Imágenes de páginas

Tudor Specimen of Kozoon, J. W. Gregory, 486

Turner (F.), the Acclimatization of the Avocado Pear in New

South Wales, 66
Turner (H. H.), Solar Disturbances of 1891, June 17, 404
Turner (Sir W.), the Lesser Rorqual Whale, 454
Tutton (A. E.): Iron Carbonyl from Water Gas, 36; Further
Researches upon Azoimide, NSH, 127; Phosphorous Oxide,
ii., 214; Phosphorous Oxide, 446; the Properties of Amor-
phous Boron, 522
Tylor (Dr. E. B.): the Limits of Savage Religion, 71 ; the

Bow as Origin of Stringed Instruments, 184
Tyndall (John, F.R.S.), New Fragments, 508
Typological Museums, General Pitt-Rivers, 184
Tyrell (T. B.), Geology of Lake Winnipeg, 115

Ungulates of South America, Aberrant Fossil, 608

Umney (J. C.)t the Aconite Alkaloids, ii., 525

United States: Weather Bureau of the, 86; Education in,
156; Production of Pig-iron in, John Birkinbine, 208;
the Paper-making Industry in the, J. F. Hobart, 279; U.S.
Naval Observatory, Report of, 352 ; the Mountain Meteoro-
logical Stations of the United States, A. L. Rotch, 403;
the Study of Psychology as a Science in the United States,
E. W. Scripture, 568

Units, C.G.S. System of, O. H. Tittmann, 581 ; Prof. J. D.
Everett, F.R.S., 581

Universal Atlas, the, 52

Universities in Australia, Prof. Morris on, 426

Universities, Functions of, Prof. Geo. Fras. Fitzgerald, F.R.S.,

University College, London, Proposed Extension of Physical

and Engineering Departments, 348
University Colleges in Great Britain, Report of Committee on

Grants to, 544
University Extension Movement, Lord Cranbrook and the,


University, the Function of a, Prof. W. E. Ayrton, F.R.S.,

University Intelligence, 23, 45, 70, 92, 118, 139, 162, 286,

334. 356, 381, 428! 449. 549, 622.
University of London, W. T. Thiselton Dyer, F.R.S., 392;

Prof. E. Ray Lankester, F.R.S., 413; Prof. W. F. R.

Weldon, F.R.S., 440
University, the Proposed Gresham, 323, 443, 517
University, Teaching, for London, Royal Commission to inves-
tigate the Question of a, 612
Upham (Warren), Fossils recently Discovered near Boston,

Uraninite, New Analyses of, W. F. Hillebrand, 119
Uranium in Swedish Anthracitic Minerals, Discovery of, Baron

Nordenskidld, 209
Urinary Secretion of Nitrogen, Dr. Gumlich on the, 599
Urine in some Infectious Maladies, Ptomaines extracted from,

A. B. Griffiths, 72
Useless Studies, Value of, Prof. Geo. Fras. Fitzgerald, F.R.S.,

Utilization of Homing Pigeons, W. B. Tegetmeier, 320

Vaccination of the Dog, the Tubercular, Hericourt and Richet,

\ acher (M.), Workmen Killed and Wounded in Accidents in

Germany, 350
Vacuum Discharge Streamers, on the Action of, upon each

other, Dr. M. I. Pupin, 622
Vacuum Tubes and Electric Oscillations, Prof. Oliver I

Lodge, F.R.S., 366
Valence of a Coloured Radiation, Hering, 115
Value of Useless Studies, Prof. Geo. Fras. Fitzgerald, F.R.S.,

Value, an Introduction to the Theory of, William Smart.

