&
PROCEEDINGS
OF THE
ROYAL SOCIETY OF LONDON.
From April 23, 1896, to February 18, 1897
LONDON:
HARRISON AND SONS, ST. MARTIN'S LANE,
in ©rhinarg to |>w Paj
MDCOCXCT1I.
Q
LONDON:
HARRISON ANJ> SONS, PEINTEES IN ORDINARY TO HER MAJESTY,
ST. MARTIN'S IANE.
CONTENTS.
-y <V
ERRATA.
J\To. 363.
Page 272, line 14 from bottom, for Dr. George Murray read Dr. John Murray.
No. 364.
„ 298, „ 15 „ top, „ Marcli, 1896, read February 26, 189(5.
T^..i? j
ERRATUM.
PROCEEDINGS, No. 364
Page 313, line 23, for Philip P. Lenard, read Philipp Lenard.
JC.JL.
Dublin 35
The Electromotive Properties of the Electrical Organ of Malapterurus
electricus. By Francis Gotch, M. A. (Oxon.), F.R.S., and G. J. Burch,
M.A. (Oxon.) 37
The Occurrence of nutritive Fat in the Human Placenta. A Pre-
liminary Communication. By Thomas Watts Eden, M.D., M.R.C.P. 40
Note on the Larva and the Postlarval Development of Leucosolenia
variabilis, H. sp., with Remarks on the Development of other
Asconidse. By E. A. Minchin, M.A., Fellow of Merton College,
Oxford ... 42
CONTENTS.
VOL. LX.
No. 359.
PaKe
Meeting of April 23, 1896 (Meeting for Discussion) ................................ 1
Meeting of April 30, 1896, with List of Papers read ................................ 1
Meeting of May 7, 1896, with List of Papers read .................................. 2
List of Candidates recommended for Election ......................................... 2
Meeting of May 21, 1896, with List of Papers read ................................ 3
Annual Meeting for Election of Fellows .................................................. 4
Meeting of June 4, 1896, with List of Papers read .................................... 4
Meeting of June 11, 1896, with List of Papers read ................................ 0
Meeting of June 18, 1896, with List of Papers read ............................... . 6
Angular Measurement of Optic Axial Emergences. By William
Jackson Pope ................................................ ............................................. 7
On Colour Photography by the Interferential Method. By G. Lipp-
mann, Professor of Physics, Faculty of Sciences, Paris ........................ 10
Note on Photographing Sources of Light with Monochromatic Kays.
By Captain W. de W. Abney, C.B., D,C.L., F.E.S ................................. 13
On the Determination of the Photometric Intensity of the Coronal
Light during the Solar Eclipse of 16th April, 1893. By Captain W.
de W. Abney, C.B., D.C.L., F.E.S., and T. E. Thorpe, LL.D., F.E.S. 15
The Total Eclipse of the Sun, April 16, 1893. Eeport and Discussion
of the Observations relating to Solar Physics. By J. Norman
Lockyer, C.B., F.E.S ..................................................................................... 17
On some Palaeolithic Implements found in Somaliland by Mr. H. W.
Seton-Karr. By Sir John Evans, K.C.B., D.C.L., Treas. and
Y.P.E.S ..................................................................................................... ... 19
On the Liquation of certain Alloys of Gold. By Edward Matthey,
F.S.A., F.C.S., Assoc. E.S.M ..................................................................... 21
On the Occurrence of the Element Gallium in the Clay-Ironstone of
the Cleveland District of Yorkshire. Preliminary Notice. By W.
N. Hartley, F.E.S., Professor of Chemistry, and Hugh Eamage,
A.E. C.S.I., F.I.C., Assistant Chemist in the Eoyal College of Science,
Dublin ............................................................................................................ 3^
The Electromotive Properties of the Electrical Organ of Malapterurus
electricus. By Francis Gotch, M.A. (Oxon.), F.E.S., and G. J. Burch,
M.A. (Oxon.) ................................................................................................ 37
The Occurrence of nutritive Fat in the Human Placenta. A Pre-
liminary Communication. By Thomas Watts Eden, M.D., M.E.C.P. 40
Note on the Larva and the Postlarval Development of Leucosolenia
variabilis, H. sp., with Eemarks on the Development of other
Asconidse. By E. A. Minchin, M.A., Fellow of Merton College,
Oxford... .................................................................... 42
IV
Page
Helium and Argon. Part III. Experiments which show the
Inactivity of these Elements. By William Eamsay, Ph.D., F.E.S.,
and J. Norman Collie, Ph.D., F.E.S.E , 53
On the Amount of Argon and Helium contained in the Gas from the
Bath Springs. By Lord Eayleigh, Sec. E.S 56
On the Changes produced in Magnetised Iron and Steels by cooling to
the Temperature of Liquid Air. By James Dewar, LL.D., F.E.S.,
Fullerian Professor of Chemistry in the Eoyal Institution of Great
Britain, and J. A. Fleming, M.A., D.Sc., F.E.S., Professor of Elec-
trical Engineering in University College, London 57
On the Electrical Eesistivity of Bismuth at the Temperature of Liquid
Air. By James Dewar, LL.D., F.E.S., Fullerian Professor of
Chemistry in the Eoyal Institution, and J. A. Fleming, M.A., D.Sc.,
F.E.S., Professor of Electrical Engineering in University College,
London 72
On the Electrical Eesistivity of Pure Mercury at the Temperature of
Liquid Air. By James Dewar, LL.D., F.E.S., Fullerian Professor
of Chemistry in the Eoyal Institution, and J. A. Fleming, M.A.,
D.Sc., F.E.S., Professor of Electrical Engineering in University
College, London 76
On the Magnetic Permeability and Hysteresis of Iron at Low Tem-
peratures. By J. A. Fleming, M.A., D.Sc., F.E.S., Professor of
Electrical Engineering in University College, London, and James
Dewar, LL.D., F.E.S., Fullerian Professor of Chemistry in the Eoyal
Institution, &c 81
No. 360.
Observations on. Atmospheric Electricity at the Kew Observatory. By
C. Chree, Sc.D., Superintendent 96
On the unknown Lines observed in the Spectra of certain Minerals.
By J. Norman Lockyer, C.B., F.E.S 133
The Eelation between the Eefraction of the Elements and their Chemical
Equivalents. By J. H. Gladstone, D.Sc., F.E.S 140
Selective Absorption of Eontgen Eays. By J. A. M'Clelland, M.A.,
Fellow of the Eoyal University of Ireland' 146
On the Structure of Metals, its Origin and Changes. By F. Osmond
and W. C. Eoberts- Austen, C.B., F.E.S., Professor of Metallurgy,
Eoyal College of Science 148
On the Eelations between the Viscosity (Internal Friction) of Liquids
and their Chemical Nature. Part II. By T. E. Thorpe, LL.D.,
F.E.S., and J. W. Eodger, Assoc. E.C.S .". 152
On the Determination of Freezing Points. By J. A. Harker, D.Sc 154
No. 361.
Etude des Carbures Metalliques. By Henri Moissan 156
Complete Freezing-point Curves of Binary Alloys containing Silver or
Copper, together with another Metal. By C. T. Heycock, M.A.,
F.E.S., and F. H. Neville, M.A 160
Paee
Note of the Radius of Curvature of a Cutting Edge. By A. Mallock.... 164
On the Determination of the Wave-length of Electric Radiation by
Diffraction Grating. By Jagadis Chunder Bose, M.A. (Cantab.),
D.Sc. (Loiid.), Professor of Physical Science, Presidency College,
Calcutta 167
The Effects of a strong Magnetic Field upon Electric Discharges in
Vacuo. By A. A. C. Swinton 179
The Hysteresis of Iron and Steel in a Rotating Magnetic Field. By
Francis G. Baily, M.A 182
A Magnetic Detector of Electrical Waves and some of its Applications.
By E. Rutherford, M.A., 1851 Exhibition Science Scholar, New
Zealand University, Trinity College, Cambridge 184
Magnetisation of Liquids. By John S. Townsend, M.A. (Dub.) 186
On Fertilisation, and the Segmentation of the Spore in Fucus. By
J. Bretland Farmer, M.A., Professor of Botany at the Royal College
of Science, and J. LI. Williams, Marshall Scholar at the Royal College
of Science, London 188
On certain Changes observed in the Dimensions of Parts of the Carapace
of Carcinus mcenas. By Herbert Thompson 195
Phenomena resulting from Interruption of Afferent and Efferent Tracts
of the Cerebellum. By J. S. Risien Russell, M.D., M.R.C.P.,
Research Scholar to the British Medical Association, Assistant
Physician to the Metropolitan Hospital, and Pathologist to the
National Hospital for the Paralysed and Epileptic, Queen's Square.... 199
The Menstruation and Ovulation of Macacus rhesus. By Walter
Heape, M.A., Trinity College, Cambridge 202
No. 362.
The Homogeneity of Helium and of Argon. By William Ramsay,
Ph.D., F.R.S., and J. Norman Collie, Ph.D., F.R.S 206
On the Spectrum of Cyanogen as produced and modified by Spark
Discharges. By W. N. Hartley, F.R.S., Royal College of Science,
Dublin 216
Variation in Portunus depurator. By Ernest Warren, B.Sc., Demon-
strator of Zoology at University College, London 221
Investigations into the Segments! Representation of Movement in the
Lumbar Region of the Mammalian Spinal Cord. By William Page
May, M.D., B.Sc., M.R.C.P., Fellow of University College, London 244
Preliminary Statement on the Development of Sporangia upon Fern
ProthalH. By William H. Lang, M.B., B.Sc., Lecturer in Botany,
Queen Margaret College, and Robert Donaldson Scholar, Glasgow
University 25°
No. 363.
Meeting of November 19, 1896, with List of Papers read 260
The Reproduction and Metamorphosis of the Common Eel (Anguilla
vulgaris). By G. B. Grassi, Professor in Rome
Total Eclipse of the Sun, 1896.- The Novaya Zemlya Observations.
By Sir George Baden-Powell, K.C.M.G., M.P 271
vi
Page
Preliminary Report on the Results obtained with the Prismatic
Camera during the Eclipse of 1896. Bv J. Norman Lockyer, C.B.,
F.R.S 271
Meeting of November 26, 1896, with List of Officers and Council and
List of Papers read 272
Mathematical Contributions to the Theory of Evolution. On Telegony
in Man, &c. By Karl Pearson, F.R.S., University College, with the
assistance of Miss Alice Lee, Bedford College, London 273
On the Magnetic Permeability of Liquid Oxygen and Liquid Air. By
J. A.. Fleming, M.A., D.Sc., F.R.S., Professor of Electrical Engineer-
ing in University College, London, and James Dewar, LL.D., F.R.S.,
Fullerian Professor of Chemistry in the Royal Institution 285
No. 364.— November 30, 1896.
ANNIVERSARY MEETING.
Report of Auditors 296
List of Fellows deceased since last Anniversary 297
elected 297
Address of the President 298
Election of Council and Officers 316
Financial Statement 317 — 320
Trust Funds 321—326
Income and Expenditure Account 327
Table showing Progress and present State of Society with regard to
Fellows , 328
Account of Grants from the Donation Fund.... , 328
Meeting of December 10, 1896, with List of Papers read 329
On Professor Hermann's Theory of the Capillary Electrometer. By
George J. Burch, M.A 329
An Attempt to determine the Adiabatic Relations of Ethyl Oxide. By
E. P. Perman, D.Sc., W. Ramsay, Ph.D., F.R.S., and J. Rose-limes,
M.A., B.Sc _ 336
The Chemical and Physiological Reactions of certain Syiithesised Pro-
teid-like Substances. Preliminary Communication. By John W.
Pickering, D.Sc. (Loiid.) , 337
An Experimental Examination into the Growth of the Blastoderm of
the Chick. By Richard Asshetoii, M.A 349
Meeting of December 17, 1896, with List of Papers read 357
On the Dielectric Constant of Liquid Oxygen and Liquid Air. By
J. A. Fleming, M.A., D.Sc., F.R.S., Professor of Electrical Engineer-
ing in University College, London, and James Dewar, M.A., LL.D.,
F.R.S., Fullerian Professor of Chemistry in the Royal Institution,
&c.... 358
On Subjective Colour Phenomena attending sudden Changes of Illumi-
nation. By Shelford Bidwell, M.A., LL.B., F.R.S.
Vll
Page
368
No. 365.
On the Effect of Pressure in the surrounding Gas on the Temperature
of the Crater of an Electric Arc. Correction of Results in former
Paper. By W. E. Wilson, F.R.S., and G. F. Fitzgerald, F.R.S 377
Influence of Alterations of Temperature upon the Electrotonic Cur-
rents of Medullated Nerve. By Augustus D. Waller, M.D., F.R.S. 383
On the Occurrence of Gallium in the Clay-ironstone of the Cleveland
District of Yorkshire : Determination of Gallium in Blast-furnace
Iron from Middlesbrough. By W. N. Hartley, F.R.S., Professor of
Chemistry, and Hugh Ramage, A.R.C.Sc.L, F.I.C., Assistant Chemist,
Royal College of Science, Dublin 393
Meeting of January 21, 1897, with List of Papers read 408
Experiments in Examination of the Peripheral Distribution of the
Fibres of the Posterior Roots of some Spinal Nerves. Part II. By
C. S. Sherrington, M.A., M.D., F.R.S., Holt Professor of Physiology,
University College, Liverpool 408
Cataleptoid Reflexes in the Monkey. By C. S. Sherrington, M.A.,
M.D., F.R.S., Holt Professor of Physiology, University College,
Liverpool 411
On Reciprocal Iimervation of Antagonistic Muscles. Third Note. By
C. S. Sherrington, M.A., M.D., F.R.S., Holt Professor of Physiology,
University College, Liverpool 414
On Cheiro&trobusi a new Type of Fossil Cone from the Calciferous Sand-
stones. By D. II. Scott, M.A., Ph.D., F.R.S., Hon. Keeper of the
.Todrell Laboratory, Royal Gardens, Kew 417
No. 366.
Meeting of January 28, 1897, with List of Papers read 424
On the Capacity and Residual Charge of Dielectrics as affected by
Temperature and Time. By J. Hopkinson, F.R.S., and E. Wilson.... 425
On the Electrical Resistivity of Electrolytic Bismuth at Low Tempera-
tures, and in Magnetic Fields. By James Dewar. M.A., LL.D.,
F.R.S., Fullerian Professor of Chemistry in the Royal Institution,
and J. A.. Fleming, M.A., D.Sc., F.R.S., Professor of Electrical Engi-
neering in University College, London 425
On the Selective Conductivity exhibited by certain Polarising Sub-
stances. By Professor Jagadis Chunder Bose, M.A., D.Sc 433
Meeting of February 4, 1897, with List of Papers read 437
On the Condition in which Fats are absorbed from the Intestine. By B.
Moore and D. P. Rockwood 438
The Gaseous Constituents of certain Mineral Substances and Natural
WTaters. By William Ramsay, F.R.S., and Morris W. Travers,
T> Q. 442
JD.ioC
Some Experiments on Helium. By Morris W. Travers, B.Sc 449
On the Gases enclosed in Crystalline Rocks and Minerals. By W. A.
Tilden, D.Sc., F.R.S
viii
Page
\
On Lunar Periodicities in Earthquake Frequency. By C. G. Knott,
D.Sc., Lecturer on Applied Mathematics, Edinburgh University
(formerly Professor of Physics, Imperial University, Japan) 45'
No. 367.
Meeting of February 11, 1897, with List of Papers read ...- 466
The Oviposition of Nautilus macromphalus. By Arthur Willey, D.Sc.,
Balfour Student of the University of Cambridge. Communicated
by Alfred Newton, M.A., F.R.S., on behalf of the Managers of the
Balfour Fund 467
On the Regeneration of Nerves. By Robert Kennedy, M.A., B.Sc.,
M.D. (Glasgow). Communicated by Professor McKeiidrick, F.R.S. 472
Meeting of February 18, 1897, with List of Papers read 474
On the Iron Lines present in the Hottest Stars. Preliminary Note.
By J. Norman Lockyer, C.B., F.R.S 475
On the Significance of Bravais' Formulae for Regression, &c., in the case
of Skew Correlation. By G. Udny Yule. Communicated by Pro-
fessor Karl Pearson, F.R.S 477
Mathematical Contributions to the Theory of Evolution — On a Form of
Spurious Correlation which may arise when Indices are used in the
Measurement of Organs. By Karl Pearson, F.R.S., University
College, London 489
Note to the Memoir by Professor Karl Pearson, F.R.S., on Spurious
Correlation. By Francis Galton, F.R.S 498
Report to the Committee of the Royal Society appointed to investigate
the Structure of a Coral Reef by Boring. By W. J. Sollas, D.Sc.,
F.R.S., Professor of Geology in the University of Dublin 502
The Influence of a Magnetic Field on Radiation Frequency. Commu-
nication from Professor Oliver Lodge, F.R.S 513
The Influence of a Magnetic Field on Radiation Frequency. Commu-
nication from Dr. J. Larmor, F.R.S 514
Obituary Notices : —
Hermann Kopp i
John Rae v
Franz Ernst Neumann viii
Sir Joseph Prestwich xii
Sir George Johnson , xvi
Henry Newell Martin , xx
Brian Houghton Hodgson xxiii
William Crawford Williamson xxvii
Sir George Henry Richards, K.C.B xxxii
Index xxxvii
Erratum '„, xlvii
PROCEEDINGS
OF
THE ROYAL SOCIETY.
April 23, 1896.
(Meeting for Discussion.)
Sir JOSEPH LISTER, Bart., President, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The following Paper was read for the purpose of opening the
discussion : —
"On Colour Photography by the Interferential Method." By G.
LIPPMANN, Professor of Physics, Faculty of Sciences, Paris.
Communicated by Sir JOSEPH LISTER, Bart., P.R.S.
April 30, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
The Right Hon. Sir Richard Temple, Bart., a Member of Her
Majesty's Most Honourable Privy Council, was admitted into the
Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The following Papers were read : —
I. " Note on Photographing Sources of Light with Monochromatic
Rays." By Captain W. DE W. ABNEY, C.B., D.C.L., F.R.S.
VOL. LX. B
2 Proceedings.
April 30, 1896 — continued.
II. " On the Determination of the Photometric Intensity of the
Coronal Light during the Solar Eclipse of 16th April, 1893."
By Captain W. DE W. ABNEY, .C.B., D.C.L., F.R.S., and T. E.
THORPE, LL.D., F.R.S.
III. " The Total Eclipse of the Sun, April 16, 1893. Report and
Discussion of the Observations relating to Solar Physics." By
J. NORMAN LOCKTER, C.B., F.R.S.
IV. " On some Palaeolithic Implements found in Somaliland by
Mr. H. W. Seton-Karr." By Sir JOHN EVANS, K.C.B., D.C.L.,
Treas. and V.P.R.S.
Hay 7, 1896,
Sir JOSEPH LISTER, Bart., President, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
In pursuance of the Statutes, the names of the Candidates recom-
mended for election into the Society were read from the Chair as
follows : —
Murray, John, Ph.D.
Clarke, Lieut.-Col. Sir George
Sydenham, R.E.
Collie, J. Norman, Ph.D.
Downing, Arthur Matthew Weld,
D.Sc.
Elgar, Francis, LL.D.
Gray, Professor Andrew, M.A.
Hinde, George Jennings, Ph.D.
Miers, Professor Henry Alexander,
M.A.
Mott, Frederick Walker, M.D.
The following Papers were read : —
I. " On the Liquation of certain Alloys of Gold." By E. MATTHEY.
Communicated by Sir G. G. STOKES, F.R.S.
II. " On the Occurrence of the Element Gallium in the Clay- Iron-
stone of the Cleveland District of Yorkshire. Preliminary
Notice." By Professor HARTLEY, F.R.S. , and H. RAMAGE.
Pearson, Professor Karl, M.A.
Stebbing, Rev. Thomas Roscoe
Rede, M.A.
Stewart, Professor Charles,
M.R.C.S.
Wilson, William E.
Woodward, Horace Bolingbroke,
F.G.S.
Wynne, William Palmer, D.Sc.
Proceedings. 3
May 7, 1896— continued.
III. " The Electromotive Properties of Malapterurus ekctricus." By
Professor GOTCH, F.R.S., and G. J. BURCH.
IV. "The Occurrence of Nutritive Fat in the Human Placenta.
Preliminary Communication." By Dr. T. W. EDEN. Commu-
nicated by Dr. PYE SMITH, F.R.S.
The Society adjourned over Ascension Day to Thursday, May 21.
May 21, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The following Papers were read : —
I. " On the Changes produced in Magnetised Iron and Steel by
cooling to the Temperature of Liquid Air." By Professor J.
DEWAR, F.R.S., and Dr. J. A. FLEMING, F.R.S.
II. " Note on the Larva and Post-larval Development of Leuco-
solenia variabilis, H. sp., with Remarks on the Development of
other Asconidse." By E. A. MINCHIN. Communicated by
Professor LANKESTER, F.R.S.
III. " Helium and Argon. Part III. Experiments which show the
Inactivity of these Elements.'' By Professor RAMSAY, F.R.S. ,
and Dr. J. NORMAN COLLJE.
IV. "On the Amount of Argon and Helium contained in the Gas
from the Bath Springs." By LORD RAYLEIGH, Sec. R.S. .
The Society adjourned over the Whitsuntide Recess to Thursday,
June 4.
B 2
4 Proceedings.
June 4, 1896.
The Annual Meeting for the Election of Fellows was held this day.
Sir JOSEPH LISTER, Bart., President, in the Chair.
The Statutes relating to the election of Fellows having been read,
Professor Bonney and Mr. Salvin were, with the consent of the
Society, nominated Scrutators to assist the Secretaries in the examin-
ation of the balloting lists.
The votes of the Fellows present were collected, and the following
Candidates were declared duly elected into the Society : —
Clarke, Lieut. -Col. Sir George
Sydenham, R.E.
Collie, J. Norman, Ph.D.
Downing, Arthur Matthew Weld,
D.Sc.
Elgar, Francis, LL.D.
Gray, Professor Andrew, M.A.
Hinde, George Jennings, Ph.D. Woodwai
Miers, Professor Henry Alexander, F.G.S.
M.A.
Mott, Frederick Walker, M.D.
Thanks were given to the Scrutators.
Murray, John, Ph.D.
Pearson, Professor Karl, M.A.
Stebbing, Rev. Thomas Roscoe
Rede, M.A.
Stewart, Professor Charles,
M.R.C.S.
Wilson, William E.
Woodward, Horace Bolingbroke,
Wynne, William Palmer, D.Sc.
June 4, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
Professor Albert Gaudry, who was elected a Foreign Member in
1895, was admitted into the Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The following Papers were read : —
I. " On the unknown Lines observed in the Spectra of certain
Minerals." By J. NORMAN LOCKYEE, C.B., F.R.S.
II. " On the Electrical Resistivity of Bismuth at the Temperature
of Liquid Air." By Professor J. DEWAE, F.R.S., and Dr. J. A.
FLEMING, F.R.S.
Proceedings. 5
June 4, 1896 — continued.
III. " On the Electrical Resistivity of pure Mercury at the Tempera-
ture of Liquid Air." By Professor J. DEWAR, F.R.S., and Dr.
J. A. FLEMING, F.R.S.
IV. " The Hysteresis of Iron and Steel in a rotating Magnetic Field."
By Professor F. G. BAILY. Communicated by Professor
LODGE, F.R.S.
V. " Observations on Atmospheric Electricity at the Kew Observa-
tory." By C. CHREE. Communicated by Professor G. CAREY
FOSTER, F.R.S.
June II, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
Dr. J. Norman Collie, Dr. A. M. W. Downing, Professor Andrew
Gray, Dr. G. J. Hinde, Dr. F. W. Mott, Rev. T. R. R. Stebbing,
Professor C. Stewart, Mr. W. E. Wilson, Mr. H. B. Woodward, and
Dr. W. P. Wynne were admitted into the Society.
A congratulatory Address to Lord Kelvin, prepared for presentation
to him on the occasion of the jubilee of his professoriate in the
University of Glasgow, was read from the Chair and unanimously
adopted.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The following Papers were read : —
I. " The Relation between the Refraction of the Elements and
their Chemical Equivalents." By Dr. J. H. GLADSTONE, F.R.S.
II. "On the Magnetic Permeability and Hysteresis of Iron at Low
Temperatures." By Dr. J. A. FLEMING, F.R.S., and Professor
J. DEWAE, F.R.S.
III. " On certain Changes observed in the Dimensions of Parts of the
Carapace of Carcinus mcenas." By H. THOMPSON. Communi-
cated by Professor WELDON, F.R.S.
IV. " On the Relation between the Viscosity (Internal Friction) of
Liquids and their Chemical Nature." By Dr. T. E. THORPE,
F.R.S., and J. W. RODGER.
6 Proceedings.
June 18, 1896.
Sir JOSEPH LISTER, Barfc., President, in the Chair.
Lieut.-Colonel Sir Or. S. Clarke and Professor H. A. Miers were
admitted into the Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
Sir J. "W. Dawson exhibited new specimens of Carboniferous
Batrachians.
An oral communication was made by Professor J. A. Fleming,
F.R.S., on behalf of Professor Dewar and himself, to the following
effect :—
In continuing our experiments on the electrical resistance of bis-
muth at low temperatures and in magnetic fields, by the aid of a
powerful electro-magnet, kindly lent to us by Sir David Salomons,
we have observed the fact that a wire of electrolytic bismuth, when
cooled in liquid air to a temperature of —186° C., has its resistance
increased more than fortv-two times if it is at the same time trans-
versely magnetised in a field of 14,000 units. The bismuth, when
cooled in liquid air and thus magnetised, has its electrical resistance
increased more than fifteen times, even when compared with its
resistance at ordinary temperatures and not in a magnetic field.
There is no reason to believe we have reached the limits of this
increase. We reserve further details for a full communication to the
Royal Society later.
The following Papers were read : —
I. " Etude des Carbures Metalliques." By M. HENRI MOISSAN.
Communicated by Professor RAMSAY, F.R.S.
II. " On Fertilisation and the Segmentation, 'of the Spore in
Fucns." By J. B. FARMER and J. L. WILLIAMS. Communi-
cated by Dr. D. H. SCOTT, F.R.S.
III. " Complete Freezing-point Curves of Binary Alloys containing
Silver or Copper together with another Metal." By C. T.
HEYCOCK, F.R.S., and F. H. NEVILLE.
IY. "Note on the Radius of Curvature of a Cutting Edge." By
A. MALLOCK. Communicated by LORD KELVIN, F.R.S,
Y. "A Magnetic Detector of Electrical Waves and some of its
Applications." By E. RUTHERFORD. Communicated by Pro-
fessor J. J. THOMSON, F.R.S.
Angular Measurement of Optic Axial Emergences. 7
June 18, 1896— continued.
VI. " Experimental Proof of van't Hoff's Constant, Dalton's Law.
&c., in very dilute Solutions." By Dr. MEYER WILDERMAXN,
Communicated by Professor FITZGERALD, F.R.S.
VII. " On the Determination of the Wave-length of Electric Radia-
tion by Diffraction Gratings." By J. C. BOSE. Communicated
by LORD RATLEIGH, Sec. R.S.
VIII. " The Effects of a strong Magnetic Field upon Electric Dis-
charges in Vacuo." By A. A. C. SWINTON. Communicated by
LORD KELVIN, F.R.S.
IX. " On the Structure of Metals, its Origin and Changes." By
M. F. OSMOND and Professor ROBERTS- AUSTEN, C.B., F.R.S.
X. "Magnetisation of Liquids." By JOHN S. TOWNSEND. Com-
municated by Professor J. J. THOMSON, F.R.S.
XI. " Selective Absorption of Rontgen Rays." By J. A.
MCCLELLAND. Communicated by Professor J. J. THOMSON
F.R.S.
XII. "On the Determination of Freezing Points." By J. A.
BARKER, D.Sc. Communicated by Professor SCHUSTER, F.R.S.
XIII. " The Menstruation and Ovulation of Macacus rhesus ; with
Observations on the Changes undergone by the discharged
Follicle. Part II." By WALTER HEAPE. Communicated by
Dr. M. FOSTER, Sec. R.S.
XIV. " Phenomena resulting from Interruption of Afferent and
Efferent Tracts of the Cerebellum." By Dr. J. S. RISIEN
RUSSELL. Communicated by Professor V. HORSLEY, F.R.S.
The Society adjourned over the Long Vacation to Thursday,
November 19.
"Angular Measurement of Optic Axial Emergences." By
WILLIAM JACKSON POPE. Communicated by Professor
ARMSTRONG, F.R.S. Received February 7, — Read March
19, 1896.
Crystals belonging to the monoclinic or anorthic systems are rarely
obtained in which the optical orientation is such that a large
crystal face is so nearly perpendicular to a bisectrix that the
apparent optic axial angle as observed in air can be directly measured
by means of the ordinary Fuess apparatus. It thus becomes
8 Mr. W. J. Pope.
necessary to first grind plates of known orientation for optical
examination ; this latter operation is by no means easily performed,
especially in the case of brittle organic substances. Very usually,
however, crystals belonging to the biaxial systems are obtained in
which an optic axis apparently emerges into air through a particular
face ; in these cases the accurate measurement of the angle between
the apparent direction in air of the optic axis and the normal to the
crystal plate becomes an important element in the determination of
the optical constants of the crystal.
The ordinary method of determining this angle is a direct one ;
the crystal is adjusted in the optic axial angle apparatus and a read-
ing is taken for the above emergence, after the position of the
normal to the plate has been found by reflecting a beam of light
down the telescope tube and turning the crystal until the shadow
and reflected image of the crosswires coincide ; the angular differ-
ence between the two readings is then the required apparent angle
of emergence into air. This method of finding the position of the
normal is, however, very tedious, and, unless the crystal plate pos-
sesses a highly polished surface, very inaccurate.
To remedy these defects a method has been devised of indirectly
determining this angle by calculating it from the angle through
which the optic axis is apparently refracted by an oil of high refrac-
tive index. The crystal is mounted and adjusted in the optic axial
angle apparatus in the ordinary way, and a reading is taken for the
optic axial emergence in air; a parallel-sided glass cell containing
a-bromonaphthalene or some other highly refractive liquid is then
raised until it surrounds the crystal, and a second reading is taken
of the apparent emergence of the optic axis. From the difference
between these two angular readings the angle of emergence into air
can be calculated, if the index of refraction of the oil is known.
N
Angular Measurement of Optic Axial Emergences. 9
In the figure, OA is an optic axial direction in the crystal, OB "is
the direction of optic axial emergence into air, and OC is the direc-
tion of emergence into a liquid of refractive index ^u; ON is the
normal to the crystal plate. Then «, the angle of emergence into air,
is NOB, whilst 0, the angle of emergence into the liquid is NOG
and sin*/sin0 = ft-, it is required to calculate the angle «, from
the observed value of a — 6.
Then, since sin a/sin 9 = ^
- = sin{g~ Q— 0)}
/* sin a
__ sin ac cos (y. — 0) — cos a sin (a — 0)
sin a
= cos (a— 0) — cot a sin (a— 0)
cota = cotfa— 0) --
J
— 0)
Or again, since sin a/sin 0 = a,
sin a 4- sin 0
;t — 1 sin a— sin 0
_ sin ^0 + 0) cos |(a— 0)
, a — 0
whence tan - = - -- tan - ........... . (2)
2 yu— 1 2
a form more convenient than (1) for logarithmic calculation.
To test the accuracy of the method, measurements have been made
011 biaxial plates of different optical properties, liquids of various re-
fractive indices being used. The index of refraction of the liquid
employed is conveniently determined with the Ptilfrich refractometer ;
the refraction is so affected by differences of temperature and of
purity that it is necessary to determine it for the liquid as actually
used ; the liquid does not need to be specially purified. The measure-
ments given in the two appended tables were made on plates of
topaz, each of them cut perpendicularly to the acute bisectrix. By
measurement of the optic axial angles, the apparent emergences into
air for sodium light were found to be 53° 24' and 54° 42', respec-
tively.
These two sets of measurements suffice to show that the method
possesses very considerable accuracy, although the values of a— 0
measured are not very large ; the numbers also seem to indicate
10 Prof. G. Lippmann. On Colour
TABLE I. — Plate with angle of emergence in air 53° 24'.
Liquid.
^D.
a-e.
a.
A.
1 -6473
24° 15'
53° 26'
+ 2'
a-Bromonaphthalene. . . .
Benzene . ...
1 -5341
1 -4970
21 50
21 0
53 22J
53 27£
-H
+ 3£
Turpentine
1 '4726
20 20
53 20|
— 3^
1 -4673
20 12
53 21
— 3
1 -4634
20 10
53 28|
+ 4£
Chloroform
1 -4439
19 35
53 19|
— 4i
.Alcohol . . . .
1-3561
17 2
53 15
— 9
\^ater
1 -3327
16 21
53 22
— 2
TABLE II. — Plate with angle of emergence in air 54° 42'.
Liquid.
/*D.
a-9.
a.
A.
Carbon bisulphide
1 -6473
24° 58'
54° 38^'
— 3i'
a-Broinonaphthalene. . . .
1 -5341
1 -4970
22 35
21 41
54 44i
54 44£
+ 2!
+ 2^
1-4726
21 0
54 37
-5
Olive oil .
1 '4673
20 56
54 45
+ 3
1 -4634
20 51
54 47£
+ 5i
Chloroform .
1-4439
20 17
54 42
0
-A.lcoh.ol . . . <
1 • 3561
17 45
54 48£
+ 6£
Watey
1 -3327
16 54
54 37
— 5
that, as would of course be expected, the most accurate results are
obtained with liquids of high refractive index, which give com-
paratively large values of a — 9. By determining the values of a — 0
for each of two optic axes of a given crystal plate, it can easily be
ascertained with what amount of accuracy the plate has been cut
perpendicularly to the bisectrix.
The principle of the method here described may very possibly be
advantageously employed in other branches of optical investigation.
" On Colour Photography by the Interferential Method." By
G. LIPPMANN, Professor of Physics, Faculty of Sciences,
Paris. Communicated by Sir JOSEPH LISTER, Bart., P.R.S.
Received April 14,— Read April 23, 1896.
Colour photographs of the spectrum, or of any other object, are
obtained by the following method. A transparent photographic film
of any kind has to be placed in contact with a metallic mirror during
Photography by the Interferential Method. 11
exposure. It is then developed and fixed by the usual means em-
ployed in photography, the result being a fixed colour photograph
visible by reflected light.
The mirror is easily formed by means of mercury. The glass plate
carrying the film being inclosed in a camera slide, a quantum of
mercury is allowed to flow in from a small reservoir and fill the back
part of the slide, which is made mercury-tight. The plate is turned
with its glass side towards the objective, the sensitised film touching
the layer of mercury. After exposure, the mercury is allowed to
flow back into its reservoir, and the plate taken out for development.
The only two conditions necessary for obtaining colour, trans-
parency of the film and the presence of a mirror during exposure,
are physical conditions. The chemical nature of the photographic
layer has only secondary importance ; any substance capable of giving,
by means of an appropriate development, a fixed colourless photo-
graph, is found to give, when backed by the mirror, a fixed colour
photograph.
We may take, for instance, as a sensitive film, a layer of albumeno-
iodide of silver, with an acid developer; or a layer of gelatino-
bromide of silver, with pyrogallic acid, or with amidol, as deve-
lopers. Cyanide or bromide of potassium may be as usual employed
for fixing the image. In a word, the technics of ordinary photo-
graphy remain unchanged. Even the secondary processes of intensi-
fication and of isochromatisation are employed with full success for
colour photography.
The photographic films commonly in use are found to be opaque,
and formed, in fact, by grains of light-sensitive matter mechanically
imprisoned by a substratum of gelatine, albumen, and collodion.
What is here wanted is a fully transparent film, the light-sensitive
matter pervading the whole of the neutral substratum. How can
such a transparent film be realised? This question remained
insoluble to me for ma,ny years, so that I was debarred trying the
above method when I first thought of it. The difficulty, how-
ever, is simply solved by the following remark. It is well known
that the precipitation of a .metallic compound, such as bromide of
silver, does not take place in the presence of an organic colloid, such
as albumen, gelatine, or collodion. In reality, the metallic compound
is formed, but remains invisible; it is retained in a transparent
modification by the organic substances. We have only, therefore, to
prepare the films in the usual way, but with a stronger proportion of
the organic substratum ; the result is a transparent film. By mixing,
for instance, a gelatinous solution of nitrate of silver with a gelatinous
solution of bromide of potassium, no precipitate is formed, and the
result is a transparent film of dry gelatine containing 15 and even 30
per cent, of the weight of bromide of silver.
12 On Colour Photography by the Interferential Method.
The colours reflected by the film are due to interference : they are
of the same kind as those reflected by soap bubbles or by Newton's
rings. When a ray of definite wave-length falls on the sensitive
plate, it is during exposure reflected back by the mirror, and then
gives rise to a set of standing waves in the interior of the film,
the distance between two successive loops being equal to half the
wave-length of the luminous ray. This system of standing waves
impresses its periodical structure on the film. The photographic
deposit, therefore, takes the form of a grating, a continuous grating,
perfectly adapted for reflecting the particular luminous ray which has
given it birth.
This theory can be subjected to experimental proof. If we ex-
amine a photograph of the spectrum, or any other object by white
light, we observe the following facts. (1.) Colours are seen in the
direction of specular reflection, and are invisible in every other
direction. (2.) The colours change with the incidence; the red
changing successively to green, blue, and violet, when the incidence
grows more oblique. The whole image of the spectrum is dis-
placed, and gradually passes into the infra-red region. (3.) If the
film be gradually moistened, the colour changes in the opposite
direction, from violet to red. This phenomenon is due to the swelling
up of the gelatine or albumen, causing the intervals between the
elements of the grating to become larger. The smaller intervals, corre-
sponding to violet and blue light, gradually swell up to the values
proper to red and infra-red waves. A photograph immersed in water
loses all its colours, these appearing again during the process of drying.
For the same reason, a freshly prepared plate has to be dried before
the correct colours can be finally seen.
We have now to consider the case of compound colours, and to
generalise the former theory, which is only applicable to the action
of simple rays. I beg to subjoin an abstract of this generalised
theory. It will be seen that if a compound ray of definite composi-
tion impresses the plate, it gives rise during exposure to a definite
set of standing waves, which impress their structure on the film, and
impart to the photographic deposit a corresponding definite form.
Though very complex, this can be described as made up of a number
of elementary gratings, each corresponding to one of the simple rays
which contribute the impressing light. When examined by white
light, the reflected ray is shown to have the same composition as the
impressing ray ; white light, for instance, imparts to the photographic
deposit such a structure that it is adapted to reflect white light.
The only a priori condition for the correct rendering of compound
rays, is a correct isochromatisation of the film. This, again, can be
practically effected by known processes, such as have been indicated
by E. Becquerel, Vogel, Captain Abney, and others.
Photographing witli Monochromatic Rays. 13
As a verification of this theory, I beg leave to project on the
screen a series of colour photographs, representing natural objects :
pictures on stained glass, landscapes from nature, flowers, and a
portrait from life. Every colour in nature, including white, and the
delicate hue of the human complexion, is thus shown to be reflected
by a correctly developed photographic film.
It is to be remarked that, as in the case of the spectrum, the
colours are visible only in the direction of specular reflection. If
I had tried to touch up these photographs by means of water colours
or other pigments, these would be made apparent by slightly turning
the photograph ; these pigments remaining visible under every in-
cidence, they would thus be seen to stand out on a colourless back-
ground. Thus the touching up or falsifying by hand of a colour
photograph is happily made impossible.
"Note on Photographing Sources of Light with Mono-
chromatic Rays." By Captain W. DE W. ABNEY, C.B.,
D.C.L., F.R.S. Received March 31,— Read April 30, 1896.
In a paper " On the Production of Monochromatic Light," com-
municated to the Physical Society, and read on the 27th June, 1885,
and which appears in the ' Philosophical Magazine ' for August in
that same year, I stated that by the apparatus then described a
monochromatic image of the sun could be thrown upon the screen.
In the same periodical for June of the same year, Lord Rayleigh
described a plan for obtaining a monochromatic image of an external
object, in which a concave lens was placed behind the slit of a spectro-
scope to produce an image of the object in monochromatic colour,
the object being viewed through an aperture placed in the spectrum
produced by the apparatus. I had been working independently at
the subject at the same time, and my object was to get an image on a
screen or photographic plate rather than to use the apparatus for
visual observation. When a lens is placed behind the spectrum in
the manner described in the paper above referred to, a white image
of the prism can be obtained on a screen placed at some distance
from the lens, and the size of the image can be increased or diminished
according to the focal length of the lens, and its distance from the
spectrum. Evidently, then, if an image of a luminous object can
be cast on the surface of the prism, and a slit be placed in the
spectrum, the image of the luminous object will be seen of the
colour of the light passing through the slit. There are devices
adopted at the present time for photographing the sun with light of
various wave-lengths, but, as far as I am aware, they depend upon
moving the image of the sun across the slit of the spectroscope, the
14 Photographing with Monochromatic Rays.
plate moving across the slit in the spectrum at the requisite rate for
the various impressions made by the different parts of the sun's image
to coalesce. It had struck me some time since that the method thus
indicated nearly eleven years ago might be more convenient than
that adopted, but the time I had at my disposal prevented my carry-
ing out a continuation of my experiments. Recently I have had
occasion to take up this subject for a rather different purpose, and as
the method seems to have been untried, I give it in more detail than
I did then.
My investigation called for a determination of the proportions of
various rays emitted by the various parts of the carbon of the positive
and negative poles of an electric arc light, and for this purpose the
system of forming monochromatic images was found to be useful.
The points of the electric light EL (fig. 1) were placed so that a beam
of light passed through the slit S of the collimator on to the centre of
the collimating lens L2. A convex lens L! of shorter focus than L2 was
placed in the path of the rays, and so adjusted that a real image of the
poles was formed on L2. These passed through the lens La as nearly
parallel rays and struck upon the prism, and then passed through the
remainder of the apparatus as sketched in fig. 2, where M is the
prism, L3 a lens to bring the rays to a focus as a spectrum on ub
after passing through a camera, A. L4 is a lens, shown in the figure
connected with a camera, B, which brings the image of the prism arid
the bright image cast on it to a focus at P. By placing a slit S2 in
the spectrum, the image cast on P will be as monochromatic as the
light coming through the slit. L: should be of such a focal length
that it should be as near the slit as possible. With this" arrangement
it is very curious to watch the variations in the brightness of the arc
and of the flame which accompanies the movement of the slit through
the spectrum, and as each variation can be photographed on a Cadett
polychromatic photographic plate, we can obtain records of all that is
Determination of Coronal Light during Eclipse. 15
occurring. Further, by using strips of lenses cut out at suitable
distances from the axes (fig. 3), images of various colours can be
placed side by side upon P, since a slit may be placed in the
spectrum opposite each such strip of lens. Incidentally, I may men-
tion that investigations into the cause of the variable nature of
different flames can be carried out by this plan.
For solar work, a long collimator appears to be a necessity, but the
aperture need not be large. Suppose we determine to have an imacre
of the sun on P (fig. 2) of 2 in. diameter, the image on M need not
be more than 1 in. at most. For this purpose we must have a colli-
mator 10 ft. long. Two lenses of this focal length can be fixed one at
each end, and a slit in front of that lens which is presented to the
sun's rays. The arrangements followed will be the same as those
given for the electric light. There appears no difficulty in producing
a monochromatic image of almost any size if the collimator be suffi-
ciently long and the face of the prism sufiiciently large to take in the
whole of the image cast on it.*
I have replaced the prism by Hat refraction gratings with most
satisfactory results. The gratings I employed had about 6,000 and
12,000 lines to the inch. The images were sharply defined, but, of
course, weaker than when the prism was employed. For solar work
this should not be an objection, since there is plenty of light to work
with.
I show some pictures taken by the plan I have described. For my
purpose the images are sufiiciently sharp, although simple uncorrected
lenses have been employed.
* On the Determination of the Photometric Intensity of the
Coronal Light during the Solar Eclipse of 16th April,
1893." By Captain W. DE W. ABNEY, C.B., D.C.L., F.R.S.,
and T. E. THORPE, LL.D., F.R.S. Received April 14,—
Read April 30, 1896.
(Abstract.)
In this paper the authors give the results of the measurements of
the intensity of the light of the corona, as observed at Fundium in
Senegal, on the occasion of the solar eclipse of April 16th, 1893.
The methods employed by them were practically identical with
those used at Grenada, in the West Indies, during the eclipse
of 1886, an account of which is given in the ' Phil. Trans.,' A, 1889,
* It should be mentioned that to minimise diffraction the slits should be used
fairly wide. Hence a long collimator such as described and a good dispersion will
be necessary to obtain the best definition of the sun's image. — April 30.
16
Determination of Coronal Light during Eclipse.
p. 363, with certain slight modifications suggested by their experience
on that occasion. Two sets of observations were made : the first
with a photometer equatorially mounted, and designed to measure
the comparative brightness of the corona at different distances from
the moon's limb, and the second with an instrument arranged to
measure the total brightness of the corona, excluding as far as
possible the sky effect. In both cases the principle of photometry was
that of Bctnsen, the intensity of the coronal light being compared
with that of a standard glow-lamp, according to the method of Abney
and Festing.
The measurements with the equatorial photometer were made by
Dr. Thorpe, assisted by Mr. P. L. Gray, B.Sc., those with the second
or integrating instrument were made by Mr. Jas. Forbes, jun., assisted
by Mr. Willoughby, of H.M.S. " Alecto."
The mean of ten concordant readings with the integrating photo-
meter reduced to values of light intensity and expressed in Siemens*
units was 0'026.
The measurements with the equatorial photometer show that the
visual brightness of the corona of the 1893 eclipse varied within
comparatively wide limits, and that, at all events close to the moon's
limb, there was marked variation in local intensity. If the several
values taken in the direction of the poles and equator are grouped as
in the former paper (loc. cit.), they are found to afford a curve almost
identical in character with that already given, showing that the
diminution in intensity from the moon's limb outwards is less rapid
than accords with the law of inverse squares.
The results are as follows : —
Photometric Intensity.
Distances in solar
semi-diameters.
Observed.
Law of inverse squares.
1893.
1886.
1-6
0-060
0-066
0-066
2-0
0-048
0-053
0-042
2-4
0-038
0-043
0-029
2-8
0-030
0-034
0-022
32
0-024
0-026
0-016
3-4
0-018
0-021
0-013
These numbers would appear to show that the actual brightness of
the corona was probably not very dissimilar at the two eclipses, the
slight apparent diminution observed during the 1893 eclipse being,
The Total Eclipse of the Sun, April 16, 1893. 17
in all probability, due to the haze, or opalescence, in the air which
prevailed at the time. This haze, caused more by suspended and
finely divided solid matter than by precipitated moisture, undoubtedly
contributed to the general sky-illumination at the time of totality.
The actual gloom during this phase of the eclipse at Fundium was
certainly much less than at Grenada in 1886. It must not be for-
gotten, however, that the altitude of the sun was very different on
the two occasions. At Grenada it was only about 19° : the amount
of cloud was from seven to eight (overcast = 10) at the time of to-
tality, and much of the cloud was in the neighbourhood of the sun :
whereas at Fundium the sun's altitude was t52°, and the sky was of
a bluish- grey colour and practically free from cloud.
The effect of these different conditions in the sky in the neighbour-
hood of the disc is seen in Mr. Forbes' measurements when com-
pared with those of Lieutenant Douglas, at Grenada. The ten fairly
concordant observations at Fundium give, as already stated, an
average value of 0*026 Siemens units at 1 ft. from the screen; and
the value observed by Lieutenant Douglas, 15 seconds after totality,
with the same photometer, although with a different lamp and galva-
nometer, was 0'0197 light units.
" The Total Eclipse of the Sun, April 16, 1893. Report and
Discussion of the Observations relating to Solar Physics."
By J. NORMAN LOCKYER, C.B., F.R.S. Received April 17,
—Read April 30, 1896.
(Abstract.)
The memoir first gives reports by Mr. Fowler and Mr. Shackleton
fis to the circumstances under which photographs of the spectra of
the eclipsed sun were taken with prismatic cameras in West Africa
and Brazil respectively on April 16, 1893. These are followed by a
detailed description of the phenomena recorded, and a discussion of
the method employed in dealing with the photographs. The coronal
spectrum and the question of its possible variation, and the wave-
lengths of the lines recorded in the spectra of the chromosphere and
prominences, are next studied.
Finally, the loci of absorption in the sun's atmosphere are con-
sidered.
The inquiry into the chemical origins of the chromospheric and
prominence lines is reserved for a subsequent memoir.
The general conclusions which have been arrived at are as
follows : —
(1) With the prismatic camera, photographs may be obtained with
VOL. LX.
18 The Total Eclipse of the Sun, April 16, 1893.
short exposures, so that the phenomena can be recorded at short
intervals during the eclipse.
(2) The most intense images of the prominences are produced bj
the H and K radiations of calcium. Those depicted by the rays of
hydrogen and helium are less intense, and do not reach to so great a
height.
(3) The forms of the prominences photographed in monochromatic
light (H and K), during the eclipse of 1893, do not differ sensibly
from those photographed at the same time with the coronagraph.
(4) The undoubted spectrum of the corona in 1893 consisted of
eight rings, including that due to 1474 K. The evidence that these
belong to the corona is absolutely conclusive. It is probable that
they are only represented by feeble lines in the Fraunhofer spectrum r
if present at all.
(5) All the coronal rings recorded were most intense in the
brightest coronal regions, near the sun's equator, as depicted by the
coronagraph.
(6) The strongest coronal line, 1474 K, is not represented in the
spectrum of the chromosphere and prominences, while H and K do
not appear in the spectrum of the corona, although they are the most
intense radiations in the prominences.
(7) A comparison of the results with those obtained in previous
eclipses confirms the idea that 1474 K is brighter at the maximum
than at the minimum sun-spot period.
(8) Hydrogen rings were not photographed in the coronal spec-
trum of 1893.
(9) D3 was absent from the coronal spectrum of 1893, and reasons
are given which suggest that its recorded appearance in 1882 was
simply a photographic effect due to the unequal sensitiveness of the
isochromatic plate employed.
(10) There is distinct evidence of periodic changes of the con-
tinuous spectrum of the corona.
(11) Many lines hitherto unrecorded in the chromosphere and
prominences were photographed by the prismatic cameras.
(12) The preliminary investigation of the chemical origins of the
chromosphere and prominence lines enables us to state generally that
the chief lines are due to calcium, hydrogen, helium, strontium, iron,
magnesium, manganese, barium, chromium, and aluminium. None
of the lines appear to be due to nickel, cobalt, cadmium, tin, zinc,
silicon, or carbon.
(13) The spectra of the chromosphere and prominences become
more complex as the photosphere is approached.
(14) In passing from the chromosphere to the prominences, some
lines become relatively brighter but others dimmer. The same line
sometimes behaves differently in this respect in different prominences.
On some Paleolithic Implements found in Somaliland. 19
(15) The prominences must be fed from the outer parts of the
solar atmosphere, since their spectra show lines which are absent
from the spectrum of the chromosphere.
(16) The absence of the Fraunhofer lines from the integrated
spectra of the solar surroundings and uneclipsed photosphere shortly
after totality need not necessarily imply the existence of a reversing
layer.
(17) The spectrum of the base of the sun's atmosphere, as recorded
by the prismatic camera, contains only a small number of lines as
compared with the Fraunhofer spectrum. Some of the strongest
bright lines in the spectrum of the chromosphere are not represented
by dark lines in the Fraunhofer spectrum, and some of the most
intense Fraunhofer lines were not seen bright in the spectrum of the
chromosphere. The so-called " reversing layer " is therefore incom-
petent to produce the Fraunhofer spectrum by its absorption.
(18) Some of the Fraunhofer lines are produced by absorption
taking place in the chromosphere, while others are produced by
absorption at higher levels.
(19) The eclipse work strengthens the view that chemical sub-
stances are dissociated at solar temperatures.
" On some Palaeolithic Implements found in Somaliland by
Mr. H. W. Seton-Karr." By Sir JOHN EVANS, K.C.B.,
D.C.L., Treas. and V.P.R.S. Received April 27,— Read
April 30, 1896.
Although some account of his recent discoveries in Somaliland
(tropical Africa) has already been given to the Anthropological
Institute by Mr. Seton-Karr, and has been published in their Journal,*
these discoveries seem to me to have so wide an interest, and such an
important bearing on the question of the originaJ home of the human
race, that I venture to call the attention of this Society to them.
In the course of more than one visit to Somaliland for sporting
purposes, Mr. Seton-Karr noticed, and brought home for examination,
a number of worked flints, mostly of no great size, which he laid
before the Anthropological Section of the British Association, at the
meeting last year at Ipswich. f Although many of these specimens
were broad flat flakes trimmed along the edges so as to be of the
"le Moustier type" of M. Gabriel de Mortillet, and although the
general fades of the collection was suggestive of the implements
being of palaeolithic age, they did not afford sufficient evidence to
enable a satisfactory judgment to be formed whether they undoubtedly
belonged to the palaeolithic period.
* Vol. 25, p. 271.
f Eeport, 1895, p. 824.
C 2
20 On some Palaeolithic Implements found in Somaliland.
Before returning to Somaliland, Mr. Seton-Karr visited my collec-
tions, and studied the various forms of implements found in the
river-gravels and Pleistocene deposits in different parts of the world,
so as to become familiar with their leading features ; and on revisiting
Somaliland during the past winter, he was fortunate enough to meet
with a large number of specimens in form absolutely identical with
some from the valley of the Somme and other places which he had
seen in my collection.
Of this identity in form there can be no doubt, and though at
present no fossil mammalian or other remains have been found with
the implements, we need not hesitate in claiming them as palaeolithic.
They seem to be scattered all over the country, and to have been
washed out of sandy or loamy deposits by the action of rain, or, in
some instances, to have been laid bare by the wind. They appear
also to occur most frequently in the neighbourhood of existing water-
courses, which is at all events suggestive of the beds in which they
occur having been in some manner the result of river-action. It
is, however, at present premature to enlarge on the circumstances of
their discovery. Their great interest consists in the identity of their
forms with those of the implements found in the Pleistocene deposits
of North Western Europe and elsewhere. Any one comparing the
implements from such widely separated localities, the one with the
other, must feel that if they have not been actually made by the same
race of men, there must have been some contact of the closest kind
between the races who manufactured implements of such identical
forms. Those from Somaliland occur in both flint (much whitened
and decomposed by exposure) and in quartzite, but the implements
made from the two materials are almost indistinguishable in form.
Those of lanceolate shape are most abundant, but the usual ovate and
other forms are present in considerable numbers.
Turning westward from Somaliland we meet with flint implements
of the same character found by Professor Flinders Petrie afc a height
of many hundred feet above the valley of the Nile. A few have
been discovered in Northern Africa, they recur in the valley of the
Manzanares in Spain, in some districts in Central Italy, and abound
in the river-valleys of France and England. Turning eastward we
encounter implements of analogous forms, one found by M. Chantre
in the valley of the Euphrates, and many made %of quartzite in the
laterite deposits of India ; while in Southern Africa almost similar
types occur, though their age is somewhat uncertain.
That the cradle of the human family must have been situated in
some part of the world where the climate was genial, and the means
of subsistence readily obtained, seems almost self-evident ; and that
these discoveries in Somaliland may serve to elucidate the course by
which human civilisation, such as it was, if not indeed the human
On the Liquation of certain Alloys of Gold. 21
race, proceeded westward from its early home in the east is a fair
subject for speculation. But, under any circumstances, this dis-
covery aids in bridging over the interval between palaeolithic man
in Britain and in India, and adds another link to the chain of
evidence by which the original cradle of the human family may
eventually be identified, and tends to prove the unity of race between
the inhabitants of Asia, Africa, and Europe, in Palaeolithic times.
" On the Liquation of certain Alloys of Gold." By EDWARD
MATTHEY, F.S.A., F.C.S., Assoc. R.S.M. Communicated by
Sir G. G. STOKES, Bart., F.R.S. Received April 14,—
Read May 7, 1896.
The molecular distribution of the metals in alloys of gold and of
metals of the platinum group has been described by me at some
length, in a series of papers which have already been published by the
Royal Society.* New interest in the subject has, however, arisen in
connexion with the extraordinary development in various parts of the
world especially in South Africa, of certain processes which are now
employed for extracting gold from its ores. Their use has been
attended with the introduction into this country of a series of alloys
of gold and the base metals which have hitherto rarely been met
with in metallurgical industry. The base metals associated with the
gold in these cases are usually the very ordinary ones lead and zinc,
but their presence in the gold has given rise to unexpected difficul-
ties, as the distribution of the precious metal in the ingots which
reach this country is so peculiar, that it is not possible to estimate
the value of the ingots by taking the pieces of metal required for
the assay, by any of the well-known methods now in use.
The grouping of the metal in these ingots presents much scientific
as well as industrial interest, and the following is a brief state-
ment of the facts which have been observed. r
A. An ingot of gold weighing 3'545 kilograms was assayed with a
view to subjecting it to the ordinary operation of refining. A piece
of metal was, therefore, cut from the base of the ingot at the point
marked A, and the following are the results of four assays made
on this piece of metal : —
Gold 1 665-8
2 663-6
3 662-4
4 658-0
Average 662'45
* ' Phil. Trans.,' A, vol. 183; p. 629, 1892. ' Boy. Soc. Proc.,' vol. 47, p. 180, 1890.
22 Mr. E. Matt hey.
There was also 0'061 part of silver present in 1000 parts of the
mass, the remainder being base alloy.
Another set of assays from the same ingot, but from the opposite
end, at the point marked B, gave the following results : —
1 429-9
2 459-5
3 439-0
4 . 429-0 Silver . 0'071
Average 439'35
The difference in the amount of gold between the two opposite
ends of the ingot was, therefore, no less than 223*10 parts in 1000.
The base metal present was proved by analysis to be chiefly zinc,
Jead, and copper, as the following results will show on metal taken
by a " dip," i.e., from the molten metal : —
Zinc 15-0
Lead 7'0
Copper 6'5
Iron 2-2
Mckel 2-0
Silver 7'0
Gold (by difference) 60%3
100-0
B. Another ingot of alloyed gold weighing 12 223 kilograms gave
at different parts of the ingot the following results by assay : —
Four assays on a piece of metal cut at a — top of ingot —
Gold. Silver.
1 664-0 0-090
2 662-5 0091
3 465-0 0-076
4 . 661-5 0-091
On the Liquation of certain Alloys of Gold. 23
Three assays at b — bottom of ingot^—
Gold. Silver.
1 332-5 0181
2 652-0 0-095
3 410-5 0-057
And seven assays were made from a " dip," viz. —
Gold. Silver.
1 622-0
2 574-4 0-072
3 653-5 0-011
4 623-2
5 580-0 0-138
6 603-3 —
7 . 562-3 —
Average of the whole number
of the assays made .... 576*2 0'090
It became evident, therefore, that the only method of determining
the true quality of this ingot consisted in actually separating the
gold and silver in mass, and this was effected by dissolving in nitro-
hydrochloric acid, the silver being recovered as chloride and reduced
to metallic silver, and the gold precipitated by iron chloride as pure
metallic gold.
The result of this operation yielded
Gold 7-504 kilograms.
Silver 0-928
which showed that the standard fineness of the ingot was
Gold 614-0
Silver 75'8
and its true value £1,028 ; while the value, as calculated from the
average of the assays previously made,
Gold 576
Silv-r 0-090
would have been only £965.
Analysis proved that the metals present other than gold were
as follows : —
24 Mr. E. Matthey.
Silver 8-1
Lead 16-4
Zinc 9-5
Copper 4*0
Iron 0-3
Gold (by difference) .. 61-7
100-0
The cause of the differences revealed by assays made from metal
cut from various parts of the ingot was clearly due to liquation. ;
but previous experience failed to afford any guide to the probable
distribution of the precious and base metals in the ingot.
C. Another instance, and on a mu.cn larger quantity of gold alloy
than the two former examples, was afforded by an ingot weighing
39*625 kilograms, which showed such great variation in its gold con-
tents at various points that the ingot was re-melted and cast into
two separate ingots, from which portions of metal were removed for
assay by drilling.
by boring 709-0
by boring ror-s
All these results fare the averages of assays made in triplicate,
and a " dip " assay from the melted metal showed that it contained
701 parts of gold in 1000.
The analysis of this metal gave —
Zinc ,. 7-1
Lead 4'9
Copper 4'8
Iron 1'4
Silver 9-2
Gold (by difference). . 72'6
100-0
As in the former case, the gold and silver present were isolated
in mass, and the actual yield of fine gold and silver so obtained was
as follows : —
On the Liquation of certain Alloys of Gold.
25
Gold 27-914 kilograms.
Silver 3-568
which proved that the actual gold standard of the ingot was 703'9.
The base metal in two similar ingots was found by analysis to be
composed as follows : —
(492 ) (494.)
Silver 8'9 8'0
Lead 9'0 77
Zinc 4-8 8-5
Copper 5-2 3'2
Iron 0-4 V6
Nickel 0-8 1-8
Gold (by difference).. 7O9 69'2
100-0 100-0
from which it would appear that the presence of one or both of the
metals — zinc and lead — bears in some degree upon these variations
in quality — it being well known that gold will alloy, and be constant
in quality, with either silver or copper or with both in almost any
proportions.
Advancing progressively, I now cite an instance of irregular dis-
tribution in a much baser alloy of gold.
An ingot of base gold alloy (P. 13) weighing 9'570 kilograms.
Determinations from the top of this ingot gave results
Point a —
Gold.
265-0
378-4
383-0
Silver.
213
From the bottom, point 6 —
527-2
560-0 66
545-5
From a " dip " taken from the fused alloy -
561-0
618-5 75
683-0
differences which are too significant to need comment.
26
Mr. E. Matthey.
In order to ascertain the effect exerted by these two metals — lead
and zinc — in conjunction with gold, I prepared an alloy of 700 parts
pure gold and 300 parts pure lead, and after mixing and casting into
an open mould I cast the melted alloy into a spherical mould 2 in.
in diameter, made of cast iron. Determinations made from different
parts, after cutting the sphere into two halves, gave the following
results, the assays being made in triplicate upon each portion of
metal removed.
(The weight of this sphere was a little over 2 kilograms.)
FIG. 1.
The result shows a decided tendency of the gold to liquate to the
centre of the mass.
In the next experiment gold was alloyed with lead and zinc in the
following proportions : —
Gold 75 parts.
Lead 15 „
Zinc 10 „
adding the zinc when the alloy of the first two metals was thoroughly
fluid, and after casting this into an open mould, the alloy was
remelted and cast into the 2-in. spherical mould before mentioned.
This alloy was extremely hard and very brittle. Portions removed
from the different parts of the sphere, after cutting it across, gave
the following results : —
FIG. 2.
On the Liquation of certain Alloys of Gold. 27
There is evidence of re- arrangement by liquation in this case
which sends gold to the centre, but the result is complicated, as
gravity appears also to send gold to the lower portion of the spherical
mass.
The foregoing mixture (No. 2) of
Gold 75 parts.
Lead 15 „
Zinc 10 „
was now further alloyed by the addition of 5 per cent, of pure copper
and cast into a sphere which was very hard and brittle, and weighed
about 2 kilograms.
The following are the results at the points shown : —
FIQ. 3.
Here again, gravity appears to send gold to the lower portion of the
sphere.
The question arises, does the silver play any part in the distribu-
tion of the baser metals, lead and zinc ?
I therefore melted sphere No. 3 with 10 per cent, of silver, so that
there were present : —
Gold 63-4 (by difference)
Silver 7'8
Copper 5'1
Zinc 8'8
Lead 14-5
Iron 0'4
100-0
and cast into an open mould, and subsequently into the spherical
mould. The following were the results obtained of fine gold at the
points indicated : —
28
Mr. E. Matthey
FIG. 4.
This sphere seems constant all over.
In order to see what was the effect with pure gold alloyed with
metallic zinc only, I cast an alloy of fine gold with 5 per cent, of
zinc into a 3-in. spherical mould. The weight of the sphere was
3-438 kilograms.
The results were as follows : —
Fia. 5.
(Five per cent. zinc.
A slight but decided tendency of liquation of gold towards the
centre.
The same alloy, containing 95 per cent, of gold and 5 per cent, of
zinc, was then alloyed with a further 5 per cent, of zinc and cast
into the same sphere. This weighed 4*218 kilograms. The results
were as follows : —
On the Liquation of certain Alloys of Gold.
FIG. 6.
638-8
(Ten per cent, zinc.)
Feeling a little diffident about these results, 1 recast the foregoing
alloy of gold with 10 per cent, of zinc, into the same mould.
The results were as follows : —
FIG. 7.
(Ten per cent, zinc.)
This shows that there is stiii a tendency in this gold alloy with
10 per cent, of zinc to become enriched towards the centre.
This 10 per cent, alloy was then alloyed with a further 5 per cent,
of zinc and cast into the same spherical mould. The weight of this
sphere was 4'021 kilograms. The results were : —
30
Mr. E. Matthey.
TIG-. 8.
(Fifteen per cent, zinc.)
It is abundantly evident therefore, that zinc alone will not account
for the differences in the ingots of impure gold ; and the question
arose, will the presence of a definite amount of silver in any way
prevent the irregularity in composition ?
To test this I alloyed the gold, which contained 15 per cent, of zinc
so that it might also contain 7'5 per cent, of silver.
This was cast into the 3-in. sphere and weighed 3'934 kilograms,
and assays made on portions of metal cut from it gave the following
results : —
FIG. 9.
dOi-4
(Fifteen per cent, zinc.)
It was intended to contain —
Zinc 15-0
Silver 7'5
Gold . 77-5
100-0
On the Liquation of certain A Hoys of Gold.
31
the extra richness of the gold over 77'5 being due to the volatilisa-
tion of the zinc. This experiment appears to confirm, that on pp. 27,
28 (see results of fig. 4).
The foregoing experiments show that lead is far more effective as a
cause of liquation than zinc, and the question arises, do zinc and lead
separate into distinct layers by gravity when they are simultaneously
present in a mass of gold, as they are known to do when they (lead
and zinc) are melted together and allowed to solidify slowly. If they
do separate, are they respectively associated with precious metal ?
Professor Roberts-Austen has given us a method of investigating
such a problem. He has shown that it is easy to place a suitably
protected thermo- junction in a mass of cooling alloy, and obtain by
photography a record of the cooling of the mass,* a method which
was employed by me for determining the temperatures at which the
metals arsenic and antimony separate from bismuth. Applying
this method to a mass weighing 44 grams of an alloy containing : —
Gold , . . . 75-0
Lead 15-0
Zinc lO'O
The following curve, No. I, is an autographic record of its solidifi-
cation : —
CTTEVE No. I.
Cooling curve of Au,Ca,Zn,Pb.
73,° C.
655° C. ("main point)
407° C.
*r°C.
206° C.
Time .
* See ' Boy. Soc. Proc./ vol. 52, p. 467.
32
Mr. E. Matthey.
From this it will be evident, from the horizontal position (6) (of
the curve No. I) that the mass solidifies as a whole at 635° C. ; bat
there is a second break c in the curve at a temperature of 407° C. ;
and there is yet a third break at d, 247° C. These latter points
evidently are connected with the solidifying points of lead and zinc,
but it is probable that these metals are, in solidifying, associated with
some gold.
The second curve, No. II, represents the cooling of the same mass
of gold with 10 per cent, of silver added. It will be seen that the
metal has still one main solidifying point 6, at 645° C. The lower
point (c) of the former curve is entirely absent, but there is an
indication of the lead point at 206°. The results clearly indicate
that silver is a solvent common to both zinc and lead, which are not,
as in the previous case (Curve I) free to separate from each other.
Such a mass should be fairly uniform in composition, and assays from
different portions of it proved it to be so.
CURVE No. II.
Time.
Cooling of alloy of Au,Cu,Zn,Pb, (&'S$gA/') C.J.*/4°C.
The latter curve (II) seems to change its direction at 767°, which
is above the main solidifying point of the mass, and it remains to be
seen whether this is of any significance.
The inspection of the curves so obtained at once led me to infer
that silver mast be a solvent for zinc and lead when these are present
On the Liquation of certain Alloys of Gold.
33
in gold, and with the clear indication thus afforded I proceeded to
make the following experiments : —
The alloy-
Zinc 11-0
Silver 7-5
Gold 81-5
100-0
and weighing 5'680 kilograms, was now alloyed by the addition of
lead to produce a similar metal to P. 13 (see p. 25), say : —
Zinc . .
Lead. .
Silver
Gold..
10
20
7
63
100
and this was cast into two spheres, a 2-in. sphere and a 3-in.
sphere.
This alloy was so hard and brittle that I was compelled to cut
these spheres into two by sawing them. When so cut asunder it was
evident that the upper portions of both these spheres had a marked
white appearance, as compared with the lower portions, which
possessed the yellow colour of gold. The 3-in. sphere weighed
3'484 kilograms. Portions removed from these two spheres at the
points indicated showed the following results : —
FIG. 10.
And those from the 2-in. sphere, weighing 0'880 kilogram —
VOL. LX.
34
On the Liquation of certain Alloys of Gold.
Fia. 11.
Very marked separation takes place in both instances, the differ-
ences at various points of the sphere being very remarkable and
forcibly illustrating the difficulties to which reference is made at the
commencement of this paper.
As, however, it appears, that when a certain amount of silver is
present, the irregularity in composition disappears, I alloyed this
mixture of —
Zinc . .
Lead. .
Silver
Gold.,
10
20
7
63
with more silver, so that it contained 15 per cent, of silver (nearly
half the united amounts of zinc and lead present in the alloy).
This, cast into the 3-in. spherical mould, showed the following
results at the points indicated. In appearance, the metal, when sawn
in two, was homogeneous. The weight of the sphere was 3'459 kilo-
grams.
FIG. 12.
Occurrence of the Element Gallium in Clay-Ironstone. 35
There is still evidence of liquation of gold towards the centre, but
comparison of fig. 12 with those which immediately precede it' will
show how greatly the arrangement of the alloy has been modified by
the presence of the additional 8 per cent, of silver. The proportion
of silver in this alloy was proved by assay to be 15'5 per cent.
As there was still evidence of liquation, the metal was cast with
.still more silver, making 20 per cent, of silver in all. The alloy,
when cast into a mould, proved to be almost uniform in composition]
the difference between the centre and the extreme portions being very
slight.
Liquation had practically ceased, a fact which proves incontest-
ably that silver is the solvent for the base metals, zinc and lead,
when they are alloyed with gold.
Conclusions.— (1) Alloys of gold with base metals, notably with
lead and zinc, now largely often met with in industry, have
the gold concentrated towards the centre and lower portions, which
renders it impossible to ascertain their true value with even an
approximation to accuracy.
(2) When silver is also present these irregularities are greatly
modified.
The method of obtaining "cooling-curves" of the alloys shows
that the freezing points are very different when silver is present and
when it is absent from the alloy.
(3) This fact naturally leads to the belief that if the base metal
present does not exceed 30 per cent., silver will dissolve it and form
a uniform alloy with gold.
(4) This conclusion is sustained by the experiments illustrated by
figs. 9, 10, 11, 12, which, in fact, gradually lead up to it, and enable
a question of much interest to be solved.
41 Ori the Occurrence of the Element Gallium in the Clay-
Ironstone of the Cleveland District of Yorkshire. Prelimi-
nary Notice." By W. N. HARTLEY, F.R.S., Professor of
Chemistry, and HUGH RAM AGE, A.R.C.S.I., F.I.C., Assistant
Chemist in the Royal College of Science, Dublin. Received
April 13,— Read May 7, 1896.
In the course of an investigation of flame spectra at high tempera-
tures (« Phil. Trans.,' A, vol. 185, pp. 1029—1091 (1894) ) extended to
the basic Bessemer process, the authors were occupied last July and
August in observing the flames from the converters at the North
Eastern Steel Company's Works, at. Middlesbrough-on-Tees. A
large number of photographs were taken in series during the pro-
gress of the "blow," and also of the "after blow," but these will
D 2
36 Occurrence of the Element Gallium in Clay-Ironstone.
form the subject of another communication dealing with the chem-
istry of the process.
Some of the photographs were remarkably fine in definition, and
they extended from the less refrangible limit of the red rays to the
ultra-violet, about wave-length 3240.
It may be mentioned here, however, that every line and band in
the different spectra was identified. Some of the photographs
afforded evidence of very unusual constituents in the mixture of
gases and vapours, which by their combustion and incandescence
give the Bessemer flame. The identity of these could have been
established only by means of very complete investigation of oxy-
hydro°"en blowpipe spectra. Apart from all technical considera-
tions which were kept in view, and of such purely scientific questions
as were involved in similar previous researches carried out by one of
us, the examination of these spectra was of great 'interest, more
especially because of the proof of the rare element, gallium, being-
present in the Bessemer metal, and in the roasted ore from which
it was extracted. It was shown by very careful analyses that the
gallium was concentrated in the iron, but all details of the operations
involved in its separation and of the quantitative determinations are-
reserved for a future communication.
The evidence of the existence of gallium in the ore and in the
metal rests on the measurements of the wave-lengths of the lines in
a large number of photographed spectra and upon the relative
strengths of the lines in the different materials examined and in the
precipitates obtained therefrom.
The following examples show the nature of this evidence : — •
1. Evidence from the Bessemer Flame Spectra.
Seventy-six of the photographed spectra of the Bessemer flame
contain a strong line with wave-length about 4171'5, which does not
appear to be related to any other line in these spectra, and belongs,
therefore, to some other element than those otherwise identified.
2. Evidence from the Spectrum of the " Mixer Metal " and of the
different substances separated by its Chemical Treatment.
The " mixer metal " heated in the oxy-hydrogen flame gives a
spectrum of iron with a strong line having a wave-length of 417T6.
The residue left after dissolving the iron by boiling with hydro-
chloric acid also gives this line 4171*6 very strongly.
• Precipitates obtained by boiling the solution of the iron with am-
monium acetate give the line 41 71 '6 and also a weaker line, wave-
length 40327.
Electromotive Properties of Electrical Organ of Malapterurus. 37
The latter line is seen only in the absence of manganese, as it very
nearly coincides with one of the group of strong manganese lines ; it
is, therefore, obscured in the spectra of the Bessemer flame and of
the crude iron. ^
The oxide of gallium was separated as far as possible from all other
substances and heated in the oxy-hydrogen flame and the character-
istic spectrum was then photographed from this oxide.
3. Evidence from the Roasted Ore, and substances separated therefrom.
The roasted Cleveland ore was heated alone for thirty-five minutes
in the oxy-hydrogen flame, it gave only a very faint indication of one
line in the spectrum of gallium. The solution extracted from the
ore by digesting it with warm dilute hydrochloric acid of double
normal strength, when boiled with ammonium acetate gave a precipi-
tate, the spectrum of which contained the line 4171'6 fairly strong.
The silicious residue insoluble in strong hydrochloric acid, when
decomposed by fusion with caustic potash and subsequent boiling
with water, after concentration of the solution so as to retain the
gallium, gave a spectrum containing both lines, 4171/6 and 40327.
All other elements had been removed.
The wave-lengths given are on Rowland's scale. The lines were
measured on many plates and also repeatedly on the same plate, the
results being the same in each case.
Electromotive Properties of the Electrical Organ of
Malapterurus electricm" By FRANCIS GOTCH, M.A. (Oxon.),
F.R.S., and G. J. BuRCH, M.A. (Oxon.). Received April
2,— Read May 7, 1896.
(Abstract.)
The experiments were made upon six specimens of Malapterurus
electricus, 12 to 15 cm. in length, brought from the River Senegal by
Mr. A. Ridyard (ss. "Niger"), and generously placed at the. dis-
posal of the authors by the Liverpool Corporation Museum Committee,
to whom and to Dr. Forbes, the Director of the Museum, the authors
desire to express their thanks.
Three of the specimens were killed, in order to carry out experi-
ments upon the isolated organ. The instrumental methods employed
by the authors for determining for the first time the characters and
time relations of the activity of the organ response were chiefly the
following : —
(a.) The record of the frog nerve muscle galvanoscope.
(&.) The galvanometer connected with a suitable .rheotome.
28 Messrs. F. Gotch and G. J. Burch.
(c.) The capillary electrometer, a large number (about 250) photo-
graphic records being taken of the movements of the meniscus.
Facsimile reproductions of typical records are given in the fuller
communication. The electrometer was used either shunted by a
resistance of from 80 to 100 ohms, or in connection with the outer
plates of a special condenser, the inner plates of which were con-
nected with the fish or its electrical organ.
The organ responded to mechanical or electrical excitation of its
nerves after removal from the fish, the response being unaffected by
1 per cent curare, or 1 per cent, atropine solution. No response
could be evoked by such chemical agents as sodium chloride, gly-
cerine, or weak acid, when applied either to the organ or its efferent
nerve.
The conclusions drawn by the authors from the experiments on the
isolated organ and on the entire uninjured fish may be summarised as
follows : —
(1) The isolated organ responds to electrical excitation of its nerves
by monophasic electromotive changes, indicated by electrical currents-
which traverse the tissue from the head to the tail end ; this response
commences from 0'0035" at 30° C. to 0'009" at 5° C. after excitation,
the period of delay for any given temperature being tolerably constant,
(2) The response occasionally consists of a single such monophasic
electromotive change (shock) developed with great suddenness, and
subsiding completely in from 0*002" to 0'005", according to the tem-
perature ; in the vast majority of cases the response is multiple, and
consists of a series of such changes (shocks) recurring at perfectly
regular intervals, from two to thirty times (peripheral organ rhythm) ;
the interval between the successive changes varies from 0'004" at
30° C. to O'Ol" at 5° C., but is perfectly uniform at any given tempera-
ture throughout the series.
(3) Such a single or multiple response (in the great majority of
cases the latter) can also be evoked by the direct passage of an induced
current through the organ and its contained nerves, in either direc-
tion heterodromous (i.e., opposite in direction to the current of the
response) or homodromous.
(4) The time relations of the response are almost identical whether
this is evoked by nerve-trunk (indirect) stimulation, or by the passage
of the heterodromous induced current.
(5) There is no evidence that the electrical plate substance can be
excited by the induced current apart from its nerves, i.e., it does not
possess independent excitability.
(6) The organ and its contained nerves respond far more easily to
the heterodromous than to the homodromous induced current, and the
period of delay in the case of the latter response is appreciably
lengthened.
Electromotive Properties of Electrical Organ of Malapterurus. 39
(7) The peripheral organ rhythm (multiple response) varies from
about 100 per second at 5° C. to about 280 per second at 35° C.
(8) One causative factor in the production of the peripheral
rhythm is the susceptibility of the excitable tissue to respond to the
current set up by its own activity (self excitation).
(9) In the uninjured fish mechanical or electrical excitation of the
surface of the skin beyond the limits of the organ evokes a reflex
response with a long delay (0'03" to 0'3") ; this reflex response con-
sists of groups of shocks, each group showing the peripheral organ
rhythm, but separated from its neighbour by a considerable interval
of time (reflex or central rhythm).
(10) In the uninjured fish electrical excitation of the skin over
the organ evokes a response which may consist of a direct peripheral
organ effect followed by such a reflex effect.
(11) The minimal total reflex delay at 20° C. is 0'023", giving a
central excitatory time of about O'Ol".
(12) The reflex or central rhythm in our specimens showed a
maximum rate of 12 per second and an average rate of from 3 to
4 per second.
(13) The number of separate groups in the reflex response recurring
at the intervals mentioned in the preceding paragraph was in our fish
limited to from 2 to 5.
(14) The E.M.F. of each single change in the organ response
depends upon the number of effective plates with their nerves, and in
10 cm. of excited organ cannot possibly be less than 75 volts,
and is probably much nearer 150 volts. As in our specimens the
number of plates in series in 1 cm. of organ was 180, this gives a
minimal possible E.M.F. of 0'04 volt, and a probable E.M.F. of
0*07 volt for each plate.
The authors further conclude that, since each lateral half of
the organ is innervated by the axis cylinder branches of one efferent
nerve cell, and has no independent excitability, the specific characters
of the reflex response of the organ express far more closely than
those of muscle the changes in central nerve activity, and are pre-
sumably those of the activity of a single efferent nerve cell.
The single efferent nerve cell, the activity of which is thus for the
first time ascertained, shows —
(a.) A minimum period of delay of O'OOS" to O'Ol".
(6.) A maximum rate of discharge of 12 per second.
(c.) An average rate of discharge of 3 to 4 per second.
(d.) A susceptibility to fatigue showing itself in the discharge
failing after it had recurred from two to five times at the above
rates.
40 Dr. T. W. Eden.
4i The Occurrence of nutritive Fat in the Human .Placenta. A
Preliminary Communication." By THOMAS WATTS EDEN,
M.D., M.R.C.P. Communicated by Dr. PYE SMITH, F.R.S.
Received April 23,— Read May 7, 1896.
(From the Laboratories of the Conjoint Board of the Royal Colleges of Physicians
(Lond.) and Surgeons (Eng.)).
Recently, while examining specimens of ripe placentae for fatty
degeneration, I was struck by the regularity of the occurrence of fat
in this structure, and especially by the nature and extent of its dis-
tribution. I was then led to examine a series of specimens taken at
different periods of gestation, with the result that a free deposit of
fat was found in ten different placentae, all of which I believe to be
non-pathological, and ranging practically through, all periods of
gestation, from the sixth week up to term.
The method employed for the demonstration of this fat, was to take
slices from different parts of the placenta, and harden them for a few
days in Muller's fluid; then to transfer thin strips, not exceeding one-
third of an inch in thickness, to Marchi's fluid (1 per cent, solution
of osmic acid 1 part, Muller's fluid 2 parts) for a week. The pieces
were then embedded in paraffin, cut with a rocking microtome, and
stained lightly with saffranine, eosine, or logwood and cosine, pr
mounted unstained. By this process the fat is completely blackened,
while the other tissues retain their normal staining reactions, so
that the outlines of the fat-containing cells can be distinctly made
out.
By this method I have been able to demonstrate the constant
occurrence of fat in certain well-defined regions of the human
placenta.
In the young human placenta, the epithelial covering of the villi
consists of two layers, a superficial, nucleated, plasmodial layer, and
a deep cellular layer. In a six weeks' ovum I found fat in the form
of minute droplets in both these layers, but much more abundantly in
the former than in the latter. These fat droplets show comparatively
little variation in size, and they remain discrete, showing little or no
tendency to form larger droplets by fusion ; they are confined to the
perinuclear protoplasm, and are never found in the nuclei, which
remain unaltered in number, form, and arrangement. The stroma of
these villi contains here and there a trace of fat, but it is apparently
healthy, and is furnished with well-formed wide capillaries filled
with blood. The villi are, in fact, to all appearance healthy. Every
villus does not show this deposit of fat, but it is present in very large
numbers of them ; in every field of the microscope several villi
•
The Occurrence of nutritive Fat in the Human Placenta. 41
containing fat may be found. The amount of fat also varies con-
siderably.
In a young ovum the plasmodial layer of the villi shows great pro-
liferative activity ; it throws out numerous club-shaped processes or
buds, which represent the first stage in the development of new
villi. These buds very frequently contain large numbers of minute
fat droplets. I believe that this is a point of very great importance,
showing, as it does, that the deposit of fat occurs in actively growing
tissues of undoubted vitality.
]n the ripe placenta the proliferation of the plasmodial layer has
ceased, and degenerative changes are present in scattered regions.
But, of course, the great majority of the villi retain their vitality,
and in these villi a free deposit of fat is present, showing the same
distribution and characters as in the young placenta.
I have also found a similar deposit of fat in the serotina. The six
weeks' ovum, above referred to, showed very many decidual cells
containing minute, discrete droplets of fat in the perinuclear proto-
plasm. A placenta of the sixth month also showed an abundant fat
deposit in' the same region. At term, the serotina shows many
degenerative changes, and although it contains fat, it may well be
doubted whether, at this period, this is a physiological deposit.
The placenta, indeed, appears to be a storehouse of nutritive fat,
just as is the liver. This appears to throw some light on what has
long been one of the problems of foetal physiology, viz., the source
frcm which the foetus obtains its supplies of fat. Diffusible substances
such as sugar, salts, peptones, &c., were supposed to pass by osmosis
from the maternal blood in the inter- villous spaces, to the foetal blood
in the villi. But this could not be assumed of indiffusible substances
such as fat. The truth would seem to be that fat is deposited from
the maternal blood in the epithelium of the villi, and stored up there
by the foetal tissues for their use. No great accumulation of fat
occurs, as it appears to be from time to time absorbed and disposed
of by the foetal circulation. It is, however, not altogether clear how
si deposit of fat in the decidual cells can be made available for the
purposes of foetal nutrition.
Since finding this fat deposit in the human placenta, I have begun
a series of comparative observations upon the placentae of other
mammals. Up to the time of writing, I have examined two rabbits'
placentae, one from an early, and the other from a late, period of
gestation. In both there was a marked deposit of fat, chiefly in the
superficial glandular layer of the maternal placenta, but also, though
to a less extent, in the processes of the chorionic mesoblast, which
form the homologues of the villi of the human placenta.
The process appears to correspond closely to that observed by
Mr. George Brook, in the transmission of fat from the yolk to
42 Mr. E. A. Mincliin. Note on the Larva and the
the segmenting germinal area, by the parablast of mesoblastic
ova.*
I was under the impression when these observations were made,
that fat had never been found, in this form, in the placenta before.
I find that I am to some extent anticipated by a paper in the
* Archiv fiir Gynaekologie,' February, 1896. t One of the authors
(Aschoff) wished to examine a malignant uterine growth, which he
believed to be of the nature of Deciduoma malignum. Before doing
so, he examined several specimens of young human ova, in Older, as
he says, to learn something of the struciure of growing chorionic
villi. Some of the specimens he hardened in Memming's solution,
and in all of these he found fat in the plasmodial layer of the villi.
Aschoffs description of the fat deposit agrees very closely with that
already given of my own specimen. " An den Flemmingschen
Praparaten ist das Syncytium dadurch ausgezeichnet, dass es in
seiner Bandzone eine dichte Anhaufung feinster Fetttrb'pfchen tragt.
Dieselbe sind bald sehr fein, bald grobkornig, aber in den betreffenden
Abschnitten des Syncytiums stets von gleicher Grosse Die
Fetttropfcben iiberall sich finden, wo Chorionepithelzellen, in
directesten Stoffwechselaustausch mit den Intervillosenraumen
treten" (p. 531).
Aschoff scarcely appreciates the physiological importance of the
observation, but there can be no doubt that his observations and my
own are mutually confirmatory.
*' Note on the Larva and the Postlarval Development of
Leucosolenia vanabilis, H. sp., with Remarks on the Develop-
ment of other AsconidsB." By E. A. MINCHIN, M.A., Fellow
of Merton College, Oxford. Communicated by Professor
E. RAY LANKESTER, F.R.8. Received April 25,— Read
May 21, 1896.
Introductory Remarks.
Through the kind hospitality of Professor de Lacaze-Duthiers, I
was able to spend the spring and summer of last year at the marine
laboratories of Banyuls-sur-Mer and Roscoff, where I was chiefly
engaged in studying the embryology of the Asqons. In Banyuls I
obtained the larvae of Leucosolenia cerebrum, H. sp., in June, and of
L. reticulum, O.S. sp., in July. In Roscoff I found the larvae of L.
varialilis, H. sp., all through August and the early part of September,
* " Formation of the Germinal Layers in Teleostei," ' Eoy. Soc. Edin. Trans./
1896.
f " Ueber bosartige Tumoren der Chorionzotten," Apfelstedt und Aschoff.
Postlarval Development of Leucosolenia variabilis, H. sp. 43
and of L. coriacea, Mont, sp., in September. Owing to the inexperi-
ence with which I approached the difficult task of rearing these
larvae, my results are not so complete in all details as T could wish,
but in the case of L. variaUlis I was able to obtain a more or less
perfect developmental series, and in the other three species I was able
to make out satisfactorily the main points in (he metamorphosis,
especially the important question of the relation between the cell-
layers of the larva and those of the adult. I hope to bring my inves-
tigations to completion during the present year, but, in the meantime,
the results obtained seemed to me of sufficient importance to form
the subject of a preliminary note. The material which I collected
and preserved was further studied at Munich, in the laboratory of
Professor Richard Hertwig, to whom I am indebted for much kind
help and advice, as well as hospitality.
The Development of Leucosolenia variabilis (Ascandra variabilis, H.).
The larvae of L. variabilis are of the so-called amphiblastula type,
but in many respects more primitive than the amphiblastula larva
hitherto described in other Calcarea. The minute larvce (70 — 80 /*,
in length, 50 — 60 fi in breadth) leave the mother sponge by the
osculum, and at once rise to the surface of the water, where they
swim for about twenty-four hours. They then sink to the bottom,
where, after swimming about slowly for twelve to twenty-four hours
more, they fix themselves and undergo metamorphosis. The larval
life thus lasts for thirty-six to forty-eight hours.
The oval larva (figs. 1 and 2)* is divided into an anterior region
composed of ciliated cells and a posterior region composed of non-
ciliated granular cells. The centre of the transparent larva is occu-
pied by a conspicuous mass of yellowish-brown pigment. The
ciliated cells are slender and elongated, reaching from the pigment to
the surface of the body. Each cell bears a single flagellum, and the
body of the cell is divided into an internal refractile portion and an
external granular portion. These two portions of the cell are so
distinct in the living object that a superficial examination gives the
impression of an internal layer of refractile cells covered by an
external granular layer, but by more careful investigation it is easy
to make out that these two apparent layers are merely parts of a
single layer of cells. The ciliated cells situated more posteriorly
entirely lack the retractile inner portion, and appear granular
throughout. They are also slightly broader, and have more convex
outer surfaces than the other ciliated cells, forming an equatorial
zone of intermediate cells, not very distinct in the living object. The
* Figs. 1 — 6 represent the development of L. varialilis, x 1000 diameters. All
but 1 and 2 are semidiagrammatic and combined from different preparations.
44 Mr. E. A. Minchin. Note on the Larva and the
FiG. 1. — Newly hatched larva.
region of the intermediate cells is generally marked by a slight con-
striction, giving a waist, as it were, to the larvae. The granular cells
are much fewer in number than the other elements, and are also of
much larger size, but there are gradations in this respect, those
placed at the posterior pole being much larger than those which
border upon the intermediate cells.
During the free-swimming larval period, considerable changes take
place in the relative proportions of the different parts of the larvae.
In the newly hatched larva (fig. 1) the anterior ciliated region is
relatively large, with a very broad granular border to the cells, and
the posterior granular cells are few in number. The number of
granular cells now increases at the expense of the ciliated cells.
Some of the ciliated cells, by absorption of the internal refractile
portion of the cell, become intermediate cells, and these, in their turn,
absorb their flagellum, increase in size, and become granular cells.
This process goes on pari passu with a decrease in the granular
border of the ciliated cells. In the larva of about twenty-four hours
(fig. 2), the granular cells form a mass equal to that of the ciliated
cells, and the latter have now a very narrow granular border. In
Postlarval Development of Leucosolenia variabilis, H. sp. 45
FIG. 2. — Larva of second day.
short, granular cells are formed during larval life by modification of
ciliated cells, the intermediate cells being a stage in this process.
Sections of larvae confirm and amplify the results obtained from a
study of the living object (fig. 3). The inner portion of each ciliated
cell, which in life appeared refractile, is seen to contain a series of
vacuole-like structures, containing granular masses suspended in
their interior. At the junction between the internal vacuolated and
external granular portions of the cell is situated the opaque and
deeply staining nucleus, which has a form like an onion, and is con-
tinued externally into the flagellum. Often the inner side of the
nucleus is indented by the vacuole beneath it, sometimes to such an
extent that the nucleus has the form of a crescent in section. The
intermediate cells are very distinct in sections, and by some methods
of preservation and staining, e.g., osmic acid followed by picrocarmine,
their protoplasm takes up the stain in a remarkable manner, so that
larvae treated in this way appear to have a brightly coloured equatorial
zone. They lack the vacuolated inner portion, characteristic of the
46
Mr. E. A. Minchin. Note on tJie Lama and the
Ffa. 3. — Longitudinal section of larva.
ciliated cells proper, and their nuclei are larger and paler with one
or two nucleoli. The nucleus of the first intermediate cell frequently
presents a curious appearance, being swollen out into a large vesicular
structure containing two or three chromatin masses. This condition
is apparently in connexion both with a process of rearrangement of
the chromatin and with the absorption of the vacuoles. The granular
cells are arranged in a single layer, and have large pale nuclei with
nucleoli. Often the nucleus of the cell nearest the intermediate cells
has a pointed outer end, evidently indicating the former connexion
with the flagellum.
Sections reveal a remarkable set of structures in connexion with
the central pigment, which is now seen to have the form of a tube,
open in front and behind, and enclosing a rounded, lens-like body,
apparently a gelatinous mass filling the central cavity, the remnant,
doubtless, of the segmentation cavity. Behind these bodies are a
number of cells with coarse granules and small, very opaque, deeply
staining nuclei.* One of these cells is placed in the longitudinal axis
* Cf. Dendy's account of the larva of Crrantia la'byrinthica for similar cells, " On
the Pseudogastrula stage in the Development of Calcareous Sponges," ' Roy. Soc.
Yictoria Proc.,' 1889, pp. 93—101.
Postlarval Development of Leucosolenia variabilis, H. sp. 47
of the larva, and its nucleus is usually, but not always, elongated in
the same direction, so as to have a rod-like form. The whole struc-
ture, with pigment, lens-like body, and central granular cells, gives
strongly the impression of a primitive, light-perceiving organ. The
pigment itself is lodged in the inner ends of the ciliated and inter-
mediate cells, and is, no doubt, the same pigment as that observed by
Metschnikoff* and Schulzet in the inner ends of the ciliated cells in
the larva of Sycandra raphanus. As the intermediate cells pass into
the condition of granular cells, they leave the pigment behind, so
that the pigment is thickest in the region of the intermediate cells,
at the sides of the lens-like body.
The larva is thus composed of four kinds of cells, which may be
termed the ciliated, intermediate, granular, and central cells. Since
the intermediate cells are merely a transitional form between the
ciliated cells proper and the granular cells, we have to reckon with
three classes of cells only in the fully developed larva.
The fixation takes place by the anterior pole of the larva, and the
granular cells grow round the ciliated cells. The metamorphosis is
complete in a few hours. Sections of fixed stages of the first day of
fixation (fig. 4) show them to be composed of two very distinct cell
Fia. 4.— Section of larva shortly after fixation, the metamorphosis not quite
complete.
layers : (1) a compact central mass of cells, easily recognisable, by
their opaque, irregularly shaped nuclei and vacuolated cell protoplasm,
as the former ciliated cells, surrounded by (2) a single layer of
flattened epithelial cells, the former granular cells of the larva. . No
trace is to be found of the central cells, which appear to be thrown
out together with the pigment, at the metamorphosis. The inner
mass is" the future gastral layer of the sponge, the outer epithelium
the future dermal layer.
* «Zur Entwicklungsgeschichte der Kalkschwamme," ' Zeitschr. f . Wiss. Zool,'
V°f " Ueber den Bau u'nd Entwicklung von Sycandra raphanus," ib., vol. 25, suppl.,
pp. 247-280, Taf. XVIII-XXI.
48 Mr. E. A. Minchin. Note on the Larva and the
The two component layers very soon begin to undergo changes of
form and structure, which are best described separately, since the two
layers develop more or less independently of one another, and a given
stage in the development of one layer is not always found combined
with one and the same stage in the development of the other.
The dermal layer becomes divided (fig. 5) into two kinds of cells r
(a) cells which retain the original form and characters and remain on
the surface, and (b) cells with smaller nuclei, which sink below the
outer epithelium and form a scattered layer between it and the
FlG. 5.— Section of stage about twenty-four hours after fixation. The left side is
represented as slightly in advance of the right side.
gastral cells. The former (a) secrete each a single monaxon spicule,
which appears first on the inner side of the nucleus, but soon grows out
and projects free from the surface. The latter (6) unite into groups
and secrete the triradiate spicules. The monaxons appear first, as in
Sycandra raplianus* and begin to appear about twenty-four hours
after fixation, the triradiates about twelve hours later. The dermal
layer has thus become divided into two parts, which gradually assume
the adult characters. I have not observed the origin of the pores.
The gastral layer, at first a compact mass with no definite arrange-
ment, soon begins to form a cavity (fig. 5). The cells assume a
radiate arrangement, and a split-like lumen appears in the centre.
Sometimes two or more such lacunar spaces arise, at first quite
independent of one another, but later fusing to form a single gastral
cavity, which soon becomes very large, causing the larva to increase
considerably in size as a whole. At first the cavity is surrounded on
all sides by gastral cells, but as it increases in size a spot appears
where gastral cells are wanting, and the cavity is limited only by
dermal cells (fig. 6). This is the region of the future osculum, and
the dermal cells at this spot form the future oscular rim, where collar
* Metschnikoff, loc. cit.
Fostlarval Development of Leucosolenia variabilis, H. sp. 49
¥10. 6. — Section of stage of about the fourth day of fixation.
cells are lacking. The gastral cells are at first elongated, but later
become shorter, and take on the characteristic appearance of collar
cells. I have not been able to make out whether all the gastral cells
become collar cells, or whether some of them do not become the
wandering cells of the adult, which seems very probable. The
osculum appears about the sixth day of fixation.
The Development of Leucosolenia cerebrum, H, L. reticulum, 0. S.,
and L. coriacea, Mont.
These three species have larvae of the type with which we are
familiar from the descriptions of Metschnikoff * and Schmidt, f
namely, oval ciliated blast ulee, in which an inner mass is formed by
immigration of cells into the interior. The process is most easily
followed in the more transparent larva of L. reticulum (fig. 7), where
the modification of ciliated cells into granular cells, and their sub-
sequent immigration, takes place at the posterior pole. When the
larva is ready for fixation, a considerable quantity of granular cells
has been formed, though the cavity is far from being obliterated. In
the opaque larvae of L. cerebrum and coriacea the process is more
* " Spongiologische Studien," 'Zeitschr. f. Wiss. Zool.,' vol.32, p. 362, Taf.
XXIII.
f " Das Larvenstadium von Ascetta clatkrus und Ascetta primordialis" ' Arch. f.
Mikr. Anat.,' vol. 14, pp. 249—263, Taf. XV, XYI.
YOL. LX. B
50 Mr. E. A. Minchin. Note on the Larva and the
FIG. 7. — Optical section of larva of L. reticulum, first day, x 500.
difficult to follow, but in both immigration appears to take place
from any point on the surface.
In L. cerebrum and L. reticulum the larva swims for about
twenty-four hours at the surface, and as long at the bottom, and fixes
on the third day. L. coriacea, on the other hand, is remarkable for
its abbreviated larval period as compared with the two Mediterranean
species, since the larva fixes in a few hours, a fact doubtless in con-
nexion with its life between tide marks, where the violent currents to
which it is exposed renders a very sheltered, and therefore limited,
habitat necessary for so delicate an organism.
After fixation, the larva undergoes changes whereby the ciliated
cells become surrounded by the formerly internal granular cells, so
that the ciliated external layer of the larva represents the gastral
layer of the adult, while the inner mass becomes the dermal layer ;
the reverse of what was supposed by Metschnikoff and Schmidt (loc.
cit.) to take place.
In L. cerebrum I was able to observe the first appearance of the
spicules. As in variabilis, the complete metamorphosis results in a
stage in which the gastral cells form a compact internal mass, snr-
Postlarval Development of Leucosolenia variabilin, //. Sp. 51
rounded by a single layer of dermal cells. Some of the cells of the
dermal epithelium then form themselves into groups, usually of three
cells, and each cell of such a group secretes the ray of a spicule. The
first spicales are usually triradiate, but quite irregular in form, and
at their first appearance they are quite superficial, their secreting
cells forming part of the general epithelium, but later they become
covered by the remaining epithelium, so that the dermal layer
becomes divided into an internal connective tissue layer and an
external flat epithelium. The process is essentially similar to that
occurring in variabilis, except that in the latter the cells of the flat
epithelium secrete each a monaxon spicule, which in cerebrum is not
the case.
General Considerations.
The larva of L. variabilis is of interest as affording a transition
from larvae such as that of L. reticulum, to the amphiblastula larva
of the Sycons. The larva of reticulum (fig. 7) is composed of (1)
ciliated cells, comparable to those of the amphiblastula, of which
some (2) at the hinder pole are undergoing modification, and may be
compared with the intermediate cells, and of (3) internal granular
cells comparable to the posterior granular cells of the amphiblastula.
To obtain a larva like that of variabilis from the type represented
by reticulum, we must suppose the large cavity of the latter reduced
to the extent to which this has occurred in the former. Then the
granular cells which are formed at the posterior pole must remain
where they are, since the cavity is too small to contain them, and, as
more ciliated cells are continually being modified arotmd them, we
get a larva with the three kinds of cells arranged as in variabilis.
The central cells of variabilis — on the origin of which I have no
observations to bring forward — are probably to be regarded as con-
stituting a larval organ, [a, special adaptation of no importance for the
postlarval development.
The development of both reticulum and variabilis points to an early
stage in which the larva is composed entirely of similar and equi-
valent ciliated cells. I have not seen such a stage in any species, and
doubt if it actually occurs in nature ; it is more probable that the
process of cell differentiation, begins before the larva is hatched in all
cases. In the absence of segmentation stages, it is impossible to
decide this question; nevertheless, the facts seem to me to indicate, as
the primitive larva in ascon phylogeny, a blastula composed of indif-
ferent ciliated cells, in which a second type of cells (the future dermal
layer) is formed by modification of certain of the cells. The collar-
cell layer of the adult is derived directly from the primitive ciliated
cells of the blastula.
Comparing, now, the larva of variabilis with that of Sycon raphanus,
52 On the Larva and Development of Leucosolenia variabilis.
as described by Schulze, it is obvious that the development is essen
tially similar in both, the chief difference being with regard to the
periods at which the various events take place. In both the granular
cells increase greatly in number, but in raphanus this takes place
while the larva is still in the maternal tissues, ' as is obvious from
Schulze's figures,* and the larva is hatched in a condition similar
to that of variabilis when about to fix. In variabilis the granular
cells do not surround the ciliated cells until after fixation ; in raph-
anus this process is begun while the larva is still swimming, and
the granular cells may even give rise to spicules (monaxons) during
the free swimming period (Metschnikoff, loc. cit.). It is obvious
that in Sycon we have before us a hastening and shortening of the
development, and, allowing for these embryological adaptations, we
are able to understand how, from a larva such as that of reticulum,
there has arisen a type of development apparently so different as
that of the Sycon amphiblastula.
The most important event in the post-larval development is the
differentiation of the dermal layer into the outer epithelium and the
inner connective tissue layer. This might seem at first sight to be a
process comparable to the formation of a new layer, a mesoderm ; so
that from this period onwards the sponge would be a three-layered
organism. I do not, however, take this view, for the following reason.
The immigration of cells from the epithelium to form the layer of
triradiates is not an event, like the formation of a germ layer, which
takes places once and for all in the life cycle of an individual, but it
goes on whenever new triradiates are formed. In adult ascons I have
found that the triradiates and the basal rays of the quadriradiates
arise from cells of the outer epithelium which migrate inwards and
arrange themselves into groups to form spicules, each ray being
secreted by one cell or by cells derived from the division of a
single cell. In the adult also the nuclei of the spicule secreting cells
diminish in size after quitting the epithelium. Hence in the develop-
ment of the sponge also, I regard this process as one not of blasto-
genetic, but of histogenetic significance. The fact that in variabilis
the epithelial cells also secrete spicules is to my mind a decisive
proof of the unity of the dermal layer.f
» ' Zeitschr.f. Wiss. Zool.,' vol. 25, suppl., Taf. XX and fig. 3, Taf. XIX. Schulze
refers this increase in the number of the granular cells to their multiplication by
cell-division, but as the granular cells do not at the same time decrease in size, it
seems more probable that their increase is due, as in variabilis^ to their numbers
being recruited from the clear (ciliated) cells.
f Schulze has also figured very clearly the relation of the dermal cells to the
monaxon spicules, one epicule to each cell, in the young fixed stages of Sycon
raphanus (' Zeitschr. f . Wiss. Zool.,' vol. 31, pi. XIX, figs. 10, 11), although he
states in the text that the spicules arise in the hyaline substance between the two
layers.
Helium and Argon, their Inactivity. 53
" Helium and Argon. Part III. Experiments which show
the Inactivity of these Elements." By WILLIAM RAMSAY,
Ph.D., F.R.S., and J. NORMAN COLLIE, Ph.D., F.R.S.E.
Received April 22,— Read May 21, 1896.
To chronicle a list of failures is not an agreeable task ; and yet it
is sometimes necessary, in order that the record of the behaviour of
newly discovered substances may be a complete one. It is with this
object that we place on record an account of a number of experiments
made to teat the possibility of forming compounds of helium and
argon.
It will be remembered that in our memoir on Argon,* Lord
Rayleigh and Professor Ramsay described numerous experiments,
made in the hope of inducing argon to combine, all of which
yielded negative results. Two further experiments have been since
made — again without success.
1. The electric arc was maintained for several hours in an atmo-
sphere of argon. The electrodes were thin pencils of gas carbon,
and, previous to the introduction of the argon, the arc was made
in a vacuum, and all gas evolved was removed by pumping. Argon
was then admitted up to a known pressure, and the arc was again
made. A slow expansion took place ; one of the electrodes di-
minished in length, and the bulb became coated with a black deposit.
The resulting gas was treated with caustic soda and with a solution
of ammoniacal cuprous chloride, and, on transference to a vacuum-
tube, it showed the spectrum of argon along with a spectrum
resembling that of hydrocarbons. Having to leave off work at this
stage, a short note was sent to the * Chemical News ' on a Possible
Compound of Argon. On resuming work after the holidays, the gas
was again investigated, and, on sparking with oxygen, carbon dioxide
was produced. Bat it was thought right again to treat the gas with
cuprous chloride in presence of ammonia, and it now appeared that
when left for a sufficient time in contact with a strong solution,
considerable contraction took place, carbonic oxide being removed.
There can, therefore, be no doubt that, although apparently all gas
had been removed from the carbon electrodes before admitting argon,
some carbon dioxide must have been still occluded, probably in the
upper part of the electrodes, and that the prolonged heating due to
the arc had expelled this gas and converted it into monoxide. It
was, indeed, inexplicable how an expansion should have taken place
unless by some such means; for the combination of a monatomic
gas must necessarily be accompanied by contraction. It appears,
therefore, certain that argon and carbon do not combine, even at
* < Phil. Trans.,' vol. 186, A.
54 Drs. W. Ramsay and J. Norman Collie.
the high temperature of the arc, where any product would have a
chance of escaping decomposition by removing itself from the
source of heat. It is hardly necessary to point out that such a
process lends itself to the formation of endothermic compounds
such as acetylene, and it was to be supposed that if argon is
capable of combination at all, the resulting compound must be
produced by an endothermic reaction.
2. A product rich in barium cyanide was made by the action of
producer gas on a mixture of barium carbonate and carbon at the
intense temperature of the arc. This product was treated by Dumas'
process so as to recover all nitrogen ; and, as argon might also have
entered into combination, the nitrogen was absorbed by sparking.
All the nitrogen entered into combination with oxygen and soda,
leaving no residue. Hence it may be concluded that no argon
enters into combination. For the successful carrying out of these
experiments we have to thank Mr. G. W. MacDonald.
3. A mixture of argon with the vapour of carbon tetrachloride
was exposed for several hours to a silent discharge from a very
powerful induction coil. The apparatus was connected with a
gauge which registered the pressure of the vapour of the tetra-
chloride and of the argon of which it was mixed. Careful measure-
ment of the pressure was made before commencing the experiment,
and after its completion. Although a considerable amount of other
chlorides of carbon was produced, no alteration of pressure was
noticeable; the liberated chlorine having been absorbed by the
mercury present. Here again the argon did not enter into the
reaction, but it was recovered without loss of volume.
The remaining experiments relate to attempts to produce com-
pounds of helium. The plan of operation was to circulate helium
over the reagent at a bright red heat, and to observe whether
any alteration in volume occurred — an absorption of a few c.c.
could have been observed — or whether any marked change was pro-
duced in the reagent employed. As a rule, after the reagent had
been allowed to cool in the gas, all helium was removed with the
pump, and the reagent was again heated to redness, so as, if a com-
pound had been formed, to decompose it and expel the helium.
Every experiment gave negative results ; in no case was there any
reason to suspect that helium had entered into combination.
A short catalogue of the substances tried may be given.
4. Sodium distilled in the current of gas, and condensed in drops
with bright metallic lustre. The glass tube in which it was heated
became covered with a coating of
5. Silicon, which caused no absorption.
6. A mixture of beryllium oxide and magnesium, yielding metallic
beryllium, was without action.
Helium and Argon, their Inactivity. 55
7. Zinc and, 8, cadmium distilled over in the current of gas.
9. A mixture of boron oxide and magnesium dust, giving ele-
mental boron, produced no absorption.
10. Similarly, a mixture of yttrium oxide and magnesium dust
had no effect.
11. Thallium was heated to bright redness in the gas, retaining
its metallic lustre.
12. Titanium oxide mixed with magnesium dust was heated to
bright redness, and caused no absorption.
13. Similar absence of action was proved with thorium oxide and
magnesium powder.
14. Tin and, 15, lead, were heated to bright redness in the current
of gas, and remained untarnished.
16. Phosphorus was distilled in the gas, and caused to pass through
a length of combustion-tube heated to softening. Some red phos-
phorus was formed, but no alteration of volume was noticed.
17. The same process was repeated with elemental arsenic.
18. Antimony and, 19, bismuth, at a bright red heat, retained their
metallic lustre.
20. Sulphur and, 21, selenium, were treated in the same way as
phosphorus ; no action took place.
22. Uranium oxide, mixed with magnesium dust, was heated to
bright redness in helium. No change, except the reduction of the
>xide, took place. The mixture was allowed to cool slowly in the
irrent, and the helium was removed with the pump till a phos-
)horescent vacuum was produced in a vacuum tube communicating
rith the circuit. The mixture was re-heated, and no helium was
rolved— not even enough to show a spectrum. The vacuum remained
[impaired.
It had been hoped that elements with high atomic weight, such as
thallium, lead, bismuth, thorium, and uranium might have effected
)mbination, but the hope was vain.
23. A mixture of helium with its own volume of chlorine was
exposed to a silent discharge for several hours. The chlorine was
contained in a reservoir, sealed on to the little apparatus which had
the form of an ozone apparatus. ISTo change in level of the sulphuric
acid confining the chlorine was detected after the temperature, raised
by the discharge, had again become the same as that of tlie room.
Hence helium and chlorine do not combine.
24. Metallic cobalt in powder does not absorb helium at a red heat.
25. Platinum black does not occlude it.
26. It is not caused to combine by passage over a mixture of
soda- lime and potassium nitrate heated to bright redness. This was
hardly to be expected, for it resists the action of oxygen in presence
of caustic soda, even when heated by the sparks which traverse it.
56 Lord Rayleigh. On the Amount of Argon and
27. A mixture of soda-lime and sulphur consisting of polysulph-
ides causes no change of volume in a current of helium passed over
it at a bright red heat.
28. Induction sparks in an ozone apparatus passed through a mix-
ture of helium with benzene vapour in presence of liquid benzene
for many hours, gave no change of volume. The benzene was, of
course, altered, but the sum of the pressures of the helium and the
benzene- vapour remained as at first. Had helium been removed,
contraction would have occurred.
This ends the catalogue of negative experiments. Any compound
of helium capable of existence will probably be endo thermic, and the
two methods of producing endothermic compounds, where no simul-
taneous exothermic reaction is possible, are exposure to a high tem-
perature, at which endothermic compounds show greater stability,
and the influence of the silent electric discharge. These methods
have been tried, so far in vain. There is, therefore, every reason to
believe that the elements, helium and argon, are non-valent, that is,
are incapable of forming compounds.
"On the Amount of Argon and Helium contained in the
Gas from the Bath Springs."* By LORD RAYLEIGH,
Sec. R.S. Received April 30,— Read May 21, 1896.
The presence of helium in the residue after removal of nitrogen
from this gas was proved in a former paper, f but there was some
doubt as to the relative proportions of argon and helium. A fresh
sample, kindly collected by Dr. Richardson, has therefore been ex-
amined. Of this 2500 c.c., submitted to electric sparks in presence
of oxygen, gave a final residue of 37 c.c., after removal of all gases
known until recently. The spectrum of the residue, observed at
atmospheric pressure, showed argon, and the D3 line of helium very
plainly.
The easy visibility of D3 suggested the presence of helium in some
such proportion as 10 per cent., and this conjecture has been con-
firmed by a determination of the refractivity of the mixture. It may
be remembered that while the refractivity of argon approaches
closely that of air, the relative number being 0'961, the refractivity
of helium (as supplied to me by Professor Ramsay) is very low,
being only 0*146 on the same scale. If \ve assume that any sample
* I am reminded by Mr. Whitaker tliat helium is appropriately associated with
the Bath waters, which, according to some antiquaries, were called by the Eomans
Aqua Soils.
t 'Boy. Soc. Proc.,' vol. 59, p. 206, 1896.
Magnetised Iron, $c., cooled to Temperature of Liquid Air. 57
of gas is a mixture of these two, its refractivity will determine the
proportions in which the components are present.
The observations were made by an apparatus similar in character
to that already described, but designed to work with smaller quan-
tities of gas. The space to be filled is only about 12 c.c., and if the
gas be at atmospheric pressure its refractivity may be fixed to about
1/1000 part, By working at pressures below atmosphere very fair
results conld be arrived at with quantities of gas ordinarily reckoned
at only 3 or 4 c.c.
The refractivity found for the Bath residue after desiccation was
0*896 referred to air, so that the proportional amount of helium is
8 per cent. "Referred to the original volume, the proportion of helium
is 1P2 parts per thousand.
" On the Changes produced in Magnetised Iron and Steels
by cooling to the Temperature of Liquid Air." By JAMES
DEWAR, LL.D., F.R.S., Fullerian Professor of Chemistry in
the Royal Institution of Great Britain, and J. A. FLEMING,
M.A., D.Sc., F.R.S., Professor of Electrical Engineering in
University College, 'London. Received April 25, — Read
May 21, 1896.
The action of the low temperature produced by liquid air upon the
magnetic moment of steel magnets was studied by one of us in a few
cases in a preliminary research made some time ago.* We have re-
cently returned to the subject and made further investigations on
the influence of the low temperatures thus obtained on magnetised
iron and steels of very various compositions, with the object of de-
termining the nature of the changes which take place in the
magnetic moment of small magnets constructed of these metals,
when cooled gradually or suddenly down to the lowest temperature
obtainable by the use of boiling liquid air. The arrangements adopted
in this investigation were as follows : —
A reflecting magnetometer consisting of three small magnetised
needles of watch-spring steel, cemented to a concave glass mirror,
suspended by a single cocoon fibre, was placed in a tube so as to be
free from disturbance by draughts of air. The small magnets were
8 to 10 mm. in length. The image of a portion of the filament of
an incandescent lamp was reflected by the mirror on to a divided
scale placed at a distance of 70 cm. from the mirror. The edge of
the very sharp image of the filament, focussed upon the scale,
* Friday evening discourse at the Koyal Institution, "On the Scientific Uses of
Liquid Air," by James Dewar, LL.D., F.E.S., January 19, 1894.
VOL. LX. F
58 Profs. J. Dewar and J. A. Fleming. Changes produced in
enabled any angular displacement of the magnetometer needle to be
easily determined. The position of this magnetometer needle was
regulated by the field produced by an external controlling magnet.
The small magnet, the behaviour of which at low temperatures was
to be studied, was placed behind the magnetometer, with its centre at
a distance of 1 to 10 cm. from the centre of the magnetometer needle
and its axis in a direction passing through the centre of the magneto-
meter needle, and at right angles to the direction of the undis-
turbed magnetometer needle. The magnet to be examined was fixed
to a brass wire, held in a wooden support in such fashion that the
magnet under examination could be easily removed from its position
behind the magnetometer, and restored to it again exactly. A large
number of samples of steel and iron were then prepared in the form
of small needles, generally 15 mm. long and about 1 mm. in diameter.
These steels comprised nickel steels, with various percentages of
nickel; chromium steels, with various percentages , of chromium;
aluminium steels, with various percentages of aluminium ; tungsten
steels, manganese steels, silicon steel, ordinary carbon steels in
various states of tempering, soft-annealed transformer iron, soft-
iron wire, and the same irons hardened by hammering. For most
of these samples of steels we were indebted to Mr. R. A. Hadfield,
of Sheffield, who kindly furnished them* to one of us in the form of
wires.
These short steel magnets were then all magnetised to " satura-
tion " by placing them for a few moments between the poles of a
powerful electro -magnet. One by one they were then placed .in
position behind the magnetometer, and the deflection produced on
the magnetometer needle observed. In any particular case this
deflection may be taken as approximately representing the intensity
of magnetisation of the sample, although, owing to the varying sizes
of the sample and distance from the magnetometer, the deflections in
the case of different magnets are not comparable with one another,
and cannot be taken as indicating the relative intensities of mag-
netisation of two different samples. This, however, was not impor-
tant, as our object was not to compare the absolute values of the
magnetisation of different classes of steels, but to observe the mode
of variation of the magnetisation of any one sample when cooled
from ordinary temperatures down to the temperature of liquid air.
The method of proceeding was then as follows : — Having adjusted
the image of the lamp filament to the zero of the scale, the small
magnet under observation was placed behind the magnetometer, and
the deflection of the magnetometer needle observed. A small
vacuum-jacketed cup, filled with liquid air, was then brought up
underneath the sample, and by its aid the magnet cooled suddenly
in situ to a temperature in the neighbourhood of —186° C. In the
Magnetised Iron, $-c.t cooled to Temperature of Liquid Air. 59
many cases this sudden cooling immediately deprived the magnet of
a considerable percentage of its magnetisation, and the magnetic
moment was reduced. This, however, was not universally the case.
In some cases, as in that of the chromium steels, the first effect of
this sudden cooling was an increase in the magnetic moment of the
magnet ; in other cases hardly any change in the magnetic moment
at all. The vessel of liquid air was then removed, and the magnet
allowed to heat up again, which it very quickly did, to the tempera-
ture of the room, or rather to a temperature at which the deposit of
snow formed upon the needle immediately on coming out of the
liquid air, fully melted. This was taken to be afc about 5° C. It
was found that each magnet had certain peculiarities of its own.
Taking first the ordinary carbon steel (a sample of knitting-needle
steel) we observe the following facts : —
Knitting-needle Steel (a) Tempered Glass Hard. — -The first effect
of cooling this magnet was to diminish the magnetic moment by
6 per cent. On allowing the magnet to heat up again to the
ordinary temperature, the magnetic moment still further dimin-
ished by about 16 per cent. On cooling again the magnetic moment
increased 10 per cent., and from and after that time cooling the
magnet always increased the magnetic moment, and allowing to
heat up again to ordinary temperature always diminished the
magnetic moment, the magnetic moment at — 185° C. being about
10 per cent, greater than the magnetic moment at 5° C. The first
effect, therefore, of the cooling was to permanently diminish the
magnetic moment, but after a few alternations of heating and cooling,
the magnet reached a permanent condition in which its moment,
when cold, was greater than its moment when warm. These changes
of magnetisation may be best represented as in the diagram in fig. 1,
in which the firm lines represent to some arbitrary scale the moment
of the magnet when at its ordinary temperature of 5° C., and the
dotted lines represent to the same scale the moment of the magnet
when cooled to -185° C.
Knitting-needle Steel (b) Medium Temper. — The same general
results were obtained with knitting-needle steel tempered to a
medium temper. The first effect of the cooling to the low tempera-
ture was to diminish the moment of the magnet. On allowing it to
heat up again the moment of the magnet diminished still more. The
next cooling caused an increase of magnetic moment, and from and
after that time the steel settled down into a permanent condition in
which the magnetic moment was greater at — 185° C. than at 5° C.
by nearly 20 per cent, of its value at 5° C. (see fig. 2).
Knitting-needle Steel (c) Annealed Soft.— The same general course
of events was noticed in the case of the knitting-needle steel when
made soft by heating to a red heat and allowing it to cool very
F 2
60 Profs. J. Dewar and J. A. Fleming. Changes produced in
doo-
7oo
600-
5oo
400-
3oo
200
loo
FIG. 1. — Knitting-needle steel (glass hard).
slowly. In this case, however, the first diminution of magnetic
moment was still greater. On first immersion in the liquid air
the magnet lost about 33 per cent, of its moment. On allowing
it to heat up again to 5° C. it still further diminished in moment,
and from and after that point it arrived soon at a permanent
condition, in which its moment, when cold, was greater than its
moment when warm by 30 per cent, of its moment at 5° C. These
Magnetised Iron, $c., cooled to Temperature of Liquid Air. Gl
Zoo
loo*
FIG. 2. — Knitting-needle steel (medium temper).
changes of the medium- and soft-tempered steel are represented
by the lines in the diagrams 2 and 3, in which the firm lines are
proportional to the magnetic moment of the magnet at 5° C., and
the dotted lines proportional to the magnetic moment at — 185° C.
It will be seen that,, in the case of this carbon steel, the effect of
softening the steel is to make more pronounced the effect of the final
temperature changes ; the change of moment caused by cooling from
the ordinary temperature to the temperature of liquid air. when the
permanent condition has been reached, being in the case of the glass-
hard steel an increase of magnetic moment of about 12 per cent. ; in
the case of the same steel with a medium temper about 22 per cent.,
and in the case of the same steel tempered very soft about. 33 per
cent, (see fig. 3).
Chromium Steels. — Observations were then made with the magnets
of chromium steel, having respectively 0'29 per cent., 1'18 per cent.,
5'44 per cent., and 9'18 per cent, of chromium. In all these cases
the first effect of cooling the magnet was to cause at once an increase
of magnetic moment, and the subsequent heating up again to the ordi-
nary temperature caused a decrease of magnetic moment. These
62 Profs. J. Dewar and J. A. Fleming. Changes produced in
600-
2oo
100
FIG. 3. — Knitting-needle steel (tempered soft).
60-
FIG. 4. — Chromium steel.
Cr
C
Si
Mn
= 0-29
= 0-16
= 0-07
= 0-18
Fe = 99-30
o-
FIG. 5. — Chromium steel.
Cr = 1-18
C =0-27
Si = 0-12
Mn = 0-21
Fe = 98 -22
loo
50-
FIG. 6. — Chromium steel.
Cr = 5-44
C =0*27
Si = 0 '50
Mn = 0-61
Fe = 92-68
ICO
So-
o-
FIG. 7. — Chromium steel.
Cr = 9'18
C =0-71
Si = 0-36
Mn = 0-25
Fe = 89 -50
Magnetised Iron, #<?., cooled to Temperature of Liquid Air. 63
magnets arrived almost immediately at their permanent condition, in
which the magnetic moment, when cold, was greater than the mag-
netic moment when warm by about 12 per cent. The variation of
magnetic moment in the case of these magnets is shown by the dia-
grams 4, 5, 6, and 7, in which the firm lines represent the magnetic
moment when the magnet is at 5° C., and the dotted lines the mag-
netic moment at —185° C. It will be seen, therefore, that in the
case of the magnets there was 110 such initial decrease of magnetisa-
tion as in the case of the carbon steel magnets. The analysis of these
steels was furnished to us by Mr. Haclfield, and is appended to the
diagrams. These steels are all in their hard condition, and possess
considerable coercive force.
Aluminium Steels. — The aluminium steels employed had the follow-
ing percentages of aluminium, viz. : O72, 1/16, and V60. In all
these cases the first effect of cooling the magnet made of these steels
was to cause a very small diminution in the magnetic moment, but
not more than about 2 per cent, (see figs. 8, 9, and 10). The subse-
quent rise in temperature of the magnet again to its ordinary tem-
foo-
/oo-
FIG. 8. — Aluminium steel.
Al =
C =
Si =
Mn =
0-72
0-20
0-12
0-11
Fe = 98 '85
FIG, 9. — Aluminium steel.
Al = 1-16
C =0-26
Si = 0-15
Mn - 0-11
Fe = 98 -32
loo
5c
FIG. 10. — Aluminium steel.
Al = 1-60
C = 0-21
Si = 0-18
Mn = 0-18
Fe = 97 '83
perature, caused a still further fall in magnetic moment, and from
and after that point the effect of cooling down to the temperature of
64 Profs. J. Dewar and J. A. Fleming. Changes produced in
liquid air was to cause the magnet to possess a magnetic moment
about 10 per cent, greater at —185° C. than at 5° C. It will be seen,
therefore, that these steels differ from the chromium steels in this
respect, that whereas in the chromium steels the effect of the first
cooling is to cause an increase in magnetic moment ; in the case of
the aluminium steels, the effect of the first cooling was to cause a
decrease of magnetic moment, although much smaller relatively than
in the case of the carbon steels.
Nickel Steels. — Experiments were then made with samples of nickel
steel containing 0'94, 3'82, 7'65, 19'64, and 29 per cent, of nickel.
These steels exhibited some rather interesting peculiarities. In the
case of the nickel steel with O94 per cent, of nickel, the effect of the
first cooling in liquid air was to cause a very small decrease in mag-
netic moment (see fig. 11), and the subsequent heating and cooling
loo
So-
FIG. 11.— Nickel steel.
Ni = 0-94
C =0-13
Si = 0-23
Mn = 0-72
Fe = 97-98
brought the steel into a condition in which its magnetic moment,
when cold, was always greater than its magnetic moment when warm,
by about 10 or 11 per cent. In the case of the nickel steel with
3'82 per cent, of nickel, the effect of the changes of temperature
was very similar (see fig. 12), and also in the case of the nickel steel
having 7'65 per cent, of nickel the order of the changes was not very
different — in this respect, that the magnetic moment when cold was
IUU-
5c
F]
g. 12.— Nickel steel.
Ni = 3-82
C =0-19
Si = 0-20
Mn = 0-65
Fe = 95 -14
5o-
FIG. 13.— Nickel steel.
Ni = 7-65
C - 0-17
Si = 0-28
Mn = 0-68
Fe = 91 -22
Magnetised Iron, $c., cooled to Temperature of Liquid Air. 65
greater than the magnetic moment when warm, when the permanent
state had been reached. But it will he noticed from the diagrams (see
fig. 13) that in the case of the 7'65 per cent, nickel steel, the effect of
the first cooling was to cause a slight increase in magnetic moment. A
remarkable peculiarity, however, was found in the case of the 19'64 per
cent, nickel steel. In this case the effect of the first cooling was to
cause a very considerable reduction of magnetic moment, very nearly
50 per cent., that is to say, the magnetic moment fell instantly, on
cooling in the liquid air, to about half the value that it had at the
beginning of the experiment. On taking the magnet out of the liquid
air and allowing it to warm up again to the temperature of the room,
the magnetic moment immediately increased again, and from and after
that time the effect of the temperature change on the magnetic
moment was such that the magnetic moment, when cooled to the
temperature of liquid air, was always less than the magnetic moment
at 5° C. by about 25 per cent, of the latter value. These relative
changes are shown in the diagram (fig. 14). These experiments
Joo
loo-
loo
FIG. 14.— Nickel steel.
Ni = 19 -64
C =0-19
Si = 0-27
Mn = 0 -93
Fe = 78 '97
100-00
with the 19 per cent, nickel steel were repeated a great many times,
and always with the same general results. The sample of 29 per
cent, nickel steel was then examined, and it was found that the mag-
netic changes produced in it on heating and cooling were of the same
general character as in the case of the 19 per cent, sample, only less
66 Profs. J. Dewar and J. A. Fleming, Changes produced in
marked. Steels having these high percentages of nickel are, as Dr. J.
Hopkinson has pointed out,* remarkable for the wide range of tem-
perature within which they can exist in two states, one considerably
magnetic, and one practically non-magne'tic or but feebly magnetic.
In these two states their mechanical and other physical properties are
entirely different. In the experiments here mentioned, the nickel
steel samples were in the magnetic condition. They are put into this
condition by dipping for one moment in liquid air, and are only trans-
formed back into the feebly magnetic condition by heating to a
cherry-red heat. The 29 per cent, sample of nickel steel being in the
magnetic condition was magnetised by contact with the poles of the
efectromagnet. On cooling it in liquid air it immediately lost about
20 per cent, of its moment, on warming up again to 5° C. it lost about
5 per cent, more, and from and after that point remained in a condi-
tion in whiph cooling the magnet to —185° C. caused its moment to
become about 10 per cent, less than it was at 5° C. Hence the 29 per
cent, nickel steel exhibits the same quality but in a less marked
degree than the 19 per cent., in that its magnetic moment is decreased
by cooling to -—185° C., and recovers again on heating up to 5° C.
In this respect the two samples of nickel steel differ from all other
samples of steel which we have examined, in that they have a negative
temperature coefficient for magnetic moment change with tempera-
ture, after the first change on cooling has taken place.
Pure Nickel. — In order to see if this peculiarity extended to pure
nickel, we examined the behaviour of a small magnet made with
Mr. Mond's pure nickel, but we found that such a nickel magnet,
magnetised to saturation, behaved exactly as did a carbon steel
magnet (see fig. 15). The effect of the first cooling to the tempera-
ture of liquid air was to diminish the magnetic moment. On allow-
ing the magnet to heat up again to the ordinary temperature the
moment diminished still more, and from and after that time the
behaviour of the magnet was perfectly normal, that is to say, its
magnetic moment when at 5° C. was less than its magnetic moment
at —186° C., but only by about 3 or 4 per cent, of the latter value.
Silicon Steel. — A. sample of silicon steel, containing 2'67 per cent,
of silicon, behaved in a normal manner (see fig. 16). The magnet
experienced a permanent diminution of moment on cooling for the
first time, and after that, its magnetic moment when cold was greater
than its magnetic moment when warm.
Soft Iron. — In order to determine if similar changes of magnetic
moment could be produced in the case of soft annealed iron, small
magnets of Swedish iron were prepared, formed of a short length,
about 15 mm., of soft iron, or a small slip of annealed transformer
iron. On magnetising these in a strong field, and testing them with
* ' Koy. Soc. Pi-oc.,' 1890, vol. 47, p. 138.
Mam-ietised Iron, $c., cooled to Temperature of Liquid Air. 67
doc
7oo
600
5oo
300
^oo
loo.
FIG-. 15. — Mond's pure nickel,
the magnetometer, and cooling them by immersing in liquid air, it
was found that the first effect of the cooling was to produce a small
diminution in the magnetic moment, and the subsequent heating in
some cases produced a further diminution of magnetic moment. In
the first sample of soft iron, the wire was about 3 cm. long, and bent
68 Profk J. Dewar and J. A. Fleming. Changes produced in
too-
5o-
FIG. 16. — Silicon steel.
Si = 2-67
C =0-20
Mn = 0-25
Fe = 96 -88.
into a U shape, with ends about 10 mm. apart, and in this case the
changes of magnetic moment, as shown in fig. 17, were similar to
2oo--
loo-
o-
FIG. 17. — Soft iron.
those in the case of the carbon steels, only with very much narrower
limits of variation. The first cooling hardly produced any change
whatever in the magnetic moment of the magnet. On allowing it to
heat up again, the magnetic moment was very slightly diminished,
and thenceforth the changes of moment were such that the magnetic
moment was greater when the magnet was cold than when it was
warm, by about 2 or 3 per cent, of the latter value. In the case of a
straight, soft iron magnet, formed of annealed transformer iron, the
curious fact was noticed that whereas a rapid cooling of the magnet
by plunging into liquid air hardly produced any effect on the magnetic
moment after the first initial loss of magnetism had taken place on
cooling, the effect of a slow cooling down to the temperature of
— 185° C. was always to produce a permanent diminution of magnetic
moment. Hence the magnetism of this soft iron sample could be
frittered away by a process of slow cooling to — 185° C., and inter-
mediate heating up to 5°C. These changes of moment are repre-
sented in the diagram of fig. 18.
Hard Iron. — A sample of the same iron, hardened by hammering,
was tested, and was found to behave in a very similar manner to the
Magnetised Iron, $c.9 cooled to Temperature of Liquid Air. 69
ICC
rapid slow
coo//n$. coolint.
i
i
i
i
i
i
i
i
i
•
i
i
i
i
i
i
n
mad.
li
n
sk
W- fcif
yd- rdn/d. slow. /
' 1 ' 1 ' i
i 1 i 1 i
^ rdpid.
i * i
i 1 i 1
FIG. 18
. — Annealed transformer iron.
loo
FlG. 19. — Hard transformer iron.
glass-hard carbon steel (see fig. 19), the changes in magnetic moment
being relatively about the same percentage for the same temperature
change : that is to say, the magnet had a moment of about 10 per
cent, greater at -185° C. than at 5° C.
A series of tungsten steels were then examined, having respec-
tively 1, 7'5, and 15 per cent, of tungsten in them.
Magnets were prepared of these steels, both in the glass-hard con-
dition and in a carefully annealed condition. These steels were found
to resemble the simple carbon steels in that the first effect of cooling
the magnet to — 186°C. was to cause a diminution of magnetic
moment, and the subsequent warming up again to 5° C., a still fur-
ther decrease in magnetic moment. From that time forth cooling
the magnet always caused an increase of magnetic moment. The
effect of increasing the percentage of tungsten was to cause a
decrease in the variation of the magnetic moment over a given tem-
perature range. That is to say, the hardened 15 per cent, tungsten
steel temporarily lost magnetic moment to the extent of about 6 per
cent, by heating up from — 185° C. to 5° C. when once the initial
condition had been passed. The 7'5 per cent, tungsten steel lost
moment to the extent of about 10 per cent., and the 1 per cent, tungsten
steel lost moment to the extent of about 12 per cent, when the tempera-
tures rose between the same limits. As regards these tungsten steels,
softening the steel caused the magnetic moment to decrease by a
greater percentage when heated up from —185° C. to 5° C. than was
found to be the case when the steel was in its hard condition. A
sample of manganese steel containing 12 per cent, of manganese was
rendered magnetic by heating for 24 hours to a dull red heat. A
small magnet prepared from this steel was found capable of retaining
70 Profs. J. Dewar and J. A. Fleming. Changes produced in
magnetism. On cooling it to —185° C., it slightly increased in mag-
netic moment, and on heating up again to 5° C., its magnetic moment
decreased to the extent of about 3 per cent, of its moment at — 185° C.
There was no initial decrease of moment in this case. In this
respect, therefore, it resembled the chromium steel magrets.
Broadly speaking, the results so far obtained are : —
(1) That the sudden cooling to the temperature of liquid air
usually permanently decreases the magnetic moment of short mag-
nets made of many varieties of steel, assuming them to have been
initially magnetised in a strong field.
(2) This initial decrease is found both in hardened steels having
great coercive force, and also in the same steels in a soft or annealed
condition, and is especially conspicuous in the case of the 19 percent,
nickel steel.
(3) In the case of most steels so far examined, the effect of cooling
magnets made of them to — 185° C. is to temporarily increase the
magnetic moment after the permanent magnetic condition has been
reached.
(4) The exceptions to the above rule so far noted are the nickel
steels with percentages of nickel from 39 to 29 per cent., in which
case the magnetic moment is always decreased temporarily by cooling
to —185° C., after the permanent magnetic condition has been
reached.
(5) It appears from these experiments that one of the best ways of
ageing a permanent magnet is to dip it several times into liquid air.
It then arrives at a constant condition in which subsequent tempera-
ture changes have a definite effect, and in which the subpermanent
magnetism is removed.
