Copyright
Abraham Clark Freeman.

The American journal of science online

. (page 1 of 97)
Online LibraryAbraham Clark FreemanThe American journal of science → online text (page 1 of 97)
Font size
QR-code for this ebook


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/|




:::::::::::::::s:::n::s:::sssssssis



The American
journal of science



3 2044 106 428 659






W. O. FARLOW



Digitized by VjOOQlC



Digitized by VjOOQlC



Digitized by VjOOQlC



Digitized by VjOOQlC



Digitized by VjOOQlC



THE

AMERICAN

JOURNAL OF SCIENCE.

Editor: EDWARD S. DANA.

ASSOCIATE EDITORS

Professors GEO. L. GOODALE, JOHN TROWBRIDGE,
W. G. FARLOW AND WM. M. DAVIS, of Cambridge,

Professors A. E. VERRILL. HENRY S. WILLIAMS and
L. V. PIRSSON, of New Haven,

Professor GEORGE F. BARKER, of Philadelphia,

Professor JOSEPH S. AMES, of Baltimore;,

Mr. J. S. DILLER, of Washington.



FOTTBTE SEBIES.
VOL. XVII— [WHOLE NUMBER, CLXVIL]

WITH TWENTY-FOUR PLATES.



NEW HAVEN, CONNECTICUT.
1904



Digitized by VjOOQIC



THE TUTTLE, MOREHOUSE A TAYLOR PRE66.



Digitized by VjOOQlC



CONTENTS TO VOLUME XVII.



Number 97.

Paffe
Abt. I. — Variation of Potential along the Transmitting

Antenna in Wireless Telegraphy; by C. A. Chant 1

II. — Studies of Eocene Mammalia in the Marsh Collection.

Peabody Museum ; by J. L. Wobtman 23

III. — Initial Stages of the Spine on Pel^e ; by T. A. Jaogab,

Jb 34

IV. — Action of the Halogen Acids upon Vanadic Acid ; by

F. A. GooceandR. W. Cubtis 41

V. — Development of some Paleozoic Bryozoa; by E. R.

CUMINGS 49

VI. — Effects on Rare Earth Oxides produced by Radium-
Barium Compounds and on the Production of Perma-
nently Luminous Preparations by Mixing the Latter
with Powdered Minerals ; by C. Baskbbville and G.
F. KuNz 79

VII. — Numbers of Nuclei produced bv Shaking Different

Liquids and Allied Results ; by C. Babus 81

SCIENTIFIC INTELLTGKNCB.

Cfiemistry and Physics — Titrations with PotaBsium lodate, L. W. Andbbws,
85. — Oxidation of Platinum, L. Wohler : Production of High Vacua for
Distillation, E. Erdman, 86. — Method of Crystallizing difficultly Soluble
Substances, A. de Schulten ; Fractional Distillation, S. Young : Elektro-
Metallorgie, W. Bouchers : New Form of Galvanometer, W. Einthovbn,
87. — Magnetic Properties of Systems of Corpuscles describing Circular
Orbits, J. J. Thouson, 88. — Laboratory Physics, D. C. Miller : Physical
Laboratory Manual for Secondary Schools, S. E. Coleman, 89. — Elements
of Electromagnetic Theory, S. J. Barnett, 90.

Geology and Mineralogy — United States Geological Survey, 90. — New York
State Museum : Geology of Worcester, Mass., J. H. Perry and B. K.
Emerson, 91. — Paleontology and Stratigraphy of the Marine Pliocene and
Pleistocene of San Pedro, California, R. Arnold : Postglacial and Inter-
ghicial (?) Changes of Level at Cape Ann, Massachusetts, R. S. Tarr ;
With a Note on the Elevated Beaches, J. B. Woodward, 93. — Latest and
Lowest Pre-Iroquois Channels between Syracuse and Rome, New York, H.
L. Fairchild : Contributions to the Tertiary Fauna of Florida, etc., W.
H. Dall : Spinel Twins of Pyrite, W. NicoL : Ramosite not a Mineral, L.
McI. LUQT7ER, 98. — List of New York Mineral Localities, H. P. Whitlock,
94.