Varet (Raoul), Action of Metals on Salts Dissolved in Organic

Liquids, 360
Variability of Nebulae, Dr. Lewis Swift, 522
Variable Nebula;, Some Apparently, Lewis Swift, 261
Variable Stars, Fuzziness of Some, Cuthbert G. Peek, 497
Variables, Two New, in Cepheus, Paul S. Yendall, 570
V ariation of Latitude, Dr. S. C. Chandler, 404, 589; Robert

B. Hayward, F.R.S., 465; Dr. B. A. Gould, 321 ; on the,
M. Faye, 570

Vasey (Dr. George), Grasses of the South-West, 390

Vaussenat (C. X.), Death and Obituary Notice of, 207

Vedalia cardinalis successfully Colonized at the Cape of Good
Hope, 615

Vedel (Lieut.), on the Polynesians, 615 -"

Veeder (Dr. M. A.): Auroras at Lyons, N.Y., 7 ; Red Light
after Sunset, 30; Plan for Observations to Determine Local
Distribution and Altitude of, 234; Magnetic Storms, 557

Velocity, Molecular, Relation of Voltaic Electromotive Force to,
Dr. G. Gore, F.RS., 596

Venus, Rotation of, Herr Loschardt, 210

Verbeek (Dr. R. D. M.), Relics of the Hindu Period in Java,

Vereker (Hon. J. G. P.), the Resolution of Podura, 239

Verner (W.), Threatened Extermination of the Kentish Plover,

Vesuvius, Eruption of, 259

Vibrations, on Earth, Dr. Emil Oddone, 510

Victoria: Victoria Agricultural Department, Results of the
Travelling Dairy, A. Crawford, 39; Hand-book of the De-
structive Insects of Victoria, C. French, 246; Experimental
Perfume Farming in, 305; Viticulture for Victoria, F. de
Castella, 324

Vienna, Annates of the University Observatory in, 138

Vienna, a New Epidemic in, 349

Vilmorin (Philippe L. de), Les Fleurs a Paris; Culture et
Commerce, 510

Vincent (M.), Thermometer-Temperature and Skin-Tempe-
rature, 304

Violle (J.), Radiation of Incandescent Bodies and Optical
Measure of High Temperatures, 552

Virial Equation for Gases and Vapours, on the, Prof. P. G.
Tait, 199

Virial of a System of Hard Colliding Bodies, on the, Lord
Rayleigh, F.R.S., 80

Vision, Peculiar Eyes, James Shaw, 104

Viticulture: the Wines of the Medoc District, 279

Viticulture for Victoria, F. de Castella, 324

Vogel (Dr. E.), Praktisches Taschenbucli der Photographie, 51

Vogel (Prof. H. C.): Motion of Stars in the Line o'f Sight,
280; the New Star in Auriga, 498

Volcanoes: Projected Abandonment of Villages near Colima
(Mexico), in Consequence of Activity of Neighbouring Vol-
cano, 158 ; Volcanic Action in the British Isles, Sir Archi-
bald Geikie, F. R. S., 398; Volcanic Action in Eastern
Australia and Tasmania, T. W. E. David, 424; Eruption of
Vesuvius, 259; Discovery of Saltpetre and Soda in Kilima-
Njaro District, 379

Voltaic Electromotive Force, Relation of, to Molecular Velo-
city, Dr. G. Gore, F.R.S., 596

Vonberg (Prof. Ignace), 518

"W = Mg," Prof. Arthur G. Webster, 29

Waals's (Van der) Generalizations regarding " Corresponding"

Temperatures, Pressures and Volumes, Prof. Sydney Young,

Waals's (Van der) Isothermal Equation, Prof. D. T. Korteweg

on, 152, 277
Wagner (Rudolf von), Manual of Chemical Technology,

Walker (Alfred O.), Destruction of Immature Sea-fish, 176
Walker (G. T.), Repulsion and Rotation produced by Alternat

ing Electric Currents, 213
Walker (J. J.), Ants' Nest Beetles, 351
Wallace (Dr. Alfred R.) : Topical Selection and Mimicry, 30;

the Naturalist in La Plata, W. H. Hudson, 553
Waller (Augustus D.), an Introduction to Human Physiology,

Dr. E. H. Starling, 340
Ward (Prof. H. Marshall, F.R.S.): the Ginger-beer Plant, 190;

