Skip to main content

Full text of "Proceedings of the Royal Society of London"

See other formats


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

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

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

Usage guidelines 

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

We also ask that you: 

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

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

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

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

About Google Book Search 

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



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



^ 



tW^JT 




m 



► 





PROCEEDINGS 



OF THE 



>TAL SOCIETY OF LONDON. 



From January 17, to June 20, 1901. 



VOL. LXVIIL. 



LONDON: 
HARRISON AND SONS, ST. MARtnt!S LANE, 
gdnitri in •tbhiMii <> 9>* 9<4**>S'; 

September, 1901. 



LOKDoir : 

RASBIBOV AKD 80VS, PBIKTBBS IS OBDIHABT TO HX8 MAJB8TT, 
****• 8T. XARTIV'8 ULVB. 

• • • 

':;;i 112691 

• • • •• ••* 

«- - • • • • • • 

^ • •• •«••• 
:-••• ;•••• 

•••• • •• ••». 

••••• ••;. •• 

••••• .• ••••• 

• •. •/•'• • • • 

• • • • • •« • • 



•»" •• •••• 

• •»••• ••• 

• • • • • • • • ' • 

•#•*• •••• ' '• 

* ••••• ••••• 

.•• ••••• ••••• 

• • • 

••••• 

• • •• 



CONTENTS. 
VOL. LXVIII. 



o:«t:o* — 



Page 
1 



No. 442. 

Meeting of January 17, 1901, and Proceedings 

Mathematical Contributions to the Theory of Evolution. IX. — On the 
Principle of Homotyj)oeis and its Relation to Heredity, to the Vari- 
ability of the Individual, and to that of the Eace. Part I.— 
Homotyposis in the Vegetable Kingdom. By Karl Pearson, F.R.S., 
with the assistance of iJice Lee, D.Sc, Ernest Warren, D.Sc, Agnes 
Fry, Cicely D. Fawcett, B.Sc., and others « 1 

Total Eclipse of the Sun, January 22, 1898. Observations at Vizia- 
drug. Part IV.— The Prismatic Cameras. By Sir Norman Lockyer, 
K.C.R, F.R.S ^ 

Wave-length Determinations and General Results obtained from a 
Detailed Examination of Spectra photographed at the Solar Eclipse 
of January 22, 1898. By J. Evershed. Communicated by Dr. 
RambautjF.RS ^ 6 

The Thermo- Chemistry of the Alloys of Copper and Zinc. By T. J. 
Baker, B.Sc., King Edward's School Birmingham. Communicated 
by Professor Poynting, F.R.S 9 

A Chemical Study of the Phosphoric Acid and Potash Contents of the 
Wheat Soils of Broadbalk Field, Rothamsted. By Bernard Dyer, 
D.Sc, F.I.C. Communicated by Sir J. Henry Gilbert, F.R.S 11 

Meeting of February 7, 1901, and Proceedings 14 

List of Papers read 15 

Further Investigations on the Abnormal Outgrowths or Intumescences 
in Hibiscus vitifoliuSy Linn. : a Study in Experimental Plant 
Pathology. By Elizabeth Dale. Communicated by Professor H. 
Marshall Ward, F.RS ^ 16 

The Integration of the Equations of Propagation of Electric Waves. 
By A. E. H. Love, F.RS 19 

On the Proteid Reaction of Adamkiewicz^ with Contributions to the 
Chemistry of Glyoxylic Acid. By F. Gowland Hopkins, M.A., 
M.B., University Lecturer in Chemical Physiology, and Sydney W, 
Cole, B.A., Trinity College. (From the Physiological Laooratories, 
Cambridge.) Communicated by Dr. Langley, F.RS. .. .~ ^\ 



IV 

Page 
Preliminary Determination of the Wave-lengths of the Hydrogen 
Lines, derived from Photographs taken at Ovar at the Eclipse of the 
Sun, 1900, May 28. By F. W. Dyson, M.A., Sec. RA.S. Com- 
municated by W. H. M. Christie, C.B., M.A., F.RS 33 

On the Brightness of the Corona of January 22, 1898. Preliminary 
Note, By H. H. Turner, D.Sc., F.RS., Savilian Professor 36 

The Boiling Point of Liquid Hydrogen, determined by Hydrogen and 
Helium Gas Thermometers. By James Dewar, M.A., LL.D., Pro- 
fessor of Chemistry at the Boyal Institution, and Jacksonian Pro- 
fessor, University of Cambridge 44 



No. 443. 
Meeting of February 14, 1901, and Proceedings 55 

On the Influence of Ozone on the Vitality of some Pathogenic and 
other Bacteria. By Arthur Ransome, M.D., F.B.C.P., F.RS., and 
Alexander G. R Foulerton, F.RC.S .• 55 

On the Functions of the Bile as a Solvent By Benjamin Moore and 
William H. Parker. Communicated by Professor Schafer, F.RS 64 

On the Application of the Kinetic Theorjr of Gases to the Electric, 
Magnetic, and Optical Properties of Diatomic Gases. By George 
W. Walker, B.A., A.RC.Sc, Fellow of Trinity College, Cambridge, 
Sir Isaac Newton Research Student Commnnicatea by Professor 
Rucker, Sec. RS 77 

Meeting of February 21, 1901, and Proceedings 78 

An Attempt to Estimate the Vitality of Seeds by an Electrical Method. 
By Augustus D. Waller, M.D., F.RS 79 

On a New Manometer, and on the Law of the Pressure of Gases 
between 1*5 and O'Ol Millimetres of Mercurv. By Lord Rayleigh, 
F.RS ;. 92 

An Investigation of the Spectra of Flames resulting from Operations 
in the Open-hearth and "Basic" Bessemer Processes. By W. N. 
Hartley, F.RS., Royal College of Science, Dublin, and Hugh 
Ramage, A.RC.Sc.1., St. John's College, Cambridge 93 

The Mineral Constituents of Dust and Soot from various Sources. By 
W. N. Hartley, F.RS., Royal College of Science, Dublin, and Hugh 
Ramage, A.RC.Sc.L, St John's CoUege, Cambridge 97 

Notes on the Spark Spectrum of Silicon as rendered by Silicates. By 
W. N. Hartley, F.RS „ 109 

Some Additional Notes on the Orientation of Greek Temples, being 
the Result of a Journey to Greece and Sicily in April and May, 1900. 
By F. C. Penrose. M.A., F.RS 112 

Meeting of February 28, 1901, and Address to the King ; 115 

His Majesty's Reply 116 

^*8t of Papers read 116 



V 

Page 
On the Structure and Affinities of Fossil Plants from the Paleozoic 
Rocks. IV. The Seed-like Fructification of Lepidocarpon, a (xenus 
of Lycopodiaceous Cones from the Carboniferous Formation. By 
D. H. Scott, M.A., Ph.D., F.RS., Hon. Keeper of the Jodrell 
Laboratory, Royal Gardens, Kew 117 

On the Theory of Consistence of Logical Class-frequencies and its Geo- 
metiical Representation. By G. Udny Yule, formerly Assistant Pro- 
fessor of Applied Mathematics in University College, London. 
Communicated by Professor K. Pearson, F.RS 118 

The N ew Star in Perseus. —Preliminary Note. By Sir Norman Locky er, 
K.C.B., F.RS 119 



No. 444. 

Meeting of March 7, 1901, and List of Candidates 124 

List of Papers read 125 

On the Conductivity of Gases under the Becquerel Rays. By the Hon. 
R. J. Strutt, Fellow of Trinity College, Cambridge. Communicated 
by Lord Rayleigh, F.RS .'. 126 

Some Physical Properties of Nitric Acid Solutions. By V. H. Veley, 
F.R.S., and J. J. Manley, Daubeny Curator, Magdalen Cbllege, 
Oxford 128 

Tlie Anatomy of Symmetrical Double Monstrosities in the Trout. B^' 
James F. Gemmill, M.A., M.D., Lecturer iu Embryology and Uni- 
versity Assistant in Anatomy, University of Glasgow. Communi- 
cated by Professor Clelaud, F.RS 129 

Preliminary Communication on the (Estrous Cycle and the Formation of 
the Corpus Luteum in the Sheep. By F. H. A. Marshall, B. A. Com- 
municated by Professor J. C. Ewart, F.RS 135 

On the Composition and Variations of the Pelvic Plexus in AcarUhias 
vulgaris. By R C. Punnett, B.A., Gonville and Caius College, Cam- 
bridge. Communicated by Dr. H. Gadow, F.RS 140 

Further Observations on Nova Pei*sei. By Sir Norman Lockyer, K.C.B., 
F.RS. (Plate 1) 142 

Meeting of March 14, 1901, and List of Papers read 146 

The Action of Magnetised Electrodes upon Electrical Discharge 
Phenomena in Rarefied Gases. By C. E. S. Phillips. Communicated 
by Sir William Crookes, F.RS 147 

The Chemistry of Nerve-degeneration. By F. W. Mott, M.D., F.R.S., 
and W. D. Halliburton, M.D., F.RS 149 

On the lonisation of Atmospheric Air. By C. T. R Wilsou, M.A., 
F.rA, Fellow of Sidney Sussex College, Cambridge 161 

On the Preparation of Large Quantities of Tellurium. Bv Edward 
Matthey, A.RS.M. Communicated by Sir George Stokes, Bart., 
F.RS 161 



VI 

Page 
The Transmission of the Trypanosoma Evansi by Horse Flies, and other 
Experiments pointing to the probable Identity of Surra of India 
ana Nagana or Tsetse-fly Disease of Africa. J3y Leonard Rogers, 
M.D., M.R.C.P., Indian Medical Service. Communicated by Major 
D. Bruce, RA.M.C, F.RS 163 

Meeting of March 21, 1901, and Lecture delivered 170 

Meeting of March 28, 1901, and List of Papers read 170 



No. 446. 

On the Results of Chilling Copper-Tin Alloys. By C. T. Heycock, 
F.R.S., and F. H. Neville, F.R.S. (Plates 2-3) 171 

On the Enhanced Lines in the Spectrum of the Chromosphere. By 
Sir Norman Lockyer, K.C.B., F.R.S., and F. E. Baxandall, A.RC.S. 178 

On the Arc Spectrum of Vanadium. By Sir Norman Lockyer, K.C.B., 
F.RS., and F. E. Baxandall, A.R.C.S 189 

A Preliminary Account of the Development of the Free-swimming 
Nauplius of Leptddora hyalina {lAW].), By Ernest Warren, D.Sc, 
Assistant Professor of Zoology, University College, London. Com- 
municated by Professor Weldon, F.RS « 210 

The Growth of Magnetism in Iron under Alternating Magnetic Force. 
By Ernest WiJson. Communicated by Professor J. M. Thomson, 
F.RS 218 

On the Electrical Conductivity of Air and Salt Vapours. By Harold 
A. Wilson, D.Sc, M.Sc., B.A., Allen Scholar, Cavendish Laboratory, 
Cambridge. Communicated by Professor J. J. Thomson, F.RS 228 

Further Observations on Nova Persei, No. 2. By Sir Norman Lockyer, 
KC.R, F.RS 230 



No. 446. 

Elastic Solids at Rest or in Motion in a Liquid. By C. Chree, ScD., 
LL.D., F.RS 236 

On the Heat dissipated by a Platinum Suiiace at High Temperatures. 
Part IV.— High-pressure Gases. Bv J. E. Petavel, A.M.I.C.E., 
A.MI.E.E., John Harling Fellow of Owens College, Manchester. 
Communicated by Professor Schuster, F.RS 246 

Meeting of May 2, 1901, Names of Candidates recommended for elec- 
tion, and List of Papers read 248 

Ellipsoidal Harmonic Analysis. By G. H. Dai- win, F.R.S., Plumian 
Professor and Fellow of Trinity College in the University of Cam- 
bridge .*! 248 

On the Small Vertical Movements of a Stone laid qn the Surface of the 
Ground, ^y Horace Darwin. Communicated by Clement Reid, 
F.RS 263 

^ Meeting of May 9, 1901, and Proceedings 261 



vu 

Pftf?6 

Meeting of May 23, 1901, and List of Papers read. ^,^ 262 

On Negative After-images, and their Relation to certain other Visual 
Phenomena. By Shelford Bidwell, M.A., ScD., F.R.S 262 

The Solar Activity, 1833-1900. By William J. S. Lockyer, M.A., 
PhD., F.RAS., Assistant Director, Solar Physics Observatory, 
Kensington. Communicated by Sir Norman Lockyer, K.C.B., 
F.RS 285 



No. 447. 

On the Variation in Gradation of a Developed Photomphic Image 
when impressed by Monochromatic Light of Different W a ve-lengths. 
By Sir William de W. Abney, KC.B., D.C.L., D.Sc., F.RS 300 

A Comparative CrystallogTaphical Study of the Double Selenates of 
the Series R,M(SeOJ},6H,0— Salts in which M is Magnesium. By 
A. E. Tutton, B.Sc., F.RS 322 

On the Presence of a Glycolytic Enzyme in Muscle. By Sir T. Lauder 
Brunton, MD., F.RS., and Herbert Rhodes, M.B 323 

Annual Meeting for the Election of Fellows ^ 326 

Meeting of June 6, 1901, and List of Papers read 327 

Vibrations of Rifle Barrels. By A. Mallock. Communicated by Lord 
Rayleigh, F.RS 327 

A Conjugating " Yeast." By R T. P. Barker, R A, Gonville and Caius 
College, Cambridge. Communicated by Professor Marshall Ward, 
F.RS. ^^ 345 

The Measurement of Ms^etic Hysteresis. Bv G. F. C. Searle, MA., 
and T. G. Bedford, M.A. Communicated by Professor J. J. 
Thomson, F.RS ^ 348 

Thermal Adjustment and Respiratoir Exchange in Monotremes and 
Marsupials. — A Study in the Development of Homothermism. By 
C. J. Martin^ M.B., D.Sc., Acting Professor of Physiology in the 
University of Melbourne. Communicated by Professor K H. 
Starling, F.RS 352 

On the Elastic Equilibrium of Circular Cylinders under certain Practical 
Systems of Load. By L. N. G. Filon, MA., B.Sc, Research Student 
of King's College. Cambrid^ ; Fellow of University College, 
London ; 1851 Exhibition Science Research Scholar. Communi- 
cated by Professor Ewing, F.RS 353 

The Measurement of Tonic Velocities in Aqueous Solution, and the 
Existence of Complex Ions. By B. D. Steele, RSc, 1851 Exhibition 
Scholar (Melbourne). Communicated by Professor Ramsay, F.RS... 358 

Na44a 
Meeting of June 13, 1901 360 

Baksrian Lbcturb.— The Nadir of Temperature, and Allied Problems. 
1. Phyeical Properties of Liquid and Solid Hydrogen. 2. Separation. 



VIU 

PuRe 

of Free Hydrogen and other Ga^es from Air. 3. Electric Resistance 
Thermometry at the Boiling Point of Hydrogen. 4. Experiments on 
the Liquefaction of Helium at the Melting Point of Hydrogen. 
5. Pyroelectricity, Phosphorescence, &c. By James Dewar, LL.D., 
D.Sc., F.RS., Jacksonian Professor in the Universitjr of Cambridge, 
and Fullerian Professor of Chemistry, Boyal Institution, London, &c. 360 

Meeting of June 20, 1901, and List of Papers read 366 

On the Mathematical Theory of Errors of Judgment, with Special Re- 
ference to the Personal Equation. By Kari Pearson, F.R.S., Uni- 
versity College, London 369 

Mathematical Contributions to the Theory of Evolution.— X. Supple- 
ment to a Memoir on Skew Variation. By Karl Pearson, F.R.S., 
University College, London 372 

On the Structure and AflBnities of Dipterisy with Notes on the Geological 
History of the Dipteridinae. By A. C. Seward, F.RS., University 
Lecturer in Botany, Cambridge, and Elizabeth Dale, Pfeiffer Student, 
Girton College, Cwnbridge 373 

The Nature and Origin of the Poison of Lotus arabicue. By Wyndhani 
R Dunstan, M.A., F.RS., Director of the Scientific and Technical 
Department of the Imperial Institute, and T. A. Henry, B.Sc., 
Salters' Company's Research Fellow in the Laboratories of the Im- 
perial Institute ^ „ ^ 374 

The Pharmacology of Pseudaconitine and Japaconitine considered in 
Relation to that of Aconitine. Bjr J. Theodore Cash, M.D., F.RS., 
Regius Professor of Materia Medica in the University of Aberdeen, 
and Wyndham R. Dunstan, M.A., F.RS., Director of the Scientific 
Department of the Imperial Institute 378 

The Pharmacology of Pyraconitine and Methylbenzaconine considered 
in relation to their Chemical Constitution. B^ J. Theodore Cash, 
M.D., F.RS., Renins Professor of Materia Medica in the University 
of Aberdeen, and Wyndham R Dunstan, M. A., F.RS., Director of 
the Scientific Department of the Imperial Institute 384 

Ou the Se[)aration of the Least Volatile Gases of Atmospheric Air, and 
their Spectra. By G. D. Liveing, M.A., ScD., F.RS., Professor of 
Chemistry in the Universi^ of Ounbridge, and James Dewar, M.A., 
LL.D., F.RS., Jacksonian Professor in the Universitv of Cambridge, 
Fullerian Professor of Chemistry, Royal Institution, ^London 389 

Further Observations on Nova Persei. No. 3. By Sir Norman 
Lockyer, K.C.B., F.RS ^ 399 

Total Eclipse of the Sun, May 28, 1900. — ^Account of the Observations 
made by the Solar Physics Observatory Ecli]>se Expedition and the 
Oflicersand Men of H.M.S. "Theseus" at Santa Pola, Spain. By 
Sir Norman Lockyer, K.C.B., F.RS 404 

Preliminary Statement on the Prothalli of Ophioglouum pendulum (L.), 
HelmirUhostachyt zeylanica (Hook.), and Fnlotum, sp. By William 
H. Lang, M.B., D.Sc, Lecturer in Botany, Queen Margaret College, 
University of Glasgow. Communicated by Professor F. O. Bower, 

OCX/., T . X«.0. •^.•.••.••.••••••.•••••.••••M«...*.a«M.Ma«««f«*M. .*••••■••••••••■..•••*••■•.••* ••*••*. 4UO 



IX 

No. 449. 

Page 
The Mechanism of the Electric Arc. By (Mrs.) Hertha Ayrton. Com- 
municated by Profesgor Perry, F.RS .^.... 410 

Report of Magnetical Observations at Falmouth Observatory for the 
Year 1900 416 

The National Physical Laboratory. Beport on the Observatory Depart- 
ment for the Year ending December 31, 1900 421 

The Stability of a Spherical Nebula. By J. H. Jeans, R A., Scholar of 
Trinity College, and Isaac Newton Student in the University of 
Cambridge. Communicated by Professor G. H. Darwin, F.RS 454 

The Spectrum of i| Argus. By Sir David Gill, K.C.B., LL.D., F.RS., 
H.M. Astronomer at the Cape (Plate 4) 466 

Cboonian Lecthrb. — Studies in Visual Sensation. By C. Lloyd 
Morgan, F.RS., Principal of University College, Bristol .^ 469 

The Yellow Colouring Matters accompanying Chlorophyll and their 
Spectroscopic Relation& Part IL By C. A. Schunck. Commu- 
nicated by Dr. R Schunck, F.RS. (Plates 6, 6) ^ 474 



No. 460. 

On Skin Currents.— Part L The Frog's Skin. By Augustus D. Wal- 
ler, M.D., F.RS ^ 480 

Virulence of Desiccated Tubercular Sputum. By Harold Swithin- 
bank. Communicated by Sir James Crichton Browne, F.RS. 496 

Effect of Exposure to Liquid Air upon the Vitality and Virulence of 
the Bacillus Tuberculosis. By ti. Swithinbank. Communicated by 
Sir James Crichton Browne, F.B.S 498 

On the Behaviour of Oxy-haemoglobin, Carbonic-oxide-haomoglobin, 
Methsemofflobin, and certain of their Derivatives, in the M^netic 
Field, wiui a Preliminary Note on the Electrolysis of the Hsemo- 
globin Compounds. By Arthur Gamgee, M.D., F.RS., Emeritus 
Professor of Physiology in the Owens College, Victoria University.... 603 

On the Resistance and Electromotive Forces of the Electric Arc. Bv 
W. DuddelL Whitworth Scholar. Communicated by Professor W. 
E. Ayrton, F.RS 612 

Index. <. ^ 619 



PROCEEDINGS 



OF 



THE ROYAL SOCIETY. 



January 17, 1901. 

Sir WILLIAM HUGGINS, K.C.B., 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 : — 

I. " Total Eclipse of the Sun, January 22nd, 1898. Observations at 
Viziadrug. — Part IV. The Prismatic Cameras." By Sir 
Norman Lockyer, K.C.B., F.R.S. 

II. " Wave-length Determinations and General Results obtained from 
a Detailed Examination of Spectra photographed at the Solar 
Eclipse of January 22, 1898." By J. EvERSHED. Communi- 
cated by Dr. Rambaut, F.R.S. 

III. " The Thermo-chemistry of the Alloys of Copper and Zinc." By 
T. J. Baker. Communicated by Professor Poynting, F.R.S. 



*' Mathematical Contributions to the Theory of Evolution. IX. — On 
the Principle of Homotyposis and its Relation to Heredity, to 
the Variability of the Individual, and to that of the Race. 
Part I. — Homotyposis in the Vegetable Kingdom." By Kakl 
Pearson, F.R.S., with the assistance of Alice Lee, D.Sc, 
Ernest Warren, D.Sc., Agnes Fry, Cicely I). Fawcett, B.Sc, 
and othera. Received October 6, — Read November 15, 1900. 

(Abstract.) 

(1.) If we take two offspring from the same parental pair, we find a 
certain diversity and a certain degree of resemblance. In the theory 
VOL. LXVIII. "B 



2 Prof. Karl Pearson, and others. 

of heredity we speak of the degree of resemhlance as the fraternal 
correlation, while the intensity of the diversity is measured by the 
standard deviation of the array of offspring due to given parents. 
Both correlation and standard de\iation are determined for any given 
character or organ by perfectly definite well-known statistical methods. 
Passing from the case of bi-parental to asexual reproduction, we may still 
determine the correlation and variability of the offspring. This ulti- 
mately leads us to the measurement of the diversity and likeness of 
the products of pure budding, or, going still one stage further, we 
look, not to the reproduction of new individuals, but to the production 
of any series of like organs by an individual. Accordingly one reaches 
the following problem : — If an individual produces a number of like 
organs, which so far as we can ascertain are not differentiated, what is 
the degrees of diversity and of likeness among them 1 Such organs 
may be blood-corpuscles, hairs, scales, spermatozoa, ova, buds, leaves, 
flowers, seed-vessels, &c., &c. Such organs I term hamohjpes when 
there is no trace to be found between one and another of differentiation 
in function. The problem which then arises is this: — Is there a 
greater degree of resemblance between homotypes from the same 
individual than between homotypes from separate individuals 1 If fifty 
leaves are gathered at random from the same tree and from twenty- 
five different trees, shall we be able to determine from an examination 
of them what has been their probable source 1 Are homotypes from 
the individual only, a random sampling, as it were, of the homotypes of 
the race 1 

By the examination of very few series from the animal and 
vegetable kingdoms I soon reached the result, that homotypes, like 
brothers, have a certain degree of resemblance and a certain degree 
of diversity ; that imdifferentiated like organs, when produced by the 
same individual, are, like types cast from the same mould, more 
alike than those cast by another mould, but yet not absolutely identi- 
cal. I term this principle of the likeness and diversity of homotypes 
Jumwtyposis, It soon became clear to me that this principle of homo- 
typosis is very fundamental in nature. It must in some manner 
be the source of heredity. It does not, of course, ** explain " 
heredity, but it shows heredity as a phase of a much wider process 
— the profluction by the individual of a series of undifferentiated-like 
organs with a certain degree of likeness. My first few series 
seemed to show that the homotyposis of the vegetable and animal 
kingdoms had approximately the same value, and it occurred to me 
that we had here the foundation of a very widespread natural law. 
In order to demonstrate its truth, however, the homotyposis of a large 
range of characters in a great number of species must be investigated, 
and I soon found my own unaided efforts were quite unequal to the 
kt^k of collecting, tabulating, and reducing the data. As the 



Matheinatical Contributions to the Theory of Evolution, 3 

material grew, it seemed desirable to separate the vegetable and 
animal kingdoms, and the present paper deals only with the former.' 
In this field I have had the aid of a number of competent helpers. To 
collaborators who have long aided me, like Dr. Alice Lee, Miss C. D. 
Pawcett, and Mr. Leslie Bramley-Moore, I have been able to add, for 
the present purpose, Miss Agnes Fry, Dr. E. Warren, Dr. W. R. 
Macdonell, Miss M. Barwell and others, who have taken part in the 
labour either of collection, of measurement, or of computation. The 
result of this united labour is that twenty-two series, with upward of 
twenty-nine correlation tables, are here dealt with.* Small in number 
as this may seem, when we think of the vast variety of the vegetable 
kingdom, it means an immense amount of work — special series, which are 
in the memoir represented by a page of t^ble and a few lines of 
numerical constants, have often cost one or other of us weeks of steady 
work. Hence I cannot strongly enough express my gratitude to ray 
co-workers ; they have more than ever convinced me of the great im- 
portance of co-operation for the future of scientific research, and the 
desirability, if possible, of organising the labour of isolated scientific 
workers. I will now indicate the general results we have reached. 

(2.) The following series were dealt with : (1) to (3). The leaflets of 
the compound leaf of the Ash were counted in upwards of 300 trees 
from Buckinghamshire, Dorsetshire, and Monmouthshire. The results 
were in good agreement, and show homotyposis as a racial character of 
considerable constancy. (4) to (5) The veins in the leaf of the Spanish 
Chestnut were counted in 100 trees from Buckinghamshire and 100 
trees of mixed character. Homot^'posis was found to increase with 
heterogeneity of age and locality. (6) The veins were counted in the 
leaves of 100 Beech trees from Buckinghamshire. (7) and (8) The 
prickles were coimted on the leaves of 100 Holly trees from Somerset- 
shire and 100 from Dorsetshire. This completes the series of homo- 
types for trees. The tree results are in fair accordance, when we allow 
for the disturbing factors of environment, age, and personal selection. 
(9) to (13) We next investigated five series of Poppies, counting the 
stigmatic bands on the seed-capsules ; Fapaver Bhceas for three series, 
from top of Chiltems, bottom of Chilterns, and the Quantocks ; Shirley 
Poppies for two series from Great Hampden and Chelsea. The results 
were again in fairly reasonable accordance with each other and with 
those for trees. (14) and (15) The segmentation of the seed vessels 
was counted in Ni^ella Hispanica and Malva Rotandifolia ; the homotyp- 
osis was found to be much weakened, but actual differentiation was 
observed between the seed vessels on the main stem and on the side 
shoots of the former, and the 127 plants of the latter had principally 
arisen by stolons from a single clump, and were not thus entirely in- 
dependent individuals. (16) The members of the whorls were counted 

* In the Append'x an additional fifteen scries w.ll be CouuOl. 

Y.1 



4 Prof. Karl Pearson, and others. 

in 201 sprays from separate plants of Asperala odorata ; it was known 
that these members are differentiated in their origin ; the homotyposis 
was found much weakened. (17) and (18) The sm-i on the fronds 
of 100 Hartstongue ferns and the lobes on the fronds of 100 
plants of Ceterach were counted. We were told that these charac- 
ters are much affected by age of plant and environment of indi- 
vidual; we found the homotyposis increased very sensibly beyond 
the value obtained for trees. (19) The veins in the timics of 200 
examples of Allium cepa were counted. (20) The seeds in the pods of 
100 plants of Broom from Yorkshire were coimted. In an Appendix 
the homotyposis of the seeds in the ix)ds of leguminous plants is dealt 
with for a number of species. The general result is that homotypic 
intensity is halved when we deal with a character associated with 
fertilisation. 

We then considered two cases in which we knew the growth factors 
to be very marked. Dr. E. Warren measured the length and breadth 
of twenty-five leaves of 100 plants of common ivy (Hedera Helix) 
and Dr. Lee and myself the length and breadth of ten gills of 107 
Mushrooms {Afjaricus campestris). The homotyposes of the leaf and of 
the gill indices in these two cases were determined, and form series (21) 
and (22). The homotypic correlation of the absolute lengths and 
breadths was also found in order to obtain some measure of the effect 
of different stages of growth on homotyposis. Omitting the last series 
of absolute measurements subject to growth, the mean value of the 
twenty-two series gave the intensity of homotypic correlation as 0*4570. 

(3.) A theory of fraternal hereditary resemblance is given on the basis 
of the likeness of brothers being due to homotyposis in the characters 
of spermatozoa and ova put forth by the same two individuals and 
uniting for the zygotes whence the brothers arise. It is found that the 
mean value of fraternal correlation ought to be equal to the mean in- 
tensity of homotypic correlation. We have so far worked out nineteen 
cases of fraternal correlation in the animal kingdom, and their mean 
value = 0*4479, i.e., is sensibly equal to the intensity of homotyposis 
in the vegetable kingdom. It is, therefore, very probable that heredity 
is but a phase of homotyposis, and that the latter approximates to a 
•certain value throughout living forms. 

The theory involves a certain mean relation between direct and 
cross homot\^)osis, i.e., that the homotypic correlation between char- 
acters A and B in a pair of homotypes is the product of the direct 
homot}'3)ic correlation of A and A (or B and B) and the organic corre- 
lation of A and B in the individual. We had only the absolute 
lengths and breadths of Ivy leaves and Mushroom gills to test this 
proposition on, and the growth factor is here dominant. The results 
<io not show complete equality, but this is hardly to be wondered at 
when we consider the extraneous influences at work. 



Mathematical Contnbutioiis to the Thcoi*y of Evolution. 5 

(4.) The individual variation in the twenty-two series was measured 
and expressed as a percentage of the racial variation ; the results range 
from 77 to 98 per cent., with a mean value of 87 per cent. If this 
percentage variation occurs within the individual, it is clearly idle to 
speak of variation as a result of sexual reproduction. It exists in full 
intensity when an individual buds or throws off undifferentiated liko 
organs. The blood-corpuscles produced by a single frog are almost as 
variable as the blood-corpuscles in the whole race of frogs. Thus, 
variation is establiahed as a primary feature of all vital production 
whatever. 

(5.) No relation whatever could be found between the intensity of 
homotyposis (and therefore a fortiori of heredity) and the degree of 
variability of the species. If species are classified in order of variability 
for our twenty-two series, the mean homotjrposis of the first eleven is 
0*4559 and of the last eleven is 0*4570. No relation whatever, as far as we 
were able to judge, could be found between the simplicity or complexity 
of the organisms dealt with and either their variability or their homotyp- 
osis. The Mushroom was quite comparable with the Poppy or the 
Spanish Chestnut. We conclude, accordingly, that there is no evidence 
at present to show that variation has decreased and heredity increased 
with the progress of evolution. On the contrary, without laying down 
any dogma, we should consider thejresults obtained as consistent with 
variability and homotyposis being primary factors of the growth of all 
living forms and not the product of natural selection, but factors upon 
which its effectiveness ah initio has depended. If we can show that 
homotypic correlation is as intense in the simplest forms of life as in 
the most complex, and that inheritance flow^s. naturally from it, it is 
clear that our view of living forms will be considerably simplified. 
Homotyposis is unfortunately obscured by other factors due to growth, 
environment, unobserved differentiation, or heterogeneity in one or 
another form. But the results of this our first investigation in this 
field seem to support the view just expressed, and to indicate that the 
Principle of Homotyposis (by which we must again say we mean a 
numeriad appreciation of the likeness and diversity among homotypes) 
is a fundamental law of nature, which will enable us to sum up in a 
brief formula a great variety of vital phenomena. 



Total Eclipse of 11x4^ Sun, January 22, 1898. 



** Total Eclipse of the Sun, January 22nd, 1898. Observations 
at Viziadrug. — Part IV. The Prismatic Cameras." By Sir 
Norman Lockykr, K.C.B., F.B.S. Received December 22, 
1900— Read January IT, 1901. 

(Abstract.) 

The report gives full particulars concerning the 6-inch and 9-inch 
prismatic cameras which were used during the eclipse, and the results 
obtained. Twenty-four of the photographs are reproduced. A table 
is given indicating the wave-lengths and probable origins of the 
856 lines which have been measured between D and A. 3663. 

The investigation shows the probable presence of both arc and 
enhanced lines of calcium, chromium, iron, manganese, nickel, stron- 
tium, titanimn and possibly cobalt, copper, indium, lead, molybde- 
num, potassium, and rubidium ; arc lines of aluminium, barium, carbon, 
magnesium, sodium, scandium and possibly cerium, lanthanum, lithium, 
rhodium, and tantalum ; enhanced lines of vanadium, and possibly of 
bismuth, cajsium, gold, ruthenium, selenium, silieium, thallium, tin, 
tungsten, yttrium, zinc, and zirconium. Hydrogen, helium, and 
asterium are also present. 

No evidfence has been found of the presence of antimony, arsenic, 
cadmium, iridium, mercury, osmium, palladium, platinum, silver or 
thorium. Fiu1»her investigations of the coronal rings have led to no 
definite results regarding their origins. 



*' Wave-length Determinations and General Results obtained from 
a Detailed Examination of Spectra photographed at the Solar 
Eclipse of January 22, 1898." By J. Eveksued. Gonmmni- 
cated by Dr. Rambaut, RRS. Received December 12, 1900 
—Read January 17, 1901. 

(Abstract.) 

In this paper the results are given of a dctiiiled study and 
moasurement of a series of spectra photographed at the eclipse of 
1898, with a glass prismatic camera of 2 J inches aperture. Ten 
exposures were made, all yielding good negatives, in which the great 
extension in the ultra-violet is a marked featm*e. 

The first two photographs of the series were exposed at 20 

seconds and 10 seconds before totality respectively, and are images of 

the cusp spectrum. They show the Fraunhofer lines with groat 

. distinctness, although the latter are much less dark than in the 



Cftrural Remits obtained from 1898 Eclipse Spectra. 7 

ordinary solar spectrum. The lines were measured and identified 
for the purpose of facilitating the reduction of the bright line spectra 
obtained during, totality. 

Spectrum No. 3 was exposed for f uiu* seconds, beginning two seconds 
before second contact. In this the flash spectrum is fully developed, 
and extends from A. 3340 to A. 6000. The majority of the bright 
arcs, including those due to the upper chromosphere, extend over 40* 
of the limb, implying a depth of r''3 for the gases composing this 
layer. The total depth of the chromosphere deduced from the 
hydrogen arcs is 8" -2, and from the calcium arcs IT'-G. There are 
313 measurable lines in this negative, and the wave*lengths and 
identifications of these are given in Table L 

Spectrum No. 4, exposed for, half a second shortly after second 
contact, gives the spectrum of the upper chromosphere and pro- 
minences. Seven of the latter are shown. The images are about 
equally dense in calcium radiations, although in hydrogen there is a 
marked variation of intensity between the different prominences. 

A conspicuous featiu'e in the spectrum of two of the prominences is 
a band of continuous spectrum, beginning at A. 3668 near the end of 
the hydrogen series, and extending indefinitely in the ultra violet. 

Good measiu'es were obtained of the images of a small prominence 
at the centre of the plate, the wave-lengths being given in Table II. 

Spectrum No. 5.— This plate had a long exposure near mid-totality. 
The continuous spectrum of the corona is strongly marked, and the 
green corona line is well shown at position angles 60' to 78°, and 95** 
to 105**. A new corona line is faintly imj)ressed at A. 3388 ± , the 
maxima of intensity being at the same position angles as those of the 
green line. 

Spectrum No. 7 shows the re-appearing arcs of the flash spectrum, 
the exposure ending about four seconds before third contact. The 
green corona line is shown on both east and west limbs, and there is 
a faint corona line near H. The wave-length values of the lines 
measured on this plate are given in Table I. 

Spedmm No. 8. — This was exposed almost at the instant of third 
contact, the re-appearing photosphere showing as four narrow bands of 
continuous spectnmi due to Baily's beads. The flash spectrimi arcs 
extend between and across the bands, and can be traced over an arc of 
55% the depth of the layer, in this case exceeding 2". 

The focus in this negative is poor, and no measures were made ; but 
as far as can be judged, comparing this plate and No. 3, the spectra of 
the east and west limbs of the sun are identical. 

Spectra Nos. 9 and 10. — These are cusp spectra, very similar to 
Nob. 1 and 2. 



8 General Results obtained from 1898 Eclipse Spectra, 

General Remits and Conclusions, 

The Flash Spectrum, — Comparing the wave-length values of the flash 
spectra given in Table I with Rowland's wave-lengths of the solar 
lines, it is at once evident that practically all the strong dark solar 
lines are present in the flash as bright lines ; and all the bright lines 
in the flash, excepting hydrogen and helium, coincide with dark lines 
having an intensity greater than three on Rowland's scale. 

The relative intensities of the lines in the two spectra are, however, 
widely diffbrent, many conspicuous flash lines coinciding with weak 
solar lines, and some of the strong solar lines being represented by 
weak lines in the flash spectrum. 

This, however, applies only to the spectrum taken as a whole. 
Selecting the lines of any one element, it is found that the relative 
intensities in the flcish spectrum agree closely with those of the same 
element in the solar spectrum. This is particularly well shown in the 
case of the elements iron and titanium. 

The want of agreement in the relative intensities of the lines of 
different elements in the bright line and dark line spectra is probablj 
due to the unequal heights to which the various elements ascend in 
the chromosphere, a low-lying gas of great density giving' strong 
absorption lines, but weak emission lines, on account of the excessively 
small angular width of the radiating area. • 

The more extensively diffused gases of small density, on the other 
hand, give strong emission lines in the flash spectrum, and weak 
absorption lines. 

The spectnmi arcs obtained with a prismatic camera are not true 
images of the strata producing them, but diffmdum images more or 
less enlarged by photographic irradiation. Monochromatic radiations 
from a layer. 2" in depth will produce arcs or "lines" which are as 
narrow as can be defined by instruments of ordinary resolving power. 

The intensities of these images do not represent the intrinsic 
intensities of the bright lines of the different elements ; the apparent 
intensity of the radiation from an element depending on the extent of 
diffusion of that element Jibove the photosphere. 

But in the dark line spectrum the intensities depend on the total 
quantity of each absorbing gas above the photosphere irrespective of 
the state of diffusion of the different elements. 

The flash spectrum as a whole appears from these results to repre- 
sent the upper, more extensively diffused portion of a stratiun of gas, 
which, by its absorption, gives the Fraunhofer spectrum. 
. Fifteen elements are recognised with certainty in the flash spectrum 
(No. 3), and five are doubtfully present. The atomic weights of these 
elements in no case exceed 91. All the known metals having atomic 
weights between 20 and 60 seem to b6 present in the lower chromo- 



The ThemiO'Chemisfry of the Alloys of Copper ccTid Zinc. 9 

sphere, but among these there does not seem to be any relation 
l)etween the atomic weights and the elevations to which the gases 
ascend in the chromosphere. 

The only non-metals found are H, He, C, and possibly Si. 

Of the 225 lines measured in the ultra-violet region of the spectrum 
only 29 remain unidentified. 

The Hydrogen Spectrum, — Twenty-eight hydrogen lines are shown 
in spectrum No. 3. The wave-lengths obtained are compared in 
Table III with the theoretical values derived from Balmer^s formula. 
With the exception of H8, which seems to be unfvccountably displaced 
towards the red, the wave-lengths of the ultra-violet lines are found to 
agree closely with the formula. A slight deviation occurs in the most 
refrangible lines, the positions of which seem to be distinctly more 
refrangible than those assigned by theory. 

The continuous spectrum given by the prominences in the ultra- 
violet, beginning at the end of the hydrogen series, seems analogous to 
a feature noticed by Sir William Huggins in the absorption spectra of 
Ist type stars, and is possibly due to hydrogen. 

Hydrogen and Helium in the Lower Chromosphere. — From the character 
of some of the helium lines it is inferred that this element is probably 
absent from the lowest strata, whilst parhelium appears to be separated 
from helium, and to exist at a lower level. . ' ■" 

Unlike helium, hydrogen gives very intense lines in the flash layer. 
These lines are well defined and narrow, even in the very lowest strata. 

R^stsons are given to show that the absence of hydi-ogen absorption in 
the ultra-violet, and of helium absorption in the visible spectnim, may 
be due to insuflScient quantity of these elements above the photosphere, 
not to equality of temperature between the radiating gas and photo- 
spheric backgroimd. 

The Corona Spertrum. — The wave-length of the green line deduced 
from measures of No. 3 and No. 7 spectra confirms the value obtained 
by Sir Norman Lockyer at the same eclipse. The only other lines 
shown on these photographs are at A. 3388 and near H. 



" The Thermo-chemistry of the Alloys of Copper and Zinc." By 
T. J. Baker, B.Sc., King Edward's School, Birmingham. 
Communicated by Professor Poynting, F.R.S. Heceived 
December 4, 1900.— Bead January 17, 1901. 

(Abstract.) 

The heats of formation of a number of alloys of copper and zinc, 
coiftaining those metals in very diverse proportions, have been 
ascertained. 



10 The Thermo-chemistry oftM Alloys of Copper and Zinc. 

The method consists in finding the difference between the heats of 
dissolution, in suitable solvents, of an alloy and of an equal weight of a 
mere mixture containing the metals in the same proportion. 

The first series of experiments was made with an aqueous solution 
of chlorine as solvent. Its application was limited to those alloys 
containing less than 40 per cent, of copper, as it was impossible to 
obtain those richer in copper in a sufficiently fine state of division to 
enable them to dissolve. 

The results, though not altogether satisfactory, showed that the heat 
of dissolution of an alloy was sensibly less than that of the merely 
mixed metals. 

Incidentally it was found that the equation CI2. Aq = 2600 (Thomsen's 
• Thermochemische Untersuchungen ') is erroneous and, on inquiry, 
Professor Thomsen gave a corrected value, 4870. The author finds 
Cl2.Aq = 4970. 

The most suitable solvents of the alloys are — 

(a.) Mixture of ammonium chloride and ferric chloride solutions. 

(h) Mixture of ammonium chloride and cupric chloride solutions. 

The chemical actions involved are simple reductions, and no gases 
are evolved. 

Two series of experiments made on twenty-one alloys yielded very 
concordant results. They show that heat is evolved in the formation 
of every alloy of copper and zinc yet tested. 

A sharply defined maximum heat of formation is found in the alloy 
containing 32 per cent, of copper, t.^., corresponding to the formula 
CuZn2. It amounts to 52*5 calories per gramme of alloy or 10,143 
calories per gramme-molecule. There is some evidence of a sub- 
maximum in the alloy nearly corresponding to CuZn. 

From these points there is a steady decrease in the heat of formation, 
both in the case of alloys containing less than 32 per cent, of copper 
as the amount of copper decreases, and also in the case of those con- 
taining more than 50 per cent, of copper as the quantity of copper 
increases. 

The results, in general, confirm the existence of intermetallic com- 
pounds, and the values obtained are in accordance with those demanded 
by Lord Kelvin^s calculation of the molecular dimensions of copper 
and zinc. 



On the Phosphoric Acid and Potadi Contents of Wheat Soils. 11 



•* A Chemical Study of the Phosphoric Acid and Potash Contents 
of the Wheat Soils of Broadbalk Field, Eothamsted." By 
Bernard Dyer, D.Sc., F.LC. Communicated by Sir J. Henry 
Gilbert, F.RS. Received November 9, — Bead November 15, 
1900. 

(Abstract.) 

In the * Journal of the Chemical Society ' for 1894 (vol. 65, * Trans- 
actions '), there appeared a paper by the author, " On the Analytical 
Determination of probably available * Mineral ' Plant Food in Soils," 
in which the use of a 1 per cent, solution of citric acid was proposed 
aa a means of approximate differentiation between the total and prob- 
ably available phosphoric acid and potash, the method proposed being 
the result of an attempt to imitate, in the solvent, the acidity of 
root -sap, based on a preliminary examination of the acidity of 100 
specimens of flowering plants of some twenty natural orders. To test 
the method, it was then applied to samples of the soils of the various 
barley plots in Hoos Field, Kothamsted, kindly placed at the author's 
disposal by the late Sir John Lawes and Sir Henry Gilbert. The 
method, having yielded results fairly consistent with the greatly vary- 
ing mineral history and known fertility of these various soils, has now 
been applied by the author to the investigation of the soils of a num- 
ber of the Wheat plots of Broadbalk Field, also kindly placed at his 
disposal by Sir John Lawes and Sir Henry Gilbert on behalf of the 
Lawes Agricultural Trust Committee. TwelVe representative plots 
were selected, and the samples examined include not only the surface 
soils to a depth of 9 inches, but also, for each plot, the second and 
third consecutive 9 inches of subsoil. The samples were drawn on 
the completion of the fiftieth season of continuous wheat growing, 
but earlier sets of samples, of both soils and subsoils, taken in 1865 
and 1881, were also simultaneously examined. 

The present paper gives an account of this work. It includes a 
summarised history of the manurial treatment and crop yields of each 
plot at the different periods, and gives, for each sample of soil and 
subsoil — fifty-one in all — the results of determinations of total phos- 
phoric acid and of potash soluble in hydrochloric acid ; and also of 
phosphoric acid and potash soluble in a 1 per cent, solution of citric 
acid. 

The differences between the total percentages of phosphoric acid in 
different soils, unmanured and variously manured, correspond fairly 
well with their history ; but in the absence of a knowledge of such 
history, these diff*erences would not suflBce to give any indication of 
the profound differences known to exist in the phosphatic condition 
and fertility of the soils. The relative proportions of citric acid. 



12 Dr. Bernard Dyer. Chcmicul Study of the Phosphoric 

soluble phosphoric acid, however, appear to afford a striking index 
to the relative phosphatic fertility of the soils. In the subsoils, the 
irregularities and variations in the natural and original phosphoric acid 
of the subsoils themselves are such that the total percentage tells us 
nothing; while the citric acid results frequently show striking and 
consistent differences, and arc also of considerable interest when 
studied in connection with the problems of root-range and subsoil- 
feeding, which are discussed in examining the results of the individual 
plots. In the surface soils, the average ratio of phosphoric acid, on 
the plots manured with superphosphate and ammonium salts, with and 
without various additions of alkaline salts, to that in plots not manured 
with phosphates for fifty years, was 1*65 : 1, while the citric acid 
soluble phosphoric acid ratio for the same groups was 5*46 : 1. On 
the two dunged plots the ratio of total phosphoric acid to that of the 
plots not phosphatically manured is 1*78 : I and 1-36 : 1 respectively; 
while the corresponding ratios for citric acid soluble phosphoric acid 
are 6*83 : 1 and 391 : 1. 

The probable limit denoting phosphatic deficiency for cereals seems 
to be, as deduced from this investigation, between 0*01 per cent, and 
0*03 per cent, of citric acid soluble phosphoric acid in the surface soil. 
That is to say, a percentage as low as 0*01 seems to denote an impera- 
tive necessity for phosphatic manure, while as much as 0*03 would 
seem to indicate that there is no such immediate necessity. For root- 
crops — more especially turnips — the limit would probably be higher. 

The results, generally, show that by far the greater proportion of 
unconsumed manurial phosphoric acid, though originally water-soluble, 
is accumulated in the surface or first 9 inches, but that in the case of 
dung there is considerable descent into the second and third 9 inches, 
and that, in the case of superphosphate accompanied by constant 
dressings of potassium, sodium and magnesium salts without nitrogen 
(fuir supply and small utilisation), there is evidence of a tangible 
descent into the second and even the third 9 inches. In the case of 
the chemically manured plots, not only is the greater part of the 
calculated accumulation foimd by analysis in the surface soil, but a 
large proportion of it is found in a condition in which it dissolves in a 
weak solution of citric acid. This reagent also enables us to trace 
qualitatively the descent alluded to in the subsoils. Potassium, sodium > 
and magnesium salts have a distinct influence in the retention of the 
phosphoric acid in a less fixed and presumably more available condi- 
tion, the effect increasing as the saline applications are greater. 

The superabundance of phosphoric acid estimated to have been 
supplied in dung for fifty years is less satisfactorily accounted for 
than is that on the chemically manured plots ; and even allowing for 
the difficulty of accurately estimating the phosphoric acid in the dung, 
H seems probable that there has been a considerably greater descent 



Acid and Potatsh Contents of Wheat Soils at Rothavisted, 13 

from the surface soil into the subsoil than on the chemically manured 
plots, probably accompanied by fixation of some portion in an unavail- 
able state. 

Strong hydrochloric acid, as a solvent for potash in soil analysis, is 
shown to be practically useless as a gauge of potash fertility where 
there is an abundance of total potash in mineral combination, as sili- 
cates, &c. No concordant results are obtainable except by working 
under the strictest arbitrary conditions, and the results, even when 
concordant, have little meaning apart from an independent knowledge 
of the history of the soil. With this knowledge the results are interest- 
ing, but in its absence are of little use except in extreme cases. 

The results obtained by citric acid, however, are strikingly instruc- 
tive and consistent. To illustrate this, it may be stated that the ratio 
of the average quantity of hydrochloric acid soluble potash in the sur- 
face soil of three potash-dressed plots to the average quantity foimd in 
seven plots not dressed with potash was 1*20 : 1. The citric acid 
soluble potash ratio, however, was 6*75 : 1. The plots dressed with 
dung for fifty years and nine years respectively gave, as compared with 
the same seven non-potash plots, hydrochloric acid soluble potash ratios 
of 1*27 : 1 and 1-23 : 1, while the citric acid soluble potash ratios were 
10-67 ; I and 917 : 1. 

Probably when a soil in the surface depth contains as much as 0*01 
per cent, of citric acid soluble potash, the special application of potas- 
sium salts is not needed. 

The largest accumulation of unused manurial potiish, whether applied 
as dung or as potassium salts, is in the surface soil ; but a large pro- 
portion is also found by citric acid in the second and even in the third 
9 inches. The subsoil accumulation is most evident in the dunged 
plots, and on the plot : which, in addition to potassium salts, has 
received superphosphate with sodium and magnesium sulphates, but 
without nitrogen (abundant supply and small utilisation). Both 
sodium and magnesium salts, in presence of phosphates and nitrogen, 
have exercised a distinct influence in increasing the proportion of citric 
acid soluble potash in all depths on the plots on which no potash has 
been applied for fifty years, and which still maintain a higher yield of 
potash in their crops than that given by the plot with superphosphate 
and ammonium salts alone, though the equivalent of the potash added 
originally has been practically exhausted. Furthermore, sodium and 
magnesium salts, used in conjimction with potassium salts, have caused 
a larger retention of potash in a citric acid soluble condition than when 
potash has been applied without them, although the potash yielded in 
the crops has been greater under the influence of the other alkalies 
alluded to. 

It is usually supposed that potash is pretty fairly retained by the 
surface soil of land containing, like the Kothamsted land, a fair ^ro- 



14 Proceedings, Fehncary 7, 1901. 

portion of clay. That thid is the case, as compared with sodium salts, 
is beyond doubt (see paper by the late Dr. A. Voelcker, " On the Com- 
position of the Waters of Land Drainage," 'Journal of the Royal 
Agricultiu*al Society of England,' 1874); but the series of analyses of 
the Broadbalk subsoils that has now been made by means of weak 
citric acid solution, shows that potash, though " fixed " relatively to 
soda, is far more migratory than phosphoric acid, and descends much 
lower into the subsoil. At the same time it appears probable that a 
portion of it passes into a fixed and stable form of combination, from 
which weak citric acid fails to dislodge it. 

The results yielded by the samples of soil and subsoil taken from 
the same plots at the diiferent periods afford instructive comparisons, 
notwithstanding the age of the earlier samples at the time of their 
examination, which might have been expected to be responsible for 
considerable modifications in the condition of the less stable chemical 
compounds contained in them. 



In consequence of the death of Her Most Gracious Majesty Queen 
Victoria, which took place on the 22nd of January, the meetings 
of the Society were suspended, by order of the President, until after 
the funeral of Her late Majesty, which took place on the 2nd 
February. 

February 7, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, in the Chair. 

The President, in moving that a dutiful Address of Condolence 
and Homage be drawn up and presented by the Council of the Society 
to His Most Gracious Majesty the King, said : — 

" The crape upon our Mace would remind us, if indeed we needed to 
be reminded, of the sorrow which is uppermost in every heart. We 
mourn to-day the greatest Queen the world has known — truly great by 
the supreme example She set, in Her own person, of sustained nobility of 
piu^ose, and of devotion to duty, and by the influence of Her wise and 
understanding heart, for the world*s good, upon the councils of the 
Empire. We mourn more than a great Queen— a gracious Lady who 
by the brightness of Her domestic virtues, and Her rare power of kindly 
sympathy with Her subjects in all their joys and sorrows, had in a 
real sense become the Mother of Her Peoples. As Fellows of this 
Society, we mourn further a Sovereign Patron, who by Her enlightened 
encouragement and protection, has made possible through the sixty- 



Proceedings and List of Papers read, 15 

three years of Her reign, an * improvement of natural knowledge,' not 
only unprecedented, but even beyond the wildest dreams of the most 
enthusiastic of the Fellows who welcomed Her at Her accession — so 
much so, indeed, that the Vidorian Age has become synonymous with 
ihe Scientific Age, 

" But, though dead She yet speaketh to us through His Gracious 
Majesty the King, Her Son, a Follow of this Society, whose words 
of yesterday are still in our ears, *that it would be his constant 
endeavour to walk in Her footsteps/ We join in most loyal and 
heartfelt wishes that His Majesty may long reign over a united and 
prosperous Empire; and that under His fostering care Science may 
continue to advance with even accelerated steps." 