Note added May 4.
Since the 19 per cent, nickel steel magnet increases 'in magnetic
moment when heated from — 185° C. to +o°C., and since it is well
known that at some higher temperature it would lose magnetic
moment altogether, it was considered very desirable to ascertain the
temperature at which it would have its maximum magnetic moment.
The magnet was accordingly heated (on April 2) in an oil bath
gradually up to a temperature of about 300° C., and the deflections of
the magnetometer observed at intervals, both as the temperature rose
and as it fell. The result showed that this nickel steel magnet con-
tinued to increase in magnetic moment, until a temperature of about
30° C. was reached, and the magnetic moment then began to de-
crease.
At a temperature of +300° C., the moment of the magnet was not
much greater than it was at — 185° C. On cooling down again from
Magnetised Iron, fyc., cooled to Temperature of Liquid Air. 71
300° C., the moment increased, but not to the same maximum as
before, and on repeating the cycle of temperature from about 15° C. to
300° C., the magnetic moment gradually varied, in the manner shown
in fig. 20, and the temperature of maximum magnetic moment
-Zoo*
Variation of Magnetic Moment: of A
Nickel Steel tfagnet(i9-64%Ni.)
with Temperature.
-^oo?
-loo? o? +100? +100*
TemperaCure in Degrees Cent/grade.
+300-'
gradually shifted upwards to about 56° C. This magnet is, therefore,
an interesting case of a sample of steel which, when magnetised, has
a maximum magnetic moment at a certain temperature.
72 Profs. J. Dewar and J. A. Fleming. On the Electrical
to
;' On the Electrical Resistivity of Bismuth at the Tempera-
ture of Liquid Air." By JAMES DEWAR, LL.D., F.R.S.,
Fullerian Professor of Chemistry in the Royal Institution,
and J. A. FLEMING, M.A., D.Sc.', F.R.S., Professor of Elec-
trical Engineering in University College, London. Re-
ceived May 19,— Read June 4, 1896.
In the course of last year we published some observations (see
' Phil. Mag.,' September, 1895, p. 303)* on the electrical resistance
of bismuth at the temperatures of liquid and solid air, in which
the resistivity of certain samples of bismuth was measured at various
temperatures down to the temperature at which air solidifies. These
observations showed some anomalous results. In the case of two
samples of bismuth used by us, and prepared by different chemical
means, it was found that the resistivity reached a minimum value at
a temperature of about — 80°, and that after that point further cool-
ing increased the electrical resistivity of these samples of the metal.
In the case of another sample of commercial bismuth, the resistivity
curve was a curve of double curvature. These results, together
with the high absolute value of the resistivity of the samples, caused
us to feel a strong conviction that different results would be
obtained with bismuth prepared by an electrolytic method. Some
observers, particularly M. van Aubel, who have investigated the elec-
trical properties of bismuth, have expressed the opinion that bismuth
cannot be prepared in a state of perfect purity by any chemical means.
Finding the chemical methods of doubtful utility, we accordingly
solicited the assistance of Messrs. Hartmann and Braun, who have
devoted a large amount of attention to the preparation of pure electro-
lytic bismuth for the purposes of constructing spirals of bismuth for
measuring the strength of magnetic fields. They kindly prepared
for us at our request a considerable quantity of bismuth by an
electrolytic method, which examination showed to be exceedingly
pure, and this metal was pressed into a uniform wire with a diameter
of about half a millimetre. This electrolytic bismuth is very soft,
and in the form of wire can be bent without difficulty. Resist-
ance coils were accordingly constructed of this wire, of a form
suitable for use when measured in liquid air and at low temperatures.
In the case of one resistance coil, which may be denoted as electro-
lytic bismuth No. 1, the length of the wire employed was 8O85 cm. ;
the diameter of this wire was carefully measured with a microscopic
* " The Variation in the Electrical Eesistance of Bismuth when cooled to the
Temperature of Solid Air," Dewar and Fleming, 'Phil. Mag.,' September, 1895,
p. 303.
Resistivity of Bismuth at the Temperature of Liquid Air. 73
micrometer in twenty to thirty places, these diameters having very
nearly equal values, and a mean value of O05245 cm. The bismuth
wire so prepared was mounted on a suitable holder, and its resistance
was taken at several different temperatures and in liquid air, the
temperatures being in all cases measured by our standard platinum
thermometer iPj.*
The results of these measurements were as follows : —
Resistivity of Electrolytic Bismuth, No. I.
Temperature
in platinum
degrees.
Observed
resistance in
ohms.
Kesistivity in
C.G-.S. units
per cubic
centimetre.
Remarks.
+ 60° -5
+ 19°
4 '9857
4 -3464
133250
11G180
At ordinary temperature.
-61°'2
3 -1275
83590
In ether cooled with solid car-
bonic acid.
-202° -2
1-5256
40780
In liquid air.
The carve of resistivity plotted from these data is shown in fig. 1,
and in the table the value of the resistivity of bismuth in C.Gr.S.
units per cubic centimetre is given above. These values of the
resistivity show that in the case of this pure electrolytic bismuth
Fio. 1.
f 00,000- £
-Zoo*
-/«?•" o-
Temperature in Platinum Degrees.
+ loo?
* For details of this thermometer, see Dewar and Fleming on the " Thermo-
electric Powers of Metals and Alloys at the Boiling Point of Liquid Air," ' Phil.
Mag.,' July, 1895, p. 100.
VOL. LX. G
74 Profs. J. Dewar and J. A. Fleming. On the Electrical
there is no tendency of the resistivity carve to a minimum value.
Down to the lowest temperatures reached in these experiments, the
resistivity of bismuth continues to decrease in a perfectly regular
manner, and in such a way as to show that it would be no exception,
in all probability, to the ordinary law, that resistivity of pure metals
vanishes at the absolute zero of temperature. On comparing the
results of these measurements with those in the former experiments
made with chemically prepared bismuth, it is seen that the electro-
lytic bismuth used by us has a very much lower resistivity at 0° C.,
viz., 108,000 units, and it has a lower value than that given by
Matthiessen for pure bismuth, which is 129,700. We have, then, an
additional indication that the bismuth used by us in the experiments
in 1895 must have contained sufficient, though slight, impurity to
markedly alter its resistivity, and to change entirely the character of
the resistivity curve. With this- electrolytic bismuth we have repeated
the experiments which we made last year, on the variation of the
electrical resistance of bismuth when placed transversely to the
direction of the force in a magnetic field, and when cooled to the
temperature of liquid air. For this purpose we constructed a flat
spiral of the electrolytic bismuth, so arranged that its resistances
could be measured at ordinary temperatures, and at the temperature
of liquid air, by immersing it in a flat vacuum- jacketed test-tube,
both when in a powerful magnetic field, and when merely in the
terrestrial field. With this electrolytic bismuth we have confirmed the
observation which we made last year, with a small sample of electro-
lytic bismuth, viz., that the effect of a given transverse magnetic
field in increasing the resistivity of bismuth is immensely increased
by cooling the bismuth to the tempera.ture of liquid air. The figures
in the following table will show the actual results obtained in these
last experiments : —
Variation of Electrical Resistance of Electrolytic Bismuth in
Magnetic Fields of different Strengths.
Tempera-
ture in
platinum
degrees.
Magnetic field strengths in C.G-.S. units.
Bemarks.
Zero.
1400 units.
2750 units.
^Resistance of bismuth coil.
+ 20°
ohms.
1-679
olims.
1-700
ohms.
1-792
At ordinary temperature.
-202°
0-5723
1 -4435
2 -6801
In liquid air.
Resistivity of Bismuth at the Temperature of Liquid Air. 75
It will thus be seen that whereas the immersion of the electrolytic
bismuth wire, at ordinary temperatures, transversely in a magnetic
field of strength 2,750 C.G.S. units, only increased its resistance by
about 6 per cent., the immersion of the same wire in the same mag-
netic field increased its resistance to more than four and a half times
when it was cooled to the temperature of liquid air, and the effect of the
cooling with liquid air is more than nullified by the field, so that the'
bismuth cooled in liquid air and at the same time placed in the field
has a resistance of 50 per cent, greater than it was when not cooled
and not in the field. We are engaged in extending these observa-
tions to stronger fields.
The behaviour of electrolytic bismuth in fields of various strengths
and at various temperatures, from 0° C. to 100° C., has been studied
by Mr. J. B. Henderson (see ' Phil. Mag.,' vol. 38, ]894, p. 488), and
he has given a series of curves showing the variation of resistance of
bismuth between these temperatures for fields of strength varying
from zero to 22,700 C.G.S. units. Our observations at low tempera-
tures are quite consistent with Mr. Henderson's curves. His curves
indicate that at lower temperatures the effect of any given field in
increasing the resistance of the bismuth becomes more marked.
Pressed to its limit it would appear that pure bismuth, which
would in all probability be made a perfect conductor by reducing to
the absolute zero of temperature, would be then converted into a
non-conductor if at the same time immersed in a magnetic field of
sufficient strength. Both M. van Aubel and Mr. Henderson have
pointed out that the temperature coefficient of bismuth at any given
temperature is quite altered by placing it in a magnetic field, and it
will therefore be a matter of great interest to examine the effect of
an exceedingly strong magnetic field as bismuth when cooled to the
temperature of solid air.
By enclosing a bismuth wire and a platinum thermometer wire in
the same mass of paraffin wax we have been able to measure the
variation of resistance of the bismuth from the temperature of liquid
air up to ordinary temperatures at a number of intermediate points,
and to determine the resistance both in a zero magnetic field and
in one of known strength, but the results we wish to reserve until
we have had the opportunity of repeating them with stronger mag-
netic fields.
G t>
76 Profs. J. Dewar and J. A. Fleming. On the Electrical
" On the Electrical Resistivity of Pure Mercury at the Tem-
perature of Liquid Air." By JAMES DEWAR, LL.D., F.R.S.,
Fullerian Professor of Chemistry in the Royal Institution,
and J. A. FLEMING, M.A., D.Sc., F.R.S., Professor of
Electrical Engineering in University College, London.
Received May 19,— Read June 4, 1896.
Although the electrical resistivity of mercury at ordinary tem-
peratures has been carefully examined by many observers, and accu-
rate determinations made of the specific resistance* and temperature
coefficient, and in addition an examination made of the variation of
resistivity in mercury when cooled to temperatures as low as
100° C.,f we considered it would be of interest to examine the
behaviour of pure mercury in respect of change in electrical resist-
ivity when cooled to the temperature obtained by the employment of
boiling liquid air. With this object we prepared a sample of very
pure mercury in the following manner : Ordinary distilled mercury
was shaken up with nitric acid in the usual manner to free it from other
metals, and then carefully dried. It was then introduced into a bent
glass tube formed of hard glass. This bent tube had both ends sealed,
and a side tube connected in at the bend, by which it could be con-
nected to a mercury vacuum pump. Two or three hundred grammes
of the mercury was then introduced into one bend, and a high vacuum
made in the tube. The side tube was then sealed off from the pump,
and the mercury distilled over from one leg into the other. For this
purpose, one leg of the bent tube was placed in ice and salt, and the
other submitted to a gentle heat just sufficient to make the mercury
distil under reduced pressure without ever bringing it into active
ebullition. In this way the mercury is distilled over at a very low
temperature, and the portion condensing in the cooler limb of the
bent tube is entirely free from any contamination with silver, lead,
zinc, or tin. By performing this distillation two or three times suc-
cessively on the same mercury, a small quantity of mercury is at last
obtained in an exceedingly pure condition. A glass spiral tube
was then formed of lead glass, consisting of a tube having an
internal diameter of about 2 mm., and a length of about 1 metre.
This tube was bent into a spiral of about twelve close turns, each
turn being nearly 2'5 cm. in diameter, and the ends of this spiral
provided with enlarged glass ends formed of wider tube. The spiral,
* " The Specific Resistance of Mercury," by Lord Rayleigli and Mrs. Sidgwick
(Phil. Trans. R. S., Part I, 1883). See, also, Mr. E. T. GUazebrook (Phil. Mag.,
Oct., 1885), for other values.
f Cailletet and Bouty (Compt. Rend., 100, 1188, 1885).
Resistivity of Mercury at the Temperature of Liquid
Air. 77
after being cleaned, was then very carefully filled with the purified
mercury, and by running the mercury through a spiral several times,
all air bubbles and air film were finally removed. Into the wider
ends of the spiral, amalgamated copper electrodes were introduced,
consisting of copper wire 4'4 mm. in diameter ; the wider terminal
ends of the spiral were then closed by paraffined corks to keep the
copper electrodes in position. This spiral, full of mercury, was
placed in a test-tube, and paraffin wax cast round it so as to enclose
it entirely, leaving only the copper electrodes protruding. In order
to determine the temperature of the mercury in the glass spiral tube,
a platinum wire, the resistance of which was known at all tempera-
tures down to the temperature of liquid air, was also embedded in the
paraffin wax closely in contact with the glass spiral, and proper
electrodes brought out to enable the resistance of this platinum wire
to be determined. This mass of paraffin wax was then cooled down
in a vacuum vessel kept filled up with liquid air until the whole mass
reached the temperature of the liquid air. The glass spiral and
thermometer enclosed in wax was then removed from the bath of
liquid air and placed in a vacuum-jacketed test-tube, in order that it
might warm up with extreme slowness to the ordinary temperature
of the air.
Having in this manner cooled the mass of paraffin enclosing the
glass spiral filled with mercury and the platinum resistance wire
entirely to the temperature of liquid air, a series of observations were
taken with the aid of two observers, one measuring the resistance of
the mercury by a Wheatstone's Bridge, while at the same time the
other observer at another slide wire bridge measured the resistance
of the platinum wire, these observations being taken quite simul-
taneously, and continued whilst the mass heated up from — 197'9°
(platinum temperature) to 0°. All proper corrections were then
applied to correct for the resistance of the connecting wires and the
bridge temperature ; and the observed resistance of the platinum
wire employed was corrected to determine from its resistance tem-
peratures in terms of the standard platinum thermometer employed
by us in our investigations on the thermo-electric power of metals
and alloys (see Dewar and Fleming, 'Phil. IVIag.,' July, 1895, p. 95).
This standard thermometer has always been denoted by the letter Px.
The following table shows the corrected resistance of the mercury
column and the corresponding platinum temperatures, as also the
specific resistance of the mercury calculated from the accepted re-
sistivity at 0° C. :—
78 Profs. J. Dewar and J. A. Fleming. On the Electrical
Resistivity of Pure Mercury in C.Gr.S. Units at various Tempera-
tures in Platinum degrees.
Platinum temperature, pt,
in terms of tlie standard
platinum thermometer
Pi-
Observed and corrected
resistance of mercury in
lead glass spiral in ohms.
Resistivity of mercury
in glass in C.G.S.
units.
-197-9
0 '0551
6970
-197-8
0 -0551
6970
-197-5
0-0551
6970
-196-9
0-0566
7160
-195-2
0-0581
7350
-191-2
0-0601
7600
-182-7
0-0641
8100
-173-2
0 -0721
9120
-168-4
0 -0761
9620
-165-1
0 -0781
9870
-157-4
0 -0836
10570
-149-7
0 -0886
11200
-143-0
0 -0931
11770
-131 -9
0-1011
12780
-128-3
0-1041
13160
-122-9
0 -1081
13670
-117-5
0-1121
14170
-108-4
0-1191
15060
-103-7
0 -1231
15560
- 97-0
0 -1281
16200
- 91-1
0 -1331
16830
- 85-0
0 -1381
17460
- 79-1
0-1432
18100
- 73-1
0 -1482
18740
- 67-4
0-1532
19370
- 63-2
0-1582
20000
- 57-6
0 -1632
20630
- 52-5
0-1682
21270
- 48-9
0 -1753
22160
- 47-0
0-1833
23180
- 46-0
0 -1883
23810
- 44-9
0 -1933
24440
- 44-2
0 -1983
25070
- 43-5
0 -2033
25700
- 43-0
0-2183
27600
- 42-4
0 -2283
28860
- 42-1
0 -2383
30130
- 41-9
0 -2484
31410
- 41-2
0 -2584
32670
- 40-8
0 -2784
35200
- 40-6
0 -2884
36460
- 40-4
0-3184
40260
- 39-7
0-3585
45330
- 39-5
0 -3885
49120
- 39-4
0 -4185
52920
- 39-3
0-4385 -
55440
- 39-1
0 -4785
60800
- 38-7
0 -5186
65570
- 38-5
0 -5486
69360
- 38-3
0-5786
73160
- 37-7
0-6086
76950
Resistivity of Mercury at the Temperature of Liquid Air. 79
Platinum temperature, pt,
in terms of the standard
platinum thermometer
PL
Observed and corrected
resistance of mercury in
lead glass spiral in ohms.
Resistivity of mercury
in glass* in C.G.S.
units.
- 37-6
0 -6387
80760
- 37*2
0-6587
83280
- 36-7
0 -6787
85810
- 36'0
0 -7087
89600
- 35-2
0 -7208
91140
- 33-7
0-7228
91380
- 31-2
0-7248
91640
0
0 -7440
94070
+ 13-1
0-7518
95060
+ 16-3
0-7540
95330
+ 35-4
0 -7653
96760
Adopting the value for the specific resistance of pure mercury at
0° C., which has been recommended by the Board of Trade Electrical
Committee, viz., 94,070 C.G.S. units, we have reduced the observed
resistances of the mercury column at various temperatures to their
equivalents in resistivity in absolute units, and placed these numbers
against the observed resistances in the table above. As the specific
resistance of mercury has been so carefully observed by many
observers, we did not, for a moment, consider it necessary to attempt
a further determination of this constant. On plotting out these
values of the resistivity of mercury in the form of a curve in terms
of the corresponding platinum temperatures, we find the resistivity
curve has the form shown in fig. 1. It will be noticed that the
resistivity of the mercury decreases gradually from the point at
which the observations finished, viz., at +35° C., to the temperature
— 36° on the platinum scale. At this point the resistivity rapidly
decreases to about one-quarter of its value in falling from —36° to
— 50°, and this sudden change all takes place within the range of
about 14° of temperature. At the temperature of —50° on the plati-
num scale the resistivity curve again changes direction, and con-
tinues downwards in such a direction as to show that if produced
along the same line from the lowest temperature actually observed,
viz., —204° on the platinum scale, it would pass exactly through the
absolue zero of temperature on this scale, which is — 283° pt. It is
also interesting to note that the part of the curve which corresponds
to the mercury in the liquid state is almost exactly parallel to that
part of the curve which corresponds to mercury in the solid condi-
tion, although, owing to the difference in the absolute values of the
resistivities at these parts, the temperature coefficients as usually
defined are very different. In the solid condition between the tem-
peratures of —197-9° and —97°, the mean increase in resistivity is
80 Resistivity of Mercury at the temperature of Liquid Air.
FIG. l.
700,000'
13? -Eoo? -loo° o° +/oo
g
&£
&
$0,000'
80,000-
1
. 70,000-
*-* 60,000-
i
4
1
lOjOOO-
0-
-A
J
^
^
^^'''
~*7.. '
1° -£oo*° —loo-0 o-° +/oc
Temperature in Platinum Degrees.
S3'14 C.G.S. units per degree rise of temperature on the platinum
scale ; between — 108'4° and — 57'6° the mean increase in resistivity in
C.Gr.S. units per degree is 109*6 ; in the liquid condition between the
temperature — 35'2° and 0° the mean increase in resistivity in C.Gr.S.
units per degree is 83*2; temperature measurement being on the
platinum scale as above denned. It may be stated here that tem-
peratures defined by this platinum scale do not differ by more than
about 0'5° from the Centigrade scale down to temperatures of —100°,
but that the temperature of boiling liquid oxygen which, on the
Centigrade scale is denoted by —182°, is, on the platinum scale
Magnetic Permeability, fyc., of Iron at Low Temperatures. 81
derived from our standard thermometer, denoted by — 196'7°. This
would show, therefore, that the temperature coefficient as usually
defined is O000884 between —35° and 0°.*
These observations are specially interesting as giving additional
proof that in the case of a metal of known purity the variation of
resistivity, as the metal is continuously cooled, is such as to indicate
that it would in all probability vanish at the absolute zero of tem-
perature. In the case of mercury, we are able to obtain a metal in a
state of almost perfect chemical purity, and which, when continuously
cooled, passes into the solid condition under circumstances which are
entirely favourable to the prevention of stresses in the interior of the
metal, due to cooling. These measurements, therefore, afford a
further confirmation of the law which we have enunciated as a
deduction from experimental observations, that the electrical resis-
tivity of a pure metal vanishes at the absolute zero of temperature.
"" On the Magnetic Permeability and Hysteresis of Iron at
Low Temperatures." By J. A. FLEMING, M.A., D.Sc.,
F.R.S., Professor of Electrical Engineering in University
College, London, and JAMES DEWAR, LL.D., F.R.S.,
Fnllerian Professor of Chemistry in the Royal Institution,
&c. Received May 27,— Read June 11, 1896.
Although considerable attention has been paid to the changes
produced in the magnetic properties of iron, particularly its magnetic
permeability and hysteresis, at ordinary and at higher temperatures,
but little information has been obtained up to the present on the
behaviour of iron and steel as regards magnetic properties when
cooled to very low temperatures. By the employment of large
quantities of liquid air we have been able to conduct a long series of
•experiments on this subject, the results of which we propose here
briefly to summarise, leaving for a future communication fuller
details and discussion of the results. The experimental work has
consisted in making measurements, chiefly by ballistic galvanometer
methods, of the permeability and hysteresis loss in certain samples of
iron and steel, taken in the form of rings or cylinders. The first
experiments were concerned with the variation of the magnetic
permeability of .soft iron under varying magnetic forces, the iron
being kept at a constant low temperature, obtained by placing it in
liquid air in a state of very quiet ebullition in a vacuum vessel.
* This is in close agreement with the values obtained by Guillaurae, Mascart,
and Strecker for temperatures between 0°C. and +30° C.
82 Profs. J. A. Fleming and J. Dewar. On the
Experiments on Annealed Swedish Iron.
A cylinder of iron was formed by winding up a sheet of Saukey's
best transformer iron (Swedish).* The width of the strip was
4*895 cm., the thickness O0356 cm. ; three complete layers of the
sheet iron were used in forming the core. The area of cross-section
of the side of the cylinder so formed was 0'5229 sq. cm. The mean
diameter of the cylinder was 3*612 cm. This cylinder of iron was
placed in a clay crucible packed with magnesia, the lid luted on with
fire-clay, and the crucible then raised to a bright red heat in a forge,
after which it was allowed to cool very slowly. The iron cylinder was
thus carefully annealed out of contact with air or any material con-
taining carbon. This soft annealed iron ring was then wound over
with silk ribbon, and two windings of silk-covered copper wire placed
upon it ; the first or primary circuit consisted of 131 turns of No. 26
double silk-covered wire ; the secondary circuit consisted of 112 turns
of No. 36 silk-covered copper wire. The magnetising force to which
the ring is subjected when a current is sent through the primary coil
is measured by the value of 4<7r/10 x the ampere-turns per unit of
length of the mean perimeter of the ring, and this, in the case of the
present ring, reduces to the number 14'507 times the ampere current.
The magnetising force in absolute units is therefore very closely
given by the number obtained by multiplying the current flowing
through the primary coil in amperes by !4'5. The resistance of the
primary coil at about 15° C. was 0'92 ohm, and the resistance of the
secondary at the same temperature 8'98 ohms. The secondary
circuit of this ring coil or transformer was then connected through
appropriate resistances with a ballistic galvanometer, having a
resistance of 18 ohms. The primary circuit was connected through
suitable resistances and a current reverser with a circuit of con-
stant potential. By these arrangements it was possible to reverse
a definite current passing through the primary coils, and by observ-
ing the throw produced by the ballistic galvanometer, to calculate
the induction in the iron core. The galvanometer was calibrated by
reversing a known current passing through a long solenoid, in the
centre of which was placed a secondary coil of known turns and
dimensions, which was always kept in series with the secondary coil
of the transformer. In this manner a series of observations was
taken with gradually increasing magnetising forces. Before com-
mencing each series of observations, the ring was carefully demagnet-
ised by passing through the primary coil an alternating current,
which was gradually reduced in strength to zero, the ring coil being
thus brought into a magnetically neutral condition. An increasing
* This sheet iron was kindly given to us by Mr. K. Jenkins, to whom our thanks
are due.
Magnetic Permeability, CJT., of Iron at Low Temperatures. 88
series of primary currents was successively passed through the
primary coil and reversed, the throw of the ballistic galvanometer
being noted in each case. In the first set of observations the ring was
kept at the ordinary temperature of the air, 15° C., and in the
second set it was immersed in liquid air, and the following table
shows the results, both for the high and for the low temperature
observa/tions.
After taking a complete magnetisation curve at the ordinary tem-
perature, the ring was immersed in liquid air, bringing its tempera-
ture down to about —185° C., and a complete series of observations
taken again in the same manner, previously having first carefully
Table I.— Magnetisation Curve of Annealed Soft Iron (Sankey's
Transformer Iron).
At 15° C.
At -18G°C. (in liquid air).
Magnetising
force.
Induction.
Permeability.
Magnetising
force.
Induction.
Permeability.
H.
B.
p..
H. B.
1
fj..
0725
1000
1379
0-841
1000
1189
0-971
2000
2060
1-174
2000
1704
1-174
3000
2555
1-407
3000
2132
1-378
4000
2903
1-595
4000
2508
1 -595
5000
3135
1-886
5000
2651
1-840
6000
3261
2-145
6000
2797
2-10
7000
3333
2-440
7000
2869
2-58
8000
3101
2-99
8000
2675
3-35
9000
2687
3-83
9000
2350
4-47
]0000
2237
5-08
K'OOO
1968
6-27
11000
1754
7-05
11000
1560
8-99
12000
1335
9-72
12000
1234
12-35
13000
1053
13-11
13000
992
17-22
14000
813
17-90
14000
782
22-1
14400
652
21-35
14300
670
demagnetised the ring as described by an alternating current. The
ring was then taken out of the liquid air, allowed to warm up again
to the ordinary temperature, and another complete set of observations
taken at the ordinary temperature. In this manner a series of
eighteen complete sets of observations were taken, about half of them
being at lo° C. and half of them at — 185° C. In cooling the ring in
liquid air, it was found to be important to cool it slowly by holding
it some time in the dense gaseous air lying over the liquid air. If
suddenly plunged into liquid air the iron becomes hardened. It was
found that after the first five sets of observations, which were some-
84 Profs. J. A. Fleming and J. Dewar. On the
what variable, the annealed iron ring was brought into a completely
stable condition, in which the curve of magnetic induction plotted in
terms of magnetising force taken at the low temperature was different
from that taken at 15° C. by a perfectly constant amount, the observa-
tions at the low temperature always lying on one curve, and those at
the higher temperature always lying closely on the other curve. In
the diagram in fig. 1 the two magnetisation curves are shown, the
firm line curve being the magnetisation curve at 15° C., and the
dotted curve being the magnetisation curve taken at —185° C. in the
liquid air. The figures in Table I are the mean values obtained from
the curves plotted from the thirteen sets of closely consistent observa-
tions. These curves show that the permeability of soft annealed iron
is reduced when it is cooled to about 200° below zero, for the whole
range of magnetic forces between zero and 25 C.G.S. units. The
permeability curves for the two states are likewise similarly shown on
the same chart. The maximum permeability for this iron corresponds
with a magnetising force of about 2 C.Gr.S. units; the maximum
permeability at the ordinary temperatures for this iron is 3400, being
reduced to 2700 when the iron is cooled to the temperature of liquid
air. The percentage reduction in permeability becomes less as the
magnetising force is increased beyond or reduced below this critical
magnetising force. These experiments were repeated, as above
stated, many times very carefully with this ring of annealed soft
Swedish iron, and also with a second ring of the same kind, and
have invariably shown the same results, viz., that the permeability
of soft annealed iron is decreased by being cooled to this low tem-
perature within the range of magnetising forces from 0 to 25. It
will be seen that the highest induction reached in the case of this
iron is 14,500 C.Gr.S. units, corresponding to a magnetising force of
25. This iron is of very high magnetic quality, and is of the same
character as that which is much used for the construction of alterna-
ting current transformers in commercial use. *
A series of experiments was then made with the same transformer,
keeping the magnetising forces constant, but allowing the iron to rise
gradually in temperature up from the temperature of liquid air to
15° C. In these experiments the transformer was embedded in a
mass of paraffin wax with a platinum wire resistance thermometer
also embedded in the same mass in close contact with the ring coil.
The paraffin wax encasing the ring coil and thermometer having
been cooled down to the temperature of liquid air by immersing it in
a large bath of the liquid air, it was then lifted out and placed in a
vacuum-jacketed test-tube, so as to heat up with extreme slowness,
and a series of observations taken by reversing a constant magneti-
sing force at intervals, and observing at the same instant the tem-
perature of the ring coil as given by the platinum thermometer.
Magnetic Permeability, §c., of Iron at Low Temperatures. 85
FIG. l.
Magnetising force in C.G£. units.
I 234567 69 10 II 12 15 14 15 16 17 IB 19 20 21
14,000
WOO
12000
11,000
10000
g 8000
D
: 7,000
"Q
^ 6000
5000
4,000
3000
2000
1000
Permeability And Magnetic
in Soft Iron
at + 15 ° Centigrade.
\
\
0 500 1000 1,500 2,000 2,500 6,000 3,500 4,000
Scale of Permeability in C.G.S. units.
86 Profs. J. A. Fleming and J. Dewar. On the
The results of these observations are given in Table II, and these
observations are set out in the curve marked soft annealed iron in
fiff. 2.
Table II. — Variation of the Magnetic Permeability of Soft Annealed
Swedish Iron with Temperature.
Magnetising force = 177 C.G.S.
Temperature measured in platinum degrees by standard thermo-
meter PI.
Temperature. Permeability.
0° 2835
- 20 2815
- 40 2770
— 60 2727
- 80 2675
— 100 2622
-120 2560
-140 2497
-160 2438
-180 2381
—200 2332
The results show that as the temperature rises up from —185° C., or
— 200° on the platinum scale temperature, up to the ordinary tempera-
ture, the permeability of the soft iron for the particular magnetising
force selected increases perfectly uniformly, the curve of increasing
permeability with temperature being nearly a straight line.
In the next place, we have examined the hysteresis of the same soft
iron ring at different temperatures and for different maximum induc-
tions. These observations were carried out by taking a complete
series of hysteresis curves with the ballistic galvanometer, gradually
increasing the inductions from zero to 12,000. After the complete
hysteresis curves were obtained, their areas were carefully integrated
with an Amsler planimeter, and the values reduced so as to express
the hysteresis loss in watts per Ib. per 100 cycles per second, and
these values plotted in terms of the maximum value of the magnetic
induction per square centimetre of the iron core corresponding to
each particular hysteresis loss. Nothing would be gained by giving
the full details of all the observations by which these hysteresis
curves were obtained. They were exceedingly numerous, and the
tedious nature of the ballistic observations made it a matter of pro-
longed observation to secure the whole series necessary, but the final
results are shown in Table III. The curve in fig. 3 represents the
increase of hysteresis loss with induction, and the observations which
Magnetic Permeability r, cj-c., o/ Iron at Low Temperatures. 87
Fia. 2.
3,500
Relation of Permeability
to
Temperature.
-200-/90-I80-I70-I60-I50-I40-I50-I20-IIO-IOO-90-60-70 -60 -50-40 -50 -ZQ -10 0
Scale of Temperature (Platinum Degrees).
88 Profs. J. A. Fleming and J. Dewar. On the
i
$**
$
/
Hy
a
steresis
anke/s bes
'oss in s
t transforn
oft iron,
er iron)
/
/
/
/
X
^
/
2000
4,000 6,000 6,000
Induction in C.G.S. units.
t 0,000 12,000
Table III. — Hysteresis Loss in Soft, Annealed Swedish Iron in Watts
per pound per 100 cycles per second for various maximum Induc-
tions.
I. At +15°C.
II. At -185° C. (in liquid air).
f
Maximum
induction.
Hysteresis
loss.
B.
W.
844
0-0397
4026
0-4957
6743
1-062
9687
2-070
11618
2-632
8593
1-545
5516
0-823
Maximum
induction.
B.
688 '
3603
6185
9461
11916
Hysteresis
loss.
W.
0-02519
0-4246
0-949
1-907
2-658
were taken at ordinary temperatures are denoted by the small circles.
The observations for hysteresis loss which were taken at the tempera-
ture of liquid air are denoted by the crosses. It will be seen that
substantially the circles and the crosses lie on the same curve. The
results of these observations, therefore, show that there is practically
no change in the hysteresis loss in soft iron by cooling it to the tern-
Magnetic Permeability, <Jc., of Iron at Low temperatures. 89
perature of liquid air. If, instead of plotting the hysteresis loss and
induction, the ordinary logarithms of these quantities are taken
as coordinates, the curve, as shown in fig. 4, then obtained is
FIGK 4.
•4
-3
•2
^ •/
i '
Jt«
f*
| '&
1-2
AJ
7
<
/
/
\ -
Loga,
ithm
(ordi
iary)
aMfc
\imut
1 1nd
jctioi
A/
•m$
tyc/e.
V 6-
f 6-
2 6-
5 6-
4 J-
o 6'
o *
7
<y j-
9 4
O 4
/ 4-
\
It4t.
/
/
/
/
/
/
..
i
/
/
1
very nearly a straight line as far as the limit of an induction
of about 9000, and from the inclination of this line it is clear
that the hysteresis loss, W, in watts per lb, per 100 cycles is
found to be related to the maximum induction B in C.GLS. units
per square centimetre by the law W = -jgj BrM, or, if the hys-
teresis loss is reckoned in ergs per cubic centimetre per cycle -
W, then W = 0-002 Br56. These results are quite in accordance
VOL. LX.
90 Profs. J. A. Fleming and J. Dewar. On the
with certain conclusions of Messrs. Laws and Warren (see ' Pro-
ceedings of the American Academy of Sciences,' vol. 30, p. 490).
These observers made a series of experiments on a material which
was practically a very soft steel, and employing a differential watfc
meter, measured the hysteresis loss in the iron at varying and
increasing temperatures up to 600° or 700°. They found that the
hysteresis loss in this material did not begin to decrease sensibly
until about 150° C. ; after that it decreased regularly in accordance
with the simple linear function of the temperature. In one experi-
ment which they tried with the same material cooled to —78° C. in
solid carbonic acid and ether, they found no difference between the
hysteresis loss of this soft steel at that temperature and at the ordinary
temperatures. Our results, which have been carried to the much
lower temperature of liquid air, indicate that in the case of soft
annealed Swedish iron the hysteresis loss is not changed by cooling
from ordinary temperatures to the temperature of liquid air. As we
know that the hysteresis loss of soft iron decreases when the tem-
perature is increased, from the ordinary experience with transformers
in commercial use, the matter that requires further investigation is to
discover the temperature at which the hysteresis loss sensibly changes
and begins to diminish.
Experiments on Unannealed Swedish Iron.
We have also carried out a series of experiments • of the same
character with unannealed iron and steel. A ring coil was con-
structed of sheet iron of the same quality as that forming the core of
the soft iron transformer above described, but no special pains were
taken to anneal the iron, and as it was " hardened " in a magnetic
sense by being bent into shape, this difference in quality showed
itself in the magnetic observations. A ring coil was constructed of
the following dimensions : — The thickness of the strip was 0 031 cm.,
width of the strip 1/24 cm., the ring was formed by 23-| layers of
this sheet iron wound up closely into the form of a ring. The out-
side diameter of this ring was 4 cm., the inside diameter 2' 13 cm.,
the cross-section of the iron in the ring was therefore 0'9032 sq. cm.,
and the mean perimeter of the ring 9*62 cm. This iron ring was not
annealed in any way, but it was simply wound over with silk ribbon,
and then had placed upon it two coils of wire. The primary coil
consisted of 150 turns of No. 26 wire, having a resistance of
0'383 ohm, and the secondary coil consisted of 240 turns of No. 36
wire having a resistance of 8*092 ohms. As the diameter of cross-
section of the ring was not very small compared with the mean
diameter of the ring, it was necessary to calculate by a proper
integration the mean value of the mean magnetising force in terms
Magnetic Permeability, $c., of Iron at Low Temperatures. 91
of the current passing through the primary coil, and it was found
that the mean magnetising force to which the iron was exposed was
closely expressed by the value 20'219, multiplied by the ampere
current flowing through the primary coil. This coil had its second-
ary circuit connected* up to the galvanometer, as above described,
and a series of observations were taken with this coil by reversing a
constant magnetising current passing through the primary coil, and
observing the throw of the ballistic galvanometer connected with the
secondary circuit. The ring coil, together with the platinum thermo-
meter, was embedded, as above described, in a mass of paraffin wax,
and the whole mass, after having been cooled down to the tempera-
ture of liquid air, was slowly allowed to heat up again. Observations
were taken with two different magnetising forces over the range of
temperature from —185° C. up to the ordinary temperature, and
from the calculated induction in the ring determined for each mag-
netising force, the permeability was found corresponding to each
particular force and. temperature. The results of these observations
are given in Table IV, and are delineated in fig. 2, in the form of
two curves marked unannealed iron.
Table IV. — Variation of Magnetic Permeability of Unannealed '
Swedish Iron with Temperature.
Temperature measured in platinum degrees by standard thermo-
meter Pt.
Permeability.
Temperature.
0°
- 20
- 40
- GO
- 80
-100
-120
-140
-160
-180
-200
The results of the observations, as indicated in fig. 2 in the
curves marked Unannealed Iron, show that for this unannealed iron
the permeability increases as the temperature falls, and is exactly
the reverse in the case of the same quality of iron carefully annealed.
The difference, also, between the two materials is very marked
( —
Magnetising
force, 1'78.
Magnetising
force, 9-79.
917
1210
885
1212
857
1212
832
1208
913
1230
993
1240
1067
1255
1153
1265
1230
1280
12G2
1290
1272
1293
92 Profs. J. A. Fleming and J. Uewar. On the
at low temperatures. The soft annealed iron if cooled slowly to
— 185° C. recovers its original permeability when heated up again to
ordinary temperatures. The unannealed iron, however, after cooling
to the same low temperature, retains some of its increased perme-
ability when heated up again to 15° C. The unannealed iron cannot
be taken over the temperature range again and again with the same
definite permeability values at each recurrent temperature, as in the
case of the soft annealed iron. The unannealed iron is more or less
permanently changed in magnetic character every time it is heated
or cooled.
With this transformer, a long series of observations were taken to
determine the hysteresis loss corresponding to different inductions
when taken at the ordinary temperatures, and the temperature of
liquid air. The hysteresis cycles were taken with the ballistic
galvanometer over wide ranges of maximum induction, the trans-
former being alternately at the ordinary temperature and in liquid
air, but no constant magnetic condition could be obtained. In one
set of observations, at a given maximum induction the hysteresis loss
was increased when the transformer was raised in temperature, and
for another series of observations at the same induction it was
diminished. It is therefore impossible to make any definite state-
ment with regard to the magnetic hysteresis loss in this unannealed
iron ring coil at the two temperatures. The mere fact of immersing
the unannealed iron in the liquid air changes its magnetic qualities
to such a degree that it is no longer the same material, magnetically
considered, after, as before its immersion. One curious fact, however,
was noticed very soon with regard to unannealed iron, and that is,
that if the unannealed iron ring coil has a small magnetising current
passed through its primary coil, the secondary coil being connected
to the galvanometer, the sudden immersion of this ring coil into
liquid air invariably causes a deflection of the ballistic galvanometer,
even when the primary magnetising current remains perfectly con-
stant in value, thus showing a sudden and very large increase in the
permeability of the unanneaied iron. Whilst the iron is in the
liquid air it retains this increased permeability. If brought suddenly
out its permeability again diminishes, but not with equal rapidity.
This is partly accounted for by the fact that the iron is cooled with
immense rapidity when it goes into the liquid air, but it heats up
again much more slowly when it is brought out. The definite fact,
however, remains, which has been repeatedly observed, that the
cooling of this unannealed iron to a low temperature always increases
its permeability, as far as we know, no matter whatever may be the
magnetising force employed. One difficulty experienced in dealing
with unannealed iron is the fact that in taking it up to the high
magnetising forces, and by the process required to remove residual
Magnetic Permeability, $c., of Iron at Low Temperatures. 93
magnetism by the application of an alternating current, the iron is so
altered in magnetic qualities that it is impossible to repeat two sets
of observations under precicely similar circumstances. With regard
to the unannealed iron, it may be noted that if an ordinary magnet-
isation curve is taken up to very high magnetisation forces, and the
iron then demagnetised by the application of an alternating current
gradually reduced, the first magnetisation curve can never be
repeated exactly again on applying increasing magnetisation forces,
but a curve is obtained which lies slightly inside the first curve, and
which indicates that the permeability has been reduced. The sub-
sequent repetition of this process will give a series of curves which
occupy different positions, but which do not precisely repeat any of
them. Hence it is impossible to repeat at a constant temperature with
this unannealed iron exactly any magnetisation or permeability curve.
In the case of the annealed iron it is quite different. A. magnet-
isation curve can be obtained after having carefully de-magnetised
the iron, if this magnetisation is pressed up to nearly its limit and
the iron then de-magnetised by the application of an alternating
and decaying magnetising force, a second magnetisation curve can be
obtained on again applying an ascending magnetising force, but it
will not coincide exactly with the first curve. The annealed iron
can, however, be brought back into its original condition by dipping
it a few times into liquid air. Under these conditions, we have been
able to repeat as frequently as required the observations with the
annealed iron taken at the different temperatures. In the case of the
unannealed iron the changes produced in it by immersing it in the
liquid air and by magnetising and demagnetising it, are such as to
render it almost impossible to obtain results capable of precise
repetition, with respect to the hysteresis loss and permeability for
varying magnetising forces.
Experiments with Hardened Iron.
A third set of experiments were taken with a ring coil of the same
dimensions as the ring coil made of soft annealed transformer iron
first described. This third coil was constructed of the same sample
of Sankey's transformer sheet iron as the above described soft
annealed ring, but it was treated subsequently to its formation in
the following manner : —
A short piece of iron gas-pipe was made red hot in a forge ; the
ring coil, having been constructed, was dropped into the red-hot pipe,
and the ends of this pipe loosely plugged up with slag wool ; the red-
hot pipe was then covered ever with cinders, and the mass allowed to
cool. Under these conditions the ring coil was annealed in an atmo-
sphere of carbonic oxide and in contact with hot carbon ; the sheet
94 Profs. J. A. Fleming and J. Dewar, On the
iron was, therefore, under these circumstances, case-hardened, and
will be referred to as the hardened iron ring. Having been formed
into a transformer in the above-described manner, a long series of
observations were taken with this coil to determine its permeability
at different temperatures and with different magnetising forces. The
results of these observations are shown in the Table V below, and are
delineated graphically in the curves in fig. 2, marked Hardened Iron.
The results show in a remarkable manner that the iron so
treated undergoes a very considerable increase in magnetic perme-
ability, when it is cooled to the temperature of liquid air; for certain
magnetising forces the permeability at the lowest temperature
reached may be increased as much as five times. In this respect,
therefore, this iron presents in an exaggerated degree the same
qualities found in the unannealed iron.
Table Y. — Variation of Magnetic Permeability with Temperature of
Hardened Iron.
Temperature measured in platinum degrees by standard thermo-
meter PI.
Permeability.
Temperature.
H = 2-66.
H = 4-92.
H = 11-16.
H = 127-7.
0°
56-0
106-5
447-5
109-0
- 20
57-0
109 '5
476-0
108-5
- 40
58-0
114-0
506-5
109 0
- 60
59-0
119-8
540-0
110-5
- 80
62-5
132-5
575-0
111-0
-100
65-5
150-0
610-0
112-0
-120
69-2
169-3
645-0
112-0
-140
75-3
192 5
680-0
112-3
-160
89-5
236-0
717 -o
114-0
- ISO
107-5
338 -0
762-0
119-5
-200
132-0
502-0
823-0
124-0
Experiments with Steel.
We have also examined the behaviour of a ring coil made of steel
pianoforte wire. We have found in this case the curious result that
pianoforte steel behaves in the same manner as the annealed soft
iron; its permeability is decreased as the temperature is lowered.
The results of the measurements with this steel-core ring are shown
in Table VI, and graphically in the curves in fig. 2, marked steel.
Magnetic Permeability, $c., of Iron at Low Temperatures. 95
Table VI. — Variation of Permeability with Temperature.
Pianoforte SteeL
Temperature measured in Platinum degrees by standard thermo-
meter Pj.
Permeability.
Temperature.
- 0°
f
Magnetising
force, 7*50.
86-0
— >
Magnetising'
force, 20'39.
361-0
- 20
84-0
332-5
- 40
81-0
299-5
- 60
79-0
271-5
- 80
77-0
246-5
-1<)0
74-0
220-0
-120
71-5
193-0
-140
68-5
174-3
-160
67-0
163-0
-180
66-0
153-0
-200
64-5
144-0
We propose to continue the examination of the anomalous behaviour
so presented by iron in different states of hardening by examining in
the same way the changes of permeability in the case of several iron
rings of the same dimensions formed in the one case of soft annealed
iron, and in another case of the same quality of iron hardened, and in
the remaining cases using steel of known composition at different states
of temper. We desire to add that in the conduct of this research we
have been under great obligations to Mr. J. E. Petavel for rendering
us very efficient assistance in taking the exceedingly tedious ballistic
galvanometer observations, and in reducing them when taken.
Magnetic Permeability, $c., of Iron at Low ; Temperatures. 95
Table VI. — Variation of Permeability with Temperature.
Pianoforte Steel.
Temperature measured in Platinum degrees by standard thermo-
meter Pj.
Permeability.
Temperature.
- 0°
- 20
- 40
- 60
- 80
-100
-120
-140
-160
-180
-200
We propose to continue the examination of the anomalous behaviour
so presented by iron in different states of hardening by examining in
the same way the changes of permeability in the case of several iron
rings of the same dimensions formed in the one case of soft annealed
iron, and in another case of the same quality of iron hardened, and in
the remaining cases using steel of known composition at different states
of temper. We desire to add that in the conduct of this research we
have been under great obligations to Mr. J. E. Petavel for rendering
us very efficient assistance in taking the exceedingly tedious ballistic
galvanometer observations, and in reducing them when taken.
Magnetising
force, 7*50.
N
Magnetising
force, 20-39.
86-0
361-0
84-0
332-5
81-0
299-5
79-0
271-5
77-0
246-5
74-0
220-0
71-5
193-0
68-5
174-3
67'0
163-0
66-0 -
153-0
64-5
144-0
VOL. LX.
Dr. C. Chree. Observations on Atmospheric
" Observations on Atmospheric Electricity at the Kew Observa-
tory." By C. CHREE, Sc.D., Superintendent. Communi-
cated by Professor G. CAREY FOSTER, F.R.S. Received
May 11,— Read June 4, 1896.
TABLE OF CONTENTS.
PAET I.
The Measurement of Potential in Theory and Practice.
§§ PAGE
1 Historical and descriptive , 96
2 — 3 Interpretation of electrograph records 98
4 Selection of stations , 99
5 — 6 Comparison of results at the different stations 100
7 — 9 Eatio of readings at different stations, at different times, and under
different meteorological conditions 102
10 Comparison of water-dropper and portable electrometer 106
11 Defects in instruments 108
12 Checks recommended 109
PAET II.
Application of Results to Theories of Atmospheric Electricity. ,
13—15 Theories of Exner and of Elster and G-eitel 110
16 Method of treating Kew observations 112
17 — 19 Anticipation of some objections : want of uniformity in conditions as
to wind, and cloudiness; proximity to London 112
20 Tables of results, including particulars as to potential, vapour density,
humidity, sunshine, temperature, barometric pressure, and wind
velocity 114
21 Analysis of preceding tables according to voltages at base station .... 123
22 Further tables, each containing analysis according to magnitude of
some one meteorological element. . . . , 125
23 Discussion of possible influence of vapour density 128
24 relative humidity 128
25 sunshine 128
26 temperature 129
27 barometric pressure 129
28 wind velocity 129
29 — 30 General summary of bearing of results on theory 130
PAET I.
The Measurement of Potential in Theory and Practice.
§ 1. An electrograph belonging to the Meteorological Office has
been in operation at Kew Observatory, with interruptions, since 1861.
The results obtained in the early years of its existence were dis-
Electricity at the Kew Observatory. 97
cussed in 1868 by Professor Everett,* and the results obtained in
1880 were discussed in 1881 by my predecessor, Mr. Whipple.f
Nearly two years ago, with the approval of the Kew Observatory
Committee and the Meteorological Office, I commenced an investiga-
tion intended as preliminary to a consideration of the expediency of
further publication of the electrograph records.
My first object was to find out whether definite quantitative
measurements of potential could be derived from the electrograph
curves. To aid in this investigation observations have been made
at several spots near the Observatory with a portable electrometer,
by White, of Glasgow, whose scale value was determined at Uni-
versity College by the kind assistance of Professor Carey Foster.
To render intelligible the bearing of these observations on the
question, a brief description is required of the nature and position of
the electrograph. J It consists essentially of a water-dropper and a
quadrant electrometer. The water is held in a can, some 14 inches
high and 15 inches in diameter, supported on three insulators of the
Mascart pattern. From the can a tapering tube, resting on a fourth
insulator, projects through a hole in a window facing the west. The
end of the tube whence the water issues is 4^ feet from the west wall
of the Observatory, and 10 feet above the ground. The stream of
water is regulated by two taps in the long tube. From the water-
dropper an insulated wire passes to the needle of the quadrant
electrometer. One pair of quadrants are kept at a given positive
potential, the other pair at an equal negative potential, by means of
a battery of 60 cells in series whose centre is to earth. The needle
suspension carries a mirror, and light reflected from it produces a
curve on photographic paper which is wound round a cylinder driven
by clock-work. The position of the base line answering to the earth's
potential — treated as zero — is obtained by putting the electrometer
needle to earth, twice at least for each curve. Of late years the value
of the curve ordinates, in volts, has been obtained from time to time
by connecting the electrometer needle and one terminal of the
portable electrometer, and varying their joint potential by means of
^n electrophorus. Simultaneous readings are taken of the curve
ordinate and the portable electrometer.
If the ideal were attainable, the stream from the water-dropper
should break up exactly at the end of the tube, and be always
sufficiently copious to ensure the immediate picking up by the can
and the electrometer needle of the potential existing in the air at the
spot in question.
* ' Phil. Trans.' for 1868, p. 347.
t ' B. A. Keport,' vol. 51, p. 443.
.J (July 28.) Some alterations have been effected since the above was written
i 2
98 Dr. C. Chree. Observations on Atmospheric
Interpretation of Electrograph Record.
§ 2. The first question is : supposing the apparatus perfect, does
the electrograph supply information as to the potential anywhere
except at the spot where the stream of water breaks into drops ? To
answer this question, one has to consider the influence of the environ-
ment, notably the proximity of a lofty building.
An investigation into this point was made ten years ago by Pro-
fessor Exner, of Vienna, who found the equipotential surfaces near
a building much deflected from horizontally. His results indicated
apparently that for practical purposes the whole building might be
regarded as possessing the earth's potential. Whilst it was antici-
pated that Exner's conclusions would hold good of Kew Observatory,
it appeared prudent as a check to take observations with the portable
electrometer, at a series of points in a vertical plane perpendicular
to the west wall near the water-dropper. Observations were taken
at heights of 3, 6, and 9 feet from the ground, which possesses, it may
be explained, a slope away from the building. The base line, starting
at the Observatory wall, terminated 57 feet away in a parallel wall
11 feet high, belonging to a much lower building. The observations
were repeated on several days, but one example will suffice. The
potential measurements are in volts, the distances from the Observa-
tory wall in feet.
Table I.
Observations on November 6, 1894.
Mean
Distance from wall 3 6 12 18 24' 30 36 42 48 54 potential.
Potential at height 3 feet .. 4 6 18 38 48 46 34 24 16 6 26
6 „ .. 8 18 40 58 88 84 76 68 52 22 56
„ 9 „ .. — 28 44 76 102 120 120 108 68 36 78
In forming the means in the last column the results at 3 feet from
the Observatory wall were omitted. The readings were uncorrected
for variations of potential during the interval occupied by the obser-
vations.
So far as they go, the results are clearly confirmatory of Exner's.
They show that the influence of a tall building in pulling down the
potential extends to a considerable distance.
§ 3. The large dependence of the electrograph records on the im-
mediate environment of the water jet complicates matters, but this
need not prove a serious obstacle if the conditions allow us to regard
the problem as one of statical electricity, in which influencing bodies
are either stationary or at a distance. On this hypothesis, simulta-
neous potentials at any two neighbouring points would stand to one
Electricity at the Kew Observatory. 99
another in a practically constant ratio, a function only of their
geometrical coordinates.
If once this ratio were determined, one could deduce the potential
at either point from that observed at the other. Regarding the spot
where the water jet breaks up as one of these points, and selecting
for bhe other a spot sufficiently distant from the building, one
could deduce the potential gradient in the open, i.e., the increase in
voltage per unit of height above the ground. This point of view was
apparently acted upon by Exner,* and by Elster and Geitel.j In
both instances the existence of corroborative evidence is referred to,
but I am not aware that particulars have been published. It would
also appear that Exner and Elster and Geitel directed their attention
mainly, if not exclusively, to clear quiet days.
There being no limitation to the use of the Kew electrograph, it
appeared advisable not to restrict the investigations to days of a
special kind, or to a particular season of the year.
Selection of Stations.
§ 4. It appeared desirable to compare the potential at more than
two stations, so as to ensure a sufficient variety in the surroundings.
I shall distinguish the stations selected by the letters A, B, C, D, E,
F. Of these A is the flat top of a stone pillar, 3 j feet high, in the
Observatory garden, about 56 yards from the Observatory; it is
surrounded by a frequently mown grass lawn. B is the top of a
temporary wooden stand, 6f feet high, and only 3£ feet from the west
wall of the Observatory. C is the centre of a flat plank supported
3J feet above the ridge of a wooden building, situated about 100 feet to
the south-west of the Observatory ; it is 18 feet above the ground. D
is on the south side of a stone parapet, 2£ feet high, encircling the flat
roof of the Observatory ; it is 37 feet from the ground. E is the top
of a camera stand, 5-g- feet above the Observatory roof, and 17 feet to
the east of the central dome. F is the top of a stand on the roof —
used for testing anemometers — level with the cups of the standard
anemometer, from which it is distant about 17 feet to the north; ii is
57 ft. et above the ground.
The observations were taken with the portable electrometer, and,
as the burning end of the fuse was at a height of some 12 to 16 inches
above the base of the electrometer, an addition of, say, 1£ feet requires
to be made to the altitudes of the several stations to get the height
from the ground of the spot whose potential was measured.
A was the only station that could be regarded as practically unin-
fluenced by the neighbourhood of a building, and even in its case we
* ' Wien. Sitz.,' vol. 98, 1889.
f ' Wien. Sitz.,' vol. 101, p. 703, 1892.
100
Dr. C. Chree. Observations on Atmospheric
have the influence of a massive stone pillar some 2J square feet in
section. A calculation of the potential gradient which regards the
observations at A as referring to a spot 60 inches above the ground
in the open is certain to give an under- estimate. As it is impossible,
however, to dispense with a support of some kind, and the presence
of the observer is also a disturbing influence, no exact allowance can
be made for this.
There have been four principal series of observations. In the first,
occupying part of November and December, 1894, observations were
taken, when practicable, once a day at stations A, B, C, D, and latterly
at E also. In the second series, during part of March and April,
1895, observations were usually taken about 10.30 A.M. and 4.30 P.M.
at each of the stations except F. The third series, during part of
June and July, 1895, closely resembled the second; and the only
material difference in the fourth was the substitution of station F for
station D.
No observations were taken on Sundays or on Saturday afternoons.
The observations were taken in a fixed order, and, thanks to the skill
of the observer, Mr. E. G. Constable, a complete set of readings
occupied only some seven or eight minutes. The time scale of the
electrograph curves is far from open, and for this and other reasons I
have judged it best not to attempt to reduce the readings with the
portable electrometer to a common instant.
Comparison of Results at the different Stations.
§ 5. I have taken A as base station, and have found the ratios
borne to the individual readings there by the corresponding readings
at the other stations.
Let rA, rE represent corresponding readings at A and B, and let
_ 1
n
B/A
where 2 denotes summation for a series of n observations. Then r
maybe called the mean value of the ratio for the series of observations.
Also let us apply the term percentage deviation of the ratio from its
mean to the quantity
X100,
B/A
in which the terms in the numerator are taken irrespective of sign.
Table II gives the extreme and mean values of the ratios during
each series of observations, excluding three or four occasions when
negative potentials were met with.
Electricity at the Kew Observatory.
Table II.
101
Series of
Number of
observa-
observa-
tions*
tions.
rs/r^.
, — — *- — ^
rclr\.
rD/r^.
Max. Min. Mean.
Max. Min. Mean.
Max. Min. Mean.
I.
25
0-38 0-17 0-26
3-05 I'll 2-22
3-33 1-46 2-41
II.
45
0-54 0-16 0-29
2-32 1-40 1-78
4-52 1-46 2-28
III.
31
0-50 0-17 0-27
2-29 1-00 1-70
3-67 1-11 2-14
IY.
23
0-41 0-09 0-22
2-86 1-33 1-92
Series of
Number of
observa-
observa-
tions.
tions.
**fi/rA.
n?/rA.
Max. Min. Mean.
Max. Min. Mean.
I.
25
4-95 2-46 3-12
,
II.
45
6-30 1-74 2-68
__ __
III.
31
4-33 1-11 2-51
IV.
23
4-73 2-05 2-87
8-34 2-71 4-53
In series I there were only twelve observations at station E. In
series III the mean ratios for the higher stations are depressed by
one abnormally low reading. The means in the different series
vary, but the differences are too small fco warrant any positive con-
clusion. They indeed suggest the possibility of the potentials at the
higher stations being relatively somewhat higher in winter than in
summer, but this may arise from a slight want of uniformity in the
procedure followed at the different seasons.
The departures of the maxima and minima in Table II from the
means are considerable, but the number of instances in which the
departures from the mean are large is in reality small. This will be
seen by reference to Table III, which gives the percentage deviations
of the ratios from their means, treating each series of observations
separately.
Table III.
Percentage Deviations from the Means.
Series of
observations.
fn/r*
rc^.
r»rA
I.
14
14
15
15
II.
19
10
19
21
—
III.
19
11
20
20
—
IV.
28
13
—
16
20
102
Dr. C. Chree. Observations on Atmospheric
The irregularity in rB/rA may be due in part to the slightly unsteady
character of the stand forming station B. The potentials at B were
also much the lowest, so that errors of reading were there of most
importance. At the highest station, F, the variations occurring in
the potential sometimes made accurate measurements difficult.
§ 6. To give a clearer idea of the degree of uniformity shown by
Table III, I give in Table IV the extreme and mean readings at the
several stations, omitting, as in Table II, occasions of negative
potential.
Table IV.
Readings in Volts at the several Stations.
Series of
observations.
A.
Max. Min. Mean.
264 104 158
708 50 206
174 27 100
830 29 249
B.
C.
Max. Min. Mean.
66 22 40
215 15 58
45 6 27
115 12 50
Max. Min. Mean.
552 120 352
1320 81 364
306 27 171
1452 52 476
I.
II.
III.
IV.
Series of
observations.
I).
E.
F.
r ^
Max. Min. Mean.
648 152 385
1464 122 455
354 30 210
Max. Min. Mean.
776 264 524
1688 ' 182 531
498 30 246
1785 93 662
Max. Min. Mean.
2362 122 1032
I.
II.
III.
IV.
On one exceptional day the potential at A varied from —1200 to
+ 1290 volts in less than forty minutes; at station F it varied from
—2424 to over +4000 volts in about the same time.
Constancy of Ratios during the Day.
§ 7. Table V gives the mean values of the ratios for the forenoon
and afternoon observations, treated separately, during those days
when there were readings at both 10.30 A.M. and 4.30 P.M. The days
available numbered 17, 10, and 9 respectively in the second, third,
and fourth series of observations. The headings " A.M." and " P.M."
distinguish the forenoon and afternoon observations.
In each case treated in table V the mean value of the potential for
the forenoon was considerably higher than that for the afternoon.
Thus, at station A the ratio of the forenoon to the afternoon mean
potential — for those days only on which there were both forenoon
Electricity at the Kew Observatory.
Table V.
Forenoon and Afternoon Ratios.
103
Series of
observa-
tions.
»*B/A.'
**C/A.
f * •>
**D/A.
'E/A.
!5_A'
A.M. P.M.
A.M. P.M.
A.M. P.M.
A.M. P.M.
A.M. P.M.
II. ! 0-29 0-28
1-82 1-83
2-24 2-21
2 '62 2-57
III. j 0-24 0-33
1 '75 1 -52
2 -16 1 -87
2-57 2-17
IV.
0-22 0-23
1 -96 1 -88
— —
2 -76 2 -87
3 -99 4 -46
and afternoon observations— was T37 in series II, T23 in series IU,
and 1*48 in series IV.
The difference between the mean potentials at the two hours on
the specified days being so large, we may reasonably suppose that if
any two other hours had been selected results would have been
obtained showing a degree of accordance similar to that in Table V.
The degree of accordance in the case of series II is truly remarkable,
and in series IV, considering the smaller number of observations, it is
but little inferior. If series III stood alone, we might suspect that in
the afternoon the potential fell off more at the higher stations than at
the lower, and this may of course be a true phenomenon of the season,
midsummer, to which that series belongs.
Possible Dependence of Ratios on the Weather.
§ 8. It is conceivable that under one regular set of climatic condi-
tions the potentials at the higher stations might relatively to the
lower be either abnormally high or abnormally low. To test this
point, the observations in each series Kave been divided into sets,
according to the value of such a ratio as rE/rA. Attention has been
confined to series II, ill, and IV, as in series I the times of observa-
tion were less regular ; but the forenoon and afternoon observations
in series II and III have been considered separately.
Supposing the number of measures of, say, rE/rA available in any
one instance to be 2n or 2n + l, the n cases in which the ratio is
largest form one set, the n cases in which it is smallest the other.
For each of these sets the corresponding mean values of certain
meteorological elements have been calculated, the data for the indi-
vidual times of observation being derived from the self-recording
instruments employed in the Observatory. The figures as to aqueous
vapour and humidity have been deduced from, the thermograms, with
the aid of a modification of Glaisher's table, compiled by the Meteoro-
logical Office.
104 Dr. C. Chree. Observations on Atmospheric
By " sunshine in hours " is meant the number of hours of sunshine
measured by the Campbell-Stokes recorder up to the time of observa-
tion. The data under this head have been limited to the most sunny
series of observations, viz., II and III.
The results are exhibited in Table VI, which shows also the
maxima and minima values of the meteorological elements observed
during the several sets of n observations.
There is in Table VI no uniform and conspicuous connexion
between the value of rE/A, or rF/A, and the corresponding value of any
one of the meteorological elements considered. In the case alike of
barometric pressure and temperature the second mean — answering
to the n lowest values of rE/A or rF/A — is higher than the first in five
instances out of six. The differences between the two means are
generally, however, so small that the phenomenon may be purely
accidental. In the afternoon observations of series II there is a
somewhat conspicuous association of a low value in rE/A with a high
value of previous sunshine ; but in series III there is no trace of
such a phenomenon.
The question whether there may not be certain occasional types of
weather, whose influence is masked in such a table as VI, which are
associated with either a high or a low value of the ratio rE/A, remains,
I think, open. Evidence is in my hands which leads me to believe
that during a low ground fog the potential gradient as a rale is
decidedly higher near the ground where the fog is thick than higher
up where the fog is slight.
Summary of Results at Different Stations.
§ 9. The conclusion I am disposed to draw, though I regard it as
only a probability, is that such general phenomena as diurnal or
annual variation of potential near the ground in the open may be
deduced with fair accuracy by applying a constant factor to the
records of a portable electrometer, employed regularly at a fixed
point on the Observatory roof or near its walls. It must be remem-
bered, however, that all six stations were comparatively close together,
and that the equipotential surface passing through the highest station
would be in the open perhaps only 14 or 15 feet above the ground.
There is thus no evidence to warrant the deduction of conclusions
for a spot a mile or two away or a few hundred feet above the ground.
On the trustworthiness of individual results deduced by means of
a constant factor, one would not, after inspecting Tables II and III,
be disposed to place much reliance. This question can hardly, how-
ever, be settled satisfactorily unless one have apparatus for taking
the observations at the different stations absolutely simultaneously.
The largest departures from the means in Tables II and III are
Electricity at the Kew Observatory.
105
II
'
.S'S «o a
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jgrHrH
rH 10
OS TO
CO CO
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rH rH '
^O O 00 00
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OS O »O iO rH rH
rP X (N 10 OS O rP TO X OS OS l>
*"H rH rH rH rH
rP O rHrP lO TO rPrP rH O rHO
O — I l> TO TO rP (M t>. QO OS OS rH
rpcq !N!M rH<M <M(M iH(N (MrH
s^
a TO CO OS CO
OS t* rH TO
^ rH rP CO O
S v£^ 10 CO CO
»pp 'T1^ ^^ "*(?1
10 CO COCO TOTO TOTO
OSX rH(N i>O OO
t>. TP OS
, OS CO X
<N (M TO (N TO
O <N OS X J>
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8.9
W
gQO
<N
rS O
CO CO
00
CO
00 OS
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xp X OS N
IO CO 1O CO
rP 10 X CO X CO
JOS X OS X
TO <M rH CO CO l>
rH CO X C^l J>» O
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rH O
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9 T1
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§ I
Foren
an
afterno
106 Dr. C. Chree. Observations on Atmospheric
doubtless due in great part to changes occurring whilst the observa-
tions were in progress.
Possible Influence of Pattern of Instrument.
§ 10. The conclusions in the previous paragraph refer as yet only
to the portable electrometer. They can be extended to the electro-
graph records only if we are able to show that a fairly uniform
ratio exists between the potential obtained with the water-dropper
at a fixed station and that obtained with the portable electrometer at
one or other of the stations A to E.
The position of the water-dropper was maintained undisturbed,
barring accidents, throughout the observations. It thus suffices to
compare the curve readings with the corresponding ones with the
portable electrometer at station A. The curves were accordingly
measured at the mean times of each set of observations. The ratios
of the individual readings to those at station A were calculated,
and results obtained analogous to those in Table II. It will suffice
for our present object to consider the results analogous to those in
Table III.
Table VII.
Percentage Deviations from the Means (Electrograph/Portable).
Series of observations.
*!. II. III. IT.
Percentage deviations 28 30 35 28
The spot where the jet breaks up resembles B more closely than
any other station, and shares its low potential. Further, the electro-
graph curves are read to the nearest 5 volts only, so that uncertainties
in the reading are even more important than with the portable, read to
the nearest 1 or 2 volts, at station B. Thus, the results in Table VII
are, at least, not conspicuously worse than those in Table III. As a
matter of fact, the results in Table VII were, I believe, somewhat
prejudiced by a variation in the water jet throughout the day (see
§ 11). Supposing this defect removed, the evidence points to the
conclusion that the diurnal, and possibly the annual, variations got
out with the water-dropper situated in the Observatory, and the
portable electrometer at station A, may be expected to be in good
accord, assuming the conditions under which each instrument works
to be maintained uniform.
Attention was also directed to the possibility of the two different
patterns of instrument being differently affected by the same climatic
conditions. Each series of observations — the forenoon and afternoon
observations of series' II and III being treated separately — was
Electricity at the Kew Observatory. 107
arranged in descending order of some one meteorological element. Sup-
pose there to be 2n or 2n + I observations in the series (or half series) «
the mean values of the ratios borne by the electrograph readings to
the corresponding ones with the portable electrometer at station A
were calculated for the first n and the last n instances separately.
Supposing r1} r2, and r to denote the mean ratios for the first n, the
last n, and the whole 2n (or 2n + l) observations, then
i{0-i-ra)/r}xioo
may be regarded as the average percentage deviation of the two
groups from the mean. Table VIII gives the value of this quantity
in the case of the three meteorological elements from which a differen-
tial effect was most feared.
Table VII T.
Value of M0-i-r2)/r} x 100.
Meteorological element considered.
Times of
observations.
observations.
Vapour
density.
Sunshine.
Wind
velocity.
I
Day
-15
- 8
" 1
Forenoon
Afternoon
-12
+ 1
+ 8
4- 4
+ 8
+ 12
m {
Forenoon
Afternoon
-20
-15
+ 14
+ 15
+ 22
-16
IV
Day
-15
< OJ-
A plus sign denotes that when the meteorological element in
question was above its mean the water-dropper was more than usually
effective, relative to the portable electrometer ; a minus sign implies
the contrary.
The evidence in the case of wind velocity is so contradictory that
we can safely assume that no uniform differential action exists.
In the case of the two other elements the evidence is more consistent,
and it is possible that a small differential action may exist. It looks
as if much moisture, when not counterbalanced by a contrary action of
sunshine, tends slightly to pull down the reading of the water-
dropper relatively to that of the portable electrometer. The pheno-
menon, supposing it to exist, might be ascribed to a loss of efficiency
in a water jet when the vapour in the air increases, and a similar loss
in a flame collector during bright sunshine. But an influence at least
as likely is that of moisture, during damp weather, on the insulation
of the electrograph.
108 Dr. C. Chree. Observations on Atmospheric
Defects in Water-dropper and Portable Electrometer.
§ 11. Both instruments aim at communicating the potential at a
fixed point in the air to an insulated conductor by detaching from a
mass in electrical connexion with the conductor a continuous succes-
sion of small elements. It is at least doubtful whether either instru-
ment can ever fully accomplish its object. If the object were so far
accomplished that a constant fraction of the true potential were
recorded, the deficiency of this fraction from unity would hardly be
of primary importance in dealing with diurnal or annual variation ;
but if the fraction has itself a diurnal or secular variation it is a very
different matter.
In the water-dropper a uniform state of insulation of the water-
can, electrometer needle, and connecting wire is not easy. Absolute
insulation, when a voltage runs up to hundreds, is a somewhat ideal
state of perfection. When the insulation is indifferent, the recorded
may fall far below the true potential. The water jet, so to speak, is
running up the potential, leakage from the can, wire, &c., running it
down. The resultanfc effect depends on a variety of things, e.g., the
rate at which the air potential is changing and the supply of water
particles. Unless the potential is unusually steady, and the insula-
tion exceptionally good, one may expect higher potential records with
a copious jet than with a restricted one.
In the portable electrometer there' is similarly some ground for
expecting the potential recorded to be influenced by the rate of com-
bustion of the fuse.
The uniformity of the disintegrating mass may also be of import-
ance. With a water-dropper there ought not to be much uncertainty
on this ground, but as electrometer fuses are articles of commerce
uniformity in their material and condition is less easily ensured.
There is a final source of uncertainty common to the two instru-
ments as commonly used. With the water-dropper the spot where
the jet breaks up is apt to be slightly influenced by variations in the
water pressure. When the issuing jet makes as usual an angle with
the wall of a building, the consequences, as appears from Table II, are
likely to be appreciable. It was a recognition of this fact that led to
the taking of the observations with the portable electrometer at two
nearly fixed hours, the afternoon one when the can was nearly full,
the forenoon one when it was about half empty.
The corresponding defect with the portable electrometer is the
burning down of the fuse. When the fuse is used in a vertical
position, the height of the spot whose potential is being measured
diminishes as the fuse burns, and with the height the potential falls
off.
No direct comparison of the readings of the two instruments at one
Electricity, at the Kew Observatory. 109
and the same spot was attempted during the observations, as it
seemed undesirable to interrupt the continuity of the electrograph
records. All that § 10 shows is that during any one series of observa-
tions the fractions of the true potential picked up by the two instru-
ments stood to one another in a fairly constant ratio. The presump-
tion, certainly, is that neither fraction altered much throughout the
few weeks covered by any one of the four series of observations.
It is, however, I regret to say, perfectly certain, from the data on
which § 10 is based, that one at least of the two instruments varied
very considerably in the course of a year and possessed a,n appre-
ciable diurnal variation.
§ 12. On the discovery of these defects it became not only justifi-
able but necessary to subject the water-dropper itself to direct
experiments. These have led to my proposing certain alterations
which are now in process of execution. They aim at bringing the
water-can and electrometer close together, and at maintaining a
more uniform water pressure than heretofore.
It appears also desirable to check the working of the apparatus in
some way jinvolving the arrival at exact numerical results. The
following operations A, B, C will, it is hoped, prove sufficient. The
operation C need not be performed so frequently as A or B.
A. Charge the quadrant electrometer needle to a high potential,
and observe the rate of leakage over a fixed range by timing the
motion of the spot of light across a scale with —
(1) the wire connexion to the water-can complete, but the jet not
flowing ;
(2) the wire connexion broken at the can ;
(3) the wire connexion broken at the electrometer.
B. As a substitute, or as subsidiary to A. Connect a portable
electrometer to the water-can, and, with the jet flowing, observe the
potential recorded by the portable, when —
(1) the can is connected as usual to the quadrant electrometer;
(2) the connexion is broken at the quadrant electrometer ;
(3) the connexion is broken at the can.
C. Take a sufficient number of observations at a fixed station out-
side with a portable electrometer, at or near two fixed hours a day,
so chosen that at one hour the can is almost full, whilst at the other
it is at least half empty.
The use to be made of the results is obvious.
I should also recommend any one using a portable electrometer to
test its scale value from time to time by comparison with an absolute
electrometer or a large battery of constant cells. It is well to lay in
a new stock of fuses before exhausting one's supply, and to compare
the old and new fuses by taking observations in rapid succession with
samples of the two at a fixed station.
110 Dr. C. Chree. Observations on Atmospheric
PART IT.
Application of Results to Theories of Atmospheric Electricity.
§ 13. It seemed desirable to consider what bearing the special
experiments might have on the general facts and theories of atmo-
spheric electricity. In this investigation special attention has been
given to the possible influence of aqueous vapour on electrical
potential, on account of the important researches of Exner, and of
Elster and Geitel.
Theories of Exner and of Elster and Geitel.
§ 14. Exner has advanced the view that the potential gradient in
the open, dV/dn in his notation, and the density q0 of aqueous vapour
simultaneously present in the atmosphere, are connected by a formula
dV/dn = constant -4- (l-f &gr0),
where k is apparently a constant, the same at all places and at all
seasons of the year. Exner, I believe, limited his observations, and
presumably the application of the formula, to days comparatively
quiet and free from clouds. To test the formnla he arranged his
observations in groups, according to the amount of vapour present,
and compared the mea.n vapour density — measured in grams per
cubic metre — with the mean potential gradient, measured in volts
per metre of height above the ground. In the ' Wien. Sitz.,' Bd. 99,
p. 618, he gives a table including results from Vienna, Wolfenbiittel,
St. Gilgen, and India, in which the vapour densities vary from 1*7
to 23'5. The table unquestionably shows a diminishing mean
potential gradient accompanying an increasing mean vapour density.
For values of q0 from 12'4 and upwards, however, — including all the
Indian and most of the St. Gilgen observations — the change in dV/dn
is somewhat small and irregular, An earlier, and somewhat similar,
but less extensive table by Exner will be found on p. 434 of ' Wien.
Sitz.,' Bd. 96.
For information as to Elster and Geitel's work I am mainly indebted
to a long paper by them in the ' Wien. Sitz.,' Bd. 101, p. 703, 1892.
During 1888-91 they took an extensive series of observations on
quiet days at Wolfenbiittel. If I follow their explanations, they took
eye observations some ten times a day with an electrometer, in which
flame from a lamp acts as collector, and deduced the mean value of
the potential gradient dV/dn for the day. They compare these
potential gradients grouped according to the value of the vapour
density with Exner's formula, taken to be
(dV/dn) (in volts per metre) = 1410/(l-fl-15g0),
Electricity at the Keiv Observatory.
Ill
where q0 is measured as above in grams per metre. They give an
abstract of the results on their p. 742, in the shape of a table which
I reproduce.
Elster and Geitel's Table III (loc. cit., p. 742).
?o =
1-6
1-9
2-5
3-7
4-6
5-6
6-5
7-6
8-4
9-4
10-6
13-5
dVldn (observed) =
502
430
400
318
252
137
184
148
112
115
118
121
„ (calculated) =
496
442
364
268
224
189
166
145
133
119
107
85
It would appear that Elster and Geitel, like Exner, found large
departures from the mean dV/dn of a group amongst its individual
members.
§ 15. Elster and Geitel next proceed to investigate a possible con-
nexion between the potential gradient and the intensity of that species
of solar radiation which dissipates a negative charge on an insulated
sphere of polished zinc. If I understand them rightly, they measured
the mid-day intensity J of this radiation, and compared the potential
gradient with several formulae in which the variable was either J or
J/, where / is a " Beleuchtungsf actor," equal apparently to (possible
hours of sunshine) /12. Taking a formula dV/dn = 110 + 360a~J,
where log a = O'OIOO, they give the following comparison of the
results of observation and theory : —
T
2'9
5-8
9-1
21-4
58'8
77-1
113-7
121-9
181-3
194-5
268-4
dVldn (observed) =
447
430
368
325
198
181
138
126
120
106
102
„ (calculated) =
447
425
402
330
203
171
136
132
116
114
111
The agreement seems better than in the case of Exner's formula,
and Elster and Geitel seem strongly inclined to regard ultra-violet
radiation as the direct cause of variations of potential on normal qniet
clear days. They consider apparently that there are only two defective
links in the chain of evidence, viz. : —
(1) absolute proof that the earth is electrified negatively;
(2) proof that there is a sufficient supply at the earth's surface of
materials susceptible to the influence of ultra-violet light.
There are, of course, numerous other theories of atmospheric
electricity, but none, so far as I know, admits of numerical com-
parison with observation.
VOL. LX.
112 Dr. C. Chree. Observations on Atmospheric
Method of Treating Kew Observations.
§ 16. In discussing the Kew observations 1 have in general em-
ployed a method differing from the grouping system of Exner and
Elster and Geitel, and have also treated the several series separately.
It is clear from data mentioned by Exner that the potential gradients
for individual members of his groups varied in some instances
largely from the mean ; and it was soon obvious that the same
phenomenon would present itself if any similar treatment were
applied to the Kew results. This is undesirable, because by varying
the limits of the groups the accordance of the results with a par-
ticular formula may be much improved, or the reverse. However
impartially, so to speak, the lines may be drawn, there is undeniably
a risk of introducing some fictitious result ; and no critic can feel
that he is in a position to judge of the results until he has examined
for himself the circumstances of the grouping, a labour he naturally
shrinks from. Again a wide range of such an element as vapour
density can be obtained at a particular place only by combining
results from all seasons of the year. This brings us to a second
question. Electrical potential gradient has like vapour density, sun-
shine, and temperature, a large annual variation, only, unlike these
elements, it is highest in winter. It is thus obvious that when obser-
vations from all seasons of the year are treated promiscuously, there
is almost sure to be a marked association of high potential with low
vapour density, little sunshine, and low temperature ; and a judi-
ciously selected formula which makes potential diminish as any one
of these elements increases is certain to show some approach to
agreement with observation. It is thus desirable to compare together
observations from a limited portion of a year, or, even better, from
the same season of a series of years. Similar considerations show
an advantage in treating separately results from different hours of
the day. The isolation of particular seasons and hours has the dis-
advantage of reducing the number of observations compared together.
This is, however, partly compensated for by the greater homogeneity,
of the material. It also enables one in some cases to compare readily
the mean potential gradients which answer at different seasons or
hours to like values of some one meteorological element (see § 23).
Anticipation of some Criticisms.
§ 17. The Kew observations were not limited to quiet, compara-
tively cloudless days, in the same way as the observations of Exner
and Elster and Geitel seem to have been. It may thus not unlikely
be supposed that the Kew results are affected by a variety of dis-
turbing causes, which diminish their intrinsic value and their suit-
Electricity at the Kew Observatory. 113;
ability for comparison with other results free from these extraneous
effects.
As to intrinsic value, there are, at least in England, seasons of the
year when a nearly cloudless day is exceptional. For instance, during
November and December, 1894, in ten days out of eighteen, on which
observations were taken a little before noon, no bright sunshine was
recorded up to the hour of observation. At such a season, if one-
confined one's attention to nearly cloudless days, hardly any data
would be obtained, and they might not unreasonably be regarded as
abnormal.
As to the disturbing action of clouds, this is no doubt in some
cases very large ; but with clouds of this character the influence may
be considerable when they cover only a small fraction of the sky, and
probably, in some cases, even when they are below the horizon. Thus
on one occasion at Kew, when part of the sky was covered by a
thundercloud — so distant that only one or two faint lightning flashes
were detected — sudden changes of potential of thousands of volts
from negative to positive and back again were observed on the roofr
whilst the sun shone at intervals. The sudden alternations of potential
doubtless accompanied flashes of lightning, but no rain was falling
anywhere near, and possibly an observer a few miles away might
have regarded the day as an ideal quiet one. Again, there are other
forms of clouds whose influence seems not unlikely to be much less
than that of invisible vapour in motion nearer the ground. The
mere interception of sunlight by cirrus clouds or detached masses of
cumulus, if we may judge from some few experiments at Kew, has
little if any effect.
It should also be borne in mind that wind velocity and amount of
cloud must both have varied appreciably from day to day, and even
throughout the individual days of Exner's experiments. Some one
— I forget who — defined a "quiet " day as one in which the flame of
Exner's electrometer was not blown out. All the days of the Kew
observations satisfied, of course, this definition, if one is allowed to-
substitute the portable electrometer for Exner's, yet on one occasion
the anemometer was recording a mean velocity of forty miles an
hour.
If aqueous vapour, as Exner supposes, is the sole, or even the-
dominant, agent in producing changes in potential, its activity can-
hardly be confined to days when there is little cloud, and the wind is
low.
§ 18. As regards Elster and Geitel's theory, the data available for
criticism are, I admit, defective, inasmuch as no measurements are
taken at Kew of the dissipative effect of sunlight on negative elec-
tricity. I presume, however, that bright sunshine — such as the
Campbell- Stokes instrument records — always possesses this power,
K 2
114 Dr. C. Chree, Observations on Atmospheric
though doubtless in very variable degrees at different seasons. Solar
radiation occurring after an observation is taken, clearly cannot
affect it. Thus the data got out as to the amount of bright sunshine
recorded prior to the observations must, I think, bear fairly directly
011 Elster and Geitel's theory. If it be true, the potential gradient
must, I think, fall conspicuously as the number of hours of previous
sunshine increases.
§ 19. An objection of a different kind is the proximity of the Kew
Observatory to London. This objection has already been urged
against Greenwich by investigators* whose theories do not harmonise
with the results obtained there. A weekly period exists, they say,
in the Greenwich electrograph curves, and this, they assume, can
arise only from a weekly fluctuation in the amount of smoke, due to
our insular habits of keeping Sunday. If, for a moment, we suppose
the phenomenon and explanation both true — a pretty large assump-
tion— there seems a wide step to the conclusion that results so
affected are useless. I do not myself see that they need lead to
•erroneous conclusions, unless one is dealing with a cycle whose period
is seven days, or a multiple thereof, which a lunation, for instance,
is not.
In the present instance I would point out that the prevailing winds
during each one of the series of observations were from directions
included between N.N.W. and S., and that as Kew Observatory is
some miles to the west of London, while the manufacturing
districts are mainly in the east, it is difficult to see how London smoke
could affect the results. The Observatory, I should add, is situated
in a large open park to the immediate west of the extensive Kew
Gardens.
Even if the prevailing winds had been easterly, I question whether
smoke would have exerted an appreciable influence. The analysis
above mentioned of the electrograph results for 1880, by the late
Mr. Whipple, seems to show that if any relation existed then between
electric potential and wind direction, it varied with the season of the
year; this would hardly have occurred if smoke present in east
winds had an appreciable effect.
Tables of Results.
§ 20. In discussing the observations, I have decided to commence
vby incorporating the actual details in a series of tables. This
will enable any one to judge for himself whether the conclusions
finally arrived at are in accordance with the facts. The first eight
tables give full particulars of the results. The arrangement is not
* See pp. 42—43 of offprint of paper by Ekholm and Arrhenius in ' Bihang till
i. Svenska Vet.- At ad. Handlingar,' Band 19, Afd. 1, No. 8, Stockholm, 1894.
Electricity at the Kew Observatory.
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Dr. C. Chree. Observations on Atmospheric
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Electricity at the Kew Observatory.
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Electricity at the Kew Observatory. 123
chronological, but in descending order of the voltages observed at
station A. In all the tables the humidity of saturation is taken as
100.
§ 21. I have divided the results in each of the previous eight
tables into two groups, according to the order of voltages at station A.
The two groups are equal in number of constituents, except as
regards Table XV, where, following a marked line separating the
voltages, I have included six in the first group, and seven in the
second ; and Table X, where I have included four in the first group,
and three in the second. In tlie last-mentioned case, the best line
of demarcation is doubtful, and, on account of this, and the small
number of constituents, little weight can be attached to the results.
It may seem arbitrary to determine the groups by reference "to
station A exclusively. It is, however, the station least influenced
by buildings, and best fitted for accurate readings, while B is the
worst. Also it will be seen that if one had adopted either C, D, or
E as the standard station, or had taken a mean from all the stations,
whilst the order of the constituents would in some tables have
been considerably affected, the groups themselves would have suf-
fered little or no change.
Table XVII gives the mean potentials at station A for each group
in the several series of observations, with the corresponding mean
values of the meteorological elements.
124
Dr. C. Chree. Observations on Atmospheric
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Electricity at the Kew Observatory.
125
§ 22. A discussion might be based on the previous nine tables alone.
Partly, however, to satisfy those who prefer a grouping system like
that of Exner, I add further tables, in which the observations are
arranged in groups, according to the magnitude of some one meteoro-
logical element. In dealing with vapour density, barometric pressure
and wind velocity, separating lines have been drawn at fixed values
of the element considered. In the case of vapour density the limits
required to be altered with the season. In the case of barometric
pressure and wind velocity it was deemed sufficient to draw only
one separating line, which answered, it will be seen, very nearly to
the mean value. In dealing with sunshine and temperature,* the
division has been into equal, or as nearly equal, groups as possible.
After the tables follows a discussion, which embraces Tables IX to
XVII as well.
Table XVIII.
Arrangement according to Vapour Density.
Forenoon.
Afternoon.
Series
Vapour
Number
Mean
^
Mean
Number
Mean
Mean
of obser-
vations.
grams per
metre.
of obser-
vations.
vapour
density.
potential
at A.
of obser-
vations.
vapour
density.
potential
at A.
,
>6
7
7-71
191
4
6-61
141
I
<6
11
5-27
147
3
5'13
143
r
>7
8
8-12
185
6
8-35
140
II <
7 to 6
8
6-39
170
6
6-45
168
I
<6
8
5-40
333
8
5-46
219
r
>10
4
12-30
104
6
11-11
92
III \
10 to 9
4
9-39
117
5
9-66
122
I
<9
8
8-12
93
3
7-92
96
r
>6
6
7-58
266
4
7-38
286
iv t
<6
7
4-83
279
6
5-37
171
* The n + 1th constituent in the forenoon observation of Series IV is omitted, as
it was doubtful whether to group it with the first n or last n.
126
Dr. C. Chree. Observations on Atmospheric
Table XIX.
Arrangement according to Hours of Sunshine.
Series
of obser-
vations.
Sunshine.
Forenoon.
Afternoon.
Num ber
of obser-
vations.
Mean
sunshine
hours.
Mean
potential
at A.
Number
of obser-
vations.
Mean
sunshine
hours.
Mean
)otential
at A.
<{
Most
Least
8
10
1-94
0
158
169
4
3
1-03
0
154
124
»{
Most
Least
12
12
1-90
0-14
256
203
10
10
6-09
0-99
151
209
m{
Most
Least
8
8
4-62
0'70
93
111
7
7
9-50
3-61
101
106
irf
Most
Least
7
6
1-06
0
237
315
5
5
5-60
1-56
168
266
Table XX.
Arrangement according to Temperature.
Series
of obser-
vations.
Tempera-
ture.
Forenoon.
Afternoon.
Number
of obser-
vations.
Mean
tempera-
ture.
Mean
potential
at A.
Number
of obser-
vations.
Mean
tempera-
ture.
Mean
potential
at A.
i {
Highest
Lowest
9
9
47-2
39-9
170
159
4
3
45-7
37-1
154
124
n {
Highest
Lowest
12
12
51-4
43-5
191
267
10
10
56-1
46-4
145
216
m {
Highest
Lowest
8
8
69-6
63-6
95
109
7
7
74(6
68'0
81
125
XV {
Highest
Lowest
6
6
48-9
36-8
266
297
5
5
49*4
42-7
265
169
Electricity at the Kew Observatory.
Table XXI.
Arrangement according to Barometric Pressure.
127
Forenoon.
Afternoon.
TJ 4- '
of obser-
vation.
pressure,
in inches.
Number
of obser-
Mean
pres-
Mean
potential
Number
of obser-
Mean
pres-
Mean
potential
vations.
sure.
at A.
vations.
sure.
at A.
1 {
>30
<30
12
6
30-20
29-69
178
136
4
3
30-21
29-71
119
172
r
>30
9
30-20
279
6
30-20
184
1
<30
15
29-64
199
14
29 -58
179
m {
>30
<30
8
8
30-23
29 -81
108
96
6
8
30-27
29-75
103
104
TV •[
>30
6
30-35
315
5
30-33
233
<30
7
29-69
238
5
29-64
201
All
>30
35
30-23
212
21
30-25
160
com- •<
bined L
<30
36
29-69
173
30
29-65
162
Table XXII.
Arrangement according to Wind Velocity.
Forenoon.
Afternoon.
Series
of obser-
vations.
Wind
velocity,
miles per
hour.
Number
of obser-
vations.
Mean
velocity.
Mean
poten-
tial.
Number
of obser-
vations.
Mean
velocity.
Mean
poten-
tial.
T r
10 or > 10
13
16-6
174
3
16-7
142
1 1
< 10
5
4-2
140
4
3/2
]41
r
10 or > 10
11
17-7
159
13
17-8
179
1
< 10
13
5-1
289
7
5-9
183
r
10 or > 10
6
15-0
85
11
15-6
101
III |
< 10
10
6-3
112
3
5-3
111
r
10 or > 10
5
16-2
155
1
14-0
197
IV |
< 10
8
4-4
347
9
6-8
219
All
com- 4
bined *•
10 or > 10
< 10
35
36
16-6
5-1
151
232
28
23
16-7
5-7
145
180
VOL. LX.
128 Dr. C. Chree. Observations on Atmospheric
Vapour Density.
§ 23. In Tables XVII and XVIII the forenoon observations of
series IV, and both forenoon and afternoon observations of series II,
support Exner's theory to a certain extent, inasmuch as they decidedly,
on the whole, associate higher potential with lower vapour density.
The forenoon observations, however, of series I lead in both tables
to exactly the opposite result. Also in Table XVII, in five cases
oat of eight, the higher potential is associated with the higher vapour
density. In some instances, e.g., the afternoon observations of
series III and IV, Tables XVII and XVIII lead to diametrically
opposite conclusions. The following are instances of corresponding
means of vapour density and potential, culled from the several tables.
In Table XVIII, 8'12 occurs with both 185 and 93 ; in Table XT,
6-64 with 229 ; in Table XII, 6'62 with 180 ; in Table XVII, 6'57
with 204, 6'35 with 342, and 6'31 with 237 ; in Table XVIII, 6'6l
with 141, 6-45 with 168, and 6'39 with 170. Again, in Tables XV
and XVI we find 6'10 associated with 273, and 6'17 with 217. Lastly,
in Table XVIII we have the following combinations, 5'46 with 219,
5-40 with 333, 5'37 with 171, and 5'27 with 147.
In the face of such results, ifc seems difficult to believe in any
intimate and uniform connexion whatsoever between potential gradient
and vapour density.
Relative Humidity.
§ 24. No special table is devoted to this. In Table XVII no less
than six sub-cases out of eight associate higher relative humidity
with higher potential. It will be noticed, however, that in three out
of the six sub-cases referred to the differences between the mean
humidities answering to the two groups are smaller than in either of
the two sub -cases which associate higher relative humidity with
lower potential. With the exception of the forenoon observations of
series I, and the afternoon observations of series III, the differences
between the mean relative humidities in the two groups are very
small. Thus, on the whole, the evidence in favour of any distinct
association of higher relative humidity and higher potential is insuffi-
cient.
Sunshine.
§ 25. There is in both the Tables XVII and XIX a balance of
evidence in favour of a connexion of low potential with long previous
sunshine. Out of eight sub-cases in each table, five favour this con-
nexion in Table XVII, and six in Table XIX. The only sub- case in
which the tables agree in associating higher potential with longer-
previous sunshine is the afternoon observations of series I, and, for
Electricity at the Kew Observatory.
reasons already mentioned, this is not an important exception. There
is thus a certain amount of general support to Elster and Geitel's-
theory. An examination, however, of numerical details does not
seem favourable to any such intimate connexion between sunshine
and potential, as the formula suggested by them would imply.
Taking, for instance, Table XIX, we notice in series III that, in
the afternoon, a mean potential of 106, answering to a mean of 3*6"
hours' sunshine, falls only to 101 when the hours of sunshine rise to
9'5. Again, in the forenoon observations of the same series, the mean
hours of previous sunshine increase fully six times, while the poten-
tial falls only from 111 to 93.
The afternoon observations of series II are a striking illustration
of the diverse conclusions to which the different methods adopted in
Tables XVII and XIX may lead.
Temperature.
§ 26. The forenoon observations of series IV, and both forenoon
and afternoon observations of series II associate high potential with
low temperature in both Tables XVII and XX ; and the balance of
evidence is unquestionably in this direction. The only sub-case in
which the two tables agree in associating higher potential with higher
temperature is the afternoon observations of series I, which, as
already explained, is the least important of the eight instances.
On the whole, the evidence in favour of a connexion of high poten-
tial with low temperature is just about as strong as that in favour of
a connexion of high potential with little previous sunshine.
Barometric Pressure.
§ 27. Higher potential is associated with higher pressure in the
forenoon observations of each of the four series both in Tables XVII
and XXI. In the afternoon observations, however, the higher-
potential is associated with the lower pressure in three cases out of
four in Table XVII, and in two cases out of four in Table XXI. The
phenomenon, in short, is an apparently clear association of high
potential and high barometric pressure in the forenoon, and an appa-
rent absence of any connexion in the afternoon.
Wind Velocity.
§ 28. A somewhat striking similarity exists here to the phenomena
observed in the case of barometric pressure.
In both the Tables XVII and XXII there is in the forenoon results
a conspicuous association of high potential with low wind velocity.
In Table XXII, it is true, series I observations form an exception,
L 2
130 Dr. C. Chree. Observations on Atmospheric
but it is rather apparent than real. For if, instead often, we adopt
eleven miles an hour as limiting value for the velocity, we get in that
instance two equal groups with the following results : —
Group. Mean velocity. Mean potential.
1st 19-6 153
2nd 6-8 175
Higher potential is here associated with lower velocity, and, as the
groups are equal, the result is presumably a fairer representation of
the facts than that afforded by Table XXII.
Whilst the association of high potential with low wind velocity in
the forenoon seems thus conspicuous, there is in the afternoon no
certain evidence of any such connexion. Thus, in Table XVII,
higher potential is associated as often with higher as with lower
velocity ; and in Table XXII, whilst higher potential is associated
with lower velocity in three sub- cases out of four, the differences
between the mean potentials for the first and second groups are
small. In series III observations the difference is also very uncertain.
If, for instance, we divide these observations into two equal groups,
by taking 15 as separating value for the velocity, we obtain for each
group identically the same mean voltage, 103, though the mean
velocities for the two groups are respectively 18'7 and 8*1.
In Table XXII the figures obtained by combining all four series of
observations, afford an excellent example of what may happen when
results, from all seasons of the year, are treated promiscuously. The
individual series, as we have seen, show no clear association of high
potential with low velocity in the afternoon observations, but, when
the four series are combined, such an association seems conspicuous.
The phenomenon, in reality, is mainly due to the comparatively large
number of instances in which the velocity happened to be high
•during the season when the potential was at its minimum.
General Summary of bearing of Results on Theory.
§ 29. A comparatively small number of observations may be suffi-
cient to disclose defects in an existing physical theory, and yet be
inadequate to warrant the promulgation of a positive opinion as to
the true theory. This is the most satisfactory point of view from
which to regard the facts presented here. They are, in my opinion,
sufficient to show the incompleteness of any theory which assumes
simultaneous values of potential and any single meteorological element
to be so intimately connected that the value of the one can be
deduced, as a rule, from that of the other without taking into
account other important influences. On the other hand, they are
not sufficiently varied to justify the conclusion that the connexions
Electricity at the Kew Observatory. 131
traced in §§ 25 to 28 between low potential and long previous sun-
shine, high temperature, low barometric pressure, and high wind
velocity constitute the normal state of matters at every station,
irrespective of the hour or the season. Provisionally 1 should
prefer to regard these associations as possibly accidental, even at
Kew, but believe they indicate the lines on which more exhaustive
inquiries might profitably proceed.
Another possibility indicated by these associations, viz., that the
potential tends to be higher during anticyclonic than during cyclonic
weather seems also worthy of attention. An attempt was indeed
made in the present instance to check this conclusion directly by
reference to the weather reports of the Meteorological Office. The
published data relate, however, to 8 A.M. and 6 P.M. ; so that, on a
considerable number of occasions the nature of the isobars at the
hours of the observations was uncertain. Taking the remaining
instances, I calculated the mean potential for the cyclonic and anti-
cyclonic conditions separately for each one of the four series, treating
the forenoon and afternoon observations apart, except in the case of
the first series. In live cases out of the seven thus presented, the
mean potential for the anticyclonic group exceeded that for the
cyclonic. There is thus something to be said for the hypothesis. It
should be mentioned, however, that individual occurrences of high
potential in cyclonic weather and of low potential in anticyclonic
weather were not infrequent.
§ 30. The results of the present inquiry are, I believe, irreconcile-
able with Exner's theory, in so far as it connects simultaneous
individual values of potential and vapour density. The question
remains open whether the annual variations of potential and vapour
density may not be related through a formula of Exner's type —
where A and B are constants for a given station, dV/dn and q0
representing monthly means of potential gradient and vapour density
near the ground.
Whilst the data available are far too limited for drawing a final
conclusion, I think it worth while to add in Table XXIII a compari-
son of the results at station A — regarded as 60 inches above the
ground — with those deduced from Elster and Geitel's special form of
the equation
dV/dn =
The figures are the arithmetic means of the values for the forenoon
and the afternoon hours of observation.
Observed.
Calculated.
153
269
205
249
103
176
245
267
132 Observations on Atmospheric Electricity at Kew.
Table XXIII.
Potential at Station A.
Series of
observations.
I.
II.
III.
IV.
The density of aqueous vapour is a quantity having but a small
diurnal variation,* and it would appear, from a table published by
General Sabinef that the calculated mean potential for the day —
taken as the mean of the calculated values for the 24 hours — would
differ but little from that answering to only the two times, 10.30 A.M.
and 4.30 P.M. Thus the calculated values in Table XXIII may be
regarded as close approximations to the true calculated means for the
seasons of the four observations. On the other hand, according to the
table of diurnal variation of potential in the paper by Mr. Whipple
already referred to, the true means obtained from observations at
every hour of the day might be expected to be on an average some
10 per cent, higher than the observed values in Table XXIII. It
ought, further, to be remembered that, as explained in § 4, the
potential at station A must fall short of the true potential at a point
60 inches above the ground in the open, also the fraction of the
existing potential picked up by the portable electrometer may be
appreciably less than unity. Thus the fact that the calculated values
in Table XXIII are so decidedly larger on the average than the
observed is perhaps rather in favour of the formula than otherwise.
If we may judge, however, from the few data in the table, there
seems some ground for the suspicion that the formula will prove to
give too narrow a range.
Before concluding, I have much pleasure in acknowledging the
ready and valuable help I have received from Mr. E. Gr. Constable,
Senior Assistant at the Kew Observatory. Mr. Constable took all
the electrical observations and the measurements of the meteoro-
logical curves, and gave me in addition much useful information
derived from his long experience of the working of the electrograph
and portable electrometer.
* A fact difficult to reconcile with the general form of Exner's theory,
f ' Roy. Soc. Proc.,' vol. 18, 1869, p. 8.
On the unknown Lines in the Spectra of certain Minerals. 133
•• On the unknown Lines observed in the Spectra of certain
Minerals." By J. NORMAN LOCKYER, C.B., F.R.S. Received
May 16,— Read June 4, 1896.
In the first note of the series " On the New Gases ohtained from
Uraninite," by the distillation method, I remarked* " I have already
obtained evidence that the method I have indicated may ultimately
provide us with other new gases, the lines of which are also associated
with those of the chromosphere."
In a subsequent paper " On the Gases obtained from the Mineral
Eliasite," I gave a list of several lines unknown to me, and suggested
that they might indicate the existence of a new gas or gases in that
mineral, and I addedf " Although the evidence in favour of a new
gas is already very strong, no final verdict can be given until the
spectra of all the known gases, including argon, have been photo-
graphed at atmospheric pressure, and the lines tabulated. This part
of the inquiry is well in hand."
The inquiry above referred to has now been completed and in the
following manner : —
Photographs were taken of the spectra at atmospheric pressure of
nitrogen, oxygen, chlorine, carbonic anhydride, coal gas, sulphuric
anhydride, phosphoretted hydrogen, and argon, these being the
gases which, from the experience thus far acquired, are likely to be
associated with those given off by minerals. In addition to these,
the lines of mercury, potassium, and platinum, were also photo-
graphed. The lines of platinum are always present in the spectra
for the reason that the spark is passed between platinum poles, while
the lines of mercury or potassium frequently appear according as the
gases are collected over mercury or potash.
The spectroscope employed has a collimator and camera with
object glasses of 3 in. aperture, and focal lengths of 5 ft. and 19 in.
respectively. Two prisms of 60° were used, giving a length of
spectrum of about 1*75 in. between K and D.
In order to facilitate the reduction of the photographs, the solar
spectrum was photographed under exactly similar instrumental con-
ditions. Micrometric measures were made of H and K, and other
well-known lines throughout the spectrum, and by means of these
and Rowland's wave-lengths, a curve was carefully constructed.
It may be incidentally mentioned that in the photographs of the
spectra of gases at atmospheric pressure, H and K are generally
present as pole lines, being probably due to an impurity of calcium
in the platinum poles.
* ' Eoy. Soc. Proc.,' vol. 58, p. 70.
t ' Roy. Soc. Proc.,' vol. 59, p. 3.
134 Mr. J. Norman Lockyer. On the unknown
In each case in which K was present, the micrometer scale was set
to the reading for this line, and the photograph to be reduced then
adjusted until the K line was under the cross-wires of the micro-
meter. Each line in the spectrum was then in turn brought under
the cross-wires, and the micrometer readings noted. The corre-
sponding wave-lengths were then read off from the curve, and in
this way, lists of the wave-lengths of the lines in the various spectra
were compiled. These lists were then all thrown together into one
table, giving the wave-lengths and intensities of all the lines recorded,
and the spectra in which they appear.
For the wave-lengths thus obtained no greater accuracy than one
indicated by four figures is claimed. It was my intention in the first
instance to give five figures from the more elaborate tables of some
of the elements given by other observers, but this had to be
abandoned in consequence of the considerable variations found in the
tables between the results as given by different observers.
First, as regards the gas from eliasite. The following list gives
the lines obtained in the complete inquiry after the lines due to the
old gases have been eliminated. It should be stated, however, that
several of the lines have wave-lengths very near those of the old
gases ; these have been retained when the more intense lines of the
old gases are absent from the spectra. These cases are pointed out
in the table.
In the case of some of the lines in the visible part of the spectrum,
more accurate wave-lengths have been recorded "by means of a four
prism Steinheil spectroscope. These lines are indicated by (s).
Attempts have been made to concentrate the eliasite gas by the
process of sparking with oxygen over potash, but the quantity of gas
remaining is so small, and so largely admixed with helium and argon,
that a new research, using very much more material, is essential.
It should be remarked that the list of lines which have been
observed and photographed in the spectrum of the gases from
eliasite represents the results of several experiments which have
been made with different samples of the mineral. Some of the lines
have only been seen once, while others have been noted several
times. This suggests that the origins of the lines are very diverse,
and it seems probable that some constituents of the mixture of gases
obtained are absorbed by the potash in the process of sparking.
Next, with regard to the other minerals already examined. As it
is impossible for me to go on with this research for the next few
months, it seems desirable, in the interest of other workers, to give
at the same time a complete list of the unknown lines, so far as the
observations have at present gone, indicating their mineral origins,
and whether or not lines nearly coincident in position have been
observed in any celestial body.
Lines observed in the Spectra of certain Minerals.
"1
I
bfi £ *r --*
a G t~'o
**
co co co co co co co co ^o co co co co
°!
2 S
W) S
'S^
I 3
lol I d
5 S r?
136 Mr. J. Norman Lockyer. On the unknown
i 11
O 0
'
r
O
^
4115 * Orionis
4128 '6 a Cygni, Ei
4131'4aCjgni,Ei
Is
isf
2.Sg
gig
CO CO CO
CO 00 rH Ci
rfi\n) CifH
CO CO XO 1>
O O O O
^ ^* ^* ^*
0 . iH . O ...
O OJ Tp CO O
\O J> ,-| rjt CO
rH <N CO <M O
Lines observed in the Spectra of certain Minerals. 137
888
-P o O
oo 10 N ep
cq IH " w Ii>
00 O5 i~^ C^l
iN (M 00 •'
p cp us . T1 y *° T1 9s
O5 CO CO * GO <N W -#O>
CO<Nrfi COOr-l O(M
U5 if)
x x
X • • X 'X
138 Mr. J. Norman Lockyer. On the unknown
Oi CO CO
oq Tt< oi
i-H (M i-<
rH <M Tft
T— 1 rH rH
CO CO CO
•ajnpou
x • x
'9^T5[SJT3at/BS
XX ' X X X X X
xxxxx
•a^uaSSojg;
x • • x
o cp o o o 9
G^ OS O O O O
»O O & CO CO CO
rH W 'T* ^
COCDCOCOCOCOCOCD
Lines observed in the Spectra of certain Minerals. 139
<M »O O5
CO iH rH
-J (M (M
<o co co
CO CO
s £
cocococococococococococococococccoco
1 40 Dr. J. H. Gladstone. The Relation between the
This information is given in the preceding table (pp. 136 — 139),
in which, for the sake of completeness the lines obtained from eliasite
are also shown.
In most of the experimental work connected with this research, I
have been assisted by Mr. Shackleton, while Mr. Fowler is generally
responsible for the determination of wave-lengths in the less
refrangible part of the spectrum, and Mr. Baxandall for the reduc-
tion of the photographs.
" The Relation between the Refraction of the Elements and
their Chemical Equivalents." By J. H. GLADSTONE, D.Sc.,
F.R.S. Received June 3, 1896.
This paper is intended to give a preliminary account of some
recent investigations into the specific refraction of the elements.
It may be conveniently divided into two distinct parts. The first
part is a revision and extension of the list of specific and atomic
refractions, which was first published in the ' Phil. Trans.' for 1870,
and was reprinted with modifications in a lecture given at the Royal
Institution in 1877. The second part is an amplification of some
deductions made in that lecture.
PART I. — The Specific and Atomic Refractions of the Elements.
The following table contains the atomic weights, the specific refrac-
tions, and the atomic refractions of the elements as revised and
extended. For the atomic weights I have adopted the numbers
recently published by the American Chemical Society's Committee on
Atomic Weights ('J. Amer. Chem. Soc.,' vol. 17), revised up to
January, 1894. In regard to the specific refraction, advantage has
been taken of the work done in some departments of the inquiry
by Landolt, Haagen, Briihl, Topsoe and Christiansen, Mascart,
Becquerel, Kanonnikoff, Soret, Nasini, Grhira, Perrot, Tutton, Lord
Rayleigh, Edwards, and others, as well as many additional observa-
tions made by myself or by Mr. Hibbert.
The atomic refraction is the product of the numbers in the two
earlier columns, that is, it equals P-^-j— , where P is the atomic
weight, and fi—l/d is the specific refraction, that is, the refractivity
divided by the density. Of course, these are not generally deter-
mined by observations of the element itself, but are deduced from
those of its salts or other compounds.
Refraction of the Elements and their Chemical Equivalents. 141
Element.
Atomic
weight.
Specific refraction.
Atomic
refraction.
Hvdrojien
1 '008
1 • AQfl
7*0
O.K-J A
o
9-0
0«7QQ
o
6'R
11 '0
0'43f5 nr A -317
D
Carbon
12 -0
O.qoq
Nitrogen
14 '03
O.qjo P..n
O
16 *0
0* 20*3 nr* fl • 1 f?Q
0, &C.
19 '0
O.AO-I
O'fi 9
19 '94
O'i P;Q
3 .-j/7
Sodium . . . .
23 '05
0.909
Magnesium ....
24 '3
O.OQ'T
DO
6-Q
27 "0
O.OKO
y
9.K
28 '4
O '2^0 m* O '904
7.1 _„ K .O
31 '0
0. KOA
1 R • A, Arc
32 *0
0'42? nr O'"i00 &r>
1 0 .K nT, 1C .A Srf.
35*45
0 "282 or 0 '302
1 0 pfJ nr» 1 (} *7
39 '11
0 '205
8'0
40 '0
O.OKO
in *i
48 '0
0-sa2
OK .n
51 '4
0.401
94.' 7 ?
52 •!
O.on«
-i e .4,
55 '0
0 "208
n'K.
56 '0
0 '209 or 0'355
11 *7 or 19 *9
Nickel
58 '7
0-186
ll'O
Cobalt .... ...
59 »5
0.1 WQ
ifk.q
Copper. .
63 '6
O '184
n'7
Zinc
65 '3
0*151
9'fl
69 '0
0*214
14 "75
75 '0
0*200
15 *0
79*0
0 -339 &c
26 "8 &c
79*95
0-190 or 0'213
15 *2 or 17 -0
Rubidium
85 '5
0*133
11*4
87*66
0-152
13*3
Yttrium.
89 '1
0*197
17 "6
90-6
0-242
21 "9
103 '0
0 *232
23 "9 9
Palladium
Silver
106-5
107 '92
0-213
0-121
22-7
13'1
1]2'0
0*124
13-9
113 '7
0-153
17*4
Tin
119 '0
0*232 or 0*161
27'6 or 19'2
120-0
0*204 or 0*200
24-5 or 24-0
126 '85
0 *192 or 0 *214
24*4 or 27*2
132 '9
0*117
15*6
137 '43
0*117
16*1
138'2
0*143
19*8
Cerium ,
140 '2
0-143
20-0?
Iridium
193 *1
0*165
31 *9 ?
195 -0
0*172
33*5
Gold
197*3
0*127
25*1
200-0
0*107 or 0-099
21*5 or 19*8?
Thallium
204-0
0*106
21*6
Lead
206 -95
0-129 or 0*119
26 *7 ? or 24 *5
208-0
0-154
32*0?
232-6
0*123
28*7
142 Dr. J. H. Gladstone. The Relation between the
The most notable change from previous tables is the increase in
the value of hydrogen and the decrease in that of carbon, but the
necessity of this has been gradually recognised by the principal
workers on the refraction of organic bodies. This in no way affects
the well-determined value CH2 = 7'6.
It should be borne in mind that the specific refraction cannot
claim a constancy equal to that of the atomic weight. The latter is
generally believed to be identical under all circumstances, though
the element may be capable of combining with another in two or more
multiple proportions. On the other hand, several of the elements,
as oxygen and iron, exhibit two or more specific refractions,
which are not in multiple proportion, but depend upon the manner
of combination. The best recognised of these are given in the third
column, and the existence of others is indicated by an " &c." Beside
these well-marked differences, there are many smaller variations,
scarcely, if at all, beyond the limits of experimental error, which
depend upon differences of physical condition or chemical structure.
The numbers given in column 3 are therefore subject to an uncer-
tainty, which may in some instances amount to 5 per cent. Where
there is a greater divergence among the values observed, or where
the deductions have been made from only one specimen, it is indi-
cated by a query.
PART II. — The Relation between the Specific Refraction and the
Combining Proportion of the Metals.
In the paper " On the refraction equivalents of the elements "
previously referred to, it was shown that if the metallic elements be
arranged in the order of their specific refractions, they are roughly
in the inverse order of their combining proportions.
In the lecture at the Royal Institution, I showed that this inverse
order followed an approximate law, namely, that the " specific
refractive energy of a metal is inversely as the square root of its
combining proportion." This generalisation was proved for uni-
valent metals, the figures showing (with the exception of sodium) a
practically constant value for the product of the specific refraction
and the square root of the combining proportion.
By the aid of the table in the first part of this communication, the
generalisation can now be tested throughout the whole range of the
metallic elements.
Refraction of the Elements and their Chemical Equivalents. 143
Univalent Metals.
Metal.
Specific refraction.
^ Combining proportion.
Product.
0-514
2 -65
I.Otf
Sodium • • • •
0-202
4 .on
Potassium . . . . .
0'205
6 .OK
1.90
Rubidium •
0-133
q -94.
1.90
Silver
0-121
10 '3
1 .no
0 *117
11 "5
1 '^
0-107
14*1
1 <f»l
Thallium
0-106
14*3
1 '^1
This confirms the conclusions drawn in 1877, the mean product for
the univalent metals, omitting sodium, being T30. This is in spite
of the fact that lithium and caesium differ from one another in either
factor in the ratio of about 9 to 2. The two metals below the line,
though acting as monads in the compounds from which these values
are deduced, are considered to be dyad and triad respectively. With
them, the product is a little higher ; this will be referred to after-
wards.
Bivalent Metals.
Metal.
Specific refraction.
-s/Combining proportion.
Product.
0-733
2-12
1-55
Magnesium
0-287
0-252
3-49
4-47
1-00
1-12
Zinc . • . .
0-151
5-71
0-87
0-152
6-62
1-00
Cadmium
0-124
7-41
0-92
Barium
0-117
8-29
0-97
Mercury
0-099
10-0
0-99?
Copper . .
0*184
5-64
1-04
Cobalt
0-183
5-45
1-00
Nickel
0-186
5-42
1-01
Manganese
Iron
0-208
0'209
5-24
5-29
1-09
I'll
Lead
0-119
10-17
1-21
Tin
0-232
7-71
1-78
Palladium
0-213
7-30
1-55
With the exception of beryllium, those metals which are properly
bivalent agree closely, although giving values distinctly below that
of the former list. The mean of the values is 0'99. The remaining
five metals, which have well-marked higher valencies, have, as in the
case of the corresponding univalent elements, a somewhat higher
value.
VOL. LX. M
144 Dr. J. H. Gladstone. The Relation between the
Trivalent Metals.
Metal.
Specific refraction.
V Combining proportion.
Product.
Aluminium
0-352
0-214
3-00
4-79
1-05
1-02
Yttrium
0-197
5-45
1-07
Indium
0-153
6-15
0'94
Lanthanum
Cerium
0-143
0-143
6-79
6-83
0-97
0-98?
Gold
0-127
8 '11
1 '03
0-200
5-00
1-00
Antimony
0-204
6 '32
1'29
0-296
3-74
1 -23
0-355
4-32
1-53
The trivalents proper and arsenic agree still more closely amongst
themselves, and give a mean of 1*01, which is practically identical
with that of the bivalents proper.
The other trivalents, which have well-marked higher valencies,
exhibit, as before, a somewhat higher product.
Quadrivalent Metals.
Metal.
Specific refraction.
\/Combining proportion.
Product.
0-242
4-76
1-15
Tin
0-161
5-45
0'88
Lead
0-129
7-19
1-029
0-123
7-62
0*94
0-165
6-95
1-15 ?
0-172
6-98
1-20
In this case the mean is 1*06, nearly the same as with the bivalents
arid trivalents, but the numbers are not so regular.
We have observations on one pentad, namely, antimony. This
gives-
Specific refractive energy 0*200
^Combining proportion 4'9
Product 0-98
These tables show : First, that the metals which have the same
valency, have the same, or nearly the same, constant of refraction
for equivalent weights.
Refraction of the Elements and t/teir Chemical Equivalents. 145
Secondly, that the constants of the bivalent, trivalent, quadrivalent,
and apparently quinquivalent groups are practically the same, rang-
ing about I'Ol.
Thirdly, that when a metal combines in a proportion that indicates
a lower valency than that ordinarily assigned to it, its constant is
tewhat elevated.
I refrain at present from pointing out minor analogies between
closely-allied metals, and from attempting to explain the difference
between the univalent and the other groups ; why sodium should fall
away from the value proper to the alkaline group, and closely
approximate to that of all the other groups; or why beryllium,
bivalent tin, and trivalent iron should be represented by such ex-
ceptionally high figures.
It is to be understood that the values given are all deduced from
compounds in which the metal plays the part of an electro-positive
radicle. Where they combine with oxygen to form the electro-
negative radicle, the values are completely altered, just as we find in
the case of several non-metallic elements.
If we calculate these constants for the square root of the atomic
weight instead of that of the combining proportion, we shall obtain
for the means —
Univalents T30
Bivalents 1'40
Trivalents 1'75
Quadrivalents 2'12
Quinquivalent 2*19
This arrangement does not, as in the former case, give a practically
identical constant for the bivalent, trivalent, quadrivalent, and quin-
quivalent metals. The fact that these numbers increase nearly in
the proportion of the square roots of 2, 3, 4, and 5, indicates that the
relation involved is not between the specific refraction and the atom,
but rather between it and the combining proportion or chemical
[uivalent of the metal. This brings the optical property into
analogy with Faraday's law of electro-chemical equivalents.
I propose to give this product the descriptive name, " Refractive
mstant of equivalent weights." It may be represented by —
SE* = constant,
where S is the specific refraction, and E the chemical equivalent of
le metal.
Some physicists may prefer to make use of the square of the above
formula, namely,
S2E = constant.
146 Mr. J. A. M'Clelland.
If the Lorenz expression for S, namely, ^— - • -=-, be preferred to
* -\-2 a
ifc may be substituted in either of the above formulae.
In either case the actual numbers will, of course, be changed more
or less, but the relation above pointed out will still hold good.
The discrepancies will, however, be somewhat exaggerated by the
change.
This is suggested as a first approximation to a new law. It may be
useful in both chemical and physical science. It holds good, however,
only for the metallic elements.
" Selective Absorption of Rontgen Rays." By J. A. M'CLELLAND,
M.A., Fellow of the Royal University of Ireland. Com-
municated by Professor J. J. THOMSON, F.R.S. Received
June 11,— Read June 18, 1896.
(From the Cavendish Laboratory.)
The experiments described in this paper were made to determine
whether or not the Rontgen rays given off by a vacuum bulb were of
a homogeneous nature, by examining the manner in which they are
absorbed by different substances. The induction coil and vacuum
balb for producing the rays were enclosed in a wooden box thickly
lined with metal, with a small hole in the top, directly beneath which
and close up to it the vacuum bulb was placed. Over the hole a
well-insulated metal disk was placed and connected to one pair of
quadrants of an electrometer. The two pairs of quadrants are first
connected together and with one terminal of a battery of small
storage cells, the other terminal being connected to earth.
The quadrants of the electrometer are then separated from each
other and from the storage cells, and the induction coil turned on.
The Rontgen rays passing through the hole in the box and falling 011
the charged disk discharges it, and the intensity of the radiation is
measured by the rate at which the spot of light from the electro-
meter needle moves across the scale. The metal lining of the box is
connected to earth, and the small hole covered with a single sheet of
tinfoil to screen the electrometer from direct electrical disturbances.
The substance whose absorptive power is to be examined is placed
over the hole so fchat the rays traverse it before falling on the charged
disk.
Evidences of selective absorption were sought for in the following
manner. The rate of leakage was accurately determined when the
rays were passing through one of the substances used, say a plate of
glass. Sheets of tinfoil were then substituted for the glass and the
Selective Absorption of Rontgen Rays.
147
number — w, say — taken such that the leakage from the charged disk
was approximately the same as when the glass was used. The rate
of leak was then measured accurately. The ratio of the rate of leak
with the glass to that with the n sheets of tinfoil gives a measure of
their relative transparency to Rontgen rays.
A number of tinfoil sheets is now placed over the hole ; the glass
plate is placed on the top, and the rate of leak measured. The glass
is removed and the same n sheets of tinfoil as were formerly used
put in its place, and the leakage measured. The ratio of the rate -of
leak in the latter two cases is a measure of the relative transparency
of -the glass and the n tinfoil sheets to the Rontgen rays after they
have been already screened by passing through several layers of
tinfoil.
The two ratios thus obtained should be equal if the Rontgen rays
are all of one kind, but if the glass is relatively less transparent in
the .second case it can only be explained by assuming that the
Rontgen rays are not homogeneous, and that some of them are more
readily absorbed by the glass and others by the tinfoil.
Various substances were tested against tinfoil in the manner
described. With some there was no selective absorption, with others
it was very marked. Glass gave none, with mica and paraffin the
effect was small, with fuchsine, eosine, fluorescine, aesculin, and
barium sulphide the effect was very marked. With several fluores-
cent screens the effect was also marked. Pure water also gave a
distinct though smaller effect.
The table below sets forth the results obtained with these sub-
stances.
Column B gives the quotient of the rate of leak through the sub-
stance in column A to that through a number of tinfoil layers which
gave approximately the same leak. Column C gives the quotient .of
the rate of leak through the substance to that through the same
tinfoil layers after the rays have already passed through four layers
of tinfoil.
Calcium tungstale
Calcium platinocyanide . .
Luminous paint
Potassium platinocyanide
Fuchsine
Eosine
Aesculin
Fluorescine
Barium sulphide
B.
07
80
•o
10
•15
ai
3:3
32
'30
0,
0-85
0-86
0-71
0-87
0-77
1-00
0-90
1-08
0-97
Difference.
0-22
0-44
0-29
0-23
0-38
0-31
0-43
0-21
0-33
M 2
148 Mr. F. Osmond and Prof. W. C. Roberts- Austen.
Of the substances used, the above showed the effect best, but with
wood, paraffin, and water, although small, it could always be
detected. We conclude from the above results that the Rontgen
rays are of different kinds, and that the substances given in the
table differ very much from tinfoil in their selective absorption.
After the rays have been screened by passing through some tinfoil
layers additional layers are much less absorbent, while the absorption
produced by other substances is not so much diminished.
Of the substances tried, those which are fluorescent gave the most
marked difference as compared with tinfoil.
The above results were all obtained with one vacuum tube, which
was working extremely well. It produced a very rapid leak from the
charged disk, and the pressure of its residual air was very small.
In fact, after working for a time it became too strong for the coil
that was being used to work it. Another vacuum tube, in which the
pressure of the residual air was greater and which was not so
efficient in producing leakages, was then used, and several of the sub-
stances used before were again tested, but in no case was any evidence
of selective absorption obtained. As far as the test was efficient, the
radiation from this bulb was homogeneous.
A third tube was then used, more efficient than the last in produc-
ing leakage, but not so good as the first used. With this tube experi-
ments made in the same way as before gave evidence of selective
absorption, but not so marked as with the first tube.
It seems therefore that as a tube becomes more efficient the
character of the rays given off becomes less homogeneous.
" On the Structure of Metals, its Origin and Changes." By
F. OSMOND and W. C. ROBERTS-AUSTEN, F.R.S., Professor of
Metallurgy, Royal College of Science. Received June 10,
-Read June 18, 1896.
(Abstract.)
The authors begin their paper by stating that it has been shown
by Herbert Tomlinson that the atomic volume of metals is intimately
connected wi^h their thermal capacity* and with Young's modulus. f
He considers, in view of the work of Wertheim,J of Maxwell, § and
of Heen,(| and as the result of his own experiments, that the value of
* ' E,oy. Soc. Proc.,' vol. 38 (1884-85), p. 488.
f ' Phil. Trans.,' Part I, 1883, p. 32.
J ' Ann. de Chim. et de Phys.,' vol. 12, 1844.
§ ' Phil. Trans.,' vol. 156, 1866, p. 249.
|| 'Bull, de 1'Acad. Eoy. de Belgique,' vol. 4 (1882).
On the Structure of Metals, its Origin and Changes. 149
the product of the elasticity E, when multiplied by a fractional
power of the atomic volume — , is a constant for all metals,
1)
The divergences shown by ssveral metals from this mean value
arise from the fact that the presence of small amounts of impurity
makes a great difference in their elasticity.
Sutherland* finds a close relation between the atomic volume and
the rigidity of metals, and considers that this rigidity is " in its
essence a kinetic phenomenon, almost as simple in character as the
elasticity of perfect gases."
Professor Fessenden,f moreover, has urged that the cohesion of
metals is proportional to some power of the atomic volume, and he
considers that the rigidity varies as the fifth power of the distance
of the centre of the atoms, or as (atomic volume)^. It will be
evident, therefore, that the atomic volume of a metal is very impor-
tant.
One of the authors purified gold with great care, and alloyed
seventeen separate portions of it with foreign elements in quantities
which were in each case close to 0*2 per cent., and from each sample
of this alloyed gold, bars were cast, 88 mm. long by 7'5 mm. wide by
5'2 mm. thick. The tensile strength, elongation, and reduction of
sectional area (striction) were determined, and the results were
published in the ' Phil. Traits.' in 1888. These results indicated
in a general way, that the tenacity and ductility of gold is increased
by the presence of 0*2 per cent, of an added element of smaller
atomic volume than that of gold itself, while, on the other hand,
these properties are diminished when the atomic volume of the added
element is greater than that of gold.
There are, as might be expected, exceptions and irregularities, but
it is strange that they are not more numerous and more marked.
Even the purest metals are not, from a mechanical point of view,
homogeneous. Under the influence of internal forces which tend to
make them crystalline, and of external stresses which are set up by
contraction during cooling, the invisible molecules become arranged
in visible and more or less highly organised groups. These groups
are separated from each other either by planes of cleavage or by joints
which are often surfaces of least cohesion, and, therefore, of weakness.
This is especially the case when these joints have been accentuated by
the evolution of dissolved gas at the moment of the solidification of
the metal. In alloys, chemical homogeneity may, in turn, disappear,
* ' Phil. Mag.,' vol. 32, 1891, p. 41.
t ' Chern. News/ vol. 6G, 1892, p. 206.
150 Mr. F. Osmond and Prof. W.'C. Roberts-Austen.
and free metals, chemical compounds, or various alloys may fall out
of solution from the liquid mass, and, finally, the eutectic alloy solidi-
fies, but its presence, as a residual fluid facilitates the arrangement of
the parts which have previously solidified.
One of the authors in collaboration with M. Werth* was prob-
ably the first to direct attention to the influence which these fusible
residues, to which the name of " cements " was given, exert on the
working of steel and on the mechanical properties of the finished
products of steel manufacture. Since then M. Andre le Cbatelierf
has repeatedly insisted on this point, correctly enough as a prin-
ciple, though perhaps with a tendency to generalise too much from
ideas which are, in themselves, accurate.
It is possible to distinguish in metals and alloys both the visible
structure and the 'molecular structure, and between them, such
methods of investigation as it is possible to adopt, enable a well
defined line of demarcation to be traced. Attention must, therefore,
be directed to ascertaining to what extent the mechanical properties
of a given sample of metal are due to each of these kinds of struc-
ture, and how far to their mutual relations. This being the case,
the authors considered that it would be interesting to submit
the gold, containing 0'2 per cent, of various elements, to micro-
graphical examination, and, fortunately, the identical specimens
which were submitted to the Royal Society, eight years ago, had been
preserved intact, and were available for examination.
Descriptions are then given in detail of the methods adopted in
preparing, polishing and etching the micro-sections of gold alloyed
with various impurities, photographs of which sections illustrate the
paper. It is difficult to give a brief abstract of the authors' conclusions,
but they may be stated as follows. They consider it to be certain
that there is no relation between either the structure, the appearance
of the fractures, the melting points of the alloyed elements and the
mechanical properties of the masses of alloyed gold. They observe
that every iron metallurgist who examined the photograph of the
micro-section of gold with potassium would form a highly favourable
opinion a.s to the mechanical properties of the mass it represents,
while it is really, from a mechanical point of view, the worst of the
series. On the other hand he would think that the micro-section of
the gold alloyed with zirconium, indicated a structure of deplorable
weakness, while as a matter of fact it might equally well represent
alloys which vary in tenacity from less than half a ton per square
inch to 7f tons, and are either incapable of being extended, or will
elongate 30 per cent.
The authors then proceed to examine the structure of the various sec-
* Osmond and Werth, ' Ann. des Mines,' yol. 8, 1885, p. 5.
t 'Inst. Mech. Engineers Proc,,' April, 1893, p. 191.
On the Structure of Metals, its Origin and Changes. 151
tions in detail, and they conclude the first part of the paper by stating,
that they do not contest in any way, as their previous publications
abundantly prove, the importance of the part which may be played in
the mechanical properties of the alloys by the residues which remain
liquid after the main mass of the alloy has solidified, the alloys being-
tested either at the ordinary temperature or when heated. But, in
order that it may be possible for such cements to intervene and affect
the mechanical properties of alloys, the cements must at least have a
real existence. Nothing indicates that they do exist in ten out of
twelve of the alloys examined. The authors do not express them-
selves too positively on this point, for some new method of etching
may reveal new facts. The impurities which are sought for may
happen to concentrate themselves beyond the particular region which
has been sectioned. These are, however, gratuitous suppositions.
Polishing only indicates the presence of cement in two cases. The
little secondary crystals which are described in the paper might
readily be mistaken for cements, of definite or indefinite composition,
if they were found only in certain specimens, and then in such pro-
portions'as could be accepted. But they occur everywhere, and in all
cases with identical appearances, forms, and dimensions; and, moreover,
are seen tb be collected into crystallites which pervade the whole mass.
These are, therefore, usually and indubitably due to the crystallization
of gold itself, although the alloying substances sometimes (indium and
probably potassium) join up the crystals in question. For the same
reason the dark line of the joints, traced as furrows by the etching,
are very rarely the empty tracks of cement which has been dissolved
away by aqua regia ; their formation, which it is easy to follow in all
its phases, directly connects them with secondary crystallization.
The authors are led to the belief that in the case of ten of their
alloys of the gold with about 0*2 per cent, of various impurities,
solidification of the whole mass has been directly accomplished at a
single time, and that the foreign bodies have remained as solidified
solutions, as they were fltiid solutions when the alloys were liquid,
the impurities being dissociated into their ions in both solid and
liquid. Under these conditions it is difficult to invoke, as explaining
the mechanical properties of the alloy, the intervention of hypotheti-
cal " cements " with relatively low fusing points.
In the second part of the paper attention is directed to the fact
that gold alloyed with bismuth, thallium, antimony, and aluminium
has its structure entirely changed by annealing it in sulphuric acid
at about 250°. The large grains of the metal become divided into a
multitude of little polyhedral grains. Nothing remains of the
original structure, and the effect closely resembles that which is
obtained by annealing steel castings at a bright red heat (800°). It
is pointed out that whatever this observation may signify, the trans-
1 52 Dr. T. E. Thorpe and Mr. J. W. Rodger.
•formation of the structure of a metal, at a temperature so far below
its melting point, and, in the case of the gold-antimony and gold-
aluminium series, far below the melting point of the eutectic alloys,
in the presence of only two-tenths per cent, of a foreign body, is
probably not an isolated fact, and appears to open a new field for
research.
<k On the Relations between the Viscosity (Internal Friction)
of Liquids and their Chemical Nature. Part II." By
T. E. THORPE, LL.D., F.R.S., and J. W. RODGER, Assoc.
R.C.S. Received May 27,— Read June 11, 1896.
(Abstract.)
In tbe Bakerian Lecture for 1894 the authors gave an account of
their work on the viscosity of over seventy liquids, and they discussed
the interdependence of viscosity and chemical composition. In order
to render the investigation more complete, they have now made
measurements of the viscosity of (1) a number of esters or ethereal
salts, and (2) of ethers, simple and compound — groups of liquids, which
with the exception of ethyl ether, have not hitherto been studied by
them. The physicochemical relationships previously established made
such determinations of specialjnterest, for it was shown that one of the
most striking of the various connexions traced between chemical con-
stitution and viscosity was the influence exerted by oxygen according
to the different modes in which it was assumed to be associated with
other atoms in the molecule. The influence which could be ascribed
to hydroxyl- oxygen differs to a most marked extent from that of
carbonyl-oxygen, and it appeared that ether-oxygen, or oxygen
linked to two carbon atoms, had also a value which differed consider-
ably from oxygen in other conditions.
In the present paper the authors give the experimental values for
the viscosity of the ten lowest fatty esters, carefully purified samples
of which had been placed at their disposal by Professor Sydney
Young. With the help of Mr. Barnett, B.Sc., Assoc. R.C.S., they
have also investigated the viscosity of five fatty ethers. By the
kindness of the Photometric Standards Committee they have also
been enabled to make observaiions upon various samples of carefully
prepared isopentane, and they have supplemented their former
observations by a new series of experiments upon ethylbenzene, for a
sample of which they are indebted to Dr. G. L. Moody, of the City
and Guilds Central Institute.
The details of the observations are given in precisely the same
manner as in the first paper, and formulae of the Slotte type showing
Relations between Viscosity and Chemical Nature of Liquids. 153
the relation between viscosity in absolute measure and temperature
are calculated for each liquid. The general results of the observa-
tions are then discussed in the same manner as in the previous
memoir. With regard to the two hydrocarbons, it is found that the
isopentane from fusel oil gives slightly different values from that
originally observed, which was obtained from American petroleum,
and which, although of an approximately constant boiling point, was
undoubtedly a mixture. The new sample of ethylbenzene, however,
gave results which were in very good agreement with those pre-
viously obtained.
The conclusions relating to the graphical representation of the
results may be thus summarised. Both ethers and esters give no
evidence of molecular aggregation, and conform to the rules that : —
(1) In homologous series, the viscosity is greater the greater
the molecular weight.
(2) An iso-compound has a smaller viscosity than a normal
isomer.
(3) The more symmetrical the molecule of an isomeric compound
the lower is the viscosity.
As regards the esters themselves, it is noteworthy, where the com-
parison is possible, that : —
(4) Of isomeric esters, the formate has the larger viscosity.
As regards the algebraical representation of the results, it is shown
that in the expression »/ = C/(l+/3'-f 7^), derived from Slotte's
formula : —
(1) In any homologous series, /3 and 7 increase as the molecular
weight increases.
(2) Of isomeric compounds, the iso-compound has the smallest
coefficient.
(3) Ethyl ether, the symmetrical isomer, has smaller coefficients
than methyl propyl ether.
(4) As regards normal isomeric esters, the formate has the
largest, and the propionate the smallest coefficients, and
the values of the acetate are larger than of the butyrate.
The authors then deal with the relationships existing between the
various viscosity magnitudes — the viscosity coefficient, the molecular
viscosity, and the molecular viscosity work — (1) at the boiling point,
and (2) at temperatures of equal slope, the slope adopted being that
employed in their previous paper, namely, 0'04323, and values for the
oxygen in three different conditions are given for each system of com-
parison in the same manner as in their first communication.
The two main results supported by all the methods of comparison,
both at the boiling point and at temperatures of equal slope, are : —
154 Dr. J. A. Barker.
(1) That the effect which ether-oxygen exerts on the viscosity of
a liquid differs to a marked extent from the effect exerted
either by hydroxyl-oxygen or carbonyl-oxygen, and thai
(2) The viscosity of the formate is abnormally large when com-
pared with that of other esters, and indicates that the
exceptional behaviour of formic acid is to some extent
retained by its ethereal salts.