The Oak, a Popular Introduclion to Forest Botany, 509
Warner Observatory, 422
Warning Colours, Frank E. Beddard, 78; Edward B. Poulton,

F.R.S., 174; W. L. Distant, 174
Washington Observations, 1886, 237
Washington Observations, 1887, 548
Washington Weather Bureau, Atlas issued by, 587
Washington, Wind-rush at, Prof. H. A. Hazen, 597

Water, an Elementary Hand-book on Potable, Floyd Davis,

Prof. Percy F. Frankland, F.R.S., 25
Water, Air and, Vivian B. Lewes, 531
Water Gas, Iron Carbonyl from, A. E. Tutton, 36
Water Jets, Sensitive, W. B. Croft, 606
Water-supply of London, John Ilopkinson, 88; Appointment

of Commission on, 470
Watson (Rev. H. W., F.R.S.), on the Boltzmann-Maxwell

Law of Partition of Kinetic Energy, 512
Watson (Sereno), Obituary Notice of, 494
Watson (W.), Effect of Fog on Plants Grown in the Houses at

Kew, 16
Wave-motion Model, F. Cheshire, 347
Waves, Remarkable Illustration of Height of Breaking, 305
Weather-cock, Self-Registering, J. Lawrence-Hamilton, 559
Weaving as practised by the Navajo Indians, Dr. Shufeldt,

Weber (Prof. Max), Freshwater Fauna of Sumatra, Java, 4c,

Webster (Prof. Arthur G.), "W = Mg," 29
Weight, Examination of the Standards of Measure and, im-
mured in the Houses of Parliament, 543
Weinschenk (E.), Meteoric Iron, 69
Weismannism, a Difficulty in, Edward B. Poulton, F. R.S.,

52; Prof. Marcus Hartog, 102; A. H. Trow, 102, 175
Weiss (F. E.), Caoutchouc-containing Cells of Eucommia

ulmoiJes, 335
WeMon (\V. F. R.), the Renal Organs of certain Decapod

Crustacea, 140
Weldon (Prof. W. F. R., F.R.S.), the University of London,

Wells (H. L.), a Series of Cesium Trihalides, 310
Wells and Penfield (Messrs.), Remarkable Series of Compounds

of Halogen Salts of Ccesium with Two or more Atoms of

Chlorine, Bromine, or Iodine, 325
Werigo's (Dr.) Experiments respecting Influence of Oxygen on

Elimination of Carbon Dioxide of Lungs, Prof. Zuntz, 576
Wernadsky (W.), the Sillimanite Group and the Part played by

Aluminium in the Silicates, 141
Wesendonck (Prof.), Gaseous Carbonic Acifl not capable of

Generating Electricity by Mechanical Friction on Metal, 306
West India Islands, Zoology and Botany of the, 139
West Indies, Dr. J. T. Rothrock on the Flora &c. of the

Bahamas and Jamaica, 596
Westgate on-Sea, Aurora Visible from, 613
Wethered (Edward), on the Microscopic Structure and Residues

Insoluble in Hydrochloric Acid in the Devonian Limestone of

South Devon, 597
Weyl (Dr. Th.), Animals rendered Immune to Anthrax, 312
Whale, a Steamer's Encounter with a, 88
Whale, the Lesser Rorqual, Sir W. Turner, 454
Wheat, Rust Fungus in, 615
Wheat in Ohio, the Average Yield of, geologically considered,

Whipple (G. M.). Magnetic Disturbance, 364
Whitaker's Almanack for 1892, 156

Whitcombe (Rev. R. H.), Elementary Trigonometry, 174
White (W. H., F.R.S.), the Influence of Shallow Water upon

the Trial Trip Speeds of Modern Vessels, 571
White (William), Darwinian Theory, 53
Whiteley (R. Lloyd), Chemical Calculations, 604
Whitney (W. Dwight), the Century Dictionary, 316
Whymper (Edward): how to Use the Aneroid Barometer, 339;

Travels among the Great Andes of the Equator, Prof. T. G.