The motion was seconded by Lord Lister and carried in silence, the 
Fellows present rising from their seats. 

A List of the Presents received was laid on the table, and thanks 
ordered for them. 

The following Papers were read : — 

'' The Boiling Point of Liquid Hydrogen, determined by Hydrogen 
and Helium Gas Thermometers." By Professor Dewar, F.R.S. 

*' On the Brightness of the Corona of January 22, 1898. Preliminary 
Note." By Professor H. H. Turner, F.R.S. 

" Preliminary Determination of the Wave-lengths of the Hydrogen 
Lines, derived from Photographs taken at Ovar at the Eclipse of 
the Sun, May 28, 1900." By F. W. Dyson. Communicated by 
the Astronomer Royal, F.R.S. 

" Investigations on the Abnormal Outgrowths or Intumescences on 
Hibiscus vUifolius, Linn. : a Study in Experimental Plant Patholo- 
logy." By Miss E. Dale. Communicated by Professor Marshall 
Ward, F.R.S. 

" On the Proteid Reaction of Adamkiewicz, with Contributions to the 
Chemistry of Glyoxylic Acid." By F. G. Hopkins and Sydney 
W. Cole. Communicated by Dr. Langley, F.R.S. 

** The Integration of the Equations of Propagation of Electric Waves." 
By Professor Love, F.R.S. 



16 Miss E, Dale. On the Ahiormal Ouigrov:ths or 



'' Further Investigations on the Abnormal Outgrowths or Intu- 
mescences in HibisctLs viti/oUm, Linn. : a Study in Experi- 
mental Plant Tathology." By Elizabeth Dale. Communi- 
cated by Professor H. Marshall Wakd, F.RS. Eeceived 
November 22, 1900,— Read February 7, 1901. 

(Abstract.) 

During the summer of 1899 some preliminary experiments were 
made in order to investigate the conditions determining the formation 
of certain outgrowths of which the structure had previously been 
examined.* Those outgrowths consist chiefly of greatly enlarged and 
multiplied epidermal cells, with very thin walls ; but the underlying 
parenchyma is often also affected. The cells concerned always lie 
immediately around a stoma, so that the guard-cells are lifted up as 
the outgrowth developes. The distribution of the outgrowths is there- 
fore dependent upon that of the stomata, and they are pathological in 
origin and nature. 

This year (1900) further experiments have been undertiiken, which 
eonfirm and extend the conclusions suggested by the earlier work, and 
which show that we have here a clear case of a pathological pheno- 
menon brought imder control. 

The plants used were chiefly Hibi.<ru.s vitifoliu.% but some observa- 
tions were also made on Ipomeii JFootlii. 

The experiments were designed to test the effects of moisture and 
light in inducing the formation of the intumescences, but they also 
served to show the influence of temperature. Most of them were 
made in the open air, as the outgrowths always arise on plants growing 
in a greenhouse. 

- I. In order to test the effects of moisture in the <air and in the soil, 
plants were kept with their shoots in dry or moist air, and their roots 
in dry or damp soil. Various combinations of dry or damp air or soil 
were used, with the result that outgrowths were always formed in 
damp air (provided there was suflBcient light and heat), whereas damp 
soil had no efiect. 

II. The eff'ects of light were tested by growing plants in white light 
of varied intensity, and under glass of different colours. Outgrowths 
were developed under clear and whitewashed glass, and under red 
and yellow glass, but not under blue or green glass, nor in poor light, 
and never in darkness. 

III. Observations as to the influence of temperature showed that, 

• Dale, " On Certain Outgrowths (Intumescences) on the Green Farts of 
Hibiscus vitifoUus, Linn.," ' Proc. Camb. Phil. Soc.,' vol. 10, Part 4. 



Intumescences in Hibiscus vitifolius, Linn, 



17 



given the other necessary conditions, the formation of outgrowths is 
promoted by heat. 

Large outgrowths may be artifically induced with certainty in about 
two days on a single healthy branch (still attached to the plant), by 
isolating it in a damp atmosphere, and exposing it to a strong light at 
a high temperature. 

The following is a brief summary of the principal experiments and 
conclusions : — 

Eftects of Moisture. 



Number 
of experi- 
ment. 



Conditions of 
experiment. 



1 
la 

lb 

2a 

2h 
3a 

Zh 

3c 
4 

5 

6 

7a 



lb 
7e 



Shoot in open air ; root, in 
moderately damp soil 

Shoot in air of greenhouse ; 
root in -wet, undrained 
soU 



Shoot in open air ; root in 
wet, imdrained soil 



Sbuot in air of greenhouse ; 

root in damp, undrained 

soil 
Shoot in open air ; root in 

damp, drained soil 
Shoot in air of greenhouse ; 

root in damp, drained 

soil 
Shoot in damp air ; root in 

damp, drained soil 

«» »» »» 

Shoot in damp air : root in 

drjr soil 
Shoot in dry air ; root in 

dry soil 
Shoot in Tery dry air; 

root in dry soil 
One shoot (attached to 
the plant) isolated in 
damp air 



One shoot (attached to 
plant) isolated in water 



Result. 



No outgrowths 

formed 
Outgrowths 

formed 



No outgrowths 
formed 



Outgrowths 
formed 

No outgrowths 

formed 
Outgrowths 

formed 



No outgrowths 
formed 



Many out- 
growths, on 
the isolated 
shoot only 

»> j> 

A few out- 
growths, on 
the isolated 
branch only 

No outgrowths 
formed 



Hemarks. 



Growth rapid and plant 
very healthy. 

The leaves soon drop- 
ped off, and the plant 
ultimately died, after 
experiment was stop- 
ped. 

Leaves dropped off, but 
the plant recovered 
when experiment was 
stopped. 



Leaves became yellow 
and curled under. 



Growth retarded. 



In bright sunlight and 
hot weather. 



In cool, almost sunless 
weather. 



VOL. LXVIIL 



18 Abnormal OxUgroivtlia or IiUumcscences in Hibiscus vitifoliiis. 

Effects of Light. 



Number I 

of expori- | 

ment. I 



10a 
106 



11 



12a 
126 



13 
14 



15a 



lob 



Conditions of 
experiment. 



I 



Poor light ; no sun . 



Light passing through 
I yellow glass 
I Light passing through a 
, solution of potassium 
I chromate 

; Ligl.t passing through red 
I glass 

i Light passing through 
blue glass 
Light passing through a 
solution of copper sul- 
phate and ammonia 
I Light passing through 
I gre3n glass 
Light passing through 

whitewashed glass 
Plant in darkness in a 

greenhouse 
Plant in darkness under a 
zinc cylinder in the open 



Result. 


Remarks. 


No outgrowths 
formed 




Outgrowths 
formed 




}i >» 




M )> 




No outgrowths 
formed 




)* ») 




»» »i 

Outgrowths 
formed 




No outgrowths 
formed 




n n 





Effects of Temperature. 

The formation of outgrowths (provided there is adequate moisture and light) is 
promoted by a high temperature. 

The conclusions drawn from the above experiments are, that the 
outgrowths are formed in a moist atmosphere, provided that there is 
also adequate light and heat. 

The immediate effect of the damp atmosphere is to check transpira- 
tion. This, in its turn, by blocking the tissues with water, disturbs 
the normal course of metabolism, and so leads (when the light and 
heat are sufficient) to changes in the metabolic activity of the plant, as 
is shown by the following facts : — 

1. The outgi-owths only develop if transpiration is reduced. 

2. The outgrowths are chiefly formed on organs which are actively 

assimilating, e.g.^ imder ordinary, red or yellow glass ; but only 
if transpiratory activity is lowered : they are not formed iu 
the open. 

3. They only occur (ceteris paribus) in plants in which there is an 

accumulation of starch. 

4. They are formed under clear glass and under red and yellow 

glass, but* not imder blue or green glass, and in no case in 
darkness. 



EquatioTUi of Propa/fatioii of Electi-ic Waves, 19 

5. Their formation is accompanied by the production of oil, which is 

not found in normal leaves. 

6. The presence of this oil suggests that events similar to those 

occurring in succulent plants are taking place, viz., reduced 
respiration and the development of osmotically active substances 
in excess. 

7. It is therefore probable that the intumescences are due to the 

local accumulation of osmotically active substances, produced 
under the abnormal conditions, viz., reduced transpiration 
and consequent lack of minerals, while carbohydrates are being 
developed in excess. 



** The Integration of the Equations of Propagation of Electric 
Waves." By A. E H. Love, F.R.S. Eeceived December 29, 
1900,— Eead February 7, 1901. 

(Abstract.) 

The equations of propagation of electric waves, through a dielectric 
medium, involve two vector quantities, which may be taken to be the 
electric force and the magnetic force ; and they express the rate of 
change, per unit of time, of either vector, in terms of the local values 
of the other. Various forms may be given to the equations, notably, 
that employed by Larmor, in which the magnetic force is regarded as 
H velocity, and the electric force as the corresponding rotation. In 
this form there is one fundamental vector, viz., the displacement 
corresponding to the magnetic force, regarded as a velocity ; and this 
displacement-vector may, in turn, be derived from a vector potential. 
Every one of the vectors in question is circuital ; and the several 
components of them satisfy the partial differential equation of wave 
propagation, viz., <j!> = c^V'^<f>y c being the velocity of radiation. 

One way of integrating the equations is to seek particular systems 
of functions of the co-ordinates and the time, which, being substituted 
for the components of the vectors, satisfy the equations ; more general 
solutions can be deduced by synthesis of such particular solutions. 
Owing to the circuital relations, certain known solutions of the partial 
differential equation of wave propagation are not available, for represent- 
ing the components of the vectors. A very general system of parti- 
cular solutions, which are available for this purpose, is obtained. These 
particular solutions are expressed in terms of spherical harmonics and 
arbitrary functions of the time ; and they can be regarded as generali- 
sations of others, given by Lamb, which depend in the same way upon 
spherical harmonics, and contain simple harmonic functions of the time. 
By means of them, we can describej two types of sources of electric 



20 Equations of Propagation of Electric Waves, 

radiation : — The sources of one type are similar to infinitesimal Hertzianr 
vibrators, being related in the same way to an axis, but the dependence 
of the emitted radiation on time is arbitrary ; the sources of the other 
type are obtained therefrom by interchanging the rdles of the electric 
and magnetic forces. 

Another way of integrating the equations is to seek to express the 
values of the vectors, at one place and time, in terms of their values, 
at other places and times. The model for all investigations of this 
kind is Green's Theory of the Potential. The main steps are (1) the 
determination of particular solutions, which tend to become infinite, in 
definite ways, in the neighbourhood of chosen points ; (2) the discovery 
of a theorem of reciprocity, connecting the values, on any chosen 
surfaces, of two sets of solutions ; (3) the determination of the Umiting; 
form, assumed by the theorem of reciprocity, when the sohitioiui of one^ 
system have the assigned character of infinity at a given point. The 
result is the expression of the values of the functions of the other 
system, at that point, and at a chosen instant of time, in terms of their 
values, at all points on an arbitrary siu^ace, and at determinate instants 
of time. In the present theory, the solutions required for the first step 
are among those alread}^ found ; the theorem of reciprocity is obtained 
by a modification of the process by which the fundamental equations 
can be deduced from the Action principle ; and the limiting form of the 
theorem is found by adapting a process due to Kirchhoff. The result 
is that the radiation which arrives at a chosen point may be regarded 
as due to a distribution of imagined sources of radiation upon aw 
arbitrary closed surface, separating the point from all the actual sources 
of radiation. The imagined sources are of the two types previously 
specified ; and the directions of their axes, and the intensities of the 
radiation sent out from them, are determined simply and directly by 
the values, on the surface, of the vectors involved in the propagation 
of the waves. A method for replacing the imagined sources of either 
type by soiu-ces of the other type is indicated. The general theorem 
is verified by choosing, for the arbitrary surface and the point, a sphere 
and its centre; it then becomes equivalent to Poisson's well-known 
solution of the differential equation of wave propagation in terms of 
initial values. The " law of disturbance in secondary waves," to which 
the theorem would give rise, is also determined ; it is, in essentials, 
the same as has been found by previous writers. 

The general theorem is applied to the problem of the passage of 
radiation through an aperture. When a train of radiation comes to a 
perforated screen, or when electric \'ibrations take place in the dielectric 
on one side (the nearer side) of a conducting surface, in which there is 
an aperture, waves are sent out into the medium on the farther side ; 
but the aperture also has the effect of generating a system of standing 
waves on the nearer side. These systems of waves become, to a great 



On the Proteid Reaction of Adamkiewicz, &c. 21 

extent, determinate, if we combine with the general theorem the condi- 
tions of continuity of state of the dielectric on the two sides of the 
aperture. The determination is practically complete when the medium 
on the nearer side is the dielectric plate of a condenser, in which 
electric vibrations are taking place ; and the result can be applied to 
determine the rat« of decay of the vibrations due to transference of 
the energy to the external dielectric. The example of a condenser, 
with concentric spherical conducting surfaces, the outer conducting 
sheet being perforated by a small circular aperture, is worked out in 
detail ; and the results suggest that the maintenance of the vibrations 
depends on the screening action of the outer conductor rather than 
on the largeness of the capacity of the condenser ; in fact, the vibra- 
tions of the spherical condenser are much more slowly damped when 
the capacity of the condenser is small than when it is large, the outer 
conductor and the aperture remaining the same. 



'* On the Proteid Reaction of Adamkiewicz, with Contributions to» 
the Chemistry of Glyoxylic Acid." By F. Gowland 
Hopkins, M.A., M.B., University Lecturer in Chemical 
Physiology, and Sydney W. Cole, B.A., Trinity College. 
(From the Physiological Laboratories, Cambridge.) Commu- 
nicated by Dr. Langley, F.E.S. Eeceived January 7, — Read 
February 7. 1901. 

In 1874 Adamkiewicz* described the now familiar reaction which 
results in the production of a violet colour when strong sulphuric acid 
is added to the solution of a proteid in glacial acetic acid. Adam- 
kiewicz did not apparently look upon the employment of the acetic 
acid as introducing anything beyond a certain modification of the 
action of sulphuric acid. His original communication opens with a 
description of the colour phenomena seen when egg-white is dissolved 
in strong sulphuric acid : and he begins the description of this reac- 
tion, since associated with his name, by speaking of " a special influence 
which the presence of glacial acetic acid has upon the colour of the 
sulphuric acid proteid solution." The view has since been generally 
held that the coloured product of the reaction arises entirely from the 
proteid molecule itself, as the result of an interaction between pre- 
cursors liberated under the influence of the strong acids employed. 

V. Udranszkyt believed that the colour change which occurs is, as a 
matter of fact, to be classed as a furfurol reaction. It is therefore to 
be compared with the result of such a procedure as that of Molisch*s 

• * Pflager's Archly,* 1874, vol. 9, p. 156. 

t * 55eitsch. f. physiol. Chem.,* 188S, toI. 12, p. 395. 



22 Messrs. F. G. Hopkins and S. W. Cole. 

test, in which ^-naphthol and snlphuric acid are added to a proteid 
solution. AVhile in the latter the added naphthol is held to react with 
furfurol from the proteid ; in the Adamkiewicz reaction both the fur- 
furol and a substance capaWe of reacting with it are supposed to he 
liberated from the proteid molecule. Such we l)elieve is the prevalent 
view. Of late years, the Adamkiewicz reaction has been much em- 
ployed as giving evidence for the presence of carl)ohydrate groups in 
certain proteid derivatives, and of its absence from others. More than 
one writer,* however, has referred to an element of uncertainty in the 
reaction, and it is easy to gather from the literature that this has been 
commonly observed.! 

In what follows it will be shown that the mechanism of the reaction 
has been wholly misunderstood. Proof will 1x5 given that the use of 
acetic acid introduces an extraneous and perfectly specific factor into 
the reaction, involving the addition of a substance quite necessary to 
the formation of the coloured product. This substance, moreover, is 
not acetic acid itself but an impurity, which, though very generally 
present, is admixed in varying quantity, and is occasionally absent. 

I. The Ueadioa due U) an Impurity in Acetir, Add, 

AVe were led to pursue the following investigation by observing that, 
with a specimen of acetic acid in use in this laboratory last year, it 
was impossible under any circumstances to obtain the Adamkiewicz 
reaction. 

No matter what form of proteid nnght be employed, when its solu- 
tion in this acetic acid was mixed with sulphuric acid, a yellow or 
brown, slightly fluorescent mixture was all that could be obtained. No 
modification in the order of the procediu*e, or in the proportion of the 
two acids employed, resulted in the production of any trace of red or 
^^olet colour. 

We afterwards obtained a number of specimens of acetic acid from 
various makers, and were surprised to find that no small proportion of 
these gave equally negative results ; while, of the remainder, some 
yielded a much more intense reaction than others, although employed 
under precisely similar conditions. 

Either, therefore, the negative result with particular specimens was 
due to the prescfiice of some impurity capable of interfering with the 
production of colour, or the reaction itself must be due to a sub- 
stance commonly, though not universally, present as an impurity in 
acetic acid. 

We soon obtained evidence that the latter alternative must be 
accepted. For we found that whenever a specimen of glacial acetic 

• Cf, Halliburton, * Schaf^r's Text Book of Physiology/ vol. 1, p. 47. 
t Cf. Salkow:*ki, * Zeitech. f. plirsiol. Cliem.,' vol. 12, pp. 220, 222. 



Oil the Proteid Bcaction of Adamkieicicz, &c. 23 

acid \nelding a positive result is partially crystallised by freezing, the 
power to yield the reaction is diminished in the crystals and increased 
in the mother liquor. It is possible indeed, by repeated recrystallisa- 
tion, to obtain glacial acid wholly incapable of giving the reaction. 

Much more readily, however, is the reactive substance to be con- 
centrated by distillation. Any specimen of glacial acetic acid, if dis- 
tilled, will yield the whole of any chromogenic substance it may contain 
in the first runnings. After concentration to about half-bulk — more or 
less according to the proportion of reactive substance originally present 
— the residue will yield no trace of red or violet colour when mixed 
\vith proteid and sulphuric acid ; while, on the other hand, the distil- 
late twice or thrice fractionated yields the reaction with greatly in- 
creased intensity.* 

It is easy to understand, therefore, why different specimens of acetic 
acid obtained in the market yield the reaction Avith different degrees of 
intensity, as this will depend upon the stage at which they were col- 
lected during distillation in bulk. It is also clear why the reaction has 
been looked upon by different observers as an uncertain one. 

The accepted view, that the colour phenomenon is due to the inter- 
action of two chromogenic groups, both derived from the proteid 
molecule under the action of the mixed sulphiuric and acetic acids, is 
certainly erroneous. One factor necessary to the reaction is supplied 
by a substance admixed with the acetic acid. That it is in no sense a 
fnrfiu-ol reaction is indicated by the fact that the addition of furfurol 
confers no power of yielding the colour with proteid upon a specimen 
of acetic acid previously without it ; and, on the other hand, when 
furfurol is added to acetic acid containing the chromogenic substance 
in abundance, there is equally a complete absence of the reaction upon 
mixing with strong sulphiu'ic acid. 

II. Xatnre of the Suhstanre responsible fm- the Reaction. 

Our earlier attempts actually to isolate the active substance from 
acetic acid by fractional distillation were unsuccessful ; and, having 
regard to the fact that, in a reagent so familiar as acetic acid, no admix- 
ture could well have been hitherto overlooked unless the substances were 
present in very small amount, we determined to seek first for indirect 
evidence, such as might give at least some indication as to the kind of 
substance we had to deal with. 

To this end we set out to add to acetic acid, previously deprived by 
distillation of its chromogenic admixture, various compounds of typic^il 
constitution, in the hope that we might find among these some that 
would yield at least an analogous reaction. 

• This applies to glacisl acid ; with dilute acid of lower boiling point, concentra- 
tion of the product by distillation is less easy. . 



24 Messrs. F. G. Hopkins and S. W. Cole. 

Wholly negative results were obtained with various homologous 
fatty acids ; with formic, acetic, and propionic aldehydes ; with acetone, 
and with various ethereal acetates and other esters. 

But, during this preliminary stage of our investigation, the interest- 
ing observation was made that formic acid, prepared from pure glycerin 
and pure oxalic acid, and used instead of acetic acid imder the ordinary 
conditions necessary for the reaction, may yield the colour in a per- 
fectly typical manner; the spectroscopic absorption of the product 
obtained being identical with that seen when acetic acid is used. But 
from tEe fonnic no less than from acetic acid, the chromogenic sub- 
stance may be distilled off, appearing alwaj'^s in the earlier portions of 
the distillates, and leaving the remainder of the formic acid to yield 
ivholly negative results. 

This result — the explanation of which becomes clear in the sequel — 
appeared to limit somewhat the ground we had to traverse in our 
search. 

A further and still more definite limitation came to light when we 
found that the reactive substance in acetic acid is not an impurity of 
wholly extraneous origin, but is a derivative of acetic acid itself. 
When a quantity of acetic acid wholly free from the reactive sub- 
stance has stood for a few weeks, a reaction may always be obtained 
once more from the earliest portions of a distillate ; and, after stand- 
ing for a month or two, even the bulk may yield a colour of moderate 
intensity. (Cf, infra,) 

When, again, a pure acetate, and especially calcium acetate, is 
distilled with excess of sulphuric acid, the first runnings always give a 
marked Adamkiewicz reaction, though later portions give none. This 
is true even when the acetate has been made by neutralising acid which 
was itself wholly incapable of giving a reaction. 

Lastly, among the products of the dry distillation of most acetates 
small quantities of a substance are foiuid which react with proteid in a 
typical manner. In the case of calcium acetate the reaction obtainable 
is a marked one — though, as stated above, the active substance is 
certainly not acetone — while with an aqueous extract of the products 
of the dry decomposition of mercuric (not mercurous) acetate the 
reaction with proteid is intense. 

With such indications as these facts afforded, we now fortunately 
elected to experiment with various two-carbon compounds of typical 
structure, such as might conceivably arise from acetic acid, by oxidation 
or otherwise. 

The first positive evidence came to light when we set out to prepare 

gly collie aldehyde by Teuton's method.* As a mere preliminary 

observation, we oxidised tartaric acid in solution, by means of peroxide 

of hydrogen in the presence of a little ferrous sulphate, without taking 

* * Journ. Chera. Soc.,' 1895, vol. 67, p. 778. 



On the Proteid Reaction of Adamkiewicz, &c, 25 

especial care to keep the mixture at 0"*, and without attempting to 
separate the dioxjmialeic acid formed. A little of the oxidised solution 
was heated direct on the water bath till all evolution of C0> had 
•ceased, and then cooled. A trace of Witte's peptone was added to the 
solution, which was free from excess of peroxide, and then strong 
mdphuric acid. An intense colour reaction was obtained exactly 
similar to that seen in a noimal Adamkiewicz reaction when carried 
out with acetic acid rich in the chromogenic substance. The solution 
gave also in the spectroscope an exactly similar absorption band. 

We found subsequently, however, that glycoUic aldehyde, isolated, 
either in the syrupy or crystalline condition,* and whether in aqueous 
or acetic acid solution, gave no colour reaction under like conditions, 
but yielded only a charred product when the sulphuric acid was added. 
Moreover, acetic acid, however rich in the chromogenic substance, 
never reduces (after neutralising) alkaline copper solutions, A reduc- 
tion of ammoniacal silver solutions may be obtained, but never any 
effect upon Fehling's solution. 

We came to the conclusion, therefore, that the substance sought 
must be an oxidation product of glycoUic aldehyde; and we now 
found that the latter needs only to be treated by Fenton's oxidation 
method carried out at the temperature of the water bath to give a 
product, which, when free from excess of peroxide, yields in acetic or 
aqueous solution the proteid reaction abundantly. 

At this time we made another observation of the greatest assistance 
to our inquiry, finding that the chromogenic substance is produced in 
abundance when oxalic acid is reduced in aqueous solution by means 
of zinc and sulphuric acid, or, more conveniently, by sodiiun amalgam. 

The reduction need last for a few minutes only, and a little of the 
solution, without further treatment, will then be found to give an 
intense colour with proteid and sulphuric acid, the product showing 
spectroscopic appearances identical with those of the ordinary Adam- 
kiewicz reaction. 

There was now no doubt that a colour reaction, not to be dis- 
tinguished from that of Adamkiewicz, is yielded by a substance which 
is at once an oxidation product of glycollic aldehyde and a reduction 
product of oxalic acid. It was difficiilt to see how this substance could 
be other than glycollic acid, glyoxylic acid, or glyoxal. 

Pure glycollic acid was obtained from Merck. It gave no trace of a 
colour reaction with proteid solution and sulphuric acid. The product 
of its oxidation by Fenton's method reacted, however, in a perfectly 
typical manner, and Fenton and Jones have found that this product is 
glyoxylic acid. 

The latter was therefore prepared from alcohol by the method of 

• Fenton and Jackson, * Joum. Chem. Soc./ vol. 75, p. 576, 1899. We wero 
indebted to Mr. Hj. Jackson for a supply of the crystalline aldehjde. 



26 Messrs. F. G. Hopkins and S. W. Cole. 

Debus. The calcium glyoxylate first obtained was recrystallised 
thrice. A minute crystal of the salt dissolved in water, together with 
a little proteid, gave, upon the addition of strong sulphuric acid, a 
vivid colour reaction not to be distinguished, spectroscopically or other' 
wise, from the reaction of Adamkiewicz. 

Glyoxal, prepared subsequently from the products of the same 
Debus oxidation, gave no trace of such a reaction.* When glyoxylic 
acid is added to glacial acetic acid, previously deprived of its chromo- 
genic power by distillation,' further distillation now yields a distillate 
which reacts typically, and the glyoxylic acid -comes over charac- 
teristically, like the original chromogenic substance in the earlier 
fractions. 

III. Glj/oxi/lic Acid from Acetic Acid. 

It now became necessary to ascertain whether glyoxylic acid is, as a 
matter of fact, present in such specimens of acetic acid as yield the 
Adamkiewicz reaction. 

In seeking for evidence as to this, it was necessary to remember that 
exceedingly little glyoxylic acid is necessary ^o the reaction. With an 
aqueous solution of such strength as will give no more than an 
opalescence T\nth phenyl hydrazine, the coloiu* reaction with proteid is 
well marked. 

It was found, however, that oxidation with hydrogen peroxide 
confers abundant chromogenic power upon acetic acid previously giving 
no proteid reaction ; and it was our first endeavour to ascertain whether, 
as a result of this, glyoxylic acid is produced in quantity sufficient for 
its easier identification. 

The presence of small quantities of ferrous iron accelerates the 
oxidation, and is, perhaps, essential to it.t The process occiu^ most 
rapidly at boiling temperature, and proceeds most satisfactorily when 
the acetic acid is repeatedly distilled with the peroxide. The limit of 
the oxidation is in any case soon reached. Using twenty volumes 
strength, the peroxide is found to be rapidly destroyed till a volume 
has been added about equal to that of the acetic acid taken ; after this 
the reaction becomes very slow. 

AVe proceeded as follows : — A litre of glacial acetic acid was mixed 
with an equal bulk of twenty-volume peroxide and some ammonio 
ferrous sulphate added (half a gramme per litre, or less). The mixture 

* Many specimens of commercial glroxal give the reaction, but onlj, as ve 
haTP found, when they contain glyoxylic acid ; preparations of glycollic acid may 
contain traces of the latter. 

t We hare found that some specimens of peroxide bring about the oxidation 
■without the addition of iron ; others undoubtedly act much less readily, unlets a 
ferrous salt is added. While we have been unable to detect the presence of iron 
in the former, so small a quantity appears to affect the reaction that it is possible a 
tiace of the metal present as an impurity may account fur the difference. 



was hlowjy (listill(Ml iic;ii-ly to dryness, and tli'.' <listillal(' rcliirnrd and 
again distilled. The second or third distillate usually showed freedom 
from peroxide when te8ted with chromic acid ; if not, distillation was 
repeated. 

One-tenth of the final distillate was set aside, and the remainder 
neutralised with potash. The still acid portion being then mixed with 
the rest, the whole was distilled as low as possible, avoiding, however, 
any separation of potassium acetate in the retort. The distillate 
always gave an abundant proteid reaction, and if any trace of free 
peroxide had been left at the previous stage, it always disappeared 
during the distillation of the partially neutralised mixture as just 
described. A small trace of free peroxide will interfere with the 
proteid reaction. On adding phenyl hydrazine hydrochloride (without 
acetate) to the distillate thus obtained, a light yellow precipitate 
begins to separate almost at once, and after standing it becomes con- 
siderable in amount, and is crystalline. But although, as we were able 
to show, the hydrazone of glyoxylic acid is present in this precipitate, 
it is mixed with a considerable proportion of a compound much less 
soluble in acetic ether and in hot water. If the original precipitate be 
recrystallised from a minimal quantity of acetic ether, the substance 
which separates first consists of perfectly colourless glistening plates, 
which after recrystallising from acetic ether may assume the form of 
resetted prismatic needles. These melt sharply at 184*". 

The nature of this substance became clear after the publication of 
certain recent observations. Gerhard Ollendorff has shown that 
formic aldehyde is formed when glycollic acid is oxidised with per- 
oxide of hydrogen, and Fen ton* calls attention to the fact that gly- 
oxylic acid must in this case be the intermediate product. The 
product we obtained from acetic acid was undoubtedly the compound 
of formaldehyde described by Wellington and Tollens.t 

A portion repeatedly recrystallised from acetic ether and showing a 
constant melting point (IS^*") was analysed. 

0*147 gramme gave 27*4 c.c. moist N, at 12^ and 758 mm. N = 
22-07 per cent. 

Another preparation, recrystallised from a mixture of alcohol and 
toluol, melted at 182—183"; of this 

0-211 gramme gave 39*3 c.c. moist N, at 14°, and 758 mm. N = 
21-87 per cent. 







Calculated for 


I. 


II. 


C,jir,gN4. 


22-07 


21-87 


22-22 



This hydrazone can be obtained pure in the above manner with 

• Fenton, ' Journ. Chem. Soc.,' ]900, toI. 77, p. 129C. 
t * Dentoch. Chem. Oca. Bericlite,' 18S5, vol. 18, p. 3330. 



28 Messrs. F. G. Hopkins and S. W. Cole. 

great ease if not more than 4 to 5 grammes of phenylhydrazine hydro- 
chloride have been added to the final di8tillate/)btaincd after oxidising, 
as above, 1 litre of acetic acid, nearly neutralising the mixture and 
distilling. We prepared the compound from formaldehyde, and found 
it to agree with our product in every particular. 

Formaldehyde certainly does not yield the proteid reaction, and its 
formation when acetic acid is treated as described seems to be in itself 
evidence for the formation of glyoxylic acid during the process, as it 
is difficult to see how it could arise during the oxidation of acetic acid 
if not from a preliminary formation of glyoxylic acid with subsequent 
loss of carbon dioxide. 

But its formation adds greatly to the difficulty of obtaining pure 
the hydrazone of glyoxylic acid itself, especially as the precipitate 
produced by phenylhydrazine undoubtedly contains, in addition to the 
compound of Wellington and Tollens, smaller amounts of the deriva- 
tives described by J, W. Walker.* 

After the nature of this bye-product was recognised we modified our 
procedure by neglecting the earlier portions of the final distillate 
which contains, of course, the greater part of the formaldehyde. 
Phenylhydrazine hydrochloride added to the latter half, or two-thirds, 
of such a distillate yields a precipitate which forms more slowly than 
that obtained when the whole is dealt with. After twenty-four hours 
it is usually crystalline and of a yellow colour, growing darker with 
further standing. 

We found it easier to obtain a product with a constant melting 
point by recrystallising from hot water rather than from an organic 
solvent, prolonged heating with the water being at any stage avoided. 
This treatment involves considerable loss, however, and we obtained 
only about 4 decigrammes of the hydrazone after oxidising 3 litres of 
acetic acid. This, however, had all the characters of glyoxylic 
hydrazone, and melted sharply at 137°. 

0*204 gramme gave 30*4 c.c. moist N at 16"* and 750 mm. N = 
17-14 per cent. Calculated for CgHgOiNo = 17-07. 

When acetic acid has been oxidised as described and the mixture 
partially neutralised and distilled, the distillate, when treated with 
excess of chalk, will yield, after standing and filtering, the reaction for 
glyoxylic acid described by Perkin and Duppa. If after treatment 
with chalk a slight excess of calcium hydrate be added, and the mix- 
ture concentrated in mcuo to about one-third its original bulk, this 
reaction with aniline oxalate is obtained in a highly characteristic 
manner. 

The methods we have hitherto employed do not yield the glyoxylic 
acid in solutions of sufficient strength to permit of its calcium salt 

• ' Journ. Chcm. Soc.,' 1896, vol. C9, p. 1280. 



On the Froteid Reaction of AJamkiewicz, &c. 29 

being separated from the associated acetate and isolated in snbstance. 
The ease with which the salt dissociates and the volatility of the acid 
with water vapour make concentration of small avail. 

The evidence for the formation of glyoxylic acid during oxidation 
appears, however, to be conclusive, and it is interesting to note that, 
judging from the gradual development of the reaction with proteid, 
this oxidation goes on slowly when acetic acid is exposed to air, and 
especially under the influence of light. Ferrous iron undoubtedly 
accelerates this, and if acetic acid giving no proteid reaction be some- 
what diluted, and a little ferrous salt added, exposure to direct sun- 
light will confer a reactive power in the course of a few hours. 

We have not been able to separate the hydrazone in quantity sufh- 
cient for its identification from average specimens of untreated acetic 
acid ; but it appears equally difficult to do so when small quantities of 
glyoxylic acid, sufficient to confer an average chromogenic power, have 
been added to a specimen previously giving no reaction. 

On one occasion we obtained a quantity of glacial acid giving the 
reaction with special intensity. This acid had crystallised in bulk, and 
we were supplied with drainings from the crystals. Seven litres were 
fractionally distilled imtil the chromogenic substance was concen- 
trated into about 1 litre. This was nearly neutralised and again dis- 
tilled. Phenylhydrazine acetate added to the distillate gave a con- 
siderable quantity of crystalline precipitate, yellow at first, darkening 
on standing. This was obtained before we had identified glyoxylic 
acid as the substance sought, and most of the hydrazone was lost in 
preliminary solubility tests. A small quantity was reserved, however, 
and this, recrystallised thrice from hot water, melted sharply at 137°. 

The observations we have hitherto made give no quantitative indica- 
tions of any value. In this paper we have been mainly concerned with 
the endeavour to prove the natiure of the active sul)stance in the 
proteid reaction. We propose to study the oxidation of acetic acid 
further, and to define if possible the conditions necessary for a maximal 
yield of glyoxylic acid. 

rV. Remarks on the Colour Reaction : Spectroscopic Phenomena. 

Adamkiewicz^ observed that the coloiu* produced in the reaction 
varies from red to violet, the blue element increasing with increase in 
the amount of acetic acid employed. When glyoxylic acid in aqueous 
solution is used, unless the solution be very dilute, the colour partakes 
more of a blue shade than is usually seen with ordinary specimens of 
acetic acid. But after concentrating the reactive substance of the 
latter by fractional distillation (supra) or upon large dilution of the 

• Xof. rtY., p. 158. 



30 Messrs. F. G. Hopkins and S. W. Cole. 

glyoxylic acid solution, the coloiu^s obtained become identical. The 
spectroscopic absorption is identical whichever reagent is employed. 

When siilphu]'ic acid is added to a solution of proteid in acetic acid 
wholly free from glyoxylic acid, a considerable amoimt of charring 
occurs, and the mixture becomes somewhat fluorescent. When, under 
similar circumstances, very little glyoxylic acid is present, the reddish 
colour obtained is still associated with fluorescence. But, when suffi- 
cient of the glyoxylic acid is present, whether in acetic or aqueous 
solution, to combine with the whole of the proteid product concerned 
in the reaction, there is complete absence of charring and little or no 
fluorescence. The solution becomes of a pure violet-blue colour. 

The coloured product of the Adamkiewicz reaction is usually stated 
to show an absorption band between b and F in the position of the 
lu'obilin band ; and Krukenberg described another between D and E. 
Salkowski found the former to be inconstant, and we are convinced 
that the latter alone is proper to the real product of the colour reac- 
tion : the former, when seen, being due to some accessory effect of the 
strong acids upon proteids. It is never seen in the original form <rf 
the reaction unless the acetic acid employed is greatly deficient in 
reactive power, and it is not ol^served with glyoxylic acid. The other 
band is always present, and is identical after the use of a satisfactory 
specimen of acetic acid and when a solution of glyoxylic acid is used. 

The band shrinks rapidly from its more refrangible edge on dilution 
of the solution, its redward edge shifting but little. 

The following readings show the correspondence seen after em[doy- 
ing acetic acid as obtained in the market (but with its active substance 
concentrated by distillation) and that seen after the use of glyoxyUc 
acid in aqueous solution. The strengths were so arranged that, before 
dilution, the colom* of each solution appeared to be of the same 
intensity. Witte's peptone was the proteid employed to obtain the 
reaction : — 

Aqueous ffljoxjlio 
Acetic acid. acid. 

Strong A480— A625 X 480— X 630 

Diluted with an equal 

volume of sulphuric acid A. 495 — A. 625 A. 495 — A 625 
Diluted with thrice its 

vohune of sulphuric acid A. 530— A 610 X 530— A 615 

V. Other Sourres of the Iteartive Substance, 

Of the typical two-carbon compounds — glycol, glycollic aldehyde, 
glycoUic acid, glyoxal, glyoxylic acid, and oxalic acid — none but the 
aldehyde-acid (glyoxylic acid, HCO.COOH or CH(0H)2.C0OH), gives 
the smallest indications of yielding a colour-reaction with proteid on 
addition of sulphuric acid. . It would seem that the reaction is not 



On the Proteid Reaction of Admnklewicz, &c. 31 

common to aldehyde-acicls, as glyciironic acid, HC0(CH.0H)4C00H, 
gives wholly negative results. Again, a ketonic acid so closely related 
to glyoxylic acid as pyruvic acid, CH3.CO.COOH, gives no indication 
of a reaction. 

Glyoxylic acid stands, of course, alone in containing the aldehydic 
and carboxylic groups in juxtaposition. Our observations are far 
from being complete enough to enable us to assert that a reaction with 
proteid of the special type under consideration depends essentially 
upon this particular structure. But the preliminary observations we 
have made tend to give some probability to this view. At least it 
may be said that hitherto we have never obtained a reaction except 
with products in which either glyoxylic acid has been shown to be 
present, or in which its presence is extremely probable. 

For instance, we have found that mesoxalic acid (prepared from 
barium alloxanate) in aqueous solution gives with proteid and sul- 
phuric acid a perfectly typical Adamkiewicz reaction ; but under the 
conditions employed we have found that a portion at least of the 
mesoxalic acid present loses carbon dioxide, so that it is in the highest 
degree probable that glyoxylic acid is in this case also the su]>stance 
which reacts. 

Pyruvic add gives, as we have said, no trace of a reaction, but the 
product of its oxidation by peroxide of hydrogen undoubtedly reacts. 
Paraladic acid, itself inactive, yields also an active product on oxida- 
tion by Fenton's method at the temperature of the water bath. These 
two cases go together, as Fenton and Jones have shown that lactic acid 
yields pyruvic acid when oxidised at 0" in the presence of ferrous iron. 
It seems extremely probable that the oxidation of the pyruvic acid at 
the higher temperature yields mesoxalic acid, and that the reaction 
obtained is therefore due in each case to glyoxylic acid. 

One abundant soiu'ce of a reactive substance is found in the oxida- 
tion of glycerin by Fenton's method, carried out at the temperature of 
the water bath. Glyceric acid yields the substance under like condi- 
tions ; and, as Fenton and Jones* have shown that glyceric acid, when 
the oxidation is carried out in the cold, gives a product which is almost 
certainly either hyd^oxy-pyru^^c acid or the tautomeric subsUince 
dihydroxyacrylic acid, the facts here quite probably fall into line with 
those just enumerated. The substance which reiicts with proteid is 
only obtained in quantity in these cases when the oxidation is carried 
out at higher temperatures than those used by Fenton, and if the 
oxidised products are distilled, it is always found that the distillate 
gives the reaction. 

When dextrose solutions are boiled with peroxide in the presence of 
ferrous salts a substance is formed, volatile with steam, which yields 

• ' Journ. Chem. Soc.,' 1900, vol. 77, p. 72. 



32 On the Proteid Reaction of Adamkiewicz, ^. 

the proteid reaction abundantly. Preliminary observations that we 
have made leave little doubt that this is glyoxylic acid itself. 

If it should prove that the reaction is, as a matter of fact, peculiar 
to glyoxylic acid, it certainly forms a very delicate test for that 
substance. 



VL Glyoxylic Add Solutions a Practical Test for Proteids. 

By replacing the acetic acid of the Adamkiewicz reaction by weak 
aqueous solutions of glyoxylic acid a very beautiful and reliable test 
for proteids is obtained. The coloiu* reaction is brilliant, and the test 
is, of course, subject to none of the uncertainty inseparable from the 
use of acetic acid.* 

In preparing such a test solution, there is usually no need to separate 
the glyoxylic acid from associated products. Excellent test solutions 
may be made by oxidising upon the water bath, in the presence of 
small quantities of ferrous iron, either weak solutions of tartaric add 
or mixtures of glycerin and water, great care being taken to ensure 
that no trace of free peroxide remains at the close of the operation. 
But we strongly recommend the use of reduced oxalic acid for the pur- 
pose, as a solution can be prepared with great ease, and almost without 
regard to conditions. In a moderately strong solution of oxalic acid & 
few lumps of sodium amalgam are placed, the amount taken of the 
latter being less than sufficient to neutralise the acid. WTien the 
evolution of hydrogen has ceased, the solution is poured off from the 
mercury and filtered. It will be found, even after large dilution, to 
yield an intense reaction with proteids if used instead of acetic acid 
under the familiar conditions of the Adamkiewicz test. The proteid, 
or the proteid solution to be tested, should be first added to the 
reagent, and then strong sulphuric acid poured down the side of the 
test-tube. The reaction may be first observed at the jimction of the 
fluids find the latter subsequently mixed. At least one-third volume 
of sulphuric acid should he used, but the quantity may be almost 
indefinitely increased. There is no tendency to charring. 



* It is certainly rare to find a specimen of acetic acid which jields no reaction, 
tbougli man J contain too little glyoxylic acid to give a satisfactory colour. It 
seems to be possible, LowcTcr, that there hare been cases of a proteid deriTative 
being found to yield no Adamkiewicz reaction, in which the negatire result wai 
really due to the acetic acid en\ployed. We have, for instance, prepared and 
carefully purified the primary albumoses from Witte's peptone by the method of 
E. F. Pick C Zeitsch. f . physiol. Chem./ 1899, toI. 28, p. 219). Unlike thia obMrrer, 
we hare found these products to yield a marked Adamkiewicz reaction ; tad with 
all reserve, we renture to suggest that the acetic acid employed by Pick at tluf 
stage of his observafions may hare chanced to be free from chromogenio power. 



Deteinnination of tlie Wave-lengths oftlie Hydrogen Lilies. 33 

Siimvianj. 

The proteid reaction described by Adamkiewicz is not a furfurol 
reaction, but depends upon the presence of small quantities of an 
impurity in the acetic acid employed. Some specimens of acetic acid 
yield no reaction, and all may be deprived of chromogenic power by 
distillation. 

The substance essential to the reaction is glyoxylic acid. 

Small quantities of glyoxylic acid are produced during the oxidation 
of acetic acid by hydrogen-peroxide in the presence of ferrous iron. 
Under the conditions used in this research, part of the glyoxylic acid 
thus formed is split up, yielding formaldehyde. 

Glyoxylic acid is slowly formed when acetic acid stands in the air, 
and more rapidly in the presence of ferrous iron and under the influence 
of direct sunlight. Most specimens of acetic acid contain small 
amounts of glyoxylic acid as an admixture. 

A dilute aqueous solution of glyoxylic acid, which may be readily 
prepared by the reduction of oxalic acid with sodium amalgam, forms 
an admirable test for proteids when used instead of acetic acid under 
the ordinary conditions of the Adamkiewicz test. 

In carrying but this investigation we have been led to employ 
extensively the method of oxidation described by H. J. H. Fenton, 
and as a result we have in some degree trenched upon the systematic 
study of the oxidation of organic acids which he has in hand. It is 
with his consent that such of our observations are published. 

The expenses of the research were met by a grant awarded to one of 
IIS by the Government Grant Committee of the Royal Society. 



** Preliminary Detenoination of the Wave-lengths of the Hydrogen 
Lines, derived from Photographs taken at Ovar at the 
Eclipse of the Sun, 1900, May 28." By F. W. Dyson, M.A., 
Sec. E.A.S. Communicated by W. H. M. Christie, C.B., 
M.A., F.E.S. Keceived January 17, — Read February 7, 1901. 

The spectrum of the "flash" obtained in observations of solar 
eclipses furnishes a method of determining the wave-lengths of the 
hydrogen series with great accuracy, as these lines are strongly shown 
and sharply defined. As the determination of these wave-lengths is 
somewhat removed from the general subject of eclipse spectroscopy, it 
seemed suitable for a separate paper. 

The following determination is made from four photographs taken 
near the beginning of totaHty at Ovar, at the eclipse of 1900, Ma^ 'i^, 

VOL. LXVIII. l> 



34 Mr. F. W. Dyson. 

in the expedition from the Royal Observatory, Greenwich. The spec- 
troscope used is a four-prism quartz spectroscope, kindly lent by 
Captain Hills. The length of the spectrum from h (X 4102) to the 
limit of the hydrogen series (X 3640) is 40 mm., so that the scale is 
about 10 tenth-metres to the millimetre. 

The spectra were measured with one of the astrographic micro- 
meters of the Royal Observatory (a micrometer originally designed for 
measuring the photographs taken at the transit of Venus) by com- 
parison with a glass scale divided to millimetres. The errors of the 
5-mm. divisions have been accurately determined in the course of 
investigations of the errors of the r^aux used in the photographic 
chart of the heavens. The errors of the intermediate divisions were 
determined by Mr. Da\id8on. The value of one revolution of the 
screw of the micrometer is approximately ^ mm. 

The wave-lengths were deduced from the measures by an interpola- 
tion formula, derived principally from the following lines, whose wave 
lengths are taken from Rowland's tables : — 

Ca 3968-625 Ti 3761464 

Ca 3933-825 Ti 3759447 

Ti 3913-609 CrTi ... 3757-824 

Ti 3900-681 Ti 3741-791 

Mg 3838-435 Ti Fe ... 3722729 

Mg 3832-450 Y 3710-431 

Mg 3829-501 Ti 3685-339 

Y 3788-839 FcTi ... 3659-901 

Y 3774-473 

These lines are the strongest lines in this part of the " flash " spec- 
trum. In some of the photographs a number of the strongest iron 
lines were also used as lines of reference. On the photographs taken a 
few seconds before the eclipse became total the iron lines are unsuit- 
able as lines of reference, as in some cases 1)oth a bright line and an 
absorption line are seen, and in other cases the lines have a grey 
appearance, and are not sharp and clear like the lines given above. 

The wave-length of h is only derived from one photograph, and is 
not determined accurately. The value obtained agrees with the result 
given by Mr. Wright,* in showing a correction of 0*1 of a tenth-metro 
to the value given by Rowland. 

The intensities of the lines are given somewhat roughly. With the 
exception of the cases noted where other lines apparently interfere, the 
diminution of intensity is sensibly uniform. 

A comparison has been made with the wave-lengths given by 

Balmcr's law, using the formula X = 3G46-140 ., . the constant of 

n^ - 4 

• * Astroph. Joiirn.,* vol. 9. 



IktermiiicUio)i of the Wave-lengtlis of the Hydrogen Lines. 35 

which agrees very closely with the wave-lengths of the three lines 
H«, H^, Hy given by Rowland. No correction to the formula has 
"been deduced, as only a small one is indicated, and it is flesirable to 
iise a larger number of lines of reference than has been employed in 
this investigation. The wave-lengths were determined from each series 
of measiures separately, and from the accordance of these the probable 
errors of the resulting determination of wave-lengths lie between 
± O'Ol and ± 0*02 of a tenth-metre for the different lines. 



, Hjdro. 




1 .^"^ 


Int. 


! line. 




£ 


i 40 


1 


'lO 


i 


00 


7 


;4o' 


« 


Iso 


t 


30 


1 K 


2b 


. A 


' IB 


f^ 


1 \% 


^ 


16 


1 


1« 


J 


1 15 


T 


13 


P 


11 


iT 


9 


1 - 


1 7 


1 


I C 


^ 


4 


i X 


i 


+ 


3 


m 


I 


fl' 


1 ^ 





1 4 


t 


1 


c* 


, » 


■ 
1 


1 



9 
10 
11 
12 
13 
14 
15 
16 
17 
18 

ly 

21 



23 

24 

26 

27 

28 
29 
80 
31 



Observed 
wave- 
length. 



Wave- i 

law. ; 



6 ; 4101 -88 

7 ' 8970-229 

8 3869 101 



3833-540 
3798 057 
3770 -763 
3750 322 
3731 565 
3; 22 060 
3712 109 
3703 981 
3697 -283 
3691 -670 
36S6 -950 
3682-954 
3(i79 -483 



22 3676 -568 



3678-914 ! 
3671-674 

3669-595 
3667 -891 
3666 185 
3.64-770 
3663 -565 
3G62 373 
3661 -475 



•907 + -03 



241 
216 

550 
-063 
'794 

315 
•531 

101 

133 
•015 

313 
•717 

992 
•967 

514 



; + 012 



1+010 

'+ -006 

i- 029 

-•007 

1- 034 

+ 041 

'+-024 

+ 034 

!+ -030 

1+ -047 

+ -0*2 

+ 013 

+ 038 

525 - 043 

920 + -006 



638 

625 
848 
256 
838 
553 
418 
3iO 



•06^1 



Bemarks. 



Onlj measured on one photo- 
graph. 

Helium line at 3888-785 not 
separated. 



Touching Fe line at 3735 -014. 



1+ 030 
-048 

; + 071 
+ ^068 

- -012 

+ -aw 

- -095 



f 3676-457 Fe Cr 1 probably 
1. 3676-698 Co J interfere. 

Probably Zr 3671 -412 inter- 
feres. 



Partly due to Y at 3664-760. 

Mainly due loTi at 3662 378. 
Possibly 6661 ^509 Fo inter- 
feres. 



36 Dr. H. H. Turner. On the 



'' On the Brightness of the Corona of January 22, 1898. Pre- 
liminary Note." By H. H. Turner, D.Sc., F.R.S., Saviliau 
Professor. Received January 18, — Read February 7, 1901. 

1. In a former note^ I gave some account of measures of brightness 
made on photographs of the corona of 1893 by Abney's method. The 
same method has been used on the coronal photographs taken in 1898 
and in 1900 (in 1896 none were obtained owing to cloud), and a large 
number of measures have been made, though the work is not yet 
complete. Pending the completion and publication of this work, it 
seems advisable to publish the present note, as one or two results 
have been arrived at which nuvy be useful to others in the forthcoming 
eclipse. 

2. As regards the method of measurement, sufficient has been said 
(for the present purpose) in the paper already quoted. It need only 
1>c added that in place of the revolving sectors a graduated wedge of 
gelatine was used to diminish the comparison beam, according to Sir W. 
A]>ney's more recent methods. The wedge or sectors are mere inter- 
mediaries between the coronal image and the standard squares, and no 
considerations beyond those of convenience are involved. The wedge 
is much more convenient, and the work can be done with it twice as 
rapidly. 

3. But a new method has been adopted of representing the results,, 
which, though an elementary change in some respects, has had the 
important consequence of suggesting a more satisfactory law for the 
variation of coronal brightness with distance from the sun. The only 
simple law (so far as I am aware) which has hitherto been formulated' 
was that proposed by Professor Harknoss in 1878, viz. : — 

Brightness a (distance from sun's limb) "2. 

Visual measures made by Thorpe and Abney in 1886 and 1893 could 
not be reconciled with this law ; though I showed in the paper already 
quoted that if the distance be measured from a point within the limit 
(about I radius within), the law approximately satisfied the photo- 
graphic measures. 

I have now been led to a completely new law, viz. : — 

Brightness a (distance from sun's centre)'^, 

which, though still on trial, is supported by a fair amount of evidence, 
and the suggestion arose in the following way : — 

4. The brightness curve in the previous paper was obtained by 
plotting brightness against distance. This gives a curve of hjrperbolie 

• ' Roj. Soc Proc.,' Tol. 66, p. 403. 



Brightness of the Coroim oj Jamuiry 22, 1898. 37 

ioi-m close to the two axes of reference, and difficult to compare the 
-observations with, for reasons which are tolerably obvious. The curve 
is still hyperbolic if log (brightness) be plotted against distance ; but 
if the brightness varies as any power of the distance, and we plot log 
^brightness) against log (distance), we get a straight line, which is 
particularly easy to compare observations with. The only difficulty is 
that we must know where to measure our distance from ; for if we add 
or subtract a constant to the distance, it will change the straight line 
into a curve. And unfortunately the point from which the distance 
was to be measured seemed just one of the things to be determined. 