" On the Determination of Freezing Points." By J. A. HARKER,
D.Sc. Communicated by Professor SCHUSTER, F.R.S. Re-
ceived June 15, — Read June 18, 1896.
(Abstract.)
Of recent years great improvements have been made in the con-
struction of accurate thermometers. For their graduation and study,
the position of the thread for at least two fixed temperatures must
be known with certainty, and one . of these is generally the freezing
point. According to many observers, the methods at present in use
for the determination of this point are unsatisfactory and cannot be
relied on, even when considerable precautions are taken, to more
than about 0*001° to 0'002°. The object of the present communica-
tion is to describe a method by which more consistent results can be
obtained, and which is applicable to all kinds of thermometers.
The method adopted is to cool distilled water in a suitable vessel,
protected from radiation, to a temperature below 0°, to insert the
thermometer, and then bring about the freezing of the water by
dropping in a crystal of ice. The thermometer then rises, and
finally attains a steady temperature, differing only very slightly from
the true zero.
Within the space allotted to this abstract, it is not possible to
describe in detail all the precautions to be adopted and the apparatus
employed, and for these reference must be made to the original
paper. The following brief outline may, however, be given.
The apparatus consists of two portions, the thermostat and the
cooler. The former is a rectangular copper vessel, filled with some
liquid, which can be cooled below 0° without solidifying.
Generally either refined petroleum or a strong solution of common
salt is employed. This vessel communicates by means of two wide
tubes with a system of coils in the cooler, through which the liquid
can be pumped by a rotary stirrer. These coils are surrounded by
a freezing mixture at about —8°, and by this means the circulating
liquid can be cooled and maintained for some time at about —2°.
The distilled water to be frozen is contained in a tube of about
300 c.c. capacity made of clear glass. This is first placed directly
On the Determination of Freezing Points. 155
into the circulating liquid, and cooled quickly to — O5° or — O70.
It is then transferred to a copper cylinder lined with polished metal,
placed in the centre of the thermostat, an annular space of about
1 cm. being left between them. The thermometer whose zero is to be
taken is then quickly fixed in position in a spring clamp, the bulb
and a considerable length of the stem above the zero being immersed
in the water. A crystal of ice is dropped in, and the temperature
quickly rises to the freezing point.
For the details of the arrangement for the illumination of the
divisions, and taking the readings through the mass of the liquid
containing the ice crystals in suspension, reference must be made to
the paper.
The amount of ice formed in the liquid varies of course with the
undercooling. Experiments made with good mercurial thermometers
showed that if ice be present in sufficient quantity, the final tem-
perature attained by the mixture of ice and water is not influenced
perceptibly by variation of the temperature of the circulating liquid
within fairly wide limits. As, however, it is extremely doubtful
whether the indications of any mercurial thermometer can be relied
on beyond O'OOl0, it seemed desirable to control this result by some
other means.
A platinum thermometer and bridge were therefore designed,
capable of indicating with certainty a change of 0*0001°, and a
description of the whole arrangement employed to attain this degree
of accuracy forms the second half of the paper. The resistances in
the bridge were of manganin, whose temperature coefficient is only
about -j1^. that of the usual resistance alloys, and the plugs usually
employed for short circuiting the coils were replaced by copper bars
and mercury contacts of specially low resistance. The thermometers
employed were of about 10 ohms resistance, and were provided with
the compensating leads, devised by Mr. Callendar. The maximum
current which can be used in accurate measurements with these
thermometers is about 0'02 ampere, and therefore the galvanometer
employed required to be extremely sensitive. The instrument
selected was a low resistance astatic one with vertical needle system
of the type described by Weiss, and gives at the greatest sensibility
at which the zero is steady one scale division for 1 x 10~10 ampere
at 2500 scale divisions distance.
With this arrangement the influence of various conditions on the
final temperature attained by the mixture of ice and water was
studied. The results were found to be in close agreement with the
theoretical deductions of Nernst, and it was found that with the
right conditions, it was quite easy to keep the temperature in the
freezing vessel constant, to within one or two ten-thousandths of a
degree for an hour at a time.
VOL. LX. N
156 M. Henri Moissan.
The conclusion drawn from the previous experiments made with
mercurial thermometers as to the small influence of changes in the
external temperature, and in the temperature of the circulating
liquid on that of the freezing vessel, was also confirmed, and it was
found that in the final form of apparatus adopted, a change of two or
three degrees in the temperature of the circulating liquid only
caused the temperature of the mixture in the tube to alter by three
or four ten- thousandths.
"fitude des Carbures Metailiques." By M. HENRI MOISSAN.
Communicated by Professor RAMSAY, F.R.S. Received
June 11,— Read June 18, 1896.
Les combinaisons definies et cristallisees du carbone avec les
metalloides efc les metaux etaient tres peu connues .jusqu'ici. On
savait seulement que certains metaux tels que le fer, pouvaient dis-
soudre du carbone, et donner des fontes.
Les connaissances des chimistes sur ce point etaient peu etendues
parce que ces combinaisons ne se produisent qu'a une temperature
tres elevee. L'application que j'ai faite de 1'arc electrique comme
moyen de chauffage d'un appareil de laboratoire m'a permis d'aborder
cette question. Je resumerai mes recherches sur ce point dans cette
note.
A la haute temperature du four electrique un certain nombre de
metaux, tels que Tor, le bismuth, le plomb, et 1'etain ne dissolvent
pas de carbone.
Le cuivre liquide n'en prend qu'une tres petite quantite, suffisante
deja pour changer ses proprietes et modifier profonderaent sa mallea-
bilite.
L'argent a sa temperature d'ebullition dissout une petite quantite
de carbone qu'il abandoime ensuite par refroidissement sous forme
de graphite. Cette fonte d'argent, obtenue a tres haute temperature,
presente une propriete curieuse, celle d'augmenter de volume en
passant de 1'etat liquide a 1'etat solide. Ce phenomene est analogue
a celui que nous rencontrons dans le fer.
L'argent et le fer purs diminuent de volume en passant de 1'etat
liquide a 1'etat solide. Au contraire, la fonte de fer et la fonte
d'argent dans les memes circon stances augmenteront de volume.
L'alu minium possede des proprietes identiques.
Les metaux du platine a leur temperature d'ebullition dissolvent
le carboue avec facilite et 1'abandonnent sous forme de graphite
avant leur solidification. Ce graphite est foisonnant.
Un grand nombre de metaux vont, au contraire, a la temperature dn
four electrique produire des composes definis et cristallises.
Etude des Carbures Mutalliques.
157
En 1836 Ed. Davy a demontre que le potassium pouvait s'unir au
carbone efc produire un corps decomposable par 1'eau avec degagement
d'un nouveau carbure d'hydrogene. C'est ainsi que ce savant a
decouvert 1'acetylene, dont la synthese devait etre realisee plus tard
par M. Berthelot.
En chauffant un melange de lithine ou de carbonate de lithine et de
charbon dans mon four electriqne, j'ai pu obtenir avec facilite le
carbure de lithium en cristaux transparents degageant par kilogramme
487 litres de gaz acetylene pur.
C2Li2 + H20 = 2LiOH + C2H2.
De meme en chauffant dans mon four electri que un melange d'oxyde
et de charbon, j'ai pu le premier obtenir par une methode generale, a
1'etat pur et cristallise et par notables quantites, les carbures de
calcium, de baryum et de strontium. Le carbure de calcium avait
ete prepare auparavant a Tetat de poudre noire amorphe et impure.
Sans faire 1'historique de la question je rappelerai les recherches de
Wohler, de M. Maqnenne et celles de M. Travers snr ce sujet.
Tous ces carbures se detruisent au contact de 1'eau froide avec
degagement d'acetylene. La reaction est complete, le gaz obtenu est
absolumerit pur. Les trois carbures alcalino-terreux repondent a la
formule C2R, et le carbure de lithium a la formule C?.Li2. La pre-
paration iiidustrielle de 1'acetylene est fondee sur cette reaction.
Un autre type de carbure cristallise en lamelles hexagonales, trans-
parentes, d'un centimetre de diametre, nous est fourni par 1'aluminium.
Ce metal fortement chauffe au four electrique en presence de charbon
se remplit de lamelles jaunes de carbure, que 1'on pent isoler par un
traitement assez delicat, au moyen d'une solution d'acide chlorhy-
drique etendu, refroidie a la temperature de la glace fondante.
Ce carbure metallique est decompose par 1'eau, a la temperature
ordinaire, en fournissant de 1'alumine et du gaz methane pur. II
repond a la formule C3Al4,
C3A14 + 12H30 = 3CH4 + 2[A12(OH)6].
Mon preparateur, M. Lebeau a obtenu dans les memes conditions
•le carbure de glucinium, qui lui aussi, fournit a froid avec 1'eau un
degagement de methane pur.
Les metaux de la cerite vont nous donner des carbures cristallises
dont la formule sera semblable a celle des carbures alcalino-terreux
C2R.
Nous avons etudie specialement, la decomposition par 1'eau des
carbures de cerium C2Ce, de lanthane C2La, d'yttrium C2Y, et de
thorium C2Th.
Tous ces corps decomposent 1'eau et fournissent un melange gazeux,
N 2
158 M. Henri Moissaii,
riche en acetylene et contenant du methane. Avec le carbure de
thorium, 1'acetylene diminue et le methane augmente.
Toutes les experiences entreprises sur le fer ne nous ont jamais
donne de composes definis et cristallises. A la pression ordinaire et a
haute temperature le fer n'a jamais fourni une combinaison definie.
On sait depuis longtemps, grace aux recherches de MM. Troost efc
Hautefeuille, que le manganese produit un carbure CMn3. Ce carbure
peut etre prepare avec le plus grande facilite au four electrique, et au
contact de 1'eau froide, il se decompose, en donnant un melange a
volumes egaux de methane efc d'hydrogene,
CMn2 + 6H20 = 3Mn(OH),+ CH4 + H2.
Le carbure d'uranium, C3Ur2, que j'ai obtenu par les memes pro-
cedes, m'a presente une reaction plus complexe ; le carbure tres bien
cristallise et transparent lorsqu'il est en lamelles tres minces, se
detruit ati contact de 1'eau et fournit un melange gazeux qai contient
une grande quantite de methane, de 1'hydrogene et de 1'ethylene.
Mais le fait le plus interessant presente par ce carbure est le suivant.
L'action de 1'eau froide ne produit pas seulement des carbures gazeux.
II se forme en abon dance des carbures liquides et solides. Les deux-
tiers du carbone de ce compose se retrouvent sous cette forme.
Les carbures de cerium et de lanthane par leur decomposition par
1'eau nous ont fourni de meme, bien qu'en quantite moindre, des
carbures liquides efc solides.
L'ensemble de ces carbures decomposable par 1'eau a la tempera-
ture ordinaire, avec production d'hydrogenes carbones, constitue une
premiere classe de composes de la famille des carbures metalliques.
La deuxieme classe sera fournie par des carbures ne decomposant
pas 1'eau a la temperature ordinaire tels que les carbures de molybdene,
CMo2 ; de tungstene, CW2 ; de chrome, CCr4 et C2Cr3.
Ces derniers composes sont cristallises non transparents, a reflets
metalliques. Us possedent. une grande durete et ne fondent qu'a
une temperature tres elevee. Nous avons pu les preparer tous au four
electrique et nous avons donne le detail de ces experiences ainsi que
toutes les analyses aux ' Comptes rendus de 1'Academie des Sciences
de Paris.'
Les metalloides vont nous fournir aussi avec le carbone, a la tem-
perature du four electrique, des composes cristallises et definis. Nous
citerons par exemple le carbure de silicium, CSi, decouvert par
M. Acheson, et prepare aujourd'hui dans Tindustrie sous le nom de
carborundum ; le carbure de titane, CTi ; dont la durete est assez
grande pour permettre de tailler le diamant tendre ; le carbure de
zirconium, CZr; le carbure de vanadium, CVa. Nous avons indique
la preparation et les proprietes de ces nouveaux carbures.
Un fait general se degage des nombreuses recherches que j'ai
Etude dex Carbures Metalliques. 159
entreprises an four electrique. Les composes qui se produisent a
haute temperature sont toujours de formule tres simple et le plus
sou vent il n'existe qu'une seule combinaison.
Mais la reaction qui nous a paru la plus curieuse dans ces recherches
est la production facile de carbures d'hydrogene gazeux, liquides ou
solides, par 1'action de 1'eau froide sur certains de ces carbures
metalliques. II nous a semble que ces etudes pouvaient avoir
quelque interet pour les geologues.
Les degagements de methane plus ou moins pur qui se rencontrent
dans certains terrains, et qui durent depuis des siecles pourraient
avoir pour origine 1'action de 1'eau sur le carbure d'alumiiiium.
En partant de quatre kilogrammes de carbure d'uranium, nous
avons obtenu dans une seule experience plus de 100 gr. de carbures
liquides.
Le melange ainsi obtenu est forme en grande partie de carbures
ethyleniques non satures, et en petite quantite de carbures acety-
leniques. Ces carbures prennent naissance en presence d'une forte
proportion de methane et d'hydrogene a la pression et a la tempera-
ture ordinaire ; ce qui nous amene a penser que lorsque la decom-
position se fera a temperature elevee, il se produira des carbures
satures analogues aux petroles.
M. Berthelot a etabli en effet que la fixation directe de Fhydrogene
sur un carbure non sature pouvait etre produite par Faction seule de
la chaleur.
L'existenee de ces nouveaux carbures metalliques destructibles par
1'eau peuvent done modifier les idees theoriques qui ont ete donnees
jusqu'ici pour expliquer la formation de quelques petroles, ou autres
produits earbones. Il est bien certain que nous devons nous mettre
en garde centre des generalisations trop natives.
Vraisemblablemeiit il existe des petroles d'origines differentes. A
Autun, par exemple, les schistes bitumineux paraissent bien avoir
ete produits par la decomposition de matieres organiques.
Au contraire, dans la Limagne, 1'asphalte impregne toutes les
fissures du calcaire d'eau douce aquitanien, qui est bien pauvre en
fossiles. Cette asphalte est en relation directe avec les filons de
.peperite (tufs basaltiques), par consequent en relation evidente avec
les eruptions volcaniques de la Limagne.
Un sondage recent fait a Riom a 1200 metres de profondeur a
amene 1'ecoulement de quelques litres de petrole. La formation de
ce carbure liquide pourrait dans ce terrain etre attribue a Faction de
Feau sur les carbures mefcalliques.
Nous avons demontre a propos du. carbure de calcium dans quelles
conditions ce compose peut se bruler et donner de Facide car-
bonique. II est vraisemblable que, dans les premieres periodes geolo-
giques de la terre, la presque totalite du carbone se trouvait sous
160 Messrs. C. T. Heycock and F. H. Neville.
forme de carbures metalliques. Lorsque 1'eau est intervenue dans
les reactions les carbures metalliques onfc donne des carbures d'hydro-
gene et par oxydation de 1'acide carbonique.
On pourrait pent etre trouver un exemple de cette reaction dans
les environs de St. Nectaire. Les granits qui forment en cet endroit
la bordure du bassiii tertiaire laissent echapper d'une facon continue
et en grande quantite du gaz acide carbonique.
Nous estimons aussi que certains phenomenes volcaniques pour-
raient etre attribues a Faction de Feau sur des carbures metalliques
facilement decomposables. Tous les geologues savent que la derniere
manifestation d'un centre volcanique consiste dans des emanations
carburees tres variees, allant de 1'asphalte et du petrole au terme
ultime de toute oxydation, a 1'acide carbonique.
Un mouvement du sol mettant en presence 1'eau et les carbures
metalliques peut produire un degagement violent de masses gazeuses.
En meme temps que la temperature s'eleve, les phenomenes de poly-
merisation des carbures interviennent pour fournir toute une serie de
produits complexes.
Les composes hydrogenes du carbone peuvent done se former tout
d'abord. Les phenomenes d'oxydation apparaissent ensuite et vien-
nent compliquer les reactions. En certains endroits, une fissure
volcanique peut agir comme une puissante cheminee d'appel. On sait
que la nature des gaz recueillis dans les fumerolles varie suivant que
1'appareil volcanique est immerge dans 1'ocean ou baigne par Fair
atmospherique. A Santorin, par exemple, M. Fouque a recueilli de
Fhydrogene libre dans les bouches volcaniques immergees, tandis qu'il
n'a rencontre que de la vapeur d'eau dans les fissures aeriennes.
L'existence de ces carbures metalliques si facile a preparer aux
hautes temperatures, et qui vraisemblablement doivent se rencontrer
dans les masses profondes du globe,* permettrait done d'expliquer
dans quelques cas la formation des carbures d'hydrogene liquides ou
solides et la cause de certaines eruptions volcaniques.
" Complete Freezing-point Curves of Binary Alloys containing
Silver or Copper, together with another Metal." By C. T.
HEYCOCK, M.A., F.R.S., and F. H. NEVILLE, M.A. Received
June 6,— Read June 18, 1896.
(Abstract.)
The paper, of which the following is an abstract, contains the
results of some experiments on the freezing points of alloys of two
* La difference entre la densite moyenne de la terre et celle de la couclie super-
ficielle semble indiquer 1'existence d'une masse centrale riche en metal. La connais-
sance des meteorites holosideres vient a 1'appui de cette hypothese.
Freezing- Point Carves of Binary Alloys. 161
metals, one of the two being in each case either silver or copper. It
is an extension into temperatures as high as 1100° C., of experiments
similar to those at lower temperatures with which we have been
occupied for the last seven years. The results of our previous
experiments, in which mercury thermometers were used, are pub-
lished in the ' Journal of the Chemical Society.' In the work
described in this paper the determinations of temperature were made
by means of platinum, electrical resistance pyrometers of the
Callendar- Griffiths type.
The paper is divided into four sections.
Section I contains a short survey of certain points in the theory
of concentrated solutions which bear on the interpretation of the
experiments.
Section II is devoted to an account of the experimental method.
Section III contains the results of the experiments in a tabular
form, each table being followed by notes and remarks taken from the
experimental note books.
Section IV contains the results expressed graphically as complete
freezing-point curves, together with a discussion and a statement of
the conclusions that can be arrived at from a studv of each curve.
Section I.
If we plot the percentage composition of an alloy horizontally, and
the freezing point vertically we get the freezing-point curve. This,
for a pair of metals, would consist of two branches, each starting
from the freezing point of a pure metal, and descending until they
meet in the eutectic point. Our silver-copper curve gives a fair idea
of this case.
If the metals A and B form a stable compound C, then the theory
as developed by Bakhuis, Booseboom, and by Le Chatelier makes it
probable that the curve will be divided into the systems A C and
C B with two eutectic points, and an intermediate summit at C. This
case is well illustrated by a complete freezing-point curve of copper-
antimony by Professor Le Chatelier, in which two such summits
occur.
Another not infrequent case is probably that of a compound, which
when molten can only exist in a partially dissociated condition. Our
silver-antimony curve resembles such a curve. Other points of
Section I will be best deferred to the summary of Section IY.
Section II.
The alloys, weighing from 200 to 500 grams, were melted in plum-
bago (salamander) crucibles, placed in one of Fletcher's blast furnaces.
162 Messrs. C. T. Heycock and F. H. Neville.
A current of coal gas or of hydrogen was passed through, a pipe-stem
into the crucible ; and this gas, burning over the surface of the
molten metal, proved a perfect protection against oxidation. The
metal was stirred by a plunging stirrer of graphite. The alloys were
made by adding weighed quantities of the second metal in succession
to what was originally a weighed quantity of the first metal, and
taking the freezing point after each addition.
Section III.
This section contains tables divided into parts and into series. The
tables give the freezing point and the composition of each alloy, ex-
pressed in percentage weights of one of the constituent metals, and
also in atomic percentages. By atomic percentage we understand
the number of atomic weights of one metal contained in every 100
atomic weights of the two metals in the alloy.
Section IV.
The complete freezing-point curves given in the paper are for the
following pairs of metals — Ag-Cu, Ag-Pb, Ag-Sn, Pb-Cu, Sn-Cu,
Ag-Sb. But incomplete curves are also given, showing the freezing
points of dilute solutions of Bi, Au, N"i, Fe, Al, in copper, and of Bi,
Pt, Au, Al, and Tl, in silver.
It has not been our aim to make a special study of very dilute
solutions, but the results we have obtained, when utilised in the equa-
tions given in the paper give as the latent heat of fusion of a gram of
copper the number 50 calories, and as the corresponding latent heat
of silver 27 calories. This latter number is considerably greater than
the 21 calories given by Person, and both numbers can only be
regarded as provisional.
The silver-copper curve shows no indication of chemical combina-
tion, unless it be the unexpected fact that the eutectic alloy occurs
exactly at the composition Ag3Cu2. The comparatively small value
of the two atomic falls makes it improbable that the two metals form
monatomic molecules in this alloy.
In the silver-lead and silver- tin curves, which have a good deal of
likeness to each other, the eutectic alloy contains so little silver that
the curve consists almost wholly of the branch starting from pare
silver. For the first 20 atoms of added metal the lead curve agrees
very well, and the tin curve fairly, with the ideal curve of equa-
tion (2) ; but with more lead or tin the total depression becomes
much less than that of the ideal curve at the same concentration.
We are disposed to see in this, not an evidence of chemical combina-
tion, but rather an aggregation of the lead or tin atoms into larger
Freezing Point Curves of Binary Alloys. 163
molecules, a process which, in the case of the silver-lead, might almost
-amount to the separation of the alloy into conjugate liquids near
50 atomic percentages of lead.
The lead-copper affords an excellent example of a phenomenon
which has been predicted, we believe, by Ostwald, but, so far as we
know, has not hitherto been examined experimentally. It is that of
the solidification of a system consisting of two conjugate liquids, a
saturated solution of lead in copper, and a saturated solution of
•copper in lead. For dilute solutions of lead in copper, as far as
7 atoms of lead, the curve is in harmony with equation (2) ; but as
more lead is added its effect rapidly decreases, and from 17 to 65
atoms of lead the freezing point remains constant at 954° C. With
more lead the freezing point again falls, until it reaches the eutectic
point. An examination of the solid alloys shows that the flat part of
the curve corresponds to alloys which have separated into two layers,
while still liquid.
The copper- tin curve embraces all the remarkable bronzes, gun
metal, bell metal, speculum metal, and it is not surprising to find
that it presents singularities. The rapid increase in the steepness of
i)he curve as tin is added suggests that the tin is combining with the
copper to form complex molecules, perhaps of SnCu3 or SnCu4, which
exist in solution. An abrupt change, not only in the direction of the
curve, but pJso in the character of the freezing point, and the nature
of the precipitate at 15*2 atoms of tin is in accordance with the great
changes in the physical and microscopical character of the alloy noted
by Behrens as occurring here. The remarkably straight line of
freezing points from here up to 20 atoms of tin is best explained on
the assumption that an isomorphous mixture of SnCu4 and another
body are separating. The very flat part of the curve between 20 and
25 atoms of tin, along which each freezing point is an extremely
constant temperature may be due to another case of isomorphism, or
may be due to the separation of conjugate liquids. The existence of
& body SnCu3 is not clearly indicated by our curve, although not in-
consistent with it. Double freezing points occur on the horizontal
lines stretching to the left from 15'2 and 20 atoms of tin.
The silver-antimony curve shows an angle at Ag3Sb, but the
eutectic point, though near Ag3Sb2, is not at this formula.
It is worthy of note that in three cases in our curves an angular
depression, and not a summit, occurs at a formula point.
We have made a few experiments on alloys of gold, nickel, and
iron, in copper. The two latter cause a rise, but gold produces a fall
in the freezing point.
Prom what we have hitherto done, silver bismuth promises to
resemble silver-antimony, copper-bismuth to resemble copper-lead.
The silver-gold curve, as is already known, rises above the freezing
164 Mr. A. Mallock.
point of silver ; and the same is true of silver-platinum. The silver
aluminium curve presents some singularities ; but here, as with other
aluminium alloys, we have been troubled by partial oxidation of
the aluminium, and we therefore hope to revise our experiments
with this metal, before publishing them in full.
" Note of the Radius of Curvature of a Cutting Edge." By
A. MALLOCK. Communicated by LORD KELVIN, F.R.S.
Received June 9, — Read June 18, 1896.
The following note may be of interest, partly as indicating the
extreme thinness to which a cutting edge may be brought by the
ordinary process of grinding, and partly also as showing how readily
bhe wave-length of light may be used, with only the simplest appli-
ances, as a practical unit for the measurement of small distances.
The object in view was to find the thickness, or at any rate a
superior limit to the thickness, of the cutting edge of a razor, and for
this purpose two pieces of thin glass (such as is used for covering
microscope slides) were prepared about J inch long and -^ wide.
These were pressed together by a small steel clip A, and the edge-
of the razor was inserted between them as shown in fig. (1).
FIG. 1.
The razor with the thin glasses in this position was then placed on
the micrometer stage of a microscope and illuminated perpendicularly
with light from a soda flame.
With the microscope, interference bands were of course visible
between the thin glasses; and the number of bands, (N), counting
from the spot where the clip pressed the glasses into optical contact
Note of the Radius of Curvature of a Cutting Edge. 165
np to the edge of the blade, gives the distance BC in terms of the
half wave-length.
The distance, BD, was measured by the micrometer, and the
number obtained by dividing BD by the distance between the con-
secutive bands in the neighbourhood of the edge (since the thin
glasses are hardly at all bent so near their free ends) gives when
added to N the number of half wave-lengths in DE.
After these measures had been made, a piece of flat glass was laid
on the blade of the razor as in fig. (2) and the number of interference
FIG. 2.
bands which appeared between the edge and a line parallel to the
edge, but distant BD from it, was counted; and this observation was
repeated with the flat glass on the opposite side of the blade.
The angle H P I, i.e., the angle between the two positions of the
flat glass, was also measured.
If the grinding of the razor was perfect and there was no rounding
at the edge, no interference bands would be visible between the
blade and the glass, but the two would be in contact up to the
actual edge.
Fig. (3) is a large scale cross-section of the blade in the neigh-
bourhood of the edge.
The thickness of the edge K L is
If we put N = number of bands between the clip A and the razor
edge ;
e = the distance between consecutive bands near the edge ;
1 > = the number of bands between the flat glass and either
side of the blade in a distance DB from the edge ;
BD = a and HPI = 0.
166 Note of the Radius of Curvature of a Cutting Edge.
FIG. 3.
£'
We have
Whence
D'F+GE' = 2 a sin 10, nearly;
FK+LG=
KL =
In the case of the razor on which these measures were made
N = 85 % = 3 nz = 2 aje = 8a = 0*00405 in. sin \\Q — | and since
for soda light \\ — O'OOOOllG in. nearly
KL = 0-0000116 x 88-0-00405 x 0'25
= 0-00102-0-00101, nearly.
Thus K L is not greater than O'OOOOl, and if it is assumed that the
actual edge has the curved cross-section, indicated by the dotted line
in fig. 3, the radius of curvature cannot be greater than 1/200,000 of
an inch.
A well sharpened razor will cut a hair, when merely pressed against
it at about an eighth of an inch, or rather more, from the place
where the hair is held.
Human hair taken from the head has a circular cross-section, and
varies in diameter in different individuals from 0'002 to 0*004 in.
With a hair of 0'0025 in, diameter, fixed at one end and free at the
other, it was found that half a grain acting at an eighth of an inch
from the fixed end, bent it through an angle of about 30°.
On the Determination of Wave-length of Electric Radiation. 167
The razor applied at the same distance from the fixed end would
sometimes cnt through the hair before it had bent it as much as 30° ;
and this shows that a force of half a grain must make the pressure
per unit area at the place of contact sufficient to cause crushing or
disruption of the material even when the edge has entered the hair
to a distance comparable with the radius of the latter.
If we assume that the thickness of the edge is 1/100,000 in. and
that it has entered the hair until the length of the edge engaged is
1/1,000 in., the area in contact will be about 1/100,000,000 of a
square inch and the pressure per square inch rather more than
3 tons, if the total force over the area of contact is half a grain.
It is difficult to get any direct measure of the pressure required to
destroy by crushing or shearing the material of which hair is com-
posed, but horn which is of the same nature requires a much larger
pressure than 3 tons per square inch to crush it.
A rough experiment showed that a cylindrical steel punch with a
flat end, began to sink into a block of horn when the pressure was
between 12 and 16 tons per square inch.
It would seem, therefore, that although the optical method shows
that the thickness at the edge cannot be greater than 1/100,000 inch,
the real thickness judged by the pressure per unit area necessary to
cause the edge to cut in the way it actually does, must be considerably
less than this.
" On the Determination of the Wave-length of Electric Radia-
tion by Diffraction Grating." By JAGADIS CHUNDER BOSE,
M.A. (Cantab.), D.Sc. (Lond.), Professor of Physical
Science, Presidency College, Calcutta. Communicated by
LORD RAYLEIGH, Sec. R.S. Received June 2,— Read June
18, 1896.
While engaged in the determination of the " Indices of Refraction
of various Substances for the Electric Ray " (vide ' Proceedings of the
Royal Society,' vol. 59, p. 160), it seemed to me that the results
obtained would be rendered more definite if the wave-length of the
radiation could at the same time be specified. Assuming the rela-
lation between the dielectric constant K and the index JJL as indicated
by Maxwell, to hold good in all cases, it would follow that the index
could be deduced from the dielectric constant and vice versa. The
values of K found for the same substance by different observers are,
however, found not to agree very well with each other. This may,
to a certain extent, be due to the different rates of alternation of the
field to which the dielectrics were subjected. It has been found in
general that the value of K is higher for slower rates of alternation
1 08 J)r. J. 0. Bose. On the Determination of the
and the deduced value of ^ would therefore be higher for slow oscil-
lations, the longer waves being thus the more refrangible. The
order of refrangibilities would in such a case appear to be some-
what analogous to that in an anomalously dispersive medium like
iodine vapour.
With exceedingly quick ethereal vibrations which give rise to
light, there is an inversion of the above state of things, i.e., the
shorter waves are generally found to be the more refrangible. It
would thus appear that there is a neutral vibration region for each
substance at which this inversion takes place, and where a trans-
parent medium produces no dispersion.
It would be interesting to be able to determine the indices of
refraction corresponding to different wave lengths, chosen as widely
apart as possible, and plot a curve of refrangibilities. A curve
could thus be obtained for rock salt, which is very transparent to
luminous and obscure radiations, and fairly so to electric radiation.
Carbon bisulphide, which is very transparent to all but the ultra-
violet radiation, would also be a good substance for experiment.
For the construction of a curve of refrangibility for electric rays,
having different vibration frequencies, the indices could be deter-
mined by the method of total -reflection referred to above. The
determination of the corresponding wave-lengths, however, offers
great difficulties. Hertz used for this purpose the method of inter-
ference, the positions of nodes and loops of stationary undulation
produced by perpendicular reflection being determined by means of
tuned circular resonators.
Sarasin and De la Rive subsequently repeated these experiments
with different sized vibrators and resonators. They found that
the apparent wave-length depended solely on the size of the
resonators. The wave-length found was approximately equal to
eight times the diameter of the circular resonator. From these
experiments it was supposed that the radiator emitted a continuous
spectrum consisting of waves of different lengths, and that the
different receivers simply resonated to vibrations with which they
happened to be in tune. If this supposition be true the emitted
radiation should, by the action of a prism, or better still, a^diffrac-
tion grating, spread out in the form of a continuous spectrum. If,
on the contrary, the radiation is monochromatic, the spectrum should
be linear. The experiments to be described below may throw some
light on this question.
Professor J. J. Thomson, referring to the above case, is of opinion
that the hypothesis of a continuous spectrum is highly improbable.
It is more likely that, owing to the oscillation being of a dead-beat
character, the resonator is set in vibration by the impact of incident
electric waves. Each resonator vibrating at its particular free period,
Wave-length of Electric Radiation by Diffraction Grating. 169
measures its own wave-length. There is, however, one difficulty in
reconciling the theoretical value with that actually obtained.
According to theory, the wave-length should be equal to twice the
circumference, or 2?r times the diameter of the circular resonator.
The value actually obtained by Messrs. Sarasin and De la Rive is, as
has been said before, eight times the diameter of the circle.
Rubens, using a bolometer and Lecher's modification of the slide
bridge, determined the nodes and loops in a secondary circuit in
which stationary electric waves were produced. A curve obtained
by representing the bolometer deflections as ordinates and the
distances of the bridge from one end as abscissae, shows the harmonic
character of the electric disturbance in the wire. It was found that
the wave-length obtained by this method did not depend on the
period of the primary vibrator; the wave-length measured was
merely that of the free vibration started in the secondary circuit by
the primary disturbance.
Hertz's method is therefore the only one for the measurement of
electric waves in air, and the result obtained by this method is
vitiated by the influence of the periodicity of the resonator. It was
therefore thought desirable to obtain the wave-length of electric
radiation in free space by a method unaffected by any peculiarity of
the receiver.
I have succeeded in determining the wave-length of electric
radiation by the use of curved gratings, and the results obtained
seem to be possessed of considerable degrees of accuracy. Rowland's
method of using the curved grating for obtaining diffraction light
spectra was also found well suited for the production of pure spectra
of electric radiation. The focal curve / in this arrangement is a
circle, having as a diameter the straight line joining the centre of
curvature C with the apex M of the grating.
FIG. 1.
Gr, the grating ; M, its apex ; f, the focal curve.
A source of radiation situated on this curve will give a diffracted
spectrum, situated on the same curve defined by the equation
(a+ 6) (sin i ± sin 6) — n\
170 Dr. J. C. Bose. On the Determination of the
where a + b is the sum of breadths of strip and space in the grating,
i = angle of incidence, 6 = angle of diffraction. The sign of 9 is
taken positive when it lies on the same side of the normal as the
incident radiation.
In the above equation there are two interesting cases : —
(1) When the receiver is placed at C, 0 = 0°
(a + 6) sini = n\.
(2) When the deviation is minimum i •= 0
2 (a + 6) sin i = n\.
Arrangement of the Apparatus.
The grating, which is cylindrical, is placed vertically on a wooden
table, with its centre at C, occupied in the diagram by the spiral
spring coherer S. With the radius, which joins the centre to the
apex of the grating, as a diameter, a circle is engraved on the table —
the focal curve — on which the radiator and the receiver are always
kept. A pin is fixed immediately below the apex, and a graduated
ring sunk in the table with this pin as the centre. The graduated
FIG. 2.
The radiator, R, and the receiver, S, revolve round a pivot vertically below the
apex of the grating, along the focal curve. The angles aro measured by the
graduated circle, D.
circle is used for the measurement of the angles of incidence and
diffraction. Two radial arms revolving round the pin carry the
radiator and the receiver. The ends of the arms near the pin have
Wave-length of Electric Radiation by Diffraction Grating. 17 i
narrow slits, through which the pin projects. The slits allow the
necessary sliding for placing the radiator and the receiver on the
focal curve. It would be better to have the sliding arrangement at
the free ends of the arms, the pin passing through the central ends,
acting as a pivot. The circle is graduated into degrees, but one-
fourth of a degree may be estimated.
Description of the Apparatus.
The Radiator. — Electric oscillation is produced between two
metallic beads and an interposed sphere 0'78 cm. in diameter. The
beads and the interposed sphere were at first thickly coated with
gold, and the surface highly polished. This worked satisfactorily
for a time, but, after long -continued action, the surface of the ball
became roughened, and the discharge ceased to be oscillatory.
After some difficulty in obtaining the requisite high temperature, I
succeeded in casting a solid ball and two beads of platinum. There
is now no difficulty in obtaining an oscillatory discharge, and the ball
does not require so mnch looking after.
As an electric generator, I at first used a small Ruhmkorff's coil,
actuated by a battery. I, however, soon found that the usual
vibrating arrangement is a source of trouble ; the contact points soon
get worn out, and the break becomes irregular. The oscillation pro-
duced by a single break is quite sufficient for a single experiment,
and it is a mere waste to have a series of useless oscillations. But the
most serious objection to the continuous production of secondary
sparks is the deteriorating action on the spark balls. Anyone who
has tried to obtain an oscillatory discharge knows how easily the
discharge becomes irregular, and the most fruitful source of trouble
is often traced to the disintegration of the sparking surface. In my
later apparatus I have discarded the use of the vibrating interrupter.
The coil has also been somewhat modified. A long strip of paraffined
paper is taken, and tinfoil pasted on opposite sides ; this long roll is
wound round the secondary to act as a condenser, and appropriate
connexions made with the interrupting key. This arrangement
Fm. 3.
The Radiator.
VOL. LI.
172
Dr. J. C. Bose. On the Determination of the
secures a great saving of space. Two jointed electrodes carry the
two beads at their ends ; the distance between the beads and the
interposed ball can be thus adjusted. This is a matter of importance, as
the receiver does not properly respond when the spark-length is too
large. Small sparks are found more effective with the receiver used.
After a little experience it is possible to tell whether the discharge is
oscillatory or not. The effective sparks have a smooth sound,
whereas non- oscillatory discharges give rise to a peculiar cracked
sound, and appear jagged in outline.
The wires of the primary coil are in connexion with a small storage
•cell through a tapping key. The coil, a small storage cell, and the
key are enclosed in a tinned iron box. It must be borne in mind
that a magnetic disturbance is produced each time the primary
FIG. 4.
The Radiating Box, one-fifth natural size.
circuit of the induction coil is made or broken ; a sudden variation of
the magnetic field disturbs the receiver. The iron box in which the
coil is enclosed screens the space outside from magnetic disturbance.
On one side of the box there is a narrow slit through which the stud
of the press-key projects. In front of the box is the radiator tube,
which may be square or cylindrical. The radiating apparatus used
in the following experiments has a square tube 1 sq. in. in
section. The apparatus thus constructed is very portable.
The one which I often use is 7 in. in height, 6 in. in length,
and 4 in. in breadth. To obtain a flash of radiation it is merely
necessary to press the key and then release it. The break is made
very sudden by an elastic spring.
The Spiral Spring Receiver. — The receiving circuit consists of a
spiral spring coherer in series with a voltaic cell and a dead-beat
galvanometer of D'Arsonval type. An account of this form of re-
ceiver has already been given (vide " On the Indices of Refraction of
Wave- length of Electric Radiation by Diffraction Grating. 173
various Substances for the Electric Ray," ' Roy. Soc. Proc.,' vol. 59,
p. 163). The receiver is made linear by arranging bits of steel spiral
•springs side by side, the sensitive surface being 3 mm. broad and
2 cm. in length. An electrical current enters along the breadth of
the top spiral and leaves by the lowest spiral, having to traverse the
intermediate spirals along the numerous points of contact. The
resistance of the receiving circuit is thus almost entirely concentrated
FIG. 5.
The Spiral Spring Coherer.
at the sensitive contact surface, there being little useless short cir-
cuiting by the mass of the conducting layer. When electric radia-
tion is absorbed by the sensitive surface, there is a sudden diminution
of the resistance, and the galvanometer in circuit is violently de-
flected. By adjusting the electromotive force of the circuit the
sensitiveness of the receiver may be increased to any extent desir-
able. The receiver at each particular adjustment responds best to a
definite range of vibration lying within about an octave. The same
receiver could, however, be made to respond to a different range by
an appropriate change of the electromotive force acting on the circuit.
Very careful adjustment of the E.M.F. of the circuit is necessary to
make the receiver respond at its best to a particular range of electric
vibration.
The Cylindrical Grating. — The source of radiation — the spark gap
— being a line, the curved diffraction grating is made cylindrical.
The spark gap is always kept vertical ; the grating is made of equi-
distant metallic strips, which are vertical and parallel. A piece of thin
sheet ebonite is bent in the shape of a portion of a cylinder and kept
in that shape by screwing against upper and lower circular guide
pieces of wood. Against the concave side of the ebonite are stuck
strips of rather thick tinfoil at equal intervals. Five different
o 2
174 Dr. J. C. Bose. On the Determination of the
FIG. 6.
The Cylindrical Diffraction G-rating.
gratings were thus made with strips or spaces equal to 3 cm.,
2*5 cm., 2 cm., 1*5 cm., and 1 cm. respectively.
The diameter of the cylindrical grating is 100 cm. It would
perhaps have been better to use a grating with a less curvature,
but it must be remembered that the intensity of radiation is very
feeble, and I was apprehensive of the receiver failing to respond
when placed at too great a distance. I find from the sensibility of
the receiver used that it would be possible to increase the diameter of
the cylinder to about 150 cm., and this size I intend to use in the con-
struction of my next grating. The aperture of the grating is
in the following experiments reduced to the smallest practicable
limit.
Account of the Experiments.
The receiver being placed at a suitable position on the focal curve,
the radiator is moved about on the same curve till the diffracted
image falling on the receiver produces response in the galvanometer.
The procedure adopted is as follows. The receiver is placed, say, at
the centre of the grating (0 = 0°). The electric ray at first falls on
the grating at a large angle of incidence. A series of flashes of
electric radiation are now produced by manipulating the key, and
the angle of incidence gradually decreased till the receiver suddenly
responds. The angle of incidence corresponding to the zero angle
of diffraction is thus determined. The receiver is then placed at a
new position on the focal curve, and the corresponding angle of
incidence determined as before. In this way a series of angles of
incidence, with their corresponding angles of diffraction, are found
for each grating.
Wave-length of Electric Radiation ly Di/r action Grating. 175
It should be remarked here that numerous difficulties were
encountered in carrying out the experiments. The reflections from
the walls of the room, from the table, &c., were at first sources of
considerable trouble. By taking special care, I succeeded in elimi-
nating these disturbances. The radiating balls were placed about
1 cm. inside the square tube. This prevented the lateral waves
acting on the receiver. The receiver was provided with a guard tube,
which stopped all but the diffracted radiation reaching the sensitive
surface. The insulated wires from the ends of the receiver were
protected by thick coatings of tinfoil, and led to the galvanometer,
which was placed at a considerable distance. The cell and the
galvanometer were enclosed in a metallic case with a narrow slit
for the passage of light reflected from the galvanometer.
In spite of all these precautions, I was baffled for more than six
months by some unknown cause of disturbance which I could not
for a long time account for. It was only recently, when nearly
convinced of the futility of further perseverance, that I discovered
the mistake in supposing sheets of tinned iron to be perfectly
opaque to electric radiation. The metal box which contains the
radiating apparatus seems to transmit a small amount of radia-
tion through its walls, and if the receiver happens to be in a very
sensitive condition it responds to the feeble transmitted radia-
tion. I then made a second metallic cover for the radiating box,
which precaution was found effective, provided the receiver was riot
brought very close to the radiator. The receiver is still affected if
placed immediately above the radiator tube, though two metallic
sheets be intervening. For this reason I had to postpone taking the
reading for minimum deviation till I had made a radiation-proof
box. A soft iron box (to prevent escape of magnetic lines of induc-
tion), enclosed in a second enclosure of thick copper, would, I expect,
be found impervious to electric radiation.
With the second protective enclosure, all difficulties were prac-
tically removed. As a test for the absence of all disturbing causes, I
observed whether the receiver remained unaffected when the grating
was " off." There is a further test for the absence of external dis-
turbances. The response, if only due to the diffracted beam, depends
on the position of the radiator on the focal curve. If this angle of
incidence is decreased, there should then be no action on the receiver.
I found the positions of the radiator on the focal curve producing
action on the receiver, to be well denned, and I experienced no further
disturbance due to stray radiations.
The grating is fixed vertically on the table, so that its centre is at
the same height as that of the middle of the receiving and radiating
tubes. A small mirror is fixed at the middle of the central strip.
The observer, placing his eye at the same height as that of the
176
Dr. J. C. Bose, On the Determination of the
radiator, levels the grating till the image of the eye is seen reflected
by the mirror.
I first obtained an approximate value of the wave-length with a
2-cm. grating, and then took careful and systematic readings with the
different gratings. By different gratings is meant the same carved
piece of ebonite, on which strips of different breadths were successively
applied. The grating was found fairly adjusted, and the readings
taken on the right side of the grating agreed well with the corre-
sponding ones on the left side, I did not, therefore, think it necessary
to take double readings, but took the various readings alternately on
the right and on the left side. In one case only I found the grating
on one side giving slightly better reading than the other. When the
incident angle is too oblique, the diffracted image is not sharp, and I
therefore did not extend the reading beyond 40° of incidence. Spectra
of the tirst order only were observed. The response in the receiving
circuit was somewhat feeble when 1 cm. or 1*5 cm. grating was used.
But a 2-cm. grating gave stronger indications. With 2*5 and 3 cm.
gratings the response was very energetic and the definition of the
diffracted spectrum very sharp. For example, when the receiver was
kept fixed, and the angle of incidence gradually varied, there was an
abrupt and strong response produced in the receiving circuit, as soon
as the angle of incidence attained the proper value. A slight varia-
tion of this angle, even of less than a quarter of a degree, produced
displacement of the diffracted image, and there was then no further
action on the receiver. Had my graduated circle permitted it, I
could have got more accurate readings. The radial arms carrying
the receiver and radiator were of too primitive a design to make it
worth while to attempt greater accuracy. I give below the readings
of the angles of incidence and the corresponding angles of diffraction
obtained with the different gratings, and the wave-length deduced
from them.
Grating A. — Breadth of strip = 1 cm.
i.
••
\.
Mean \ for A.
38-0°
18°
1-849
35-0
37'0
20
19
1-831
1-854
1 -843
38-75
17
1-837
Wave-length of Electric Radiation by Diffraction Grating. 177
Grating B.— Breadth of strip = T5 cm.
i.
e.
A.
Mean for B.
38-0°
0°
1-847
26-0
10
1-836
1-844
28-5
8
1-849
Grating C. — Breadth of strip = 2 cm.
i.
e.
A.
Mean for C.
27-5°
0°
1 -846
22-0
5
1-847
1-849
20-0
7
1-855
Grating D. — Breadth of strip = 2'5 cm,
i.
e.
A.
Mean for D.
21-5°
0°
1-832
29-5
33-0
- 7
-10
1-852
1-854
1-845
34-0
-11
1-841
Grating E. — Breadth of strip = 3 cm,
i.
e.
A.
Mean for E.
18-0°
0°
1-854
23-25
25-5
- 5
- 7
1-845
1-851
1-848
31-0
-12
1 -843
It would thus be seen that the different values of wave-length
obtained from the above experiments are concordant, the mean value
being 1*846 cm.
I then carefully removed the electrical vibrator, and measured
approximately the size of the sparking balls. The radiator, it must
be remembered, was placed vertically inside a square tube, each of
whose sides is 2'5 cm. The radiator was about 1 cm. inside from the
free end of the tube.
178 On the Determination of Wave-length of Electric Radiation.
The diameter of the central ball = O78 cm.
„ each side bead = O3 „
Distance between the outer surfaces of the beads = 1'5 cm.
?J „ inner (sparking) surfaces ,, = 0'9 „
The wave-length, 1*84, is almost exactly equal to twice the distance
between the sparking surfaces of the beads. Without further ex-
periments with different sized radiators, it is difficult to say whether
the above simple relation is accidental or not. The following rough
determinations, made with a second radiator, may be of some interest
in connexion with the above. I took off the central sphere from the
radiator used in the last experiment, and substituted a larger ball.
The distance between the inner sparking surfaces is then 1'2 cm.
Breadth of Strip = 3 cm.
k.
e.
\.
Mean.
23-0°
0°
2-34
29-0
-5
2-38
2-36
34-5
-10
2-36
The wave-length found is approximately equal to 2*36 cm., and
twice the distance between the sparking surfaces is 2*40 cm.
Conclusion. — The experiments described above seem to prove that
the diffracted spectrum is not continuous, but linear. The method
of determining the wave-length of electric radiation by diffraction
grating is seen to give results which are concordant. The deter-
minations are not affected by the periodicity of the receiving circuit,
the receiver being simply used as a radioscope. With a better
mounting and a finely graduated circle, it would be possible to obtain
results with a far greater degree of accuracy. I hope to send, in
a future communication, the results obtained with a better form of
apparatus, with which I intend to study the relation of the wave-
length with the size of the radiator, and the influence of the enclosing
tube on the wave-length. I shall at the same time send an account
of transmission gratings.
Effects of strong Magnetic Field upon Discharges in Vacuo* 179
14 The Effects of a strong Magnetic Field upon Electric Dis-
charges in Vacuo." By A. A. C. SwiNTON. Communicated
by LORD KELVIN, F.R.S. Received June 10,— Read June
18, 1896.
As is well known, when the lines of force of a magnetic field cut
the path of the cathode rays in a vacuum tube, the rays are deflected
in one direction or another, according to the polarity of the lines of
force. If, on the other hand, the relative positions of the vacuum
tube and the magnet are such that the lines of force and the cathode
rays are parallel, the rays are not sensibly deflected.
Under certain circumstances, however, I have found that with the
rays and lines of force. parallel, other phenomena occur both in regard
to the appearance of the discharge and in connexion with the internal
resistance of the tube.
The apparatus employed consisted of a Crookes tube of the form
illustrated, supported vertically over one pole of a straight electro-
magnet. The tube, which was excited by means of a 10-inch Ruhm-
korff coil, working much below full power, was about 11 inches in
length. The cathode terminal consisted of an aluminium plate at
one end of the tube, and the anode a similar plate at one side. The
tube was exhausted to a degree that gave considerable green fluor-
escence of the glass, with a very slight trace of blue luminescence of
the residual gas in the neighbourhood of the cathode and anode.
The magnet ^mployed had a soft iron core 12 inches in length and
1|- inches diameter. It was wound with 2376 turns of No. 18 S.W.Gr.
copper wire, which, when supplied with continuous electric current
at 100 volts pressure, allowed from 13 to 14 amperes to pass, and
magnetised the iron core practically to saturation.
When the Ruhmkorff discharge passed through the tube, the
magnet not being excited, the general appearance was as shown in
ftff. 1, the walls of the tube showing everywhere green fluorescence,
which was especially strong all over the rounded end of the tube
opposite the cathode. A very small amount of blue luminescence
could also be faintly seen just below the cathode, and also in the
vicinity of the anode.
With the tube and magnet placed as in fig. 2, as soon as the
magnet was excited, the whole appearance of the discharge in the
tube was found to alter immediately to what is shown in the illus-
tration. Excepting for a very little at the top of the tube near the
cathode, and a very bright spot at the bottom immediately over the
magnet pole, all the green fluorescence of the glass disappeared,
while extending from near the cathode to the bright spot at the
180 Mr. A. A. C. Swinton. The Effects of a strong
bottom of the tube, a very bright cone of blue luminescence with a
still brighter whitish blue core, made its appearance. When under
these conditions the tube was slightly moved sideways, the bright
spot at the apex of the cone, and the cone itself moved, the spot and
apex always maintaining a position exactly over the centre of the
magnet pole. At the same time the minor blue luminescence pro-
ceeding from the anode terminal, due probably to the " make "
current of the Ruhmkorff coil, was bent downwards towards the
magnet as shown, and deflected sideways one way or another accord-
ing to the polarity of the magnet, which polarity, however, did not
affect in any way the vertical cathode stream. The internal resist-
ance of the tube, as measured by an alternative spark gap on the
Buhmkorff coil, was also found to be very greatly diminished while
the magnet was excited. With the magnet not excited, the alterna-
tive spark would leap from 1^ to If inches, while, when the magnet
was excited, the gap had to be reduced to about j- inch before the
sparks would pass. As soon as the current from the magnet was cut
off, the appearance of the tube immediately reverted to what is
shown in fig. 1, and its internal resistance increased to what it had
been before.
Magnetic Field upon Electric Discharges in Va«uo. 181
Experiments were also tried with the tube reversed as shown in
fig. 3. In this case the internal resistance was affected by the
magnet just as it had been previously. The appearance of the tube
was also altered by the diminution almost to vanishing point of the
green fluorescence, the presence of very bright blue luminescence on
the under side of the cathode next the magnet, some less bright blue
fluorescence near the anode, and a considerable amount of faint blue
luminescence throughout the remainder of the tube.
In this case, as in the other, the tube reverted to its normal
appearance as soon as the magnet was demagnetised, and the appear-
ance was the same whether the pole of the magnet next the tube was
north or south.
182
Mr. F. G. Baily. The Hysteresis of
— Fiq.S. —
Further experiments with the tube placed horizontally so that the
magnetic lines cut the cathode rays produced the usual deflection of
the latter, but did not seem to have any appreciable effect on the
internal resistance of the tube.
"The Hysteresis of Iron and SteeJ in a Rotating Magnetic
Field." By FRANCIS G. BAILY, M.A. Communicated by
Professor LODGE, F.R.S. Received April 9, — Read June 4,
1896.
(Abstract.)
That the hysteresis of iron varies with the conditions of magnetic
change has been ascertained in some instances, notably those in which
the attractions between the molecular magnets of the Weber-Max-
well-Ewing theory are diminished by super-imposed vibrations in the
Iron and Steel in a Rotating Magnetic Field. 183
molecules. By deduction from this theory it lias been surmised that
the hysteresis in magnetic metals under the influence of a constant
rotary magnetic field will be less than that in an alternating field in
which the magnetising force passes through a zero value. As
familiar practical examples of the two conditions may be instanced :
the armature core of a continuous current dynamo, and the iron cir-
cuit of an alternating current transformer or choking coil.
It is supposed that residual magnetism is due to the combination
of molecular magnets in stable magnetic arrangements, and that the
energy dissipated in any magnetic change corresponds to the work
done in breaking up these arrangements. This energy is rendered
kinetic by the movement of the magnets to form new combinations,
the magnets either oscillating about the new position or moving to
it aperiodically, according to the amount of damping to which they
are subject. It is further suggested that the damping is of an elec-
trical or electro- magnetic nature rather than of africtional character,
being produced by the effect of rapid oscillations of the magnets on
the surrounding particles or medium. Hence any movement of the
molecular magnets during which the formation of new combinations
is checked or prevented will take place with considerable reduction
in the energy loss due to this cause.
Such a condition is realised when the magnetic substance is sub-
jected to a rotary magnetic field of sufficient strength to force the
molecules to maintain a direction parallel to that of the field. If
hysteresis is due only to the formation of new combinations and not
to mechanical restraint, then under these conditions it will vanish
altogether.
Experiments were carried out to verify this deduction. A finely
laminated cylinder of iron was suspended on its axis between the
oles of an electro-magnet which was capable of rotation about the
axis of suspension of the cylinder, thus producing a magnetic field
rotating in a plane at right angles to this axis. The cylinder, though
otherwise free to rotate, was restrained from continuous rotation by
a spring, and the angle of rotation and consequent restoring force of
the spring was indicated by a beam of light reflected from a mirror
on the cylinder. The speed of the electro- magnet and the exciting
current could each be varied.
On rotating the magnet, the armature was dragged round until the
restoring force of the spring equalled the force due to hysteresis, and
the value of the latter could be obtained from the observed deflexions.
The result showed that the value of the hysteresis under these con-
ditions was very different from that obtained in an alternating field.
At first the value was higher for corresponding inductions, but at an
induction of about 16,000 in soft iron and 15,000 in hard steel the
hysteresis reached a sharply defined maximum and rapidly dimin-
184 Mr. E. Rutherford. A Magnetic Detector of
ished on more complete magnetisation, until at an induction of about
20,000 it became very small with every indication of disappearing
altogether. Soft iron and hard steel gave very similar curves, and
in both the curve of hysteresis-induction cut the curve obtained from
the values in an alternating field at a point just before the maxi-
mum. The result fully bears out the deduction from the theory,
and proves in addition that hysteresis is not sensibly due to anything
of the nature of mechanical restraint of the molecules. The form
of the curve also gives clear indications of the three stages of molecular
movement, the first stage giving a slowly rising curve, the second a
straight rapid rise, and the third a straight and much more rapid
descent.
Further experiments were carried out on the effect of speed of
rotation. In an alternating field the speed of reversal has been shown
to be without sensible effect on the hysteresis, and theory points to
this result as a natural deduction. The above apparatus was well
adapted for testing the matter, since the hysteresis per reversal could
be read at each instant independently of the speed. From an ex-
tremely slow speed up to 70 revolutions per second no definite
change was found in the value of the hysteresis. At the same time
several small modifications were noted, produced by rapid variations
in the speed of rotation or magnetising force. The effect lasted
through many revolutions, but ultimately the same steady condition
was arrived at. At a,nd near the maximum value the hysteresis was
very variable. The effects were much more marked in soft iron
than in hard steel, as would be anticipated from the theory of their
constitution.
The experiments in their verification of an untried deduction form
a strong proof of the validity of the molecular theory of magnetism,
and throw some light on the nature of the molecular complex and of
the interactions which take place therein.
"A Magnetic Detector of Electrical Waves and some of its
Applications." By E. RUTHERFORD, M.A., 1851 Exhibition
Science Scholar, New Zealand University, Trinity College,
Cambridge. Communicated by Professor J. J. THOMSON,
F.R.S. Received June 11,— Read June 18, 1896.
(Abstract.)
The effect of Leyden jar discharges on the magnetisation of steel
needles is investigated, and it is shown that the demagnetisation of
strongly magnetised steel needles offers a simple and convenient
means for detecting and comparing currents of great rapidity of
alternation.
Electrical Waves and some of its Applications. 185
The partial demagnetisation of fine steel wires, over which is
wound a small solenoid, was found to be a very sensitive means of
detecting electrical waves at long distances from the vibrator.
Quite a marked effect was found at a distance of over half a mile from
the vibrator.
Detectors made of very fine steel wire may be used to investigate
waves along wires and free vibrating circuits of short wave-length.
Fine wire detectors are of the same order of sensitiveness as the
bolometer for showing electrical oscillations in a conductor.
This detector also has the property of distinguishing between the
first and second half oscillations of a discharge, and may be used for
determining the damping of electrical vibrations and the resistances
of the discharge circuit.
A method of experimentally determining the period of oscillation
of a Leyden jar circuit by the division of rapidly alternating currents
in a multiple circuit is explained. The capacity and the self-induct-
ance of the circuit for high frequency discharges may also be deduced,
so that all the constants of a discharge circuit may be experimentally
determined. In the course of the paper the following subjects were
investigated.
(1) Magnetisation of Iron by High Frequency Discharges. — The effect
of the Leyden jar discharge on soft iron and steel is fully examined.
Steel needles which had been placed in a solenoid and subjected to a
discharge were examined by dissolving them in acid. It was found
that there was apparently only evidence of two half oscillations in
the discharge, and this effect is due to the demagnetising force
exerted by the needle on itself during the discharge.
The effect of continued discharges on the demagnetisation of mag-
netised steel needles was investigated, and also the effect of varying
the length and diameter of the steel needles.
When a discharge is sent longitudinally through a magnetised steel
wire the magnetic moment of the needle is always decreased, due to
the circular magnetisation of the wire by the current through it.
This " longitudinal " detector, when of thin steel wire, was found to
be a sensitive means of detecting electrical oscillations of small
amplitude.
Both the "longitudinal" and " solenoid al " detectors may be
readily used for comparing the intensities of currents in multiple
circuits when traversed by currents of the same period.
(2) Detection of Electrical Waves at Long Distances from the Vibrator.
— A compound detector needle was composed of fine steel wires and
a small solenoid wound over it. When this detector was placed in
series with the wires of a receiver, the electrical oscillations set up in
the circuit tended to demagnetise the magnetised detector needle.
By this method electrical waves from a Hertzian vibrator were
186 Mr. J. S. Townsend.
detected for long distances. An effect was obtained at over half a
mile from the vibrator.
(3) Waves along Wires. — The uses of fine steel wires for examining
the distribution of currents along wires are explained.
(4) Damping of Oscillations. — A method of determining the damp-
ing of discharge circuits is investigated. The absorption of energy
in spark gaps is deduced, and the apparent resistance of the air break
to the discharge determined.
(5) Resistances of Iron Wires. — Quantitative results are given for
the resistance of iron wires for very rapid alternations. The value
of the permeability of the different specimens is deduced, and it is
shown to vary with the diameter of the wire and the intensity of the
discharge.
(6) Absorption of Energy by Conductors. — The absorption of energy
of iron and non-magnetic cylinders placed in solenoid through which
a discharge passed were determined. Iron cylinders were found to
absorb much more energy than copper ones of the same diameter, and
the permeability of the iron for the discharge is deduced.
(7) Determination of the Period of Oscillation of Leyden Jar Dis-
charges. — A method of accurately determining the period of oscillation
is based on the division of rapid alternations in a multiple circuit, one
arm of which is composed of a standard inductance, and the other of
a variable electrolytic resistance.
The value of n, the number of oscillations per second, when the
currents in the branches of the multiple circuits are equal, is, under
certain conditions, given by —
R
where B = resistance of electrolyte to the discharge,
W = value of the standard inductance.
The value of the self-inductance and capacity of the discharge cir-
cuit for very rapid oscillations may also be experimentally deduced.
" Magnetisation of Liquids." By JOHN S. TOWNSEND, M.A.
Dub. Communicated by Professor J. J. Thomson, F.R.S.
Received June 11,— Read June 18, 1896.
(Abstract.)
The experiments on the coefficient of magnetisation of liquids were
made with a sensitive induction balance. Both circuits were com-
muted about sixteen times a second, so that very small inductances
could be detected by the galvanometer in the secondary circuit. The
principle of the method consisted in balancing the increase of the
Magnetisation of Liquids. 187
mutual induction of the primary on the secondary of a solenoid
arising from the presence of a liquid in the solenoid against known
small inductances. Thus, if the sum of the inductances be reduced
to zero, as shown by the galvanometer in the secondary giving no
deflection, the balance will be disturbed to the extent 47T&M, due to
the insertion of a liquid into the solenoid whose coefficient of mag-
netisation is &, and the galvanometer in the secondary circuit will
give a deflection when the commutator revolves. An adjustable
inductance is then reduced by a known amount, m, till the deflection
disappears ; so that we get
47T&M = in .'. k = m/4 7r\f,
where m and M are quantities easily calculated.
Since the formula does not contain either the rate of the rotation
of the commutator nor the value of the primary current, no particu-
lar precautions are necessary to keep these quantities constant.
In all the determinations the magnetising force was varied from 1
to 9 centigram units, and in no case was there any variation in k. The
densities of the salts in solution were also varied over large ranges,
and showed that the coefficient of magnetisation for ferric salts in
solution depended only on the quantity of iron per c.c. that was
present, giving the formula
107fc = 2660 W— 7*7
for ferric salts, where W is the weight of iron per c.c., the quantity
— 7'7 arising from the diamagnetism of the water of solution.
A similar result was obtained for ferrous salts, the corresponding
formula being
107& = 2060 W— 77,
the temperature being 10° C.
The following table shows the coefficient of magnetisation for the
different salts examined, w being the weight of the salt per c.c. of the
solution : —
10? &.
Fe2Cl6 916w-7-7
Fea(S04)3 .... 745^-7-7
Fe,(NO,)6..... 615 w- 7-7
FeCl2 908w-7'7
FeSO4 749*0-7-7
The effect of temperature was also estimated, the results of the
experiments being shown by means of a curve (fig. 1), the x ordinates
of which denote the temperature, and the y ordinates are proportional
to the coefficient of magnetisation, a length corresponding to 50
being subtracted from each for convenience of representation.
VOL. LX, p
188 Prof. J. B. Farmer and Mr. J. LI. Williams.
The first is drawn from results of experiments performed on ferric
chloride containing 0'086 gram of iron per c.c., the second from
ferrous chloride containing O148 gram of iron per c.c., the third
from ferric sulphate containing 0'105 gram of iron per c.c., and the
fourth from an alcoholic solution of ferric chloride.
The curves all show about the same temperature coefficient at
points corresponding to the same temperature.
" On Fertilisation, and the Segmentation of the Spore, in
Fucus." By J. BRETLAND FARMER, M.A., Professor of
Botany at the Royal College of Science, and J. LI.
WILLIAMS, Marshall Scholar at the Royal College of
Science, London. Communicated by D. H. SCOTT, M.A.,
Ph.D., F.R.S. Received May 21,— Read June 18, 1896.
The object of the present communication is to give an account of
the chief results of an investigation into the processes connected
with the formation and fertilisation of the oospheres and the
germination of the spore in Ascophyllum nodosum, Fucus vesi-
culosus, and Fucus platycarpus. The more obvious details of
development have been especially studied by Thuret, and later by
Oltmanns. But neither of these writers paid any special attention
to the behaviour of the cell-nuclei, nor did they succeed in
observing the actual process of fertilisation. Behrens has com-
municated an account (* Ber. d. Deutschen Bot. Gesel.,' Bd. IV) of
some researches made by himself on the fertilisation of the oospheres,
but we are unable to accept his conclusions for reasons shortly to be
recounted.
The material for these investigations was obtained in London from
Bangor, Plymouth, and Jersey, but it was compared with other
material collected and fixed at the seaside at Bangor, Weymouth,
and Criccieth. Furthermore, all the growing apices and eon-
ceptacles for sectioning were collected by one of us directly at the
three last named places. Some samples were gathered between the
tides, and fixed at once, others were first kept for a time in salt
water ; the best results, however, were obtained from plants collected
in a boat about two or three hours after the tide had reached the
plant, and also from other plants taken a short time before they were
left exposed by the ebb tide.
In order to study the fertilisation and germination stages, male
and female plants were kept in separate dishes, and were covered
over so as to prevent drying up. This method gave far better results
than those more usually advocated. On the appearance of the
On Fertilisation, and the Segmentation of the Spore in Fucus. 189
•extruded sexual products, the female receptacles were placed in sea-
water, and after the complete liberation of the oospheres, a few
male branches with ripe antherozoids were first placed in a capsule
of sea water until it became turbid owing to their number. If on
•examination the antherozoids proved to be active, smalt quantities
were added to the vessels containing the oospheres. The latter were
then fixed at intervals of five minutes during the first hour, and then
at intervals of fifteen minutes, up to six hours after the addition of
the antherozoids. After that, samples were killed at longer intervals
up to three days, and this was continued till we had material fixed at
all stages for the first fortnight. At first we used sea water in
which to keep the embryos growing, but a proper solution of
Tidman's sea salt was found to answer quite as well.
For fixing, we tried the following reagents — chrome alum, picric
-alum, Mann's picro-corrosive, corrosive sublimate, and acetic acid ;
these were all dissolved in sea water, absolute alcohol, Flemming's
and Hermann's solutions, and the vapour of osmic and formic acids.
The Flemming's (strong formula) and Hermann's solutions were
•diluted with equal parts of sea water. The first three fixatives were
unsuccessful, acetic-corrosive yielded fair nuclear figures, but the
material proved very brittle, and the spores were somewhat dis-
torted. A portion of the cytoplasm was disorganised and the polar
radiations were not preserved. Absolute alcohol fixed the oospheres
and newly fertilised spores without distortion, but was useless for all
other stages. Vapour fixing with osmic acid succeeded better than
any of the preceding reagents but was greatly inferior to either
Hermann's or Flemming's solutions in preserving the protoplasmic
structure in an unaltered state.
After the material had been fixed it was dehydrated and passed in
the usual way into paraffin, the temperature of which was not
allowed to exceed 50° C., and it was then cut with the microtome.
The sections were stained with Heidenhain's iron-heematoxylin, with
Flemming's triple stain, and a large number of other dyes. The
results, which were compared carefully, led us to rely chiefly on the
two staining processes mentioned, but at the same time we often
obtained valuable preparations with other staining reagents as well.
In spite of repeated attempts, we have not succeeded in observing
the first nuclear division in the oogonium, but the later ones have
been seen both in Fucus vesiculosus and in F. platy carpus, in which
eight oospheres are formed. Oltmanns asserts that in Ascophyllum,
in which only four oospheres are commonly formed, eight free nuclei
occur at an earlier stage, but that four of these ultimately abort,
and do not become centres of cell formation. Our observations tend
to confirm him in this respect, but we found that in some cases
a fifth oosphere, smaller than the rest, was occasionally differentiated,
P 2
190 Prof. J. B. Farmer and Mr. J. LL Williams.
and that when freed from the oogonium it exerted an attraction on
the antherozoids just like its larger sister oospheres.
When an oogonial nucleus is about to divide, it first becomes
slightly, then very much, elongated so as to resemble an ellipse.
Fine radiations are seen to extend from the two ends into the
surrounding cytoplasm. The latter is at first tolerably uniformly
granular, but as the radiations around the polar areas increase, these
regions become cleared altogether of the granules which then become
massed outside them. The nucleus rapidly becomes more spindle-
shaped, and its chromatic elements are chiefly grouped near each
pole, leaving a clear space about the equator in which the nucleolus.
is situated. In this respect the nuclei of Fucus offer a striking con-
trast to those of Pellia epiphylla already described (* Annals of
Botany,' vol. viii, p. 221) by one of us. In the latter plant the
chromatic portion of the nucleus assumes an equatorial position at
the corresponding stage in division, whilst the polar regions are clear.
The polar radiations continue to increase and the nucleus to-
lengthen, until the entire structure recalls the figure of a dumb-bell,
in which the nucleus answers to the handle, and the radiation areas
to the knobs. If the radii be traced outwardly, they are seen to
terminate either in the frothy protoplasm, on the angles where the
foam walls meet, or on the large granules which surround the cleared
areas and are embedded in the foam. This point is one of
considerable importance, and we shall revert to it further on.
No structures were seen which could certainly be identified as
centrosomes, although bodies suggestive of them were often observed ;
but these proved to be so variable in size and position, as well as in
number, that we feel unable to attach any special significance to
them.
The next stage in the mitosis is that in which the interpolar
spindle arises, with the chromosomes disposed upon its equator.
The spindle is very remarkable inasmuch as it is entirely intranuclear,
somewhat resembling that described by Fairchild for Valonia, or by
Harper for Peziza. The nuclear wall can be distinguished until
quite late in karyokinesis, and it is possible that no complete
mingling of the cytoplasm with the contents of the nucleus takea
place here. The spindle is extremely clear, and in several prepara-
tions, owing to a fortunate contraction during manipulation, the
ends of the nuclear part of the spindle also had broken away from
the cytoplasmic poles, and were visible as clean conical structures
forming the poles of the nuclear spindle. The chromosomes were
too minute to admit of their development being satisfactorily studied,
but in all the oogonial spindles their number was estimated at ten
when seen arrayed on the spindle equator. They were only seen in
profile, and consequently it was difficult to be sure whether there
On Fertilisation, and the Segmentation of the Spore in Fucus. 191
were really ten or twelve, but the absolute number is not of im-
portance as all the nuclei were compared from the same aspect.
Remains, more or less preserving the original form, of the nucleolus
were sometimes visible at this and even in a later stage. No division-
planes are formed in the oogonium until the full complement of nuclei
are produced; after this the positions which they will ultimately
occupy are indicated by the heaping up into lines (or rather plates)
of the cytoplasmic granules above referred to. These seem to be
repelled equally from all the nuclei, thus effecting a symmetrical
division of the entire oogonium.
After the complete delimitation of the oospheres within the
oogonium, we observed, as an occasional circumstance, that one of
the oospheres might contain two, or even three, nuclei, a fact also
noticed by Oltmanns. When the oospheres are extruded, and come
to lie free in the water, they grow in size, and are turbid with granules,
which are very abundant in the cytoplasm. The chromatophores
early become distinguishable from the other constituents of the cell,
and the nucleus occupies a central position. It is itself sur-
rounded by a dense layer of cytoplasm, which later on becomes
very strongly marked. About five minutes after the mixing of the
sexual cells, the antherozoids are found to have slipped into many of
the oospheres. We failed to observe the act of penetration, but found
a number of cases in which the antherozoid could be recognised
within the oosphere, before its final fusion with the nucleus of the
latter. It is a roundish, densely staining body, and, unlike the majo-
rity of animal sperm cells as yet described, it imports into the egg no
system of radiations along with it. Judging from the short period
of time elapsing between its penetration of the surface of the oosphere
and its arrival at the exterior of the female nucleus, it must pass
through the intervening cytoplasm with great rapidity. It then
becomes closely appressed to the nucleus, and is about as large as the
nucleolus of the latter. It rapidly spreads over a part of the female
nucleus as a cap, and it presents a less homogeneous aspect than
before. Both it and the female nucleus assume a granular condition,
which is probably to be interpreted as representing a coiling and
looping of the lining of the respective nuclei. Finally the two nuclei
coalesce, and the original components can no longer be distinguished.
Complete fusion may be effected in less than ten minutes after
addition of the antherozoids to the water. These results are in
striking accordance with those described by Wilson in connexion
with the fertilisation of the eggs of echinoderms in his recent " Atlas
of Fertilisation."
A delicate pellicle is meanwhile formed around the periphery of
the oosphere, which is thus easily distinguished from the unfertilised
oospheres, in which such a membrane is wanting. The texture of the
192 Prof. J. B. Farmer and Mr. J. LI. Williams.
cytoplasm also changes, and tends to assume a more definitely radiat-
ing character, the lines starting from the nucleus as a centre.
We observed, not unfrequently, rather large cells in which two-
nuclei of equal size were lying in close juxtaposition. These cells,
with their nuclei, answer exactly to the description given by Behrens
of the fertilisation stage in plants examined by him. We are unable
however, to accept his interpretation, for, in the first place, the
series of fertilisation stages which we have observed, and have
briefly described above, in no way correspond with the appearances
described by him, and secondly, because these large cells (Behrens
himself emphasises their size) are seen in material to which no
antherozoids have had access. Furthermore, the average size of the
young oospores is not obviously greater than that of the oospheres.
themselves. We regard the bodies in question as representing
abnormal developments of oogonial cells, and not as being in any
way concerned with fertilisation. Moreover, we have occasionally
observed one cell in the divided oogonium, much larger than the rest,
to contain two, or even sometimes three, nuclei, and these nuclei are
then always close together. These facts have led us to reject
Behrens' account of the process.
A very large number of experiments were made, in order to deter-
mine, if possible, the time which elapsed between the addition of
the antherozoids to the oospheres and the first division of the spore.
A short summary of different sets of observations on Ascophyllum is
given in the subjoined tables.
SERIES I, — Observations on Ascophyllum conducted at the Seaside,
(a) The antherozoids were added to the oospheres at 10 o'clock A.M.
Lot 1. Fixed 23 hours after the addition of antherozoids. Nucleus preparing for
division.
„ 2. „ 24 ,, „ „ Nucleus divided, rhi-
zoid rudiment present,
no dividing wall.
,, 3 & 4 „ 32 „ „ „ Nucleus divided, no rhi-
zoid, dividing wall pre-
sent.
„ 5. „ 36 „ „ „ Spore divided into about
six cells.
(6) The antherozoids added between 11 and 12 P.M.
Lot 1. Fixed 24 hours after the addition of antherozoids. Nucleus divided, a few
with rhizoid rudiments
and division wall.
„ 2. „ 25 „ ., „ Same result.
„ 3. „ 25 „ „ „ Not beyond spindle
stage.
„ 4. „ 28 „ „ „ Nucleus divided, no rhi-
zoid or dividing wall.
On fertilisation, and the Segmentation of the Spore in Fucus. 193
SERIES II. — Observations on Ascophyllum carried on in the Laboratory.
Antherozoids added between 5 and 7 P.M.
Lot 1. Fixed 22£ hours after the addition of antherozoids. Nucleus divided, no rhi-
zoid or dividing wall.
„ 2. „ 23 „ „ „ Nucleus preparing for
division.
„ 3. „ 23 „ „ „ Same as 1.
„ 4. „ 24£ „ ,, ,, Nucleus divided, rhizoid
present, no dividing
wall.
The above observations prove that there is no essential difference
between the behaviour of material examined in London and at the
seaside respectively.
After fertilisation, the cells rest for a long interval of time — com-
monly about twenty -four hours, as shown in the foregoing table —
before they begin to segment. The principal changes which occur
during the interval are, first, in the rapid increase in the thickness of
the peripheral cell wall, and, secondly, in the more regular arrange-
ment of structure exhibited by the protoplasm. The alveolar, or
foam character is extremely clear, and the chromatophores, which by
this time have become very prominent, are noticed to be situated in
the angles formed by the convergence of the foam walls ; they are
often bent and otherwise distorted, and so accommodate themselves
to the structural condition of the foam. Other granules, which
stain deeply, and probably represent food reserve of a proteid nature,
are also abundantly scattered through the cytoplasm.
The first segmentation-division resembles, in a general way, the
oogonial nuclear divisions already described, and the polar areas
become similarly cleared of granules. The achromatic threads form-
ing the polar radiations are very clearly seen to be attached to the
foam-like structure of the cytoplasm, and, indeed, in some cases,
insensibly to pass into it. At other times fibrils end on granules (or,
perhaps, on the protoplasmic lining of the granules), and sometimes
again a fibril may fork, and its branches end either on granules or
on the foam angles. The inference to be drawn from these facts
seems to be that the radiations are the result of a change — a differ-
entiation— in the protoplasm as it already exists, and that they do not
owe their origin to the presence of any special " spindle-forming sub-
stance," by virtue of which they may be supposed to develop and
"grow" as new structures in the cell. We propose, however, to
discuss the general bearings of our observations on this and on other
questions of theoretical interest in a future memoir, in which the
evidence for our views will be set forth in detail.
When the achromatic nuclear spindle appears, it also, as in the
194 On Fertilisation, and the Segmentation of the Spore in Fucus.
oogonial mitoses, is intranuclear, and it is often separated from, the
well-defined persistent nuclear wall by a clear space. The chromo-
somes, when assembled on the spindle, at the equator, are seen to be
twice as numerous as in the oogonial nuclei, i.e.., seen in profile we
counted them as twenty in number. We were unable to distinguish
any such grouping of the chromosomes as would lead to the conclu-
sion that the chromosomes of the mate and female nuclei respectively
had so far preserved their original identity as to appear in the form of
two separate groups. The long interval of time which, in Fucus,
elapses between fertilisation and the first nuclear division possibly
may admit of a more thorough mingling or fusion of the parental
chromosomes than would seem to be the case in some animals, e.g.,
the Copepoda as described by Riickert and by Hacker.
During the diaster stage the connecting achromatic fibres are at first
very distinct, but they soon become fainter, and no cell-plate is
formed across them. The two daughter nuclei gradually pass into
the state of rest, each being first hemispherical, with crenate projec-
tions on the flattened side turned towards its sister nucleus. Only
after nuclear division is complete does the first cell wall appear. The
cell is sometimes spherical when this happens, and then it is divided
into two similar hemispheres. Further divisions may then appear,
whilst the general contour of the embryo still remains more or less
spherical. These cases occurred most frequently when the germinat-
ing spores were illuminated on all sides. But most commonly the
first cell wall cuts the spore into two dissimilar halves, one of which
grows out and forms a rhizoid. Often this projection is already
apparent even before the first nuclear division occurs, and in any
case one of the two daughter nuclei always passes down into the
protuberance.
The immediately succeeding divisions have been sufficiently de-
scribed by Thuret and others, but we may remark that the division
of the nuclei in all cases precedes the formation of a cell plate, which
is not formed in connexion with the achromatic connecting fibrils as
in the higher plants.
The doubled number of the chromosomes is retained during the
vegetative divisions of the thallus, and is constant throughout the
somatic cells of the mature Fucus plant. Hence it follows that the
reduction in the number of the chromosomes (in the female plants),
is associated with the differentiation of the oogonium — the mother cell
of the sexual products. Thus Fucus, in this respect, approximates
more closely to the type of animal oogenesis than to that which obtains
in those higher plants in which the details of chromosome reduction
has been followed out.
Regarded from the standpoint of the number of its chromosomes,
the Fucus plant resembles the sporophyte of the higher plants, whilst
Changes in the Dimensions of Carapace of Carcinus moenas. 195
the gametophyte of the latter, with its reduced number of chromo-
somes, finds its analogue merely in the maturing sexual cells of Fucus.
But until we know more of the nuclear changes as they occur in other
Algae, and especially in the more primitive forms, it seems unadvis-
able to go further than to indicate the possibility that we may require
to revise our present ideas on the comparative morphology of the
higher and lower groups of the vegetable kingdom. Even if we regard
the reduction in the number of the chromosomes as a fact which is
primarily of physiological importance, we may safely conclude, from
the universality of its occurrence, that it is also intimately connected
with the phylenogenetic development of living forms, and hence it
must meet with due recognition on the part of the morphologist who
is engaged in comparing the life-history of one group of organisms
with that of others.
" On certain Changes observed in the Dimensions of Parts
of the Carapace of Carcinus mcenas." By HERBERT
THOMPSON. Communicated by Professor W. F. R. WELDON-
F.R.S. Received May 19,— Read June 11, 1896.
In making some measurements of young male Carcinus mamas
from Plymouth, corresponding to those made by Professor Weldon
on young females of the same species, and published by him in the
Report of a Committee for conducting statistical inquiries into the
measurable characteristics of plants and animals (' Roy. Soc. Proc.,'
vol. 57, p. 360), some interesting facts were observed as to changes
taking place in the relative dimensions of certain parts of the
carapace of these crabs in the space of the last three years.
The carapace of the adult male crab, measured in the median
antero-posterior line is, roughly, from 40 to 60 mm. long. Now, of
young male C. mcenas collected at random at Plymouth in the year
1893, I had, for the purposes of measurement, 3,077 specimens,
ranging between 10 and 15 mm. in length of carapace, and on these,
besides the carapace length, as above defined, two other measure-
ments were taken, viz. (1) "frontal breadth," the distance in a
straight line between the tips of the two teeth which form the outer
"boundaries of the orbits, and (2) the "right dentary margin,"
measured in a straight line from the tip of the first to that of the
last lateral tooth on the right side of the carapace.
The measurements were made in the way described in the Report
above mentioned (ibid., pp. 361 — 2) : and owing to the rapid growth
and alteration of proportional dimensions in the young crabs, they
were sorted into groups, the members of each of which differed by
less than 0'2 mm. in carapace length, thus giving five groups for
196 Mr. H. Thompson. On certain Changes observed in the
every 1 mm. of growth in carapace length, or twenty-five groups
for the whole range of 10 — 15 mm. carapace length. The numbers
contained in the separate groups ranged from seventy-two in the
smallest group to 178 in the largest group. The arithmetical
mean and mean error in each group is set out in Table I infra.
Similar measurements were made in the case of 1,957 young male
C. mcsnas from Plymouth of the year 1895. These were likewise
divided into groups differing by 0*2 mm. of carapace length : and
the numbers contained in the twenty-five groups between 10 and
15 mm. carapace length ranged from thirty-four in the smallest one
to 111 in the largest. The arithmetical means and mean errors are
given in Table I infra.
On comparing the two sets of measurements (expressed in terms
of the carapace length which was taken as the unit) it appears, as
regards the " frontal breadth," that in every one of the twenty-five
groups without exception the average size of the frontal breadth in
the 1893 crabs exceeded that of the 1895 crabs of corresponding size.
Seeing how small the groups are the result is a striking one, and is
given in greater detail in the following Table : — -
C. mcenas. — Frontal Breadth.
Carapace length in
millimetres.
Average excess of 1893 crabs over
1895 crabs.
In thousandths of
carapace length.
In millimetres.
10—11
11—12
12—13
13—14
14-15
6-30
7-29
6-73
5-26
3-53
0*07
0'08
0'08
0-07
0-05
On the other hand, if the species in 1895 has a smaller average
frontal breadth, it compensates for the deficiency by having a larger
right dentary margin. This was found to be the case in twenty- three
out of the twenty-five groups, the two non-conformist groups lying
one near each end of the range. The arithmetical means and mean
errors are given in Table I infra, and the results, tabulated in a
corresponding form to those of the frontal breadth measurements,
are as follows : —
Dimensions of Parts of the Carapace o/Carcinus moenas. 197
C. moenas. — Right Dentary Margin.
Carapace length in
millimetres.
Average excess of 1895 crabs over
1893 crabs.
In thousandths of
carapace length.
Tn millimetres.
10-11
11—12
12—13
13—14
14—15
1-39
2'09
1-87
1-56
1-42
O'Ol
0-02
0-02
0-02
0-02
As these results seemed to indicate that a change in regard to
these dimensions was taking place in the species, it was desirable to
compare similar measurements in the adult. Fortunately Professor
Weldon was able to supply me with 254 specimens of male G. mo&nas
with a carapace length ranging between 40 and 63 mm., taken at
Plymouth at random in 1892-3 : and for comparison he procured
496 individuals collected at Plymouth in January of the present year
and corresponding in size.
Measurements similar to those made on the young ones gave the
following results : — In frontal breadth the 1892-3 crabs exceeded
the 1896 crabs on an average by 8'85 thousandths of their carapace
length, which for an average length of 50 mm. is equivalent to
0*44 mm., while in the right dentary margin the 1896 crabs exceeded
those of 1892-3 on an average by 3'1 thousandths, or an equivalent
of 0'16 mm., thus fully confirming the results arrived at in the
young ones.
Whether these results indicate a permanent change in the species
at Plymouth in respect to these particular dimensions of the carapace,
tending to the establishment of a new variety, or whether it is a
mere oscillation such as, for all we know, may be constantly going on
in the relative dimensions of the various parts of the members of al)
species, can only be decided by further measurements, which, it is
hoped, may be continued on the same species after another interval
of two or three years. Meanwhile, the persistence with which the
same tendency asserts itself in the twenty-six groups into which we
have divided these crabs of 1892-3 and 1895-6 is remarkable, and
may perhaps induce others to take measurements of other animals at
definite intervals, and establish similar comparisons.
I wish to add my hearty thanks to Professor Weldon for suggest-
ing the line of investigation and furnishing material and ever-ready
help.
198 Changes in the Dimensions of Carapace of Carciims moenas.
Interruption of Afferent and Efferent Tracts of Cerebellum. 199
"Phenomena resulting from Interruption of Afferent and
Efferent Tracts of the Cerebellum." By J. S. RISIEN
RUSSELL, M.D., M.R.C.P., Research Scholar to the British
Medical Association, Assistant Physician to the Metro-
politan Hospital, and Pathologist to the National Hospital
for the Paralysed and Epileptic, Queen's Square. Com-
municated by Professor VICTOR HORSLEY, F.R.S. Received
June 17,— Read June 18, 1896,
(From the Pathological Laboratory of University College, London.)
(Abstract.)
The research was undertaken in the hope of obtaining evidence in
support of or against the view that the cerebellum exercises a direct
influence on the spinal centres, as opposed to any indirect influence
exerted through the agency of the cerebral cortex. The inferior
peduncle of the cerebellum was accordingly divided on one side, the
organ itself and its other peduncles being otherwise left intact, and
the results obtained by this procedure were controlled by experiments
in which the lateral tracts of the medulla oblongata were divided on
one side without injury to the pyramid on the one hand or to the
posterior columns and their nuclei on the other. Further control
experiments consisted in dividing transversely the posterior columns
and their nuclei a few millimetres above the calamus scriptorins, on
one side, without including the lateral tracts of the medulla in the
lesion.
The results obtained by these different experiments were supple-
mented by others in which the electrical excitability of the two cere-
bral hemispheres was tested and compared, immediately after division
of one inferior peduncle of the cerebellum, and at some later period,
such as three weeks, after the section of the peduncle ; also after
partial hemisection of the medulla in which all the structures on one
side were divided, with the exception of the pyramid which was left
as far as possible intact.
Other experiments consisted in observing the ways in which con-
vulsions, induced by the intravenous injection of the essential oil of
absinthe, were modified by division of one inferior peduncle of the
cerebellum, by partial hemisection of the medulla in which the
pyramid was the only structure left intact on one side, and by
transverse section of the posterior columns and their nuclei, on one
side, a few millimetres above the calamus scrip torius.
Considered in conjunction with results previously obtained by the
author and others after ablation of one lateral half of the cerebellum,
and after intracranial section of the auditory nerve, the results now
200 Dr. Russell. Phenomena resulting from Interruption
obtained afford valuable information with regard to many of the
functions of the cerebellum ; but they are not claimed as supplying
definite information on the important question as to whether the
cerebellum exercises a direct downward influence on the spinal
•centres or not. Many of the results obtained suggest the possibility
of such a downward influence ; but most of the effects can as readily
be explained by supposing that they are the result of the interruption
of afferent impulses passing from the periphery to the cerebellum.
The direction of rotation was towards the side of the lesion after
division of one inferior peduncle, or in other words if, as was always
the case, the left peduncle was divided, the animal rotated like a right
handed screw entering an object. The direction of rotation was
thus the same as after intracranial section of the auditory nerve, and
the reverse of what results on ablation of one lateral half of the
cerebellum. The bulk of the afferent impulses, whose interruption is
responsible for this phenomenon, probably reach the inferior peduncle
from the auditory nerve, but that all the impulses are not derived
from this source was shown by the fact that lateral section of the
medulla below the auditory nerve and its nuclei may result in similar
rotation.
The disorders of motility which followed division of one inferior
peduncle corresponded exactly with those observed after ablation of
one lateral half of the cerebellum. In view of the results obtained
by Claude Bernard, and by Mott and Sherrington, as regards im-
pairment of movement after section of sensory spinal roots, it is
suggested that the defects of movement which result from section of
one inferior cerebellar peduncle may be due to the interruption of
such afferent impulses passing to the cerebellum, rather than to the
cutting off of efferent impulses from the cerebellum to the spinal
centres, The way in which the sensory defects correspond in dis-
tribution to the motor, and the fact that recovery of sensory conduc-
tion commences before any improvement in motor power can be
detected, are held to support this view.
Cutting off of some afferent impulses can alone be considered
responsible for the ocular displacements met with. These displace-
ments correspond with those which are the result of ablation of one
lateral half of the cerebellum, the displacement of the globes being
downward and to the opposite side from the lesion. The displace-
ments following lateral section of the medulla were the same; but
after division of the posterior columns and their nuclei on one side,
the displacement of the globes was downward and to the side of the
lesion.
Spasm, which was easily detected in the back and neck muscles on
the side of the lesion, causing incurvation of the vertebral axis to that
side, alone furnished any satisfactory information in support of the
of Afferent and Efferent Tracts of the Cerebellum. 201
possible control which the cerebellum may exert on the spinal centres.
The state of the knee-jerks afforded no satisfactory information on
this point.
The blnnting of sensibility met with is held to be further proof
that the cerebellum is concerned with sensory as well as motor pro-
cesses, as was contended by the author in a former paper,
Faradic excitability of the opposite cerebral hemisphere was found
to be less than of that on the side of the lesion, both when the in-
ferior cerebellar peduncle was divided, and when partial hemisection
of the medulla was performed, leaving the pyramid intact. The
most satisfactory explanation of this phenomenon appears to be that
the removal of some afferent inhibitory influence from one half of
the cerebellum allows this half of the organ to further inhibit
the cortex of the opposite cerebral hemisphere ; an explanation in
keeping with that offered when the results of ablation of the cere-
bellum were under consideration.
This view is strengthened by the remarkable results obtained by
the intravenous injection of absinthe in animals in whom the same
lesions had been previously produced, for with the pyramidal system
absolutely intact on both sides, there was an entire absence of con-
traction of the muscles of the anterior extremity on the side of the
lesion, and diminution of contraction of the muscles of the posterior
extremity on this side, as compared with those of the opposite limb.
Such was the result obtained when the convulsions were induced
soon after the lesion, but when induced at some remote period, such
as three weeks after, the muscles of the anterior extremity on the
side of the lesion contracted, though the contractions were much less
powerful than were those of the opposite anterior extremity, and
were often largely tonic in character.
Transverse section of the posterior columns, and their nuclei alone
on one side, did not alter the character of the absinthe convulsions in
such a remarkable manner as did division of the peduncle and lateral
section of the medulla. After such a lesion the muscular contractions
in the anterior extremity on the side of the lesion were less power-
ful than were those in the opposite anterior extremity, and there was
more tonus and less clonus than in the contractions on the opposite
side. Both these characters were evident in the early convulsion's of
a series, but became much more pronounced in the later convulsions.
The author contents himself with recording these facts, and makes
no attempt to speculate as to their probable significance.
The paper is illustrated by tracings obtained of the muscular con-
tractions resulting from excitation of the cerebral cortex with the
induced current, and from the convulsions evoked by the intravenous
injection of absinthe, and demonstrate the points alluded to in that
part of the text which deals with these phenomena.
202 Mr. W. Heape.
" The Menstruation and Ovulation of Macacus rhesus" By
WALTER HEAPE, M.A., Trinity College, Cambridge. Com-
municated by Dr. M. FOSTER, Sec. R.S. Received June
15,— Read June 18, 1896.
(Abstract.)
The specimens used in the following investigation were collected
in Calcutta in 1891.
Anatomy of the Cervix. — A valve-like structure is formed in the
canal of the cervix by means of three strong folds, one of these folds
fits into a recess formed by the two other folds, and forms a valve
which persists throughout life. It is unlike any other structure of
the cervix with which I am acquainted.
Breeding. — A definite breeding season for Macacus rhesus seems to
be proved, but it is equally certain that in different parts of the
Continent of India the breeding season occurs at different times of
the year.
Menstruation. — A congestion of the skin of the abdomen, legs, and
tail, a swelling and congestion of the nipples and vulva, and flushing
of the face, are all prominent external signs of menstruation. A
regular menstrual flow occurs consisting of a viscid, stringy, opaque
white fluid filled with granules, and containing also red blood
corpuscles, pieces of uterine tissue, both stroma and epithelium, and
also leucocytes.
The following classification of the various stages passed through is
adopted : —
A. Period of rest. Stage I. The resting stage.
B. Period of growth. Stage II. The growth of stroma.
Stage III. The growth of vessels.
C. Period of degeneration.
Stage 1Y. The breaking down of vessels.
Stage Y. The formation of lacunae.
Stage YI. The rupture of lacunae.
Stage VII. The formation of the menstrual
clot.
D. Period of recuperation.
Stage VIII. The recuperation stage.
The surface of the uterine mucosa, which is smooth and semi-
transparent during Stage I, becomes swollen and opaque during
Stage II. and flushed during Stage III ; it then becomes highly con-
gested, Stage IV, and dark red spots, due to the formation of lacunae,
appear on the surface in Stage V ; when Stage VI is reached, free
The Menstruation and Ovulation of Macacus rhesus. 203
blood is found in the uterine cavity ; the menstrual clot is formed
during Stage VII, and the torn mucosa is healed in the final, Stage
VITI.
Histology. — The uterus consists of an internal mucosa and external
muscular layers ; the mucosa is composed of uterine and glandular
epithelium, blood vessels, and stroma. The uterine epithelium lines
the surface of the stroma, the glandular epithelium lines pits in the
stroma and is continued into branches of those pits which extend
from their lower end into the deeper part of the stroma.
The stroma itself is a delicate connective-tissue-like layer ; the
internuclear protoplasm is drawn out into delicate processes which
form a continuous network, and there is no intercellular substance.
The histological changes which take place during the menstruation
of Macacus rhesus are very similar to those which I have already
described in a former paper, *' The Menstruation of S&mnopithecus
entellus ('Boy. Soc. Proc.,' vol. 54, and 'Philosophical Transactions,'
vol. 185). Work similar to that which I have already described for
S. entellus has been undertaken for Macacus rhesus, and the phenomena
compared step by step. While it has been thought advisable to note
the points of similarity and of difference which occur in the menstrua-
tion of these two species, and to point out the fact that the results
arrived at by the study of the menstruation of Macacus rhesus entirely
confirm the results which my examination of 8. entellus led me to
publish, I have purposely avoided all unnecessary repetition and have
been obliged in consequence to assume some knowledge of the details
given in my former papers. It is all the more important to publish
this account, as the results which I have arrived at differ in some
important particulars from the accounts of menstruation which have
been generally accepted.
Stage I. — The mucosa of Macacus rhesus is thicker and the proto-
plasmic network denser, the glands more numerous and more
branched than is the case in 8. entellus. I find no radial fibres.
Stage II. — There is a great increase in the number of nuclei by
amitotic division and fragmentation. Hyperplasia occurs. The
mucosa becomes much swollen.
Stage III. — The vessels increase in number and size, and they are
congested. There is an increase of leucocytes.
Stage IV. — Hypertrophy of the walls of the vessels in the super-
ficial part of the mucosa, followed by degeneration, occurs ;
the small vessels break down and extravasation of blood takes
place. There is no sign of the migration of leucocytes.
Stage V. — Lacunaa are formed at first some distance below the
epithelium, but they gradually displace the intervening tissue
and come to lie directly below the uterine epithelium.
VOL. LX. Q
204 Mr. W. Heape.
Stage VI. — The uterine epithelium degenerates and ruptures, and
the blood contained in the lacunae is poured into the uterine
cavity.
Stage VII. — Denudation follows, and the formation of the mucosa
menstrualis takes place in the same way and to the same
extent as in S. entellus.
Stage VIII. — The recuperation takes place as in 8. entellus. With
regard to the new uterine epithelium I find fresh evidence in
support of my contention that it is formed, not solely from
epithelial elements which already exist, such as the torn
edges of glands, but also directly from elements of the stroma
tissue.
Ovulation in Macacus rhesus. — Only one case has been met with
in which it can possibly be supposed that ovulation and menstruation
have occurred simultaneously ; this is the only case in which a
recently discharged follicle was found in the ovary of a menstruating
Macacus rhesus ; it does not follow that ovulation in this case was
brought about by menstruation ; indeed, the absence of any sign of
the recent bursting of a follicle in any other of the seventeen cases
examined is in itself strong presumptive evidence that the two pro-
cesses are distinct.
This result may be confidently asserted for Macacus rhesus during
the non-breeding season ; at the same time it must be remembered
that I have not investigated Macacus rhesus during the pairing
season ; probably at that time ovulation may be more frequent, and
may more often be coincident with menstruation ; but, however that
may be, menstruation occurs in Macacus rhesus regularly with-
out ovulation taking place, and my former views are confirmed,
namely, that ovulation does not necessarily occur during each men-
strual period, and that it is not necessarily brought about by
menstruation.
I feel warranted in going further than this and asserting that the
regular occurrence of menstruation without ovulation, even though
it be in the non-breeding season, is sufficient evidence that ovulation
is a distinct process, and that it depends upon a law or laws other
than the laws which govern menstruation.
The Discharged Follicle. — The changes undergone by the discharged
follicles of Macacus rhesus during the non-breeding season are of
interest. Very shortly after rupture the follicle is pear-shaped, and
the place where rupture took place is to be seen in sections.
The wall of the follicle is composed of branched cells which, along
the inner edge of the follicle, are longitu dinally disposed and form a
denser layer sharply defining the wall from the central cavity.
The cavity contains a network of densely granular material and no
blood clot.
The Menstruation and Ovulation of Macacus rhesus. 205
Hypertrophy now takes place, the wall becomes much thickened
and folded, and a growth of cells takes place from the wall into the
cavity of the follicle, the sharply marked boundary of the wall is lost,
and the long protoplasmic processes of the cells within the cavity are
continuous with the cells of the wall.
The vessels of the wall now become enlarged and increased in
number. Hypertrophy is no longer evident ; the tissue is denser and
shrunken, and the whole structure is reduced in size. Gradually the
cavity of the follicle is also reduced in size, and the tissue contained
therein becomes denser until it is hardly to be distinguished from
that composing the wall. *
Finally the whole of the cellular remains of the follicle consist of a
comparatively small mass of cells with no trace of the follicle wall
and no central cavity, a nearly solid mass of tissue, in the midst of
which a few blood vessels run. The cells which compose this mass
now scarcely differ from the ovarian stroma cells ; they have gradu-
ally undergone the change, and instead of branched cells they now
appear as polyhedral cells or multinucleated polyhedral protoplasmic
masses with intermediate finely branched connective tissue elements
bounding them.
This structure is surrounded by a layer of fine nucleated fibres ;
but soon these disappear, and the remains of the follicle are no longer
distinguishable from the rest of the ovarian stroma.
Throughout, no trace of a blood clot within the follicle was seen,
and therein these ruptured follicles differ from what is usually de-
scribed as a normal ruptured follicle in the human female. This
difference between two animals, both of which undergo menstruation,
is remarkable and worthy of special attention.
I have some reason to believe the difference may be due to the
presence or absence of the breeding season in monkeys, and to
periods in the human female, which are in the one case favourable,
and in the other case not favourable, to conception.
If this be true, the period of the human female which is unfavour-
able to conception would be comparable to the non-breeding season of
monkeys, and the period favourable to conception with the breeding
season of monkeys.
It is not maintained that among civilised peoples at the present
day there are definite breeding and non-breeding times, but the com-
parison is in harmony with the view that at one period of its exist-
ence the human species had a special breeding season.
VOL. LX.
206 Drs. W. Ramsay and J. Norman Collie.
"The Homogeneity of Helium and of Argon." By WILLIAM
RAMSAY, Ph.D., F.R.S., and J. NORMAN COLLIE, Ph.D.,
F.R.S. Received July 21, 1896.
Preliminary.
It was pointed out by Lord Rayleigh and one of the authors that it
is a legitimate conclusion to draw, from the found ratio between its
specific heat at constant pressure and that at constant volume, that
argon is a monatomic element (* Phil. Trans.,' 3895, A, p. 235). A
similar deduction can be drawn regarding helium (' Chem. Soc.
Trans.,' 1895, p. 699). And as the molecular weight of hydrogen is
accepted as twice its atomic weight, and as the density of helium is
approximately 2, and that of argon approximately 20, the molecular
weights of these elements are approximately 4 and 40 respectively.
If, however, the molecule is identical with the atom, then the atomic
weights must also necessarily be 4 and 40.
Bat argon, with an atomic weight of 40, finds no place in the
periodic table of the elements, if, as is usual, it is contended that the
elements must necessarily follow each other in the numerical order of
their atomic weights.
Certain suppositions may be made which would obviate this diffi-
culty. First, the evidence from the ratio of the specific heats may
lead to a false conclusion. But it is inconceivable that any struc-
ture, except one of the simplest kind, should transform all energy
communicated to it as heat, into kinetic energy of translation.
Still, before a final decision on this point is arrived at, it would be
well to a.ctually determine the specific heat of argon, and this will
shortly be done. It may, however, be mentioned, that preliminary
experiments have shown it to be much lower than that of hydrogen,
air, or carbon dioxide, volume for volume.
Second, helium and argon may consist of a mixture of monatomic
with diatomic molecules. The perfectly normal expansion of these
gases appears to negative this supposition ('Phil. Tra'ns.,' loc. cit.,
p. 239, and « Roy. Soc. Proc.,' vol. 59, p. 60). Even at a tempera-
ture of — 88° there appears to be no marked tendency towards
association. It is true that the ratios of the specific heats do not
quite reach the theoretical number I1 66 7. That found for helium
was 1'652, and that for argon T659, with the most carefully purified
samples. Assuming (what there seems good ground to doubt) that
the last decimal place may be trusted, helium can be calculated to
contain nearly 7 per cent, of diatomic molecules, and argon rather
more than 3 per cent. If this calculation be permitted, the atomic
weight of helium would become 4'02, taking its found density at
The Homogeneity of Helium and Argon. 207
2*15, and of argon 38'62. This would place argon below potassium,
the atomic weight of which is 39'L However, it must t>6 acknow-
ledged that such refinements in calculation are far from trustworthy.
Third, helium and argon may each consist of a mixture of two
or more elements. This view has been expressed with regard to
helium by Professors Bunge and Paschen (« Sitzungsber. d. Akad. d.
Wissensch.,' Berlin, 1895, pp. 639 and 759), on the ground that the
lines of its spectrum can be shown to belong to two distinct series.
The question whether argon is a mixture or not was discussed in
the memoir by Lord Rayleigh and one of the authors (Zoo. cit.9
p. 236). It is with this possibility that the present communica-
tion has to deal.
Two methods suggest themselves as suitable in order to ascertain
whether argon and helium are mixtures of two or more elements,
or are single elements. The first is fractional solution in water;
the second fractional diffusion. The second method is obviously
the better calculated to yield the desired data ; for if these gases
contain constituents of different density, diffusion is an infallible
means of separating them.
Description of Diffusion Apparatus.
After a number of trials, the stem of an ordinary tobacco-pipe
was found to yield the best results. Plaster of Paris is too porous,
and various forms of graphite tried did not effect so rapid a sepa-
ration of two known gases as unglazed clay. In fact, nothing
could have been more satisfactory than this apparatus.
It consists of a reservoir for the gas, A, into which projects a
piece of the stem of a tobacco-pipe, B, sealed at the lower end in
the flame of an oxy-hydrogen blowpipe. When the stop-cock C
is open, and D and E shut, the gas in A must pass through the
pipe-clay tube on its way to the reservoir of the pump F. The fall
of the mercury in the tube G, read on the scale H, is timed, about
8 cm. fall being taken as sufficient for the purpose. The mercury
rises in A, and falls in the reservoir I during the diffusion. When
the experiment is finished, the gas is pumped out of the reservoir F,
and collected in tubes similar to that depicted at K, and stored in
a frame resembling a miniature umbrella-stand. The stop-cock D
is then opened, and the clip L is shut, and the less diffusible portion
of the gas is pumped out and collected in other tubes, and set apart.
The purity of the gas is ascertained by means of the vacuum tube M.
After all gas has been removed, the stop-cocks C and D are shut; a
new charge of gas is introduced at N, the stop-cock B being opened,
and the operation repeated. After a sufficient amount of the first
diffusate has been collected, it is. again introduced into the reservoir
A, and the process repeated.
E 2
208
Drs. W. Eamsay and J. Norman Collie,
When towards the end only a small amount of gas is available,
the process may be modified by raising the reservoir I, and so dimi-
nishing the volume of A. The clip L is then closed, and the gas is
allowed to diffuse as before, but the volume in A is kept constant.
The rate of diffusion can be compared with that of hydrogen under
precisely similar circumstances.
In all the experiments the temperature did not alter by more than
a degree or two ; as the object was to effect a separation, and not to
make accurate determinations of the rates of diffusion of gases,
careful regulation of temperature was unnecessary.
Determination of the Ratios of Diffusion of Gases of known Purity.
(a) Hydrogen. — The time required for the column of mercury in H
to sink through 8 centimetres, starting always from the
same level, was found in three experiments to be (1) 433",
(2) 420", and (3) 437" ; the mean is 430". The average
rate per millimetre is 5'37".
(6) Oxygen. — The time which pure oxygen, made from permanga-
The Homogeneity of Helium and Argon. 209
nate, took to diffuse to the same extent was 1719", giving an
average rate per millimetre of 2T49".
(c) Acetylene. — The gas was prepared from pure calcium carbide
by the action of water. It dissolved completely in alcohol.
The time required for diffusion was 1550", giving a rate per
millimetre of 19-37".
Assuming the times for the diffusion of these gases to be pro-
portional to the square roots of their densities, we have —
For oxygen _ _ 2l-39". Found 21-49".
\/l-0082
For acetylene 5'37"* ^13'008 = 19-29". Found 19-37".
A/I -0082
This process may therefore be trusted to give fairly accurate
results when applied to test the rates of diffusion of gases of known
purity.
The Separation of a Mixture of Gases.
To ascertain whether a separation could be easily effected, experi-
ments were made (a) on a mixture of oxygen and carbon dioxide,
and (6) on a mixture of hydrogen and helium.
(a) Oxygen and Carbon Dioxide. — The original mixture contained
36 per cent, by volume of carbon dioxide. It was split into two
approximately equal portions ; each of these was again split into
two. The most diffusible part contained 30'2 per cent, of carbon
dioxide, and the least diffusible part 41 '0 per cent.
(6) Hydrogen and Helium. — The original mixture contained 50 per
cent, of each gas, and its volume was 38 c.c. 19 c.c. were diffused ;
this was again halved, 9*5 c.c. being passed through the pipe ; and
finally another diffusion of the 9'5 c.c. yielded 4*12 c.c. of mixed
gases. The hydrogen was removed by explosion with oxygen.
This mixture now consisted of 67 per cent, of hydrogen and 33 per
cent, of helium.
From these experiments it is seen that a partial separation of such
gases is easily carried out.
The Fractional Diffusion of Argon.
Four hundred c.c. of argon, newly circulated over red-hot magne-
sium until spectroscopic traces of nitrogen were carefully removed,
was diffused according to the subjoined scheme : —
210 Drs. W. Ramsay and J. Norman Collie.
More diffusible. I Less diffusible.
The densities were determined by weighing.
These numbers show that no important separation has been
effected. The difference in density of the two portions may possibly
be attributed to experimental error. When the density of the heavier
portion was taken the weather was damp, and we have found it difficult
to obtain concordant results under such circumstances, owing doubt-
less to the uneven deposition of moisture on the surfaces of the bulb
and its counterpoise. But as it stands, the difference is an extremely
minute one, and it may, we think, be taken that any separation of
argon, if effected at all, is very imperfect.
The Fractional Diffusion of Helium.
Two hundred c.c. of helium from fergusonite of density 2'13 were
separated into two nearly equal portions by diffusion. The rate of
diffusion was 7*14" per millimetre as a mean of two experiments,
giving 7'13" and 7'15" respectively. The most diffusible portion of
this gas gave the rate 7'12" per millimetre. The more diffusible
half of this gas had the rate 7'48", and the least diffusible of the
remainder 7 '38", the temperature being lower. A second specimen
of helium from mixed sources, samarskite, fergusonite, broggerite, &c.,
which showed the nitrogen spectrum strongly, gave a rate for the
first portion of 8'29". This half on rediffusion had the rate 7'64",
and the residue of 8'39", showing that a separation was being effected.
The heavier residue of the remainder from that portion which
showed the rate 8 "39" was too small to make it possible to diffuse it
by the usual method. A second method was therefore resorted to,
and it was directly compared with hydrogen under the same circum-
stances. While hydrogen took 12'14" per millimetre, the residue
took 21*00", and calculating its density from these rates, we have —
21-00")2x 1-0082 QAO
(12-14'T
This would correspond, if it be granted that the impurity is nitro-
gen, to a percentage of 8'5 of that gas. This residue showed a
The Homogeneity of Helium and Argon. 211
strong nitrogen spectrnm ; and the nitrogen was removed by sparking
with oxygen in presence of soda, until the spectrum attested its
absence. (It will be remembered that 0*01 per cent, of nitrogen is still
visible under moderate pressures, * Eoy. Soc. Proc.,' vol. 59, p. 265.)
The rate was again measured against that of hydrogen under pre-
cisely similar conditions, and it was found that while hydrogen took
20*00" for diffusion, this specimen of helium took 28*28". And calcu-
lation shows its density to be now 2*015.
These experiments were sufficient to show, we think, that while it is
possible to separate nitrogen from helium, even although the former
is present in only small amount, we had not succeeded in separating
helium itself into two portions of different densities. If, then,
helium were a mixture, its constitutents must possess nearly the same
density. In no case was any alteration of the spectrum to be
noticed ; the diff usate and the residue were similar, and showed all
the well known lines of helium with the usual intensity.
But it was deemed advisable, in view of the importance of the matter,
to undertake a much more elaborate set of experiments. The helium
was carefully purified from hydrogen and nitrogen by circulation
over magnesium, copper oxide, phosphorus pentoxide, and soda lime,
until a small quantity admitted into a vacuum tube in connection
with the circulating apparatus showed no spectrum either of hydro-
gen or nitrogen, even at a comparatively high pressure, when these
gases are more easily detected. The helium was then fractionated in
a manner exactly similar to that shown in the graphic scheme for
argon (p. 210). The rates of diffusion of the two samples of gas
were then measured.
More diffusible portion —
Time of diffusion reduced to 0° 662*5"
Hydrogen 492*3"
Density, calculated from rate ....,,.. 1*826
Less diffusible portion —
Time of diffusion 654'9"
Hydrogen, at same temperature 484*4"
Density, calculated from rate 1*842
The density of hydrogen was taken as 1*0082, on the standard,
oxygen = 16.
These samples were next weighed.
More diffusible portion —
Volume of globe 16*2*843 c.c.
Pressure at filling 668*5 mm.
Temperature 19*20°
Weight 0*02450 gram
Density 2'049
212 Drs. W. Ramsay and J. Norman Collie.
Less diffusible portion —
Volume of globe 162*843 c.c.
Pressure at filling 663'8 mm.
Temperature 19'93°
Weight 0-02902 gram
Density 2'452
Tlie less diffusible portion was next subjected to the process of
removing nine-tenths, the remaining tenth being collected apart.
This process was repeated three times, so that any portion of gas less
diffusible than the main bulk should thus be left as a residue. From
the more diffusible portion nine-tenths was also diffused out. The
more diffusible portions were then mixed, and the density was again
determined.
Volume of globe 162'843 c.c.
Pressure at filling 765' 7 mrn.
Temperature 20'98°
Weight 0-02801 gram
Density „ . 2*057
This number is practically identical with that previously obtained,
viz., 2-049.
It was of interest to follow the less diffusible gas, so as to ascertain
what impurity caused its higher density. Another set of fractiona-
tions was therefore carried out, and after five separate processes,
in each of which a residue was left, and that residue further diffused,
so as to separate all light gas as completely as possible, a few c.c.
of gas were collected, in which the spectrum of argon was strong.
Now we are certain that at no stage in the operations was any con-
siderable quantity of air admitted by leakage. It may safely be said
that the total amount of air could never have exceeded 5 c.c. And
inasmuch as the density of samples of helium from various sources,
which had undergone very little handling, differed by small amounts,
varying between 2*114 and 2'181, this must be ascribed to contami-
nation with argon, contained in the mineral from which the helium
had been obtained. Every effort was made to detect any unknown
lines in the spectrum of the residue, but in vain. With the jar and
spark-gap, the blue spectrum of argon was visible, and was compared
with that from a standard tube.
If thus the increased density is due to argon, it is possible to calcu-
late the proportion of the latter ; first, in the lightest gas of density
2*117 found in samarskite ; second, in the residue in which the argon
had been concentrated, possessing the density 2*452, on the assump-
tion that helium possesses the density 2'042. The first must contain
0*42 per cent, of argon ; the second, 2'28 per cent.
The Homogeneity of Helium and Argon. 213
The rate of diffusion of the gas of density 2*057 was determined
.finally, so as to afford a check on its density. It took 657*9" for a
quantity to diffuse ; while the same volume of hydrogen under pre-
cisely similar circumstances took 492'3". Reducing these numbers
to density, if hydrogen be taken as 1*0082, the helium possesses the
density 1*801, which compares very favourably with the number
already found, 1*826.
As a final check on these results, a sample of helium from an
entirely different source, samarskite, was so diffused, that first nine-
tenths were removed by diffusion ; from the residue nine- tenths was
again removed, and the process was repeated a third time. The
more diffusible portion was tested as regards rate; while hydrogen
took 492*3" to diffuse, this sample took 652*6". Stated as density,
ths number is 1*771.
The actual density was next determined, with the following
result : —
Volume of globe 162*843 c.c.
Pressure at filling 691*6 mm.
Temperature 19*85°
Weight 0-02567 gram
Density 2*080
This number closely coincides with the density of the previous
specimen, freed from argon by diffusion ; and in this case it must be
remembered, no systematic process for separating two possible con-
stituents was carried out, but the heavier portion only was removed.
The heavier gas separated by diffusion was examined for argon, and
it was possible to see the green group of five lines, but not the red
lines. And with a jar and spark-gap, argon could just be detected.
The rate of diffusion of this gas, which, stated as density, gives the
number 1*8, differs from the density determined by weighing, viz.,
2*08, or thereabouts. This might be caused (1) by a lighter portion
passing over first during diffusion, leaving a heavier portion behind •.
or (2) by the hypothesis that the rate of diffusion of helium is ab-
normal ; and helium has already shown such very remarkable pro-
perties in relation to refractivity for light, and conductivity for
electricity, that the hypothesis is not unwarrantable. The first
supposition, however, is the more probable, and was put to the test
in the following manner.
A smaller apparatus was made for measuring the rate of diffusion
of 10 to 20 c.c. of gas ; and the rates of the sample of density 2*08,
and of the less diffusible residues from this sample were determined.
Both the hydrogen and the helium were carefully measured and
diffused under precisely similar conditions. While the hydrogen took
181" to diffuse, the helium of density 2*08 took 246*6", implying a
214 Drs. W. Ramsay and J. Norman Collie.
density of T871 ; and the residue diffused in 266' 6", which corre-
sponds to a density of 2%187. In each of these experiments about
half the helium passed through the porous plug.
The denser portion of this gas was again diffused five times, lighter
portions being removed. This corresponds to a residue of 30 c.c.
from 400 c.c. of the original gas. The rate of diffusion of this sample
compared with that of hydrogen was almost identical with the last,
namely 208" to 143", and corresponds to a density of 2*133. The
gas is therefore not increased in density by this process.
The lighter gas was submitted to a similar fractionation, and the
ratio of its diffusion-rate to that of hydrogen was 24675" to 181 -0",
as a mean of several closely concordant experiments. This corres-
ponds to a density of 1*874. We have accordingly : —
Density.
" Heavy " portion 2*133
" Light " portion T874
Not content with this, we pushed fractionation still further ; the
helium was divided into seven portions (by fractionation) and then
submitted to methodical fractional diffusion, in which the heavier
portions were transferred to the " denser " side, and the lighter
portions to the " lighter " side. This process was repeated four times,
and the end portions were each divided into two ; the lighter portion
of the "lighter" was collected separately, and its rate determined.
It took 258*5" to diffuse, compared with 189*5" for an equal volume of
hydrogen ; its density calculated from these rates was 1*876. It is
clear, therefore, that the limit has been reached in purifying the
lighter portion by diffusion.
It should have been mentioned that the portion of 2*133 density as
well as that of T874 density had been sparked with oxygen in
presence of potash, and in a vacuum tube showed mere traces of
hydrogen, every other gas being absent. The spectrum of hydrogen
is still visible, even when 0*01 per cent, of that gas is present.
At various times during the attempt to separate helium, the spec-
trum has been carefully examined. The very first portions of the
lightest gas gave an identical spectrum, seen with a hand-spectro-
scope, with the very last portions of the heaviest gas. Professor Ames,
of the Johns Hopkins University, has however kindly undertaken to
photograph the spectra using a dispersion -grating ; so that if any
difference can be detected, it will ere long be made known.
Lord Rayleigh was so kind as to measure the refractivity of these
extreme portions of the fractionated gas. His process has been
described in the ' Proceedings,' vol. 59, p. 202. For the sample of
helium sent him in July, 1895, he found the number 0*146. The
lighter portion of the fractionated gas of density 1*876 had a refrac-
The Homogeneity of Helium and Argon. 215
tivity, compared with air as unity, of O1350 ; the heavier portion, of
0*1524. The ratio of these numbers is very nearly that between the
densities of the gases, viz. : —
0*1350 1-876 , 1-876
00824 = 2018' m8tead °f MM '
Conclusion.
It must be remarked that the rate of diffusion of helium is too
rapid for its density measured by weighing. There can be no doubt,
we think, that the density of the lighter portion, instead of being
1-874, would be, if actually weighed, 2'05 or 2*08. And the heavier
portion has doubtless a proportionately higher density. But, assum-
ing that the densities calculated from the diffusion-rates are correct,
the densities of the two gases, supposing that two exist, are T871.
and 2*133, respectively.
Also, we must not omit to state that careful experiments were made
with the more rapidly diffusing gas to prove that the first portions
passing over did not diffuse at a more rapid rate than the later por-
tions, no difference in diffusion rates, compared with those of hydrogen
under the same circumstances having been detected.
That helium, then, consists of a mixture of two or more distinct
gases is one solution of the problem, probably the one which recom-
mends itself at first sight. But there is another, so revolutionary
in its character that much must be done before it can be regarded
as even worthy to be entertained. So much has, however, been lost
to science by what may be termed scientific incredulity, that we
regard it as well worth putting to a rigorous proof.
It is that a separation has been effected of light molecules from
heavy molecules ; that, in fact, a gas — in this case helium — is not
constituted entirely of molecules of the same weight, but that the
mixture of molecules which we term helium have weights which
average 2"18, or whatever the density of ordinary undiffused helium
may ultimately be found to be. The same supposition would, of
course, be applicable to oxygen, nitrogen, or any gas. In separating
such molecules from each other a practical limit must necessarily be
reached, and this limit appears to have been reached with helium.
There is negative and positive probability in favour of this sug-
gestion. First, no gas has been submitted to methodical diffusion
with a view to effect such a separation, argon excepted ; and here,
too, there is faint evidence of a similar kind. It is proposed to carry
out similar experiments with gases of undoubted homogeneity
according to the usual views ; and till such experiments have been
made, it is impossible to decide the point definitely.
Second, Mr. E. C. C. Baly's experiments on oxygen appear to
216 Prof. W. N. Hartley. On the Spectrum of Cyanogen
point to a similar conclusion ; although no great alteration in density
has been produced, yet there is a sign that a kind of separation is
being effected electrically. There is also in favour of the supposi-
tion the unlikelihood that two or more gases, so like one another as
the constituents of helium, should exist with densities so near each
other; and the probability that some separation should have been
detected by aid of the spectroscope.
Lastly, the refractivities of both gases, if there be two, appear
to be equally abnormal ; now, different gases have different refrac-
tivities in no known relation to their densities, as, for example,
hydrogen O5, oxygen nearly 1. But the refractivities of the dif-
ferent portions of helium are proportional to their densities ; a
statement which is true of any one gas, inasmuch as refractivifcy is
directly proportional to pressure, i.e., mass in unit volume. The
refractivity of helium, also, is so small that it totally differs in this
respect, as, indeed, it does in most of its physical properties from
every other gas, and it is moreover a monatomic gas. Tt is therefore
permissible to seek for an explanation of its remarkable properties in
framing any hypothesis which admits of being put to the test.
"On the Spectrum of Cyanogen as produced and modified
by Spark Discharges." By W. N. HARTLEY, F.R.S., Royal
College of Science, Dublin. Received July 13, 1896.
The Production of Cyanogen in the Electric Arc. — The very careful
and numerous experiments of Liveing and Devvar* have very
generally been accepted as affording evidence sufficient to establish
the existence of an emission spectrum of cyanogen as distinct from
that of carbon in the electric arc. Kayser and Runge,f though at
first disinclined to accept such a conclusion, obtained additional
evidence by experimenting with the arc in air, and in carbon dioxide.
They found that the ordinary carbon spectrum and that of cyanogen
appeared with rapidity alternately in the arc in air, though there
could be no difference in temperature sufficient to account for the
production of two different carbon spectra. With the poles immersed
in carbon dioxide no such changes were seen, the carbon spectrum
alone being visible, which evidence led them to concur in the views
of Liveing and Dewar. The chief evidence of the existence of a
cyanogen spectrum rests on the fact that this substance is actually
synthesised in the arc when nitrogen is present, and because without
* ' Roy. Soc. Proc.,' vol. 30, pp. 152—162, 494—509 : vol. 34, pp. 123—130 and
pp. 418—429.
f " Ueber die Spectren der Elemente. Z welter Abschnitt. Ueber die im galva-
trischen Liclitbogen auftretenden Bandenspectren der Kolile." ' Abh. K. Preuss.
Ak. Wiss.,' 1889, p. 9.
as produced and modified by Spark Discharges. 217
nitrogen, elementary carbon does not yield the same spectrum, no
matter what the temperature may be ; and lastly, that cyanogen gas
burns with a flame of which the banded spectrum is known as that
uf cyanogen by reason of the foregoing facts. Furthermore, I have
found by recent experiments that when a condensed spark is passed
between electrodes of gold in an atmosphere of cyanogen, the same
spectrum is photographed.
If we admit that under conditions favourable to synthesis from its
elements, cyanogen is capable of emitting a spectrum of its own, this
emission should occur only at the moment of its formation, but while
giving consideration to this view we are met by the difficulty that
the flame of cyanogen burning in oxygen would less probably emit
a spectrum of the compound substance itself, which is being burnt,
than a spectrum of the products of its combustion, or of the
separated elements of which it is composed, which are nitrogen and
carbon ; and for this reason, that the process it is passing through is
not a synthetical but an analytical one. Indeed it has been shown
by Liveing and Dewar* that when cyanogen is exploded with oxygen
it gives a bright continuous spectrum, but no cyanogen spectrum, or
carbon bands, or carbon lines.
I shall have to refer to these facts and adduce later evidence of the
existence of the cyanogen spectrum in the latter part of this paper.
Evidence derived from their Spectra, of the progress of Chemical
Changes in Flames. — In support of the view that the flame of burning
cyanogen ought to exhibit the spectrum of carbon, I may mention
the following facts which have been recorded during a very careful
examination of a number of photographs of the spectra of flames
which were obtained by burning gases under normal atmospheric
conditions.
The majority of these photographs were taken in 1882.
The Combustion of Compound Sub- Components of the Spectra photo-
stances, graphed.
Hydrocarbons in oxygen. Carbon bands, cyanogen bands, water-
vapour lines.*!"
Sulphuretted hydrogen in air and in Sulphur bands and water-vapour lines,
oxygen.
Ammonia in air. Water-vapour lines.
Carbon disulphide in air. Sulphur bands only.
Carbon disulphide and nitric oxide. Sulphur bands only.
Carbon monoxide and oxygen. Continuous spectrum of carbon mon-
oxide. Faint lines due to carbon,
very few in number.
* l Roy. Soc. Proc.,' vol. 49, p. 222. " On the Influence of Pressure on Flames."
f When nitrogen is present, Liveing and Dewar have observed the formation of
N02 (loc. cit.).
218 Prof. W. N. Hartley. On the Spectrum of Cyanogen
By the combustion of ammonia in oxygen, water vapour lines are
produced, and new bands and groups of lines attributed by Eder and
Valenta to ammonia. Some of these are, however, due to a compound
other than ammonia.
It will be observed that compounds during combustion as a rule
show the spectra of one or other of their constituents, or of both. In
the case of hydrogen compounds they show the product of the com-
bustion of hydrogen, which is a substance of great stability, and can
therefore exist at a high temperature.
In the nitric oxide and carbon disulphide spectrum, the sulphur
bands, which are very strong, probably obscure those of carbon.
There is a strong continuous band of rays which would likewise serve
to obscure them.
C. Bohn* has examined the spectra seen in a Bunsen burner of the
form devised by Tecluf (which is simply a modification of that
described by Smithells), and compared the spectra with that obtained
by Swan, and with the discharge in Geissler tubes containing various
hydrocarbon gases. He concludes that it is impossible to define a carbon
band spectrum, as the differences observed were greater than could
be accounted for by alterations in temperature and pressure. He
also states that sulphur, hydrogen, and carbon disulphide, also
carbon monoxide, were burnt, but that all these flames yielded con-
tinuous spectra. This statement is incorrect, or at least inaccurate. J
Bohn's observations were evidently made on too limited a region of
the spectrum, and without the aid of photography. On Bohn's paper
Eder has made some observations, quoting both his measurements
in the visible and ultra-violet spectrum, which he observes must have
been unknown to Bohn.§
He describes in what manner and by what causes the edges of the
carbon bands are altered in position or in character.
The observations of Eder on the spectra of hydrocarbon flames are
quite in agreement with those previously communicated by me to the
Royal Society on the oxyhydrogen flame spectrum and the oxy-coal
gas spectrum.
On certain Chemical Changes occurring in the Spark and in Flames.
Though it is now accepted as a fact that the arc in air yields the
spectrum of cyanogen, and that the evidence of this is, first, the
identity of certain bands observed in the flame of burning cyanogen
* ' Zeitschrift fur physikal. Chemie,' vol. 18, p. 219, 1895.
f ' J. prak. Chemie ' [2], vol. 52, pp. 145—160, 1895.
J " .Flame Spectra at High Temperatures " (' Phil. Trans.,' A, vol. 185, pp. 161
—212, 1894).
§ " Ueber Flammen und leuchtende Q-ase " (' Zeitschrift fur physikal. Chemie,
vol. 19, p. 1, 1896).
as produced and modified by Spark Discharges. 219
with those seen in the arc ; second, that these bands cannot be due to
the effect of an alteration in temperature, giving rise to a second
spectrum of carbon ; nevertheless, as I have elsewhere pointed out,*
cyanides in a condensed spark do not produce this spectrum, no
matter whether they are extremely stable cyanides, such as that of
potassium, or those of the most easily decomposable character, such
as mercuric cyanide. This appeared to me to mark the inadequacy
of the facts derived solely from observations on the arc, to establish
the existence of a definite cyanogen spectrum. Moreover, it was
shown that lines somewhat resembling the edges of cyanogen bands
are seen when graphite poles are moistened with water and the
spark is passed through air; these lines are intensified and developed
into bands when the water contains ammonium chloride, calcium
chloride, or zinc chloride, and the bands become stronger as the solu-
tion used is more concentrated.
If the lines observed are the edges of bands belonging to the
cyanogen spectrum, by what means do the chlorides give rise to their
production ? No one has yet supplied the answer to this question,
neither has it been proved that these lines in the spectrum of graphite
are the edges of cyanogen bands, though Ederf and Valenta state
that they are such because the wave-length measurements are
approximately the same.
I believe that I am now able to offer an explanation of the action
of the concentrated solutions of chlorides, and to prove in addition,
that the bands and lines are really due to cyanogen and not to ele-
mentary carbon.
If hydrochloric or any other mineral acid be carefully tested, it is
found to contain ammonia. The only ammonia- free acid is sulphur-
ous acid freshly prepared by passing sulphur dioxide gas into water,
carefully freed from ammonia and from any possible contamination
with it. If from the usual samples of so-called pure mineral acids,
salts of calcium or zinc be prepared, the ammonia salt present is not
eliminated, but it goes into solution and crystallises out with such
calcium or zinc compound, or, if the salt does not crystallise, it
remains in solution, and, as a consequence, the salt will show in its
solution the effect of a larger proportion of ammonium salt, accord-
ing to its degree of concentration. Hence if the bands, said to be
cyanogen bands, are due to the nitrogen of the ammonia present, the
spectrum of the graphite poles will exhibit the bands more strongly,
as there is less water in the solution. But this does not account for
* ' Phil. Trans.,' vol. 175, p. 49, Part I, 1884, and ' Boy. Soc. Proc.,' vol. 55,
p. 344, " On Variations observed in the Spectra of Carbon Electrodes, and on the
Influence of one Substance on the Spectrum of another."
t 'Wien, Akad. Wiss. Denkschriften,' vol. 60, 1893, "Line Spectrum ,of
Elementary Carbon."
220 On the Spectrum of Cyanogen produced by Spark Discharge.
the fact that the spark does not show the- cyanogen bands when
cyanides are submitted to its action. In this case it is possible that
the temperature is too high, and that the cyanogen is decomposed,
possibly by oxidation, for there can be no doubt that such condensed
sparks are at a higher temperature than that of the arc. We know,
too, that several metals are oxidised when volatilised in the spark, if
not entirely at least partially.* But by using gold electrodes with
the cyanides we do not obtain even a carbon spectrum.
Here again, possibly, the carbon is oxidised, and we know that
carbon dioxide in carbonates yields no spectrum of carbon, nor any
lines peculiar to carbon dioxide.
I have sought in every direction for a reasonable explanation of
that which, up to the present, has proved inexplicable, in order that
by working on some hypothesis one might devise a means of putting
the matter to experimental proof. This has now been accomplished
in the following manner.
An almost saturated solution of pure crystallised potassium
cyanide was put into a tube fitted with graphite electrodes in the
manner described in a previous communication.f
The apparatus was fitted into a horizontal wooden tube with a
window of quartz at one end, and carbon dioxide was passed into the
tube until filled. The spark was then passed for five minutes, and
again for ten minutes, a photograph being taken of the two spectra.
The instrument used gave a dispersion equal to four quartz prisms.
A glass tube with a similar window of quartz was fitted with gold
electrodes and filled with cyanogen gas, and another spectrum was
photographed. A fourth spectrum was then obtained by passing
cyanogen into the wooden tube containing the graphite electrodes ;
after the carbon dioxide had been expelled by air and replaced by
cyanogen, the Ll'tube was filled up with the solution of potassium
cyanide. In all four cases the principal group of the cyanogen
bands was obtained, but it was not very strong. A flame of cyano-
gen was then photographed with exposures varying from one to two,
five, and ten minutes. A beautiful series of spectra was obtained,
and the lines belonging to the edges of bands constituting the prin-
cipal group were found to coincide exactly with those photographed
from the potassium cyanide solution when the spark was passed in an
atmosphere of carbon dioxide and in cyanogen, also when the spark
was passed between gold electrodes in cyanogen. These appear to
be the bands referred to by Eder and Valenta, which were described
as carbon lands% when graphite electrodes were used with the spark
* ' Boy. Soc. Proc.,' TO!. 49, p. 448, " On the Physical Characters of the Lines in
the Spark Spectra of the Elements."
f ' Phil. Trans.,' vol. 175, p. 49, 1884.
J Hartley and Adeny, ' Phil. Trans.,' vol. 175, p. 63, Part I, 1884.
Variation in Portunus depurator. 221
in air. From the modification of their appearance, and the measure-
ments originally made from them, their identity was not quite
apparent, although probable.
It thus appears that, with the spark, the cyanogen spectrum is
nothing like so strongly marked, as is the case with the flame of the
gas, only one group of bands being represented, and that when the
spectrum is taken in air the cyanogen does not appear, because in
all probability the substance is oxidised.
I have already stated that the formation of cyanogen which yields
the characteristic spectrum is a synthetical operation, that compound
substances, when burnt in flames, do not, as a rule, emit the spec-
trum of the compound, but the spectrum of one or more of the
elements of which it is composed, or that of one or other of its
products of combustion.
How then are we to account for the cyanogen spectrum in the
flame of burning cyanogen ?
The conditions under which combustion takes place are these :
there is an excess of the gas, the temperature of the flame is exceed-
ingly high, and the gas within it is not in contact with a solid sub-
stance, hence immediate decomposition does not occur, and the
gaseous compound is heated to incandescence.
" Variation in Portunus depurator" By ERNEST WARREN, B.Sc.,
Demonstrator of Zoology at University College, London.
Communicated by W. F. R. WELDON, F.R.S. Received
July 1, 1896.
The following measurements were undertaken at the proposal of
Professor W. F. R. Weldon, and to him I am greatly indebted for
many suggestions, and for the kindly help he has always so readily
given me.
The crabs were obtained from the Biological Station at Plymouth,
and sent at intervals during a period of about two years, dating from
the autumn of 1893. Only males were measured. Seven measure-
ments were made on each individual, corresponding to those made by
Professor Weldon on the female of Garcinus moenas (' Roy. Soc. Proc./
vol. 54).
1. Carapace length, AB (fig. 1).
2. Total carapace breadth, CO'.
3. Frontal breadth, DD'.
4. Right antero-lateral, AC.
5. Left antero-lateral, AC'.
6. Right dentary margin, CD.
7. Left dentary margin, C'D'.
VOL. LX. R
222
Mr. E. Warren.
The total number of crabs measured was 2300. The determina-
tions were made with compasses and a 3-decimetre ivory scale divided
into half millimetres. The measurements were recorded to the tenth
of a millimetre. As a test of accuracy, fifty crabs were indiscrimi-
nately taken out of a large number which had previously been
measured; these were remeasured, and the results compared with
those before obtained. It was found that the mean difference between
any two measures of the same dimension was 0'107 mm.
FIG. 1. — Portunus depurator <? (Plymouth, 1893-95).
A
Continuous outline represents a crab with carapace length AB = 28'5 mm. Dotted
outline represents a crab with carapace length AB = 46*8 mm.
Since the crabs were growing, and so varied much in size, it was
necessary to reduce the measures to percentages of some standard
dimension. The carapace length (AB) was selected, and all the
measurements are expressed as thousandths of this dimension.
The first point to ascertain is whether the mean of the different
" organs " varied as the crab increased in size. To determine
this, the crabs were sorted into groups, according to the length
of their standard dimension, then the arithmetic mean was found
for the remaining six dimensions. In each group the change
in length of carapace was comparatively small, and had to be
neglected. The following table gives the results which were thus
obtained : —
Variation in Portunus depurator.
