 1-18 Elasticity Consequences, 150 11. Trans- MisMioir OF PRESSURE IN LIQUIDS Liquids transmit pressure equally in all directions, 151 The Bramah hydrostatic press, 152 Uses in the arts Pres- sure of a liquid on the bottom of a rcssel, 153 Upward pressure, 154 Pres- sure on the sides of a rcssel Pascal's experiment with a cask, 155 The water bellows, or hydrostatic paradox Total pressure on the walls, 156 Total pres- sure on the bottom and sides of a yessel, 157 The centre of pressure, 158 Pressures rary as the specific gravities of liquids III. Equilibrium of LiQViDS The conditions of equilibrium in liquids, 159 Equilibrium of liquid:^ when freed from the influence of gravity The experiment of Plateau Equilibrium of a liquid in communicating vessels, 160 Equilibrium of liquid?' of different densities in communicating vessels Demonstration Tlie spirit level, 1(51 Artesian wells IV. BuoYxVNCY op liquids Theorem of Archimedes, 102 Another demonstration of Archimedes' principle Floating bodies, 164 Examples Equilibrium of floating bodies, 165 Neutral c(|iii- librium Unstable equilibrium, 1G6 Stable equilibrium The metaoentre, IfiT V. Determination of specific grwitv The problem stated Methods Specific gravity by the hydrostatic balance, 16R Examples, 169, 170 Spe- cific gravity bottles, 170 Example Specific gravities by hydrometers or areometers Nicholson's hydrometer or areometer, 171 Gay Lussac's and Beaurar's hydrometers, 172.

{ 2. Hydraulics I. Motion of liquids Definition Pressure of liquid.^ upon the containing vessel, 173 Appearance of the surface during a dissohar^^t; Theoretical and actual flow, 174 Reaction of the escaping vein Barker's mill, 175 Flow Theorem of Torricolli Deductions from the Torricellian theorem, 17C Demonstration of the theorem of Torrieclli, 177 The inch l, IBO I>tofwfa>ti!W nf Hit iwilpotjtiilllj r tolid^* 4S1 OoftdMtiUlS^ of iiliM% JcttM'oBiMlIlillillr of iiTiteii Owidadtibility of woo^, iSS^TftnUioBo piodMMl ^ o o adte ol ta i of hoi*-- CmimMmHf of liqgidi Ow J i irtl|iait^EU;,M*, 4i4.-lr,>, ounstanees influeaemg the boiliag point, 466 The caUaasy ymyU^i^ttmlk.

ZXll CONTENTS.

lin'fl palse glass Usefal applications in the arts Measurement of heigbU by the boiling point Hypsometer, 461 High pressure steam Production of cold by evaporation, 462 Twining's ice machine Latent heat of steam, 463 -Latent and sensible heat of steam at different temperatures Mechanical force developed during evaporation, 464 Liquefaction Distillation Distil- ling apparatus Physical identity of gases and vapors Theory of the lique- laction and solidification of gases, 465 Methods of reducing gases to liquids Later researches of Faraday Thilorier's and Bianchi's apparatus for con- densation of gases, 466^PropertieB of liquid and solid gases Latour's law, 467 Density of vapors, 468.

1 9. Spheroidal condition of Liquids Spheroidal state Illustration of the spheroidal state Noticeable phenomena connected with the spheroidal state, 468 Spheroidal state produced upon the surface of liquids A liquid in a spheroidal state is not in contact with the heated surface beneath, 469 A repulsive action is exerted between the spheroid and the heated surface The causes which produce the spheroidal form, 470 Freezing water and mercury in red-hot crucibles Remarkable phenomena connected with the spheroidal state Explosions produced by the spheroidal state, 471 Steam boiler explosions Familiar illustrations of the spheroidal state, 472.

{ 10. The Steam-Engine Historical The eolipile First steamboat Savary's engine, 473 Papin's steam cylinder Newcomen's engine, 474 The atmospheric engine Watt's improvements in the steam-engine, 475 The low pressure or condensing engine, 476 The high pressure engine The cut off, 477 Steam boilers Mechanical power of steam Horse-power, 478 Evapo- rating power and value of fuel, 479.