5. But after some preliminary experiments I found that it was not 
<lifficult to find the proper origin from which to measure the distance, 
by the very condition that the curve was to be a straight line. 

Fig. 1. 




If in the equation 



log // + n log ./• = const. 



represented by the straight line AB in fig. 1, we write (x + a) for x^ 
then the calculated values of log y, when x is large compared with a, 
will be nearly the same as before ; but when ;>.' is small log (x + a) will 
be increased, and log y therefore diminished, and we get a curve such 
s& CD. (If a be negative, we get a curve such as EF.) And a very 
few trials (perhaps one alone suffices) give the value of a, which will 
straighten the curve. 

6. These values immediately pointed to the sun's centre as the 
proper origin for measurement; and when the observations were 
plotted on this assumption, the curve was practically a straight line, 
and the slope of this line indicated that the index n was 6, giving the 
law already stated, viz. : — 

Brightness oc (distance from sun's centre)"*^. 

7. But one further point is to be noted. The curve was practically 
straight for some distance from the limb, but then always \axy\\^^\ 



88 



Dr. H. H. Turner. On the 



upwards like the curve GH in fig. 2. Now comparing this vrith CD in 
fig. 1, it suggests that just as CD could be explained by tfie addition 
of a constant to the distance, which made a variable alteration in the 
log distance, so GH may l>e explained by the addition of a constant to- 



Fia. 2. 




the hrujhtMss, making a variable alteration in the log brightness. And 
there is a possible physical cause for this constant addition, Wz., the 
general sky illumination or glare which is added to the coronal bright- 
ness. A value of a1)out 0*012 of the average brightness of the full 
moon for this illiunination seems to satisfy requirements for the 1898 
photographs. 

8. I proceed to give a brief summary of the measures on the photo- 
graphs of 1898 so far as they have gone. 

Four photographs have been selected for measurement, three of 
them tiiken by me at Sahdol \nth exposures of 1 sec, 2 sees, and 20 sees., 
and one taken by Capt. Hills at Pulgaon with exposure 8 sees. On 
these, measures have been made along six radii extending approximately 
N., 8., E., W., N.E., and S.AV., the last two being as nearly as possible 
in the direction of the main streamer. 

9. The exposures given to the standard squares were all the same. 
These squares transmit fractions of the light ranging from to 4 on a 
scale of powers of 2, a range which might be extended with advantage, 
seeing that measures on the corona can be profitably made over a range 
of to 7 at least. But the smallness of the range is made up for in 
practice by the measurement of photographs with different exposures.. 
Thus the longer exposures of 20 sees, and 8 sees, in the above series 
control the fainter parts of the corona, and the shorter of 1 sec. and 
2 sees, control the brighter parts near the limb. 

10. In comparing the results from the different plates, it is found 
that the brightnesses shown by one plate differ from those shown by 
another in a constant ratio. Since the log (brightness) is tabulated 
this means a constant difference between similar numbers for the two 
plates. Following Sir W. Abney's pnictice, I have used the base 2 for 
the logarithms of brightness, and recorded to 0*1, which represents a 



Brightness of the Corona of Januwi-y 22, 1898. 39 

ratio of 2**^ = 1-07. (The logarithms of distance have been taken to 
base 10 in the ordinary way.) These differences between the plates may 
be due to any combination of the following causes : — 

(«.) Accidental error in exposure to corona. The exposures were 
made without any mechanism, and the short ones especially may be 
sensibly in error. Thus the difference between the 1 sec. and 20 sees, 
exposure is 0*8. If the whole of this be due to accidental error in the 
1 sec. exposure, it would mean that the exposure was for 1 sec. x 2~^** 
= 0*58 sec. instead of for 1*0 sec, which is not an extravagant suppo- 
sition. 

(6.) Accidental error in exposure to squares. This should be much 
smaller than (a.). 

(f.) Difference in sensitiveness of the film near the edge of the plate 
where the squares are impressed, and in the centre where the corona is 
impresssed. There is independent evidence of sensible differences of 
this kind, and the point is under investigation. 

(il^ Differences in the behaviour of the candle which impressed the 
squares on the various plates. 

(f*.) Climatic differences between Sahdol and Pulgaon. 

11. It becomes necessary to decide which plate to take as the 
standard. Cause (a.) ought not to affect the 8 sees, and 20 sees, appre- 
ciably, but cause (^.) may. They differ by 0*5, and we may perhaps 
take the mean. The corrections to be applied to the plates are then 

Plate I II III IV 

Exposure 1 sec. 2 sec. 8 sec. 20 sec. 

Place Sahdol Sahdol Pulgaon Sahdol 

Correction ... -hO-6 -0*2 -fO-3 -0*2 

If any other selection is preferred, it is easily applicable as a con- 
stant to the final numbers. 

12. The correction for constant illumination of the plate due to sky- 
glare has been adopted as 2~^ ** moon, taking the moon as equal to 0*02 
of a candle at 1 foot. If at any point the corona has a brightness 
represented by a;, meaning 2* x moon, then the brightness measured on 
the plate will appear as y where 

2^^ 4- 2~*^"* = 2". 

A table was formed giving // in terms of a;, of which the following is 
a portion : — 



40 



D)-. H. H. Turner. (Jn tlu 





Correction 




X, 


to J. 


*• 


2-0 


00 


-20 


30 


+ 01 


-2-9 


40 


+ 0-2 


-3 -'8 


5-0 


+ 0-4 


-4-6 


60 


+ 0-8 


-5-2 


70 


+ 1-3 


-5-7 


8-0 


+ 2-0 


-60 



13. The measures on the plates were then corrected — 

(rt.) For the particular plat«, as in § 10 ; 
(p.) For the sky-glare, as in § 11 ; 

and compared with the curve 

l)nghtnos8 x (distance)' = A 

to get the vahie of the constiint A for each of the six nulii measured. 
As above explained, the curve used was a straight line, obtained by 
plotting log brightness as ordinate and log distance as abscissa. The 
constants found for the six nwlii were as follows — adopting as unit of 
brightness that of the moon (assumed 0*02 candle at 1 foot), and of 
distance that of the sun's radius, so that the constants represent the 
brightness of the corona at the sim's limb expressed in moons : — 



Badius. N. 


N.E. 


K. 


s. 


s.w. 


W. 


Mean. 


A = +0-4 


+ 1-9 


+ 1-7 


00 


+ 2-3 


+ 0-6 


+ M5 



Thus at the sun's limb the corona is more than twice as bright as the 
full moon on the average. 

14. Finally, the individual measiu-es were compared \vith the adopted 
law, with the following results. In the column " Typical Curve " the 
calculated brightness is given for A = + 0*6, the actual figures for the 
different streamers differing from this throughout by constants which 
are easily inferred from the values of A given iilK)ve. 



Bt^Jvtness of the dyi'ona ofJanvxinj 22, 1898. 



41 



Table I. — Comparison of Observed Brightness (Photogr.aphic) of 1898 
Corona with the Law. 

Brightness x (distance from Sun's centre)^ = constant. 

•{The distances were measured in divisions of 13 to the Sun's radius. 
The brightnesses are expressed by powers of 2, zero representing 
Moon's brightness.) 



Distance 

from 
Sun's 


Typical 
brightness 
of corona 

alone. 


brightness 
1 with 


ObsezYod error of formula. 


1 centre 
, in radii. 


"glare" 
added. 


Plate. 


N. 


N.E. 


K. S. 


S.W. W. 


1-08 


^ 1 


' +01 


I 


+ 0-6 




-0 1 +0-7 


— +0-4 


115 


- 0-4 


-0-4 


I 


+ 0-6 


-0-1 


0-0 +0-4 


-0-7 +0-4 


1-23 


- 1-0 


-10 


I 


+ 0-2 


— 


-01 +0-2 


-0-4 


1-31 


- 1-5 


-1-5 


I 


+ 0-5 


+ 0-1 


+ 0-2 1-0-2 


-0-3 ! + oi 


1 -88 


- 2-0 


-.2-0 


I 


-0-4 





0-0 I 0-0 


0-0 t +0 1 


1 -46 


- 2-5 


-2-4 


I 


0-0 


+ 0-1 


-0 5 +0-3 


-0 1 1-0 1 


1-61 


- 8-3 


-3 1 


I 


-0-3 


-0-5 


-0-7 — 


0-0 i — 


1-77 


- 4-1 


-8-8 


I 


— 


-01 


— — 


+ 0-2 — 


1-92 


- 4-9 


-4-4 


I 


— 


-0-1 — — 


+ 0-2 


— 


. 1-31 


- 1-5 


-1-5 


II 


+ 0-3 


— — -01 


__ 


._ 


1-88 


- 2 


-2 


II 





— , — -0-3 


— +0-2 


1*46 


- 2-6 


-2-4 


II 


-0-2 


— — '-0'5 


— -0 1 


1-54 


- 2-9 


-2 8 


II 


-0-3 


+ 0-5 +0-6 -0-3 


— -0-2 


1-61 


- 3-3 


-3 1 


II 


-0-4 


+ 01 +0-2 -0-3 


+ 0-3 -0-2 


1-77 


- 4-1 


-3-8 


II 


-0-2 


-0-2 1+01 -01 


-01 -01 


1-92 


- 4-9 


-4-4 


II 




-U-2 i+01 


.» 


+ 0-1 — 


2 15 


- 5-8 


-5 1 


II 


+ 01 


-0-3 +0-1 


— 


+ 0-2 — 


2-54 


- 72 


-5-8 


II 




— — 


— 


+ 0-3 — 

1 


1-46 


- 2-5 


-2-4 


III 





._ [ 


+ 01 


1 


1-61 


- 3-3 


-3-1 


III 





— ' — 


+ 1 


— 


1-77 


- 41 


-3-8 


III 


+ 01 


+ 0-4 , + 2 


+ 0-1 


00 -01 


1-92 


- 4-9 


-4-4 


III 


-01 


+ 0-2 +0-2 


+ 0-1 


-hOI 


-0-2 i 


2-15 


- 5-8 


-5 1 


III 


-0 1 


-0 1 


+ 01 


0-0 


00 ' 


2-54 


- 7-2 


-6-8 


III 


+ 0-2 


+ 0-2 +0 1 


— 








2-92 

1 


- 8-5 


-6 1 


III 


— 


+ 0-4 0-0 




-0 1 


— 


1-92 


- 4-9 


-4-4 


IV 


+ 01 


_ __ 


+ 0-3 


_ 


_ 


2-08 


- 5-5 


-4-9 


IV 


+ 0-2 


-0-4 ' — 


+ 4 





+ 0-4 


2-23 


- 6-1 


-5-3 


IV 


+ 0-2 


-0 2' 


+ 0-4 


— 


+ 0-2 


2-38 


- 6-7 


-5-6 


IV 


— 


-0.2 :+o-i 







+ 0-2 


2-64 


- 7-2 


-5-8 


IV 


+ 0-2 


-0 -2 -0 


+ 0-5 





+ 2 


2-92 


- 8-5 


-6 1 


IV 


-01 


-0-2 +0 1 


+ 0-3 





+ 0-3 


8-31 


- 9-6 


-6-3 


IV 


— 


-01 +0 1 


+ 1 


-0 1 





8-69 


-10-5 


-6 -3 


IV 


— 


-0-2 00 — 


-0-3 


— 


4-08 


-11-4 


-6-4 


IV 


— 


-0-4 - , - 


-0-3 


— 



15. Considering the irregularity of the coronal structure, we cannot 
perhaps expect better agreement with any simple law of brightness 
than is G^wn by these residuals ; and the assiuned law, whether it l\a% 



42 



Dr. H. H. Turner. On the 



any physical significance or not, is, at any rate, a convenient method of 
expressing the facts. We may now turn to the measures previously 
given of the 1893 corona,* and see how they accord with this formula. 
On trial, it is found that a fair accordance can be seciu'ed if the con- 
stant correction for sky-glare be taken as 2"'^^ instead of 2"®'*, and the 
constants for the four radii measured be 



N. 


s. 


E. 


W. 


Mean. 


01 


+ 0-4 


+ 0-5 


+ 01 


+ 0-23 



16. With regard to the smaller value for sky-glare, if this depends 
on the general brightness of the corona itself, we may remark that the 
1893 corona was generally fainter, according to the measures, than the 
1898 corona, the mean constant for the former being 4- 0*23, and for 
the latter + M5. The difference is + 092, so that the 1898 corona 
was about twice as bright, and hence twice as bright a sky illumination 
is not unreasonable. 



Table II. — Comparison of Observed Brightness (Photographic) of 
1893 Corona with the Law. 

Brightness x (distance from Sun's centre)^ = constant. 

(The distances are given in units of the Sun's radius. The bright- 
nesses are expressed by powers of 2 ; zero representing the Moon's 
brightness.) 



Distance | Typical 



Sun'8 
centre. 



1 
2 
3 
4 
5 
6 
7 
'8 
9 
•0 
1 
2 
2-3 
2-4 
2-5 
2-6 

2 7 
2-8 
2-9 

3 



of corona 
alone. 



+ 0-2 
-0-6 
-1-2 
-1-9 
-2-5 
-3 
-3-6 
-4 1 
-4-6 
-5-0 
-5-4 
-5-8 
-6-2 
-6-6 
-7 
-7-3 
-7-6 
-7*9 
-8-2 
-8-5 



With 
'glare" 
added. 



+ 0-2 
-0-6 
-1 -2 
-1-9 
-2-5 
-2-9 
-3-5 
-4 
-4-4 
-4-8 
-6-2 
-5-5 
-5-8 
-6 1 
-6-3 
-6-5 
-6-7 
-6-8 
-7-0 
-7-1 



-0 1 

+ 0-4 
+ 0-2 


-0 1 

0- 
-0- 
-0- 
-0- 
-0- 
-0-3 
+ 0-2 
+ 1 
+ 0-3 

+ 0-3 

+ 0-3 



bserved error of formula. 


S. 


1 

E. 


w. 


-0-9 


_ 


_ 


-0-4 


r-> 


— 


-0-1 


— 


+ 0-1 


4 0-4 


-0-3 


+ 0-3 


+ 0-4 


— 


+ 0-6 


+ 0-3 


— 


— 


+ 0-4 


— 


+ 0-3 


+ 0-2 


+ 0-5 


+ 0-1 


+ 01 





0-0 


-0 1 


— 


— 


-0-2 


— 


-0-3 


-0-2 


-0-2 


-0-7 


-0-3 


— 


0-0 


-01 


— 


— 





— 





00 


0-0 


+ 01 


+ 0-1 


— 


-0 1 


-0 1 


— 


— 


-0 1 


— 


+ 1 


-01 


00 


+ 01 



.-J 



' Eoy. Soc. Proc.,' vol. 66, p. 403. 



Brightness of the Coronn 6f January 22, 1898. 43 

17. The discrepancies are again not large, and some of them may be 
due to the extrapolation which was necessary for the brighter parts of 
the corona, the standard squares not having been given a long-enough 
exposure (as stated in the former paper) to compaie with the long 
exposure of 50 sees, to the corona. Measures on plates with a shorter 
exposure to the corona will perhaps allow of more accurate results near 
the sun's limb. Unfortimately no plate is available with an exposure 
shorter than 5 sees., but measures on this plate, so far as they have 
gone, indicate a closer accordance with the theoretical formula near the 
limb. Further measures are, however, required. 

18. With the assumed law 

brightness = Ar"^\ 

where r represents distance from the sun's limb in solar radii, the total 
brightness of the corona is 

the total brightness of the full moon being represented by 

I 2Trrdr = t. 
Jo 
Thus the ratio of the total brightness to that of the moon is i A, 
In 1898 the value of A was approximately 2^^^ = 2*2, and thus the 
whole corona was about equal to the full moon. In 1893 the value of 
A was 2^23 =1-2; and the whole corona was thus about 0*6 of the 
full moon. 

19. But we have omitted the constant illumination of the sky in this 
integral. If we include a portion of sky extending to distance E from 
the limb, and B be the value of the constant for "glare," which in 
1893 was taken as 2"' ^ = 0*0046, and in 1898 was 2"*^^ = 0-012, then 
we must add to the above quantities 

lBp27rn//- = B(R-^ - 1) full moon. 

It is not, however, easy to assign a definite value to K. 

20. The integral brightness of the corona was measured in 1893 by 
the late Mr. James Forbes, jiui.,* and found to be 1*1 full moon. We 
find [0-6 + B (R2 - 1)] full moon. 

If the two quantities be equated, we get 

B(R-' - 1) = 0-5 
or K2 = 0-5/0 0046 

= 110 
or R - 10-5. 

• * Phil. Trans./ A, 18l»6, p. 433. 



44 Prof. J. Dewar. The Boiling Point of Liquid Hydrogen, 

Thiis, if we suppose that Mr. ForlMJS measured the total light within 
a circular area 5"* in diameter, which seems a fair supposition,* the 
two measures of total brightness agree. 

On the same supposition, the value of B (R- - 1) in 1898 would be 
1*3 full moon, and the total brightness of the corona woidd appear as 
M + 1-3 = 2-4 full moon. 

Sumimry, 

(a,) The brightness of the corona of 1898 at a point distant r from 
the sun's cmtre expressed in solar radii may be approximately repre- 
sented by the formula 

brightness = A/~'^ + B, 

where A and B are constants. 

{!),) The first term may be considered as corona proper, while B may 
be taken as representing the constant illumination of the sky, or glare. 
In 1898 the value of B was 2"'''* = 0-012 moon, tiiking the brightness 
of the moon as 0*02 candle at 1 foot. 

(r.) The constant A varies with the radius along which measures are 
made. In 1898 it varied from 2^ '• moon to 2^ ^ moon, the mean being 
2'^^* moon or 2*2 moon. 

((/.) The same formula will fairly represent the 1893 corona, the 
mean value of A being 2^'^ = 1-2, and the value of B 2-""» = 0-0046. 

(^.) The total brightness of the corona depends on the area of sky 
included. If a circular area 5' in diameter be included, the total 
brightness of the 1893 corona may be taken as 1*1 full moon, agreeing 
with the visual measures made, and that of 1898, on the same supposi- 
tion, would be alx)ut 2*4 full moon. 



" The Boiling Point of Liquid Hydrogen, determined l»y Hydrogen 
and Helium Gas Thermometers." By James Dewak, M.A., 
LL.1)., F.K.S., Professor of Chemistry at tlie Royal Institution, 
and Jacksonian Professor, University of Cambridge. Re- 
ceived Januar}' 8, — Read February 7, 1901. 

In a former papert it was shown that a platinum-resistance thermo- 
meter gave for the boiling point of hydrogen - 238^*4 C, or 34''6 

• Tlie dinieusions of the box are not given, either here or in the proTious paper 
to whicli we are referred ; but on p. 369 of the ' Philosophical Transactioiu, 
A, 1889, there is a diaf^ram of the box, from which it would appear that the angular 
aperture wiu not greater than 12^, judging bj outside measurements. 

t " On the Boiling Point of Liquid Hydrogen under R(Kluoed Pressure," * Roy. 
Boo. Proc./ 1898 (vol. 64, p. 227). 



determined by Hydrogen and Helium Gas Thennometei'S. 45 

absolute. As this value depended on an empirical law correlating 
temperature and resistance, which might break down at suoh an excep- 
tional temperature, and was in any case deduced by a large extrapola- 
tion, it became necessary to have recourse to the gas thermometer. 

In the present investigation the advantage claimed for the constant 
pressure gas thennometer over the constant volume thermometer is 
absent. The effect of high temperature combined with large increase 
of pressure does not occur in these experiments, where only very low 
temperatures and a maximum range of pressure of less than one atmo- 
sphere were encountered. At the same time, before dispensing with the 
effect of pressure upon the capacity of the reservoir of the thermometer, 
it was carefully estimated and found that it could not affect the volume 
of the reservoir by as much as 1 /60,000th part. This being determined, 
a particular advantage results from the use of the constant volume 
form, because in its case it is unnecessary to know the actual volumes of 
the reservoir, and of the " outside " space. It is only necessary to know 
the ratio of these two volumes, and as this ratio appears only in the 
small terms of the calculation, it is not a serious factor in the estimation 
of such low temperatures. 

Two constant volume thermometers (called No. I and No. II) were 
employed, in each of which the volume of the reservoir was about 
40 c.c, and the ratjio of the outside space to the voliune of the reservoir 
was 1/50 and 1/115 respectively. A figure of the apparatus is given 
herewith, where A is the thermometric bulb covered with a vacuum 
vessel to hold the liquid hydrogen, and be exhausted when necessary ; 
B is the manometric arrangement for adjusting the mercury at C to 
constant vohune, and D is the barometer. The readings were made 
on a fixed scale by means of a telescope with cross-wires and level 
attached. A similar telescope was permanently fixed on the mark to 
which the volume had to be adjusted. As the observations had to bo 
made quickly, it was foimd convenient to use both telescopes on the 
same massive stand and to read the barometer placed alongside 
simultaneously. 

The formula of reduction used was that given by Chappuis in the 
* Travaux et M^moires du Bureau International des Poids et Mesiu-es/ 
tom. vi. p. 53, namely, 

where Vo is volume of reservoir at 0* C, 

T, temperature of reservoir, measured from 0° C, 

t», volume of " outside " space at the temperature of the room, 

^, temperature of the room, 

a, coefficient of expansion of the thermometric gas, 



46 Prof. J. Dewar. The Boiling Paint of Liquid Bydrogen, 

EXHAUST 



hAiE^V^ 




P, coefficient of alteration of volume of reservoir, due to chaiigi 
pressure, 

8, coefficient of expansion of substance of reservoir, 

Ho, initial pressure (in tliese experiments always refluccd to 0* C. 



detej'^mined by Hydrogen atui Helium Gas Thtrmmneta^s. 47 

Ho + A, pressure at temperature T, after all corrections have been 
made. 

On putting /J = as already explained, equation (1), by algebraic 
-transformation and without any approximation, was altered into the 
form 

^ rr 273 -h / + 0-273 .^. ^ ^ /.n 

^==^^273Trr-rTr'^'^^^ = ^^^' ^^^' 

-^-^ '^-Jr^ (^)' 

V 

in which Po and P replace Ho and Ho + h, and x = __ - 

Vo(l + at) 

The gases used as thermometric substances were hydrogen, oxygen, 

helium, and carbonic acid. The values of a adopted in equation (3) 

were taken from Chappuis' memoir, and were 0*00366254 for the first 

three, and 0*00371634 for carbonic acid. The reciprocals of these 

coefficients are 273*035 and 269083. The munber "273" which 

appears in ^ is so nearly equal to the reciprocal of the former value 

for a, that it was allowed to remain for the first three gases ; but in 

dealing with carbonic acid it was replaced by 269*083. 

In these experiments Ti is always negative, and numerically less than 

273, so that the value of ^ is always greater than unity ; nevertheless 

it differs from it but slightly, its value being unity when Ti = - 273" C, 

And rising to 1*02 when Ti = 0** C. in the case of thermometer No. I, 

where x = 1/50. It may be noted that when 8 is neglected Ti is the 

usual value given by Boyle's law ; there is a convenience, therefore, in 

this form of Chappuis' formula for approximation, because Ti can 

•quickly be calculated, and the correcting factor 6 can be applied later 

if desired. 

In the first experiment (No. 1 of subjoined Table I) thermometer 

No. I was filled vrith electrolytic hydrogen. The initial pressure (the 

pressure at 0** C.) was almost three-eighths of an atmosphere, and was 

taken low in order to obviate any complication from condensation on 

the walls of the reservoir. Two other possible causes might abnormally 

reduce the pressure at very low temperatures ; these were polymerisii- 

tion and the presence as impurity of small quantities of gases liquefying 

above the boiling point of hydrogen. The measurement of the density 

of the gas at its boiling point showed that there was no polymerisation, 

and further proof of this was evident in the constancy of the value of 

the boiling point when different initial pressures were taken. To guard 

against the presence of gases vrith a higher boiling point than hydrogen, 

the electrolytic hydrogen was allowed to pass continuously for eighteen 

hours through the thqrmometric bulb before it was sealed off. It was 

fiuther calculated that an impurity of oxygen necessary to reduce the 

boiling point of hydrogen by a degree would amount to ^ pet e^wX., \\. 



48 Prof. J. Dewar. The Boiliiu) Point of Liquid Hydrogin, 

quantity too largo to escape detection. This experiment gave the 
boiling point of oxygen as - 182*'*2, and that of hydrogen as 
- 253'^0. 

In the second experiment (No. 2) a new thermometer, No. II, was 
constructed with a much smaller value of a*, and as a further protection 
against the presence of impurities, palladium hydrogen was employed as 
the source of the gas. A rod of palladium, weighing about 120 
grammes, kindly placed at my disposal by Mr. George Matthey, 
F.R.S., was charged with hydrogen in the manner described in my 
paper " On the Absorption of Hydrogen by Palladium at High Tem- 
peratures and Pressures,"* and subsequently used as the source of 
supply to fill the thermometer. The initial pressure was slightly lesp 
than that in the first experiment; the corresponding results were 
-182^-67 and -253''-37.t 

The new thermometer was filled afresh (No. 4) with palladium 
hydrogen at an initial pressure rather less than one atmosphere, and 
gave for the boiling point of hydrogen the temperature — 252*-8. 
This result is a confirmation of the absence of polymerisation. 

The next step was to compare these results with the results of 
similar experiments made upon another gas whose boiling point fell 
within the range of easily determined temperatures ; and as a further 
precaution the gas used in the thermometer was the vapour rising from 
the liquefied gas whose boiling point was to be determined. The gas 
first selected was oxygen (No. 5), and as an additional condition to be 
noted, the initial prcssiu'c was made slightly more than an atmosphere, 
so that it would be in a Xaw der WaaFs " corresponding " state with the 
hydrogen in the first two experiments, namely, the initial pressure in 
each case was about 1/50 of the critical pressure. The critical pressure 
of oxygen was taken about 51 atmospheres, and that of the hydrogen 
about 18 atmospheres. There are good reasons for believing that the 
critical pressure of hydrogen is more likely to be about 11 or 12 atmo- 
spheres. In the event of the lower value being eventually found the more 
correct, the eflect as l)etween the oxygen thermometer and the hydrogen 
thermometer will l)e to make the boiling point of hydrogen a little too 
high. The result obtained from this experiment was to place the boiling 
point of oxygen at - 182°'29, thus corroborating in a satisfactory 
manner the reliability of the method of detemiiniug the boiling point 
of hydrogen. 

The question still remained, How far is a gas thermometer to be 
trusted at temperatures in the neighbourhood of the boiling point of 
the gas with which it is filled ? To answer this question the oxygen 
thermometer was used to determine the boiling point of liquid air 
(No. 7) in which a gold-resistance thermometer was simultaneously 

• * Proc. Cliom. Sop.,' 1897. 

t This tlieniiomctiT gave 99°-7 for the boj^ng point of water. 



determined by Hydrogen and Heliuvi Gas Thermometers. 49 

immersed. The gold thermometer had been previously tested and 
found to give correct indications of temperature down to temperatures 
not only well below the point in question, but lower than those obtain- 
able by any other metal thermometer. In the result the oxygen ther- 
mometer gave - 189***62, and the gold thermometer - 1 89^-68, as the 
temperatiu'e of that particular sample of air boiling at atmospheric 
pressure. 

For another method of comparison this oxygen thermometer was 
partially discharged (No. 8) until its initial pressure was nearly the 
same as that in the first hydrogen thermometers. In this state it gave 
the boiling point of oxygen as - 182* '95, establishing again the reli- 
ability of the method. All the boiling points of the liquid gases were 
made on samples produced at different times. 

As an extreme test of the method, I charged the thermometer No. II 
with carbonic acid (No. 11) at an initial pressure again a little less than 
one atmosphere, and used it to determine the boiling point of dry CO2 ; 
the result was - 78*'*22, which ia the correct value. 

Hence it appears that either a simple or a compound gas at an initial 
pressure somewhat less than one atmosphere, may be relied on to deter- 
mine temperatures down to its own boiling point, in the constant 
volume gas thermometer. 

Another thermometric substance at our disposal, as suitable for 
determining the boiling point of hydrogen as hydrogen had been in 
determining that of oxygen and other gases, is helium. The early 
experiments of Olszewski and my own later ones showed that pure 
helium is less condensible than hydrogen, and that the production of 
liquid or solid products by cooling Bath heliimi to the temperatures of 
boiling and solid hydrogen was only partial, and resulted from the 
presence of other gases undefined at the time the experiments were 
made. The mode of separating the helium from the gases given oft* by 
the King's Well at Bath is fully described in my paper on " The Lique- 
faction of Air and the Detection of Impurities."* 

If the neon, present as impimty in the Bath helium which was used, 
should reach its saturation pressure about the boiling point of hydro- 
gen, the values given by this thermometer for the boiling point of 
hydrogen would be too low. In order to avoid this, the crude helium 
extracted from the Bath gas was passed through aU-tube cooled by liquid 
hydrogen to condense out the known impiu-ities —oxygen, nitrogen, and 
argon. In my paper " On the Application of Liquid Hydrogen to the 
production of High Vacua,"t it was shown that at the temperature of 
boiling hydrogen, oxygen, nitrogen and argon have no measurable ten- 
sion of vapour, and that the only known gases uncondensed in air after 
such cooling were hydrogen, helium, and neon. This same neon material 

• 'Chem. Soc. Proo.,' 1897. 
t 'Toy. Soc. Proc./ 1898 (vol. 64, p. 231). 
VOL. LXVm. IS. 



50 Prof. J. Dewar. TJte Boiling Point of Liquid Hydrogen, 

occurs in the gas derived from the Bath wells. A sample of helium 
prepared as above described, which had been passed over red-hot 
oxide of copper to remove any hydrogen, was found by Lord Rayleigh 
to have a refractivity of 0*132. The refractivity of Eamsay's pure 
helium being 0*1238, and that of neon 0*2345, it results that my 
helium contained some 7*4 per cent, of neon, according to the refrac- 
tivity measurements. This would make the partial tension of the 
neon in the helium thermometer cooled in the liquid hydrogen to be 
about 4 mm., and this being taken as the saturation pressure the boil- 
ing point of neon is about 34** absolute. The initial pressure (No. 9) 
was taken rather less than a^ atmosphere, and the temperature of the 
boiling point of hydrogen was given by this thermometer as - 252' *68. 
A further observation (No. 10) was taken on another occasion with the 
same thermometer, and the value found was - 252''*84. The fact that 
the boiling point of hydrogen, as determined by the helium thermo- 
meter, is in substantial agreement with the results obtained by the use 
of hydrogen itself is a conclusive proof that no partial condensation 
of the neon had occurred. 

Of the remaining experiments in Table I, (No. 3) was made in order 
to show the effect of a very small initial pressure, one-sixth of an 
atmosphere. The results were unsatisfactory, owing to the sticking of 
the long column of mercury giving uncertain pressure readings. In 
this case an error in the reading of a low pressure has six times as 
great an effect as if the initial pressure had been about an atmosphere. 
If the temperatiure deduced for the boiling point of oxygen is corrected, 
and the same factor of correction applied to the observed liquid hydro- 
gen boiling point, then it becomes - 251 "•4. 

It is of particular moment to have some estimate of how far errors 
in the observed quantities employed in Chappuis' formula affect the 
final value of T. 

In the case of an error in ^, on differentiating equation (2) we get 

,rp rp - ir(273 -l-Ti) ,, ,,. 

^^ = ^^ (273 V ^ - ^t.r^ (^>- 

li x^ 1/50, < = 13% Ti = - 180%* then dT = 0*00339t//, or it would 
need an alteration of 2^ in / to alter T by 1/lOOth of a degree at the 
boiling point of oxygen. In the same circumstances when Ti = - 250, 
</T = 0*00136 dt, so that an alteration of between V and 8** in the 
value of t would only affect the boiling point of hydrogen by 1/1 00th of 
a degree. 

From equation (4) the error in T varies with x very nearly. Thus 
for the second thermometer where a^ = 1/115, a variation of / to the 
extent of 6% would only affect the boiling point of oxygen by 1/ 100th 

^of a degree; and it would require an alteration of 17Mn / to affect 

"*»e boiling point of hydrogen to the same extent. 



deto'mliied hy Hydrogen and Helium Gas Thermometers. 



-^ OH 

^_ 

I 

•^ 6 H 



O H 



i^ 



i^ 



ii 



o 

I 



i* 



O 



O 



.2^ 






9o • 9 



Is I 









M 

o 



H 

o 



is 

OS ^ 



B i 



t :§, 



(ii&j 



S^ so • I g « 



99 c® 



I I I 






%H Eoi 



B'-» c N 05 '^ I •-• 



i^ 



S c 

II 



;! 



g 

2 H 



1.2 r 



3 



oD<o M t> y 






^^ y ec o »p 



^ I 



09 

I 



"I 
I 



1^ I I I 



I 1 



^ 



I I I 



I I 



6) wd 

3^ O 



gsi| 

M 7 



U5 l-* t«» 

fH ©I 

I I I 



I I 



lb 
I 



01 

I 



0.2 



b 



z 



II a 



s. 



&l 



5° 



* O -< w w ^ 



5 :2 

g. -2 a 
5 eg. 



= ^a ^ 









o »« 


u 


•r 


5" 


<J 


o 


« 


u 


c 


^ 


s, 




u 


i 


6 


« 


t 


n 


A 


O 


60* 









o^ 

CO ^ 

© g 



o 



52 Prof. J. Dewar. The BoUing Point of Liquid Hydrogen, 
In the case of an error in P, a similar process gives 

(aPo - 6P)2 273 + / - xTi ^ ^ 

If X = 1/50, t = 13% Po = 760 mm., Tj = - 180'; rTT = 0-3563 (fP. 
so that an error of 1 mm. in P would only alter the boiling point of 
oxygen by a third of a degree. In the same circumstances at - 250% 
^rr = 0*3516 r/P, which is practically the same result at the boiling point 
of hydrogen as at that of oxygen. 
For the second thermometer, these two equations become 

at - 180% rfT = 0-3575 ^P, 
at - 250% f/T = 0-3548 (/P. 

In each of the last four results if Po = - x 760 mm. the formula 

n 

become respectively 

(fr = ?i X 0-3563 (l?, and ^/T = 7t x 0*3516 c?P, 
(/T = 7?. X 0*3575 rZP, and (ZT = ?i x 0*3548 (/P ; 

in other words, any error in reading P is magnified in its effect on T 
directly in proportion as Po is diminished. This affords some expla- 
nation of the weakness of the results in Experiment (No. 3). 
In like manner, from an error in Po, we get 

'^=-?J''^« («^ 

Here if x = 1/50, t = 13% Po = 760 ram., Ti = - 180=* ; 
ill: = - 0*1188 (ZPo, 

or an error of 1 mm. in Po would only alter the boiling point of oxygen by 
ji ninth of a degree ; but with the same data at - 250% ^ = - 0*0264(flPo, 
so that the boiling point of hydrogen would only be altered by a tenth 
of a degree for a change of 4 mm. on an initial pressiu^ of about one 
atmosphere. 

In this case also if P,j = - x 760 mm. we get similar results to those 
n 

in the case of P, namely, 

For X = 1/50, (IT = - n x 0*1188 ^^P^, and r/T = - n x 0-0264rfP^ 
For X = 1/115, (IT = - 71 X 0*1 192 (/Po and dT ^ -n x 0-0266 (ff». 

The general result of an error in either Po or P is, that the more 
reliable experiments are those in which the initial pressure ia as high 



determine hy Hydrogen and Helium Gas Thermomders, 53 

as possible. Hence Nos. 4, 9, 10 are in this respect the most reliable 
for hydrogen. Also, it is of much more importance that P should be 
accurate than that Pq should l)e so ; in fact, for hydrogen an error in P 
has 14 times as much effect as the same error in Pq. 

We can verify these results from Table I. In Experiment (No. 2), 
where Po = J x 760 nearly, we have two readings — one at the boiling 
point, the other in solid hydrogen, — namely, 19*7 mm. and 14-4 mm., 
whose difference is 5*3 mm. This corresponds to c/T = 3xO*3516(-5-3) 
degrees, or 5' -59. The calculated temperatures for these pressures 
are -253" 37 and -258"-66, whose difference is 5*29, a satisfactory 
agreement. 

If we compare Experiments Nos. 4 and 9, in both of which the same 
value of a is used, we can pass from the former to the latter by the 
formula 

(fr = - 00266 c/Po + 0-3548 ^/P, 

in which dPo = ~ 11 mm. and e/P = -0*5 mm., whence (IT = 0''152 
the observed result is -252"-683 + 252"-806 or 0'-123, which is also 
satisfactory and explains how so great a drop as 11 mm. in Po has, 
nevertheless, so slight an effect on the result. 

An alteration in the value of x has but little relative effect on the 
results. As before we have 

^ _ ^ (273 -h 0(273 + T,) ^ .. 

lix = 1/50, / = 13, then 

at Ti = - 180% (IT - - 57 085 die, 
atTi = - 250', (Hi = - 19-4205 (fo, 

and for the second thermometer {x = 1/115) in like circumstances, 

and (ZT = - 57-895 dx. 

rfT = - 19-802 (/a 

For insUuice, if x were altered from 1/SO to 1/80 the result would be 
to raise the boiling point of oxygen by 0'-43 and that of hydrogen by 
0*'15. 

Finally, the alteration of a for any particular gas, being in any case 
small, affects the value of T practically only in its main factor T]. To 
hundredths of a degree therefore the change in T is inversely pro- 
portional to the change in a, or, in other words, is directly proportional 
to the corresponding absolute zero. 

For instance, in Experiment (No. 11) had we used the siime value of 
fit as for hydrogen the boiling point of dry COj would have been 
- 79^-35. 



54 



The Boilin/f Point of Liquid Bydrogen, 



The following table shows what alterations would be required 
each of the thermometers, in the values of f, P, Pq, and x to alter 
boiling point of oxygen or that of hydrogen by 1/10 or 1/100 • 
degree. The table is calculated f or ^ = 13" ; and in the cases of P 
Po the initial pressure is taken to be alK>ut 1/wth of an atmosphere. 



Table II. 





Tliermometer 
No. 1. 


Thennometer 
No. 2. 


Alteratio 
of T. 


.fatB.P.ofO .. 
natB.P.of H .. 


2F 
7i° 


6*^ 
17° 


1 ^ 
100 


rat B.P. of . . 
Lat B.P. of H . . 


0-280^^ 

mm. 

n 

mm. 


0-280__ 

mm. 

n 

0-282 


1° 
10 


n 




ratB.P.ofO .. 
LatB.P. of H .. 


0-842 
— — mm. 
n 

3V9__ 

mm. 

n 


0*839^^ 
n 

mm. 

n 


1' 
10 


fat B.P. of .. 
* lat B.P. of H .. 


0*88 per cent. 
2-57 „ 


2 -00 per cent. 
5-81 „ 


1 *» 
100 



Thus, for example, if the iriitial pressiu-e in either thermometer \ 
about half an atmosphere an error of 1/7 mm. in reading P would a 
T by a tenth of a degree. 

If we take the average values given by these experiments as \n 
the most probable, then the boiling point of oxygeft is - 182^*5 
that of hydrogen is - 252 ''5, or 20-5 absolute. The tempera! 
found for the l)oiling point of oxygen agrees with the mean result 
Wroblewski, Olszewski, and others. If the boiling point of oxyge 
raised to - 182% which is the highest value it can have; then.an e< 
addition to the hydrogen value must follow, making it then - i 
or 2r absolute. In a futiu-e communic^ition the temperature of s 
hydrogen will l)e discussed. 

I am indebted to Mr. J. D. H. Dickson, M.A., of St. Peter*s Coll 
Cambridge, for help in the theoretical discussion of the results, am 
Mr. Robert Lennox, F.C.S., for able assistiince in the conduct of 
experiments. 



On the Influence of Ozone on the Vitality of somt BacterUi. 55 



February 14, 1901. 

A. B. KEMPE, M.A., Treasurer and Vice-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. ''Some Additional Notes on the Orientation of Greek Temples, 
being the Result of a Journey to Greece and Sicily, in April 
and May, 1900." By F. C. Penrose, F.RS. 

II. " The Transmission of the Trypamsoma Evansi by Horse Flies, and 
other Experiments pointing to the Probable Identity of Surra 
of India and Nagana or Tsetse-fly Disease of Africa." By Dr. 
Leonard Eogers. Communicated by Major D. Bruce, 
R.A.M.O., F.R.S. 

III. " On the Influence of Ozone on the Vitality of some Pathogenic 

and other Bacteria." By Dr. A. Ransome, F.R.S., and 

A. 6. R. FOULERTON. 

IV. " On the Functions of the Bile as a Solvent." By B. Moore and 

W. H. Parker. Communicated by Professor Schafer, F.R.S. 

V. " On the Application of the Kinetic Theory of Gases to the 
Electric Magnetic, and Optical Properties of Diatomic Gases." 
By G. W. Walker. Communicated by Professor Rucker, 
Sec. R.S. 

VI. ** Heredity, Differentiation, and other Conceptions of Biology : 
A Consideration of Professor Karl Pearson^s Paper *0n the 
Principle of Homotyposis.' " By W. Bateson, F.R.S. 



** On the Influence of Ozone on the Vitality of some Pathogenic 
and other Bacteria." By Arthur Ransome, M.D., F.E.C.P., 
F.RS., and Alexander G. E. Foulerton, F.R.C.S. Re- 
ceived January 12,-^Read February 14, 1901. 

The influence of ozone on the vitality of bacteria is a matter which 
has received the attention of several investigators. But, on reviewing 
the records of the results which have been arrived at, it is obvious that 
such results have not always been consistent. 

VOL. LXVnL F 



r)6 J.)r. A. Ranaoiue and Mr. A. G, 11. Fouleitoii. 

We detorminc<l, therefore, to investigiite this question anew, in the 
hope of Ixjing able to come to :\ definite conclusion. The matter 
seemed to us to be one of considerable importance, since if ozone were 
possessed of the bactericidal properties which have been attributed to 
it by more than one investigator, the gas might prove of much value 
in solving one of the most unsatisfactory problems which have to be 
dealt with in the practice of modern sanitation, that is to say, the 
disinfection of rooms after the occurrence of infectious disease. Ozone 
can now be conveniently pro<iuced in large quantities, and, if efficient, 
would l>e admirably adapted to effect the purpose in view. 

The question of the bactericidal ivction of ozone wiis especially brought 
into prominence by the classical work of Downes and Bliuit, embodied 
in communications mmle to this Society in 1877 and 1878.* Working 
with impure cultures of bacteria, these investigators showefl that direct 
sunlight in the presence of atmospheric air was capa})le in some cases of 
preventing in greater or less degree, or in other cases of absolutely 
inhibiting, the growth of the jwirticular Iwicteria experimented with ; and 
that not only might growth 1)c inhibited, but that the bactei-ia them- 
selves might be actually destroyed. Downes and Blunt further 
showed that so far as the destruction of bacteria is concerned the 
blue and violet rays of the spectnim are more effective than the red 
rays, that the interposition of a layer of water is sufficient to protect 
the bacteria to a certain extent, and that direct sunlight acting i* 
vaau) may fail to destroy sporing l>actcria. 

Whilst this work of Do^nies and Blunt has l>een fidly confirmed and 
amplified in certain directions by the work of others, no satisfactory 
explanation has yet I>ecn arrived at as to exactly how it is that baeteris 
are destroyed under these conditions. The explanation that the 
result is a direct effect of the sun's rays — of heat — has been shown to 
be untenable ; and it has therefore been Jissumed that the destruction 
is effected by chemical rather than by physical action ; that it results from 
an active oxidation of the substance of the bacteria by ozone, produced 
by the action of sunlight on atmospheric air. Others have regarded 
peroxide of hydrogen as the active agent. 

Amongst the experiments which have been carried out in order to 
test this assumed bactericidal action of ozone, we may particulariy 
mention those of Chapuis,! Sonntag J, and OhlmiilIer.§ Chapuis filtered 
air through cotton wool, and then exposed plugs of the wool nith 
the contained bacteria to the action of ozone. The plugs were after 
wards incubated in a nutrient wort solution, which remained sterile. 
Control plugs of the wool which had not been subjected to the action 

• * Roy. Soc. Proc./ vol. 2fi, p. 488 ; vol. 28, p. 190 ; toI. 40, p. 14. 

t * Bulletin do la Societc Chimique,' 1881, Toinc 35, p. 290. 

J • Genlralblntt fur Buktcriologie.' Erste Abteilung, Band 8, p. 778> 1890. 

§ * Arbeitcn a. d. Kaiserl. Gesundhoitsamte,* 1892, Band 8, p. 829. 



(hi the Infiucn^^ ofOzoiic on th^ Vital it 1/ of sonic Bacteria, H? 

of the ozone, gave rise to a free growth of bacteria, when incubated 
in the same medium. Sonntag and Ohlmiiller's experiments, on the 
other hand, seemed to show that ozone in the dry state had little or 
no action on bacteria, but was capable of destroying them when passed 
through water containing them. Thus B, ajUhracis, suspended in 
distilled water, was destroyed after air containing 9*6 millegrammes 
of ozone per litre had been passed through the mixtiu'e for ten 
minutes. A sporing culture of the same bacillus was killed by pass- 
ing air containing 15*2 milligrammes of ozone per litre through the 
water for ten minutes. If, however, organic matter, such as blood 
serum, were added to the water the results were different; and it 
seemed that under these latter conditions the most part of the ozone 
was expended in oxidation of the dead organic matter present, whilst 
the bacteria were little if at all affected. 

Our experiments were planned with the view of ascertaining whether 
ozone applied in large quantities, either in a mixture vrith atmospheric 
air or with pure oxygen, has in reality a destructive influence on 
bacterial life, and especially whether it has any such influence under 
conditions which would enable it to be used for practical purposes of 
disinfection. 

The experiments have included the testing of the action of ozone, 
^1) on the vitality of certain pathogenic and saprophytic bacteria, 
and (2) on the virulence of one pathogenic species. For the purposes 
of the latter test, we decided to test the action of the gas on B, tnber- 
tulosiSy an organism which is known to be readily affected by the 
direct action of ordinary chemical agents, and one which numerous 
•experiments would lead us to believe is very susceptible to the action 
of direct sunlight (Koch,* Eansome and Delepine,t and Jousset)4 

Experiment L — In our first experiment, culture tubes with " sloped " 
surface of nutrient agar or gelatin were inoculated with various 
bacteria; a mixtiu-e of atmospheric air and ozone was passed con- 
tinuously over the inoculated surface for a period of at least four 
hours, commencing twenty-four hours after the tubes were inoculated. 
The tubes were then incubated at appropriate temperatures, and the 
result compared with that obtained in control tubes which had been 
inoculated from the same stock cultures at the same time. 

In detail the following was the procedure carried out : — The culture 
tabes were of the ordinary 15 x 2 cm. size, into the sides of which short 
pieces of 0*75 cm. calibre glass tubing had been blown in such a way 
that they opened into the lumen of the culture tubes about 3 cm. from 
the bottom and just above the lower level of the sloped nutrient 

* ' Ueber bacteriologuche Forschung/ Introductory Address, Tenth Inter- 
national Medical Congress, August 4, 1890. 
t • Eoy. 80C. Proc.,* toI. 56. 
I * Comptes Rendus de la Society do Biologie/ 1900, Tome 52, p. 8B4. 



58 



Dr. A. liansoiae and ilr. A. G. 1». Foulertou. 



surface, and allowed the ozonised air to escape after passing over the 
Imcteria. The culture tuhes were closed at the upper end by a piece 
of cork through which passed a short length of the 0*75 cm. tulnng, 
which formed the inlet for the ozonised air. 

The inlet and outlet tuhes were loosely plugged with cotton woo!, 
and by means of them and short lengths of india-mbber tubing the 
cultive tubes could Ije connected up in series, and sterile ozonised air 
drawn over the inoculated surfaces. 

Such culture tuljes were inoculated Avith the follo\iing bacteria : — 

Glyccrin-agar tubes (Nos. 1 to 6) with BncUhis tuhercnlosia. 



Nutricnt-agar 
Nutrient-gelatin 



(Nos. 7 and 8) 
(Nos. OandlO) „ 
(Nos. 11 „ 12),, 
(Nos. 13 „ 14),, 
(Nos. 15 „ 16) „ 



Bacillus mallei. 
Bodllus iliphthcrUf, 
Bnnlhm onthraris (sporing). 
Btwllm fj/phosv^. 
Micrococcus nieliU'^fiitiit. 



(Nos. 17 „ 18) „ Micrococcus cavdic^ins. 



The tulies weie then arranged in two series, those numl>ered 1 to 12 
1)eing connected up in one scries and those numbered 13 to 18 in 
another. The two series of tulies were then placed in a room of about 
900 cubic feet capicity and ozone was generated in the air of the room 
by meiins of four small " ozonisers," a 3-inch spark Kuhmkorff coil and 
an accumulator battery being used. The "ozonisers" were kept 
working for four hours, during the whole of which time ozonised air 
wsis slowly aspirated through the tu1)es. At the end of four hours the 
arrangement of the tubes was altered ; a fresh series, including thoee 
niunbered 3 to 12 and 15 to 18, being connected up, and pure oxygen 
charged \nth ozone was forced through the tu1)es for a period of thirty 
minutes. During this half-hour ozonised air was still being drawn through 
tubes 13 and 14. The culture tul>es were then incubated, Nos. 1 to 12 
at 37' C, and Nos. 13 to 18 at 22"^ C, the respective control tubes 
being incubated with them. The result of the experiment was that in 
the case of two out of the seven species tested, there seemed to have 
been some slight retardation of growth iis the result of the exposure to 
the ozone ; that is to say, in the cjise of one or l>oth of the duplicate 
tubes contJiining Bfmllus malUi and Bddllm diphtheria', the growth of 
the experimental cultures seemed at first to l>e rather slower than 
it was in the corresponding control tubes. But at the end of eight 
days' incubation all difference between the experimental and contxxd 
tu})es had disappeared, and gi'owth was equal in both sets ; and iB 
further exjjeriments this effect was not obvious. In the case of the 
other five species not the slightest effect could be observed as the result 
of the exposure. This experiment was carried out under conditions 
which, although they might approximate to those which would prevail 
in the actual use of ozone as an aerial disinfectant, were not adapted to 



On the Injluence of Ozmie on tlte Vitality of some Bacteina. oO 

test the action of ozone on bacteria, apart from an important disturbing 
factor. The bacteria were submitted to the action of ozone in the 
poresence of a large amoimt of dead organic matter, and it was quite 
•conceivable that such an amount of the ozone might have been decom- 
posed in the oxidation of the dead organic matter that but little had 
been left to exert any action on the living bacteria.* 

Experimeni IL — In this experiment we endeavoured to test the action 
of ozone on the bacteria in the absence — so far as we could ensure the 
■condition^-of dead organic matter. The same culture tubes were used, 
but instead of inoculating agar or gelatin nutrient surfaces we inoculated 
small blocks of plaster of Paris from stock cultures of the various 
bacteria tested. These plaster of Paris blocks when inoculated were 
placed in the culture tubes, and the inlet and outlet tubes were plugged 
with fine Italian asbestos fibre instead of with cotton wool. And instead 
of passing the same current of ozone over a series of tubes in succession, 
we connected each tube separately with a main feeding pipe with 
lateral branches, the respective tubes being held in contact by pieces 
of india-rubber tubing. Thus each culture tube had a fresh supply 
of ozone. Ozone was generated as before, and passed over blocks 
inoculated from stock cultiu'es of the following : — 



1. 


Staphylococcus pyogenes aureus. 


7. 


Bacillus typhosus. 


2. 


Streptococcus pyogenes. 


8. 


Bacillus coli communU. 


3. 


Micrococcus melitensis. 


9. 


Bacillus pyocyaneus. 


4. 


Bacillus mallei. 


10. 


BacUlus pneumoniir 


5. 


Bacillus diphtherice. 




(Friedlander). 


6. 


Bacillus anthrads 


11. 


Bacillus prodigioms. 



(from sporing culture). 1 2. Succliaroniyces albiruns. 

Duplicate tubes were inoculated with each organism, and a con- 
tinuous current of air was pumped over the ozoniser, which was 
enclosed Mrithin a glass cylinder connected with the main feeding 
tube, and then through the culture tubes for a period of thirty minutes. 
The actual amount of ozone used was not estimated, but iodide of potas- 
sium and starch paper held over the outlet tubes gave a positive reaction 
within sixty seconds of the commencement of the experiment. The 
small plaster of Paris blocks were then shaken up in tubes containing 
3 c.c. of nutrient broth, from the broth tubes loopfuls were transferred 
to other media, and the growth obtained after incubation compared with 
the growth on control tubes. 

The results obtained on incubating the sub-cultures made it evident 
that none of the bacteria had been aifected by the ozone in such a way 
48 to impair either their capability of growth, or, in the case of the two 

* We are indebted to Mr. Bridge, chemist, of Bournemoath for ossistAnce in 
the working of the ozonising apparatus used in carrying out this eiLpenmeiit. 



60 



l)r. A. Kaiisouie and Mr. A. G. li. Foulertoii. 



chromogenic bacteria, their function of pigment production. The patho- 
genic action of a broth sub-culture of B, mallei, after the ozonisation, was 
tested by intra-peritoneal inoculation of a male guinea-pig ; an ordinary 
infection vrith characteristic lesions followed, the animal dying within 
forty-eight hours. 