223
w a |<
r1 *-
? ? 3 «
CO CO CO CO
II
£ fc
I*
W S c-
I i
CO CO CO CO
O CO
I? £?
IP
OO 00
ri ri F* O ^J «-H »-*
|<S2§ I ^ 9 7* •?
/N-t /v\ *V* r*\
3s
CO CO M
•«*< o
9 9s
CO IN
CO CO CO
s s
S 8 § £ S S
s s
CO CO to
oo co r^
1C »-H OO
«£» O CO,
<N O 1^ CO I-H
s s
i« —i >-l
CO CO CO
IP
II
1 s
i I
iO •* -H O CO O
,-H CO ^ O O -H
.2
if
s §
? ?
i I
II
'
S c^
I J
III
-«
'
<? « »
•^ i-c ^
P* CO CO
i i4
§ a s
IO «3
:ji
i
i 1
99
4 i
S 3
a 9.
224 Mr. E. Warren.
As an example we may take the total breadth. Here the observed
range of variation is from 1370 to 1227 thousandths of the standard.
The unit of deviation employed is 0'004 of the carapace length ; thus,
with this unit the range of deviation in the total breadth is expressed
by the number 36. The crabs varied in absolute length of the
standard from 20'0 — 48'6 mm., and in the fourteen groups the
means are expressed in thousandths of carapace length, but the
errors of mean square and all the constants that will hereafter be
given are expressed in terms of the above unit of deviation.
The length of the standard is taken as a criterion of age ; this
may, of course, be only roughly true, and it seems quite possible that
the somewhat large fluctuations which are observed in the means are
due to the groups being in reality slightly heterogeneous by including
crabs of somewhat different ages.
On glancing down the means of the several dimensions, it will be
seen that a state of equilibrium is nowhere reached except perhaps
in the case of the total breadth; thus, throughout life the crab is
gradually changing its shape. This species, like the closely allied
Garcinus moenas, is probably sexually mature when only some 20 —
30 mm. long ;* hence, when all its organs are in a rapid state of
change the crab can propagate its species. Here is an argument, so
it would seem, against the transmission of acquired characters, for
otherwise the earlier broods would tend to have a somewhat different
shape to the later ones, and this is scarcely probable. To illustrate
this change in shape fig. 1 was prepared. The continuous outline
represents a crab with carapace length = 28'5 mm. ; the broken out-
line is the same crab when it has grown to 46'8 mm. ; the angle
CAC' opens out by about a degree. This, of course, is only true on
the supposition that natural selection has not occurred with respect to
these dimensions. The error of mean square of each group is given
in the columns to the right of the means. This constant we take as
a measure of the variability of an organ, and in no case is there a
distinct tendency for it to diminish as we pass down to the groups
containing the older crabs, while in the dentary margins there is an
obvious increase. Hence, at the present period in the life of the
species we have no evidence of selective destruction with regard to
the dimensions here discussed. It is possible, however, that all the
dimensions are really more variable as the crab grows older, but that
this greater variability is concealed by the action of natural selection
in all cases except in the dentary margins.
We will now treat each organ separately.
Total Breadth. — On referring to the table, it will be seen that
groups 4 — 14 have means which remain * fairly steady, and show
* This point is now being investigated. Female Carcinus occurs in berry when
only some 20 mm. long.
Variation in Portunus depurator.
225
4
226 Mr. E. Warren.
no marked tendency either to rise or fall. With these 1923 indi-
viduals a cnrve of frequency was drawn (fig. 2). Its constants
were calculated by the method employed by Professor Karl Pearson
(' Phil. Trans.,' vol. 186). Range of variation = 1227—1370 thou-
sandths of standard, unit of deviation is 0*004 of carapace length ;
therefore the observed range = 36 units, reckoning from 1227
upwards.
Centroid vertical (= position of arithmetic mean) = ] 9*102964.
The second moment about the centroid (/tg) = 26*400476.
Standard deviation (error of mean square), a = ^ ' /JLZ = 5*138139.
Third moment (^) = 0*681766.
Fourth moment (^4) = 2203*762099.
ft, which is rfltf = 0-000025 ; ft = mltf = 3*161849.
The critical function 2ft— 3ft— 6 = 0*323623 is positive, and so the
theoretical curve has an unlimited range.
Professor Pearson's measure of skewness for a curve of unlimited
range is given by the formula
here r =
2ft-3ft-6
Here r = 40*080434 and skewness = 0*002262. It is clear from the
values of the constants that the generalised probability curve would
not differ perceptibly from the symmetrical normal curve, where
ft = 0 and ft = 3.
The areal deviation of the curve of observation from the normal
curve is only 5*1 per cent, of the whole area.
Frontal Breadth. — It will be seen from the table that throughout
the life of the crab the mean of this dimension falls steadily ; as the
crab grows the forehead becomes relatively shorter. On this account
it is difficult to obtain a satisfactory idea of the distribution of devia-
tions. The means of groups 6 — 7 do not differ widely, and so with
these the constants of variation were calculated. The observed range
throughout the whole series was 640 — 795 thousandths of standard,
and so there are 39 of our units of deviation. The range in groups
6 — 7 (including 460 crabs) was 648 — 747 thousandths, that is, 2&
units.
Centroid = 13*791305. ^ = 11*236156.
<r = 3-352036. K = 2*800794.
to = 442*572048.
ft = 0*005529. ft = 3*505490.
r = 15*084346. Skewness = 0*02845.
He re again the critical function 2ft— 3ft— 6 = 0*994393 is positive
Variation in Portiinus depurator.
227
and so the generalised probability curve would be one of unlimited
range.
R. Antero-lateral. — The mean fluctuates considerably in the different
groups, but there is a slight tendency to fall. Omitting the first
group as being too small, it will be seen the mean falls about one
unit in the whole series.
Range of deviation = 732 — 831 thousandths of standard, giving
25 units of variation. We select groups 6 — 12 (1432 individuals) for
forming a frequency curve. Here the range = 736 — 819 thousandths,
giving 21 units.
FIG. 3.— B. Antero-lateral. 1432 Individuals (see fig 2).
Centroid = H'331704. p* = 9 296165.
ff = 3-048978. /IB = -1-075979.
/*4 = 255-659399.
ft, = 0-001441. fa = 2-958381.
r =-6(^»— A"1) - 134-096687.
3/^-2/32+6
Skewness =
= 0'01955.
228 Mr. E. Warren.
The critical function 2ft— 3ft— 6 =—0*087561 is negative, and so
the theoretical curve has a limited range. The calculated range was
71*313123 units, and the observed range 21 units ; thus they differed
very widely. The range on the positive side of the origin was
31*658658, and on the negative side 39*654465. As the frequency
curve is very symmetrical, Professor Pearson's generalised curve with
limited range and symmetry was taken,
where y0 = 186*357143. a = 35*656561.
m = 66*048343. .
The distance of maximum ordinate from centroid vertical is 0*0596,
and this could not be indicated on the scale of diagram. Both this
and the normal curve are drawn over the curve of observation
(fig. 3). The generalised curve differs exceedingly little from the
normal one, the areal deviations in the two cases being 7*7 and 7*5
per cent, respectively.
The flat top to the frequency curve made it at first seem prob-
able that the curve was really the resultant of two normal ones.
It was attempted to resolve it into its constituents by means of Pro-
fessor Pearson's equation of the ninth degree ('Phil. Trans.,'
vol. 185). There were three real roots to the equation; two gave
quite inappropriate solutions; the third gave a negative group of
sixty crabs (with standard deviation = 1*450), having its maximum
ordinate situated at —1*337 from the centroid, and a positive group of
1492 crabs (standard deviation = 3*012), with maximum ordinate at
— 0*0540. The selection of crabs so close to the mean would scarcely
seem to correspond to any natural phenomenon, and the resultant
curve, which was the difference of the two normal curves, fitted the
curve of observation but very little better than the normal or skew
curve in fig. 3, the areal deviation being 7*0 per cent.
L. Antero-lateral. — Here the range of the mean is somewhat larger
than on the right side, being about 1£ units. The range of deviation
in the whole series is 720 — 823 thousandths. A frequency curve was
drawn (fig. 4) with groups 6 — 12, where the range was 724 — 819
thousandths, giving 24 units.
Centroid = 14*046787. ^ = 9*127467.
a = 3*021170. ^ = -1*885642.
p* = 263-267646.
ft = 0-004676. ft = 3*160072.
r = 42*246651. Skewness = 0*031099.
Variation in Portunus depurator. 229
K 4.— L. Antero-lafceral. 1432 Individuals (see fig. 2).
The critical function 2ft— 3^—6 = O306116 is positive, and so the
range is unlimited, as was the case with the total and frontal
breadths.
Using Professor Pearson's skew curve of unlimited range, and
putting
x = a tan 0,
we have y = y0 cos Zn Ocr*9,
where y0 = 152-4817. v = 4-550107.
m = 22-123325. a = 19-291468.
The distance of axis y from centroid = 2'077756, and the distance
of maximum ordinate from centroid = 0'093918. Both, this and the
normal curve are drawn, and there is but very little difference
between them, the areal deviations being 7*5 and 7'9 per cent,
respectively.
B. Dentary Margin. — The mean has a range of about 3£ units, and
it rises as the crab grows. The total range of deviation = 436 — 539
thousandths. As in the other cases, groups 6 — 12 were selected, and
a frequency curve drawn ; the range is 436 — 531 thousandths, giving
24 units.
230
Mr. E. Warren.
Centroid = H'504888. p* = 12-483682.
a = 3-533226. ^ = 1'936527.
fn = 451-998740.
fa = 0-001927. y32 = 2-900359.
r = 55-546793. Skewness = 0*023589.
The critical function 2y32— 3^— 6 = —0-205063 is negative, and so
the theoretical curve has a limited range. This range is 53'325 ; in
the actual statistics it is 24, and so here as in the case of the*
R. antero-lateral it much exceeds any conceivable limit that may
exist for the crab.
L. Dentary Margin. — The trend and range of the mean resemble
those of the R. dentary. The total observed range of deviation is
417 — 524 thousandths. In groups 6—12 the range is 425 — 524,
giving 24 units.
2 = 12-061035.
t = -4-649576.
Centroid = 14-071229.
a = 3-472903.
/i* = 438-990665.
ft, = 0-012322. fa = 3-017770.
r = 8438-070126. ' Skewness = 0-055527
The critical function 2fa— 3# — 6 = — 0'001426. From this
see that the theoretical curve has a limited range ; but this range
would be enormous, and the curve would closely resemble a normal
curve.
Correlation of the Organs. — Out of the six organs discussed, the
frequency curves of three of them (total breadth, frontal breadth, and
L. antero-lateral) give theoretical curves of unlimited range, while
the other three (R. antero-lateral, R. and L. dentary margins) give
curves of limited range. In every case the amount of skewness is
small, and the diagrams show that the generalised probability curves
do not give very obviously better fits than the normal curve. The
fact of the R. antero-lateral giving a strictly limited range while the
L. antero-lateral gives an unlimited one, demonstrates that little stress
can be placed upon the type of curve which a series of observations
may yield.
In the present case the curves would appear to be sufficiently
normal to allow us to find Galton's function (known as r) for pairs of
organs. For this purpose we shall employ the modified formula
2 Deviation A x Deviation B
Variation in Portunus depurator. 231
where n = number of individuals, and <TA and <TB are the standard
deviations of organs A and B respectively. This formula has recently-
been shown by Professor Pearson to be superior to the one formerly
used (' Phil. Trans.,' vol. 187).
The correlation surfaces are published as being of permanent value,
and it is believed that such material as this will be of use in the
future in elaborating or modifying the current theory of correlation.
Figs. 5 and 6 represent two r lines. The crosses were obtained by
FIG. 5. — E. and L. Antero-lateral. r = 0'86.
I
Dotted line = the r line inclined to axis x at tan"1 0'86. The continuous line
joining the crosses is the line found on taking E. antero-lat. as subject. The
circles indicate the points obtained when the L. antero-lat. is the subject. The
probable errors of the dimensions are represented by the intervals 1, 2, 3, &c.,
on both horizontal and vertical scales.
232 Mr. E. Warren.
FIG. 6. — R. Antero-lateral and E. Dentary. r = 0'80.
Dotted line is the r line inclined to axis x at tan"1 0*80. The continuous line join-
ing the crosses is the line found on taking the R. antero-lat. as subject. The
circles indicate the points obtained when the R. dentary is the subject. The
probable errors of the dimensions are represented by intervals, 1, 2, 3, &c., on
both horizontal and vertical scales.
taking one dimension as the subject and the other as the relative, then
for every unit of deviation of the subject the mean of the associated
values of the relative was found. The values of the subject and the
associated mean values of the relative are expressed in terms of
their probable errors, and plotted along the axes of y and x respec-
tively. The points indicated by circles were obtained by reversing
the positions of subject and relative.
It is clear that the crosses and circles do tend to lie along a line
Variation in Portunus depurator.
233
inclined at tan l r to the axis of x. The ends of the lines are irre-
gular on account of the impossibility of obtaining a satisfactory mean
to the relative at these points because of the paucity of individuals
near the limits of the range of deviation. One sees that, in these two
cases at least, the correlation surfaces must closely approximate to the
symmetrical normal surface.
Organs.
Carcinus moenas.
Naples race.
Carcinus moenas.
Plymouth race.
Portunus
depurator.
Plymouth.
r.
Probable
error
of r.
r.
Probable
error
of r.
T.
Probable
error
ofr.
Total breadth and frontal
breadth
0-08
0*66
0-50
0-29
-0-23
-0-26
0-76
0-71
0-60
0-0211
O'OIOO
0 -0143
0 '0187
0 -0197
0 -0193
0-0072
0-0086
0 -0117
o-io
0-65
0-55
0-24
-0-18
-0-20
0-78
0-78
0-70
0-0210
0 -0103
0 -0130
0 -0195
0 -0203
0 -0201
0 -0066
0 -0066
0 -0089
0-14
0-67
0-56
0-30
-0-03
-o-oi
0-86
0-80
0-74
0 -0305
0-0082
0 -0107
0 -0270
0 -0314
0 -0314
0-0035
0 -0050
0-0065
Total breadth and E.
Total breadth and E.
dentary
Frontal breadth and E.
Frontal breadth and E.
Frontal breadth and L.
E. antero-lat. and L.
E. antero-lat. and E.
E. antero-lat. and L.
In the above table the 2nd and 4th columns give the values of
Galton's functions which Professor Weldon found for two races of
female Carcinus moenas ('Roy. Soc. Proc.,' vol. 54). The sixth
column gives the values of r obtained for Portunus.
It is quite obvious that there is a marked similarity between the
three columns of figures. The probable errors of r were found by
1— r*
the formula G'6745 =. which Professor Pearson shows will
yXl+r2)
give a close approximation (' Phil. Trans.,' vol. 187). These probable
errors were added to indicate how far the differences in the values of
r are to be regarded as meaning actual deviations in the constants.
The values obtained for the two races of Carcinus differ from one
another nearly as much as they do from the constants of Portunus.
"We have thus proved that the mutual relationships of the organs
measured are almost as closely similar between the two genera Portu-
234 Mr. E. Warren.
nus and Carcinus as between two not very sharply marked off races
of a single species.
Of course a considerable number of such comparisons would bo
necessary before any safe conclusions could be drawn, and the mean-
ing of the differences observed could only be discovered by such a
comparative treatment of a large series of genera. It is probable
that the larger deviations do indicate real differences in the correla-
tion constant, possibly such are associated with changes in habit or
environment. For example, it is conceivable that a crab which
swims might require to be more symmetrical than one that only
crawls between the tide-marks. Portunus does swim to a certain
•extent, and one can see from the table that the correlation of the two
sides of the body is greater in this genus than in the essentially shore-
living Carcinus moenas.
Variation in Portunus depurator.
235
I. Correlation Surface of Total Breadth and E. antero-lateral.
1432 Individuals.
Measurements
.
in thousandths
£
i
CO
s.
t>
tt
i— 1
10
0
ia
s
CD
CO
£
£
S
S8
S5
—
05
£
i
0
£
•—i
i— i
10
I—I
05
of carapace
length.
a
1
I
X
1
lO
i
0
i
s
2
ci
1
CD
i
i
I
g
CD
I
I
X
I
X
1
Total breadth.
rf
oo
CO
0
i-H
05
GO
*
CD
»o
*
CO
*
1— 1
O
iH
(M
CO
;
10
CO
t-
X
05
2
1370—1367
17
1
2
17
1366—1363
16
16
1362—1359
15
1
1
15
1358—1355
14
2
1
14
1354—1351
13
1
1
1
13
1350—1347
12
1
2
i
1
2
1
12
1346—1343
11
1
1
i
2
4
1
1
11
1342—1339
10
1
3
2
2
5
1
2
1
10
1338—1335
9
1
1
4
3
5
8
4
1
9
1334—1331
8
1
3
4
5
8
5
5
1
2
i
8
1330—1327
7
2
1
2
6
8
7
12
4
1
7
1326—1323
6
I
2
6
11
15
10
4
6
2
6
1322—1319
5
1
3
4
5
10
10
15
7
7
2
1
5
1318—1315
4
5
15
11
12
17
14
7
5
1
4
1314—1311
3
1
6
14
11
17
29
10
8
4
2
1
1
1310—1307
2
1
1
2
3
8
11
14
22
21
9
10
6
2
2
1306—1303
1
1
2
8
6
15
8
13
14
14
12
8
5
3
1
1
1302—1299
0
3
2
8
16
26
18
21
7
4
3
0
1298—1295
1
1
2
1
7
7
19
16
23
22
20
10
3
1
1294—1291
2
1
3
4
11
9
22
18
16
5
1
2
1290-1287
3
1
2
3
3
7
13
15
16
13
15
6
5
1
3
1286—1283
4
4
5
15
12
12
9
13
4
2
4
1282—1279
5
1
1
4
4
6
8
17
11
7
2
5
2
1
5
1278—1275
6
3
3
7
9
14
6
7
5
2
6
1274—1271
7
4
4
6
9
9
4
2
1
1
7
1270—1267
8
1
2
3
5
1
7
5
2
2
1
1
8
1266—1263
9
2
1
4
2
4
5
2
2
9
1262—1259
10
2
2
1
2
1
4
1
10
1858—1255
11
3
1
1
1
2
3
11
1254—1251
12
1
1
1
1
1
12
1250—1247
13
2
1
13
1246—1243
14
1
14
1242—1239
1.5
15
1238—1235
16
1
1
16
1234—1231
17
17
1230—1227
18
1
18
0
05
GO
^
CD
10
^
00
w
,_,
0
i— i
N
co
>*
IO
CD
^
X
05
o
r->
1— {
236
Mr. E. Warren.
II. Correlation Surface of Total Breadth and R. Dentary.
1432 Individuals,
Measurements
in thousandths
of carapace
length.
i
1
O5
!
?
I
2—455
g
I
1
T
X
7
05
•~o
T
1
rH
(N
T
CO
g
!
rH
rH
VO
2—515
01
rH
cc
g
T
§
i
X
rt
1
3
1
i
%
J§
®
"3
1
§
*
3
3
§
§
§
§
§
rH
lO
rH
10
o
3
<N
Total breadth.
o
rH
05
00
^
to
*
;
CO
"
rH
0
-
*
co
«
,0
CD
*>
GO
O5
O
rH
rH
rH
2
co
rH
1370—1367
17
1
2
17
1366—1363
16
16
1362—1359
15
1
i
15
1358—1355
14
2
1
14
1354—1351
13
1
1
1
13
1350—1347
12
i
1
3
i
2
12
1346—1343
11
1
2
3
1
1
2
1
11
1342—1339
10
2
3
1
1
3
3
2
2
10
1338—1335
9
1
3
3
3
5
1
5
3
1
2
9
1334—1331
8
1
3
2
6
3
3
2
4
8
3
8
1330—1327
7
i
3
4
4
2
8
6
4
2
3
1
7
1326—1323
6
1
1
3
2
7
10
10
5
6
5
5
1
1
6
1322—1319
5
2
i
1
4
2
4
10
12
9
7
3
5
1
3
1
5
1318—1315
4
rj
5
8
7
12
13
12
12
9
2
2
2
1
i
4
1314—1311
3
i
3
5
10
8
26
13
14
9
8
2
1
1
1
1
3
1310—1307
2
1
2
i
4
6
18
13
17
13
10
12
8
4
1
2
1306—1303
1
1
1
5
5
7
7
16
6
15
11
8
7
5
3
4
2
2
1
1302—1299
0
7
6
7
21
7
17
14
7
11
6
4
1
0
1298—1295
1
1
4
4
9
7
10
17
22
17
17
8
5
5
4
1
1
1294—1291
2
3
3
6
10
12
12
14
17
5
5
2
1
2
1290—1287
3
1
1
1
5
5
12
10
8
18
11
10
5
5
5
1
2
3
1286—1283
4
1
2
6
3
11
12
7
7
9
8
4
2
2
2
4
1282—1279
5
1
1
3
6
7
12
9
6
9
4
3
2
2
3
1
e
tj
1278—1275
6
3
4
4
3
711
8
7
5
3
1
6
1274-1271
7
1
4
9
5
4 5
5
4
1
1
1
7
1270—1267
8
1
1
2
2
5
5
2
1
2
4
2
2
1
8
1266—1263
9
1
1
1
2
4
3
4
1
1
1
1
1
1
g
1262—1259
10
1
3
2
3
1
1
1
1
10
1258—1255
11
1
1
2
1
3
2
1
11
1254—1251
12
1
1
1
1
1
12
1250—1247
13
1
1
1
13
1246—1243
14
1
14
1242—1239
15
15
1238—1235
16
1
1
16
1234—1231
17
17
1230—1227
18
1
18
0
I— 1
05
00
*
CD
10
*
co
<N
«-•
o
rH
(N
CO
*
o
CO
•f1
X
CT.
o
rH
rH
rH
CO
rH
Variation in Portunus depurator.
237
W rH 0 05 00 i><0 0 T* CO <N rH O
rH rH iH
OZ8T— Z98T ZT
ZT
998T— 898T 9T
9T
S98I— 6981 9T
9T
898T— 998T *T
*T
,*98I— T98T 8T
rH rH
8T
098T— Z*8I Zl
rH rH
^ Zl
9*81—8*81 TT
rH rH rH
rH rH u
3*81— 688T OT
rH rH rjl rH
*" OT
888T— 988T 6
rH i— 1 rH
<NrH rH g
*88T— T88T 8
rH rH rH rH CM rH
N 8
088T— Z38I Z
rH CM rH rH CM CO
z
9S8T— 828T 9
rH CM CM CM rH T}< CM
CM g
SS8T— 6T8T 9
rH CM CO rH T}1 rH
<N CM rH rH rH g
8T8T— 9T8T *
CM rH <N CM •* »a I •*
•* CO rH rH ft
*I8I— TI8T 8
rH rH~ rHCOCvJ^O J>
rH U5 CO iH p
OT8T— Z08T Z
rHrH COrH rH rH T* CO *> CM
COCOCOCMrH rH rH n
908T— 808T T
rH rH CM CO rj< 5M CM
(N •* (M CM rH -j-
308I-663T 0
rHCM I-HCMINCMIO rH
rH
O5 CO rH rH rH rH Q
86ST— 96&T T
rH r^ CO CM CM <O 00 CO 1>
COCMCM rH -,-
*63I— I6ST Z
rH iHrHrHrH^T}ICO JCM
CO (N rH CM rH rH n
06ST— Z8SI 8
CM CM CM CO CM *Q
rH CM CO CM CM o
0
9831— 88ST *
rH O CO -^ rH
Tjl CO rH CO (N CO ^
38KT— 6Z3I 9
CM rH rH CO CO CO
CM CM CO rH g
8Z3T— 9ZZT 9
rH rH CM (M CO
<N <N rH rH g
*LZl— ILZl Z
rH rH 10 CM
CO 1<l /
OlZl— Z92T 8
rH iH rH C^l rH rH
CM rH rH rH o
O
99ST— 893T 6
rH CO
CMrH g
Z9ZI— 693T OT
rH rH
^ OT
89SI— 992 [ TT
TT
*9ST— T92T Zl
rH rH
Zl
QQZl— Z*2T 8T
iH rH
8T
9*ST— 8*^T *T
*T
z^zi—mzi 91
9T
883T— 9R2T 9T
9T
*82T— T82T ZT
ZT
Ogjrj — ^^T 8T
rH
8T
•TO^q^ox
rH rH I— 1
rH rH rH
^^ 4
111 *
d S °* J ^
III 5
ll:-S 1
a.s° |
iiimiiiui i
mm
VOL. LX.
238
Mr. E. Warren.
IV. Correlation Surface of Frontal Breadth and R. Antero-lateral.
460 Individuals.
Measurements
1
in thousandths
g
10
05
s
CD
£
10
£
§8
F
rH
05
P
05
o
£
i— i
r?
05
of carapace
length.
1
X
cl
CO
I
00
!
i
I
I
1
7
CM
1
1
1
1
X
T
CO
"i
•<*
iO
lO
to
co
*>
*>
X
X
X
05
O5
o
2
o
rH
Frontal breadth.
s3
3U
X
GO
X
*•
CO
*
*
CO
oq
3
0
H
*
CO
;
*
CO
*-
X
O5
747—744
12
1
12
743—740
11
1
11
739—736
10
10
735-732
9
1
1
1
1
9
731-728
8
1
1
1
2
1
i
8
727—724
7
1
2
1
4
1
1
2
7
723—720
6
1
3
3
4
3
i
1
6
719—716
5
1
1
2
4
3
4
3
5
715—712
4
1
1
1
3
4
5
5
1
1
1
4
711—708
3
2
3
4
3
2
5
10
5
5
2
1
1
1
3
707—704
2
1
1
3
4
5
10
6
5
9
3
3
5
2
2
703—700
1
3
3
8
4
12
7
8
5
7
3
2
1
699—696
0
2
4
5
7
5
13
3
8
5
2
4
1
0
695—692
1
3
2
1
1
8
6
8
7
2
8
4
2
1
691—688
2
2
3
1
5
1
3
7
8
2
2
2
2
687—684
3
4
1
5
1
2
4
2
3
3
2
3
683—680
4
1
1
2
1
2
2
3
1
1
1
4
679—676
5
5
3
1
1
1
1
5
675—672
6
2
3
3
1
6
671 -668
7
1
1
1
7
667—664
8
8
663-660
9
1
9
659—656
10
10
655—652
11
11
651—648
12
1
12
00
*•
CO
lO
*
co
*
iH
0
iH
*
CO
*
»
CO
fc-
X
O5
Variation in Portumis depurator.
239
V. Correlation Surface of Frontal Breadth and R. Dentary.
460 Individuals.
Measurements
in thousandths
of carapace
length.
f
1
152—455
I
160—463
§
1
1— 1
172—475
cc
|
1
i
M
i
I
1
I
i— i
rH
1
10
AH
Frontal breadth.
rf
*-
«
o
4
cc
*
i— (
0
—
*
CO
«
o
cc
t>
00
05
747—744
12
1
12
743—740
11
i
11
739-736
10
10
735—732
9
1
1
1
1
9
731—728
8
3
2
1
1
8
727—724
7
2
1
1
2
1
3
1
1
7
723—720
6
1
1
2
4
1
2
2
i
1
1
6
719-716
5
1
5
4
1
1
2
2
2
5
715—712
4
1
1
3
4
]
5
4
2
1
]
4
711—708
3
1
1
1
4
3
4
6
2
5
5
3
6
1
2
3
707—704
2
2
4
4
3
4
6
9
6
4
4
6
2
2
1
2
703—700
1
1
1
6
2
1
6
7
7
3
7
6
7
2
2
1
2
1
1
699—696
0
3
3
3
6
3
6
8
5
8
4
3
4
3
0
695—692
1
1
3
3
4
4
2
-
8
4
7
3
4
1
2
1
1
691—688
2
1
1
1
8
1
2
4
2
4
5
3
4
3
1
1
2
687—684
3
1
1
3
1
1
2
3
4
4
2
2
1
1
1
3
683—680
4
1
1
1
2
1
1
2
3
2
1
4
679-676
5
1
3
2
4
2
5
675—672
6
2
,1
1
2
2
'l
6
671—668
7
1
1
1
7
667—664
8
8
663—660
9
1
9
659—656
10
10
655—652
11
11
651—648
12
1
12
**
CO
0
*
CO
<M
rH
0
i— i
*
re
«
10
0
*••
00
O5
T 2
240
Mr. E. Warren.
VI. Correlation Surface of Frontal Breadth and L. Dentary.
460 Individuals.
Measurements
in thousandths
£;»
^
00
(M
iffl
0
o
ID
38
(M
CO
00
oo
X
05
05
g
o
0
of carapace
length.
3
rH
I
^
I
I
r-<
IO
T
co
1
T
I
I
I
T
1
10
I
'ft
^
•^
^
^
^
^•j
i
^
^
C5
°^
o
o
Frontal breadth.
^
05
X
*
CO
•
*
CO
«
I— 1
0
-
0,
CO
*
«
CD
*•
747—744
12
1
12
743 740
11
1
11
739—736
10
10
735—732
9
1
i
1
i
9
731—728
8
1
1
i
2
1
1
8
727—724
7
1
2
2
2
3
1
1
7
723—720
6
2
1
5
2
2
1
1
i
1
6
719—716
5
2
4
4
2
2
1
3
5
715—712
4
1
3
3
2
3
6
2
1
2
4
711—708
3
1
2
4
7
2
3
4
8
5
4
1
2
1
3
707—704
2
3
3
4
5
4
5
10
7
5
6
1
2
2
2
703—700
1
5
5
1
8
6
4
5
8
5
10
3
2
1
699—696
0
1
1
2
3
5
3
4
6
9
8
6
3
6
1
1
0
695—692
1
1
1
1
2
5
6
3
9
5
3
8
4
3
1
1
691—688
2
4
4
2
3
2
3
5
2
4
4
3
2
687—684
3
2
3
1
3
1
3
2
5
1
1
1
4
3
683—680
4
1
1
2
1
2
1
4
2
1
4
679—676
5
1
1
2
2
5
1
5
675—672
6
1
2
1
1
2
1
1
6
671—668
7
1
1
1
7
667—664
8
8
663—660
9
1
9
659—656
10
10
655—652
11
11
651—648
12
1
12
•
05
00
*>
CO
lO
«
CO
«
r- 1
0
*
(M
CO
*
«
CO
*>
Variation in Portunus depurator.
241
VII. Correlation Surface of R. Antero- lateral and L. Antero-lateral.
1432 Individuals.
Measurements
1
in thousandths
•f
£
rH
CO
10
co
CO
%
§
rH
O
S
01
O
CO
CD
cb
^H
£
£
S3
So
rH
Cl
S
%
1
1
rH
rH
10
01
rH
of carapace
length.
o
i
I
ft
el
CD
O?
I
i
3
CM
10
1
s
§
1
3
J>
el
1
^
4<
1
oo
00
1
Cl
I
I
I
!
rH
I
30
B. an tero- lateral.
Hi
co
rH
rH
rH
rH
0
Oi
00
*-
0
0
;
CO
<M
rH
0
rH
*
CO
4
0
CD
«•
00
Oi
8
819—816
10
1
i
10
815—812
9
1
2
l
c
8ll— 808
8
2
\
3
8
807—804
7
1
1
1
2
1
1
7
803—800
6
1
1
3
3
5
7
16
3
6
799—796
5
2
1
13
7
15
29
1
5
795—792
4
2
10
14
19
29
9
2
4
791—788
3
1
1
6
12
21
54
17
5
3
787—784
2
5
12
29
27
82
19
8
2
1
2
783—780
1
1
2
2
9
24
40
62
25
15
3
1
1
779-776
0
1
7
16
37
70
21
16
3
1
0
775—772
1
2
6
13
20
76
26
17
3
1
771—768
2
1
6
16
27
64
25
10
7
2
2
767—764
3
2
10
19
40
19
6
4
3
763—760
4
1
2
3
10
27
8
5
2
2
1
4
759—756
5
1
1
6
21
9
2
5
755—752
6
1
1
6
7
6
1
1
1
6
751—748
7
2
1
1
3
1
7
747—744
8
1
1
2
1
2
1
8
743—740
9
9
739-736
10
1
i
10
CO
rH
rH
•H
O
Oi
00
*
*
0
4
CO
cq
rH
0
rH
<N
CO
4
vO
CD
*>
00
01
0
242
Mr. E. Warren.
VIII. Correlation Surface of R. Antero -lateral and B. Dentary
1432 Individuals.
Measurements
1
in thousandths
of carapace
length.
1
1
cc
T
1
T
T
'N
456—459
1
1
r-H
!
5
476—479
1
1
rH
1
1
I
1
1
rH
g
1
H
s
1
CD
rH
520—523
Si
\a
i
B. Antero-lateral.
rH
rH
s
05
00
*
CO
o
;
CO
«
-
O
rH
«
CO
«
10
CO
1>
CO
O5
o
rH
3
IN
rH
819—816
10
2
10
815—812
9
1
1
1
1
9
811—808
8
2
2
2
8
807—804
7
1
3
1
2
?
803—800
6
1
3
5
11
7
6
4
2
6
799—796
5
1
2
g
8
11
8
13
10
10
1
l
5
795-792
4
6
11
11
20
16
12
5
3
1
4
791—788
3
3
5
5
16
22
23
21
10
8
3
1
3
787—784
2
1
i
4
16
18
33
41
32
25
10
4
2
783-780
1
1
1
5
12
21
24
42
32
17
13
9
5
2
1
779—776
0
1
5
10
17
32
36
36
16
11
6
1
1
775-772
1
1
.1
3
6
16
22
36
27
32
13
i
2
1
1
771—768
2
3
8
22
24
30
30
20
13
6
2
2
767—764
3
6
17
13
19
16
14
8
5
2
3
763—760
4
5
6
5
14
17
8
•
2
1
4
759—756
5
2
3
9
11
6
c
3
1
5
755-752
6
2
2
2
4
9
5
6
751—748
7
1
1
3
1
1
1
7
747—744
8
;
2
2
1
1
1
8
743—740
9
9
739—736
10
1
10
rH
o
rH
05
00
*
CO
0
«
CO
•M
rH
0
rH
aq
CO
4
0
CO
«>
CO
05
O
rH
rH
rH
(M
rH
Variation in Portunus depurator.
243
IX. Correlation Surface of R. Antero-lateral and L. Dentary.
1432 Individuals.
Measurements
in thousandths
£»
X
$
£
o
2
oo
o
in
o
|
oo
cq
CO
0
rl
00
N
CD
a
•*
50
<M
rH
o
fN
of carapace
1
1
T
\
!
l
T
T
T
1
Tf
1
T
i
I
T
T
T
T
1C
1
T
10
I
1
T
n
i— i
ft
r-l
a
m
rH
rH
-•n
rH
£H
^o
cc
3
3
3
$
«
CO
tr
30
°p
2h
c^
^
o
o
rH
p|
I— 1
$
R. antero-lateral.
^
CO
rH
2
£
2
Oi
00
«>
CO
0
*
CO
0,
rH
o
*
H
CO
*
10
CO
«>
X
Oi
o
rH
rH
rH
819—816
10
1
!
10
815—812
9
2
1
1
9
811—808
8
8
1
1
1
£
807—804
7
1
]
1
3
1
7
803—800
6
1
2
6
8
11
3
6
2
6
799—796
5
2
1
4
11
12
i
10
i
12
2
1
1
5
795—792
4
1
4
12
11
12
20
16
L
3
2
4
791—788
3
1
]
2
c
10
12
24
24
23
8
5
1
1
£
787—784
2
1
'2
8
9
14
25
35
35
19
27
8
2
2
783—780
1
1
1
"L
4
8
18
19
40
28
22
15
14
f
2
1
1
1
779—776
0
a
3
4
17
21
32
32
28
20
12
4
0
775-772
1
1
j
8
9
13
20
36
28
25
12
8
9
1
771—768
2
4
b
9
23
30
31
21
12
9
K
4)
1
c
767—764
3
]
1
3
0
15
16
19
15
13
*
/
0
1
3
763—760
4
]
2
5
1
6
11
11
14
5
*:
^
759—756
5
1
1
-
2
2
10
11
t
5
1
]
i
K
755—752
6
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244 Dr. W. P. May. On the Segmental Representation
"Investigations into the Segmental Representation of Move-
ments in the Lumbar Region of the Mammalian Spinal
Cord." By WILLIAM PAGE MAY, M.D., B.Sc., M.R.C.P.,
Fellow of University College, London. Communicated by
Professor VICTOR HORSLEY, F.R.S. Received July 1, 1896.
(From the Laboratory of the Physiological Institute, Berlin, and the Pathological
Laboratory of University College, London.)
(Abstract.)
Introduction.
The following researches were carried out in consequence of sug-
gestions made to me by Professor Victor Horsley, F.R.S., with the
view of throwing light upon the degree to which certain movements,
or, speaking more precisely, sensori-motor (kin aesthetic) phenomena
are represented in any given segment of the lumbo-sacral region of
the mammalian spinal cord, and further of determining what relation-
ship exists between the representation of one movement and that of
another. Of methods suggesting themselves for this investigation
the one selected was direct excitation of the anterior or posterior
roots or of the spinal cord itself.
Historical Introduction.
A series of laborious investigations has been carried out to deter-
mine the localisation of certain movements and the physiological
relationship of various muscles in and to definite segments of the
spinal cord, by Terrier and Yeo, Bert and Marcacci, Forgue, Sherring-
ton, and Russell, the method of which was limited (controlled by
exclusion experiments) to stimulation of the motor roots. I am
only aware of one antecedent localisation experiment (by S herring-
ton) carried out by stimulation of the posterior roots ; nor can I find
any record of the direct excitation of the surface of the cord for in-
vestigating the localisation of movement.
Method of Investigation and Precautions Observed.
(a) Species of Animal. — The animals chiefly employed were the
dog and monkey (Macacus sinicus and rhesus).
(b) Ancesthetic. — The narcotic agents used were morphia and ether
or, in the monkey, ether alone.
of Movements in the Lumbar Region of the Spinal Cord. 245
Operative Procedure.
Exposure of spinal cord.
Division of cord and isolation of segments.
The cord was exposed with due observation of well-known precau-
tions (Gotch and Horsley, ' Phil. Trans.,' vol. 182, B, 1891). In some
cases the spinal cord and roots were stimulated at first in continuity.
In others, before proceeding to experiment, the spinal cord was
completely divided at from two to eight segments above the part
experimented upon. The spinal roots were divided as detailed in the
paper.
METHOD OP EXCITATION.
I. Electrical.
Apparatus. — A single Daniell cell was used which supplied a Du
Bois Beymond's inductorinm of the usual type, the secondary coil
being 20 cm. or more from the primary. The electrodes attached to
the secondary coil consisted of closely approximated (1 mm.) plati-
num points. The duration of excitation was, as a rule, momentary,
and never exceeded 1 — 2 seconds.
(a) Excitation of Nerve Roots. — The nerve roots were raised in the
air and the electrodes usually applied, so that the direction of the
exciting current was transverse to the nerve fibres.
(6) Excitation of the Spinal Cord. — The surface of the cord was
gently dabbed with small wool swabs, kept in warm saline solution
and squeezed dry, before the electrodes were applied. The duration
of excitation was always brief, rarely exceeding one second.
The value of the method may be estimated by considering the
following facts. On stimulation of the surface of the spinal cord as
already mentioned, movement was always elicited in the leg on the
side stimulated, when the electrode was applied to the surface of the
posterior column, but never, as far as I was able to see, could move-
ment be obtained by the application of this strength or even con-
siderably greater strength of stimulus to the lateral or anterior
columns, when adequate precautions (vide paper) were taken to
prevent the direct spread of the current to the neighbouring root
fibres. The movement elicited from stimulating the posterior
columns was always marked and quite definite, and merely depended
in intensity upon the conditions stated below. For instance, apply-
ing the electrodes to the surface of the postero-external column in
the fifth lumbar segment of the dog on the left side produced lateral
flexion of the spinal column to the same side, flexion and adduction of
the hip, flexion of the knee and toes, and movement in the tail
(flexion to the same side). But the chief result was the very local
effect which could be obtained by varying the point stimulated j thus,
246 Dr. W. P. May. On the Segmental Representation
stimulation of a point 1 mm. centrally or laterally to a given point
often produced an entirely different resulting movement or no move-
ment at all, which fact is clearly of much importance in showing
that, with the above strength of current, the restriction of the
stimulus to one point can be accurately attained.
II. Mechanical.
As a means of controlling the observations derived from electrical
•excitation, mechanical stimulation was sometimes employed in ex-
amining the nerve roots, and was obtained by pinching the tissues
with fine forceps. The results were precisely the same as those
gained by electrical stimulation.
ON THE RESULTS OP DIRECT EXCITATION OF THE SURFACE OF THE
SPINAL CORD IN THE DOG.
I. Gross Localisation.
(a) Area Excitable. — The excitable area of the surface of the cord
itself is the postero-external column. Stimulation of the column of
Goll produced no movement except in the lower lumbar region,
where that column is either very narrow or practically absent, and
where, presumably, the effect was due to the stimulus directly
affecting the fibres of the postero-external column.
(b) Unilaterality. — In the large majority (91*5 per cent.) of experi-
ments on animals (dog, cat, monkey) the fact was strikingly evident
that the movements produced were limited to the side stimulated.
(c) Vertical Extent of the Spinal Cord in the Dog from which move-
ment in the Lower Limb can be obtained. — In the dog, movements in
the lower limb can be produced from stimulation of Burdach's
column from the upper border of the 13th dorsal segment to the
lower border of the 1st sacral segment, and from the results obtained
it will be seen that the various areas in the postero-external column,
the stimulation of which on the surface of the cord produces move-
ments in the limbs, anus, and tail, all overlap one another, but that
on the whole the hip area is a little nearer the cerebrum than that
for the knee, the area for the knee more proximal than that for the
foot, and so on.
(d) Effect of Transversely Dividing the Cord above the Lumbar
Enlargement. — The only effect observed to follow such separation of
the cord from the brain, upon the movements elicited as above
described, was one of increased excitability. The limits described
were found to prevail precisely, and the cord was excitable quite up
to the level of the section.
of Movements in the Lumbar Region of the Spinal Cord. 247
II. Minute Localisation within the Excitable Area.
Repeatedly it -was found that with a minimal stimulus it was
possible to evoke movement either in the tail (and anns) only, or in
the hamstrings, or in the hip or in the side only, and whenever this
was obtained it was an invariable rule that the point for producing
movement in the tail was placed in the cord mesially of that point,
stimulation of which gave movement in the hamstrings, and that
this latter point was mesial of that for the hip, while most external
of all was the point from which movement of the side of the trunk
was elicited. This lateral arrangement has been in part foreshadowed
by the observations of Mott on the relation between the coccygeal
nerves and Goll's column.
Investigation into the Segmental Representation of the Cord by Com-
parison of the Results of Excitation of the Anterior and Posterior
Roots.
(a) Latency of Effect. — Of course, in accordance with all previous
investigations, the delay in passing through the spinal cord was well
marked.
(6) Character of Movement Elicited from the Respective Roots.—
Stimulation of the peripheral end of an anterior root gave, on the
whole, a quick powerful extension of the whole limb, the latency, of
course, being extremely short ; on the other hand, excitation of the
corresponding posterior root resulted in a slower, though strong,
flexion of the whole limb with a well-marked latency.
This remarkable functional distinction between the roots, viz.,
anterior giving extension and posterior flexion, was quite constant, and
was obtained in every animal in which the experiment was made.
Of course, the movement which took place was a resultant effect, and
was produced by the contraction of many muscles, each muscle con-
tracting in whole, or in part, in combination with other muscles to
produce the extension or flexion respectively.
The results with each root are given in the tables.
Further, stimulation of a posterior root (say the 5th) produced
flexion of a joint or joints even when all the neighbouring anterior
roots but one were divided. Hence this flexion can only be due to
I the stimulus passing from the posterior root through the spinal cord
along a particular anterior root to the muscles (differentiation of
function in the nerve centre of that root), yet stimulation of this
same anterior root produces extension.
And this agrees entirely with the results obtained in a different
way by Dr. Risien Russell ('Phil. Trans.,' 1893).
The above experiment also goes to show that stimulation of one
posterior root causes impulses to pass out along many anterior roots.
248 Dr. W. P. May. On the Seymental Representation
A further important condition of the particular function with which
we are now concerned (sensori- motor reflex) is that, from the present
investigation, it seems certain that the path along which the im-
pulses pass as evidenced by movement elicited in stimulating a
certain posterior root, is directed towards a point below the level of
that posterior root, and, not as we might suppose, chiefly in the same
segment, or even above the level at which the posterior root joins the
cord.
The proof of this new conclusion is afforded by many facts given in
the paper, not the least interesting of which is, that on direct stimu-
lation of the second or third anterior lumbar roots in the dog, no
movement results in the lower limb, yet stimulation of the third
posterior lumbar root gives distinct flexion and adduction of the hip
and flexion of the knee, and stimulation of the second posterior
lumbar root gives slight flexion of the hip and knee. In this con-
nexion also results obtained by Claude Bernard, Schiiltze, Ramon-y-
Cajal, Kolliker, Betzius, and Grolgi afford similar evidence.
Influence of the Posterior Roots upon the Nerve Centres in the Spinal
Cord.
It was found that repeated excitation of the posterior roots de-
cidedly increased the excitability of the posterior roots themselves,
of the spinal cord and of the anterior roots. The difference in the
excitability of the preparation before and after the previous stimula-
tion may be represented by the fact that, whereas the minimal
stimulus before the application of the repeated stimulus was repre-
sented by a distance of 50 cm. of the secondary from the primary coil
in the condition of heightened excitability, a minimal stimulus was
obtained at a distance -of 70 cm. On the other hand, by cooling the
posterior roots as suggested by Professor Gad, a converse effect was
produced. The results of Belmonda and Oddi are also quoted in this
connexion.
Results of Experiments upon the Spinal Cord in the Monkey.
Method. — The same as above.
The same general results were obtained by stimulation of the
spinal cord in the monkey as described in the case of the
dog. The area found excitable was the postero-external column,
stimulation of which from the thirteenth dorsal segment to the
second sacral segment inclusive produced after a very short latent
period lateral flexion of the spinal column, flexion and adduction of
the hip, flexion of the knee, ankle, and toes, movement of the
tail and perinceum, and peristalsis (rumbling of the bowels), though
it depended on the position of the electrode and the strength
of Movements in the Lumbar Region of the Spinal Cord. 249
of the stimulus whether only a part or the whole of these move-
ments resulted. Similarly, with regard to the lateral extent of
the areas mentioned above, although, of course, a stroog stimulus
caused movement in all parts named, yet in each case it was quite
definite that the area, stimulation of which produced movement in
the tail, was nearer the middle line than that for the hamstrings,
the area for the hamstrings nearer the middle line than that for
flexion of the hip, and this median of that which caused lateral
flexion of the side. Hence these results demonstrate from a func-
tional standpoint the anatomical arrangement which has been
described by various writers — Ramon-y-Cajal, Kolliker. Grolgi, &c.
As in the dog, the knee jerks were found not only present, but
even exaggerated, after the cord had been completely divided.
Also section of the cord caused increased excitability of the parts
below section, but abolished the movement produced by stimulation
of the first or second or third posterior roots below the level of the
section, and the more oblique the position of the posterior root fibres
in contact with the cord, the greater the interval affected in this
manner.
On the Production of Movement by Stimulation of the Anterior and
Posterior Spinal Roots in the Monkey.
The general results obtained by excitation of the spinal roots in
the monkey were the same as those in the dog. As already known
(Sherrington, Risien Russell) stimulation of the third lumbar to the
first or second sacral anterior roots (inclusive) alone produces move-
ment in the lower limb, yet, on stimulation of the posterior roots of
the twelfth dorsal to the second sacral inclusive, it was found that
movement resulted in the lower limb, and in the latter case the bulk
of the movement produced is that of flexion.
Summary and Conclusion.
1. Relationship of Posterior Roots to Reflex Kincesthetic Centres. — It
appears from the foregoing experiments to be definitely established
that any reflex centre derives its chief afferent impulses from a nerve
root which enters the cord, as a rule, about two segments higher,
i.e., on the cephalic side. This generalisation, established by the
method of excitation, is confirmed by anatomical and pathological
considerations.
2. Lateral Arrangement of Fibres in Burdach's Column. — The fibres
of the postero-external column are arranged in a definite and constant
order from within out, the innermost fibres (i.e., those nearest the
middle line) representing the most distal portions of the tail and
lower limb and the outermost the proximal segments of the limbs.
250 Mr. W. H. Lang. Preliminary Statement on the
3. Whereas direct excitation of the anterior roots in the dog pro-
duces, as a resultant movement, extension of the lower limb, the
resultant movement produced from the kinoesthetic centres of excita-
tion of the posterior roots is always flexion. In the monkey there is
not this apparent antagonism, because stimulation of the anterior
roots in that animal brings out a differentiation of flexion and exten-
sion, although excitation of the posterior root gives flexion alone.
"Preliminary Statement on the Development of Sporangia
upon Fern Prothalli." By WILLIAM fl. LANG, M.B., B.Sc.,
Lecturer in Botany, Queen Margaret College, and Robert
Donaldson Scholar, Glasgow University. Communicated
by D. H. SCOTT, M.A., Ph.D., F.R.S., Honorary Keeper of
the Jodrell Laboratory, Royal Gardens, Kew. Received
September 14, 1896.
The observations recorded in this paper were made in the course of
an investigation into the relation existing between variability in the
fern plant and apogamy in the prothallus. This research was under-
taken at the suggestion of Professor Bower, F.R.S., and has hitherto
been conducted in the Jodrell Laboratory, Royal Gardens, Kew.
To Dr. Bower and Dr. Scott I am indebted for valuable assistance
and advice.
In two of the species investigated, Scolopendrium vulgare, L., and
Lastrcea dilatata, Presl., sporangia were borne upon the prothallus.
In the former they were sometimes associated with apogamous
development of the sporophyte, the details of which differ, however,
from previously recorded cases of apogamy. As a considerable
period must elapse before an amount of material sufficient for the
complete study of details of development can be obtained, it appeared
advisable to describe the results obtained from the material at
present available. Cultures are about to be commenced in the
Glasgow Botanic Gardens for the further study of these abnormal
prothalli.
The prothalli of the two species investigated will first be de-
scribed, and the theoretical bearing of the results briefly considered.
Lasfrcea dilatata, PresL, var. cristata gracilis, Roberts.
The spores from which the cultures of this fern were made were
obtained from a plant in the collection of Mr. C. T. Druery, F.L.S.,
who kindly supplied me with material. This variety was found
wild in Carnarvon in 1870. Spores were sown in the first week
of November, 1895, upon a carefully sterilised soil, consisting of
Development of Sporangia upon Fern Prothalli . 251
a mixture of vegetable mould and sand. The pot was kept con-
stantly covered with a glass plate, and the necessity of watering
was avoided by standing the pot in a large saucer kept full of water.
A close crop of well-formed prothalli, on which antheridia and arche-
gonia were present, completely covered the surface of the soil. In
April, 1896, a number of the prothalli bore normal embryos in an
early stage of development. Three months later numerous young
plants were present, which were found on examination to be nor-
mally produced.
The prothalli which had not been fertilised had lost the heart-
shaped outline and elongated considerably ; some of them reached a
length of 2 cm., and were 5 mm. in breadth. The archegonia were
very numerous, and were situated upon a distinct cushion, which was
continued in the larger prothalli as a well-marked midrib. They
were arranged in transverse rows ; their necks had opened in a
normal manner, and the canal showed the usual brown discoloration.
Antheridia were present on some of the prothalli.
In some of these prothalli the midrib was continued into a cylin-
drical process of variable thickness. This arose in some examples as
a direct continuation of the apex, but more frequently was attached
to the under surface, just behind the apex of the prothallus ; in one
instance it was found in a corresponding position on the upper sur-
face. The actual apex usually loses its meristematic appearance ; it
grows out as a narrow triangular lobe, which consists of colourless,
cells, and contains tracheides. This lobe closely resembles the
" middle lobe "* found in the apogamous prothalli of certain ferns,
and probably corresponds to it. In a few instances this middle
lobe is formed, but no cylindrical process arises ; in such cases
secondary prothalli are produced from the anterior margin of the
thin lateral wings, and the whole closely resembles an aborting pro-
thallus of Aspidium filix-mas or Pteris cretica. When the prothalli are
seen from above, the anterior edge can be traced across the base of
the cylindrical process. As will be described below, the first spo-
rangia formed on the prothallus are usually situated on this margin,
especially on the " middle lobe." The process is of the same deep
green colour as the midrib. Sexual organs, often in considerable
numbers, are borne upon it. They are usually well formed; the
archegonia open in the usual manner, and the spermatozoids are capable
of active movement when liberated. On other examples variously
malformed sexual organs occur. The abnormal archegonia are
seated upon small elevations composed of cells which contain chloro-
phyll ; sometimes the neck is open, but other examples have the
* Farlow, ' Quart. Journ. Microscop. Sc.,' 1874, p. 268. De Baiy, ' Bot. Zeit./
1878, p. 463.
252 Mr. W. H. Lang. Preliminary Statement on the
neck closed and branched. The central cell of the abnormal anthe-
ridia is arrested at a more or less early stage of development, while
the cells of the wall and the base take on active growth.
The sporangia are either isolated or associated together in groups,
which bear a striking resemblance to sori. They are borne upon the
process or close behind it upon the true middle lobe, and are rarely
found upon prothalli which have not produced a cylindrical process.
When this is the case, they are always isolated and situated on the
edge of a thin continuation of the prothallus arising from the apical
depression.
Single sporangia occur frequently on the edge of the prothallus,
which, as described above, crosses the base of the process. In a
number of examples a single sporangium occupied a median posi-
tion, and, from earlier stages observed, it is probable that it is to be
traced back to the original growing point of the prothallus. In other
cases several sporangia were formed in this region. Isolated spo-
rangia are also found on the process, but more frequently groups are
met with. They occupy the upper or lateral faces of the process,
and whenever sporangia in early stages of development are found,
they are situated on its apex. It is probable that the groups of
older sporangia had become displaced from this position by the fur-
ther growth of the process. The groups were at a considerable dis-
tance from each other.
The relative positions of sporangia and sexual organs is a point
t>f some interest, and was readily determined. Archegonia were
present close to the sporangia, and at the same level on the
process. When the process, after producing sporangia, had con-
tinued its growth, archegonia and antheridia were present on the
portion beyond the sporangia, as well as on the older part, and, in
cases in which more than one group of sporangia had developed, the
intervening region bore sexual organs. Rhizoids are also produced
abundantly from the shaded side of the process, and, so far as exter-
nal appearance is concerned, there is no reason to doubt the pro-
thallial nature of the region on which the sporangia are situated.
The tissue underlying the .sporangia, however, presents peculiarities
in structure which may modify this conclusion to some extent.
Beneath the single sporangia developed on the edge of the prothallus
a few tracheides, which agree in every respect with those present in
apogamous prothalli, were always to be found. Similar elements
were always present in the tissue beneath the groups situated on the
process. It is possible that here, as in the case of the sporangia
upon the prothallus edge, the first tracheides are developed before
the young sporangium can be recognised. All that can be stated
with certainty is that they are already present beneath very young
sporaugia. The tracheides may become connected together into a
Development of Sporangia upon Fern Prothalli. 253
band, resembling a rudimentary vascular bundle, and suggesting a
comparison with the vascular supply of a sorus.
The development of the sporangium could not be followed in
detail in the material obtained as yet, but a sufficient number of
stages have been found to make it clear that there is no difference of
importance from the well known course of development of thd same
member on the sporophyte. In the youngest stage seen the apex
of the sporangium was occupied by a tetrahedral cell, the cells
destined to form the lateral portions of the wall having already
been cut off from a large, dome-shaped terminal cell, the limits
of which were clearly recognisable. This was borne upon a stalk
cell. A tetrahedral archesporium is formed, from which tapetal
cells are cut off. The tapetum subsequently becomes two-layered,
and the central cell developes into a group of sporogenous cells.
From these, in the most mature sporangia found, a number of dark
brown spores had developed, while the tapetum was represented by
numerous granules between the spores. The number of spores
appeared to be the same as was contained in a sporangium developed
on the sporophyte. The sporangium wall was perfectly developed ;
the cells of the annulus showed the characteristic thickening of their
walls, which were of a dark brown colour, and a well formed stomium
was present. When tested with dehydrating agents, the mechanism of
the annulus was found to be perfect. The stalk consisted of four rows
of cells.
JSTo sporangia have been found in which the spores were ripe, but in
.view of the advanced stage of development in those observed, there is
every probability that some may be obtained. It will be interesting
to ascertain if the spores are capable of germination, and if the
prothalli produced show any peculiarities. The spores seen already
possessed a thick wall on which indications of sculpturing were appa-
rent, and a single nucleus was present in each.
When the unnatural conditions under which they developed are
borne in mind, it is not surprising that many imperfect sporangia
were found. Such sporangia were in fact the more numerous. Some-
times the arrest of development had taken place before the tapetum
had originated from the archesporium, but more commonly the double
layer of tapetal cells was present surrounding a sporogenous cell
which had become highly refractive, the nucleus being indistinguish-
able. The annulus could be made out, but its cells were thin walled
and colourless, and the whole sporangium was pale and more flattened
than one of the same age in which sporogenous tissue had formed.
No evidence has yet been obtained of the production of sporo-
phytes, showing vegetative organs upon the cylindrical process, but
one example was seen in which a group of sporangia, situated on the
apex of the process, was surrounded by ramenta.
VOL. LX. u
254 Mr. W. H. Lang. Preliminary Statement on the
Scolopendrium vulgare, I/., var. ramulosissimum, Woll. — The cultures
of this fern were made in the manner already described for Lastrcea
dilatata. The spores were obtained from a plant grown in the open
air in the Royal Gardens, Kew.
The prothalli were at first heart-shaped, and on many of them
normally produced embryos developed. No further changes ensued
in those on which young plants were present, and they soon became
colourless and died. In those which had remained unfertilised, how-
ever, the apex continued directly into a cylindrical process,* which
was of considerable thickness, and in some cases attained a length of
5 mm. The lateral portions of the prothallus showed no further
growth, and became in time brown or colourless appendages to the
base of the cylindrical process. On the process were numerous
archegonia, and its prothallial nature was still further shown by the
presence, in. some instances, of thin lobes of tissue, which generally
bore antheridia. Sections through the process in this stage show
that the archegonia are normally formed, and reach almost to the
apex, and that tracheides are absent from the tissue. The archegonia
are capable of fertilisation, for in some instances normally produced
embryos were found.
After the process has in this manner attained a greater or less
length, its tip becomes yellowish, contrasting with the deep green
colour of the region behind. Near the apex ramenta develope, which
soon completely clothe the tip of the process and render it white and
conspicuous. Archegonia are present to just below the ramenta.
Longitudinal sections at this stage show that one or two small eleva-
tions corresponding to the rudiments of the apex of the stem, and the
first leaf of the sporophyte have been formed. Beneath the broad tip
a flat mass of small meristematic cells extends ; the meristematic
tissue is continuous with that of the stem and leaf apices, but, on
passing away from these, is separated by several layers of large, non-
meristematic cells from the surface. In a slightly older stage the
stem apex has become conical, and a number of leaves have formed
which are circinately curved, and form a bud clothed with ramenta.
In the meristematic mass numerous tracheides have been developed.
One large group is central in position, and extends to the limit
between prothallial and sporophytic tissue, while others are found
beneath the bases of the leaves, and are in continuity with their pro-
cambial strands. The apex of the stem is occupied by an initial cell,
the relation of which to the initial cell or cells of the apex of the
process has not yet been traced. The young sporophyte appears to
be a direct continuation of the process. It is possible that some of
* Prothalli of Scolopendrium, which from the brief description given of them
appear to have borne similar processes, are mentioned by E. J. Lowe, in the ' Gard.
Chron.,' November 10, 1895. They were not investigated further.
Development of Sporangia upon Fern ProthallL 255
the cases of apogamy recorded by Stange* were of this nature, but in
Doodia caudata, R. Br., which is the only one of his species yet
investigated in detail ,f the elevations, from which sporophytes de-
veloped, were situated on the under surface of the prothallus. This
case appears to be intermediate in character between Scolopendrium
and the species investigated by De Bary.J
Several prothalli were found bearing sporangia ; these were grouped
together in large numbers, usually upon the upper surface of the
cylindrical process, but sometimes both above and below. Archegonia
were situated close to the groups of sporangia. In the region of the
prothallus, underlying the group, a strand of tracheides was found ;
in one instance this was connected with a spherical mass of tracheides
developed to all appearance within the venter of an archegODium
whose neck had not opened. The tissue upon which the sporangia
are inserted is thin walled, and its cells have granular contents ; it
contrasts sharply with the cells of the prothallus which have a large
vacuole and walls which stain much more deeply with hsematoxylin.
As in the case of Lastrcea dilatafa, the stages seen render it prob-
able that the sporangia follow the usual course of development. Two
layers of tapetal cells are formed which surround a considerable mass
of sporogenous tissue. Many of the sporangia fail to attain full
development; they remain colourless, and in time wither. A few
have been found, however, with a well developed annulus of a dark
colour; these contained spores which have not, however, been
examined in detail.
In one case two ramenta overarching a group of sporangia were
seen. At first sight it seemed possible that they might correspond
to an indusium, but, when taken in connexion with another example
in which a cylindrical process, which bore sporangia laterally, termi-
nated in an apogamously produced biid, another explanation appears
more probable ; this will be referred to again below.
It is worthy of note that another variety of this species has been
found to produce young plants, the first fronds of which bore
numerous prothalli while still in connexion with the stem.§ The
prothalli on which these plants appeared had been subjected to
repeated subdivision, a process which in other species || has been
found to induce apoganious development of the sporophyte. Unfor-
tunately nothing is known of the manner in which these peculiar
plants of Scolopendrium were produced, but it is possible that they
arose apogamously. The case of Scolopendrium would then be com-
* ( Ber. der Gesellsch. f. Bot.,' Hamburg, 1880, p. 43.
f Heim, ' Flora,' 1896, p. 329.
J Loc. cit.
§ In a paper by Mr. E. J. Lowe, read at the Linnean Society, February 20, 1806.
|| Stange, loc. cit.
256 Mr. W. H. Lang. Preliminary Statement on the
parable to that of Trichomanes alatum* in which apogamy and
apospory co-exist. Prothalli have been found to arise directly from
the older fronds of another variety of Scolopendrium.'f
An attempt will now be made to bring the peculiar modification of
the life-history cycle of these ferns into relation with previously
recorded cases of apogamy, and to estimate its theoretical bearing.
A full consideration of these points must be deferred until more
extended observations have been made.
There seems no reason to doubt the prothallial nature of the cylin-
drical process : its origin, the character of its cells, the presence of
functional sexual organs, the development of rhizoids, and the direct
transition to an ordinary flat prothallns apex sometimes met with, are
sufficient grounds for this conclusion. The distinction between its
origin as a direct continuation of the prothallus, and the cases in
which it arises behind the apex which has lost its meristematic cha-
racter, is not an essential one. Both forms occur in Lastrcea dilatata ;
in the latter case the process may be compared with the numerous
elevations which appear on the under side of old prothalli of Doodia
caudala,$ and are capable of apogamous development. The forma-
tion of such processes by prothalli which have attained a considerable
size without having been fertilised, appears to be of not infrequent
occurrence, and is usually associated with apogamy. It is recorded
in Todea pellucida, Carm., T. rivularis, Sieb.^ and Athyrium filix-
fcemina, B&rnh.,\\ and the writer has found in Aspidium frondosum,
Lowe, as many as six apogamous buds, formed from the tips of
cylindrical processes, which arose from the anterior margin of a
prothallus.
The term cylindrical process^" has been used to avoid confusion
with the middle lobe developed in aborting prothalli of Pteris
cretica and Aspidium filix-m as. This, as De Bary has shown, may be
regarded as corresponding to some extent with the first leaf of an
apogamous sporophyte.** A structure comparable with this middle
lobe has been found in prothalli of Lastrcea dilatata, which had also
produced a cylindrical process ; usually one or more sporangia were
borne upon it.
Tracheides were always present in the tissue beneath sporangia,
* Bower, 'Annals of Botany,' rol. 1, p. 300.
f Druery, 'Linn. Soc. Jouru.,' vol. 30, p 281.
J Heim, loc. cit., p. 340, fig. 12.
§ Stange, loc. cit.
|| Druery, ' Gard. Chron.,' November 10, 1895.
^[ It is impossible to determine whether the structure to which Wigand (' Bot.
Zeit.,' 1849, p. 106) applied this name, and which he inclined to consider as a
rudimentary axis, was of tho same nature or was a true middle lobe, but the latter
appears the more probable conclusion.
** Loc. cit., p. 464.
Development of Sporangia upon Fern Prothalli. 257
and the question arises whether their occurrence is to be regarded as
of morphological significance. They have been found in the pro-
thalli of a number of species of ferns, and, in every case investi-
gated, were associated with apogamy. In the case of Pteris cretica
the differentiation of the tracheides in the prothallus precedes the
origin of the bud.* This is the case also with the single sporangia
formed on the edge of the prothallus, and probably holds good for
the groups of sporangia borne on the process. But tracheides may
occur in the prothallus at a distance from the place of origin of
buds or sporangia. Putting aside the case of the middle lobe, the
prothallial nature of which is open to doubt, a large bundle of tra-
cheides was found in the substance of a fleshy prothallus of a variety
of Scolopendrium vulgare, which bore numerous archegonia on the
sarfaces immediately above and below the traeheides. Elongated
cells, which resemble sclerenchyma fibres, occur in the midrib of cer-
tain frondose liverworts. f A still more instructive example is
afforded by the presence of tracheides in the massive endosperm of
certain cycads. J This latter case shows clearly that such elements
may be formed in the gametophyte to meet a physiological need. Ib
seems inadvisable, therefore, to lay stress on the presence of tra-
cheides as a means of distinguishing between the two generations,
and the more so since their occurrence in a portion of the prothallus
which is about to bear a bud or sporangia can be recognised as a
physiological advantage. Such means of procuring a sufficient water
supply maybe a necessary preliminary to the development of a young
sporophyte or a group of sporangia.
Lastly, it remains to consider the view to be taken of the presence
of the characteristic reproductive organs of the asexual generation
upon the gametophyte, and to consider its bearing upon the nature
of alternation of generations in the archegoniatse. Since the dis-
covery that in certain cases the one generation could arise directly
from the other without the intervention of the proper reproductive
organs, such cases have been used in support of the view that the
alternation in the Archegoniatse was homologous. § On the other
hand, it has been maintained, both on grounds of the exceptional
nature of these cases of apospory and apogamy, and of comparative
phylogeny, that the distinction between the two generations was a
much deeper one ; that the alternation was not homologous, but anti-
thetic. || So far no case has been recorded in which the proper
reproductive organs of the one generation were situated upon the
* Farlow, loc. cit., p. 269.
f Goebel, « Outlines,' p. 145.
J I am indebted to Professor Bower for this unpublished fact.
§ Pringsheim, ' Jahrb. f . Bot.,' bd. 9, p. 43.
|| Bower, ' Annals of Botany,' vol. 4, p. 347.
258 Mr. W. H. Lang. Preliminary Statement on the
other without the intervention of the vegetative organs. At first
sight such appears to be the case in the prothalli of the two species
described ; sporangia were present in close proximity to the sexual
organs, the vegetative organs of the sporophyte being, at most, repre-
sented by a mass of cells underlying the group of sporangia, and
even this distinction may not be recognisable beneath the single
sporangia on the edge of the prothallus.
Several reasons may be adduced, however, against regarding these
phenomena as evidence that the alternation of generations found in
the ferns is not antithetic. In the first place, it is to be noted that the
two forms in which sporangia have been observed upon the gameto-
phyte are highly variable species, and that the varieties studied were
well-marked crested forms. Further, the conditions under which the
prothalli existed were in several respects unnatural. Among them
the fact that fertilisation was prevented by not watering the cultures
from above, and that a prolonged growth of the unfertilised prothalli
was thereby induced, is of special interest, for it appears that apogamy
is liable to occur under such conditions in ferns which, as a rule,
reproduce sexually. While these considerations do not of themselves
preclude deductions being made from these peculiar forms of repro-
duction, they necessitate especial caution in their use in the discusoion
of broad morphological questions.
Further, a number of reasons exist for considering the production
of sporangia on the prothallus as a special case of apogamy.
In Scolopendrium vulgare a sporophyte may develope from the tip of
the cylindrical process. This may happen after a group of sporangia
has been developed. In one case two ramenta were present, one on
.each side of a group of sporangia; they were in every respect similar
to the ramenta which develope on the tip of the process when it is
being transfprmed into the apex of a bud. Whenever a group of
very young sporangia was seen it was situated upon the apex of the
lobe, and the sporangia were in a more advanced stage of develop-
ment the farther the group to which they belonged was removed
from the apex. This has been most clearly seen in the case of
Lastrcea dilatata in which no buds with vegetative organs have as
yet been seen, although in one case ramenta were associated with the
sporangia, but it also holds for Scolopendrium. The explanation of
these facts, which appears most probable, is that each group of
sporangia had occupied the apex of the process when very young,
and had become farther removed from this position as the process
continued to increase in length. It is uncertain whether this growth
is by direct continuation of the original growing point of the process,
or whether the development of a group of sporangia at the apex
necessitates the formation of a new growing point ; possibly both
forms occur. If the latter be the case a process on which several
Development of Sporangia upon Fern Prothalli. 259
-groups of sporangia are present must be looked upon as a sympodium.
Some probability is lent to this view by the fact that the first-
appearance of the process in Lastrcea is usually as a sympodial con-
tinuation of the axis of a prothallus whose true apex has developed
one or more sporangia.
Since the group of sporangia and the tissue of peculiar character
on which they are seated are developed in the place of an apoga-
mously produced vegetative bud, they may be looked -upon as con-
stituting a very reduced sporophyte. The drain upon the resources
of the prothallus entailed by the production of this reduced bud,
which is incapable of further growth, is much less than when a
vegetative bud is formed. This explains why a number of such
sporangial groups can be produced and supported by a single pro-
thallus. The occurrence of a number of vegetative buds on a single
prothallus is the exception, but may happen, as the case of Aspidium
frondosum, before mentioned, shows.
It is probable that it is in the constitution of the nuclei that a
means of distinction between cells of the oophyte and the sporophyte
must be looked for in these cases in which the two generations are
in intimate connection with each other.*
The complete life history of the fern is in these cases still further
shortened than in the ordinary cases of apogamy ; not merely the
formation of a zygote by the fusion of antherozoid and ovum, but the
formation of an embryo, in which any differentiation of the vegeta-
tive organs can be detected, is omitted, and the sporophyte is reduced
to a mass of tissue which may be compared to a placenta bearing
sporangia. The occurrence of single sporangia upon the edge of the
prothallus may, in the light of the series of stages described, be con-
sidered as a still further case of reduction of an apogamous sporo-
phyte. While this does not altogether prevent the explanation of
the presence of sporangia upon the prothallus from the point of view
of the supporters of the homologous nature of the two generations,
it brings the present case into line with other exceptions to the
normal life-history cycle, whose bearing on the nature of alternation
has been discussed by Bower, f The present case, although more
striking in its appearance, seems, so far as it has been investigated,
to afford no sufficient reason for dissenting from the conclusion at
which he arrived.
It is of interest to note the additional evidence, were such needed,
which these observations afford of the generalization made by
Goebel,J that the sporangium is to be regarded as an organ sui
generis.
* Bower, ' Trans. Bot. Soc. Edinb.,' vol. 20.
t ' Annals of Botany,' vol. 4, 1890, p. 347.
t ' Bot. Zeit.,' 1881, p. 707.
VOL. LX. X
260 Prof. G. B. Grassi. The Reproduction and
From the staff of the Royal Gardens, Kew, I received ready
assistance in many practical matters in the conduct of the cultures ;
my thanks are especially due to the curators, Mr. Watson and Mr.
Nicholson.
November 19, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
Dr. Francis Elgar was admitted into the Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
In pursuance of the Statutes, notice of the ensuing Anniversary
Meeting was given from the Chair.
Mr. Shelford Bidwell, Professor Bonney, and Mr. Horace Brown
were by ballot elected Auditors of the Treasurer's accounts on the
part of the Society.
The Secretary read the Titles of the Papers received since the last
meeting, which, under the new Standing Orders, had been published
(see ' Proceedings,' No. 362).
The following Papers were read : —
I. " The Reproduction and Metamorphosis of the Common Eel
(Anguilla vulgaris)." By G. B. GRASSI, Professor in Rome.
Communicated by Professor E. RAY LANKESTER, F.R.S.
II. " Total Eclipse of the Sun, 1896. — The Novaya Zemlya Observa-
tions." By Sir GEORGE BADEN-POWELL, K.C.M.G., M.P.
Communicated by J. NORMAN LOCKYER, C.B., F.R.S.
III. " Preliminary Report on the Results obtained with the Prismatic
Camera during the Eclipse of 1896." By J. NORMAN
LOCKTER, C.B., F.R.S.
" The Reproduction and Metamorphosis of the Common Eel
(Anguilla vulgaris)" By G. B. GRASSI, Professor in Rome.
Communicated by Professor E. RAY LANKESTER, F.R.S.
Received October 19, 1896. Read November 19, 1896.
Four years of continual researches made by me in collaboration
with my pupil, Dr. Calandruccio, have been crowned at last by a
success beyond my expectations, that is to say, have enabled me to
Metamorphosis of the Common Eel. 261
dispel in the most important points the great mystery which has
hitherto surrounded the reproduction and the development of the Com-
mon Eel (Anguilla vulgaris). When I reflect that this mystery has
occupied the attention of naturalists since the days of Aristotle, it
seems to me that a short extract of my work is perhaps not unworthy
to be presented to the Royal Society of London, leaving aside, how-
ever, for the present, the morphological part of my results.
The most salient fact discovered by me is that a fish, which
hitherto was known as Leptocephalus brevirostris, is the larva of the
Anguilla vulgaris.
Before giving the proofs of this conclusion I must premise that
the other Muraenoids undergo a similar metamorphosis. Thus, I
have been able to prove that the Leptocephalus stenops (Bellotti), for
the greatest part, and also the Leptocephalus morrisii and punctatus
belong to the cycle of evolution of Conger vulgaris ; that the Lepto-
cephalus hceclteli, yarrelli, bibroni, gegenbauri, kollikeri, and many
others imperfectly described by Facciola, and a part of the above-
named Leptocephalus stenops of Bellotti, belong to the cycle of evolu-
tion of Congromurcena mystax ; that the Leptocephalus tcenia, in-
ornatus, and diaphanus belong to that of Congromurcena balearica •
that under the name of Leptocephalus kefersteini are confounded the
larvae of various species of the genus Ophichthys ; that the Lepto-
cephalus longirostris and the Hyoprorus messanensis are the larvae of
Nettastoma melanurum, and that the Leptocephalus oxyrhynchus and
other new forms are larvae of Saurenchelys cancrivora, and that finally
a new little Leptocephalus is the larva of Muroena helena.
The form known as Tylurus belongs to Oxystoma, of which we
unfortunately know nothing more than a figure by Raffinesque. I
have not been able to find the Leptocephalus of Myrus vulgaris, of
which I have had only a single young individual, in which the trans-
formation was already far advanced. Neither have I found the Lepto-
cephalus of Chlopsis bicolorj a very rare form, which is related to
Murcena and to Murcenichthys. As the result of these observations,
the family of the Leptocephalidae has been definitely suppressed by
me ; the various forms of that family are, in fact, the normal larvae
of the various Mura3noids.
In regard to the greater part of the above-named species, the con-
trol has been threefold, namely : —
Firstly, anatomical. I have compared the various stages in all
their structures, and have made the due allowance for the changes
brought about by the metamorphosis at the close of larval life.
Secondly, natural. I have found in nature all the required transi-
tional stages.
Thirdly, experimental. I have followed, step by step, the meta-
morphosis in aquariums.
x 2
262 Prof. G. B. Grassi. The Reproduction and
Therefore, the hypothesis of Giinther that the Leptocephali are
abnormal larvas, incapable of further development, must be rejected.
All this is related by myself at length, with all historical details
which concern the question, in a large memoir which is about to
appear in the Journal edited by Professor Todaro.
Until now all these facts have been unknown because normally
they can only be observed in the abysses of the sea at a depth of at
least 500 metres. Fortunately, along a part of the coast of Sicily
strong currents occur, which must be ascribed to the tide, producing
very large displacements of the water in the narrow Strait of Mes-
sina. I shall give further details concerning these currents in my
large memoir. In consequence of the strong currents, sometimes — I
say sometimes, because there is no regularity, and one may have to
wait for a year without obtaining any material — not only many
deep-sea fishes, but also all stages of the development of the Murae-
noids are met with in the surface-water. To these currents we owe
all the captures of Murcena Jielena with ripe eggs, which is in accord-
ance with what I had already argued from other facts, namely, that
the reproduction of the Muraenoids takes place at great depths of the
sea.
Before I proceed to speak of the Common Eel, I must premise that
Dr. Kaffaele has described certain pelagic eggs as belonging to an
undetermined species, putting forward the suggestion that these
eggs belong to some Muraenoid. This matter has been investigated
by myself, and I have shown that the newly hatched larvae (called
" praa-larvae " by me) derived from these eggs have essentially the
character of Leptocephali.
The life history of the Muraonoids, leaving aside for the present
the Common Eel, is as follows : — Females can only mature in very
profound depths of the sea, that is to say, at least a depth of 500
metres. This fact I established by finding well-known deep-sea
fishes together with Leptocephali, ripe Muraenae, and quite ripe eels
{see below). The females of those species which do not live at this
depth must therefore migrate to it. The male, however, can mature
at a smaller depth, and therefore they migrate into the greater depth
when they are already mature. Fertilisation takes place at great
depths ; the eggs float in the water ; nevertheless they remain at a
great depth in the sea, and only exceptionally, for unknown reasons,
some of them mount to the surface.
From the egg issues rapidly a pras-larva, which becomes a larva
(Leptocephalus) with the anus and the urinary opening near the tip
of the tail. The larva then becomes a hemi-larva, the two aper-
tures just named moving their position towards the anterior part of
the body, which becomes thickened and nearly round. By further
-change the hemi-larva assumes the definitive or adult form. The
Metamorphosis of the Common Eel. 263
larva, as well as the hemi-larva, shows a length of body much
greater than that exhibited by the young Muraenoid of adult form
into which they are transformed. By keeping specimens in an aqua-
rium, I was able to establish a diminution of more than 4 cm. during
the metamorphosis. With regard to the greatest length which the
larva can attain in a given species, -and the amount of diminution
which accompanies metamorphosis, there are great individual varia-
tions.
The history of the Common Eel, to which I am now about to
refer, is very similar to that given above for the other Mursenoids.
The Common Eel (Anguilla vulgaris) undergoes a metamorphosis,
and before it assumes the definitive adult form it presents itself as
a Leptocephalus, which is known as Leptocephalus Irevirostris. This
Leptocephalus was discovered in the Strait of Messina many years
ago. A specimen was also captured by the " Challenger," and
another specimen was taken by the Zoological Station of Naples in
the Strait of Messina. This form is occasionally carried to the
surface by currents. By exception, in the month of March, in the
year 1895, we captured several thousands of them in one day, but
the best way to secure this Leptocephalus (and a very easy one) is to
open the intestine of the Orthagoriscus mola, a fish which is common
in the Strait of Messina, and in it one is certain to find a very
large number of specimens. It must be observed that Orthagoriscus
mola is a deep-sea fish. The specimens of Leptocephalus brevirostris
found in the intestine of Orthagoriscus are more or less altered by
digestion. Those specimens of Leptocephalus brevirostris which are
taken near the surface in the open sea are in a better state of preser-
vation, but, unfortunately, these also frequently have the epidermis
injured so that they cannot maintain their life in an aquarium for
more than a few days; they live long enough, however, to allow us
to observe that it is their habit to conceal themselves in the sand or
in the mud as the Common Eel (Anguilla) does. Here it is to be
noted that the various forms of Leptocephali have habits resembling
those of the Mursenoids to which they belong, i.e., they dig into the
sand or abstain from doing so according as the adult form has or has
not this habit.
I now pass on to the characters of Leptocephalus brevirostris. I give
them here in the same order as I shall use in my larger memoir. The
length varies from 77 — 60 mm., the same extent of variation as
observed in other Muraenotds. The caudal fin tends to assume the
form which it has in the Elver* or young Anguilla. It is to be noted
that in other Leptocephali the caudal fin also tends always to exhibit
the adult form. The lower jaw projects sometimes more than the
* The word " Elver " is used in this paper in its strict sense, viz., for the young
form of Anguilla vulgaris as taken when ascending rivers in vast numbers.
264 Prof. G. B. Grassi. The Reproduction and
upper jaw, as in Anguilla. The margin of the month is wide, as in
Angnilla. The tongue is free, as in Anguilla. On the other hand,
the youngest elvers which I have observed, have smaller eyes than
Leptocephalus brevirostris, and this need not surprise us since we know
that in other species of Mura3noids the diminution of the eyes occurs
during the metamorphosis. T,he nostrils are separated from one
another, the anterior tubes are relatively at a considerable distance
from the tip of the snout and from the rim of the mouth. They are
in a position in which they are observed in many other Leptocephali,
which are destined to transform themselves into adult forms having
the anterior nostrils in nearly the same position as in the Common Eel.
The posterior nostrils, on the contrary, are not tube-like, and are in
the same position as those occupied in the adult Anguilla. It is worth
remarking that in other Leptocephali also the posterior nostrils have
already assumed the adult position when the anterior ones are still
far removed from it. In L. brevirostris I find a larval dentition,
which resembles that of the other Leptocephali. In correspondence
with the small size of Leptocephalus brevirostris the number of larval
teeth is small. Researches fonnded, firstly, on the enumeration of
the myomeres ; secondly, upon the enumeration of the dorsal and
ventral arches of the vertebrae of the caudal extremity (hypnrals) ;
and, thirdly, upon the enumeration of the posterior spinal ganglia,
lead with great certainty to the conclusion that the Leptocephalus
brevirostris is the larva of a Muraenoid, the number of whose vertebrae
must lie between 112 and 117, most probably 114 or 115. Such a
Mursenoid is the Anguilla vulgaris. The Mura3noid indicated cannot
be any other of those occurring in the Mediterranean, because they
all have a number of vertebras higher than 124.* Counting the
myomeres in Leptocephalus brevirostris one finds generally only 105
complete, five others incomplete, and all the others in a state of
transparency and incomplete formation. These latter are fortunately
a,t the posterior extremity, where other criteria come to our assistance,
namely, the spinal ganglia and the vertebral arches. To show how I
arrive at the number of vertebrae which must be possessed by the
adult individual, corresponding to a given Leptocephalus brevirostris,
I quote the following example : — I assume that three vertebras
develop themselves in correspondence to the first four incomplete
myomeres, and that 105 must develop themselves in relation to the
105 complete myomeres, that is to say, between the fourth and fifth
myomeres, between the fifth and sixth, and so on, until we reach the
105th vertebra, lying between the 104th and 105th myomeres. I
* Muroenesox savanna is said to have 109 vertebrae, but it is doubtful whether it
really occurs in the Mediterranean. The position of its nostrils and the number
of its branchiostegal rays render its association with Leptocephalns brevirostris
impossible.
Y
Metamorphosis of the Common Eel. 265
further conclude that seven other vertebras are developed at the
caudal extremity, as indicated by the number of vertebral arches and
the spinal ganglia in that region. We count, therefore, in all 115
vertebrae, and this is the number which can be easily seen in many
specimens of Anguilla vulgaris.
Here I must particularly insist that I have .ascertained in an
absolute manner that during the metamorphosis of the Mureenoids,
the number neither of the myomeres nor of the vertebral arches, nor
of the spinal ganglia is subjected to any change. The hypurals of
Leptocephalus brevirostris are precisely 'the same as in the elver of
Anguilla vulgaris. The last hypural which is fused with the urostyle
may present itself as a single piece, or may be more or less cleft.
These are variations which are met with also in the elver. Just as
in the elver, the last hypural but one is always extensively cleft, or,
if the expression is preferred, doubled. To the last hypural corre-
spond five rays, whilst four correspond to the last but one, and one to
the last but two, the whole structure being identical with that found
in the elvers of Anguilla vulgaris. Of these ten rays, the eighth,
seventh, and sixth are bifid, both in Leptocephalus brevirostris and in
the elvers of Anguilla vulgaris. In the pectoral fin of Leptocephalus
brevirostris the definitive rays can be observed, and these are of the
same number as in the elvers of Anguilla vulgaris. Leptocephalus
brevirostris is transparent, and has colourless blood. The red cor-
puscles are wanting, but there are present so-called " blood-plates "
(" Blutplattchen " in German) similar to those of the inferior
vertebrates. The bile is also colourless. This fact is observed in all
the other Leptocephali. Leptocephalus brevirostris is, however, the
only one which is free from all pigmentation. Correspondingly, the
Common Eel is the only species of Muraenoid which at the close of
metamorphosis is devoid of all trace of larval pigmentation. It was
this observation which first led us to the discovery of the relations
between Leptocephalus brevirostris and Anguilla vulgaris.
In making transverse sections of Leptocephalus brevirostris, I found
other characters which confirm the relation between it and the Com-
mon Eel ; for instance, the branchiostegal rays are ten to eleven in
number, as is also observed in the elvers of Anguilla vulgaris. In the
Common Eel the well-known lateral branch of the fifth pair of the
cranial nerves exists. It is also found in Leptocephalus brevirostris.
This lateral branch could not be found by Dr. Calandruccio in the
other common Murasnoids of Sicily, and is wanting also in the other
Leptocephali.
The mucous-canal-system (sensory canals) in the head are already
developed, partially, in Leptocephalus brevirostris, and are incom-
pletely developed in the elver. As in the elver, so in Leptocephalus
brevirostris, the pyloric cceca are wanting. The blind extremity of
2(i6 Prof. G. B. Grassi. The Reproduction and
the stomach and the incompletely developed swim-bladder, which is
as yet free from contained gas, are present both in Leptocephalus
brevirostris and in the elver of Anguilla vulgaris. The pronephros is
in active function as in the other Leptocephali. The Malpighian
glomerules of the kidney (mesonephros) are lobed as in the eel, and
their number corresponds with that observed in the Helmichthys
stage, of which I will speak further on. The genital gland, not yet
sexually differentiated, is almost identical with that of the same
stage. In short, it may be said that the whole organisation of
Leptocephalus brevirostris corresponds with the organisation of the
Common Eel, if we make allowance for those changes, which are
observed in the matamorphosis of the other species of Mureenoids,
such as reduction of the pancreas and of the liver, disappearance of
the proto-skeleton, complication of the musculature, increase in size
of the cerebellum, loss of the larval teeth, development of the defini-
tive teeth, &c.
From the description of these Leptocephali I must pass on, briefly,
to speak of the stages nearer to the condition ol the elver. I am,
however, obliged to leave a break in the series, which, however little
its significance, yet certainly will make some impression on the minds
of those who do not realise with what caution I have formed my con-
clusions. I must confess that since I have learnt how difficult it is
to procure an entire series of the development of a Mura3noid, I
am more astonished at being able to recognise a single stage in the-
development of a given species than at not finding the whole series.
I in nst point out that the break in my series of the development of
Anguilla vulgaris would have been much smaller if I could have
persuaded myself to kill and preserve one of the hemi-larvae which I
happened to meet with at the end of the year 1892. They were
really transitional stages between Leptocephalus brevirostris and that
stage which I shall describe further on. I published this fact in a
preliminary note in the month of May, 1893. They were transparent
with almost colourless blood, without any trace of pigmentation,
except at the eyes, and had lost all the larval teeth, whilst they
possessed already very few and very minute teeth of the definitive
series. The body was thickened, and already showed the cylindrical
form. They measured little less than 8 cm. In short, they were
Leptocephalus brevirostris on the way to transformation into Anguilla
vulgaris. As a matter of history they actually did transform them-
selves in my aquarium with the usual diminution in their dimen-
sions, and subsequently proceeded to increase in bulk.* The meta-
morphosis took place as usual without the animal taking in any
* The fact that I actually hare obtained in an aquarium the transformation of
L. brevirostris into Anguilla vulgaris is of prime importance. The time occupied
was one month.
Metamorphosis of the Common Eel. 267
nourishment whatever. The resumption of growth was accompanied
by a resumption of feeding. Unfortunately, I had no other indi-
viduals of this stage.
The stage which I now pass on to describe can be obtained during
the winter in the sea. I have never found them at the mouths of
rivers. The length varies from 54 to 73 mm. Most individuals
measured about 65 mm. The body is relatively longer than in the
elver. It is also relatively deeper, as in Leptocephalus. We are
reminded of Leptocephalus also by the pigment of the eye, the
vitreous transparency of the body, the swim-bladder being indis-
tinguishable in the living animal, and the absence of all larval pig-
mentation. The blood is slightly coloured, and the bile is already
green. Slight pigmentation can be seen along the central nervous
system, and at the middle part of the caudal fin. This commence-
ment of the definitive or adult pigmentation in the regions named
before it occurs in any other part is also seen in other Muraenoids.
The definitive teeth are very minute, and few in number. The
intestine contains no food. After what I had observed in the other
Mursenoids, the simple observation of the barely indicated teeth,
and of the absence of aliment in the gut, would have been sufficient
to convince me that the stage now under notice must be preceded by
a Leptocephalus phase. Indeed, if we did not admit such a preceding
history, we could not understand how this little fish could have
attained such a size without acquiring well developed teeth, and with-
out nourishing itself.
In conclusion, no one would hesitate, even not knowing Lepto-
cephalus brevirostris, to refer the stage now under discussion to a
Mureeiioid about to complete its Leptocephalus metamorphosis, were
it not for the fact that there has been so much question concerning
the reproduction of the Common Eel, and that so many capable
observers have failed in dealing with it, that every new observation
is received with scepticism. The stage of which I am now speaking,
in the hands of a pure systematist, would probably be described as a
Helmicthys, a genus established for certain forms of Leptocephali far
advanced in transformation.
The next forms to which I have to refer are captured in the course
of migration from the sea into fresh water. When kept in an
aquarium they assume the characters of the elver, diminishing more
or less in volume, and without nourishing themselves. The elvers
of the Common Eel can present themselves in stages differing
little from that last described, as well as in a form which has
already developed the full pigmentation of the adult. Even those
which most resemble the preceding stage always have a character
which distinguishes them easily, namely, the presence of definitive
pigment, more or less superficially placed on the head, and not to be
268 Prof. G. B. Grassi. The Reproduction and
confounded with the pigment round the posterior extremity of the
brain, which latter is already present in the preceding stage. In
specimens taken at the mouths of rivers this more or less superficial
pigment was, so far as I could ascertain, always present.
As the pigmentation develops itself, the little eel gradually under-
goes a diminution in all its dimensions. It results from my measure-
ments, that the fully pigmented elver has an average length of
61 mm., while for the more or less colourless elver the average length
is 67 mm. I found pigmented elvers which were reduced in length to
51 mm., a size which I never observed in those elvers in which the
development of pigment had not taken place.
The facts which I have stated demonstrate that the eel goes
through a metamorphosis, and that Leptocephalus brevirostris is its
larva. Some further considerations remain to be given, although I
believe that zoologists will not consider the question still an open
one after the record of facts given above — facts, which anyone may
verify by examining the material which is preserved in my hands.
Many to whom I have related my discovery of the history of the
Common Eel have objected that eels are found almost everywhere,
whilst Leptocephalus brevirostris is limited to Messina. In reply, I
must say that, first of all, it is not true that Leptocephalus brevirostris
is limited to Messina ; secondly, that at Messina there are special
currents, which tear up the deep-sea bottom which everywhere else is
inaccessible ; thirdly, although it is true that on the coasts of many
countries where Anguilla vulgaris is found, no one has ever seen a
Leptocephalus brevirostris ; it is also true that in no country, not even
in those where eels are abundant, has anyone ever seen an eel of less
than 5 cm. in length. Since it has to be admitted that no one knows
the eel before it arrives at the length of 5 cm., there is no greater
difficulty in supposing that during this unknown period the eel
passes through a Leptocephalus stage than in supposing that it does
not do so. The critical study of the literature of this subject, and a
great many continued observations, have occupied me for many
years, and have been undertaken just in those places where young
eels are to be found. They enable me, from my own studies, to
affirm with assurance that young eels with the definitive adult form
do not exist of less than 5 cm. in length.
From the study of the memoir of Raffaele on pelagic eggs, I have
come to the conclusion that the eggs of his undetermined species
No. 10, having a diameter of 2'7 mm. and differing from all the
others in the absence of oil globules,* must belong to the Anguilla
* Kenewed researches have convinced me that this egg is that of Anguilla
vulgaris. There is, however, another egg belonging to an undetermined Muraenoid
which is devoid of oil-drops, and can easily be confused with the true eggs of
Anguilla.
Metamorphosis of the Common Eel. 269
vulyaris, because from them Dr. Raffaele obtained prse-larvse which
had only forty-four abdominal myomeres. T endeavoured for two
years in vain to study these eggs at the Zoological Station of Naples.
I found only a few of them, and these died prematurely.
In another point my researches have yielded a very interesting
result. As a result of the observations of Petersen, we know now
that the Common Eel develops a bridal coloration or " mating
habit," which is chiefly characterised by the silver pigment without
trace of yellow, and by the more or less black colour of the pectoral
tin, and finally by the large eyes. Petersen inferred that this was
the bridal coloration from the circumstance that the individuals
exhibiting it had the genital organs largely developed, had ceased to
take nourishment, and were migrating to the sea. Here Petersen's
observations cease and mine begin. The same currents at Messina
which bring us the Leptocephali bring us also many specimens of
the Common Eel, all of which exhibit the silver coloration. Not a
tew of them present the characters described by Petersen in an
exaggerated condition, that is to say, the eyes are larger and nearly
round instead of elliptical, whilst the pectoral fins are of an intense
black. It is worth noting that in a certain number of them the
anterior margin of the gill slit is intensely black, a character which I
have never observed in eels which had not yet migrated to the sea,
and which is wanting in the figures and in the originals sent to me by
Petersen himself. Undoubtedly the most important of these changes
is that of the increase of the diameter of the eye, because it finds its
physiological explanation in the circumstance that the eel matures in
the depths of the sea. That, as a matter of fact, eels dredged from
the bottom of the sea have larger eyes than one ever finds in fresh-
water eels, I have proved by many comparative measurements, made
between eels dredged from the sea bottom and others which had not
yet passed into the deep waters of the sea. Thus, for instance, in a
male eel taken from the Messina currents and having a total length
of 34 J cm., the eye had a diameter, both vertical and transversal, of
9 mm., and in another eel of 33 J cm., the same measurement was
recorded. In a female eel, derived from the same source and
purchased in the market, whose length was 48 \ cm., the vertical
diameter of the eye was 10 mm., and the transversal diameter rather
more than 10 mm. These are not the greatest dimensions which I
observed, and I conclude from these facts that the bridal habit
described by Petersen was not quite completed in his specimens, and
that it becomes so only in the sea and at a great depth. In relation
'to these observations of mine stands the fact that the genital organs
in the eel taken in the Messina currents are sometimes more
developed than in eels which have not yet entered the deep water.
Thus it has happened that male individuals have occurred showing
270 The Reproduction and Metamorphosis of the Common Eel.
in the testes here and there knots of spermatozoa. These spermato-
zoa are similar to those of the Conger vulgaris, and must be con-
sidered as ripe. As is well known, so advanced a stage of sexual
maturity has never before been observed in the Common Eel. This
appears to be due to the fact that the males hitherto examined had
not yet migrated into the deep water of the sea.
Eels with big eyes taken from the depths of the sea were, before
the above facts were known, described as a distinct species under
the name of Anguilla bibroni (Kaup) and of Anguilla kieneri (Kaup),
not to be confounded with Anguilla kieneri (Giinther), which is a
synonym of Lycodes 'kieneri.
In certain cloacae of ancient Rome which to-day are disused and
contain pure water, remarkable eels are found of a length of from
20 — 30 cm. of a grey colour, without trace of yellow, of male and
female sex, with enormous eyes and with more or less rudimentary
genital organs. They are individuals which, confined in a place
without light, have acquired prematurely one of the characters of
the bridal habit without a corresponding development of the genital
organs. These individuals are probably incapable of ulterior de-
velopment, as the condition of their genital organs seems to demon-
strate.
Under the name Anguilla kieneri (Kaup) there have probably been
included some individuals which had acquired big eyes under con-
ditions similar to those described for the eels of these Roman cloacae.
From these and similar observations it clearly results that all the
European eels must be included under a single species, and this is an
important fact from another point of view, namely, that it destroys
an objection which might be raised against my conclusion with
regard to the development of Anguilla vulgaris from Leptocephalus
brevirostris, namely, the objection that Leptocephalus brevirostris
belongs not to Anguilla vulgaris, but to Anguilla kieneri, or to
Anguilla bibroni.
To sum up, Anguilla vulgaris, the Common Eel, matures in th&
depths of the sea, where it acquires larger eyes than are ever observed
in individuals which have not yet migrated to deep water, with the
exception of the eels of the Roman cloacae. The abysses of the sea
are the spawning places of the Common Eel : its eggs float in the sea
water. In developing from the egg, it undergoes a metamorphosis,
that is to say, passes through a larval form denominated Leptoce-
phalus brevirostris. What length of time this development requires
is very difficult to establish. So far we have only the following
data : — First, Anguilla vulgaris migrates to the sea from the month
of October to the month of January ; second, the currents, such as.
those of Messina, throw up, from the abysses of the sea, specimens
which, from the commencement of November to the end of July,.
Eclipse of the Sim, 1896. — Novaya Zemlya Observations. 271
tire observed to be more advanced in development than at otber times,
but not yet arrived at total maturity ; third, eggs, which according
to every probability belong to the Common Eel, are found in the sea
from the month of August to that of January inclusive ; fourth,
the Leptocephalus brevirostris abounds from February to September.
As to the other months, we are in some uncertainty, because during
them our only natural fisherman, the Orthagoriscus mola, appears
very rarely; fifth, I am inclined to believe that the elvers ascending
our rivers are already one year old, and I have observed that in
an aquarium specimens of L. brevirostris can transform themselves
into young elvers in one month's time.
" Total Eclipse of the Sun, 1896.— The Novaya Zemlya
Observations." By Sir GEORGE BADEN-POWELL, K.C.M.G.,
M.P. Communicated by J. NORMAN LOCKYER, C.B., F.R.S.
Received November 19, — Read November 19, 1896.
(Abstract.)
The author gives an account of the circumstances under which it
became desirable to fit out an expedition to observe the eclipse in
Novaya Zemlya, and the arrangements made to convey it by his
yacht " Otaria."
Details are given of the observing station, the erection of the dif-
ferent instruments, and the scheme of work.
The valuable spectroseopic results obtained are still under process
of being worked out ; but the coronagraph results are reported in
detail, and copies of the chief photographs are appended. The
meteorological and other conditions during the eclipse are duly
recorded.
^Preliminary Report on the Results obtained with the Pris-
matic Camera during the Eclipse of 1896." By J. NORMAN
LOCKYER, C.B., F.R.S. Received November 17, — Read
November 19, 1896.
(Abstract.)
The author first states the circumstances under which Sir George
Baden-Powell, K.C.M.G,, M.P., with great public spirit conveyed an
eclipse party to Novaya Zemlya in his yacht " Otaria," to which
party was attached Mr. Shackleton, one of the computers employed
by the Solar Physics Committee.
The prismatic camera employed, loaned from the Solar Physics
272 List of Officers and Council nominated for Election.
Observatory, was carefully adjusted before leaving England, and a
programme of exposures was drawn up based upon the experience of
]893. As the station occupied lay at some distance from the central
line, this programme was reduced by Mr. Shackleton.
Two of the photographs obtained are reproduced for the informa-
tion of other workers, as some time must elapse before the discussion
of all the results can be completed. This discussion and Mr. Shackle-
ton's report on the local arrangements and details of work, are
promised in a subsequent communication.
The lines photographed in the " flash " at the commencement of
totality — happily caught by Mr. Shackleton — the wave-lengths of
which lines have been measured by Dr. W. J. S. Lockyer, show
interesting variations from those photographed by Mr. Fowler in the
cusp during the eclipse of 1893. '
With the exception of the lines visible in the spectra of hydrogen
and helium, and the longest lines of many of the metallic elements,
considerable differences of intensity from the lines of Fraunhofer
are noticeable.
The coronal rings have been again photographed, and the results of
1893 have been confirmed.
November 26, 1896.
Sir JOSEPH LISTER, Bart., President, in the Chair.
Dr. George Murray and Professor Karl Pearson were admitted into
the Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
In pursuance of the Statutes, notice of the ensuing Anniversary
Meeting was given from the Chair, and the list of Officers and Council"
nominated for election was read as follows : —
President. — Sir Joseph Lister, Bart., F.R.C.S., D.C.L.
Treasurer.— Sir John Evans, K.C.B., D.C.L., LL.D.
Secretaries. —
/ Professor Michael Foster, M.A., M.D.
I Professor Arthur William Biicker, M.A., D.Sc.
Foreign Secretary. — Edward Frankland, D.C.L., LL.D.
Other Members of the Council. — Professor William Grylls Adamsr
M.A.; Professor Thomas Clifford Allbutt, M.D. ; Professor Robert
Mathematical Contributions to the Theory of Evolution. 27;}
Bellamy Clifton, M.A. ; William Turner Thiselton Dyer, C.M.G. ;
Professor James Alfred Ewiiig, M.A. ; Lazarus Fletcher, M.A. ; Walter
Holbrook Gaskell, M.D. ; Professor Alfred George Greenhill, M.A •
William Huggins, D.C.L. ; Professor Charles Lapworth, LL.D. \
Major Percy Alexander MacMahon, R.A.; Professor Raphael Meldola',
F.C.S.; Professor William Ramsay, Ph.D. ; The Lord Walsinglmm'
M.A. ; Professor Walter Frank Raphael Weldon, M.A. ; Admiral
William James Lloyd Wharton, C.B.
The following Papers were read: —
I. "Mathematical Contributions to the Theory of Evolution. On
• Telegony in Man, &c." By KARL PEARSON, F.R.S., University
College, with the assistance of Miss ALICE LEE, Bedford
College, London.
II. " On the Magnetic Permeability of Liquid Oxygen and Liquid
Air." By J. A. FLEMING, M.A., D.Sc., Professor of Electrical
Engineering in University College, London, and JAMES DEWAK,
LL.D., F.R.S., Fullerian Professor of Chemistry in the Royal
Institution.
" Mathematical Contributions to the Theory of Evolution. On
Telegony in Man, &c." By KARL PEARSON, F.R.S., Uni-
versity College, with the assistance of Miss ALICE LEE,
Bedford College, London. Received August 27, — Read
November 26, 1896.
(1) The term telegony has been used to cover cases in which a
female A, after mating with a male B, bears to a male C offspring
having some resemblance to or some peculiar characteristic of A's
first mate B. The instances of telegony usually cited are (i) cases
of thoroughbred bitches when covered by a thoroughbred dogt
reverting in their litter to half-breds, when they have been previously
crossed by dogs of other races. Whether absolutely unimpeachable
instances of this can be produced is, perhaps, open to question, but
the strong opinion on the subject among dog-fanciers is at least
remarkable; (ii) the case of the quagga noted by Darwin (see
* Origin of Species,' 4th edition, p. 193), and still more recently
(iii) a noteworthy case of telegony in man cited in the 'British
[edical Journal' (see No. 1834, February 22, 1896, p. 462).
In this latter case a very rare male malformation, which occurred,
in the male B, was found in the son of his widow A, by a second
msband C. Here, as in the other cases cited, a question may always-
raised as to the possibly unobserved or unknown occurrence of the
274 Prof. Karl Pearson.
characteristic in the ancestry of either A or C, or again as to the
chance of the characteristic arising as a congenital sport, quite inde-
pendently of any heredity. It seems unlikely that the observation
of rare and isolated cases of asserted telegony will lead to any very
satisfactory conclusions, although a well-directed series of experi-
ments might undoubtedly do so. On the other hand, it is not impos-
sible than an extensive and careful system of family measurements
might bring to light something of the nature of a telegenic influence
in mankind.
If such a telegenic influence really exists, it may be supposed to
act in at least two and, very possibly, more ways.
(a) There may be in rare and isolated cases some remarkable
change produced in the female by mating with a particular male, or
some remarkable retention of the male element.
(6) There may be a gradually increasing approximation of the
female to the male as cohabitation is continued, or as the female
bears more and more offspring to the male.
It is extremely unlikely that any system of family measurements
would suffice to bring out evidence bearing on (a). On the other
hand, a closer correlation between younger children and the father,
and a lesser correlation between younger children and the mother, as
compared with the correlation between elder children and their
parents might, perhaps, indicate a steady influence like (&) at v\rork
in mankind. Shortly, such measurements might suffice to answer
the question as to whether younger children take more after their
father and less after their mother than elder children. Without
hazarding any physiological explanation as to the mode in which
telegonic influence can or does take place, we may still hope to get, at
any rate, negative evidence as to a possible steady telegonic influence
by an investigation of suitable family measurements.
(2) Unfortunately, the collection of family data is by no means
an easy task, and to procure those head-measurements, which, I
think, would be most satisfactory for the problem of heredity, would
require a large staff of ready assistants, and could only be undertaken
on the necessary scale by the action of some scientific society or
public body. The data concerning 800 to 900 families which have been
recently collected for me deal only with stature, span, and arm-length,
which are measurable with more or less accuracy by the untrained
observer, and are only suitable for more or less rough appreciations of
hereditary influence. The numbers in each family measured were
strictly limited, in order to remove the influence of reproductive
selection from the determination of the correlation between parents
and children, and the result of this limitation has been that compara-
tively few couples of elder and younger brothers, and of elder and
younger sisters are available. They were, indeed, collected in the
Mathematical Contributions to the Theory of Evolution. 275
first place with a view to the problem of heredity in the direct line,
and with no thought of their throwing any light on the problem of
telegony. That steady telegonic influence might be deduced from
such family data has only recently occurred to me, and I should now
hesitate to publish any conclusions on this subject, based on some-
what mixed and sparse returns, did I not consider that it may be a
long time before more extensive returns are available, and that the
publication of this method of dealing with telegony may induce others
to undertake the collection of a wider range of material.
My own 800 family data cards did not provide a sufficiently large
number of either brother- brother or sister-sister couples to give a
strong hope of a difference between the correlation coefficients
sufficiently large as compared with its probable error to base any
legitimate conclusion upon. I, therefore, again borrowed from Mr.
Galton his 200 family data returns, and from these 1,000 families
was able to select 385 brother-brother pairs and 450 sister-sister
pairs. In these statistics each individual is only included in one
pair, and the difference in age between the elder and younger mem-
bers of each pair differs very widely from pair to pair. In some cases
there may be several years between the ages and several intervening
children ; in others the members of the pair may be successive
children following each other in successive years. In each case all
we can say is, that if there be a steady telegonic influence, the rela-
tion of the elder member to the parent will weigh down the same
scale, and in the final result we ought to find a distinctly greater or
less correlation, as the case may be. I think a more serious objection
to the data than the variation in the number of years between
fraternal pairs is the mixture I have made of data collected at
different periods and in somewhat different manners. My own data
are drawn, I think, from a wider class of the community than Mr.
Galton's. They are not exclusive of his class, but, I think, cover his
class, and go somewhat further down in the social scale. They suffice
to show that the means and variations change considerably from one
social stratum to another, and what is still more important that the
Galton-Functions or coefficients of correlation for heredity are far
from being constant even within the same race, as we pass from one
rank of life to a second. Thus, my means for stature in the case of
both fathers and mothers are upwards of ^ in. less than Mr. Galton's,
but my means agree fairly well with his results in the case of both
sons and daughters. There are also good agreements and somewhat
puzzling disagreements not only in the variations, but, above all, in
the coefficients of correlation for heredity. I reserve for the present
the full discussion of my heredity data, but I wish it to be quite
understood that my conclusions in this paper are based, not upon the
best possible data, e.g., measurements made on one class of the com-
VOL. LX. Y
276
Prof. Karl Pearson.
munity under one system, but upon all the data which, for some time
to come, appear likely to be available. These data are neither quan-
titatively nor qualitatively ideal, but, on the other hand, they must
be given a reasonable amount of weight in considering whether, at
any rate in the case of one organ — stature, — any steady telegenic
influence can be traced in man.
The reduction from the family measurement-cards, the formation
of the eight correlation tables, and the calculation of both variation
and correlation coefficients have been undertaken by Miss Alice Lee
of Bedford College, — a task requiring much labour and persistency.
I have independently verified, and in some minor points corrected
her calculations, as well as added the probable errors of the con-
stants determined.
(3) The following are the means and standard-deviations with
their probable errors for the various groups.
Table I. — Stature of Families in Inches.
Class.
Number.
Mean.
Standard
deviation.
Fathers of sons . . •
385
68 -5740 ±0-0878
2 -5554 ±0-0621
Elder sons . . . . . .
69'1494±0'0913
2 -6550 ±0-0645
69 -1948 ±0-0933
2 -7128 ±0-0659
63 3078 ±0-0854
2 '4848 ±0-0604
Fathers of daughters . • • . .
450
68 -3344 ±0-0878
2*7605 ±0-0621
63 -9244 ±0-0823
2'5878±0-0582
64 -2200 ±0-0794
2 -4985 ±0-0562
Alothers of daughters . .
63 -1794 ±0-0758
2 -3827 ±0-0536
All the quantities have here been calculated precisely as in my
third memoir on the mathematical theory of evolution (see ' Phil.
Trans./ A, vol. 187, pp. 270 — 271). In this case, however, no child is
included twice as a child, and parents are not weighted with their
offspring. Thus reproductive selection is not allowed to influence the
results.
It will be seen that the probable errors of the means and standard
deviations are, as in the former paper, too large to allow of
absolutely definite conclusions when those conclusions are not sup-
ported by a continuous change of values, or directly verified by the
numbers of the earlier memoir. But one or two such conclusions
may be drawn, and I will note them before passing to correlation.
(i) The law of sexual interchange referred to in my former paper
(p. 274) is confirmed with greater uniformity. Fathers of sons are
sensibly less variable than fathers of daughters, and mothers of
daughters are sensibly less variable than mothers of sons. In other
Mathematical Contributions to the Theory of Evolution. 277
words, to judge from stature, the exceptional parent tends to have
offspring of the opposite sex.
(ii) Younger sons are taller and more variable than elder sons,
and elder sons are taller and more variable than fathers.
This conclusion, although less markedly, appears in the results on
pp. 270 and 281, of my former paper. It might be accounted
for by :
(a) A secular change going on in the stature of the population,
and even noticeable in the difference between the stature of
younger and elder sons.
(6) A further growth of sons, and an ultimate shrinkage, which
will leave them at the age of their fathers with the same
mean height and variation.
(c) Conditions of nurture on the average less favourable, and on
the whole less varied in the case of elder than in that of
younger children.*
(d) Natural selection. The difference between younger and elder
sons and between elder sons and fathers represents the
selective death rate in man due to causes correlated with
stature in the years between youth and manhood, and man-
hood and age. The difference is thus to be accounted for
by a periodic and not a secular change.
Possibly (a), (6), (c), and (d), may all contribute to the observed'
results. It cannot be denied that (d) has a special fascination of its
own for the student of evolution, but prolonged study of the laws of
growth must precede the assertion that we have here, or in any
similar case, real evidence of an actual case of natural selection.
(iii) Younger daughters are taller than elder daughters and elder
daughters than mothers.
This is in complete agreement with the result for fathers and sons.
Further :
Daughters, as a class are far more variable than mothers, but
while in the earlier memoir younger daughters were sensibly more
variable than elder daughters — and thus exactly corresponded with
sons — elder daughters are in this case more variable than younger. I
have been unable to find any slip in the tables or calculations, which
might account for this divergence. It exceeds considerably the
probable error of the observations, and is not in accordance with
the general law connecting the variation of parent and offspring evi-
denced for both sexes in the earlier, and for sons in the present
memoir — e.g., the variation — whether it be due to growth- change,
* Mr. Francis Galton suggests this as a possible cause. It has, I think, to be
taken in conjunction with a greater amount of parental experiment, not only in the
birth, but in the nurture of the elder children.
y 2
278
Prof. Karl Pearson.
or to selective death-rate, or to secular evolution — diminishes with
age.
(4) The following are the coefficients of correlation (r) and the
coefficients of regression (B) for parents and sons :
Table II. — Inheritance of Stature by Sons.
Father and elder sons
Father and younger sons ....
Mother and elder sons
Mother and younger sons . . .
r.
0-4120 ±0-0264
0-4170 ±0-0262
0'4094± 0-0265
0-4111 ±0-0264
R.
0 -4281
0-4427
0 -4374
0 -4488
If we measure, as seems reasonable, the hereditary influence of
parentage by the magnitude of the coefficient of correlation between
parent and offspring, then several important conclusions may be
drawn from this table.
(i) There is no sensible difference between the influences of the
father on younger and on elder sons, and no sensible difference
between the influences of the mother on younger and on elder sons.
If we pay attention to such slight differences as exist, there would
appear, not to be an increase of paternal and a decrease of maternal
influence on younger children, but an extremely slight increase of
both. In other words, so far as stature in sons is concerned, judged
by correlation : No steady telegonic influence exists.
(ii) There is a very slight prepotency of the father over the
mother in the case of both younger and elder sons ; a prepotency
which will be slightly magnified when account is taken of the abso-
lute stature of the two parents.
But the great prepotency of paternal inheritance noticed in the
former memoir is not confirmed. The co-efficients of maternal in-
heritance have been increased by more than 30 per cent, (from O293
to 0'410), while those of paternal inheritance (0'396 as compared
with 0*414) have remained almost stationary. This result seems to
show the want of constancy of the Galton's functions for heredity
within the same race. An explanation on the ground that the
present statistics embrace a wider range of the community than the
earlier, and possibly a more closely correlated class,* fails, at any
rate in part, owing to the sensible constancy of the paternal correla-
tion. The main difference of course between the present and the
former statistics is the exclusion of the influence of reproductive
* I have pointed out (loc. cit., p. 284) that working and lower middle class
families appear to be more closely correlated than those of the upper middle class.
Mathematical Contributions to the Theory of Evolution. 279
selection, but why should this be expected to influence only the
mother ? The father of many children remains equally influential,
but the mother's relation is weakened when we give weight to the
quantity not the relative ages of her children. This is not a steady
telegonic influence, but a correlation between fertility and heredi-
tary influence in mothers, which if it could be verified by further
observation, would undoubtedly be of high significance. I would
accordingly suggest as a possible law of heredity, deserving careful
investigation, that : Hereditary influence in the female varies inversely
as fertility.
In my paper on " Reproductive Selection," (' Roy. Soc. Proc.,' vol.
59, p. 301), I have pointed out the important evolutionary results
which flow from a correlation between fertility and any inheritable
characteristic. If a law of the above character should be established
after further investigation, it is conceivable that it may act as an
automatic check on the extreme effects of reproductive selection.
(iii) The above results give us for practicable purposes a quite
sufficiently close value of the correlation between parents and sons,
when the influence of reproductive selection is excluded. Judging
from stature the correlation between sons and parents is very closely
given by
0-41 ±0-03.
The J, adopted by Mr. Galton, may, I think, safely be increased by
25 per cent., and further, the assumption that collateral heredity is
twice as strong as direct heredity must, I hold, be finally discarded,
for no determination of the former has given such a high value
as 0-82.
(5) Hitherto we have regarded only the coefficients of correlation,
and considered them to measure the strength of the hereditary in-
fluence, but it must be remembered that the means of elder and
younger sons are not the same, and that there is another way of
looking at the problem. We may ask : Do younger or elder sons
differ most from the stature of their father, and is the order altered
in the case of the mother ?
If we neglect the influence of sexual selection (see " Contributions to
Math. Theory of Evolution," 111, pp. 287 — 8) we have, if hf and hm
be deviations of father and mother from their means, and M, and
My be mean heights of corresponding fraternities of elder and younger
sons in inches :
M, = 69-1494 + 0-4281fc/+0-4374/i,B.
My = 691948 + 0-4427 V+0-4488fc».
Now the ratio of the mean heights of parents is 68'5740 : 63'3078 =
280 Prof. Karl Pearson.
1-0832,* while the ratios of 0*4374 to 0-4281 and 0*4488 to 0*4427,
are only T0219 and 1*0139 respectively, thus there is still a slight
prepotency of paternal influence on stature to be recorded. (See
§ (4) (ii).)
Confining our attention to the differences in stature for fathers and
sons corresponding to all mothers whatsoever, we have, if Def be the
difference in stature between father and corresponding fraternity of
elder sons, D^ between father and fraternity of younger sons :
Def= 0-5754-0-5719^.
Dyf= 0-6208- 0-5573 hf.
Hence the difference betwen the father and fraternity of younger
sons will be greater than the difference between the father and the
corresponding fraternity of elder sons unless the father be 3'110
inches less, or 1*059 more than the average. But 3*11 is about 1*2
and 1*059 about 0*415 times the standard deviation of the stature of
fathers, or, fraternities of younger sons are nearer in stature to their
father than fraternities of elder sons in about 46 per cent, of cases.
Similarly if Dgnt, ~Dym represent the differences of stature of mothers
and fraternities of elder and younger sons respectively, we have in
inches
Dem = 5*8416- 0-5626/4.
-Dyrn = 5-8870-0-5512AOT.
Thus fraternities of younger sons are always more divergent than
fraternities of elder sons from the stature of their mothers, unless the
mother be 3*982 inches less, or 10*53 inches more than the average.
These are 1'6 and 4*24 times the standard deviation in stature of
mothers ; or, only in about 5*5 per cent, of cases are fraternities of
younger sons nearer in stature to their mothers than elder sons.
Now, it is difficult to read into these results any evidence for a
steady telegenic influence. It is true that the case of younger sons
being more like their parents than elder sons occurs in eight times as
many cases with the father as with the mother, but the broad fact
remains that in more than half the cases, judged by difference of
stature, the elder son is more like the father than the younger son.
In fact, examined in this way by difference of stature — not an un-
. natural manner of first approaching the problem — the true closeness
of parent and offspring appears to be quite obscured by some secular,
or, at any rate, periodic (see § 3) evolution in stature between
successive generations — an evolution which even makes itself felt in
the interval between younger and elder sons.
* 13/12 = 1*0833; thus these returns again confirm Mr. Galton's selection of
this fraction for the sexual ratio for stature.
Mathematical Contributions to the Theory of Evolution. 281
(6) Turning to the results for daughters, we have the following
table for the coefficients of correlation and regression : —
Table III. — Inheritance of Stature by Daughters.
Fathers and elder daughters
Fathers and younger daughters
Mothers and elder daughters
Mothers and younger daughters . . .
0-4829 ±0-0220
0-4376 ±0-0236
0-3953 ±0'C250
0-4542 ±0-0230
E.
0 -4528
0 -396L
0 -4293
0 -4763
These results, more numerous than those for sons, are, for reasons
which I am unable to explain, much more divergent. We may note
the following points : —
(i) There is a sensible difference between the coefficients of corre-
lation for either parents with younger and elder daughters. Thus,
the difference of the coefficients for fathers with elder and younger
daughters is 0*0453, and the probable error of this only 0*032 ; while
for mothers the corresponding difference is 0*0589, and the probable
error of the difference only O0328. The difference, however, is
in the opposite sense. We are thus face to face with an increasing
maternal and a decreasing paternal influence on the stature of
daughters. In other words, our statistics are entirely opposed to any
steady telegonic influence on the sfcature of daughters. If such a
thing were conceivable, we should be confronted with the case of the
mother influencing the father, the reverse of telegony.
(ii) The mean correlation of fathers and daughters is very slightly
higher than that of mothers and daughters (0*4602 as compared with
0*4247) . Thus, to judge by the mean coefficients of correlation, the
father is slightly more prepotent than the mother in heredity. The
mean coefficients of regression are for fathers 0*4244, and for mothers
0'4528, or in the ratio of 1 : T067, but the ratio of the paternal to
the maternal stature is T083, or this slight prepotency is still pre-
served if we judge the matter by regression coefficients. Again, we
notice an immense increase (0*2841 to 0'4247) in the correlation
between mothers and daughters when we compare the present results
with those of my earlier memoir. As an explanation of this, I have
already suggested the possibility of a law exhibiting a relation
between fertility and hereditary influence in mothers (§ 4 (ii) ).
(iii) The mean coefficient of correlation in stature between either
parent and a daughter may be taken to be — •
0*44±0'02.
Mathematical Contributions to the Theory of Evolution.
Thus, it does not differ very widely from the value suggested (0'41)
for sons, but is even further removed from the value (0'33) at first
determined by Mr. Gralton.
The greater correlation between sons and both parents noticed in
my first memoir is not borne out by the present statistics ; the
advantage is now — it is true to a much less extent — with daughters.
On the whole, I am not well satisfied with these results for
daughters. I can see no persistent source of error in the method of
collecting the observations, nor can I find any mistake in the calcu-
lations. I can only trust that more elaborate returns and measure-
ments of other characteristics may some day throw light on what
now appear to be anomalies.
(7) Finally, I may just notice what conclusions are to be drawn,
if we pay attention to the absolute difference in stature between
parents and daughters. Let Sem and dym be the differences in stature
between elder daughters and mothers, and younger daughters and
mothers respectively, then in inches we have for the corresponding
arrays :
cem = 0-7450-0-5707^.
fy* = 1-0406-0'5237A«.
Thus, arrays of younger daughters differ more from their mothers
in stature than arrays of elder daughters, if the mothers be more than
6'29 in. below the mean or more than 1*63 in. above the mean, or if
their deviations are not within the limits of about — 2'64 and 0'68
times the standard deviation of mothers. This gives us about 74 to
to 75 per cent, of elder sisters nearer in stature to their mothers than
younger sisters.
If fye, Sfy be the stature differences for fathers and daughters, we
have ;
ty = 4-4100-^0-5472/y.
fo = 4-1144-0-6039/i/.
Here, so long as the father lies between 5'21 in. less and 7'41 in.
more than the average, the array of younger daughters will more
nearly approach him in stature than the array of elder daughters.
These limits correspond to 1'89 and 2'68 times the standard devia-
tion of fathers. Accordingly, about 90 to 97 per cenfc. of younger
sisters are closer in stature to their fathers than elder sisters. Thus,
if we had started the discussion of the problem from a consideration
of the relative nearness in stature of daughter to father and mother,
we should have found that a great majority of younger sisters were
nearer to their fathers than their elder sisters, and a considerable
majority of elder sisters nearer to their mother than their younger
sisters. We might then have concluded that there were substantial
Magnetic Permeability of Liquid Oxygen and Liquid Air. 283
grounds for inferring the existence of a telegonic influence. But it
is clear that if there be anything of the nature either of a periodic or
of a secular change in stature going on, then since men are taller than
women, any group of younger women will appear closer to their
fathers than to their mothers, when compared with a group of elder
sisters. Thus, no legitimate argument as to a telegonic influence can
be based on such a result. I have purposely considered this method
of approaching the problem, because it is the method whioK first
occurred to me, as it probably may do to others. It can very
easily, however, lead to our mistaking for a real telegonic influence
an effect of periodic or secular evolution, or, indeed, of different con-
ditions of nurture.
(7) In conclusion, we may, I think, sum up the statistics dis-
cussed in this paper as follows : —
(i) So far as stature is concerned there is no evidence whatever of
a steady telegonic influence of the male upon the female
among mankind.
(ii) It is improbable that the coefficients of correlation which
measure the strength of heredity between parents and off-
spring are constant for all classes even of the same race.
For stature in the case of parents and offspring of both sexes, the
value 0'42, or say 3/7, may be taken as a fair working value, until
more comprehensive measurements are made. This makes heredi-
tary influence in the direct line stronger than has hitherto been
supposed.
(iii) The divergence between the results of this memoir and that
of the former memoir on " Regression, Heredity, and Pan-
mixia " would be fairly well accounted for, if there be a
hitherto unobserved correlation between the hereditary
influence and the fertility of woman.
t; On the Magnetic Permeability of Liquid Oxygen and Liquid
Air." By J. A. FLEMING, M.A., D.Sc., F.R.S., Professor of
Electrical Engineering in University College, London, and
JAMES DEWAR, LL.D., F.R.S., Fullerian Professor of
Chemistry in the Royal Institution, &c. Received Novem-
ber 20,— Read November 26, 1896.
The remarkable magnetic properties of liquid oxygen were pointed
out by one of us in a communication to the Royal Society in 1891,*
* ' Eoy. Soc. Proc.,' December 10th, 1891, vol. 51, p. 24. See a letter to the
President by Professor James Dewar, F.E.S.
284 Profs. J. A. Fleming and J. Dewar. On the
and were subsequently described to the Royal Institution in a lecture
delivered in 1892.* We have for some time past directed our attention
to the question of determining the numerical values of the magnetic
permeability and magnetic susceptibility of liquid oxygen, with the
object of determining not only the magnitude of these physical con-
stants, but also whether they vary with the magnetic force under which
they are determined.
Although a large number of determinations have been made by
many observers of the magnetic susceptibility of different liquids
taken at various temperatures, difficulties of a particular kind occur
in dealing with liquid oxygen. One method adopted for determining
the magnetic susceptibility of a liquid is to observe the increase of
mutual induction of two conducting circuits suitably placed, first in
air, and then when the air is replaced by the liquid in question, the
susceptibility of which is to be determined. A second method con-
sists in determining the mechanical force acting on a known mass
of the liquid when placed in a non-uniform magnetic field. Owing
to the difficulty of preventing entirely the evaporation of liquid
oxygen, even when contained in a good vacuum vessel, and the
impossibility of sealing it up in a bulb or tube, and having regard
to the effect of the low temperature of the liquid in deforming by
contraction and altering the conducting power of coils of wire placed
in it, it was necessary to devise some method which should be indepen-
dent of the exact constancy in mass of the liquid gas operated upon,
and independent also of slight changes in the form of any coils of
wire which might be used in it. After many unsuccessful preliminary
experiments the method which was finally adopted as best complying
with the conditions introduced by the peculiar nature of the substance
operated upon is as follows : —
A small closed circuit transformer was constructed, the core of which
could be made to consist either of liquid oxygen or else immediately
changed to gaseous oxygen, having practically the same temperature.
This transformer consisted of two coils, the primary coil was made of
forty-seven turns of No. 12 S.W.G. wire, this wire was wound into
a spiral, having a rectangular shape, the rectangular turns having a
length of 8 cm. and a width of 1'8 cm. This rectangular-sectioned
spiral, consisting of one layer of wire of forty-seven turns, was bent
round a thin brass tube, 8 cm. long and 2-| cm. in diameter, so that
it formed a closed circular solenoid of one layer of wire. The wire
was formed of high conductivity copper, doubly insulated with cotton,
and each single turn or winding having a rectangular form.
The turns of covered wire closely touched each other on the inner
circumference of the toroid, but on the external circumference were
* See 'Roy. Inst. Proc.,' June 10th, 1892, "On the Magnetic Properties of
Liquid Oxygen." Friday evening discourse, by Professor J. Dewar, F.R.S.
Magnetic Permeability of Liquid Oxygen and Liquid Air. 285
a little separated, thus forming apertures by which liquid could enter
or leave the annular inner core.
The nature of this transformer is shown in Fig. 1.
FIG. 1.
Diagram of the Closed Circuit Transformer used in the Experiments.
The mean perimeter of this rectangular-sectioned endless solenoid
was 13 J cm., and the solenoid had, therefore, very nearly 3*5 turns
per cm. of mean perimeter. When immersed in liquid oxygen a coil
of this kind will carry a current of 50 amperes. When a current of
A amperes is sent through this coil the mean magnetising force in
the axis of this solenoid is, therefore, represented by 4*375 times the
current through the wire, hence it is clear that it is possible to produce
in the interior of this solenoid a mean magnetising force of over
200 C.Gr.S. units. This primary coil had then wound over it, in two
sections, about 400 or 500 turns of No. 26 silk-covered copper wire to
form a secondary coil. The primary and secondary coils were sepa-
rated by layers of silk ribbon. The exact number of turns was not
counted, and as will be seen from what follows it was not necessary
Profs. J. A. Fleming and J. Dewar. On the
to know the number. The coil so constructed constituted a small
induction coil or transformer, with a closed air-core circuit, but which
when immersed in a liquid, by the penetration of the liquid into the
interior of the primary coil, became changed into a closed circuit
transformer, with a liquid core. The transformer so designed was
capable of being placed underneath liquid oxygen contained in a
large vacuum vessel, and when so placed formed a transformer of the
closed circuit type, with a core of liquid oxygen. The coefficient of
mutual induction of these two circuits, primary and secondary, is
therefore altered by immersing the transformer in liquid oxygen>
but the whole of the induction produced in the interior of the
primary coil is always linked with the whole of the turns of the
secondary coil, and the only form-change that can be made is a small
change in the mean perimeter of the primary turns due to the con-
traction of the coil as a whole. In experiments with this transformer
the transformer was always lifted out of the liquid oxygen into the
cold gaseous oxygen lying on the surface of the liquid oxygen, and
which is at the same temperature. On lifting out the transformer,
the liquid oxygen drains away from the interior of the primary coil,
and is replaced by gaseous oxygen of very nearly the same tem-
perature.
The vacuum vessel used had a depth of 60 cm. outside and 53 cm.
inside, and an internal diameter of 7 cm. It held 2 litres of liquid
oxygen when full ; but, as a matter of fact, 4 or 5 litres of liquid
oxygen were poured into it in the course of the experiment.
Another induction coil was then constructed, consisting of a long-
cylindrical coil wound over the four layers of wire, and a secondary
circuit was constructed to this coil, consisting of a certain number of
turns wound round the outside of the primary coil, and a small
adjusting secondary coil, consisting of a thin rod of wood wound over
with very open spirals of wire. The secondary turns on the outside
of the primary coil were placed in series with the turns of the thin
adjusting coil, and the whole formed a secondary circuit, partly out-
side and partly inside the long primary cylindrical coil, the coefficient
of mutual induction of this primary and secondary coil being capable
of being altered by very small amounts by sliding into or out of the
primary coil the small secondary coil. This last induction coil, which
will be spoken of as the balancing coil, was connected up to the small
transformer,, as just described, as follows : —
The primary coil of the small transformer was connected in series
with the primary coil of the balancing induction coil, and the two
terminals of the series were connected through a reversing switch
and ammeter with an electric supply circuit, so that a current of
known strength could be reversed through the circuit, consisting of
the two primary coils in series. The two secondary coils, the one on
Magnetic Permeability of Liquid Oxygen and Liquid Air. 287
the transformer and the one on the balancing induction coil, were con-
nected in opposition to one another through a sensitive ballistic
galvanometer in such a manner that on reversing the primary
current the galvanometer was affected by the difference between the
electromotive forces set up in the two secondary coils, and a very flue
adjustment could be made by moving in or out the adjusting coil of
the balancing induction coil.
The arrangement of circuits is shown in fig. 2.
FIG. 2.
/WW
Ww
Arrangement of the Circuits of the Transformer and Induction Coil.
For the purpose of standardising the ballistic galvanometer
employed, the primary coil of the balancing induction coil could
be cut out of circuit, so that the inductive effect in . the ballistic
galvanometer circuit was due to the primary current of the closed
circuit transformer alone. A resistance box was also included in the
circuit of the ballistic galvanometer. The resistance of the ballistic
galvanometer was about 18 ohms, and the resistance of the whole
secondary circuit 30'36 ohms. The experiment then consisted in
first balancing the secondary electromotive forces in the two coils
exactly against one another, then immersing the transformer in liquid
oxygen, the result of which was to disturb the inductive balance, and
in consequence of the magnetic permeability of the liquid oxygen core
being greater than unity, a deflection of the ballistic galvanometer
was observed on reversing the same primary current. The induction
288 Profs. J. A. Fleming and J. Dewar. On the
through the primary circuit of the small transformer is increased in
the same proportion that the permeability of the transformer core
is increased by the substitution of liquid oxygen for gaseous oxygenr
and hence the ballistic deflection measures at once the amount by
which the magnetic permeability of the liquid oxygen is in excess
over that of the air or gaseous oxygen forming the core of the trans-
former when the transformer is lifted out of the liquid. As a matter
of fact it was nfiver necessary to obtain the inductive balance pre-
cisely. All that was necessary was to observe the throw of the bal-
listic galvanometer, first when the transformer was wholly immersed
under the surface of liquid oxygen, and, secondly, when it was lifted
out into the gaseous oxygen lying on the surface of the liquid, the
strength of the primary current reversed being in each case the
same. In order to standardise the galvanometer and to interpret the
meaning of the ballistic throw, it was necessary to cut out of circuit
the primary coil of the balancing induction coil, and to reverse
through the primary circuit of the small transformer a known small
primary current, noting at the same time the ballistic throw pro-
duced on the ballistic galvanometer, this being done when the
transformer was underneath the surface of liquid oxygen. It will
be seen, therefore, that this method requires no calculation of any
coefficient or mutual induction, neither does it involve any know-
ledge of the number of secondary turns on the transformer, nor of
the resistance of the secondary circuit ; all that is necessary for a
successful determination of the magnetic permeability of the liquid
oxygen is that the secondary circuit of the transformer should
remain practically of the same temperature during the time when
the throw of the ballistic galvanometer is being observed, both
with the transformer underneath the liquid oxygen and out of the
liquid oxygen. If then the result of reversing a current of A
amperes through the two primary coils in series when the secondary
coils are opposed is to give a ballistic throw, D, and if the result of
reversing a small current a amperes through the primary coil of the
transformer alone is to produce a ballistic throw, d, then if p is the
magnetic permeability of liquid oxygen, that of the gaseous oxygen
lying above the liquid and at the same temperature being taken as
unity, we have the following relation : —
"T — = P- — !>
-d
a
which determines the value of /JL.
Deferring for a moment the correction to be applied to determine
the value of the magnetic permeability of liquid oxygen in terms of
that of a vacuum, the following are the results of observation : —
Magnetic Permeability of Liquid Oxygen and Liquid Air. 289
OBSERVATIONS ON MAGNETIC PERMEABILITY OP LIQUID OXYGEN.
Throws of Ballistic Galvanometer. Induction Coils balanced.
{ 4 '0 mm. to left T The transformer in liquid oxygen.
4 '2 „ „ V Primary current = 37 '8 amperes reversed
4 *3 „ „ J through primary coils.
I "] The transformer lifted out of liquid oxygen
17 -0 mm. to right | int,n 00ia gaacous oxygen at the same tem-
Exp. II. <j 17'5 „ „ }» perature.
18 '5 ,, „ j Primary current = 37*8 amperes reversed
J through primary coils.
r 3*2 mm. to left -i The transformer in liquid oxygen.
Exp. III. « 2 '5 „ „ I Primary current = 37 *2 amperes reversed
I 2*8 „ „ J through primary coils.
"^ The transformer lifted out of liquid oxygen
I 20 '0 mm. to right | into cold gaseous oxygen at the same tern-
Exp. IV. <{ 21 -0 „ „ [• perature.
• 21-3 „ „ I Primary current = 36 '8 amperes reversed
J through primary coils.
Throws of Ballistic Galvanometer in Standardising Observations.
Primary Coil of Balancing Coil disconnected.
. "| Corresponding to 0'1145 ampere reversed
through primary coil of the transformer,
" " the transformer being in liquid oxygen.