J 11. Ventilation and Warming I. Ventilation Currents in air and gases, 480 Draught in chimneys, 481 Reversed draughts and omoky chimneys Products of respiration and combustion, and necessity for ventilation, 482 The quantity of vapor given off by the body The quantity of air required for good ventilation Products of gas illumination, 483 The actual ventila- tion of buildings is a practical problem Stone's ventilating shaft, 484 Cold currents produced by ice Refrigerators Cowls Emerson's ventilators, 485 The supply of fresh air in dwellings II. Warming The artificial tempe- ratures demanded in cold climates The open fire, 486 Hot air furnaces, 487 Heating by hot water Perkins' high pressure hot water apparatus, 488 Gold's steam heaters The radiators, 489 The boiler of Gold's steam heater, 490.

2 12. Soarces of Heat Sources of heat I. Mechanical sources of heat Friction, 490 Quantity of heat produced by friction Circumstances which vary the quantity of heat developed by friction Illustrations and application of the heat developed by friction, 491-;-Co^pres8ion Percussion Capillarity, 492 II. Physical sources op heat The sun Quantity of heat emitted by the sun Extremes of natural temperature, 493 Terrestrial radiation Origin of terrestrial heat Atmospheric electricity, 494 III. Chemical sources of heat Chemical combination Combustion On the cause of the heat gene- rated by combustion The amount of heat developed by chemical action, 495 The pyrometrical heating effect of a substance, 496 Relative value of fuel Combinations in the humid way Animal heat; warm and cold-blooded animals, 497 The cause of animal heat Temperature of vegetables, 498.

1 13. Correlation of Physioal Forces~I. Mechanical bquitalknt of

CX)NTJUITS. ZXIU

WMAf Bdariwiaflwt and fore*, 498 Unit of mMynuikil tho fi>oi-poiind BtlinBlmHm of iSbm Btehuikal qviralflot of hoftft Bofiilta of Jonle'f f 409 OeMfantoiia dodiMod from Jonlo*! exporinMnts. IL Dt- T 9W BBAV Tbo dyiiAiiileal thooiy of heat Motloni of the I In A* itate or Tolnmo of bodies, 600 IIL Avaloot or -Yibntloiit prodaeing heat and Ughi Impreeiioiig of light ^d teaty Ml ^Bodlw beoone Imninoiu by incuidefeence, 502 Heftt and light pvednood by ehewliral and meBhanioaJ aetion Dilatation and ohange of atate, M3 Ckanga of itata prodnoed bj heat Qnali^ of heat ohanged bj abaorp- tioa and radiation, 604 Diflforence between qoantl^ and intenaitgr of beat Ceaohwiany 606 PnoBiAMt o* bbat Thennometeriy 600 Ezpanrion le hmif 607 Tenaion of raoora Ventilation and warming^ 608.

CHAPTBB m.

BLBOTBXOITT.

.609

{1. Kagnetlo Bleotrioitj I. VnovwamB of maoitets Lodeitone Natnral magnate ArtificiEl magnets, 609 Magnetic needles Distribution of the magnetic force Polarity, 610 Magnetic phantom Magnetic carves Magnetic figures, 51 1 Anomalous magnets Attraction and repulsion Mag- netism by contact, 512 Magnetism in bodies not ferruginous II. Mach** irxnc ivnucnoN on ivvLXjmncm Induction, 513 Theoretical considerations Theory of two fluids, 614 Coercitive force IIL Terrestrial magnetism Magnetic needle Directive tendency, 515 The mariner's compass, 516 The astatic needle Magnetic meridian Declination or variation, 517 Varia- tion chart Isogonal lines, 518 Daily variations of the magnetic needle The annual variation Dip or inclination, 520 The action of the earth's magnetlam Dipping needle, 521 Inclination map, or isoclinal lines, 622 Magnetic intensity, 523 Isodynamic lines, 524 The inductive power of the earth's magnetism System of simultaneous magnetic observations, 525 Lines of magnetic force Atmospheric magnetism, 526 Notions of the origin of the earth's magnetism IV. Production or magnets Artificial magnets, 527 The circumstances affecting the value of magnets Magnets by touch, 528^ Horse-shoe magnets, 529 Magnets by electro-magnetism Compound mag- neta, 530 Magnetism of steel by the sun's rays To deprive a magnet of its power, 531. 1 2. Statical or Frlotional Eleotrioity I. Electrical phenomena Definitions, 531 The chief sources of electrical excitement Electrical effects ^Attraction and repulsion, 532 Vitreous and resinous, or positive and nega- tire electricities Electroscopes, 533 Conductors of electricity Good con- ductors Bad conductors Insulation, 534 The earth is the great common raaerroir Theories of electricity, or electrical hypothesis Franklin's single- fluid hypothesis, 535 The hypothesis of Symmer, or Du Fay, 536 Electrical tanalon Electrical currents are either momentary or permanent Path and raloeity of electric currents, 53711. Laws or electrical roRCES and nii- nuBvnoN or electricity upon the suRrAcs or bodies Coulomb's laws Torsion electrometer, 538 Demonstration of the first law Demonstration of Cba saeond law Sir Wm. S. Harris Proof-plane, 5)9 Electricity residea