Experiment III, — We now decided to subject the bacteria to a rather 
more severe test than had been involved in the two preceding experi- 
ments. The ozone was produced by passing oxygen under pressure 
from a cylinder over a powerful "ozoniscr," enclosed within a glass 
cylinder, and then into the main feeding tube, as in the previoos 
experiment. The current used was an alternating one direct from the 
street main. Small pieces of porcelain were, after inoculation with 
the following bacteria, placed in the culture tubes : — 



1. 


Sarcina ventriciili. 


7. 


Bacillus afithrads 


2. 


Micrococcus TnelUenm. 




(from old sporing culture on 


3. 


Micrococcus candiraiia. 




potato). 


4. 


Bacillus mallei. 


8. 


Bacillus Ujp]wsu^<. 


5. 


Bacillus diphthej'im. 


9. 


Bacillus coli communis. 


6. 


Bacillus anihracvi 


10. 


Bacillus pyocyaneu^^. 




(from twenty-foiu" hour old 


11. 


Bacillus pteumoniof. 




culture in broth, non- 


12. 


Barillvs prodigiosim. 




sporing). 







Duplicate tubes of each species were used for the experiment, the 
first attempt to carry out which resulted in failure, owing to the 
iiction of the ozone on the pieces of india-rublxjr tubing by which 
the branches of the main feeding tu])e and the inlets into the culture 
tubes were held in contact. Before the mixture of ozone and oxygon 
had been passed into the series of cidture tubes for ninety seconds^ 
every piece of india-nibber tubing Wiis cut through, as if \vith a knife. 
The joints were, therefore, made with pieces of l)ored cork, and the 
experiment repeated. The mixture of ozone and oxygen was passed 
through the tubes at the rate of 1*5 litre per minute for a period of 

thirty minutes ; the yield of ozone, as estimated by titration with -- 

iodide solution, amomited to 0*072 gramme per minute. The percent- 
age amount of ozone was therefore about 2 '4 by volume. At the end 
of thirty minutes the pieces of porcelain were dropped into tubes of 
nutrient broth and incubated. On comparison Ynth the various con- 
trols it wfis ol>vious that the ozone had not affected the bacteria in such 
a way as to impair either their capability for growth, or, in the case of 
the chromogenic organisms, their power of producing pigment. The broth 
sub-culture of B. anthracis (non-sporing) after forty-eight hours' incuba- 
tion at 37' C. was tested on a white mouse, and proved to be of normal 



On the Influence of Ozone on the Vitality of same Bacteria, 61 

virulence ; 0*25 c.c. of the broth culture, injected into the peritoneal sac, 
killing the animal within twenty-four hours in typical fashion.* 

Experimeid IF, — ^Although it seemed to have been conclusively 
proved by the experiments of Ohlmiiller, already referred to, that ozone 
was capable of considerable bactericidal action when the organisms 
were suspended in certain fluids, we determined to carry out a single 
experiment, using milk as the medium. We used milk because we 
considered that it would, as containing a large quantity of organic 
matter, test the bactericidal action of the gas severely. 

Five flasks, each containing 125 c.c. of milk, were prepared as fol- 
lows : — 

Flask 1 contained sterilised milk which had been inoculated with a 
culture of B, anthracis (sporing). 

Flask 2 contained sterilised milk which had been inoculated witli 
a non-sporing culture of B. anthracis. 

Flask 3 contained ordinary fresh unsterilised milk, to which a 
quantity of a broth culture of B. prodigiosus had been added. 

Flask 4 contained ordinary fresh unsterilised milk. 

Flask 5 contained a sample of commercial " sterilised ** milk which 
had " gone bad " owing to the presence in pure culture of an anaerobic, 
sporing, butyric acid forming bacillus. 

A current of oxygen containing the same proportion of ozone as that 
used in Experiment III was passed through the milk in each of the 
flasks for a period of twenty minutes at the rate of 1 '5 litres per minute. 
Loopfuls of milk were then taken from each flask, transferred to 
various culture media, and incubated under both aerobic and anaerobic 
conditions ; the flasks vrith the bulk of the milk still remaining in them 
were also incubated. 

In the result, it was found that the contents of flasks 1, 2 and 5 
were sterile of bacteria. The milk used for flasks 3 and 4 was taken 
from the same sample, and on incubation of the sub-cultiu*es aftei- 
ozonisation a growth of a mould-fungus was obtained from each flask ; 
from flask 3 a very free growth of the mould was obtained, but neither 
B. prodigiosus or any other bacterium ; from flask 4 a few colonies of a 
coccus were obtained in both aerobic and anaerobic cultures in addition 
to the mould which was present apparently in less quantity in the con- 
tents of flask 4 than it was in the contents of flask 3. In the case of 
the sub-cultures from flask 3, the growth of the mould was very rapid, 
and soon covered the surface of the medium, and so possibly checked 
the growth of the coccus which appeared on the sub-cultures from 
flask 4, in which the mould growth was less abundant. 

A loopful of the milk used for flasks 3 and 4, taken before ozonisa- 
tion and smeared over nutrient agar, gave, on incubation at 22** C, 

* We are indebted to Mr. Wood Smith, F.I.G., for assistance in tlie working of 
the ozonising apparatus used in this experiment. 



62 Dr. A. Eausoiue aud Mr. A. G. R FoulertoiL 

a large number of colonies of different bacteria ; and it was apparent 
that the exposure to ozone had resulted in the destruction of a large 
majority of these, although complete sterilisation was not obtained as 
in the case of flasks 1, 2, and 5. 

At the end of the experiment, the milk in flasks 1, 2, 3, and 4, 
although not changed in appearance, had acquired an extremdj dis- 
agreeable taste and smell, which was in all probability at least partly 
due to the development of fatty acids. It seemed therefore posaiUe 
that in the case of these milks, not only might the ozone have had a 
directly injiurious action on the bacteria, but it might also have affected 
them indirectly by producing from the natural milk various bodies 
which might themselves also have to be considered as factors in the 
experiment. 

The milk in flask 5 was in a late stage of decomposition and pos- 
sessed of a most offensive odour ; it was noticed that the offensiveness 
of this milk was considerably reduced after the passage of the ozone. 

ExpeiimeMt F, — Our next experiment was made in order to ascertaiD 
whether ozone had any influence on the virulence as apart from the mere 
vitality of B. iubercuhsis, and was carried out in the following way :— 
Sputum rich in the specific bacillus was smeared over stripe of filter-paper. 
These strips were then dried, and afterwards exposed for varying periods 
to the action of highly-ozonised air. The exposure was ensured by 
pinning out the strips on a board, which was hung about 6 feet from 
the same ozonising apparatus as that used in Experiment I, and in the 
same room. The apparatus was set at work two hours before the 
exposure of the sputum was commenced, and was continued without 
intermission throughout the experiment. When the exposure was 
commenced the air of the room was so highly charged with ozone as to 
be extremely impleasant, and not respirable by anyone for more than a 
few minutes at a time. After undergoing exposures of the several 
durations given in the table below, the strips of infected paper were 
moistened, stretched out on glass, and the surface which had been 
smeared with the sputum w;is scniped oif lightly with the edge of a 
knife. The scraping from each strip was collected in a cubic centi- 
metre of sterilised normal saline solution, and doses of 0*2 c.c. of the 
emulsions thus obtained were injected under the skin of the inguinal 
fold in guincfi-pigs. As controls, other guinea-pigs were siinilarly 
inoculated with some of the crude sputum, and also with the scrapingi 
from an infected strip of paper which had not l)een previooaly 
ozonised. Fourteen animals in all were inoculated; the foUowing 
table gives their weights and the nature of the emulsion used for 
each : — 



On the Injhieiice of Ozoiic on the Vitality of sonu Bacteria. 63 



Animal. 


Weight. 


Inoculated with — 


Guinea-pig I.. 


grammes. 
500 


Small quantity of crude sputum. 


11.. 


470 


>» » »f 


III.. 


390 


Emulsion from filter-paper, not ozonised. 


IV.. 


S89 


a }» 1 


t 


V • 


420 


»> )» > 


y ozonised \ hour. 


VI.. 


436 


It )> ) 


» i » 


VII.. 


450 


t> » > 


„ 1 » 


VIII.. 


455 


}f » } 


„ 1 ,. 


IX.. 


890 


>t >* t 


, V 2 hours. 


X.. 


450 


» >» » 


f >» 2 „ 


XL, 


870 


f» »» » 


.. 4 „ ' 
„ 4 „ 


XII.. 


870 




XIII.. 


410 


»» >> » 


„ » M 


XIV.. 


370 


»t »» 1 


,. 8 » 



The various animals were either allowed to die naturally or were 
lolled with chloroform after definite signs of tubercular infection had 
developed. And it may at once be said that a severe infection occurred 
in all the animals ; there was not the least indication that the ozonisa- 
tion had exerted any eflFect whatever on the virulence of the bacilli. 
As examples, we may mention the following animals : — Guinea-pig 
No. I died on the twentieth day after inoculation, with a caseous 
abscess in the flank, infected mesenteric glands, and tubercles in the 
spleen ; guinea-pig No. II was killed on the twenty-second day after 
inoculation, and was found to be in a similar condition ; guinea-pig 
No. XI died on the twenty-second, and guinearpig No. XIV on the 
twenty-third day, both being again in a similar stage. The presence of 
the specific bacillus in one or other of the internal lesions was proved 
in the case of e^^^ery animal on the list. 



Conclusions, 

Our experiments have made it clear that ozone in the dry state, and 
in such strength as we used it, has no appreciable action on the vitality 
of the various bacteria experimented with, and, so far, our results arc 
in accordance with those of Sonntag and Ohlmiiller. Nor did a 
prolonged exposure to the action of ozone diminish in any way the 
pathogenic virulence of B, tuberculosis in sputum, as shown by 
Experiment V. Single experiments would also tend to show that 
ozone can have little, if any, effect on the pathogenic virulence of 
B. mallei and B, anthrads. 

On the other hand. Experiment IV would appear to confirm the 
-conclusion arrived at by Ohlmiiller as to the bactericidal property of 
ozone when passed through a fluid medium containing bacteria in 
suspension. 



04 Messrs. B. Moore and W. H. Parker. 

A comparison of the inacti\4ty of ozone as a disinfectant in the 
(Iry state ^dth its action in the presence of water suggests a super- 
ficial resemblance with other gases, such as chlorine and sulphur 
dioxide. In the absence of further experiment, however, it would not 
1)0 possible to press the analogy too closely. 

In the dry state, and under the conditions in which it occurs in 
nature, ozone, then, is not capable of any injurious action on bacteria 
so far as can be judged from our experiments ; and we conclude that 
any piuifying action which ozone may have in the economy of nature 
is due to the direct chemical oxidation of putrescible organic matter^ 
and that it does not in any way hinder the action of bacteria, which 
latter are, indeed, in their own way, working towards the same end as. 
the ozone itself in resolving dead organic matter to simpler non- 
putrescible substances. 



"On the Functions of the Bile as a Solvent." By Benjamin 
Moore and William H. Parker. Communicated by Professor 
SciiAFER, F.R.S. Eeceived January 24, — Bead February 14,. 
1901. 

The purpose of the biliary secretion and the uses of that fluid itt 
digestion and otherwise have furnished much material for discussion to 
the physiological chemist, and the discussion has given rise to many 
ingenious but widely different theories. 

The bile, unlike all the other digestive fluids which are secreted into 
the alimentary canal, has no specific action upon any of the three 
classes of food-stuffs. It contains small amounts of cholestearin and 
lecithin, and of other substances which are obviously to be regarded 
as excretory in character. It is necessary in the intestine for the com- 
plete absorption of the fats in normal amount, but even in its absence 
a considera])lo amount of fat can still be absorbed. The constituents 
which it contains in solution in largest quantity are the sodium salts of 
certain acids called the bile acids, and these bile salts are not excreted,, 
but are realisorbed, and undergo a circulation in the blood known aa 
the circulation of the bile. 

These few statements briefly summarise our experimental knowledge 
iis to the action and physiological properties of the bile, and have given 
H basis to many theories. 

It has been argued by some from the fact that bile contains no- 

rligeative enzyme, and from the presence in the fluid of certain con- 

js- tituents which are certainly excretory, that the bile is to be regarded 

^'jurely as an excretion ; but this ^aew gives no explanation of the re- 

r' ^sfibsorption of the bile salts, which arc the most abundant constituents 



On the Functions of the Bile as a Solvent, (>r> 

By others the bile has been regarded as an anti-putrefactive, althoug]> 
it readily undergoes putrefaction itself. Others, without much experi- 
mental proof, have suggested that it stimulates the intestinal epithe- 
liom and increases peristalsis, but even if this be allowed it leaves 
much of the action of the bile untouched. While it is universally 
admitted that bile exhibits at most only unimportant traces of a diges- 
tive action on food-stuffs, some observers state that its presence favours 
and increases the activity of other digestive fluids upon carbohydrates,. 
fats, or proteids, and see in this an important function of the bilc.^ 
On the other hand, it is stated by other experimenters that this aiding 
power of the added bile is no more than can be explained by the altera- 
tion in chemical reaction of the mixed fluid. f 

With regard to the action of bile in favouring fat absorption, one^ 
view which has been held is that the bile alters the physical character 
of the intestinal epithelium when it wets it, and in some physical way 
makes the conditions more favourable for the taking up of emulsified 
fats. Since it is very probable, however, that all the fat is absorbed 
in some soluble form, and not as an emulsion, this theory of biliary 
activity falls to the ground. 

It was first suggested by Altmann,t mainly from histological obser- 
vations, that bile aided fat absorption by dissolving the fatty acids set 
free from the neutral fats in the intestine. Marcet§ had shown before 
this that bile dissolves free fatty acids to a clear solution, and later 
Moore and Rockwood|| determined the solubilities of fatty acids in bile,. 
and further demonstrated that in some classes of animals a certain 
amount of the fat was absorbed as dissolved free fatty acid. 

The latter authors, while admitting that a considerable amount of 
absorption of fat as dissolved free fatty acid occm*s in carnivora, and 
insisting upon the importance of bile as a solvent in this connection, 
showed from a consideration of the reaction of the intestinal contents^ 
during active fat absorption that in other species of animals practically 
aU the fat was absorbed as dissolved soaps. Even in carnivora it was 
farther shown that in addition to the absorption as free fatty acid dis- 
solved by the bile, a considerable amount of absorption as dissolved 
soaps takes place. 

The soaps formed in the intestine during the digestion of fat are 
chiefly sodium soaps. Now it has universally l)een taken for granted 
that these are easily soluble in water, and no one has considered any 
action of the bOe as necessary to their solution in the intestinal con- 

• RiMjhford, * Journ. of PliyBiology/ 1899, vol. 25, p. 165. 
t Chittenden and Albro, * Amer. Journ. of Physiol./ 1898, vol. 1, p. 307. 
t * Arch. f. Anat. u. Physiol.,' 1889, Anat. Abth. Supp. Bd., p. 86. 
§ * Eoj. Sec. Proc. Lond.,' vol. 9, 1868, p. 306. 

II *Roj. Soc. Proc.,' vol.60, 1897, p. 438; * Journ. of Physiol.,' vol. 21, 1807^ 
p. 58. (In this paper the literature of the subject is given.) 



66 Mes8i*s. B. Moore and W. H. Parker. 

tents. But the process of preparing the sodium soaps easily demon- 
strates that the mixed sodium soaps prepared either from heef or mutton 
suet are only veiij sparingly soluble in water. When the mixture obtained 
by boiling the fat is thrown into cold water, practically none dissolves, 
and the excess of alkali can easily be washed oflF in this way. An 
increase in the amount of oleate present raises the solubility in water, 
80 that a mixture of soaps obtained from pig's fat cannot be separated 
in this way. When the mixed soaps derived from beef or mutton fat 
are boiled with water, they do dissolve to a greater extent ; but the 
solution sets, on cooling, to a stiff jelly, even when it contains as little 
as 2 per cent, of the mixed soaps. 

It occurred to us, therefore, that it would be desirable to make com- 
parative quantitative experiments cOs to the solubilities at body tern- 
pei'ature of such soaps in water and in bile respectively, in order to 
determine whether bile possessed any fimction as a solvent in soap 
absorption from the intestine. Opportimity was also taken to prepare 
4ind test the solubility quantitjitively of the so-called " insoluble soaps " 
of calcium and magnesium, as well as of the separated and purified 
oleates, palmitates, and stearatcs of sodium, calciiun, and magnesium. 

Attention has previously been given to the solubility of the magne- 
sium and calcium soaps, so far as we arc aware, only in a qualitative 
fashion ; and the unqualified statement has in consequence been made 
by Neuraeister* that these soaps are dissolved in the intestine by the 
Agency of the bile. 

There is, in addition to the solvent action of bile upon the various 
fatty derivatives in the intestine, another point of view from which we 
may regard the bile as a solvent, and ascribe to it a very important 
fimction connected with the excretion into the intestine from the liver 
of substances insoluble in water. It is well known that the bile con- 
tains cholestearin and lecithin, and although these bodies are not present 
in largo percentage, they occur in greater qmmtity in the bile than in 
any other fluid in the lx)dy, and further this is the only channel by 
which these important degradation-products of metabolism are removed 
from the body. 

Although the presence of these substances in the Idle has long l)een 
known, no one, so far as we are aware, has drawn any inferences as to 
Avhy they are excreted by the bile rather than any other excretory 
c'hannel, nor recognised the importance of the change in the physical 
properties of the bile, whereby it is adapted for carrying off these 
waste products to the intestine, and so acquires a specific function 
possessed by no other fluid in the body. 

Both lecithin and cholestearin are insoluble in water, and hence 
cannot be thrown out of the body in simple «aqueous solution. This 
fundamental fact suggests inquiries as to how these substances are 
* * Lclirbucli dor phvsiologisclien Chcinie,* Jena, 1897, p. 221. 



On t/ic Functions of tlie Bile as a Solvent. G7 

carried in solution to the liver cells to be there excreted, as to how 
they are preserved in solution in the bile, and as to the extent to which 
each of them is soluble in that fluid. 

Experiments were accordingly arranged to test the powers of the 
bile salts as a solvent for these two substances, which taken in con- 
junction with the known facts as to the reabsorption and circula- 
tion in the blood of the bile salts cast a considerable light upon the 
questions above outlined, and furnish a rational explanation of the 
so-called " circulation of the bile." 

It is, in our opinion, in this property of acting as a solvent for sub- 
stances which are insoluble in water, that bile has its main if not its 
only function, both in excretion and absorption. 

Any other properties which have been ascribed to the bile are of 
very minor importance compared to this one. It enables us in the 
firtst place to explain clearly the pait played by bile in fat absorption, 
for our experiments show not only that the solubilities of the soaps are 
eonBiderably increased, but, which is of more importance still, that 
they are dissolved by the bile in a different physical condition from 
that in which they are held in solution by water alone, as is shown by 
the altered physical properties of the solution. Further, free fatty acid 
could not be held in solution in the intestine in the absence of bile. 
Again, it is impossible to see how such substances as cholestearin and 
lecithin could be excreted in the absence of some vehicle conferring 
lolubility upon them. 

Experimental MdJioJs. 

The bile salts used in our experiments were prepared by a usual 
modification of Plattner's method from ox bile. The bile was con- 
centrated to a syrup on a water-bath, mixed into a paste with animal 
charcoal, extracted with absolute alcohol, filtered, and ether added to 
commencing precipitation. On standing, the bile salts were obtained 
in crystalline spherules, and these were purified by dissolving in 
(ilcohol and reprecipitating with ether. 

The mixed sodiimi soaps employed were obtained by saponifying 
beef suet. Much labour was expended on various attempts to prepare 
thcsse in a pure form ; such as obtaining the free fatty acids in ethereal 
solution and neutralising with alcoholic potash, or extracting the soaps 
inth hot alcohol in a Soxhlet apparatus and cooling out from the 
Ucohol. These methods have practical difficulties, however, on 
M^count of the varying solubilities of the constituent salts in the organic 
lolvents. Accordingly, a simpler method was found to yield better 
results. The fat was first saponified by slight excess of caustic soda, 
Mid the mixture of soaps thrown into a large excess of cold water,* 

• Saturated Boliition of sodiam chloride was at Crst used, but it was found that 
tlic mixed sodium soaps were so insohiblc in cold water that no suc\\ ft«A\tv« 



«jS Messrs. B. Moore and W. H. Parker. 

which (li^fholves out the surplus of alkali and inorganic salts. The 
rfoaps were next converted into free fatty acids by treatment with 
dilute hydrochloric acid, and the mixture of fatty acids was thoroughly 
washcfl by warming with water. The free acids were again con- 
verted into soaps by very slight excess of caustic soda, dissolved in 
lioiling water, precipitated by cooling, washed with cold water, dried 
in a water bath, powdered, and kept in a glass-stoppered bottle. 

The mixed calcium and magnesium soaps were prepared from these 
by precipitation from solution in hot water with calcium chloride and 
magnesium sulphate respectively, washing thoroughly with water, and 
4lrying on a water bath. 

The pive oleic acid and oleates used were prepared from a sample 
of pure oleic acid by Merck. 

The pure palmitic acid was obtained from bereberry tallow by 
repeated partial recrystallisation from alcohol until a constant and 
accurate melting point was obtained. The sodium soap was obtained 
by neutralising with caustic soda and recrystallising from hot alcohol ; 
the magnesiiun and calcium soaps by precipitation of the sodium salt 
in hot aqueous solution by the appropriate salts, washing by decantiu 
tion ^lith cold water, and drying. 

The pure stearic acid and stearates were similarly prepared from 
commercial stearin, and their purity tested by melting-point deter- 
minations for the free acid. 

The lecithin used was prepared from yolk of egg by the follow- 
ing modification of the method of Hoppe-Seyler : The yolks were 
.separated, l>eaten up into a common mass and extracted with five times 
their volume of 95 per cent, alcohol at a temperature of 50* to 60* C. 
for alx)ut two hours. The precipitated proteid and membrane was 
separated off by pressing through cheese cloth, the filtrate was allowed 
to cool to al)out 30^ C. and separated from a certain amount of fatty 
oils which l)ecame pressed through along with the alcoholic extract. 
The alcoholic extract was evaporated down to a synip at a temperature 
of about 60^ C. on the water-bath, and then taken up in a small 
volume of absolute alcohol at a temperature of 40* to 50' C. This 
extract was next surrounded by a freezing mixture and kept at a 
temperatuie of - 5"* to - lO'* C. for some hoiu^, which precipitates 
the greater part of the lecithin. This was removed by decantation 
and filtering through a chilled funnel, purified by again dissolving in 

prcoipitunt is required. Not even any Mxlium oleate is disBolyed bj the oold 
* water, as can bo nliown by first throwing into cold water, then remoying the soap 

and saturating the water with sodium chloride, when scarcely a trace of a pieoi- 
pitate is obtained. Nor are a<*id e>oap8 formed by tliis method of preparation, on 
liccount of dissociation of the alkali, for on incineration of the soaps and titratioii 
of the rotfiduo as sodium carbonate, we haTc obtained almost the theoretical yields 
required for neutral 8oaps. 



On the Fmictiotis of the Bile as a Solvent, 69 

s small volume of absolute alcohol, and once more cooling out of solu- 
tion. The final product was dried in a desiccator over sulphuric acid 
for some days. 

In the case of cholestearin the figures obtained for the solubility 
were so low, that pure cholestearin preparations were made from 
several sources in order to make certain of the result; but all the 
specimens gave a like result. 

The cholestearin first used was prepared from a laboratory specimen 
by repeatedly recrystallising from ether and from hot alcohol. The 
second specimen was obtained by repeated recrystallisation from hot 
jJcohol and ether of the residue after talking out the lecithin from the 
hot alcoholic extract of egg yolk by means of a small volume of 
absolute alcohol as above described. Large characteristic cholestearin 
crystals were easily obtained by this, method in great abundance. A 
third specimen was similarly prepared from ox brain, and a fourth from 
human gallstones by the usual method of extraction. 

Comparative determinations were made of the solubilities in distilled 
water, in 5 per cent, aqueous solution of bile salts, in 5 per cent. 
aqueous solution of bile salts plus 1 per cent, of lecithin, and occa- 
sionally in ox bile. Two methods were employed in carrying out 
the determinations, which were all made at a temperature as close to 
that of the human body as possible, viz., at 37"* to 39*' C. 

In one method, an excess of the substance of which the solubility 
was to be determined was heated to a temperature of 50' to 60** C. 
with the solvent; the mixture was allowed to cool to the required 
temperature, and then filtered through paper in a funnel kept at body 
temperature by a warm jacket. It was afterwards tested that the 
filtrate became clear, when it was once more heated to body tem- 
pottture. 

The percentage dissolved is then estimated by determining the 
amount of dissolved substance in a given voliune, say 5 c.c, of the 
filtered solution. This is done by evaporating to dryness, extracting 
the fatty acids with ether (in the case of the soaps, after first convert- 
ing into free fatty acids by the action of a mineral acid), and weighing 
after evaporating off the solvent. 

This method has some practical disadvantages which have precluded 
its use except in the case of the determination of the solubility of the 
sodium soaps in bile. In the first place, a considerable amount of 
both solvent and solute must be used in order to obtain a workable 
quantity of filtrate. It is also difficult to filter with some of the sul)- 
stances tested, and on extraction of the evaporated solution with ether 
it is often impossible to obtain a clear ethereal solution. This method 
has therefore only been carried out in the case of the sodium soaps and 
bile. Here it has been used to determine the inaximum amount which 
ean be taken up by the bile from such a natiu'ally-occurTing xavxlxjn^ oi 



70 Messrs. B. Moore and W. H. Parker. 

soaps as is obtained in the saponification of beef fat. When such a 
mixture is submitted to the solvent action of the bile it is found that 
more sodium oleate than palmitate or stearate is taken up, as is shown 
in the considerable reduction which is obtained in the melting point of 
the mixture of fatty acids dissolved and re-obtained from the bile as 
compared with the melting point of the fatty acids obtained from the 
mixed soaps before being acted upon by the bile. In fact, it is only 
when sodiiun oleate is also present that sodium palmitate and stearate 
are taken up by the bile in appreciable quantity. As a result of this^ 
the figures obtained by this method, in the case of the mixed sodium 
soaps, must only be taken as indicating the maximiun amount of soaps 
which the bile is capable of taking up from such a mixture at body 
temperature, and it must be remembered that the portion taken up has 
not the same composition as the mixture extracted, and that the solu- 
bility of the residue gradually decreases as the percentage of palmitate 
and stearate in it increase.* 

The second method, which has chiefly been used in making the 
determinations, is to add the substance to be dissolved in small weighed 
portions at a time to a measured volume of the solvent contained in a 
test-tube and kept at body temperature by being immersed in a water 
})ath provided with a thermostat. The mixture is stirred from time to 
time with a glass rod, and the substance to be dissolved is rubbed up 
with the solvent to hasten the process of solution. The amount added 
when solution ceases to be complete is noted, and from this a close 
approximation can be made to the percentage solubility. The approxi- 
mation is the closer the smaller the amount of substance added each ' 
time, and the larger the volume of solvent which is taken. By using 
10 CO. of solvent and adding the substance in portions of 0*01 gramme 
at a time, it is thus possible to determine the solubility within one-tenth 
of a per cent. The method is somewhat laborious in making a first 
determination from the niunber of weighings, but in later determina- 
tions with the same solvent and solute it can be shortened by adding 
at once nearly the total quantity which it is known will be dissolved. 
Reliable results are obtained by this method in the case of determining 
the solubility of pure substances, but in a mixtiu*e of the soaps it gives 
a lower result than the total amount which the solvent will take up 
from the mixture, because the signal for stopping is here that point at 
which the maximiun amount of the least soluble constituent of the 
mixture has been taken up. Thus a slight residue is obtained when 
even as little as 0*5 per cent, of mixed sodium soaps is added to bile at 
l>ody temperature, and a somewhat heavier residue when water is 

• A similar result is seen when the mixed fatty acids or soaps obtained by 
faponifying any naturaUy occurring fat are treated with a solvent in which they 
are nut exceedingly soluble, such an hot alc-ohol, a residue of insoluble stearic acid 
or stearate is finally obtained. 



On the Fund torn of the Bile as a Solvent, 71 

employed as the solvent ; the amount of undissolved residue increases 
as the amount of mixed soaps added is increased, but it is obvious to 
the eye that a considerable amount of the later additions of soap arc 
being dissolved, and, further, a determination of the melting point of 
the mixed fatty acids obtainable from the imdissolved residue proves 
that this consists chiefly of palmitates and stearates. 

This is interesting from the physiological point of view, since a 
similar separation must take place in the intestine, and the oleates Ijc 
abeorbed more readily and more rapidly than the palmitates and 
stearates. 

Eesults. 

1 . Free Fatty Acids. — The mixed free fatty acids obtainable from 
beef suet are practically insoluble in distilled water at body tempera- 
ture. When as little as 0*1 per cent, is added, the greater part remains 
undissolved in the form of melted globules ; but, on cooling down, a 
Eaint opalescence in the fluid indicates a slight degree of solubility. A 
5 per cent, solution of bile-salts dissolves 0*5 per cent, of the mixed 
adds, and a 5 per cent, solution of bile-salts plus 1 per cent, of lecithin 
dBasolyes 0*7 per cent. The effect of the lecithin in increasing the 
■olubility is clearly seen by heating simultaneously in two test-tubes, 
one containing bile-salts alone, and the other bile-salts plits lecithin, 
D*5 per cent, of the fatty acids. The tube containing the lecithin clears 
ftrst, and on cooling the two tubes a heavy precipitate is obtained in 
fcbe case of the bile-salts only, and scarcely any precipitate in the solu- 
tion containing lecithin in addition. 

Oleic add has the following solubilities : — Distilled water less than 
0*1 per cent. ; bile-salt solution, 0*5 per cent. ; bile-salt phis lecithin 
iolution, 4 per cent.* 

Palmitic acid, in distilled water, less than 0*1 per cent. ; in bile-salt 
Solution, 0*1 per cent. ; in bile-salt pltis lecithin solution, 0*6 per cent. 

Stearic acid, in distilled water, less than 0*1 per cent. ; in bile-salt 
tolution, less than 0*1 per cent. ; in bile-salt phis lecithin solution, 
^•2 per cent. 

2. Sodium Soaps. — The mixed sodium soaps of beef suet, tested by 
Hl€ supersaturation method, yield to distilled water 2*23 per cent., 
tod to ox bile (sp. gr. 1027) 3*69 per cent. The solubilities in the 
Kher solvents of the mixed soaps was not determined, because the 
Niustituents, for the reasons assigned above, are not taken up in pro- 
N^ionate quantities, and hence the flgures have little value as quanti- 
^tive results. 

The above figures consequently give merely the maximum uptake of 

'^ The bile-Mlt solutions emplojed invariably contained 5 per cent, of the 
^ixed bile-salts of ox bile, and the bile salt plus lecithin solutions 1 per cent, of 
i^^ihin in addition. 

VOL. LXVni. G 



72 Messiu K Aloore and W. H. Parker. 

soaps by bile from such a naturally occurring mixture, and do not 
moan that a mixture of soaps of unaltered composition is taken up to 
the extent indicated. 

Of much more importance physiologically than the increase in 
ninmirU of soap taken up, due to the presence of the bile salts, is the 
obvious physical change in character of the solution. After filtration 
in each case from the excess of undissolyed soap, a difference is observ- 
able even at body temperature between the two solutions. The solu- 
tion of slightly over 2 per cent, of soaps in distilled water is opalescent 
like a starch or dilute glycogen solution, while that of over 3 per cent, 
of the same toape in bile is limpid and clear. On allowing the two 
solutions to cool to the temperature of the room, the physical differ- 
ences become much more marked, for the more dilute distilled water 
solution sets into a stiff jelly so that the containing flask can \ie turned 
upside down without causing any alteration in the shape of the jelly, 
while the solution in bile remains quite limpid, and only a small part 
of the dissolved soaps passes out of solution as a firiely granular predpir 
tate. The formation of a jelly on cooling, in the case of the distilled 
water solution only, is not due to the fact that a larger quantity of 
soaps passes out of solution here on cooling ; for no matter at what 
temperature higher than that of the body bile be saturated with the 
mixture of soaps, and hence no matter how much soap passes out of 
solution on cooling, it never forms a jelly, but always a precipitate and 
a clear supernatant fluid. 

Now the formation of a viscid solution iand ultimately of a jelly is 
one of the general properties of colloidal solutions, and hence the 
above-described experimental I difference in behaviour prol)ably indi- 
cates that soaps in solution in distilled water are in a more colloidal 
condition, and accordingly in a less diffusible and absorbable condition, 
than when dissolved in the presence of bile-salts. 

Smlium okate has the following solubilities — in distilled water, 5*0 per 
cent.; in bile-salt solution, 7*6 per cent. ; in bile-salt jt^/z/x lecithin solu- 
tion, 11 6 per cent. 

Sodium pnlmitafp^ in distilled water, 0*2 per cent. ; in bile-salt solu- 
tion, rO per cent. ; in Inle-salt yj/zw lecithin solution, 2*4 per cent. 

SfMlinm stearate, in distilled water, 0*1 per cent. ; in bile-salt solution, 
0*2 per cent. ; in bile-salt plus lecithin, 0*7 per cent. 

3. Calcium and Magnesium Soaps. — The usual stiitement that 
the " insoluble soaps " of calciimi and magnesium arc solulile in bile 
receives considerable modification when tested quantit^itively, for the 
experiment shows that these soaps are only very sparingly soluble in 
bile. Neither the mixed calcium or magnesium soaps derived from 
beef suet nor their constituent sidts, viz., the respective oleates, palmi- 
tates, or stearates, are at all solu])le in distilled water, that is to say, 
*he solubility in each case lies much below 0*1 per cent., which we 



On the Functions of the Bile as a Solvent, 73 

bave taken as the lowest practicable limit in making our determina- 
tions. The solubility of the mixed calcium or magnesium soaps in bile 
is difScult to accurately determine on accoimt of the undissolved resi- 
due of palmitate and stearate left behind. Wlien even as little as 
0*1 per cent, of either mixture is added to ox bile a residue is obtained. 
The magnesium soaps are somewhat more soluble than the calcium 
soaps, but in both cases the solubility is very low. In the case of the 
mixed calcium soaps, apparently none is taken up into the solution 
after 0*2 per cent, has beeu added ; and in the case of the mixed 
magnesiiun soaps the same result is attained after the addition of 
about 0'4 per cent. Similar results are obtained in the case of the 
mixed soaps with bile-salt solution alone, and with bile-salt plus 
iedthin. A bile-salt solution (5 per cent.) ceases to dissolve more 
when 0*1 per cent, of mixed calcium soaps has been added or 0*2 per 
cent, of mixed magnesium soaps ; and the figures are almost doubled 
when 1 per cent, of lecithin is dissolved in addition in the bile-salt solu- 
tion used. 

When the solubilities of the separated soaps in bile-salt, or in bile- 
isXtplus lecithin, solutions are tested, it is found that the solubilities 
are only considerable in the case of the oleates ; and here again it is 
seen that the magnesium salts are more soluble than the calcium salts. 

Calcium oleate^ in bile-salt solution, 0*2 per cent. ; in bile-salt plus 
iecithin solution, 1*4 per cent. 

Calcium palmitate, in bile-salt solution, less than 0*1 per cent. ; in 
hWe-BsAt plus lecithin solution, 0*9 per cent. 

CaJrium stearate, in bile-salt solution, less than 0*1 per cent. ; in bile 
viXtplns lecithin solution, 0*4 per cent. . 

Moffiicsium oleaUy in bile-salt solution, 3*2 per cent. ; in bile-salt plus 
lecithin, 8*2 per cent. 

Magnfmim pdlmUatey in bile-salt solution, 0*2 per cent. ; in bile-salt 
pins lecithin, 1*2 per cent. 

MafjiiCinmii stearate, in bile-salt solution, less than 0*1 per cent. ; in 
bile-salt plus lecithin solution, 1 *0 per cent. 

The physiological importance of the solubilities of the calcium and 
magnesium soaps in bile has, in our opinion, been much overrated. 
.\lthough the figures above given show that the solubilities of the 
mixed soaps of calcium or magnesium are very low, and hence that the 
usual statement that these bodies are soluble must be modified, a point 
of more physiological import is that the percentage of such soaps 
formed in the intestine during digestion of fat must be very small 
under normal condition, and hence their solution by the bile is of no 
great physiological moment. Such solubilities as are quoted above, 
low though they be, are in any case more than sufficient to account for 
the absorption of such minimal amoimts of calcium or magnesium soaps 
as may lie formed during fat digestion. 



74 Messi-s. !>. McK)rc and AV. H. TarkxT. 

4. Lkcithix. — The p<;)wev which aqueous solutions of hile-salts 
possess of taking up a hirge quantity of lecithin into rhor solution at 
iKxly temperature is very interesting from the point of view of the re- 
absorption of the bile-salt«, as is also the fact that in presence of 
lecithin the solvent power is greatly increased for other fatty sub- 
stances, such as the free fatty acids and soaps, as is shown by the fore- 
going figures. 

IMre lecithin is practically insoluble in water, the addition of as 
little as 0*1 per cent, causes an opalescence, and further additions give 
rise, as is well known, to a kind of emulsion. But when lecithin is 
added to a 5 per cent, solution of bile-salts,^ the appearances observed 
are quite different. 

The lecithin dissolves to a clear brown-coloured solution, and the 
amount taken up is siu*prising ; thus a 5 per cent, solution takes up no 
less than 7 per cent, of lecithin at a temperature of 37** C. On cool- 
ing, part of the lecithin is thro>m out of solution as a finely suspended 
precipitate or emulsion, which glistens with a silky lustre when the 
test-tube containing it is shaken so as to set the fluid in motion. At 
ordinary room temperatures of 15 to 20' C, a considenible amoimt of 
lecithin, 4 to 5 per cent., is, however, still retained in solution. 

The power of lecithin in increasing the solubilities of the fatty acids 
and soaps, explains in greiit pint why lower solubilities are obtained in 
experimenting with pure bile-salt solutions, than with bile. The 
lecithin naturally occurring in bile thus increases the solvent power of 
that fluid in the intestine for fatty acids and soaps. 

5. CiiOLESTEARix. — After the high solubility obtained for lecithin, 
we were much surprised at the excessively low solubility obtained for 
cholcstearin, and procee<led as above descrilnxl to make preparations of 
pimj cholcstearin from several different sources. The experimental 
residts obtained were however uniform ; in all cases it was found that 
while cholcstearin is apprecial)ly more soluble in bile-salt solutions than 
in water, in which it appears to l>e al>solutely insoluble, yet the degree 
of solubility is very low. Thus, in several experiments >nth ox bile, wo 
were miable to dissolve 0*1 per cent, of cholestearin additional, and as 
far as we could judge most siimples of bile are practically saturated 
with cholestearin. A 5 per cent, solution of bile-salts dissolves about 
0*1 ixjr cent, of cholestearin, and the amount is not very appreciably 
increiused by the simultaneous presence of lecithin ; at any rate, the 
amount dissolved b}' 5 per cent, of Inle-sjdts phi.< 1 per cent, of lecithin 
diK?s not exceed 0*15 per cent. 

This exceedingly low solubility of cholestearin in bile fiunishcs an 
interesting experimental explanation of a well-known clinical fact, 

* Tlie same results arc obtained when lecithin i!^ added to bile ; thus a sample 
of ox bile dissolred G per cent, at 36" C. Thi.'* shows that bilcTis noc nearly 
saturated with lecithin under normal conditions of its secretion. 



On the FuTidians of the Bile as a Solvent. 75 

viz., that gallstones so often consist of almost pure cholestearin. On 
account of the low solubility of cholestearin, the bile (the excretory 
jigent for this substance) must, even under normal conditions, be almost 
saturated with it. Hence anything which either diminishes the amount 
of bile-salts in circulation or increases the amount of cholestearin in the 
circulation, such, for example, as increased metabolic changes in the 
nervous tissues, may cause a supersaturation of the bile with cholestearin, 
and a deposition of that substance. Such a deposition would occur most 
commoidy in the gall bladder where the supersaturated bile is stored 
for a time, and where absorption of water and probably of bile-salts 
also occurs, lowering the solvent power of the contained bile. When 
precipitation from solution does take place, as is well known under 
such conditions, the deposition will occur most readily around any 
nidus of foreign material, such as an epithelial cell. 

In such conditions, it is obviously the supersaturation of the bile 
with cholestearin which is the primary predisposing factor to gallstone 
formation, and not the presence of the epithelial cell. When a stone is 
once started, like a crystal already formed in a solution, its surface is 
ik favourable situation for continued deposit, and so the stone continues 
to increase in size. The ringed appearance of the cross- section is probably 
due to alternations in the rapidity of growth, the bile being more satu- 
rated with cholestearin at some periods than at others. Lecithin and the 
other constituents of the bile, with the exception of the bile pigments, 
being very soluble are not represented in the composition of gallstones. 

CONX'LUSIOXS. 

1. Bile has a diuil function as a solvent : (a) it acts as a solvent for 
lecithin and cholestearin, and hence aids in the excretion of those 
otherwise insoluble bodies by the liver cells, and in their carriage to the 
intestine ; (b) it acts as a solvent in the intestine for both free fatty acids 
and soaps, conferring their entire solubility on the former, and largely 
increasing the solubility of the latter. 

2. These solvent properties of the bile are chiefly due to the bile 
salts ; but in the case of the fatty acids and soaps the amount dissolved 
is greatly increased by the simultaneous presence of lecithin. 

3. These solvent actions of the bile siilts explain the utility of the 
reabsorption of the bile-salts and their circidation through the liver, so 
that they may be used over and over again as solvent agents. In absorp- 
tion, the bile salts carry the soaps of fatty acids into the coliunnar cells ; 
in the liver, they arc a])Sorbed by the liver cells, carry the excretory 
lecithin and cholestearin with them, and are passed into the bile canali- 
culi holding these substances in solution ; in the bile, the lecithin and 
cholestearin are carried in solution to the intestine; and in the in- 
testine, the soaps and fatty acids aie dissolved and rendered capable of 



7() (hi tJie Ihnictlons of the Bile as a Solvent. 

]>eing taken in along with the bile-salts by the columnar cells, while 
the lecithin and cholestearin which are incapable of absorption are 
precipitated as the bile-salts are absorbed. 

4. Lecithin possesses a high solubility in the bile, and cholestearin a 
very low solubility. The low solubility of cholestearin furnishes an 
explanation of the fact that gallstones are composed almost entirely 
of this substance. 

5. The sodium soaps possess only a low solubility in water, the palmi- 
tate and stearate being practically insoluble; but the solubility is 
increased by the presence of bilensalts, and especially in the presence 
of lecithin ; further, the character of the solution is different in the two 
cases, being less colloidal when in bile-salt solution. 

6. Even in bile or bile-salt solution the calcium and magnesium soaps 
have a low solubility, but of the two the magnesium soaps are the more 
soluble. 

7. These results cast some light on the relative functions of the pan- 
creatic juice and bile in fat digestion and absorption. The enzyme of 
the pancreatic juice splits up the neutral fats, forming free fatty acids, 
which are largely converted into soaps by the alkali present ; while the 
l)ile gives solubility to the fatty acids and soaps so produced. Now it 
is well known that the fat-absorbing power is impaired but not com- 
pletely destroyed by the absence of either one secretion, but is 
practically lost when both secretions are absent. These facts can 
probably be best explained as follows: — {a) In the absence of the 
pancreatic ferment, since the bile has no action upon neutral 
fats, and these are insoluble, only that portion can be a1>sorbed 
which is free in the fat when ingested, or is set free in the stomach, 
or by bacterial action in the intestine. Since bacterial action is at 
a minimum in the small intestine, the fat in great part is not set 
free until the large intestine is reached, when the bile salts have all 
been reabsorbed, and hence cannot assist in solution. Accordingly, in 
the absence of the pancreatic secretion, a large percentage of the fat 
appears as fatty acids in the fieces. (U) In the absence of the bile, 
although the fat is decomposed high up in the intestine and converted 
into fatty acids and soaps, the absorption is slow because the solvent 
action of the bile is wanting, and hence only a fraction is absorbed, and 
the remainder passes on chiefly as fatty acid to be thrown out in the 
faeces. When both pancreatic secretion and bile are absent, in the 
first place only a small amoiuit is decomposed in the small intestine, 
and in the second place there is nothing to confer solubility on this 
small portion, with the result that absorption falls almost to zero. 



Application of the Kinetic Them^y of Gases. 77 



•' On the Application of the Kinetic Theory of Gases to the Electric, 
Magnetic, and Optical Properties of Diatomic Gases." By 
Gkobge W. Walker, B.A., A.RC.Sc, Fellow of Trinity 
College, Cambridge, Sir Isaac Newton Eesearch Student. 
Communicated by Professor EOcker, Sec. E.S. Eeceived 
January 23,— Bead February 14, 1901. 

(Abstract.) 

The aim of this paper is to apply the method of *' The Boltzmann- 
Maxwell Kinetic Theory of Gases" to the electric, magnetic, and 
optical properties of gases. For the sake of simplicity the molecule is 
supposed to consist of two atoms, so that the results apply to gases 
such as Hydrogen or Oxygen. Several of the results indicate, however, 
qualitatively what we might expect for more complex molecules. 

One of the atoms is supposed to have a positive electric charge and 
the other an equal negative charge, and the force in play between the 
two atoms is taken as the ordinary electrostatic force. 

It is contended that the molecules may be classified into three 
types — (1) that in which the two atoms rotate in contact ; (2) that in 
which the two atoms revolve in elliptic orbits about their C.G., but not 
in contact; (3) that in which the two atoms move in hyperbolic 
orbits for the short time during which they influence each other 
appreciably. They may thus be regarded as practically free. 

The first portion of the paper is concerned ^ath calculations respect- 
ing ^e relative proportions of these three sets ; and although a quite 
(x>mplete solution is not obtained, the results indicate certain important 
featui-es, and may prepare the way for a more complete investigation. 

It is next shown that such a system will exhibit magnetic properties, 
and the coefficient of magnetic smceptiUlity is calculated. The formula 
obtained shows a close agreement with Professor Quincke's experiments 
on this question. 

The system will also exhibit electrical properties. TJie dieledru- 
constant is calculated. The formula differs essentially from other 
theories of electric susceptibility, e.g,, Boltzmann's, in the important 
i^^pendence on temperature. A note at the end of the paper, giving some 
recent experimental results by Hon- Karl Baedecker, shows how 
closely the theory agrees with his experimental observations of the 
temperature effect. 

The electrical conductivity is calculated as depending on the number 
of free atoms present. Eeferencc is also made to a paper by the 
author, communicated to the Physical Society of London, in which it 
is shown how the formation of stride in a vacuimi tube may be 
accounted for. 



78 Proceedings and Lid of Papers read. 

The optical properties are next considered, and the amount of 
ref radian ])rodu€£d by free atams and nwleades calculated. The calcula- 
tions on the free atoms are of interest, inasmuch as it is shown that 
they acMeraie the vehcitii with which waves are transmitted. With 
regard to the molecules, it is shown that the optical control maif bf 
regarded rw due to Uj!^, the mean value of w- for the molecules, where m 
is the angular velocity of rotation of the two atoms about their 
common C.6. Dispersion is also accoimted for, and depends essenttall^ 
on tJie distribution law of velocities. The effects of radiation from the 
molecules are also considered in the course of the work. 

The rate of rotation of the plane of polarisation in a magndie field is also 
calculated, and the sign of the rotation shown to depend on which 
atom has the larger mass. If the masses are equal no rotation is pro- 
duced. The work borders in some ways with Professor W. Voigt's 
investigations. 

The formulae obtained are applied to the case of oxygen to obtain 
estimates of ejm^ and ejin-y^ e being the charge and nii and nis the masses 
of the two atoms. An estimate of co, and hence of 2ro, the sum of the 
radii of the two atoms, is also obtained. Th^i value of e/fni agrees dosd^ 
numericalhj with this ratio obtained from electivlt/tic considerations^ while the 
value of elm.2 agrees rhsehj with the mine obtained from considerations of tht 
Zeeman effect. 



Feh'uarg 21, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, followed hy 
The LORD LISTER, F.R.C.S., D.C.L., Vice-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. " An Attempt to Estimate the Vitality of Seeds by an Electrical 
Method." By Dr. A. D. Waller, F.R.S. 

II. ** On a New Manometer, and on the Law of the Pressure of Gases 
])etween 1*5 and 0*01 Millimetres of Mercury." By LoRD 
Rayleigh, F.R.S. 

III. " An Investigation of the Spectra of Flames resulting from 
Operations in the Openghearth and * Basic ' Bessemer Pro- 
cesses." By Professor W. N. IIartf.ey, F.R.S., and HrcH 
Ramage. 



An Attempt to Estiniatc the Vitality of Seeds. 79 

IV. " The Mineral Constituents of Dust and Soot from various Soiu^ces." 
By Professor W. N. Hartley, F.R.S., and Hugh Ramage. 

V. " Notes on the Spark Spectra of Silicon as rendered by Silicates." 
By Professor W. N. Hartley, F.RS. 

VI. " On the CJonductivity of Gases under the Becquerel Rays." By 
the Hon. R. J. Strutt, M.A., Fellow of Trinity College, Cam- 
bridge. Commimicated by Lord Rayleigh, F.R.S. 



" An Attempt to Estimate the Vitality of Seeds by an Electrical 
Method." By Augustus D. Waller, M.D., F.RS. Received 
January 28,— Read February 21, 1901. 

The present observations form part of an extensive series of experi- 
ments by which I am engaged in verifying whether or no "blaze 
currents "* may be utilised as a sign and measure of vitality. 

An inquiry of this scope necessitates superficial examination of 
many varieties of animal and vegetable matter, and the closer study 
of certain favourable test-cases. 

I have selected as such a test-case, the "vitality " of seeds, and have 
chosen for my purpose beans (Fhaseolus) which are anatomically con- 
venient and practically easy to obtain of known age. 

But before entering upon the results in this particular test-case, I 
think it advisable to preface those results by a brief indication of the 
principle involved in all such experiments. 

The method of investigation is similar to that adopted in the case of 
the frog's eyeball,* the complications of the principle and a tentative 
explanation of such complications is reserved for future discussion in 
a more comprehensive memoir. 

By " blaze current " (the term which I was led to adopt by the study 
of retinal effects) I mean to denote the galvanometrical token of an 
explosive change locally excited in li\ing matter. An unequivocal blaze 
current electrically excited is in the same direction as the exciting 
<jurrent, i,e,, it cannot be a polarisation counter-current. (An equivocal 
blaze current, in the contrary direction to the exciting ciUTcnt, i.e., not 
at first sight distinguishable from a polarisation counter-effect, also 
exists, but is not taken into consideration in this communication.) 

• A. D. W.-— "On the * Blaze Currents* of the Frog's Ejoball," * Roy. Soc 
Proc.,' vol. 67, p. 439, and * Phil. Trans.,' 1901. 

Although the theoretical explanation of these currents is not now in question, 
it may here be renuirlced that the unequirocal or homodrome blaze current is 
probably of local post-anodic origin (the previously anodic spot being now strongly 
elrctro-positiTe to the previously kathodic spot), while the equivocal or hetero- 
diome blaze current is probably of local post-kathodic origin (the previously 
luithodio spot being now strongly eloctro-jiositive to the previously anodic spof^. 



80 Dr. A. D. Waller. An Attempt to Esiimatc 

The presence of an unequivocal or homodrome blaze current is in 
my experience proof positive that the object under examination is 
alive. Absence of the effect is strong presumptive evidence that the 
object is " dead/' or rather not-living. It may be in that paradoxical 
state of immobility which we characterise as latent life, and which we 
may not characterise as the linng state, inasmuch as no sign of life 
is manifested, nor as dead, inasmuch as the living state can be resumed. 
An object in this dormant state exhibits no " blaze current " or other 
sign of life. And although it has capacity of life, and cannot therefore 
l>e classed in the category of " dead " things, it is not actually living, 
and must therefore logically be classed in the more extensive categoiy 
of not-liWng things. 

Limiting ourselves to the unequivocal blaze current as the criterion 
l>etween the living and not-living states, we may formulate the follow- 
ing practical rule for a summary interrogation of any given object : — 

If tlie afi^'-currents aroused by single induced currtnis of both direetions 
tiir in the mvw direction ^ the object investigated w alive. 

Practically, by reason of the fact that most objects of experiment 
nrc not physiologically homogeneous, this rule finds frequent applica- 
tion, inasmuch, as there is a favourable and an unfavourable direction 
f »f response, which occurs in the former direction, whether the excitation 
happen to l>e in the foi-mer or in the latter {e,g,^ electrical organs, eye- 
ball, skin, injured tissues animal and vegetable). 

In the case of objects that are physiologically homogeneous or nearly 
so, the after-currents to both directions of exciting current may be 
homodrome, i.e., of the nature of unequivocal blaze ciurrents. In such 
case it generally happens that the two opposite reactions are more or 
less unequal, by reason of imperfect physiological homogeneity of the 
mass of matter under investigation. It rarely happens that the 
physiological homogeneity is such that the two luiequivocal blaze 
currents are quite equal and opposite. 

So that the diagnosis of any suitable object as to its state of life or 
not-life rests upon the three following types of response : — 

1. Both after-currents aroused by single induction shocks (or by 
condenser discharges) of both directions are homodrome to the exciting 
currents. From which it is to be inferred that the object is li^-ing. 