Konney, F.R.S., 561
Wiborgh's (Prof.) Air-Pyrometer, Tohn Crum, 304
Wild (H), the Magnetic Storms of February 13-14, 1892, 4S0
Wilkins (A.), Intelligence in Birds, 151
Wilks (W.), the Place of Horticulture in Technical Education,

Willey (Arthur), a new Genus of Synascidians from Japan, 450

Williams (Dr. C. Theodore), Value of Meteorological Instru-
ments in Selection of Health Resorts, 551

Williams (F. N.), the Genus Dianthus, 383

Williams (Prof. G. H.): a Geological Excursion in Maryland,
235; the part played in Growth of Geological Opinion by
Regions near great Universities, 519

Williams (J. Francon) and William Hughes, the Advanced
Class-Book of Modern Geography, 460

Willis (J. C), the Method of Fertilization in Ixora, 455

Wilson (F. R. L.), Action of Dry Hydrochloric Acid Gas on

Dry Carbonates, 503
Wilson (Prof.), Experiment Illustrating Power of Palladium of

Occluding Hydrogen, 380
Winchester, Macro-Lepidoptera and Birds of, 115
Wines of the Medoc District, the, 279
Wing in Din^rnis, Evidence of a, Henry O. Forbes, 257
Wind Direction, 149

Wind-rush at Washington, Prof. H. A. Hazen, 594
Winnecke's Comet, Dr. G. F. Haerdtl, 617
Winnipeg, Lake, Geology of, J. B. Tyrell, 115
Winter Storms of Northern India, Henry F. Blanford, F.R.S.,

Wislicenus (Herr Dr. Walter), on the Influence of Ring and

Disk Blinds in Micrometic Measurements, 137
Wissmann (Hermann von), My Second Journey through

Equatorial Africa, 507
Within an Hour of London Town, 557
Woeikof (Dr. A.), Cold Waves, 357
Wolf (Rodolf), Solar Activity in, 1891, 307
Wolfs Periodic Comet, 42; Dr. Berberich, 237
Wolf's Comet, 1891, 11 ; Herr Dr. Thraen, 548
Wolf's Numbers for 1891, 307
Wolstenholme (Prof. Joseph), Death of, 85
Wood (Sir H. Trueman), Light, 269
Woods, Furniture, D. Deeming, 459

Woodward (Mr. A. S.), Appointed Assistant Keeper of Depart-
ment of Geology at British Museum, 566
Woodward (M. F.), the Milk Dentition of Procavia (Hyrax)

cafensis, 287 ; Teeth Development in the Marsupialia, 333
Worship, Dwarfs and Dwarf, Harold Crichton-Browne, 269
Worthington (A. M.), the Mechanical Stretching of Liquids,


Wray (Leonard, Jun.), the Ipoh Poison of the Malay Penin-
sula, 278

Wright (C. R. Alder, F.R.S.), on Certain Ternary Alloys, v.,


Wright (Prof. G. Frederick): the Theory of an Interglacial Sub-
mergence in England, 310; Cirques, 317

Wrightson (J.), Farm Crops, 247

Yahgan, the, P. Hyades and J. Deniker, 577

Yarrow (A. S.), on Balancing Marine Engines and the Vibration
of Vessels, 571

Year, the Origin of the, J. Norman Lockyer, F.R.S., 487

Year-book of Science, 1891, Prof. T. G. Bonney, F.R.S., 604

Yeast, Milk Ferment Identical with Kefyr, in use in Canada and
United States, C. L. Mix, 471

Yellow Butterflies, Pigment in, F. Gowland Hopkins, 197

Yendall (Paul S.), Two New Variables in Cepheus, 570

Yezo, the Fauna of, Dr. Adolf Fritz, 89

Young (Prof. C. A.): Note on the Chromosphere Spectrum, 28;
the Chromosphere Line \ 6676-9, 198

Young (Prof. Sydney), Van dcr Waals's Generalizations regard-
ing " Corresponding " Temperatures, Pressures, and Volumes,