Miscellaneous Scientijic Intelligence— InteTnAtional Catalogue of Scientific
Literature, 94. — National Academy of Sciences ; Astronomical Observatory
of Harvaid College, E. C. Pickering, 95. — Beitrftge zur Chemischen
Physiologie, F. Hofmeister, 96.

Obituary — Herbert Spencer, 96.



Digitized by VjOOQIC



IV CONTENTS.



Number 98.

Pace

Art. VIII. — Properties of a Radio-active Gas found in the
Soil and Water near New Haven ; by H. A. Bumstead
and L. P. Wheeler 97

IX. — Structure of the Upper Cretaceous Turtles of New
Jersey : Adocus, Osteopygis, and Propleura ; by G. R.
Wieland. (With Plates I-IX) 112

X. — Studies of Eocene Mammalia in the Marsh Collection,
Peabody Museum ; by J. L. Worth an 133

XI. — Structure of the Piedmont Plateau as shown in Mary-
land ; by E. B. Mathews. (With Plate X) 141

XII. — Direct Micrometric Measurement of Fog Particles;

by C. Barus 160

scientific intelligence.

Chemistry and Physics — Formation of Ozone, E. Goldstein : Peculiar Prop-
erty of Some Hjdrated Salts, A. de Schulten, 171. — Attempts to Prepare
Nitrogen Fluoride, Bupp and Geisbl : Qnantitative Chemical Analysis, C.
R. Fbesenius, 172. — Analytical Chemistry of Uraniam, H. Bbearley :
Chemical Calculations, H. L. Wells : Solar Radiation and the Pressure
of Light, PoTNTiNG, 173. — Blondlot^s n-rays, Blondlot, 174. — ^Rowland
Effect, HmsTEixr, 175.

Cfeology and Natural History— -TlmteA States Geological Survey, 175. —
Geology of the Hawaiian Islands, W. H. Dall : Geological Commission,
Cape of Good Hope, G. S. Constobphine, 177. — Geological Society of
South Africa, 178. — Action of Radium, Roentgen Rays and Ultra- Violet
Light upon Minerals and Gems, Kunz and Baskerville : Optical Charac-
ters of Anthophyllite : a Correction, C. H. Wabren : Chemical Comx>osi-
tion of Igneous Rocks expressed by means of Diagrams, J. P. Iodinob, 179.
— Petrographisches Prakticum, R. Rheinisch : Les Roches alcalines carac-
terisant. la Province p^trographique d'Ampasindava, A. Lacroix, 180. —
Notes on the Rocks of Nngsuaks Peninsula and its Environs, Greenland,
W. C. Phalen : Monograph of the Coccidas of the British Isles, R. New-
stead, 181. — Catalogue of the Lepidoptera PhaleBUSB in the British Museum,
G. F. Hahpson : General Zoology, C. W. Dodge, 182.

Miscellaneous Scientific Intelligence — American Association, 182. — Carnegie
Institution of Washington, Year Book, No. 2, 1908 : Physikalisch-chem-
isohes Centralblatt, 188. — Description of the Brains and Spinal Cozds of
Two Brothers dead of Hereditary Ataxia, L. F. Barker : Field Columbian
Museum : Planetary System, F. B. Taylor : Metallic Ornaments of the
New York Indians, W. M. Beauchahp : Queries in Ethnography, A. G.
Keller : Ejiowledge Diary and Scientific Handbook for 1904, 184.



Digitized by VjOOQIC



^'ONTENTS.



. Number 99.

Paffe

Art. XIII. — Geology of the North End of the Taconic

Range ; by T. N. Dale. (With Plate XI) 185

XIV. — Notes on some California Minerals ; by W. T.

SCHALLER 191

XV. — Crystallographical and Chemical Notes on Lawsonite ;

by W. T. SoHALLER and W. F. Hillebrand 196

XVI. — Determination of Nitrites in Absence of Air; by L

K. Phelps 198

XVIL — Use of Ferrous Sulphate in the Estimation of Chlor-
ates and Bromates ; by I. K. Phelps 201

XVIII. — Studies of Eocene Mammalia in the Marsh Collec-
tion, Peabody Museum; by J. L. Wortman 203

XIX. — Notes on a New Meteorite from Hendersonville,
N. C.y and on additional pieces of the Smithville, Tenn.,
Fall; byL. C.Glenn 216

XX, — Periodic Migrations between the Asiatic and the

American Coasts of the Pacific Ocean ; by J. P. Smith 217

XXI. — Triticites, a New Genus of Carboniferous Foramin-

ifers ; by G. EL Girty 234

XXII.— Prismatic Crystals of Hematite; by G. W. McKbe 241

SCIENTIFIC INTELLIGENCK.