2. Both after-currents are in the same direction. The object is living. 

3. Both after-currents are in the polarisjition direction. The object 
is not-linng. 

Direction of exciting current - + 



Direction of after-current (1) -^ 

(3) — 



the Vitality of SeeiU by an Elcctriml Method. 



81 



The three cases are indicated as above, and it shoidd be stated that 
in addition to the test of direction, electromotive force (which on my 
plan of investigation can always be approximately ascertained) serves^ 
to make the diagnosis easy in the great « majority of instances. The 
electromotive value in the case of an ordinary blaze current greatly 
exceeds that of an ordinary polarisation-current (^.y., the former on 
vigorous seeds may reach O'l volt, while on the same seeds the 
polarisation-ciurent similarly observed, was between 0*0005 and 
0*001 volt). It is only in the case of weak or moribund seeds that 
there is any room for imcertainty in the answer, by reason of a weak 
blaze current in conflict with the weak polarisation-current. But the 
vitality of such seeds, although we may be unable to assert that it has- 
fallen to the zero level, is insufficient for germination, and as tested in 
the incubator at 25° such seeds have to be registered as dead. 

The principal points of the preceding statements may be illustrated 
by the following experiment, which I give as being typical ; the 
expressions "positive" and "negative" signify that the currents 
respectively pass upwards from B to A, or downwards from A to B,. 
through the seed. 

Typical ExperiTnent, — A freshly shelled out and unbruised bean set 
up laterally* between unpolarisable electrodes gives — 

1. Blaze current in the positive direction in response to an induc- 



* I hare giTen this tjpical experiment only to represent main factH without 
detoils concerning diiferenoee aocording to strength of excitation, interval between 
Auoceaaiye excitations, temporary abolition by excessive excitation, recovery of 
capccity for reponse after injury, Ac, &o. These and other points will be dealt 
with in a more detailed and comprehensire account of the phenomena. It should^ 
however, be remarked at this stage that the lateral position of a bean, so tliat an 
exciting current traverses both cotyledons normally, is chosen as being the least 
asymmetrical and by reason of the situation of the embryo less liable to involve 
physiological inequality than a longitudinal disposition. The comparison of effects 
on the embryo proper and on the detached cotyledons shows that although all parts 
of the seed give the blaze effect, the latter is greater in the' embryo than in the 
cotyledons at the outset of germination, and that in an abortive germination it 
disappears from the embryo sooner than from the cotyledons ; e.^.— 



Cot. 1. 


Kadicle. 


Cot. 2. 


0-0060 

nil 
0-0060 


0-0625 
0-0180 
0-0170 


0020 
0015 
0040 



The plumule gave generally a smaller effect than the corresponding radicle. 
The peeled-off testa gave no blaze whatever, and was evidently dead; its 
polarisation counter-currents were relatively considerable. For these and other 
reasons I prefer to test the isolated radicle rather than the entire seed. 



82 Dr. A. D. Waller. An Attempt to Edimate 

Fig. 1. 







Fio. 2. 




Galvduionmter 



Excitor 



Object of 
ExAmlndLCion 



To a keyboard haying four plugs and plug-holes 1, 2, 3, 4 are connected — 

1. A compensator to balance any accidental current in circuit and to measure 

E.M.F. of reaction. 

2. An iuduction coil to supply the stimulus, preferably a single break shock, 

the make being cut out. 

3. The object under examination. 

4. A galvanometer. 

The procedure is as follows : — 

With 3 and 4 unplugged any current that may be present in the object is shown 
'by the galvanometer. Such current is balanced by manipulation of the com' 
pensator unplugged at 1. Wlicn exact compensation is obtained the galTanometer 
<^an be plugged and unplugged at 4 without any deflection from zero. 

With the galvanometer plugged at 4 a single induction shock is now sent 
through the object (with 1, 2, and 3 unplugged). Immediately afterwards the 
galvanometer is unplugged, and the deflection (caused by the after-oorrent) is 
noted. 

The K.M.F. causing it is approximately estimated by comparison with the 
deflection by a known E.M.F. from the compensator. 

tion shock in the positive direction ; and in the negative direction in 
response to an induction shock in the negative direction. 

2. The same bean after removal of a horizontal sHce from its under 






the Vitality of Seeds hy an Electrical Method 83 

surface B (giving therefore current of injury of positive direction) 
gives blaze currents in the negative direction in response to an induc- 
tion shock in the positive direction (= an equivocal blaze in the 
polarisation direction) and to an induction shock in the negative direc- 
tion (= an unequivocal blaze in the homodrome direction). If the 
1)ean is horizontally sliced at the upper siuiace A instead of at the 
lower surface B, the current of injury is negative and the blaze 
ciu-rents positive in response to both directions of excitation. 

3. A boiled bean gives no blaze currents in either direction but only 
small polarisation counter-currents, in the positive direction after a 
negative current and in the negative direction after a positive 
current. 

The next obvious point to be tested is the effect of anaesthetics 
upon the response. The results depend upon strength of excitation 
employed, and duration of ansesthetisation. Cceteris paribus, the strong 
effect of a strong stimulus is far more refractory to the action of an 
anaesthetic than the smaller effect of a weaker stimulus, and in the 
former case the suppression is apt to be incomplete, or when complete 
to be definitive. To obtain temporary suppression it is necessary to 
choose a sujficient but not too strong exciting ciurent, and to anaesthe- 
tise by ether rather than by chloroform. 

In a preceding paragraph it has been mentioned that a fresh vigorous 
seed gives a large blaze current, whereas a stale or moribund seed gives 
little or no response. The next step was obviously to compare similar 
seeds submitted to various enfeebling modifications, as well as different 
crops of similar seeds, the electrical tests being controlled by parallel 
germination tests. 

The first and most readily effected comparison is that between the 
reactions of fresh seeds and of the same seeds killed by boiling. The 
result of this comparison is unmistakable and invariable. Fresh seeds, 
giving unequivocal blaze currents with an E.M.F. of 0*01 to 0*10 volt, 
give no blaze currents whatever after they have been boiled, but only 
polarisation counter-current with an E.M.F. of 0*0005 to 0*0020 volt. 
The seeds upon which I have made this test have been legimiinous 
seeds, such as shelled beans and peas boiled in water, and the kernels 
of stoned fruits such as cherries, plums, and peaches boiled in their 
protected state.* 

* The reaction is abolished at a temperature considerably below that of boiling 
water ; e.g.^ at a temperature of between 40*^ and 50** of a warm moist chamber. 
Miss S. C. M. Sowton has carefully inyestigated this point and that relating to the 
effect of aniesthetics, by aid of photographic records, which are in fact indispens- 
able in connection with these two points. It is also abolished bj congelation 
(at — 3^ to —5^, which causes a sudden large electromotire effect at this point. 
On recorerj of normal temperature no blaze can bo obtained, and on recongelation 
there u no electromotiTe effect at the critical temperature. 



S4 Dr. A. D. Waller. An Attempt to Edinuite 

My attention at this early stage of the inquiry has been chiefly 
directed to the deterioration of seeds with age and to the comparison 
inter se of sets of seeds of certificated years by means of the germina- 
tion test and of the blaze test used quantitatively. 

[ selected beans as being of suitable bulk and readily obtainable, and 
I have to thank Messrs. Sutton for supplying me with many different 
samples of known dates. After a considerable number of trials upon 
entire seeds variously orientated between the electrodes, soaked in 
water of various temperatures for various periods, and upon the several 
isolated parts of seeds, I fixed upon the follo\viiig procedure as con- 
veniently yielding series of numerical results comparable inter se. 

The " dry " l)ean8 are first soaked in water for twelve hours in an 
incubator adjusted at 25"* C, then laid upon moist flannel and replaced 
in the incubator for examination during the next day. Each bean was 
then peeled and split, and the radicle was carefully broken off and placed 
l)ctween the clay pads of the electrodes (fig. 1) so that the uninjured 
4ipex was in contact with the upper electrode A, and the fractured 
base with the lower electrode B. With this position we have a 
^* positive " current of injury from B to A, and have to expect a " nega- 
tive blaze " current from A to B in response to excitation. In order 
that the response shall be " unequivocal," the exciting current is taken 
of negative direction. To ensure maximal effect a strong current is 
taken, viz., a break induction shock at 10,000 luiits of Berne coiL 
And inasmuch as a current of such strength repeated for a second time 
shortly after a first trial produces little or no effect, and even wh^ 
repeated after a considerable interval a much smaller effect than at its 
first application, it is necessary to take for the purpose of numerical 
comparison exclusively the values obtained at first trials. To this end 
it may be necessary to shunt the galvanometer to such an extent that 
the blaze effect to be expected from the first excitation shall give a 
<leflection within the scale ; a second trial when the first trial has given 
a deflection off scale, is of no value whatever. 

By adoption of imiform conditions on these lines, comparisons may 
profitiibly be made between different series of results. But at thk 
early stage of the inquiry, not knowing what conditions it might be 
advisable to select, I have' been forced to vary them in tentative direc- 
tions, by variation of strength of excitation,* of length of soakage, luid 

* To avoid exhaustion bj strong currents, and to obtain a regularlj repeated 
siTies of eifect«, I find that condenser discharges are more suitable than indue* 
lion shocks. Tlie discharge of 1 microfarad charged bj two Leclanche cells (a aboul 
10 ergs) usually gives a convenient normal effect upon which t^ inrestigate Um 
cil'ects of temperature variations, and of antcsthetic vapours. 

I also find it preferable to use the radicle some hours after it has been bit>ken d^ 
by which time its current of injury has subsided, and blaze currents are obtainaU* 
in both directions. 



the VitcdUy of Seeds by an Electrical MetJiod, 



85 



of interval between soakage and examination. These departures from 
strict uniformity, while affording necessary information, restrict legiti- 
mate comparisons to data within each particular table ; comparisons 
from table to table may not be safely made. 



Fig. 3. 






3 /O /3 SO 85 SC 



O-OI 


^..^ 1 
























- 
















C/<Jc 






/ 










4/ tA9 






/ 
















r 














/ 












CrdO 

<yo7 
VoU 
















1 













Photographic record of an unequivocal blaze current of the radicle of a bean 
(1900 crop). Excitation by a strong break induction shock in the A to B or 
uegatiye direction. Homodrome response of 0*075 volt. 



AVith regard to the germination tests, they have been carried out for 
the most part upon similar lots taken from the same parcels as those 
from which other seeds were taken to be electrically tested as described 
above. This latter required each seed to be broken up and rendered 
luifit for germination. I think that the parallel pair of tests made 
upon twin lots of different individual seeds is nearly as conclusive as if 
both tests had been made upon the same individual seeds — vule, e,g., 
Table I. Nevertheless, to meet the criticism that this proof is not 
inclusive, I have obtained three series of data in which the electrical 
and germination tests were carried out upon the same individual beans. 
In all three series I previously determined the coefficient of each intact 
seed by the blaze test ; the germination test was subsequently carried 
out in one series at Kew imder the supervision of Sir W. Thiselton- 
Dyer (Table VII) ; in a second series at Chelsea imder the supervision 
of Professor Farmer (Table VIII) ; and in the third series by myself 
in my own laboratory (Table IX). But I find it far less satiat'AeloT^ \,o 



86 



Dr. A. 1), Waller. A7h Attempt to Estimate 



make the electrical test iipon an entire seed with unknown local bruise& 
recei\ed during it« fresh state or in course of preparation, than upon a 
previously protected portion of the seed with an obvious injured end, 
as in the case of the radicle freshly exposed by separation of the cotyle- 
dons, and nipped off at its base immediately* before an observation is 
made. Moreover, in the former case the current-density is smaller, 
the blaze effects are relatively less considerable, and the polarisation 
counter-effects relatively more considerable. And, finally, irregularities 
due to irregular distribution of watert are more liable to occur in the 
comparatively large mass of an entire seed than in the comparatively 
small mass of its removed radicle. 



Table I. — Comparison between Eadicles of Bean Embryos of the years 
1860 and 1899. In each case the seeds were soaked in water at 
room temperature (15" to 18°) for 24 hours before experiment. 

N.B. — In these and all subsequent experiments the radicles were disposed as 
described in the text, with uninjured apex to electrode A and fractured base to 
electrode B (6g. 1). Excitation is by a single break induction shock of a Berne 
coil, fed by two Leclanche cells, 10,000 units, negatiyo direction from A to B. 
The blaze current is in the same (negative) direction, t.e., is unequivocal. 

The galvanometer was shuntod to such an extent that T^oth Tolt gave a deflec> 
tion of 4 cm. of scale. At this degree of sensitiveness polarisation currents are 
practically illegible. 



Seed. 


1860. 


Seed. 


1899. 


No. 1 

,, a 

„ 3 

„ 4 

., 5 

,. 6 

„ 7 

,, 8 

., 9 

.,10 














No. 11 

M 12 

„ 13 

„ 14 

„ 15 


-0 0750 
-0-0400 
-0 0700 
-0 0600 
-0 0350 
-0-0350 
-0 0100 
-0 0175 
-0 0200 
-0 0075 


» 16 

» 17 

» 18 

„ 19 

'' 20 


Average blaze. . ' 
Germination . . per cent. 


•• 


-0-03700 
100 per cent. 



* Or some hours previously {vide note on p. 84), although in such case the 
radicle has appeared to be more rapidly exhausted by repeated stimulation. 

t ficans soaked unequally (at the end of twenty-four hours) give blaze currents 
from more soaked to less soaked portions and not rice rtrsd, A bean that is left 
for several days in water becomes water-logged and finally decomposes. Such a 
'• drowned " bean will not germinate nor give any blaze whatever. A half- 
drowned bean gives blaze only towards the droT^Titd (or more soaked) Imlf. 



the Vitality of Seeds by an MectnccU Method. 



87 



Seed. 


1899 
(after three days Seed, 
in water). 


1899 

(after four weeks 

soaking in water, 

i.e., rotting). 


No. 21 

» 22 

.. 23 

„ 24 

„ 25 

f» 26 

» 27 

„ 28 

» 29 

,. 30 


-0-0300 No. 31 

-00150 . „ 32 

-0-0200 „ 83 

-00200 „ 84... 

-00250 ;. „ 35 

-00100 ! „ 36 

-0-0100 „ 87 

-00250 1 ,. 38 

-0 0176 „ 89 

-0-0200 „ 40 


oooooooooo 


Average 


-0-01925 ! 






Remarks. — The seeds of 1860 gave no blaze currents, nor any sign of germina- 
liion. All those of 1899 gare blaze currents and germinated rigorouslj. In eon- 
wquence of prolonged immersion under water, other tweeds of 1899 became water- 
logged, and finally gave no blaze current nor sign of germination. 

Four weeks is not a minimum time. I have found beans to be without excep- 
tion completely drowned at the end of 5 days' immersion in water at 25^ and this 
period has probably not been a minimum. The shortest time of soakage after which 
[ have observed the blaze has been one hour. 

Table II. — Comparison between Beans of the years 1895 to 1899. 
Forty-eight hours' soakage at room temperature. Averages of 10 
seeds of each year. Germination test not made. 



( 





1895. 


1896. 


1897. I 


1898. 


1899. 


Weight of 10 seeds— 
Before soaking . . . 
After soaking .... 


grammes. 
6-2 
13-9 


5-8 
7-6 


1 

6-2 1 
12-5 1 


3-3 
6-4 


4-8 
10-5 


Average blaze. . j 


0014 


0036 


0-0043 1 


0-0(»2 


0-0170 



Table III.— Do., do. 



Time of soakage not noted (1 36 hours). 
October 15. 



Average blaze 



0-0008 



0-0027 00031 0035 



0-0086 



Table IV. — Do., do., but a different series. 



Average blaze . . . . 



0-0030 



0-0028 i 0-0033 ! 0-0240 



0-0260 



%-'r\r T "VVTif 



ss 



Div A* D. Waller, An Attempt t& SdimaU 



Tjible V, — Another eeries o£ three years (dates not known with 

certainty). 



1896 F 



1897? 



18&0. 



[ Average of 10 obiervation*' — . 

On entire Bet-d** *0002» ' — 

On tlc^p&mt«d radic-left. . . . . { 0*(XK)?* '0028 

Germinalion value ......>.. i 55 per eeut. i 75 per cent. 



j 

0014 (iiTFfulsr} I 

0*005€ (rvgulu) I 

90 per cent. { 



Tabic VI, — Beans (radicleB only) of two years, 1896 and 1900. 



Average of 10 ob*eptatioiis» 
Germination Talue ,,».,,., 



]895. 
Soaked for 
S — '5 hours. 



1900. 
Soaked fcxr 
3^^& houn. 



0W16 


o^oiso 


irregular 






100 per cent. 


" weak '" 


^^sti^ng" 



1900. 
Boaked for I 
12 hautik 



0*0510t 
100 per ecnL 



TrableVJL — Twelve Iriiaet Beans of 1895, soaked in water at '24^ fet 

12 hours, then laid on wet flannel in iucuhator for a further 

13 hours at 24% measured electrically on December 17, and for- 
warded to Kew for intlependent test by germination. I have t* 
thank Sir W. Thisel ton- Dyer for the account of thuir siih^eqiteyt 
behaviour. 



Subaequent boliavioujr &t Kew. 



Bean Ho. 1 
it ' 

10 
11 
12 



libuij reactions. 



Bate of gf^mkinatiou. ; Condilioa, ' 



0^0050 
0-0025 
U'0175 
-0125 


^0100 
. 
0^0100 


0^0050 

o-oioo 

0100 



December 28 

Failed 
Bec«mbcr 22 
December 27 

Failed 
Dei'embi^r 22 

Failed 
Decembef 25 

Failed 
Deceiuber 31 
DeiTfmber 24 
December 24 



I 



Wea¥.t 

Strong, 
Modefitb 

Strong. 

Strong. 

Weak* 
Strong. 
Btrong. 



* The rei^poniei were small and irregularp and m the caae of the entiR ff«^ 
the aritlinietieal iiieau of the j^Hes uf 10 ta of wrong — I.e., of polaiuatioi^ 
direetiou. Tlie I'leetrical resistance of all the radielea wa* teated mod found tol« 
within the UmitB of 100,000 and 200,000 ohmi. 

t The average value abtained from 20 entire beans won *0040. 

Tlie maiimum value observed on Ihe radielea of 1900 wa» '1200, 

f Those marked weak are not likelj to get beyond tbe eotjledoa 



the Vitality of SeciU by an Electrical Method, 



89 



Table VIIL— Intact Beans of 1895 and of 1900, tested Electrically by 
Dr. Bullot, and subsequently forwarded to Professor Farmer at 
Chelsea for an independently Germination Test. 





1 


Electrical 


response. 




1895. 


Accidoutal ^ 
current. 

1 


Exc. +. 


Exc. -. 


Germination. 


Xo. 1 


-0-0018 


-0-0003 


+ 0-0017 


Xone. 


„ 2 


-0-0023 


-0-0012 


-0-0021 


.J 


„ 3 


-O-O0O4 


+ 0-0004 


+ 0003 


)i 


„ 4 


-0 0014 


-0-0002 


+ 0-0003 


9f 


„ 5 


-0 0077 i 


+ 0-0008 


+ 0022 


«> 


„ «• 


-0-0022 ' 


-0 0001 


+ 0002 


)t 


,. 7* 


-0 0030 


-0-0002 


-J-0 0002 


>» 


„ H 


+ 00009 


+ 0038 


-0 0045 


)« 


,. 9 


-0-0100 


+ 0011 


+ 0070 


)> 


,.10 


-0 0020 


+ 0005 


-0 0038 


>» 


1900. 










Xo. 11 


+ 0010 


+ 0125 


-0-0075 


Yes. 


„ 12* 


+ 0005 








No. 


,. 13 


-00120 


+ 0065 


+ 0020 


Yos. 


„ 14 


-0 0205 


+ 0013 


+ 0100 


If 


„ 15 


+ 0-0025 


-0 00-10 


-0 0125 


t) 


,> 16 


1 -0-0070 


-0 0010 


+ 0046 


Xo. 


„ 17 


-0 0105 


* 0-0060 


-»- 0-0024 


Yes. 


„ 18 


-0 0025 


+ 0056 


-0.0050 


No. 


„ 19 


-0-0067 


+ 0012 


+ 004^4 


Yes. 


. 20* 


i -00025 

1 


-0 0003 


+ 0-0003 


No. 



AVith reganl to the second series Professor Farmer remarks that he 
does not attach much value to it, since the seeds were kept cool at first 
and otherwise more might have germinated. Nos. 14 and 18, according 
to the blaze test, shoidd have germinated, but did not do so. A seed 
giving blaze may fail to germinate, but I have as yet met with only one 
case of a seed giving no blaze, and subsequently germinating (Xo. 4 of 
Table X). 



• Nos. 6, 7, 12, and 20 had been preTiously boiled. 



U^l 



90 



Dr. A. D. Waller. An Attemgt to EstiinaU 



Table IX.— Intact Beans of 1895 and of 1900 tested Electrically and 
subsequently by Germination Besults. 



1895. 



No 


.1 


» 


2 


» 


3 


»> 


4 


»» 


5 




6 




K 


I) 


/ 


)i 


8 


» 


9 


>» 


10 


No 


.1 


)) 


2 


J, 


3 


,^ 


4 




5 


J, 


6 


,, 


7 




8 


,, 


9 


,, 


10 



1900. 



Electrical response. 



Exc. 10,000 -r . 



Eic. 10,000-. 



G-ermiuatiou. 



-0-0009 


-0-0010 


None. 


+ 0-0002 


+ 0-0006 




-0 0004 


-0-0003 







+ 0010 




-O-O0O7 


-0-0002 




+ 0-0007 


+ 0-0015 







+ 0-0008 i 


M 


-0-0008 


-o-ooio 


„ 


-0-0006 


+ 0003 







+ 0-0014 


: 


+ 0-0054 


-0-0020 


1 
Ye». 


+ 0021 


-0-0030 




+ 0-0032 


-0-0022 


1 


+ 0Ot2 i 


-0-0015 


1 


+ 0025 ; 


-0-0010 




+ 0-0008 


-0-0042 


I 


-0-0C08 j 


+ 0-0004 1 


Ko. ' 


+ 0-0004 j 


-0 0006 , 


Ye*. 


+ 0165 i 


-0 0104 ' 




+ 0-0025 ; 

i 


-0-0(»15 1 

i 


}) 



In my hands and in those of Professor Farmer the germination (in 
earth) of this 1895 sample was nil. The electrical response was 
throughout small and irregular. A further test of genninatioD matte 
on moist flannel in the incubator at 25' gave 40 per cent, as the pro- 
portion of seeds exhibiting any sign of acti^^ty. 

The second series of this table gave a very striking and satisfacUXT 
residt. Of the ten seeds all but the seventh had given clear electrical 
signs. They were planted in two regular rows and left undisturbed in 
a greenhouse for one month. At the end of this time the box coxt 
tained two rows of nine vigorous plants with a gap opposite di« 
niunber 7. 



the Vitality of Seeds by an ElectiHoal Method, 



91 



Table X. — Beans of 1900 crop {Phamdm?) soaked in water for 
12 hours, then incubated for 12 hoiu^. Tested electrically 
( + Br. 10000) on January 28. Incubated on flannel and observed 
on January 31 and on February 4, when they were again tested 
electrically. 





January 28. 


January 31. 


February 4. 


Blaze. 




Blaze. 


Germin. 


Radicle. 




No.. 1 


> f 0-0050 volt. 


Yes 


Large 


+ 00124 


» 2 





No 


None 


-00002 


,, 3 


+ 0-0035 „ 


Yes 


Small 


-0-0023 


., 4 


-00002 „ 


No (App. Feb. 2) 
Ye8 


Mod. 


+ 00006 1 


M 5 


+ 00018 „ 


Mod. 


-00006 : 


„ 6 


> +0-0050 „ 


Yes 


I.Arge 


+ 00050 


,. 7 


-00005 „ 


No 


None 


-00002 


„ 8 


-0 


No 


None 





„ 9 


> + 00050 „ 


Yes 


Large 


> +00100 


„ 10 


> +0-0050 „ 


Yes 


Large 


+ 00080 



Conclusion. 

The physiological character of the bhize reaction is proved (1) by the 
influence of raised tempera tiu*e ; (2) by its general parallelism with 
germination tests ; (3) by the influence of lowered temperature ; (4) 
by the influence of anaesthetics ; (5) by the influence of strong electrical 
currents ; (6) by the absence of blaze and failure of germination in the 
case of water-logged seeds. In every instance a bean giving no blaze, 
gave subsequently no sign of germination. 

There has been throughout these first observations a general, but not 
faidtless, correspondence, as regards magnitude, between the blaze 
reaction and the germinative activity. The correspondence is such as 
to make good the principal fact that the blaze reaction is a sign of life, 
and that its magnitude is some measure of what we designate as 
" vitality." The defects of correspondence may have been due to irre- 
gidarities in the results of the blaze test, or of the germination test, 
or of both tests. As regards great differences of vitality, both tests 
are obviously and in every case concordant, both replying by an 
indubitable " yes " or " no " to the question whether there is blaze and 
germination. As regards the lower degrees and the smaller differences 
of vitality, the chances of disagreement between the two tests are 
obviously greater. As regards the electrical test, it is more diflScult to 
take the measure upon the entire seed than upon its isolated radicle. 
As regards the germination test, it is not always easy to ensure 
identical and optimum conditions. 

Fresh and vigorous seeds manifest a large blaze response (0*0500 volt 
or more), and germinate strongly. Older and less vigorous ae^da TCivw\v 



92 On n New Manometer and the Law of the Pressure of Oases. 

fest a smaller blaze (00100 volt or less), and a leas active germination. 
Still older seeds, incapal^le of germination under even the meet favourable 
conditions, manifest still smaller ])laze (00010 volt or less), and finally 
none at all, or the small counter-effect (hie to polarisation (O'OOOS voli 
more or less). 

The series of communications, of which the present communicatioi) 
is the 12th, is as follows : — 

1. ** On tlu- R<'tiiml Currcuts of tlu* Frog*j» Eye, l£xeited by Light and Excitrd 

Electrically," * Roy. Soc-. Proc.,' vol. 66, p. 327, March 29, 1900 ; * Phil. 
Trail!*..' p. 123, 1900. 

2. '' Action ^Icctroiiiotricc do la Sub8t«ncc Vcgotalc conskH^utiTe ^ TExcitatisii 

LuiiiincuHC," ' Compt-cs Eeuduii <lc la Sociotv de Biologic/ p. 342. 
March 31, 1900. 
'^. " The Electrical Effects of Light upon (Jreen Leaves," 'Koy. Soc. Prw.,* 
vol. 67, p. 129, June 14, 1900. 

4. " Four Ob'<crvatioin* concerning the Electrical Efft»ct» of Light upon Giveii 

Leaves." • Phys^iol. Soc. Pnw.,' June 30, 1900. 

5. '* Le Deniicr Signe dv A'ie,'* * ConiptcM Reiulus de rAcadcmie de» Sciences.' 

September 3, KKX). 
C, '* On the Excitability of Nerve : its la^t Sign of Life," * Proceedings of the 
Neurological Society,* October 25, 1900 ; " Brahi," p. 542. 

7. " The Eyeball as an Elect rical Organ," ' Physiol. Soc. Proc.,' November 10, 

1900. 

8. " On the ' Blaze CurrtMits* of the Frog's Eyeball," * Roy. Soc. Proc.,* toI.07, 

p. 439, December 6, 1900 ; * Phil. Trans.,' 1901. 

9. " The Frog'ti Skin as an Electrical Organ," * Physiol. Soc. Proc.,' Decembers. 

1900. 

10. *' Action filectromotricc des Fcuilles Vertes sous I'lufluence des Lumi(*re« 

Rouge, Bleuc et A'crte," * Compter Reiidus de la Sociv'tc de Biologie,' 
December 22, 19tX). 

11. " Le Premier Sigiie de Vie," * C'omptes Rcnilus de 1' A.eademie des Science*,' 

December 24. 1900. 



" On a New Manometer, and on the Ijiw of the Pressure of Gas*?:* 
between 1") and 001 Millimetres of Mercury." l>y LuRi» 
Eaylehjii, F.Ii.S. deceived eFanuary !"», — Read Febniaiy 21, 
1901. 

(Abstract.) 

llie new manometer, charged with mercury, is capable of meaBurin^jt 
small pressures to an accuracy of 1 2000 mm. of mercury. This may 
be compared with the ordinary manometei', read with the aid of a 
cathetometer, which is capable, according to Amagat, of an accuracy 
of 1/100 mm. at most. 

With this instrument the behavioui- of niti-ogen, hydrogen, and 



An Investigation of tlie Spectra of Bessemer Flames, 93 

oxygen gases between the pressures mentioned has been investigated. 
The results confirm the applicability of Boyle's law. In the case of 
oxygen nothing has been seen of the anomalies encountered by Bohr, 
especially in the neighbourhood of a pressure of 0*7 nmi. 



** An Investigation of the Spectra of Flames resulting from Opera- 
tions in the Open-hearth and * Basic ' Bessemer Processes." 
By W. K Haktley, F.E.S., Eoyal College of Science, Dublin, 
and Hugh Ramage, A.E.C.Sc.I., St. John's College, Cam- 
bridge. Eeceived November 15, 1900, — Read February 21, 
1901. 

(Abstract.) 

Three papers on "Flame Spectra," by one of the authors, were 
published in the 'Philosophical Transactions ' for 1894. Parts I and 
II, "Flame Spectra at High Temperatures," and Part III, "The 
Spectroscopic Phenomena and Thermochemistry of the Bessemer 
Process." The results in the last of these papers had reference to 
the phenomena observed in the flames of the "acid" Bessemer 
process ; the present paper deals mainly with an investigation of 
the Thomas-Gilchrist or " basic " process. 

The Cleveland district of Yorkshire was chosen as the principal 
centre; owing to the interest taken in the work by Mr. Arthur 
Cooper, Past President of the Iron and Steel Institute, and in con- 
sequence of the courtesy and attention shown us, the North Eastern 
Steel Company's works at Middlesbrough were selected. 

It was found necessary at the outset to have three observers at work 
simultaneously, and the authors were voluntarily and ably assisted by 
Mr. E. V. Clark, A.R.S.M. Photographs of the plant and the flames, 
at different periods of the blow, were seciured by means of a small 
Anschiitz camera and Goertz lens ; eye observations were made with 
a small direct-vision spectroscope ; photographs of spectra were taken 
with the spectrograph described in 'Philosophical Transactions,' A, 
vol. 185, p. 1047, and the times of the exposures, &c., were observed 
and recorded in a note-book. This work was not accomplished with- 
out some difficulty, which was occasioned by the large quantity of lime 
dust blown into the air. 

The spectroscopic results were quite different from those previously 
obtained, as the continuous spectrum was much stronger. Many 
lines and bands new to the Bessemer flame spectra have l^een observed 
in addition to the spectra of the common alkali metals, iron, and 
manganese. Thus nibidimn, caesium, calcium, copper, silver, and 
gallium have been identified. The crude iron, the ores, limestone^' 



94 Prof. W. N. Hartley and Mr. H. Eamage. 

lime, slags, fluo dust, and the finished steel have all been analysed, and 
their constituent elements have been traced all through the procen 
of manufacture. 

While no indication was obtained of the amount of phosphoruB in 
the metal during the process of 'M>lowing," some insight into the 
chemistry of the process has been obtained. The greatest interest, 
however, is attached to the knowledge it has given us of flame spectra 
luider variations of temperature, and of the ^vide distribution of many 
of the rarer elements in minute proportions in ores and common 
minerals.* 

Coitipmiaon, of Sjtedm from Open-Jieaiih and Cupola Funiacts. 

Early in 1895, by kind permission of Mr. F. W. Webb, the flame 
over the hearth of a Siemens' open hearth steel furnace in Crewe 
works was examined spectroscopically, but no lines of metals except 
sodium were detected. The continuous spectrum of the light emitted 
by the walls was very strong, and extended to wave-length ^70. 
Observations were also made at this time on the spectra of the flame 
Hl)ove the charge in a cupola. While the blast was turne<l on the 
tlame was bluish, and lines of sodium, lithium, and potassium were 
observed. When the blast was stopped, the flame became smaller and 
whiter, and the lines of the al)ove elements Ijecame stronger; the 
ends of the two strongest Iwmds of manganese were also seen. 

Ih'at'riptwn of iJu' " JJlmv'^ and " Onr Bhno^^ in the lladc BrASt'iner 

Pl'OCfs.^, 

The converter is first charged with about two tons of lime in lumps, 
and then with twelve tons of fluid "mixer metal," admixture of metal 
coming direct from the }»last furnace, and molten pig iron from the 
cupolas. The blast is turned on and the vessel rotated into a nearly 
vertical position. 

The " blow " may be divided into three stiiges. The first stage ends 
when the flame drops, indicating that the carbon lias been Inu'nt. The 
second stage ends when the vessel is turned down for a sample of 
metal to be taken out and the slag poured ott*. More lime is then 
added and the ])low is continued for a few seconds longer to complete 
the removal of the phosphorus; this foi'ms the third stage. The 
average duration of the first stage was twelve minutes and twenty 
seconds, and of the second stage, fiWQ and a half minutes. 

The blow began with the expulsion of a large quantity of lime 
dust, which hid everything from view for a minute or two and covered 

* *Roy. Soc. rroc.,' vol. OO, j)]). 35 r.nd 3'J3; 'Cliem. S<:c. Tpuiis./ 1897, pp. 533 



-rl n Inrestigaiian of the Spectra of Bessenwi* Flames, 95 

the instruments and observers. A fiame was visible at the mouth of 
the converter as soon as the cloud of dust had cleared away ; this had 
a yellow or yellowish-red colour. The flame grew rapidly in length 
nnd remain^ clear as in the '^ acid " process, until it dropped and the 
second stage began. In this stage the flame was very short, and a 
large quantity of fume was expelled from the vessel ; the flame grew 
longer and the quantity of fume increased as the " blow " proceeded. 

Twenty-six plates of spectra were photographed; some of these 
were very sharp and gave a complete record of substances present 
in the flame at intervals of one miimte throughout the blow. Care- 
ful measurements of the best spectra have been made, and the wave- 
lengths of the lines and bands recorded. The others, not measiu'ed in 
detail, have been compared with these, but no linas or bands occur in 
them which do not also occur in the best plates. A plate of spectra 
was usually taken by giving the same time of exposure to each 
spectnun of the series imtil the flame dropped ; two further exposures 
were then made on the flame of the over-blow. The spectra increase 
in intensity as the blow proceeds in the first stage, and this can only 
result from a corresponding increase in the temperatiu'e of the bath 
of metal and of the flame. 

Much detail was lost in many of the spectra, by the interference of 
the light reflected from a large quantity of white dust and smoke in 
the air in the neighbourhood of the converters. The converter nearest 
the observers was the only one of the four from which delicate detail 
was obtainable, and this was only secured by working in the evening 
when the sun was very low, or after it had set. 

Considerable difficulty was experienced in the identification of some 
of the lines and Imnds. This was due partly to the comparatively 
small dispersion in the less refrangible portion of the green and red rays, 
hy which lines and the sharp edges of bands were almost indistinguish- 
aUe on the strong continuous spectrum. In other cases, lines were 
present which had not been observed in flame spectra before, some due 
to uncommon elements, and others were relatively much stronger 
than a study of the oxyhydrogen flame and other spectra of the same 
metals led us to expect. 

(1.) Liio' .<i)0'tra ore not uh^fiod in ilw i^pfii-hrnrth fnrnarr. This 
i-^ attributed mainly to the fact that the atmosphere of the furnace 
i"? oxidising, and under these conditions, as Gouy has shown,* only 
tfwlium gives a spectrum approaching in intensity that which it gives 
in a reducing flame. The D lines were observed by eye observation, 
but did not appear on the photographs. 

* «Phil. Mag.,* vol. 2, 1877, p. 156. 



96 An Inresfiffation of the Sjwctra of Bessemer Flames. 

(2.) Th- ])hmomfn*i of thr " hi$ir " Btt^nif'r hhnv- differ awsuienfUv 
from thitsr- of ihf " dcid " prtH'esa, 

First, H flame is visible from the commencement of bloining, or as 
soon as the cloud of lime dust has dispei'sed. We eonehide that the 
immediate production of this flame is caused by carboiiaceous malt«r 
in the lining of the vessel, that its luminosity is due partly to the 
volatilisation of the alkalies, and to the incandescence of lime dii5t 
carried out by the blast. 

Secondly, volatilisation of metal occurs largely at an early perioii 
in the blow, and is due to the difference in composition of the 
metal blown, chiefly to the smaller quantity of silicon. There l« 
practically no distinct period when silicious slags are formed in the 
** hxaic " process, and metals are volatilise<l readily in the re<iucing 
atmosphere, rich in carbon monoxide. 

Thirdly, a very large amount of fume is fonned towanis the close of 
the second peiiod. This arises from the oxidation of metal and of 
phosphorus in the iron phosphide being productive of a high tempera- 
ture, but little or no car])<)n lemaining. The flame is comparatively 
short, and the metidlic vap>urs carried up are Inu-nt by the blast. 

Fourthly, the " over-blow " is characterised by a very |)owerfiii 
illumination from what appeals to be a brilliant yellow flame : a ileiise 
fume is pioduced at this time composed of oxidised meUillic vapouK, 
chiefly iron. These imrticles are undoubtedly of very minute dimen- 
sions, fis is proved by the fact that they scatter the light which fali'? 
on them, and the cloud casts a brown shadow, and, on a still day, 
ascends to a great height. The spectrum is continuous, but docs lu'i 
extend beyond wave-length 4000. This indicat<js that the source of 
light is at a comparatively low temperature, approaching that of a 
yellowish-white heat. We conclude, therefore, that the light emanates 
from a torrent of very small piiiticles, liquid or solid, at a yellowish- 
white heat. The " flame " can have but little reducing power at this 
stage, and this, togethei- with its low temperature, accounts for the 
very feeble lines of lithium, sodium, potassium, and manganese seeniu 
the ])hotographs, or by eye observations. 

Fifthly, the spectra of flames from the first stage of the ''Iwsic* 
process difl'er from those of the ** acid " process in several pjirticular*- 
The manganese bands arc relatively feeble, and lines of element^}, not 
usually associated with Bessemer metal, aie present. Both the 
charges of metal and of "basic" material contribute to these. Lithiiun, 
sodium, })otassium, rubidium, and caesium have Injen traced mainly to 
the lime ; manganese, copper, silver an<l galliimi to the metal. Other 
metals, such as vanadium and titanium, are not in evidence, liecaurt 
they do not yield flame spectra ; they, together with chromium, pa*? 
into the slag in an oxidised state. 

(.*3.) Diil'n'cmrs in tJu- inU'imtti if mfhil/ir lims. The intensity d 



Mineral Coiidit^terUs of Ihist and Soot from vainous Sotares, 97 

the lines of any metal varies with the amount of the metal in the 
charge, but in some eases variations of intensity occur among the , 
lines of one metal as observed in the spectra photographed at Crewe 
in 1893 ; especially is this the case with some lines in the \asil)le 
spectrum of iron. 

These variations are due to changes in temperature ; as the tempera- 
ture of the flame rises, some lines fade almost away, others ]>ecome 
stronger. The changes are more marked in the arc spectnim and still 
more in the spark spectnun of iron. 

Lines of potassium and the edges of manganese bands are shown to 
have l)een intensified by the proximity of iron lines in some cases, but 
this is doubtless a result of low dispersion. The two violet nibidium 
lines nearly coincide with two lines of iron.* 

A new line of ]fofassium mth vaiinbk infensifff. This line, wa^'e- 
length approximately 4642, varies in intensity within somewhat wide 
limits. In a given flame its brilliancy is increased by diminishing the 
luantity of metallic vapour in the flame : this does not appear to 
lepend altogether on the weakening of the continuous spectnim ; it is 
probably due, in part at least, to the increased freedom of motion 
permitted to the molecules of the metal. 



'The Mineral Constituents of Uust and Soot from various 
Sources." By W. N. Haktlfa', F.lt.S., Koyal Collej^^e of 
Science, Dublin, and Hucjh Kamage, A.K.C.So.L, St. John's 
Colle<;e, Cambridge. Ileceived November 20, 1900 — Keail 
February 21, 1901. 

Baron Nordenskjold has described three different kinds of dust 
rbich were collected by him.t Of two of these, one consisted of 
liatomaceae and another of a silicious and apparently felspathic sand : 
K)th were found on ice in the Arctic regions. The third variety was 
[uite diff'erent and appeared to be of cosmic origin. He observed that 
ome siind collected at the end of a five or six days* continuous fall 
ras mingled wnth a large quantity of sooty-looking particles, consist - 
ag of a material rich in carbon. It appeared to be similar to the 
nst which fell, with a shower of meteorites, at Hessle near Upsala 
1 the beginning of the year 1869. As in this particular instance it 
right Ixj supposed that the railways and houses of Stockholm had 
ontributed some of this matter to the atmosphere, and that the snow 
acl carried it down, he requested his brother, who then resided in a 
esert district of Finland, to give his attention to the subject, with 

• 'Boy. Dublin So(5. Proc./ toI. 8 (X.S.), Part VI. p. 705. 
t • Coraptes Rendu*/ vol. 78, p. 236. 



98 Prof. W. N. Hartley and Mr. H. Eamage. The Mineral 

the result that he collectetl a similar powder. The snow gathered in 
the latitude of 80' N. in an expedition to Spitzbergen, and that 
collected from floating ice in the Arctic regions and on the glaciers d 
Greenland, leaves, after it has melted, a greyish residue, which consists 
largely of diatomacese, l»ut mixed with these organisms there were 
also particles of a carbonaceous dust of considerable size, which oii 
anal3"si8 were found to cont^iin metallic iron, cobalt, and nickel, also 
silicon, carbon, and phosphorus. The origin of this mineral matter 
was at first doubtful. Two of its constituents, co1>alt and nickel, were 
believed to bo of very uncommon occurrence in terrestrial matter, 
while on the other hand they are elements invariably associated widi 
the metallic iron of meteorites, the nickel being more particularly in 
laige proportion. If we suppose that this dust is discharged from the 
mouth of a distant volcano, or that it may l>e sand carried up by a 
whirlwind, we have yet to explain the peculiarities in its composition 
which render it similar to that of meteorites. 

Xordenskjold arrived at the conclusion that it was meteoric matMr 
which had descended upon the earth in a shower similar to that whiek 
occurred near Upsala. By the facts which he had collected it appean 
tu have been proved that cosmic dust is falling imperceptibly and 
continually. It seems that this view is either generally not accepted, 
or that the facts are not conmionly known. 

Veiy little is i-eally known about the composition of atmospheiie 
dusi, notwith.standing that searching investigations were made by 
Pa^jteur and Angu?? Smith, aided by the microscope, and later by Liveing 
and Dewai- by the aid of the spectroscope. 

Professor OTleilly, M.K.I.A., supplied us with small quantities of i 
material concerning the natuie of which he was desirous of obtaining 
information. On insijection it appeared to ])e of an unusual chanicier 
for mere town (last, and accorrlingly we submitted it to a spectro- 
graphic analysis, and iletermined the princip«d metallic elements which 
enter into its composition. The following specimens in pirticular have 
l>uen exjimined with care : — 

(I.) Solid matter which fell in or with hail in a hail-storm ou 
Wednesday, April 14, 1?:>97, and was collected by Professor O'Reilly 
at a window facing the large open spice of Stephen's Green, at the 
Jioyal College of Science, Dublin. It contained iron, sodiiun, lead, 
co])per, silver, calcium, potassium, nickel, manganese a trace; gallium 
and cobalt gave doubtful indications. 

(II.) Solid matter from hail and sleet collected by Professor O'Keilly 
fi'om a window-sill of the Koyal College of Science, Dublin, during » 
veiy heavy showei*, fi'om 2.30 till 3 o'clock, in the afternoon of March 
28,'^189C.'* 

Total weight of the dust 0*1018 gramme, of which 0*08 gramme 
was burnt in the oxyhydrogen fiame. The colour of the dust was steA 



Constituents of Dust and Soot from various Sources, 99 

grey and it was magnetic. It contained iron, copper, and sodium, 
lead, calcium, potassium, manganese, nickel, silver, thallium a trace, 
gallium and rubidium a trace, doubtful. 

(in.) Pumice from Krakatoa eruption 1883; from Prof essor O'Reilly. 
By decomposing the silicate with ammonium fluoride and sulphuric 
acid, and precipitating the solution with ammonia, the following bases 
were separated : iron, copper, silver, sodium, nickel, potassium, rubi- 
dium, manganese, gallium, and indium a trace.^ 

The salt separated by filtration and evaporation of the filtrate 
contained sodium, potassium, calcium, copper, silver, strontium, nickel 
a trace, rubidium, and manganese. With the very notable exceptions 
of strontium, nickel, and cobalt we have found these constituents in 
ninety-seven irons, ores and associated minerals.! On the other hand, 
in the examination of six meteoric irons, we have foimd the same ele- 
ments invariably associated with nickel and cobalt, the last-named being 
always in much smaller proportion than the nickel. { Had it been 
possible to operate on larger quantities, we quite expect that cobalt 
would have been found in this dust, but the small amount of 8 centi- 
grams is insufficient for such a purpose, even in the case of most 
meteoric irons. It is rather a striking fact that in the dust No. 2 
there is a trace of thallium. This is rather suggestive of its being 
probably pyrites flue dust, a substance which might occur in hail or 
rain in a neighbourhood where sulphuric acid is manufactured. It 
might possibly come from an admixture of soot yielded by a coal con- 
taining thalliferous pyrites. 

There are three vitriol works within 2 or 3 miles of the College, 
but after taking all the facts into consideration, we are not able to 
admit this soiu*ce as a proba])le means of contamination, for as will 
be seen from analyses to be presented, there is one notable constituent 
we have foimd in flue dust which is absent from the samples I and 11^ 
namely, indium. 

In 1897, in order to push this inquiry somewhat further, dust was 
collected in porcelain dishes placed upon a grass plot in the garden of 
a residence just on the outskirts of Dublin§ during a period from 
the 15th November to the 15th December. A considerable fall of a 
carbonaceous-looking matter occurred on the 16th and I7th of No- 
vember ; some of the particles were 2 or 3 mm. in diameter, and had a 
rteel grey appearance rather like hard coke or graphite. These 
particles all sank in the rain-water which collected on the 17th or 
18th, while a large number of sooty particles floated ; as the dish 
became over-filled, the sooty matter was automatically washed away 

• * Trans. Chera. Soc.,* vol. 79, p. 61, 1901. 

t Nickel was found in twenty-three. * Trans. Cbem. Soc.,* vol. 71, p. 533, 1897. 

X * Sci. Proc. Dublin Soc.,' New Series, vol. 8. 

§ At the back of mv house and remote from any factory chimneya. — ^W. "55 . H. 



100 Prof. W. N. Hartley and Mr. H. Ramage. The Mineral 

and only the heavier particles remained. The contents of the dishei 
were poured into glass cylinders, and after the heavier particles had 
heeii deposited the water was removed by decantation. 

Subsequently it became interesting to ascertain what substances are 
to be fomid in ordinary soot and flue dust — dust from volcanic 
erui)tions, *^c. We have tabulated the results and arranged t<^ether 
those substances which w^e know to have the same origin. 

The specimens of soot required no preliminary treatment before 
being burnt, and the analysis of each is given in the tabular statement 
only, but the different kinds of volcanic dust and Hue dust were dissolved 
an(l the silica removed, after which the bases were separated into 
groups, and the spectra of these groups were photographed ; each 
spectrum receives a detailed description preceding the tabulated 
statement. 

Flm Dusf, 

Phift' .386. — Dust from the flue of Crewe g;wworks. May 28, 1899. 
The silica was removed from 1 gramme by treatment with amnKV 
nium fluoride. 

Spectrum 1 . — The insoluble residue contained — 
Ca, Sr, Na, PI), Fe, Cu, Ag, K. 
„ 2. — The precipitate yielded by sulphuretted hydrogen— 

Pb, Cu, Ag, Ca, Xa, Fe, K. 
„ .3. — Tlie ammonium hydrate precipitate— 

Fe, Ga, Cu, Ag, Pb, In, Ni trace, 

Ca, Na, K. 

„ 4. — The ammonium sulphide precipitate — 

Mn, Xa, K, Cu, Ag, Xi, Fe. 
„ 5. — The less soluble sulphates — 

Ca, Sr, Cu, Xa, K. 
„ 6. — ^Magnesia and the alkalies — 

Xa, K, Ca, Si*, Xi, Rb trace. 

Plak 388. Spectra 4 and 7. — Insoluble residue after treating the diist 
>yith hydrochloric acid — 

Fe, Ga, Xa, K, Ca, Cu, Ag, Xi, Mn. 

Phtie 347. — Flue dust from Cleveland iron furnaces. 
Spectrum 1. — Samuelson^s samples, Xo. 6 — 

Xa, K, Ca, Fe, Rb, Pb, Mn; 
traces of Cu, Ag, Xi, Ga, Tl. 



ConstUiicTits of Bust and Soot from vai*ioits Sources, 101 

Spectrum 2. — Flue dust from basic iron fiu'iiace. Samuelson's 
No. 9— 

Na, K, Ca, Fe, Rb, Pb, Mn ; 

traces of Cu, Ag, Ni, Tl, Ga, In, Cs, Sr. 

„ 3. — Flue dust, Gjers, Mills, and Co. — 

Na, K, Ca, Fe, Rb, Pb, Mn; 
traces of Cu, Ag, Ni, K, Ga, In. 
PM^ 354. 
Spectram 4. — Flue dust, Gjers, Mills, and Co. — 

Fe, Ca, Cu, Mn, Na, K, Pb, Rb; 

traces of Ni, Tl, Ag. 

PM^ 325. 1. — Flue dust from Nicholson's copper smelting works, 
Hunslet, Leeds — 

Na, Cu, Pb, Tl, Ag, In, Fe, K, 
rV, (7n, M. 

Phite 312. — Iron py/ites from coal — 

Fe, Cu, Tl, Pb, Ag, and possibly a trace of gallium. 

VolcAinic Dust. 

Specimens received from Professor J. P. O'Reilly. 

Pl'fifi 311. — Te Ariki, After complete solution of the substiince the 
heavy metals were precipitated with ammonia and the filtrate with 
ammonium oxalate, after which the solution containing magnesia 
and the alkalies was examined. 
SjHictnim 1. — The ammonia precipitate — 

Fe, Ca, Pb, Na, K trace, Ga trace, Cu trace. 
,, 2. — The ammonium oxalate precipitate — 

Ca,#j>r, Mn, traces of Na, K, Pb, Fe, and Ag. 

„ 3. — Magnesia and the alkalies — 

Na, K, MgO, Mn, Rb, Cu; 
Ni the merest trace. 

Tmiruntja, 
Ph'feSU. 

Spectrum 4. — The ammonia precipitate — 

The constituents are similar to No. 1. 
„ 5. — Ammonium oxalate precipitate. 

Similar to No. 2. 
„ 6. — Magnesia and the alkalies — 

Similar to No. 3. 



102 Prof. W. N. Hartley and Mr. H. Eainage. The Mineral 

Le Hiipe-O'TcTvii, 
Plate 312. 

Spectrum 1. — The ammonia precipitate — 

Similar to Nos. 1 and 4. 

„ 2. — The oxalates — 

Similar to Nos. 2 and 5, but the silver was not so 
strong. 

„ 3. — Magnesia and the alkalies — 

Similar to Nos. 3 and 6. 

It is necessary to explain that the symbol for magnesium and the 
alkaline earth metals refers generally to the oxides. With magnesjum, 
in fact, this is always so, since the bands of the oxide magnesia aloiie 
are visible. In the case of calcium, the blue line 4226 la photographed 
when only a small quantity is present, but the bands of calcium oxide 
are the chief feature of the spectrum when the base is in larger propor- 
tion. Where the symbol is printed in italics it indicates a trace of the 
substance, and where followed by a note of interrogation it is not quite 
certain if even a trace is present, as, for instance, where only one of tvro 
rubidium lines is seen, there being two iron lines occupying almost 
the same positions ; or where one of the gallium lines is barely visible* 
and the second is enveloped by manganese lines. The relative strength 
of the lines, as seen by comparing the different spectra, is, in some 
instances, indicated on the tabulated statement by suflSxes, the num- 
ber 1 indicating the weakest line and 10 the strongest. 

The difference in the numlxjr of the iron lines is a measure of the 
quantity of iron present as metal or otherwise, and a comparison of tb« 
strength of the lines also indicates the relative quantity of substance^ 
The results in many cases are quantitative, inasmuch as the same weigb^ 
of material was taken. 

On the Xoturr of Dust from t/w Clouds. 

The principal characteristic of dust which has fallen directly from 
the clouds or collected l)y hail, snow, sleet, or rain, is its regularity in 
composition — each specimen appeiirs to contain the same proportions of 
iron, nickel, calcium, copper, potassium, and sodium. The proportion 
of carbonaceous matter must be small, otherwise a diminution in the 
proportion of the metals present would render the metallic lines 
weaker. There is a very considerable difference between the dust from 
sleet, snow, and hail suddenly precipitated, the difference lieing in the 
proportion of lead, which, in the dust from sleet, is much larger than 
in the other specimens, though dust from hail and one quantity 
collected from rain contain more than is found in any other specimens 



Constituents of Dust and Sootfrmn various Sources, 103 



g 
I 



c 



KM 

o 

o 



o 



•pwai 



cu ;l. 