XXIV CONTENTS.

only on the outer turfacet of excited bodies, 540 Distvibation of electricity The power of points 541 The loss of electricity in excited bodies III. !- DUCTiON OF ELECTRICITY Electrical influence or induction, 542 The laws of induction Induction is an act of contiguous particles, 543 The attractions and repulsions of light bodies, 544 Electrometers Cavallo's, Volta's, and Bennett's IV. Electrical machines The electrophorus, 545 The cylinder electrical machine, 546 Amalgam Kamsden's plate machine, 547 The Ame- rican plate electrical machine Large electrical machine Ritchie's double plate machine, 548 The Tylerian machine, 549 Care and management of electrical machines Electricity from steam, 550 Other sources of electrical excitement, 551 Theory of the electrical machine Experimental illustrations of electrical attractions and repulsions The insulating stool, 552 Henly's electroscope Electrical bells Volta's hail-storm The electrical wheel By a candle flame, 653 V. Accumulated electricity and its effects Dis- guised or latent electricity The condenser of JEpinus, 554 The discharge of the condenser Volta's condensing electroscope, 556^Dr. Hare's single gold- leaf electrometer The Leyden jar, 557 Electricity in the Leyden jar resides on the glass, 558 The electric Jt>attery Discharge in cascade, 559 The uni- versal discharger The electric spark, 560 Kinnersley's thermometer The color of the electrical spark The electrical discharge in a vacuum, 561 Dif- ference between the positive and negative spark The diamond jar Scintil- lating tube and magic squares, 562 Effects of the electric discharge Physio- logical effects, 563 Inflammation of combustibles Chemical union effected

by electricity, 564 Volta's electrical lamp The mechanical effects of the electrical discharge, 565 The chemical effects Ozone VI. Atmospheric electricity Franklin's kite, 566 Free electricity in the atmosphere, 567.

I 3. Dynamical Electricity I. Galvanism and Voltaibm Discovery of galvanism, 568 The galvanic fluid Origin of Volta's discovery Contact theory, 569 Volta's pile, or the Voltaic battery, 570 Distinction between vultai^im and galvanism, 571 Quantity and intensity Simple voltaic couple, 572 Electro-positive and electro-negative Amalgamation, 573 II. Bat- teries WITH ONE FLUID Voltaio batteries Trough batteries Hare's calori- meter, 574 The dcflagrators of Dr. Hare Smee's battery, 575 The sulphate of copper battery III. Dry piles Dry piles of Zamboni and De Luc, 576 Boh- nenberger's electroscope IV. Batteries with two fluids Daniell's con- stantbattery, 577 Grove's nitric acid battery, 578 Carbon battery, 579 Other forms of voltaio battery V. Polarity, retarding power, and nomencla- ture OP THE VOLTAIC PILE Polarity of the compound circuit, 680 Grouping the elements of a pile Electrical retarding power of the battery Ohm's law, 581 FormulsD of electric piles, 582 Intensity given by many couples, 583 Effect of increasing the pumber of couples in a battery Effect of enlarging the plates of a battery, 584 Effect of enlarging the couples and increasing their number Faraday's nomenclature, 585 VI. The effects of the vol- taic PILE 1. Phyical effect* The voltaio spark and arch, 686 Regulators of the electric light, 587 Dubosq's photo-electric lantern Properties of the electric light, 588 Heat of the voltaic arch Deflagration, 689 Measurement of the heat of the voltaio current 2. Chemical effeett of the pile Historical, 690 Electrolysis cf water Voltameter, 691 Laws of electrolysis Electro- lysis of salts, 592 Electro-metallurgy The electrotype, 693 CrystalliiaUon from the action of feeble currents, 694 Examples Deposit of metallic ozydi and Nobili's rings, 595 3. Phyiological tffecu of the pile The physiological