Chemistry and Physics — Attempt at a Chemical Conception of the Universal
Ether, D. J. Msndbl^bff : Gold Fluoride, V. Lenhbb, 248. —Separation
of Radimn from Barium, Marckwald : Edssociation of the Alkaline Car-
bonates, P. Lebeau : Combination of Saccharose with Certain Metallic
Salts, D. GAT7THIEB, 244. — Density of Chlorine, Moissan and Jassoneix :
Doppler Effect in Electrical Sparks, A. Haobnbach : Effect of Tempera-
ture on Ionization by ROntgen Rays, R. K. McCluno, 245. — Arc in
Metallic Vapors in an Exhausted Space, E. Wkintraub : Electricity and
Magnetism ; Elementary Text-Book Theoretical and Practical, R. T.
Qlazebrook, 246. — Mechanics, Molecular Physios and Heat, R. A. Milli-
KAif : Treatise on Thermodynamics, M. Planck, 247.

Oeoloffy — Coral Reefs of the Maldives, A. Agassiz : Note on the Classifica-
tion of the Carboniferous formation of Kansas, H. S. Williams, 248. —
Einffihrung in die Palftontologie, G. Steinmann : Structure of the Pied-
mont Plateau as shown in Maryland, E. B. Mathews : Western Australia
Geological Surrey, 249.— Evolution of Earth Structure, T. M. Rbadb, 250.

MiBceUaneous Scientific Intelligence— Smithaomaji Institution, Report for
1903, 251. — Smithsonian Miscellaneous Collections, Quarterly Issue:
Weather Bureau, U. S. Department of Agriculture : Scientia, 252.

Obituary— Dt, Charles Emerson Bebcher : Professor Karl Alfred von

ZlilKL.



Digitized by VjOOQIC



VI CONTENTS,



Number 100.

Piwre

Art. XXni. — Criteria relating to Massive-Solid Volcanic
Eruptions; by I. C. Russell 263

XXIV. — New Nepheline Rock from the Province of Ontario,

Canada; by F. D. Adams - 269

XXV. — Note on a Calcite-Prehnite Cement Rock in the Tuff

of the Holyoke Range ; by B. K. Emebson 277

XXVI.— Developmental Changes in some Common Devo-
nian Brachiopods ; by P. E. Raymond. (With Plates
XII-XVIII) 279

XXVII.— Studies in the Cyperaceae; by T. Holm. XXL
New or little known species of Carex. (With figures in
the text, drawn by the author) 301

XXVin. — Characters of Pteranodon (Second Paper); by G.

F.Eaton. (With Plates XIX and XX) 318

XXIX. — PalfiBontological Evidence for the Original Trituber-

cular Theory ; by H. F. Osbobn. (With Plate XXI) .. 321

SCIENTIFIC INTELLIGENCE.

Chemistry and Physics — Gases Occluded or Evolved by Radium Bromide^
Dewab and Curie : Uranyl Double Salts, Rimbach, BCrgeb and Grewb,
324. — Presence of Formic Aldehyde in the Atmospheric Air, H. Henriet :
Revision of the Atomic Weight of Iron, Baxter, 335. — Method of Separa-
ting Iron and Aluminium, Lecl&re : Phosphorescence, A. Dahms : Prelim-
inary Measurements of the Short Wave Lengths discovered by Schumann,
326. — Heating effect of the Radium Emanation, Rutherford and Barnes :
Nature of the Emanations from Radium, Kelvin, 327.