^ 

fM 



Ah 



^ J= JS 

^ Ch 9h 



*iimiiuoji{3 I 



-awKEi^iiv^ 



■;t*qoo 



l^iaiic 



*ii(iil 



'^tnijxi*iix 



-mnviiioaig 



^ ^ ^. ^ 



^ e c: t3 
^ ^ » IS 



S25 ^ »5 Ses 



5^ ^ j^ >% 



« 91 « til 

:&( ^ Ed N 



S) 4 & flf 9 
^ [kf f£| Ph ^ 



i; s 



^66^ 






^ ^ 



EC CG CO % 



S 



A 



s5 






B 
^ 



4 






C 6 6 e 



o o 



3 6 



to ^ bo 

^ :s s 



a 5 






Ui faC W M 

^ -^ -f| -*: 



ba c>^ ^ bc 

^ ^ ^ ^ 



'J O Lj u 



3 J3 A _^ ^ 

o a o O u 






Id 



14 w 



' uin ipog 



^ K k ?^ 



N M K 









M 

E9 

'k^ 



^ 
w 



u^ 



>% 






2 
IS 



-< :^ 



^ :^^ 



^ • • '^ S JS 

*» « S . 
2^2 2 



'3 



I 



. S-^S 



p p p « 






o 









e2 






7' 







I I s 



H ^ 5 



& 



:h 2 ^ < 

o ^ ^ 



VOL. LXV///. 



104 Prof. W. N. Hartley and Mr. H. Bamaga The Mkurd 



1 



& 



> 

s 



o 



a 
6 

o 

H 



•«!J. 



% 



•iuTijrap«3 



•oujz 



a 



•p«yi 



^-^ ^ ^" ^ 
p^ Oi P4 Pk 



P4 ^ 






Pk P4 



•uniiraojq3 



•dsaatiSaiij^ 



•4I«loo 



Id^oisr 



6 : : : 


: • 


:6 


"' ' 


n -» -» %a 

^ :^ ^ s 


e 


: li- 




: : : : 


: 


te : : 


rt « . — 


y* 


: :S 


s • 



•UOJJ 



;S4 



•inmnBqx 



^ ^ <r >r 
H- H ^ Bs 









5 



•ranrpui 






•uinni«0 
•oiTimiuiniy 


it 


^ 

o 


cv. 








as d 






: 


: 


• 


; 


: 




:< 






50 


: 


: 


i 






•75 






•uini.i|«j 


a" 


s 


d- 


6 


c5 


6 


.33 


^ 


1 


•ranisduSBj^ 


: 


: 


: 


• 


: 


: 


: : 







•■"-^ns 



A i 






•jaddoQ 



= 3 






(55 



: <"1 
J 

5 5 



•nmi8»3 




I 


• 


• I 


:o 


: 


1 

•uinipiqnji 


cv. 




cv. 




^s 


S ^ 



'Uini88«)0J^ 



•lunipos 



w w U^ w 



Ui M 



\4\A 



W i<! 



>?; 



9 dsT 08 
^ ^ ^ 



.8 .-S :-5 ^^ I ^:2 

g-^-^j < ^ *^ 

•Ho 

.»a S*^ -^ ^^ '^ 

8eo "^ ud CO 

>»-<' >Wi' «l*^ ^—^ 

QQ 




CansMuents of Dust and Soot from various Sources, 105 



I T-I 


• 


• 


• 


_S 




(5 


^ 
^ 


fi I 


■tiinttuojrH3 

1 


5 


i : 


'M9U«SaV|; 


s 


1 


:g 




1^ 

• 


1 


1 

* 


■ 
• 


nm^ 


1 


• 


4 




■p^^N 


s, 


j5 


^ 




; '"^-^i 


£ 


s 


& 


£ 


• 
• 


£ 


& 


& 


Tinijttmix 


i; 


g; 


e; 

^ 


^ 


! 


* 


» 


*ixtiiiptij 


: 


^ 


: 


* 


^ 



*nmii|V{) 



Q Q Q «S 

^ Cb ^ Cj 






o 



d 
C 



c 

■J 

1 

i 



*«injnTiiiTi^y 



•rani^uouig 



*mnpp3 



08 



<3 a 



6 



•mni99xiSvy[ 



'^Hm 



-j^ddoQ 



<titiiini0 



*tunrpT<jti'^ 



^amnn^aj 



'uintpog 



•^ ^ 






5 ^ a «s 



c 



pfl H rt pfl 



1^ M M t4 



(tt 41 a 4 
l£i ^ ki ^ 






-3 



E ? 

H 

5" 



"S *" s 



t •< 






9 



1^ 



CQ 



(5 5^ 



« o 



i 



_ o o 

W ^ bO 

s ^ s 



:^ bO be ^ tei 



W 3 a ES 3 

o» Q O O O 

^ 

a • ' " ■ 

to ' * ' " 



M M M H 



4 « <4 li 

Wi f^!i Sq s5 






I ^ 

O O O oS 

i 1 1 1 

:^ s a s 



1 ^ 



106 Prof. W. N. Hartley and Mr. H, Eamage. The Mineral 

with such an origin. The only meteorite which containB as much lead 
as this is the siderolite from Atacama. 



Of Volcanic Dust, 

If we examine the spectra of specimens of volcanic dust it is nodofr- 
able that the heavy metals are, without exception, in eomparatiTely 
small proportions — lead and iron, for example — while lime, magnegu, 
and the alkalies are the chief basic constituents. The spectra of the 
heavy metals, the alkaline earths, and the magnesia with the alhlw 
appear on separate photographs. 

Of Soot from differetit Chimn^ffn, 

The nature of soot from different sources is characterised by 4* 
small proportion of iron in most specimens and of metals precipitatoil 
as hydroxides ; its large proportion of lime and the greater variahili? 
in the proportions of its different constituents distinguishes it fw" 
other kinds of dust collected from the clouds or in the open air. 6 
was certainly unexpected when nickel, calcium, manganese, copper, «« 
silver were found to be constant constituents of soot from differe«i 
chimneys and flues. The proportions of Icjul, silver, and copper «• 
much larger in the soot from the assaN'ing furnace and the laundrj 
chimney. 

To illustrate the differences observable in dust and soot of vano« 
kinds, a list is appended of the wave-lengths of the iron lines obserwl 
in the spectra from soot obtained from the laundry, laboratory, kitcheii 
and bedroom chimneys. A second list gives the wave-lengths of ^ 
l>elonging to other elements and observed in other substances as well » 
dust and soot. 

It will be seen thac-, nere is an extraordinary difference betwed 
the kitchen and the laundry soot, which is probably caused by a higl* 
temperature and more complete combustion of the fuel in the \d0^ 
fire. 

Flue Dust. 

In flue dust from different soiu"ces the chief chanicteristics are tta 
presence of lead, silver, and copper in larger proportions than in otb* 
varieties of dust or of coal ashes which have also l>een exaffiiD*** 
Nickel and manganese also are in larger proportions. But the ^ 
striking feature is the quantity of nibidiiun, gallium, indium, ^ 
thallium in all samples examined. 

It is evident now that we can state with absolute certainty wheditf 
two kinds of dust have the same composition or in what constitoeflft 
they differ substantially. 

When dust is collected in the open air it is liable to become nus*' 



ConstUtierUs of Dust and Soot from variom Sotcrces, 
The Lines of Iron observed in diflferent kinds of Soot. 



107 



Laundry. 


Laboratx)ry. 


Kitchen. 


Bedroom. 




5893-0 










4404-9 










4383-7 


4383-7 








25-9 










08 










4289-8 










16-8 


4216 






The two rubid. 


02-1 








ium lines 


4144-0 


4144 






4215 -8 and 


32-2 








4202 -4 almost 


4063-7 








coincide with 


45-9 








two iron lines 


3930-41 
28-0/ 


3930-41 
28 OJ 




3930-4' 
28-0/ 


4216 -3 and 




4202-1. 


23-01 
20-4/ 


23 -0l 
20-4/ 




23-01 
20-4/ 








06-6 


06-6 




06-6 




3899 91 
95-8/ 


3899 -91 
95-8/ 




3899-91 
96-8/ 








86-41 
75 ^j 


86-41 
78-7/ 


3886-4 


86-41 
78-7/ 




Eztremelj 
feeble 




72-6 


72-6 






65-6 










60 01 


60-01 
56-5/ 


3860-0 


3860 -0\ 
66-6/ 




56-5/ 


Very feeble 




50-1 


501 








40-5 


40-6 








34-3 


34-3 








r26-0l 
- 24-5/ 


•26-01 
• 24-5/ 




f 3826-0'! 
\ 24-5 




3824 -5 




20-5 


.20-5 


Barely yisible 


20-5, 




15-9 


15-9 








13-1 


13 1 








379y6\ 
98-6 ' 


3799-6 








98-6 








95 1 










88-0 


88-0 








49-6 
45-7/ 


49-61 
45-7/ 


8749-61 
45-7/ 


3749-61 
46-7/ 






35 O' 
33 -4 J 


350 
33 -4 f 


35 
33-4. 


35 01 
33-4/ 






27-7 


27-7 








22-61 
20-0/ 


22-61 

20-0/ 


3722-6 
20-0/ 


3722-61 
20-0/ 






09-3 


09-3 


The six last 


09-3 




05-7 


05-7 


lines are 


05-7 




3687-6 


3687-6 


very feeble 


3687-6 




80-0 


80-0 








77-8 


77-8 




3677 -8 




47-9 


47-9 








31-6 


31-6 








18-9 


18-9 








3585-61 
81-3/ 


3586 -5 1 
81-3 ' 














70-2 


70-2 









108 Mhural CwistUumta ofDtLst aiid Sootfronx various Sources. 

Wave-lengths of other Lines than Iron in Spectra from various lands 
of Dust and Soot, and in Meteorites. 





Sodium. 


Calcium. 




Chromium. 


D 


5896 -n Mean 
5890 -2/ 5893 


4226-9 Aline. 


4289-9] 




lines. 




4274-6 


A triplet. 




8303 -1 1 Mean 
3302 -5/ 3302 -8 


Calcium Oxide. 


4254-4 






^.l^Qft 't\ "> 


•3605-8' 








0090 V 
to 

54S5 -0 


A strong 


8593-7 


• A triplec. 




Potassium. 


band. 


8578-8. 






6805-0 


6253-0' 










4047-4 \ Mean 
4044 -0/4045 -7 


to 


► A band. 




Manganese. 




6116-0 




4034-6 


Lines which often ap- 




Liihiutn. 
4602-3 


6075-0' 

to about 

5985-0^ 


A weaker 
band. 


4033-2 
4031-0, 


► pear like one broad 
line. 




8232 -7 


Magnesium Oxide. 


3273 -6 


Copper. 




Casi'um. 


3929 O] A band, 


3247-0 






4557 


to V strong, 
3856-0 J diffuse. 




Silver. 




Subidium. 


3834 -Oi A band, 
to about • strong, 


3383-5 
3282 1 






4215 -7 


8805-0 J diffuse. 






4202 -4 


Stronlium. 




yickel. 




Thallium, 


4607-0 

Lead. 


3618-5 


The lines observed are 




5349 -6 
3775-6 


3609 -8 
3571 -2 
3461 


near the positions of 
such as are here indi- 
cated, and are proH. 




Gallium. 


4057-6 


3438-0 


ably identical with 




3682 -9 




them. There is also a 




4172-2 


3639 -2 




line 3525, the only one 




4033-0 






obserred in Cleveland 
pig iron. It docs not 




Indium. 






appear in these ana- 




4511 






lyses. 




4102 






1 



Some of the lines were measured with a micrometer and the wave-lengths deduced 
from a curve on an enlarged scale drawn from Rowland's measurement* of iron 
lines in the solar spectrum. 



with other dust and soot, and we cannot be certain whether it comes 
from only one Bource or not, but soot, as a rule, can be separated 
by washing it away from the heavier matter. The occiurence of nickel 
in soot and flue dust was certainly unexpected. It is probably 
disseminated in extremely minute traces in coal, and its concentration 
in soot is owing to the conditions in a coal fire being favourable 
to the formation of nickel tetra-carbonyl and its subsequent de- 
composition 



On the Spark Spectrum of Silicon as rendered by SUicates, 109 

Conclusions, 

(1.) The presence of nickel, as shown by the examination of soot, is 
not positive evidence that the dust from the clouds comes from other 
than a terrestrial source. 

(2) The dust which fell on the 16th and 17th of Novemljer, 1897, 
with its regularity in composition and its similarity to meteorites, 
being magnetic, also its comparative freedom from extraneous matter, 
exhibits properties which are quite in favour of its cosmic origin. 
Moreover, its composition is totally unlike that of volcanic dust and 
flue dust from various chemical and metallurgical works. This dust for 
the most part fell on a perfectly calm fine night, and there was no rain 
for twenty-four hours or more afterwards. 

We beg to draw attention once more to the very wide distribution 
of gallium in minute proportions ; it occurs in all aluminous minerals, 
flue dust of very different kinds, soot and atmospheric dust, also in a 
great variety of iron ores. Bauxite contains it in larger proportion 
than any other mineral, but the quantity even in this substance is very 
small. We have hopes of finding it concentrated in some mineral, as 
thallium, caesium, germanium, and indium are. Indium and thallium, 
the other members of the same group of elements, are found in blende 
and pyrites, and accordingly we might expect gallium to occur in a 
concentrated state in a sulphide, arsenide, or similar compound. 
Judging, however, from its analogy with aluminium, there does not 
aeem to be much probability of this. 



'' Notes on the Spark Spectrum of Silicon as rendered by Sili- 
cates." By W. N. Hartley, lMi.S. Keceived November 19, 
1900— Read February 21, 1901. 

The interesting account by Mr. Lunt* of his identification of three 
lines of silicon, corresponding with three imknowii lines in the spectra 
of certain fixed stars, contains the following remarks : — 

*' It is a curious fact that Hartley and Adeney, and Eder and 
Yalenta, who alone give us any extended list of lines due to silicon, 
appear not to have examined the spectrum of this element in the 
region of the three rays here considered. Their published wave- 
lengths show only lines in the extreme ultra-violet, and the majority 
of them are quite outside the region which can lie examined by the 
McClean star spectroscope." 

There is an inaccuracy hero, and a similar mistake as to author- 
ship occurs in the paper of Eder and Valenta. Silicon was not one of 
the sixteen elements whose spark spectra were investigated by Hartley 
• • Roy. Soc. Proc./ toU 66, p. 44. 



1 10 Prof. W. N. Hartley. Notes an the Spark 

and Adeney,* because it was found to be practically a non-conductor 
of electricity, and no uninterrupted stream of sparks could be obtained 
from it. A prior publication,t " On Line Spectra of Boron and Silicon," 
by me, gives descriptions and wave-lengths of lines characteristic of 
these elements which were observed in solutions of borates and 
silicates.} 

Having some of the spectra photographed in 1883, I find upon 
examination of the plates that they were closely investigated at that 
time. They show no trace of any line of silicon less refrangible than 
2881-0 (Angstrom's unit). 

There is a line at the less refrangible extremity of the spectrum 
which, to judge from its position, is yellow or yellowish-green in colour ; 
but it certainly does not ])elong to silicon, because solutions of a 
silicate, and of hydrofluosilicic acid containing 1 per cent., O'l per 
cent., 0*01 per cent., and 0*001 per cent, of silicon, show this line 
to be stronger in the spectrum given by 0*01 per cent, than in any 
other of the photographs. It has every appearance of and no doubt 
is the well-known pair of sodium lines with a mean wave-length of 
5893. A concentrated solution of sodium silicate gave no stronger 
indication of this line, and only a feeble representation of the strongest 
sodium line 3301. This may be accounted for by the remarkable fact 
referred to in the original paper, that the lines of the metal in l)orates 
and silicates seem to be suppressed when the spectra of boron and 
silicon appear with greatest intensity, but if the quantity of the 
borate or silicate in the solution is diminished, the sodium lines gain 
in strength. 

There is, however, a line near a very strong air line seen in the 
spectnun of a 1 per cent, solution. It continues to increase in length 
and intensity in other spectra as the proportion of silica diminishes ; 
otherwise it would not be noticeable because it is extremely short, 
feeble, and enveloped in air lines when photographed from a 1 per 
cent, solution. A solution equivalent to 0*001 per cent, of silicon 
yields a spectrum in which this line is about one-fourth of the length 
of the air lines, and of the seven carbon lines in other parts of the 
spectrum. 

It is in fact the least refrangible carbon line from the graphite 
electrodes 4266*3 (Hartley and Adeney), and is visible and of normal 
strength and length on photograph No. 10 in the 'Journal of the 
Chemical Society,' vol. 41, p. 90, 1882. It is one of those lines which 
is occasionally absent from the carl>on spectrum, and it is somewhat 

• * Phil. Trans.,' 1884, Part 1, p. 63. 

t ♦ Roy. Soc. Proc.,' 1883, vol. 35, p. 301. 

X For a list of these linos, see also Watts's ' Index of Spectra/ p. 127, 1889. In 
Appendix E, p. 21 of the Index, the same list of lines is headed H. and A., which is 
erroneous. 



Spedruiii of Silicon (is rendered hy Silicah'^ 



111 



lengthened when the electrodes are wet.* It is doubtless a carboii line, 
for Deslandrest gives its wave-length as 4267 (Rowland's unit), and 
he used carbon purified in Moissan's electric furnace. The least 
refrangible of the silicon lines on my plates is at wave-length 2881*0, 
and it corresponds with a line in the arc spectrum 2881-1 (Liveiiig 
and Dewar). 

There is a group of air lines t 4446*02, 4432*58, 4425*90, 4415*51, 
and 4413*60, then come 4628*95 and 4674*2, but there is no trace of 
any silicon lines between 4573 and 4553 where Mr. Limt found three. 

Mr. Lunt used a powerfully disruptive discharge, and that apparently 
18 sufficient to account for the difference in the spectrum which he 
obtained. I have always employed very simple apparatus, but it 
happens that when investigating the coefficient of extinction of the 
various rays of silicon a second series of experiments was made with 
a more powerful coil and jar. It was found that when all the lines 
had become very short, and the weaker lines had nearly disappeared, 
they could be reproduced to a great extent from the same solution by 
increasing the capacity of the Leyden jar or condenser, but as only 
axtremely dilute solutions of silicates were used, the lines obtained by 
Mr. Liuit from the solid silicates did not appear. 

I give here the normal length of the six lines in the characteristic 



>Silicon Lines. 

A. Strength of solution, or per cent, of silicon. 

B. Length of tlic lines in hundredths of nn inch. 



Description of lines. 



Strongest but one of the 

group 

A weaker line 

Strongest and longest . . . . 

Tlie weal^est lines of the 
group 

An isolated line weak and 
thin 



Tery strong line 2?8l '5 



Wave- 
lengths. 
(Rowland's 
unit.) 



2506*8 
2514 
2515-9 
2518 -9 
2523 -9 
2528 '6 

2631 -8 




A, 01. .A, 001. 
B. ! B. 



9 
8 
10 
7 
7 
7 

Bartly 

visibie 

9 



• • Phil. Trans.,' 1884, Part I, p. 49. 

t < Comptes Rendus,' 1895, toI. 120, p. 1259. 

X These waye-lengths are copied from the original numbers written upon the 
l6-xiicli enlargements of the spectra referred to as being published in the ' Journal 
d the Chemical Society.* The values are according to Angstrom's unit, and are 
ioubtless not so accurate as numbers more recently determined. 



112 Mr. F. C. Penrose. Some Additwiial 

group as they are seen when a 1 per cent, sohition and graphite 
electrodes are used, and of two isolated lines which are less refrangible; 
with them are compared the lines photographed from other more 
dilute solutions. The sodium line X 3301 appears as a long line in 
the 1 per cent, solution and becomes shorter as the quantity of sub- 
stance is reduced. 

Observations were carried as far as a solution containing OOOOOOl 
per cent, of silicon, the two strongest linos being still -idsible, but at 
the photographs of these more dilute solutions have been damaged by 
being kept so long a time in the atmosphere of the chemical laboratorj, 
they are not now availalile for similar measurements. 

As the sodium lines are suppressed when the silicon lines are strongs 
the cwo carl)oii lines are also reduced very much in length and strengtk 
This is very easily obser^'ed on iiccount of the close proximity of (he 
silicon lines, the wave-lengths of the two carl)on lines being 2508*7 
and 25 11 -6 (Hartley and Adeuey). In the more dilute solution, then 
lines are observed to be lengthened until they become of the normil 
dimensions of 20/lOOths of an inch. It thus appears more than probabk 
that the suppi-ession of the sodium does not result from any ehemicil 
action within the spirk discharge, such as might l)e supposed to occur 
if the sodium were dissociated from the compound, and being in 
contact with a silicate were to liberate silicon, or to combine with silicon 
directly, and in presence of water give rise to the formation of silicon 
hydride. 

The suppression of much of the sodium spectrum, and the shorten- 
ing and weaken irJ|j of the carbon lines, is more likely to be a purelf 
physical phenomenon than the result of any chemical reaction in 
the spark. 



" Some Additional Kotos on the Orientation of Greek TempIeSr 
being the Uesult of a 'Journey to (Ireece and Sicily in April 
and May, 1900." By F. C. Pknuose, M.A., F.E.S. Received 
January 17, — Kead February 14, 1901. 

(Abstract.) 

The paj)er contains notes on two examples from Greece and four 
from Sicily— of these, three are of the nature of ampKfication and 
correction, and three are fresh cases. 

(1.) To the second head belongs a nide and archaic shrine in thi 
Isle of Delos ; not improbably the most ancient existing example of • 
religious structure on Greek soil. It cxhi})its the usual stellar con- 
nection with its orientation and an approximate date conformable wiA 
its remote antiquity (1530 B.C.). 



Notes on the Orientation of Greek Temples. 113 

(2.) Some further observations on the Temple of Apollo, at Delphi, 
of which the recent complete clearance of the site admitted of measiu'c- 
ment with greater exactness than before. 

(3.) At Syracuse I found that the architecture of the temple which 
has been erroneously attributed to Diana,* was of a character much 
too archaic for the date assigned to it in that paper, which had been 
derived from the orientation of the axis ; but that when taken from 
the northern limit of the eastern opening the date woidd be quite 
consistent both with architecture and the history of the town. 

(4.) This led to a re- examination of the other Syracusan examples 
and an error was discovered, altering the orientation of the temple 
attributed to Minerva, and its derived date, from 815 to 550 B.C., to 
its great advantage in every respect. 

(5.) The most interesting example, however, is from another 
Sicilian temple lately unearthed at Selinus. Of this temple I foimd 
the orientation of the eastern axis to be 30" 22' north amplitude, which 
at once suggests a solar temple arranged for the summer solstice, 
which for a level site and for the date in question, shoidd be 30"^ 35'» 
But the temple's site is near the bottom of a valley; and the sun 
would have to gain an altitude of rather more than two and a half 
degrees Ijefore it could shine into the temple ; and then the amplitude 
required would be 28'' 17'. Thus apart from what may be derived 
from the plan of the temple itself, the orientation theory would seem 
to show to a disadvantage. At the same time the peculiarities of the 
plan of the temple would be difficult to explain without the orientation 
theory. 

Presumably the angle upon which the lines of the temple were set 
out was taken from data obtained on some platform which had a level 
horizon, and the building was considerably advanced before the actual 
solstice came round and showed the error that had been made. 

To meet the difficulty a nam was constructed within the flank walls, 
hut hugging the northern one ; so that the first beam of sunrise 
coming through the centre of the eastern aperture, at the local ampli- 
tude of + 28'' 17' E., might shine in centrally upon the statue of the 
<leity : and for this a pedestal was provided a little northwards of the 
centre of the niche which had been previously formed for it. We may 
notice also that the angle of the Propylaea is so placed as to keep 
exactly clear of the point of sunrise (see figure, next page). 

(6.) An argiunent is drawn from the orientation of the foundations of 
a small temple lately discovered, adjoining the famous theatre at 
Taormina, that the theatre itself was that of the city of Naxos, which 
occupied the sea-coast at about 800 feet immediately below it ; and 
not the work of the much later town of Tauromenium, from which 
Taormina derives its name. 

• * Phil. Trans./ A, rol. 190, 1897, p. 39. 



"4 AddUional Mtts 



'''''<=0--^iatio. Of Greek Tcnpie,, 
Pio. 1. 




^^k *«ov„ad Tern J 



Proceedings, 115 



Fcbruarij 28, 1901. 

Mr. W. H. M. CHRISTIE, Vice-President, Astronomer Royal, in the- 

Chair. 

The Secretary reported that on Saturday, February 23, the Presi- 
dent, accompanied by the Treasurer, the Senior Secretary, the Foreign 
Secretary, Lord Lister, Lord Kelvin, and Sir Joseph Hooker, Past 
Presidents, and Mr. Christie, Vice-President, had proceeded to St. 
James's Palace, and, being admitted to the presence of the Throne, 
had the honour of presenting to His Gracious Majesty an Address of 
Condolence and of Homage, and that His Majesty had made a gracious 
reply. 

The Address and Royal Reply are as follows : — 



To THE King's Most Exceli.kxt Majesty. 

Ty llumhk Address oj the President^ Coundly and FdUnvs of the lloiml 
Society of Loruhn for Promotiufj Natural Knowledge, 

Most (jracious Sovereign, 

We, Your Majesty's most dutiful and loyal subjects, the President, 
Council, and Fellows of thu Royal Society of London for Promoting 
Natural Knowledge, humbly beg leave to offer our deepest and most 
heartfelt sympathy with Your Majesty in the great sonow which has 
befallen You in the death of Yoiu- beloved Mother, our late Sovereign 
Lady the Queen. Your Majesty's loss is our loss also : a loss not only 
to ourselves, not only to all Yoiu* Majesty's subjects throughout the 
Empire, but to the whole world. During Yoiu* beloved Mother's wise 
and }>eneficent reign, under Her thoughtful fostering care, that natural 
knowledge which the Society was founded by one of Your ancestors 
to promote has been promoted to an extent, and in ways, never known 
before ; and we feel sure that not in our time only, but in the years 
to come, to the story of the advance of Science in the past century 
will be most closely linked the memory of the goodness, the wisdom, 
the peerless worth of the august and beloved Lady, whose death has 
now plunged us into the deepest grief. 

^^^lile thus uttering words of sorrow, we ask leave. Sire, at the same 
time, to lay at Your Majesty's feet our unfeigned and heartfelt con- 
gratulation upon Your Majesty's accession to the Throne of Your 
ancestors, to reign over a people to whom, happily, Yoiu* Majesty is no 



116 List of Papers read. 

stranger, but who have, by many experiences, learnt to recognise Your 
great worth, and have been led to the sure hope, that, under Your 
gracious rule, the Nation will continue to hold the proud position which 
it has gained under the guidance of Your beloved Mother. 

That Your Majesty's reign may be long, happy, and glorious, and 
that You may ever rule in the hearts as well as over the persons of a 
loving, dutiful, and grateful people, is the earnest wish and ardent 
prayer of 

Your Majesty's loyal and dutiful Subjects, 

The President, Council, and Felix)ws 

OF THE Royal Society of London. 

His Majesty's Gracious Reply. 

" I am much gratified by the warm expression of your loyalty and 
affection, of your profound sympathy with our present grief, and of 
your loving appreciation of the goodness and great qualities of my 
dearly l>eloved mother. 

" I thank you for your dutiful good wishes, and I share your hope 
that my reign also may be blessed by a continuous growth of my people 
in enlightenment, refinement, and power for good. The intellectual 
attainments and energies which your Society so conspicuously repre- 
sents are among the most precious possessions of the nation as aids in 
securing those high ends, and I remember with gratification the close 
connection of the Society with its Royal Founder and my other prede- 
cessors on this Throne, and the fact that I am a Fellow, as was also 
my dear Father. 

"You may feel assured of my constant interest in and protection of 
your work, and in token of my goodwill I shall be pleased to inscribe 
niv name .as Patron in the Charter Book." 



A List of the Presents received was laid on the table, and thanks 
ordered for them. 

The following Papers were read : — 

I. " The New Star in Perseus. — Preliminary Note." By Sir 
Norman Lockyer, K.C.B., F.R.S. 
II. "On the Structure and AflRnities of Fossil Plants from the 
Palaeozoic Rocks. IV. — The Seed-like Fructification of Leptdo- 
carpouy a Genus of Lycopodiaceous Cones from the Carboniferous 
Formation." By Dr. D. H. Scott, F.R.S. 
III. " A Preliminary Account of the Development of the Free-swim- 
ming Nauplius of Leptodon hi/aUna (Lillj.)." By Dr. E. 
Warren. 



Structure and Affinities of Fossil Plants from Palaozov: Rocks. 117 

IV. "On the Kesult of Chilling Copper-Tin Alloys." By C. T. 

Heycock, F.R.S., and F. H. Neville, F.R.S. 
V. " On the Theory of Consistence of Logical Class-frequencies, and 
its Geometrical Representation." By G. Udxy Yule. 



" On the Structure and AflBnities of Fossil Plants from the 
Palaeozoic Rocks. IV. The Seed-like Fructification of Lcpido- 
carpon, a Genus of Lycopodiaceous Cones from the Carbon- 
iferous Formation." By D. H. Scott, M.A., Ph.D., F.R.S., 
Hon. Keeper of the Jodrell Laboratory, Royal Gardens, Kew. 
Received February 19, — Read February 28, 1901. 

(Abstract.) 

A short account of the new genus Lepidocai-pon has been given in a 
note communicated to the Royal Society last August* ; the present 
paper contains a full, illustrated description of the fossils in question, 
together with a discussion of their morphology and affinities. 

The strobilus of Lepuiocarpon Lonutxi, the Coal-measiu*e species, is, in 
its earlier condition, in all respects that of a Lepidostrohus, of the 
tjrpe of L, Oldhamius, 

In each megasporangium, however, a single megaspore or embryo- 
sac alone came to perfection, filling almost the whole sporangial 
cavity, but accompanied by the remains of iu abortive sister-cells. 
An integument ultimately grew up from the sporophyll, completely 
enclosing the megasporangium, and leaving only a narrow slit-like 
opening, or micropyle, along the top. As shown in specially favour- 
able specimens, both of Lepidocaipoii Loinaxi, and of L, fFildianumy 
the more ancient Burntisland form, the functional megaspore became 
filled by a large-celled prothallus, resembling that of the recent Isoeie.s 
or Sela^iielln, The whole body, consisting of the sporophyll, bearing 
the integumented megasporangium and its contents, became detached 
from the strobilus, and in this isolated condition is identical with the 
** seed " described by Williamson under the name of Cardiorarpon 
nnomalum, which, however, proves to be totally distinct from the 
Cordaitean seed so named by Carruthera. 

The seed-like organs of LepidomrjHm are regarded by the author as 
presenting close analogies with true seeds, but as differing too widely 
from the seeds of any known Spermophyta to afford any proof of 
affinity. The case appears rather to be one of parallel or convergent 
development, and not to indicate any genetic connection between the 
Lycopods and the Gymnosperms, or other Phanerogams. 

• ** Note on the Occurrence of a Seed.like Fructification in certain Faleeozoic 
Lyoopods," * Eoy. Soc. Proc.,' toI. 67, p. 306. 



1 1 8 Tlieorif of ConsiMence of Logical Class-freqitomeSy dr. 

" On the Theory of Consistence of Logical Class- frequencies 
and its Geometrical Representation.*' By G. Udny Yulk, 
formerly Assistant Professor of Applied Mathematics in 
University College, London. Communicated by Professor 
K. Pearson, F.R.S. Received February 9, — Read February 
28, 1901. 

(Abstract.) 

The memoir deals with the theory of the conditions to which a series 
of logical class-frequencies is subject if the scries is to be self-consistent ; 
!>., if the class-frequencies are to be such as might l>e observed within 
one and the same logical universe. 

The theory has been dealt with to a limited extent by De Morgan, 
in his * Formal Logic* (" On the Numerically Definite Syllogism ") and 
by Boole, in the * Laws of Thought ' (in the chapter entitled " Of 
Statistical Conditions "). 

In the present memoir the first section deals with the theory of 
consistence, by a simple method, up to class-frequencies in ^ve attri- 
butes, and a general formula is then obtained, giving the conditions 
for any case. In the second part of the paper some illustrations are 
given of the geometrical representations of the conditions obtained in 
Part I. 

In the case of three second-order frequencies (AB). (AC), and (BC), 
the complete conditions of consistence may be represented by a tetra- 
hedron with its edges truncated. The first-order frequencies are treated 
as constant, (AB), (AC), (BC) as co-ordinates, and the limits to (BC), 
for example, are given by the points in which the line drawn through 
the point (AB) (AC) parallel to the (BC)-axis cuts the surface. The 
general form of the surface depends on the value of the firsi-oitler 
frequencies. If 

(A)/(xO = (B)/(u) = (C)/(u) = i 

(u) being the total frequency, the edges are not truncated and the 
** congnience-surface " l)ecomes a simple equilateral tetrahedron. The 
limits given to (BC) in terms of (AB) and (AC) in this case are shown 
to correspond to the limits to the correlation coefficient r^z in terms of 
ri2 and rys in the case of normal correlation. The congruence-surface 
shows very clearly the nature of the approximation towards the 
syllogism, as conditions of the "mriversal" type (all A's are B, or 
no A's are B) are approached. One or two illustrations are also given 
of congruence-surfaces for third-order frequencies, the first- and second- 
order frequencies })eing })Oth treated as constants. 

In the third part of the paper some numerical examples, and sketches 
of congnience-surfaces for actual cases, are given, in further illustration 
of the theory. 



jThe New Star in Perseus. 119 



" The New Star in Perseus. — Preliminary Note." By Sir Norman 
LocKYER, K.C.B., F.E.S. Keceived and Read February 28, 
1901. 

Dr. Copeland was kind enough to inform mo by telegram on the 
afternoon of February 22, of the discovery by Dr. Anderson of a new 
sUir in the Milky Way in Perseus on the early morning of that day. 
It was stated that its position was RA. 3*> 24" 25'' and Declination 
+ 43' 34', its magnitude 2*7, and colour of a bluish-white. Later in 
the evening this information was corroborated by another telegram 
from the " Centralstelle " at Kiel. 

Owing to cloudy weather, no photographs could be obtained at 
Kensington until the evening of the 25th. Momentary glimpses of 
the star on the evening of the 22nd, between the hours of 6 and 
7.30 P.M., indicated that the Nova had considerably brightened since 
the time of its discovery, as it was estimated as a little brighter than a 
1st magnitude star; no satisfactory observations of the spectrum could 
l>e made. Another glimpse on the early morning (1.30 a.m.) of Monday 
(25th) showed that the star was still of about the Ist magnitude. 

Professor Pickering repoi-ts that the Nova was dimmer than an 
11th magnitude star on February 19. On the 23rd it was as bright as 
Capella. The star, therefore, was then at least 10,000 times brighter 
than it was four days previously, and ranks as the brightest new stai 
recorded since that which appeared in the year 1604. 

Since the 25th the brightness has diminished slightly, and on the 
evening of the 27th was estimated between the 1st and 2nd magnitude 
(1-7). If this reduction of brilliancy continues at the same rate, the 
new star will evidently be shorter lived than those to which it h^is 
most closely approximat^ed in luminous intensity at the maximum, and 
less time will l)e available for studying the spectral changes which may 
be anticipated. I may state that Tycho's Nova (1572) was visible for 
nearly li years, and Kepler's (1604) for about the same period. 

It is interesting to note that the star was described by Dr. Anderson 
lis being of a bluish- white colour at the time of discovery. Since it 
has diminished in ])rightness this has changed, and on the night of 
February 27, a reddish tinge was observed. 

The sky on Monday evening was by no means free from clouds, 
but ten very satisfactory photographs were secured with the three 
instruments in regular use for stellar spectra. Edwards's isochromatic 
plates were used, as it was considered desirable to secure a record of 
the green part of the spectrum. 

Although there has not been time for a complete discussion of these 
photographs, it may be stated that the spectrum contains nimierous 
dark lines, several of which arc associated with bright bands on the 

VOL. LXVlll. V. 



120 



Sir Norman Lockyer. 



less refrangible side. Further, the spectrum, as a wbole, g: 
resembles that of Nova Aurigae. 



<< CQ 




One of the chief fe.iUires of the pi incipul bright lines is their 
width, amounting to 30 tenth inetres, and each is accompanied by 
line of considerable bieadth on its more refrangible side. A comj 
Kl^cctrum of y Orionis, photographed alongside that of the Nova < 



Tlie New Star in Perseus. 121 

of the plates, indicates that the middle portions of the bright lines are 
not far from their normal positions ; those of the dark ones, however, 
are displaced by some 15 tenth-metres towards the violet, thus indi- 
cating a differential movement of something like 700 miles a second. 

Movements more rapid and disturbances more violent than those 
observed in Nova Aurigse are therefore indicated ; both by the greater 
displacement of the dark lines relatively to those that are bright and 
the greater breadth of the bright and dark lines. 

The comparison of spectra shows us that we are dealing with two 
swarms, one of which, the less dense, gives us broad bright lines and is 
almost at rest with reference to the line of sight ; the denser swarm, 
indicated by the dark lines, is in most rapid movement in the line of 
sight towards the earth. 

An interesting feature of the spectrum is the presence of fine dark 
lines down the middle of each of the bright lines of hydrogen and 
calcium ; these are most probably reversals, and if this be so, they will 
l>e of great service for accurate determination of the wave-lengths of 
the other bright lines. The dark hydrogen line Hy, and perhaps Ufi 
and H5, are also possibly reversed. 

Eye observations showed among the chief lines a group of four in 
the green; one probably H/?, the others near XX 492, 501, and 517 ; a 
bright line at or near D, and a brilliant red line probably correspond- 
ing to Ha. Each of these was accompanied by a dark broad line on 
its more refrangible side. Other lines of less brightness were observed 
lK)th in the green and red. 

It at first seemed probable that two of the bright lines in the green 
(AX 492 and 501) might be due to asterium, while that in the orange 
was perhaps the helium line Ds. Subsequent investigation, however, 
suggested as an alternative origin that these lines might be the 
enhanced lines of iron at X 4924*1 and 5018*6, which are very nearly 
in the same positions as the asterium lines. This view was tested by 
inquiring whether other prominent enhanced lines of iron so strongly 
visible in the spectrum of a Cygni were present. 

A comparison with the spectrum of this star photographed with the 
same instruments suggested that many lines l>etween F and h in the 
Nova probably correspond with lines in a Cygni. Certainty could not 
lie arrived at in consequence of the great breadth of the lines in the 
Nova. 

Hence, as the Nova bore some resemblance to both Nova Auriga* and 
a Cygni, a reference was suggested to the lines recorded in the spectrum 
of Nova Auriga? which were observed when the light of that star was 
on the wane, and when the lines were thinned enough to be easily mea- 
surable. I may also add that these observations were made ])ofore the 
work on enhanced lines was undertaken. 

The importance of this reference was strengthened by the cou^iidera- 



122 Sir Normau I-ockyer. 

tioii thiit with such a tremendous outburst wo should oxpjct the original 
invisible swarm to have been (very rapidly) advanced to a considerable 
condensation at the locus of impact, and therefore to resemble some 
" star " which had (slowly) arrived at a position pretty high up on the 
ascending temperature curve in the ordinary course of evolution on the 
meteoritic hypothesis. 

A comparison of the bright lines recorded by Campbell* and Vogelt 
in the spectnim of Nova Aurigse with the strongest lines of a Cygni — 
a very detailed record of the spectrum of which star has been 
recently compiled here — shows that there is a close agreement 
between the two sets of lines. These strong a Cygni lines are almost 
without exception the representatives of " enhanced " lines of some of 
the metals, chiefly Fe, Ti, Cr, Ni, Ca, Sr, and Sc. If we exclude the 
lines of hydrogen from those which were recorded in the spectrum of 
Nova Aiu-igaj, there remain forty-four lines for comparison. Thirty of 
these, or about 70 per cent., agree approximately in position with either 
strong isolated lines or groups of lines in the spectrum of a Cygni. 

It may be assumed that, taking into consideration the broad nature 
of the Nova lines, if there l)e any genuine connection between them and 
the lines of a Cygni, any close groups of separately distinguishable 
lines in the latter spectrum would be thrown together in the Nova 
spectrum, and appear as broad bands. A good instance of this appears 
in CampbelFs list. He records a band extending from AA. 4534 to 
4501. In the spectrum of a Cygni there is a strong line at each of the 
positions given, and between them there occurs a strong quartet of 
lines. The former are well enhanced lines of titanium, and the latter 
of iron. It seems extremely likel}^ therefore, that the six lines thrown 
together produce the apparently continuous ])and observed by 
Campbell. 

If the stage of a Cygni has really been reached, the following con- 
siderations come in : — 

. In the orderly condensation of swarms, according to the meteoritic 
hypothesis, the curlier stages are — 

t Cvniitti i Dark lines, corresponding chiefly with 

I "^ " " * I the enhanced lines of rarious metals. 
= i rol'iri^n f Bark lines, comprising both arc and 

1 I ' ' L enhanced lines of various metals. 

p" f Dark lines, chiefly corresponding lo 

S I Aldebariun < those which appear in the arc spectra 

1^ I L of various metals. 

^ r Mi\ed bright and dark flutings and dark 

^ I Antarian < lines. Bright lines of hydrogen in 

<i L those stars which are variable. 

Nebula Bright lines. 

• * Ast.-Phys. Jour.,* vol. xi, p. 807, 1892. 
t * Ast.-Pbys. Jour.,* vol. xii, p. 912, 1893. 



The New Star in Persem. 123 

In the case of new stars, after the maximum of luminosity has been 
reached, however high they ascend, short of the apex of the tem- 
perature ciu-ve, this order must be reversed, and hence we should 
expect to find the spectrum varying in accordance with the foregoing 
sequence, but in the reverse order. 

In Nova Coronse (1866), according to the observations of Sir William 
Huggins and Dr. Miller, the absorption spectrum was very similar to 
that of a Ononis, which is a star of the Antarian group, so that the 
temperature attained was relatively low ; this indeed is demonstrated 
by the fact that at present it shines faintly as an Antarian star, and 
doubtless did so before the collision. The collision, therefore, probably 
did not take Nova Coronae very much above its initial stage of tem- 
perature, and when the disturbance was over it simply reverted to its 
old conditions. 

The spectrum of Nova Cygni (1876) was not photographed, and as 
special attention was given by most observers to the bright lines, 
there is no satisfactory record of the absorption spectrum. 

This now appears as a nebula, and doubtless it was a nebula to begin 
with, as Nova Coronse was a star to begin with. 

In Nova Aurigae (1892), as we have seen, the comparison with 
CL Cygni indicates that the Cygnian (a higher) stage was reached, 
and in the final stages its spectrum corresponded with that of the 
planetary nebulae, that is, a stage lower than that reached by Nova 
Ck>ronae. The intermediate stages, however, were not observed, 
i possibly because the star was never very brilliant, and partly because 
i ^f the difficulty of observing closely grouped lines, such as occur in 
I ttie Polarian and Aldebarian stages when they are rendered broad by 
I «U.oh disturbances as those which were obviously present in the Nova. 

The observed maximum magnitude in the case of a new star will 

f ^"^"idently depend upon the distance and size of the colliding masses, as 

! ^^ell as upon the temperature produced by the collision. It is not 

I ^^Xiiarkable, therefore, that there is no apparent relation between the 

I ^^eatest brightness and the temperature indicated by the spectra. 

r -^ova Coronae, with its relatively low temperature, shone for a time as 

^ ^ 2nd magnitude star, while Nova Aurigae, with a much higher tern- 

* l^i^ture, scarcely surpassed a star of the 5th magnitude. 

i^ I now return to Nova Persei. If the idea that in the present Nova 

j^/^e swarm which gives the dark line spectrum resembles a Cygni be 

t'^^nfirmed ; as its temperature is reduced we may expect it to pass 

:^^^^icces8ively through some or all of the stages of temperature ropre- 

;^^nted by stars of the Polarian, Aldebarian, and Antarian groups, 

^Jihanced lines being first replaced by arc lines, and then by flutings. 

- XWiether it remains at one of these stages or undergoes a further back- 

'Vardation into a nebula will be a point of the highest interest. 

If, like Nova Aurigae, the present Nova should end as a nebula, it 
t VOL. LXVni. li 



V 



124 



Proceedings and List of Candidaies. 



will furnish a most convincing proof of the fundamental metallic nature 
of nebulae. 

In conclusion, I wish to express my thanks to Dr. W. J. S. Lockyer 
and Mr. F. E. Baxandall, of the Solar Physics Observatory, and to 
Mr. A. Fowler, of the fioyal College of Science, who have greatly 
assisted me in preparing the present note, and who, with the addition 
of Mr. Butler, of the Solar Physics Observatory, secured the excellent 
set of photographs and eye observations on the night of the 26th, from 
which the new knowledge has been derived. 

The preparation of the slides I owe to Sapper J. P. Wilkie. 



March 7, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., 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 Candidates for election 
into the Society were read as follows : — 



Adeney, Walter Ernest, D.Sc. 
Alcock, Alfred William, Major, 

LM.S. 
Allen, Alfred Henry, F.C.S. 
Ardagh, Sir John, Major-General, 

R.E. 
Ballance, Charles Alfred, F.R.C.S. 
Binnie, Sir Alexander Richardson, 

M.I.C.E. 
Bourne, Gilbert C, M.A. 
Bovey, Professor Henry T., M.A. 
Boyce, Professor Rubert. 
Bridge, Professor Thomas William, 

M.A. 
Brown, Adrian John, F.C.S. 
Brown, John. 

Bruce, John Mitchell, M.D. 
Budge, Ernest A. Wallis, D.Litt. 
Callaway, Charles, D.Sc. 
Cardew, Philip, Major, R.E. 
Chattaway, Frederick Daniel, M.A. 



Clowes, Frank, D.Sc. 

Copeman, Sydney Monckton, M.D. 

Corfield, Professor William Henry, 
M.D. 

Crookshank, Professor Edgar 
March, M.B. 

Darwin, Horace, M.A. 

Davison, Charles, D.Sc. 

Dendy, Professor Arthur, D.Sc. 

Dixon, Professor Alfred Cardew, 
M.A. 

Dixon, Professor Augustus Ed- 
ward, F.C.S. 

Dyson, Frank Watson, M.A. 

Evans, Arthur John, M.A. 

Feilden, Colonel Henry Wemyss. 

Galloway, Professor William, 
F.G.S. 

Groodrich, Edwin S. 

Gray, Professor Thomas, B.Sc. 

Gregory, Professor J. W., D.Sc. 



List of Papers read. 



125 



Hamilton, Professor David James, 

M.D. 
Hardy, William Bate, M.A. 
Harker, Alfred, M.A. 
Harmer, Frederic William, F.6.S. 
Hiern, William Philip, M.A. 
Hills, Edmond Herbert, Captain, 

R.E. 
Hopkinson, Edward, M.A. 
Jackson, Henry Bradwardine, 

Captain, R.N. 
Jukes-Browne, Alfred John, F.6.S. 
Kidston, Robert, F.G.S. 
Knott, Cargill Gilston, D.Sc. 
Letts, Edmund Albert, D.Sc. 
Lewis, Sir William Thomas, Bart., 

M.Inst.C.E. 
MacArthur, John Stewart, F.C.S. 
Macdonald, Hector Munro, M.A. 
Maclean, Magnus, D.Sc. 
MacMunn, Charles Alexander, 

M.D. 
Mallock, Henry Reginald Arnulph. 
Mance, Sir Henry C, CLE. 
Mansergh, James, M.List.C.E. 
Martin, Professor Charles James, 

M.B. 
Masson, Professor Orme, M.A. 
Mather, Thomas. 
Matthey, Edward, F.C.S. 
Maunder, Edward Walter, F.R.A.S. 
Meyrick, Edward, B.A. 
Michell, John Henry, M.A. 
Mill, Hugh Robert, D.Sc. 
Newall, Hugh Frank, M.A. 
Notter, James Lane, Surg. Lieut.- 

CoL, M.D. 
Oliver, John Ryder, Major-General 

(late R.A.), C.M.G. 



Parsons, Frederick Gymer, 
F.R.C.S. 

Payne, Joseph Frank, M.D. 

Perkin, Arthur George. 

Pope, William Jackson. 

Rose, Thomas Kirke, D.Sc. 

Ross, Ronald, Major, M.R.C.S. 

Russell, James Samuel Risien, M.E 

Salomons, Sir David, Bart., M.A. 

Saunders, Edward. 

Schlich, Professor William, CLE. 

Sidgreaves, Rev. Walter, S.J., 
F.RA.S. 

Smith, Fred., Lieut.-Col. 

Smith, James Lorrain, ^LD. 

Smithells, Professor Arthur, B.Sc. 

Stead, John Edward, F.C.S. 

Strahan, Aubrey, M.A. 

Swinburne, James. 

Swinton, Alan Archibald Camp- 
bell, Assoc. M.Inst.C.E. 

Symington, Prof. Johnson, M.D. 

Tarleton, Professor Francis Alex- 
ander, Sc.D. 

Tatham, John F. W., F.R.C.P. 

Thomas, Michael Rogers Oldfield, 
F.Z.S. 

Wager, Harold, F.L.S. 

Walker, James, M.A. 

Waterhouse, James, Maj.-Gen. 

Watkin, Colonel, RA., CB. 

Watson, William, B.Sc. 

Whetham, William C D., M.A. 

WTiite, William Hale, M.D. 

Whitehead, Alfred North, M.A. 

Willey, Arthur, D.Sc. 

Woodhead,Professor German Sims, 
M.D. 

Woodward, Arthur Smith, F.G.S. 



The following Papers were read : — 

I. " Further Observations on Nova Persei." By Sir Norman Lockyer, 
K.C.B., F.R.S. 

n. " Some Physical Properties of Nitric Acid Solutions.*' By V. H. 
Veley, F.R.S., and J. J. Manley. 

1.^ 



126 Hon. R J. Stratt On the Condtietivity of 

III. "The Anatomy of Symmetrical Double Monstrosities in the 

Trout." By Dr. J. F. Gemmill. Communicated by Pro- 
fessor Cleland, F.R.S. 

IV. "Preliminary Communication on the (Estrous Cycle and the 

Formation of the Corpus Luteum in the Sheep." By F. H. A. 
Marshall. Communicated by Professor J. C. Ewart. F.R.S. 

V. "On the Composition and Variations of the Pelvic Plexus in 
Acanthias wd^aris" By R. C. Punnett. Communicated by 
Dr. Gadow, F.RS. 

VI. " On the Heat dissipated by a Platinum Siuface at High Tempera- 
tures. IV. — High-Pressure Gases." By J. E. Petavei.. 
Communicated by Professor Schuster, F.RS. 



" On the Conductivity of Gases under the Becquerel Rays." By 
the Hon. R J. Strutt, Fellow of Trinity College, Cambridge. 
Communicated by Lord Rayleigh, F.RS. Received De- 
cember 15, 1900,— Read February 21, 1901. 

(Abstract ) 

This paper gives an account of experiments on the relative con- 
ductivities of gases under the action of Becquerel radiation from 
various radio-active bodies. 

It is first explained that in order to determine the constants 
fundamentally involved, the following conditions must be complied 
with : — 

(1.) The E.M.F. applied to the conducting gas must be great enough 
to consume all the ions produced by the rays. 

(2.) The pressure of the gas must be low enough to prevent any 
appreciable fraction of the radiation being absorbed by it. 

If this is not so, then the layere of gas nearer the radio-active 
surface are exposed to stronger radiation than those further from it. 
The effective strength of the radiation will thus depend on the absorb- 
ing power of the gas at the particular pressure, and the observed 
ratio of the conductivities of two gases at the same pressure will not 
represent the ratio of their conductivities under radiation of a given 
strength. 

The criterion applied to test whether the absorption was appreciable, 
was to examine the conductivity at different pressures. The range 
was ascertained within which the law of approximate proportionality 
to the pressure held good. In the experiments, care was taken to keep 
the pressure well within that range. 



Onses under the Becquerel Rayn, 



127 



The kinds of radiation employed are there enumerated. They 
include, 

(1.) The most penetrating kind of radiation, from radium — that 
deflectable by the magnet. 

(2.) The easily absorbed kind of radiation from radium, which is 
not so deflectable. 

(3.) and (4.) The radiation from two diflerent samples of polonium. 

(5.) The radiation from uranium salt. 

The method of measurement is then described. It was in outline 
as follows : — 

The layer of the radio-active body was placed at the bottom of a 
shallow brass box containing the gas under investigation. In this box 
and parallel to its flat top was a disc electrode, carried by a brass rod 
passing, air-tight, through an insulating ebonite stopper. The outside 
of the box was maintained at a high potential by a battery of small 
storage cells, and the ciurent through the gas measured by the rate at 
which the potential of the insulated electrode rose, as indicated by a 
quadrant electrometer connected with it. 

"WTien it was desired to use only the penetrating rays from radium, a 
thin copper sheet, 0*007 cm. thick, intervened between the radio-active 
material and the gas. In measuring the relative conductivities of 
two gases, the rate of leak through one was observed at a known 
pressure. The apparatus was then exhausted, and the other gas 
admitted, and the rate of leak through it determined. This last rate 
of leak was corrected, so as to obtain the value which it would have 
had at the same pressure as that at which the first was examined. 
The rates of leak through the two gases were then comparable. 

The mean results were as follows : — 



1 
1 




Belatire conductivity 


. Oaf or vapour. 