ffecti of the roItAic pile ^Tbe magnatlc eiToete of th^ pi\& TIL Thcokt ot jmm Fit-m ^Thrwi vi^w*, oOA-'VDltii'g contact lhcf>rj', &f7 Tlie cbcmivaJ ibuoi'jr Ltrt 0f th diactigiLgvioeDt of electricity bjr cbemioal aciion Th ^ttUttJCj of electricity required if> produce cbemieal Mftiou, 598 Polar i&ntioti And trftQftfet- of tba eiemenU of a liqiiidChemieAl afliuiLj and molecular HUraction dtitiDgiiiubed Poecrhel'B moletiui^rr tboorj of iLb pili>, ^90-

I 4. lUectro Dynaaiioa I^ ELBCTRO^HAQiiEtt^H General U-^s, 00 CErited'i diJtcovery, OOl^Tbe dec trie taagoetio curroDt moves at rigbt anglei to the eoarj of the coitjaiictire wire (J alranom titers or muUiplicrt 64*2' The tangend or liiie eompaefl galvftnotaQter BbeoAtat, Mi Amp^rb'a elee|ft- iiUj^Deiie dlMOVeriet eiitl tbeory Mutual aetiou of ui^Qtrlo durreulai ti^lS Dli La RiTe*^ fioating: cunenC Hoget'ii oi|)OHii of fili^.'ii^us unimaloule* vf ex^'j^Iie f.c^i- I: -a :i;*.-**i.i--* w

form u conception itf the minute diinvE.*::E.* :: li-e** rx--: *=^--taie,

iirnl ^ot ?uch HCparute or^n of ererr ^r-lzLAlisI-r i? * ? !^;.cai cf

.-'xrral (>r;;unio 8uh.^tance!>. each in ia ziiTZ. c-icrn.'?::^ -c=::*n

atoinM of carlion, oxv/cu, and hjJro^en. I: i? i-lfcia fr.ci li-ese exinh

Il's that (he actual magnitude yf the nlui=e m:*.Til : *n j Wt

i^ Nometliiii^r completelj heyind the reach e^cAllT vf :r Kse* !*

rri>r, or of our intellects to comprehend.

:.'0. Atoms. Molecules. The ultimate i>>cni:ou:i c( m&ncr ha

liv idfMl th(> iipinion.H of philosophers fr-.-m the earl.'es* i*rt>i A

'I'v^o livpoihrHes have provaiIe;olids.

1 ^itxfQit** modiRciitioa uf Pvrkiii'fl ori^iDal appAimtiis Mrres to

demoatr&t the comprcAsibilUj qf Wfitf?r. A strong metaUio rw- m1. C, g. J; ia filled wUb wiitor, iLud i^lciai^d by a dote fitting crew plug, 13, fig. 3; unrj a perfectly p oUa bud cylindrical piflton of itool. A, pM^t-a wflter-tight Uirugfe th* steel collttr, P. When Uie tmaaI ] thus pruparcd, it ia plncud in a largi^r Tesfel eapaUe of mdaring grvmi pre4ure, which t^ oAa^ Alio J with water.

Proe^ure to ipj ext^tit deatrcd la then lippHcd by meau 3 of A hjiiraulin preia. It is eviduut that If tbe water wad&rgn&b diminution of volume whoiQ eubjcctod to pree- san^ tbe piatou A mast he forced into tha c^'linder to a corresponding extent. The Index T lif^viog hoen plaeed at a| of tb scale 5, if it if fi^und, o^^ter tbe experiment^ above tbftt poitti, M in g. 2;, it ia evidence of a corresponding deseent of the pi ate a, due to com press jcn of the water oontained in the cylinder C. Oc^ removing the pressure t|| tbe eUitirit^ of the water reatorr^ the orij^inal bulk. Water is footid, hy thb eiperiment, to yield about fifty millionth J of iti volume for Uftdh iitmoephere of pressure, i*^ e.j for a preifflore of CRoen pfmnda to a square inch.