Geology and Natural History — United States Geological Survey : Glacial
Geology of Tasmania, J. W. Gregory, 328. — Report on a Geological
Reconnoissance of the Iron Region of Angat, Bulacan, H. D. McCaskxy :
Mineral Tables for the Determination of Minerals by their Physical Proper-
ties, A. S. Eakle : Meteorite Catalogues : Fauna and Geography of the
Maldive and Laccadive Archipelagoes, J. S. Gardiner, 829. — North
American Fauna, No. 23, Index Generum Mammalium, T. S. Palmer, 330.

Miscellaneous Scientific Intelligence — Christian Faith in an Age of Science,
W. N. Rice, 330. — Beitrftge zur chemischen Physiologic, F. Hofmeistbr,
331. — Astronomical Observatory of Harvard College : Publications of the
United States Naval Observatory : Wliere did Life Begin ? G. H. Scribner .
Field Columbian Museum : Bureau of American Ethnology ; Twentieth
Annual Report to the Secretary of the Smithsonian Institution, 1898-99,
332.



Digitized by VjOOQIC



CONTENTS. Vll



Number 101.

T&ge
Art. XXX. — Recent Changes in the Elevation of Land and

Sea in the Vicinity of New York City ; by G. W.

TUTTLE.. 333

XXXI. — Geology of Brome Mountain, one of the Montere-

gian Hills ; by J. A. Dbessbk 347

XXXII. — Crystallization of Molybdenite ; by A. J. Moses . 369
XXXI 11. — Behavior of Typical Hydrous Chlorides when

heated in Hydrogen Chloride ; by F. A. Gooch and F.

M. McClbnahan 365

XXXIV. — Stegomus Longipes, a New Reptile from the

Triassic Sandstones of the Connecticut Valley; by B.

K Emebson and F. B. Loomis. (With Plate XXII) .- 377
XXXV. — Note on the probable Footprints of Stegomus

Longipes ; by R. S. Lull 381

XXXVI. — Canyon City Meteorite from Trinity County, Cal-
ifornia ; by H. A. Ward 383

XXXVII. — Two Microscopio-Petrographical Methods; by

F. E. Wright 385

XXXVIII. — Denncleating Effect of Rotation in case of Air

Stored over Water; by C. Babur and A. E. Watson .. 392



SCIENTIFIC INTELLIGENCE.

Chemistry and Physics — Blue Color of Basic Lanthanum Acetate and Iodine,
W. BiLTz: Yellow Antimony, Stock and Guttmann, 395.— Action of
Carbon upon Lime at the Temperature of Fusing Platinum, Moissan :
Two Sodium-Ferric Snlphates, Skrabal ; Grundlinien der Anorganischen
Chemie, W. Ostwald, 396. —Manual of Qualitative Chemical Analysis, J.
F. McGrboort : Influence of Temperature and Pressure on the Absorp-
tion and Diffusion of Hydrogen by Palladium, G. N. St. Schmidt, 397. —
Study of the Radio-activity of Certain Minerals and Mineral Waters, R. J.
Stbctt: Atmospheric Radio-activity in High Latitudes, G. C. Simpson,
398. — Optical Properties of Vitreous Silica, Gifford and Shenstone : Ter-
restrial Magnetism, 399.

Geology and Natural History— JJnited States Geological Survey, 399. — Fossil
Footprints of the Jura- Trias of North America, R. S. Lull, 402. — Non-
metallic Minerals; their Occurrence and Uses, G. P. Merrill, 405. —
Lehrbnch der Mineralogie, M. Bauer : Annual Bulletin of the Mineral
Resources of Kansas, 1908, E. Haworth : Bibliography of the Geology,
Mineralogy and Paleontology of Brazil, J, C. Branner : Willamette
Meteorite, H. A. Ward, 406.— British Tyroglyphidae, A. D. Michael, 407.

Miscellaneous Scientific Intelligence — National Academy of Sciences, 408. —
Report of the Superintendent of the Coast and Geodetic Survey, showing
the Progress of the Work from Jaly 1, 1902 to June 80, 1903 : 1900 Solar
Elclipse Expedition of the Astrophysioal Observatory of the Smithsonian
Institution, S. P. Langley and C. G. Abbot : Physique du Globe et
Meteorologie, A. Beroet, 409. — Ostwald 's Klassiker der Eixacten Wissen-
schaften : Studies in Heterogenesis, H. C. Bastian, 410.