25 *° » " | The mean of these ballistic throws is the
' " " quantity denoted by d, and the current
25 '° " " J G'1145 ampere is the a in the formula above.
Standardising Observations repeated with another Current.
r T Corresponding to 0 '2639 ampere reversed
Exp. VI. \ 58'0mm- toright I through primary coil of transformer, the
t 58 "0 » » J transformer being in liquid oxygen.
Throius of Ballistic Galvanometer. Induction Coils balanced.
f "1 The transformer lifted out of liquid oxygen
into cold gaseous oxygen at same tempera-
Elp.TII. \ *'0»». to right ! ture
4'° » » Primary current = 8 '037 amperes reversed
I J through primary coils.
{0 '4 mm. to left •« The transformer in liquid oxygen.
0 .4 }) M I Current = 8 -095 amperes reversed through
0 '2 „ ,, J primary coils.
r 4-5 mm. to left 1 The transformer in liquid oxygen.
Exp. IX. J 4 '8 „ „ !> Current = 28 '8 amperes through primary
4-2 , J coils.
290
Exp. X.
Profs. J. A. Fleming and J. Dewar. On the
right
f
I 12
-| 12 -0
j 12*2
^
""I The transformer lifted out of liquid oxygen
'0 mm. to right into cold gaseous oxygen at the same tem-
perature.
Current = 28 '1 amperes reversed through
J primary coils.
The transformer in liquid oxygen.
{1 e ransormer n qu oxygen.
I Current = 28 '1 amperes reversed through
" " J primary coils.
Exp. XII.
The transformer in liquid
oxygen.
The transformer lifted out of liquid
oxygen into cold gaseous oxygen
at same temperature.
Current reversed
in primary coils,
in amperes.
Ballistic throw in
millimetres.
Deflection to the
right.
Current reversed
in primary coils,
in amperes.
Ballistic throw in
millimetres.
Deflection to the
right.
58-8
50-2
50-2
10-5
15-0
17-0
50-2
50-8
50-0
47-0
48-5
49-0
The above table shows the results of the observations made with
the small transformer alternately placed underneath the surf ace of
liquid oxygen, and then lifted up into the cold gaseous oxygen lying
above the surface of the liquid oxygen. It will be noticed that the
ballistic throws in each set of observations are not constant, but that
there is a tendency, usually, for the throw to increase if repeated,
whilst the transformer is still maintained in the same condition,
This is in all probability due to the fact that the continued passage
of the primary current heats the primary circuit of the balancing
induction, coil, and hence heats, also, by radiation, the secondary coil
of the balancing induction coil, and, therefore, by enlarging the area
of the adjusting coil, continually breaks down the inductive balance.
It was found necessary, therefore, to take the observations in groups
at equal intervals of time. First, a group of three observations was
taken, the transformer being in liquid oxygen, the balance being, as
nearly as possible, obtained. Then the transformer was lifted out of
the liquid oxygen, and the ballistic throws again taken, reversing the
same primary current ; next again immersed in liquid oxygen, and
finally once more taken out of the liquid oxygen. Taking the sets
Magnetic Permeability of Liquid Oxygen and Liquid Air. 291
of observations marked I, II, III, IV, the mean of the means of the
three observations in Sets I and III, corrected for the variation in
the primary current, were taken as the result of the measurement in
liquid oxygen, and this result was then compared with the ballistic-
throws in Set II.
Again, the mean of the means of sets of observations II and IV,,
properly corrected for variation of primary current, were compared
with the mean of the observations in Set III, and the result is to give
the data for calculating the permeability of the liquid oxygen for a
primary current through the primary coil of the transformer of about
37 amperes, corresponding very nearly to a mean magnetising force
of 166 C.Gr.S. units. The sum or difference of these means of the
throws, taken in the liquid oxygen and out of the liquid oxygen,
depending on whether they are on the opposite or the same side of
the zero of the scale, gives us the value of the quantity denoted by
D in the Table I below, and in the formula for the value of /*.
The above sets of observations, I, II, III, and IV, refer to a
primary current of about 37 amperes ; but similar sets of observa-
tions were taken with a primary current of about 8 amperes, 28
amperes, and 50 amperes respectively, and the result's of all these-
observations, which are included in the sets of observations, I to XII,
above given, have been reduced in Table I below to show the mag-
netic permeability of the liquid oxygen corresponding to different
megnetising currents. The set of observations marked Experiment
Valid Experiment VI in the above table of results, gives the observa-
tions for standardising the ballistic galvanometer. In the first case-
the primary coil of the balancing induction coil was cut out, and a
primary current, having a value of 0*1145 ampere, was reversed
through the primary coil of the transformer alone, and gave ballistic-
deflections as stated in the observations in Set V. These observations
serve to standardise the galvanometer and interpret the meaning of
the throw obtained when the large current is reversed through the
primaries of the two induction coils, the secondaries of which are
opposed. It will be noticed that one important advantage of the-
above- described method is that the quantity which we desired to
know, viz., the amount by which the presence of the liquid oxygen
increases the magnetic permeability of the core of the transformer, ia
the quantity which is measured directly, and that any error in the
measurement of this quantity does not affect the permeability to
anything like the same proportional extent. An error of about 10
per cent, in the measurement of the ballistic throw would only affect
the fourth place of decimals in the number representing the perme-
ability of the liquid oxygen.
The results of all the above observations, when reduced, are com-
prised in the following table : —
VOL. LX, z
292
Profs. J. A. Fleming and J. Dewar. On the
Table I.— Table of Results of Observations on the Magnetic
Permeability of Liquid Oxygen.
A -
Total ballistic
Ballistic throw
primary
current, in
amperes,
passing
through
primaries
of the
transformer
and balanc-
Correspond-
ing mean
magnetising
force in
C.G-.S. units
in primary
circuit of
transformer.
throw which
would be produced
if primary current
of A amperes were
reversed through
primary of trans-
former alone
*±a.
of galvanometer
resulting from
immersion of the
transformer in
liquid oxygen.
Transformer and
balancing
induction coil
being opposed
V- =
permeability
calculated
from
'-'-5
a
ing coil.
= D.
8*037
35-2
1734
4-33
1 -00250
28-13
123-0
6068
14-9
1 -00246
37-8
165-4
8153
21-18
1 -00260
36-8
161-0
7938
23-57
1 -00297
50-5
220-9
10894
32-98
1 -00304
The values of the permeability given in the foregoing table are not
all of equal weight.
The calculated value of JJL — 1 depends upon the observed ballistic
throw, and this cannot be read to a high degree of accuracy when the
throw is as small as 4 millimetres. We consider that the best result
is obtained by taking the mean of the values for the primary currents,
37'8, 36'8, and 50'5 amperes, and these values give /* = 1*00287, with
a probable accuracy of + 0'0002. This value of the permeability of
the liquid oxygen corresponds to a magnetising force lying between
166 and 220 C.Gr.S. units. It will be seen that this method is best
applicable to the determination of the permeability under large
magnetising forces ; and that these observations do not, in them-
selves, allow us to state whether the permeability is a constant for
all forces, or is a function of the value of the force.
In the next place the value is a relative one. The number 1*00287
is the ratio of the magnetic permeability of liquid oxygen to that of
the gaseous oxygen nearly at the same temperature resting upon the
surface of the liquid. We were not able by this method to detect the
difference between the permeability of the cold gaseous oxygen lying
on the surface of the liquid oxygen when in quiet ebullition, and which
has a temperature of about —182° C., but a density of at least three
times that of oxygen at 0° C., when compared with that of gaseous
oxygen at ordinary temperature, and under the normal pressure. In
a very valuable memoir on the determination of magnetic suscepti-
bilities, M. P. Curie* has examined the susceptibility of gaseous
*.' Theses presentees a la Faculte des Sciences de Paris pour obtenir le grade de
Docteur es Sciences Physiques,' par M. P. Curie, Paris, 1895.' This memoir is
of remarkable interest in many ways.
Magnetic Permeability of Liquid Oxygen and Liquid Air. 293
oxygen at different temperatures, and shown that between the limits
of 0° C. and 452° C. tbe magnetic susceptibility of oxygen (K) per
unit of mass is a function of the absolute temperature T, such that
106 K = 33700/T,
and that the value of K (per gram) at 0° C. is, therefore, 123/106.
The mass of 1 c.c. of oxygen gas at 0° C. and 760 mm. is O0014107
gram, and, reciprocally, the volume of one gram is 708'9c.c. at 0° C.
and 760 mm.
Hence the magnetic susceptibility of gaseous oxygen at 0° C. and
760 mm. per unit of volume (one c.c.) would be 123 x 0'00141 x 10~6
= 0'173 X 10~6, which is not very different from that obtained by
other observers.*
If then it could be supposed that gaseous oxygen followed the
same law down to —182° C., and taking the gas in a condition when
the density is nearly 0'00423, the volume susceptibility (&) at
—182° C. would be 1*6 x 10~6, and hence the permeability (/*)> where
should be 1-00002.
It is, however, certain that the susceptibility per unit of mass will
not continue to increase in accordance with the hyperbolic law,
because this would imply that at the absolute zero of temperature
the susceptibility would be infinitely great, and hence the above
number 1 '00002 gives a superior limit for the permeability of the
gaseous oxygen at — 182° C. lying on the surface of the liquid oxygen.t
The conclusion is that the correction to be applied to the above
observed value of ^ for the liquid oxygen, viz., T00287, to refer it to
a vacuum taken as unity, is altogether masked by the unavoidable
errors of experiment, and hence, pen ding further more exact measure-
ments, this may be taken as the value of the constant. We have,
however, at the present time, arranged a method which will enable
us we hope to determine directly the magnetic susceptibility of liquid
* .Faraday, ' Experimental Researches,' vol. 3, p. 502, gives a value for the sus-
ceptibility of gaseous oxygen at 60° F., referred to an equal volume of water as
unity, which, when reduced to absolute values by taking the magnetic susceptibility
-of water as 0'79 x 10~6, gives the value of the susceptibility as 0'143 x 10~6. Becquerel
found a value not very different.
f The critical temperature of oxygen is —118° C. The corresponding absolute
temperature is 155°. If we then put T = 155, in Curie's formula, 106K =
33700/T, we get 106K = 217'4, as his deduced extrapolated value for the sus-
ceptibility per unit of mass. Since the density of liquid oxygen, as determined
by one of us (J. Dewar) is l'137o, our value for the susceptibility per unit of
mass of the liquid oxygen is 228/l'1375 = 2007. These figures show that the
hyperbola does not represent the value of the susceptibility per unit of mass below
-the critical temperature.
294 Profs. J. A. Fleming and J. Dewar. On the
oxygen with, far greater accuracy. This method consists in observing
the mechanical force which acts upon a vacuum bulb or mass of
matter of known and very low susceptibility when it is suspended
free from gravity in a vessel of liquid oxygen, and in a variable mag-
netic field. Under these conditions a vacuum bulb of very thin
glass would behave like a strongly diamagnetic body, and if the mag-
netic susceptibility of the vacuum bulb or test mass is &15 and that of
liquid oxygen is &3 for equal volumes, then the apparent diamagnetic
susceptibility of the mass will be — (&2 — ki), and the actual para-
magnetic susceptibility of liquid oxygen may be deduced fro in a
knowledge of &i and — (&2 — &i)« By this method we hope to be
able to determine whether the permeability of liquid oxygen is a
function of the magnetising force. The latest experimental results
and measurements made with solutions of iron salts, such as those
made recently by Mr. J. S. Townsend,* appear to^show that the
magnetic permeability of solutions of these iron salts is a constant
quantity at least for a range of magnetic forces varying from 1 to
9 C.G.S. units.
The value, viz. 1*00287, as determined by us for the magnetic
permeability of liquid oxygen, shows that the magnetic susceptibility
(&) per unit of volume is 228/106. It is interesting to compare
this value with the value obtained by Mr. Town send for an aqueous
solution of ferric chloride, and which he states can be calculated by
the equation
10° & = 91-610— 0'77,
where w is the weight of salt in grams per cubic centimetre, and k
the magnetic susceptibility. Even in a saturated solution, w cannot
exceed O6, hence, from the above equation, we find the value of the
magnetic susceptibility of a saturated solution of one of the most para-
magnetic iron salts, viz., ferric chloride, is 54/106 for magnetic forces
between 1 and 9. This agrees fairly well with other determinations
of the same constant. On the other hand, the magnetic suscepti-
bility of liquid oxygen for the same volume is 228/106, or more than
four times as great. The unique position of liquid oxygen in respect
of its magnetic susceptibility is thus strikingly shown. It is, how-
ever, interesting to note that its permeability lies far below that of
certain solid iron alloys generally called non-magnetic.
The 12 per cent, manganese steel of Mr. B. A. Hadfield is usually
spoken of as non-magnetic, yet the magnetic permeability of this
last substance has been shown to be 1'3 or 1*4.
We have applied the foregoing method also to the determination
of the magnetic permeability of liquid air. Since liquid air which
* See 'Phil. Trans.,' A, rol. 187, 1896, "Magnetisation of Liquids," J. S.
Townsend, M.A.
Magnetic Permeability of Liquid Oxygen and Liquid Air. ^95
has been standing' in a vacuum vessel for any length of time has a
composition which varies with the time and which may contain an
much as 75 or 80 per cent, of oxygen, it was not to be expected that
very closely consistent results could be obtained in the case of air.
The following figures show, however, the observational results : —
PERMEABILITY OF LIQUID AIR.
Throws of Ballistic Galvanometer. Induction Coils balanced.
Exp. I.
Exp. II.
Exp. III.
Exp. IV.
Later.
Exp. Y.
Exp. VI.
Exp. VII.
Exp. VIII.
1 *5 mm. to right
1-2
17 -0 mm. to left
17-5 ,
0*3 mm. to right
0-3 ,
17 '0 mm. to left
17'0 „
17'3 ,
2-8 mm. to left
2-8 „
18 -8 mm. to left
19-2 „
19-4 „
19-8 „
3 '5 mm. to left
3-4 ,
22 '0 mm. to left
22-0 „
22-0 ,
The transformer in liquid air.
Current = 38 -0 amperes reversed through
primary coils.
The transformer lifted out of liquid air into
cold gaseous air at the same temperature
as before.
37 '5 amperes reversed.
The transformer in liquid air.
Current = 37 amperes reversed through
primary coils.
The transformer lifted out of liquid air into
cold gaseous air, and at the same tempera-
ture as before.
Current = 37 amperes reversed through
primary coils.
The transformer in liquid air.
Current = 367 amperes reversed through
primary coils.
The transformer lifted out of liquid air into
cold gaseous air, at the same temperature
as before.
Current = 37 amperes reversed through
primary coils.
The transformer in liquid air.
Current = 36*7 amperes reversed through
primary coils.
The transformer in liquid air.
Primary circuit of balancing coil cut out of
circuit and O'lllS ampere reversed through
primary of transformer to standardise the
ballistic galvanometer.
The results of these observations, when reduced, show that corre-
sponding to a primary current of 37'5 amperes, or a mean mag-
netising orce of 164 C.G.S. units, the apparent magnetic permea-
bility of liquid air in terms of gaseous air of the same temperature is
1-00240.
2 A
VOL. LX.
Anniversary Meeting.
At the time of these observations the liquid air used had probably
become almost entirely liquid oxygen by the evaporation of the
nitrogen. The figure, however, serves to check approximately that
of the liquid oxygen.
In conclusion, we desire to express our thanks to Mr. J. E. Petavel
for the assistance he has given to us in the above work. We hope
shortly to be able to make a further contribution to this portion of
the investigations on which we are engaged, on the electrical and
magnetic constants of liquid oxygen, and which will include a deter-
mination of the dielectric constant of liquid oxygen, made with the
object of determining the extent to which this substance obeys
Maxwell's law connecting magnetic permeability, dielectric constant,
and optical refractivity.
November 30, 1896.
ANNIVERSARY MEETING.
Sir JOSEPH LISTER, Bart., P.R.C.S., D.C.L., President, in the
Chair.
The Report of the Auditors of the Treasurer's Accounts, on the
part of the Society, was presented as follows : —
" The total receipts on the General Account during the past year,
including balances carried from the preceding year, amount to
£8,928 Is. 3d, and the total receipts on account of Trust Funds,
including balances from the preceding year, amount to £5,009 Os. 2d.
The total expenditure for the same period amounts to £7,287 12s. 3dL
on the General Account (including £300 on loan to the Coral Boring
Committee), and £3,347 11s. *ld. on account of Trust Funds, leaving
a balance on the General Account of £1,605 9s. 4c£. at the bankers
(which includes £1304 17s. 3d. on deposit — Dr. Ludwig Mond's gift,
£54 10s. Publication Grant Account, and £29 11s. lOd. Water
Research Account), and in the hands of the Treasurer a balance of
£34 19s. Sd. ; leaving also at the bankers a balance on account of
Trust Funds of £1,661 8s. 7d."
The thanks of the Society were voted to the Treasurer and Auditors.
Lists of Fellows deceased and elected.
The Secretary then read the following Lists : —
Fellows deceased since the last Anniversary (Nov. 30, 1895).
On the Home List.
297
Chambers, Charles.
Childers, Right Hon. Hugh Cul-
ling Eardley, F.R.G.S.
Erichsen, Sir John Eric, Bart.,
F.R.C.S.
Green, Alexander Henry, M.A.
Grove, Right Hon. Sir William
Robert, D.C.L.
Harley, George, M.D.
Hind, John Russell, LL.D.
Humphry, Sir George Murray,
M.D.
Johnson, Sir George, M.D.
Martin, Henry Newell, M.A.
Mueller, Baron Ferdinand von
K.C.M.G.
Prestwich, Sir Joseph, D.C.L.
Reynolds, Sir John Russell, Bart.,
M.D.
Richards, Sir George Henry,
Admiral, K.C.B.
Richardson, Sir Benjamin Ward,
M.D.
Sharp, William, M.D.
Trimen, Henry, M.B.
Verdon, Hon. Sir George Frederic,
K.C.M.G.
Walker, James Thomas, General,
R.E., C.B.
On the Foreign List.
Daubree, Gabriel Auguste.
Fizeau, Hippolyte Louis.
Gould, Benjamin Ap thorp.
Kekule, August.
Newton, Hubert Anson.
Withdrawn.
Bateman, James, M.A.
Fellows elected since the last Anniversary.
Clarke, Lieut. -Colonel Sir George
Sydenham, R.E.
Collie, J. Norman, Ph.D.
Downing, Arthur Matthew Weld,
D.Sc.
Elgar, Francis, LL.D.
Gray, Prof. Andrew, M.A.
Hinde, George Jennings, Ph.D.
Miers, Prof. Henry Alexander,
M.A.
Mott, Frederick Walker, M.D.
Murray, John, Ph.D.
Pearson, Prof. Karl, M.A.
Stebbing, Rev. Thomas Roscoe
Rede, M.A.
Stewart, Prof. Charles, M.R.C.S.
Temple, Sir Richard, Bart.,
G.C.S.I.
Wilson, William E.
Woodward, Horace Bolingbroke,
F.G.S.
Wynne, William Palmer, D.Sc.
298 Anniversary Meeting.
On the Foreign List.
Grandly, Albert.
Heim, Albert.
Kohlrausch, Friedrich.
Langley, Samuel Pierpont.
Lie, Sophus.
Metschnikoff, Elias.
Mittag-Leffler, Gosta.
Schiaparelli, Giovanni.
Lippmann, Gabriel.
The President then addressed the Society as follows :—
Nineteen Fellows and five Foreign Members have been taken from
the Royal Society by death since the last Anniversary Meeting.
The deceased Fellows are —
John Russell Hind, December 23, 1895, aged 73.
The Right Hon. Hugh Culling Eardley Childers, Japuary 29, 1896,
aged 69.
General James Thomas Walker, February 16, 1896, aged 69.
Charles Chambers, March, 1896, aged 61.
William Sharp, April 10, 1896, aged 91.
Sir John Russell Reynolds, May 29, 1896, aged 68.
Sir George Johnson, June 3, 1896, aged 78.
Sir Joseph Prestwich, June 23, 1896, aged 84.
The Right Hon. Sir William Robert Grove, August 2, 1896,
aged 85.
Alexander Henry Green, August 19, 1896, aged 64.
The Hon. Sir George Frederic Verdon, September 13, 1896,
aged 62.
Sir John Eric Erichsen, September 23, 1896, a^ed 78.
Sir George Murray Humphry, September 24, 1896, aged 76.
Baron Ferdinand von Mueller, October 9, 1896, aged 71.
Henry Trimen, October 18, 1896, aged 53.
George Harley, October 27, 1896, aged 67.
Henry Newell Martin, October 28, 1896, aged 44.
Admiral Sir George Henry Richards, November 14, 1896, aged 76.
Sir Benjamin Ward Richardson, November 21, 1896, aged 68.
The Foreign Members are —
Gabriel Auguste Daubree, May 29, 1896, aged 82.
August Kekule, July 13, 1896, aged 66.
Hubert Anson Newton, August 12, 1896, aged 66.
Hippolyte Louis Fizeau, September 18, 1896, aged 77.
Benjamin Apthorp Gould, November 27, 1896, aged 72.
Although biographical notices of nearly all will be found in the
* Proceedings,' there are some to whose labours I may make brief
reference to-day.
President's Address. 299
Sir William Grove presented the rare spectacle of steady and dis-
tinguished devotion to science in spite of the claims of an exacting
profession. Grove was an eminent lawyer. Called to the bar in 1835,
he was for some time kept from active work by ill health ; but he
subsequently acquired a considerable practice, and becoming a Queen's
Counsel in 1853, was for some years the leader of the South Wales
Circuit. His practice was mainly in patent cases, and the reputation
he obtained in that field led to his being appointed a member of the
Royal Commission on the Patent Laws. His work as an advocate
was, however, by no means confined to such matters ; he was one of
the counsel — Serjeant Shee and Dr. Kenealy being the others — who
defended the Rugeley poisoner, William Palmer, and he was engaged
in many other causes celebres.
The eminent position to which he had risen at the bar led to his
appointment in November, 1871, as a Judge of the old Court of
Common Pleas, a post which in 1875 was converted by the Judica-
ture Act into that of a Judge of the High Court. This office he held
until his retirement in 1887, when he became a member of the Privy
Council.
Throughout the greater part of his long and distinguished legal
career, Grove's love of science impelled him to devote a large share
of his energies to its pursuit. It is remarkable that his first paper,
which was communicated to the British Association in 1839, and
which also appeared in the ' Comptes Rendus,' and in Poggendorff's
' Annalen,' contained a description of the " Grove's cell," which
was afterwards used in every physical laboratory in the world. This
was succeeded by a long series of memoirs, chiefly on electrical sub-
jects, among which one of the best known is that on the gas battery.
In 1842 he delivered, at the London Institution, an address which
was, in the following year, developed into the celebrated series of
lectures : " On the Correlation of Physical Forces." In these he dis-
cussed what we should now call the transformations of energy ; and,
though Professor Tait, in his " Historical Sketch of the Science of
Energy," * assigns precedence in calling " attention to the gener-
ality of such transformations " to Mrs. Somerville, there can be no
doubt that Grove was an independent and very advanced thinker on
that subject.
For many years Sir William Grove took a very prominent part in
the affairs of the Royal Society, and was one of the most active pro-
moters of the reform of its constitution, which took place in 1847.
It is largely to his efforts that we owe our present system of electing
only a specified number of Fellows in each year. He was also one
of the founders of the " Philosophical Club."
He was President of the British Association in 1866, and, in the
* ' Thermodynamics/ p. 58.
300 Anniversary Meeting.
course of his address, observed : " The Kew Observatory, the petted
child of the British Association, may possibly become an important
national establishment ; and, if so, while it will not, I trust, lose its
character of a home of untrammelled physical research, it will have
superadded some of the functions of the Meteorological Department
of the Board of Trade, with a staff of skilful and experienced
observers."^ Although the British Association long ago handed
over the care of its " petted child" to a Committee appointed by the
Royal Society, the Society and the Association have lately appointed
a joint Committee to urge the Government to supply the funds for
converting the Kew Observatory into a " national establishment "
similar to the Reichsanstalt at Charlottenburg. We are thus striving
to realise to-day the suggestion thrown out, thirty years ago, by
Grove.
In Sir Joseph Prestwich we have lost almost the last link that
remained which connected geologists of the present day with the
founders of the science in the first half of this century. To him we
are indebted, not only for the first comprehensive classification of the
tertiary beds of this country — to several of which he assigned the
names by which they will henceforth be universally known — but,
also, for their correlation with the strata of the Paris Basin. To
him, also, is due the credit of having been the first to establish the
authenticity of the remains of human workmanship found in the
drift-deposits of the valley of the Somme, and of thus having laid
secure foundations on which arguments as to the extreme antiquity' of
man upon the earth may be based. In France his name was known
and respected as much as in England, and it would be hard to say
how much of the advance in geological knowledge during the last
sixty years was not due to his unintermitted labours, which extended
over the whole of that period.
The earliest scientific investigation of Armand Hippolyte Louis
Fizeau was 011 the use of bromine in photography, and was published
in 1841. He will always be remembered as the first who carried out
experiments designed to measure the velocity of light produced by a
terrestrial source, and travelling through a comparatively small dis-
tance near the surface of the earth. These observations, made in
1849, were very difficult ; but the value of the method employed is
attested by the fact that a quarter of a century afterwards it was
adopted by M. Cornu, and- that with the improved apparatus employed
by him it gave results of the highest accuracy.
A few years afterwards Fizeau performed another classical experi-
ment by which he measured the change in the velocity of light pro-
duced by the motion of the medium in which it travels.
* ' Correlation and Continuity.' Fifth Edition, 1867, p. 278.
President's Address. 301
He also devised an extremely delicate method (based on the inter-
ference of light) of determining the coefficients of thermal expansion
of small bodies, such as crystals. The instrument he designed has
been carefully studied by the Bureau International des Poids et
Mesures, with very satisfactory results.
On account of these and other researches, M. Fizean has, for nearly
half a century, occupied a conspicuous position among European
physicists. He was awarded the Rumford Medal in 1866, and
became a Foreign Member of the Royal Society in 1875.
Our distinguished Foreign Member, Professor Hubert Anson
Newton, Senior Professor of Mathematics at the Yale University,
New Haven, died at his home in New Haven on the 12th of August
last. He was born at Sherbourne, in the State of New York, in
1830 ; studied at Yale College, where he graduated in 1850, and was
called to the Chair of Mathematics in the University at the early
age of twenty-five.
On the organisation of the Observatory of the University in 1882,
Professor Newton was appointed Director ; and though he resigned
this position in 1884, the whole policy and success of the Observatory
ever since, and, indeed, its very existence, are in no small measure
due to his warm interest and untiring efforts.
Professor Newton's name will ever remain associated with his
important researches on Meteor Astronomy, beginning as early as
1860, and with his inquiry into the possible capture of comets by
Jupiter and other planets. His historical investigations, and discus-
sions of the original accounts, showed that the phenomena of meteor
showers are of a permanent character, and come within the range
of Celestial Dynamics, and that predictions of returning meteoric
displays are possible.
Professor Newton was President of the American Association for
the Advancement of Science in 1885, and was for many years an
Associate Editor of the 4 American Journal of Science.' He was a
man of noble character, held in universal esteem, and greatly beloved
by all those to whom he was persqnally known.
The death of August Kekale will be felt as a severe loss to
chemical science all over the world. Not only did his great activity
in original research enrich organic chemistry with many new and
interesting compounds, bu^ his announcement of the tetradic valency
of carbon, and, especially, his theoretical conception of the benzene
ring, gave an impulse to the study of structural chemistry which has
introduced order into the vast array of organic compounds, both of
the alcoholic and aromatic types, and has not, even yet, expended
itself. In recognition of his life-long work, the Council of the Royal
Society awarded Professor Kekule the Copley Medal in 1885.
Another Foreign Member who has passed away from us during
b02 Anniversary Meeting.
the year is the distinguished mineralogist and geologist, M. Daubree.
After leaving the Ecole Poly technique in 1832, he was sent on a
mission to investigate the modes of occurrence of tin-ore in Cornwall
and on the Continent. His reports showed such ability that he was
appointed Professor of Mineralogy and Geology at Strasburg, at the
age of 25; afterwards (1861-2)' he became Professor of Geology at
the Musee d'Histoire Naturelle at Paris, and at the same time Pro-
fessor of Mineralogy at the Ecole des Mines ; in the same year he
succeeded to the Chair at the Institut vacated by M. Cordier. From
1872 to 1884, when the rules of the Service made retirement by
reason of age compulsory, he acted as Director of the Ecole des
Mines. M. Daubree was the leader in France in experiments for the
synthetic reproduction of minerals and rocks, and his laboratory
furnace was the first to yield crystals of oxide of tin having the
lustre, colour, and hardness of the mineral cassiterite; his memoir
on the zeolites and other minerals, produced since Roman times
through the action of the hot springs of Plombieres on the bricks
arid concrete, has been of general interest both to mineralogists and
geologists. Other important experiments led him to infer that
circulating water, rather than heat or vapours, has been the essential
agent in all phenomena of rock transformation. M. Daubree gave
much attention to the description and classification of meteorites,
and made numerous experiments relative to the reproduction of
material having similar characters.
Tiie Council was much occupied during the earlier part of the
session with the consideration of the proposed " Standing Orders "
relating to the conduct of the meetings, and to the Publications of
the Society — a subject which has engaged the anxious attention of
previous Councils. In framing these Standing Orders two principal
objects were kept in view. Firstly, to increase the interest of the
meetings by giving greater freedom in the conduct of them, and
by enlarging the opportunities for discussion ; and secondly, to
obtain a more secure, and, at the same time, more rapid judgment
as to the value of communications made to the Society ; so that,
while the high standard of the 'Philosophical Transactions' is
retained, or even raised, greater rapidity in the publication of these
and of the ' Proceedings ' may be attained. To secure these latter
objects, the Council has called to its aid, in the form of Sectional
Committees, a number of Fellows much greater than that of the
Council itself, to whom will be entrusted the task of reviewing the
communications to the Society, and of making to the Council such
recommendations with respect to them as may seem desirable. It is
further probable that by using the special knowledge of the several
Sectional Committees in the detailed consideration of special questions,
the Council will have more time at its disposal than it has at present
President's Address. 303
to consider the matters of larger policy which are so frequently
brought before it.
It soon became evident that no satisfactory Standing Orders
securing these advantages could be drawn up which would not be in
some way or other inconsistent with the Statutes at present in opera-
tion. It was accordingly resolved to modify the Statutes ; and this
has been done by giving to certain Statutes a more general form
tlian that in which they have for a long time appeared, so that such
alterations of detail as may from time to time seem desirable may
be effected by changes in the Standing Orders only, without inter-
fering with the Statutes. I gladly avail myself of this opportunity
of acknowledging the great help which the Council received from
Mr. A. B. Kempe, in respect to the many legal points which arose
in connection with the change of Statutes. A copy of the Statutes,
as amended during the present session, as well as of the Standing
Orders adopted, will be found in the Year-book, which has been
instituted by one of the new Standing Orders, and which will be pub-
lished each year, as soon after the Anniversary Meeting as possible.
The International Conference called to consider the desirability
and possibility of compiling and publishing, by international co-
operation, a Complete Catalogue of Scientific Literature, was duly
held ; and the Society may be congratulated on the successful issue
of a meeting, to the preparations for which a special International
Catalogue Committee, appointed by, and acting under the authority
of, the Council, had devoted much time and labour. The Conference
met in the apartments of the Society on July 14, 15, 16, and 17,
under the presidency of the Bight Hon. Sir J. Gorst, Vice-President
of the Committee of Council on Education, and was attended
by forty- one delegates, representing nearly all countries interested
in science. The Society was represented by the Senior Secretary,
Professor Armstrong (Chairman of the International Catalogue
Committee), Mr. Norman Lockyer, Dr. L. Mond, and Professor
Riicker. Four other Fellows of the Society, General Strachey, Dr.
D. Grill, Professor Liversidge, and Mr. R. Trimen were among the
delegates appointed by the Indian and Colonial Governments.
The Conference resolved that it was desirable to compile and
publish a catalogue of the nature suggested in the original circular
issued by the Royal Society, the administration being carried out by
a Central International Bureau, under the direction of an Inter-
national Council, with an arrangement that each of such countries
as were willing to do so, should, by some national organisation,
collect and prepare for the Central Bureau all the entries belonging
to the scientific literature of the country. It was further resolved
that the language of the catalogue should be English, and a proposal
that the Central Bureau should be placed in London was carried by
304 Anniversary Meeting.
acclamation. The Conference finding itself unable to accept any of
the systems of classification proposed, requested the Royal Society to
form a committee which shonld consider this and other matters which
were left undecided by the Conference. The Council are already
taking steps to perform the duties thus entrusted to them by the
Conference.
The delegates of the Society reported that the whole proceedings
of the Conference were carried on with remarkable good feeling,
and even unanimity, and that the confidence felt and expressed by the
various delegates in the fitness of the Royal Society to complete the
work begun by the Conference was most gratifying.
In connection with the fact that the proposed International Cata-
logue is to be in part arranged according to subject matter, it may be
stated that the Council, acting upon a resolution of the International
Catalogue Committee, have taken steps towards the practice of append,
ing subject indices to the papers published by the Society, and have
recommended th'e same practice to other Societies.
The work connected with the Society's own Catalogue is progressing.
Vol. XI, the last of the decade 1874-83, has been published, and the
preparation of the Supplement, which has been found necessary for
this and preceding decades, is being pushed on.
For the Subject Index to the Catalogue, slips have been prepared,
and the Catalogue Committee will soon have to advise the Council
as to the system of classification to be adopted. .
The Grant of £1000 in aid of publications, which My Lords of the
Treasury promised last summer to place upon the Estimates of this
year, has been sanctioned by Parliament, and a moiety of it has
already been paid to the Society. The Council have already felt the
great advantage of having this money at their disposal, and have
framed Regulations for its administration which they trust will be
found to work satisfactorily.
The Council have made some small changes (which have been
approved by My Lords of the Treasury) in the Regulations for the
administration of the Government Grant of £4000 in aid of Scientific
Inquiries, directed chiefly towards more effectually securing that
Grants made should be expended for the purpose for which they were
given, and that objects of permanent interest obtained by Grants
should be properly disposed of. The only two Grants made this
year which call for special mention are that of £1000 to the Joint
Permanent Eclipse Committee of the Royal and Royal Astronomical
Societies, for observations of the Solar Eclipse of August, and that
of £800 for boring a coral reef in the Pacific Ocean, administered by
the Committee appointed by the Royal Society, both drawn from the
Reserve Fund.
The Expedition to bore the Coral Reef received valuable assistance
President's Address. 305
from My Lords of the Admiralty, who directed H.M.S. " Penguin "
to carry the observers from Sydney, N.S.W., to Funafuti, the seat of
the boring, and to render the Expedition all possible help during the
whole of the operations. T desire to express on behalf of the Society
our recognition of this renewed token of the willingness of My Lords
of the Admiralty to further scientific inquiry. Though the full
Report of the Expedition has not yet reached the Council, informa-
tion has been received fco the effect that the boring operations had to
be suspended when a depth of only 75 feet had been reached ; a
layer of sand and boulders presenting obstacles which the experts
employed were unable to overcome. It js much to be regretted that
an undertaking, which promised scientific results of very great value
has thus so far failed.
The appeals of the Council to H.M. Minister for Foreign Affairs
and to My Lords of the Admiralty for assistance to the Eclipse
Expeditions met with most cordial and effective response, for which
-we would express our gratitude. We also desire to acknowledge the
courtesy shown and help afforded to the observing parties in
Norway and Japan by the respective Governments of those countries,
and to record our high appreciation of the enthusiastic and effective
aid given to those under the direction of Mr. Norman Lockyer, at
Vadso, by Captain King Hall and the Officers and crew of H.M.S.
" Volage " ; to Dr. Common, also in Norway, by Commodore Atkin-
son, of H.M.S. " Active " ; to the Astronomer Royal's party, in Japan,
by the Officers of H.M.S. " Humber," " Pique," and " Linnet," kindly
detached by Admiral Sir A. Buller to convey the various members of
the expedition to and from Yezo, and to aid them during the observa-
tions.
Both in Norway and in Japan unfavourable weather rendered to a
large extent nugatory the elaborate preparations which had been
made for observing the eclipse. But British astronomy was
splendidly saved from failure on this important occasion by the
munificence and public spirit of Sir George Baden Powell, who fitted
up, at his own expense, and accompanied an expedition in his yacht
" Otaria " to Novaya Zemlya. The instruments employed were pro-
vided by our Fellows, Mr. Lockyer and Mr. Stone, of the Radcliffe
Observatory, Oxford; and the observations were entrusted to
Mr. Shackleton, one of the computers employed by the Solar Physics
Committee. In brilliant weather photographic observations were
made, which promise to yield novel results of a highly important
character.
At the request of the President of the Board of Trade the Council
nominated, in March, Professors Kennedy and Roberts- Austen as
two members of a Committee to investigate the loss of strength in
steel rails. So far as I am aware, the Committee has not yet made
306 Anniversary Meeting.
its report. More recently, in July, the Council, at the request of
H.M. Secretary for Colonial Affairs, appointed a Committee to con-
sider, and if necessary to investigate, in conjunction with Surgeon-
Major Bruce, who has made important researches in the matter, the
disease caused in cattle in Africa by the Tsetse Fly. The Committee
is still engaged on the inquiry.
We believe that the Council, in cordially responding to requests
like the above, and in freely placing at the disposal of H.M. Govern-
ment its scientific knowledge and its acquaintance with scientific
men, is performing one of its most important functions. The
Council of the Royal Society is again and again called upon to
approach H.M. Government on behalf of the interests of science, and
when it does so always meets with a cordial reception and a respect-
ful hearing, even on occasions when public necessities prevent a
favourable reply being given to its requests. In return, the Council
believes it to be its duty (when called upon to do so), not only to
place its own time and labour ungrudgingly at the service of H.M.
Government, but also to ask for the co-operation of other Fellows of
the Society, or even other scientific men not Fellows of the Society,
feeling confident that whenever the matter in hand has practical
bearings beyond the simple advancement of Natural Knowledge, the
value of a scientific man's time and energy will be duly considered.
Some correspondence has taken place with the War Office relative
to resuming the borings in the Delta of the Nile, which were carried
on for a time some years ago, and which, though not completed,
yielded valuable results. The Expedition to the Soudan has, how-
ever, prevented anything being done. The Council learn with
pleasure that the old borings, undertaken for a purely scientic object,
have indirectly been a valuable means of supplying certain districts
of the Delta with sweet water.
If anything had been needed to justify the meetings for discussion
recently established, it would have been supplied by the brilliant
success of that held during the present session on Colour Photo-
graphy. On that occasion, M. Lippmann gave us a demonstration
of results of unprecedented beauty, obtained by extremely simple
means, though based on profound mathematical reasoning. Such
meetings can only prove fruitful when they are held in consequence
of some theme needing such a discussion as is afforded by a special
meeting ; and their occurrence must therefore be uncertain and
irregular. The purpose for which they were instituted would be
frustrated if they were held at times fixed in any formal way, irre-
spective of whether they were needed or no.
Three of the informal gatherings recently instituted, limited to
Fellows of the Society, have been .held during the session, and were
judged to be very successful.
President's Address. 307
The Council has had occasion during the past session fco present
an address of condolence to Her Majesty, the Patron of the Society,
on the lamented death of Prince Henry of Battenberg, and to
the Royal Academy on the occasion of the death of their President,
Lord Leighton. In the absence of Council, during the recess, I sent
another message of sympathy 011 the death of Sir J. Millais.
I had the privilege of presenting on behalf of the Council, an
address of congratulation to our late President, Lord Kelvin, on the
occasion of his Jubilee, nobly celebrated in Glasgow last summer, by
a very remarkable concourse of scientific men from all parts of the
world, assembled to do him honour.
Addresses were also sent to our Foreign Member, Professor Can-
nizzaro, on the celebration of his seventieth birthday, and to the
University of Princeton, New Jersey, U.S.A., on the occasion of its
Sesquicentenary Anniversary.
Under the guidance of the Scientific Relief Committee, the Council
has during the year granted £100 to assist scientific persons or their
relatives in distress. The Council desires to call the attention of the
Fellows to the fact that, during the year, as during past years, the
income of the fund has exceeded its expenditure, and that more aid
could be given -than has been given. With the view of increasing
the usefulness of the fund, the Council has added to the list of those
who can make representations to the Council concerning relief
the Presidents of the Mathematical, Physical, and Entomological
Societies.
I cannot but give expression to my deep regret, shared, I am sure,
by every Fellow, that Lord Rayleigh, whose tenure of office as
Secretary has been marked as much by faithful devotion to the in-
terests of the Society as by scientific brilliancy, has thought it right,
in consequence of increasing pressure of other engagements, to
retire. But I rejoice that the Council can submit to your suffrages a
man well qualified to wear the mantle laid down by Lord Rayleigh.
The Fellows will be pleased to learn that Mr. Rix, who was com-
pelled by the condition of his health a year ago, to resign the
position which he had held for many years with such great advantage
to the Society, has much improved under the lighter labour of the
Clerkship to the Government Grant Committee.
As his successor in the office of Assistant- Secretary, the Council,
out of eighty-four candidates, unanimously selected Mr. Robert
Harrison, who entered upon his duties on the 24th of April last.
The scientific work of the Society during the past year has been
full of deep and varied interest. Early in the session the announce-
ment of Rontgen's great discovery burst upon the world. Its won-
derful applications to medicine and surgery attracted universal
attention to it ; and physicists everywhere have since been engaged
308 A nniversary Meeting.
in investigating the nature of the new rays. Perhaps no outcome
of such inquiries has been more remarkable than the fact observed
by our Fellow Professor J. J. Thomson, that the rays have the power
of discharging electricity, both positive and negative, from a. body
surrounded by a non-conductor ; a mass of paraffin wax, for example,
behaving in their path for the time being like a conductor of elec-
tricity.
It appears that Lenard had before observed the discharge of both
kinds of electricity through air by the rays with which he worked.
Lenard's rays, however, differ from Rontgen's in being deflectable by a
magnet, implying, in the opinion of most British physicists, that they
are emanations of highly electrified particles of ponderable matter,
while Rontgen's are regarded as vibrations in the ether. The question
naturally arises whether Lenard, in the observations referred to, may
not have been working with a mixture of Rontgen's rays and his
own. While points like these are still under discussion by experts,
we cannot but feel that the letter X, the symbol of an unknown
quantity, employed originally by Rontgen to designate his rays, is
still not inappropriate.
I have before referred to Lippmann's beautiful demonstration
and discussion of colour photography in one of our meetings.
Very important researches have been made both by Lord Rayleigh
and by Professor Ramsay into the physical properties of the new
substance, helium, discovered by Ramsay in the previous session.
Among their most striking results is the fact ascertained by Rayleigh
that the refractivity of helium is very much less than any previously
known, being only O146 ; between three and four times less than that
of hydrogen, the lowest that had before been observed, although
helium has more than twice the density of hydrogen. And equally
surprising is Ramsay's observation of the extraordinary distance
through which electric sparks will strike through helium, viz.,
250 or 300 mm. at atmospheric pressure, as compared with 23 mm.
for oxygen and 39 for hydrogen. Such properties appear to indicate
that in helium we have to do- with an exceedingly remarkable
substance.
The density of helium appears to be really slightly different
according to the mineral source from which it is obtained ; and this
circumstance seemis to give countenance to the opinion arrived at by
Lockyer and also by Runge and Paschen, from spectroscopic investi-
gation, that helium is not a perfectly pure gas. But whatever other
gas or gases may be mixed with it, they must be as inert chemically
as the main constituent ; for all Ramsay's elaborate attempts to
induce it, or any part of it, to combine with other bodies have
entirely failed.
Professor Roberts- Austen, in the Bakerian lecture, brought before
President's Address. o09
us astonishing evidence that metals are capable of diffusing into each
other, not only when one of them is in the state of fusion, but
when both are solid. We learned that if clean surfaces of lead and
gold are held together in vacuo at a temperature of only 40° for
four days, they will unite firmly and can only be separated by a force
equal to one-third of the breaking strain of lead itself. And gold
placed at the bottom of a cylinder of lead 70 mm. long thus united
with it, will have diffused to the top in notable quantities at the end
of three days. Such facts tend to modify our views concerning
the mutual relations of the liquid and solid states of matter.
Such are a few samples of the many highly interesting communica-
tions we have had in physics and chemistry. On the biological side
also, there has been no lack of important work. Of this I may refer
to one or two instances.
Professor Schafer has given us an account of the well devised
experiments by which he has conclusively established that the spleen
is on the one hand capable, like the heart, of independent rhythmical
contractions, and, on the other hand, has those contractions controlled
by the central nervous system acting through an extraordinary
number of efferent channels.
Professor Farmer and Mr. Lloyd- Williams made a very beautiful
contribution to biology in the account they gave of their elaborate
investigations on the fertilisation and segmentation of the spore in
Fucus. Especial interest attached to this communication, from the
fact that it described in a vegetable form exactly what had been
established by Oscar Hertwig in Echinodermata, viz., that out of the
multitude of fertilising elements that surround the female cell, one
only enters it and becomes blended with its nucleus.
Lastly, I may mention the very remarkable investigation into the
development of the Common Eel, which was described to us a
fortnight ago by Professor Grassi, to which I shall have occasion
to refer in some detail when speaking of his claims to one of the
Society's medals.
These, as I have before said, are but samples of what we have had
before us ; but I think they are in themselves sufficient to justify the
statement that, in point of scientific interest, the past year has been
in no degree inferior to its predecessors.
COPLEY MEDAL.
Professor Gad Gegenbaur, For. Mem. U.S.
The Copley Medal for 1896 is given to Carl Gegenbaur, Professor
of Anatomy in Heidelberg, in recognition of his pre-eminence in the
science of Comparative Anatomy or Animal Morphology. Professor
310 Anniversary Meeting.
Gegenbaur was born in 1826, and a few weeks ago his 70th birthday
was celebrated by his pupils (who comprise almost all the leading
comparative anatomists of Germany, Holland, and Scandinavia) by
the presentation to him of a " Festschrift " in three volumes. Gegen-
baur is everywhere recognised as the anatomist who has laid the
foundations of modern comparative anatomy on the lines of the
theory of descent, and has to a very large extent raised the building
by his own work. His ' Grundziige der vergleichenden Anatomie '
was first published in 1859, when he was 33 years old. In the second
edition, published in 1870, he remodelled the whole work, making
the theory of descent the guiding principle of his treatment of the
subject. Since then he has produced a somewhat condensed edition
of the same work under the title of ' Grundriss ' (translated into
English and French), and now, in his 71st year, he is about to
publish what will probably be the last edition of this masterly
treatise, revising the whole mass of facts and speculations accumu-
lated through his own unceasing industry and the researches of his
numerous pupils during the past quarter of a century.
Gegenbaur may be considered as occupying a position in morph-
ology parallel to that occupied by Ludwig in Physiology. Both were
pupils of Jahannes Miiller, and have provided Europe with a body of
teachers and investigators, carrying forward in a third generation
the methods and aims of the great Berlin professor. Gegenbaur's
first independent contribution to science was published in 1853. It
was the outcome of a sojourn at Messina in 1852, in company with
two other pupils of Johannes Miiller, namely Albert Kolliker (still
professor in Wiirzburg) and Heinrich Miiller, who died not long
afterwards. These young morphologists published the results of
their researches in common. Gegenbaur wrote on Medusae, on the
development of Echinoderms, and on Pteropod larvae. A long list
of papers on the structure and development of Hydrozoa, Mollusca,
and various invertebrata followed this first publication. The greatest
interest, however, was excited among anatomists by his researches on
the vertebrate skeleton (commenced already in 1849 with a research,
in common with Friedreich, on the skull of axolotl). In a series of
beautifully illustrated memoirs he dealt with and added immensely
to our knowledge of the vertebral column, the skull, and the limb-
girdles and limbs of Vertebrata, basing his theoretical views as to
the gradual evolution of these structures in the ascending series of
vertebrate forms upon the study of the cartilaginous skeleton of
Elasmobranch fishes, and on the embryological characters of the
cartilaginous skeleton and its gradual replacement by bone in higher
forms. His method and point of view were essentially similar to
those of Huxley, who independently and contemporaneously was
engaged on the same line of work.
President's Address. 311
For many years Gegenbaur was professor in Jena, where he was
the close friend and associate of Ernst Haeckel, but in 1875 he
accepted the invitation to the Chair of Anatomy in Heidelberg, and
in view of the increased importance of his duties as a teacher of
medical students, and therefore of human anatomy, though still con-
tinuing his researches on vertebrate morphology, he produced a
large treatise on that subject, which has ran through two editions.
In this work he made the first attempt to bring, as far as possible,
the nomenclature and treatment of human anatomy into thorough
agreement with that of comparative anatomy, and to a very large
extent the changes introduced by him have influenced the teaching
of human anatomy throughout Europe and America.
There is probably no comparative anatomist or embryologist in
any responsible position at the present day who would not agree in
assigning to Gegenbaur the very first place in his science as the
greatest master and teacher who is still living amongst us. He is
not only watching in his old age the developments of his own early
teachings and the successful labours of his very numerous disciples,
but is still exhibiting his own extraordinary industry in research, his
keenness of intellectual vision, and his unrivalled knowledge and
critical judgment.
ROYAL MEDAL.
Sir Archibald GeiJcie, F.R.S.
One of the Royal Medals is conferred on Sir Archibald Geikie, on
the ground that of all British geologists he is the most distinguished,
not only as regards the number and the importance of the geological
papers which he has published as an original investigator, but as one
whose educational works on geology have had a most material
influence upon the advancement of scientific knowledge.
His original papers range over many of the main branches of
geological science. His memoir upon the ' Glacial Drift of Scotland '
(1863) is one of the classics in British geology. His work on the
' Scenery of Scotland, viewed in connection with the Physical
Geology ' (1865) was the first successful attempt made to explain
the scenery of that country upon scientific principles, and is still
without a rival. His papers on the " Old Red Sandstone of Western
Europe " (1878-79) gave for the first time a clear and convincing
picture of the great lake period of British geology, founded upon
personal observation in the field.
His many original contributions to the Volcanic History of the
British Isles form a succession of connected papers, crowded with
important observations and discoveries, and brilliant and fertile
generalizations respecting the abundant relics of former volcanic
VOL. LX. - 1J
312
Anniversary fleeting.
activity in the British Isles from the earliest geological ages to
Middle Tertiary times.
In the first series of these papers — commencing* with the " Chrono-
logy of the Trap Rocks of Scotland" (1861), and ending with the
" Tertiary Volcanic Rocks of the British Isles" (1869), abundant
original proofs were advanced of the activity of volcanic action in the
Western Isles of Scotland, and of its long duration in geological
time. The second series (1871-88) was especially distinguished by
the publication of his remarkable paper on the " Carboniferous Vol-
canic Rocks in the Basin of the Firth of Forth," our earliest, and, as
yet, oar only monograph on a British volcanic area belonging to a
pre-Tertiary geological system. The third series (begun in 1888)
commenced with his memoir on the " History of Volcanic Action
during the Tertiary Period in the British Isles," a paper which is by
far the most detailed and masterly contribution yet made to the
subject, and for which the Brisbane Medal was awarded him by the
Royal Society of Edinburgh ; and this succession of papers has been
followed by the publication of others of almost equal importance.
Sir Archibald Geikie has also written many papers and memoirs
bearing upon geological processes arid their effects, which have become
permanent parts of oar scientific literature.
While carrying out this highly important original work in Geology,
Sir Archibald has most materially contributed to the advancement
and diffusion of scientific knowledge by his many educational works
upon Geology and Physical Geography. His ' Elementary Lessons
on Physical Geography' has passed through several English and
Foreign editions ; his ' Outlines of Field Geology ' is now in its
fifth edition ; and his article on Geology — originally contributed to
the ' Encyclopaedia Britannica ' in 1879 — was afterwards expanded
by him into his well-known ' Text- book of Geology,' which has
become the acknowledged British standard of Geology in general.
ROYAL MEDAL.
Professor C. V. Boys.
The other Royal Medal is awarded to Professor Boys, who has
given to physical research a method of measuring minute forces far
exceeding in exactness any hitherto used, by his invention of the
mode of drawing quartz fibres, and by his discovery of their remark-
able property of perfect elastic recovery.
Professor Boys has himself made several very important researches
in which he has employed these fibres to measure small forces. Using a
combination of a thermo- junction with a suspended coil in a galvano-
meter of the usual D'Arsonval type, a combination first devised by
D'Arsonval himself, Professor Boys developed the idea in the micro-
Presidents A ddress, 313
radiometer, an instrument rivalling the bolometer in the measurement
of small amounts of radiation. Its sensitiveness and accuracy were ob-
tained in part by the use of a quartz fibre to suspend the coil, in part
by the admirable design of every portion of the instrument. Professor
Boys was the first to show its value in an investigation into the
radiation received from the moon and stars.
In his great research on the value of the Newtonian constant of
attraction, Professor Bovs used quartz fibres to measure the gravitation
forces between small bodies by the Mich ell- Cavendish torsion method.
He redesigned the whole of the apparatus, and, calculating what
should be the dimensions and arrangements to give the best results,
he was led to the remarkable conclusion that accuracy was to be
gained by a very great reduction in the size of the apparatus. This
conclusion he justified by a determination of the value of the New-
tonian constant, which is now accepted as the standard.
Professor Boys has also made some remarkable studies by a photo-
graphic method of the motion of projectiles, and of the air through
which they pass.
All his work is characterised by the admirable adjustment of.
the different parts of the apparatus he uses to give the best results.
His instruments, are, indeed, models of beauty of design.
RUMFORD MEDAL.
Professor Philip P. Lenard and Professor W. C. Rontgen.
In tlr^ case of the Rumford Medal, the Council have adopted a
course, for which there are precedents in the awards of the Davy
Medal, but which is, as far as the Rumford Medal itself is concerned,
a new departure. They have decided to award the Medal in dupli-
cate. It has often happened in the history of science that the same
discovery has been made almost simultaneously and quite indepen-
dently by two observers, but the joint recipients of the Rumford
Medal do not stand in this relation to each other. Each of them may
fairly claim that his work has special merits and characteristics of
its own. To day, however, we have to deal, not with points of
difference, but with points of similarity. There can be no question
that a great addition has recently been made to our knowledge
of the phenomena which occur outside a highly exhausted tube
through which an electrical discharge is passing.
Many physicists have studied the luminous and other effects which
take place within the tube ; but the extension of the field of inquiry
to the external space around it is novel and most important. There
can be no doubt that this extension is chiefly due to two men — Pro-
fessor Lenard and Professor Rontgen.
2 B 2
314 Anniversary Meeting.
The discussion which took place at the recent meeting of the
British Association at Liverpool proved that experts still differ as to
the exact meaning and causes of the facts these gentlemen have dis-
covered. No one, I believe, disputes the theoretical interest which
attaches to the researches of both ; or the practical benefits which the
Rontgen rays may confer upon mankind as aids to medical and
surgical diagnosis. But whatever the final verdict upon such points
may be, the two investigators whom we honour to-day have been
toilers in a common field, they have both reaped a rich harvest,
and it is, therefore, fitting that the Royal Society should bestow upon
both of them the Medal which testifies to its appreciation of their
work.
DAVY MEDAL.
Professor Henri Moissan.
The Davy medal is given to Professor Henri Moissan.
Notwithstanding the abundant occurrence of fluorine in nature, the
chemical history of this element and its compounds has until recently
been scanty in the extreme, and, as far as the element in the free
state is concerned, an entire blank. And yet from its peculiar posi-
tion in the system of elements, the acquisition of a more extended
knowledge of its chemical properties has always been a desideratum
of the greatest scientific interest.
The frequent attempts which have been made from time to time to
clear up its chemical history have been constantly baffled by the
extraordinary difficulties with which the investigation of this element
is beset.
Thanks to the arduous and continuous labours of M. Moissan, this
void has been filled up. He has effected the isolation of fluorine in a
state of purity, and prepared new and important compounds, the
study of which has placed our knowledge of the chemical and
physical properties of this element on a level with that of its imme-
diate allies.
During the last few years M. Moissan has turned his attention to
the study of chemical energy at extremely high temperatures, and by
the aid of the electric furnace, which he has contrived, he has
succeeded in obtaining a large number of substances whose very
existence was hitherto undreamt of. It is impossible to set bounds
to the new field of research which has thus been opened out. The
electric furnace of M. Moissan has now become the most powerful
synthetical and analytical engine in the laboratory of the chemist.
On studying the accounts which Moissan has given of his re-
searches, we cannot fail to be struck with the originality, care, perse-
verance and fertility of resource with which they have been carried
President's Address. 315
on. The Davy Medal is awarded to him in recognition of his great
merits and achievements as an investigator.
DARWIN MEDAL.
Professor Giovanni Battista Grassi.
The Darwin Medal for 1896 is awarded to Professor Grassi, of
Rome (late of Catania), for his researches on the constitution of the
colonies of the Termites, or White Ants, and for his discoveries in
regard to the normal development of the Congers, Muraense, and
Common Eels from Leptocephalus larvas.
From a detailed examination of the nature and origin of the colo-
nies of the two species of Termites which occur in the neighbour-
hood of Catania, viz., Termes lucifugus and Callotermes flavicollis, he
was able to determine certain important facts which have a funda-
mental value in the explanation of the origin of these and similar
polymorphic colonies of insects, and are of first-rate significance in
the consideration of the question of the share which heredity plays in
the development of the remarkable instincts of " neuters," or arrested
males and females, in these colonies. Professor Grassi has, in facb,
shown that the food which is administered by the members of a
colony to the young larvae determines, at more than one stage of their
development, their transformation into kings or queens, or soldiers or
workers as the case may be, and the value of these researches is
increased by the observations which he has made on the instincts
of the different forms, showing that they do not in early life differ
from one another in this respect, and are all equally endowed with
the potentiality of the same instincts. These do not, however, all
become developed and cultivated in all alike, but become specialised,
as does the physical structure in the full-grown forms.
A very different piece of work, but having a no less important
bearing on the theory of organic evolution, is that on the Lepto-
cephali. These strange, colourless, transparent, thin-bodied creatures,
with blood destitute of red corpuscles, had been regarded as a special
family of fishes, but have been proved by Grassi's patient and long-
continued labours to be larval forms of the various Mureenoids. The
most astonishing case is that of the Common Eel, Anguilla vulgaris,
the development of which had been a mystery since the days of
Aristotle. It had been long known that large eels pass from rivers
into the sea at certain seasons, and that diminutive young eels, called
in this country Elvers, ascend the rivers in enormous numbers. But,
although the species is very widely distributed, no one in any country
had been able to discover how the elvers were produced. Grassi has
shown that, large as the eels are that pass into the sea, they are not
perfectly developed fish, but only attain maturity in the depths of the
31fi Anniversary Meeting.
ocean. There they in due time breed, and from their eggs are
hatched the young Leptocephali, which, after attaining a certain
size, cease to feed, and assume the very different form of the elver.
The possibility of establishing these remarkable facts depended on
the powerful oceanic currents that prevail about the Straits of
Messina, bringing up occasionally to the surface the inhabitants of
the depths of the sea. Grassi was thus able to obtain from, time
to time both adult eels with fully developed sexual organs and their
larval progeny, and he actually observed in an aquarium the develop-
ment of a Leptocephalus brevirostris into an elver.
Such highly meritorious contributions to evolution are fitly recog-
nised by the award ot the Darwin Medal.
The Statutes relating to the election of Council and Officers were
then read, and Professor Liversidge and Dr. Common having been,
with the consent of the Society, nominated Scrutators, the votes of
the Fellows present were taken, and the following were declared duly
elected as Council and Officers for the ensuing year : —
President.— Sir Joseph Lister, Bart., F.R.C.S., D.C.L.
Treasurer.— Sir John Evans, K.C.B., D.C.L., LL.D.
Secretaries — { Professor Michael Foster, M.A., M.D., D.C.L., LL.D,
1 Professor Arthur William Riicker, M.A., D.Sc.
Foreign Secretary. — Edward Frankland, D.C.L., LL.D.
Other Members of the Council.
Prof. William Grylls Adams, M.A. ; Professor Thomas Clifford
Allbutt, M.D.; Professor Robert Bellamy Clifton, M.A.; William
Turner Thiselton Dyer, C.M.G.; Prof. James Alfred Ewing, M.A. ;
Lazarus Fletcher, M.A. ; Walter Holbrook Gaskell, M.D. ; Prof.
Alfred George Greenhill, M.A. ; William Huggins, D.C.L. ; Prof.
Charles Lapworth, LL.D. ; Major Percy Alexander MacMahon, R.A. ;
Prof. Raphael Meldola, F.C.S. ; Prof. William Ramsay, Ph.D.; The
Lord Walsingham, M.A. ; Prof. Walter Frank Raphael Weldon,
M.A. ; Adml. William James Lloyd Wharton, C.B.
The thanks of the Society were given to the Scrutators.
Financial Statement.
317
318
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VOL. LX.
2 c
328
Account of Grants from the Donation Fund.
Professors Albert Heim, Gabriel Lippmann, G. Mittag-Leffler, and
G. Schiaparelli were, at the meeting on the 26th of November,
balloted for and elected Foreign Members of the Society.
The following Table shows the progress and present state of the
Society with respect to the number of Fellows : —
Nov. 30, 1895 . .
Since Elected
Since Compounded
Since Deceased . .
Withdrawn
Nov. 3P, 1896
Patron \
and Foreign.
Eoyal.
4!
+ 9
45
Corn-
pounders.
141
4- 2
4- 1
- 6
138
£4
yearly.
£3
yearly.
200
+ 13
- 1
- 3
209
Total.
498
-f 25
— 24
- 1
498
Account of Grants from the Donation Fund in 1895-96.
£ s. d.
Dr. Gamgee, in aid of his Researches 011 the Behaviour
of Haemoglobin, &c., toward Ultra-violet Rays 50 0 0
Coral Reef Committee, towards the Purchase of Dia-
monds for Boring a Coral Atoll in the Pacific Ocean .... 150 0 0
Dr. M. Foster, for Dr. W. Poole, Medical Officer of the
British Central African Protectorate, for the Purchase of
a Microscope to aid him in his Researches 21 211
Sir A. Geikie, in aid of Mr. Reid's Geological Borings at
Hoxne 30 0 0
Sir A. Geikie, to assist him in Excavations at Hitchin 50 0 0
Profs. Fleming and Dewar, in aid of their Researches on
the Diamagnetic qualities of Metals at Low Temperatures 50 0 0
Prof. Burdon Sanderson, in aid of his Investigations in
relation to Tuberculin 60 0 0
Dr. Yaughan Harley, in further aid of his Researches
on Absorption from the Alimentary Canal 25 0 0
Dr. J. G. Stoney, for Calculations of the Positions of
the November Meteors 15 0 0
Professor Sherrington, to aid him in his Researches on
the Nervous System 50 0 0
Marine Biological Association, towards the Purchase of
a Steam Yacht for trawling . , . , . , 100 0 0
£601 2 11
Professor Hermann's Theory of the Capillary Electrometer. 329
December 10, 1896.
Sir JOSEPH LISTER, Bart., F.R.C.S., D.C.L., President, in the
Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The President announced that he had appointed as Vice-Presi-
dents —
The Treasurer.
Professor Clifton.
Mr. Thiselton Dyer.
Dr. Huggins.
The following Papers were read : —
I. " On Professor Hermann's Theory of the Capillary Electro-
meter." By G-EORGE J. BURGH, M.A. Communicated by
Professor BURDON SANDERSON, F.R.S.
II. "An Attempt to determine the Adiabatic Relations of Ethyl
Oxide." By E. P. PERMAN, D.Sc., W. RAMSAY, Ph.D., F.R.S.,
and J. ROSE-INNES, M.A., B.Sc.
III. " The Chemical and Physiological Reactions of certain Synthe-
sised Proteid-like Substances. — Preliminary Communica-
tion." By JOHN W. PICKERING, D.Sc. (Lond.). Communi-
cated by Professor HALLIBURTON, P.R.S.
IY. " An Experimental Examination into the Growth of the
Blastoderm of the Chick." By RICHARD ASSHETON, M.A.
Communicated by ADAM SEDGWICK, F.R.S.
"On Professor Hermann's Theory of the Capillary Electro-
meter." By GEORGE J. BURGH, M.A. Communicated by
Professor BURDON SANDERSON, F.R.S. Received July 21,
—Read December 10, 1896.
I have received, by the courtesy of Professor Hermann, a copy of
his paper* on " Das Capillar-Electrometer und die Actionsstrome des
* * Archiv fur die Ges. Physiologic,' vol. 63, p. 44C.
2 C 2
330 Mr. G. J. Burch. On Professor Hermanns
Muskels," in which he discusses the analyses of certain electrometer
curves of muscle variation described by Professor Burdon Sanderson.*
His first statement demands an explanation on my part. He says,
" Bevor ich auf Sanderson's Versuche und Schliisse eingehe, mochte
ich zeigen dass der von Burch und von Einthoven aufgestellte, das
Capillar-Electrometer betreffende Satz, welcher der Construction zu
Grunde liegfc, auch aus meiner Theorie des Instruments unmittelbar
folgt, was beide Autoren, obwohl sie meine Arbeit erwahnen, nicht
bemerkt haben. Da beide ihren Satz empirisch gewonnen haben, so
kann derselbe als eine schone Bestiitigung meiner Theorie betrachtet
werden."
As a matter of fact, I did not know of Professor Hermann's paper
until after I had formed my own theory. In my second paperf on
the subject I mentioned that it had also been treated by him, " mainl}-
from a mathematical standpoint," and implied that, in my opinion,
his data were insufficient. I still think so, and cannot admit that
my experimental results prove the correctness of his views.
That a mathematical formula, based upon a certain hypothesis,
should agree with observed facts may be strong evidence in its
favour, but is not necessarily a proof of the soundness of the hypo-
thesis.
For instance, the equation
p — E . e~rt
may represent the discharge of a Ley den jar through a circuit of no
inductance, or the swing of a pendulum in treacle. That it happens
to be also the expression for the time-relations of the capillary
electrometer does not of itself imply that the same causes are at work
in all three cases, but simply that the forces concerned are so related
that the movement is dead-beat. Professor Hermann, starting from
Lippmann's polarisation theory, assumes the simplest conceivable
relation between the rate of polarisation and the acting P.D., namely,
that they are proportional to one another. Putting i = the intensity
of the current, and p = the amount of polarisation at the time t, he
gets
dp/dt = hi,
in which li is an instrumental constant.
Writing E for an electromotive force, which may be constant or
variable, and w for the resistance of the circuit, he arrives at the
differential equation
* ' Journal of Physiology,' vol. 18, p. 117.
f "Time-Relations of the Capillary Electrometer," 'Phil. Trans.,' A, vol. 183,
p. 81, 1892.
Theory of the Capillary Electrometer.
331
My position in relation to the problem was very different. I
wanted to make a capillary electrometer from the description given
in Lippmann's Theses. In order to get better results, I determined
by actual experiment what were the conditions of sensitiveness and
rapidity, and in doing this found out so much about the instrument
that the "einfachste denkbare Annahme," referred to by Hermann,
would not have commended itself to me.
My paper on the " Time-Relations of the Capillary Electrometer "
was a condensed account of a small portion of the work done by me.
For various reasons I did not then enter into my views as to the
theory of the instrument, and will confine myself here to a statement
of them, which must be regarded as preliminary.
Professor Hermann speaks of my theory having been empirically
obtained. I demur to that expression as open to misconstruction.
My working formula may rightly be called empirical, since it neglects
certain tsrms of the complete expression, which I have found to
neutralise each other in a suitably selected instrument, but my theory
of the time-relations of the capillary electrometer was founded upon
first principles and verified by experiments.
My starting point was the fundamental fact that in the capillary
electrometer a mechanical effect is produced by an electrical cause.
But there are several links between the cause and the effect, and
a strong probability that each of them involves a time-function.
They are shown in the following scheme : —
I.
II.
III.
IV.
A difference of
A change in the
Presumably giving
And does work in
potential (the
establishment of
which is delayed
constant of
capillarity at two
interfaces between
rise to polarisa-
tion at the afore-
said interfaces.
moving a column
of mercury, against
the force of gravity
by the (varying)
mercury and an
(with more or less
internal ohmic
electrolyte.
rapidity according
resistance of the
to the (varying)
electrometer)
amount of fluid
produces
friction in the
tube).
Poiseuille showed in 1846 that the flow of a liquid through a
capillary tube varies directly as the pressure. Of this I was not
aware till later, but it leads to precisely the same differential equa-
tion as that adopted by Hermann.
Writing Q for the quantity of electricity, C for the constant of
capillarity, P for polarisation, and W for the work done, the sym-
bolical expression of the problem is —
/(Q/, C,, Pt) = 0(W,).
332 Mr. G. J. Burch. On Professor Hermanns
Hermann has passed over C, and omitted to take W into account,
confining himself to the theoretical relation between Q* and P/.
But we know very little about polarisation, save in the case of
solid electrodes. The term polarisation, as frequently used, includes
two phenomena, which ought to be kept distinct, viz. : —
(a) That condition of the interface between two conductors, of
which one at least is an electrolyte, in which the molecules are under
a stress not greater than they are capable of supporting without
chemical change. .
(&) A deposit upon the surface of a solid, or in the contiguous
liquid, of the products of actual electrolysis.
If one of the conductors is a solid, the inevitable local differences
of condition or of composition enable actual electrolysis to take
place, even with a P.O. smaller than that proper to the chemical
change implied.
But if both conductors are liquid and perfectly pure, the stress is
so far equalised that no electrolysis is possible until the E.M.F.
reaches a certain value, more sharply defined in proportion as the
materials are pure.
I hold that with differences of potential which do not reach this
limit, the electromotive force is transmuted without electrolysis into
mechanical force, and manifests itself as kinetic energy, until by the
motion of the meniscus it becomes transformed into potential energy.
The locus of transformation from electrical to mechanical force must
clearly be the two interfaces mercury-acid and acid-mercury, and it
is upon these that the stress acts. The resistance is distributed along
the tube, and is partly electrical, but to a far larger extent mecha-
nical.
Is it reasonable, therefore, to assume that the sole cause of delay
is the " Polarisations-geschwindigkeit " of the meniscus ?
I believe that in the case of an interface between two liquids, the
rate of polarisation is to be measured in terms of the vibration-period
of a molecule, rather than in decimals of a second.
Actual electrolysis is another matter, and I hold that it does not
take place in a properly working electrometer. We do not assume
electrolysis when two pith balls repel each other after receiving a
charge, nor when a closed coil is slipped over a magnet. But the
coil cannot be got off again, nor can the balls fall together without
the generation somewhere of a current. , I cannot see why we should
assume electrolysis in the case of the capillary electrometer. The
marvellous rapidity of the action to which I have not yet found a
limit, is against it, as is also the fact that the substitution for the
acid, or the addition to it, of any substance which can be electrolysed
by a smaller electromotive force, reduces the range of potential dif-
ference for which it can be used.
Theory of the Capillary Electrometer. 333
The presence of even a trace of impurity is soon manifested by the
blocking of the capillary, and if this block is removed by electrolysis,
the instrument behaves for some time in an abnormal way. It shows
signs of a residual charge, like that of a Leyden jar, the mercury
rising again after the short-circuiting key is opened, instead of simply
ceasing to fall.
This I ascribe to polarisation of the kind met with between solids
and electrolytes, and to this the term "Pol arisations-geschwindig-
keit " would be applicable. But no good electrometer will show it,
except with electromotive forces greater than ought to be employed.
I have held from the first that the capillary electrometer acts by
transforming electrical into mechanical energy without any chemical
interchange, and that this is possible because at the interface
between two liquids which do not diffuse into each other the stress is
so evenly distributed that no one molecule can be strained to a degree
sufncient to detach any part of it until the stress is intense enough
to break down all similar molecules simultaneously.
But if by polarisation is meant this condition of the interface, then
I maintain that it must precede the movement, and must be deve-
loped with almost inconceivable rapidity.
In order to investigate the form of curve produced by recording
the motion of the meniscus when the electrometer is acted upon by
an electromotive force varying with the time according to some
known law, e.g., the pulsating or alternating current of a dynamo,
Professor Hermann puts his equation into a somewhat different form,
namely :
dpjdt+rp—rof(t) = 0,
where r and e are constants, and cf(t) = E is the electromotive force
represented as a function of the time.
But this is simply my own formula for the estimation of the
E.M.F. expressed as a differential equation.
For dp/dt is, in the polar curves taken with my machine, merely
the subnormal N", and rp is identical with &Ar, whence
dpjdt + rp rcf(t)
is identical with
K + *Ar - / («) volt,
which being interpreted signifies
fThesub-1 f A constant mul- 1 f The
I normal I , J tiple of the dis- I f A constant! I E.M.F. at
1 to the (^ 1 tan ce from the f " \ multiple of /] time t (m
curve. J zero-line. J I volts).
334 Mr. G. J. Burcli. On Professor Hermanns
Professor Hermann finds the complete primitive of this differential
equation, and then, introducing various values of r and the function
E = e/(0> draws, by a process which is indeed laborious, the curves
of the corresponding excursions. My own method gives a good deal
of the information so obtained in a much simpler manner.
Adopting the letters used by him, when/ vanishes we have
dp,'dt + rp = 0,
that is to say, whenever the E.M.F. falls to zero the reduced values
of the subnormal and the radius vector are equal, but of opposite sign,
and the curve, therefore, can never come back to the zero line under
the action of a current which pulsates but does not alternate (see
figs. 2 and 4 in Hermann's paper). When the meniscus crosses the zero
line, rp = 0, and dp/dt = ref(t), i.e., the impressed E.M.F. is then
directly proportional to the subnormal. This involves the further
fact that the crossing of the zero line by the meniscus must always
lag behind the change of sign of the E.M.F.
If dpjdt vanishes, as it does at the apex of a spike or the bottom of
a notch, the instantaneous value of the impressed E.M.F. is directly
proportional to the distance of the meniscus from zero.
The curves drawn by Professor Hermann are for the most part, so
far as the eye cau judge, similar to those obtainable under like condi-
tions with the capillary electrometer. I have photographed and
analysed many such, using rheotomes and dynamos of various kinds,
both alternating and direct current, as sources of E.M.F. I have
proposed, in a paper which has been in the publisher's hands since
last November, that this method should be used to determine the
characteristic current curves of dynamos.*
All the confusing influence of the lag vanishes when such curves
are analysed — there is no need to trouble about the equation to the
curve, since each several term of its differential equation at any given
point is found at once by my mode of analysis. But I must point
out that an error has crept into Professor Hermann's rendering of
the curve given in fig. 6 — or, rather, as it only pretends to be an
approximation, that it is not equally accurate throughout. The por-
tion c'd'f which corresponds to a diminishing negative (below zero)
potential is represented as rising with 'increasing velocity instead of
falling more slowly, as it should do. Yet, when this negative poten-
tial ceases, the curve commences to fall from d' to e' along the
logarithmic curve of discharge. This is impossible. When e f(t) is
negative, the algebraic sum of dp/dt and rp must be negative also if
the fundamental equation holds good. Probably the straight line cd
has been placed too far to the right.
* ' The Electrician/ July 17, 1896, et sey.
Theory of the Capillary Electrometer. 335
Professor Hermann questions the accuracy of my method of
analysis when applied to steep curves.
My answer is that I do not employ it in such cases, preferring to
take photographs of sudden changes upon plates moving with suffi-
cient rapidity to suitably develope the curves.
Thus in Professor Burdon Sanderson's paper,* figs. 1, 2, 3, and 4,
on Plate 1, and figs. 3, 4, and 5, on Plate 3, were intended to show
within the limits of a page the entire course of certain phenomena.
I did not analyse them, but simply measured the times of the maxima
and minima. The remaining curves, viz., figs. 5 and 6, Plate 1, figs.
1 — 7 on Plate 2, and figs. 1 and 2 on Plate 3, are all suitable for
analysis, with the exception of the first phase of fig. 1, which is
almost too steep. I have done some thirty or forty of this kind.
As regards the further criticisms, so far as the physical interpre-
tation of the curves is concerned, I can only say that cases did occur
in which the maximum E.M.F. of the second (positive) phase
exceeded the maximum E.M.F. of the first (negative) phase of the
same response. With respect to curves, like those in figs. 3 and 4,
Plate II, the part referred to by Professor Burdon Sanderson as
the " hump," is not merely the curve of discharge. The actual
negatives which I measured show a rise of the meniscus after its
rapid downward movement has ceased, and while it is still above the
zero line, and a similar rise is plainly visible to the eye after every
one of the "spikes " in figs. 1, 2, and 4, Plate 1, which were photo-
graphed with the machine moving more slowly.
It is impossible for the mercury, under these conditions, after
approaching the zero line, to recede from, without crossing it, except
under the influence of a negative Acting P.D. That is to say, the
Impressed E.M.F. must be of the same sign as the charge already
in the instrument, but must be of higher potential difference. In
some negatives this second rise in followed by a descent more rapid
than that of the curve of discharge, and therefore indicating a small
positive Acting P.D. I first noticed and called attention to it in
connection with the curves illustrating my paperf on the " Time
Kelations of the Capillary Electrometer," but refrained from discus-
sing its physiological significance.
* ' Journal of Physiology/ vol. 18, p. 117.
f < Phil. Trans.,' A, vol. 183, p. 104*
336 Attempt to determine the Adiabatic Relations of Ethyl Oxide.
" An Attempt to determine the Adiabatic Relations of Ethyl
Oxide." By E. P. PERMAN, D.Sc., W. RAMSAY, Ph.D.
F.R.S., and J. ROSE-INNES, M.A., B.Sc. Received November
6,— Read December 10, 1896.
(Abstract.)
The wave-length of sound in gaseous and in liquid ethyl oxide
(sulphuric ether) has been determined by the two first-mentioned of the
authors, by means of Kundt's method, between limits of temperature
ranging from 100° C. to 200° C., and of pressure ranging from
4000 mm. to 31,000 mm. of mercury, and of volume ranging from
2'6 c.c. per gram to 71 c.c. per gram. Making use of the same appa-
ratus throughout, the results obtained are to be regarded as com-
parative, and, by careful determination of the pitch of the tone
transmitted through the gas, it is probable they are approximately
absolute.
The sections of the complete memoir deal with (I) a description of
the apparatus employed, (II) the method of ascertaining the weights
of ether used in each series of experiments, (III) determinations of
the frequency of the vibrating rod, (IV) the calculations of th£
adiabatic elasticity and tables of the experimental results, and (Y) a
mathematical discussion of the results. The last section is due to
Mr. Rose-Innes.
As the theoretical results are of interest, a brief outline of them
may be given here.
It will be remembered that one of the authors, in conjunction with
Dr. Sydney Young, showed that for ether, and for some other liquids,
a linear relation subsists between pressure and temperature, volume
being kept constant, so that
p = bT — a.
It has been found that a similar relation obtains between adiabatic
elasticity and temperature, volume, as before, being kept constant ;
so that, within limits of experimental error, where E stands for
adiabatic elasticity,
E = jT-A,
g and h being functions of the volume only. Between these two
equations, we may eliminate T, and so express E as a linear function
of p, volume being kept constant. The coefficient of p in such an
equation would be g/b, and this fraction, on being calculated from
the data 'available, proves to be nearly constant. For working pur-
poses it is assumed that g/b may be treated as strictly constant, and
Reactions of certain Synthesised Proteid-like Substances. 337
it is shown that this assumption does not introduce any serious error
within the limits of volume considered. We tnen find it possible to
integrate the resulting differential equation, and the complete primi-
tive enables us to draw a set of adiabatic curves. We believe that
this is the first time adiabatic curves have been obtained for any
substance except perfect gases.
A mathematical discussion is added as to what extent the equations
E = gT-h
and yjb = constant,
can be considered as strictly true, and not merely approximate.
The experimental results for liquid ether form an appendix to the
paper.
"The Chemical and Physiological Reactions of certain
Synthesised Proteid-like Substances. Preliminary Com-
munication." By JOHN W. PICKERING, D.Sc. (Lond.).
Communicated by Professor HALLIBURTON, F.R.S. Re-
ceived November 10, — Read December 10, 1896.
The experiments of Professor Grimaux,* made more than ten
years ago, have until recently attracted but little attention amongst
English physiologists, although that investigator has synthesised a
series of colloidal substances which, in their chemical characteristics,
show striking similarities to proteids.
Working alone, and in collaboration with Professor Halliburton, If
have shown that three of the substances synthesised, viz., the
" Colloids amidobenzoic A and B," formed by the interaction of
phosphorus pentachloride and meta-amido-benzoic acid at 125° C.,
according to the details described in Grimaux's papers, and the
" colloide aspartique " formed by the passage of a current of dry
gaseous ammonia over solid aspartic anhydride heated to 125° C., not
only give the leading chemical reactions of proteids, but when intra-
venously injected into dogs, cats, or pigmented rabbits, cause
extensive intravascular coagulation of the blood, in a manner indis-
tinguishable from the physiological action of nucleo-proteids. When
injected into the veins of albino rabbits or into the vascular system
* G-rimaux, ' Comptes Kendus,' vol. 93, p. 771, 1881 ; ibid., vol, 98, p. 105, 1884 ;
ibid., vol. 88, p. 1434 and p. 1578.
t Pickering, ' Journ. Pliysiol.,' vol. 14, p. 341, 1893 ; ' Comptes Eendus,' vol. 120,
p. 1348, 1895; 'Physiol. Soc. Proc.,' Feb. 1.6, 1895 ('Journ. Physiol.,' vol. 17) ;
4 Journ. Physiol.,' vol. 18, p. 54, 1895; Hid., vol. 20, p. 171, 1896; ibid., vol. 20,
p. 310 ; Halliburton and Pickering, ' Journ. Physiol.,' vol. 18, p. 285, 1895.
338 Dr. J. W, Pickering. The Chemical and Physiological
of the Norway hare (^Lepus variabilis), during" its albino condition,
these substances fail to induce intravascular coagulation of the blood,
although they hasten the coagulation of the blood when drawn from
the carotids, in a precisely similar manner to nucleo-proteids.
Taking these facts as the basis of my investigations, I have en-
deavoured to synthesise substances which will approach more nearly
in their chemical and physiological reactions to proteids than those
briefly described above ; and to further investigate the properties of
Grimaux's colloids.
I. General Description of Experiments.
I have up to the present synthesised seven different colloidal sub-
stances, by the interaction of either phosphorus pentachloride or
pentoxide on certain well-known derivatives of proteids, and the
details of their preparation, physical properties, chemical and physio-
logical reactions are described below.
Colloid a. — Prepared by the interaction of equal parts of meta-
amido-benzoic acid, biuret, and three times its weight of phosphorus
pentoxide at 125° C. in a sealed tube. The best results are obtained
by continuing the heating for about six hours, although a similar
substance is obtained by heating for half an hour at 130° C. The
product of the reaction is a pinkish-grey friable powder, which is
insoluble in cold water, and almost insoluble in boiling water.
This substance should be repeatedly washed until all traces of
phosphoric acid a.re removed. When heated with Millon's reagent
it fails to give the reaction characteristic of tyrosine and proteids ;
it also does not give the well-known colour reactions with the
salts of copper, nickel, cobalt, and caustic potash. It gives the
typical blue reaction associated with the name of Frohde* when
heated with sulphuric and molybdic acids, as well as the xantho-
proteic reaction.
If the amount of biuret exceeds the amount of meta-amido-benzoic
acid, then the excess of biuret left over gives its typical colour
reaction with copper sulphate ancl potash.
The pinkish-grey powder, obtained by the reaction described
above, should be dissolved in ammonium hydrate, and the resulting
solution evaporated down at the temperature of the atmosphere in
vacuo, when the resulting product appears as a number of translucent
yellowish plates, which are tasteless and inodorous, and closely
resemble in appearance both Grimaux's " collo'ides amido-benzoique
and aspartique " and dried serum-albumen. These plates are with
difficulty soluble in cold water, but readily pass into solution on
warming. The solution obtained does not coagulate on heating, but
* Frohde, ' Annalen der Chemie,' vol. 145, p. 376.
Reactions of certain Sunthesised Proteid-like Substances. 339
if a trace of a soluble salt of either barium, strontium, calcium,
magnesium, or sodium be added, a pronounced coagulum is obtained
011 heating. This point will be returned to you in a subsequent-
section, but the similarity to dialysed serum-albumen may be pointed
out, as that substance is stated not to coagulate when heated.*
The solution does not coagulate spontaneously on standing,
neither will the addition of "fibrin ferment (i.e., a nucleoproteidf)
induce coagulation. It gives a typical xanthoproteic reaction, a
violet with copper sulphate and potash, a dark heliotrope-purple
with cobalt sulphate and potash, and a faint yellow with nickel
sulphate and potash. It also gives Frdhde's sulpho-molybdic reaction ;
I may, however, remark that I found that several substances chemi-
cally allied to proteids yield this reaction, which is therefore not
diagnostic of proteids alone. An alcoholic solution of alloxan gives
with the solid plates a brilliant red coloration (Krasser'sJ reaction)
similar to that produced with plates of serum-albumen. Negative
results were obtained with the reactions associated with the names of
Liebermann,§ Adamkiewicz,|| and Millon.^f
The solution is neutral and laevorotatory (aD = —52), and if treated
with pepsin and a O2 per cent, hydrochloric acid, or by an alkaline
solution of trypsin, for several days at 38° C. it does not peptonise.
Qualitative analysis shows that this substance does not contain
phosphorus in its molecule.
It is precipitated from solution by mercuric chloride, silver nitrate,
and lead acetate. These precipitates yield the same colour reactions
as the original substance.
The precipitate formed by the addition of lead acetate, like that
obtained by the addition of this substance to a proteid solution,
redissolves on the passage of a current of sulphuretted hydrogen
through the solution in which it is suspended, and judging by
chemical tests alone, the nature of the substance is unchanged by the
processes of precipitation and redissolving. Its physiological action
is, however, markedly changed, as will be shown later on.
The original solution is readily precipitated by trichloracetic,
phosphotungstic, phosphomolybdic acids, and by acetic acid and
potassium ferrocyanide, as well as by salicylsulphonic acid ; the pre-
cipitate formed by this last substance is coagulated by heating in a
manner similar to the coagulation produced by heating the pre-
cipitate resulting from the addition of this substance to a proteid
* Schmidt and Aronstein, ' Pfluger's Arcliiv,' vol. 8, p. 75, 1874.
f Vide Halliburton, ' Journ. Physiol.,' vol. 18, p. 306, 1895.
J Krasser, ' Monat. i'iir Chem.,' vol. 7, p. 673 ; ' Muly's Jahresb.,' vol. 16, p. 1.
§ Liebermann, ' Maly's Jahres.,' vol. 18, p. 8.
|| Adamkiewicz, 'Ber. d. deut. Chem. Gresell.,' vol. 8, p. 761.
If Millon, ' Comptes Kendus,' vol. 28, p. 40.
340 Dr. J. W. Pickering. The Chemical and Physiological
solution. I may here mention that salicylsulphonic acid does not
precipitate disintegration products of proteids like leucine, tyrosine,
xanthine, or hypoxanthine.
All the precipitates cited above give the colour reactions charac-
teristic of the original substance.
If the original solution is saturated with either magnesium sul-
phate, ammonium sulphate, or sodium, chloride, the whole of the
colloid rises to the surface of the liquid, and may be skimmed off.
On placing this scum in an excess of distilled water, it rapidly
redissolves, forming a pale yellow opalescent solution, which gives
all the chemical reactions characteristic of the original substance.
If the amount of neutral salt be insufficient to produce precipita-
tion, the passage through the liquid of a current of carbon dioxide
or of sulphur dioxide will effect the same result. Neither of these
gases will, however, cause precipitation in the entire absence of salts.
The following experiments illustrate the results produced by the
intravenous injection of this substance into dogs, rabbits, and cats.
The procedure adopted was identical with that described in the
previous papers published by Professor Halliburton and myself,* on
the intravascular injection of Grimaux's colloids. In all cases the
animal was ana3sthetised by a mixture of chloroform and ether, an
excess of the latter substance being used when the subjects were dogs.
'Experiment 1. — Fox terrier (weight 27 Ibs. 10 oz.) ; 25 c.c. of a
0*75 per cent, solution of the colloid a was injected, and proved
fatal. Pronounced exophthalmos and dilatation of the pupils, and
typical stretching movements were observed.
Post-mortem examination made immediately after death revealed
pronounced clots in the jugular vein, inferior vena cava, and portal
vein, and a slight clot in the left ventricle and in the pulmonary
artery.
Experiment 2. — Large black cat (weight 9 Ibs. 6 oz.) ; 40 c.c. of the
colloid proved fatal, with similar symptoms as above. Immediate
post-mortem examination showed pronounced clots in the left ventricle,
right auricle, inferior vena cava, portal, and jugular veins. The
remainder of the blood was fluid, but coagulated very rapidly after
withdrawal.
Experiment 3. — Black rabbit ; 38 c.c. of the same substance pro-
duced a similar result.
Experiment 4. — Albino rabbit ; 42 c.c. proved fatal. Death was
accompanied by pronounced exophthalmos and dilatation of the
pupils and stretching movements of the limbs. Post-mortem exami-
nation showed the blood throughout the vessels to be fluid. It, how-
ever, rapidly coagulated after withdrawal from the vessels, and the
coagulability of samples of the blood taken from, the carotids during
• Op. cit.
Reactions of certain Synt/iesised Proteid-li/se Substances. 341
the injection of the colloid was also hastened ; thus after 20 c.c. of
the colloid had been injected, the time of complete coagulation of
blood withdrawn from the carotids was hastened by 2 minutes,
after 30 c.c. by 3f minutes, and after 35 c.c. by 4 minutes.
It will be evident that the results recorded above are similar to, if not
indistinguishable from, those produced by the intravenous injection of a
nucleoproteid.
When slowly introduced into the circulation of dogs, and to a
much lesser degree of rabbits, in minute quantities, the effect pro-
duced on the coagulability of the blood is the converse of that
resulting from the introduction of larger quantities. This effect is
more pronounced than that obtained by the intravenous injection of
Grimaux's colloids, and more resembles Wooldridge's* " negative
phase," which is characteristic of a nucleoproteid, but is not so pro-
nounced as the result obtained with that substance.
This result is illustrated by the following experiment : —
Experiment 5. — Large black mongrel. Anaesthetic, ether and
morphia (weight, 60 Ibs.) ; 1 c.c. of a 0'025 per cent, solution colloid a
was injected very slowly, the injection being distributed over half an
hour, at the end of which time the retardation of the time of coagu-
lation of blood withdrawn from the animal's carotid was found to be
8 minutes 30 seconds. A second dose of 1 c.c. of the same solution
injected and distributed over 20 minutes caused a further retardation
in the time of coagulation of the carotid blood of 2 minutes ; but
a third injection distributed over a similar period of time hastened
the coagulability of the blood that had been previously retarded, so
that the retardation, as compared with the time of coagulation before
the injection of the colloid, was only 1 minute 30 seconds. After a
still further injection of the colloid, the blood coagulated more
rapidly than in the normal condition, and finally, when the dose was
pushed, intravascular coagulation of the animal's blood occurred,
and death resulted.
If the colloid is separated from the solution by saturation with
magnesium sulphate, sodium chloride, or ammonium sulphate, as before
described, and the scum redissolved in distilled water, the opalescent
solution obtained will, when intravenously injected into pigmented
rabbits, produce typical intravascular coagulation. Repetition of the
process of precipitation and redissolving however, destroys the
physiological activity in a manner similar to the result produced
with both nucleo-proteids and Grimaux's synthesised colloids.
If the solution formed by the passage of a stream of sulphuretted
hydrogen over the precipitate formed by the addition of lead acetate
to the colloid is injected intravenously into pigmented rabbits or
* Wooldridge, <Du Bois-Keymond's Archir,' 1886, p. 397 j 'Proc. Eoj. Soc.,'
vol. 40, p. 134, 1886.
342 Dr. J. W. Pickering. The Chemical and Physiological
dogs, it is found not to induce intravascular coagulation, although its
chemical and physical characteristics are apparently unchanged.
This result shows that the chemica] reactions used for " testing "
proteids are not sufficiently delicate to indicate the chemical changes
which are demonstrable by physiological methods. The following
experiment illustrates this result : —
Experiment 6. — Black rabbit (weight 7 Ibs. 9 oz=?.) ; anaesthetic,
chloroform and ether ; 120 c.c. of redissolved solution injected pro-
duced dyspnoea, exophthalmos, dilatation of pupils. A further injec-
tion of 10 c.c. of this substance was immediately fatal. Post-mortem
examination failed to reveal any clots in the animal's vessels. Blood
withdrawn from the carotids during the injection showed only one
minute's decrease in the time taken to complete coagulation.
Experiment 7. — In another experiment, where minute quantities of
this substance were very slowly injected, there was no retardation of
the time of coagulation, like that produced by the original substance
or by a nucleo-proteid.
Colloid p. — This substance is formed by heating together tyrosine.
biuret, and phosphorus pentachloride in the ratio of equal weights of
the two former substances, with twice the weight of the latter, for six
hours at 125° to 130° C. in sealed tubes. The product of this reaction
is a grey powder insoluble in cold water, and very sparingly soluble
on heating. This substance gives the xantho-proteic and Frohde's
reaction, but fails to give typical colour reactions with the other re-
agents commonly used in testing proteids. It should be repeatedly
washed until all traces of the contaminating phosphoric acid are
removed, and then dried in vacua at about 30° C. It readily dis-
solves in concentrated ammonium hydrate, and the solution is
opalescent and laevorotatory (aD = —48), and in appearance indis-
tinguishable from that of the other colloids produced. It gives the
following distinctive reactions as classified in the annexed table, but
does not digest when subjected to the action of either pepsin and
0'2 per cent, hydrochloric acid for three days at 38° C., or of an
alkaline solution of trypsin, kept at the same temperature for a
similar time. It yields the following distinctive reactions: —
Colloid 3.
CuSO4
KHO.
CoSO4
KHO.
NiSO4
KHO.
H2SO4 and
molybdic
acid.
Millon's
reagent.
HXOg and
JSH4OH
(heating).
Sal icy 1
sulphonic
acid.
1
Violet-
Heliotrope
Faint
Dark blue
Dark red
Orange
Precipitate
coloured
solution.
purple-
coloured
yellow-
coloured
precipitate.
precipitate.
precipitate.
which
coagulates
solution.
solution.
on heating.
Reactions of certain Synthesized Proteid-like Substances. 343
It gives negative results with the reactions of Liebermann and
Adamkiewicz, but gives the typical red coloration when .the solid
plates are heated with an alcoholic solution of alloxan (Krasser's
reaction). It is separated from solution by neutral salts in a
manner similar to the colloid a and Grimaux's colloids. The scum
also redissolves in distilled water giving an opalescent straw-
coloured solution. It is precipitated by silver nitrate, lead acetate,
and mercuric chloride, as well as by phosphotungstic, phospho-
molybdic, and trichloracetic acids, and by acetic acid and potassium
ferrocyanide.
In the entire absence of salts it is not coagulated on boiling, but,
on the addition of a trace of a soluble salt of either sodium, magne-
sium, barium, strontium, or calcium, a coagulum is obtained on
heating to 74° C.
The fractional heat coagulation of this substance will be dealt with
in a subsequent section.
The effect produced by the intravascular injection of various
quantities of this body is illustrated by the following expeiiment: —
Experiment 8. — Brown mongrel (weight 27 Ibs. 7 oz.) ; anaesthe-
tised with ether and morphia. The jugular vein on the one side,
and the carotid artery on the other, were exposed, and cannula3
inserted into them. The colloid y3 was injected into the jugular vein,
and samples of blood withdrawn from the artery. The following
table shows the rate of clotting of the various samples : —
(1) Before injection of the colloid, the blood clotted in 10 minutes
30 seconds.
(2) 5 c.c. of 075 per cent, solution of colloid dissolved in 075 per
cent, saline injected. A firm clot formed in 17 minutes
8 seconds.
(3) 10 c.c. more injected. Loose clot in 22 minutes.
(4) 10 c.c. more injected. Firm clot in 31 minutes.
(5) 10 c.c. more injected. Firm clot in 13 minutes.
(6) After interval of 5 minutes a second sample of carotid blood
formed a firm clot in 7 minutes 30 seconds.
(7) 7 c.c. more injected. Firm clot in 7 minutes 30 seconds.
(8) 10 c.c. more injected. Firm clot in 6 minutes.
(9) 15 c.c. more injected. Firm clot in 3 minutes.
(10) 10 c.c. more injected and proved fatal.
Immediate post-mortem examination revealed loose clots in vena
cava inferior, and jugular vein, and pronounced clots in portal vein,
and right ventricle.
This experiment shows the " negative phase " after injection of small
quantities of the colloid ft, and the typical hastening of the coagulabilit ,j
of the blood withdrawn from the carotid after the intravenous injection of
VOI.K. 20
344 Dr. J. W. Pickering. The Chemical and Physiological
a larger dose, and finally the coagulation of the intravascular blood when
the dose is again increased.
Colloid 7. — The colloid 7 is formed by heating together at 130° C. in
sealed tubes, for three hours equal weights of alloxan and metamido-
benzoic acid, with twice their weight of phosphorus pentoxide. The
product of the reaction is a white powder, very slightly soluble in
cold water, and sparing soluble in warm water. It should be washed
in ice-cold water till the excess of phosphoric acid is removed, and
the remaining substance dissolved in concentrated ammonia, The
resulting solution is opalescent and straw-coloured, and should be
evaporated down at the temperature of the laboratory in vacuo, when
a number of translucent, yellowish plates, closely resembling the
previously described colloids are formed. These plates are soluble
in warm water, and the solution is pale straw-coloured, opalescent,
and Isevorotatory (aD = — 41) and shows the following reactions: —
Colloid 7.
HNOH
NH4OH.
(heating).
Millon's
reagent.
Fronde's
reaction.
CuSO4 and
KHO.
NiSO4 and
KHO.
CoSO4 and
KHO.
Salieyl-
sulphonic
acid.
Yellow
Dirty
Blue pre-
Violet
Very faint
Dark
No pre-
solution.
brown
cipitate.
solution.
yellow
brown
cipitate.
ppt.
solution.
solution.
It is separated from solution by saturation with either magnesium
sulphate, sodium sulphate, sodium chloride, or ammonium sulphate,
the colloid rising to the surface of the liquid as a white scum, which
redissolves, forming an opalescent solution when thrown into dis-
tilled water. It is precipitated by silver nitrate, lead acetate, and
mercuric chloride. If the precipitate formed by the addition of lead
acetate is suspended in distilled water, and a current of sulphuretted
hydrogen is passed through the liquid, the precipitated colloid again
passes into solution.
When heated in the presence of a trace of a neutral salt, fractional
heat-coagulation is obtained, which will be detailed in a subsequent
section.
If the colloid 7 is injected into the circulation of dogs or pigmented
rabbits, even in large quantities, it does not produce intravascular
coagulation, although it somewhat hastens the coagulability of blood
withdrawn from the carotid.
The colloid 7, although yielding many of the chemical reactions that
have been used as distinctive tests for proteids, and also behaving in a
very similar manner to the previously described proteid-like colloids, does
Reactions of certain Synthesized Proteid-like Substances. 345
not, like them, produce intravascular coagulation when intravenously
injected into pigmented rabbits. Neither will the colloid 7 when intro-
duced into the circulation of dogs, very slowly and in minute quan-
tities, produce a retardation of the coagulation of blood withdrawn
from the carotids.
Colloid c. — The colloid B is formed by heating at 125° C. in sealed
tubes for three hours, equal weights of para-amidobenzoic acid and
phosphorus pentachloride. The resulting product, a grey friable
powder, insoluble in cold water, was, after washing to remove the
contaminating phosphoric acid, dissolved in concentrated ammonia,
and evaporated down at a low temperature in vacuo. The resulting
substance appears as a number of translucent yellowish plates,
apparently similar to those previously described. They are soluble
in warm water, forming an opalescent straw-coloured solution, which
is loevorotatory («D = —42). This solution gives the xantho-proteic
and Frohde's reaction, but fails to give the typical colour reactions of
proteid-like substances with salts of copper, cobalt, or nickel and
caustic potash ; neither does it give the reactions of Millon, Lieber-
manii, or Adamkiewicz. It is not precipitated by salicylsulphonic
acid, but it is precipitated by salts of the heavy metals. Neutral
salts separate it from solution like the preceding substances. When
freed from salts, it does not coagulate on heating, but if a trace of
sodium chloride or of another neutral salt be present, it coagulates
on heating, to 75° C. When intravenously injected into pigmented
rabbits, it fails to produce intravascular coagulation, neither does it
hasten the coagulability of blood withdrawn from the carotids. It
fails to induce a " negative phase " in the coagulation of dogs' blood.
This series of results lends additional support to the view that the
coagulation of the blood resulting from intravenous injection of the
colloid, is due to the interaction of the colloid with the constituents of
the plasma, and not to the heavy nature of colloid molecule.
Colloid e. — The colloid c is prepared by heating together equal
weights of tyrosine and xan thine with twice their weight of phos-
phorus pentachloride at 125° C. for three hours. The product of
the reaction is a yellowish powder slightly soluble in warm water.
After repeated washing in cold water, it is dissolved in concentrated
ammonia, and the resulting solution evaporated down in vacuo at a
low temperature. The resulting substance consists of a number of
translucent yellowish plates like those previously described. It is
readily soluble in warm water, forming a yellowish opalescent solu-
tion, which is laevorotatory (aD = —38).
This solution gives a typical red when heated with Millon's reagent,
which is not due to an excess of tyrosine, since the intermediate pro-
duct in the preparation of the substance fails to give this reaction.
It does not give any other of the distinctive proteid colour reactions,
2 D 2
346 Dr. J. \Y. Pickering. The Chemical and Physiological
but is precipitated by salicylsulphonic acid, and the precipitate coagu-
lates on heating. It behaves with neutral salts and salts of the heavy
metals similarly to the previously described substances. It does not
cause intravasculiir coagulation of the blood when intravenously
injected into dogs or pigmented rabbits, neither will the very slow
injection of minute quantities into the circulation of dogs induce a
"negative phase." It does not induce coagulation when added to
1 per cent, sodium carbonate plasma.
Colloid £ is prepared in a similar manner to the colloid e, hypo-
xanthine being substituted for xanthine. It has a similar appear-
ance to the colloid e, is leevorotatory (aD = —40), gives Milloii's
reaction, and negative results with the other tests characteristic of
proteids.
It also behaves with neutral salts and salts of the heavy metals in
a similar manner to the previously described substances. When
intravenously injected into the circulation of dogs or pigmented
rabbits, it fails to induce intravascular coagulation, neither will it
cause coagulation when added to extravascular 1 per cent, sodium
carbonate plasma.
Colloid i). — The colloid if is prepared by the interaction of tyrosine
and phosphorus pentoxide for three hours at 130° C. in sealed
tubes. The product of this reaction is a pinkish friable powder,
sparingly soluble in cold water and soluble on boiling. This sub-
stance does not yield Millon's reaction. After washing in cold water
to remove the contaminating phosphoric acid, the powder is dissolved
in concentrated ammonia, and a straw-coloured opalescent solution is
obtained. This is evaporated down in vacuo, and the resulting sub-
stance appears as a number of plates, similar in appearance to those
of the previously described colloids, and which are soluble in warm
water, giving an opalescent solution. This solution is precipitated by
salicylsulphonic acid and the precipitate coagulates on heating. It is
also1 precipitated by salts of the heavy metals, and separated from
solution by neutral salts. It does not yield any of the distinctive
colour reactions of proteids, and fails to produce intravascular coagu-
lation when intravenously injected into rabbits.
II. The Fractional Heat Coagulation of Synthesised Colloids.
The method of differentiating the members of a mixture of proteids
by fractional heat coagulation was introduced by Halliburton,* and
employed by him more especially in the examination of the proteids
of serum. This method was subsequently used by Coriii and Berardf
in separating the albumins of the white of egg, and by Chittenden
* Halliburton, ' Journ. Physiol.,' TO!. 5, p. 159.
f Corin and Berard, ' Bui. de 1'Acad. Boy. de Belgique,' vol. 15, 4, 188S.
Reactions of certain Synthesized Proteid-Uke Substances. 347
and Osborne* in studying the proteids of maize. The method was
rendered more accurate by Hewlett,f who substituted a bath of cod-
liver oil for the water bath usually employed as the heating medium,
and exhaustively dealt with the adverse criticisms made by Haycraft
and Duggan.J
I have applied this method, using an oil bath, in the examination
of the proteid like colloids synthesised by Professor Grimaux and
myself. As pointed out in a previous section, in the entire absence
of salts these substances do not coagulate, even when boiled. For
the sake of comparison the following experiments were performed,
so as to satisfy the following conditions :— (a) A 2 per cent, solution
of the substance under examination was always used, (b) The
diluent fluid always consisted of a 0*75 per cent, solution of sodium
chloride, (c) In each experiment 10 c.c of the fluid under examina-
tion was used, and the test-tubes were of uniform internal diameter.
By this means the mass to be heated remained constant, (d) The
thermometer was placed in the middle of the test-tube containing the
fluid under examination.
The colloid A (" colloide amidobenzoique " of Grimanx) shows a
coagulation temperature of 70° to 71° C.
The colloid B (of Grimaux) which is prepared from the same
reagents as the colloid A, but the temperature at which the reaction
of synthesis is conducted is allowed to rise to 130° C., shows on
heating one faint appearance of flocculi at 56° to 58° C., and a
second more pronounced coagulum at 70° to 72° C.
The colloid C (" colloide aspartique " of Grimaux) on fractional
heating shows three distinct sets of flocculi, appearing respectively
at 58°, 67°, and 73'1° to 76'4° C.
The colloid a, if care has been taken to keep the temperature of
preparation constant at 125° C., shows, on heating, only one coagu-
lum at 70'6° ; if, however, in the preparation of this colloid the tem-
perature of synthesis is allowed to rise, a second colloid coagulating
at 42° C. is often but not always formed.
The colloid /3, even when the temperature of the synthesis has
been kept constant at 130° C., shows, on heating, three constituents
coagulating at 47° C., 56° C., and 74° C.
The colloid 7 apparently only has one temperature of heat coagu-
lation, viz., 75° C.
The colloid b coagulates at 75° C.
The colloid e coagulates only at 47° C.
The colloid £ coagulates at 48° and 59° C.
* Chittenden and Osborne, ' Amer. Chem. Jo urn.' vol. 13, 7 and 8j vol. 14, 1.
t Hewlett, ' Journ. Physiol.,' vol. 13, p. 493, 1892.
J Haycraft and Duggan, * Brit. Med. Journ.,' 1890, vol. 1, p. 167; ' Edin. Roy.
Soc. Proc.,' vol. 16, p. 361, 1888-9.
#43 Reactions of certain Synthesised Proteid-like Substances.
The colloid // coagulates only at -52° C.
Adopting the conclusion of Halliburton that the precipitates ob-
tained by the fractional heat coagulation of a proteid substance,
correspond with various constituents of that substance, we may
possibly conclude that those synthesised colloids which yield frac-
tional heat-coagula are mixtures of different colloidal substances.
Thus the colloid B would consist of two substances which might
be designated Bx and B2, and the colloid ft of three substances,
designated colloids /3i, /32, and /33 respectively, and the colloid £ of
two substances, ^ and £2. I have endeavoured to ascertain in the
cases of the colloids B! and B3 and of the colloids /31? y32, and fa
whether each of these substances will equally induce intravascular
coagulation of the blood, when intravenously injected into pigmented
rabbits and dogs.
The method of procedure adopted was briefly as follows : — The
activity of a solution of the colloid was tested by a control experi-
ment. One of the constituents was removed by fractional heat-
coagulation and the effect, if any, produced by the intravascnlar in-
jection of the remaining colloid in solution wras tested.* The follow-
ing is the record of some of the results obtained : —
Colloid B2 after a removal of colloid Bt will, if intravenously
injected, induce intravascular coagulation in pigmented rabbits, and
if slowly injected in minute doses a "negative phase " in dogs.
Colloids $8 and /33 will still, after the removal of colloid j3h induce
intravascular coagulation in pigmented rabbits, although a much
larger dose is required after the removal of (3i and /32 than if the
mixture of the three substances is injected, if only fa is removed the
activity of the mixture is not impaired. From this I conclude that
fa and /33 are the active constituents of the colloid mixture I have
designated as the colloid /3. There is apparently no difference in the
tendency to induce a "negative phase" in dog's blood after the
removal of fii and /32 from the solution.
III. Other Properties of the Synthesised Colloids.
The influence of these substances on red and white blood cor-
puscles, and on extravascular 1 per cent, sodium carbonate plasma
will be described in a subsequent paper.
IV. Concluding Remarks.
It is evident from the observations recorded in the preceding
pages, that if certain derivatives of proteids, and other substances of
* The solution after removal of one of its constituents by fractional heat-
coaguiation, was evaporated down in vacuo until it had the same specific gravity as
the original solution.
On the Growth of the Blastoderm of the Chick. 341)
allied chemical constitution are heated together in sealed tubes with
an excess of either phosphorus pentachloride or pentoxide, a series of
colloidal substances are formed which, when freed from the con-
taminating phosphoric acid, and dissolved in concentrated ammonia,
give opalescent solutions that, on evaporating down in vacuo, yield
substances closely resembling in physical, chemical, and physiolo-
gical properties certain proteids.
These colloidal substances, although they differ from one another
in minor details, are usually distinguished by the following charac-
teristics : —
1. They are soluble in warm water, forming opalescent Isevorota-
tory solutions.
2. The resulting solutions yield the principal colour reactions
hitherto deemed diagnostic of proteids.
3. In the absence of salts, solutions of these colloids do not coagu-
late on heating. In the presence of a trace of a neutral salt they
coagulate on heating at temperatures very similar to proteid solu-
tions.
4. Fractional heat-coagulation shows the colloidal solutions are a
mixture of different substances.
5. The different constituents of the colloidal solution exhibit
different physiological action.
6. In the presence of an excess of neutral salts, or of salts of the
heavy metals, the colloidal solutions behave in a manneir similar to
proteid solutions.
7. When introduced into the circulation of pigmented rabbits, dogs,
and cats, certain of these substances (viz., the colloids designated
A, B, C, a. and ft) produce intra vascular coagulation of the blood in a
manner similar to a nucleo-proteid. They also hasten the coagul-
ability of the blood withdrawn from the carotid, and will, when
slowly injected intravenously in minute quantities into dogs, produce
a retardation of the coagulability of the intravascular blood, e.g., a
"negative phase."
8. Apparently these colloidal substances are, owing to both their
physical and chemical properties and their physiological behaviour,
the nearest synthesised bodies at present known to proteids.
'•An Experimental Examination iuto the Growth of the
Blastoderm of the Chick." By RICHARD ASSHETON, M.A.
Communicated by ADAM SEDGWICK, F.R.S. Received
November 12, — Read December 10, l#9b*.
In* making an experimental study of the growth of the blastoderm
of the chick, I had two chief objects in view :
350 Mr. R. Assheton. An Experimental Examination
(1) To test by actual experiment Duval's* theory of the formation
of the primitive streak.
(2) To try and determine experimentally whether the whole or
only part of the actual embryo is developed by the activity
of the primitive streak. And further, if only a part, to
determine its limits.
With regard to the first question it may be remarked that Duval's
account is generally accepted, although perhaps greater stress is laid
upon it by foreign and American writers than by embryologists in
this country.
According to Duval's account, there is in the freshly laid and unin-
cubated egg a groove which separates the blastoderm from the yolk.
The groove, he says, is broader and more conspicuous at the posterior
margin than at any other point.' This he compares to the anus of
Rusconi or blastopore of the segmenting, frog's egg.
During the first few hours of incubation the edge of the blastoderm
is said to advance over the yolk at every point except at this most
posterior margin bounding the groove, which he regards as equiva-
lent to the frog's blastopore. At this spot there is no advance. The
portions of the edge of the blastoderm adjoining this part swing
round to meet each other in the middle line, and eventually fuse
and form what Duval calls the " plaque axiale."
This structure is in reality the primitive streak, and, according to
Duval, it becomes visible as such during about the tenth to fifteenth
hours of incubation by reason of the subsequent hollowing out of
the subjacent yolk by the extension backwards of the sub-germinal
cavity.
Such a mode of growth would be very extraordinary and interest-
ing if true, and would be very acceptable to those who believe that
the growth in length of the vertebrate embryo is caused by a concre-
scence of two at first separated germinal rims.
Naturally this account of the formation of the primitive streak as
given by Duval is frequently quoted by the many adherents to the
concrescence theory. .
, During the last few years experimental methods have been intro-
duced much more freely into investigations of animal development.
Foremost amongst the workers upon these lines is Dr. Wilhelm Boux,
who experimented by destroying certain cells of the segmenting eggs
of frogs, and noting the result after some days of development. He
has been followed in similar work by Morgan and Time Tsuda and
others.
The eggs of frogs have been the object of experiment of a different
* " De la Formation du Blastoderme dans 1'QEuf d'Oiseau," ' Annales des
Sciences Naturelles, Zoologie,' vol. 18.
into the Growth of the Blastoderm of the Chick. 351
kind, such as that of Professor Oscar Hertwig, who studied the
various monstrosities obtained by mechanical compressions, by super-
maturation of the ovum, and addition of various salts to water in
which the eggs were developing. Similar work has been done upon
sea-urchin's eggs by several biologists (Pouchet and Chabry, Herbst,
<fcc.).
There are other most valuable records of the results obtained by
separating the several spheres of the early stages of segmentation of
eggs of Ctenophores, Echinoderms and Amphioxus by Chun, Driesch,
Wilson, and others.
Kastschencko, by injuring portions of the germ ring of Elasmo-
branch embryos, has produced very valuable evidence in connexion
with the concrescence theory, and Morgan has by similar methods
examined the development of Teleosteans.
As far as I know, an experimental study of the development of the
avian blastoderm has not hitherto been made.
The method adopted, which is very simple, was as follows. The
egg was first of all opened at one side, and a bristle inserted into the
yolk at some distance away from the blastoderm, to mark its anterior
and posterior axis.
The yolk, with its surrounding albumen, was then turned out into
a glass vessel having a rather greater capacity than that of an ordinary
egg shell.
The yolk was arranged so that the blastoderm floated uppermost,
and a wire or celluloid ring was placed over it to prevent the yolk
from floating to the surface.
A fine sable hair was then inserted in the blastoderm, and its posi-
tion measured by a micrometer eye-piece and recorded in tenths of a
millimetre. The vessel was filled up with albumen and covered
with a glass lid, and placed in the incubator at a temperature of
104° F.
Under these conditions, although development was slower than
under normal conditions, many embryos reached, after about forty-
eight hours, an age equivalent to a normal thirty to thirty-six
hours' chick with nine or ten pairs of mesoblastic somites. . }crJ<
To come now to the results of the experiments, it is clear that if
Duval's theory is correct a hair inserted in the area opaca at the point
a (fig. A (i)) ought to appear, in a specimen in which the primitive
streak is formed, somewhere in front of the primitive streak. It,
however, does not ; it appears in the area opaca behind the primitive
streak at a, fig. A (ii).
So again if the primitive streak is formed by the concrescence of
the posterior margin, the sables inserted at the posterior edge at XX
should either appear in the primitive streak or else prevent its
formation.
352 Mr. R. Assheton. An Experimental Examination
(i) A
r. A. — (i) Diagram of the unincubated Blastoderm of a Bird, (ii) Diagram of
the Blastoderm after the complete Formation of the Primitive Streak.
On the contrary, they are found far behind the primitive streak in
the area opaca.
These facts seem to show that the primitive streak is not formed
from the posterior edge of the blastoderm as Duval maintains.
As a rule, in the unincubated blastoderm the area opaca and area
pellucida are very fairly well defined.
If, when this is the case, a sable hair is inserted jusb within
the area pellucida at the point b, or if, when there is no such
distinction, the sable is inserted about one quarter the distance from
P to A, the sable hair is found, after the development of the primi-
tive streak, piercing the posterior end of the primitive streak —
whereas, according to Duval's account, it ought to be somewhere in
front of the primitive streak.
If a hair is inserted in the median line rather further towards the
centre of the blastoderm, it is found near the middle of the primitive
streak, or, if placed about half way between the inner edge of the
posterior part of the area opaca and the centre of the blastoderm (as
at c), it is found in the anterior part of the primitive streak ; and,
when the sable is inserted at the centre of the blastoderm, it appears
at the front end, or just in front of the primitive streak (fig. A, d).
The foregoing proves, I think, conclusively, that the primitr
streak is developed from that portion of the unincubated blastoden
which lies between the centre of the blastoderm and the posi
into the Growth of the Blastoderm of the Chid'. 353
margin of the area pellucida. The area opaca takes no part at all in
the formation thereof.
I may add that from a careful examination of surface views of
living and preserved specimens, and from sections, I find it just as
difficult to corroborate Duval's account of the formation of the
primitive streak as I do from the experimental study I have just
described.
I come now to the second part of the inquiry ; namely, what part
of the actual embryo does the primitive streak give rise to ?
A sable hair inserted at the centre of the blastoderm appears at the
anterior end of the primitive streak.
If such a specimen is allowed to develop for some hours longer,
until the medullary plate and medullary groove are clearly formed,
these structures are found to be in front of the sable hair ; that is to
say, the sable hair is still at the front end of the primitive streak
(fig. B). If a specimen, in which the sable hair has been inserted at
the same spot — that is to say, at the centre of the unincubated
blastoderm — is left until several pairs of mesoblastic somites have
appeared, the hair is found at the level of the most anterior pair of
somites (fig. B (iii)).
From these specimens it seems clear that all those parts in front of
the first pair of mesoblastic somites (that is to say, the heart, the
brain, and medulla oblongata, the olfactory, optic and auditory
FIG. B. — (i) Diagram of unincubated Blastoderm,
(ii) Blastoderm after 24 hours' incubation,
(iii) Blastoderm after 40 hours' incubation.
AO, area opaca j AV, area vasculosa ; N"Gr, medullary groove ; PS, primitive streak
X, point of insertion of sable hair.
354 Mr. R. Assheton. An Experimental Examination
organs and fore gut) are developed from that portion of the unincu-
bated blastoderm which lies anterior to the centre of the blastoderm,
and that all the rest of the embryo is formed by the activity of the
primitive streak area.
I have found it very difficult to determine, exactly, the anterior
limits of the embryo in the unincubated blastoderm. This, no doubt,
is due to the fact that, for the production of the anterior end of the
embryo, very complicated foldings of the blastoderm are called into
play, and the insertion of a bristle or the infliction of any injury to
the delicate parts of the blastoderm involved in the process, almost
entirely prevents anything like a normal course of development.
However, such little success as I have had gives the following
results : — A hair inserted at the most anterior border of the area
pellucida is found far in front of the primitive streak.
A hair inserted only slightly in front of the centre of the blasto-
derm appears (in a specimen in which the medullary folds are just
becoming visible) in the medullary plate in front of the primitive
streak. In older specimens, after the head -fold has been formed,
the embryos are extremely abnormal when the sable has been inserted
in the region under discussion.
Indeed, very few will develop as far as the formation of the head-
fold.
The only facts I can derive from the insertion of sable hairs in
this area are : —
( 1) That it interferes very seriously with the course of develop-
ment.
(2) That the bristle appears inside the two anterior horns of the
area vasculosa.
(3) That if placed some little way anterior to the centre it is found
apparently in front of the embryo, but it interferes so greatly
with the head-fold that it is difficult to say whether it has,
or has not, perforated the anterior part of the embryo.
I have shown that a hair inserted between the centre of the
blastoderm and the hinder margin of the area pellucida is found after
about twenty hours of incubation in the primitive streak. When a
specimen in which the sable has been similarly placed is allowed
to develop until several mesoblastic somites have been formed, it is
found to be posterior to the first formed mesoblastic somites.
For instance, in the specimen with me, the blastoderm measured
4*3 mm. in diameter. The sable was inserted 1'3 mm. from the
posterior edge of the blastoderm. After forty-one hours of incuba-
tion seven pairs of mesoblastic somites had been formed, and the
sable hair was a short distance posterior to the 7th pair of somites.
From such specimens as these we are, I think, bound to conclude
into the Growth of the Blastoderm of the Chick. 355
(ii)
.X
-J- X
FiG. C. — (i) Diagram of unincubated Blastoderm.
(ii) Blastoderm of Chick with seven pairs of Mesoblastic Somites.
that the primitive streak is converted directly into a part of the
embryo, that is to say, the part of the embryo posterior to, and in-
cluding the first pair of mesoblastic somites.
With regard to the area vasculosa, my experiments seem to indi-
cate that the part of the blastoderm which becomes area vasculosa
is that part which lies on the inner edge of the posterior part of
the area opaca of the unincubated blastoderm. It is along this
edge where, according to Koller,* a white crescent is always visible.
Koller, further, asserts that this white crescent is grooved. From
this crescent and groove Koller derives the primitive streak and
primitive groove by the conversion of the transverse crescent and
groove into a longitudinal streak and groove.
I think that all recent authors are agreed that it is not grooved,
and most admit that it has nothing to do with the primitive streak.
It is, however, quite true that a crescentic whiter area is sometimes
visible here, bat in, I think, the majority of cases there is nothing of
the kind to be seen.
When it is present a sagittal section of the hinder part of the
blastoderm seems to reveal its nature. In such a section a mass of
inner-layer cells, which would, perhaps, be more properly described
as a band of yolk containing numerous nuclei, although quite sharply
marked off from the underlying yolk-mass, can be detected. This
area corresponds in position to that part of the blastoderm from
which, according to experiments made with bristles, the area vas-
culosa is derived (figs. D, E).
A sable hair inserted in the yolk beyond the limits of the blasto-
* " Beitrage zur Kenntniss des Hiihnerkeims im Beginne der Bebriitung," ' Sitz.
Akad. der Wissensch.,' Wien, vol. 80, 1379. " TJntersuch. iiber d. Blatterbildung
im Hiilmerkeim," ' Arch. f. mikr.-Anat.,' vol. 20, 1881.
356
On the Growth of the Blastoderm of the Chick.
fi)
FIG. D.— (i) Diagram of unincubated Blastoderm,
(ii) Blastoderm after 24 hours' incubation.
(i)
X - -
__1 A O
-2VX-- AV
FIG. E. — (i) Diagram of unincubated Blastoderm.
(ii) Blastoderm with five Pairs of Mesoblastic Somites.
derm, if placed close to the edge of the blastoderm generally hinders
the development of that side. But if placed at some distance from
the blastoderm, it is eventually passed by the advancing edge of the
blastoderm, and is found within the area opaca, though usually a
streak is left between it and the edge of the blastoderm.
Proceedings. 357
December 17, 1896.
Sir JOSEPH LISTEE, Bart., F.R.C.S., D.C.L., President, in the
Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The Right Hon. Sir John Eldon Gorst, a member of Her Majesty's
Most Honourable Privy Council, was balloted for and elected a Fellow
of the Society.
The following Papers were read : —
I. " On the Dielectric Constant of Liquid Oxygen and Liquid Air."
By J. A. FLEMING, M.A., D.Sc., F.R.S., Professor of Elec-
trical Engineering in University College, London, and
JAMES DEWAR, M.A., LL.D., F.R.S., Fullerian Professor of
Chemistry in the Royal Institution, &c.
II. " On the Effect of Pressure in the surrounding Gas on the
Temperature of the Crater of an Electric Arc. Correction of
Results in former Paper." By W. E. WILSON, F.R.S., and
G. F. FITZGERALD, F.R.S.
III. " Influence of Alterations of Temperature upon the Electrotonic
Currents of Medullated Nerve." By AUGUSTUS W. WALLER,
M.D., F.R.S.
IV. " On Subjective Colour Phenomena attending sudden Changes
of Illumination." By SHELFORD BIDWELL, M.A., LL.B., F.R.S.
Y. " On the Occurrence of Gallium in the Clay-ironstone of the
Cleveland District of Yorkshire." By W. N. HARTLEY, F.R.S.,
and H. RAMAGE.
VI. " On some Recent Investigations in connection with the Electro-
deposition of Metals." By J. C. GRAHAM.
The Society adjourned over the Christmas Recess to Thursday,
January 21, 1897.
358 Profs. J. A. Fleming and J. Dewar. On the
** On the Dielectric Constant of Liquid Oxygen and Liquid
Air." By J. A. FLEMING, M.A., D.Sc., F.R.S., Professor of
Electrical Engineering in University College, London, and
JAMES DEWAR, M.A., LL.D., F.R.S., Fullerian Professor
of Chemistry in the Royal Institution, &c. Received
December 8,— Read December 17, 1896.
The exceedingly high insulating properties of liquid oxygen and
liquid air indicate that these bodies are dielectrics, and possess a
dielectric constant or specific inductive capacity which it is necessary
to determine. We have, therefore, lately made some measurements
which have enabled us to assign a number representing, in all
probability, a close approximation to these constants.
The remarkable non-conducting quality of these liquid gases for
electricity enabled us to employ a method which, generally speaking,
is not applicable to liquids other than those of very high specific
resistance, or insulating power.
The method used by us in these experiments consists in the
employment of a small condenser composed of metal plates which
can be plunged beneath the surface of the liquid gas, and the
capacity of this condenser measured when the dielectric between
the plates is first gaseous air at ordinary temperature and pres-
sure, and is next replaced by the liquid oxygen or liquid air.
In order to determine the capacity of this condenser, which is
necessarily small and of the order of 0*001 microfarad, we adopted
the well-known device of charging the small condenser with a
high potential (100 volts) and then discharging it into a much
larger, well insulated mica condenser, having a capacity of about
0*5 microfarad. This process was repeated ten times, and the larger
condenser was then discharged through a standardised ballistic
galvanometer. A specially constructed and highly insulated key was
employed to charge the small condenser by means of a battery of fifty
small lithanode secondary cells ; and then to discharge it into the
larger condenser. The success of this method depends entirely on
the absence of sensible leakage in the condensers, and it is essential
to show that the small condenser loses no sensible portion of its
charge by leakage or conduction during the interval which elapses
between disconnecting it from the battery and connecting it to the
large condenser, which acts as a reservoir.
In these experiments the small condenser consisted of seventeen
plates of carefully flattened aluminium, about 1 mm. in thickness ;
each plate being 5 cm. wide by 15 cm. long. In order to separate
the plates, small distance pieces of crown glass were employed,
Dielectric Constant of Liquid Oxygen and Liquid Air. 359
each fragment being about 3 mm. square and 1 mm. thick. Four
of these fragments were affixed to each metal plate with a touch
of shellac at the four corners and one fixed in the middle. The
seventeen plates were then piled one on the other, the glass frag-
ments acting as separators, and the alternate plates were connected
together by wires soldered to each series. A metal clamp kept all
the plates in position. The condenser so formed consisted of seven-
teen plates, eight being the positive, and nine the negative surfaces.
The glass distance pieces had a total surface of very nearly 1 per
cent, of the total opposed surface of the plates. The condenser so
formed had a capacity of O'OOIOSI of a microfarad when gaseous air
at 15° C. and normal pressure formed the dielectric.
If such a condenser having a capacity C' is charged to a potential
~V and then discharged n times in succession into a larger reservoir
condenser of capacity C, it is easy to show that at the end of the
n successive charges the quantity Q contained in the large condenser
is given by the series
Q = C'V(m-h
C
where
C+C'
Hence we have Q = C'V -- -(l-m»).
1 — m
The capacity C' of the small aluminium condenser may be con-
sidered to be made up of two parts ; a part which is changed when
liquid oxygen is substituted for gaseous oxygen or air on immersing
the condenser, and which thereby becomes increased. If K is the
dielectric constant of liquid oxygen, referred to that of gaseous
oxygen at —182° C. as unity; and if c. is the capacity of this variable
part of the condenser when the dielectric is gaseous oxygen, then
Kc is its capacity when liquid oxygen is substituted for the gaseous
oxygen at the same temperature.
In the next place there is a small part of the whole capacity due to
the glass separators. These, as a whole, have a surface very nearly
equal to 1 per cent, of the whole surface of the metal plates, and a
dielectric constant, as shown below, when cooled to —182° C., of 5'0.
Hence it follows that that part of the whole capacity of the con-
denser which is due to the glass separators, may be represented very
nearly by 5c/100.
This part of the capacity remains practically constant whether the
condenser is lifted out of the liquid oxygen into the cold gaseous
oxygen lying above it, and which is at nearly the same temperature,
or put into it, as long as the condenser is very nearly at the same
temperature in the two conditions.
VOL. LX. 2 E
360 Profs. J. A Fleming and J. Dewar. On the
Hence, when the small condenser is under the surface of liquid
oxygen its capacity C', as a whole, is
Kc+O05c,
and the whole quantity of electricity, Q, given up to the reservoir
condenser after n charges of the small one, charged to potential V,
have been put into it, is
Q =
/~i
where m = ^ — — - - - ~ and M = (l— ra»).
C + (K + 0-05)c 1— mv
Again, when the small condenser is lifted out of the liquid oxygen
into the gaseous oxygen lying on the surface, its capacity becomes
c+0'05c = l*05c, and the whole quantity Q' stored up in the reser-
voir condenser, after n charges at a potential V, is
Q'-
where m'= — - and M' = m (l—m'n).
C + r05c 1— m
If in each case the reservoir condenser is discharged through a
ballistic galvanometer, the " throw " or elongation of which is pro-
portional to the quantity of electricity sent through it, and if 0 and
<9' are the throws produced by the quantities Q and Q', we have
M
Q ros M
The ratio Ojtf is given from the observations.
To solve this equation completely and determine K would be diffi-
cult, since the quantity M is a somewhat complicated function of K.
We know, however, that the ratio of M/M' cannot be very far from
unity. A rough experiment had shown that K was a number in the
neighbourhood of 1*5, and a calculation shows that when ten dis-
charges of the small condenser are made in each case into the large
condenser, and if the large condenser has a capacity of 0'5 micro-
farad, and the small one a capacity of nearly O001 microfarad, that
the ratio M/M' = 1030/1019 nearly. Hence M/M' comes in as a cor-
recting factor of about 1 per cent, in value.
Before relying on the above method, it was necessary to prove that
the loss of charge of the small condenser was negligible during the
time elapsing between the end of the charge and the end of the dis-
charge of the small condenser.
Dielectric Constant of Liquid Oxygen and Liquid Air. 361
We found on trial that although the small condenser had a capacity
of only 0-001031 microfarad, it held its charge when charged with
100 volts, and placed beneath the surface of liquid air in the most
extraordinary way. The test for insulation was as follows : —
The small condenser was charged with 100 volts, and discharged
through the galvanometer instantly. The galvanometer throw was
95 scale divisions.
The small condenser was then charged and allowed to stand ten
minutes insulated. It was then discharged through the galvanometer,
and the throw was 90 scale divisions. In like manner it was charged
and insulated for forty-seven minutes, and the throw was then 80 scale
divisions.
The above figures show that the charge of the small insulated con-
denser decreased only by about 15 per cent, in three-quarters of an
hour when placed beneath liquid air, and hence the loss of charge in
one-tenth of a second was quite inappreciable.*
The same remarkable insulation is found when the small condenser
is held in the cold gaseous oxygen lying above the liquid oxygen.
The low temperature of —182° C. prevents any sensible leakage
across the glass distance pieces, and also increases the specific resist-
ance of the glass itself.
As a further instance of the very high insulating power of liquid air,
we may mention that we charged the small condenser when immersed
in liquid air with a Wimshurst electrical machine, and, after insu-
lating the condenser and waiting a few moments, closed the terminals
of the condenser by a wire. A small spark was seen at the contacts.
We thus constructed a little Ley den jar, the dielectric of which was
liquid air, and the coatings the aluminium plates. This liquid
Leyden jar held its charge perfectly.
Having satisfied ourselves in this manner that the condenser when
immersed in liquid air would lose no sensible portion of its charge
during the fraction (about one-tenth) of a second in which the charge
and discharge key was moving between its contacts, we proceeded to
experiment in the following manner. The condenser was placed in a
very large vacuum vessel, holding about two litres of liquid oxygen,
and it was charged as described, and discharged into a very good mica
condenser, made by Dr. Muirheacl, which had an exceedingly high
insulation. The process of charging and discharging ten times occu-
pied, perhaps, two seconds.
* These figures do not of course measure tlie electrical resistance of the liquid
oxygen alone. They show, however, that the immersion of the condenser in liquid
oxygen enormously decreased or entirely destroyed any surface leakage over the
small glass separators, and, as we have found by an independent examination,
increased the resistivity of the glass itself. The specific resistancs of liquid oxygen
itself is exceedingly high.
2 E 2
362
Profs. J. A. Fleming and J. Dewar. On the
The resultant charge having been measured on the ballistic gal-
vanometer, the condenser was lifted out into the cold gaseous oxygen
lying on the surface of the liquid oxygen, and before the condenser
had time to alter its form by rising in temperature, the same process
was repeated with the dielectric changed to gaseous oxygen at
-182° C.
The following Table I shows the observed ballistic throws, all
reduced to their equivalents at one common charging pressure of
100 volts :—
Table I. — Observations to Determine the Dielectric Constant of
Liquid Oxygen.
Potential to
which the
condenser was
charged in volts.
Ballistic throw
in cm., corre-
sponding to
10 charges of the
small condenser.
Ballistic throw,
reduced to corre-
spond to 10 charges
of the small con-
denser at 100 volts.
Exp. I. — Condenser at
ordinary temperature.
15° C.
103 -3
103-2
103-2
7-7
7-75
7-75
7-45
7-51
7-51
Exp. II. — Condenser in
liquid oxygen at — 182°
C.
103 -15
103-1
103-1
103-0
11-3
11-25
11-27
11-27
10-96
10-91
10-93
10-94
Exp. III. — Condenser
in cold oxygen gas
above the liquid oxy-
gen at- 182CC.
101-3
301-2
101-2
101-2
101-2
7'65
7-6
7-6
7'58
7'56
7-55
7-51
7-51
7-49
7-51
Exp. IV. — Condenser
in liquid oxygen.
101-3
101-2
10-9
10-85
10 '^"U A
10-72/bad-
Exp. V. — Condenser in
cold oxygen gas above
the liquid oxygen.
101-3
101-3
101-3
101-3
7'60
7'60
7-58
7 57
7-50
7-50
7-48
7'47
Exp. VI. — Condenser
in liquid oiygen.
101-4
101-3
101 "3
101-3
11 -i
11-0
10-95
11-0
10-95
10-86
10-81
10-86
Mean ballistic throw in gaseous oxygen
in liquid oxygen = 10"903 = 6.
7'502 = 0'. Mean ballistic throw
Dielectric Constant of Liquid Oxygen and Liquid Air. 363
It will be seen that the mean galvanometer throw, when the con-
denser was immersed in liquid oxygen, was 10'903 centims., and the
mean throw, when raised into the gaseous oxygen, was 7'146 centims.
One matter which we felt it important to examine, was whether
there was any correction needed for the change in the dielectric con-
stant of the glass separators with temperature.