In air and all gases we see tbe property of com- pre^tjibility very apparent. The air syringe is an instruuieut in which a portion of air Is compressed before a solid piston, with the evolution of so much heat as to set fire to tinder.

The return of gases and liquids to their original bulk on removal of the condensing force is due to a property termed daaticity, This quality exists in many solids, if not in all, and its consideration will be resumed hereafter.

22. Bxpanaibility. The expansion and contraction of all bodies by hmi and oold is a fact sufficiently familiar. Upon it is based the ffmainiction of all instruments for reading changes of temperature, for H^doscription of which the reader is referred to the chapter on heat.

23. Physical pores. The facts connected with the compressibility ef matter, and its change of form by heat, indicate clearly that

atoms of matter (assumed to be unchangeable) are not in contact. spaces existing between them are called physical pores, on the lence of which depends the property of porosity. Many chemical Bomena iUnstrate the existence of this property. If equal measure.*) tootbd mid water, or of water and sulphuric acid are mixed, th

12 PHirSICS OF SOLIDS AND FLUIDS.

bulk of the resulting liquid is sensibly less than the sum of the two liquids before they were mingled. This shrinkage can result only from the insinuation of the particles of one substance among the pores of the other.

The great amount of heat developed, during these experiments, is o significant fact. These molecular or physical pores of bodies are no more sensible to our organs than the atoms themselves, and are per- meable only to light, heat, and electricity.

24. Sensible pores. It is important to distinguish the molecular porosity just described from those sensible openings which give to cer- tain substances the property generally known as porosity. The pores of organic bodies, as of wood, skin, and tissues, are only capillary openings, or canals, for the passage of fluids. Nearly all animal and vegetable substances present these sensible pores. The familiar pneu- matic experiment the meratrial rain is an illustration of the porosity of wood. Many minerals and rocks are porous. Common chalk and clay are familiar examples. Hydrophane is a kind of agate, opaque when dry, but translucent when wet from absorption of water. Even gold, and other metals, under great pressure, as in the experiments of the Florentine academicians in 1661, are found to exude water.

25. Mobility. We constantly see bodies changing their place by motion, while others remain in a state of rest. The capacity of change of place, or of being set in motion, constitutes what is called mobility.

We recognize motion only by comparing the body moving with some other body at rest. If that rest is real then the motion is absolute, but if it is only apparent then the motion is only relative. Thus, on board ship, or on a rail car, the passenger appears to change his place in reference to objects about him. But all these objects are equally in motion with himself.

All motion on the earth's surface is relative, because the globe itself is impelled by a double movement of revolution on its own axis, and of translation about the sun.

Rest is also absolute or relative. Absolute when the body occupies really the same point in space relative when it preserves the same apparent distance from surrounding objects regarded as fixed, but which are not in reality so. A ship sailing six miles an hour against a current of the same velocity appears to persons on her deck to be advancing with reference to the surrounding waves ; but, viewed from the shore, or by comparison veith objects on shore, she appears at rest. Absolute rest is of course unknown on the earth, since every terrestrial object partakes of the double motion already noticed, and it is doubtful if any part of the universe is in absolute rest, seeing that the son

MOTION AND FORCE. 13

itself with the whole solar system is carried around with a rapid motion of translation in space about a central sun.

26. Inertia. No particle of matter possesses within itelf* the power of changing its existing state of motion or rest. Matter has no spontaneous power either of rest or motion, hut is equally susceptible to each, according as it may be acted on by an external cause. If a body b at rest, a force is necessary to put it in motion ; and conversely, it cannot change from motion to rest without the agency of some force. A body once pat in motion will continue that motion in an unchang- ing direction with unchanging velocity until its course is arrested )>y external causes. This passive property of matter is called inertia, Descartes first gave definite expression to this law in his *' Principles.''

When we are told that a body at rest will for ever remain so, unless it roccivcs an impulse from some external power, the mind at once assents to a statement which embodies the results of our constant experience. But it requires some reflection in one who for the first time considers the subject, to admit tli;it Ix'dicii in motion will continue to move for over, unless arrested by cxttrual forces. C.'u-i>cll.ation defined. 78.