Density 
(relative). 


Badium. 


Polonium. 




i 


Pene- 
trating. 


Easily 
absorbed. 


I. 


1 Uranium. 
II. 


I Hvclrofiren 


-0693 


0-157 
1-00 
1-21 
1-57 
1-86 
2 32 
4-b9 
5 18 
5 83 


0-218 
100 

1-92 
3*74 


0-226 

100 

1-16 

1-54 

1-94 

2 04 
4*44 

3 51 
5-84 


219 0-213 


Air (assumed) 

' Oxvffen 


1-00 
1-11 
1-53 
1-86 
2.19 
4-32 


1-00 100 


Carbonic acid 

C^vAnoffen 


1 


Sulphur dioxide 

Ohloroform 


2 03 
3-47 


2 08 


Methjl iodide 

Carbon tetrachloride. . 


' 5 05 
1 6-31 


3-55 



128 Sonie Physical Properties of Nitric Acid Solutions, 

The general conclusions are that, 

(1.) Both the deflectable and undeflectable rays give relative con- 
ductivities nearly, but certainly not quite, equal to the relative 
densities. 

(2.) All the different kinds of luideflectable rays give the same rela- 
tive conductivities, but the deflectable rays give somewhat different 
relative conductivities. 

Both these kinds of rays are in this respect sharply distinguished 
from Rontgen rays, which give relative conductivities several times 
greater than the relative densities in the case of gases containing 
sulphur or the halogens. 



" Some Physical Properties of Nitric Acid Solutiona" By V. H. 
Veley, F.R.S., and J. J. Manley, Daubeny Curator, Magdalen 
College, Oxford. Eeceived February 11, — Read March 7, 
1901. 

(Abstract.) 

The results obtained by the authors on the electric conductivity of 
solutions of nitric acid have led them to continue their investigations 
on other physical properties of the same substance with a view of con- 
firming the conclusions drawn therefrom. 

In thei present paper the properties eicamined are the densities, with 
especial reference to the contractions, and the refractive indices. 

The various sources of error and their possible magnitude are dis- 
cussed in full : for the densities, those of analysis, unavoidable in this 
case, temperature, errors of filling pyknometers both with acid and 
water ; for the refractive indices, those of micrometer screws, diWded 
circle, parallelism of quartz plates are more especially alluded to, as 
also the several effects likely to be produced by the various substances 
with which the acid solutions of necessity came into contact. The 
results obtained by both methods are given in a series of tables, and 
compared with those calculated from various equations for straight 
lines. These show that the physical properties are discontinuous at 
points corresponding very approximately to the concentrations required 
for simple molecular combinations only of nitric acid and water. In 
the case of the densities and contractions, the best defined points of 
discontinuity correspond to the composition of the hydrates with 14, 7, 
4, 3, 1*5, and 1 molecular proportions of water; in the case of the 
refractive indices, the most marked points correspond to the 14, 7, and 
1"5 hydrates. 

The results for the contractions further confirm those for the electric 
conductivities as to a remarkable discontinuity at concentrations 95 per 



Anatomy of Symmetrical Double Monstrosities in the Trout 129 

cent, to 100 per cent., whicli can possibly be explained by some cause 
other than the combination of acid with water. 

The contractions show that these points of discontinuity, though to 
some degree real, yet to another degree are ideal in that there is within 
the limits of 1 to 2 per cent, in the vicinity of such points a transition 
stage. 

The values for /ti are further expressed in terms both of Gladstone 
and Dale's, and of Lorentz' formula, and it is shown that the values in 
neither case are constant, but decrease with increase of concentration, 
and also that Pulfrich's formula which expresses the relation between 
the refractive index and the contraction in terms of a constant is 
only approximately applicable for results differing by small per- 
centage concentrations, but not so in the case of considerable 
differences. 

The results are illustrated by a selection of curves, with especial 
reference to the points of discontinuity. 



' The Anatomy of Symmetrical Double Monstrosities in the 
Trout." By James F. Gemmill, M.A., M.D., Lecturer in 
Embryology and University Assistant in Anatomy, University 
of Glasgow. Communicated by Professor Cleland, F.RS. 
Eeceived February 6, — Eead March 7, 1901. 

(Abstract.) 

This paper contains the results of an investigation into the anatomy 
of a series of trout embryos exhibiting different degrees of symmetrical 
duplicity, and gives an account of the structural details which attend 
the fusion, disappearance, or special adaptation of parts in the region of 
transition from the double to the single condition. Some general 
questions suggested by these results are also discussed. 

The monstrosities examined were four months old counting from 
the time of fertilisation, and they form a fairly complete series ranging 
from specimens in which the duplicity does not affect more than the 
anterior part of the head to specimens in which there is union by the 
posterior part of the body or by the yolk-sac only. The classification 
adopted has special refereiice to the material at my disposal and is on 
the same general lines as that given by Professor Windle in the * Pro 
ceedings of the Zoological Society,' 1895. 

The examination of the monstrosities was necessarily preceded by an 
investigation into the anatomy of normal trout embryos at correspond 
ing stages in development. The results of this investigation are 
briefly given, special attention being paid to the cranial, visceral and 
vertebral skeleton, which at this period is wholly cartilaginous. 



130 Dr. J. F. Gemmill. Tlie Anatomy oj 

The following is a short summary of the anatomy of the various 
kinds of double monstrosity described : — 

Type 1. Union in head region — 

a. The twin brains united at the mesencephalon, 

b. The ttvin brains united at the medulla oblongata. 

Type 2. Union in pectoral region — 

a. The pectoral fins absent on adjacent sides. 

b. The pectoral fins present but united on adjacent sides. 

Type 3. Union behind the pectoral region — 

a. The turn bodies united at a considerahle distance in front of the vent. 

b. The twin bodies united close to the vent. 

Type 4. Union by the yolk-sac only. 

Type \a shows the following characteristics : — 

The cerebral lobes and the thalamencephala are doubled. 

There are two infundibula, two hypophyses and two pairs of hypo- 
aria. The optic lobes have a single cavity, but their basal parts show 
marked evidence of duplicity. Cerebellum pons and medulla are 
single, but there is a remarkable reappearance of duplicity in the cervical 
part of the spinal cord. 

There are two pairs of 1st, 2nd, 3rd (and 4th) nerves, but only 
single pairs of the 5th, 6th, 7th, 8th, and vagus nerves are present. 
The cervical part of the spinal cord gives off in each segment a small 
extra pair of ventral roots. 

There are two pairs of olfactory organs^ all of which are normal. 
There are also two pairs of eyes, the outer ones (right of right head 
and left of left head) being normal. The inner or adjacent eyes (left 
of right head and right of left head) lie close to one another, and are 
more or less united. They have a common sclerotic and cornea, but 
the retinae and choroids are separate. In some cases the lens is a 
single composite structure ; in others it is doubled. Of eye muscles 
the external recti are always, and the superior obliques are sometimes, 
awanting. The other eye muscles are all present, and each eye has 
its own optic nerve, choroidal fissure, choroidal gland and choroidal 
artery. 

In front there are two sets of skeletal structiu*es which converge 
rapidly as one goes backwards. The adjacent trabecular, supraorbital, 
and palatopterygoid bars coalesce posteriorly, while the adjacent para- 
chordals are united along their whole length. There are two pituitary 
spaces. Only a vestige remains of the adjacent Meckelian cartilages. 
The notochords are double in front and remain separate for about 
twenty somites. They retain duplicity longer than any other 
structure. Adjacent neural and costal arch cartilages unite, become 



Symmetrical Double Monstrosities in the Trout, 131 

reduced in size, and finally disappear as one goes backwards. The two 
outer series of cartilages are continued posteriorly into the single region 
of the body. 

Head Kidney, — The glomerulus is sometimes double and sometimes 
single j when single it has two glomerular tufts, and is divided into 
three chambers. Each of the outer chambers gives origin to a normal 
Wolflfian duct. The middle chamber is closed. When there are two 
glomeruli, a normal WolflBian duct arises from the outer half of each 
glomerulus, but the Wolffian ducts which should arise from the inner 
or adjacent sides of the glomeruli are either entirely absent or are 
represented only by short blind sacculated tubules. 

Alimentary Canal. — Two mouth openings lead into a single buccal 
cavity. Pharynx, stomach, liver, and intestine are single, but there 
are two air-bladder diverticula. 



Type 16. Union in Head Region^ the brains being united at the medulla 

oblongata. 

The medulla and the fourth ventricle cavity bifurcate anteriorly 
and lead to two separate sets of mid- and fore-brain cavities and 
masses. Pons and cerebellum are double. There are two sets of 
cranial nerves. The inner or adjacent elements of the 5th, 7th, and 
8th pairs are reduced in size, while the corresponding vagi are 
extremely rudimentary. The anterior part of the medulla is double ; 
the posterior part is single and composite. The cervical part of the 
epinal cord shows striking evidence of original duplicity, and has a set 
of small extra roots coming^off from its ventral aspect as in Type la. 

There are two pairs of olfactory organs and two pairs of eyes, all of 
which are normal. The outer auditory organs (right of right head and 
left of left head) are normal. In addition there is a small malformed 
auditory organ placed in the angle between the two converging heads ; 
it consists of united adjacent labyrinths and capsules, and has dis- 
tributed to it on either side the small adjacent 8th nerves previously 
mentioned. 

Cranial Skeleton, — In front, the cranial skeletal elements are in two 
separate sets ; these converge posteriorly, their basal parts uniting at 
the level of the medulla oblongata. There are thus two separate nasal 
cartilages, two separate sets of trabeculsB cranii and two pituitary 
spaces. The adjacent parachordal cartilages unite and form with the 
outer ones a single plate which underlies the composite medulla 
oblongata and covers the cranial parts of the two notochords. The 
inner or adjacent palatopterygoids, supraorbitals, hyo-mandibulars 
and periotic capsules are united and reduced in size. In the visceral 
skeleton there are elements representing fused adjacent Meckelian and 
hyoid bars, while the copular cartilage which succeeds the glossohyal is 



132 Dr. J. F. Gemmill. The Anatomy of 

bifid anterior^. The notochords remain separate for at least thirty 
somites, and have the same arrangement of neural and costal arch 
cartilages as was described in connection with Type la. 

Hearty &c, — The heart chambers and the truncus arteriosus are 
single, and there are the usual number of gills and gill vessels. There 
are, however, two sets of carotid and hyoid arteries, the inner or 
adjacent pairs being derived directly from the truncus arteriosus. 
The truncus arteriosus arches dorsally in the septum between the two 
mouths to reach the base of the skull, and then divides into two limbs 
which are continued backwards to join the aortic collecting roots on 
either side. The dorsal aorta remains double so long as the notochord 
is double. 

Head Kidney. — There is a large composite glomerulus containing two 
vascular tufts and divided into three compartments. Normal Wolfl&an 
ducts arise from the outer compartments, while the middle one gives 
origin to a coiled sacculated tubule which ends blindly in the tissue of 
the head kidney and represents united adjacent Wolffian ducts. 

The alimentary canal has two mouth openings, two buccal cavities, 
and two air-bladder diverticula. Pharynx, oesophagus, stomach, liver, 
intestine, and vent are single. 

Muscles, — In both (a) and (b), so long as the notochords are separate, 
there exists between and ventral to them a median muscular mass, 
divided into segments corresponding with the mesoblastic somites, 
innervated by the small extra ventral spinal roots previously mentioned, 
and representing united adjacent lateral muscles. 

Type 2. Union in Pectoral Region, 

{a.) Adjacent Pectoral Fins absent, 

(b,) Adjacent Pectoral Fins present , but united. 

In both cases the brains, the cranial and visceral skeletons, the 
organs of sense, and the upper parts of the spinal cords are completely 
doubled. There are two hearts and two trunci arteriosi. In (a) the 
auricles communicate, and the sinus venosus is a large common chamber 
receiving two sets of jugular veins, but receiving only a single pair of 
cardinals. In (b) the auricles are separate, the sinus venosi have only 
a narrow neck of communication, and there are two complete sets of 
jugular and cardinal veins. The inner or adjacent set of cardinals is, 
however, much reduced in size. 

Pectorid Fitis, — In (a) pectoral fins are entirely absent from the 
adjacent sides of the twin bodies ; in (b) they are present in a more or 
less united condition, the union being greatest towards the posterior 
border. 

The head kidney resembles that described for Type 1 (b) ; the median 
tubule is, however, larger, and is continued further backwards. 



Symmetrical Dottble Monstrosities in the TrotU, 133 

Alimentary Canal, — Mouth, pharynx, air bladder and stomach are 
doable. Union takes place in the pyloric region. Liver, intestine and 
vent are single. 

Type 3. Unicn by Posterior Part of Body, 

The intestines are united for a greater or less distance forwards from 
the vent) which is almost always single. The sagittal planes of the 
twin bodies converge ventrally in a degree which, roughly speaking, 
varies directly as the degree of duplicity. The spinal cords may or 
may not unite anterior to the place of union of the notochords. In 
some cases the spinal cords remain separate along their whole length. 
As a rule, in cases where ventral convergence of the sagittal planes is 
well marked, dorsal structures, such as the spinal cords, dorsal fins, and 
dorsal edge membranes, remain double longer than structures which are 
more ventrally placed. 

The twin head kidneys are quite separate, and each gives origin to 
two Wolflfian ducts. The relations of the posterior parts of these ducts 
and of the bladders show remarkable variety. In rare cases the two 
adjacent WolflBan ducts (i.e., left duct of right twin and right duct of 
left twin) end blindly and separately, while the two outer ducts open 
into a single normal bladder. In all other cases there are two bladders, 
each of which receives a right and a left Wolfl&an duct belonging to 
different twins. The two bladders may be quite separate, or they may 
communicate with one another. When they are separate each of them 
may open by a urinary pore, or one of them may have no outlet, and 
may be greatly enlarged through retention. When the bladders 
communicate with each other, only one of them possesses a urinary 
pore. 

The intestines are separate in front, but in all my specimens they 
unite posteriorly. The united part usually ends by a single vent, but 
in one remarkable instance two vents were present which terminated 
by anal orifices situated on opposite sides of the composite body of the 
monstrosity. 

Type 4. Union by Yolk-sac only. 

Each embryo has a complete and separate complement of organs. 
The alimentary canals are shut off altogether from one another and 
from the yolk. The vitelline circulations are crossed. 

General. » 

The general part of the paper discusses briefly — 

(1.) The idiosyncrasies and general arrangement of mesial and 
paired organs at the transitional region in symmetrical double 
monstrosities. 



134 Anatomy of Symmetrical Datible Monstrosities in the Trout. 

(2.) Certain instances of correlation and irregularity in develop- 
ment. Mode of origin of double monstrosities in the trout. 

The discussion under these heads is based on the evidence brought 
forward in the descriptive part of the paper. 

(1.) It is shown that at the region of transition in laterally symmetri- 
cal double monstrosities the notochords are the last structures to unite, 
while equally primitive structures, both dorsal and ventral to the 
notochords, viz., the neural axis and the alimentary canal, lose their 
duplicity earlier. It is further shown that those parts of the neural 
axis and alimentary canal which are most closely apposed to the noto- 
chords retain evidence of original duplicity longer than parts which 
are more remote. The floor and roof of the neiu'al axis and of the 
alimentary canal are seen to be in marked contrast in this respect. 

Duplicity of the dorsal aorta, of the pronephric glomerulus, of the 
vertebral cartilages, of the body muscles and of various other struc- 
tures is correlated with duplicity of the notochord. 

In paired organs the transition from the double to the single condi- 
tion takes place at the expense of the inner or adjacent elements, which 
are usually united and reduced in size before they disappear altogether. 
A list is given of the more important examples of union and reduction 
in size of adjacent elements in the transitional region, which are 
mentioned in the descriptive part of the paper. 

From the evidence brought forward it is inferred that fusion has 
played a not unimportant part in moulding the form of the neural axis 
and the alimentary tract in the transition region. The imion of 
adjacent paired structures is probably to be explained by the fusion of 
mesoblastic blastema developing laterally from each of the embryonic 
axes near the place of convergence and luiion. 

(2.) The law that union takes place between homologous structures 
always holds good. Both twins usually contribute equally and 
symmetrically to the sum of structures in the transitional region. A 
short list of exceptions to this rule is tabulated, but their paucity 
and want of importance only serve to make more striking the general 
symmetry of structure in all the specimens examined. 

With the rarest exceptions, all double monstrosities in the trout are 
examples either of anterior duplicity or of union by the yolk-sac only. 
This contrasts very markedly with the types of double monstrosity 
found in the higher vertebrates, particularly in the birds and mammals. 
An explanation is suggested which depends on the mode of origin of 
the primitive streak in osseous fishes and on the manner in which the 
blastoderm overgrows the yolk mass. 



On the (Estnms Cycle and the CorpiLs Lutetim in the Sheep, 135 



'• Preliinijiary Communication on the QEstrous Cycle and the 
Fonnation of the Corpus Lut^um in the Sheep." By F. H. A. 
Makshall, B.A. Communicated by Professor J. C. Ewart, 
F.RS. Received February 15,— Read March 7, 1901. 

The sheep employed in this research were for the most part half- 
breeds between Cheviots or Leicesters and Scotch Black-faced. Some 
were very kindly kept for me by Professor Ewart at Penycuik, while 
others were obtained from a neighbouring farmer, and killed at various 
intervals after copulation. A quantity of material was also ol)tained 
from the slaughter-house. In all these breeds the lambs are born in 
February or March, and the ewes come into season in the following 
October or November.* Yearling lambs are ready to take the ram 
about the same time. 

Between March and October (period of anoestrum)t the uterus 
remains in the normal condition (the resting stage). A large number 
of ovaries from sheep killed in July and August were examined and 
sections cut, but in no case were there seen either protruding follicles 
or corpora lutea, or follicles beginning to undergo atresia. Moreover, 
the walls of the Fallopian tubes showed no sign of congestion of the 
blood-vessels. Ovaries from sheep killed in the middle of October 
showed that the follicles were nearly approaching ripeness, this being 
indicated by the extent of their protrusion, and a little later burst 
follicles were first observed. From that time to the end of December 
recently ruptured follicles in sheeps' ovaries were quite common. It 
has been found impossible to draw any hard and fast line between the 
prooestrum and obstrus for sheep. The latter follows on the pro(Bstrum 
very quickly, and the two combined are of short duration, probably not 
more than two days. They will here be considered together, as 
certain stages which appear to correspond to those which Heape 
regards as forming part of the procBstrum in other animals occur in 
sheep at or even after the time of copulation. 

At the close of the period of anoestnim certain changes take place 
in the external reproductive organs, the uterus, and the Fallopian 
tubes. The vulva becomes distinctly swollen and congested, and I 
have observed a slight flow of mucus from the external opening, but no 
blood. Subsequent examination of the uterus has shown that l)leeding 
of the uterine wall is extremely slight, but it is, in some cases at any 
rate, undoubtedly present. From an examination of the external 
generative organs it is impossible to determine through what stage of 
the period of growth or period of degeneration the uterus is passing, 

* Dorset sheep alone of British breeds have two gestations a year, 
t Heape, " The Sexual Season in Mammals," * Q. J. M. S./ vol. 44, Norember. 
1900. The terms *' ancastrum," " diasstrum," &c., are here explained. 



136 Mr. F. H. A. Marshall On the OSstrous Cyde and 

nor has it heen, as yet at any rate, possible to state the duration of each 
or all of these stages. The period of growth is marked by the hyper- 
trophy of the uterine stroma by nuclear division, both in and between 
the cotyledons. The nuclei in the early stages are distributed most 
thickly in the region closest to the epithelium of the cotyledons. The 
blood-vessels increase both in size and number, not at first so much in 
the cotyledons as between them, and deeper in the stroma and in the 
muscle layers below the stroma. The uterine cavity, never very large, 
is at this period almost obliterated. The changes above mentioned 
result in the breaking down of certain of the blood-vessels. The blood 
corpuscles thus set free become scattered throughout the stroma, where 
they form irregularly shaped patches and streaks lying a little below 
the epithelium, but I have never seen spaces large enough to be 
described as lacunae. These corpuscles no doubt go largely to form 
pigment,* as supposed by Bonnett and Kazzander.J Only in a few 
places does the epithelium of the cotyledons, as seen in section, lose its 
continuity, and then not more than four or five cells have disappeared. 
Passing to such places may be seen small streams of blood corpuscles 
which were being poured into the uterine cavity. Thus the charac- 
teristics of all Heape's stages from I to VI are more or less clearly 
recognisable. 

The sheep, sections through the uterine wall of which show the last- 
mentioned characters (stage VI), was killed within three hours after 
coition. A Graafian follicle had just ruptured, as was at once appa- 
rent from the bloodstain on its surface, but the blood had not yet 
clotted. Subsequently cut sections revealed the point of rupture, and 
also the ovum and discus proligerus, which had not yet been dehisced. 
It was apparently from such a case as this that Hausmann§ drew the 
conclusion that in sheep ovulation cannot take place without coition. 
That this is not the case, at any rate for the virgin ewe at its first 
oestrus, I subsequently proved. Some yearling lambs were kept along 
with a ram which was rendered temporarily incapable of insemination 
by the method generally followed by sheep breeders. The time when 
the ewes came into season was indicated by their attitude towards the 
ram. (Estrus having been detected by this means, the ewe in 

* Black pigment may not infrequently be obserred, especially between and round 
the bases of the cotyledons, beneath the uterine epithelium. In one case the 
pigment was so distributed as to render the interior of the uterus perfectly black 
between the cotyledons. I have never observed this pigment in the uterus of 
yearling lamb:*. 

t Bonnet. See Ellenbsrger's * Vergleicbende Physiol, d. Haussaugethiere/ vol. 2, 
Berlin, 1892. 

X Kazzander, " tJber d. Pigmentation d. Uterinschleimhaut des Schafes,*' * Arch. 
f. Mikr. Anat./ vol. 36, 1892. 

§ Hausmann, * Ueber die Zeugung und Entstehung des wahren weiblieken 
Xim/ &c., Hanover, ISiO. 



the Formation of the Corpus Luteum in the Sh^^ep, 137 

question was separated from the rest, and a day afterwards killed, 
when it became evident at once from the blood-clot on the surface of 
one of the ovaries that ovulation had recently taken place. Sections 
through this ovary showed the point of rupture of the follicle. This 
fact, that ewes need not be served in order to induce ovoilation, is of 
considerable importance, as it indicates the possibility of obtaining 
saccessful results from the artificial insemination of sheep. 

When ovulation takes place, one follicle only may rupture at a time, 
or one follicle in each ovary, or two in the same ovary. I have never 
observed any greater number of discharged follicles of the same age in 
the ovaries of a sheep.* 

The period of " heat " in sheep is further marked by the distension of 
the blood-vessels of the Fallopian tubes, which may throughout almost 
their entire length be coloured a deep purple. The increased size of 
the vessels is also seen in section, but there is no breaking down of 
vessels. There is too some evidence of increased blood supply to the 
ovaries, apart from the region of the ruptured follicle. 

The changes which take place in the metoestrous period have not as 
yet been fully worked out, but at a period three days after coition, red 
blood corpuscles in a state of haemorrhage, and arranged in streaks 
below the epithelium, have been observed. It would also appear that 
new capillaries have been formed. Metcestrum is succeeded by a 
period of rest (dioestrum), which after not many days is followed by 
another procestrum, and so on, until the sheep becomes pregnant or 
the breeding season is over. The complete dioestrous cycle in the 
sheep in the only case which came under my observation was fifteen 
days, but from the observations of others with whom I have spoken it 
would appear to vary from about thirteen to eighteen days. 

2'he Farviation of the Cm-pus luteum, — The age of the corpus luteiun 
in this investigation was in each case reckoned, either from copulation, 
or, where copulation did not or was not known to have taken place, 
from the time when oestrus was observed. Of course it is possible that 
ovulation does not always take place during oestrus, but the observed 
relation between the state of development of the corpus luteum and 
the time that had elapsed between oestrus and the killing of the animal 
is by itself strong evidence that in the sheep the two phenomena are 
approximately coincident. In no case after a sheep in which oestrus 
had been observed, was killed to obtain a stage in the development of 
the corpus luteum, was the corpus luteum not found. It could 
usually be at once readily detected by the blood-clot which remains on 
the surface of the ovary for several days after the rupture of the 
follicle. 

The corpus luteum of seven hours differs from the unburst follicle 
in its size and in the fact that the ovum and discus proligerus have 
* Triplets are, howorer, not uncommon in some breeds of sheep. 



tS» Mr. F R A. ManhalL On ih$ dbtraus Cyde and 

S^iKi xli^'hAr^l. It w niiher more than half as large as the ripe 
tkv^.to^ An^i cwij^in^ntlr doM not protrude from the surface of the 
H^x«n\ Wry liii)^ M^xxl nraiains within the cavity, but corpuscles are 
^j^N^) A.'^Ttf^r^i tkr^H^ tW memhnuia gnoiuloea, these being derived 
fr^>«n xve^acJiK wh\^A^ w»2l» kan^ hroken down, not only near the point 
x^C n;|V5;TV 04 th* i\\!Ko)fw Urt to a less extent around the whole theca 
*>,w^r^^. "Hie iwentVr^na ^nuiukiHi is approximately twice the thick- 
n<t(RL «>t' i>M) ^^ the rip^ MKoIew »onie of the cells ha^-ing increased 
)Ar^\x •;>, viwN, *hile ^^ker** eje{«ecially those nearest to the periphery, 
*v«v<^v; ?>>^ ^^wrsiv":*** ^^ the ^vri^nal follicular epithelial cells. The 
,v^.^'\v x\^x'^i> A>«\;4ttw a tlui«i resembling in all respects the liquor 
t\v>o<*,s' \^ th^* ^t^J^ there i» no sign of any growth inward of the 
^Va\* ^^^5jv*<^n^ *5Ni I hax^ not obsen-ed any mitoses among the cells of 

tV v\'*^*<w htceum v>t twenty-four hours has undergone considerable 
v.V.^'^NVv U* uxcres^;^ in sise is well marked, its dimensions now ap- 
^v%s*icb^»^< «hvv*e vxf the ripe Graafian follicle. Its shape is generally 
rt J %^uUi\ *uvl tt* walls are much folded. The central cavity is smaller, 
t'hu v'.^vuv, >\huh* as in the earlier stage, contains a fluid, communi- 
vi*uvi \^ rth I ho o.Morior by a slit-like passage opening into a cup-shaped 
Uov c^^'v'u oil iho surfuce of the ovary, from which the corpus luteum 
iK^w .^i»i»ivvu>>ly protrudes. The depression and slit-like passage 
iv^^'.civia iho point of nipture of the follicle. The epithelial wall of 
tKo v'.4\iiy is Ht this period at least twice as thick as that of the 
scNciihvuii- 8taj:;o, this increase being due for the most part to the 
siuiplo hYiH>rtrophy of the individual cells composing it, these appear- 
uiv; lu soviiou two or three times the size of those of the membrana 
>;riuiulvKsii of the Graafian follicle. Division is, however, not very 
infiiHiuoutly to be observed among the epithelial cells. But the thick- 
uoHs kA this layer is also increased by the ingrowth of connective tissue, 
stvtuula i)f which, arising by cell proliferation of the theca interna, are 
growing inwards and penetrating the epitheliiun. These connective 
tissue strands present a radial appearance. The cells of which they 
arc com])osed arc commonly fusiform in shape, and mitotic division is 
very common among them. But although the connective tissue ele- 
ment of the corpus luteum of the sheep is pro\dded chiefly by the pro- 
liferation of the cells of the theca interna, it is in part derived from 
the more fibrous theca externa, from which layer strands of cells, 
usually in close connection with those of the inner layer, are at this 
stage beginning to grow inwards between the epithelial cells. Bed 
blood corpuscles occur in scattered patches and streaks, as in the earlier 
stage. 

In the corpus luteum thirty hours after coition, the inner theca layer 
has all but disappeared, having been used up in the formation of the 
inter-epithelial connective tissue. The epithelial cells, which have still 



tlu Formation of the Corpus Luteum in tlie Sliecp. 139 

further hypertrophied, are now in places surrounded by a network of 
fusiform cells. The point of rupture of the follicle is still open, and 
communicates with the fluid-containing cavity. 

The epithelial cells of the corpus luteum of about fifty hours are 
four or five times the size of those of the undischarged follicle, as seen 
in section. Mitotic division is very rare among them, but evidence of 
it may still occasionally be observed. Proliferation of the connective 
tissue cells continues to take place, chiefly in the direction of the central 
cavity, which has become smaller. Leucocytes are to be seen among 
the epithelial cells, as well as free red corpuscles. The inner theca 
layer, as such, has disappeared. The corpus luteum as a whole pre- 
sents a radial appearance. 

The corpus luteum of sixty hours has undergone a further change. 
The connective tissue cells are dividing in all directions, so that nearly 
every epithelial cell is surrounded by an anastomosis of fusiform cells. 
The central cavity also is completely enclosed by a layer of connective 
tissue. The epithelial cells are still increasing in size by simple hyper- 
trophy, but I have not observed any case of division. Large blood- 
vessels, derived from those of the inner theca, may bo seen in the 
epithelium near the periphery. The corpus luteum is now larger than 
the ripe follicle. 

The succeeding stages in the development of the corpus luteum 
show the still further increase in the connective tissue proliferation, 
and in the hypertrophy of the epithelial cells, and the consequent 
growth in size of the whole structure. The dimensions of the develop- 
ing corpus luteum are, however, no sure guide to its age, for I have 
observed two in the same ovary and of the same age, hut with an 
appreciable difterence in size. Blood vessels, at first only to be 
oWn'ed near the theca interna, spread towards the centre. The 
cavity becomes obliterated by the inward growth of connective tissue, 
and the point of rupture ceases to be visible. The connective tissue 
becomes more and more finely distrilnited throughout the epithelium. 
When the cells of the latter have attained a size of about six times the 
dimensions of those of the unaltered membrana granulosa of the ripe 
follicle, fatty degeneration sets in, and they become converted into 
lutein cells. 

The above account of the development of the corpus luteum in the 
sheep agrees substantially with that given b}' Sobotta* for the mouse 
and the rabbit, and by Stratzt for Tujmia and Tarsius. It ditters from 
Sobotta in the description of the part played by the theca externa, and 
in recording the not infrequently obser\'ed multiplication of the ep!- 

• SobottA, " Ueber die Bildung des Corpus luteum bei ('er Maus," ' Archiv f. 
Mikr. Anat.,' vol. 47, 1896 ; ** Ueber die Bildung des Corpus luteum beim EaniucheD , 
&c.," * Anatomische Hefte/ toI. 8, 1897. 

t Stratz, * Der gescble-.'htsreife Saugetiereierstoclt,' H'lag, 1898. 

VOL. LXVIII. U 



Variaiions of (he Pdvic Plexus in Acanthias vulgaris. 141 

(c) The number of nerves forming the collector ; 

(d) The number and position of the nerve canals ; 

(e) The number of the fin rays ; 

(J) The number of the whole vertebrae. 

(2) Asymmetry occurred in an appreciable number of cases. 

(3) Differences occurred in the two sexes on the following points : 

The position of the girdle is more rostral in the male than in 
the female. The post-girdle fin innervation area is greater in 
the male than in the female, owing to the development of the 
mixipterygium. 

(4) The female is, on the whole, more variable than the male. 

(5) A well-marked correlation exists between — 

(a) The position of the girdle and the number of collector 
nerves ; 

(b) The position of the girdle and the number of post-girdle 
nerves ; 

(r) The position of the girdle and the number of whole 
vertebrae. 

(6) No correlation was found between the niunber of the fin rays an<l 

the number of fin nerves. 

(7) At certain stages in ontogeny the number of collector nerves is 

greater than in the adult. 

(8) At certain stages in ontogeny the number of post-girdle nerves 

is greater than in the adult. The most caudal two or three of 
these form a posterior collector — a structure which is never 
found in the adult. 

The facts recorded have been used iis criteria between the two rival 
theories of limb origin with the following results : — 

(1) To explain the variations on the side-fold excalation theory, it 

miist be assumed that excalation of segments is going on in the 

collector and pre-coUector areas whilst, at the sfime time, intercalation 

is taking place in the post-girdle area ; or, in other words, that the 

portion of the vertebral column in front of the girdle is tending to 

split up into fewer segments, whilst simultaneously that portion }>chind 

the girdle is tending to become divided into more segments. Leaving 

on one side the improbability of two contiguoTis portions of the 

v-ert^bral column undergoing at the same time two opposite processes, 

:\n examination of the number of whole vertebroe associated with 

clifFerent positions of the girdle lends practically no support to the view 

tha.t intercalation is going on in this area. 

(2) ^ On the side-fold excalation theory, an explanation of. the vaiia- 
tions in the position and number of the nerve canals of the girdle, and 
of tlxe occasional instances of asymmetry, necesaitatoa tVve ^^wm^W^xv 

^\ 1 



142 Sir Norman Lockyer. 

that the peivic girdle in different specimens is not homologous — an 
assumption which at present seems unjustifiable. 

(3) The different variations observed are not discordant with the 
view that the limb is capable of migrating along the body, on which 
view it must be supposed that a secondary rostral migration has 
followed a primary caudal one. Moreover, such a view receives 
confirmation from the existence of a posterior collector and of a more 
extensive anterior collector in certain embryonic stages. 



"Further Observations on Nova Persei." By Sir Norman 
Lockyer, K.C.B., F.RS. Eeceived and Eead March 7, 1901. 

[Plate 1.] 

Since th« preliminary note on this star was communicated to the 
Eoyal Society on February 28th, observations have been possible on 
the nights of February 28th, March Ist, 3rd, and 5th, and twenty- 
four photographs of the spectrum have been taken with the instru- 
ments before detailed. 

It may be stated generally that the light is slowly waning. On 
February 28 th the star was only slightly brighter than aPersei. On 
March 1st it was estimated as about equal to aPersei, i.e., about 2*0 
magnitude. When it was again visible on the evening of March 3rd, 
it was distinctly less bright than ^Persei, and its magnitude probably 
near 2*5 ; on the 5th its estimated magnitude was 2*7. 

The a])ove refers to the visual brightness. A photograph of the 
region occupied by the Nova on March 3rd showed it to be photo- 
graphically l)righter than a Persei. 

Genei'al Desci'iption of the Spectrum. 

The photographs show that the bright hydrogen lines are succes- 
sively feebler as the ultra-violet is approached, and the whole of the 
series of hydrogen lines have diuing the past week become relatively 
brighter with respect to the remaining lines and the continuous 
spectrum. The spectrum extends far into the ultra-violet. 

Among the changes which have taken place in the visible part of 
the spectrum, it may be mentioned that while the lines of hydrogen 
have become relatively brighter during the past week, the remaining 
lines, with the possible exception of the prominent one at X5169, have 
become distinctly dimmer. There has also been a diminution of the 
intensity^ of the continuous spectnmi. The line in the yellow, the 
identity of which has not yet been definitely determined, has gradually 
decreased in intensity with the diminution of brightness of the star. 



* 

• '1 



freronee 
^d that 
it*r new 

tions of 

^ged by 
nth the 



E. 



•Hffl aJ 



J 



43 

(3) ^r^Oi 

view tha^^ *^ 
view it __ i 

exteiisiv ^ 



Loci 



^1 



Since 

tbo nigi 
iour p^i^^ 

It mr«*' 

March 1- 1 

it was fl ^ 

near 2 5 ' 

The ai 

regioti O 
graphics* 



•* 



The 1 

aivcly f< 
aeries oi 

ipectrui^ 
Amoi 
the sp0 
have he 
lines, w: 
bceomo 
intensit 
identity 
(. decrease 



FiO'tlur Ohsrrrnf i(niH m// Xnra Prrsi i 14* 

111 the visilJe jjurt of the spettruiu the Ijiight green-hhie F Hue o 
hydrogen has become more conspicuous as the neighbouring greei 
lines have become fainter, and the bright C line is intensely brilliant. 

From all these causes, which give us blue light on the one hand am 
red on the other, the star should present to us the precise quality o 
red which has been observed. 

Colour, 

At discovery the star was described as bluish-white. No observa 
tions on its variation in hue during its brightening were possible 
owing to imfavourable weather conditions. The observations during 
the period of decline have indicated a change to the present colour o 
a decided claret red. In comparison with this, it is interesting to noU 
that in the ease of the Nova which appeared in 1604, Kepler alludes t< 
purple and red tints assumed by the star. 

Changes in the Photographic Spedmnu 

Between February 25th and March 5th, to take the extreme difference 
of dates on which photographs were obtained, it has been noted thai 
while some of the dark lines were absent at the later date, either nein 
lines had come in or previously feeble lines had become intensified 
There has not yet been time to determine accurately the positions oi 
these lines (see Plate 1 ). 

The appearance of the bright lines of hydrogen which I describee 
as being reversed on February 25th, had very materially changed bj; 
March 3rd. 

In inspecting the dark band representing the bright hydrogen at He 
two darker fine lines are seen nearly coincident in position with the 
edges of He in the spectrum of a Persei. 

To my eye the light curve is as follows : — 



Hz 



blue. J Vw re d. 

The appearance is difierent in the case of the F line (HjS), ;i 
light curve of which I also give — 



144 



Sir Norman Lockyer. 



H. 



'fi 



Slue. 




reel. 



No doubt the differences in the appearances are due to the fact that 
at He we are dealing with the lines both of hydrogen and calciunL 

Kough measurements on the bright line H^ show that the intenral 
between the centres of the two extreme maxima shown in the light 
curve corresponds to about 25 tenth-metres. This would give a 
diti'erential velocity of 960 miles per second between the different 
sets of hydrogen atoms in the bright-line swarm itself. 

It may be then that the appearances described as reversals of the 
hydrogen lines on February 25th, were but the beginning of the sub- 
sequent changes. 

The comparisons with stars which have been taken with the slit 
spectroscope on each evening of observation, indicate that no great 
change in the velocity of the dark-line component has occurred. 
. So much, however, cannot be said of the bright lines, in which a 
change has been observed. In addition to the hydrogen lines the 
strong lines in the green already ascribed to iron, appear to l>e double 
in the j)hotographs most recently obtained. 

ComjMirison with x Cijijnx. 

The view of the apparent similarity between the spectra of Nova 
Persei and Nova Aiu-iga^ to which 1 drew attention in mv previous 
paper, has been strengthened by the comparisons which have since 
been made. 

The bright lines in the spectrum of Xova Persei are so broad, 
especially in the blue and violet, that accurate determinations of their 
wave-lengths are difficult to ol)tain. The lines less refrangible than F, 
however, besides being more isolated, are narrower than those in the 
more refrangible part of the spectrum. A direct comparison of these 
with the lines in the spectrum of a star which is known to contain the 
enhanced lines of iron, iK:c., has been considered a better method of 
arriving at some definite conclusion as to the connection between the 
Nova lines and the enhanced lines, than that of determining the wave- 
lengths of the broad lines and comparing the results with the known 
wave-lengths of the enhanced lines. 



Farther Observatioiis on Nova Fersei 145 

The best star for this purpose is a Cygni, but unfortunately no good 
photograph has been obtained at Kensington of the green portion of 
the spectrum of that star. The star most nearly approaching a Cygni 
in relation to enhanced lines is a Canis Majoris, which in the 
Kensington classification has been placed nearly on a level with the 
former star, but on the descending side of the temperature curve. In 
the spectrum of this star the enhanced lines of iron XX 4924*11, 

5018-63, {5169.22 ^^^ 5316-79 occur as well-marked lines. This 

spectrum has been directly compared with that of Nova Persei taken 
with the same instrument, and the fact that all the lines apparently 
coincide, affords good evidence that the connection is a real one, and 
that the first four strong Nova lines beyond F on the less refrangible 
side are the representatives of the enhanced lines of iron. These are 
the only enhanced lines which occur in that part of the iron spectrum, 
with the exception of a weak one at X 5276-17. There is only a trace 
of this line in the spectra of either the Nova or a Canis Majoris which 
have been compared. In the spectra of the Nova obtained with lower 
dispersion, however, a line is distinctly shown in this position, though 
it is considerably weaker than the four lines previously mentioned. 

The absence of the strong lines which are familiar in the arc spec- 
trum, and in the ordinary spark spectrum in this region, is to be 
ascribed to higher temperature; experiments which are in progress 
show that under certain conditions, the two lines X 5018*6 and 
X5169 are by far the strongest lines in the spectrum of iron between 
X 500 and D, while that at X 4924-1 is distinctly stronger than any of 
the well-known group of four arc lines in which it falls. 

The published wave-lengths of the lines of Nova Aurigse show that 
the same lines were present in that star. Further investigations of 
the spectrum of Nova Aui-ig» have strengthened the conclusion that 
most of the lines, after we pass from those of hydrogen, are enhanced 
lines of a comparatively small number of metals. 

When the inquiry is extended into the region more refrangible 
than H^, the evidence in favour of the similarity of the spectra of the 
two Novae with that of a Cygni is not so conchisive, because of the 
greater breadth of the lines (since the spectra have been obtained by 
the use of prisms) and because of the fact that in this regi<jn the 
enhanced lines of iron frequently occur in groups. 

In the region between US and lly, however, there is a well marked 
fflihanced line of iron at X 4233*3 and also two doubles at XX 4173*7, 
4179-0, and XX 4296*7, 4303*3, and a comparison of a Cygni with 
Nova Persei indicates that these fall on broad bright bands of the 
Nova spectrum. 

It is not claimed that all the enhanced lines which appear in the 
spectrum of a Cygni are represented in that of Nova Auriga*. There 



146 Meeting of March 14, 1901, and List of Papers read, 

is, however, a suflScient reason why at a particular stage in the 
spectn.m ol such Novae the enhanced lines of certain substances 
should predominate. Thus, in y Cygni, titanium is most strongly 
represented by enhanced lines ; in a Cygni, iron, chromium, and nickel ; 
in P Orionis, silicium and magnesium, and so on. We may thus 
expect to find the lines of different substances most prominent at 
different stages in the history of the star. 

In the work above referred to I have been assisted as follows : — 
The new photographs have been taken by Dr. Lockyer and Messrs. 
Fowler, Baxandall, Shackleton, Butler, Shaw, and Hodgson. The 
detailed examination of the photographs has been made by Messrs. 
Fowler and Baxandall. The visual observations have been chiefly 
made by Messrs. Fowler and Butler. The photographs have been en- 
larged and the illustrations for this paper prepared by Sapper Wilkie. 
To all, my best thanks are due. 



March 14, 1901. 

Sir WILLIAM IIUGGIXS, K.C.B., D.C.L., President, in the Chair. 

A List of the Presents received was laid on the tiible, and thanks 
ordered for them. 

The followhig Papers were read : — 

I. ** The Action of Magnetised Electrodes upon Electrical Discharge 
Phenomena in Karefied Gases.'* By C. E. S. Phillips. Com- 
municated by Sir W. Crookes, F.K.S. 

II. ** The Chemistry of Nerve-degeneration." By Dr. Mott, F.K.S., 
and IVofessor Halliburton, F.K.S. 

III. " On the lonisation of Atmospheric Air." By C. T. K. Wilson, 

F.K.S. 

IV. " On the Preparation of Large Quantities of Tellurium." By 

E. Matthey. Commimicafed by Sir George Stokes, Bart., 
F.R.S. 



aiectincal Discharge Phenomena in Rarefied Gases. 147 



" The Action of Magnetised Electrodes upon Electrical Discharge 
Plienomena in IJareiied Gases." By C. E. S. Philups. Com- 
municated by Sir William Ckookes, F.R.S. Received 
February 28,— Read March 14, 1901. 

(Abstract.) 

A preliminary account of this investigation has already been laid 
before the Society.* The present paper deals more particularly with 
the conditions necessary for the production of a luminous ring in 
rarefied gases and under the influence of electrostatic and magnetic 
forces. 

The cause of the luminous phenomenon is traced to the action of the 
magnetic field upon electrified gaseous particles within the rarefied 
space, and experimental evidence is given to show that the rate of 
change of the magnetic lines is an important factor. 

Numerous experiments relating to the loss of positive electrification 
from a charged body when placed in a rarefied space, and in the 
neighbourhood of a magnetic field, are also described in detail, t 

An apparatus similar to that referred to in a previous communica- 
tion was generally found most suitable for observing the formation 
and behavioiu* of the luminous ring. It consisted of a small spherical 
glass bulb 2*5 inches in diameter, and provided with short projecting 
necks for the purpose of carrying two oppositely placed soft iron rods. 
These rods were pushed one through each of the short tubes, cemented 
in position, and arranged to have their pointed ends within the bulb and 
a sixteenth of an inch apart. 

The cores of two electro-magnets wore then butted against the 
external ends of the rods, for the piu-pose of magnetising them when 
required. 

When the gas within the bulb had been rarefied to a pressure of 
about 0*005 mm. of mercury, a discharge from an induction coil was 
sent through it for a few seconds, the rods (now used as electrodes) 
meanwhile remaining immagnetised. But when the discharge was 
stopped and the magnets were excited, a luminous ring appeared 
within the bulb, in a plane at right angles to the magnetic axis, 
between the pointed ends of the electrodes, and in rotation about the 
lines of magnetic induction. 

The luminosity of the ring was found to be intermittent, its spectrum 
showed no peculiarity, and it was not possible to obtain satisfactory 
photographs of the revolving glow. In oxygen the ring appeared a 
little brighter, but in hydrogen or carbonic dioxide the luminosity 
seemed about the same as in air. 

• * Roy. 8oc. Proc.,* toI. 64, p. 172. 
t * Roy. 6oc. Proc.,* rol. 65, p. 320. 



148 Electrical Discharge Fhenonietui in Rarefied Gases, 

Two or more rings could bo made to appear by placing an electri- 
fied platinimi circle of wire equatorially within the bulb. When the 
platinum circle was negatively electrified, the luminous ring was 
repelled by it. In this manner the ring itself was invariably shown 
to be negatively electrified. Its direction of rotation was found to be 
that of the current induced in a loop of wire when the loop is suddenly 
moved up to a north magnetic pole — clockwise, looking through the 
loop at the pole. The outside of the glass bulb was always negatively 
electrified when a luminous ring appeared in the interior. This 
pointed to the removal of a layer of positively electrified gas from 
the inner surface of the bulb through the action of the magnetic field. 
Although such radial streams of positive ions so produced might 
accoimt for the luminosity of the ring through their collisions with an 
accumulation of negative ions at the more central part of the bulb, 
they would not have produced rotation of the luminous ring in the 
direction already observed. The incoming radial streams of positive 
ions were studied in detail with an ap^mratus more suitable for 
examining the diselectrifying action of the magnetic field. Those 
experiments established two facts, viz., that the loss of positive electri- 
fication from charged bodies is brought about by the magnet, through 
the concentration of negative ions which occurs at the strongest part 
of the magnetic field immediately the electrodes are magnetised, and 
also that the luminosity of the ring itself is due largely to the collisions 
between the incoming streams of positive ions and this accumulation 
of negatively electrified gas between the j^ointed ends of the electrodes. 
A potential difl'erence is thus set up within the bulb between the 
negative gas -mass at the centre and the positively electrified layer of 
ions residing upon the inner surface of the glass, which rapidly reaches 
a value sufiicieut to give rise to a discharge through the residual gas. 
It is then that the positive ions stream inwards, accompanied by a 
corresponding outward- moving whirl of negative ions. 

Experiments upon the effect of causing the magnetic field to either 
slowly or rapidly reach its maximum value, as well as diminish either 
slowly or rapidly to zero, have shown that the rate of change of the 
magnetic lines plays an important piirt in the actions here described. 
A very rapidly growing field woidd diselectrify a positively charged 
body, whereas, when the magnets were slowly increased in strength 
there was no diselectrification in such cases. In certain experiments, 
the act of suddenly destroying the magnetic field produced diselectri- 
fication, while if the current were slowly diminished in the coils of the 
electro-magnets there was no evidence of any such effect. 

Both the luminous ring and the diselectrification phenomena are 
attributable to the same causes. The direction of rotation of the ring, 
however, forms a difficulty, on the assimiption that a rapidly moving 
ion is equivalent to a ciu*rent along a flexible conductor. Incoming 



The Chemistry of Nerve-defjoieration, 149 

streams of positive ions would give a direction opposite to that 
observed, and if the rotation were produced by the changing strength 
of the magnetic field upon the negative ions, then also would the 
direction of rotation be opposite to that actually obtained. The 
viscosity of the gas would tend to annul any sudden twist which the 
changing magnetic field might give to the cloud of negative ions 
within the bulb, although the reaction set up between the magnets 
and the ions under such conditions would be sufl&cient to cause the 
negative particles to be thrown forward, and to concentrate in a 
manner consistent with the experimental results given. It is not clear, 
however, why the sudden cessation of the magnetic field should also 
produce such a concentration of negative ions. But we have already 
seen that under those conditions diselectrifi cation is easily produced ; 
moreover, a luminous ring that has grown dim, can usually be momen- 
tarily brightened by suddenly destroying the magnetic field. 

A pause was sometimes noticed between the excitation of the 
magnets and either the formation of the ring or the loss of charge 
from a positively electrified body. 

This result showed that the steady magnetic field itself so modified 
the paths of moving negative ions within the bulb, that a concentra- 
tion of them at the strongest part of the field took place for this reason 
also. 

The direction of rotation of the luminous ring can be accounted for 
in the following manner : — 

When the potential dift'erence between the accumulation of negative 
ions at the centre of the bulb and the layer of electrified gas upon the 
inner surface of the ghiss is such that a shower of incoming positive 
ions occurs and the luminous ring appears, the outer portion of the ring 
will be more positive than the surrounding negatively electrified cloud 
of gaseous particles. These will therefore lje attracted inwards, and in 
that way give a rotator}' motion to the luminous gas-mjiss in the 
direction actually observed. 



"The Chemistry of Nerve-degeneration." By F. W. MoTT, M.D., 
F.RS., and W. D. Halubuuton, M.d!, F.K.S. Beceived 
March 1,— Bead March 14, 1001. 

(Abstract.) 

We have previously shown that in the disease, Gonoral Paralysis of 
the Insane, the marked degeneration that occurs in the brain is accom- 
panied by the passing of the products of degeneration into the cerebro- 
spinal fluid. Of these, nucleo-proteid and choline are those which can 
be most readily detected. Choline can also be foimd in the blood. 



150 The Chemidry qf Nei^e^^'grn^ration. 

We have continued our work, and we find that thia is not peculiar to 
the disease just mentioned, but that in various other degenerative 
nen^ous diseases (combined sclerosb, disseminated sclerosis, alcoholic 
neuritis, beri-beri) choline /can also be detected in the blood. The 
tests we have employed to detect choline are mainly two: (1) a 
chemical test, namely, the obtaining of the characteristic octahedral 
crystals of the platinum double salt from the alcoholic extract of the 
blood ; (2) a physiological test, namely, the lowering of blood pressure 
(partly cardiac in origin, and partly due to dilatation of peripheral 
vessels) which a saline solution of the residue of the alcoholic extract 
produces ; this fallis abolished, or even replaced by a rise of arterial 
pressure, if the animal has been atropinised. It is possible that such 
tests may be of diagnostic value in the distinction between organic and 
so-called functional diseases of the nervous system. The chemical test 
can frequently be obtained with 10 c.c. of blood. 

A similar condition was produced artificially in cats by a division of 
both sciatic nerves, and is most marked in those animals in which the 
degenerative process is at its height, as tested histologically by the 
Marchi reaction. A chemical analysis of the nerves themselves was 
also made. A series of eighteen cats was taken, both sciatic nerves 
divided, and the animals subsequently killed at inter\^al8 varying from 
1 to 106 days. The nerves remain practically normal as long as they 
remain irritable, that is, up to three days after the operation. They 
then show a progressive increase in the percentage of water, and a 
progressive decrease in the percentage of phosphonis, until degenera- 
tion is complete. When regeneration occurs, the nerves return approxi- 
mately to their previous chemical condition. The chemical explanation 
of the Marchi reaction appears to be the replacement of phosphorised 
by non-phosphorised fat. \Mien the Marchi reaction disappears in the 
later stages of degeneration, the non-phosphorised fat has been absorbed. 
This absorption occurs earlier in the peripheral nerves than in the 
central nervous system. 

This confirms previous obsen'ations by one of us (M.) in the spinal 
cord in which unilateral degeneration of the pyramidal tract by brain 
lesions produced an increase of water and a dimiimtion of phosphorus 
in the degenerated side of the cord, which stained by the Marchi 
reaction. 

The full paper is illustrated by tracings of the effects on arterial 
pressure of the choline separated out from the blood of the cases 
of nervous disease mentioned, and from the blood of the cats 
operated on. 

Tables are also given of the analyses of the nerves, and drawings 
and photo-micrographs from histological specimens of the nerves. 

A simimary giving the main results of the experiments on animals 
is shown in the following table : — 



On tfie lonisation of Atmosplienc Air. 



151 



ft After 



-27 



—106. 



CaU* sciatic nerves. 



Percentage 
Water. SoUds. . ?L???": 




72 1 
72*5 



27 
27-5 



72 6 27-4 



66 2 33-8 



traces 


0-0 
0-9 



Condition of 
blood. 



{Minimal traces 
of choline 
present. 
Choline more 
abundant. 



{Choline 
ddnt. 



abii 



I Choline mucli 



Choline nlnio^t 
disappdaied. 



Condition of 
nerves. 



{Nerves irritable 
and histologi- 
cally healthy. 
IrritabUity lost ; 
degeneration be- 
(ginning. 