Younghusband (Capt.), Journeys in the Pamirs and Adjacent

Countries, 353

Zebra, on the Attitudes of the, during Sleep, and their Influence
on the Protective Value of its Stripes, 248

Zebra, Skin of Grevy's, brought from Somaliland, 598

Zebras, Notes on, S. B. Carlill, 526

Zeitschrift fiir Anorganische Chemie, 421

Zeitschrift fiir Pflanzenkrankheiten, 20

Zimbabwe Ruins, Finds at the Great, Theodore Bent, 551

Zodiacal Light, O. T. Sherman, 381

Zoology: Zoological Gardens, Additions to, 21, 41, 67, 89,
116, 137, 159, 186, 210, 236, 260, 280, 307, 325, 351, 380,
404, 422, 445, 472, 497, 521, 547, 569, 589, 616; the Death
of the Giraffe, 518; Zoological Society, 70, 164, 287,
3S3, 430, 503, 526, 597; Enormous American Lizard,
L. Steineger, 40; Herr Lehmann on the Camel, 87;
Prof. Cossar Ewart on Scottish Zoology, 87; Zoological
Regions, G. A. Boulenger, 104; Dr. Stirling's New Aus-
tralian Animal (Notoryctes lyphlops), J. D. Ogilby, 135;
Squirrels in Winter, C. Fitzgerald, 136; Zoology and Botany
of the West India Islands, 139; Text-book of Comparative

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Anatomy, Arnold Lang, 145; Lehrbuch der Vergleichenden Entwickelungsgeschichte der Wirbellosen Thiere, Dr. E. Korschelt und Dr. K. Helder, 145; the Migration of the Lemming, F. Howard Collins, 149; W. Duppa Crotch, 194, 294; Prof. George ]. Romanes, F.R.S., 249; W. Mattieu-Williams, 294; Big Game in India, Harold Littledale, 158 ; Discovery of New Species of Frog in New jersey, Prof. E. D. Cope, 208; Animal»Sketches, C. Lloyd Morgan, 291 ; Animals recently Extinct or Threatened with Exterrnination, F. A. Lucas, 305; Freshwater Springs in the Buffalo Bay and Niqara Region, Dr. Kellicott, 305 ; Zoology of the Sandwich Islands, Mr. R. C. L. Perkins Selected to Investigate the, 322; the Hydrocorallinae Collected by Pro£


_/mic 2, 1892.

Haddon in Torres Straits, S. _I. Ilickson, 407; Freshwater Fauna of Sumatra, Java, &c., Pro£ Max Weber, 408; the Puma, P. \V. True, 445 ; the Lesser Rorqual \Vhale, Sir \V. Tumer, 454; Zoological Record for 1890, 483 ; n. Zoologist on Disease, Dr, Elie Melschnikoff, Prof. E. Ray Lankester, F. R.S., 505; Mr. Charles Hose’s Collections, 517 ; Notes on Zebras, S. B. Carlill, 526 ;a New Oryx (073/x ral/alis), 526 ; the New Imperial German Zoological Station at Heligoland, 544 ; Egg of the Extinct Gigantic Bird of Madagascar /Lrg]/0f71l'J maximur, 586

Zune (M.), the Composition of Haemocyanin, 456
Zuntz (Prof.), Dr. Werigo’s Experiments respecting Influence

of Oxygen on Elimination of Carbon Dioxide by Lungs, 576

[graphic][merged small][merged small][merged small]



Electricity and Magnetism. Translated from the French of Ame'de'e Guillemin. Revised and Edited by Silvanus P. Thompson, D.Sc, F.R.S. (London: Macmillan and Co., 1891.)

THIS work is an English translation of M. Ame'de'e Guillemin's popular treatise of electricity. We are informed, in the preface, that the translation has been in great part executed by Mr. Colman C. Starling and Prof. Walmsley, under the editorship of Dr. Silvanus P. Thompson. It is a splendidly illustrated and beautifully got-up book, designed, so the editor says, rather for the table of the drawing-room than for the desk of the student.