Oamoiw. 244 ; onnditiona of; 240.

'tomuMf of luorffaoic MluUons, 240; of organic

ai>lttilonK, 248; dlrectiOD of current, 247. Overahot vheel, 220. Oaooe, 860.

Page's revoWlnK magnet, 014.

l\iffe't Tilirating armatare, 031.

Jaracliute, 273.

rarlMlia, 637.

Parallel forcM, reiultant of, 40.

ParalleloKram of fbroeo, 46; of rotationa, 60; of elodtlea. 34.

I\ueart expath8of vibration. 311.

PencilH of liglit, 401 ; refiracted at plana snr- fttcea, 443 ; at iiph*rlcal nurfacea, 440.

Pendulum, 78; applied to meamire time. 84; applied to ntuily of Kravlty, 87 ; ballistic, 1U4; eouipeniiating. &U6; cydoidal, 85; de- mouKtraltM rotation of the earth, 86; formn- In f*r. 81; iiw>i-hronim of. 80; length beat- ing Kecondft, 89; pliyMcai or compound, 83; prtfpoflitiona revpectin;:, 82; simple, 79; used to measure force of gravity, 88.

Penetrating power of microaoopet, 513; of teiearopeii, 507.

Penumbra, 411.

Percufsion a M)urre of heat, 740.

iVrffct ronrtrd, 372.

I\rk-inf' appnrHtUR, 731.

IVrpetual motion. 135.

Pha.ei of undulationa, 304.

Phenomena defined, 2; of expansion, 594.

PhiloRophii-al egg. 852.

PhoHphore^rence, 399, 534.

Photo eli^ctric lantern, 884.

Photography, 619.

I'hotometeni, 414.

Physical force. 6; porea, 28; optica, 527; soun'CH of heat, 742; tablet, page MO; theory of music, 363.

PhyKicH and chemistry, 9.

Physiological eff^Mots of the pile, 805.

Piano strings friable, 180.

Plnne glass, refraction by, 441.

Plants, electricity of. 945.

Plateau' $ experiment, 200.

PlHtcs. vibration of. 312.

PIntform bnlnnce. 116.

Pneumatic ink-bottle, 2S4.

Pneumatics, 262.

Polarity of compound Hrenit, 878.

PolarizHtion and transfer of elementj, 800.

l*olarization, atmofipheric, 561 ; by absorption, 645: by heat and by compreaaion, 660: by reflection, 646; by refraction, 547, 548; coloreil. 566; of heat, 640; *of light, 641; parUal, 540; roUry, 550.

Polarixlnf mitniD^nli, 664.

AwVt moiieal foala, VZ.

Poraa, pliyflcal, 23; MBiibla, 9^

Porosity, 28.

Positive and negative cryeUla, 661.

Poeitive ^e-pieoe. 500.

PamlkVi galvanometer. 00&

Power of points, electrical, 830L

Power of steam, 714.

l*ower, adaptation to weight, 110.

Power and weight, 106; relation ot, lOOl

i'reaa, hydrueUtic. 100.

t^reaanre, atmosphmrie, 267 ; centre oC 197 : ol liquid in motion. 226; of liquid downward, 191; of Uquid on side of veaaei, 103; of liquid upon containing veaeel, 214: prodnoad by impact, 112; transmitted by gaaea, 2U; tranamitted by liquids, 180; varies with Sp. Gr., 198.

Primary colors, 4dA.

Prime seventh. 873.

/Vmoe BuperfM drops, 178.

Printing telegraph, 025.

l^risms and lenses, 438.

Problems on acoustics, pagtt 288; on dasttdty and tenacity of solids, pace 146; on dsfr- tridty page 667 ; on gravitation, page 73; on heat page 506; on hydrodynamics, pa^ 190; on laws of vibrations, pa^ 261; on throrrct machinery, page 107 : on optics, page SOS; on pneumaticK. page 234 ; on weights, msa- sures, and motion. |iage 37.

Production of waves. 319.

Products of combustion and respiration, 718.

Progreosive undulationa. 3U0; in liquids. 320.

Pro|)erties of matter, general or rpecifie, 6; phy^ical or chemical. 8.

IVopertiea of liquid and solid gases, 601; of solar spectrum, 460 ; of solids, 140.