Since these glass separators had a total surface of nearly 1 per
cent, of the area of the metal plates, the condenser may be regarded
as consisting of two condensers joined in parallel, one consisting of a
glass dielectric condenser having an effective surface of 1, and the
other a condenser having a liquid or gaseous oxygen dielectric
having an effective area of 99. In the course of these experiments
we have therefore examined the effect of low temperature upon the
dielectric constants of glass, paraffined paper, and mica. We find
that on cooling these bodies to —182° C. they experience a marked
reduction in dielectric constant. The dielectric constant of a certain
specimen of crown glass was reduced by 2T4 per cent, by cooling to
the temperature of liquid air or to —185° C. The dielectric con-
stant of paraffined paper was reduced by 28'4 per cent, under the
same circumstances.* We are engaged in a systematic examination
of the influence of very low temperatures on the dielectric constants
and specific resistances of the principal dielectric bodies. The crown
glass used as separators in the construction of our small condenser
had a specific inductive capacity of about' 6'0 at ordinary tempera-
ture, and this at the low temperature would be reduced to nearly 5'0.
Hence in estimating the capacity of the condenser, as constructed,
there comes in as we have seen a correction from the presence of the
glass. We selected glass in the first instance rather than ebonite or
sulphur, as we thought it probable we should use the same con-
denser in determining other dielectric constants, and we wished to
construct the separators of a material which was very rigid and not
easily acted upon by oils or other liquids.
Taking the formula above given, we can deduce from the observed
results the required constant, for, we have
0___ K + Q-05 1030
V' ~ 1'05 1019 '
*
and hence substituting for —t the observed ratio , we find
0 i'd\j'£
K = 1-491
* By another method we have found that for the glass of a glass te&t-tube the
dielectric constant was decreased 22*2 per cent, by cooling to the temperature of
liquid air. Under the same circumstances a certain specimen of mica decreased
only 3'01 per cent, in dielectric constant.
364 Profs. J. A. Fleming and J. Dewar. On the
as the dielectric constant of liquid oxygen referred to that of the
overlying gaseous oxygen at — 182° C. as unity. Since the alumi-
nium condenser is at the same temperature when the two measure-
ments are made, no correction is necessary for any change of form
of the condenser.
To determine the dielectric constant of liquid oxygen in terms of
that of a vacuum taken as unity, we require to know the dielectric
constant of the gaseous oxygen lying on the surface of the liquid
oxygen referred to the same unit.
Boltzmann and Klemencic have both shown that the true dielectric
constant of air at a temperature of 0° C. and 760 mm. is 1*00059.
That of oxygen gas at the same temperature and pressure is not
very different. Tf the value of K— 1 for gases varies directly as
the pressure, and if temperature per se makes no difference, then the
dielectric constant of the gaseous oxygen lying on the surface of the
liquid oxygen, and which has a temperature of —182° C. nearly, and
a . density about three times that of the gas at 15° C., is not far
from 1*002. Hence the correcting factor to be applied to the above
value of the dielectric constant of the liquid is at the most 1*002,
and the true dielectric constant of liquid oxygen at —182° C. and
under a pressure of 760 mm. is not far from 1*493.
We intend to examine this correction more closely.
As a matter of fact, we were not able to detect any difference
between the capacity of the small condenser when held in air at
ordinary temperature (15° C.) and pressure, and in the cold gaseous
oxygen at —182° C. lying on the surface of the liquid oxygen.
Until we are able to make a better determination we may take the
above number, . 1 '491, therefore, as representing in all probability a
close approximation to the dielectric constant of liquid oxygen.
The interesting question then arises how far does liquid oxygen
obey Maxwell's law, by which the product of the dielectric con-
stant and the magnetic permeability should be equal to the
square of the refractive index for waves of infinite wave-length P
The materials are at hand for making this comparison, as we have
ourselves just determined the magnetic permeability of liquid
oxygen, and find it to be 1*00287,* and the refractive index of liquid
oxygen has been determined by Professors Liveing and Dewar for
several different wave-lengths.f
* See Fleming and Dewar, ' Eoy. Soc. Proc.,' December, 1896, vol. 60, p. 283,
"On the Magnetic Permeability of Liquid Oxygen and Liquid Air."
t Liveing and Dewar, ' Phil. Mag.,' Sept., 1895, p. 269, " On the Eefraction
and Dispersion of Liquid Oxygen and the Absorption Spectrum of Liquid Air."
See also Liveing and Dewar " On the Refractive Index of Liquid Oxygen," ' Phil.
Mag.,' August, 1892, " On the Spectrum of Liquid Oxygen and on the Kefractive
Indices of Liquid Nitrous Oxide and Etliylene;" also Liveing and Dewar, 'Phil.
Dielectric Constant of Liquid Oxygen and Liquid Air. 365
Professors Liveing and Dewar determined the refractive indices
(/*) corresponding to certain wave-lengths (X) for the following wave-
lengths : —
Prom lines in the
spectrum of A. ^.
Cadmium / 4416 corresponds to 1-2249
" 16438 „ 1-2211
Thallium 5350 „ 1*2219
Lithium 6705 „ 1-2210
Sodium 5892 „ 1*2114
They state that they consider the best results are given by the first
two observations. Taking these wave-lengths 4416 and 6438, and
the refractive indices corresponding to them, we have calculated from
them, by the formula
and found it to be
x*-x? :
the refractive index for infinite wave-length
as follows: —
/* = 1*2181.
The square of this number is 1*4837, and this, therefore, is the value
of the square of the refractive index for waves of infinite wave-length
in liquid oxygen.
Taking the product of the dielectric constant, K = 1*491, as above
determined, and that of the magnetic permeability, p — 1*00287, as
previously obtained by us, we find that this product Kp is 1*495, and
hence that there is therefore a very fairly close agreement between
the number representing the square of the refractive index for waves
of infinite wave-length and the above product. The difference
amounts to about two-thirds of one per cent. Hence liquid oxygen
is a substance which very closely obeys Maxwell's law.
We have applied the same apparatus to the determination of the
dielectric constant of liquid air obtained in exactly the same manner,
and Table II below gives the results of the observations taken in
liquid air. The observed results, when corrected as above described,
give for the dielectric constant of liquid air the number 1*495, which
is slightly more than that of the liquid oxygen. As, however, by the
time the experiment was complete the liquid air had practically
become liquid oxygen owing to the nearly complete evaporation of
ihe nitrogen, the coincidence of the two results is only what was to
be expected.
Mag.,' October, 1893, " On the Refractive Indices of Liquid Nitrogen and Air;"
also Liveing and Dewar, 'Phil. Mag.,' Sept., 1888, " On the Absorption Spectrum
(luminous and ultra-violet) of large Masses of Oxygen."
366 Profs. J. A. Fleming and J. Dewar. On the
The Table II below gives the observational results in the case of
the liquid air — really, however, of liquid oxygen.
Table If. — Dielectric Constant of Liquid Air (practically Liquid
Oxygen).
In Liquid Air. In cold Gaseous Air.
Ballistic throw for Ballistic throw for
condenser charged to 100 volts. condenser charged to 100 volts.
9-5
9-6
9-5
6-5 .
6-6
6-6
9-4
95
9-55
6-51
6-51
9-7
9-55 —
Mean = 9'54 Mean = 6'54
Dielectric constant = ]'495.
With regard to the above-determined dielectric constants for liquid
oxygen and liquid air, it may be remarked that these numbers are
smaller than those which have been obtained for almost any other solid
or liquid substance of which we have been able to find the measured
results. It has been already pointed out that large dielectric constant
generally accompanies small specific resistance in a dielectric, and
vice versa. Hence, as the specific resistance of the liquid oxygen is
very large — it being a very fine insulator — it is not surprising to find
the dielectric constant very small. As above mentioned, at a very
low temperature, the dielectric constant of some other solid dielectrics
'has been found by us to be very much reduced, and hence an interest-
ing field of research is opened out for the examination of the change
produced by low temperatures on the dielectric constants of other well-
known solid insulators, such as paraffin, ebonite, gutta-percha, mica,
sulphur, spermaceti, and various frozen liquid insulators, such as the
numerous hydrocarbon oils, carbon disulphide, ice, &c.* We hope to
* Mr. W. Cassie, M.A., ' Phil. Trans.,' vol. 46, 1889, has given the results of
measurements on the changes produced in the dielectric constants of various
insulators by heating them. As far as we can see, our initial results at low tempera-
tures for glass and paraffin are consistent with his. It will he interesting to see
how this relatively small dielectric constant of liquid oxygen compares with that of
other dielectrics when these last are cooled to the same temperature.
Dielectric Constant of Liquid Oxygen and Liquid Air. 307
be in a position shortly to furnish further information on this point,
and, also, if possible, to say whether the fall in dielectric constant is
accompanied by a reduction in the refractive index ; that is to say,
whether Maxwell's law is obeyed at low temperatures.
We may add that we have already devised a method by which it
will be possible to construct a condenser without the above-described
distance pieces, and hence to free the resulting measurement from the
small uncertainty — amounting, perhaps, to about 1 per cent. — which
may affect the above-given numerical results, and which comes in in
consequence of the doubt existing as to the exact area of the separa-
tors, and also the exact dielectric constant of the glass at the low
temperature.
It is interesting to observe that the numbers which we have found
above for the dielectric constant of liquid oxygen and liquid air are
not very different in order, though somewhat smaller than the dielec-
tric constant as already determined for some other liquid gases,* such
as nitrous oxide and carbon dioxide.
In conclusion, we may add that we have been again much indebted
to Mr. J. E. Petavel for his kind assistance in making the above-
described observations and measurements.
Note added December 15.
In connection with the above investigation, it is interesting to note
one remarkable difference between the magnetic susceptibility of
oxygen in the liquid and in the gaseous state. The mass of 1 c.c. of
gaseous oxygen, taken at 15° C. and 760 mm., is 0*00134 gramme.
The mass of 1 c.c. of liquid oxygen, taken at — 182° C. and 760 mm.,
as determined by one of us (J. Dewar), is T1375 gramme. Hence
the ratio of the density of liquid oxygen to that of gaseous oxygen is
849 to 1.
The magnetic susceptibility of gaseous oxygen at 15° C. and 760 mm.,
as obtained from the figures given by Faraday and E. Becquerel, is
0143 X 10~c per unit of volume, whilst the magnetic susceptibility in
the liquid state is, as we have shown,t 228 x 10~c. Hence the ratio of
the magnetic susceptibility of liquid oxygen to that of gaseous
oxygen for equal volumes is 1594 to 1.
In other words, the magnetic susceptibility of liquid oxygen is nearly
twice as great as that of gaseous oxygen for equal masses. The
inference is that magnetic susceptibility is not merely a property of
the molecule per set but is a function of the state of aggregation.
* See F. Linde, ' Journal de Physique,' vol. 5, Sept., 1896, p. 413, " On the
Dielectric Constant of Liquid Gases."
t See Fleming and Dewar, ' Roy. Soc. Froc.,' vol. 60, p. 283, December; 1896.
368 Mr. S. Bidwell. On Subjective Colour Phenomena
Note added December 18.
In addition to the arrangements above described for determining'
the capacity of the small condenser, we have also employed the well-
known method of charging and discharging the small condenser
through a galvanometer by means of a contact-maker driven at a
speed of sixty contacts per second by an electrically controlled
tuning-fork. By this means a steady deflection of the galvanometer
is obtained due to the passage of the rapidly recurring discharges
through it. Preliminary observations with this apparatus have con-
firmed the above-given value for the dielectric constant of liquid
oxygen, and by a modification of it we hope shortly to make a very
careful re-determination of the constant.
" On Subjective Colour Phenomena attending sudden Changes
of Illumination." By SHELFORD BIDWELL, M.A., LL.B.,
F.R.S. Received December 10,— Read December 17, 1896.
The investigation which forms the subject of this paper originated
in an attempt to account satisfactorily for the colour phenomena
exhibited by Mr. C. E. Benham's "Artificial Spectrum Top," which,
when it was brought before the public, about two years ago, excited
considerable interest.
The top consists of a disk of cardboard about 4J in. (1O8 cm.) in
diameter, mounted upon a spindle. One half of the disk is painted
black; upon the white ground of the other half are drawn four suc-
cessive groups of three black lines, having the form of concentric
arcs of 45°, which are at different distances from the centre, as shown
in the annexed figure ; the thickness of the lines is about -£$ in.
(1 mm.). When the disk rotates, each group of black lines generally
appears to assume a different colour.
The nature of the colours thus developed depends upon the speed
of the rotation, and upon the quality and in tensity of the illumination.
After several trials, I found that no better results, on the whole,
could be obtained than when the disk was illuminated by a 16-candle
power incandescent lamp, with a ground glass bulb, at a distance of
about 6 in. (15 cm.), and was caused to turn about five times in a
second. These, therefore, were adopted as the standard conditions
for my experiments, the disk being mounted upon a horizontal axis,
driven by an electro-motor, and the speed regulated by comparison
with the ticks of an ordinary watch.
When the disk rotates under the specified conditions and in the
direction indicated by the arrow in the figure, the inner group of
attending sudden Changes of Illumination.
369
Benham's Top.
lines appears, to my vision, to become bright red, the next group
pinkish-brown, the next a dilute olive-green, and the outer group
dark blue. If the direction of rotation is reversed, the order of the
colours is also reversed.
By far the most striking of these several hues is the first named ;
hardly any one has the slightest hesitation in pronouncing it to be
bright red. As to the blue, there is very rarely any difference of
opinion, though it has sometimes been called bluish-green. The
hues of the two intermediate groups are much more undecided and
difficult to specify, especially when they are seen separately.
The only serious attempts that I know of to explain the origin of
the colours shown by the top are those of Professor Liveing and of
Captain Abney.* Professor Liveing's explanation is based upon the
two hypotheses that the eye perceives certain of the coloured con-
stituents of white light more quickly than others, red being the first
to show itself, and that the duration of the impressions due to the
different constituents also differs, blue being the last to disappear.
Captain Abney thinks that the results would be sufficiently accounted
for if the order of persistence of the three colour sensations were
violet, green, and red.
Several objections might be urged against these explanations, but
the adequacy of either of them seems to be conclusively negatived by
* ' Nature,' vol. 51, pp. 167, 292.
370 Mr. S. Bidweli. On Subjective Colour Phenomena
the fact that if the thickness of the lines on the disk is much greater
than 1 mm., or, more accurately, if it subtends at the eye a greater
angle than about one-fifth of a degree, the red and some of the other
colours appear only upon the borders of the lines, their inner portions
remaining black or grey.
The true solution, at least as regards the red and the blue, is, I
think, to be looked for in certain phenomena attending sudden
changes of illumination, which, so far as I have been able to ascertain,
have not hitherto been observed.
The following are a few out of a large number of experiments that
have been made during the last four months. They are described,
as far as possible, in logical and not in chronological order. Persons
unaccustomed to visual observations will not easily perceive some of
the effects mentioned.
Experiment I.
A circular aperture ^ in. (1'3 cm.) in diameter was made in a sheet
of blackened zinc and was covered with thin white writing paper.
Diametrically across the aperture a strip of tinfoil -^ in. (1 mm.)
wide was attached to the paper. The aperture was closed by a
shutter, which could be very rapidly opened by means of a strong
spring. The sheet of metal was placed over a window in one side of
alight-tight box, inside which at a distance of 1 ft. (30 cm.) from the
aperture was an incandescent lamp of 8-candle power with a ground
glass bulb. The observations were made at a distance of about 1 ft.
from the box, the room being in darkness.
When the shutter was suddenly opened, several curious phe-
nomena appeared simultaneously. The period of their duration was
difficult to estimate ; it was probably more than one-twentieth of a
second and less than one-tenth.
(1) Immediately after it was revealed, the small luminous disk
first increased in size with extreme rapidity, and afterwards became
somewhat smaller, being in its final condition still larger than at the
moment of exposure. This effect was more easily seen when the tin-
foil strip was looked at : it seemed to become at first much thinner,
then thicker again.
(2) At the moment when the disk was uncovered, a luminous
halo, like a broad ring, appeared to start from its margin and spread
outwards through a distance of more than an inch (2'5 cm.) in every
direction ; then it rapidly contracted and disappeared. The halo was
blue or blue-violet in colour, and seemed more sharply defined upon
its inner than upon its outer border.
(3) Contemporaneously with the existence of the halo, the disk
was surrounded by a bright red corona, which, like the halo,
expanded outwards, and then contracted. There was not, however,
attending sudden Changes of Illumination. 371
at any stage a dark interval between the corona and tbe disk ; more
probably the inner edge of the corona was slightly within the appa-
rent permanent boundary of the disk. The red corona was very
narrow ; its greatest width appeared to be rather less than 1 mm., or
about one-fifth of a degree. The effect was best seen when the
attention was directed upon the tinfoil strip, which for a moment,
after the exposure, became bright red, the coronas, or red borders, of
the adjoining semi- disks meeting or perhaps overlapping one another.
The apparent temporary excess of the area of the disk above its final
area, as mentioned in (1), was probably due to the evanescent red
border.*
It is remarkable that repeated experiments had been made with
this and similar apparatus for several weeks before the existence of
the red border was detected, even though something of the kind was
looked for. The difficulty is, not to see it, but to know that one sees
it; when once it has been perceived it becomes very conspicuous.
The phenomenon is beyond doubt constantly met with, and habitu-
ally ignored, in daily life. Since my first observation of it I have
many times noticed flashes of red upon the black letters of a book or
upon the edges of the page ; bright metallic or polished objects often
show it when they pass across the field of vision in consequence of a
movement of the eyes, and it was an accidental observation of this
kind that suggested the following experiment.
Experiment II.
(1) The zinc plate of the last experiment was taken from the box,
and the aperture in the plate was covered with thin paper. A
ground glass lamp of 8-candle power, attached to a flexible cord, was
put behind it, and the whole was moved rather quickly either back-
wards and forwards or round and round in a small circle at a
distance of a foot or so from the eyes. The edges of the straight or
circular streak of light thus formed were bordered with red.
(2) A 16-candle power lamp was substituted for the other. The
red border then appeared to have a greenish-blue band inside it,
slightly encroaching upon the streak of light ; probably, however, it
was only the apparent or irradiation boundary that was thus affected,
not the true geometrical boundary.
(3) The paper was removed, and the 8-candle power ground-glass
lamp was again placed behind the aperture. The red could now
no longer be seen, but the greenish-blue border remained.
(4) When the 16-candle power lamp was used in the same way
* The effect may be seen without the use of the spring shutter, if a black screen
be held before the eyes and suddenly removed, but it is more difficult to hit upon
the exact position of the disk.
372 Mr. S. Bidwell. On Subjective Colour Phenomena
without any intervening paper, no coloured border could be seen,
owing, as it seemed, to the glare.
Experiment III.
The aperture in the metal plate was again covered with white
paper, having a strip of tinfoil across it, and the plate was fixed
before the window in the box, as in Experiment I ; a 16-candle power
lamp was placed immediately behind it. When the lamp was
switched on, the red border was distinctly seen to be backed with
greenish -blue, the red itself being much less evident than when the
lamp was 18 in. (45 cm.) behind the aperture.
I have hitherto failed to detect any greenish-bine near the border
when the disk was suddenly illuminated by the shutter method of
Experiment I, instead of by switching on the lamp.*
Experiment IV.
~ The object of this experiment was to ascertain whether the red
border could be produced by the sudden accession of light which
contained no red constituent. Ten different coloured glasses were
successively interposed between the lamp and the aperture with the
shutter. In every case when the spectroscope showed that the glass
transmitted red light, the tinfoil strip became red, but never other-
wise. For example, it reddened with a dark blue cobalt glass, but
not with a blue glass which transmitted much more light, but inter-
cepted the red end of the spectrum.
Experiment V.
The momentary, redness around the edge of the suddenly illumi-
nated disk and along the tinfoil strip, as described in the account of
the previous experiments, can only be seen by a practised observer.
By a different method, however, it can be made quite evident to
almost any person whose vision is normal.
The paper-covered aperture in the box was arranged as before, but
the shutter was not used. An incandescent lamp was placed inside
the box, and a second lamp outside, at a distance of a few inches
from the aperture, the observer's eyes being shaded from it by a
screen. The tinfoil strip was on the interior side of the paper, and
nothing was seen of it from outside, except when the lamp in the box
was alight.
A rotating commutator was constructed, by means of which
* [Since this was written, I have found that the greenish-blue may be shown by
the shutter method without difficulty if the distance of the lamp from the aperture
is suitably adjusted. — Dec. 19.]
attending sudden Changes of Illumination. 373
current could be supplied to the two electric lamps in the following-
manner : — During half a turn of the commutator, no current to
either lamp ; during the succeeding one-sixth of a turn, current to
the interior lamp only ; during the remaining one-third of a complete
turn, current to the exterior lamp only.
Starting with darkness, and turning the commutator quickly
through 180°, the observer saw, as soon as the interior lamp was
lighted, the shadow of the tinfoil, which was, as usual at the initial
stage, of a bright red hue ; but a small fraction of a second later,
before it had time to lose its rodiiess and become black, the image
was obliterated by a flood of light from the exterior lamp, while at
the same moment the other lamp was extinguished.
When the commutator was caused to make four or five turns per
second, the image of the tinfoil was almost continuous, and was at
once recognised by inexperienced observers to be red.*
This experiment was repeated in another form, the arrangement
being such that the light of two lamps was interrupted by screening,
instead of by breaking the current ; the changes in the illumination
could thus be made more rapidly.
Two black cardboard disks, from each of which a sector of 60° had
been cut out, were mounted 3J in. (9 cm.) apart at the ends of a
horizontal axle, being so fixed that the posterior edge of the opening
in one of the disks was exactly opposite to the anterior edge of that
in the other. Between the disks, and in a parallel plane, was sus-
pended a sheet of white paper, across the middle of which a narrow
strip of tinfoil was gummed. Two clear glass electric lamps were
placed near the outer faces of the disks at the same height as the
axis, the incandescent filaments being directed horizontally. To an
observer looking at the plain side of the paper across the edge of one
of the disks, while they were rotating slowly in the proper direction,
the paper first appeared dark all over, then it was illuminated from
behind by one of the lamps, the dark strip becoming visible ; finally,
it was illuminated from the front by the other lamp, and the strip
could no longer be seen. When the angular velocity was sufficiently
increased, the strip was seen continuously, or nearly so, and its colour
was, as before, bright red.
Experiment VI.
From a disk of white cardboard 6 in. (15 cm.) in diameter a sector
of 60° was cut out ; the remainder of the disk was divided into two
* The lamps used in this experiment were made to my order. They are of
8-candle power and have very thin filaments, the efficiency being 2'5 watts per c.p.
They were worked at a pressure of 6 per cent, above their marked voltage, and the
incandescence responded very quickly to the current.
374 Mr. S. Bid well. On Subjective Colour Phenomena
equal parts by a straight line from the centre to the circumference,
and one of these parts was painted black. The disk was attached to
a horizontal spindle, turned by a motor at the rate of five or six
revolutions per second, while its front was illuminated by a lamp of
16-candle power. A white card, upon which was a black line, or a
design composed of black lines, was supported behind the disk, and
viewed intermittently through the open sector. When the rotation
was such that the open sector succeeded the black portion of the
disk and was succeeded by the white portion, the black lines became
red.
This experiment is identical with the last, except that the white
ground is illuminated entirely by reflected light. In conjunction
with the others, it indicates with certainty the origin of the remark-
able red colour shown by Benham's top.
The disk with the open sector affords a mucli more convenient
means than the top of exhibiting the colour phenomena. If a disk
with an open sector of 45° or 60° is made of white cardboard, and a
movable black half disk is mounted in front of it upon the same axis,
we may, by suitably adjusting the position of the black half disk
with regard to the opening, produce in a fixed object all the tints
shown by the top, as well as intermediate ones ; .and the object itself
may be easily changed to suit the conditions of an experiment.
Experiment VII.
If the commutator of Experiment V, or the disk with the open
sector of Experiment VI, be turned in the reverse direction, the
strips of tinfoil or the black lines appear to become blue (instead of
red), like the outer group of lines in Benham's top when it spins in
the direction indicated by the arrow in the figure. This appearance
is partly, if not altogether, illusory. It is the bright ground in the
immediate neighbourhood of the black lines that becomes blue ; the
lines themselves (except possibly just within their extreme edges)
become a neutral grey, owing to the alternations of light and dark-
ness or of white and black.
A card with some black lines 1 mm. thick drawn upon it was
placed behind the disk with the open sector of Experiment VI, which
was turned in the directiou such that the open sector was pre-
ceded by white and followed by black. The lines presented the
appearance of having been drawn with blue ink upon imperfectly
sized paper, a blue stain having apparently spread for a short dis-
tance on both sides of the lines.
Lines of gradually increased thickness were successively employed
until at last they had the form of bands f -in. wide ; and even in this
latter case it was not easy to see that the bands themselves did not
become blue, but only their outlying borders.
attending sudden Changes of Illumination. 375
When, however, a visiting card which had been blackened over its
whole surface was placed behind the rotating disk, it merely turned a
lighter black, or rather grey, in which it was impossible to imagine
the slightest tinge of blue.
A small piece of white paper which was subsequently attached to
the middle of the card became blue around its edges when the disk
was turned, but the blue did not encroach at all (or if at all, only to
a very small extent) upon the black ground.
When these observations have been made it becomes possible to
recognise that the apparently blue lines in the top are themselves
really grey, and only bordered externally with blue.
Experiment VIII.
The natural conclusion from the observations described above is
that if a black disk were suddenly formed upon a bright ground, the
disk would for a moment appear to be surrounded by a blue border.
I was not successful in devising a satisfactory arrangement for
suddenly creating a black disk, but the effect is sufficiently shown in
the following manner.
An aperture 1J in. (3 cm.) in diameter was cut in one side of a
wooden box and was covered with white paper ; one half of the
aperture could be suddenly covered by a sliding metal shutter which
was actuated by a spring : a lamp was placed inside the box. When
the shutter was operated, a blue band 1 or 2 mm. wide appeared on
the bright ground just beyond and adjoining the edge of the shutter
when at rest. Its duration was thought to be slightly longer than
that of the red border of other experiments, and it appearently dis-
appeared by retreating into the black edge of the shutter.
When the shutter was moved by hand across the field at a slower
speed, its edge was seen to be preceded by a thin blue border, which,
when the shutter reached its limiting stop, appeared to reverse the
direction of its motion and return into the shutter.
The blue border is much less conspicuous and more difficult of
observation than the red one. In order to see it plainly careful
adjustment of the light is necessary. An examination of the effect
through coloured glasses was attended by uncertain results.
Remarks on the Experiments.
The phenomenon which in the account of Experiment I has been
spoken of as a blue halo may be due either to a momentary sympathetic
excitement of the nerve fibres of the retina in the neighbourhood of
those directly acted upon by the light, or, as I think, less probably,
to light scattered by the imperfectly transparent media of the eye.
In the latter case its rapid disappearance might be accounted for
VOL. LX. 2 P
376 Mr. S. Bidwell. On Subjective Colour Phenomena
partly by the diminished sensibility of the retina after the first
moment and partly by the contraction of the iris. The dark in-
terior of the halo, which begins to appear soon after its formation,
is probably connected with a class of visual sensations which have
been specially studied by M. Aug. Charpentier.* The sensation of
luminosity is followed very shortly after its first excitment by a brief,
dark reaction, and it is perhaps the momentary revival of the
luminosity after this reaction that gives the halo the appearance of
retreating into the bright disk.
Bufc whatever the cause of the halo, there can hardly be any doubt
that the corona or narrow red border is due to sympathetic excitation.
When the red nerve-fibres of the Young- Helmholtz theory are
affected by light the intensity of which does not exceed a certain
limit, the immediately surrounding red nerve-fibres are for a short
period sympathetically affected, while the violet and green are not
so, or in a much less degree.
It must be confessed that it is more difficult to offer a reasonably
simple explanation of what happens when the intensity of the light
exceeds the limit above indicated, and the band of greenish-blue con-
sequently appears in addition to, or in place of, the red border. It
is, perhaps, preferable to refrain at present from any speculation on
the subject.
When a Benham's top is spun in bright daylight or weak sunshine,
it is quite possible to distinguish both the red and the greenish-blue
at the same time, the latter encroaching somewhat upon the white
ground; its persistence is greater than that of the red, as can easily
be seen when the top is turning rather slowly. The greenish-blue
appears to be of the hue that is complementary to red, and it is evi-
dently the development of this colour that makes the red so much
less conspicuous when the top is illuminated by daylight than when
artificial light is employed.
The obvious method of accounting for the formation of the blue
border around a patch in a bright field from which light has sud-
denly been cut off, is to suppose a brief sympathetic reaction in the
nerve-fibres adjacent to those from which the exciting stimulus has
been withdrawn, this reaction being more marked in the red fibres
than in the green and violet, or perhaps occurring in the red fibres
only, at least when the light is of the usual intensity. If the red
fibres just outside the darkened patch ceased for a moment to
respond to the luminous stimulus, in sympathy with those inside
the patch, the appearance of a blue border would be produced.
In sunlight I have sometimes found that the lines in Benham's top
which ordinarily appear blue, assumed a reddish colour; under
* 'Comptes Rendus,' vol. 113 (1891), p. 147.
Effect of Pressure on Temperature of Crater of Electric Arc. 377
strong illumination therefore the sympathetic dark reaction would
seem to be least in the case of the red fibres.
Subjective colours of the same class as those shown by Benham's
top, but not nearly so conspicuous, have long been known. Helm-
hoi tz* mentions that if a rotating disk with black and white sectors
is looked at fixedly, each white sector appears to be reddish along its
leading border and bluish along its rear border. He also remarks
that these colours are more easily seen upon a disk covered with two
spiral bands, black and white, of equal breadth. From these and
other observations, Helmholtz concludes that when a point of the
retina is exposed to rapid alternations of white light and of darkness,
causing successive states of increasing and decreasing excitation, the
moment of maximum excitation is not the same for all colours. It
has, however, been shown above that in analogous cases the red
originates in a portion of the retina which has not been exposed to
the direct action of light, while the blue originates in a portion
where light has not ceased to act. Helmholtz's supposition therefore
does not apply — at least to the class of colours at present under con-
sideration.
I have not made any attempt to account for the more feeble
colours exhibited by the two intermediate groups of lines in
Benham's top, nor for the changes which occur when the speed of
rotation is increased. These effects no doubt result, at least in part,
from modifications of the phenomena already discussed. But for the
present I am compelled to discontinue the experiments on account of
the disagreeable and probably injurious effects which they produce
upon the eyes.
" On the Effect of Pressure in the Surrounding Gas on the
Temperature of the Crater of an Electric Arc. Correction
of Results in former Paper." By W. E. WILSON, F.R.S.,
and G. F. FITZGERALD, F.R.S. Received November 30,
—Read December 17, 1896.
In May, 1895, a preliminary paper by one of the authors was read
at the Royal Society, in which is described the apparatus used for
these experiments, and the results which were then obtained.
The primary object of this research was to determine, if possible,
whether the temperature of the crater in the positive carbon varies
when the pressure in the surrounding gas is changed.
It has been suggested that the temperature of the crater is that of
* <Phys.Optik,'§23.
VOL. LX. ^ r'
378 Messrs. W. E. Wilson and G. F. Fitzgerald.
boiling carbon. The most modern determinations give this tem-
perature of the crater as about 3300 — 3500 C.*
If this is the true boiling point of carbon, it is then clear that
solar physicists must find some other substance than solid carbon
particles to form the photospheric clouds in the sun, as the tempera-
ture of this layer is most probably not below 8000 C.,f unless, indeed,
the pressure in the solar atmosphere is sufficient to raise the boiling
point of carbon to about this temperature (see p. 381). It is in
order to throw some light on this subject that these experiments
were undertaken.
The gas used in our first experiments was nitrogen, and we found
that the radiation from the crater fell off in a. most remarkable
manner whenever the pressure was raised in the box surrounding
the arc. This falling off was not due to any very large extent to
visible cloud or smoke, and the crater seemed so much reduced in
temperature as to glow with only a red heat. This seemed to show
that the temperature of the crater depends on how much it is cooled
by the surrounding gas, and not on its being the temperature at
which the vapour of carbon has the same pressure as the surrounding
atmosphere.
It was found that we were limited to pressures not exceeding about
20 atmos., as at this pressure we could not withdraw the negative
carbon sufficiently to see into the crater without the arc breaking.
We were then only able to obtain a current from a battery of accu-
mulators which had an E.M.F. of 110 volts. Since then we obtained
a Crompton dynamo which could give 300 volts and 15 amperes, and
which was driven by a turbine.
From the great difficulty of obtaining a sufficient quantity of pure
nitrogen under pressure, we obtained a 20 ft. cylinder of air com-
pressed to 120 atmos. With this we tried a series of experiments,
and these at first seemed to corroborate our former ones, in which we
used nitrogen, but we found that at any rate some of the radiation,
and possibly a great deal of it, was cut off by the formation of what
appeared to be red fumes of N"O2. We found no absorption from
this cause so long as the pressure was nearly atmospheric, but at
about 100 Ibs. pressure this gas was formed with great rapidity, and
undoubtedly cut off a great deal of the radiation. We easily con-
firmed our belief in the presence of this gas by its well known
absorption spectrum.
Lest heat dissociation might cause an apparent increase in the
amount of NO2, we tried heating some of this gas in a flask. We
observed that when hot the brown fumes became golden yellow, and
* Wilson and Gray, ' Koy. Soc. Proc.,' vol. 58 j Violle, ' Journ. de Phys.,' 3rd
series, vol. 2, 1893, p. 545.
f Wilson and Gray, < Phil. Trans.,' A, vol. 185, 1894.
Effect of Pressure on Temperature of Crater of Electric Arc. 379
the absorption bands nearly disappeared, so that the heating could
not have been the cause of the apparently enormous production of
N02 at high pressure.
We next tried whether oxygen blown into the arc would burn up
the carbons, but found it did not do so to any serious extent, and so
tried the arc in a compressed atmosphere of this gas.
The arc burned very nicely indeed in the oxygen, the carbons
keeping a good shape, and a very steady crater. The oxygen was,
however, so contaminated with nitrogen that at high pressure enor-
mous quantities of NO2 were again formed, so that we could not
proceed further with the radiation experiments. The arc was a
bright blue bead, about the size of a pea, and the spectrum was a
beautiful banded one.
From these results we concluded that the reduction of radiation,
and red-hot appearance of the crater in the former experiments in
nitrogen, were due to its being contaminated with oxygen and to the
large quantities of N02, which were formed by the arc when under
pressure.
We next tried the arc in hydrogen. The gas was obtained as pure,
but contained hydrocarbons as an impurity, possibly from having been
compressed into a cylinder which had previously been charged with
coal-gas.
The arc in hydrogen at atmospheric pressures was a long, thin
flame, that moved as far up the carbons as possible ; especially on the
negative carbon it walked up a cm. along the cone. It went so far
that it fuzed the copper ring that held the negative carbon, and we
had to replace it by an iron wire lashing. It was very unsteady, and
trees of soot and a deposit of hard graphitic carbon formed on this
positive carbon as if there were electrolysis of the hydrocarbon, and
carbon were electro -negative compared with hydrogen. This growth
took place all round the crater, while there was no tendency for any-
thing to grow on the negative carbon.
The arc was only 5 — 6 mm. wide, and sometimes over 2 cm. long.
There was a green outer flame, with a bright red line not a mm. wide
down the middle of it. Where it impinged on the negative carbon
there was a bright red flame from the middle of the bright spot on
the carbon. The outer greenish part seemed to give much the same
spectrum as the green cone in a Bunsen burner, while the red flame
and line was undoubtedly glowing hydrogen. As we saw the C and F
hydrogen lines very distinctly, the red C line being dazzlingly bright
and not nearly so wide as in a coil spark at atmospheric pressure
whenever the image of the red part of the arc was thrown on the
slit of the spectroscope, the appearance was quite like that of a solar
prominence.
The end of the positive carbon was pitted into a number of craters
2 G 2
380 Messrs. W. E. Wilson and G. F. Fitzgerald.
as the arc was very unsteady, and when the pressure was raised it
was almost impossible to keep an arc going, partly because the arc
broke when it was elongated the least bit, and partly because a com-
plete lantern of soot trees grew all round the crater, and seemed to
short-circuit the arc from time to time.
The arc being very unsteady, no satisfactory reading of the voltage
and current was possible. At from 60 to 80 Ibs. pressure the voltage
varied from 60 — 80, and the amperes kept continually varying from
15—20. At 40 Ibs. with 20 amperes the volts varied from 50—60. The
crater was not well developed, so that the radiation observation, even
at low pressures, was not very satisfactory, while at high pressures
the arc was too short to see into the crater at all, and the lantern of
soot trees hid a considerable length, 3 or 4 mm. of the negative carbon
besides. The radiomicrometer gave 440 divisions with a good arc in
air, and 380 with the moderately good crater in hydrogen. But this
difference is no greater than would often occur with a good and
moderately good crater, so that there is not any proof of a difference
of temperature due to cooling power of hydrogen. These experi-
ments showed us that it was quite hopeless to get any measures of
radiation under pressure with hydrogen.
We finally tried an atmosphere of carbon dioxide. We used a
cylinder of liquid C02, which was connected to our arc box by a
copper tube and stop valve. The arc burned fairly well in this gas,
and, except for the difficulty of getting a sufficiently long arc at
pressures above 150 Ibs., some pretty satisfactory measures of radiation
were obtained. We found that whenever the pressure was suddenly
reduced, there was a fog formed in the box, which cut off the light
enormously. Also by looking down the steel tube, which is closed at
its end by a lens, we could see powerful convection currents in the
gas which scattered a lot of light. At high pressure the refraction due
to these currents prevented any sort of an image of the crater being
formed while the pressure was varying. While the pressure was steady
a good image could be formed. This tube is nearly 3 ft. in length,
and only \ in. in bore, and it would naturally take time for the gas
to settle down throughout its length. We propose to have this tube
removed, and the aperture in the box closed by a strong piece of plain
glass, and to form an image of the carbons by a lens placed at a suit-
able distance outside. This we expect will remove the difficulty
arising from these convection currents.
The result of all these experiments so far is that it would require
more evidence than we have been able to get, to affirm that either
the temperature of the crater of the arc is raised or lowered by
pressure. We got some very concordant observations, which showed
the temperature to be lowered with pressure, and in which at the time
we could see no evidence of absorption by fog, but then, at other
Effect of Pressure on Temperature of Crater of Electric Arc. 381
times, there was undoubtedly absorption 'from this cause. We
certainly got no evidence that there is any appreciable increase
of temperature. When the arc was started in the gas at a low
pressure and then the pressure was raised, the radiation at the low
pressure was greater than at a high pressure ; but when the arc was
started first in the gas at high pressure, and then the pressure
reduced, the radiation was rather higher in the gas at high pressure.
From all this we concluded that the greater part of the differences
we were observing were due to the absorption of the light in the long
tube already mentioned, which increased the longer the arc was
kept burning, and was probably greater at high than at low pressures.
The best observations were made with variations of pressure from 15
up to 100 Ihs. per sq. in., and there seems very little evidence of much
change of radiation with this change of from 1 up to between 6 and
7 atmos.
The whple question is surrounded with great difficulty. If the
carbon be really in equilibrium with its own vapour at the tempera-
ture of the crater and at the pressure of the surrounding atmosphere,
some relation must exist between the change in pressure and change
in temperature of the crater. If we knew the latent heat of volati-
lisation of carbon, we should be able to calculate the change of tem-
perature from the well-known thermodynamic formula
ST Av
Aw can certainly be approximately determined on the supposition
that the absolute temperature of the crater is fifteen times the abso-
lute temperature of the freezing point, i.e., 3800. We thus get for
gaseous carbon Av = 104, q.p., at this temperature. For 1 atmos. f>p
= 106, q.p., so that
cT 1Q1U
Hence, unless the latent heat of carbon be enormously great com-
pared with that of other substances, cT/T will be considerable. If X
be as great as the latent heat of vaporisation of carbon given by
Trouton's law, i.e., about 4000 calories, or 16'8 X 1C10 ergs, £T/T
would be about -fr, and £T would be nearly 220° C. for each atmo-
sphere, and a change of pressure of about 18 atmos. would raise the
temperature of the crater to that estimated for the sun. The corre-
sponding increase of radiation would be very great, for the radiation
varies, at least approximately, as the fourth power of the absolute
temperature. This would lead one to expect that the radiation would
be nearly doubled for each 4 atmos. added. Such an increase as
this certainly does not take place, so that we may conclude that
either the temperature of the crater is not that of boiling carbon,
382 Effect of Pressure on temperature of Crater of Electric Arc.
or else that the latent heat of volatilisation of carbon is very con-
siderably greater than that calculated from Trouton's law. Even
though this latent heat were as great as the heat of combustion of C to
C02, i.e., 7770, there would be an increase of about 70 per cent, in the
radiation for an increased pressure of 6 atmos. Such an enormous
latent heat is unprecedented, and yet our experiments would, almost
certainly, have shown such an increased radiation as this. So far,
therefore, the experiments throw considerable doubt on the probability
that it is the boiling point of carbon that determines the tempera-
ture of the crater. It might be questioned whether there is energy
enough in the current to do all this work, but upon an extravagant
estimate of the amount of carbon volatilised in the crater, it appears
that there is more than a hundred times as much energy supplied by
the current as would be required for volatilising the carbon, even
though its latent heat were as great as the heat of combustion of C
into CO2.
There is another considerable difficulty in the theory of the tem-
perature of the crater being that of boiling carbon arising from the
slowness of evaporation. The crater on mercury is dark, but then it
volatilises with immense rapidity and the supply of energy by the
current being more than 100 times that required merely for evapora-
tion, there seems very little reason why even a considerable difference
in latent heat should make any sensible difference in the rate of
evaporation of mercury and carbon, especially as, at the same tem-
perature, the diffusion of carbon vapour is nearly three times as fast
as that of mercury vapour and the temperature immensely higher.
We would, in conclusion, call attention to a cause of opacity in
the solar atmosphere that is illustrated by the effect of convection
currents in the long tube we were observing at high pressures ; these
convection currents behaved just like snow, or any other finely divided
transparent body immersed in another of different refractive index.
Light trying to get through is reflected backwards and forwards in
every direction, until most of it gets back by the way it came. The con-
sequence was that even the electric arc light was unable to penetrate
the tube at high pressure, when these convection currents were active.
The only light that came out of the tube was the feeble light outside,
which was returned to us by reflection at the surfaces of these con-
vection currents. In a similar manner we conceive that any part of
the solar atmosphere which is at a high pressure, and where convec-
tion currents, or currents of different kinds of materials, are active,
would reflect back to the sun any radiations coming from below, and
reflect to us only the feeble radiations coming from interplanetary
space. In his paper on " The Physical Constitution of the Sun and
Stars " (' Roy. Soc. Proc.,' No. 105, 1868), Dr. Stoney called attention
to an action of this kind that might be due to clouds of transparent
Influence of Temperature upon Electrotonic Currents. 383
material, like clouds of water on the earth, but in view of the high
solar temperature it seems improbable that any body, except, perhaps,
carbon, could exist in any condition other than the gaseous state in
the solar atmosphere ; so that it seems more probable that sun-spots
are due, at least partly, to reflection by convection streams of gas,
rather than by clouds of transparent solid or liquid particles.
" Influence of Alterations of Temperature upon the Electro-
tonic Currents of Medullated Nerve."* By AUGUSTUS D.
WALLER, M.D., F.R.S. Received December 14, — Read
December 17, 1896.
(Abstract.)
The effects of a rise of temperature upon electrotonic currents
may be briefly stated as follows : —
1. The ordinary electrotonic currents, A and K, are temporarily
diminished or abolished at about 40°.
2. At about 30° of a rising temperature the K current is increased
without notable alteration or with actual diminution of the A current.
3. On returning from 40° towards the normal (15° + 2°) tempera-
ture, the A and K currents reappear. K is increased and A is
diminished, so that the previous normal inequality A > K is
diminished, or actually reversed to A < K. In all cases the quotient
A/K is diminished ; in some cases it actually falls below unity.
[The negative variation is temporarily abolished at about 40° ; a
positive gives place to a negative variation in consequence of a
raised temperature to 40°.]
The above three statements are illustrated by Experiments 2366,
2322, and, from the examination of their records, it will be clear
that there is here no question of the effects being due to alterations
of resistance. A and K are tested for alternately, and the deflection
by O'OOl volt is taken at intervals of about ten minutes. [Other
examples of a similar character are given in the * Proceedings of
the Physiological Society' for November, 1896, and a record of
temporary diminution of the negative variation is given in fig. 12
(Experiment 777), * Phil. Trans.,' 1897.]
* In all the experiments referred to in this communication, the polarising cur-
rent is by one Leclanche cell (the resistance in its circuit being about 100,000
ohms). The nerve lies upon four unpolarisable electrodes fixed at intervals of
12 mm., serving as leading-in electrodes to the polarising current and leading-out
electrodes to the electrotonic current. On the galvanometer records, the anelectro-
tonic deflection A reads upwards, the katelectrotonic deflection K reads downwards ;
aiter-anelectrotonic and after-katelectrotonic deflections A' and K' read respectively
downwards and upwards (there being under the conditions of experiment no
marked homodromous after-katelectrotonic deflection).
384
Dr. A. D. Waller- Influence of Alterations of
Exp. 2322. — Influence of raised Temperature upon Anelectrotonic and
Katelectrotonic Currents.
Time.
Tempera-
ture.
A. A'.
K. K'.
TO'TTO volt.
i
i
Omin.
17°
_ 1 _
_
__
9
1
5)
+ 12 -2
—
—
2
J>
— —
— trace
+ 2
5
>>
+ 12 -2
—
—
6
>>
—
—
— trace
+ 2
fio
21
+ 12-5
-2-5
11
—
—
—
— trace
+ 3
15
30
-5
-t-3-5
•§' j 16
+ 11-5
-5
—
|| 20
38
+ 3
—
—
— .
21
39
—
—
i
—
25
39
—
—
-2 —
L26
38-5
+ 3
—
— —
30
35-5
+ 5
-1-5
.
31
35
—
—
-3-5 +0-5
40
28
+ 8-5
-2-5
— —
41
—
—
—
-4-5 +1
50
24
+ 8-5
-2
— —
51
—
—
—
-4-5 +1
52
~
_—
—
9
The K current is very small, the K' after-current is comparatively large. In
consequence of heating to 39'5°, K is increased, A and K' are diminished. The
quotient A/K is diminished.
m&w *
Temperature upon Klectrotonic Current*.
385
Exp. 2366. — Influence of raised Temperature upon An electro tonic
and Katelectrotonic Currents.
Time.
Temperature.
A. K.
T5U VOlfc.
0 min.
16°
_
_
8
1
V
+ 11-5
—
2
?>
—
-4-5
7
+ 11 -5
—
8
»
—
-4
f!2
19
—
—
8
114
22-5
+ 12
—
15
24
—
-4-5
16
26
-12
—
Hi 17
fills
28
29-5
n-11
-5
119
31-5
—
—
20
33
+ 10
—
21
35
—
-5
125
40
+ 2
—
26
40
1-5
30
36
+ 4
—
31
35
—
-4
32
34
—
—
10
33
33
+ 4
—
34
32
—
— 7
42
26-5
—
—
7
43
26
_
-8-5
44
25-5
+ 6-5
52
22-5
—
—
6-5
53
22
+ 6
—
54
22
—
-6
After heating to 40° the A current is diminished, the Jv current is increased, and
well-marked A' after-current has developed. The quotient A K is diminished;
386
Dr. A. D. Waller. Influence of Alterations of
Electrotonic after-currents, A' and K', when present to any marked
degree, are opposed to the previous electrotonic currents A and K.
Designating A and K respectively as positive and negative, the
after-currents A' and K' are respectively negative and positive. Such
after-currents are in general modified by previous rise of tempera-
ture, which gives rise to an evident A' (negative) in a nerve which
previously gave no marked A', and abolishes a K' (positive) that
may previously have been present. Experiment 2366 exhibits the
development of an evident negative A' subsequent to heating of the
nerve. Experiment 2322 exhibits the abolition of a positive K',
evident previous to heating of the nerve.
A fall of temperature causes an increase of the A current and,
in less degree, of the K current; by reason of the diminution of
resistance that takes place with lowered temperature, the increase of
A is more marked than is apparent upon the record, and the smaller
increase of K is quite masked by the diminution of resistance. The
quotient A/K is augmented. At a temperature of —4° to —6° both
currents are somewhat suddenly abolished ; this abolition may be
complete and final, no recovery taking place, or it may be temporary,
being succeeded by imperfect recovery as the nerve temperature
returns towards normal. It is noteworthy that the A and K currents
are not abolished at 0° suddenly, and all but finally abolished at — 4°
Temperature upon Electrotonic Currents.
387
to —6°, probably by reason of the nerve having been frozen at this
temperature and thus cut to pieces.
It is evident that little stress is to be laid upon an apparent
decrease of K with falling temperature (2417) and increase of K
\vith rising temperature (2366). On the other hand, a diminished
A with rising temperature (2366) and an increased A with falling
temperature (2417) are not open to doubt.
Exp. 2334-5.— Influence of lowered Temperature upon Anelectrotonic
and Katelectrotonic Currents.
Time.
Temp.
A.
K.
ToW v°lfc-
0 min. 17°
__
__
9-0
1
+ 11-5
—
2
—
-2-5
7
+ 11-5
—
8
M
—
-2-5
r 9
]
+ 11-5
—
10
16-5
—
-2-5
17
15
+ 11-5
—
18
]4'5
—
-2-5
27
8
+ 12
28
7'5
—
-2-5
2 J 37
3
+ 12
0 I38
2-5
—
-1-5
47
-0-5
+ 10-5
—
48
-0-5
—
-1
56
-3
—
-0-5
57
-3
+ 6-5
58
-3-5
—
—
3-5
.67
-4
0
—
68
-4
0
77
+ 1-5
0
—
78
+ 2
—
0
80
4
—
—
3-5
87
6
•4- 2
—
88
6
—
— trace
98
9
+ 3-5
99 9 -5
-0'75
108 11
+ 3-5
—
109 11 "5
—
-1
116 12
—
—
4-5
180 14
+ 4
-2
6-0
i
Influence of Temperature upon JZlectrotonic Currents. 389
Expt. 2417.— Effect of Cold on A and K,
Time.
Temperature.
A.
K.
A/K.
ToVo volt.
0
15°
_
7-5
1
—
-4
2
j>
+ 13
—
3-25
7
5»
—
-4
—
8
'5
+ 13-5
— .
3-37
11
14
—
^
12
—
+ 14-5
3-62
13
—
. —
-4
14
12-5
+ 14-5
—
3 62
15
—
—
-3'5
16
11
+ 15
4-28
17
—
_
-4
18
9
+ 15-5
—
3-87
21
6
—
—
5*5
23
4
—
-3-5
24
3
+ 16 5
. .
4-71
27
2
—
-3-5
28
1-5
+ 16-5
4-71
29
— !
—
-3
_
30
0-5
4 17
—
5-66
32
—
_
4-5
33
-0-5
+ 16-5
—
34
—
—
-3
—
35
1
+ 17
—
5-66
36
—
-2-5
37
-1-5
+ 17
- —
0-8
38
—
-2-5
39
— 2
+ 17'5
—
7
40
—
—
-2-5
41
-2-5
+ 17
—
6-8
42
—
—
-2-5
—
43
-3
+ 17
—
6-8
44
—
—
-2
— -
45
-3
+ 16-5
—
8-25
48
—
—
-2
—
49
-3-5
+ 16-5
8-25
52
L
—
4
The A effect obviously increases with fall of temperature (increasing resistance) j
the K effect apparently diminishes, but actually increases a little, the increase
being masked by increased resistance. The A/K quotient is obviously increased.
The voltage calculated from the data of this experiment is : —
At 15° A = 0-00173 volt. K = 0-00053 volt.
10
5
0
A = 0-00244
A = 0-00285
A = 0-00360
K = 0-00059
K = 0-00064
K = 0-00070
Dr. A. U. Waller. Influence of Alterations of
Exp. 2344. — Influence of Alterations of Temperature upon the
Electrical Resistance of Nerve.
The following experiment (2344) made to test the effect of rising
and falling temperature upon the electrical resistance of nerve, and
the value attaching to observations of a standard deflection by
constant E.M.F. as an indication of altered resistance, shows very
Temperature upon Electrotonic Currents.
391
clearly that such standard deflection gives measure not only of the
electrical resistance, but also — due reservation being made of the
effect of drying in the course of a prolonged observation at raised
temperature — is itself available in measure of the alteration of tem-
perature of the nerve.
Exp. 2344.— Deflections by a small constant E.M.F. (O002 volt)
through a .Nerve at rising and falling Temperature and through
two Galvanometers.
Time.
Thermometer.
Demonstrating
galvanometer, G-J.
Recording
galvanometer, OK.
1 min.
16-5°
18-5 c m.
14 -0 mm.
5
16*5
18-5
14-0
10
18-0
19'5
15'()
15
24-0
21-5
17 0
20
30-5
25-5
20-0'
25
35-5
28-5
23-0
30
39-0
30-0
23-5
35
40-0
30-0
24-5
40
38-0
29-0
23-0
45
33-0
26-0
20-0
50
28-0
22-0
17-0
55
25-0
20-5
16-0
60
23-0
19-0
15-0
40"
35°
J0°
« /ncremente of GemperaCurs
- increments of o'ef/ecC/on read upon Gf.
n >• " measured from the record of G2 .
G,
50
JO 15 20 25 JO 65 4O
50 55 60 mm.
[Experiments on the comparative effects of acids and bases upon
the A and K currents, have shown that within a certain moderate
range of concentration (soakage of the nerve in n/15 to nj^O solution
for one minute) acid favours the K current and disfavours the A
392 Influence of Temperature upon Electrotonic Currents.
Re
experi
in
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1
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+ + +
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a I •*! i=r b* T 1
s
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Oil the Occurrence of Gallium in Clay-ironstone. 303
current, giving decrease of the quotient A/K; while base favours the
A current and disfavours the K current. In other words, the anodic
or acidic polarisation is favoured by base, disfavoured by acid; the
kathodic or basic polarisation is favoured by acid, disfavoured by base.
Anaesthetics (C02; Et^O ; CHC13) act like acids and like rise of tem-
perature, causing, at certain strengths, a greater relative diminution
of A than of K, and therefore a diminution of the quotient A/K — tem-
porary in the case of C02 and Et2O, permanent in the case of CHClo.
In the weakest dilution that will produce any effect at all there may
be increase of A, no increase, or a relatively smaller increase, of K,
and therefore increase of the quotient A/K. These effects are,
however, at present under examination, and will form the subject of a
future communication. The tabular summary (p. 391) will at this
juncture be sufficient to enable a comparison to be made between the
effects of heat and cold and those of acids and alkalies.]
" On the Occurrence of Gallium in the Clay-ironstone of
the Cleveland District of Yorkshire : Determination of
Gallium in Blast-furnace Iron from Middlesbrough." By
W. N. HARTLEY, F.R.S., Professor of Chemistry, and HUGH
RAM AGE, A.R.C.Sc.L, F.I.C., Assistant Chemist, Royal
College of Science, Dublin. Received December 2, — Read
December 17, 1896.
In the month of April of this year, we had the honour to submit
to the Royal Society* a preliminary notice of the evidence we had
obtained of the existence of gallium in the Yorkshire ironstone
smelted at Middlesbrough -on-Tees.
We propose now to give a concise but detailed account of the
methods of analysis carried out on the metal and the ore, and the
determination of the quantity of gallium present.
Examination of the Blast Furnace Metal.
Method of Analysis. — The very large proportion of iron rendered
the application of some special method of analysis necessary for the
separation of metals present in minute proportions, and for the quali-
tative and quantitative examinations of the separated substances.
We have successfully employed fractional precipitations and the.
spectrographic analysis of the precipitates, supplemented by gravi-
metric determinations of the purified gallium sesquioxide.
The sample of metal first received consisted of two small ingots,
each weighing about 230 grams ; small pieces, broken with difficulty,
* < EOT. Soc. Proc.,' vol. 60, p. 35, 1896.
VOL. LX. 2 H
394 Prof. VV. N. Hartley and Mr. II. Ramage.
from these and heated in the oxyhydrogen flame, gave the gallium
line \ 4171/6. The ingots were exceedingly hard, and practically
resisted all attempts to reduce them to small pieces. One ingot,
weighing 210 grams, was boiled with hydrochloric acid, until its
solvent action on the metal had nearly ceased, when the liquid was
decanted, and fresh acid poured on. The process was very slow, and,
after 80 grams had been dissolved, the remaining piece of metal was
scraped, to remove an adhering layer of carbonaceous matter, and
the analysis of the products proceeded with. The liquid was filtered,
and the black residue A washed. The filtrate was evaporated, to
expel the excess of hydrochloric acid, water was added, and the solu-
tion, not being clear, was filtered. The residue B thus obtained had,
when dry, a dark greyish colour. Residues A and B.
In the clear filtrate two rods of zinc were immersed, and during a
period of one hour and three-quarters hydrogen was evolved, and
metals were deposited on the zinc. The deposit was scraped off, and
separated from the liquid by filtration. Metallic deposit G. To the
filtered solution were added about 4 c.c. of lead acetate solution, and
two rods of zinc were placed in the liquid, according to the method
of Lecocq de Boisbaudra.n,* by which, as the lead is precipitated,
traces of other metals, such as copper, silver, indium, thallium, &c.,
are collected by the lead. Metallic precipitate F.
Fractional Precipitation by Ammonium Acetate. — The filtrate, in
volume about 2 litres, was boiled, but as no precipitate formed, 15 c.c.
or thereabouts of a solution of ammonium acetate were slowly added,
and the solution boiled ; the iron, being in the ferrous state, was
retained in solution, whilst it was expected that the gallium would
be precipitated as phosphate. After boiling for about twenty minutes,
the substances precipitated were collected on a filter and washed.
Residue D.
The filtrate was again boiled with about 10 c.c. of ammonium
acetate, and the precipitate collected on a filter. Residue E.
Further Precipitation of Basic Acetates. — The filtrate from E was
again boiled with ammonium acetate, the resulting precipitate being
filtered off. It was much darker in colour than those previously
obtained. Sesquioxide metals G.
The filtrate was evaporated until it became a saturated solution of
ferrous chloride. It was allowed to cool and crystallise, and the
operation was repeated upon the mother liquor. The two crops of
crystals were mixed with others, which were obtained as follows.
The solution from the remaining portion of the 210 grams of
metal was filtered, and the filtrate evaporated. It was then allowed
to cool and crystallise. The mother liquor was concenl rated, and
again allowed to cool and crystallise, the different crops of crystals
* ' Spectres Lumineux.'
On the Occurrence of Gallium in Clay -ironstone. 395
being collected. The mother liquor from the last crop of crystals
was evaporated almost to dryness to expel acid, and, after addition
of water, rods of zinc were immersed in the solution, which was
then left undisturbed for forty-eight hours. The zinc was found to
have been almost all dissolved. The precipitated metals and the
residue of zinc were washed and dried. Residue H. The filtrate,
after three precipitations with ammonium acetate, was mixed with
the mother liquor of the ferrous chloride crystals from the first
portion, so that the liquid then represented the whole of the ingot.
It was diluted, mixed with an excess of ammonia and ammonium
sulphide, to precipitate all the iron and metals of that group still in
the solution, and filtered. The filtrate was evaporated to dryness and
gently ignited to expel ammonium salts. A residue was left, which
contained the alkaline earths and alkaline metals.
The Spectrographic Analysis of the Residues and of the Precipitates.
From the foregoing description it will be observed that by partial
solution the metals precipitable by iron may be looked for along with
carbon, and, probably, some phosphides of iron and other metals.
Such phosphides yield the flame spectra of the metals only, and not
of the phosphorus combined with them. Precipitation with zinc in
an acid solution was expected to give a deposit (F and JET) which
would yield the spectra of copper, silver, bismuth, lead, thallium, and
tin in the oxyh) drogen flame, if these metals were not already pre-
cipitated by the iron, and present in the residues A and B • while
D, E, and G are compounds which fall under the category of sesqui-
oxide metals, including beryllium, aluminium, indium, gallium, and
chromium. Of these, aluminium and beryllium were expected to
show no spectra in the oxyhydrogen flame, and for these it was
intended to use spark spectra.
The residue A, when dried in the water oven and gently heated,
gave off fumes which indicated that an oil was present, and extrac-
tion with ether and subsequent evaporation did, indeed, yield a
quantity of a brown oil.
The oxyhydrogen flame spectra of the substances separated were
photographed, and the following are particulars regarding their
spectra.
The insoluble residue A contained iron, manganese, copper, gallium,
sodium, chromium, silver, and nickel.
The lines which served to identify the metals had the following
wave-lengths : —
Iron .... 4308-0 4046'0 3929'8 3922-0 3904-8
3898-5 3886-5 3860-0 3857'0 3841-0
3834-0 3826-0 3824-5 3758-4
2 H 2
396 Prof. W. N. Hartley and Mr. H. Ramage.
and all the strong lines in the groups extending to 3441, correspond-
ing to the solar line 0.
Manganese .
Copper
Gallium ....
4033-0
3290-0
4171-6
4032-0
3262-5
4032-7
4030-0
- —
Sodium ....
5893-0
5688-0
4668-0
3303-0
Chromium. .
Silver • .
4289-0
3383-5
4274-0
3282-1
4253-0
3606-0
Nickel .,
3525-0
3415-0
__ ._,
3593-0 3578-0
The insoluble residue B contained iron, copper, sodium, and a trace
of potassium.
Iron Groups of lines lying between 4045'0 and 3440*0
Copper . . . Lines with wave-lengths 3290'0 „ 3262- 5
Sodium... „ ., .... 5893-0 „ 33030
Potassium „ „ 4047'! „ 4043'5
The metals precipitated l>y zinc, C. These were iron, copper, silver,
a trace of lead, also some sodium and potassium. There was also a
trace of chromium, and this, like the trace of iron, was probably pre-
cipitated as basic chloride or as hydroxide. The wave-lengths of the
lines of iron, silver, and copper need not be recapitulated.
Lead 4057 3682 and 3639
Chromium 4289 4274 „ 4253
The metals precipitated by zinc after addition of lead acetate, F. —
The metallic deposit yielded a complex spectrum containing the
lines already mentioned of the following elements : iron, chromium,
copper, silver, gallium (a trace), potassium, sodium, and, of course,
lead, as this had been added.
The lead here appears as a banded spectrum, the edges of the
bands seen being those at wave-lengths : —
5675 5460 4980 4824 4657
4597 4370 4314 4225 4140
4061 4057 3985 and 3954
Nickel lines. ... 3525 „ 3415
The copper lines were very strong, the silver weak.
The potassium lines were the following : —
4047-1 4043-5 strong,
then much fainter —
3447-5 and 3446'5.
On the Occurrence of Gallium in Clay -ironstone. 397
The precipitates of Phosphates and basic acetates D, E, and G.
Precipitate E.
Chromium 5206 4289'0 4274'0 4253'0
3606 3594 0 3579*0
Gallium strong 4171'6and 4032'7
(the latter somewhat weaker).
Calcium weak 4226'8
Potassium strong 4047'0 4043'5
Sodium strong 5893'0, faint 5635, and 3303'0
Precipitate D,
The chromium line 5206 did not appear in the spectrum of this
precipitate. Both the gallium lines were very distinct, 4171*6 and
4032-7.
It is remarkable how very generally the spectrum of potassium
appears along with that of the precipitated substances, whether
metals or basic acetates.
Precipitate of basic acetates, G.
This contained iron, chromium, lead, gallium, potassium, ami
sodium. The lines were those which have already been particu-
larised.
The Residue left by Zinc, H. — This was heated with aqua regia,
when all but a very small quantity of silica with a trace of a metallic
oxide dissolved. The liquid was filtered and the filtrate evaporated
with excess of hydrochloric acid to remove nitric acid. It was
diluted with water, when it showed a green colour.
It was saturated with sulphuretted hydrogen and filtered to
separate the precipitate. The precipitate was partially soluble in
sodium hydrogen sulphide, yielding a sherry-coloured solution ; the
constituent causing. this colour was not identified, the quantity
present being very small. The residue, insoluble in alkaline
sulphide, contained copper and a. trace of lead, but no mercury,
bismuth,' or cadmium.
The filtrate from zinc and precipitated metals J, was diluted and
heated to boiling. It gave a precipitate, and therefore ammonium
acetate was added to the hot liquid, and after boiling for several
minutes it was filtered. The filtrate became turbid immediately ; it
was then boiled and more ammonium acetate added and then filtered ;
the filtrate again became turbid.
This precipitate was filtered off and heated in the oxyhydrogen
flame.
It contained no gallium, but the spectrum gave lines of iron,
copper, sodium, potassium, and a .trace of lead.
It is evident that all the gallium was extracted by the repeated
additions of ammonium acetate solution and boiling.
398 Prof. W. N. Hartley and Mr. H. Ramage.
The various precipitates of basic acetates were mixed, with the
exception of that from 7, which contained no gallium. In order to
separate phosphoric acid, the precipitates were fused with about
three times their weight of mixed carbonates. Some potassium
nitrate was added towards the end of the fusion, to convert chromium
into chromates. The heavy metals were left as oxides or carbonates,
the phosphoric acid going into solution. After extraction with hot
water, the solution was filtered.
Filtrate L. Residue M.
Coloured greenish by man- Dried and fused in a silver dish
ganates, boiled -with a few drops with caustic soda to dissolve
of alcohol to separate manganese gallium hydroxide. Extracted
as hydroxide. Solution, after with water and filtered. Residue
again filtering from manganese, not examined further. Solution :
was yellow from chromates. acidified with HC1 and ammo-
nium chloride and ammonia
added. The precipitate was fil-
tered off, dissolved in HC1, and
sparked to observe its spectrum.
These gallium spectra showed that there were still traces of
chromium in the gallium chloride, and from this the gallium was
purified completely by precipitation in a strongly acid solution with
potassium ferrocyanide and subsequent removal of the iron by treat-
ment with sodium hydrate, according to the method of Lecocq de
Boisbaudran.*
The foregoing description of the analytical details proves the
presence of gallium in the metal, and gives a clear indication of how
it may be separated by a simple process.
In subsequent operations on the blast-furnace metal, the ferrous
chloride was mixed with calcium carbonate, and the gallium was
found to be all precipitated and capable of easy separation 'from the
calcium salt.f Latterly it was found i.o be more convenient to boil
the acid solution containing gallium with an excess of the iron under
examination, and thus the gallium is concentrated in the residue
T?hich remains un dissolved.;]:
It became necsssary to consider what was the source of the gallium
contained in the iron. Was the gallium concentrated in the metal ?
Or did it pass into the slag of the converter? Was it originally con-
tained in the ore, the lime, or the fuel ? Was it easily volatilised, so
as to pass off with fume or with flue dust ?
* ' Comptes Rendus,' vol. 94, p. 1228.
t Loc. cit., p. 1629.
| ' Comptes Rendus,' vol. 49, p. 1625.
On the Occurrence of Gallium in Clay-ironstone. 399
On February 10th we received from Mr. C. R. Ridsdale, the
Chemist, at the North Eastern Co.'s Steel Works, at Middlesbrough,
samples of the following materials : —
1. " Mixer metal," i.e., mixed blast-furnace metal.
2. Roasted Cleveland iron ore.
3. Flue dust.
4. Tap cinder.
5. Manganese ore.
6. Lime.
On February 12th, photographs of the oxy hydrogen flame spectra
of these substances were obtained.
The following are the particulars of this examination : —
1. The roasted Cleveland ore contained iron, sodium, potassium,
manganese, chromium, nickel, copper, gallium, lead, and
calcium.
2. The blast-furnace metal contained iron, sodium, potassium,
manganese, nickel, copper, gallium, and lead.
3. Flue dust contained iron, sodium, potassium, manganese,
chromium, nickel, copper, silver, gallium (doubtful), lead
(strong), calcium, and rubidium. Rubidium was identified
by the lines 4202 and 4216. (Thalen.) Calcium by line 4226,
in the blue.
It is evident now that gallium is contained in the ore and is con-
centrated in the metal.
1. The manganese ore (a 15 per cent. Spanish ore) contained
iron, sodium, potassium, manganese, copper, silver, lead,
indium, and calcium. The lines by which the indium and the
silver were identified are as follows : —
Indium 4510'2 4101-3
Silver 3383-5 3282-1
The occurrence of indium is remarkable, as hitherto it has been
found only in zinc blendes.
2. Tap cinder contained iron, sodium, potassium, manganese,
copper, and lead.
3. Lime contained calcium, magnesium, potassium, and sodium,
a trace of iron, and a trace of manganese.
The lime showed the following bands, characteristic of lime* :— -
Band in the orange from 6253 to 6116, degraded towards the
more refrangible side.
Band from 6075 to about 5900.
* ' Phil. Trans.,' vol. 185, p. 182.
400 Prof. W. N. Hartley and Mr. H. Ramage.
Very strong band from 5598 to 5485.
Band of continuous rays with other bands discernible in it.
Less refrangible edge of band 5445.
Band in the same at 5422, 5390, 5359, 5341, 5322.
The more refrangible edge of band 5304.
Very narrow band in the blue, more like a very strong broad line
from 4222 to 4215.
The magnesium oxide was identified by three bands, more or less
connected by diffused rays.
1st. From 3929 to 3856
2nd. „ 3834 „ 3805
3rd. „ 3805 „ 3682
On these bands were seen ten iron lines, six in the first principal
group and four in the second, all very faint, but with apparently the
following wave-lengths, which correspond wiih the lines seen in
oxyhydrogen flame spectrum of ferric oxide. They are also closely
in approximation to, and probably identical with, the following arc
lines, measured by Kayser and Runge in iron.
3860-03 3856-49 3826-04 3824-58
3758-36 3748-39 3745-67 3737-27
3735-0 3722-69 3720-07
Roasted Cleveland Iron Ore. Process for the Extraction of Gallium.
This ore is a complex substance, and contains elements which
render the complete extraction of the gallium very difficult. It is in
great part soluble in strong hydrochloric acid, but the iron goes into
solutions as a ferric salt, and difficulties arise in attempting to reduce
it to the ferrous, state. Zinc and iron are both liable to contain
gallium, and, without a very careful examination of a quantity of
the metal, it would be wrong to use them as reducing agents, seeing
that the quantity of metal required in the process is large in com-
parison with the sample treated. Sulphurous acid and kindred sub-
stances yield sulphates which cause a quantity of the alkaline earths
to separate as sulphates, and, as these precipitate in faintly acid solu-
tions, there is a risk of basic gallium sulphate being carried down
with them.
Dilute hydrochloric acid yields a solution poor in iron, but the dis-
solved matter is richer in gallium than the original ore. A large
proportion of silicic acid is, however, contained in the solution.
Experiments were made on quantities of 50 grams of the ore, and
the spectra from the sesquioxide metals were carefully compared
with the spectra from the similar products from the metal, and we
find that, as in the comparison of the original samples of ore and
On the Occurrence of Gallium in Clay-ironstone. 401
metal, the gallium lines are decidedly stronger in the spectra of
the substances extracted from the metal.
One kilo, of finely powdered ore was mixed with dilute hydro-
chloric acid of double normal strength, measuring about 1250 c.c.
Some carbon dioxide was disengaged and an insoluble residue left
.which was removed by filtration. The filtrate was then heated when
a gelatinous separation of silica occurred. After evaporation to
dryness, a further addition of hydrochloric acid yielded a solution
which was not highly coloured, and, presumably, did not contain
much iron. The silica rendered insoluble was removed by filtration,
and to the filtrate ammonium chloride and ammonia were added.
The precipitate thus formed was dissolved in hydrochloric acid,
reduced with sulphur dioxide, nearly neutralised, and boiled with
sodium thiosulphate. The precipitate was dissolved in hydrochloric
acid and again precipitated by ammonia.
This precipitate was examined for gallium. The insoluble residue
was also examined, and a comparison of the two spectra showed that
a larger quantity of gallium remained in the insoluble residue than
was extracted by the acid. It was found that gallium could be
.extracted from this by fusion with caustic soda and lixiviation with
water, and that the residue, after such treatment, contained no
gallium. Operations on this particular ore were suspended until
other samples had been examined. ,
The following ores from the collection in the Royal College of
Science, Dublin, were examined: —
1. Yorkshire clay ironstone from near Middlesbrough.
2. Clay ironstone from Grosmont, Whitby, Yorkshire.
3. Northamptonshire ore (clay ironstone).
4. Black band ore, Mount Melville mine, St. Andrews.
One kilo, of each was reduced to fine powder, and 100 grams of
Nos. 1, 2, and 3, and 500 grams of No. 4 were extracted with dilute
hydrochloric acid as in the previous case. In each sample gallium
was found, but the proportion was very small in the Northampton-
shire ore, and still more minute in the black band. Without operat-
ing on several hundred grams it would have been scarcely possible to
detect the gallium in the Mount Melville ore. These ores had not
been roasted, and in this they differed from the sample received from
the North Eastern Steel Works. The effect of roasting is the same
as increasing the proportion of gallium in the ore.
Estimation of Gallium in the Blast Furnace Metal from Middlesbrough.
The sample weighing 575 grams consisted of 155 grams of fine
powder and 420 grams of coarse powder. The latter portion was
heated with hydrochloric acid until the acid was nearly neutralised,
when the liquid was decanted and filtered.
402 Prof. W. N. Hartley and Mr. H. Ramage.
Residue A. Solution B.
The residue A was heated with hydrochloric acid to which a small
quantity of nitric acid was added from time to time ; the solution was
diluted and filtered.
Residue C. Solution D.
Residue G. — Dried and heated 0*5 gram in the oxyhydrogen flame.
The lines of gallium, chromium, nickel, and iron are strong, and lines
of sodium, manganese, potassium, copper, and silver are also present.
Solution J3. — Boiled for two hours with part of the finely powdered
sample added gradually to neutralise all the free acid, so that the
gallium in the solution might be precipitated as a basic salt.* The
solution was decanted and filtered. The residue was boiled with
solution D, to which the remainder of the finely powdered sample
was slowly added ; after boiling for several hours the solution was
filtered, and the residue F washed with water. The filtrate was
mixed with that from solution J>, the mixture forming solution G,
which should be free from gallium. This solution was boiled with
freshly precipitated copper hydrate,! and the precipitate examined
spectrographically for gallium. It contained none.
Residue F. — Boiled with an excess of hydrochloric acid, diluted,
filtered, and washed, Residue H. Filtrate I.
Residue H. — Dried, powdered, and mixed with residue C. Gentty
heated, the mixture decomposes and expels hydrocarbons, causing
the mass to ignite and evolve some white fumes. The substance
was thus seen to be very inflammable, and the temperature was
reduced as quickly as possible. When cold, it was covered with
aqua regia and heated on the water bath for several hours, then
diluted and filtered. Filtrate added to J, forming solution K.
Residue L.
Residue L. — A small quantity of it was heated in the oxyhydrogen
flame. The gallium line is strong. 45 c.c. of strong sulphuric acid
was heated in a porcelain basin until it gave off white fames; the
residue was then added forming a pasty mass which was kept hot for
about three hours ; white fumes being emitted during the whole time.
Water was then added, and the liquid filtered. Filtrate N. Resi-
due M. A portion of the latter was heated in the oxyhydrogen flame.
The gallium line is still present.
Besides the small quantity remaining in the residue M, the gallium
should now be in the solutions K and N. Solution K was evaporated
nearly to dryness to expel the excess of acid, then diluted, saturated
with sulphur dioxide, nearly neutralised with ammonia, and boiled to
* ' Comptes Rendus,' vol. 93. p. 818. See also a complete account, ' Separa-
tion du Gallium d'avec les autres elements,' par M. Lecocq de Boisbaudran. Paris,
Oautbier- Villain. 1884. Reprinted from the ' Annales de Chimie,' 6. Serie, t. 2.
f ' Comptes Rendus,' vol. 94, p. 1154.
On the Occurrence of Gallium in Clay-ironstone. 403
reduce the iron to the ferrous state. This operation was unsuccessful,
a quantity of iron remaining in the ferric state. The solution N
was, therefore, added and the mixture evaporated that the moro
volatile acids might be expelled by the sulphuric acid. On adding-
water to the residue a small quantity of matter remains undissolved ;
it was removed by filtration. Residue M?.
Up to this stage no reagent had been used which was likely to
contain gallium, and we had to consider which of the processes
known to separate gallium would be suitable under the conditions of
our analysis. The simplest would have been to boil with iron or zinc,
but gallium is found associated with both of these metals, and it was
decided not to use them. Precipitation by barium carbonate would
have been easily effected if sulphuric acid had not been present in
such quantity. Bat, to avoid inaccuracy, the best — although more
troublesome process — seemed to be the precipitation of the phos-
phates of the sesquioxide metals in an acetic acid solution, there
being phosphoric acid already in the liquid. The precipitates should
contain all the gallium, chromium, and aluminium as phosphates and
some phosphate of iron. The gallium is easily separated from
chromium and iron by fusion with caustic soda, and from phosphoric
acid, aluminium, and chromium by precipitation with potassium
ferrocyanide.
The iron was first reduced by passing sulphur dioxide into the
solution until it became strongly charged, and heating to boiling,
with addition of ammonia, to neutralise the excess of free acid. The
addition of ammonia was continued until the white precipitate which
formed remained undissolved after boiling for two or three minutes.
Boiling water was then added to make the volume of the solution
about four litres; this dilution caused a large quantity of light
coloured precipitate to form. Ammonium acetate was added, and
the liquid, after boiling for several minutes, filtered.
Residue 0. — The filtrate was boiled and ammonium carbonate
added until a quantity of pale, greenish -coloured precipitate was
deposited. More ammonium acetate was added, and the liquid,
still acid with acetic acid, was filtered. Residue P.
The process just described was repeated with the filtrate, the pre-
cipitate R being slightly darker than P. Filtrate Q,
Small quantities of the three residues, 0, P, R, were examined
spectrographicaily. The gallium lines are strongest in R. The
filtrate Q was again boiled with addition of ammonium carbonate to
neutralise some of the excess of acid, and the precipitate S, small in
quantity and of a dark green colour, was removed by nitration. It
contained only a trace of gallium.
The precipitates 0 and S, containing a much larger proportion of
iron than P and R, were dissolved in hydrochloric acid, and the
404 Prof. W. N. Hartley and Mr. H. Ramage.
gallium, &c., precipitaied, after reducing the iron to the ferrous
state. First precipitate, U. The second contained some gallium ;
the third, very dark in colour, was free from that metal.
The precipitates P, R, and U were dissolved in hydrochloric acid ,
and the solutions filtered to remove a small quantity of insoluble
matter which was added to residue M. Two drops of violet-coloured
filtrate were tested with potassium ferrocjanide, and so marked was
the reaction that it was decided to repeat the process of reduction and
precipitation to remove as much iron as possible. The first precipitate
W contained nearly all the gallium ; the second contained a small
quantity, and the third contained none.
The first and second precipitations Z7, whose spectra are seen in
1341 and 1343, contain a small quantity of gallium. They were redis-
solved, reduced, and boiled with excess of ammonium acetate, and the
precipitate collected. A second precipitate was free from gallium.
The former was fused with caustic soda, extracted with water and
filtered. The filtrate was acidified wihh hydrochloric acid, and boiled
with ammonia for some time, and the gallium phosphate thus pre-
cipitated was collected. This precipitate was added to W.
Residue W, Sfc. — This contained principally gallium and chromium
phosphate with some iron phosphate. It was dissolved in hydro-
chloric acid, and the solution made to contain about one-fourth its
volume of strong hydrochloric acid. Potassium ferrocyanide was
added, but not an excess, and the bulky precipitate collected. An
excess of the reagent was added to the filtrate, which, after standing
twenty-four hours, was filtered. Very small quantities of the two
precipitates were examined spectrographically ; the second is decidedly
richer in gallium than the first.
Residues M and M'z with the small Residues added to them as
described. — Ignited at a red heat to burn combustible matter. The
mass became grey and weighed, when cold, 8 grams. It was very
bulky, and consisted largely of silica. Fusion with fusion mixtures
converted the silica into alkaline silicates, which were removed by
solution in water, leaving a black residue. This was fused with
caustic soda and sufficient nitre to oxidise the graphite, &c. Water
dissolved all of this, excepting a small quantity of red oxide of iron,
part of which was examined for gallium. None present.
The filtrate was acidified with hydrochloric acid, evaporated to
dry ness, and dried at 120° C. to dehydrate silicic acid.
The dry residue was digested with strong hydrochloric acid, and
water added. It was then filtered to remove some silica, which was
found to have retained only a trace of gallium.
The filtrate was mixed with a small excess of ammonia, and boiled
•for some time; the gallium being precipitated probably as phosphate.
The filtrate in this and in all similar cases was again boiled, after
On the Occurrence of Gallium in Clay-ironstone. 405
adding a few drops of ammonia; if any precipitate was produced it.
was collected and added to the other precipitate. The precipitate in
this case was added to ferrocyanide precipitates obtained from the
residue W. The paper, after being scraped to remove the residue as
far as possible, was burnt in the oxyhydrogen flame. The gallium
lines are strong.
The ferrocyanide precipitates with others rich in gallium were
ignited at low redness to decompose the cyanides, and then fused
with pure caustic soda. The produce was extracted with water and
filtered.
Residue from Fusion. — Dissolved in hydrochloric acid, expelled the
excess of acid, added water, reduced the ferric salt, and filtered.
Residue remaining contained only a trace of gallium.
Filtrate. — Boiled with an excess of ammonium acetate and filtered
off the precipitate. The filtrate was mixed with sodium phosphate and
boiled, thus yielding a second precipitate. The filtrate from this was
again boiled, and ammonium carbonate added until a third precipitate
was produced. Very small portions of these three precipitates were
burnt in the oxyhydrogen flame. The first two were rich in gallium,
while the third contained only a trace. Ignited the first and second
precipitates, heated the residue in a platinum crucible with hydro-
chloric and sulphuric acids, expelled the former acid by heating until
the white fumes of sulphuric acid were evolved, and then fused the
residue with caustic soda. Extracted with water and filtered. After a
second fusion the residue was practically free from gallium. The
alkaline filtrates were acidified with hydrochloric acid, and the
gallium precipitated by boiling with ammonia until the excess ot
ammonia was expelled. Filtered and tested the filtrate by repeating
the process of boiling with ammonia until no further precipitate
resulted.
The precipitates of gallium hydrate and phosphate, obtained as
described, were dissolved in hydrochloric acid and, after adding one-
fourth the volume of the solution of strong hydrochloric acid, an
excess of potassium ferrocyanide was added. After standing for one
day the precipitate was collected, washed, and ignited. It weighed
0-0670 gram.
This residue was dissolved by heating with strong sulphuric acid
in a platinum crucible, some water being added, after heating strongly,
and then an excess of caustic soda prepared from sodium. The
crucible was then heated until the water was expelled, and the residue
retained in the fused caustic soda. The process was repeated on the
residue which remained after adding water and filtering. The second
residue was practically free from gallium.
The filtrates were collected in a platinum basin, made faintly acid
with hydrochloric acid, and saturated with sulphuretted hydrogen.
406 Prof. W. N. Hartley and Mr. H. Ranmge.
A brownish coloured precipitate was removed by filtration. It con-
tained copper, lead, and silver, but no gallium. The nitrate was
boiled to expel sulphuretted hydrogen, and the gallium precipitated
with ammonia as described above. The precipitate was collected and
ignited. It weighed 0*0288 gram.
This residue possessed a very light yellow colour. One milligram
was burnt in the oxyhydrogen flame ; its spectrum shows the two
gallium lines very strongly. Lines of sodium, potassium, iron, calcium,
and lead are present, but those of the last three are exceedingly weak.
The remaining 0*0278 gram of residue was fused with hydrogen
potassium sulphate ; water and sulphuric acid were added, and the
crucible heated until fumes of sulphuric acid were evolved. Water
was again added, and a small residue removed by filtration. This
residue weighed 0*0040 gram.
The gallium was separated from the iron by two extractions with
caustic soda solution. The ferric hydrate was dissolved in. hydro-
chloric acid, and reprecipitated by ammonia. The ferric oxide
weighed 0*0022 gram.
The gallium in the nitrate was then reprecipitated and weighed as
oxide. It weighed 0*0213 gram.
A few drops of sodium phosphate were added to the filtrate, and
sufficient ammonia to make it turn red litmus paper blue. After
boiling for a few minutes the liquid was filtered, the paper being
dried and burnt in the oxyhydrogen flame. The gallium lines are
present in its spectrum, but are very weak.
The oxide of gallium now possessed a scarcely perceptible, faint
yellow colour. It does not. represent the whole of the gallium present
in the sample, as a small quantity was removed and lost in testing
the precipitations and residues. We are able, however, to estimate
this quantity by comparing the lines in the different spectra with
lines and spectra obtained by heating weighed quantities of gallium
oxide. In this way we estimate the total quantity of gallium to be
as follows : —
Pure oxide _____ ........ ....... . 0*0213 gram.
In 0*001 gram of impure oxide ---- 0*0008 „
In residue insoluble in HKS04 ---- 0*0004 „
In other substances ........... . ', . 0*001 „
Gas03, total ........ 0'0235 gram.
0*0235 gram of pure Ga203 contains 0*0175 gram of gallium,
equal to °'°175 * 1Q° = 0*00304 per cent.
575
One part of gallium is contained in 33,000 parts of ornde iron.
On the Occurrence of Gallium in Clay-ironstone. 407
An estimation of the gallium in the " mixer metal " had been at-
tempted in the spring of this year, but the separation was not as
complete as in the process just described. The figure obtained,
however, is so closely in accord with the above that we will briefly
describe the process and record the result.
The sample, weighing 340 grams, was boiled with hydrochloric acid
until the latter was nearly neutralised ; the solution was then
decanted, and fresh acid added to the residue. When the acid
ceased to have any marked action the whole liquid was filtered, and
the residue A washed, dried, and treated separately for the separation
of gallium.
Filtrate B. — From this filtrate gallium was precipitated by calcium
carbonate, but phosphates and sesquioxide metals, including
chromium, rendered the precipitate a too complex mixture, and we
had recourse to the ferrocyanide method.
The gallium was separated from the iron by pure sodium hydrate,
and finally precipitated as hydrate and ignited. The oxide weighed
0'0149 gram, and this amount corresponds to 0'0033 per cent, of
gallium in the sample or one part in 30,000 of the iron.
We know, by the spectrographic examination of the residues, &c.,
that the whole of the gallium was not obtained, and that the oxide
weighed was not quite pure gallium oxide, but with the experience
gained in this estimation we were able to make the more exact
analysis already described.
In conclusion, we may state that this blast furnace metal contains
more gallium than the richest source of that element hitherto known.
The mineral referred to is a zinc blende from Bensburg on the Rhine,
about eight miles from Cologne ; it is found in the Franzisca adit of
the Luderich mine. MM. Lecocq de Boisbaudran and Jungfleisch
extracted 62 grams of crude gallium from 4300 kilograms, or nearly
4^ tons of the ore ; this is in the proportion of 1 in 72,000, but they
believed the actual quantity present to be about 1 part of gallium in
50,000 of the ore.
We have recently discovered other sources of gallium, bat cannot
include the details of our later work in the present communication.
408 Prof. C. S. Sherrington. Examination of the Peripheral
January 21, 1897.
Sir JOHN EVANS, K.C.B., D.C.L., LL.D., Vice- President and
Treasurer, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The Right Hon. Sir John Eldon Gorst, a member of Her Majesty's
Most Honourable Privy Council, was admitted into the Society.
The following Papers were read : —
I. " On Cheirostrobus, a new Type of Fossil Cone from the Cnlci-
ferous Sandstones." By D. H. SCOTT, M.A,, Ph.D., F.R.S.
II. " Experiments in Examination of the Peripheral Distribution of
the Fibres of the Posterior Roots of some Spinal Nerves.
Part II." By C. S. SHEEEINGTON, M.D., F.R.S., Holt Pro-
fessor of Physiology, University College, Liverpool.
III. " Cataleptoid Reflexes in the Monkey." By C. S. SHERRJNGTOX,
M.D., F.R.S., Holt Professor of Physiology, University
College, Liverpool.
IV. " On Reciprocal Innervation of Antagonistic Muscles. Third
Note." By C. S. SHERRINGTON, M.D., F.R.S., Holt Professor
of Physiology, University College, Liverpool.
" Experiments in Examination of the Peripheral Distribution
of the Fibres of the Posterior Roots of some Spinal Nerves,
Part II." By C. S. SHERRINGTON, F.R.S., Holt Professor
of Physiology, University College, Liverpool. Received
November 12, 1896,— Read January 21, 1897.
(Abstract.)
This paper is in continuation of one brought before the Society in
1892, and published in 'Phil. Trans.,' B, vol. 184. In that commu-
nication the peripheral distribution of the sensory nerve-roots of the
sacro-lumbar and the thoracic regions was examined. In the present
the examination is extended to the cervical and brachial sensory
Distribution of Fibres of Posterior Roots of Spinal Nerves. 409
roots, and to the skin distribution of the cranial nerves. The com-
munication is divided into four sections. In Section I the field of
peripheral distribution of each root is described from the Yth cervical
to the lower end of the brachial region. The description given is
taken in each case from one particular experiment, which has proved
a typical one for the root in question, and then deviations from this
type are appended to it in the form of annotations. Particular
attention was paid to the question of the skin-fields of the several
divisions, ophthalmic, maxillary, and inandibular of the cranial Vth,
in order to see if the fields possessed the characters of segmental
skin-fields, or those of peripheral nerve-trunk skin-fields. They
were found to conform with the latter, not with the former. A
curious relation of the posterior edge of the field of the Vth to the
external ear is found to exist, indicating that the position of the
visceral cleft is still adhered to as a boundary line for the field of the
trigeminus. The sense of taste as well as of touch is foand to be
destroyed in the anterior two-thirds of the tongue after intracranial
section of the Vth ; this makes it extremely doubtful whether the corda
tympani can have gustatory functions in the monkey, as has been
believed in some cases in man. No loss of eye-movements, or inter-
ference with them, has been found to result from intracranial section
of the Vth.
The results obtained on the various successive nerve-roots cannot
well be abstracted. The glossopharyngeal field on the tongue has
been successfully delimited.
After cranial Vth and all the upper cervical posterior roots have
been severed, there still persists a small field of sentient skin, which
includes the external auditory meatus and a part of the pinna. This
field, although not corresponding to the situation given by anthro-
potomists to the distribution of the auricular branch of the vagus*, comes
either from it or the glossopharyngeal. It presents interest as being
the only field representing the whole cutaneous distribution of an entire
nerve, which does not conform with the rules of zonal distribution
holding good in the case of each of the other nerve-roots examined,
and these now include the whole series. The posterior root of the
1st cervical nerve has a skin-field in the cat which includes the
pinna. The posterior root of the same nerve in Macacus has no
skin-field at all, its skin-field having apparently been included in the
Ilnd cervical of Macacus, not in the cranial Vth. The root fields con-
tributing to the surface of the brachial limb are Illrd, IVth, Vth,
Vlth, Vllth, and VHIth cervical, and 1st, Ilnd, and Illrd thoracic.
Of these, the VIII th cervical is the only one which includes the
whole of the surface of the free apex of the limb ; its distribution in
this respecb closely resembles that of the Vlth lumbar sensory root
in the pelvic limb.
VOL. LX. 2 I
410 Distribution of Fibres of Posterior Roots of Spinal Nerves.
The Ilnd section of the communication deals with the degree of
conformity between the distribution of the spinal ganglion fibres in
the skin and their distribution in the underlying deep tissues of the
limb. It is shown that, although the skin fields of the ganglia are
in the middle of the limb region dislocated from the median line of
the body, the distribution of the fibres of the root ganglion is never-
theless, when its deep distribution is taken into account, to a com-
plete ray of tissue extending in an unbroken fashion from the median
plane of the body oat along the limb to (in the case of the nerves,
extending farthest into the limb) the very apex of it. This distribu-
tion conforms, therefore, with that shown in a previous paper to be
typical of the distribution of the ventral (motor) root. The distinc-
tion is not, therefore, as between afferent and efferent, but as between
cutaneous and muscular. A detailed analysis of the distribution of the
deep sensory fibres is in this paper carried out for the YIth lumbar
spinal ganglion of Macacus rhesus ; this ganglion was chosen because
its skin-field, occupying the free apex of the lower limb, is one as far
dislocated from the median line of the body as any in the whole
spinal series, and presents, therefore, the greatest apparent discrepancy
between the distribution of its afferent and efferent roots. A com-
parison of the distribution of the afferent and efferent roots in this
(Vlth lumbar) nerve was made by means of the Wallerian method ;
the results show the peripheral distribution of the two to be minutely
similar. From this, and from other observations given, the rule is
put forward as a definitely established one that the sensory nerves of
a skeletal muscle in all cases derive from the spinal ganglion (or
ganglia) corresponding segmentally with that (or those) containing
the motor cells, whence issue motor nerve-fibres to the muscle. The
reflex arc, in which the afferent and efferent nerve-cells innervating
a muscle are components, need not, therefore, as far as anatomical
composition is concerned, involve irradiation through more than a
single spinal segment.
Section III deals with general features of arrangement recognisable
in the distribution of the roots ; for instance, the determination of
the position of the primary dorsal and ventral lines of the limbs,
the examination of the asserted rotation of the limbs and of the
asserted torsion of the limbs, and of the asserted homologies between
muscles, &c., of the brachial and pelvic limbs respectively, by the
criteria for re- examination of such questions provided by the facts
elicited in the course of the work ; the cross-lapping of the skin-
fields across the median line of the body, the overlapping of com-
ponent parts of a single field, the serial overlapping of adjacent fields,
the degree of overlapping in different regions of the body, the degree
of overlapping in peripheral nerve-trunk fields, the amount of over-
lapping of spinal ganglion-fields compared with that of peripheral
Cataleptoid Reflexes in the Monkey. 411
nerve-trunks, the comparison of sensory overlapping with motor
overlapping, the relation of overlapping to acuteness of sensation :
individual variation, its extent and frequency, as far as can be judged
from the skin-fields. Comparison between the human bracbial plexus
and that of Macacus is made, and it is pointed out that the human
plexus is slightly prefixed, as compared with that of Macacns.
Finally, in Section IV, " shock," and various spinal reactions are
examined, especially with reference to their effects upon the size and
other features of the areas of the root-fields, &c., and the results
collated and discussed.
" Cataleptoid Reflexes in the Monkey." By C. S. SHERRINGTON,
M.A., M.D., F.R.S., Holt Professor of Physiology, University
College, Liverpool. Received December 29, 1896, — Read
January 21, 1897.
A phenomenon came under my observation in the course of experi-
ments upon monkeys at the commencement of the present year
which seems sufficiently interesting to merit record here. Its occur-
rence, so long as certain conditions of experiment are maintained,
appears regular and predictable.
Although the character of the movements executed by the skeletal
muscles when excited reflexly through the medium of the isolated
spinal cord is variable, one feature common to them is their compara-
tive brevity of duration. Many of them are, as pointed out by Fick
and by Wundt years ago, hardly distinguishable in several particu-
lars from the simple twitches elicitable from an excised muscle, so
brief and local and inco-ordinate do they appear to be. Others are
more prolonged, and, as I have described in a paper recently com-
municated to the Society, exhibit various forms of sequence or
"march" (Hughlings Jackson). Without recapitulating the con-
clusions there drawn from the data given in that paper, I wish here
to merely point out that of movements due to purely spinal reflex
action, although some are fairly extensive, most are quite short-
lasting, and not so prolonged as the longer of those that can be
elicited under appropriate conditions from the cortex cerebri ; also
that if prolonged they, like the final phase of prolonged movements
initiated from the cortex, tend to become clonic, or to exhibit that
kind of action which in the paper referred to above I have desig-
nated "alternating."
The reflex movements, the subject proper of this note, are, on the
contrary, of extremely prolonged duration, and absolutely devoid of
clonic character and of alternating character. If the cerebral hemi-
412 Prof. C. S. Sherrington.
spheres bo carefully removed, e.g., from a monkey, with avoidance of
haemorrhage and of fall of body temperature, and if sufficient time
be allowed to elapse for subsidence in the animal of what may be
called immediate shock, movements can be evoked remarkably
different from those I have ever seen elicitable as purely spinal
or as cerebral reactions. If a finger of one of the monkey's
hands bo stimulated, for instance, by dipping it into a cup of
hot water, there results an extensive reflex reaction involving
movement of the whole upper limb. The wrist is extended, the
elbow flexed, the shoulder protracted, the upper arm being drawn
forward and somewhat across the chest. The movement occurs after
a variable and usually prolonged period of latent excitation. The
movement, although it may be fairly rapid, strikes the observer each
time as perfectly deliberate ; it is of curiously steady and "smooth "
performance. Sometimes it is carried out quite slowly, and then, as
a rule, the extent of it is less ample. The most striking feature of
the reflex is, however, that when the actual movement has been
accomplished the contraction of the muscles employed in it does not cease
or become superseded ly the action of another group, but is continued
even for ten and twenty minutes at a time. The new attitude assumed
by the limb is maintained, and that too without clonus or even tremor.
In the instance cited, namely, that of the fore limb, the posture
assumed suggests the taking of a forward step in quadrupedal pro-
gression, and in that posture the animal will remain for a quarter of
an hour at a time.
The degree of, for instance, flexion assumed in the new posture
seems much dependent on the intensity and duration of the stimulus
applied. If the degree is extreme, the attitude of the limb may not
be maintained to its full extent for the time mentioned ; thus, the
• elbow, at first fully flexed, will in the course of a minute or so be
found to have opened somewhat. This opening can be often seen to
• occur per saltum, as it were, but the steps are quite small, and recur-
rent at unequal intervals of between perhaps a quarter of a minute
and a minute. After some relaxation from the extreme phase of the
posture has taken place, the less pronounced attitude, e.^.,semiflexion
at the elbow, may persist without alteration obvious to inspection for
ten minutes or more. Apart from the occasional step-like relaxations,
the contraction of the muscles is so steady as to give an even line
when registered by the myograph. A renewed stimulation of the
finger excites further flexion, which is maintained as before in the
way above described. The posture can be set aside without diffi-
culty by taking hold of the limb and unbending it ; the resistance
felt in the process of so doing is slight ; the posture thus broken down
is not reassumed when the limb is then released.
Analogous results aro obtainable on the hind limb. Hot water
Cataleptoid Reflexes in the Monkey. 413
applied to a toe evokes always, so far as I have seen, flexion of ankle
and knee ; usually of hip also. This movement is " deliberately "
executed, and always institutes a maintained posture.
If finger (or toe) of both right and left limb be placed together in
the hot water, there results symmetrical reflex movement of both the
right and the left fore limbs (or hind limbs), leading to assumption
of a fairly symmetrical posture by the right and left limbs respec-
tively, the posture being similar to but duplicate of that evoked in
the one limb only on excitation of that limb. This may appear a
self-evident sequel to the observation given earlier, but is not so
when an observation immediately to be mentioned is taken into con-
sideration.
Not the least interesting part of the reflexes under consideration
is a remarkable glimpse which they allow into the scope of reflex
inhibition as regards the co-ordinate of movements of the limbs.
Although the posture taken up by the right fore limb consequent
upon excitation of a finger is symmetrically duplicated by the left
limb when both hands are simultaneously stimulated, the effect of
excitation of the two hands does not lead to symmetrical posture if
the excitation be not synchronous but successive. If when the right
arm has already assumed its posture in response to an excitation of
the right hand, the left hand be stimulated, there results, while the
left arm in obedience to the excitation is lifted and placed in the
flexed posture, an immediate and, if the stimulus be at all more than
slight, complete relaxation of the right arm. The right arm drops
flaccid while the left is raised and maintained in the raised attitude.
Similarly, excitation of the right foot breaks down the posture
assumed by the right arm, and conversely, and even more easily,
stimulation of the right hand breaks down a posture assumed by the
right leg. Again, a nip of the right pinna causes relinquishment of
a posture assumed by the righb arm or by the right leg. If the right
pinna is pinched when both arms are in this cataleptoid posture, com-
plete inhibition can be readily exerted on the right arm, but usually
only partial relinquishment can be induced in the left arm. To exert
complete inhibition upon the posture of the left arm, the pinna
pinched must be that of the left side. Similarly the posture reflexly
evoked by appropriate stimulation of either hind limb can be
inhibited by excitation of either pinna or of either fore limb, but
predominantly by pinna and fore limb of the same side as the limb
to be inhibited. The inhibition of the hind limb is much more easily
elicited from the opposite hind limb than from the opposite fore limb
or opposite ear. I have never yet seen it obtained diagonally upon the
fore limb from the opposite hind limb.
The movements obtained in the limbs by exciting the limbs them-
selves are only cited above as examples to illustrate the general
414 Prof. C. S. -Sheningtou.
characters of the condition. The details of the results will be given
in a fuller paper dealing with the subject. I was prevented from,
inquiring thoroughly into the phenomenon when it was first met
with ; but in the course of the present summer and autumn the
investigation has been systematically undertaken. I will conclude
this preliminary note by adding that throughout the observations the
animal's respiration remains apparently unaffected by the stimuli
effective to produce the various reflexes and inhibitions such as above
described. The respiration is tranquil, rather deep, regular, and
often somewhat frequent. The animal in all niy experiments has been
completely blind, but a sharp conjunctival reflex exists. The knee
jerks are elicitable but are not exaggerated. Thetonus of the sphinc-
ters appears about normal. The pulse is full, regular, and fairly
frequent.
I have not at present succeeded in evoking the cataleptoid reflex
by simply placing the limb in the desired posture.
In applying the term cataleptoid to these reflexes, I do so because
the reflexes recall, in some respects, strikingly certain phases of
hypnotic condition, by some writers distinguished as cataleptic, and
because the strict significance of the prefix implies a steady main-
tenance of possession subsequent to seizure, and is therefore peculiarly
applicable here, whether these reflexes be or be not allied to hypnotic
catalepsy.
" On Reciprocal Innervation of Antagonistic Muscles. Third
Note." By 0. S. SHERRIXGTON, M.A., M.D., F.R.S., Holt
Professor of Physiology, University College, Liverpool.
Received December 29, 1896,— Read January 21, 1897.
In a former number* of these c Proceedings ' attention was drawn
to a particular form of correlation existing between the activity of
antagonistic muscles. In it, one muscle of an antagonistic couple is,
it was shown, relaxed in accompaniment with active contraction of
its mechanical opponent. The instance then cited was afforded by
certain of the extrinsic muscles of the eyeball, but I had previously
noted indications of a like arrangement in studying the reflex actions
affecting the muscles at the ankle-joint of the frog,f and it seemed
probable that the kind of co-operative co-ordination demonstrated for
the ocular muscles might be of extended application and occurrent
in various motile regions of the body. The observations to be men-
tioned below do actually extend this kind of reciprocal innervation
* Vol. 52. April, 1893. Sherrington.
t Foster's ' Journ. of Phyeiol.,' TO!. 13, 1892.
On Reciprocal Liner vation of Antagonistic Muscles. 415
to the muscles of antagonistic position acting about certain joints of
the limbs.
If transection of the neural axis be carried out at the level of the
crura cerebri in, e.g., the cat, there usually ensues after a somewhat
variable interval of time a tonic rigidity in certain groups of skeletal
muscles, especially in those of the dorsal aspect of the neck and tail
and of the extensor surfaces of the limbs. The details of this condi-
tion, although of some interest, it is unnecessary fco describe here and
now, except in so far as the extensors of the elbow and the knee are
concerned. These latter affect the present subject. The extensors of
the elbow and the knee are generally in strong contraction, but alto-
gether without tremor and with no marked relaxations or exacerba-
tions. On taking hold of the limbs and attempting to forcibly flex
the elbow or knee a very considerable degree indeed of resistance is
experienced, the triceps brachii and quadriceps extensor cruris
become, under the stretch which the more or less effectual flexion puts
upon them, still tenser than before, and on releasing the limb the
joints spring back forthwith to their previous attitude of full exten-
sion. Despite, however, this powerful extensor rigidity, flexion of
the elbow may be at once obtained with perfect facility by simply
stimulating the toes or pad of the fore foot. When this is done the
triceps enters into relaxation and the biceps passes into contraction.
If, when the reflex is evolved, the condition of the triceps muscle is
carefully examined, its contraction is found to undergo inhibition, and
its tenseness to be broken down synchronously with and indeed very
often accurately at the very moment of onset of reflex contraction in
the opponent prebrachial muscles. The guidance of the flexion
movement of the forearm may therefore be likened to that used in
driving a pair of horses under harness. The reaction can be initiated
in more ways than one, electrical excitation of a digital nerve or
mechanical excitation of the sensory root of any of the upper cervical
nerves may be employed ; I have seen on one occasion a rubbing of
the skin of the cheek of the same side effective.
Similarly in the case of the hind limb. The extensor muscles of
the knee exhibit strong steady Don-tremulent contraction under the
appropriate conditions of experiment. Passive flexion of the knee
can only be performed with use of very considerable force, the quad-
riceps becoming tight as a stretched string. The application of hot
water to the hind foot then elicits, nevertheless, an immediate flexion
at knee and hip, during which not only are the flexors of those joints
thrown into contraction, but the extensors of the knee joint are
simultaneously relaxed. Electric excitation of a digital nerve or of
the internal saphenous nerve anywhere along its course will also
initiate the reflex.
The same relaxation of existing contraction in the extensors can
416 On Reciprocal Innervation of Antagonistic Muscles.
be obtained by electrical excitation of the tract in the crura cerel-ri,
when, as sometimes happens, that excitation evokes flexion at elbow
or at knee. This and the previous fact which evidences that the
result is obtainable after complete removal of the whole cerebrum
bear out the view arrived at in my former paper that for this
reciprocal and, as I believe, elementary co-ordination, it is not essen-
tial that " high level " centres (Hughlings Jackson) be employed.
I incline to think, however, that this kind of co-ordination at elbow
and knee is probably largely made use of in movements initiated via
the cerebral hemispheres as well as in the lower reflexes, on the
observation of which the present Note is based. This conclusion is
indicated by its occurring in response to excitation of the pyramidal
fibres in the crura. In the case of the reciprocal in nervation of
antagonistic ocular muscles I was able to prove that it took place
even in " willed movements." It seems, in view of what has been
shown above, legitimate to extend that result to the additional examples
afforded by elbow-joint and knee.
Regarding the innervation of the triceps brachii and quadriceps
extensor cruris, it is interesting to note that these muscles, which are
of all among the limb muscles particularly difficult to provoke to
action by local spinal reflexes, are the very ones which, when the level
of the transection is pontial or prepontial, exhibit tonic contraction the
most markedly. The well-known and oft-corroborated Sanders-Ezn
phenomenon of inaccessibility of the extensors of the knee to spinal
reflex action has, as I have recently shown, certain limitations, but
at the same time so long as the transection is spinal — even when
carried out so as to isolate not merely a portion of, but the whole,
spinal cord entire from bulb to filurn terminale — does apply very
strictly to excitations arising in its own local region proper. And
the spinal reflex relations of the triceps brachii in this respect, as
pointed out elsewhere, somewhat resemble those of the distal portion
of the quadriceps extensor of the leg. Alteration of the site of tran-
section from infrabulbar to suprabulbar levels works a curious change
in this. The Sanders-Ezn phenomenon then becomes subject to strik-
ing contravention. I have, after the higher transection, several times
seen excitation of the hind foot itself provoke unilateral ideolateral
extension of knee, a result incompatible with the Sanders-Ezn rule
even under the limitations of ideolaterality, &c., which I consider
must be attached to it. And similarly with the triceps at the elbow.
The difference between the accessibility of the quadriceps to reflex
action after infrabulbar and after suprabulbar transection may, how-
ever, be less abrupt than it appears at first sight, and a superficial
rather than a fundamental distinction. When extensor rigidity has
ensued at elbow and knee after suprabulbar transection, the reflex
excitability of triceps brachii and quadriceps cruris seems in a man-
On Cheirostrobus, a new Type of Fossil Cone. 417
ner as difficult as in the presence of exclusively spinal mechanisms.
The reflex inhibitions the subject of this Note show, however, that the
accessibility is not really greatly or even at all altered ; the nexus is
maintained, but the conduction across it is signalised by a different
sign, minus instead of plus. The former, to find expression, must
predicate an already existent quantity of contraction — tonus, to take
effect upon. It seems likely enough that even when the transection is
infrabulbar and merely spinal mechanisms remain in force, the same
nexus obtains, but that then that background of tonic contraction
is lacking, and that lacking the play of inhibitions remains invisible,
never coming within the field of any ordinary method of observation.
Under the conditions adopted in my experiments, various other
reflex actions, that seem probably examples of this same kind of co-
ordination, can be studied, for instance, a sudden depression arid
curving downward of the stiffly elevated and tonically up-curved tail
which can be elicited by a touch upon the perineum. But with these
and also with other details regarding the reflexes at elbow and knee
T hope to deal more fully in a paper to which the experiments re-
corded here are contributory.
" On Cheirostrobus, a new Type of Fossil Cone from the Calci-
ferous Sandstone." By D. H. SCOTT, M.A., Ph.D., F.R.S.,
Hon. Keeper of the Jodrell Laboratory, Royal Gardens,
Kew. Received December 29, 1896 — Read January 21,
1897.
The Peduncle.
The first indication of the existence of the remarkable type of
fructification about to be described, was afforded by the study of a
specimen in the Williamson collection, from the well-known fossili-
ferous deposit at Pettycur, near Burntisland, belonging to the Calci-
ferous Sandstone Series at the base of the Carboniferous formation.
This specimen is a fragment of stem, of which seven sections are pre-
served in the collection.* Its discoverer thought it might possibly
belong to the Lepidostrobus found in the same bed. " If so," he ad.ds,
" it has been part of the axis of a somewhat larger strobilus than
those described." f
A detailed examination of the structure of this specimen convinced
me that it is essentially different from any Lepidodendroid axis, and
is, certainly, anew type of stem.J
* The cabinet-numbers are 539 — 545.
t Williamson, " Organisation of the Fossil Plants of the Coal-measures." Part
III. ' Phil. Trans.,' 1872, p. 297.
J A short account of this specimen was given by me before the Botanical Section
of the British Association at the Liverpool meeting, 1896.
418 Dr. D. H. Scott. On Cheirostrobus, a new Type
As it was the examination of this fragment of stem which first },ut
me on to the track of the new cone, it may be well shortly to describe
its chief characteristics, reserving all details for a future paper.
The specimen, which is about 7 mm. in diameter, bears the bases
only of somewhat crowded leaves, the arrangement of which, though
not quite clear, was most probably verticillate, with from nine to
twelve leaves in a whorl, those of successive whorls being superposed.
Each leaf-base consists of a superior and an inferior lobe, and each
lobe is palmately subdivided into two or three segments.
The leaf-traces, which are single bundles where they leave the
central cylinder, subdivide in both planes on their way through the
cortex, to supply the lobes and segments of the leaf.
The central cylinder is polyarch, the strand of wood having from
nine to twelve prominent angles, with phloem occupying the furrows
between them. With the exception of the spiral protoxylem-elements
at the angles, the tracheae have multiseriate bordered pits, thus differ-
ing conspicuously from the scalariform tracheae of the Lepidodendrere.
The interior of the stele is occupied by tracheas intermingled with
conjunctive parenchyma. There is a well-marked formation of
secondary tissues by means of a normal cambium.*
The Strolilus.
Mr. B. Kidston, F.Gr.S., kindly informed me that he had in his
possession sections of a fossil cone from Burntisland having certain
points in common with the Williamson specimen. On inspecting
these sections with Mr. Kidston I was soon convinced that this uude-
scribed cone really belonged to the same plant as the fragment of stem
in the Williamson collection, and that the latter might well be the
peduncle of the former. At the same time, I satisfied myself, and
Mr. Kidston agreed with me, that the whole organisation of his cone
is fundamentally different from that of any Lepidostrobus, the deci-
sive point being that the new cone has compound branched sporo-
* The general structure of this axis, including the course of the bundles and the
subdivision of the bracts, is correctly described by Williamson, loc. cit., p. 297. -As
regards the latter point, he says " peripherally the bark breaks up into main or
primary bracts, which again subdivide, as in the transverse section, into secondary
ones, demonstrating that each primary bract does not merely dichotomize, but sub-
divides, both horizontally and vertically, into a cluster of bracts — a condition corre-
sponding with what T have already observed in the smaller strobili described."
These smaller strobili are those of the Burntisland Lepidostrobus, to which, by a
strange coincidence, Williamson, loc. cit., p. 295, erroneously attributed the same
character, as regards subdivision of the bracts, which actually exists in the new cone.
The only explanation appears to be, that Williamson interpreted the strucbure of
the Lepidoatrobus in the light of that of the peduncle, which, as we shall see, really
belonged to a totally different fructification.
of Fossil Cone from the Calciferous Sandstone. 4J9
phylls, eauli of which bears a number of sporangia. Ifc became
evident that this cone must be placed in a new genus, and the con-
clusion arrived at from the study of the peduncle was thus confirmed.
Mr. Kidston most generously handed over his sections to me for
examination and description, and also obtained for me from the
owner the remains of the original block, from which I have had a
number of additional sections prepared.
Only a single specimen of the cone is at present known. Before
cutting sections, the piece, which includes the base but not the apex
of the sfcrobilus, was about 2 inches long. It was found at Pettycur,
near Burntisland, in 1883, by Mr, James Benuie of Edinburgh. The
specimen is calcified, and its preservation is remarkably perfect, so
that the whole structure is well shown, though the complexity of its
organisation renders the interpretation in some respects difficult.
The cone in its present somewhat flattened condition measures
about 5 cm. by 2'3 cm. in diameter. The diameter in its natural state
would have been at least 3'5 cm. That of the axis is about 7 mm.,
exactly the same as that of Williamson's peduncle. Thus the extreme
length of the sporophylls, which have on the whole an approxi-
mately horizontal course, is about l-4 cm.
The sporophylls are arranged in somewhat crowded verticils,
fourteen of which were counted in a length of an inch, 2'5 cm. There
are twelve leaves in each whorl, and the members of successive
whorls are accurately superposed, a fact which is shown with the
greatest clearness in tangential sections of the cone. This is evi-
dently a point of great significance in considering the affinities of the
fossil.
The sporophylls themselves have a remarkably complex form. Each
sporophyll at its insertion on the axis, consists of a short basal
portion or phyllopodium ; the bases of the sporophylls belonging to
the same verticil are coherent. The sporophyll branches immediately
above its base, dividing into a superior and an inferior lobe, which lie
directly one above the other in the same radial plane. Almost at the
same point, each of the lobes subdivides in a palmate manner into
three segments, which assume a horizontal course, whereas the com-
mon phyllopodium has an upward inclination. It is probable that
sometimes, especially at the base of the cone, there may be two
instead of three segments to each lobe. As a rule, however, each
sporophyll consists of six segments, of which three belong to the
superior (ventral or posterior) and three to the inferior (dorsal or
anterior) lobe.
The segments are of two kinds — sterile and fertile. Both alike
consist of a long, straight, slender pedicel, running out horizontally,
and terminating at the distal end in a thick laminar expansion. The
sterile segments are the longer, and in each the lamina bears an
420 Dr. D. H. Scott. On Oheirostrobus, a new Type
upturned foliaceous scale as well as a shorter and stouter downward
prolongation.
Each of the fertile segments ends in a fleshy laminar enlargement
not unlike the peltate scale of an Equisetum or a Galamostachys.
These fertile laminae, which are protected on the exterior by the
overlapping ends of the sterile segments, bear the sporangia. Four,
perhaps in some cases five, sporangia are attached, by their ends
remote from the axis, to the inner surface of the peltate fertile lamina.
Each sporangium is connected with the lamina by a somewhat narrow
neck of tissue into which a vascular bundle enters. The sporangia
are of great length, and extend back along the pedicels until they
nearly or quite reach the axis.
The sterile and fertile segments alternate regularly, one above the
other, in the same vertical series. So much is evident, but the ques-
tion which segments are fertile and which sterile, has presented great
difficulties, owing to the fact that the same segment can scarcely ever
be traced continuously throughout the whole of its long course, and
that the pedicels of sterile and fertile segments present no constant
distinctive characters. For reasons, however, which will be fully
given in a subsequent paper, I think it highly probable that in each
sporophyll the segments of the lower lobe are sterile, and those of
the upper lobe fertile, constituting the sporangiophores.
The sporangia and pedicels are all packed closely together so as to
form a continuous mass. The external surface of the cone was com-
pletely protected by its double investiture of fertile and sterile
laminae.
The spores are well preserved in various parts of the cone, and, so
far as this specimen shows, are all of one kind, their average dia-
meter being 0'065 mm. At the base of the cone, where macrospores,
if they existed, might naturally be looked for, the spores are of the
same size as elsawhere. So far, then, there is no evidence of hetero-
spory. The spores are considerably larger than the microspores
of the Lepidostrobi. Those of the Burntislaud Lepidostrobus, for
example, are barely 0*02 mm. in diameter. The spores of our plant
approach in size those of Sphenophyllum Dawsoni, or the microspores
of C 'alamo stacliys Gaslieana.
The sporangial wall, as preserved, is only one cell in thickness ; it
bears no resemblance to the palisade-like layer which forms the wall
of the sporangium in Lepidostrobus, but has the same structure as
that of a C alamo stachys* The sporangial wall of Sphenophyllum
Dawsoni is similar.
The anatomy of the axis of the cone agrees closely with that of
* See Weiss, " Steinkohleu-Calamarien," yol. 2, 1884, Plate XXIV, figs. 3, 4,
and 5 ; Williamson and Scott, " Further Observations on the Organisation of the
Fossil Plants of the Coal-measures," Part I, ' Phil. Trans./ 1894, PL 81, fig. 31.
of Fossil Cone from the Calciferous Sandstone. 421
the peduncle above described, except for the absence of any secondary
tissues. The wood has twelve prominent angles, at which the spiral
tracheae are situated, so its development was, no doubt, centripetal.
The inner tracheae have pitted walls, and are intermixed with scat-
tered parenchymatous cells, imperfectly preserved. The phloem has
entirely perished.
The most interesting anatomical feature is the course of the leaf-
trace bundles, which can be followed with the greatest exactness on
comparing sections in the three directions.
A single vascular bundle starts from each angle of the stele for
each sporophyll, and passes obliquely upwards. When less than
half way through the cortex, the trace divides into three bundles,
one median and two lateral. The lateral strands are not always both
given off exactly at the same point. A little farther out, the median
bundle divides into two, which in this case lie in the same radial
plane, so that one is anterior, and the other posterior. The median
posterior bundle is the larger, and before leaving the cortex this, in
its turn, divides into three. There are now six branches of the
original leaf-trace, three anterior, and three posterior, which respec-
tively supply the lower and upper lobes of the sporophyll. The three
segments of the lower lobe are supplied by the two lateral bundles
first given off, and by the anterior median bundle, while the upper
segments receive the posterior median bundle and its two lateral
branches. In the base of the sporophyll, all six bundles can be
clearly seen, in tangential sections of the cone, three above and three
below. As the segments become free, one bundle passes into each,
and runs right through the pedicel to the lamina. In the fertile
lamina the bundle subdivides, a branch diverging to the point of
insertion of each sporangium.
One of the longitudinal sections passes through the base of the
cone, so as to show part of the peduncle in connection with it. In
this peduncle secondary wood is present, just as in the separate
specimen belonging to the Williamson collection. Higher up in
the axis of the cone, where the sporophylls begin to appear, the
secondary wood dies out. This evidence materially confirms the
conclusion that the Williamson peduncle really belongs to our
strobilus.
Diagnosis.
It is evidently necessary to establish a new genus for the reception
of this fossil; the generic name which I propose is Cheircstrobus,
intended to suggest the palmate division of the sporophyll-lobes
(xeipi hand). The species maybe appropriately named Pettycurensis,
from the locality where the important deposit occurs, which has
yielded this strobilus and so many other valuable specimens of
422 Dr. D. H. Scott. On Cheirostrobus, a new Type
palaeozoic vegetation. The diagnosis may provisionally ruu as
follows : —
Cheirostrobus, gen nov.
Cone consisting 9f a cylindrical axis, bearing numerous compound
sporophylls, arranged in crowded many-membered verticils.
Sporophylls of successive verticils superposed.
Each sporophyll divided, nearly to its base, into an inferior and a
superior lobe; lobes palmately subdivided into long segments, of
which some (probably the inferior) are sterile, and others (probably
the superior) fertile, each segment consisting of an elongated stalk
bearing a terminal lamina.
Lammas of sterile segments foliaceous ; those of fertile segments
(or sporangiophores) peltate.
Sporangia large, attached by their ends remote from the axis, to
the peltate laminae of the sporangiophores.
Sporangia on each sporangiophore, usually four.
Spores very numerous in each sporangium.
Wood of axis polyarch.
C. Pettycurensis, sp. nov.
Cone, 3—4 cm. in diameter, seated on a distinct peduncle. Sporo-
phylls, twelve in each verticil.
Each sporophyll usually sexpartite, three segments belonging to
the inferior, and three to the superior, lobe.
Sporangia densely crowded.
Spores about 0'065 ram. in diameter.
Horizon: Calciferous Sandstone Series.
Locality : Pettycur, near Burntisland, Scotland. Found by Mr.
James Bennie, of Edinburgh.
Both generic and specific characters are manifestly subject to alter-
ation, if other similar fossils should be discovered. In the mean time
the above diagnoses are given, in order to facilitate identification.
Affinities.
Any full discussion of affinities must be reserved for the detailed
memoir, which I hope to lay before the Royal Society in a short time.
At present only a few suggestions will be offered
The idea of a near relationship to Lepidostrobus — so specious at
firsb sight — is negatived by ascurate investigation. There may have
been a certain resemblance in external habit, as there is in the
naked-eye appearance of the sections, but this means nothing more
than that the specimen is a large cone, with crowded sporophylls
and radially elongated sporangia. The only real resemblance to
Lepidostrobus is in the polyarch strand of primary wood, but even
here the details, as, for example, the structure of the trachea?, do not
of Fossil Cone from the Calciferous Sandstone. 423
agree. In other respects the differences from any Lepidodendroid
fructification are as great as they can be.
I do not doubt that the genus with which Cheirostrobus has most
in common is Sphenophyllum. The chief points of agreement are as
follows.
1. The superposed foliar whorls. This certainly agrees with the
vegetative parts of Sphenophyllum, and, according to Count Solms-
Laubach, the superposition holds good for the bracts of the strobili
also.*
2. The deeply divided palmatifid sporophylls agreeing with the
leaves of various species of Sphenophyllum, e.g., 8. tenerrimum.
3. The division of the sporophyll into a superior or ventral, and
an inferior or dorsal, lobe, agreeing with the arrangement in
'Sphewophyllum Dawsoni, or 8. cuneifolium, according to M. Zeiller's
interpretation.f
4. The differentiation of the sporophyll into sterile segments
(bracts) and fertile segments (sporangiophores). The comparison
with Sphenophyllum is much strengthened if, as I believe to be the
43ase, the segments of the inferior lobe in Cheirostrobus are sterile,
and those of the superior lobe fertile.
5. The repeated subdivision of the leaf-trace vascular bundles, in
passing through the cortex of the axis,J as in Sphenophylhim
Stephanense.
6. The attachment of the sporangia to a laminar expansion at the
•distal end of the sporangiophore. As regards this point, comparison
should be made with the Bowmanites Romeri of Count Solms-Lau-
bach (loc. cit.).
7. The structure of the sporangial wall.
I think that the sum of these characters, to which others might be
added, justifies the suggestion that Cheirostrobus may be provisionally
placed in the same phylum, or main division, of Pteridophyta, with
Sphenophyllum, though indications of possible affinities in other
directions are not wanting, and will be discussed on another occa-
sion.
Cheirostrobus, even more than Sphenophyllum itself, appears to
•combine Calamarian with Lycopodiaceous characters, and might
reasonably be regarded as a highly specialised representative of an
•ancient group of plants which lay at the common base of these two
series.
It appears likely that in Cheirostrobus one of those additional forms
* ' Bowmanites Romeri, eine neue Sphenophylleen Fructification,' 1895, p. 242.
t " Etude sur la constitution de 1'appareil fructificative des Sphenophyllum."
•* Mem. de la Soc. Q-eol. de France, Paleontologie,' Mem. 11, 1893, p. 37.
J Cf. Renault, ' Cours de Botanique fossile,' vol. 2, PL 14, fig. 2 ; PL 15, fig. 3,
Tol. 4, p. 15.
VOL. LX. 2 K
424 Proceedings and List of Papers read.
of Palaeozoic Cryptogams, allowing of comparison with SphenopTiyllum,
lias actually been brought to light, the discovery of which Dr.
Williamson and I ventured to anticipate at the close of our first joint
memoir.*
January 28, 1897,
Sir JOSEPH LISTER, Bart., RR.C.S., D.C.L., President, followed
by Sir JOHN EVAN'S, K.C.B., Treasurer and Yice- President, in
the Chair.
Mr. John Eliot and Dr. Edward Charles Stirling were admitted
into the Society.
A List of the Presents received was laid on the table, and thanks
ordered for them.
The Treasurer offered the congratulations of the Society to the
President on his elevation to the peerage.
The following Papers were read :—
I. " On the Capacity and Residual Charge of Dielectrics as affected
by Temperature and Time." By J. HOPKINSON, F.R.S., and
E. WILSON.
II. " On the Electrical Resistivity of Eleptrolytic Bismuth at Low
Temperatures and in Magnetic Fields." By JAMES DEWAR,,
M.A., LL.D., F.R.S., Fullerian Professor of Chemistry in the
Royal Institution; and J. A. FLEMING, M.A., D.Sc., F.R.S.,
Professor of Electrical Engineering in University College,
London.
III. " On the Selective Conductivity exhibited by certain Polarising
Substances." By JAGADIS CHUNDER BOSE, M.A., D.Sc., Pro-
fessor of Physical Science, Presidency College, Calcutta.
Communicated by Lord RAYLEIGH, F.R.S.
- * Williamson and Scott, " Further Observations on the Organisation of the
Fossil Plants of the Coal-measures," Part I, ' Phil. Trans./ B, 1894, p. 946.
On the Capacity and Residual Charge of Dielectrics. 425
"On the Capacity and Residual Charge of Dielectrics as
affected by Temperature and Time." By J. HoPKlNSOk;
F.R.S., and E. WILSON. Received December 15, 1896,—
Read January 28, 1897.
(Abstract.)
The major portion of the experiments described in the paper
have been made on window glass and ice. It is shown that for long
times residual charge diminishes with rise of temperature in the
case of glass, but for short times it increases both for glass and ice.
The capacity of glass when measured for ordinary durations of time,
such. as l/100th to l/10th second, increases much with rise of tem-
perature, but when measured for short periods, such as 1/106 second,
, it does not sensibly increase. The difference is shown to be due to
the residual charge, which comes out between l/50,000th second and
l/100fch second. The capacity of ice when measured for periods of
l/100th to l/10th second increases both with rise of temperature,
and with increase of time, its value is of the order of 80, but when
measured for periods such as 1/106 second, its value is less than 3.
, The difference again is due to residual charge coming out during
short times. In the case of glass, conductivity has been observed at
fairly high temperatures and after short times of electrification ; it is
found that the conductivity after l/50,000th second electrification is
much greater than after l/10,000th, but for longer times is sensibly
constant. Thus a continuity is shown between the conduction in
dielectrics which exhibit residual charge and deviation from Max-
well's law and ordinary electrolytes.
'•' On the Electrical Resistivity of Electrolytic Bismuth at Low
Temperatures, and in Magnetic Fields." By JAMES DEWAR,
M.A., LL.D., F.R.S., Fullerian Professor of Chemistry in
the Royal Institution; and J. A. FLEMING, M.A., D.Sc,.
F.R.S., Professor of Electrical Engineering in University
College, London. Received January 4, — Read January 28,
1897.
In a previous communication to the Royal Society we have pointed
out the behaviour of electrolytically prepared bismuth when cooled to
very low temperatures, and at the same time subjected to transverse
magnetisation.* During the last summer we have extended these
* See ' Proc. Roy. Soc.,' vol. 60, p. 72, 1896. " On the Electrical Resistivity of
Bismuth at the Temperature of Liquid Air," by James Dewar and J. A. Fleming.
See also ' Phil. Mag.,' September, 1895, Dewar and Fleming " On the Variation in
the Electrical Resistance of Bismuth when cooled to the Temperature of Solid Air."
2 K 2
426 Profs. J. Dewar and J. A. Fleming. On ike
observations, and completed them, as far as possible, by making-
measurements of the electrical resistance of a wire of pure bismuth,
placed transversely to the direction of the field of an electromagnet,
and at the same time subjected to the low temperature obtained by
the use of liquid air.
Sir David Salomons was so kind as to lend us for some time his
large electromagnet, which, in addition to giving a powerful field, is
provided with the means of easily altering the interpolar distance of
the pole pieces, and also for changing from one form of pole piece to
another.
The form of the pole piece most frequently used was that of a
truncated cone. The magnet was always excited by a constant
current obtained from a constant potential circuit. To save the
considerable labour of determining again and again the strength of
the interpolar field, this was determined once for all, corresponding
to various interpolar distances and a given exciting current. The
field was measured by suddenly removing from it a small exploring
coil of wire of known area, the same being connected to a standardised
ballistic galvanometer.
By this means a curve was constructed which showed at once the
axial interpolar field at the central point in terms of the interpolar
distances, the magnetising current being kept constant. This curve
proved, as was to be expected, to be nearly a rectangular hyperbola.
This being done the bismuth wire to be examined was formed into
a narrow loop of a single turn, about 3 or 4 cm. in length, and the
ends soldered to leading-in wires of copper. The loop was placed in
a small glass vacuum vessel, with the plane of the loop perpendicular
to the direction of the axial magnetic field of the magnet. The loop
was placed at equal distances from the two pole pieces, and in a
nearly uniform field of known strength.
The vacuum vessel was then filled up with either liquid air, a
solution of solid carbonic acid in ether, or else simply with paraffin
oil. In a fourth case the vacuum vessel was closed, and liquid air
having been placed in it, this liquid was caused to boil under a
reduced pressure of 25 mm., thus giving a temperature falling as low
as —203° C. In another experiment the vacuum vessel was dispensed
with, the bismuth wire was simply wrapped in cotton wool, placed
between two pieces of thin mica between the pole pieces, and by
pouring upon the wrapping a copious libation of liquid air, the
temperature of the bismuth wire was reduced to —185° C.
In all cases great care was taken to avoid thermo-electric complica-
tions, by providing that the soldered junctions by which the bismuth
wire is connected to the copper leading-in wire were at exactly the
'same temperature, and to secure this the junctions were always kept
well covered with the refrigerating solution.
Electrical Resistivity of Electrolytic Bismuth. 427
The bismuth employed was electrolytic bismuth pressed into wire
0*5245 mm. in diameter, and its purity was confirmed by spectro-
scopic examination.
These arrangements being made, the observations consisted in
measuring the electrical resistance of the bismuth at one tempera-
ture, but when the transverse magnetic field had values varying from
zero to nearly 22,000 C.G.S. units.
In the following tables the results are collected. The electrical
resistivity of the bismuth is stated for each temperature, and for the
various transverse fields employed.
As the specimens of the bismuth wire used in the various experi-
ments had different lengths, the actual figures of observation are not
given, but they have been reduced so as to give the volume resistivity
of the bismuth, corresponding to a certain temperature and magnetic
field strength.
In the case of the experiment in liquid air boiling under a reduced
pressure, on account of the size of the vacuum vessel necessary to
contain the required initial volume of liquid air, the pole pieces of
the magnets could not be brought very near together, and hence the
field could not be raised to a very high value.
Hartman and Brauns Pure Electrolytic Bismuth.
Resistivity of Bismuth Transversely Magnetised at Ordinary Tem-
peratures ( + 19°C.).
Strength of field Yolume resistivity in
(C.a.S. units). C.GLS. units.
0 116,200
1,375 118,200
2,750 123,000
8,800 149,200
14,150 186,200
21,800 257,000
Resistivity of Bismuth Transversely Magnetised at —79° C.
Strength of field Yolume resistivity in
(C.G.S. units). C.G-.S. units.
0 78,300
650 83,300
2,300 103,500
3,350 114,800
4,100 134,000
5,500 158,000
7,900 201,000
14,200 284,000
428
Profs. J. Dewar and J. A. Fleming. On the
Resistivity of Bismuth Transversely Magnetised at —185° C.
Strength of field
(C.G.S. units).
0
1,375
2,750
8,800
14,150
21.800
Yolunie resistiyity in
C.GKS. units.
41,000
103,300
191,500
738,000
1,730,000
6,190,000
Hartman and Braun's Pure Electrolytic Bismuth.
Resistivity of Bismuth Transversely Magnetised at —203° C.
Strength of field
(C.G-.S. units).
0
2,450
Volume resistivity in
C.G-.S. units.
34,300
283,500
Electrical Resistivity of Bismuth in C.G.S. units, transversely
magnetised in a Constant Magnetic Field, but at variable Tem-
peratures.
Temperature
In the magnetic field.
nf thp
Oiif nf tli A
bismuth
wire.
magnetic field.
Strength 2450
C.G.S. units.
Strength 5500
C.G.S. units.
Strength 14,200
C.G.S. units.
-i- 19° C.
116,200
123,500
132,000
187,000
- 79,,
78,300
105,000
158,000
284,000
-185 „
41,000
186,000
419,000
1,740,000
-203 „
34,300
283,500
~
~~
It will be seen that the observations lead to the following conclu-
sions. If the transverse field is zero, then cooling the bismuth always
reduces its resistance. If then the bismuth is transversely magnetised,
the resistance is increased, and for every temperature below the
normal one (about 20° C.), there is some particular strength of trans-
verse field, which just annuls the effect of the cooling, and brings the
resistance of the bismuth back again to the same value it had when
not cooled, and not in any magnetic field. Hence the curves showing
the resistance at any temperature lower than the normal one (20° C.)
as a function of the transverse field, cross the curve showing the
resistance as a function of the field when taken at the normal tem-
perature. These crossing points are, however, not identical for
Electrical Resistivity of Electrolytic Bismuth. 429
different resistance-temperature-field curves. The lower the tem-
perature the less is the strength of field which will bring the bismuth
back to its original resistance when not cooled and not in the field.
The observations have been set out graphically in the diagrams in
fig8- 1> 2, and 3, and it will be seen that there are in fig. 1 four curves.
Each of these curves corresponds to a different temperature, viz., that
of liquid air (-185° C.), liquefying carbonic acid in ether (—79° C.),
ordinary temperatures (20° C.), and a fourth shorter curve, which
corresponds to a very low temperature of —203° C., obtained by
. 1.
$000,000
5,000000
4000000
I
-§ 3,000,000-
/,ooo,ooo-
Ch&nge of
of
when
O- » 3,000- /QOOO- /5,OOO- £O,000
-n 3trehg£h of Transverse Magnetic F/e/d /n C.G.S.u/7/te.
evaporating liquid air under a reduced pressure. This last curve is
only continued for a short distance. These curves show the mode of
variation of the resistance of the bismuth at a constant temperature
as a function of the transverse magnetic field ; and they show how
430 Profs. J. Dewar and J. A. Fleming. On tho
FIG. 2.
600,000 •
700,000 •
600,000 •
Cnange of Rests £/wty of
E/ec£ro/y£/'c Bismuth when transverse/y
magnetised.
(£n/arged sda/e).
O- 2OOO- 4000- 6,OOO •_ 8,OOO- ^
Strength of Transverse Magnet/'c f/'e/d m C.G.S. unite.
remarkably the resistance is affected by such magnetisation. The*
curve of resistance taken in liquid air, shows that by a transverse
magnetising field having a strength of 22,000 C.G.S. units, the
resistance of the bismuth is made 150 times greater than the resist-
ance of the same wire in a zero field, but at the same temperature.
The lower the temperature to which the bismuth is reduced the
greater is the multiplying power of a given transverse field upon its
electrical resistivity.