Obituary — M. F. A. FouQuA : M. Henri Perrotin : Professor Fredrik
Adam Smitt : Dr. James Hyatt.



Digitized by VjOOQIC



VIU CONTENTS.



Number 102.

Page
Charles Embbson Bkecheu (with a Portrait, Plate XXIII) 411



Art. XXXIX. — DinoBaur Footprints from Arizona ; by E.

S. RiGGS 423

XL. — New Habit for Chalcopy rite ; by R. W. Richards... 425

XLI. — Molecular Weights of Liquids, with a few Words

about Association ; by C. L. Spkyers 427

XLIL — Relation of Mass Action and Physical Affinity to
Toxicit}^, with incidental discussion as to how far elec-
trolytic dissociation may be involved ; by J. B. Dandeno 437

XLIII. — Tourmaline from San Diego County, California ;

by D. B. Sterrett. (With Plate XXIV) 460

XLIV. — Limit of Error in the Volumetric Determination of

Small Amounts of Gold ; by R. N. Maxson 466

SCIENTIFIC INTELLIGENCE.

Chemistry and Physic*— Hydrates in Solution, H. C. Jones : Microecopical
Method of Determining Molecular Weights, G. Babger, 471. — Rubidium-
Mercuric Double Salts, Grossmann : Zirconium Tetra-iodide, Stabler
and Denk, 472.— Use of the Thermal Junction in the Ultra- Violet, A.
PPL<tQEB : Internal Friction of Nitrogen, S. W. Holman, etc. : Damping
of Electrical Oscillations, Bjerknes, etc., 473.— ^Compressibility of Solids,
J. Y. Buchanan, 474.

Oeology and Natural History^Uniied States Geological Survey, 477. — Atoll
of Funafuti; Borings into a Coral Reef and the Results, Sollas, 478. —
Revision of the Paleozoic Bryozoa, E. O. Ulrich and R. S. Bassler, 479.
— Attempt to Classify Paleozoic Batrachian Footprints, G. F. Matthew :
Geology, T. C. Chamberun ond R. D. Salisbury, 480. — Mineral Resources
of the United States for the Calendar year 1902, D. T. Dat : Fragmenta
Florae Philippinae, J. Perkins, 481. — Botanical Publications by the
Bureau of Govei-nment Laboratories at Manila, 482.

Miscellaneous Scientific Intelligence — Wilhelm Ostwald, P. Walden, 488. —
Changes in the Transparency of the Elarth's Atmosphere : Alpheus Hyatt
Memorial Fond for Field Lessons : Altitudes in the Dominion of Canada,
J. White : Publication of the Earthquake Investigation Committee in
Foreign Languages : Clarkson Bulletin, Vol. I, No. 2, April, 1904, 484.

Index to Vol. XVII, 485.



Digitized by VjOOQIC



TH E



AMERICAN JOURNAL OF SCIENCE

[FOURTH SERIES.}



Art. I. — The Variation of Potential along the Transmitting
Antenna in Wireless Telegraphy ; by C. A. Chant.

I. Introduction.

In a former paper* illustrations were given of the manner
in which standing waves are formed on a free-ending wire
wben the electrical disturbance is produced by electrostatic
induction from a Hertzian oscillator at the other end of the
wii^. The present communication contains a somewhat de-
tailed account of an examination of the aerial wire used to
radiate the waves in wireless telegraphy ; andj in a section at
the end, a brief account of a continuation of the former experi-
ments.

The problem of the electrical oscillations about a free-end-
ing wire has been treated from a rigid theoretical basis by
Abraham,! who determined the electric and magnetic forces
at any point in the field by directly integrating the Maxwel-
lian equations. For the purposes of analysis the wire was
considered to have the form of a very elongated paraboloid
of revolution, and the field to vary in such a way that the
electric lines of force ended perpendicular to its surface.
Sarasin and de la Rive4 and others had compared the oscilla-
tions about a wire to those in an open pipe ; but, as Abraham
remarks, though the relations are essentially similar, the anal-
ogy must not be pushed too far, In the pipe the radiation is
from within outwards, and is greatest in the direction of the

*C. A. Chant, The Variation of Potential along a Wire Transmitting
Electric Waves ; this Journal, xv, p. 54, 1903; Phil. Mag. [6], v, p. 331,
1908.

t M. Abraham, Ann. der Physik, ii, p. 32, 1900.