We doubt whether, in fashionable drawing-rooms at any rate, scientific curiosity exists to any great extent; but now that large houses are very frequently lighted with electricity there may be a minority of people who are willing to spend any spare time left over from more absorbing drawing-room occupations in learning something of how the light is produced and of other applications of electricity. For such a public the present work seems exceedingly well adapted. It is popularly and attractively written, so far as a translation from a foreign tongue, supplemented, and to some extent corrected, by editorial paragraphs, can well be; it is profusely illustrated, and comprehensive to an extent which has made the book almost too bulky for convenient perusal.

Still, the remnant of people by whom popular scientific treatises such as this are welcomed, though numerous in itself, is, alas, only a very small minority of that great and influential section of the British public who are brought directly into contact every hour of their lives with the wonderful practical results of the progress of science. The great majority converse through telephones, consult their watches, and send telegrams, and know no more than a Hottentot does how a telephone acts, a watch goes, or a telegraph message is transmitted.

The book is divided into two parts, dealing respectively with phenomena and their laws, and practical applications; or, speaking briefly, theory and practice. In the theoretical part, magnetism is first treated, then electricity, in the order statical electricity, electro-chemistry, and electro-magnetism. In the practical part are comprised telegraphy and telephony, electric lighting and transmission of power, and a number of minor, but in themselves important, applications, such as clockwork-driving and regulation, electricity in warfare, and electroplating. Of the treatment of these subjects we can give here only the merest sketch, noting as we do so a few points in which the book seems to call for modification or improvement in a new edition.

The theoretical part begins with a brief account of the natural history of magnetism, then passes to a discussion of the polar theory of magnetism, starting with the notion of Thales that a magnet had a soul, and ending with the experiments of Coulomb and their results. An excellent description of Coulomb's torsion-balance experiments is given, and then follow the methods devised by Coulomb and Jamin for the determination of the distribution of magnetism in magnets. It is hardly correct to say, as is done on p. 33, that Coulomb's method "enabled him to study the distribution of magnetism in magnets; that is to say, how the magnetism at the surface varies along the magnet between one end and the other." Apart from the objection that the field at any point external to the surface of the bar depends really upon the whole distribution of magnetism, and not merely on that supposed to be near the point, and the further objection (which also does not seem to be stated here) that the vibrating needle itself affects the magnetization of the mignet, it is quite certain that this method, like others devised for the same purpose, cannot be made to give any definite information except as to the surface-distribution of magnetism, which, as Gauss showed, can be made to replace the magnet so far as the external field is concerned. By none of these methods can any information whatever be obtained as to the actual magnetization of a bar of finite cross-section.

It would have been well also if the editor had here appended a note as to the essential inaccuracy of Jamin's method " of placing on the point that we wish to study a small contact-piece of soft iron, and of measuring by means of a graduated spring that gradually extended, the force requisite to detach the iron," and given a description of the much more satisfactory method adopted by Rowland and others.

After a chapter on methods of magnetization, in which all the ancient and now discarded methods of "touch" are described, we have an excellent popular discussion of terrestrial magnetism, ending with a splendidly illustrated account of aurora. The introduction of the subject of aurorae at this point is justified on the ground that they are electrical phenomena connected with the magnetism of the earth, and a sketch is given of the various theories which have been proposed.