Hence a still lower temperature than we have been able to apply
would doubtless render the bismuth still more sensitive to transverse
magnetisation.
We have already shown that pure bismuth is no exception to the-
generally observed fact that all pure metals continuously lose their
electrical resistivity as they approach in temperature the absolute?
Electrical Resistivity of Electrolytic Bismuth. 431
zero. Hence at this last temperature it should be converted into a
non-conductor by a sufficiently strong transverse magnetisation.
This result will have to be taken into consideration in framing any
theory of electrical conduction.
In this respect bismuth is a remarkable exception to other metals^
We have tried the effect of transverse magnetisation at low tem-
peratures on zinc, iron, and nickel, but find no effect sensibly
greater at low than at ordinary temperatures, although these metals-
have their resistance affected by magnetisation to a small degree.
Bismuth has an exceptional position amongst other metals, both
in respect of its large coefficient of the Hall effect, and also in
the degree to which its resistance is thus affected by transverse
magnetisation, and in addition, as above shown, in the degree to*
which cooling to low temperatures affects this ability to be so changed
by magnetisation.
Very small amounts of impurity in the metal reduce these remark*
able qualities considerably.
We may mention here that we have repeated the experiments we
made some time ago* on certain specimens of chemically prepared
bismuth, and for which we found the electrical resistance had a
minimum value for a certain temperature. We have again verified
this fact, both for the same and for a similar specimen. In the former
experiments the bismuth wire used was embedded in paraffin wax
during the cooling, and the suspicion had arisen that strains
might thus have been produced which had affected the results.
In the repetition of the experiments, we suspended the bismuth
wire freely in liquid air, so that no strains could be produced ;.
and, in addition, we tried the effect of mechanical stress on the
resistance directly. We satisfied ourselves that the cause of the
anomaly in the behaviour of the chemically prepared bismuth in
respect of electrical resistance at low temperatures was not to be
found in any effect due to strain.
In fig. 3 a series of curves have been drawn showing the variation
in resistivity of the electrolytic bismuth for certain constant trans-
verse magnetic fields and varying temperatures. These curves were
obtained by taking sections of the curves in figs. 1 and 2. The
curves in fig. 3 are practically the continuation from 19° C. down to
— 186° C. of curves which have been given by Mr. J. B. Heiiderson,f
for a range of temperature lying above 0° C.
They show that if a wire of electrolytic bismuth is placed trans-
versely in a certain magnetic field, there is, for a wide range of field,
* See ' Phil. Mag.,' September, 1895, p. 303. Dewar and Fleming " On the
Variation in the Electrical [Resistance of Bismuth when cooled to the Temperature
of Solid Air."
t See ' Phil. Mag.,' 1894, vol. 38, p. 488.
432 On the Electrical Resistivity of Electrolytic Bismuth.
Fia. 3.
n \r
600,000-
300,000-
400,OOO-
.-^ 300,000-
«S
| £00,000-
^
JO O,000- «-
f Resist iw
of Elect ro/y
transfers
— £00
- /50° -/00° — 50°- —0° +£0°
Temperature //? decrees centigrade.
a certain temperature at which the bismuth has a minimum electrical
resistivity, and, therefore, a zero temperature coefficient, and that
the temperature of this turning point is higher the stronger the
transverse field. These curves also show that at a temperature of
about 150° C., the bismuth would probably cease to have its resis-
tivity affected by a transverse magnetic field.*
In conclusion, we desire to mention the assistance we have received
from Mr. J. E. Petavel in the work described above.
* Drude and Nernst (' Wied . Ann.,' vol. 42, p. 568) found that, with a transverse
field of 7000 C.GLS. units, the total percentage increase of resistance of electrolytic
bismuth was 22'0, 8'0, TO, and 0'4 per cent, respectively at temperatures of 16° C.,
100° C., 223° C., and 290° C.
On the Selective Conductivity of Polarising Substances. 433
" On the Selective Conductivity exhibited by certain Polarising
Substances." By JAGADIS CHUNDER BOSE, M.A., D.Sc.,
Professor of Physical Science, Presidency College, Calcutta.
Communicated by Lord RAYLEIGH, F.R.S. Received
January 14, — Read January 28, 1897.
In my paper " On the Polarisation of Electric Rays by Double-
refracting Crystals " (vide ' Journal of the Asiatic Society of Bengal,'
May, 1895), and in a subsequent paper " On a New Electro-Polari-
scope" (' Electrician,' 27th December, 1895), I have given accounts
of the polarising property of various substances. Amongst the most
efficient polarisers may be mentioned nemalite and chrysotile. Nemalite
is a fibrous variety of brucite. In its chemical composition it is a
hydrate of magnesia, with a small quantity of protoxide of iron and
carbonic acid. This substance is found to absorb very strongly
electric vibrations parallel to its length, and transmit those that are
perpendicular to the length. I shall distinguish the two directions
as the directions of absorption and transmission. Chrysotile is a
fibrous variety of serpentine. In chemical composition it is a hydrous
silicate of magnesia. Like nemalite, it also exhibits selective absorp-
tion, though not to the same extent. The transmitted vibrations are
perpendicular, and those absorbed parallel to the length. Different
varieties of these substances exhibit the above property to a greater
or less extent. I have recently obtained a specimen of chrysotile with
a thickness of only 2'5 cm. ; this piece completely polarises the trans-
mitted electric ray by selective absorption.
The action of these substances on the electric ray is thus similar to
that of tourmaline on light. It may be mentioned here that I found
tourmaline to be an inefficient polariser of the electric ray ; it does
transmit the ordinary and the extraordinary rays with unequal
intensities, but even a considerable thickness of it does not completely
absorb one of the two rays.
In Hertz's polarising gratings, electric vibrations are transmitted
perpendicular to the wires, the vibrations parallel to the wires being
reflected or absorbed. Such gratings would be found to exhibit
electric anisotropy, the conductivity in the direction of the wires
being very much greater than the conductivity across the wires.
The vibrations transmitted through the gratings are thus perpen-
dicular to the direction of maximum conductivity — or parallel to the
direction of greatest resistance. The vibration absorbed is parallel
to the direction of maximum conductivity.
As the nemalite and chrysotile polarised the electric ray by unequal
absorption in the two directions, I was led to investigate whether
434 Prof. J. C. Bose. On the Selective Conductivity
they, too, exhibited unequal conductivities in the two directions of
absorption and transmission.
Nemalite, unfortunately, is difficult to obtain, and the specimens I
could get here were too small to make the necessary measurements.
I have, however, in my possession two specimens which I brought
from India ; of these, one is a perfect specimen of a fair size, and I
obtained with it strong polarisation effects. The second piece is not
as good as the first, and rather small in size. I cut from this latter
piece a square of uniform thickness, the adjacent sides of the square
being parallel to the directions of transmission and absorption respec-
tively. The resistances of equal lengths in the two directions (with
the same cross section) were now measured.
The first specimen I gave to Messrs. Elliott Brothers for measure-
ment. They informed me, on the 13th of October last, that the
resistance in the direction of transmission was found to be 35,000
megohms, and that in the direction of absorption, only 14,000 meg-
ohms.
It will thus be seen that the direction of absorption is also the
direction of greatest conductivity, and the direction of transmission
is the direction of least conductivity.
My anticipations being thus verified, I proceeded to make further
measurements with other specimens. From the perfect specimen of
nemalite in my possession, I cut two square pieces, A and B. The
size of piece A is 2'56x2'56 cm., with a thickness of 1/1 cm. B is-
276 x 2-76x1-2 cm.
For the determination of resistances I used a sensitive Kelvin gal-
vanometer, having a resistance of 7000 ohms. With three Leclanche
cells, 1/4 volt each, and an interposed resistance equivalent to-
55,524 megohms, a deflection of 1 division in the scale reading was
obtained. The following table (p. 435) gives the results of the
measurements which I carried out.
The results given clearly show how the difference of absorption
in the two directions is related to the corresponding difference in
conductivity.
I then proceeded to make measurements with chrysotile. The
specimens I could obtain were not very good. I cut two from the
same piece, and a third specimen was obtained from a different
variety. The ratios of conductivities found in the three specimens
were 1 : 10, 1 : 9, and 1 : 4 respectively. In every case the direction
of absorption was found to be the direction of maximum conductivity.
[A fibrous variety of gypsum (CaS04), popularly known as Satin-
spar, also exhibits double absorption ; and in this case, too, the con-
ductivity in the direction of absorption is found to be very much
greater than in that of transmission.
exhibited by certain Polarising Substances.
435
Resistance between
Specimen A.
Deflections.
two opposed faces
2-56 x 1-1 cm.
Ratio of
the conduc-
separated by
tivities.
2 -56 cm.
In the direction of transmission
„ ,, absorption..
26
360
2136 megohms
154
| 1 :13'8
Specimen B.
Deflections.
Resistance between
two opposed faces
276 x 1-2 cm.
separated by
2-76 cm.
Ratio of
the conduc-
tivities.
In the direction of transmission
„ „ absorption . .
28
370
1983 megohms
150 „
| 1 : 13 '4
One of the strongest polarising substances I have come across is
the crystal epidote. The crystal is very small in size, and I could
not get with it complete absorption of one of the two rays. But it
exhibits very strong depolarisation effect, even with a thickness as
small as 0'7 cm. This is, undoubtedly, due to strong selective absorp-
tion in one direction. I cut a square from this crystal 0'7xO-7 cm.
with a thickness of 0'4 cm. Using an E.M.F. of 14 volts the deflections
obtained (proportional to the two conductivities) were 105 and 20
divisions respectively. The conductivities in the two directions are,
therefore, in the ratio of 5'2 : 1. With an E.M.F. of 100 volts and a
-diminished sensibility of the galvanometer, the deflections were 205
and 40, the ratio of the conductivities being as 5'1 : 1. — January 28,
1897.]
It would thus appear that substances like nemalite which polarise by
•double absorption, also exhibit double conductivity. It is probable
that, owing to this difference of conductivity in the two directions,
each thin layer unequally absorbs the incident electric vibrations ;
3,nd that by the cumulative effect of many such layers, the vibrations
which are perpendicular to the direction of maximum conductivity
are alone transmitted, the emergent beam being thus completely
polarised.
[Owing to the great difficulty in obtaining suitable specimens, I
have not been able to make a more extended series of determina-
tions. The relation found, in the cases described above, between
double absorption and double conductivity is, however, suggestive.
436 On the Selective Conductivity of Polarising Substances.
It should, however, be borne in mind that the selective absorption
exhibited by a substance depends, also, on the vibration frequency of
the incident radiation. I have drawn attention to the peculiarity of
tourmaline which does not exhibit double absorption of the electric
ray to a very great extent. The specimen I experimented with is,
however, one of a black variety of tourmaline, and not of the semi-
transparent kind generally used for optical work.
Though the experiments already described are not sufficiently nume-
rous for drawing a general conclusion as to the connection between
double absorption attended with polarisation, and double conductivity,
there is, however, a large number of experiments I have carried out
which seem to show that a double-conducting structure does, as a rule,
exhibit double absorption and consequent polarisation. Out of these
experiments I shall here mention one which may prove interesting.
Observing that an ordinary book is unequally conducting in the two
directions — parallel to and across the pages — I interposed it, with its
edge at 45°, between the crossed polariser and analyzer of an electro-
polariscope. The extinguished field of radiation was immediately
restored. I then arranged both the polariser and the analyzer vertical
and parallel, and interposed the book with its edge parallel to the
direction of electric vibration. The radiation was found completely
absorbed by the book, and there was not the slightest action on the
receiver. On holding the book with its edge at right angles to the
electric vibration, the electric ray was found copiously transmitted.
An ordinary book would thus serve as a perfect polariser of the
electric ray. The vibrations parallel to the pages are completely
absorbed, and those, at right angles transmitted in a perfectly polar-
ised condition. — January 28, 1897.]
Proceedings and List of Papers read. 437
February 4, 1897.
Sir JOSEPH LISTER, Bart., F.R.C.S., D.C.L., President, in the-
Chair.
A List of the Presents received was laid on the table, and thanks-
ordered for them.
The President stated that a paper had been received from Dr.
Arthur Willey, Balfonr Student of the University of Cambridge,
the recipient of a Government Grant, and now staying at the Loyalty
Islands, to the effect that he had discovered the ova of Nautilus.
The following Papers were read: — :r-r i..
I. " On the Condition in which Fats are absorbed from the Intes-
tine." By B. MOORE and D. P. ROCKWOOD. Communicated
by Professor E. A. SCHAFER, F.R.S.
II. " The Gaseous Constituents of certain Mineral Substances and
Natural Waters." By WILLIAM RAMSAY, F.R.S., and MORRIS
W. TRAVERS, B.Sc.
III. " Some Experiments on Helium." By MORRIS W. TRAVERSA
B.Sc. Communicated by Professor W. RAMSAY, F.R.S.
IV. " On the Gases enclosed in Crystalline Rocks and Minerals."
By W. A. TJLDEN, D.Sc., F.R.S.
V. " On Lunar Periodicities in Earthquake Frequency," By C. G.
KNOTT, D.Sc., Lecturer on Applied Mathematics, Edinburgh
University (formerly Professor of Physics, Imperial Univer-
sity, Japan). Communicated by JOHN MILNE, F.R.S,
438 Messrs. B. Moore and D. P. Rockwood. On the
** On the Condition in which Fats are absorbed from the
Intestine." By B. MOORE and D. P. ROCKWOOD. Commu-
nicated by Professor E. A. SCHAFER, F.R.S. Received
December 24, 1896,— Read February 4, 1897.
(From the Physiological Laboratory of University College, London.)
In 1858 Dr. W. Marcel* announced to this Society the discovery
that bile possesses the remarkable property of dissolving to a clear
solution large amounts of fatty acids, and mixtures of these, when
heated above their melting points, and that, on cooling, these bodies
are again thrown out as a fine precipitate or emulsion.
We have repeated these experiments, and are able to confirm the
accuracy of Marcet's observation. Thus we found that 6 c.c. of dog's
bile at 62° C. dissolved completely 1'5 grams of the mixed fatty
acidsf of beef suet, and similar solubilities were found in other
-cases.
No other observations than these have, so far as we are aware,
been made on the effect of temperature on the solubility of fatty
acids in bile ; although different writers have mentioned that fatty
acids are soluble in bile, no measurements have been made of the
extent of their solubility. AltmarinJ has recently surmised that
fats are absorbed from the intestine as fatty acids, dissolved in the
intestine by the agency of the bile, but has made no quantitative
experiments on the solubilities of the fatty acids in bile. The for-
gotten experiments of Marcet, mentioned above, led us to think that
the fatty acids might possess, at tine temperature of the body, a fair
amount of solubility in bile, and as the solubility at this temperature
is that of most physiological interest, we have made a. series of deter-
minations of the solubilities of oleic, palmitic, and stearic acids, and
of natural mixtures of these in the proportions in which they occur
in lard, beef suet, and mutton suet, in the bile of the ox, pig, and
dog.
Different methods were used in the determination of these solu-
bilities : —
1. To a measured amount of the bile under experiment, kept at a
temperature of 39° C., small weighed quantities of the fatty acid
ainder experiment were added, until no more dissolved.
2. A quantity of bile was saturated at 39° C., with excess of the
fatty acid, and filtered from the excess of undissolved acid through a
* ' Eoy. Soc. Proc.,' 1858, vol. 9, p. 306.
f Throughout this communication the expression " fatty acids " means the fatty
acids present in fats, oleic, palmitic, and stearic acids.
I 'Arch. f. Anat. u. Physiol.,' 1889, Anat-.-Abth., Suppl. Band, p. 86.
Condition in which Fats are absorbed from the Intestine. 439
hot funnel, at this temperature ; the filtrate was cooled to about 0° C.,
and the precipitate collected, dissolved in ether, recovered therefrom,
and weighed ; the weight, compared with the volume of the filtrate,
gave a measure of the solubility.
3. To a series of equal volumes (10 c.c.) of bile in test-tubes, a
rising series of weights of fatty acids was added (O05, 0*1, 0'15, 0'2,
&c., grams), and those tubes noted, in which, after the lapse of a
sufficient time at 39° C., complete solution did not take place.
The following is a summary of our results.
1. Ox bile ....
2. Pig's bile ..
Lard fatty
acids.*
Beef suet
acids.
Mutton suet
acids.
Oleic acid.
Palmitic
and
stearic acids.
2 -5—4 p. c.
4
2-5— 3 p. c.
5-6 „
1—2 -5 p. c
1—2-5 „
4-5 p. c.
Less than
0-5 p. c.
3. Dog's bile . .
6 '25
4-7 „
2
—
—
The fatty acids are not dissolved as soaps, but probably as fatty
acids, for the solution becomes strongly acid ; moreover, the material
thrown out on cooling dissolves easily in ether, and, when recovered,
saponifies at once with sodium carbonate. The solution is not
entirely due to the bile salts, for mere removal of the " bile mucin "
greatly diminishes the solvent power, although the "mucin'*
redissolved in sodium carbonate solution has no solvent power, and,
again, a solution of mixed bile saltsf stronger than bile has not
nearly so much solvent power as the bile itself. . •
Palmitic and stearic acids are very feebly soluble in bile at 39° C.,
and in mixtures are probably dissolved by the aid of the admixed
oleic acid.
Action of Filtered Intestinal Contents on Fats.
The filtered intestinal contents contain both pancreatic juice and
bile, and hence should both decompose and dissolve fats at body
temperature if these are absorbed as dissolved fatty acids; this
was experimentally found to be the case with filtered intestinal con-
tents of the dog, which in different cases possessed a very variable
* The numbers given are the minimum and maximum of a number of determina-
tions in different samples of bile.
t The solution used was a 9 per cent, solution of the bile salts of a sample of ox
bile which dissolved 2'5 per cent, of the fatty acids of beef suet ; this solution oi
bile salts only dissolved 1 per cent.
VOL. LX. 2 L
440 Messrs. B. Moore and D. P. Kockwood. On the
power, dissolving 1 to 5 per cent, of the fat of beef suet at 39° C»
The solution becomes viscid, semi-fluid, or completely solid on cooling,
arid redissolves'on warming again. With the filtered contents of the
intestine of the pig and rabbit similar results were not obtained, but
the fat became altered, being in part converted into fatty acids, and
in part giving rise to a voluminous precipitate.
Simultaneous Action of Pancreas and Bile on Fats.
Finely minced, fresh dog's pancreas (1 gram) was added to bile
(10 c.c.), and then the fat of beef suet (0*25 gram) ; the fat com-
pletely dissolved in three hours at 40° C. ; on cooling, the solution
became turbid, and finally semi-solid. In a control experiment,
pancreas alone decomposed fat into fatty acids, but did not dissolve it.
The solubilities stated above are quite sufficient to account for the
removal of all the fat of the food from the intestine as dissolved fatty
acid, since they exceed the concentrations found in the intestine of
other materials, such as sugars and albumoses, which are removed
in solution. Other experiments, however, on the reaction of the
intestine during fat absorption, lead us to think that all the fat is not
removed as dissolved fatty acids, but that these are replaced to a
variable extent (in some animals, to. a very large extent or completely)
lay dissolved soaps.
Reaction of Intestinal Contents during Fat Absorption.
We have determined the reaction of the contents of the dog's
small intestine during fat absorption, from pylorus to caecum, to
various indicators, litmus, methyl-orange, and phenolphthalein, and
cannot agree with the statement of some other experimenters, that it
is acid throughout.* In sixteen experiments on this animal we only
once found the reaction acid to litmus up to the caecum, and this was
an obviously poor experiment, in which the intestine was almost
empty. The reaction to litmus at the pylorus is neutral, faintly acid,
or faintly alkaline ; from here onwards the acidity increases, reaches
a maximum about the middle of the small intestine, and then
becomes less acid, to change to alkaline at a point situate two-thirds
to three-fourths of the way along the intestine ; from this point on
to the caecum the alkalinity increases. f The reaction to methyl-
orange and phenolphthalein explains this ; the intestine is alkaline to
methyl-orange all the way from pylorus to caecum, and equally com-
* Cash, 'Arch. f. Anat. u. Physiol.,' 1881, p. 386 ; Munk, 'Zeitsck. f. Physiol.
Chem./ vol. 9, 1885, pp. 572, 574.
t There is usually a reversion to an acid reaction in the large intestine, in "which
case the contents of the caecum are almost neutral.
Condition in which Fats are absorbed from the Intestine. 441
pletely acid to phenolphthalein, showing that the acid reaction to litmus
in the upper part is due to weak organic acids, while the alkaline reaction
in the lower is due to fixed alkali, accompanied by dissolved carbonic
acid. The alkaline reaction to methyl-orange in the upper part, where
it is acid to litmus and phenolphthalein, shows that in that part there
is an excess of bases, above that quantity necessary to combine with all
the inorganic acids, which are combined with very weak organic acids
(probably fatty acids), for methyl-orange is a stable indicator, and
does not react to such acids, while litmus, and, still more so, phenol-
phthalein, are indicators which are affected by these acids. In the
lower third or thereabouts, where the reaction is alkaline to litmus,
there cannot be any fatty acids present in solution.
Any fat absorbed as free fatty acid in solution must, therefore, be
taken up from the upper two-thirds or three-fourths of the intestine
where the reaction is acid to litmus, but even here a considerable part
is probably being absorbed in solution as soaps, as is shown by the
reaction being at the same time alkaline to methyl-orange. In the
lower part all the fat absorbed must be taken up as soaps.
During fat absorption in the white rat,* the reaction of the con-
tents of the small intestine is commonly alkaline to litmus from
pylorus to ceecum, and is never acid for a greater distance than 2 or
3 in. below the pylorus ; in this animal, therefore, nearly all the fat
must be absorbed in solution as soaps.
We have not investigated the reaction of the intestinal contents
in other animals during fat absorption, but in the rabbit, during
carbohydrate absorption, it is strongly alkaline all the way, from
pylorus to caecum, and in the pig the mixed contents during the
absorption of a mixed meal (meal and oats) had a strong alkaline
reaction. As already stated, the filtered consents in these animals do
not perfectly dissolve fat, and the portion dissolved must be in the
form of soap, because the reaction remains, alkaline to litmus after
solution. In such animals it is probable that the greater part of
the fat must be absorbed as soaps.
The main objections which have been urged, against absorption of
fats as soaps are, first, absorption in presence of an acid reaction in
the dog, in which case it was supposed impossible that soaps could
be present simultaneously in solution,f and, secondly, that the
* In this animal the intestinal contents are usually semi-solid. Care was taken
to mix them so as not to obtain the alkaline surface reaction sometimes described.
On thorough mixing an alkaline reaction was obtaine.d.
f The acid reaction is also commonly supposed to preclude the possibility of the
formation of an emulsion, and Cash ('Arch. f. Anat. u. Physiol.,' 1881, p. 386), in
experiments chiefly made to determine this point, failed to find any emulsion within
the dog's intestine. In ten out of sixteen experiments we obtained more or less
emulsion, and in fire of these, in almost the entire length, a perfect emulsion, con-
taining immense numbers of minutest fat globules, and possessing a marked acid
2 L 2
442 Prof. Ramsay and Mr. Travers. The Gaseous
amount of alkali required in the intestine for the absorption of all
the fats of a fattj meal, as soaps, is out of all proportion to the
amount actually present, being about twice the total alkalinity of the
body.* The first objection has already been discussed ; it has been
shown that the acid reaction is due to weak organic acids, and that
an alkaline reaction can be obtained by the use of a proper indicator,
due to a compound of these weak acids with bases ; in other words,
to soaps.
The second objection may be met by the supposition that the same
quantity of alkali acts cyclically as a carrier in conveying quantity
after quantity of fatty radicle, as soap, from the intestine. The
soaps are, it is known, broken up in the intestinal cells, and formed
into fats by the action of the cell ; in such a reaction alkali is set free,
and there is no obvious reason why it should not be returned to the
intestine and serve to carry a fresh portion of fatty radicle dissolved
as soap into the epithelial cells. Such an action takes place in the
acid secreting cell of the gastric gland, where sodium chloride is
taken up from the blood, split into acid and alkali, and the alkali
returned to the blood while the acid passes into the gland lumen ; it
is not, therefore, unreasonable to suppose that a similar action can
take place in the intestinal absorbing cell.
We conclude that in certain animals, such as the dog, fats are absorbed
partially as dissolved fatty acids,' and partially as dissolved soaps ; while
in other animals, such as the white rat, fats are chiefly, if not entirely^
absorbed as dissolved soaps.
" The Gaseous Constituents of certain Mineral Substances and
Natural Waters." By WILLIAM RAMSAY, F.R.S., and
MORRIS W. TRAVERS, B.Sc. Received December 30, 1896,
—Read February 4, 1897.
It is still uncertain whether helium is a single elementary gas or a
mixture of two or more gases. If a mixture, it is probable that they
should occur independently, and that the proportion of the con-
stituent gases should vary in samples from different sources. During
the past year the gases obtained from a large number of minerals and
natural waters have been examined with a view to investigate this
point, and, also, to determine whether any new gaseous element could
be discovered. In every instance the results have been negative ; no
reaction to litmus. Although fats are not absorbed in the form of an emulsion, it
is evident that the formation of an emulsion in the intestine must enormously
increase the surface exposed to the action of the intestinal fluids, and proportion-
ately increase the rate at which the fats are decomposed and dissolved.
* Munk, ' Virchow's Archiv,' vol. 95, 1884, p. 408.
Constituents of certain Mineral Substances and Waters. 443.
indication of the presence of any new element has been obtained, nor
has any abnormality been observed in the spectrum of any of the
examined.
Fm. 1.
Method of Examination of the Mineral Substance.
The mineral was ground to fine powder in an agate mortar, and
then mixed with about twice its weight of acid potassium sulphate.
This mixture was placed in a hard glass tube, which was connected
with a Topler pump, and, after exhaustion, heated to a red heat by
means of a large Bunsen burner. The gases evolved were pumped
off and collected over mercury in a tube containing a little caustic
potash solution. In some instances, however, the mineral was heated
alone ; the same result was obtained, but the evolution of gas takes
place rather more slowly. In order to diminish any chance of leak-
age of air into the apparatus, the hard glass tube was connected with
the pump in the manner shown in fig. 1. The tube was drawn
out to a neck at the point A. A piece of thick- walled rubber tube
was fitted over the end of the tube B connected with the pump, and
it was then forced tightly into the neck of the hard glass tube. By
pouring a little mercury into the cup C the joint could be made
absolutely air-tight.
Examination of Minerals and Rocks.
Several samples of fergusonite, monazite, and samarskite were
first examined, and were found to give quantities of helium up to
1*5 c.c. per gram.
Columbite (a variety of tantalite), an isomorphous mixture of
niobate and tantalate of iron and manganese, gave 1*3 c.c. of gas con-
sisting chiefly of helium.
Pitchblende, containing zirconium, obtained by Dr. Hillebrand from
Colorado, gave 0'36 c.c. of gas per gram, of which 0*3 c.c. was
helium. Another sample gave 0'27 c.c. of helium per gram.
444 Prof. Ramsay and Mr. Travers. The Gaseous
'- Malacone, ZrS04, from Hitteroe in Norway, was the only mineral
in which argon was found. Five grams of the mineral gave 12 c.c.
of gas unabsorbed by caustic soda. After explosion with oxygen,
and absorption of the residual oxygen with phosphorus, about Ol c.c.
of gas remained. The residue was introduced into a tube with
aluminium electrodes which was sealed off from the pump and
attached to a coil giving a discharge sufficiently powerful to heat
the electrodes to a red heat. The nitrogen was quickly absorbed by
the red-hot electrodes, and, as soon as the banded spectrum had dis-
appeared, the lines of helium and argon became visible. The green
line of the helium spectrum was very strong, and the glow in the-
tube was distinctly green.
The argon present was in too large quantity to be attributed to-
accidental leakage of air into the apparatus ; but, in order to confirm
this exceptional result, and also to determine whether the green effect
in the tube was due entirely to the low pressure of the helium, the
experiment was repeated with a larger quantity of the mineral.
With 10 grams of the mineral a quantity of gas was obtained,
which, after removal of nitrogen, gave a yellow glow in the vacuum-
tube ; argon was again present, and its second spectrum could be
brought out very strongly by means of a jar and a spark-gap in the-
secondary circuit. The experiment was repeated a third time with
the same result. This proved conclusively that inalacone contains
both argon and helium.
Cinnabar. — Five grams gay e 0*5 c.c. of gas, which consisted only of
carbon monoxide.
Cryolite. — 7*6 grams gave only a minute bubble of carbon mon-
oxide,
Apatite. — Six grams gave O5 c.c. of a gas consisting wholly of
hydrogen and carbon monoxide.
Baryta-celestine. — No gas was evolved; the pump remained at a
phosphorescent vacuum.
Serpentine. — This specimen was from the Riffelhorn, and has been
analysed by Miss Aston ;* 5 grams gave 4 c.c. of gas which consisted
wholly of hydrogen.
Gneiss, from the Diamirai Glacier, directly below the peak of
Nanga-Parbat, Kashmir, brought home by Dr. Collie : 3 grams gave
6 c.c. of hydrogen.
Scapolite, a silicate of calcium, magnesium, and aluminium, gave
no gas.
Cobalt ore, containing a considerable quantity of manganese
dioxide: — 3'2 grams of mineral, heated alone, gave 35 c.c. of gas-
consisting wholly of oxygen.
* ' G-eol. Soc. Journ.,' 1896, p. 452.
Constituents of certain Mineral Substances and Waters. 445
Lava from Iceland : — Two specimens were examined ; in each case
a little carbon dioxide was obtained.
Some specimens from the Kimberley diamond field, obtained
from Mr. Crookes : —
Blue clay : — A considerable quantity of a mixture of hydrogen and
carbon monoxide was obtained. After explosion with oxygen, no
trace of gas remained.
Coarse-grained gravel and so-called " carbon " gave the same
result.
Examination of Specimens of Meteoric* Iron.
Specimens of meteoric iron were kindly sent for examination by
Dr. Fletcher of the British Museum : —
Greenbrier County meteorite : — Ten grams of metal gave a fairly
large quantity of gas on heating, which consisted wholly of hydrogen.
Toluca meteorite: — One gram gave 2'8 c.c, of pure hydrogen.
Charca meteorite : — One gram gave 0*28 c.c. of hydrogen.
Bancho de la Pila meteorite (' Min. Mag.,' ix, 153) : — One gram
gave 0*57 c.c. of gas. It consisted of hydrogen.
Obernkirchen Meteorite, from Schaumberg-Lippe, Germany, de-
scribed by Wichs and Wohler (' Pogg. Ann.,' vol. 120, p. 509) :— One
gram gave 2*6 c.c. of gas.
The gases from these meteorites were exploded with oxygen, and
were found to contain no trace either of argon or helium, or of
nitrogen. The carbon compounds present were possibly produced
by the decomposition of the oil, &c., with which the shavings of
meteoric iron had become contaminated.
It will be remembered that a previously examined specimen of
meteorite was found to contain both argon and helium.
Examination of the Gases held in Solution "by the Waters of certain
Mineral Springs.
Old Sulphur Well, Harrogate.— One carboy of water gave 650 c.c.
of gas from which, after circulation and sparking, 45 c.c. of argon
were obtained. Spectroscopic examination of the gas proved that
it contained nothing but argon.
Strathpeffer Wells. — One carboy of water gave 1 litre of a gas
which, after sparking and circulation, gave 22 c.c. of pure argon.
The gas was separated from these waters by the method described
by Lord Rayleigh ('Phil. Trans.,' A, vol. 186, p. 220).
Mineral Springs of Cauterets.— The mineral springs of the Hautes
Pyrenees, particularly those containing sulphides, have long been
known to contain considerable quantities of nitrogen. Dr. H. C.
Bouchard, of Paris, has recently (' Compt. Rend.,' vol. 121, p. 392) pub-
lished an account of his examination of gases obtained from the wells
440 Prof. Ramsay and Mr. Travers. The Gaseous
at Cauterets, which he has found to contain a considerable quantity
of a mixture of argon and helium. He appears to have made a rough
spectroscopic examination of the gases, and has stated in his paper-
that some of the lines in the red end of the spectrum do not belong
to the spectrum either of argon or of helium. The author, a medical
man, has dealt with the matter from a purely clinical standpoint, and
his paper contains no data with regard to the supposed new lines.
To obtain samples of these gases, it was necessary to make a journey
to Cauterets, and to visit the wells personally. Taking advantage of
the Easter holidays, we left England provided with twelve tin cylin-
ders, each with a capacity of 2 litres, for the purpose of collecting
samples of gas from as many of the wells as we could obtain admis-
sion to. The management of the baths and wells granted us permis-
sion to visit the actual sources from which the baths, &c., are supplied,
and courteously gave us every assistance, placing at our disposal the
services of men connected with the different establishments. We
were able to obtain samples of gas from four of the springs close to
the town, but, on account of the deep snow, some of the more distant
" sources " were quite inaccessible. The " sources " are for the most
part situated at the end of tunnels driven for some distance into the
hill-side. The water rises from below into tanks beneath the floor of
the tunnels, and is conducted through pipes to the baths. Circular
holes, about 9 inches diameter, in the floor formed the only means of
inspecting the interior of the tanks. The gas appeared to rise with
the water from natural springs in the bottom of the tanks ; it was
this gas that we collected for our investigation. The apparatus
employed is shown in the accompanying figure. A piece of rubber
tube B is fitted on to the lower tap of the cylinder A, which was
then sucked full of water. The taps were then closed, and the cylin-
der fixed in a vertical position, the rubber tube hanging down into
the tank. A second piece of rubber tube, C, was fitted on to the
funnel D, which was lowered into the tank. Water was then drawn
up into the rubber tube, which was immediately slipped over the
nozzle of the upper tap on the tin cylinder. The taps were then
opened, and the funnel brought over some point on the floor of the
tank, from which gas was escaping. The gas rising into the funnel
rapidly replaced the water in the cylinder which escaped back into
the tank by the lower tube. In some of the wells a large quantity of
gas could be collected in a short time, but in others the bubbles rose
only very slowly.
Name of " source." Temp. Time required to fill vessels.
Raillere 39'5° C. One tin in two hours.
Des CEufs 51*0 ,, Three tins in 30 minutes.
Caesar 46'0 „ One tin in four hours.
Espagnol 46'0 „ Three tins in about 15 minutes.
Constituents of certain Mineral Substances and Waters. 447
FIG. 2.
Floor of Tunnel.
We proceeded with the examination of the gases immediately on
our return to London. The gases were transferred to a glass gas-
holder containing potash solution, and circulated over red-hot mag-
nesium and copper oxide. The residual gas was pumped out of the
circulating apparatus, and sparked with oxygen over potash to
remove final traces of nitrogen.
Preliminary Spectroscopic Examination of the Gases.
Raillere. — Argon and helium, helium strong.
Des CEufs. — Argon, with less helium.
Espagnol. — Argon, with helium ; the yellow and green helium lines
very distinct, with jar and spark-gap.
Caesar. — Argon, with a little helium.
The tubes were carefully compared with normal argon and helium
tubes, but no new lines could be detected.
An attempt was made to separate the gas into its constituents by
taking advantage of their relative solubilities. A measured quantity
448 Gaseous Constituents of certain Mineral Substances, fyc.
of the gas was confined over a large quantity of boiled water, and
the residue taken for examination.
Raillere 3'7 c.c. taken, 1*0 c.c. residue.
Des CEufs 8-5 „ 4'0
Csesar 2'2 „ 0'5 „
Espagnol 8*0 ,, (not measured).
The residue showed the helium lines rather more strongly.
The Des CEufs gas was submitted to fractional diffusion by the
method described in the following paper.
The gas was divided into two portions by diffusion through a.
porous plug. These two fractions were then diffused separately, the
light fraction of the heavy gas, and the heavy fraction of the light
gas forming an intermediate fraction, This was again separated by
diffusion into a heavy and a light portion, which were mixed with the
heavy and light fraction obtained in the second stage. The process
was repeated four times, and the resulting fractions, after sparking
with a little oxygen, were rediffused so as to obtain the lightest sixth
of the light fraction, and the heaviest sixth of the heavy fraction.
In a Pliicker tube, the helium line, D3, appeared somewhat stronger
in the light gas, but the difference was not so marked as might have
been expected. Neither of the tubes showed any lines other than
those of the argon or helium spectrum.
The other samples of gas were not submitted to the diffusion pro-
cess, as it did not seem probable that any results of value would be
obtained.
In another paper it is shown that separation of helium from argon
can be effected by taking advantage of the absorption of that gas by
the platinum splashed on to the walls of the tube during the passage
of the discharge. The gas is made to circulate at about 3 mm.
pressure through a vacuum -tube with platinum electrodes, and kept
cool by a water-jacket. The helium, together with any nitrogen or
carbon compounds that may be present, is absorbed by the platinum,
and may be liberated by heating the tube with a Bunsen's burner.
The heavier fraction of the Des CEufs gas, and some of the gas from
the Raillere were treated by this process, and the gas liberated from
the platinum on heating was in each case introduced into a vacuum-
tube with aluminium electrodes. The tube showed a banded spectrum
which disappeared as the nitrogen was absorbed by the heated
aluminium, leaving only normal helium at low pressure and a trace
of argon. If any other gas, other than argon and helium, be present
in the residue from the gas evolved from these various springs, after
removal of the nitrogen, the methods employed have totally failed to
bring it to light so far. It certainly cannot be present in any
measurable quantity.
Some Experiments on Helium. 449
" Some Experiments on Helium." By MORRIS W. TRAVERS,
B.Sc. Communicated by Professor W. RAMSAY, F.R.S.
Received December 30, 1896,— Read February 4, 1897.
In July of last year Professors Runge and Paschen (' Phil Mag./
1895, [ii], vol. 40, pp. 297 — 302) announced their discovery that the
spectrum of the gas from cleveite indicated the presence of two ele-
ments. They also stated that by means of a single diffusion through
an asbestos plug, they had been able to effect a partial separation of
the lighter constituent, which was characterised by the green glow
which it gave under the influence of the electric discharge in a
vacuum-tube, and which was represented in the spectrum by the
series containing the green line, X = 5015'6. Subsequently, at the
meeting of the British Association at Ipswich, Professor Runge
exhibited a tube containing the so-called green constituent; the
colour of the glow differed strongly from that of an ordinary helium
tube, but the gas contained in it was evidently at very low pressure,
as phosphorescence was jusfc commencing. Professor Runge has
since acknowledged that the green effect in the helium tube may be
produced by a change of pressure alone (' Astrophysical Journal,'
January, 1896).
During an exhibition of the spectrum of helium at -the soiree of
the Royal Society on May 9, 1895, it was noticed that one of the
Pliicker tubes which had been running for nearly three hours, had
become strongly phosphorescent. The tube was fitted with platinum
electrodes, and the helium had apparently been absorbed by the
platinum sparked on to the walls of the tube. We observed the same
phenomena to take place on several subsequent occasions, but only in
the case of tubes with platinum electrodes.*
Now, if helium is not a single gas, it must consist of a mixture of
two or more monatomic gases, capable of mechanical separation, and
it is possible that one of its constituents might be absorbed by the
platinum faster than the other. At the end of September, 1895, I
commenced some experimental work on this subject, with the view
of separating the two or more possible constituents from one another.
The results were negative.
I employed in these experiments a piece of apparatus figured
below (fig. 1).
A large Pliicker tube, bent into a U -shape, has two side-tubes, A
and B. The electrodes are of platinum, and project far into the
tube ; the straight parts, which are of thick wire, and about 30 mm.
* So far as I know, this phenomenon was first recorded by Professor Norman
Lockyer (< Eoy. Soc. Proc.,' 1895, vol. 58, p. 193).
450
Mr. W. Travers.
FIG. l.
long, are protected by a sheath of thin glass tube, the spirals at their
ends being of thin platinum wire. The side-tube A is connected, by
means of a tube containing pentoxide of phosphorus, with an appa-
ratus for the introduction of gases into vacuum-tubes (' Trans. Chem.
Soc.,' 1895, p. 686). The tube B is connected with a tap on the Top-
ler's pump. The apparatus was first thoroughly exhausted and
heated by a Bunsen's flame, and then, after closing the tap on B,
helium was introduced at about 3 mm. pressure. The electrodes
were connected with the secondary terminal of a coil, and the cur-
rent was turned on, making a the cathode. A deposit of platinum
quickly appeared on the walls of the tube round a, and the following
changes took place in the colour of the glow : —
1. Yellow, with slight tinge of red.
2. Bright yellow.
3. Yellowish- green.
4. Green ; green line very strong.
5. Green, with phosphorescence.
6. Phosphorescent vacuum ; spark passed between electrodes out-
side the tube.
The tube was then connected with the pump by opening the tap on
B, but, as might have been expected, no trace of gas could be re-
moved. The tap was again closed, and the tube was warmed care-
fully with a Bunsen's burner. The gas was slowly given off from
the platinum, and on passing the discharge, colour- changes were
observed to take place in the glow, from green to yellow.
From this experiment, it was obvious that the whole of the helium
would be absorbed by the platinum splashed off, but it yet remained
Some Experiments on Helium.
451
to be proved that the change in colour in the glow was not due to
the absorption of the yellow constituent more quickly than the green
one.
The vacuum-tube used in the last experiment was again filled with
helium to about 3 mm. pressure, and the discharge was passed till
the glow had become green, and the green line had reached its maxi-
mum intensity. Now, if any separation had taken place, the gas
which had been absorbed by the platinum should contain a large pro-
portion of the yellow constituent of helium, and should give a yellow
glow in a vacuum-tube, even at low pressure. The remaining gas in
the tube was, therefore, removed by pumping, and after closing the
tap on B, the gas was driven off from the platinum, by warming with
a Bunsen's flame. The current was then turned on, and a glow
appeared of the green colour invariably shown by helium at low
pressure. The change of colour in the tube during absorption of the
helium is, therefore, to be entirely attributed to the lowering of the
pressure. In describing these experiments I have used the term
absorption in its general sense, as it is impossible to say at present
whether we are dealing with a case of simple occlusion or not. The
platinum, when it is deposited, is black and non-metallic in appear-
ance, but, on heating, it assumes the colour and general character of
ordinary platinum, and sometimes breaks away from the tube in thin
scales. The change is probably the same as that which takes place
when platinum-black is heated.
In a few of my experiments, I used helium containing traces of
hydrogen, nitrogen, and carbon compounds. In these cases I found
that not only was the helium absorbed, but also the other gases, to a
greater or less extent. Hydrogen is readily absorbed, and next in
order come carbon compounds and nitrogen. Argon is taken up only
in very small quantity ; in fact, this process serves as a method of
separation of helium from argon, even when the helium is present to
the amount of only 2 per cent.
To carry out this separation, the gas is made to circulate at about
3 mm. pressure, through a vacuum-tube of the type used in the last
experiment. To effect this, the Topler's pump is replaced by a Spren-
gel's pump, arranged as shown in fig 2, to deliver the gas removed
from the vacuum-tube back into the tube C. To regulate the supply
of gas entering the apparatus, the tap F was carefully turned, till the
gas bubbled slowly through the mercury contained in the small tube
D. The tap E served as a by-pass during the preliminary pnmping-
out of the apparatus, and was closed during the experiment. By
carefully regulating the quantity of gas which entered the apparatus,
and the rate of flow of mercury in the Sprengel's pump, ifc was
possible to maintain a constant pressure in the apparatus for a long
time.
452
Some Experiments on Helium,
FIG. 2.
To facilitate the absorption of the gases during the experiment,
the vacuum- tube was kept cool by a water-jacket, G, closed at the
bottom by a cork fitting tightly round the tube. When it was
necessary to heat the vacuum-tube, the jacket could be loosened from
the cork, and slipped up the side- tube B, which was bent round, and
extended vertically for about 10 inches in a straight line with the
vacuum-tube.
The gas was made to circulate for about six hours, and at the end
of that time the tap F was closed, the tap E was opened, and the
apparatus thoroughly exhausted. The jacket Gr was then raised, and
the gas expelled from the platinum by heat was pumped off. From
mixtures containing very little helium, a small quantity of that gas
was separated, mixed with a trace of argon.
On the Gases enclosed in Crystalline Rocks and Minerals. 453
Kayser and Friedlander (' Chem. Zeitung,' vol. 9, p. 1529) have
stated that in a vacuum-tube fitted with platinum electrodes, and
containing atmospheric argon, the argon became absorbed by the
deposited platinum, and the tube then showed certain of the helium
lines. I have never been able to absorb argon to more than the very
slightest extent, and though I have often had argon-tubes, which have
become black, owing to the deposition of platinum, through which a
powerful discharge has passed for many hours, I have never noticed
any marked absorption.
A specimen of argon, the lightest fraction obtained from Professor
Ramsay's diffusion experiments, was treated in the manner just
described. After several hours' circulation it was found that the gas
absorbed by the platinum consisted only of argon, and no trace of
helium could be detected. This process has also been applied to the
analysis of the gases from certain mineral springs ; the results of
these experiments form the subject of another paper.
"On the Gases enclosed in Crystalline Rocks and Minerals."
By W. A. TILDEN, D.Sc., F.R.S. Received December 19,
1896,— Read February 4, 1897.
It has long been known* that many crystallised minerals contain gas
enclosed in cavities in which drops of liquid are also frequently
visible. The liquid often consists of water and aqueous solutions,
occasionally of hydrocarbons, and not unf requently of carbon dioxide,
the latter being recognisable by the peculiarities of its behaviour
under the application of heat. The liquid supposed to be carbon
dioxide has been found in some cases to pass from the liquid to the
gaseous state, and therefore to disappear, and to return from gas to
liquid at temperatures lower by two or three degrees than the critical
point of carbon dioxide. This seems to indicate the presence of some
incondensable gas, and as H. Davy found nitrogen in the fluid cavities
of quartz, it seemed probable that the alteration of the critical point
was due to that gas.
My attention was drawn to this subject by the observation that
Peterhead granite, when heated in a vacuum, gives off several times
its volume of gas, consisting, to the extent of three-fourths of it»
volume, of hydrogen (' Roy. Soc. Proc.,' vol. 59, p. 218).
* The chief literature of this subject is contained in the following papers : —
Brewster, < E. S. Edin. Trans.,' 1824, vol. 10, p. 1 ; ' Edin. J. Science,' vol. 6,
p. 115 ; Simmler, < Pogg. Ann.,' vol. 105, p. 460; Sorby and Butler, 'Koy. Soc.
Proe.,' vol. 17, p. 291 ; Yogelsang and Geissler, ' Pogg. Ann.,' vol. 137, pp. 56 and
257 : Hartley, ' C. S. Trans.,' 1876, vol. 1, p. 137, and vol. 2, p. 237, also 1877, vol. 1,
p. 241.
454 Dr. W. A. Tilden, On the Gases enclosed
Since this observation, I find that the presence of hydrogen in
crystalline rocks has been recognised by other observers, notably by
A. W. Wright (' Amer. J. Sci.,' Ser. 3, vol. 12, p. 171). In the course
of a study of the gases from meteorites, Wright obtained from a
certain " trap " rock, the origin and character of which is not stated,
at a low red-heat, " about three-fourths of its volume of mixed
gases, which were found to contain about 13 per cent, of carbon
dioxide, the residue being chiefly hydrogen. Another specimen of
trap containing small nodules of anorthite was examined at the
request of Mr. G. W. Hawes, who had observed gas cavities in a
thin section of the mineral prepared for microscopic examination.
This gave off somewhat more than its own volume of gas, which was
found to contain some 24 per cent, of carbon dioxide."
Professor Dewar and Mr. Ansdell have also examined one or two
rocks in the course of their researches on meteorites (' Roy. Inst. Proc./
1886). They found that both gneiss and felspar, containing graphite,
yield gas, which, upon analysis, was found to have the composition
stated below.
Occluded gas
in volumes
of the rock. , CO2. CO. H2. CH4. N2.
Gneiss 5«32 , 82'38 2'38 13*61 0'47 1-20
Felspar T27 94'72 0'81 2'21 0'61 1-40
Dewar and Ansdell remark that " the small quantity of marsh gas^
no doubt, comes from the disseminated graphite, but the presence of
the hydrogen is more difficult to explain, and requires further inves-
tigation."
I have lately been following up this question, and have obtained
results which present some points of considerable interest. For
materials I have been indebted chiefly to my colleague, Professor
Judd, who has also supplied information as to the probable geological
age of the specimens of rocks and minerals tested. All that I have
examined yield permanent gas when heated in a vacuum. This gas
varies in amount from a volume about equal to that of the rock or
mineral to about eighteen times that volume. It usually consists of
hydrogen in much larger proportion than that found by the observers
just quoted, together with carbon dioxide and smaller quantities of
carbon monoxide and hydrocarbons. Every specimen has been
examined by the spectroscope for helium, but in no case could D3 be
recognised, or any other line which would lead to a suspicion of the
presence of this substance. The gas is very frequently, but not
always, accompanied by water in notable quantities.
The gas is apparently wholly enclosed in cavities which are visible
in thin sections of the rock when viewed under the microscope, but
as they are extremely minute, very little gas is lost when the rock is
in Crystalline Rocks and Minerals.
455
reduced to coarse powder, and as a result of experiment in one or two
cases, I find that practically the same amount of gas is evolved on
heating the rock whether it is used in small lumps or in powder.
In the first series of experiments undertaken with the object of a
rapid survey of the materials, the gases were not completely analysed.
They were collected, measured, the carbon dioxide removed by potash,
and the residue examined by the spectroscope. When ignited in the
air it always burned with a pale flame resembling that of hydrogen.
The table (p. 456) shows the results of these experiments.
A selection of these was then subjected to more careful and exact
analysis. For this purpose fresh masses of the rock were taken,
and the gas extracted in the usual way. The following are the
results : —
C02.
CO.
CH4.
No.
H2.
Granite from Skye •
23-60
6-45
3-02
5 -13
61 '68
Grabbro from Lizard
5 '50
2-16
2-03
1-90
88-42
Pyroxene gneiss, Ceylon
77 '72
8-06
0-56
1-16
12-49
Gneiss from Seringapatam
Basalt from Antrim . .
31-62
32-08
5-36
20-08
0-51
10-00
0-56
1-61
61-93
36-15
To account for the large proportion of hydrogen and carbonic oxide
in these gases, it is only necessary to suppose tha,t the rock enclosing
them was crystallised in an atmosphere rich in carbon dioxide and
steam which had been, or were at the same time, in contact with
some easily oxidisable substance, at a moderately high temperature.
Of the substances capable of so acting, carbon, a metal, or a
protoxide of a metal, present themselves as the most probable.
The reduction of carbon dioxide or of water vapour by carbon
gives rise to the formation of carbon monoxide, and if carbon had
been the agent the proportion of this gas in the mixture must have
been greater than is found to be the case. It is, of course, well
known that carbon dioxide and water vapour are both dissociated at
moderately high temperatures, but the greater part of the liberated
oxygen recombines at lower temperatures, though a small portion
may remain free in the presence of a large quantity of an indifferent
gas or vapour. No free oxygen has been found in any of the gases
analysed.
Direct experiments, made with ferrous oxide (obtained by gently
heating pure chalybite) and with magnetic oxide of iron, show that
while the former, at a red-heat, decomposes both steam and carbon
dioxide quite freely, liberating hydrogen and carbon monoxide, and
becoming itself oxidised into m agnetic oxide ; the latter has no action
VOL. LX. 2 M
456 On the Gases enclosed in Crystalline Rocks and Minerals.
i
f
Volume of
per volu
of rock
ip 9 co ^ o i> o <N N cp in -^ co 9 N o cp 9 9 o 9 9^9
00 Oi *C 00 00 ^O O *O rH O O CO rH j>» Q^ H/* i^j 5<j O^j QO QO <^1 *O "^H
00 CO ' CO i>» CO 00 O •!>• CD Oi C^J 00 ^O -t"*» I?* i>» rH GO 00 00 C^
T"i
1Q O X>* CO O CO ® 00 GO "^ ^-O CO J>» O 00 O ***? O O ^O O
^p-l^rHtM ^2^*GO OiOCOXCOOCO^GOr-irH <M QO^CO
iH CO CO <M CO iH-S^ ^.rH^(M(M<^GOiHrHrH 1> ^Tjt
CO 00 CO 1O* O C^ ^}* CO CO O Ci 00 CO 00 (M iO CO GO *O (^J CO ^O ^1 !>•
iHC<lrHCOOO (MCO(M^' W5COiH(M(M^?COt> l>.^ i^- Q 1> iH CO
J : : ^ ''• 1 ^ : ::!,::::::: . ...
55 • 5 1 .§ ~ t» 5 " o • ...
•g s s e8 - ^ ss o - . -g 5^ .§
erj ^2 - ^42 * ^ § c3 ^
.2" g -2 1 .2"
g 5g Ksjfl gr^ss^s
. s '' " « is " s II =
^£H ^.<ir^i ^PH ^
.^ ::::." '1 ; : : : t ::::::: : : : : «
i ::::: o :::: ° ::::::::: :^ «
^ : : : : : ^ ^ : 5 : g : :^ : | '-§ : :/^ 1 .J . .MS
rS : " S "• * * J J' ^^ 'r^ O ! P
"§ : ; w a :Q-~ c I^»i5
s ^ : ^js : ^c^ WB|^ § 1 fi
^li hlli^lfililJHl I §..«
^.|°I ijij Ajlitilli jij i I -i
03 OQ^-< QuJp4O ^<j^QOWPHfia1firl1 {> O tiJ
• 9
— ,
'CD
nH
• cs
- -- S
:-e.a
s§
| :
rtw : '• j§ : : : iir^'gosS'^^ «^l*
•2 g J '« g .® -2 § 3 N -g ^ S £ -"s S : |
a"1^-^^ g^gj- jS^'Sea^'oSSs"'' cj^^T'S
CScS w?^ ?H JHSnCSj^Q f^ G S-! HJ i; . ^
Q ^ pp O*O O *£ ?i ^b G^fn Q DH cb ^O'PPH
On Lunar Periodicities in Earthquake Frequency. 457
at all upon either steam or carbon dioxide. Magnetic oxide of iron
is the final product of the action of steam or of carbon dioxide at a
high temperature upon metallic iron : —
3Fe + 4H20 = Fe304 + 4H2.
3Fe + 4C02 = Fe304+4CO.
Now, metallic iron has been detected in basalts and some other
rocks by Andrews (' Brit. Assoc. Rep./ 1852, Sections, p. 34), and
by other observers (e.g., G. W. Hawes, * Amer. J. Sci.,' Ser. 3,
vol. 13, p. 33), and I have verified this observation in the case of
the gabbro of Loch Coruisk. But it must be remembered that both
the reactions indicated in the equations just given are reversible, and
therefore the presence of metallic iron along with the magnetic oxide
in such rocks cannot be taken by itself as final proof that the oxide
and the associated gases, hydrogen and carbonic oxide, are the pro-
ducts of the action of steam and carbon dioxide upon metallic iron.
The presence of marsh gas in these rocks and the production of large
quantities of hydrocarbonous gases, as well as liquid petroleum, in
many parts of the earth's surface, tend to support the view, which is
apparently gaining ground, that in the interior of the earth's crust
there are large masses, not only of metal but of compounds of metals,
such as iron and manganese, with carbon. Assuming the existence of
such material, it is easy to conceive how, by the action of water at an
elevated temperature, it may give rise to metallic oxides and mixtures
of hydrogen with paraffinoid and other hydrocarbons. This view was
put forward some years ago by Mendelejeff (" Principles of Chemis-
try," Translation by Kamensky and Greenaway, vol. 1, 364 — 365),
and it has lately received further support from the results of the
study of metallic carbides, which we owe especially to Moissan (' Roy.
Soc. Proc.,' vol. 60, 1896, pp. 156—160).
" On Lunar Periodicities in Earthquake Frequency." By
C. G. KNOTT, D.Sc., Lecturer 011 Applied Mathematics,
Edinburgh University (formerly Professor of Physics,
Imperial University, Japan). Communicated by JOHN
MILNE, F.R.S. Received November 4, 1896,— Read
February 4, 1897.
(Abstract.)
1. Introduction. — The paper is a discussion of Professor Milne's
Catalogues of 8331 earthquakes, recorded as having occurred in
Japan, during the eight years 1885 to 1892 inclusive. These
catalogues, forming vol. 4 of the ' Seismological Journal of Japan,7
458 Prof. C. G. Knott.
are unquestionably the most complete ever constructed for an earth-
quake-disturbed country.
The discussion is really a working out of certain lines suggested in
a paper on " Earthquake Frequency," communicated by me in May,
1885, to the Seismological Society of Japan, and published in vol. 9
of the ' Transactions ' of that Society. In that paper I pointed out
the importance of subjecting earthquake statistics to some strict
form of mathematical analysis, and gave a simple arithmetical
process for separating the annual and semi-annual periods in earth-
quake frequency. The results then obtained have been fully corro-
borated by Dr. C. Davison in his paper " On the Annual and Semi-
annual Seismic Periods " (' Phil. Trans.,' vol. 184, 1893) ; and my
suggestion that the annual period is connected with barometric
pressure is also strongly supported by Dr. Ferd. Seidl in his pam-
phlet 'Die Beziehungen zwischen Erdbeben und Atmospharischen
Bewegungen' (Laibach, 1895). The semi-annual period, which was
first clearly brought into evidence in my earlier paper, does not
admit of a very ready explanation.
In my paper of 1885 I also considered in some detail the various
tidal actions which might reasonably be supposed to have a determin-
ing influence on earthquake frequency. From lack of material it
was not possible at that time to make a satisfactory search for
lunar periodicities ; but the remarkable fulness of information con-
tained in Professor Milne's latest catalogues tempted me to under-
take the labour involved in (first) tabulating the statistics in terms
of lunar periods, and (second) analysing harmonically the tables so
prepared.
2. The Lunar Daily and Half-daily Periods.. — In one of the cata-
logues the earthquakes are classed according to district. Districts
1 to 6 lie on the N.E. and E. coasts of Japan, reckoning from the
north; districts 6 to 11 on the S. coast; and 12 to 15 on the W.
coast. Districts 6 and 7 are the most important, the former being
the region including Tokyo and Yokohama, and the latter the region
including Nagoya, which was the scene of the destructive earthquake
of October 28, 1891. The investigation into a possible lunar daily
period is conveniently based upon this classification into districts.
Had that not been done by Professor Milne the labour involved in
taking into account differences in local time would have been
enormous ; for, to compare the time of occurrence of a recorded
earthquake with the immediately preceding meridian passage of the
moon, it was necessary to apply corrections for longitude and local
time.
The statistics for each district were, in the first instance, separated
out and tabulated according to time of occurrence, estimated in hours
after the immediately preceding passage of the moon. The method
On Lunar Periodicities in Earthquake Frequency. 459
is explained in full in the paper. To lighten in some measure the
labour of the harmonic analysis, certain districts were thrown
together to form a district group. Table I contains the number of
earthquakes in each district or district group, which formed the
material for discussion.
Table I.
Number of Description of
District. earthquakes. district.
1 397 ISTemura.
2—5 627 E. coast.
6 1432 S.E. corner.
7 3632 Nagoya, &c.
8 245 Kii Channel.
9—10 335 E. and S. of Kyushn.
11 384 W. of Kyushu."
12 112 i"
W. coast of Main
13 U8 ( Tl A
14-15 145 J
Of the tabulated numbers for each district or district group, over-
lapping means of every successive five were taken, and these were
divided by the mean of all. The numbers so obtained represent
relative frequencies throughout the lunar day, and are given in
Table II, which also contains a like series for all the earthquakes
taken in combination.
The most important are the frequencies for districts 6 and 7, and
also for all combined. They are shown graphically in the figure
(p. 461).
Each series of numbers was then discussed by harmonic analysis in
accordance with the Fourier expansion
x = 1000 -f £ c« sin » ( — --- |- a,
» = 1 \ 25
where x is 1000 times the relative frequency at time t, estimated
in hours after the meridian passage of the moon, and where the
amplitude c» and the phase an are to be calculated. The amplitudes
and phases for the first four harmonics are given in Table IY.
There is a tendency for the second harmonic amplitude to be
greater than the first, while in half the number it is the greatest of
all. As regards the times of occurrence of the maxima for the
different harmonics, there is no regularity except perhaps in the case
of the second harmonic. In four (1, 6, 7, 8) the maximum of the
second harmonic falls within two hours of the half time between the
upper and lower meridian passage of the moon. In the others it falls
within two hours of the times of upper and lower meridian passage.
2 M 2
460
Prof. C. G. Knott.
On Lunar Periodicities in Earthquake Frequency. 461
462
Prof. C. G. Knott.
Table IV. — The Coefficients c and a, the amplitudes and phase-
coefficients.
District.
<?i.
C2.
<-a.
C4.
04.
02,
«3-
04.
1
94-4
68-7
46-9
16-6
7-85
9-95
2-08
3-43
2-5
29-9
36-5
32-4
35-2
24-2
4-33
0-88
2-95
6
18-4
20-7
29-9
14-6
21-8
11-5
1-79
5-65
7
13-0
16-4
3-17
8-98
6-7
7-9
1-3
6-1
8
54-2
45'8
10-0
6-17
20-2
9-03
2-53
2-07
9—10
65-0
56-9
53-8
5-26
15-9
3-94
3-0
1-92
11
42-8
91-5
32-5
26-0
3-55
4-19
6-91
1-53
12
245-0
233-0
111-5
36-7
3-38
4-93
3'57
4-48
13
73-9
167-0
193-0
7'48
15-1
4-62
3-9
1-09
14-15
175-0
247-6
91-9
41-5
11-2
2-78
2-79
1-75
All
10-3
17-9
10-9
3-97
6-62
7-97
2-42
2-43
A comparison of these times with the times of high water in the
various districts failed to establish any relation. We are forced to
the conclusion that if there be any lunar-diurnal periodicity imposed
upon earthquake frequency, it is the result of tidal stresses acting
directly on the approximately rigid crust of the earth, and not
indirectly through the loading due to the ocean tides.
Because of the comparatively great number of earthquakes the
results for districts 6 and 7 a,re the most important. During the
eight years under discussion, the shocks in district 6 occurred with
normal frequency. All were comparatively small ; none were disas-
trous. On the other hand, the case of district 7 is altogether
peculiar. In general, this is a comparatively quiet district ; but the
great disaster of October 28, 1891, was followed by a vast number of
after-shocks. These show distinct daily and half-daily periodicities,
the latter having the greater amplitude. Thus, from district 6, with
its 1432 earthquakes distributed with fair uniformity over eight
years of normal activity, and from district 7 with its 3632 earth-
quakes, almost wholly included in a short fierce interval of fourteen
months, we obtain very similar evidence as to the existence of a
lunar half-daily period in earthquake frequency.
The results for " All " depend, in the main, upon the statistics for
districts 6 and 7. The curious way in which the comparatively
prominent 1st harmonics of these two districts tend to cancel one
another, is a warning of the danger of lumping together statistics of
different countries or different seismic areas in the search for possible
periodicities.
3. The Lunar Monthly and Fortnightly Periodicities. — There are five
distinct kinds of months recognised by astronomers, namely : —
On Lunar Periodicities in Earthquake Frequency. 463
(1) The anomalistic month (27'545 days).
(2) The tropical month (27'322 days).
(3) The synodic month (29'531 days).
(4) The sidereal month (27'3228 days).
(5) The nodical month (27'212 days).
Of these, the last two cannot be regarded as having any
influence on earthquake frequency, for the only conceivable effect
is a tidal one, and the sidereal and nodical months have no necessary
tidal relations. At the same time the periods of the sidereal and tropical
months are so nearly the same that they can hardly be discriminated
in the lapse of eight years. On the other hand, the anomalistic
month may show itself in earthquake frequency, since the moon in.
perigee has a greater tidal action than when it is in apogee.
Again, because of the moon's variation in declination, being now
north of the Equator, now south, we may reasonably search for a
tropical monthly periodicity. And, finally, the synodic or common
month may make itself apparent, there being possibly a greater tidal
stress when the moon is in syzygy (as in ordinary spring tides)
than when the moon is in quadrature (as in neap tides).
The earthquakes were accordingly tabulated according to these
four months, whose periods differ appreciably ; the nodical month
being also included. For, by analysing the statistics in terms of
both the tropical and nodical months, we may be the better able to
draw conclusions as to the real existence of one or other periodicity.
The relative daily frequencies, as finally reduced, are given in
Table VI, and the curves are shown in the figure.
As in the case of Table II, each of the tabulated numbers is the
mean of five successive numbers, and is regarded as belonging to the
time of the middle one of these five.
It should be mentioned — and the remark applies also to the former
cases — that the number of earthquakes which really occurred during
the last time interval was increased in the proper ratio ; so that the
frequency during this last interval was made comparable with the
frequencies of the other intervals. It was interesting to find how
admirably the number so obtained harmonised with its neighbours of
the first and penultimate interval.
In all cases the obvious aftershocks of any earthquake occurring
on the same day were neglected. The 3000 aftershocks of the great
disaster of October 28, 1891, were also left out.
The earthquakes on which the discussion is based numbered
from 4725 to 4741, the number varying slightly for each monthly
period, since, at the beginning and end of the eight years' interval,
there were always a few, differing for the different months, which did
not make up a complete period, and were, consequently, neglected.
Each series of numbers was analysed harmonically as far as the
464
Prof. C. G. Knott.
Table VI. — "Monthly" Frequencies.
Day.
Anomalistic,
from apogee.
Tropical, from
0° decl. N. to S.
Nodical, from
ascending node.
!
Synodic, from '
full moon.
1
0-919
1-077
0-937
1-064
2
0-945
1-072
0-925
1-081
3
0-976
1-107
0-998
1-029
4
0-980
1-069
1-032
1-000
5
0-999
1-052
1-056
0-961
6
1-013
1-040
1 -068
0-963
7
1-061
1-006
1-103
0-964
8
1-033
0-902
1-045
0-984
9
1-058
0-928
.1-051 0 -980
10
1-064
0-930
1-025
1-002
11
1-023
0-945
1-050
0-999
12
1-002
0 -952
1-047
0-983
13
1-005
1-020
1-037
1-009
14
1-012
1-000
1-011
1-029
15
1-021
0-978
0-964
1-030
16
1-048
0-982
0-901
1-042
17
1-061
0-974
0-858
1-032
18
1-022
0-936
0-896
1-039
19
1-010
0-969
0-901
1-039
20
1-004
0-967
0-939
1 -005
21
1-006
0-964
0-981
0-985
22
1-000
0-975
1-018
0 -965
23
1-017
0-991
1-011
0-918
24
1-004
0-987
1-044
0-905
25
0-952
1 -020
1-028
0-939
26
0-955
1-035
1-028
0-945
27
0-920
1-054
0-992
0-973
28
0-906
1-086
0-994
1-020
29
—
—
—
1-045
30
—
—
—
1-060
first four harmonics, according to a formula identical with that
already given, due regard being paid to the different periods and the
time unit involved. The results are given in Table VII, the phase
coefficients being given in days.
Table VII. — Amplitudes and Phases.
"Montb."
CL.
-
c*.
<*
•
a2.
0;,.
a4.
Anomalistic . ..
46-2
54-7
47-8
40 -7
12-9
23-1
16-5
17 '-2
21
fi
•7
•o
8*5
1 -9
5-2
7-9
6-2
2-4
\odical
49-5
55 -2
28 '3
17 "6
1
•2
7'9
6 "9
2-7
Synodic . .
11*0
52 -1
24 "5
4*7
13
"7
2 '7
7*7
0-6
A study of these tables discloses the presence of certain features
which have no raison d'etre on any rational theory of tidal stress.
On Lunar Periodicities in Earthquake Frequency. 465
The most important of these is the fact that the nodical month,
which has no direct connexion with tidal stress periodicity, is
characterised by harmonic amplitudes greater, on the average, than
those corresponding to the other months. This is particularly
evident in the graphs.
There are, however, other features which favour the hypothesis of
seismic tidal stress, such as the occurrence in the vicinity of perigee
of the Anomalistic 1st Harmonic amplitude ; the lagging, by one
day, behind full and new moon of the Synodic 2nd Harmonic maxima ;
the distinctly greater amplitude of the Synodic 2nd Harmonic as
compared with those of the other harmonics — a fact which is in
accord with the fortnightly succession of spring tides.
It is, certainly, a striking fact that the same statistics which, when
grouped according to an approximately twenty-eight days' period, give
a prominent 1st harmonic should, when grouped according to an
approximately thirty days' period, give a comparatively small 1st
harmonic but a prominent 2nd harmonic.
4. General Conclusions. — The conclusions are summarised under
«ight heads.
(a) There is evidence that the earthquake frequency in Japan is
subject to a periodicity associated with the lunar day.
(6) The lunar half-daily period is particularly in evidence, both by
reason of its relative prominence and the regularity with
which, in each of two groups of the several seismic districts,
its phase falls in relation to the time of meridian passage of
the moon.
(c) There is no certain evidence that the loading and unloading
due to the flow and ebb of ocean tides have any effect on
seismic frequency.
(d) Hence we must look to the direct tidal stress of the moon, in
its daily change, as the most probable cause of a range in
frequency which does not exceed 6 per cent, of the average
frequency.
(e) There is distinct evidence, both as regards amplitude and
phase, of a fortnightly periodicity associated with the times
of conjunction and opposition of the sun and moon.
{/) No definite conclusion can be drawn from the apparent
monthly and fortnightly periodicities which seem to be
associated with the periodic changes in the moon's distance
and decimation, for the simple reason that fully as pro-
minent harmonic components exist when the statistics are
analysed according to the periodic change in the moon's
position relative to the ecliptic, and with this particular
period no tidal stresses can be directly associated.
VOL. LX. 2 N
466 Proceedings and List of Papers read.
(g) Nevertheless, the value of the phase lends some support to the
view that there is a real connexion between the change in
the moon's distance and earthquake frequency, since the
maximum frequency falls near the time of perigee.
(fc) These conclusions have, in comparison with previous similar
investigations, a peculiar value, inasmuch as they are based
upon accurate statistics of fully 7000 earthquakes occurring
within eight years in a limited part of the earth's crust,
throughout which the seismic conditions may be assumed to
be fairly similar from point to point.
February 11, 1897.
The LORD LISTER, F.R.C.S., D.C.L., President, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
Communications from Professor OLIVER LODGE, F.R.S., and Dr.
LARMOR, F.R.S., on the recent discovery by Dr. P. Zeeman of the
effect of a magnetic field on the light emitted by a soda flame, were
read by the Secretary.
The following Papers were read : —
I. "The Oviposition of Nautilus macromphalus." By ARTHUR
WILLEY, D.Sc., Balfour Student of the University of Cam-
bridge. Communicated by ALFRED NEWTON, M.A., F.R.S.,
on behalf of the Managers of the Balfour Fund.
II. "Report to the Committee of the Royal Society appointed to
investigate the Structure of a Coral Reef by boring." By
W. J. SOLLAS, D.Sc., F.R.S., Professor of Geology in the
University of Dublin.
III. " The artificial Insemination of Mammals and subsequent possible
Fertilisation of their Ova.'3 By WALTER HEAPE, M.A., Trinity
College, Cambridge. Communicated by FRANCIS GALTON,
F.R.S.
IV. " On the Regeneration of Nerves." By ROBERT KENNEDY, M.A.,
B.Sc., M.D. (Glasgow).
The Opposition of Nautilus macromphalus. 467
" The Oviposition of Nautilus macrompJialus" By ARTHUR
WILLEY, D.Sc., Balfour Student of the University of
Cambridge. Communicated by ALFRED NEWTON, M.A.,
F.R.S., on behalf of the Managers of the Balfour Fund.
Received February 3, — Read February 11, 1897.
Nautilus macrompJialus is the species of nautilus characteristic of
the New Caledonian Archipelago, which comprises the islands of
New Caledonia, the Isle of Pines, and the Loyalty Group. I took up
my residence on the shores of Sandal Bay, Lifu, in August, 1896.
Having collected a number of Nautilus, I placed them in captivity in
a large native fish-trap, specially fitted up, fed them twice or three
times a week with fish, land-crabs, Palinurus, and Scyllarus, and on
December 5, 1896, commenced to obtain the fertilised ova.
It is not necessary at present to describe the details of manipula-
tion, and I therefore proceed at once to give a brief account of the
more obvious features of the eggs as illustrated by the accompanying
figures. The eggs are laid singly and at night, in concealed situations,
and are firmly attached by a sponge-like reticulate area of attachment
placed towards their hinder inflated extremity, usually on one
face of the egg-case, but sometimes quite posteriorly, to a suitable
surface. I supplied the latter to the Nautilus by fixing pieces of old
sacking to the walls of the fish-basket, leaving loose, overhanging
folds, beneath which the eggs could be well concealed. The fibres
of the sacking were deftly employed by the Nautilus in cementing
their eggs.
The ovum is enclosed within a double casing, an inner closed cap-
sule, and an outer capsule more or less freely open in front. The
material of which the capsules consist is of a bright milk-white
colour, and of firm cartilaginoid consistency. The capsules do not
collapse, but retain their shape when allowed to dry.
For convenience of description, the exposed surface of the egg
may be spoken of as the dorsal or upper side, while the attached side
may be referred to as the lower or ventral side. The outer capsule is
separate from the inner capsule below and for about two-thirds of the
upper side, but is fused with it in the postero-dorsal region. Where
the two capsules are fused together the covering of the ovum is much
thickened.
The egg with outer covering complete is of remarkably large size,
attaining a length of 45 mm., everything included, with a width of
16 mm., and a maximum height of 16'25 mm. The length and the
width are fairly constant in normally shaped eggs, but the height
varies somewhat, some eggs being a good deal flatter than others.
2 N 2
468
Dr. A. Willey.
In fig. 1 an egg is represented as seen in its usual natural attached
position. The depressed or "anterior" end of the egg is, as a rule,
directed vertically upwards. The outer capsule is continued in front
into two thin, translucent, terminal processes. For nearly half the
length of the egg on the upper side the two halves of the outer cap-
sule are separated by a narrow slit from one another and join together
behind the centre of the egg. The dorsal ridge or suture of the
inner capsule can be seen through this slit in the onter capsule. On
the lower side of the egg the two halves of the outer capsule are con-
tinuous across the middle line throughout the length of the egg,
except at the extreme anterior end.
The surface of the egg in the posterior inflated region is smooth,
with a few slight folds like the folds of drapery, giving it a graceful
FiG. 1. — Fertilised egg of Nautilus macromphalus in the natural attached position.
The pectinate ridges and fenestrations, together with the slit in the wall of the
outer capsule, are well seen. The arcuate thickening in the middle of the
posterior half of the egg is due to the fusion of the outer with the inner
capsule. In this ovum the anterior membranous prolongations of the outer
capsule were unequal, the larger of them having the form of a thin flattened
expansion.
FiG. 2.— The same egg from the side, showing the inflated posterior or proximal
portion and the more flattened distal portion, as also the spongy area of
attachment.
The Oviposition of Nautilus macrompkalus. 469
FIGK 3. — The same egg as in the preceding figures, from below. Behind is the
somewhat irregularly shaped spongy area of attachment.
appearance. The anterior depressed region is characterised by the
presence of a number of pectinate ridges and of fenesirations in the
wall of the outer capsule (figs. 1 — 3). Sometimes, however, the pec-
tinations are obscure and the fenestrations may be absent.
Hardly will any two eggs present an exactly similar appearance.
Sometimes there are shred-like processes from the surface of the
outer capsule, lending a more or less tattered appearance to the egg.
In fig. 4 another egg is shown with the above-described slit in the
upper wall of the outer capsule, widened out so as to disclose the
inner capsule to view.
The inner capsule has a regular oval shape with anterior pointed
extremity and a generally smooth surface. Its wall has a finely
striated structure, the striae having a watery appearance. There are
three distinct seams or sutures, representing lines of least resistance,
in the wall of the inner capsule, namely, a median suture on the
upper side (i.e., the side directed away from the attached side of the
egg), and two lateral sutures placed towards the lower surface of the
capsule (figs. 4 — 6).
The dorsal suture is marked by a prominent ridge which is pro-
duced in front beyond the anterior extremity of the main body of
the inner capsule into a slender terminal appendix.
The lateral sutures are marked by less prominent ridges, and are
continued into one another anteriorly, immediately behind the
anterior extremity of the inner capsule. In consequence of the con-
tinuity of the lateral sutures, the lower side of the egg can be raised
up like a cap or an operculum. The inner capsule is often easily
470
Dr. A. Willey.
. 4. — Another egg of N. macromphalus, seen from above, with the longitudinal
slit in the upper wall of the outer capsule widened, out so as. to expose the
inner capsule to view.
. 5. — Inner capsule of another egg to show the dorsal ridge along the dorsal
suture (d. s.) with its anterior terminal prolongation, and the lateral suture
(Z. s.~). o. c., remains of outer capsule.
ruptured along the sutures. In the middle line of the lower surface
of the inner capsule there is a slight longitudinal groove, and other
unimportant grooves often occur. Where the outer capsule is united
to the inner capsule there is usually a depression or flattening in the
wall of the latter.
The vitellus (tig. 6) does not fill the entire cavity of the inner
capsule, but is surmounted by a layer of colourless, somewhat cloudy,
viscid albumen which, is massed up, as it were, at the two extremities
of the egg. The yolk is of a rich brown colour, of very fluid con
sistency, and sub-translucent. The surface of the vitellus is quite
smooth. The length of the inner capsule is about 26 mm., while that
of the enclosed vitellus is 17 mm.
I am not in a position to say much, about the embryonic area at
present, but I have observed an area pellucida about the middle of
The Oviposition of Nautilus macrornphalus. 471
Fia. 6. — The inner capsule of the same egg, seen from below (i.e., from the side
directed towards the surface of attachment). Half the lower wall of the
capsule has been removed by slitting along one of the lateral sutures, and
along the median groove (mentioned in the text), to show the brown-coloured
vitellus lying in the capsule. The continuity of the lateral sutures (I. s.) in
front is well seen. The shaded area represents a depression which occurred in
the wall of the inner capsule in the region of the area of attachment of the
outer capsule.
the lower surface of the vitellus in an egg which had been allowed to
develop for twenty-four hours after being first seen. The large quan-
tity of yolk points to the occurrence of a long period of incubation.
Sometimes the capsules of the egg are malformed, and, on opening
such an egg, the vitellus is found to be already ruptured.
From the fact that in New Britain I obtained mature males of
Nautilus pompilius, carrying a spermatophore in the cephalic region
throughout the year, I came to the conclusion that the reproduction
of Nautilus took place all the year round. It now seems probable
that the breeding of Nautilus, as of so many other forms, is subject
to a definite law of periodicity.
Finally, it may be mentioned that N. macromphalus varies with
regard to the position of the spadix on the right or left side, and
also as to the origin of the siphuncular artery, in the same way as
N. pompilius does. The male of N. macromphalus carries a spermato-
phore in the same position as in N. pompilius ; and, in fact, the only
essential difference between the two species that I know of at present,
is the difference between the shells in the umbilical region.
472 Dr. R. Kennedy.
" On the Regeneration of Nerves." By ROBERT KENNEDY,
M.A., B.Sc., M.D., Glasgow. Communicated by Professor
McKENDRiCK, F.R.S. Received January 7, — Read February
11, 1897.
(Abstract.)
The author treats the subject under the following heads : —
I. A short historical and critical review of the books and papers
which have appeared on the subject from the time of Cruik-
shank (1776).
II. Clinical reports of four cases of secondary suture of nerves as
follows : —
1. Suture of the median and ulnar nerves six and a half months
after division in the middle of the forearm. There was total loss of
sensation and motion in the distribution in the hand, and marked
atrophic changes. Three days after the operation, sensation com-
menced to return ; by the nineteenth day, touch was correctly localised
on all parts of the fingers ; and by the end of the first month, sensa-
tion was almost perfect. Improvement in motion was slow and
imperfect.
2. Suture of the median three months after complete division
above the wrist. Sensation was lost in the median distribution, and
opposition of the thumb was impossible. There was marked
atrophy of the thenar eminence. Two days after the operation,
sensation commenced to return. Both sensation and motion speedily
improved, and by the end of a year recovery was almost perfect.
3. A case in which the median, musculo-spiral, and ulnar were
involved in cicatricial tissue at the seat of fracture at the elbow
joint ; excision of portions from median and musculo-spiral, and
suture, two months after accident. There was total anaesthesia in
the distribution of the affected nerves, and paralysis of the muscles.
Sensation, after the operation, commenced to return on the fourth
morning, but made slow progress. The case was under observation
for six weeks only, at which time no improvement had occurred in
motion, but sensation was present in the fingers.
4. Suture of the ulnar nerve eighteen months after division.
Sense of pain was totally lost in the ulnar distribution. Five days
after the operation, sense of pain returned in the little finger, and by
six weeks, sensation was almost perfect, although motion had not
improved.
III. Deductions from the results of operation.
From the above results the author concludes that the early return
On the Regeneration of Nerves. 473
of sensation must be regarded as indicating a restored conduct! vity
of the divided nerve. He holds that the theories which have hitherto
been advanced to account for early return of sensation apart from
reunion of the nerve, are inapplicable to cases where early return of
sensation occurs from suture, performed after the lapse of several
months from the time of section. The imperfect return of motion he
takes to be fully explained by the fact that the muscles have under-
gone great trophic change, or indeed total destruction, and that,
therefore, their restitution must be slow, or may even be impossible.
IV. Microscopical examination of the portions removed previous to
suture.
Both the central and peripheral ends of nerves which had not
reunited in any way, contained young nerve fibres grouped in bundles,
each bundle containing, as a rule, many fibres. The fibres contained
an axis-cylinder lying in the centre of a clear, well-defined zone,
which, again, contained a granular, myeline deposit, while spindle-
shaped nuclei were attached to the sides of the fibres at frequent
intervals. Where the ends of the nerve were united by a cicatricial
segment without conductivity being restored, the examination of the
segment showed a dense network of connective tissue containing in
its meshes bundles of young fibres.
The portions excised from the nerves involved at the seat of frac-
ture showed at their central ends a normal structure, but elsewhere
no trace of old myeline fibres, nor of degenerated fibres ; but the
section was made up of young fibres in bandies, which bundles were
of only slightly greater diameter than the old myeline fibres, and
often surrounded by a delicate sheath. At the point of transition
from old to young fibres, many of the old myeline fibres contained
an enlarged nucleus, with one or two distinct young fibres lodged
between the sheath of Schwann and the myeline sheath. In other
cases the number of young fibres lying in a similar position was
greater. All stages up to complete replacement of the old myeline
sheath and axis-cylinder by young fibres were found.
Y. Deductions from the microscopical examination.
1. Degeneration : —
(a) That there is no evidence of ascending degeneration of the
kind described by Krause after interruption of a nerve.
(6) That the old axis-cylinder and myeline sheath are destroyed in
the peripheral segment, and in the ultimate portion of the central
segment.
2. Regeneration : —
(a) That young nerve fibres are developed in the peripheral seg-
ment, as well as in the end of the central segment, and that even
while there is no connexion between the two ends.
474 Proceedings and List of Papers read.
(6) That these young nerve fibres originate within the old sheath, of
Schwann from the protoplasm and nucleus of the interannular seg-
ment. The spindle-cells formed from the protoplasm and nuclei of
the interannular segments elongate and unite to form protoplasmic
threads, with the elongated nuclei attached to their sides. The
•central portion of the protoplasmic thread develops into the axis
cylinder, while myeline is deposited in drops in the protoplasm
surrounding the newly formed axis-cylinder. The protoplasm in
which the myeline is deposited remains with the nucleus as the neuro-
blast of the new interannular segment.
(c) That so long as conductivity of the nerve is not re-established,
the development of the fibres proceeds only to a certain stage, and
as the new fibres three months and eighteen months subsequent to
division present identical characters, this stage may be regarded as a
resting stage, depending for its further development on re-establish-
ment of function.
(d) That cicatricial intercalary segments reuniting the ends of a
divided nerve may be permeated by young fibres from end to end
without re-establishment of function, if the amount of cicatricial
connective tissue present in the mass is sufficient by its pressure to
prevent the passage of impulses.
February 18, 1897.
The LORD LISTER, F.R.C.S., "D.C.L., President, in the Chair.
A List of the Presents received was laid on the table, and thanks
ordered for them.
%
The following Papers were read : —
1. " On the Iron Lines present in the Hottest Stars. Preliminary
Note." By J. NORMAN LOCKYER, C.B., F.R.S.
II. " On the Significance of Bravais' Formulas f Dr Regression, &c.,
in the case of Skew Correlation." By Gr. UDNY YULE. Com-
municated by Professor KARL PEARSON, F.R.S.
III. " Mathematical Contributions to the Theory of Evolution. On
a Form of Spurious Correlation which may arise when
Indices are used in the Measurement of Organs." By KARL
PEARSON, F.R.S.. University College, London.
IV. "Note to the Memoir by Professor Karl Pearson, F.R.S., on
Spurious Correlation." By FRANCIS G-ALTON, I .R.S.
On the Iron Lines present in the Hottest Stars. 475
" On the Iron Lines present in the Hottest Stars. Preliminary
Note." By J. NORMAN LOCKYER, C.B., F.R.S. Received
January 25,— Read February 18, 1897.
In continuation of investigations communicated to the Royal
Society in 1879* and 1881, f on the effect of high-tension electricity
on the line spectra of metals, I have recently used a more powerful
current and larger jar surface than that I formerly employed.
The former work consisted in noting (1) the lines brightened in
passing a spark in a flame charged with metallic vapours, and (2) the
lines brightened on passing from the arc to the spark. It was found, in
the case of iron, that two lines in the visible spectrum at 4924*1 and
5018'6, on Rowland's scale, were greatly enhanced in brightness, and
were very important in solar phenomena.
The recent work carries these results into the photographic region.
The result is interesting and important, since seven additional lines
have been found to have their brightness enhanced at the highest
temperature. These, as well as the two previously observed, are
shown in the following table, which also indicates the behaviour of
the lines under different conditions, as observed by Kayser and
Runge (K and R) and myself (L) in the arc, and by Thalen (T)
and myself in sparks : —
Lines of Iron which are enhanced in Spark.
Wave- InteMity
le"Sth- flame.
1
I
Intensity
in arc
(KandE).
Max. = 10.
Length in
arc (L).
Max. = 10.
Intensity
in spark (T).
Max. = 10.
Intensity
in hot spark
(L).
Max. = 10.
4233 -3 —
1
_
_
4
4508 -5
1
—
—
4
4515-5
1
—
.• . —
4
4520 -4
4522-8
1
1
3
z
I
. 4549-6
4
5
—
6
4584-0
2
4 •
—
7
4924 -1
1
3
6
6
5018-6 —
4
—
6
!
Combining this with former results, we seem justified in conclud-
ing that, in a space heated to the temperature of the hottest spark,
and shielded from a lower temperature, these lines would constitute
the spectrum of iron.
* < Roy. Soc. Proc.,' 1879, vol. 30, p. 22.
f Ibid., 1881, Tol. 32, p. 204.
476 On the Iron Lines present in the Hottest /Stars.
Defining the hottest stars as those in which the ultra-violet spec-
trum is most extended, it is known that absorption is indicated by
few lines only. In these stars iron is practically represented by the
enhanced lines alone ; those which build up, for the most part, the
arc spectrum are almost or entirely absent.
The intensities of the enhanced lines in some of the hottest stars
are shown in the appended diagram, and, for the sake of comparison,
the behaviour of a group of three lines which are among the most
marked at lower temperatures, is also indicated. In addition, the
diagram shows the inversion in intensities of the spark and arc
lines in the spectrum of a relatively cool star — such as a-Orionis.
6EU.ATRIX
VORIONI8
j .
'
OCCYONI
1 1 I
ENHANCED
1.INC8
AUC UNES •
The facts illustrated by the diagram indicate that the enhanced
lines may be absent from the spectrum of a star, either on account of
too low or too high a temperature. In the case of low temperature,
however, iron is represented among the lines in the spectrum, but at
the highest temperature all visible indications of its presence seem
to have vanished.
This result affords a valuable confirmation of my view, that the
arc spectrum of the metallic elements is produced by molecules of
different complexities, and it also indicates that the temperature of
the hottest stars is sufficient to produce simplifications beyond those
which have so far been produced in our laboratories.
On Bravais' Formula in the case of Skew Correlation. 477
" On the Significance of Bravais' Formulae for Regression, &c.,
in the case of Skew Correlation." By G. UDXY YULE.
Communicated by Professor KARL PEARSON, F.R.S.
Received December 14, 1896,— Read February 18, 1897.
The only theory of correlation at present available for practical
use is based on the normal law of frequency, but, unfortunately, this
law is not valid in a great many cases which are both common and
important. It does not hold good, to take examples from biology,
for statistics of fertility in man, for measurements on flowers, or for
weight measurements even on adults. In economic statistics, on the
other hand, normal distributions appear to be highly exceptional :
variation of wages, prices, valuations, pauperism, and so forth, are
always skew. In cases like these we have at present no means of
measuring the correlation by one or more " correlation coefficients "
such as are afforded by the normal theory.
It seems worth while noting, under these circumstances, that in
ordinary practice statisticians never concern themselves with the
form of the correlation, normal or otherwise, but yet obtain results of
interest — though always lacking in numerical exactness and fre-
quently in certainty. Suppose the case to be one in which two
variables are varying together in time, curves are drawn exhibiting
the history of the two. If these two curves appear, generally
speaking, to rise and fall together, the variables are held to be corre-
lated. If on the other hand it is not a case of variation with time,
the associated pairs may be tabulated in order according to the
magnitude of one variable, and then it may be seen whether the
•entries of the other variable also occur in order. Both methods are
of course very rough, and will only indicate very close correlation,
but they contain, it seems to me, the point of prime importance at
all events with regard to economic statistics. In all the classical
examples of statistical correlation (e.g., marriage-rate and imports,
corn prices and vagrancy, out-relief and wages) we are only
primarily concerned with the question is a large x usually associated
with a large y (or small y) ; the further question as to the form of
this association and the relative frequency of different pairs of the
variables is, at any rate on a first investigation, of comparatively
secondary importance.
Let Ox, Oy be the axes of a three dimensional frequency-surface
drawn through the mean 0 of the surface parallel to the axes of
measurement, and let the points marked (x) be the means of succes-
sive ^-arrays, lying on some curve that may be called the curve of
regression of x on y. Now let a line, RR, be fitted to this curve,
478 Mr. G. U. Yule. On the Significance of Bravais Formula?
*\
y
V
A
»\
*\
*\
X
\ —
V
V
32
. \*
\
3
« \
\^
subjecting tlie distances of the means from the line to some minimal
condition. If the slope of RR is positive we may say that large
values of x are on the whole associated with large values of t/, if it is
negative large values of x are associated with small values of y.
Further, if the slope of RR to the vertical be given we shall have a
measure of a rough practical kind of the shift of the mean of an
#-array when its type y is altered. The equation to RR conse-
quently gives a concise and definite answer to two most important
statistical questions. It is also evident that if the means of the
arrays actually lie in a straight line (as in normal correlation), the
equation to RR must be the equation to the line of regression.
Let n be the number of observations in any a?-array, and let d be
the horizontal distance of the mean of this array from the line RR.
I propose to subject the line to the condition that the sum of all
quantities like nd~ shall be a minimum, i.e., I shall use the condition
of least squares. I do this solely for convenience of analysis ; I do-
not claim for the method adopted any peculiar advantage as regards
the probability of its results. It would, in fact, be absurd to do soy
for I am postulating at the very outset that the curve of regression is
only exceptionally a straight line ; there can consequently be no
meaning in seeking for the most probable straight line to represent
the regression.
Let x, y be a pair of associated deviations, let a be the standard
deviation of any array about its own mean, and let
for Regression, <J*c., in the case of Skew Correlation. 47 $•
X=a + lY
be the equation to BR. Then for any one array
Hence, extending the meaning of S to summation over the whole
surface
But in this expression S(w<r) is independent of a and 6, it is, in facty
a characteristic of the surface. Therefore, making S(ncF) a minimum
is equivalent to making
a minimum. That is to say, we may regard our method in another
light. We may say that we form a single-valued relation
x = a + by
between a pair of associated deviations, such that the sum of the
squares of our errors in estimating any one x from its y by the
relation is a minimum. This single-valued relation, which we may
call the characteristic relation, is simply the equation to the line of
regression B/R. There will be two such equations to be formed
corresponding to the two lines of regression.
The idea of the method may at once be extended to the case of
correlation between several variables xit x^ xz, &c. Let n be the
number of observations in an array of a?i's associated with fixed
values X2, X3, X4, &c., of the remaining variables, let a^ be the
standard deviation of this array, and let d be the difference of its
mean from the value given by a regression equation
Xi = a13X;j + ^3X3 4-014X4 + ......
Then, as before, we shall determine the coefficients a12, a13 a14, &c., so
as to make Sndz a mini mum. But this is again equivalent to-
making
a minimum for
S {a?! - (aiaajj + a18ara + Wi + ....) }8 = S 0
Hence, we may say that we solve for a single- valued relation
between our variables ; the relation being such that the sum of the
squares of the errors made in estimating ajx from its associated
values a?2, 3-3, &c., is the least possible. In the case of normal correla-
480 Mr. G. U. Yule. On the Significance of Bravais Formula
tion this " characteristic relation " must become the " equation of
regression " which gives the means of any a^-array, as only in this
way can Snd* be made a minimum, i.e., zero.
It might be said that it would be more natural to form a " charac-
teristic relation " between the absolute values of the variables and
not their deviations from the mean. This may, however, be most
conveniently done by working with the mean as origin until the
characteristic is obtained, and then transferring the equation to zero
as origin. It would be much more laborious and would only lead to
the same result if zero were used ab initio as origin.
We may now proceed to the discussion of the special cases of two,
three, or more variables. The actual formulee obtained are not, it
will be found, novel in themselves, but throw an unexpected light
on the meaning of the expressions previously given by Bravais* for
the case of normal correlation.
(1) Case of Two Variables. — Since x and y represent deviations
from their respective means, we have, using S to denote summation
.over the whole surface,
S(«) = 8(2,) = o.
'The characteristic or regression equations which we have to find are
•of the form
Taking the equation for x first, the normal equations for a\ and l\
are
SO) = Na1+61SQ/) 1
'
N being the total number of correlated pairs. From the first of
ihese equations we have at once
az = 0.
From the second
"To simplify our notation let us write
SO2) = N^2.
so*/) =
<TI and <?2 are then the two standard-deviations or errors of mean
* " Memoires par divers Savants, " 1846, p. 255, and Professor Pearson's paper
.on " Regression, Heredity, &c." ' Phil. Trans.,' A, vol. 187 (1896), p. 261 et seq.
for Regression, #<?., in the case of Skew Correlation. 481
square, r is Bravais' value of the coefficient of correlation. Be-
writing 6i in terms of these symbols, we have
61 ~ r
"i
(3}
02
b*-r°* .
(ft.
Similarly, 03 = 0,
But the expressions on the right of (3) and (4) are the values
obtained by Bravais on the assumption of normal correlation for the
regression of x on y, and the regression of y on x. That is to say,
the Bravais values for the regressions are simply those values of b\
and bz, which make
S«— 62 and S-
respectively minima, whatever be the form of the correlation between the
two variables. Again^ whatever the form of the correlation, if the
regression be really linear, the equations to the lines of regression are
those given above (as we pointed out in the introduction). This
theorem admits of a very simple and direct geometrical proof.
Let n be the number of correlated pairs in any one array taken
parallel to the axis of x, and let 0 be the angle that the line of
regression makes with the axis of y. Then, for a single array,
or extending the significance of S to summation over the whole
surface,
S(xy) = tf tan 0er22,
that is,
tan 9 = r *-± .
ffZ
In any case, then, where the regression appears to be linear, Bravais*
formulce may be used at once without troubling to investigate the
normality of the distribution. The exponential character of the surface
appears to have nothing whatever to do with the result.
To return, again, to the most general case, we see that both
coefficients of regression must have the same sign, namely, the sign
of r. Hence, either regression will serve to indicate whether there is
correlation or no, for there is no reason, a priori, why the values of
61 and bz, as determined above, should be positive rather than
negative. But, nevertheless, the regressions are not convenient
measures of correlation, for, on comparing two similar cases, we may
find, say,
bi > DU 62 < &'«»
VOL. LX. 2 o
482 Mr. G. U. Yule. On the Significance of Bravais9 Formula1
where &i&2, &'i&'2 are the regressions in the two cases. To which
distribution are we, in such a case, to attribute the greater corre-
lation ? Bravais' coefficient solves the difficulty, we may say, in
one way, by taking the* geometrical mean of the two regressions as
the measure of correlation. It will still remain valid for non-normal
correlation. But there are other and less arbitrary interpretations
even in the general case.
Suppose that instead of measuring x and y in arbitrary units we
measure each in terms of its own standard deviation, Then let us
write
X- = fy~ ......... ............. (5),
and solve for p by the method of least squares. We have omitted a
constant on the right-hand side, since it would vanish as before. We
have, at once,
That is to say, if we measure x and y each in terms of its own
standard deviation, r becomes at once the regression of x on y, and
the regression of y on x. The regressions being, in fact,, the funda-
mental physical quantities, r is a coefficient of correlation because it
is a coefficient of regression.* ,
Again, let us form the sums of the squares of residuals in equations
(1) and (5). Inserting the values of 6l5 62, and />, we have —
(7).
Any one of these quantities, 'being the sum of a series of squares,
must be positive. Hence r cannot be greater than unity. If r be
equal to unity, or if the correlation be perfect, all the above three
sums become zero. But
can only vanish if
x y
-- = 0
<T2
in every case, or if the relation hold good,
* That the regression becomes the coefficient of correlation when each deviation
is measured in terms of its standard-deviation in the case of normal correlation has
been pointed out by Mr. Francis G-alton. Vide Pearson ' Phil. Trans.,' A, vol. 187,
p. 307, note.
for Regression, fyc., in the case of Skew Correlation. 483
^ = ^2 = ^=, . ;=±f-1 (8)v
2/1 2/3 2/3 "2
the sigh of the last term depending on the sign of r. Hence the
statement that two variables are "perfectly correlated "implies that
relation (8) holds good, or that all pairs of deviations bear the same
ratio to one another. It follows that in correlation, where the means
of arrays are not collinear, or the deviation of the mean of the array
is not a linear function of the deviation of the type, r can never be
unity, though we know from experience that it can approach pretty
closely to that value. If the regression be very far from linear, some
caution must evidently be used in employing r to compare two diffe-
rent distributions.
In the case of normal correlation, o-^l— r2 is the standard devia-
tion of any array of the x variables, corresponding to a single type of
2/'s. <ra^T— r8 is similarly the standard deviation of any array of
the y variables, corresponding to a single type of o>'s. In the general
case, the first expression may be interpreted as the mean standard
deviation of the ^-arrays from the line of regression, and the second
expression as the mean standard deviation of the y-arrays from the
line of regression. Otherwise we may regard
— r2
as the standard error made in estimating x from the relation
x = %,
and
as the standard error made in estimating y from the relation
y = M,
these interpretations being independent of the form of the correla-
tion.
(2.) Case of Three Variables.
Let the three correlated variables be Xj, X2, X3, and let #l5 a?2, #3
denote deviations of these variables from their respective means. Let
us write, for brevity,
NV, S(>2a) =
2 o 2
484 Mr. G. U. Yule. On the Significance of Bravais Formula?
Our characteristic or regression-equation will now be of tlie form
613 and 613 being the unknowns to be determined from the observations
by the method of least squares. I have omitted a constant term on
the right-hand side, since its least-square value would be zero as
before. The two normal equations are now —
or replacing the sums by the symbols defined above, and simplify-
ing —
= 612<r2-f &i3r3303 1
whence
-*« - 2
(11).
&13 = "
That is, the characteristic relation between %i and x*x-s is —
Now Bravais showed that if the correlation were normal, and we
selected a group or array of Xi's with regard to special values hz and
h3 of #2 and #3, then 7^ being the deviation of the mean of the selected
Xi's from the Xrmean of the whole material,
where &12 and 613 have the values given in (11). But evidently the
relation is of much greater generality ; it holds good so long as ^ is
a linear function of 7i2 and &3, whatever be the law of frequency.
Further, the values of biz and &13 above determined, are, under any
circumstances, such that
is a minimum. If we insert in this expression the values of 612 and
613 from (11), we have, after some reduction,
(13),
for Regression, $c., in the case of Skew Correlation. 485
say. In normal correlation o^x/l— R^ is the standard deviation of
an Xrarray, corresponding to any given types of X2 and X8. In
general correlation it may be regarded as the mean standard deviation
of the Xx-arrays from the plane
or as the standard error made in estimating Xi from xz and #3 by
relation (12).
The quantity R is of some interest, as it exactly takes the place of
r in the residual expressions (7). R! may, in fact, be regarded as a
coefficient of correlation between x\ and (#vc3) ; it can only be unity
if the linear relation (9) or (12) hold good in every case.
The quantities 612, &i3, &c. (the others may be written down by
symmetry), may be termed the net regressions of Xi on #2, Xi on #3,
&c. If we write 2 for 1 and 1 for 2 in the value of 612, we have
621 being the the net regression of xz on xt. In normal correlation,
612 and 62i are the regressions for any group of X^s or X2's associated
with a fixed type of X3's. Hence, in this case (normal correlation),
the coefficient of correlation for such a group is the geometrical mean
of the two regressions, or
a quantity that may be called the net coefficient of correlation
between a?x and cc2.* The similar net coefficients between x\ and #3,
Xz and ofc, may be written down by interchanging the suffixes.
In normal correlation yo12 is quite strictly the coefficient of correla-
tion for any sub-group of X/s and X2's, whatever the associated type
of X3's. In generalised correlation this will not be so, and />12 can
only retain an average significance.
The method does not appear to be capable of investigating changes
in the net coefficient as we pass from one type to another, but it may
be noted that whatever the form of the correlation, pl2 retains three
of the chief properties of the ordinary coefficients : (1) it can only be
* My quantities, J12, bls, &c., were termed by Professor Pearson (" Regression
&e.," ' Phil. Trans.,' A, vol. 187 (1896), p. 287), "Coefficients of double regression,"
and quantities like i^-^, #13--, &c., "coefficients of double correlation." My
<TI ffl
quantities p he did not use. Having named the p's " net correlation," it seemed
most natural to rename the J's " net regressions," as the Vs and p's are correspond-
ing quantities.
Some of my results given above were quoted by Professor Pearson in his paper
(loc. cit., notes on pp. 268 and 287).
486 Mr. G. U. Yule. On the Significance of Bravais* Formula:
zero if both net regressions are zero; (2) it is a symmetrical func-
tion of the variables ; (3) it cannot be greater than unity ; for,
by (13),
or adding r^V^3 to both sides, and transferring r132 to the right-hand
side
< (l-r132)(l-r232).
If any two coefficients, say r12r13, be supposed known, the inequality
we have used above will give us limits for the value of the third,.
Throwing it into the form
.
we have r^ must lie between the limits
± \/na2r132 -^ r122 - r132 + 1.
The values of these limits for some special cases are collected in
the following table : —
Yalues of r13 and r13. Limits of r«s«
fia = **i3 = 0
r« = ?*i3 = ±1
r« = + 1> ris =
r12 = 0, r13=
r« = 0, r13 =
r12 = r13= ±r
r13 = r13 = ± v/05= 0'707
r12 = + v/0'5 r12 .= —
V
0
+1
— 1
0
1 and 2rz— 1
2rz— 1 and — 1
0 and 1
0 ., —1
One is rather prone to argue that if A be correlated with B, and B
with C, A will be correlated with C. Evidently this is not necessary.
A may be positively correlated with B, and B positively correlated
with C, but yet A may, in general, be negatively correlated with C.
Only, if the coefficients (AB) and (BC) are both numerically greater
thanO'707, can one even ascribe the correct sign to the (AC) corre-
lation.
It is evident that one would, in general, expect to make a smaller
standard error in estimating x\ from the two associated variables #2
and a'3, than in estimating it from one only, say a°2. But it seems
desirable to provevthis specifically, and to investigate under what
conditions it will hold good. The necessary condition is —
ri22 + r138— 2r12r23r13 2
for Regression, fyc., in the case of Skew Correlation. 487
that is,
2— 2r12r13r23 > r12a-r122r132,
> 0. ;
or
But (r13— ri2r23) is the numerator of /»H, the net coefficient of corre-
lation between x\ and #3. Hence the standard error in the second
case will be always less than in the first, so long as p13 is not zero.
The condition is somewhat interesting.
To take an arithmetical example, suppose one had in some actual
case • > r<*> 'Jo $ • •
r12= +0-8 >i t-
r23= + 0-5 r13= +0-4.
One might very naturally imagine that the introduction of the third
variable- with a fairly high correlation coefficient (0*4) would con-
siderably lessen the standard deviation of the x^- array ; but this is
not so, for
0-4— (0-5X0-8)
/>13~ -/0-75XO-86" :°'
sb the third variable would be of no assistance.
III. Case of Four Variables.
This case is, perhaps, of sufficient practical importance to warrant
our developing the results at length as in the last.
If a?i, %2, it's, a'4, be the associated deviations of the four variables
from their respective means, the characteristic equation will be of the
form
(14).
The normal equations for the fr's are, in our previous notation,
Hence
r12 r,3 r24
r13 1 rsi
r24
r23 1
(15),
and so on for the others, b^ 613, &c., we may call the net regressions
of xi on ajz, ajj on a?3, &c., as before. By parity of notation^we have
488 On Bravais' Formula in the case of Skew Correlation.
12 ?*23 ?*24
1 fsi
^34 1
and we may again call
tlie net coefficient of correlation between Xi and #2. Expanding the
determinants, we have, in fact,
........ (16).
There are six such net coefficients, />12, />13, /314, p^ pUt pu. The
above values of the regressions are again those usually obtained on
the assumption of normal correlation.* The net correlation pn
becomes, on that assumption, the coefficient of correlation for any
group of the %i wz variables associated with fixed types of #3 and #4.
If we write
we have, after some rather lengthy reduction,
where
1
4) J
In normal correlation, o-!-/! — ^i2 is the standard deviation of all ajr
arrays associated with fixed types of xz, »3, and #4. In general corre-
lation, it is most easily interpreted as the standard error made in
estimating 0*1, by equation (14), from its associated values of x2, #3,
and x^
As in the case of three variables, the quantity R may be considered
as a coefficient of correlation. It can range between +1, andean
only become unity if the linear relation (14) hold good in each indi-
vidual instance.
We showed at the end of the last section that the standard error
made in estimating x1 from the relation
*' Professor Pearson, " Eegression, Heredity, and Panmixia." ' Phil. Trans.,'
> Yol. 187 (1896), p. 294.
Mathematical Contributions to the Theory of Evolution. 489
was always less than the standard error when only xz was taken into
account, unless
/>13 = 0.
We may now prove the similar theorem that when we use three
variables, xzi «3, *i, on which to base the estimate, the standard error
will be again decreased, unless
Pli = 0.
The condition that S(?r), in our present case, shall be less than
S(r2) in the last, is, in fact,
22 + r132 + rM»- n^-r^Vu2 -r13V242 -|
Wl—
J
132— 2r12r13r23)(l--r232— r242— ?'
This may be finally reduced to —
0,
that is />142 > 0.
The treatment of the general case of n variables, so far as regards
obtaining the regressions, is obvious, and it is unnecessary to give it
at length.
We can now see that the use of normal regression formulae is quite
legitimate in all cases, so long as the necessary limitations of inter-
pretation are recognised. Bravais' r always remains a coefficient of
correlation. These results 1 must plead as justification for my use of
normal formulas in two cases* where the correlation was markedly
non-normal.
" Mathematical Contributions to the Theory of Evolution. — On
a Form of Spurious Correlation which may arise when
Indices are used in the Measurement of Organs." By
KARL PEARSON, F.R.S., University College, London. Re-
ceived December 29, 1896,— Read February 18, 1897.
(1) If the ratio of two absolute measurements on the same or
different organs be taken it is convenient to term this ratio an index.
If u =/!(#, y) and v =/2(^, y) be two functions of the three variables
a/*, 2/, 0, and these variables be selected at random so that there exists
no correlation between #,?/, y,z, or z,x, there will still be found to
* ' Economic Journal,' Dec., 1895, and Dec., 1896, " On the Correlation of Total
Pauperism with Proportion of Out-relief."
490 Prof. Karl Pearson.
exist correlation between u and vt Thus a real danger arises when a
statistical biologist attributes the correlation between two functions
like u and v to organic relationship. The particular case that is
likely to occur is when u and v are indices with the same denominator
for the correlation of indices seems at first sight a very plausible
measure of organic correlation.
The difficulty and danger which arise from the use of indices was
brought home to me recently in an endeavour to deal with a consider-
able series of personal equation data. In this case it was convenient
to divide the errors made by three observers in estimating a variable
quantity by the actual value of the quantity. As a result there
appeared a high degree of correlation between three series of abso-
lutely independent judgments. It was some time before I realised
that this correlation had nothing to do with the manner of judging,
bat was a special case of the above principle due to the use of indices.
A further illustration is of the following kind. Select three num-
bers within certain ranges at random, say #, y, z, these will be pair
and pair uncorrelated. Form the proper fractions xfy and z\y for
each triplet, and correlation will be found between these indices.
The application of this idea to biology seems of considerable
importance. For example, a quantity of bones are taken from an
088uariumt and are put together in groups, which are asserted to be
those of individual skeletons. To test this a biologist takes the
triplet femur, tibia, humerus, and seeks the correlation between the
indices femur / humerus and tibia / humerus. He might reasonably
conclude that this correlation marked organic relationship, and
believe that the bones had really been put together substantially in
their individual grouping. As a matter of fact, since the coefficients
of variation for femur, tibia, and humerus are approximately equal,
there would be, as we shall see later, a correlation of about 0'4 to
0'5 between these indices had the bones been sorted absolutely at
random. I term this a spurious organic correlation, or simply a
spurious correlation. I understand by this phrase the amount of
correlation which would still exist between the indices, were the
absolute lengths on which they depend distributed at random.
It has hitherto been usual to measure the organic correlation of the
organs of shrimps, prawns, crabs, Ac., by the correlation of indices in
which the denominator represents the total body length or total cara-
pace length. Now suppose a table formed of the absolute lengths
and the indices of, say, some thousand individuals. Let an " imp "
(allied to the Maxwellian demon) redistribute the indices at random,
they would then exhibit no correlation ; if the corresponding absolute
lengths followed along with the indices in the redistribution, they
also would exhibit no correlation, Now let us suppose the indices
not to have been calculated, but the imp to redistribute the abso-
Mathematical Contributions to the Theory of Evolution. 491
lute lengths j these would now exhibit no organic correlation, but
the indices calculated from this random distribution would have a
correlation nearly as high, if not in some cases higher than before.
The biologist would be not unlikely to argue that the index correla-
tion of the imp-assorted, but probably, from the vital standpoint,
impossible beings was " organic."
As a last illustration, suppose 1000' skeletons obtained by distribut-
ing component bones at random. Between none of their bones will
these individuals exhibit correlation. Wire the spurious skeletons
together and photograph them all, so that their stature in the photo-
graphs is the same ; the series of photographs, if measured, will show
correlation between their parts. It seems to me that the biologist
who reduces the parts of an animal to fractions of some one length
measured upon it is dealing with a series very much like these pho-
tographs. A part of the correlation he discovers between organs is
undoubtedly organic, but another part is solely due to the nature of
his arithmetic, and as a measure of organic relationship is spurious.
Returning to our problem of the randomly distributed bones, let
us suppose the indices f emur/humerus and tibia/humerus to have a
correlation of 0'45. Now suppose successively 1, 2, 3, 4, &c.,
per cent, of the bones are assorted in their true groupings, then
begins the true organic correlating of the bones. It starts from 0'45,
and will alter gradually until 100 per cent, of the bones are truly
grouped. The final value may be greater or less than 0'45, but it
would seem that 0*45 is a more correct point to measure the organic
correlation from than zero. At any rate it appears fairly certain
that if a biologist recognised that a perfectly random selection of
organs would still lead to a correlation of organ-indices, he would
be unlikely to accept index-correlation as a fair measure of the rela-
tive intensity of correlation between organs. I shall accordingly
define spurious organic correlation as the correlation which will be
found between indices, when the absolute values of the organs have
been selected purely at random. In estimating relative correlation
by the hitherto usual measurement of indices, it seems to me that a
statement of the amount of spurious correlation ought always to be
made.
(2; Proposition L — To find the mean of an index in terms of the
means, coefficients of variation, and coefficient of correlation of the two
absolute measurements.*
Let a?!, a^, a?3, a?4 be the absolute sizes of any four correlated organs ;
mlt Wz, Wa, m4 their mean values ; <?i, <r2, <r3, <r4 their standard deviations ;
* In all that follows, unless otherwise stated, the correlation may be of any kind
whatever, Le., the frequencies are not supposed to follow , the Gaussian or normal
law of error.
492 Prof. Karl Pearson.
VH Vi, ^3» v* their coefficients of variation, i.e., t^/m^ <r2/m2,
<r4/W4 respectively ; n2, r23, r34, r41, r24, r13, the six coefficients of corre-
lation ; EX, e2, 63, e4 the deviations of the four organs from, their means,
i.e, Xi = «!•! + €!, ic2 = ^2 + e2) #3 = w3+c3, 0*4 = m4-f e4; ?'13 the mean
value of the index a?i/ajs, and ^24 the mean value of #2/#4 ; 2i, 22 the
standard deviations of the indices x:/xs and #2/#4 respectively ; and n
the total number of groups of organs.
We shall suppose the ratios of the deviations to the mean absolute
values of the organs are so small that their cubes may be neglected.
Then
w3
= S(Cl) 8(63) S(6lC3)
if we neglect quantities of the third order in e/wi. But S(ex) =
S(e3) = 0, S(e1e3) = nrwtriff^ and S(e32) = na^.
Hence: »„ = ^(l + ^-r,^^) (i).
Similarly ^ = 2* (i+^-ww.) . . («)•
Thus we see that the mean of an index is not the ratio of the means
of the corresponding absolute measurements, but differs by a quan-
tity depending on the correlation and variation coefficients of the
absolute measurements.
(3) Proposition II. — To find the standard deviation of an index in
terms of the coefficients of variation, and coefficient of correlation of
the two absolute meastirements.
= ^ { S /^-^+ square terms)2 V
ma2 I \m! m3 / J
if we neglect cubic terms.
.-. 218 = il^(vl*+vj-2rl3vlv3). .......... (iii).
Mathematical Contributions to the Theory of Evolution. 493
(4) Proposition HI.— To find the coefficient of correlation of two indices
in terms^ of the coefficients of correlation of the four absolute measurements
and their coefficients of variation.
Let ajj/afc and x^x^ be the two indices.
X l+.-_
ra2 m4
m3
if we neglect terms of the cubic order.
(5) Thus we have expressed p in terms of the four coefficients of
correlation and the four coefficients of variation of the absolute
measurements which form the indices.
We may draw the following conclusions :
(i.) The correlation between two indices will always vanish when
the four absolute measurements forming the indices are quite uncor-
related,
(ii.) If two of the organs are perfectly correlated, let us say made
identical : for example, the third and fourth, so that r& =. 1, and v3 =
1-4, we find
p == — / ~^ — — — / - __ ___ — — ....... (v).
v Vi -f v$ —
This is the coefficient of correlation between two indices with the
same denominator (#i/#3 and #2/#3).
The value of p in (v) does not vanish if the remaining organs be
quite uncorrelated, i.e., r12 = rJ3 = rm = 0. In this case
This is the measure of the spurious correlation. For the special
494 Prof. Karl Pearson.
case in which the coefficients of variation are all the same, p0 = 0'5.
When the absolute sizes of organs are very feebly correlated, then
in most cases there will be a considerable correlation of indices.
Example (a). Suppose three organs, x\, #2, and x3 to have sensibly
equal coefficients of variation, and that the correlation of x\ and Xz =
rJ2 = r and of #1 and XA, as well as of x2 and x3 = r.
Then:
= O'5 + O'o
l-r1
This formula illustrates well in a specially simple case how the
correlation in the indices diverges from the spurious value 0*5, as we
alter r and r' from zero, i.e., as we introduce organic correlation.
According as r, the correlation of the numerators, is greater or less
than r', the correlation of the numerator with the denominator, the
actual index correlation can be greater or less than the spurious
value.
Example (6). If e\, z2 be the indices, then in the case of normal
correlation the contour lines of the correlation surface for the indices
are given by
= constant-
where 2j, Sa, and p are given by (iii) and (iv) above.
The contour lines of a surface of spurious index correlation are
given by
= constant,
while the uncorrelated distribution of the numerators a?t and xz is
given by the contours,
x\l<r\+x*l<r% = constant.
We are thus able to mark the growth of the spurious correlation
as we increase vz from zero ; we see the axes of the ellipses diminishing
and their directions beginning to rotate.
Example (c). To find the spurious correlation between the two chief
cephalic indices.
I have calculated the following results from the measurements
made on 100 " Altbayerisch " -$ skulls, by Professor J. E/anke. See
his ' Anthropologie der Bayern,' Bd. i, Kapifcel v, S. 194.
Mathematical Contributions to the Theory of Evolution. 495
Breadth of sknll :* ^ = 150-47, al = 5'8488, • t\ = '3-8871.
Height of skull : m2 = 133'78, a* = 4'6761, vz = 3'4954.
Length of skull ; ra3 = 180'58, <r3 =: 5'8441, v3 = 3'2363.
Cephalic index, B/L : ia — 83'41, 213 = 3'5794, Y13 =. 4'2913.
Cephalic index, H/L : i^ = 74;23, 223 = 3'6305, V23 = 4-8909.
Cephalic index, H/B : ^ = 89-12, 221 = 4-1752, V21 = 4'6849,
The coefficients of correlation may at once be deduced :
Breadth and length ; r13 = (v^+v^— V132)/(2*?2t;3) = 0'2849.
Height and length : r23 = (t>22 + v32— V232)/(2v2v3) = —0'0543.
Height and breadth ; r21 = (y + v?— V212)/(2i71v2) = 0'1243, .
This is the first table, so far as I am aware, that has been published
of the variation and correlation of the three chief cephalic lengths.f
It shows us that there is not at all a close correlation between these
chief dimensions of the skull, and that a small compensating factor
for size is to be sought in the correlation oE height and length, i.e.,
while a broad skull is probably a long skull and also a high skull, a
high skull will probably be a short skull, and a low skull a long skull.
Without substituting the values of v1} v2, t'3, ri2, ?'i3, r23 in
(v), we can find />, or the correlation between breadth/length and
height/length indices from ;
P = (V132-hV232-Y122)/(2Y13V23).
This follows at once from the general theorem given in my memoir
on " Regression, Panmixia, and Heredity," ' Phil. Trans./ vol. 187,
A, p. 279, or by substitution of the above values of rt2, ri3, r& in (v),
we find : ;
P == G'4857,
If we calculate from (vi) the correlation between the same cephalic
indices on the hypothesis that their heights, breadths and lengths
are distributed at random, i.e., that our "imp "-has constructed a
number of arbitrary and spurious skulls from Professor Ranke's
measurements, we find :
PQ — 0-4008.
It seems to me that a quite erroneous impression would be formed
of the organic correlation of the human skull, did we judge it by the
magnitude of the correlation coefficient (O4857) for the two chief
* All the absolute measures given are in millimetres, and the coefficients of
variation are 'percentage variations, i.e., they must be divided by 100 before being
used in formulae (i), (ii), and (iii).
f I hope later to treat correlation in man with reference to race, sex, and
organ, as I have treated variation.
496 Prof. Karl Pearson.
cephalic indices, for no less than 0'4008 of this would remain, if we
destroyed all organic relationship between the lengths on which these
indices are based.
Example (d). To find the spurious correlation lettueen the indices
femur jliumerus and femurj tibia.
The following results have been calculated* from measurements
made by Koganei on Aino skeletons. (See ' Mittheilungen aus der
medicinischenFacultat der K. J. Universitat, Tokio,' Bd. I. Tables.)
I have kept the sexes apart although there are but few of each.
3 Skeletons. Number = 40 to 44. Measurements in centimetres.
Femur, F : ml = 40'845, <TJ = 1'957, Vi = 4792.
Tibia, T : r^ = 31'740, <rz = T577, vz = 4'970.
Humerus, H : ma = 29'593, <r3 = 1*337, V3 = 4-517.
The following coefficients of coiTelation were calculated directly :
Femur and tibia : r12 ='0'8266.
Femur and humerus : r^ = 0'8585.
Tibia and humerus : r^ = 0'7447.
From these were deduced by the formulae of this paperf : —
Index, F/T : tw = 128'75, 212 = 3*7075, V18 = 2*8795.
Index, F/H : zls = 137'92, 213 = 3'4084, V13 = 2'4714.
Index, T/H: i23 = 107'02, 223 = 3-6675, Y23 = 3'4271.
Hence we find for the correlation of the indices F/H and T/H :
p = 0*5644.
But the spurious correlation, if the bones had been grouped at
random would have been
Q = 0-4557.
* I have to thank Miss Alice Lee for a considerable part of the arithmetic work
of this example.
f The values for the indices are not in absolute agreement with those to be
deduced from the lengths, for it was not always possible to use the same skeleton
for femur and humerus as for tibia and humerus, i.e., sometimes one or other bone
was missing. For the same reason, the constants for the absolute lengths do not
agree entirely with those given for Ainos in my paper on " Yariation in Man and
Woman" in 'The Chances of Death and other Studies in Evolution/ vol. 1,
p. 303), for the simple reason that I there used every available bone, and not every
available pair, as here.
Mathematical Contributions to the Theory of Evolution. 497
Tabulating the corresponding quantities for the other sex we
find
2 Skeletons. Number = 22 to 24. Measurements in centimetres.
Femur, F : m, = 38'075, a, = T494, Vl = 3'924.
Tibia, T : m2 = 29'800, <r2 = T576, vz — 5'289.
Humerus, H : m3 = 27'565, <r3 = 1-109, v5 = 4'022.
rn = 0-8457.
r13 = 0-8922.
r23 = 0-7277.
in = 127-90, 212 = 3'8937, V12 = 3'0444.
t13 = 138-37, 213 = 2-6930, V13 = T9462.
in = 108-36, 223 = 4-1022, V^ = 3'7857.
p = 0-6006.
p0 = 0-3904.
Femur and tibia :
Femur and humerns :
Tibia and humerus :
Index, F/T :
Index, F/H :
Index, T/H :
Hence we may conclude as follows :
(i) The absolute lengths of the long bones differ from those of the
skull in being very closely correlated.
(ii) The use of indices for the long bones would appear to mini-
mise, rather than, as in the case of the skull, to exaggerate this
correlation.
(iii) If we measure, however, organic correlation of the indices by
p—poi we shall find index correlation less than absolute length corre-
lation for both long bones and skull, and in both cases the former
comparatively small as compared with the latter.
(iv) The results for the 24 female skeletons, although based on
but few data, serve on the whole to confirm the male results.*
(6.) From the above examples it will be seen that the method,
which judges of the intensity of organic correlation by the reduction
of all absolute measures to indices, the denominators of which are
some one absolute measurement, is not free from obscurity ; for this
method would give the major portion of the observed index corre-
lation had the parts of the animal been thrown together entirely at
random, i.e., if there were no organic correlation at all. The follow-
ing additional remarks may be of interest. The results (iv) — (vi)
show us that the correlation coefficients of indices are functions, not
only of the correlation coefficients of absolute measurements, but also
of the coefficients of variation of the latter measurements. Hence,
* The fact that the male is more variable in height-sitting, in femur, and in
tibia tban the female, while she appears to be more vai-iable than he is in stature,
led me to prophesy, in my paper on " Variation in Man and Woman," that the
female would be found to be more closely correlated in the bones forming stature
than the male. This appears to be the case for the femur and tibia of Ainos.
VOL. LX. 2 P
498 Dr. F. Galton. Note to the Memoir by
unless the coefficients of variation be constant for local races, it is
impossible that the coefficients of correlation can be constant for
indices. In other words, the hypothesis of the constancy for local
races of correlation, and that of the constancy for local races of
variation, stand on exactly the same footing.
The conclusions of this paper although applied to organic correla-
tion are equally valid so far as concerns the use of indices in judging
the correlation of either physical or economic phenomena. It was,
indeed, a difficulty arising from my discussion of personal judgments
— a spurious correlation between the judgments of different observers
— which first drew my attention to the matter.
Note, January 13, 1897. — The result described by Professor
Pearson evidently affects the value of the correlation coefficients
determined by me in Grangon arid Carcinus (' Boy. Soc. Proc.,' vols.
51 and 54), because I have always expressed the size of the organs
measured in terms of body length.
In order to show the effect of this, I have lately performed, at
Professor Pearson's suggestion, the following experiment : It happens
that my measures of Plymouth shrimps are recorded in a book, in
the order in which they were measured, and therefore at random as
regards carapace length or other characters. I constructed from
these records 420 " spurious " shrimps, in the following way : the
total length of the first shrimp in the book was associated with the
carapace length of the tenth shrimp and the " post-spinous length "
of the twentieth, and so throughout. Evidently these three measures
were associated at random, and we might expect that these spurious
shrimps would show no organic correlation ; but when the cara-
pace lengths and " post-spinous lengths " of these spurious shrimps
were divided by the body length, and the correlation between the
resulting indices was determined, the value of r was found to be 0'38,
the value for real shrimps being 0*81, or the correlation due to the
use of indices forms 47 per cent, of the observed value.
W. F. B. WELDON.
" Note to the Memoir by Professor Karl Pearson, F.R.S., on
Spurious Correlation." By FRANCIS GALTON, F.R.S. Re-
ceived January 4, — Read February 18, 1897.
I send this note to serve as a kind of appendix to the memoir of
Professor K. Pearson, believing that it may be useful in enabling
others to realise the genesis of spurious correlation. It is important
though rather difficult to do so, because the results arrived at in the
memoir, which are of serious interest to practical statisticians, hav(
at first sight a somewhat paradoxical appearance.
Prof. Karl Pearson on Spurious Correlation. 499
The diagrams show how a table of frequency of the various com-
binations of two independent and normal variables may be changed
into one of A/C, B/C, where C is also an independent and normal
variable in respect to its intrinsic qualities, but subjected to the con-
dition that the same value of C is to be used as the divisor of both
members of the same couplet of A and B. In short, that the
couplets shall always be of the form A/C», B/CM, and never that of
A/a, B/cm.
For the sake of clearness, the simplest possible suppositions, that
are at the same time serviceable, will be made in regard to the
particular case illustrated by the diagrams, namely, that A, B, and C,
severally, are sharply divided into three, and only into three, eqnal
grades of magnitude, distinguished as AT, AIT, A1II; BI, BIT, Bill;
and CI, CII, CIII ; also that the frequency with which these three
grades occur is expressed by the three terms of the binomial
(l + l)3. Consequently there is one occurrence of I to two occur-
rences of II and to one occurrence of III. Roman and italic figures
are here used to keep the distinction clear between magnitudes and
frequencies. It will be easily gathered as we proceed, without the
'need of special explanation, that the smallness of the value of the
binomial index has no influence either on the general character of the
operation or on its general result.
The large figures in the outlined square, occupying the lower
right hand portion of fig. 1, show the distribution of frequency of the
various combinations of A and B. The scales running along the top
and down the left side of the figure, which are there assigned to the
values of A/C, B/C, apply to these entries also. The latter run in
the same way as those in Table I below, or when quadrupled, as they
will be for purposes immediately to be explained, as in Table II.
Table I. Table II.
121 484
242 8 16 8
121 484
Let us now follow the fortunes of one of the large figures in fig. 1,
say that which refers to A = I, B = III, of which the frequency is
only 1. When the latter is expanded into the three possible values
of the form A/C, B/C, caused by the three varieties of C, it yields
i case of frequency to (I/I, III/I), f case to (I/1I, .111/11), and
J case to (I/III, Ill/Ill), for entry at the intersections of the lines
, (I, III), (I/1I, HI/II), and (I/III, I) respectively.
But, in order to avoid the inconvenience of quarter values, it is
' better' to suppose the original figures in the fig. and in Table I above
to have been replaced by those in Table II ; then the original entry
2 P 2
500
Dr. F. Galton. Note to the Memoir by
Values
The diagonal includes 3 ''sets of entries,
Fiq.2.
Prof. Karl Pearson on Spurious Correlation.
501
from which we start will have become four, to be expanded into
three derivative entries, having respectively the frequencies 1, 2, and
1 ; these latter figures are entered in fig. 1 at the intersections of the
lines just named. Under this arrangement the large figure from
which we started, which had been changed from 1 to 4, again assumes
its original value of 1. It will easily be understood, that the posi-
tions of the three derivative entries necessarily lie in the same
straight line, and that this line necessarily runs towards the (0, 0)
corner of the figure. The same is true for every other set of deriva-
tive entries, with the result that whereas the original set of large
figures, referring to the combinations of A and B, are symmetrically
disposed on either side of the horizontal, of the vertical, and of the
diagonal lines passing through their common centre at (II, II), the
derivative values of A/0, B/C are disposed symmetrically only in
respect to the diagonal line that runs from the (0, 0) corner. Their
symmetry, in this sense, is well shown by the dotted connections
between the corresponding figures on either side of the diagonal.
Also, it will be seen that the diagonal passes through the regions of
greatest frequency. It follows that the diagonal in question repre-
sents the locus of average frequency. Now, along that diagonal,
each value of A/C is associated with identically the same value of
B/'C ; in other words, a correlation is found to have become estab-
lished between them, which is solely due to the fact that each
member in every couplet of A/C, B/C values is divided by the same
value of the variable C.
We will now submit the above process to the test of extreme
cases.
First, let the variability of A be so small that it may be treated as
a constant, and take it = 1.
Then the values of A/C and B/C, that are severally associated
with the three values of C, are as follows : —
Table III.
C.
A/C.
B/C.
Corresponding
frequencies.
I
I
I
II
III
121
II
I/II
I/H
I
III/II
121
III
I/III
I/III
II/III
I
121
These frequencies are laid down at their proper places in fig. 2,
where the three entries, corresponding to each successive value of
A/C, run in vertical lines, but, on connecting the entries of maximum
502 Prof. W. J. Sollas. Report to the Committee appointed
frequency it is seen that they coincide with the diagonal from the
0/0 corner; also that the entries of minimum frequency are dis-
posed symmetrically on either side of that diagonal and converge
towards the same corner. Consequently, the existence of spurious
correlation is manifest here. If B be the constant, and A and C the
variables, the general results will of course be the same.
Secondly, let both A and B be constant and equal to I, and C the
only variable ; then there are only three possible combinations of A/C
and B/C. In one of them both values are equal to I, in another
to I/II, and in the third to I/III, all of which lie along the diagonal
from (0, 0), and thus testify to intimate correlation.
Lastly, let C be the only constant and equal to 1. Then A/C, B/C,
become A and B, and the table of frequency of their various com-
binations is that shown in Table I and by the large figures in fig. 1,
whose symmetrical disposition in all directions proves that there is
no correlation.
" Report to the Committee of the Royal Society appointed to
Investigate the Structure of a Coral Eeef by Boring.''
By W. J. SOLLAS, D.Sc., F.R.S., Professor of Geology in
the University of Dublin. Received December 31, 1896,
—Read February 11, 1897.
Prefatory Note ly Professor T. G. Bonney, D.Sc., LL.D., F.R.S.,
Vice- Chairman of the Committee.
In presenting, as desired by the Committee, Professor Sollas's report
on the attempts to ascertain, by boring, the structure of the atoll
of Funafuti and on other investigations simultaneously undertaken,
I avail myself of the opportunity of expressing the gratitude which
is felt by its members to our friends in New South Wales, who have
given such real and substantial help, especially by the loan of
machinery and skilled workmen, in putting the project into execu-
tion ; and among them chiefly to Professor Anderson Stuart (who has
been practically another secretary in Australia), Professor Edgeworth
David, Mr. W. H. J. Slee (Chief Inspector of Mines), and Sir Saul
Samuel (the Agent- General of the Colony in England). I shall
venture also to acknowledge gratefully the services of Captain Field
and the officers of H.M.S. 4< Penguin," and the unstinted labour
which has been given by Mr. W. W. Watts, F.G.S., our Secretary in
London, in carrying out our plans. In conclusion, may I express,
speaking for myself, my earnest hope that another attempt will be
made to determine the true structure of an atoll. I think, however,
that our experience on this occasion shows that the attempt can be
to investigate the Structure of a -Coral Reef ly Boring. 503
much more easily made, and with a far greater probability of success,
if Australia instead of England be the base of operations, and I trust
that before long the colony of Sydney will initiate an expedition,
and we shall co-operate with them as cordially as they have done
with us.
Report by Professor Sollas, D.Sc., LL.D., F.R.S.
H.M.S. "Penguin" having come to anchor in the lagoon ot
Funafuti on the afternoon of Thursday, the 21st of May, Captain
Field at once landed with Lieutenant Dawson, Ayles (the foreman of
the boring party), and myself, and we proceeded to make arrangements
for our work on the island. A site for boring was chosen near the sandy
beach of the lagoon, conveniently situated for the landing of gear,
less than half a mile to the south and west of the village of Funafuti,
and near the village well, which supplies a small amount of brackish
but drinkable water. Tbe work of landing was commenced the next
morning, and completed by May 26. The erection of the boring
apparatus was at once taken in hand, and on June 2, twelve days
after our arrival on the island, all was in readiness for commencing
operations. On June 3 the 6-inch tubes were driven into the sand,
and by June 6 they had been advanced 30 feet ; the 5-inch pipes
were then entered and everything made ready for inserting the
diamond crown and commencing to drill on Monday, June 8. On
June 10 it was arranged that the work should proceed by shifts, so
that the drilling might be carried on continuously day and night.
During the first shift the crown had been advanced 20 feet, making
the total depth then attained 52 feet 9 inches ; during this shift
fragments of highly cavernous coral rock were brought up in the
core barrel from a depth of between 40 and 50 feet.
On June 11, a depth of 85 feet having been reached, it was found
necessary to ream the hole preparatory to lining, and by June 15 the
necessary reaming and lining had been completed. Up to this, although
we had been somewhat disappointed at our slow rate of progress,
occasioned partly by the unfavourable nature of the ground and
partly by the frequent failure of our machinery, we had anticipated
nothing worse than the possibility of finding our allotted time
exhausted before we had reached a depth of 1000 feet ; bat now, on
setting the crown to work, it very soon ceased to advance, and Ayles
shortly afterwards came to me to announce that, in his opinion, the
boring was a failure. Nevertheless, some further progess was sub-
sequently made, and on Tuesday, June 16, a depth of 105 feet was
attained. It then became once more necessary to ream and line the
hole. Attempts to ream were continued all through Wednesday and
Thursday but without success, sand poured into the hole and the
reamer could not be driven through it. Efforts were made to remove
504 Prof. W. J. Sollas. Report to the Committee appointed
the sand by a sand-pnmp, but proved unavailing, the sand flowing in
faster than it could be pumped out. Ayles assured me that it was
impossible to descend another foot, and that he considered further
labour as time and money thrown away. We decided therefore to
abandon this borehole, and to recommence operations 011 another site,
if possible in solid rock.
The structure of the ground passed through in the abandoned
borehole was as follows : —
< 2 ft. 9 in.
65 f£.
/05ft.
Sand wM some com/ b/ocks.
Coral reefs arid blocks with
seme sand.
Sand w/£h some cora,/ blocks.
Although I knew of many places where solid rock forms the
surface of the ground, it was very difficult to find one to which we
could transport our machinery, the difficulties of landing on a rocky
shore rendered several promising spots inaccessible by sea, while
the absence of wheeled vehicles or even wheels, and the nature of the
ground, seemed to put transportation by land out of the question.