X E. Sarasin and L. de la Rive, Archives des Sciences Physiques et Natu-
reUes, Geneve, xxiii, p. 113, 1890.

Am. Jour. Soi. — Fourth Series, Vol. XVII, No. 97.- January, 1904.

1



'Digitized by VjOOQlC



2 C. A, Cha/ni — Variation of Potential along the

axis ; while in the electro-magnetic case tlie radiation is from
without inwards, being limited by the surface of the wire, and
on account of the transversality of the vibrations there is no
radiation along the axis. Moreover, in the air-vibrations there
is a displacement of the entire system of nodes and loops
towardsthe open end, while, with the electrical oscillations, to
a first approximation^ there is no such displacement. On a
closer examination, however, there is found to be a displace-
ment of this kind, variable with the frequency. The phase of
the advancing waves alters in a discontinuous manner, some-
what as in the vibrations of a plucked string.*

When two wires are used, as in Lecher's arrangement, the
radiation in the direction of the axis does not vanish, and the
analogy to the open pipe is more marked. There is then a
decided displacement of the nodes and loops, well exhibited in
an investigation by de Forest.f

The best acoustical analogy to a wire connected at one end
to earth or to a large capacity and free at the other seems to
be a closed pipe, gas-pressure in the pipe corresponding to
potential or charge in the case of the wire. Here there is a
displacement of the nodes and loops, but it is very small, and
only the odd harmonics are present in the two cases. Of
course a rod clamped at one end is similar to the closed pipe.

Birkeland and Sarasin,:^ ^^ thoxr investigation of the field
about a free-ending wire, explored with a circular resonator,
and found the first node distant from the end by one-half the
circumference of the resonator (a result similar to that obtained
by Sarasin and de la Eive in their investigation on two parallel
wires, and ascribed ' by them to the geometrical form of the
resonator), and other nodes regularly spaced along the wire at
intervals equal to twice the diameter of the resonator. The
form of the nodal surfaces in the space about the wire obtained
by them agrees with that deduced by Abraham.

Slaby's theoretical treatment§ of the problem is much sim-
pler than Abraham's, and from his results he was led to his
method of syntonic telegraphy. He takes the so-called " tele-
graphic equation,"

hi hH _ 1 hH

' ht 'bf'C^ bx''

where i is the current strength at any time at a place x on the

*Helmholtz, SensatioDB of Tone, p. 54 ; Ravleigh, Theory of Sound, art.
146.

t L. de Forest, this Journal, viii. p. 58, 1899.

JK. Birkeland and E. Sarasin, Comptes Rendus, cxvii, p. 618, 1893.

§A. Slaby, Lond. Electrician, vol. xlvi, Jan. 18, 1901; also vol. xlix,
April 25, 1902.



Digitized by VjOOQIC



Transmitting Antenna in Wireless Telegraphy. 3

antenna, and E„ L„ C„ are the resistance, self-induction and
capacity per unit length of the wire. A solution* is

i = A e cos vp t sm - x ,



where T = 4VLC, I is length of wire, A is a constant and R,
L, C, relate to the whole length of the wire. The frequency
is 1/T and X = 4rZ. From this solution it should follow that
the disturbance varies according to the simple harmonic law,
and that the free end of the wire is a potential loop, the lower
end a potential node.

II. £kperimental Arrangements and Results,
In the present investigation all the wires explored were of
bare copper of diameter 7™°* and were stretched horizontally
on the tops of wooden poles about i'S"" high and I'S"" from
the wall of the room in which the experiments were made.
This room was a large hall, on the first flat, about 22™ long,
12™ wide and with a ceiling 13™ high. The manner of exam-
ining the wire at various points in its length was precisely
similar to that in the former research. The induction coil and
interrupter, the magnetometer and the method of taking read-
ings were identical with those used earlier and need not be
described again here.

In most of the work the detector was the one used before,
but during the course of the experiments it was broken and
another, similar to it and indistinguishable from it in its beha-



Online LibraryAbraham Clark FreemanThe American journal of science → online text (page 1 of 97)