Propositions in regard to forces, 42.

Pn>je< tiles, theory and laws of, 103

Proof plane, 823.

Pulley, compound, 120; fixed, 118; movable 119.

Pumps, 280-293.

Pyrometers, 689.

Pyrometer, DanielPs. 584; Draper's. 565; Sa ton's reflecting, 582; Wedgewood's, 583.

Pyrometrlcal heating effects, 762.

QuALiTT of musical sounds, 363. Quantity and intensity of electricity, 866. Quantity of heat from friction, 730.

Rain. 980 ; snnual depth oi; 983 ; days oi; 982;

distribution of, 981. Radiant heat, intensity of, 631 ; partially sL

sorbed, 630; transmission of, 041. Radiating power for heat 638. Radiation, of cold. 634 : of heat, nnlvenal, 6B,

Uw of cooling by, 632; terrestrial, T4k Radiators, steam, 782. Railway illnmination, 520. Rainbow. 636.

Ramsden't electrical machine, 836 Range of human voice, 390. *

Raya of light, 401. Reaction of escaping liquids. 217. Jieaumur*$ thermometer, 570. Recompoaition of while light 467. Reed pipes, 381. Regulators of etoetrie light, 884

INDEX.

707

Reflecting teleteope. 601.

ReUectioii *t carved Hurfares. 426: by plane

mirrorff, 418; by regular Murfiiceii, 415; of

rlrrular waves. 326; ot light, 4W; of sound.

:i5'2: of wRveI. 8uiTa. App. tab. IX. Ab.orptlve power of different t)0die8. App. tab. VIII. " Aqui-oufl vnpor In a cubic foot of snto-

rated Mir at different tcmperaturets I " App. tnb. XXI.

" Barometric column at yarloos altl- !

u J";'*:^:^.\ Teie^im,

INDEX.

709

Tenacity of dllfennt anbataaeai, 170.

Teiiarlty, lawi of; 170.

TeDHioii, 2o:2; chnniCM dannlty. 160; maximam. of va^HtrN, 60tf ; of vapors. Ualton't law. 070 ; of viipi>ns in rammuiileaUDg Tcmelii. 071.

Terivntrial attrartioa, diraetion oi; 60; point ofMpplifatiuu. 61.

Tenvfiriiil eyv-pieoa. 500 ; bnat. origin of^ 746; ir.a;(nt*tiaai, 7b7 ; radiation, 7ruin of Archiinodefl, 205; of Tbrrloalli, 210.

TheoreCiral and actual flow, 2l6i

TborltMi of endosmoM. 251 ; of light, 308; of li^ht unnatinractory, 406.

Tlieitry dtfAned. 3; of liquefiMstion and aolidifl- cation ofgNiMfa. 688; of andnlatloni^ 2U9.

TbernnJchnMy, 646.

Tlieriiio-tlvctricity. 041.

Thermo electric motionH, 041.

Theriuoniitfn, 667 ; air. 6M7 : Bregnat** metal> lie. 6H0; CBiiU;aiidtN 670: oompariann of raVii of, 571 : con ntr action of, 668: dfrd*8 mnximuin and niinimum, 678; &ixU>n't d'Hf, M'a, 581; M*lf r|ci>*t^rinK. 678; wuni* Mllty of. 572: spirit 675; Ktandard, 577; t^t! of. 572; Waifenlln'H maklmuniy 678.

TliHrinomi'iric ial:{: rhani^i'd by echo, 866.

Tornnd fK. 060.

TorriivUian th>orrm, 210; damonatratad, 220.

Torrl'-fllian vncuiim. 201.

Tominn. flaKtlHly of, 166; vlfrtromatar, 820; l.twH of. iwi: of riidd burs. 167.

T itHl hvilrootiitic prKMum 100.

ToiNl reflection. 4U0.

Triiliii of wlietfilwork. 117.

Tiaii'ipo^liion in muvlc- 37i.

Tniiinvemtt ulrength. 172.

TuIm-i*. Ktreiiictli of. 172,

TiiliuUr bridjceo, 172.

Tuiilnsc fork. :{77.

Turbine wbeol. 231.

Ttpfm'nff't U-v niarhlne, 681.

TvleHnn eltfctriral machine, 837.