At last, however, Mr. Hedley pointed out to me a portage called
Luamanif, and used by the natives for dragging their canoes
from the lagoon to the seaward side of the island, which at this
place is very narrow, about 70 yards across. As this seemed a
good landing-place, I submitted it to the consideration of Captain
Jb'ield, who, after a personal examination, agreed that we might
safely make use of it, Ayles and his party were then set to
to investigate the Structure of a Coral Reef by Boring. 505
work to sink trial pits on the line of tlie portage, one of these,
situated 70 feet from the high-water mark on the seaward face of
the reef, was sunk 12 feet through sand and blocks of coral, when
operations were brought a close owing to the influx of sea- water at
high tides. Two other pits were then commenced nearer the sea and
a little to one side (north) of the portage, at the margin of the solid
platform of rock, which extends down to the growing edge of the
reef and which is covered by the sea at high- water. These passed
through sand and fragments of coral. In the most northern of the
two pits the sand was somewhat consolidated, and so, proceeding a
few yards further north, as far in that direction as it would have
been possible to transport our machinery, we opened another pit,
which was sunk for a depth of 11 feet through fragments of coral,
crystalline coral limestone, and partly consolidated sand. The
bottom of the pit was 2 feet below the seaward margin of the reef,
and as we were not inconvenienced by an influx of sea-water and
Ayles was of opinion that the rock would " stand," we decided to
make our new venture at this spot. Taking into consideration the
difficulties of transporting our apparatus, I do not think a more
favourable locality could have been chosen ; it was close to the very
edge of the rocky platform, which is so hard that Darwin, speaking
of a similar platform in the case of another reef, says " I could with
difficulty and only by the aid of a chisel procure chips of rock from
its surface ;" and as near the sea as it was prudent or even possible
to go. Indeed, we had at first some doubt as to whether our pump-
ing pipes would ': live " in the surf of the ocean margin, and feared
that the high- water spring tides might inundate the shaft ; our fears
in these respects, however, proved to be groundless.
Tri&lpf /.
Captain Field and myself were impressed with the need of addi-
tional boring apparatus, and he proposed that Ayles should go to
Sydney to see if it could be procured. I gave much anxious con-
sideration to this project, and discussed it with my colleagues,
Messrs. Hedley and Gardiner, and with Ayles. The information I
received from Ayles was not encouraging. He stated that we
should require a complete equipment of lining tubes from 10 inches
down to 21 inches in diameter, that 10-inch tubes were not to be had
in Sydney, and that even if we succeeded in obtaining all the
506 Prof. W. J. Sollas. Report to the Committee appointed
appliances we required, the success of the boring would even then by
no means be assured.
For a doubtful result I did not feel justified in incurring the certain
increase in our expenditure which a journey to Sydney would have
involved; the question of time had also to be considered, for had Ayles
gone to Sydney we should on his return have been commencing our
boring at or after the date the Committee had considered it would
have been completed. Finally, it appeared that the new locality we
had chosen for our work offered fair prospects of success.
The shaft already sunk to a depth of 11 feet was then timbered
with Pandanus logs, and arrangements made for carrying down a
hole by jumping with a 6-inch chisel. Ayles spoke of getting as far
as 50 feet by this means, and then lining the hole with 6-inch tubes,
but after sinking 4 feet he declared it impossible to proceed further
in this way, the chisel could not be made to continue sinking in a
straight line, the labour was too exhausting, a/nd progress very slow.
It was decided, therefore, to begin boring, Ayles being very hope-
ful, as the hole " stood " well. On Thursday, June 25, we accord-
ingly made arrangements to shift our boring gear to the new site,
and by Saturday, June 27, this work was completed, chiefly by native
labour, and at a cost of about £10. The boilers were rolled along
the beach, the rest of the machinery taken by water, and all subse-
quently dragged, rolled, or carried across the portage. Lieutenant
Waugh lent us valuable assistance, during the absence of the " Pen-
guin," in this work.
Boring was commenced on Friday, July 3, and by 5 o'clock we had
sunk another 4 feet ; progress then became rapid, and on Saturday
evening, when work was knocked off, we had descended in all
46 feet. Very little " core " was obtained, however, and at times the
boring bit met with very little opposition as it advanced, seemingly
passing through a vacant space. Since the water pumped into the
hole no longer flowed out above, but found its way out by some com-
munication with the sea below, it was impossible to determine
whether or not some sand might have been present. It was clear,
however, that the coral rock through which the " bit " advanced was
highly cavernous.
On Monday the hole became filled with fallen fragments and some
sand, it was evident, therefore, that the sides would not hold, and so
recourse was had to lining ; by Thursday, July 9, the hole had been
reamed and lined down to 45 feet, and the work of boring was re-
sumed. On pumping, we had the satisfaction of seeing the water
flowing out of the top of the hole, but our joy was short-lived, for, on
Monday, June 13, the water was again lost. On Tuesday, July 14, we
had reached 65 feet, passing for the last 20 feet through sand and coral.
Subsequently we attained a depth of 72 feet, and could then proceed
to investigate the Structure of a Coral Reef by Boring. 507
no further. We worked all Thursday and Friday with the sand
pump, but with no success ; the bottom of the hole was surrounded
by quicksand containing boulders of coral, and as fast as the sand
was got out, so fast it flowed in and faster. The water pumped
down disappeared through the sand, boring and a fortiori reaming
was impossible, and the tubes could not be driven owing to the inter-
spersed boulders. Had the tubes been provided with steel driving
ends we might have forced them down ; as it was, the effect of driv-
ing them was simply to curl in the lower end. Had we been pro-
vided with 4-inch tubes we could have made a fresh start, and might
have descended another 30 or 40 feet, but even then ultimate success
would not have been ensured, for the chance of meeting again and
again with intermixed sand and coral remained always open, and
every such encounter would have required lining tubes of diminished
calibre.
Baffled in all our endeavours, and no other part of the island offer-
ing more hopeful prospects of success, we had no alternative but to
abandon the undertaking, and on July 30 we were taken from the
island in the " Penguin," and returned to Fiji. On landing there we
had the mortification to learn that additional apparatus was then on
the way to Funafuti, our friends in Sydney having with great
generosity at once despatched machinery for driving in sand on re-
ceipt of a letter I had sent informing them of the failure of our first
borehole. We had had no reason to expect such spontaneous assist-
ance, and even had we been fortunate enough to have remained 011
the island till the machinery arrived, we should probably not have
accomplished the object we had in view, though we might possibly
have carried the borehole down to a depth of about 400 feet.
A very free communication must have existed between the bore-
hole and the sea, for whenever a big roller broke upon the reef the
rods lifted, and after the lining had been withdrawn, water spurted
out of the borehole with the fall of every wave. The open nature of
the reef is further indicated by the fact that the sea water rises with
every tide to fill certain depressions, which occur in many places in
the middle of the island; as the tide ebbs this water flows away down
fissures, often so rapidly as to form little whirlpools.
Wherever I have seen the reef growing it has always presented
itself as clumps or islets of coral and other organisms with inter-
spersed patches of sand, and the borings would seem to indicate that
it maintains this character for a very considerable depth and possibly
throughout. The structure of the reef appears indeed to be that of a
coarse " sponge " of coral with wide interstices, which may be either
empty or filled with sand.
As regards the nature of this " sand," it is important to observe
that it does not consist of coral debris; this material and fragments
508 Prof. W. J. Sollas. Report to the Committee appointed
of shells forming but an insignificant part of it ; calcareous algos are
more abundant, but its chief constituents are large foraminifera,
which seem to belong chiefly to two genera (Orbitolites and Tinoporus).
It covers a considerable area of the islands, and has accumulated dur-
ing the memory of the inhabitants to such an extent as to silt up
certain parts of the lagoon. This and the abundant growth of corals
and calcareous algse, such as Halimeda, lead to the belief that the
lagoon is slowly filling up.
A suggestion has recently been made that more light is likely to
be thrown on the history of atolls by a study of ancient limestones
in the British Isles than by boring in existing reefs. The first essen-
tial, however, for such a study would appear to be a knowledge of
the structure of living atolls, for, without this, the identification of
others forming a part of the earth's crust, might remain more or less
a matter for conjecture. So far as the structure of Funafuti has
been proved by borings, it is scarcely what a field geologist might
have anticipated, and if deposits of a similar nature and origin
should have been encountered in, say, the mountain limestone, it is
doubtful whether, previous to the borings in Funafuti, their inter-
pretation would have been easily reached.
While the boring has proved a failure, the other objects of the ex-
pedition have been attained with complete success. Messrs. Hedley
and Gardiner have made a thorough investigation of the fauna and
flora, both land and marine. Dr. Collingvvood has obtained a good
deal of information of ethnological interest, and we all have brought
home a fairly complete collection of native implements and manufac-
tures. A daily record was kept of maximum and minimum tempera-
ture, and of the readings of the dry and wet bulb thermometers.
The most important contribution, however, and one that I think
must, in certain details, greatly modify our views as to the nature of
coral reefs, is afforded by the investigations of Captain Field. Never
before have soundings, both within and without an atoll, been so
closely and systematically made, and the results seem to me commen-
surate with the care and pains that have been taken to secure them.
Four series of soundings, " Sections " as they are termed on board
the " Penguin," have been run from the seaward face of the reef out-
wards. How close together the soundings were made is shown in
the following table which Captain Field has kindly permitted me to
copy from his order book : —
Depth 0 — 40 fathoms every 10 yards.
40— 70 „. 20 „
70—100 „ 30 „
„ 100—150 ,; 40 „
150—200 50
to investigate the Structure of a Coral Reef by Boring. 509
Depth 200—300 fathoms every 60 yards.
„ 300—400 „ 70 „
„ 400—500 ., 80 ;,
„ 500—600 „ 90 „
., 600—700 „ 100 „
700—800 200
The profiles obtained by the four series are closely similar, and, as
regards one important feature, almost identical. This is the sudden
change in slope that occurs at or about 140 fathoms. Speaking
generally, one may describe Funafuti as the summit of a submerged
conical mountain, the base of which, at a depth of 2,000 fathoms, is
a regular ellipse, 30 miles long by 28 miles broad. It rises with a
very gentle slope, which gradually grows steeper as it ascends, till
from 400 to 140 fathoms it has an angle of 30° ; at 140 fathoms an
Section D.
;,<too
200
to
£0
40
60
60
'00
zoo
5OO
575?
too
Two profiles of the ocean face of Funafuti. Vertical and horizontal scales
identical. Figures on the vertical co-ordinate refer to fathoms, on the horizontal
to yards.
The curve on the left is supposed to commence 200 yards to the left of the zero
point.
abrupt change occurs, and the slope becomes precipitous, making an
angle of from 75° to 80° for the greater part of its course, till it
passes into the shallow flats of the growing reef. It is difficult to
resist the impression that it is the upper 140 fathoms (840 feet)
which represents the true coral reef. A convex curvature of the
profile between 166 and 261 fathoms is probably a talus, produced by
an accumulation of coral debris.
510 Prof. W. J. Sollas. Report to the Committee appointed
The conical mountain below the 140 fathoms line, with its parabolic
slope, is suggestively similar to a volcano; but, if so, its crater must
have been immense, 10 miles across at least. A volcano, 12,000 feet
in height, with a cra.ter 10 miles in diameter, is, however, not
an unknown phenomenon ; within the limits of the Pacific we may
cite Haleakala, in Maui, Sandwich Islands, as closely comparable.
A part of my work while on the island was the construction of a
geological sketch map, part of which is shown below ; its interest
chiefly centres in a broad expanse near the Mission Station, where the
two narrow limbs of the island meet, or, if it be preferred, whence
Corner of Funafuti, showing Mangrove Swamp and Heliopora Keef.
A.S.C. Mangrove swamp,
reef.
sot/dated cora/ breccia
N, I/ ~< ming parC of the f/oor
of the -swamo.
C3o0oi C//nker f/e/d of
o o
cora/ fragments.
to investigate the Structure of a Coral Reef by Boring. .511
they extend. Towards the seaward side this broad corner is occupied
by a mangrove swamp, the floor of which is formed by a dead coral
reef, constituted almost wholly of two species, one a massive Porites,
and the other HeUopora ccerulea. For a great part of the day this
floor lies bare and dry, the frayed ends of the Heliopora standing like
broken reeds, 6 inches above its surface, and the great clumps of
Porites forming a series of stepping stones of equal height. Neither
of these corals stands long exposure to the air ; on Funafuti they
require constant submergence, and we are thus led to regard their
upper surface as marking what was at one time the level of low tide
in the swamp; but since the present level of low tide is below the
level thus indicated, some change must have occurred in the level of
low tides. Not necessarily an elevation of the reef : Darwin has admi-
rably discussed this explanation, and it is quite conceivable that some
change in local conditions, such as the exclusion of the sea by the
growth of the hurricane beach, may have produced a local alteration
in the height of the tides. The swamp communicates with the sea
by pits in its floor, which enter subterranean channels running sea-
wards. These passages are so narrow that the tide rises and falls
in the swamp much more slowly than in the open sea. To determine
whether any change of level has taken place, it thus becomes neces-
sary to compare the highest and lowest water level of the swamp
with that of the sea or of the lagoon. I accordingly levelled across
the island from the lagoon to the sea, crossing the swamp on the
way, and found that the high-water level at spring tides is 1 foot
10 inches below high water (spring tides) of the lagoon, so that
given free access of the sea, the Heliopora reef would be covered
1 foot 10 inches deeper than at present, but it is now submerged from
10 inches to 2 feet 2 inches at high-water springs, and would accord-
ingly be submerged from 2 feet 8 inches to 4 feet, with free access of
the sea, The range of spring tides is at least 6 feet, as I learn from
Lieutenant Dawson, but I am not quite sure that an extreme range
of 9 feet 8 inches has not been observed. Taking, however, the
smaller number, it becomes clear that for a considerable part
ot' the day, the reef woulcb be exposed to the air. It is not likely
that under these conditions the corals would continue to live, and
I think, therefore, that the reef must have undergone some slight
elevation, to the amount, perhaps, of 4 feet. This conclusion is in
accordance with Dana's view, and is supported by observations on
some other features of the island, such, for example, as the occur-
rence of an interrupted line of low cliffs, sometimes passing into a
series of pinnacles, generally about 4 feet in height, as measured from
low water level. In the annexed section the cliffs are farther from
the land than is usually the case. These cliffs consist of a consoli-
dated breccia of coral fragments, and are now in process of denuda-
512 Prof. W. J. Sollas. Report to Coral Reef Committee.
tion, as is the coral platform which, extends from
them, up to and under the hurricane beach. This
breccia was probably formed and cemented toge-
ther when the reef stood at least 4 feet lower than
at present, and was produced by the breakers
driving fragments of corals from the seaward edge
of the reef into the lagoon, as they are now doing
over the isthmuses, submerged at high tide, which
connect the several islets of the atoll together.
If it should prove true, as I do not doubt, that
one of the latest episodes in the history of the reef
has been an elevation of, say, 4 feet, then in the
immediately antecedent stage, the reef must have
been awash, or, perhaps, wholly submerged, and
the present terrestrial fauna and flora must have
reached it subsequent to its elevation, as sea drift,
or have been introduced by human agency.
In conclusion, I would add that to myself the
soundings obtained by Captain Field appear to
support Darwin's theory of coral atolls ; there
remains, however, one very important branch of
the subject which stands in need of renewed in-
vestigation, and this is the bathymetiical limit to
coral life.
Not till I had obtained a close acquaintance with
the difficulties of dredging on the steep sides of an
atoll did I recognise on how frail a basis our
accepted conclusions rest. It is a task difficult
enough to get up corals from the lagoon in com-
paratively shallow water ; from the sides of the
reef it is well nigh impossible. To obtain dead
corals from great depths proves little ; living corals
are generally found with dead associates, and the
latter are the more readily detached and brought
to the surface. *
The weight of the evidence we already possess
is admittedly in favour of a comparatively shallow
bathy metrical limit, but much remains to be done
before we can speak of any limit as definitely
ascertained.
Prof. U. Lodge. Radiation Frequency. 513
" The Influence of a Magnetic Field on Radiation Frequency."
Communication from Professor OLIVER LODGE, F.R.S.
Received and read February 11, 1897.
I ask permission to bring before the notice of the Fellows a
notable discovery recently made at Leyden by Dr. P. Zeeman, who is
now elected Professor of Physics in the University of Amsterdam.
To put myself in order, I will state that I have set up apparatus
suitable for showing the effect, and have verified its primary feature,
viz., that both lines in the ordinary spectrum of sodium are broad-
ened when a magnetic field is concentrated upon the flame emitting
the light.
Zeeman has observed it likewise with lithium, and with absorption
as well as with emission spectra ; taking precautions against decep-
tion by spurious effects due to changes of density or of temperature.
It is thus probably not a chemical fact, dependent on the nature of a
substance, but a physical fact, dependent on the nature of radiation
and absorption, i.e., a fact connected with the interchange of energy
between ether and matter.
Faraday appears to have looked for some such phenomenon in the
course of his latest magneto-optic researches in 1862, but he had not
a Rowland concave grating at his disposal, and the effect is small.
I saw it with a 1-inch flat reflection grating containing 14,600
lines, and with an oxy-coal gas flame playing on pipe clay supporting
carbonate of soda between pointed poles. I tried to see it by
widening the slit till the D lines almost encroached on each other ;
thinking thereby to see the residual dark space obliterated by the
magnetic action. A luminous haze seemed to spread over the dark
chink when the magnet was excited, but the chink itself did not dis-
appear ; and the effect is more conspicuous and easier to observe
when the narrowest slit possible is used, and when a micrometer
spider-line is set down the middle of one of the D lines, of the second
order spectrum, well defined in a field of considerable magnifying
power.
The broadening is then unmistakable, and is symmetrical on each
side; but I judge that the edges are not so bright as the central
portion. The line appears brightened as well as broadened, i.e., the
previous borders of the line are brightened, and there are also
gradated extensions. If the focussing is sharp enough to show a
narrow, dark reversal line down the middle of either sodium line, that
dark line completely disappears when the magnet is excited.
With the help of Professor H. A. Lorentz, the discoverer has
initiated a simple theory of the effect, by considering the effect of
VOL. LX. 2 Q
514 Dr. J. Larmor. The Influence of a
magnetic force on the motions of oscillating and revolving electrified
particles possessing inertia (ions or electrons) in a magnetic field ;
and it is thus shown that the broadened edges of the line ought, on
Lorentz's view, to be emitting polarised light, viz., plane polarised in
directions normal to the lines of force, and circularly polarised in a
direction along those lines.
This prediction has been experimentally verified by Zeeman, and
has likewise been confirmed by myself. The flame being looked at
from a direction perpendicular to the magnetic field, the light which
will be dispersed by the grating to form the extended borders of a
line is plane polarised, with its electric oscillations normal to the
field's lines of force.
I hope to have the pleasure of communicating an English version
of Professor Zeeman's complete paper to the March number of the
* Philosophical Magazine.'
u The Influence of a Magnetic Field on Radiation Frequency."
Communication from Dr. J. LARMOR, F.R.8. Received
and read February 11, 1897.
In the course of the development of a dynamical hypothesis* I
have been led to express the interaction between matter and ether
as wholly arising from the permanent electrons associated with the
matter ; and reference was made to von Helmholtz (1893) and Lorentz
(1895) as having followed up similar views. A footnote in Dr.
Zeeman's paper has drawn my attention to an earlier memoir of
Lorentz (1892), in which it was definitely laid down that the electric
and optical influences of matter must be formulated by a modified
Weberian theory, in which the moving electrons affect each other,
not directly by action at a distance but mediately by transmission
across the ether in accordance with the Faraday-Maxwell scheme of
electric relations. The development of a physical scheme in which
such action can be pictured as possible and real, not merely taken as
an unavoidable assumption which must be accepted in spite of the
paralogisms which it apparently involves,t was a main topic in the
papers above mentioned.
The experiments of Dr. Zeeman verify deductions drawn by
Lorentz from this view. It might, however, be argued that inasmuch
as a magnetic field alters the index of refraction of circularly pola-
rised light, which depends on the free periods of the material
molecules, it must therefore, quite independently of special theory,
* < Phil. Trans./ 1894, A, pp. 719—822; 1895, A, pp. 695—743.
t H. A. Lorentz, " La Theorie Electromagnetique cle Maxwell, efc ses Applica-
tions aux Corps Mouvants," 'Archives Neerlandaises,' 1892. Cf. especially § 91.
Magnetic Field on Radiation Frequency. 515
alter the free periods of the spectral lines of the substance. Bat the
actual phenomena do not seem to be thus reciprocal. On the
electric theory of light it is only the dispersion in material media that
arises from direct influence of the free molecular periods, the main
refraction arises from the static dielectric coefficient of fche material.
which is not connected with the periods of molecules.* From the
phenomena of magneto-optic reflexion it may be shown that, on the
hypothesis that the Faraday effect is due to regular accumulated
influences of the individual molecules, it must be involved in the
relation between the electric force (PQK) and the electric polarisa-
tion of the material (/V V), of type
.^,
4?r dt dt
where (ciC3c3) is proportional to the impressed magnetic field. This
relation, interpreted in the view that the electric character of a
molecule is determined by the orbits of its electrons, simply means
that the capacity of electric polarisation of the molecule depends on
its orientation with regard to the imposed magnetic field, that, in fact,
the static value of K, depending on the molecular configurations jnst
as much as do the free periods, is altered by the magnetic field. This
relation agrees with the main feature of rotatory dispersion, namely,
that it roughly follows the law of the inverse square of the wave-
length. The specific influence of the molecular free periods, that is,
of the ordinary dispersion of the material, on the Faraday effect, is
presumably a secondary one ; though it, too, follows the same law
for different wave-lengths, in the case of substances for which Cauchy's
dispersion formula holds good. It is this latter part of the Faraday
effect that is reciprocal to Dr. Zeeman's phenomenon.
The question is fundamental how far we can proceed in physical
theory on the basis that the material molecule is made up of revolv-
ing electrons and of nothing else. Certain negative optical experi-
ments of Michelson almost require this view ; at any rate, they have
not been otherwise explained. It may be shown after the manner of
1 Phil. Trans.,' 1894, A, p. 813 (and Dr. Zeeman's calculation, in fact,
forms a sufficient indication of the order of magnitude of the result),
that in an ideal simple molecule consisting of one positive and one
negative electron revolving round each other, the inertia of the
molecule would have to be considerably less than the chemical
masses of ordinary molecules, in order to lead to an influence on the
period, of the order observed by Dr. Zeeman. But then a line in the
spectrum may be expected to arise rather from one of the numerous
epicycles superposed on the main orbits of the various electrons ia
the molecule than from a main orbit itself.
* Loo. cit., ' Phil. Trans.,' 1894, A, p. 820 ; and 1895, A, p. 713.
OBITUARY NOTICES OF FELLOWS DECEASED.
HERMANN KOPP, who was elected a Foreign Member of the Royal
Society in 1888, and who died in Heidelberg on February 20,
1892, was born on October 30, 1817, at Hanau, where his father,
Johann Heinrich Kopp, practised with some distinction as a physi-
cian. The father occupied himself in his leisure with experimental
chemistry, and a few papers by him on mineral analysis and on
physiological chemical products are to be found in Leonhard's
' Taschenbuch ' and Gehlen's ' Journal/ The subject of this notice
received his school training at the gymnasium of his native town,
where he was well grounded in Latin and Greek. The facility
he thus acquired in reading classical literature never left him, and
proved of incalculable service to him in the preparation of his great
work on the history of chemistry. At eighteen he went to Heidel-
berg, where he studied chemistry under Leopold Gmelin and physics
under Wilhelm Muncke. At that time Heidelberg presented few
opportunities for acquiring a knowledge of practical chemistry.
Gmelin was Ordinary Professor of Medicine as well as of Chemistry,
and his chemical teaching was regarded as subordinate to that of
medicine. Kopp left Heidelberg for Marburg, where he graduated
in 1838, presenting to the Philosophical Faculty as his thesis an
essay entitled ' De oxydorum densitatis calculo reperiendss modo,' in
which we trace the germs of the experimental work by which he is
best known. From Marburg he passed on to Giessen, attracted
thiiher by the growing fame of the chemical laboratory which Liebig
had called into existence. Here he made, under Liebig's direction,
the only investigation in pure chemistry that he ever published, an
unimportant paper on the decomposition of mercaptan by nitric acid,
for the most part a repetition of the work of Lowig and Weidmann
on ethylsulphonic acid and its salts.
Kopp, however, elected to cast in his lot with that of Giessen, and
in 1841 he became Privat Docent in that University, lecturing on theo-
retical chemistry, crystallography, meteorology, and physical geo-
graphy. He now began, when barely twenty-four years of age, his
celebrated * History of Chemistry,' the work by which he is best known
to the literary world. In 1843 he became Extraordinary Professor,
and on the departure of Liebig to Munich in 1852 he and Heinrich
Will were made Ordinary Professors, and were placed in charge of
b
11
the Giessen laboratory. This position he resigned after the first
year, leaving Will the sole control of the laboratory. Kopp remained
at Giessen nearly a quarter of a century, and all his most im-
portant experimental work was done there. In 1863 he received a
call from Heidelberg, which he accepted, and here he stayed until
his death, occupying himself with lectures on the history of che-
mistry and on chemical crystallography. He was repeatedly solicited
to accept a position in one of the larger Universities, notably in
Leipsig and in Berlin, but all attempts to draw him from his dear
Ruperto- Carolina were fruitless. " Even Bunsen alone," he was
wont to say, " keeps me fast in Heidelberg."
Kopp's ' History of Chemistry ' is his greatest literary effort.
The first volume of it appeared in 1843, and the fourth and final
volume in 1847. By the publication of this classical work, Kopp,
when barely thirty years of age, suddenly found himself famous.
His life- long friend, von Hofmann, who was then at Giessen, has left
us the following account of the sensation which the work made on its
appearance : —
" With one accord his contemporaries recognised that here was a
production which, whether they regarded the thoroughness of re-
search that it displayed, or the manner in which the material
resulting from that research was sifted and arranged, was without a
parallel in the literature of any other country. And even to-day,
after the lapse of nearly half a century, there is no historical work on
chemistry that can be even remotely compared with it. Numbers of
books relating to the same subject, some of considerable merit, have
since been published in Germany and France, but it is not difficult to
perceive that they are all grounded on Kopp's great work."
For upwards of forty years Kopp had it in contemplation to bring
out a new edition, and much of the later historical work he published,
such as his * Beitrage zur Geschichte der Chemie,' which appeared
between 1869 and 1875, and the ' Entwicklung der Chemie in der
neueren Zeit,' printed under the auspices of the Historical Commis-
sion of the Bavarian Academy in 1873, together with the two
volumes on * Die Alchemie in alterer und neuerer Zeit,' grew out of the
materials he had gathered together. " But," again to quote Hofmann,
" the better is here the enemy of the good. Kopp postponed the ' ver-
mehrte und verbesserte Auflage ' year after year, in the hope of
being able to make a fuller study of certain special periods. Who-
ever is familiar with the mass of profoundly interesting matter he
had accumulated, or who has had the opportunity of seeing the
bulky note-books in which it was stored, must deeply lament that the
hand which could alone arrange these treasures is now stiffened in
death."
The literature of chemistry is further indebted to Kopp for the
Ill
part he played in the foundation and execution of the well-known
'Jahresbericht iiber die Fortschritte der Chemie und verwandter
Theile anderer Wissenschaften.' This great work was, in a sense,
the outcome and continuation of Berzelius' 'Yearbook.' On the
death of the Swedish chemist in 1848, the leaders of the Giessen
school of chemical thought determined to carry on his work of
registering the progress of chemistry, but on a somewhat different
plan. Berzelius at the time of his death was the greatest chemical
critic of the time, and wielded his authority with all the despotism of
an Oriental potentate, The 'Jahresbericht' of Liebig and Kopp
differed fundamentally both in plan and execution from its Swedish
prototype. It was to be a review of the year's progress, not only in
chemistry, but also in all those sciences which were associated with
chemistry, or were, in any definite sense, ancillary to it ; it was to be
done impartially, and with no special reference to any set of dogmas
or particular school of chemical thought. Practically the whole of
the more active members of the scientific side of the Philosophical
Faculty of the University were concerned in its production. To Kopp
fell the greater share of the arrangement, and of the general editorial
management ; in addition, he undertook the summaries relating to
Theoretical, Physical, and Inorganic Chemistry. To Buff and Zam-
miner was entrusted Pure Physics ; to Heinrich Will, Organic
Chemistry ; to Knapp, Technical Chemistry ; to Ettling, Mineralogy ;
and to Dieffenbach, Chemical Geology. The first volume appeared
towards the close of 1849, and consisted of a review of the work of
1847 and 1848. Liebig continued to be associated with Kopp as
editor for some years after his removal to Munich, but in 1857 his
place was taken by Will, who acted as co-editor until 1862, when
Kopp resigned his share in the responsible direction of the publica-
tion just prior to his removal to Heidelberg. No chemist active in
the prosecution of research needs to be reminded of the value of the
' Jahresbericht.' It has undoubtedly exercised a most beneficient
influence on the development of chemical science in Germany, and it
has been of the greatest service to those chemists in this country to
whom German is not an unknown tongue.
In 1851 Kopp joined Liebig and Wohler in the production of the
' Annalen der Chemie und Pharmacie,' and for many years he took
the responsible share in its management. He prepared the section
on " Theoretical Chemistry " in that well-known text-book, Graham-
Otto's ' Lehrbuch der Chemie ' and his ' Introduction to Crystallo-
graphy,' written specially for chemists, was long a standard work.
Kopp's scientific papers relating to his experimental and critical
labours appeared mainly in ' Poggendorff's Annalen,' and in the
' Annalen der Chemie und Pharmacie.' Two or three of his early
communications were printed in the * Philosophical Magazine,' and
IV
his elaborate memoir, " On the Specific Heat of Compound Sub-
stances," in which he sought to develop Neumann's law, was published
by the Royal Society. The * Uoyal Society Catalogue of Scientific
Papers ' gives the number of his papers as 65.
Kopp enjoys an almost unique position as an investigator. The
one consistent purpose of his work was to establish a connexion
between the physical and chemical nature of substances ; to prove, in
fact, that all physical constants are to be regarded as functions of the
chemical nature of molecules. It is not implied, of course, that the
conception of such an interdependence originated with him. As a
matter of fact, almost immediately after the publication of Dalton's
' New System of Chemical Philosophy,' in which the doctrine of
atoms was revived to account for the fundamental facts of chemical
union, the endeavour was made to connect the chemical attributes of
a substance with one of its best defined physical constants, viz., its
atomic mass. Prout's hypothesis is, in reality, the generalised
expression of such an attempt ; it is an adumbration of Mende-
leefFs great discovery of the Law of Periodicity. But it may
be justly claimed for Kopp that no one before him made any
systematic effort to connect such of the physical qualities of sub-
stances as admit of quantitative statement with the stoichiomefcrical
values of such bodies. The sporadic attempts made prior to 1840
were practically fruitless on account of the imperfect nature of the
physical data up to that time extant.
When Kopp began his inquiries, very few boiling points were
known, even approximately ; and he had, as a preliminary step, to
ascertain the conditions under which such observations must be made
in order that accurate and comparable results could be obtained.
The thermal expansions of barely half a dozen liquids had been
measured, and the very methods of making such measurements with
precision had to be worked out.
At the outset of his investigations, Kopp found the physical con-
stants with which he was more immediately concerned very much as
Berzelius found Dalfcon's values of^the relative weights of the atoms ;
at the close of his work they were hardly less accurately known than
were those stoichiometric numbers to the ascertainment of whicfli the
great Swedish chemist had dedicated his life.
Kopp's more important memoirs readily and naturally fall into
comparatively few groups, viz., (1) those concerning the relations
between the specific gravities of substances and their molecular
weights; (2) those treating of the relations between boiling point
and chemical composition ; and (3) the papers relating to the specific
heats of solids and liquids. As regards the other papers, only the
briefest notice is here possible. Much of this work was of a pioneer
character, and his conclusions have necessarily been modified by
subsequent research. His " law " of boiling points is no longer
regarded as an accurate expression of experimental facts, and his
deductions with respect to specific volumes have been largely affected
by subsequent work. It has been conclusively shown that molecular
volume is not a purely additive property. There is no longer room
for doubt that the molecular volumes of substances are affected by
far more conditions than Kopp was able to take cognisance of.
The value CH2 = 22 has no other significance than as expressing
the average increment in volume in successive members of a homo-
logous series. Indeed, as the physical data increase, it becomes
doubtful whether even this mean value is correct. Later observations
appear to show that the value augments as the series is ascended.
The relation C = 2H no longer applies to carbon compounds in
general. What is true of carbon and hydrogen is equally true of
oxygen, whether as carbonyl- or as hydroxyl-oxygen. No definite or
uniform values can be assigned to oxygen such that the molecular
volume of a liquid can be a priori determined. The values given by
Kopp are simply mean values, but the actual volumes are affected by
conditions of which, as yet, we have no very precise knowledge or any
certain means of measuring. The values for the other elements are,
of course, affected by these considerations. Thus the specific volume
of chlorine is obtained on the assumption that the values for carbon
and hydrogen are constant. All, then, tends to show that the molecular
volume is not the sum of constant atomic volumes.
Although Kopp's theoretical conclusions hardly admit of the
generality which he assumed them to possess, his experimental work
remains unassailed and unassailable, a monument to his ingenuity,
manipulative skill, his rigid sense of accuracy, and illimitable
patience.
T. E. T.
Dr. JOHX RAE, LL.D. (Edin.), a traveller in Arctic America, of
extraordinary energy and endurance, a keen observer of Nature, and
the discoverer of the fate of the Franklin expedition, was born in
Orkney in 1813, died in London in 1893, and is buried in the
cathedral of St. Magnus at Kirk wall, where a statue is erected to his
memory.
He qualified as a surgeon in Edinburgh, and as such he accom-
panied one of the ships of the Hudson's Bay Company, whose service
he joined, and then for ten years he resided at Moose Factory.
(1) His first journey of pure exploration was a boat voyage along the
coast of Hudson's Bay to Repulse Bay, where he wintered, and, in
the following year he surveyed a coast line of 700 miles, connecting
the surveys of Ross in Boothia with those of Parry at Fury and
Heckla Strait. (2) Next he joined the expedition of Sir J. Richard
b 2
VI
son in 1848 in search for Sir J. Franklin, during which the whole
coast was explored that lay between the mouths of the Mackenzie and
the Coppermine Rivers. (3) In 1851, at the request of Government,
he explored and mapped, with the slenderest outfit, 700 miles of the
south coast of Wollaston Land and Victoria Land, still in search of
Sir J. Franklin, for which achievement he received the gold medal of
the Geographical Society. Its result was greatly to narrow the range
of possibilities as to the locality of the missing expedition. (4) He
took charge of a boat expedition, proved the insular character of
King William's Land, and came at last upon relics of Franklin's party
and received verbal information from the Eskimo that gave the first
definite information as to their fate. The disaster occurred at the
mouth of the Back River, a little more than 200 miles in a direct line
from the place where he heard of it. For this achievement he
received the promised grant of £10,000 from Government. He did
not visit the spot himself, but his information as to the site and the
completeness of the disaster, was soon abundantly confirmed. After
this he made some further travel of interest, though by no means of
the importance of the above, surveying a route for a telegraph line
across Iceland and in North America.
This bald statement of itineraries will give but a poor idea, except
to Arctic travellers, of the severity of the work accomplished. To
supply the deficiency, the following quotation is given from the
address of Sir R. Murchison when presenting the Gold Medal to
Dr. Rae; his remarks chiefly referring to the journeys numbered
above as (1) and (3).
" With a boldness never surpassed, he (Dr. Rae) determined on
wintering on the proverbially desolate shores of Repulse Bay, where,
or in the immediate neighbourhood, one expedition of two ships had
previously wholly perished, and two others were all but lost. There
he maintained his party on deer shot principally by himself, and spent
ten months of an Arctic winter in a hut of stones, the locality not
even yielding drift timber. With no other fuel than a kind of hay
made of the Andromeda tetr<tgona, he preserved his men in health, and
thus enabled them to execute their arduous surveying journeys of
upwards of 1,000 miles round Committee Bay (the southern portion
of Boothia Gulf) in the spring. Next season he brought his party
back to the Hudson Bay posts in better working condition than wlier
he set out, and with but a small diminution of the few bags of pro-
visions he had taken with him.
" On his last journeys, in which he travelled more than 3,000 miles
in snow-shoes, Dr. Rae has shown equal judgment and perseverance.
Dreading, from his former experience, that the sea might be frozen,
he determined on a spring journey over the ice, and performed a most
extraordinary one. His last starting place at Fort Confidence on the
Vll
Great Bear Lake, being at a distance of more than 150 miles from
the coast by the route he was compelled to take, he could not, as in
the parties of our naval expeditions, travel on the ice with capacious
sledges, and was, therefore, obliged to restrict his provisions and
baggage to the smallest possible weight. With a pound of fat daily
for fuel, and without the possibility of carrying a tent, he set out
accompanied by two men only, and trusting solely for shelter to snow
houses he taught his men to build, accomplished a distance of
1,060 miles in 39 daya, or 27 miles per day including stoppages, and
this without the aid of advanced depots, and dragging a sledge him-
self great part of the way. The spring journey, and that which
followed in the summer in boats, during which 1,700 miles were
traversed in 80 days, have proved the continuity of Wollaston and
Victoria lands along a distance of nearly 1,100 miles, and have shown
that they are separated by a strait from N. Somerset and Boothia,
through which the flood tide sets from the north. In this way Dr.
Rae has performed most essential service, even in reference to the
search after Franklin, by limiting the channels of outlet between the
continent of America and the Arctic Islands."
It is easy to understand that Dr. Bae's views as to the equipment
of expeditions in Arctic travel would differ in many respects, rightly
or wrongly, from those who advocated the costly naval expeditions
then in vogue. He could point to instances of his own superior
success, and to the disasters that befel the survivors of the Franklin
expedition, as they toiled homewards with a miscellaneous collection
of heavy articles. Putting forward his views, as he did with point
and insistence, his remarks were, as a rule, somewhat unwelcome to
the naval authorities.
In early middle life Dr. Bae was remarkable for manly beauty in
form and feature, combined with a temper that was quick and some-
what fiery. In a book on Ethnology, where each of the human races
was represented by a single specimen, it was noticed that an old
photograph of Dr. Bae had been utilised to represent the Caucasian
type.
Dr. Bae's house contained an interesting series of specimens illus-
trating the fauna and flora of arctic America and the domestic
methods of the Eskimo, which he delighted to show and to explain,
for he was a most courteous host, well aided by his wife. As a
narrator he was delightful, being always lucid while full and circum-
stantial. His memoirs and speeches were stamped throughout with
those characteristics.
His interest in the regions where he gained his fame remained
unabated to the last. He died, regretted by many friends, in his
eightieth year.
F. 0
Vlll
FRANZ ERNST NEUMANN was born on September 11, 1798, at Joa-
chimsthal, a small town about forty miles to the north-^ast of Berlin.
At the early age of seventeen he entered the army as a volunteer
to fight against Napoleon in the campaign of 1815. A serious
wound, received in the battle of Ligny, kept him to his bed for many
weeks ; but, on recovery, he once more joined the army. At tbe
end of the war he returned to his lessons at the " Gymnasium "
of Berlin, and subsequently entered the University as a student of
theology. Soon afterwards he migrated to Jena, where he came under
the influence of C. S. Weiss, the Professor of Mineralogy, and
turned his attention to that subject. His papers, published between
1823 and 1830, all referred to crystallography,- and even his earliest
work attracted attention, and left a lasting impression on the science
of mineralogy. It secured him a call to the University of Kchiigs-
berg as " Privat-docent," where Bessel, Jacobi, and Dove became his
colleagues. Under their influence he gradually drifted more and
more towards the study of physics. His knowledge of mathematics
was acquired by private study, for although the University of Berlin
nominally possessed a teacher of mathematics, no lectures were given.
If the circumstances of Neumann's early education are considered,
it is remarkable that he obtained such a command of mathematical
physics, and this seems to have been ascribed by himself to the
careful study of Fourier's writings, which he admired to such an
extent that he made a manuscript copy of the great treatise on the
' Conduction of Heat.' In the year 1828 Neumann was appointed
Professor Extraordinarius at a salary of 200 thalers (£30). Bessel,
who had formed a high opinion of his powers, wrote in the same
year a letter to the Minister of Education pressing Neumann's claim
to a better position. The letter had the desired effect, and Neu-
mann was nominated, in 1829, Professor Ordinarius, and his salary
raised to £75. He never left Konigsberg, continuing his professorial
duties until 1876, and died on May 23, 1895.
Among his earlier papers on physical subjects, attention must
be drawn to one on the specific heat of minerals (Pogg. Ann.,
1831). It contains an extension of Dulong and Petit's law of specific
heats to compound bodies having a similar chemical constitution,
but is chiefly valuable for the improvement, both in the methods
employed and in the theoretical discussion of the experimental results.
It is shown how the method of mixture may be applied to the case
of badly conducting substances. The second paper treats of the
specific heat of water. The older observers had stated that when
hot water is poured into cold water, the resulting temperature of
the mixture is lower than tha.t calculated, on the assumption that
the specific heat of water is constant. Neumann showed that this
result is due to errors of experimentation, and demonstrated with
IX
improved apparatus, that the specific heat of water increases with
rising temperature. On the assumption that the rate of change is
uniform, Neumann calculated the ratio of the specific heats at 100°
and 0° to be 1-0176. The assumption made is now known to be
incorrect, but it cannot be said that Neumann's experimental result
has been much improved upon by later investigators. Although
nearly all fields of physical science have at different times been
successfully treated by Neumann, his fame chiefly rests on his theo-
retical investigations in optics and electricity. After Fresnel's
fundamental researches, which had shown the possibility of ex-
plaining the most complicated optical phenomena by the undulatory
theory, it became necessary to connect that theory more closely with
the conditions of wave-propagation in ordinary elastic bodies. In
other words, an elastic solid theory of the ether formed the next step
to be taken, and the name of Neumann will always remain associated
together with that of Cauchy, McCullagh, and Green in the early
efforts to found a truly dynamical theory of light. In the first paper,
" Theorie der doppelten Strahlenbrechung abgeleitet aus den Glei-
chungen der Mechanik," Neumann obtains a wave-surface identical
with that deduced somewhat earlier by Cauchy. In the case of
biaxal crystals it does not agree with that of Fresnel. It consists of
three sheets, one of them being due to the longitudinal wave. The
difference of the two other sheets with Fresnel's surface is, however,
more nominal than real, for as Stokes pointed out, in his Report on
Double Refraction, the difference may, by proper adjustment of
the constants, be made to show itself only in the tenth place of
decimals. The same report gives full details on the comparison
between the theories of Cauchy, Neumann and Green. A further
important contribution to optics was made in the year 1835 under
the title " Theoretische Tint ersuchun gen der Gesetze, nach welchen
das Licht an der Grenze zweier vollkommen durchsichtigen Medien
reflectirt und gebrochen wird." This paper raises the difficult ques-
tion of the mathematical expression for the conditions which must
hold at the surface separating two crystalline media. For well con-
sidered reasons Neumann adopts the view that the density of the
ether is the same in all media, and follows out this hypothesis to its
logical consequences. The same problem was treated at the same
time by McCullagh by very different and simpler methods, but the
results of both investigators were identical. Neumann further con-
firmed his equations by experiment. The general acceptance of the
electromagnetic theory has now considerably changed our point of
view, but the historical importance of Neumann's work must be con-
ceded in spite of certain defects which may, with justice, be urged
against it.
Several further papers treated of optical subjects, amongst which,
perhaps, the most important refers to double refraction in strained
uncrystalline bodies.
Neumann* next turned his attention to electricity, and in two im-
portant papers, published in 1845 and 1847, established the laws of
induction of electrical currents. We meet here, for the first time,
with the " electrodynamic potential." It is shown how currents,
induced in one circuit either by the motion of conductors carrying
electric currents, or by a change in the intensity of the current, may
be deduced from one function depending on the relative position of
the conductors, and that this function will also determine the
mechanical forces acting between the conductors. To appreciate
fully the great advance which was made by these two memoirs, it is
necessary to realise that the papers were published before it had been
shown, by Helmholtz and Lord Kelvin, how the principle of the con-
servation of energy may be utilised in the treatment of the problem.
It may also be pointed out that Neumann's investigations are deduced
from Lenz' laws, which are direct consequences of the principle of
energy ; so that Neumann's treatment may, indirectly, be said to
depend on that principle.
Neumann was the first to solve the problem of the magnetisation
induced in an ellipsoid of revolution under the action of any mag-
netic forces. Other important contributions relate to the functions
known as spherical harmonics. It is a matter for regret that his
first paper on that subject (4 Astronomische Nachrichten,' 1838) was
completely overlooked by magneticians until Ad. Schmidt recently
drew attention to it. The method which might with great
advantage have been employed in the treatment of terrestrial mag-
netism, may be explained by reference to the simpler problem of
expanding a function of one variable by means of Fourier's series.
For instance, if the daily changes of temperature are to be expressed in
such a series from hourly readings of the thermometers, a very simple
and well-known process leads to the determination of the constants.
Neumann's investigations led him to an analogous process for the
expansion of a function in a series of spherical harmonics, the func-
tions having known values at the points of intersection of certain
latitude and longitude circles on a sphere.f
Neumann's last publication was a memoir (edited by his son, C.
Neumann), ' Beitrage zur Theorie der Kugelfunctionen,' which con-
tains many interesting theoretical researches on that subject.
* Neumann's initials are often incorrectly given ; thus, in the text of Maxwell's
' Electricity and Magnetism ' (second edition) he is uniformly quoted as
J. Neumann.
f In both the problems mentioned the values of the constants are really indeter-
minate, but the solution gives, under certain assumptions, their most probable
values. Care should be taken that in any actual problem the assumptions are really
justified.
Neumann's publications are not sufficient to give an adequate idea
of his life's work. As a teacher he exerted a wide-spread influence,
and the progress of physical science in Germany is largely indebted
to the stimulating influence which he exercised, especially with the
help of the « Mathematisch-Physikalisches Seminar,' founded by him
in conjunction with Jacobi and Sohnke. The object of this institu-
tion was to supplement the teaching given in lectures, and to intro-
duce students into the methods of original research. Exercises were
set to the students by the directors of the seminar, and, as Neumann
himself explained, " In the choice of problems I laid stress on their
referring to points of practical importance, such as the application
of Gauss' theory of principal points and planes in a system of lenses ;
or that the selected exercise should lead students to an experimental
investigation of a problem which they had treated in a theoretical
manner."
There was never, probably, a school of original research conducted
in so systematic a manner as this seminar, in which Neumann was
the leading spirit. Annual reports of the work done by each student
were sent in to the Prussian Minister of Education, and, occasionally,
money prizes were given for a research of special merit. An interest-
ing account of the history of this seminar is contained in a notice of
Neumann's life by P. Volkmann.* Its importance may be recognised
by the fact that Kirchhoff's first papers on the distribution of electric
conductors, and H. Wild's construction of his photometer and polari-
meter, figure amongst the direct results of the teaching given in the
seminar. Kirchhoff's great powers were soon recognised by Neumann,
and when, in the year 1846, Neumann had set as a special prize problem
" The determination of the constants on which the intensity of in-
duced currents depends," the prize was awarded to him for a research
which contained the first measurement of a resistance in electro-mag-
netic measure. Neumann's success as a teacher will be appreciated
by reference, in Volkmann's publication, to the doctor dissertations of
his pupils, which were carried out under his guidance.- Amongst the
students who flocked to hear his lectures at Konigsberg, we find
Borchardt, Durege, Lipschitz, Kirchhoff, Wild, C. Neumann, Clebsch,
Auwers, Quincke, and Voigt.
Neumann was elected a Foreign Member of the Royal Society in
1862, a Corresponding Member of the French Academy in 1863, and
received the Copley Medal in the year 1887.
A. S.
* Leipzig (G-. Teubrier), 1896. I owe to this publication and to Mr. Voigt's
notice in 'Gottingen, Nachrichten,' 1895, p. 248, nearly all the information given in
the above obituary notice.
VOL. LX,
XI 1
By the death of Sir JOSEPH PRESTWICH British geological science
loses one of its oldest, as well as one of its most distinguished
votaries. Descended from an old Lancashire family (in which, for
some cause or other, a baronetcy has lain dormant for some genera-
tions), he was born at Pensbury, Clapham, on March 12, 1812.*
After some preliminary schooling he was sent to Paris, where he
remained for two years in a school attached to the College Bourbon.
He was then transferred to Dr. Yalpy's, at Reading, and finally
entered University College, London, soon after its establishment.
He there worked diligently in the chemical and natural philosophy
classes under Dr. Turner and Dr. Lardner, availing himself also of
the geological and mineralogical collections in the British Museum.
While still at College he started a Society among his fellow
students, each member of which had in his turn to deliver a lecture
on chemistry or some branch of natural philosophy. This " Zetetical
Society" had rooms of its own, and a small laboratory, in Surrey
Street, Strand. It consisted of about fourteen members ; but its
existence was of limited duration. Mr. Prestwich himself was called
away from it to join the business of his father, who was a well-known
wine merchant in Mark Lane ; and he remained closely connected
with the house and business for nearly forty years. Happily, his
commercial avocations to some degree aided, instead of restricting, his
pursuit of geological studies. He had to make frequent visits to
France and Belgium, in both of which countries he formed lasting
friendships with the leading geologists and palaeontologists of the
day; and he made himself personally familiar with the actual strata
and fossils which they had described. Not only so, but his business
among the country connexions of the firm carried him to nearly
every part of the United Kingdom, and the hours unclaimed by his
engagements were enthusiastically devoted to the study of the local
geology of the districts he visited. His comprehensive eye enabled
him rapidly to appreciate and to grasp the leading features, topo-
graphical and geological, of most of the areas which in those days
possessed an exceptional geological interest ; and those who in later
years had the good fortune to accompany him to such spots were sur-
prised to find how retentive was his memory and how intimate was
his acquaintance with every pit, quarry, and rock-section that in any
way illustrated the geological problem under consideration.
His first published papers dealt with the fossil-bearing deposits of
the neighbourhood of Gramrie, Banffshire — particularly with the strata
containing ichthyolites, and with the shell-bearing layers of the Till —
and the international character of his geological work was exhibited
* For much that is here said I am indebted to a memoir by Dr. Henry Wood-
ward, F.R.S., published in the ' Geological Magazine,' 1893, p. 242. I have also to
thank Professor Lapworth for kind assistance.
Xlll
by his following paper, on " Les Debris de Mammiferes terrestres
qui se trouvent dans 1'Argile plastique aux Environs d'Epernay."
Though written at an earlier date, these memoirs were not published
until 1837. He had already, in 1833, become a Fellow of the Geological
Society. His memoir on the " Geology of Coalbrookdale," published
in the Transactions of that Society in 1836, was founded mainly on
visits made to Coalbrookdale in the years 1831 and 1832. This work,
which was accompanied by descriptions of new plants and mollusca
by his friend Professor Morris, was the earliest monograph on the
structure of a British coalfield. It at once established his reputation
as a geologist, and it has ever since been numbered among our
British classics.
From about 1846 onwards for several years, his attention was
mainly concentrated upon the tertiary deposits of the London basin,
and he published a work on the water-bearing characters of these
deposits in 1851. But the scientific results of his investigations
were of far higher importance. He not only reduced the little
known English tertiaries into proper system (establishing the sepa-
rate existence of certain local beds to which he gave the name of the
Thanet Sands, proving the synchronism of the Reading beds with
those of Woolwich, and fixing the true position of the London clay
with respect to the Hampshire basin), but he succeeded in correlating
the tertiary beds of England, France, and Belgium in such a manner
that his classification was accepted by most geologists, and has stood
the test of time.
This comprehensive study of the tertiary group naturally led Mr.
Prestwich onward to the investigation of the later and more superficial
deposits ; and the acquaintance which the writer of these pages had the
good fortune to form with him in 1851, led to an enduring friendship and
constant intercourse, as well as to occasional geological excursions with
him to spots where these drift and alluvial deposits could be examined.
In the winter of 1858, Dr. Hugh Falconer urged upon Mr. Prestwich's
attention the desirability of investigating in the field the evidences for
the discoveries of M. Boucher de Perthes of flint implements of pre-
historic man in the gravel deposits of the Valley of the Somme, which
were then somewhat doubtfully received, and in April, 1859, Mr.
Prestwich proceeded to Abbeville, where he was joined by Mr. John
Evans. Thence they went to Amiens, and in the gravel beds of St.
Acheul saw for themselves, still embedded in its matrix, one of those
implements of unquestionable human workmanship, the asserted
existence of which in the alluvial deposits had met with so much doubt.
The previous discoveries, thus verified and subsequently supplemented
by researches conducted on lines which could with confidence be
laid down, soon led to an entire revolution in the then existing
ideas as to the antiquity of man. Not that the new views were at
XIV
once accepted, or that the advocates of the old ideas were backward
in their defence of them. For years controversy was long and
occasionally loud ; but so completely has it now died out, that the
promoters of what were then new views occasionally find themselves
at the present time in antagonism with the promoters of views newer
still, for which they are not quite satisfied that there is as yet sufficient
foundation.
At various intervals, from 1859 onwards, Mr. Prestwich wrote
several papers relating to post-Pliocene deposits, including one of
great importance, " On the Loess of the Valleys of the South of
England and of the Somme and of the Seine," communicated to the
Royal Society in 1862. He had previously furnished to the Society
an account of the discoveries of flint implements at Abbeville,
Amiens, and Hoxne.
In 1866 and 1867 Mr. Prestwich rendered valuable aid to the
country by acting on the Royal Coal Commission, and on that on the
Metropolitan Water Supply. In connection with the former he
furnished an exhaustive, and at the same time suggestive, Report
(published in 1871) "On the Probability of finding Coal under the
Newer Formations of the South of England " — some of the anticipa-
tions in which he lived to see at all events partially realised.
With regard to the latter subject, his book, ' The Water-bearing
Strata of the Country around London,' gave evidence of his capacity
to speak.
During all these years Mr. Prestwich had been actively engaged
in business, and it is amazing to note the amount of detailed and
accurate geological work that he was able to accomplish. But about
1872 he managed to emancipate himself in a great measure from the
trammels of trade, and in 1874 he was appointed to succeed the late
Professor Phillips in the Chair of Geology at Oxford. He was there
able to devote nearly the whole of his time to the prosecution of his
favourite study, and to enlisting recruits for the science.
It is impossible in a notice of this kind to cite even the titles of his
numerous papers, but especial mention may be made of his memoirs
" On the Temperature of the Sea at various Depths below the
Surface," and " On the Origin of the Parallel Roads of Lochaber "
(printed in the 'Philosophical Transactions'), as well as those on
" Underground Temperature " and on the evidences of the " Sub-
mergence of Western Europe."
To the Institution of Civil Engineers he communicated essays on
the " Geological Conditions affecting the Construction of a Tunnel
between England and France," and on the " Origin of the Chesil
Beach," for which a Telford Medal was awarded him.
His papers read before the Geological Society were numerous.
Among his later ones, those on " Volcanic Action," on the " Mundesley
and Westleton Beds," on the " Relation of the Glacial Period to the
Antiquity of Man," on the " Pre-glacial Drifts of the South of
England," and on the "Age of the Valley of the Darent," may,
perhaps, be described as the more important.
It was while living at Oxford that he produced, in 1886 and 1887,
his great work in two volumes on " Geology, Chemical and Physical,
Stratigraphical and Palaeontological." In this work he not only
brought forward many arguments against carrying the doctrine of
uniformity too far in attempting to read the history of the earth, but
at the same time he showed some signs of reverting to theories
involving more of cataclysmic action than most modern geologists are
willing to allow. As a whole, however, his book is a monument of
patient and conscientious work, and is likely long to retain the
high position that it holds at present in geological literature.
As already stated, Mr. Prestwich was elected a Fellow of the
Geological Society so long ago as 1833. From 1856 onwards he for
many years served the Society as Treasurer, becoming President for
two years, from 1870 to 1872. Already in 1849 the Wollaston Medal
had been awarded him for his researches at Coalbrookdale and in the
London Basin.
In 1853 he was elected a Fellow of the Royal Society, and at
intervals served upon its Council, during seven years in the aggre-
gate. In 1870—1871 he was a Vice-President of the Society. One
of the Royal Medals was awarded to him in 1865 for his contribu-
tions to geological science.
In France the name of Prestwich was almost as well known as in
England. He was one of the oldest members of the French
Geological Society, and when it was assembled at Boulogne, in 1880,
he was appointed President of the meeting. In 1885 he was elected
a Corresponding Member of the Institut (Academie des Sciences).
He was also a Foreign Member of the Accademia dei Lincei, at Rome,
of the Geological Institute of Vienna, and of various academies in
Belgium, Switzerland, and the United States of America. When the
International Geological Congress met at London in 1888, the esteem
with which he was regarded by geologists of all nationalities was
shown by his unanimous election as President of the Congress.
He retired from the Geological Chair at Oxford in 1888, to the
great regret of his brother professors, and of his numerous friends in
that University, which conferred upon him in the same year, as a
tribute of esteem, the honorary degree of D.C.L. After his retire-
ment he resided for the most part at his delightful country house,
Darent Hulme, Shoreham, Kent, which he built, in accordance with
his own tastes some twenty-seven years ago, and every room and wall
of which brought to mind some subject of geological interest, either
in material or decoration. There he actively continued his scientific
XVI
labours, efficiently aided and cared for by a loving wife — the niece of
his old friend, Dr. Hugh Falconer.
The first public recognition of his services, both to science and
the State, was accorded him at the beginning of the present year,
when he received the honour of knighthood, with the unanimous
acclaim of the scientific world. But he was, alas ! not destined to
bear his honours long, and, after some months of great physical
weakness, he died on June 23rd, 1896.
Of his personal amiability, his devoted friendship, and his charm
of manner, this is hardly the place to speak : but all those with whom
he was brought into contact will agree that in Sir Joseph Prestwich
we have lost not only one of the great pillars of geological science,
but a geologist whose mind was as fully stored with accumulated
knowledge as that of any of his contemporaries, and one who was
always ready to place those stores generously and freely at the
disposal of others.
J. E.
GKORGE JOHNSON was born in November, 1818, at Goudhurst, in
Kent, and he received his education at the Grammar School there.
In 1837 he paid a visit of some weeks to an uncle who was a medical
practitioner in Cranbrook, and became so enamoured with the life of
a country doctor that he decided to join his uncle as an apprentice.
There he remained for two years and a half, and then entered the
medical department of King's College, London, with which institu-
tion his name has been so intimately connected ever since. His
college life was a highly distinguished one; he obtained numerous
prizes and scholarships both at the College and at the University of
London, where he took his degree of M.D. in 1844. At King's
College Hospital he served as clinical clerk to Dr. Todd, and dresser
to Sir William Ferguson ; later on he became house physician, house
surgeon, and, in 1843, resident medical tutor. At the end of his
college course he was elected an Associate of King's College.
This brilliant academical career altered his intention of becoming
a country practitioner, and he decided to remain in London. In
1846 he became a Member of the Royal College of Physicians, and
four years later was elected a Fellow. At the College of Physicians
he filled many important offices, including those of Examiner in
Medicine, Councillor, Censor, Vice-President, Goulstonian Lecturer,
Lumleian Lecturer, and Harveian Orator. In 1862 he was appointed
a Senator of the University of London ; in 1872 he became a Fellow
of the Royal Society ; and, in 1884, President of the Royal Medical
and Chirurgical Society.
His appointments at King's College Hospital were those of
Assistant Physician (1847), Full Physician (1856), Professor of
XV11
Materia Medica (1857), and Professor of Medicine, in succession to
Dr. George Budd (1863). In 1886 he resigned this post, and was
elected by the Council, Emeritus Professor of Clinical Medicine, and
Consulting Physician to the Hospital. Shortly after this he became
a Member of the Council of King's College, in which position he con-
tinued to serve his alma mater until his death.
In 1883, Dr. Johnson was appointed by the Prince of Wales Con-
sulting Physician to the Royal College of Music ; in 1885 he received
the honour of being elected a member of the Atheneeum Club, on the
ground of his eminence in science; in 1888 his past and present
students and friends presented him with his portrait, painted by the
late Mr. Frank Holl, R.A. This picture was publicly presented to
him in the large theatre of King's College amid a crowd of his
former colleagues and friends by Sir Joseph Lister. The scene will
long be remembered by all those who heard Sir Joseph Lister's
kindly words, and Dr. Johnson's emotional reply. In 1889 he was
made Physician Extraordinary to the Queen, and in 1892 he received
the honour of knighthood.
The following list comprises his principal contributions to litera-
ture : — " On. Diseases of the Kidney, their Pathology, Diagnosis, and
Treatment " (1852) ; " Lectures on Bright's Disease " (1873) ; " Epi-
demic Diarrhoea and Cholera " (1855) ; " Notes on Cholera "
(1856); "The Laryngoscope" (1864); "A Defence of Harvey as
the Discoverer of the Circulation of the Blood" (1884) ; this was a
reply to certain criticisms evoked by his Harveian oration of 1882.
In 1887 he published a collection of medical essays and lectures in
which many of his former ideas were stated with new force. Sir
George Johnson's scientific life was by no means a peaceful one, and
led to much controversy ; he continued to take part in discussions
arising from his work until the very last. In 1894, in a series of
letters to the 'Lancet,' he maintained, in opposition to Dr. Pavy,
that normal urine contains no sugar, but that the principal reducing
substance present is creatinine, a material which he and his son
(Mr. G. S. Johnson) very thoroughly investigated. In 1889 he
published an essay on "Asphyxia," in which he defended his well-
known views against those of his opponents. As late as 1895, a
'History of the Cholera Controversy,' in which Sir George played
so prominent a part, appeared from his pen ; and in the present year
a similar book on ' The Pathology of the Contracted Granular
Kidney ' completed his long series of publications.
He married, in 1850, Charlotte Elizabeth, youngest daughter of
the late Lieutenant White, of Addington. He was left a widower
with five children ten years later.
The vigour of Sir George Johnson's mind remained unimpaired to
the last, but his bodily health was feeble. He suffered from paralysis
xvni
agitans, was subject to insomnia, and was slightly deaf. These
infirmities rendered his attendance at public meetings somewhat
irregular, but when questions of urgency arose he was always at his
post at the Senate of the London University, the Council of King's
College, and the meetings of the College of Physicians. During the
last three or four years, however, his health had improved, and he
was able during his summer holidays to resume his shooting in
Scotland, a sport of which he was extremely fond. Only last
summer he related with pride how he had brought down a stag at
the distance of so many yards. His house in Saville Bow contained
many trophies of the chase. His sudden end on Wednesday, June 3,
1896, therefore came as a surprise and shock to all his friends. The
cause of death was apoplexy. The morning of Monday, June 1, he
was in his usual health, and he employed it in writing a paper which
was published in the * Lancet ' of June 13, under the appropriate title,
" A Last Word on Cholera." This was a brief criticism on Dr. Ken-
neth Macleod's article on "Cholera," in Dr. Clifford Allbutt's
' System of Medicine.' In the afternoon he went out for his usual
drive, and it was on his return that he was seized with hemiplegia.
Though he regained sufficient consciousness to recognise those about
him, he never rallied, and died within forty -eight hours of the
attack.
The funeral took place on June 8, after a preliminary service at
St. James's, Piccadilly, conducted by Dr. Wace, Principal of King's
College, and attended by a large number of his friends and admirers,
Sir Joseph Lister representing the Royal Society ; the remains were
laid to rest by the side of those of his wife at St. Mary's, Addington.
The medical and scientific world has lost a distinguished ornament,
an earnest and steady worker, a deep thinker, a vigorous writer, and
a lovable and tender-hearted friend.
The foregoing enumeration of the principal incidents in his life
shows how full it was of active service, but cannot paint the man as
he was to those who knew him. The readers of his works will see in
him the trenchant writer, and the uncompromising but always fair
defender of his views. Those who listened to his lectures will
remember the well ordered, logical, and clear exposition of his
thoughts ; here he never allowed his strong but contentious ideas to
appear in undue relief when he was teaching his students. His
opponents will know him as a hard hitter, but one who was always
ready to acknowledge his own mistakes, and who never carried his
words into the region of personal attack. It is, however, only those
who sat with him by his fireside who can properly realise the gener-
ous friend, the lovable disposition, the keen interest he always took
in questions of science, and the enthusiasm with which he followed
up his theories. It was especially the younger men with whom he
XIX
liked thus to show his sympathy, and among his scientific friends he
used to say that above all he dearly loved to chat with the physio-
logists.
It is somewhat difficult for one like the present writer, who only
knew Sir George during the last ten years or so of his life, to guess
who among his earlier friends had most to do with the formation of
his character. Sir George had obviously a strong character of his
own, which would have brought him to the front in any walk of life;
but to judge by his conversation on the reminiscences of his younger
days, it would seem that above all others, Dr. Todd was the one who
especially stimulated him in the particular branches he took up. At
the time that he was student, Dr. Todd was Professor of Physiology
at- King's College, and throughout the whole of his subsequent life,
Johnson was as diligent a student of physiology as ho was of
medicine. He knew, in a most surprising way, the contents of
modern physiological text-books, especially in relation to the circula-
tion of the blood, his favourite study ; and, to show the vigour of his
mind, he was intensely interested towards the last in the question of
osmotic pressure, a difficult subject which has only recently attained
importance to physiologists. He was, however, not merely a student
of books, but was practical to the backbone ; after the establishment of
the physiological laboratory at King's College, during the time Pro-
fessor Rutherford occupied the chair of physiology, he was a frequent
visitor there, and much important work was done at his suggestion
then and subsequently. He was an accomplished histologist, and
took a keen delight in showing to his friends the specimens by which
he believed he had refuted the views of those who disagreed with
him. Even in the last week of his life he had commenced experi-
ments on the action of the cilia in the renal tubules of the newt's
kidney.
In mentioning his early friends, one must not omit to enumerate
Sir Thomas Watson, whom he helped with his celebrated lectures ;
Sir William Ferguson, Sir William Bowman, and Dr. Bristowe, all
of whom Sir George Johnson survived.
The controversies of his life were numerous ; there were stormy
times at King's College, especially in years now far back ; there was
the great cholera controversy : in the first years of this, Johnson was
most unfairly treated, being branded almost as a quack in the
medical journals. He, however, in spite of loss of practice, stuck to
his views, and had, in the end of his days, the satisfaction of seeing
his evacuant treatment of cholera regarded as a rational one, and in
many cases recognised by eminent practitioners as the correct one.
Of his sobriquets, Johnson preferred to be known as " Cholera John-
son " rather than "Kidney Johnson." His views on the kidney
question were direct deductions from physiological knowledge derived
VOL. LX. **
XX
from the discovery of the muscular structure of the arterioles by
Henle, and the work of Claude Bernard on vasomotor nerves. His
views on the cause of the hypertrophied heart in cases of Bright's
disease are now generally regarded as correct. His ideas on
asphyxia, which he continued to the last to call by the old-fashioned,
but etymologically correct, name, apnoea, formed the subject of
another spirited debate ; and, in conclusion, one must mention a con-
troversy of another kind, the dispute with Sir William Gull over a
point of professional etiquette connected with the " Balham Case."
The point was decided in Johnson's favour by the College of
Physicians, but the incident left a good deal of bitterness behind it.
Still this long series of straggles did not embitter Johnson's life.
He was always able to discuss the matters involved without a trace
of ill-feeling, though a mention of any one of them would lead him
into a prolonged and forcible exposition of his own views.
In his later essays he was able to write with calmness, and was
willing to leave to time the recognition of what was true in the active
and full life-work, which he must have known was then drawing to a
close.
W. D. H.
HENKY NEWELL MARTIN was born on July 1, 1848, at Newry,
County Down, Ireland. He was the eldest of a family of twelve, his
father being at the time a Congregational minister, but afterwards
becoming a schoolmaster. Both his parents were Irish, his father
coming from South Ireland, and his mother from North Ireland.
He received his early education chiefly at home ; for though he went
to several schools, his stay was not long at any one of them.
Having matriculated at the University of London before he was
fully sixteen years of age (an exemption as to age being made in his
favour), he became an apprentice to Dr. McDonagh, in the Hamp-
stead Road, London, in the neighbourhood of University College, on
the understanding that the performance of the services which might
be required of him as apprentice, should not prevent his attending
the teaching at the Medical School of the College, and the practice
at the hospital. During his career at University College he greatly
distinguished himself, taking several medals and prizes, in spite of
his time for study being, on account of the above-mentioned duties,
less than that of his fellow students. In 1870 he obtained a
scholarship at Christ's College, Cambridge ; he had, in the
summer of that year, conducted at Cambridge a class of Histology
for the late Sir G. Humphry. The writer of this notice had about
the same time been appointed Prselector of Physiology at Trinity
College, and the two went up to Cambridge together in the October
of that year. He at once undertook to act as the demonstrator of the
XXI
Trinity Prelector, whose right hand he continued to be in every
way during the whole of his stay at Cambridge. His energy and
talents, and especially his personal qualities, did much to advance
and render popular the then growing School of Natural Science in
the University. At that time there was, perhaps, a tendency on the
part of the undergraduate to depreciate natural and, especially, bio-
logical science, and to regard it as something npt quite academical.
Martin, by his bright ways, won among his fellows sympathy for his
line of study, and showed them, by entering into all their pursuits
(he became for instance, President of the Union and Captain of the
Volunteers) that the natural science student was in no respects
inferior to the others.
In Cambridge, as in London, his career was distinguished. He
gained the first place in the Natural Science Tripos of 1873, the
second place being taken by Francis M. Balfour ; at that time the
position in the Tripos was determined by the aggregate of marks in
all the subjects. While at Cambridge he took the B.Sc. and M.B.
London, gaining in the former the scholarship in Zoology ; he pro-
ceeded later to the D.Sc., being the first to take that degree in
Physiology. So soon as, or even before, he had taken his degree, he
began to devote some time to research, though that time, owing to
the necessity under which he lay of making money by teaching, was
limited ; his first publication was a little paper of the structure of the
olfactory membrane, which appeared in the ' Journal of Anatomy and
Physiology ' for 1873.
In the summer of 1874 he assisted the Trinity Preelector in intro-
ducing into Cambridge the course of Elementary Biology, which the
late Professor Hurley had initiated at the .Royal College of Science
during the preceding year. He subsequently acted as assistant in
the same course to Professor Huxley himself. One result of this was
that he prepared, under Huxley's supervision, a text-book of the
course which, under their names, appeared with the title ' Practical
Biology,' and which has since been so largely used.
In 1874 he was made Fellow of his College, and giving himself up
with enthusiasm to the development of natural and, especially, of
biologic science at the University, was looking forward to a scientific
career in England, if not at Cambridge. About that time, however,
the Johns Hopkins University at Baltimore was being established,
and such was the impression made by Martin upon those with whom
he came in contact, among others Dr. Gilman, of Baltimore, that in
1876 he was invited to become the first occupant of the Chair of
Biology which had been founded in the Johns Hopkins University.
This offer he accepted, and thus nearly the whole of his scientific
career was passed in America. He went out prepared to develop in
his new home the higher teaching of biologic science, especially that
XX11
spirit of research which alone makes teaching " high " ; and during
the rather less than a score of years which made up his stay at Balti-
more, he produced a very marked effect on American science, fully
working out the great aim of the University which had adopted him.
By himself, or in concert with his pupils, he carried on many im-
portant investigations, among which may especially be mentioned
those on the excised mammalian heart. He was the first to show
that by appropriate methods the excised mammalian heart may be
made the subject of prolonged study. One of these researches,
namely, that on the " Influence of Temperature," was made the
Croonian Lecture of 1883. His various contributions were, in 1895,
republished in a collected form by his friends and pupils in America,
under the title of "Physiological Papers." He sent out into the
States, from among his students, a number of trained physiologists,
fired with his own enthusiasm, who are continuing to advance the
science, and one of whom has succeeded him at Baltimore. He also
found time to write expository works, and his ' Human Body,'
' Briefer Course,' and ' Elementary Course,' deservedly became very
popular in the States.
Upon his first appointment he had the charge of the whole subject
of animal biology ; and since he was himself more distinctly a
physiologist, it was almost his first duty to secure or train up a
colleague who should devote himself to morphology. Martin early
saw the worth of one of his students, W. K. Brooks; to him he
gradually entrusted morphological matters, and thus prepared, not
only the way for a separate Chair of Zoology, but also the man to
fill it.
Martin married in 1879 Mrs. Pegram, the widaw of an officer in
the Confederate army ; but there was no issue, and in 1892 his wife
died.
Even before his wife's death his health had begun to give way ;
and after that event he became so increasingly unfitted for the duties
which his own previous exertions had raised to a very great import-
ance, that in 1893 he resigned his post.
After his resignation he returned to this country, for he had never
become an American citizen, and was looking forward to being able,
with improved health, to labour in physiological investigations, hither
at his old University or elsewhere in England. But it was not to be.
Though he seemed at times to be improving, he had more than one
severe attack of illness, and never gained sufficient strength to set
really to work. During the past summer he visibly failed, and while
he was striving to recover his strength by a stay in the quiet dales of
Yorkshire, a sudden haemorrhage carried him off on October 27, at
Burley-in-Wharfedale, Yorkshire.
Having been for so long a stranger to this count ry, Martin was,
XX111
personally, but little known in English scientific circles; in America,
however, not in Baltimore only, but in many other parts of the States'
especially among the younger physiologists, he has left behind him
a memory which will not soon pass away ; while those in this country
who knew the brightness of his early days will always hold him in
affectionate remembrance.
M. F.
BRIAN HOTTGHTON HODGSON, of the Bengal Civil Service, oriental
scholar, zoologist, and diplomatist, was born in February, 1800, at
Prestbury, Cheshire, and was the eldest son of B. Hodgson, Esq., of
Lower Beech, in that county. He belonged to a long-lived family •
his father attaining his ninety-second year, and a grandmother
and a great-grandmother their ninetieth. He was educated at
Dr. Davies' school, Macclesfield, and was, according to the wishes
of his greab uncle the Bishop of London, and relative the Dean of
Carlisle, intended for the Church ; but, having no desire for holy
orders, at sixteen years old a nomination to the East India College of
Haileybury was obtained for him. Pending the passing his pre-
liminary examination at Haileybury, young Hodgson was the guest
of Professor Malthus, then preparing the seventh edition of his
*' Principles of Population," who directed his attention to politics
as a career; whilst a casual presentation at the Governor's house
to Canning, then President of the Board of Control, who addressed
the youth with a brilliant sketch of the career possible to an
Indian civilian, fired him with ambition to become a diplomatist,,
of which his stirring career, at the Court of Nepal, was the fruit.
At Haileybury, Hodgson gained high honours in languages and
political economy, finally passing out in 1817 as " First of his
year." In 1818 he sailed for Calcutta, where he passed a year in
the College at Fort William, studying the vernacular, Sanskrit, and
Persian, and becoming a proficient in the latter. At Calcutta his
health broke down, and, after a severe attack of fever, no choice was
left him between abandoning the service or obtaining a hill appoint-
ment. The latter — an all but unattainable prize for an untried youth
—was, nevertheless, thanks to his early promise, and more to the
private influence of powerful friends with the Government, obtained
for him, and he was appointed Assistant to the Commissioner of
Kumaon, a province of the Western Himalaya ceded by the Ne-
palese a few years previously.
Fortunately for Hodgson, his chief, G. W. Traill, was a first-rate
official, and, equally fortunately, Kumaori was in a condition of
disorganisation and savagery that taxed the highest qualities of its
new rulers. It was Traill's first duty to obtain the confidence of a
people driven into the jungles of all but pathless mountains by the
VOL. LX. G
XXIV
alternating tyrannies of Affghans and G-hiirkas, and who recognised
but two classes of beings — themselves and their ghosts ; then to
introduce the rudiments of justice, and, finally, raise the condition
of the people to that of a prosperous British province. It was
during his two years' pupilage with Traill that Hodgson commenced
his zoological observations and those studies of the aboriginal tribes
of India and their languages, which he pursued throughout his
career ; and, so efficiently did he perform his official duties, that,
after two years (in 1820), he found himself unexpectedly promoted
to be Assistant to the British Resident at the Court of Nepal.
Here, however, a disappointment awaited him. He found the
Resident, the Honourable E. Gardner, giving effect to Lord Hast-
ings' wise policy of converting Nepal from a turbulent neighbour
into a quiescent, if not friendly, ally of the British power, and this
lie was doing so effectively that Hodgson found a truce established,
and no scope for his ambition as a politician and diplomatist. He
accordingly applied to Government for more active employment, and
was at once gazetted to the Secretariat of the Persian Department of
the Foreign Office, Calcutta, a step towards the highest positions in
the service. At Calcutta his health, as before, at once broke down, and
be was fortunate in being sent again (in 1824) to Nepal in a subordi-
nate position, awaiting the successorship to the Assistant Residentship?
which post had been filled up. This he obtained in the following
year, followed by that of Acting Resident on Mr. Gardner's retire-
ment (1829), and Resident in 1833.
It was during the enforced quiescence of Hodgson's first years in
Nepal that he undertook the systematic study of Nepalese and Tibetan
Buddhist literature, and the collection and description of the verte-
brata of the Himalaya. By his courteous treatment of the Lamas of
the temples of Katmandu and of the emissaries of the Grand Lama
•of Lhassa to the Nepal Court, he enlisted their active co-operation in
the purchase of MSS., and in procuring copies of others, some dating
bick to upwards of 1100 years before the Christian era, for which
latter purpose he kept a staff of cepyists in constant employ. So
impressed was the Buddhist hierarchy by his learning and labours, and
so great was his reputation, that the Grand Lama of Lhassa himself
S2nt him a copy of their classical scriptures, the Kaghyur and
Stangyur, in 347 folio volumes. Subsequently Hodgson procured
another copy which he sent to the college at Fort William, and which
is now in the library of the Bengal Asiatic Society. Altogether,
dating from 1824, he had given upwards of '270 volumes of Sanskrit
and Tibetan literature to British institutions, especially to the Indian
Government, and 147 to the Societe Asiatique de Paris. The receipt
of the latter in France, together with copies of his own researches in
Buddhism, were, as early as 1837, recognised by the bestowal on him
XXV
of the Foreign Fellowship of the above Societe, accompanied by the
award of a gold medal, inscribed " An fondateur de la veritable fitude
du Budhisme par les textes et les monuments." This was followed, in
1838, by the Cross of the Legion of Honour, and, in 1844, by his
election as a Correspondent of the Institute of France. Meanwhile
his contributions to his own Government lay unheeded in the cellars
of the old India House in Leadenhall Street ; and there they remained
till their transference to the present India Office, where the Kaghyur
and Stangyur* occupy an apartment to themselves, accessible to all.
Scarcely less valuable and as extensive were Hodgson's contribu-
tion to zoology, especially ornithology, which rival his Buddhistical
attainments. Throughout his residence in the Himalaya he was
himself an assiduous collector, besides keeping a staff of shooters
who penetrated even into Tibet, and oi stuffers and artists at the
Residency. He described systematically and minutely almost every
species which he procured, accompanying the descriptions with
anatomical details, and observations on their habits, nidification
(if of birds), and geographical distribution. He published 127
zoological papers, chiefly in the 'Journal of the Asiatic Society of
Bengal.' In 1843 and 1858 he placed 9512 specimens of Himalayan
birds, 9037 of mammals, and 84 of reptiles at the disposal of the
British Museum, together with 1853 drawings. Of the above the
duplicates were distributed to the chief museums of Europe and
America.
Very early in his career, Hodgson commenced a study of the ISTon-
Aryan Races of India, their origin, customs, their unwritten
languages, which he reduced to writing, their religions and geo-
graphical distribution. The results are embodied in twenty-seven
papers contributed (with one exception) to the 'Journal of the
Asiatic Society of Bengal.' These, in the opinion of Latham and
•other scholars, are of the highest value and rank as his chief services
to literature.
Mr. Hodgson was a zealous advocate of the employment of the
vernacular for instruction in the primary schools of India. In this
his great opponents were Macaulay, Sir L. Trevelyan, and H. H.
Wilson, who advocated English or a classical Oriental tongue. In
1835 he published two letters on the state of Education in India,
which first " lifted the subject out of the arena of public contro-
versy." For twenty years he persisted in his efforts, which were not
crowned with success till 1854, when the Court of Directors adopted
his views, which were further confirmed by the Education Commis-
sion of 1882.
But diplomacy was Hodgson's earliest and abiding ambition, and
* For a very imperfect copy of these works the Eussian Government lately paid
.£2000.
XXVI
for the exercise of this he had ample scope during the ten years of
his residence afc the Nepal Court. The latter, never friendly to the
British alliance, was distracted by the often murderous intrigues of
Raja, princes, queens, ministers, and a dominant military class of
aggressive disposition, and Hodgson's main efforts were directed to
the establishment of trading relations with Nepal, and to warding
off or rendering abortive measures that would have led to hos-
tilities with the Company's forces, especially during the crises of
the Chinese, Affghan, and Punjab Wars. He persistently advocated
the policy of enlisting the fighting class of Nepal in the British
Army as a safe outlet for its activity, and it was greatly due to his
influence with his friend Jung Bahadur, and his representations to
Lord Canning, then Governor- General, that the former placed a
Ghurka force at our disposal during the Mutiny.
In 1843 Mr. Hodgson retired from the service, and after a year's
visit to England, and disposing of his later collections, he returned
to India with the intention of pursuing chiefly his ethnological
studies. For this object he took up his residence at Darjiling, a
recently created health resort, nearly 7500 ft. above the sea, in the
unexplored Himalaya, east of Nepal. Here he resided for sixteen
years, in indifferent health, the result of repeated fevers in Nepal,,
but as indefatigable as ever in collecting and publishing in continua-
tion of his Buddhist, zoological, and ethnological work, and in fur-
therance of the adoption of vernacular education.
In 1858 he finally returned to England, and resided first at the
Rangers, Dursley, in Gloucestershire, whence he removed in 1867 to
the Grange, Alderley, in the same county, frequently visiting London
during the summer months. Latterly, the winters were passed at
fhe Villa Himalaya, Mentone. He married first, in 1863, Miss Anne
Scott, daughter of General H. A. Scott, R.A. ; and, in 1868, Susan,
daughter of the Rev. Chambre Townshend, of Derry, Cork, who-
survives him. He was elected a Fellow of the Linnean Society in
1835, and of the Royal in 1877 ; Corresponding Member of the
Royal Asiatic Society in 1828, and Vice-President in 1876 ; Corre-
spondent of the Zoological Society in 1859; D.C.L. (Oxon.) in 1889;
and Fellow or Correspondent of many other scientific and literary
bodies. The honours so early showered on him by France are given
above. In person Mr. Hodgson was very good-looking, and of singu-
larly frank and courteous bearing, communicative, and generous to a
fault. His was a remarkable case not only of inherited loiigevit}-,
but of complete recovery in after life from the effects of long-
continued and often serious indisposition in India. He was fond oi
out-of-door exercise, and hunted till disabled by accident at sixty-
eight. He retained his faculties but little impaired till his death in.
the summer of 1894, leaving no family. He was buried at Alderley,
J D TT
xxvn
WILLIAM CRAWFORD WILLIAMSON was born at Scarborough on
November 24, 1816. His father, John Williamson, who began life
as a gardener, was a man of considerable scientific attainments, and
was, for twenty-seven years, curator of the Scarborough Museum.
From him his son early acquired a practical knowledge of geology
and natural history. Williamson, in his recently published auto-
biography,* describes how, when a boy, his evenings, throughout a
long winter, were devoted to naming fossil specimens from the
neighbouring coast, with the aid of Phillips' « Geology of Yorkshire. '
"Pursuing/' he says, "this uncongenial labour, gave me in my
thirteenth year a thorough practical familiarity with the palseonto-
logical treasures of Eastern Yorkshire. This early acquisition
happily moulded the entire course of my future life."
Williamson in those early days came into contact with several
distinguished men of science, and, notably, with William Smith, the
father of English geology, who spent two years in the Williamsons'
house.
A little later, in 1832, he made the acquaintance of Murchison,
who was already a friend of his father's, and from whom the younger
Williamson received great kindness.
Williamson early adopted the medical profession, and during his
apprenticeship to a Scarborough apothecary, found time to carry on
his work in natural history, spending his holidays in shooting rare
birds, and collecting plants and fossils. He wrote a paper on rare
Yorkshire birds, when only about 16, and almost immediately
afterwards he made his first contributions to fossil botany, drawing
and describing many of the specimens for Lindley and Button's
' Fossil Flora of Great Britain.' More than thirty of the plates in
this well-known book bear his name.
A paper on the distribution of organic remains in the Lias series
of Yorkshire was read before the Geological Society of London, on
May 9, 1834, when the author had only attained the age of 17^, and
another in November, 1836, on the Oolitic fossils of the same coast.
These were remarkable contributions to science in themselves, and the
more so as coming from so young a worker; few naturalists can
have started serious investigation so early in life.
Before he was 18, Williamson appeared as an author on a very
different subject, for, in 1834, he published an account of the excava-
tion of a tumulus at Gristhorpe, near Scarborough. This, which
was probably his only archaeological publication, was important in
its effect on his scientific career, inasmuch as it brought the young
naturalist into communication with the distinguished geologist, Dr.
Buckland. Through his influence, this paper was reproduced in the
* ' Eeminiscences of a Yorkshire Naturalist,' by W. C. Williamson, Redway,
1896.
XXV111
Literary Gazette.' In a letter to Williamson, referring to thisr
Dr. Buckland said, " T am nappy to have been instrumental in
bringing before the public a name to which T look forward as likely
to figure in the annals of British science." " The letter of Dr. Buck-
land," says Williamson, " was one of those influences the effect of
which was unmitigatedly healthy."*
In 1835 Williamson was appointed curator of the museum of the
Natural History Society at Manchester, an office which he held for
three years while pursuing his medical studies. Several papers,
chiefly on geological subjects, were the fruit of this period. In 1840
Williamson left Manchester and came up to London, where he entered
as a student at University College. He here attended the lectures
of the botanist Lindley, who now for the first time made the personal
acquaintance of his young coadjutor.
While in London he was offered the post of naturalist to an expe-
dition up the Niger, an offer which, fortunately for him and for
science, he declined, for the undertaking ended disastrously.
After about a year's work in London, Williamson passed his
qualifying examinations at the Apothecaries' Hall and College of
Surgeons, and then returned to Manchester, where he at once com-
menced the practice of medicine. At first he found it necessary to
keep his scientific pursuits somewhat in the background, but this did
not last long. His interest in Ehrenberg's discovery of the Foramini-
fera in chalk led him to undertake microscopic research, a field of
inquiry on which he had not previously entered. His first histo-
logical investigation, in 1842, related to the development of bone, a
subject to which he returned a few years later. In the meantime he
engaged seriously in the study of Foraminifera, following up
Ehrenberg's work above referred to. Among the naturalists who
supplied him with material for this investigation was Charles Darwin,
then just returned from his famous voyage in the " Beagle." The
results of Williamson's studies were embodied in a paper published in
the ' Transactions of the Literary and Philosophical Society of Man-
chester ' for 1845, on " Some Microscopical Objects found in the Mud
of the Levant and other Deposits, with Remarks on the mode of
Formation of Calcareous and Infusorial Siliceous Rocks." This was
the most important of his works up to that date, and helped to lay
the foundation of our knowledge of the part played by Foraminifera
in the formation of geological deposits.
Williamson continued the study of these minute organisms, con-
firming the conclusions of Dujardin as to their affinities, and demon-
strating the great variability of the living species. Many years later,,
in 1857, he completed his monograph for the Ray Society on the
* ' Reminiscences of a Yorkshire Naturalist,' page 47.
XXIX
recent Foraminifera of Great Britain, after publishing a number of
shorter memoirs on the group.
In 1851-2 Williamson made a careful study of the organisation of
Volvox Globator, and brought out facts as to the mode of connection
between its cells, which have only been verified by other observers
within the last few years. This was probably his best contribution
to recent botany.
Shortly before this date Williamson had undertaken an investiga-
tion of a totally different kind, namely, the development of the
teeth and bones of fishes, which he considered in relation to the cell
theory. His results in this field were of great importance, and are
embodied in two papers published in the * Philosophical Transactions
of the Royal Society ' for 1849 and 1851. The value of these inves-
tigations was recognised by his election as a Fellow of the Royal
Society in 1854.
Previously to this, in January, 1851, Williamson had entered the
ranks of official teachers of Science, by his appointment as Professor
of Natural History in the newly founded Owens College at Man-
chester. This was an arduous post, for the subjects to be taught
included three sciences : zoology, botany, and geology. At first he
found it possible to deal with this formidable task, by spreading his
complete course over two years, a wise arrangement under the cir-
cumstances, but one which the exigencies of the examination system
ultimately rendered impracticable. This led in 1872 to a division of
the duties of the chair, Williamson being then relieved of the geo-
logical part of the teaching by Professor Boyd Dawkius. The remain-
ing work, however, was still far too extensive for any one teacher, and
in 1880 a further division of labour took place. The late Professor
Milnes Marshall occupied the chair of zoology, while Williamson
retained that of botany, which he continued to hold till 1892.
In addition to his strictly official work as Professor, Williamson
was one of the first two members of the staff, who, as early as 1854,
started evening classes for working men. In later years, he met
with extraordinary success as a popular scientific lecturer, more
especially for the Gilchrist Trustees, for whom he delivered some
hundreds of lectures during the period from 1874 to 1890. His
power of rousing and retaining the interest of great popular audi-
ences is described by those who have heard him as most remarkable.
During a great part of the time at Owens College, Williamson
continued in active and successful practice as a physician. In the
midst of all his multifarious duties, as professor, popular lecturer,
and medical practitioner, he always found time for original scientific
work ; rarely has so busy a man done so much for the advancement
of science by actual research.
So far, little has been said of the work of Williamson on fossil
XXX
botany, the subject with which his name is now most intimately
associated, as it occupied all the latter part of his career as an
investigator. His interest in such matters goes back, as has been
mentioned above, to the very beginning of his scientific life. In
addition to his work for Lindley and Hutton, a paper of his on the
origin of coal was read before the British Association as early as
1842. His first original contribution to fossil botany dates from the
year 1851, when he published a paper " On the Structure and
Affinities of the Plants hitherto known as Sternbergia?," in which he
demonstrated their true nature as casts of the pith-cavity of Grymno-
spermous trees. A few years later, in 1854-5, he published papers
on what was then called Zamia gigas, an extraordinary oolitic fossil,
which Williamson believed to have Cycadean affinities, a view which
has since been so far confirmed that the fossil is now regarded as
representing the fructification of one the Bennettiteas, an allied,
though very different family. Williamson's full memoir on the
subject was written soon after 1855, but, owing to a succession of
misfortunes, its appearance was long delayed, and it only saw the
light in the ' Linnean Society's Transactions ' for 1868, when it was
published simultaneously with Mr. Carruthers' well-known paper on
fossil Cycadean stems. The latter author founded a new genus for
Zamia gigas under the name of Williamsonia.
Williamson's really characteristic work in fossil botany consisted
in the investigation of the histological structure of carboniferous
plants. The first beginning was made with the paper on Sternbergia,
but it was not till long afterwards that the long series of publications
began, which have done more than the works of any other writer to
make us acquainted with the organisation of Paleozoic plants. It
was early in the fifties that Williamson made his first sections, but
not till 1868 that, in consequence of a correspondence with the
French palasobotanisfc, Grand'Eury, he published the result of his
investigations in the paper u On the Structure of the Woody Zone
of an undescribed Form of Calamite," ' Manchester Literary and
Philosophical Society's Proceedings,' Ser. 3, vol. 4. From that
period onwards, his whole time available for original research was
devoted to the Carboniferous Flora, and a magnificent series of
memoirs was the result, which will always rank among the classics
of fossil botany. The Royal Society alone published in the ' Philo-
sophical Transactions ' nineteen memoirs from his hand, their dates
ranging from 1871 to 1893, and, besides these, many valuable papers
appeared elsewhere, notably the memoir on Stigmaria ficoides, pub-
lished in 1886, by the Palseontographical Society. It is impossible
here to attempt anything like a summary of this great work, which
threw light on every department of Palaeozoic botany.*
* For fuller information see Williamson's ' Reminiscences/ especially chap. 13 ;
XXXI
Perhaps the greatest result was his demonstration, after a contro-
versy extending over a quarter of a century, that the Sigillarian and
Calamarian trees of the Carboniferous period were Cryptogams. To
use his own words : " The fight was always the same : Was Brong-
niart right or wrong, when he uttered his dogma, that if the stem of
a fossil plant contained a secondary growth of wood, the product of
a cambium layer, it could not possibly belong to the cryptogamic
division of the vegetable kingdom?" Williamson ultimately suc-
ceeded in convincing his opponents, including almost all the members
even of the French school, that the plants in question are nothing
but highly organised Cryptogams, their secondary growth being
mainly an adaptation to arborescent habit, and by no means an indi-
catioln of Phanerogamic affinities. Tn this controversy Williamson
had two sets of opponents ; namely, those who followed Brongniart
in regarding plants with secondary growth as necessarily phanero-
gamic, and those who, while recognising the cryptogamic nature
of the plants under discussion, denied or minimised the secondary
growth itself. Williamson, in spite of occasional mistakes in detail,
was ultimately victorious on both issues; there is to-day, not the
slightest doubt that most Palaaozoic Cryptogams formed, by means
of cambium, secondary tissues essentially similar to those of Dicotyle-
dons or G-ymnosperms, and that these plants were none the less as
truly cryptogamic as their less highly organised representatives at
the present day.
But, apart from this controversy, upon which it is superfluous to
dwell longer, Williamson advanced our knowledge of the ancient
plants in many directions, especially as regards the Sphenophylleaa,
of which he discovered the first fructifications showing structure ;
the fructifications of Calamarieaa and Lepidodendreoe ; the various
types of structure among the fossil Lycopods ; the existence of a
group on the frontier of Ferns and Cycads, &c. He made mistakes,
as all do, who carry out extensive investigations in a new field, but
he corrected most of them himself, and they in no way afiect the per-
manent value of his great work in laying the secure foundations of
scientific palaeozoic botany.
Williamson's remarkable skill as a draughtsman added greatly to
the value of his memoirs, which are illustrated almost wholly by his
own hand. He was by nature an artist, and, in addition to his scien-
tific drawings, painted many pleasing landscapes in water-colours
during his leisure hours.
Williamson was an all-round naturalist of a type now unhappily
all but extinct. He made his mark as a distinguished original
the obituary notice by Solms-Laubacli, in ' Nature ' for September 5, 1895 ; and
D. H. Scott, " Williamson's Eesearcb.es on the Carboniferous Flora," ' Science
Progress,' December, 1895.
XXX11
investigator in three distinct sciences ; in geology, by bis early work
on zonal distribution of the fossils on the Yorkshire coast, and again
by his investigations of the Foraminifera of marine deposits ; in
zoology, by his researches on the development of the teeth and bones,
not to mention his work on recent Foraminifera and Rotifera ; in
botany, by his elucidation of the structure of fossil plants. It would
be difficult to find another example from our own time of equally
varied and successful scientific activity.
His ability was recognised by competent men of science from his
early youth upwards, and daring all the earlier part of his career his
work was of an advanced type, and up to the best standard of the
day. At a later period, especially during his investigations of the
Carboniferous Flora, this was no longer the case in an equal degree.
Owing chiefly, perhaps, to his want of knowledge of German, his later
publications suffered somewhat from his insufficient familiarity with
the results of modern botanical work, and with the consequent tech-
nical expressions. This makes some of his writings hard to follow,
and has led to their being estimated below their true value by some
botanists of a more modern school, who have sometimes failed to
appreciate discoveries, however important, unless recorded in the
current vernacular of modern science. Those, however, who take the
trouble to surmount this initial difficulty, will always be astonished at
the wealth of observation which his work contains, and at the sound
judgment which he brought to bear on his discoveries.
After his retirement from official duties in 1892, Williamson spent
the last three years of his life near London in peaceful devotion to
his favourite studies, continuing his scientific researches to the last.
His death took place at his house at Clapham Common, on June 23,
1895, at the age of 78.
His unique collection of slides, illustrating the microscopical struc-
ture of fossil plants, has happily been acquired by the British
Museum (Natural History Department).
Williamson received various marks of public recognition during
his long career. A Royal medal was awarded to him in 1874 for his
researches on fossil plants, at a time when he had only published six
out of his nineteen memoirs in the 'Philosophical Transactions'; in
1890 he received the Wollaston medal of the Geological Society ; he
was a foreign member of the Gottingen Academy of Sciences, and of
the Royal Society of Sweden ; in 1883, the University of Edinburgh
conferred upon him the degree of LL.D.
D. H. S.
Admiral Sir GEORGE HENRY RICHARDS, K.C.B. This officer, the
son of Captain G. S. Richards, R.N., was born in 1820, and entered
the Royal Navy, on board the " Rhadamaiithus," in 1833, and served
XXX111
in her in the West Indies for two years under the late Admiral G.
Graves. In 1835 he was appointed midshipman in an expedition
consisting of the " Sulphur " and " Starling," fitting out under the
late Admiral F. W. Beechey, for exploration and survey in the Pacific.
He served for five years in the " Sulphur," chiefly under Sir Edward
Belcher, on the surveys of the West Coasts of South and North
America, the Pacific Islands, New Guinea, and the Moluccas, and was
then transferred as Senior Executive Officer to the " Starling,"
Captain Kellett. He was present in her during the first Chinese
War<kt the taking of the Bogne forts and the capture of Canton.
The ship returned to England in 1842.
After three months in the "Caledonia," under the flag of Sir
David Milne, he was, on July 12, 1842, promoted to Lieutenant, and
appointed to the " Philomel," fitting for the survey of the Falkland
Islands, under Captain Bartholomew Sulivan. The " Philomel " was,
however, diverted from this survey to take part in the operations
against Rosas, the President of the Republic of Buenos Ayres, in
1845-46. Lieutenant Richards was present at the different actions
in the Parana and the Uruguay, and commanded the boats of the
" Philomel " at the cutting out of a schooner at night under a
heavy fire of musketry from the banks of the Uruguay, and received
the thanks of the senior officer, Sir C. Hotham, on the quarter deck
of the " Gorgon."
He was senior lieutenant at the attack of the forts at Obligado
in the Parana on November 18, 1845, and commanded the small-arm
men of the " Philomel " at the storming of the batteries and cap-
ture of the guns which were taken on board the ships. On his
return to England, in June, 1846, he was promoted to Commander
from the date of the action.
In 1847 he was appointed to the "Acheron," Captain J. Lort
Stokes, destined for the survey of New Zealand, and was employed
for four years on this service. The existing charts of this colony
are mainly the result of this survey.
Returning home, in 1852, Commander Richards volunteered for,
and was immediately appointed to, an expedition fitting out for the
Arctic Regions to continue the search for the missing ships of Sir
John Franklin, and in April of that year sailed as Commander of
the " Assistance," and second to Sir Edward Belcher in the Welling-
ton Channel division of the squadron.
Whilst on this service he conducted several extended sledging
expeditions, travelling more than 2,000 miles over the frozen sea,
mapping many unknown coasts, and being absent from the ships on
such duty for a period of, on the whole, seven months. Commander
Richards' unvarying good humour and good fellowship did much to
render this expedition a success under very trying circumstances.
XXXIV
On his return to England in the autumn of 1854 he was promoted
to the rank of Captain, and was not again employed till 1856, when
he was appointed to the command of the " Plumper," in charge of
the survey of Vancouver Island and the coasts of British Columbia.
He was at the same time nominated a Queen's Commissioner con-
jointly with Captain Prevost, R.N., for settling the Oregon boundary
question between Great Britain and the United States.
Captain Richards settled the point on the coast from which the
boundary line should start, and rendered efficient aid to the com-
bined party of Royal Engineers and others who traced it to the east-
ward.
In the " Plumper," and subsequently in the " Hecate," he con-
ducted for seven years the surveys of the intricate and rock- studded
coasts and channels of Vancouver and British Columbia, accom-
plishing a marvellous amount of work. He returned to England in
1863 by the islands of the Western Pacific, Australia, and Torres
Straits, making surveys and fixing longitudes on the way. This
voyage completed his third circumnavigation of the globe.
He arrived in England to find himself appointed Hydrographer of
the Admiralty, the late occupant of the post. Admiral Washington,
having recently died.
Captain Richards held this post for 10 years, and by his powers of
organisation, and the most unremitting industry, greatly increased
the efficiency of his department, which he administered with great
skill, and placed upon a firm basis to meet its ever growing work.
A new scheme of retirement placed Richards, who had attained
the rank of Rear- Admiral on June 2, 1870, on the retired list in
1874, when he left the Admiralty.
Whilst Hydrographer he did all in his power to further scientific
exploration of the sea. The preliminary voyages made by Dr.
Carpenter, Mr. Gwyn Jeffreys, and Dr. Wyville Thomson in the
" Porcupine," " Lightning," and other of H.M. surveying vessels in
1868-71 were promoted by him, and led up to the ever memorable
expedition of the " Challenger " in 1872, in the inception of which he
played a very important part, whilst its fitting out and organisation
were carried out under his superintendence.
He also made the preliminary arrangements for the transport
of the expeditions for the observation of the Transit of Venus in
1874, which were carried out shortly after he relinquished office.
In 1866 Richards was elected a Fellow of the Royal Society, and
in the same year a Corresponding Member of the Academy of
Sciences of Paris. He was also an active member of the Royal
Geographical Society, serving on the Council.
In 1869 he was nominated an A.D.C. to the Queen, and in 1871 a
Companion of the Bath. He received the honour of knighthood in
XXXV
1877, and in 1888 the Knight Commandership of the Military Divi-
sion of the Bath.
Admiral Richards was, while serving at the Admiralty and sub-
sequently, a trusted adviser of several administrations, and was a
member of several committees on confidential and general subjects,
and was also President of the Arctic Committee which sat in 1875.
He became a Vice-Admiral in 1877, and Admiral in 1884.
After leaving the Admiralty he was at once offered and accepted
the position of Managing Director of the Telegraph Construction
and Maintenance Company, which he held for twenty years, when he
was elected Chairman of the Company, a post he occupied to his
death.
Whilst Managing Director, some 76,000 miles of submarine
cables were laid under his superintendence in different parts of the
world.
He was also Acting Conservator of the Mersey from the year 1888,
an important post in connection with the well-being of that great
seaport.
Sir George Richards served several times on the Council of the
Royal Society, and was nominated a Yice-President.
He was a man of great ability, of sound common-sense, and of un-
tiring activity, and his unfailing good humour, general shrewdness,
and kindness to younger members of his profession caused him to be
universally beloved and respected.
He died at Bath on November 14, 1896, somewhat suddenly, though
after a painful period of severe sciatica.
Sir G. Richards married, first, in 1847, Mary, a daughter of Cap-
tain R. Young, R.E., by whom he had several sons and daughters ;
and, secondly, Alice Mary, daughter of the Rev. R. S. Tabor, of
Cheam, who survives him.
W. J. L. W.
INDEX TO VOL. LX.
Abney (W. de W.) Xote en Photographing Sources of Light with Monochromatic
Rays, 13.
and Thorpe (T. E.) On the Determination of the Photometric Intensity
of the Coronal Light during the Solar Eclipse of 16th April, 1893, 15.
Address of the President, 299.
Adiabatic Relations of Ethyl Oxide (Perman, Ramsay, and Rose-limes), 336.
Air, Liquid, Dielectric Constants of, 358 ; Magnetic Permeability of (Fleming and
Dewar), 283.
Alloys, Freezing-point Curves of Silver and Copper, determined by Platinum
Resistance Thermometer (Hey cock and Neville), 160.
of Gold, Annealing at Moderate Temperatures, Mechanical Properties of
(Osmond and Roberts-Austen), 148.
— : Liquation of certain (Matthey), 21.
Anguilla vulgaris, Bridal habit of, 269 ; Development of, from Leptocephalus
brevirostris, 2(30; Matures in Deep Sea, 262; Peculiar forms of, in the Roman
Cloacae (G-rassi), 270.
Annealing Alloys of Gold (Osmoiid and Roberts- Austen), 148.
Anniversary Meeting, 296.
Apogamy in Scolopendrium vulgare, L, and Aspidium frondosum, Lowe (Lang),
250.
Argon, Electric Arc between Carbons in, 53 ; Fractional Diffusion of, 206 ;
Inactivity of, towards Elements, &c., at High Temperatures (Ramsay and
Collie), 53.
in the gas from the Bath Springs (Rayleigh), 56.
Asconidee, Development of (Minchin), 60.
Assheton (R.) An Experimental Examination into the Growth of the Blastoderm
of the Chick, 349.
Atomic Volume, Influence of, in Relation to Gold Alloys (Osmond and Roberts-
Austen), 148.
Auditors, Report of, 296.
Baden-Powell (Sir G.) Total Eclipse of the Sun, 1896. The Xoraya Zemlya
Observations, 271.
Baily (F. G.) The Hysteresis of Iron and Steel in a Rotating Magnetic Field,
182.
Basalt, Gases contained in (Tilden), 453.
Bath Springs, Gases from— Argon and Helium in (Rayleigh), 56.
Benham's Artificial Spectrum Top (Bidwell), 368.
Bessemer Flame Spectra, Gallium in (Hartley and Raniage), 35.
Bidwell (S.) On Subjective Colour Phenomena attending Sudden Changes of
Illumination, 368.
Bismuth, Electrical Resistivity of, at Low Temperatures and in Magnetic Fields,
425 ; Electrical Resistivity of, at the Temperature of Liquid Air (Dewar and
Fleming), 72.
VOL. LX. J7
XXXV111
Bismuth, Experiments on the Electrical Resistance of (Fleming and Dewar), 6.
Blastoderm of the Chick, An Experimental Examination into the Growth of the
(Assheton), 349.
Bose (J. C.) On the Determination of the Wave-length of Electric Radiation by
Diffraction Orating, 167.
On the Selective Conductivity exhibited by certain Polarising Substances, 433.
Burch (Q-. J.) On Professor Hermann's Theory of the Capillary Electrometer,
329.
and G-otch (F.) The Electromotive Properties of the Electrical Organ of
Malaptertirus electricus, 37.
Candidates recommended for Election, 2.
Carbon Dioxide and Water Vapour decomposed by Ferrous Acid (Tilden), 453.
Carbonic Acid, origin of Terrestrial (Moissan), 156.
Carboniferous Batrachians exhibited by Sir J. Dawson, 6.
Carbonyl-oxygen, Influence of, on Yiscosity (Thorpe and Rodger), 152.
Carbures Metalliques, Etude des (Moissan), 156.
Carcinus onoenas, Changes in relative Dimensions of (Thompson), 195.
Cathode Rays, Effects of Magnetic Field on (Swinton), 179.
Cerebellum, Phenomena resulting from Interruption of Afferent and Efferent Tracts
of, (Russell), 199.
Cerebral Hemispheres, Distribution of Tonic Rigidity developed after removal of,
414; Effects of Removal upon Reflex Movements (Sherrington), 411.
Vheirostrobus, On, a new Type of Fossil Cone from the Calciferous Sandstones
(Scott), 417.
Chree (C.) Observations on Atmospheric Electricity at the Kew Observatory, 96.
Clarke (Sir George Sydenham) elected, 4 ; admitted, 6.
Clay Ironstone, Occurrence of Gallium in (Hartley and Ramage), 393.
Collie (J. Norman) elected, 4 ; admitted, 5.
and Ramsay (W.) Helium and Argon. Part III. Experiments which
show the Inactivity of these Elements, 53 ; The Homogeneity of Helium and
Argon, 206.
Colour Phenomena attending Sudden Changes of Illumination (Bidwell), 368.
Colours (Monochromatic), Plan for obtaining Images of different (Abney), 33.
Conductivity, Selective, exhibited by Polarising Substances (Bose), 433.
Coral Atoll (Funafuti), Account of Attempt to investigate the Structure of a,
by Boring (Sollas), 502.
Growth, Bathymetrical Limit of (Sollas), 502.
Coronal Light, Determination of the Photometric Intensity of the, during the
Eclipse of 16th April, 1893 (Abney and Thorpe), 15.
Correlation between Parent and Offspring, 273 ; of Indices, Organic and Spurious,
of long Bones, of parts of Skull (Pearson), 489.
Skew, Significance of Normal Formulae in (Yule), 477.
Spurious (Galton), 498.
Variations in Portunus depurator (Warren), 221.
Council, Election of, 316.
Crystallisation of Alloyed Gold (Osmond and Roberts-Austen), 148.
Cutting Edge, Radius of Curvature of a (Mallock), 164.
Cyanogen, Spectrum of (Hartley), 216.
Dawson, Sir J., Carboniferous Batrachians exhibited by, 6.
Detector, Magnetic, of Electrical Waves (Rutherford), 184.
XXXIX
Dewar (J.) and Fleming (J. A.) Changes produced in Magnetised Iron and Steels
by Cooling to the Temperature of Liquid Air, 57.
Experiments on the Electrical Resistance of Bismuth, 6.
— On the ^lectrical Resistivity of Bismuth at the Temperature of Liquid
Air. 72 ; On^ttie Electrical Resistivity of Bismuth at Low Temperatures and
in Magnetic Wields, 425.
On the Electrical Resistivity of Pure Mercury at the Temperature of
Liquid Air, 76.
— On the Magnetic Permeability and Hysteresis of Iron at Low Tempera-
tures, 81.
On the Magnetic Permeability of Liquid Oxygen and Liquid Air, 283.
The Dielectric Constants of Liquid Oxygen and Liquid Air, 358.
Dielectric Constants of Liquid Oxygen and Liquid Air (Fleming and Dewar), 358.
Dielectrics, Capacity, &c., of, as affected by Temperature and Time (Hopkinson and
Wilson), 425.
Diffusion of Helium and Argon (Ramsay and Collie), 206.
Donation Fund, Grants from, 328.
Downing (Arthur Matthew Weld) elected, 4; admitted, 5.
Earthquake Frequency and Lunar Periodicity (Knott), 457.
Eclipse of the Sun, April 16, 1893. Observations relating to Solar Physics
(Lockyer), 17.
On the Photometric Intensity of the Coronal Light during the
(Abuey and Thorpe), 15.
in 1896, Preliminary Report on Results with Prismatic Camera (Lockyer),
270.
Novaya Zemlya Observations (Baden -Powell), 271.
Eden (T. W.) The Occurrence of Nutritive Fat in the Human Placenta. Pre-
liminary Communication, 40.
Eel, Reproduction and Metamorphosis of the Common (Grassi), 260.
Electric Arc at various pressures in Air, CO2, &c.. ; Evaporation rate in Mercury
and Carbon Craters ; Mercury Crater Temperature (Wilson and Fitzgerald) ,
377.
Discharges in Vacuo, Effects of Magnetic Field upon (Swinton), 179.
Spectrum, produced by Grating, Linear nature of (Bose), 167.
Electrical Conductivity and Anisotropic Absorption of Electro-Magnetic Radiation,
Relation between (Bose), 433.
Discharges of High Frequency, Detection and Measurement of, by Magnetised
Steel Needles (Rutherford), 184.
Organ of Malapterurus electricus, Electromotive Properties of (Gotch and
Burch), 37.
— Resistance of Bismuth, Experiments on the (Fleming and Dewar), 6.
Resistivity of Bismuth at the Temperature of Liquid Air (Dewar and
Fleming), 72.
of Pure Mercury, at the Temperature of Liquid Air (Dewar and Fleming),
76.
Electricity, Atmospheric, Observations at Kew Observatory (Chree), 96.
Electrograph, Action of, in the interpretation of Records (Chree), 96:
Electro-Magnetic Radiation, Polarisation of by Nemalite, Chrysotile, Fibrous
Gypsum, and Epidote (Bose), 433.
Electrometer, Capillary, Theory of the (Burch), 329.
Electrotonic Currents of Nerve, Influence of Temperature upon (Waller), 383.
xl
Elgar (Francis) elected, 4 ; admitted, 260.
Eliot (John) admitted, 424.
Esters, Viscosity of (Thorpe and Rodger), 152.
Ether-oxygen, Influence of, on Viscosity (Thorpe andjRodger), 152.
Ethers,Viscosity of (Thorpe and Kodgor), 152.
Ethyl Oxide, Adiabatic Relations of (Perman, Ramsay, and Rose-Innes), 336.
Ethylbenzene, Viscosity of (Thorpe and Rodger), 152.
Evans (Sir J.) On some Palaeolithic Implements found in Somaliland by H. W..
Seton-Karr, 19.
Evolution, Mathematical Contributions to the Theory of '(Pearson), 273, 489.
Farmer (J. B.) and Williams (J. L.) On Fertilisation, and the Segmentation of
the Spore in Fucus, 188.
Fat, Nutritive, in Human Placenta (Eden), 40.
Fats, Absorption from Intestine ; Solubility of, in Intestinal Fluid; Simultaneous-
Action of Pancreas and Bile on (Moore and Rockwood), 438.
Fellows admitted, 1, 5, 6, 260, 424; deceased, 296; elected, 4; number of, 328.
Fern Prothalli, Development of Sporangia upon (Lang), 250.
Financial Statement, 317.
Fitzgerald (G. F.) and Wilson (W. E.) On the Effect of Pressure in the
Surrounding Gas on the Temperature of the Crater of an Electric Arc..
Correction of Results in former Paper, 377.
Fleming (J. A.) and Dewar (J.) Changes produced in Magnetised Iron and
Steel by Cooling to the Temperature of Liquid Air, 57.
Experiments on the Electrical Resistance of Bismuth, 6.
On the Electrical Resistivity of Bismuth at the Temperature of Liquid1
Air, 72 ; the Electrical Resistivity of Bismuth at Low Temperatures and in
Magnetic Fields, 425.
On the Electrical Resistivity of Pure Mercury at the Temperature of
Liquid Air, 76.
On the Magnetic Permeability and Hysteresis of Iron at low Tempera-
tures, 81.
On the Magnetic Permeability of Liquid Oxygen and Liquid Air, 283.
The Dielectric Constants of Liquid Oxygen and Liquid Air, 358.
Foetus, Human, Nutrition of (Eden), 40.
Foreign Members, Election of, 328.
Fossil Cone from Calciferous Sandstones (Scott), 417.
Freezing Point Curves of Silver and Copper Alloys, determined by Platinum
Resistance Thermometer (Hey cock and Neville), 160.
Determinations of Thermometers, Errors of j Methods in use for ; New
Apparatus for (Harker), 154.
Fucus, Fertilisation and Segmentation of the Spores in Species of (Farmer and
Williams), 188.
Gallium in Cleveland Clay -Ironstone, Determination in Blast-furnace Metal
(Hartley and Ramage), 393.
in Cleveland Iron Ore and Middlesborough Iron (Hartley and Ramage), 35,
Galton (F.) Note to the Memoir, by K. Pearson, on Spurious Correlation, 498.
Galvanometer, a Delicate, for use with Platinum Thermometers (Harker), 154.
Gases, Analysis of, by Refractivity (Rayleigh), 56.
enclosed in Rocks and Minerals (Tilden) , 453.
in Mineral Substances and Natural Waters (Rnmsay and Travers), 442.
xli
•Gladstone (J. H.) The relation between the Refraction of the Elements and their
Chemical Equivalents, 140.
•Gneiss, Basalt, and Granite, Composition of Gases enclosed in (Tilden), 453.
Gold, Alloyed, Effect of Annealing, 148 ; Micro-structure of (Osmond and
Roberts- Austen) , 148.
Liquation of certain Alloys of (Matthey), 21.
Gorst (Sir John) elected a Fellow, 357 ; admitted, 408.
Gotch (F.) and Burch (G. J.) The Electromotive Properties of the Electrical
Organ of Malapterurus etectricus, 37.
Granite, Gneiss, and Basalt, Composition of Gases enclosed in (Tilden), 453.
Grassi (G. B.) The Reproduction and Metamorphosis of the Common Eel
(Anguilla vulgaris), 260.
Gray (Andrew) elected, 4 ; admitted, 5.
Harker (J. A.) On the Determination of Freezing Points, 154.
Hartley (W. IS".) On the Spectrum of Cyanogen, as produced and modified by
Spark Discharges, 216.
and Ramage (H.) On the Occurrence of Gallium in the Clay -Iron stone of
the Cleveland District of Yorkshire. Determination of Gallium in Blast-
furnace Iron from Middlesborough, 393.
on the Occurrence of the Element Gallium in the Clay -Iron stone of the
Cleveland District of Yorkshire. Preliminary Notice, 35.
Heape (W.) The Menstruation and Ovulation of Macacus rhesus, 202.
Heim (Albert), elected a Foreign Member, 328.
Helium, Experiments on (Travers), 449.
Fractional Diffusion of, 206 ; Inactivity of, towards Elements, &c., at High
Temperatures (Ramsay and Collie), 53.
Occurrence in Minerals, Natural Waters, and Meteorites (Ramsay and
Travers), 442.
Heredity, Coefficients of, in Man (Pearson), 273.
Hermann's Theory of Capillary Electrometer (Burch), 329.
Heycock (C. T.) and Neville (F. H.) Complete Freezing Point Curves of Binary
Alloys containing Silver or Copper, together with another Metal, 160.
Hinde (George Jennings) elected, 4 ; admitted, 5.
Hodgson (Brian H.), Obituary Notice of, xxiii.
Hopkinson (J.) and Wilson (E.) On the Capacity and Residual Charge of
Dielectrics as affected by Temperature and Time, 425.
Hydrocarbons formed by Action of Water on Metallic Carbides (Moissan), 156.
— Production of, beneath the Earth's Crust (Tilden), 453.
Hydrogen and Carbonic Oxide in Rocks and Minerals (Tilden), 453.
Hydroxyl-oxygen, Influence of, on Viscosity (Thorpe and Rodger), 152.
Hysteresis in Rotating Magnetic Field, Verification of law of, Effect of speed of
rotation on, and unstable values of, at critical point (Baily), 182.
of Iron at Low Temperatures (Fleming and Dewar), 81.
Income and Expenditure Account, 327.
Indices, Spurious Correlation of (Pearson), 489.
Indium in Manganiferous Iron Ore (Hartley and Ramage), 393.
Innervation, Reciprocal, of Antagonistic Muscles (Sherrington), 414.
Intestine, Absorption of Fats from (Moore and Rock wood), 438.
Iron, Magnetic Permeability and Hysteresis of, at Low Temperatures (Fleming
and Dewar), 81.
xlii
Iron, Spectrum of, at High Temperatures (Lockyer), 475.
and Steel, Hysteresis of (Baily), 182.
Magnetic. Changes in, when Cooled to Temperature of Liquid Air
(Dewar and Fleming), 57.
Isopentane, Viscosity of (Thorpe and Eodger), 152.
Japan Earthquakes, Frequencies of, analysed harmonically (Knott), 457.
Johnson (Sir George), Obituary Notice of, xvi.
Kelvin (Lord), Address to, on Occasion of Professorial Jubilee, 5.
Kennedy (R.) On the Regeneration of Nerves, 472.
Kew Observatory, Observations on Atmospheric Electricity (Chree), 96.
Knott (C. G-.) On Lunar Periodicities in Earthquake Frequency, 457.
Kopp (Hermann), Obituary Notice of, i.
Lang (W. H.) Preliminary Statement on the Development of Sporangia, upon
Fern Prothalli, 250.
Larmor (J.) The Influence of a Magnetic Field on Radiation Frequency, 514.
and Lodge (J.), announce a Discovery by P. Zeeman, 466.
Lastrcea dilatata, Presl., Sporangia on Prothalli of, 250.
Leptocephalus, Species of, and related Adult Mursenida3 (Orassi), 260.
Leucosolenia variabilis, H., sp., Note on the Larva and Postlarval Development of
(Minchin), 42.
Light, Influence of Magnetic Field on Eadiation Frequency (Lodge), 513.
(Larmor), 514.
Lippmann (Grabriel), elected a Foreign Member, 328.
On Colour Photography by the Interferential Method, 10.
Liquation of certain Alloys of G-old (Matthey), 21.
Liquids, Magnetisation of (Townsend), 186.
Relations between Viscosity and Chemical Nature of (Thorpe and Rodger),.
152.
Lockyer (J. N.) On the Iron Lines present in the Hottest Stars. Preliminary
Note, 475.
Preliminary Report on the Results obtained with the Prismatic Camera
during the Eclipse of 1896, 270.
The Total Eclipse of the Sun, April 16, 1893. Report and Discussion of
the Observations relating to Solar Physics, 17.
Lodge (O.) The Influence of a Magnetic Field on Radiation Frequency, 513.
• and Larmor (J.), announce a Discovery by P. Zeeman, 466.
Macacus rhesus, The Menstruation and Ovulation of (Heape), 202.
M'Clelland (J. A.) Selective Absorption of Rontgen Rays, 146.
Magnetic Field, Effect on Emission and Absorption of Light (Larmor). 514.
Effect on Emission and Absorption of Light (Lodge), 513.
Fields, Effect of, on Bismuth at Low Temperatures (Dewar and Fleming),
425.
Moment of Magnets of various kinds of Iron and Steel at very low Tempera-
tures (Dewar and Fleming), 57.
— — Permeability and Hysteresis of Iron at Low Temperatures (Fleming and
Dewar), 81.
Magnetic Permeability of Liquid Oxygen and Liquid Air (Fleming and Dewar),.
283.
Magnetisation of Iron, Effect of High Frequency Discharges on (Rutherford), 184.
of Solutions of Iron Salts, Investigation of absolute value of coefficient, &c.
(Townsend), 186.
Magnetised Iron and Steel, Changes produced in, by cooling to the Temperature of
Liquid Air (Dewar and Fleming), 57.
Magnetism, Molecular theory of, law of variation of Hysteresis thence deduced
(Baily), 182.
Malapterurus electricus, Electrical Organ of (Crotch and Burch), 37.
Mallock (A.) Note on the Radius of Curvature of a Cutting Edge, 164.
Martin (Henry Newall), Obituary Notice of, xx.
Matthey (E.) On the Liquation of certain Alloys of Gold, 21.
May (W. P.) Investigations into the Segmental Representation of Movement in
the Lumbar Region of the Mammalian Spinal Cord, 244.
Medals, Presentation of the, 309.
Menstruation and Ovulation of Macacus rhesus, the (Heape), 202.
Mercury, Resistivity of, at the Temperature of Liquid Air (Dewar and Fleming),
76.
Metals, Origin of Structure in (Osmond and Roberts- Austen), 148.
Refractive Constant of Equivalent Weights (Gfladstoue), 140.
Meteorites tested for Helium (Ramsay and Travers), 442.
Miers (Henry Alexander) elected, 4 ; admitted, 6.
Minchin (E. A.) Note on the Larva and the Postlarval Development of Leucoso-
lenia varlabilis, H., sp., with Remarks on the Development of other Asconidae,
42.
Minerals, Gfascous Constituents of (Ramsay and Travers), 442.
Gfases enclosed in (Tilden), 453.
Unknown Lines in Spectra of (Lockyer), 133.
Mittag-Leffler (G-ustav), elected a Foreign Member, 328.
Moissan (H.) Etude des Carbures Metalliques, 156.
Monochromatic Images of a Source of Light (Abney), 13.
Moore (B.) and Rockwood (D. P.) On the Condition in which Fats are absorbed
from the Intestine, 438.
Mott (Frederick Walker) elected, 4 ; admitted, 5.
Murray (John) elected, 4 ; admitted, 272.
Muscle, Use of Capillary Electrometer in investigating Electrical Phenomena of
(Burch), 329.
Muscles, On Reciprocal Innervation of Antagonistic (Sherrington), 414.
Nautilus, Discovery of the Ova of, 437.
Nautilus macromphalus, The Oviposition of (Willey), 467.
Nernst's Theory of Freezing Points (Harker), 154.
Nerve, Influence of Alterations of Temperature upon the Electrotonic currents of
Medullated (Waller), 383.
Nerves, On the Regeneration of (Kennedy), 472. ^
Spinal, Peripheral Distribution of the Fibres of the Posterior Roots of some
(Sherrington), 408.
Neumann (Franz Ernst), Obituai-y Notice of, viii.
Neville (F. H.) and Heycock (C. T.) Complete Freezing Point Curves of Binary
Alloys containing Silver or Copper, together with another Metal, 160.
Nitric Oxide, produced by Electric Arc (Wilson and Fitzgerald), 377.
Nuclear Division in Oogonia, Spores and Thallus of Species of Fucus (Farmer and
Williams), 188.
xliv
Obituary Notices of Fellows deceased: — Hodgson (Brian Houghton), xxiii; John-
son (Sir G-eorge), xvi ; Kopp (Hermann),!; Martin (Henry Newall), xx ;
Neumann (Franz Ernst), viii; Prestwich (Sir Joseph), xii; Eae (John), T ;
Richards (Sir G-eorge Henry), xxxii; Williamson (William Crawford), xxvii.
Officers, Election of, 316.
Optic Axial Emergences, Angular Measurement of (Pope), 7.
QriTiagoriscus mola as a Source of Leptocephalus (Gra&si), 263.
Osmond (F.) and Roberts-Austen (W. C.) On the Structure of Metals, its Origin
and Changes, 148.
Oxygen, Liquid, Dielectric Constants of, 358 ; Magnetic Permeability of (Fleming
and Dewar), 283.
Paleolithic Implements from Somaliland (Evans), 19.
Pearson (Karl) elected, 4 ; admitted, 272.
Contributions to the Mathematical Theory of Evolution. On Telegony in
Man, &c., 273 ; Mathematical Contributions to the Theory of Evolution. On
a Form of Spurious Correlation which may arise when Indices are used in
the Measurement of Organs, 489.
Perman (E. P.), Ramsay (W.), and Rose-Innes (J.) An Attempt to Determine
the A diabatic Relations of Ethyl Oxide, 336- *
Petroleum, Possible Origin of (Moissan), 156.
Photography, Colour, by the Interferential Method (Lippmann), 10.
• of Monochromatic Images (Abney), 13.
Physiological and Chemical Reactions of Synthesised Proteid-like Substances
(Pickering), 337.
Pickering (J. W.) The Chemical and Physiological Reactions of certain Synthe-
sised Proteid-like Substances. Preliminary Communication, 337.
Placenta, Human, The Occurrence of Nutritive Fat in (Eden), 40.
Platinum Thermometer and Bridge to measure '0001 deg. (Harker), 154.
Polarisation of Liquid Electrodes (Burch), 329.
produced by Anisotropic Conducting Structures (Bose), 433.
Pope (W. J.) Angular Measurement of Optic Axial Emergences, 7.
Portunus depurator, Statistics of Correlated Variations in (Warren), 221.
President, Address of the, 299 ; Congratulations of Society* offered to, 424.
Prestwich (Sir Joseph), Obituary Notice of, xii.
Prismatic Camera, Results obtained with, in Eclipse, 1896 (Lockyer), 271.
Proteid-like substances, The Chemical and Physiological Reactions of certain Syn-
thesised (Pickering), 337.
Protoplasm in cells of Fucus, structure of (Farmer and Williams), 188.
Radiation, Electric, Wave-length of (Bose), 167.
Rae (John), Obituary Notice of, v.
Ramage (H.) and Hartley (W. N.) Occurrence of Grallium in the Clay-ironstone
of the Cleveland District of Yorkshire. Determination of Grallium 111 Blast-
furnace Iron from Middlesborough,£393.
On the occurrence of the Element Grallium in the Clay-ironstone of the
Cleveland District of Yorkshire. Preliminary Notice, 35.
Ramsay (W.) and Collie (J. N.) Helium and Argon. *Part III. Experiments
which show the Inactivity of these Elements, 53.
• The Homogeneity of Helium and Argon, 206.
Perman (E. P.), and Rose-Innes (J.) An Attempt to determine the Adi
abatic Relations of Ethyl Oxide, 336.
xly
Ramsay (W.) and Travers (M. W.) The Gaseous Constituents of certain Mineral
Substances and Natural Waters, 442.
Rayleigh (Lord). On the Amount of Argon and Helium contained in the Ga*
from the Bath Springs, 56.
Eeflexes in the Monkey, Cataleptoid (Sherrington), 411.
Eef'raction of Electric Radiations, Relation between Index of, and the Wave-length
(Bose), 167.
of Optic Axes, Measurement of (Pope), 7.
of the Elements, and their Chemical Equivalents, the Relation between the
(Gladstone), 140.
Refractivity, Analysis of Gases based on (Rayleigh), 56.
Regression Coefficients (Bravais' Formula?), Significance of (Yule), 447.
Resistivity, Electrical, of Bismuth at Low Temperatures and in Magnetic Fields
(Dewar and Fleming), 425.
Richards (Sir George Henry), Obituary Notice of, xxxii.
Roberts-Austen (W. C.) and Osmond (F.) On the Structure of Metals, its Origin
and Changes, 148.
Rockwood (D. P.) and Moore (B.) On the Condition in which Fats are absorbed
from the Intestine, 438.
Rodger (J. W.) and Thorpe (T. E.) On the Relations between the Viscosity
(Internal Friction) of Liquids and their Chemical Nature. Part II, 152.
Rontgen Rays, Selective Absorption of (M'Clelland), 146.
Rose-Innes (J.), Pernian (E. P.), and Ramsay (W.) An Attempt to determine the
Adiabatic Relations of Ethyl Oxide, 336.
Rubidium in Blast-furnace Flue-dust (Hartley and Ramage), 393.
Russell (J. S. R.) Phenomena resulting from Interruption of Afferent and Efferent
Tracts of the Cerebellum, 199.
Rutherford (E.) A Magnetic Detector of Electrical Waves, and some of its Appli-
cations, 184.
Sehiaparelli (Giovanni), elected a Foreign Member, 328.
Seolopendi'ium vulgare, L., Sporangia on Prothalli of, 250.
Scott (D. H.) On Cheirostrobus, a new Type of Fossil Cone from the Calciferol^
Sandstones, 417.
Seton-Karr, H. W., Palaeolithic Implements found in Somaliland by (Evans), 19.
Sherrington (C. S.) Cataleptoid Reflexes in the Monkey, 411.
Experiments in Examination of the Peripheral Distribution of the Fibres of
the Posterior Roots of some Spinal Nerves. Part II, 408.
On Reciprocal Innervation of Antagonistic Muscles. 3rd Note, 414.
Skew Probability, Application of Theory to Animal Statistics (Warren), 221.
Solar Atmosphere, Absorption by Gas Currents in (Wilson and Fitzgerald), 377.
Physics, Observations relating to, during Eclipse of April 16, 1893 (Lockyer),
17.
Sollas (W. J.) Report to the Committee of the Royal Society appointed to investi-
gate the Structure of a Coral Reef by Boring, 502.
Somaliland, Palaeolithic Implements from. (Evans), 19.
Spectra of Constituents exhibited by Burning Compounds (Hartley), 216.
of Minerals, Unknown Lines in (Lockyer), 133.
Spectroscopic Analysis of Blast-furnace Iron, Cinder, &c. (Hartley and Ramage),
393.
Spectrum of Cyanogen, Production of, under various circumstances (Hartley),
216.
xlvi
Spectrum Lines, Widening, &c., in Magnetic Field (Larmor), 514.
Widening, &c., in Magnetic Field (Lodge), 513.
Top, Benham's Artificial (Bidwell), 368.
Splienophyllum, Affinities with Cheirostrobus (Scott), 417.
Spinal Cord and Roots, Effects of Excitation, in Lumbar Kegion, of Mammalian
(May), 244.
•Sponges, Calcareous, Primitive Larva of (Minchin), 42.
Sporangia on Prothalli of Lastrcea dilatata, Presl., and Scolopendrium vulgare, L.
(Lang), 250.
Stars, Indications of Iron in Spectra of Hottest (Lockyer), 475.
Stature, Inheritance of (Pearson), 273.
Stebbing (Thomas Eoscoe Rede) elected, 4 ; admitted, 5.'
.Steels, Changes produced in Magnetised, by Cooling to the Temperature of Liquid
Air (Dewar and Fleming), 57.
Stewart (Charles) elected, 4 ; admitted, 5.
•Stirling (Edward Charles) admitted, 424.
Sun, Eclipse of, April 16, 1893. Observations relating to Solar Physics
(Lockyer), 17.
On the Photometric Intensity of the Coronal Light during the
(Abney and Thorpe), 15.
- in 1896, Preliminary Report on Results with Prismatic Camera
(Lockyer), 270.
in 1896, Novaya Zemtya Observations (Baden-Powell), 271.
•Swinton (A. A. C.) The Effects of a Strong Magnetic Field upon Electric Dis-
charges in Vacuo, 179.
Telegony, in Stature of Man (Pearson), 273.
Temple (Sir Richard) admitted, 1.
Thermodynamics, Application to Boiling Carbon (Wilson and Fitzgerald), 377.
Thompson (H.) On certain Changes observed in the Dimensions of Parts of the
Carapace of Carcinus mcenas, 195.
Thorpe (T. E.) and Abney (W. de W.) On the Determination of the Photometric
Intensity of the Coronal Light during the Solar Eclipse of 16th April, 1893, 15.
and Rodger (J. W.) On the Relations between the Viscosity (Internal
Friction) of Liquids and their Chemical Nature. Part II, 152.
Tilden (W. A.) Gases enclosed in Crystalline Rocks and Minerals, 453.
Townsend (J. S.) Magnetisation of Liquids, 186.
Tracheides in the Gametophyte, Morphological Significance of (Lang), 250.
Travers (M. W.) Some Experiments on Helium, 449.
and Ramsay (W.) The Gaseous Constituents of certain Mineral Substances
and Natural Waters, 442.
Trust Funds, 319.
Vacuum Tubes in a Magnetic Field, Experiments with (Swinton), 179.
Variation, Parental and Filial (Pearson), 273.
in Portunus depurator, Statistics of (Warren), 221.
Variation in parts of Carapace of Carcinus moenas (Thompson), 195.
Vice-Presidents, Appointment of, 329.
Viscosity of Liquids (Thorpe and Rodger), 152.
Waller (A. D.) Influence of Alterations of Temperature upon the Electrotonic
Currents of Medullated Nerve, 383.
xlvii
Warren (E.) Variation in Portunus depiirator, 221.
Water, Bath spring, Amount of Argon and Helium in (Rayleigh), 56.
Waters, Mineral, examined for Helium (Ramsay and Travers), 442.
Willey (A.) His Discovery of the Ova of Nautilus, 437.
The Oviposition of Nautilus macromphalus, 467.
Williams (J. L.) and Farmer (J. B.) On Fertilisation, and the Segmentation of
the Spore in Fucus, 188.
Williamson (William Crawford) Obituary Notice of, xxvii.
Wilson (William E.) elected, 4; admitted, 5.
and Fitzgerald (Q-. F.) On the Effect of Pressure in the Surrounding Gas on
the Temperature of the Crater of an Electric Arc. Correction of Results in
former Paper, 377.
Woodward (Horace Bolingbroke) elected, 4 ; admitted, 5.
Wynne (William Palmer) elected, 4 ; admitted, 5.
Yule (G-. U.) On the Significance of Bravais' Formulae for Regression, &e., in the-
case of Skew Correlation, 477.
Zeeman's discovery of Effect of Magnetic Field on Radiation Frequency (Lodge)
513.
ERRATUM.
P. 313, line 23. For Philip P. Lenard, read Philipp Lenard.
THE END.
HAKRISOS AND SONS, PBINTEM IK OBDWAHY TO HEE MAJEST1', ST. MABTIS'S LA>E.
BtNDIN
OCT1
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