Passing now to the subject of electricity, we have the same wealth of illustration, though many of the smaller cuts, like some of those in the section on magnetism, are old familiar friends. Electrical machines are described, from Otto Guericke's down to Wimshurst's. Nothing impresses us as more indicative of the enormous advance of electrical science in recent times than a comparison of Plates V. and XIII. of this book. The former, a well-known picture, represents an electrical machine "according to the model in fashion about 1754."; the latter, a large Edison steam-dynamo. In the former a bevy of ladies and gentlemen in the costume of last century are grouped round a sulphur ball machine, which a gentleman in powdered wig and ruffles is vigorously turning by means of a crank attached to a large and much ornamented driving-wheel of wood. Evidently we have here "electricity in the drawing-room," as practised in the middle of last century. On the other plate we see a large modern steam-engine, in all its array of steam-pipes, balanced cranks, and connecting-rods, resting on a massive bed-plate of iron bolted to a base of masonry, and driving an enormous dynamo. The somewhat dilettante group of men and women have disappeared, and in their place stands a typical Yankee engineer, oil-can in hand, and coatless, intently regarding the bearings of the engine. Here there is no unnecessary ornamentation, no suggestion of elegant trifling, everything is sternly suggestive of work and nothing else. Nevertheless, in the contrast, the real dignity and beauty is with the present, not with the past; with modern science in the laboratory, the workshop, or the factory; with work carried on in the deepest earnest, with plain duty-doing, irrespective of sensation or applause.

Next comes an account of batteries, which (like several other parts of the book) we think might very well have been lightened by ignoring old and obsolete pieces of apparatus ; after that, we have a discussion of the production of electric currents. In a book of this size, in which a considerable amount of space is devoted to things relatively unimportant, the subject of electrolysis might have been more fully treated; for example, there are matters connected with electrolytic theories to which, since such a theory as that of Clausius is introduced, a few pages might very well have been devoted. The absolute measurement of currents by means of electrolysis from the known electro-chemical equivalents of different substances is not referred to; indeed, an electro-chemical equivalent does not seem to be anywhere defined. But

what strikes one as strange indeed is that in the chapter on thermo-electricity Peltier's name is only mentioned in connection with an illustration showing what is called his "thermo-electric pince." Not a word is said on the subject of the Peltier effect, or the Thomson effect, not to speak of the bearing of these on thermo-electric theory! Again, no mention appears to be made of any form of secondary cell except that of Plante-: surely some of the modern forms now so largely in use in practice for electric lighting, traction, &c:, might have been figured and described.

The next section of theory, electro-magnetism, has three chapters devoted to it. The main phenomena are well described, and excellently illustrated by diagrams. Here the only forms of tangent and sine galvanometer figured are those of Pouillet (one of these (p. 337) has an enormous needle). Some of the splendid instruments which have been made for absolute measurements (for example, Fitzgerald's tangent galvanometer) ought surely to find a place in a work like the present, published as it is at a time when currents, &c, are no longer measured in arbitrary units, and their determinations are as far as possible divested of errors arising from instrumental peculiarities and accidents of place. A definition might also have been given here of the electro-magnetic unit of current, with some indication, where the constant of a galvanometer is referred to, of how it is possible to measure currents in absolute units, and the importance in this respect of electro-magnetic instruments, the constants of which can be determined from their dimensions and arrangement. At p. 333 a current of so many amperes is referred to as producing a certain force at the needle, but we have not anywhere, so far as we have been able to discover, a definition of an ampere.

The following passage (p. 369) apparently quoted from Faraday's " Researches," was at first sight rather startling: "In this state of circumstance(s) the force of the electromagnet was developed by sending an electric current through its coils, and immediately the image of the lampflame continued magnetic" It is almost needless to say that a reference to the " Researches " showed that the copyist had dropped out a line from Faraday's account of the actual phenomenon, which was not exactly that asserted in the quotation. After "flame" supply the words " became visible, and continued so as long as the arrangement."

The second part of the book is most excellent. All applications of electricity of any importance are fully described, and magnificent cuts, without stint, illustrate in the clearest manner the marvellous and complex contrivances and arrangements now in use in the various systems of telegraphy and telephony, electric lighting, &c, &c. Full-page plates of the illumination of Tunis by the search-lights of the French fleet, the electric light in use in the erection of a great Parisian magasin, the head-light of a locomotive illuminating the track, the interior of one of the Paris forts during the siege, and other subjects, serve to show the great part now played by electricity in all branches of industry and the arts, even including warfare, slow as that is in some respects to profit by the latest results of scientific invention. No book could form a more attractive and useful present for a boy with a taste for mechanics and practical electrical

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