Tympanum, 393.

I'MRK^, 411.

l-iidiTxhot whel, 230.

UiiiiiiUiion in ocean*. Ac, 330; of elaatle ItnMo. XW: nf ItqnldH. 319.

UndulHiioiiH of a ftpberH of air, 331 : of aolidis ;t4Mt; origin of, 2^^.*: phib-e'* of. 304; prognii- hivH. .3tHi; proKrwftHive, in liquids, 320; sta- tionary. 3ri.

(iniform motion. 3().

Uniform nm-iral pitch, paga 066.

Uniin, 364.

Unit of force, 37.

62* 8

I Units of maaaura, 1&

Universal diaihargar. 861 ; graritation, Uv o( I 59; radiation of beat, b33.

Uoiitbbie etiuilibrium, 21)7. . Upward prenaure of liquida, 102.

Vacuum, Torricellian, 261; vapon formed in,

668. Value of fbel, 716.

Value nfg In pendnlam experiments, 80. Vaporization, 6o7.

Vaporisation, tomperatara, and limits, 672. Vapora, 2iV2: and gaavs, identity of, 688;

density of, 603; formed in a vacuum, 668;

from the body, 710; Latonr's law, 602;

liqoefiiction of, 686; maximam tension, 6b0. Variable motion. 31. Variatiou chart. 780. Variations of iMrnmetrie height, 270; of mag'

netic needle, 7NH; annual, daily, 700. Vegetablea, teuipemture uf. 767. VeiiM-itiea, actual and theoretical, 144; par*

allelograui of. 34. Velocity after Imfiact. 184; of all aounda the

same, 34;.*: of all Houudii not the same. tge

tjMi of aerial wavea, 332; of electricity,

bl8: of light. 4o4; of rivers and strtsams,

227; ofM>iindiualr,344;ofsoniidin liquids,

347 ; in a(lidM, 348 ; of sound, Newtou^s for- mula. 663. Ventilntion. 7 16-726; aprartiral problem. 722;

uve^*lly oC 718; quantity of air required,

7au. VentiUting shaft, 723. VKutilnlora. 725. VentriiiMiuifnT, 391.

Verification of laws of foiling bodies, 72. Vernier, 266. Vibmiing armature. 031. Vibrating daniH, 386. Vibration of air in tubes. 870, 384; of cords,

3UH; laws of. of cordK. 3U0; of rods, 310;

of membrane*. 318; of plates, 312; of plataa^

lawM of. 315: palhx ot, 311. ; VIbrationis 299: form* of, 307; from magnai> I ii*m.OI6: iMM-hronous,3u3, of different nutea, , sbHolute. 360: relative. 3i.K; of heat and

light, 7G5 : of light, direction. 541 ; of light, < length of 531 ; ot liglit. tranHmission of, 642; I '^ lighU resolution uf, M4. Vki .ria tubular briilge. 172. Mrtualfiicuif. 429: imagia,434; velocities. 106. > Visible bi-dies 4u2. ViHifiD. 44iH ; iHmditiona of, 476 ; binocular, 484;

double. 48:i; single, 482. Visual anjzle. 472.

Visual impree>ii*ns roqa.*re time, 4X0. Vlaual power of microscope, 613 ; of telaaoopea,

6t7. ViKual rays nearly parallel, 470. Via viva. 111. Vitality. 10.

Vocal api>aratua of man, 388. Voice and cpeech. 387. Voice, mechaniam of; 380; range of human,

390. Volta-electrlc induction. 020. VnlUle art- h. heat of 886. Voltaic tiatteriea, 860-881 ; effects In Tsriouf

forma. 881. Voltaic cirruit, polarity of, 878. Voltaie couple. 866. Toltato curfanta, baat ot, 887. A

710

INDSX.

Toltaie 6letricity, qoaotity and Intensity, 8flA.

T(dUle pile or battury. 8b4: clieinil theory, MS; ffToupInK f>li*inf>ntf>, 879; phrnieal i4- frets. 883: phvkloKieal effrcts, 86; toM^ nsUe rffi^tn, 806; tbaonr of, 890.

Toltiiifl npiirk and nrch. 888.

Tollabm and galTanliiin, 804.

Vi4kC$ onntaet theorj. 808. 807.

FU