{Degeneration well 
shown by Mar- 
chi reaction, 
f March i reaction 
j still seen, but 
\ absorption of 
degenerated fat 
(^ has set in.. 
Absorption of fat 
practically com- 
plete. 
Return of func- 
tion ; nerves re- 
generated. 



. the lonisat'.on of Atmospheric Air." By C. T. E. WiLSOX, 
M.A.. F.RS., Fellow of Sidney Sussex College, Cambridge. 
Received February 1, — Eead March 14, 1901. 

le present communication contains an account of some of the 
Its of investigations undertaken for the Meteorological Council 

the object of throwing light on the phenomena of atmospheric 
licity. 

I a paper* containing an account of the results arrived at during 
earlier stages of the investigation, I described the behaviour of 
tdvely and negatively charged ions as nuclei on which water vapour 

condense. 

lie question whether free ions are likely to occur under such con- 
»iis as would make these experimental results applicable to the 
anation of atmospheric phenomena was left undecided in that 
ir. My first experimentst on condensation phenomena had, it is 
, proved that in ordinary dust-free moist air, a very few nuclei are 

• 'Phil. Trans./ A., rol. 193, pp. 289-308. 
t ' Roy. Soc. Proc.,* rol. 69, p. 838, 1896. 



152 



Mr. C. T. R. Wilson. 



always present requinng, in order that water sho^ condense upon 
them, exactly the same degree of supersiituration Jb the nuclei pro- 
duced in enormously greater inin)liers liy KAteoh rays; and I con- 
c hided that they arc identical with thcai in iHP^c and that they are 
probably ions.* While, however, J|Jit^iIHTt1jn<]i^s ]iro\ed that the 
nuclei formed by Koiitgcu or Tira^^^Hh|^^^ he f^moved by &n 
electric field and are therefore ioii:^, si^^^^^Bemnent:^ made with the 
nuclei which occur in the a1)senc6 of f^^^^^nuUatiort led to negative 
results. t In the light of facts brongJ[|P^J^^f the present paper I 
should now feel disposed to attribute the negative character of the 
results in the latter case to the small number of nuclei present. J 

Subsequently to the publication of the work on the behanour of 
ions as condensation nuclei, Elst^r and Geit<;l showed that an electri- 
fied conductor exposed in the open air or in a room lost its charge by 
leakage through the air ; and that the facts concerning this conduction 
of electricity through the air are most reiidily explained on the suppo- 
sition that positively and negatively charged ions are present in the 
atmosphere. The question where and how these ions arc produced 
remained, however, uiideterniiued : it would therefore Ikj incorrect to 
assume their properties, ;ui(l in pai-tieular their l»chaviour as con<lensa- 
tion nuclei, to bo iiccos.sarily identical with those of frcshl}' pro<luced 
ions: the carriers of the eharge niiglit consist of much more consider- 
able aggregates of mat lei- than those attached to the ions with whiih 
the condensation expeiinients had l)ecn concerned. Moreover, so long 
as the source and eondiiions of production of these ions remained 
undetennined, one could not assume their presence in the regions of 
the atmosphere where supersaturation might he expected to occiu*. 

Before going further afiehl in ser.rcb of possible sources of ionis;ition 
of the atmospheric air, it seemed advisable to make further attempts to 
determine whether a certain degree of ionisation might not I>e a 
normal property of air, in spite of the somewhat ambiguous results 
given by the condensation experiments to which I have referred. 

After much time liad been spent in attempts to devise some satis- 
factory method of obtaining a continuous production of drops from the 
supersaturated condition, 1 abandoned the condensation method, and 
resolved to tr}- the ])urely (^lectiical method of detecting ionisation. 
Attacked from this side tiie pioblem resolves itself into the question. 
Does an insulated-charged conductor suspended within a closed vessel 
containing dust-free aii- lose its charge otherwise than through its 
supports, when its potential is well below that required to canrt 
luminous discharges ? 

* * Caml). Phil. ?or. Pi-o<- ,' r«.l. 0, p. 337. 
t 'Phil. TruTi^.,' A, vd. V, 3, p|.. 2^9 308. 

X Tlie Hiiuilar rrsults obtaint-d with, luiclei produced in air exposed to ultn- 
violet light !C<iuiro, howLVcr, Fomc o\\\er explanation. 






On the lonisation of Atmospheric Air, 153 

Several investigators from the time of Coulomb onwards have 
believed that there is a loss of electricity from a charged body 
suspended in air in a closed vessel in addition to what can be 
accounted for by leakage through the supports.* In recent years, how- 
ever, the generally accepted view seems to have been that such leakage 
through the air is to be attributed to the convection of the charge by 
dust particles. 

The experiments were begun in July, 1900, and immediately led to 
positive results. A summary of the principal conclusions then arrived 
at was given in a preliminary note "On the Leakage of Electricity 
through Dust-free Air," read before the Cambridge Philosophical 
Society on November 26. Almost simultaneously a paper by Geitcl 
appeared in the * Physikalische Zeitschrift 't on the same subject, in 
which identical conclusions were arrived at in spite of great differences 
in the methods employed. 

The following are the results included in the preliminary note, which 
I read: — 

(1.) If a charged conductor be suspended in a vessel containing 

dust-free air, there is a continual leakage of electricity from 

the conductor through the air. 
(2.) The leakage takes place in the dark at the same rate as in 

diffuse daylight. 
(3.) The rate of leak is the same for positive as for negative 

charges. 
(4.) The quantity lost per second is the same when the initial 

potential is 120 volts as when it is 210 volts. 
(5.) The rate of leak is approximately proportional to the pressure. 
(6.) The loss of charge per second is such as would result from the 

production of about 20 ions of either sign in each c.c. per 

second, in air at atmospheric pressure. 

Of these conclusions, the first four were also arrived at by Geitel. 

As Geitel has pointed out, Matteucci,! as early as 1850, had arrived 
at the conclusion that the rate of loss of electricity is independent of 
the potential. He had also noticed the decrease in the leakage as the 
pressure is lowered.§ 

The volume of air used in my experiments was small, less than 
^K)0 c.c. in every case, many of the measurements being made with a 

♦ Perliaps the most convincing evidence of this is furnished bv the experiments 
of ProOwsor Boyp, described in n paper on ** Quartz as an Insulator " (* Phil. Mag.,' 
vol. 28, p. U, 1889). 

t • Physikalische Zeitschrift/ 2 Jahrgang, So, 8, pp. 116—119 (published 
H'orember 24). 

X ' Annalcs de Chira. et de Phvs./ yol. 28, p. 385, 1850. 

§ This was also obserred by Warburg (*Anralen der Physik u. Chemie/ vol. 
XA6, p. 578, 1872). 



154 Mr. C. T. R Wilson. 

vessel containing only 163 c.c. This made it much more easy to 
ensure the freedom of the air from dust particles. Geitel worked with 
volumes amoiuiting to about 30 litres ; his observations show the 
interesting phenomenon of a gradual increase of the conductivity of the 
air in the vessel towards a limiting value, which was only attained 
when the air had 1>cen standing in the vessel for several days. This, 
as Geitel points out, is to be explained by the gradual settling of the 
dust particles, the conductivity of the air being greatest when there 
are no dust particles present to entangle the ions. 

The principal difficulty in the way of obtaining a decisive answer to 
the question whether any leakage of electricity takes place through 
dust-free air is the fact that one is so lia])le to be misled by the leak- 
age due to the insulating support. As will be seen from the descrip- 
tion which follows, this source of uncertainty was entirely eliminated 
in the method which I adopted. It had, moreover, the advantage d 
reducing to the smallest possible value the capacity of the conducting 
system in which any loss of charge is measured by the fall of 
potential. 

The conducting system, from which any leakage is to Ije detected 
and measiu-ed, consists solely of a narrow mctAl strip (with a narrow 
gold leaf attached to indicate the potential), fixed by means of a small 
bead of sulphur to a conducting rod which is maintained at a constant 
potential, equal to the initial potential of the gold leaf and strip. 
With this arrangement, if any continuous fall of potential is indicated 
liy the gold leaf, it can only be due to leakage through the air ; any 
conduction l)y way of the sulphur bead can only be in such a direction 
as to cause the leakage through the air to be under-estimated. 

The form of apparatus used in all the later experiments is indicated 
in fig. 1. The gold leaf and thin brass strip to which it was attachpl 
were placed within a thin glass bulb of 163 c.c. capacity; the inner 
surface of the bulb l)eing coated with a layer of silver so thin that the 
gold leaf could readily })e seen through the silvered glass. The upper 
end of the strip had a narrow prolongation, by means of which it wa? 
attached by a sulphur bead of about '2 mm. in diameter to the lower 
end of the brass supporting rod. The latter piissed axially through 
the neck of the l)ulb, its lower end just rwiching to the point where 
the neck joined the bulb. The interior of the neck of the bulb was 
thickly silvered to secure efficient electrical connection between the 
thin silver coating of the inside of the bulb and a platinum ii^-ire scaled 
through the side of the tube. The platiiumi wire was connected to 
the earthed terminal of a condenser consisting of zinc plates embedded 
in sulphur, the other tenninal of the condenser l>eing connected to the 
brass supporting rod and maintaining it at a nearly constant potential 
An Exner electroscope connected to the same terminal of the cofr 
denser was used to test the constancy of the potential, and any h* 



On the lonisation of Atmospheric Air, 



155 



could from time to time be made up by contact with a rubbed ebonite 
rod or a miniature electrophorus. 

Both the gold leaf of which the motion served to measure the 
leakage which was the subject of investigation, and that of the Exner 
electrometer, were read by means of microscopes provided with eye- 
piece micrometers. 

To give the leaking system an initial potential equal to that of the 
supporting rod, momentary electrical connection between them was 
made by means of a magnetic contact-maker. This consisted of a fine 
steel wire fixed to the supporting rod near its upper end and extend- 
ing just below the sulphur bead, where it was bent into a loop 

Fig. 1. 




Earth. 



EdLTth. 



surrounding the prolongation of the brass strip which carried the gold 
leaf. A magnet brought near the outside of the tube attracted the 
"wire till the loop came in contact with the brass and brought it into 
electrical communication with the supporting rod. This operation 
-was repeated every time the potential of the leaking system had fallen 
so far that the gold leaf approached the lower end of the scale. The 
potential of the supporting rod was not allowed to vary by more than 
9k very few volts, and before each reading of the potential of the leak- 
ing system was always brought to within a fraction of a volt of its 
itutial value ; the Exner electroscope served to indicate when this was 
the case. The initial difference of potential used in most of the 
Experiments amounted to about 200 volts. 

To determine the fall in potential corresponding to a movement of 
VOL. LXVIII. 1^ 



156 Mr. C. T. E. Wilson. 

the gold leaf through one scale division, a series of Clark cells was 
inserted between the condenser and its earth connection, and the 
number of scale divisions through which the gold leaf moved on 
reversing the Clark cells was determined ; contact between the leaking 
system and its supporting rod Ijeing of course made before and after 
the reversal. The scale values of the Exner electrometer were deter- 
mined similarly. 

In the apparatus now described, a movement of the gold leaf of the 
leaking system thiough one scale division corresponded to a fall of 
potential ranging from 0*50 volt at the top of the micrometer scale 
to 0*60 volt at the l)ottom of the scale. 

Any imperfection in the insulating power of the sulphur bead will, 
as we have seen, tend to give too low a value for the leakage. The 
error thus introduced was, however, found to be negligible ; for the 
rate of fall of potential of the leaking system was sensibly the same 
when its potential was equal to that of the supporting rod as towards 
the close of an experiment when this difference wiis greatest. 

The apparatus used in the earlier experiments differed in some 
resjwcts fiom that which has just been described. The vessel was of 
brass in the form of a short cylinder, G cm. long and 5 cm. in radius, 
the flat en<ls licing vertical, each being provided with a rectangular 
window dosed by a glass plate, so that the position of the gold leaf 
might be read. A purely niethanical contact-maker was used instead 
of the magnetic one. With the voltage usually employed, a move- 
ment of the gold leaf over one stale division corresponded to a change 
of potential of OSC volt. 

"With this appai-atus, filled with air at atmospheric pressure (whether 
this had l>een filtered or had merely been allowed to stand for some 
hours in the apparatiLs), a continuous fall of potential of about 4*0 
volts per hour occuried, showing no tendency to diminish even after 
many weeks. Contact had to be made with the supporting rod (kept 
as described at constant potential by means of the condenser) about 
once in twelve hours to prevent the image of the gold leaf from going 
off the scale of the microscope. 

Although care had l)cen taken to avoi<l bringing the apparatus, during 
or after its construction, into any room where radio-active substances 
liad been used, it was considered desirable to repeat the experiments 
elsewhere than in the Cavendish Laboratory (where contamination by 
such substances nn'ght be feared), and with pure coinitry air in the 
apparatus. Experiments were therefore carried out at Peebles during 
the month of September, but with the same results as before obtained. 

The rate of leakage was the same during the night as during the 
day, and was not diminished by completely darkening the room ia 
which the experiments were carried out. It is plainly, therefore, not 
due to the action of light. 



On the lonisation of Atmospheric Air. 157 

It might be considered as possible that the conducting power of 
the air was due to some effect of the walls of the apparatus, related 
perhaps to the Russell* photographic effect and the nucleus-producingt 
effects of metals. These effects, however, are in the case of brass 
certainly very slight (I have not been able to detect any cloud-miclei 
arising from the presence of brass) ; they are enormously greater in 
the case of amalgamated zinc. Yet the presence of a piece of amal- 
gamated zinc "in the apparatus was without effect on the rate of 
leak. If then the walls of the vessel influence in any way the 
ionisation of the air in the vessel, this influence is not proportional 
to the photographic or nucleus-producing effects of the metals. 

To find the loss of electricity corresponding to the observed fall of 
potential of the leaking system, the condenser was removed, and the 
capacity of the Exner electroscope, with the connecting wires and the 
rod supporting the leaking system, was first determined by finding the 
fall of potential resulting from contact with a brass sphere of which 
the radius was 2-13 cm. The sphere, suspended by a silk thread, was 
in contact with a thin earth-connected wire, except when momentarily 
drawn aside by a second silk thread and brought into contact with 
the end of another thin wire leading to the electroscope. Except for 
these two wires the sphere was at a distance great compared with its 
radios from all other conductors. The rise of potential which occiu-red 
in the leaking system after a momentary contact with the system con- 
sisting of the supporting rod, electroscope, and connecting wires was 
then compared with the simultaneous fall of potential of the latter 
system. The loss of electricity corresponding to a given fall of 
potential of the leaking system was thus obtained. It was found to 
be sensibly the same for potentials in the neighbourhood of 100 volts as 
for the higher voltages (about 200 volts) generally used, the variations 
in capacity due to the change of position of the gold leaf being too 
small to be detected. The system had a practically constant capacity 
equal to I'l cm. 

It was possible now to compare the rates of leakage for different 
strengths of the electric field. 

Brass apparatus used, air at atmospheric pessure. 



litial difference of 
potential. 


Fall of potential 
per hour. 


210 volts. 


4 • 1 volts. 


120 „ 


4-0 „ 



The leakage of electricity through the air is thus the same for a poten- 
tial difference between the leaking system and the walls of the vessel 
of 210 volts as for one of 120 volts. On the view that the conduction 

• BuiBoll, ' Roy. Soc. Proc./ vol. 61, p. 424, 1897; vol. 63, p. 102, 1898. 
t WiUon, * PhU. Trans.,' A, vol. 192, p. 431. 



158 Mr, C. T. R Wilson. 

is due to tho continual production of ions throughout the air, tiiis is 
easily explained as indicating that the saturation current has been 
attained ; the field being sufficiently strong to cause practically all the 
ions which are produced to reach the electrodes ; the number destroyed 
by I ecombination being negligible in comparison with those removed 
by contact with the electrodes. Thus under the conditions of the 
experiments the loss of electricity from the leaking system in a given 
time is, if tho charge be positive, equal to the total charge carried by 
all the negative ions produced in the vessel in that time. 

The sum of the charges of all the negative ions (or of all the positive 
ions) set free in the vessel is thus 1*1 x 4*1/300 E.U. per hour, or 
■4*3 X 10"^ E.U. per second. If we divide by 471, the volume of the 
vessel in c.c, we obtain for the charge on all the ions of each sign set 
free in each c.c. per second, 9*1 x 10"^* E.U. Finally, taking 
6*5 X 10"^^ E.U., the value found by J. J. Thomson, as the charge on 
one ion, we find that about 14 ions of each sign are produced in each 
c.c. per second. 

There are, however, two defects in the older form of apparatus, 
with which the above results were obtained, tending to make this 
number too small ; firstly, tho field in the corners where the flat ends 
meet the cylindrical wall must be very much weaker than elsewhere, 
and some of the ions set free in these regions may have time to recom- 
bine, although the strength of the field throughout most of the vessel is 
more than sufficient for ** saturation" ; secondly, since in this apparatus 
both the rod supporting the leaking system and the contact-maker 
projected for about a centimetre into the interior of the vessel, » 
certain proportion of the ions set free would be caught by them and 
not by the leaking system. 

These defects are avoided in the other apparatus which has been 
described (fig. 1). 

In this apparatus the capacity of the leaking system was 0*73 cm. 
The constant potential of tho supporting rod, and thus the initiil 
potential of the leaking system, was in all cases about 220 volts. 

At atmospheric pressure the fall of potential per hoiu* was found to 
be 2-9 volts. The loss of charge was therefore 0*73 x 2*9/300 = 7*1 
X 10-3 E u. per hour = 20 x lO"*^ E.U. per second. This is the totil 
charge carried ])y all the positive ions, or hy all the negative ions, aet 
free per second. The volume of the bulb being 163 c.c, the charge on 
the positive or negative ions set free per second in each c.c. = 2"0 
X 10-*V163 = 1-2 X 10"^ E.U., and the number of ions of either sign 
set free per second in each c.c. = 1*2 x 10-^6*5 x 10~^® = 19. Tte 
is somewhat grciiter than the number obtained before, but, as w* 
pointed out above, there were sources of error in the older apparatv 
tending to give too low a result for the rate of production of iw* 
per c.c. 



On the lonisation of Atmospluric Air. 159 

Experiments were now made on the variation of the rate of leak 
with pressure. The measurements were made at a temperature of 
about 15' C. Each experiment gave the leakage in a period varying 
from six and a half to twenty-four hours. The silvered glass apparatus 
was used. 

The following results were obtained : — 



Pressure in 
luillimetres. 
43 


Leakage in 
Tolts per hour. 

0-22 


_Leakape 
pressure. 

0052 


89 


0-53 


0-0058 


220 


1-14 


0-0052 


341 


1-59 


0-0047 


533 


2-30 


0-0043 


619 


2.40 


0-0039 


635 


2-65 


0-0042 


731 


2-78 


0-0038 


743 


2-99 


0-0040 



These numbers show that the leakage is approximately proportional 
to the pressure. WTiile the pressure is varied from 43 mm. to 743 mm., 
the ratio of leakage to pressure only varies between 0*0038 and 0058. 
Since the individual measurements of the leakage at a given pressiu-e 
difTered among themselves by as much as 10 per cent., it would hardly 
be safe until more accurate experiments have been performed to 
base any conclusions on the apparent departure from exact propor- 
tionality between leakage and pressure. From these results one would 
infer that it should be impossible to detect any leakage through air 
at really low pressures. This is in agreement with the observations 
of Crookes,* who found that a pair of gold leaves could maintain their 
charge for months in a high vacuum. 

Experiments were now carried out to test whether the contirirous 
production of ions in dust-free air could be explained as being due to 
radiation from sources outside our atmosphere, possibly radiation like 
Kontgen rays or like cathode rays, but of enormously greater penetra- 
ting power. The experiments consisted in first observing the rate 
of leakage through the air in a closed vessel as before, the apparatus 
being then taken into an underground tunnel and the observations 
repeated there. If the ionisation were due to such a cause, we should 
expect to observe a smaller leakage underground on account of absorp- 
tion of the rays by the rocks above the tunnel. 

For these experiments a portable apparatus had to be made (shown 

in fig. 2). It differed from that already described (fig. 1) in the 

:ColIowing respects : — The vessel, of thinly silvered glass as before, was 

inverted and attached directly to the sulphur condenser, its neck 

• * Roy. Soc. Proc.,' rol. 28, p. 347. 1879. 



160 



On the I(ynisation of Ahnaspheric Air, 



being embedded in the sulphur. The electroscope formerly qm 
test the constancy of the potential of the supporting rod was 
pensed with; all need for external wires was thus remoYed. < 
the end of the wire by which the charge was put into the cond 
protruded from the sulphur, and this was covered as shown ii 
figure, except at the moment of charging, by a small bottle oontaj 
calcium chloride ; this fitted tightly on a conical projection oi 

Ffo. 2. 




sulphur, through the centre of which the wire passed. The 
cient constancy of potential of the supporting roil mider these 
ditions was shown by the fact that when it had been put, by n 
of the magnet, in momentary electrical connection with the lea 
system, a second contact, made twenty-four hours later, causec 
gold leaf, which indicated the potential, to return to within two n 
meter scale divisions of its position immediately after the first 
tact. The change in the potential of the leaking system prod 



On the Preparation of Large QtuiiUities of Tellurium. 161 

by such a change in the potential of the support was much too 
small to be detected. 

The experiments with this apparatus were carried out at Peebles. 
The mean rate of leak when the apparatus was in an ordinary 
room amounted to 6*6 divisions of the micrometer scale per hour. 
An experiment made in the Caledonian liailway tunnel near Peebles 
(at night after the traffic had ceased) gave a leakage of 7 divisions 
per hour, the fall of potential amounting to 14 scale divisions in the 
two hours for which the experiment lasted. The difference is well 
within the range of experimental errors. There is thus no evidence 
of any falling off of the rate of production of ions in the vessel, 
although there were many feet of solid rock overhead. 

It is unlikely, therefore, that the ionisation is due to radiation which 
has traversed our atmosphere ; it seems to be, as Geitel concludes, a 
property of the air itself. 

The experiments desciilxjd in this paper were carried out with 
ordinary atmospheric air, which had in most cases been filtered through 
a tightly fitting plug of wool. The air was not dried, and no experi- 
ments have yet been made to determine whether the ionisation depends 
on the amount of moisture in the air. 

It can hardly be doubted that the very few nuclei which can always 
be detected in moist air by the expansion method, provided the expan- 
sion be great enough to catch ions, arc themselves ions merely made 
visible by the expansion, not, as some former experiments seemed to 
suggest, produced by it. The negative results then obtained, in 
attempts to remove the nuclei by a strong electric field, may perhaps 
be explained if we consider that all ions set free in the interval during 
which the supersaturation exceeds the value necessary to make water 
condense upon them, are necessarily caught, so that complete absence 
of drops is not to be expected even with the strongest fields. 

The principal results arrived at in this investigation are (1) that 
ions are continually being produced in atmospheric air (as is proved 
also by Geitel's experiments), and (2) that the number of each kind 
(positively and negatively charged) produced per second in each cubic 
centimetre amounts to about twenty. 



" On the Preparation of Large Quantities of Tellurium." By 
Edward Mattiiey, A.K.S.M. Communicated by Sir George 
Stokes, Bart., F.ILS. Received February 19, — Read March 
14, 1901. 

For several years I have worked upon bismuth ores of varying 
richness for the extraction of the bismuth they contain, and I have 



162 071 tJie Preparation of Large Quantiiies of Tellurium. 

already communicated the results to the Boyal Society.* Many, if 
not most of these ores, contained traces of tellurium. 

Teliuriiun has a marked tendency to associate itself with hismuth, 
as silver may be said to do with lead, or phosphorus with iron, and 
accordingly the crude bismuth extracted from these ores invariably 
contained small quantities of tellurium, which was reduced together 
with the l)ismuth, and was found to exist in it in a greater proportion 
than in the ores. 

The presence of even minute traces of tellurium in bismuth being 
sufficient to render this metal unsaleable, it is necessary to remove 
every portion of the tellurium whilst refining the crude bismuth. The 
alkalies containing the tellurium resulting from the refining of the 
crude bismuth were thrown aside, and were left for future investigation. 

I have now l>cen able to treat these alkaline residues, and have ex- 
tracted from them a substantial amount of metallic tellurium, weighing 
26 kilos. This amount of tellurium was produced from 321 tons d 
mineral containing an average amount of 22*50 per cent, of bismuth. 

The amount of metallic tellurium obtained corresponds to an average 
of 007 per cent, of the original mineral. 

The 26 kilos, of metallic tellurium was obtained by soaking the 
telluridc alkalies, resulting from refining the telluric bismuth, in hot 
water — acidifying these solutions with hydrochloric acid, and preci- 
pitating the telluiium with sodium sulphite. A crude mixture of 
bismuth and tellurium was thus obtained, the tellurium forming about 
47*5 per cent, of the crude metal. 

This was dissolved in nitric acid, and again treated in the same way, 
and yielded the amount of tellurium represented by the 26 kilos. This 
shows on analysis : — 

Tellurium 97'00 

Bismuth 2-15 

Copper 0"65 

Iron 010 

Loss 0-10 



100-00 



The appearance of the metal when broken shows a crystalline fra^ 
ture, of needle-like structure, and of bright metillic lustre. It dofli 
not readily tarnish in the air at the ordinary temperature. If slowlf 
cooled, a crystalline form very much resembling that of bismuth ii 
obtained. 

Its specific gravity is 6*27, as against 6*23 the density of uncoo- 
pressed tellurium found by Spring. 

• ' Roy. Soc. Proc.,* vol. 42, 1887, p. 89; toI. 49, 1890, p. 78 ; and rol. 62, WW, 
p. 467. 






w 

% 



Tfnnamisaion of the Trypanosoma Evansi h/ Horse FlUft, 16;> 

The temperature of solidification was determined by means of the 
Le Chatelier pyrometer, and proved to be 450* C, or 5" lower than 
that given by Carnelly and Williams.* 

Some tellurium prepared from this 26 kilos, to chemical purity also 
gave 450' C. as the solidifying point. 

Commercial telhuium obtained from Germany proved to have the 
same melting point and specific gravity as my own tellurium. 

I foimd the electrical resistance to be about 800 times that of copper. 
The resistance, however, appears to be very greatly dependent on the 
crystalline conditions. 

A rod cast and cooled quickly has a lower resistance than one that 
has been cooled slowly. A current of a few amperes will quickly raise 
the temperature of a rod 0*2 inch in diameter. In casting small rods 
of tellurium, of say § inch diameter, there is much contraction, and 
partial separation takes place even after some hours. 

The thermo-electric power of tellurium appears to be great. 

It has been a source of great satisfaction- to me, as a metallurgist, 
to produce so large an amount of tellurium from a mineral in which it 
existed only in minute traces. The amount of 57^ 11). (26 kilos.) of 
tellurium was derived from 187,019 lbs. of crude bismuth, which 
resulted from the treatment of 831,168 lbs. of mineral. 



** The Transmission of the Trypanosoma Evaiisi by Horse Flies, 
and other Experiments pointing to the Probable Identity of 
Surra of India and Xagana or Tsetse-fly Disease of Africa." 
By Leoxakd Eogers, M.D., M.R.C.P., Indian Medical Service. 
Communicated by Major D. Bruce, R.A.M.C., F.R.S. lic- 
ceived January 28, — Read February 14, 190.1. 

(Communicated to tho Tsetse-fly Committee of the Rojal Soeiet j.) 

The close resemblance between siu*ja of India and tsetse-fly disease 
^>f Africa has long been known, while Koch, after having seen the 
^living Trypanosoma Evansi at Muktesar in India, and soon after 
> ^rtndied the parallel disease in German East Africa, pronounces them 
'f^ifeo be the same, and in his * lieisel)erichte * calls the disease seen in the 
3fc^tter place " Siwrakrankheit." The appearance of the report made to 
pKfce Tsetse-fly Committee of the Royal Society by Kanthack, Durham, 
"r^Jtid Blandford on their experimental investigation of the latter disease, 
to me to repeat some of their experiments in the case of 

• * Chem. Soc. Jouni.,* toI. 37, p. 125. 



164 Dr. L. Rogers. Tlie Traiis^nission of the 

urra, with a view to contributing towards the solution of the question 
of the identity or otherwise of the two diseases, and the following is a 
brief account of the results obtained while I was in charge of the 
Imperial Bacteriological Laboratory at Muktesar, during the absence of 
Dr. Lingard on sick leave. 

I. The Traiisnimion of Surra hy the Bites of Hoi'se Flies. 

It was proved some years ago by Bruce that the Trypanosoma Brucei 
is carried from one animal to another by the bites of the tsetse fly. 
As siu'ra can be certainly produced in susceptible aninuds by the 
application of infected blood to the smallest scratch in the skin of 
another susceptible animal, it appeared to be likely that horse flies 
might carry the infection from one animal to another. A series of 
experiments were carried out to test this possibility with the following 
results. Horse flies were caught and kept for varying periods of time 
after having been alio wad to bite and suck the blood of an animal 
which was suffering from surra, and whose blood at the time contained 
the Trypanosoma Evansi in considerable or large numbers. They were 
subsequently allowed to bite a healthy animal, dogs and rabbits being 
used in the experiments, and the former were kept in a different 
house at some distance from the infected animals, and the latter in 
separate cages during the incubation period. In every case in which 
the flies had been kept from one to foiu* or more days after biting the 
infected animals, no disease ensued in the healthy ones. Many such 
flies were dissected and microscopically examined, but in no case was 
anything which might be taken for a development of the trypanosoma 
in the tissues of the insect detected. A rat was also fed on a number 
of flies, which had bitten infected animals at varying periods pre- 
viously, but no infection was thus produced. 

AVhen, however, flies which had just sucked infected blood were 
immediately allowed to bite another healthy animal, positive results 
were obtained after an incubation period corresponding with that of 
the disease produced when a minimal dose of infected blood is inocu- 
lated into an animal of the same species. The result was uncertiiin if 
only one or two flies were allowed to bite, and especially if they were 
allowed to suck as much blood as they wished without being disturbed. 
If, on the other hand, several flies, which had just sucked an infected 
animal, were induced to ])ite a healthy one, and especially if they were 
disturbed and allowed to bite again several times, infection was always 
readily produced in both rabl)its and dogs, the fur of the latter having 
been carefidly cut, withoiit abrading the skin, at the site over which 
the flies were applied. The following is the chart of a typical experi- 
ment of this kind. The dog was lutten by twelve flies which had just 
previously sucked blood from a dog, which was swarming with the 



Trypanosoma Evansi by Horse Flics, 



165 



Trypanosoma Evansi^ and which had itself been previously infected by 
the bites of flies experimentally. On the seventh day the organisms 
were found in the blood in small numbers, and steadily increased 
during the next two days to swarming — that is, over fifty in the field 
of a Zeiss D lens, and after oscillations the animal died on the tenth 
day after the appearance of the organisms in the blood. Post-mortem 
the usual lesions were found, the spleen being very much enlarged. 
The right axillary glands were much enlarged, and contained the 
organisms, while those of the left axilla were but half the size of those 



Chart of dog infected by the bites of horse flies which had just 
previously bitten a surra dog. 



^f ^d/flsm s. 




Swdrmif^. 



nymemm. 



Nutmmis. 



DoUedUne - TempenaMure Curve, 
Continued Line'' Curve of number of orgAniants 
in Che blood 

of the right side, which is of importance in connection with the fact 
that the flies had been applied to the upper part of the right side of 
the body within the area whose lymphatics pass to the right axillary 
glands. The glands of the right groin were also larger than those of 
the left, and also contained the organisms in large numbers. 

Unfortunately these experiments could not he extended to horses 
on account of the necessary flies only being found at the height of the 
Muktesar Laboratory (7800 feet above sea level) during the three or 
four hottest months, and they were not available in the rainy season 
when a horse had been obtained for the experiment. The skin of this 
animal, however, is so thin that it would be likely to be at least as 
easily infected as a dog, while the facts above recorded will readily 



166 Dr. L. Rogers. 3f%€ Transmission of the 

explain the slow and irregular spread of surra through a stable of horses, 
by the occasional occurrence of the event of a fly which has bitten a 
diseased animal being disturbed and immediately going off to bite 
another healthy one. Further, the proof that infection may take place 
through flies, brings surra into closer resemblance to tsetse-fly disease, 
and increases the probability of the two being identical, or, at least, 
caused by very closely allied species of the same family of parasite. 

II. Latent Cases of Surra in Cattle as a Possible Source of Infection, 

Bruce has shown that the parasite of tsetse-fly disease may be 
present in the blood of big game animals without causing acute 
symptoms or definite sign of disease, and that their blood when 
inoculated into susceptible animals will produce the typical acute 
affection ; and further that a very protracted form of the disease may 
occur in sheep and goats, and possibly form a source of infection for 
animals. Lingard, in his first volume on "Surra," records the case 
of a bull which he inoculated with surra, and in whose blood the 
trypanosoma was found for three days only, shortly afterwards, yet 
guinea-pigs inoculated with the blood of this bull on the 85th and 
163rd days after the first appearance of the parasite developed fatiil 
siura with numerous trypanosoma in their l>lood. Further inocula- 
tions from the bull on the 234th and 267th day proved negative. He 
has also recorded two naturally acquired cases of the surra in cattle, 
which proved fatal. These facts suggest the possibility of the latent 
disease in cattle acting as a source from which ])iting flies might carry 
the disease to horses, especially as surra is so frequently met with on 
the roads to hill stations in India, where numbers of bullock carts arc 
going up and down. It seemed advisable, therefore, to repeat this 
observation on surra in cattle, so I inoculated a small hill bull intra- 
venously with a small quantity of blood from a rabbit, which contained 
numerous trypanosoma. Tlie result confirmed Dr. Lingard's observa- 
tion, for on the seventh day after inoculation the organism appeared in 
small numbers in the blood of the bull, remained present for four days, 
and subsequently was not detected during the next 161 days of the 
disciise, while the animal, after showing slight signs of illness for about 
a month, remained subsequently in apparently good health, except for 
an occasional slight rise of temperatiu'e for two or three days, A rat, 
which was inoculated on the 30th day of the disease, and two rabbits 
inoculated on the 59th and 141st days respectively, developed fatal 
surra, with large numbers of the trypanosoma in their blood ; that on 
the latest-mentioned date having been done during a temporary rise of 
temperature of the bull without the presence of any trypanosoma.* 

• AU the rats used in experimentg mentioned in this paper had been first proved 
to be free from the Trjfpanotoma tanguinU^ except where otherwise stated. 



Trypanosoma Evansi hy Horse Flics, 167 

However, the incubation period was an unusually long one, namely, 
fifteen days, against from four to six days in the case of rabbits inocu- 
lated with the blood of a surra animal which contained the trypanosoma. 
My observations on intermediate developmental forms of the trypano- 
soma are not sufficiently advanced for any definite statement on the 
forms present in the bull's blood at the time these inoculations were 
made. 

A very similar result was obtained in the case of a sheep, in which 
the trypanosoma appeared seven days after inoculation with the blood 
of a surra dog, remained present for six days in small numbers, and 
was then absent for thirty days, during which the animal showed 
definite sjrmptoms of somewhat mild surra, but improved somewhat 
latterly. At this period it was handed over to Dr. Lingard, on his 
resuming charge of the Muktesar Laboratory, and I am unable to give 
the final result as he has not acceded to my request for information 
on the point. A goat inoculated at the same time showed the surra 
organism in its blood on the fourth day, and continued to show it at 
intervals up to the twenty-sixth day, after which it was absent for the 
remaining thirteen days that it was under my observation ; but this 
animal was much more ill than the sheep, and became greatly wasted, 
and presented oedematous swellings on the legs, enlargement of the 
lymphatic glands, yellow marks on the conjunctiva, and nasal discharge. 
Lingard also records one case in a sheep which was fatal after 127 days, 
and three experiments on goats in which the disease was fatal on from 
the 58th to the 186th day. 

In all three animals, then, surra tends to run a prolonged and 
chronic course, and especially in the case of cattle and sheep ; in the latter 
of which surra affords an additional point of resemblance with tsetse of 
Africa. It has been thought by some that the difference in the course 
of the two diseases in the case of cattle is a strong argument against 
surra and tsetse-fly disease being identical, as the latter is a much more 
fatal disease in these animals than surra is in India. The difference, 
however, is but one of degree, for cattle in South Africa not imfre- 
quently do recover from the disease of that country, while surra may 
be fatal to cattle in India, and may, indeed, prove to be much more 
frequently so than is at present imagined, when diseases of cattle are 
more closely studied in India than they have as yet been. Further, 
Koch has recently shown that the disease in German East Africa is 
absolutely fatal to the ordinary breeds of donkeys in that country, 
yet the Masai donkeys are absolutely immune. This shows a difference 
of susceptibility between different breeds of the same animal to the 
same (African) disease, much greater than that existing between two 
breeds of cattle in South Africa and India respectively towards the 
two diseases nagana and surra. Hence this argument against the 
identity of the two affections loses much, if not all, its weight. Th^ 



168 Dr. L. Rogers. Tlu Transmission of the 

possibility of latent forms of surra in cattle, and poflsibly also in sheep 
and goats, in India taking the place of similar infections in wiM 
game in the case of tsetse-fly disease in South Africa is, then, worthr 
of consideration, and the two may be closely analogous. 

III. Feeding Ej-perinienis. 

Kanthack, Durham, and Blandford record that they were unsucceo- 
f ul in most of their experiments in producing infection of Nagana, by 
feeding animals on mateiial containing the organism of the disease, 
the possibility of infection appearing to depend on accidental lesioK 
of the nose and mouth, tl'c. Lingard, on the contrarj', records in his 
iirst volume on " Surra " one negative result in a horse after the ingw- 
lion of 200 CO. of infected blood, and one positive one 75 days after 
the last, and 130 after the first, tlose of .blood by the mouth, smiB 
(luantitics of material being given at frequent intervals. As he w» 
working in an infected district, and the incubation period was ib 
extraordinarily long one, this experiment can hardly be accepted aJ 
conclusive, especially in view of the proof given above, that thf 
disease can be carried by flies. That spontaneous infection did occur 
in some way in the course of his exj)enments is clear from the ca» 
which he record.-?, in which a horse, which was being given large dois 
of arsenic as a ])rophylactic measme, spontaneously developed the 
disease before he was inoculated, very possibly through infection I? 
fiies from sonu^ other animal under experiment. This possible soortf 
of fallacy is excluded in the few experiments I have canied out ontiis 
point, ])y the fact that they were performed at a time of the year whs 
there were no ])iting flies to be foiuid. With the exception of o« 
rabbit, which was fed on i c.c. of surra blood swarming with tk 
organism, in 10 c.c. of milk, with a negative result, rats were used ii 
these experiments, either some organ of an animal dead of surra, cf 
the bloo<l of the same in milk being given. At first the result, 
although usually negative, were not always so, as in the case d 
Kanthack's experiments. A j>ossi))le soiu^ce of infection was found ii 
the fact that some of the animals had previously been examined ta 
the Tnjintno!>ornn sunujuinu the same morning as the feeding experi- 
ment was carried out, and one of the animals was observed to hck th 
wound in its tail in the intervals of feeding on the infected materii 
This source of infection was then carefully excluded, and seveni 
experiments were done in which a little surra blood in milk was givei 
to two rats, one of which was untouched, while in the case of th' 
other the nose and mouth Avere first al)raded. In each case tb 
untouched rat escaped infection, while the one with abrasions eet* 
tract ed fatal surra after the usual incubation period for the inoeulatrf 
disease. These experiments, then, support the view that infection 
the case of feeding is through some lesion in the skin or mucor^ 



I 



Tiypanosoma Evansi hy Hoi^sc Flies. 169 

membranes, and once more the results obtained in the case of surra 
are precisely similar to those got in the researches on tsetse-fly disease 
conducted under the Committee of the Royal Society. 

IV. Is the Trypanosoma sanguinis related to Surra ? 

It is pretty generally agreed that the Tri/panosonm sanguinis of rats 
is distinct, both morphologically and pathologically, from nagana and 
surra, although in the case of the latter disease Dr. Lingard claims to 
have produced surra in horses and other animals by inoculating this 
organism. The incubation period, however, in his four successful 
out of twelve experiments in horses, varied between 7 and 65 days, 
although on the next passage it returned at once to the ordinary 
period for surra of about 7 days. This remarkable fact, taken in 
conjunction with his having worked in an infected area, and with 
the proof of the possibility of flies carrying the disease, makes it 
possible that the infection was produced by some other agency than 
the rat's parasites. I recently inoculated a pony intravenously ^Wth 
2 c.c. of the blood of a rat infected with the Trypanosoma sanguinis^ 
with a negative resuJt during the 55 days it was under my observa- 
tion, the blood being examined daily, the experiment having being 
carried out at a time of the year when no biting flies were to be 
found, and in a non-endemic area. It may thus be worthy of record 
in this connection, as although but an isolated one, it is in agree- 
ment with the results of Vandyke later. 

Another pony inoculated with a few drops of the blood of a surra 
dog five days after the one just mentioned, developed surra on the 
ninth day, as shown by the presence of the Trypanosoma Evansi in its 
blood. A negative result was also obtained in the case of a dog 
which was twice inoculated with the Trypanosama sanguinis and 
examined daily for 82 days. 

Rats, which had been found to harbour the Trypanosoma sanguinis, 
were also inoculated with siu-ra, and after the usual incubation period 
in these animals of about four days the Trypanosama Evansi appeared 
in the blood, and were easily distinguished from the former parasite 
by their much shorter and blunter ends. They increased daily until 
in most of the cases over 50 were present in a field of a Zeiss D lens, 
while the original rat organisms remained at about the same numbers 
as before the inoculation with the surra blood. The two organisms, 
therefore, appear to me to be quite distinct both morphologically and 
pathologically. 

In every point, then, that I have so far investigated, the results 
obtained in the case of surra closely agree with those of the Royal 
Society's Committee in tsetse-fly disease, and so far as they go they 
support the view that the two diseases are probably identical. I \i^^ 



170 Tmmmis8ionofth^Tj'paiioBoma'E\a,u&ihfHor$eIlia, 

hoped to have been able to make arrangements for studying bolli 
diseases side by side, but have not yet been able to do so on seconnt 
of the disturbed state of South Africa. 



3farch 21, 1901. 
Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, in the Cbir. 

A List of the Presents received was laid on the table, and thanb 
ordered for them. 

The Croonian Lecture, " Studies in Visual Sensation," was deliTend 
by Professor C. Lloyd Morgan, F.R.S, 



March 28, 1901. 
Mr. TEALL, F.G.S., Vice-President, in the Chair. 

A List of the Presents received was laid on the table, and thtfb 
ordered for them. 

The following Papers were read: — 

I. "On the Arc Spectrum of Vanadium." By Sir N. LoCKTft^ 
F.R.S., and F. E. Baxaxdall. 

II. " On the Enhanced Lines in the Spectrum of the Chromosphere.*] 
By Sir X. Lockykr, F.R.S., and F. E. Baxandall. 

III. " Further 0])servations on Xova Persei, No. 2." By Sir 1 

LOCKYER, F.R.S. 

IV. " The Growth of Magnetism in Iron imder Alternating Ma^ 

Force." By Professor Ernest Wilson. CommWicated 
Professor J. :M. Thomson, F.R.S. 

V. " On the Electrical Conductivity of Air and Salt Vapours." 
Dr. II. A. AViLSON. Communicated by Professor J. J. ' 
SON, F.RS. 



The Society adjourned over the Easter Recess to Thursday, Mif J 



On the Besults of Chilling Copper-Tin Alloys, 171 

"On the Besults of Chilling Copper-Tin Alloys." By C. T. 
HErcocK, F.RS., and F. H. Neville, F.RS. Eeceived 
rebniary 12,— Bead February 28, 1901. 

(Plates 2-3.) 

In the Third Eeport of the Alloys Besearch Committee, published 
in 1895, Sir W. Boberts- Austen gives an appendix, by Dr. Stansfield, 
containing an extremely interesting series of cooling curves of the 
copper-tin alloys. These curves made it evident that for many per- 
centage compositions there were three or even four halts in the cooling 
due to separate evolutions of heat, and that some of these changes must 
have occurred when the metal was solid. A freezing-point curve was 
also deduced from the cooling curves. The report contained interest- 
ing remarks on the meaning of the curves, but a satisfactory explana- 
tion was not at that time possible. In June, 1895, Professor H. Le 
Chatelier also published a freezing-point curve, giving the upper points 
only. These two curves agree in locating a singular point near the 
composition CoiSn, but do not give any singular point nearer to the 
copper end of the curve. 

In 1897 we also gave, in the * Philosophical Transactions,' a freez- 
ing-point curve of these alloys. This curve was inferior to Dr. Stans- 
field's, inasmuch as it gave no information concerning the changes 
that go on in the solid metal, but it was a more accurate statement 
of the upper freezing points than had been given before. In particu- 
lar, it pointed out a now singular point at 15*5 atomic per cents, of 
tin, the point marked C in the figure (fig. 1), and a straight branch of the 
curve joining C to the other singular point marked D in the figure* 
Both C and D are the origins of rows of second isothermal freezing 
points, better called transformation points. Like Dr. Stansfield, we 
foimd it impossible to offer a satisfactory explanation to the curve, 
but we hazarded the surmise that the steepness of the branch ABC 
might be due to chemical combination, and that in the region CDE 
solid solutions existed. Both of these surmises have since been con- 
firmed, but at that time we felt no certainty on the subject. 

In their report on alloys presented to the Congres International de 
Physique in 1900, Sir W. Boberts-Austen and Dr. Stansfield give a 
curve embodying all the above-mentioned details and some others, in 
particular a most important lower curve of changes that take place in 
the solid alloys.* 

Our attention has been caUed to tbe fact that the copprr-tin curve giyen 
by Robertii. Austen and Stansfield in the International Keport on Phjaics in 
19O0 had already been publUhed by them in the Fourth Report to the AII039 
Beaearch Committee in 1897. This correction does not alter the chronological 
•oq^ence as stated in the text, since our paper waa read before the Royal Society 
m June 1S96. » f r- j j 

VOL. LXVIII. 



172 



Messrs. C. T. Heycock and F. H. Neville 



It loay be i*eniarked that the freezing-point curye fomia a i 
chart to the general character of the alloys. For e x amp le , i 
whose composition lies in the region AB of the figure are red br 
and gun metals, tough, but not very hard, while as we appra 
the alloys become palor in colour and much harder. Alloys a lit 
the left of C are nearly white and extremely tough and strong; 
are ideal bell metals. The moment we pass C the alloys begi 
become brittle, and the brittleness becomes very great near D. 
alloys between C and D are steel coloured ; they have a ^m 




Fig. 1. — Froezing-point curve of the copper-tin alloys. Atomic percentage! 
are reckoned from per cent, on left to 100 per cent, on right of dii 
(Extracted from ' Phil. Trans.,' A, toI 189, p. 63.) 



hardness and take a fine polish ; they are speculum metals, Lord B 
being the alloy at D. With more tin than that present at the po 
the alloys deteriorate from a mechanical point of view, and exc< 
anti-friction metals are not much used. 

In 1900 wc commenced a study of these alloys by means o 
microscope. As regards the regions ABC and that to the right 
we at first did little more than confirm results which we foani 
been already published both by Mr. Stead and by M. Charpy; 1 
the region CDE we appear to have observed more detail than ii 
tained in the published work of these observers. We were espe 
struck by a discrepancy, in the region CD, between the crysta 
the outside of the alloys and the internal pattern. Our habit i 



On the BestUts of Chilling Copper-Tin Alloys. 173 

make the alloys in an atmosphere of coal-gas or hydrogen, and to 
allow them to cool in this atmosphere. If made in this way, we found 
that all alloys, from A almost to D, showed on the top of the ingot a 
regular crystallisation in relief, of the rectangular comb-like character 
so often seen on the surface of cast metal. This was as perfect in the 
white metals between C and D as in the red alloys between A and B. 
lliese crystals disappear when the point D is reached, although with 
much more tin other types of raised crystals are seen. These combs 
are of course primary crystals, standing out on account of the con- 
traction of the solidifying mass and the consequent retirement of the 
mother liquid. When the ingots of alloy are cut, the surfaces polished, 
and the internal pattern brought out by ignition or etching, one sees, 
as Charpy and Stead have shown, that similar combs, rich in copper, 
occur in the interior of the ABC alloys, the combs being embedded in 
a matrix which is itself complex (see photo. 1, PI. 2). These combs are 
numerous and large in the gim-metals of the region AB, but decrease 
in numbers, size, and perfection as we approach C. For some distance 
to the left of C they are much broken and distorted, and to the right 
of C they do not appear at all in the body of the alloys ; but they 
exist on the outside in the same perfection as before. Moreover, if 
the top of one of the alloys anywhere between a point a little to the 
left of C and the point D be slightly ground down so as to obtain 
sections half through the raised crystals, and the pattern examined, it 
is found that the crystals are not homogeneous, as one would expect a 
crystal to be, but that each crystal is full of a well-marked pattern 
identical with that of the body of the alloy. To illustrate this pecu- 
liarity, we give a photograph of the top of the alloy containing 14 
atomic per cents, of tin (photo. 2). Hence it appeared that the alloys 
underwent remarkable changes both during and after solidification. 
In the alloy of photograph (2) the larger detail in the substance of the 
bars of raised crystal, or something not unlike it, was formed before 
the raised pattern, but the smaller detail, hardly seen at this magnifi- 
cation, is more recent than the raised pattern. 

Photograph (1) shows the large primary combs existing in the 
interior of an alloy containing 12 atomic per cents, of tin, and photo- 
graph (3) shows the utterly different pattern existing on the other 
side of C. It is that of an alloy containing 16*7 atomic per cents, of 
tin. It must be remembered that on the outside the alloy still shows 
the combs. These alloys were slowly cooled, "that is, not subjected to 
any sudden chill during cooling. A pattern like that of photograph 
(3) is given by Charpy for an alloy containing equal weights of copper 
and zinc. We have also found it in some silver-zinc alloys, and we 
think it always means that changes have taken place in the solid 

alloy. 

The patterns at all points on the curve were so puzzling that we 



174 



MoBsrs. C. T. Hejcock and F. H. Neville. 



almost despaired of being able to interpret them, until after reading 
Professor Roozeboom's paper on the " Solidification of Mixed Crystals 
of Two Bodies/ published in the 'Zeitschrift fur Physikalische 
Chemie' of December, 1899. The beautiful theory contained in this 
paper made the attempt to decipher the hieroglyphic of the copper-tin 
alloys more promising; but the experimental method recommended 
by Roozeboom, that of isolating the first crystals that form when a 
liquid begins to solidify, is beset with almost insuperable difficulties in 
the case of metals melting at high temperatures. Cooling curves will, 
it is true, give the approximate moment of complete solidification of 
an alloy, and enable us to plot in a rough way the *' solidus " curve, 
as Roozeboom calls it ; but the solidus curve thus obtained is not 
nearly so accurate as the "liquidus" or freezing-point curve. We 
therefore had recourse to the microscopic examination of chilled 
alloys, a method which has thrown so much light on the nature of 
steel. 




Fig. 2.— Cooling curve of the alloy CugiSnig. Percentages by weight: Cu 69'50\ 
Sn 30*44-. Time is measured horizontally. Equal verti(.*al distances correspond 
to equal difPerences in platinum temperatures. Tlic numbers at sides of 
diagram give temperatures on the Centigrade scale. Tho numbers on the 
curve are the points of chilling. 



The first step was to imitate Austen and Stansfield and obtain a 
cooling curve of an alloy by means of a recording instrument. We 
used a Callendar recorder in connection with a platinum pyrometer. 
Fig. 2 is a small scale reproduction of the cooling curve thu.s 
obtained in the case of an alloy containing 19 atomic per cents, of tin. 
In this curve the temperature of the cooling alloy is measured verti- 
cally, and the time is measured horizontally. It will be seen that 
evolutions of heat occur during the period MNO and also at P and Q. 
Below the temperature O the alloy was a rigid mass, a solid. The 
temperatures marked 1, 2, 3, 3a, 4, 5 on the curve were then selected 
as points at which it seemed well to chill portions of the alloy. The 
pyrometer was therefore transferred to a bath of molten tin, heated 
well above the highest freezing-point of the alloy, and small amounts 



On the ResvlU ofChiUing Copper-Tin Alloys. 175 

of from 5 to 10 grammes of the alloy, contained in little test-tubes of 
Jena glass, were immersed in the bath ; these were in an atmosphere 
of coal-gas, and so did not oxidise. The bath of tin was then allowed 
to cool slowly and uniformly, and when the temperature fell to one of 
the selected points, a tube was taken out and plunged into water. 
The alloy was thus chilled, the slow cooling being brought to an 
abrupt end at any desired temperature. 

The chilled alloys were afterwards ground down and polished in the 
usual way. After the trial of many reagents for bringing out pattern, 
we adopted the method of slightly heating the surface until the film 
of oxide formed was of a pale yellow colour. Behrens some years 
ago recommended this method, and Mr. Stead has pointed out that 
it develops differences of chemical composition very well, while 
etching reagents complicate the picture by revealing the orientation 
of crystals and other details which are not always needed. With 
one or two doubtful exceptions, we find that in alloys richer in 
copper than CusSn, the parts which oxidise most rapidly, and are 
therefore darkest in the yellow stage, are the softer parts contain- 
ing most copper. Wlien alloys on the branch ABC are oxidised the 
pattern is very distinct to the eye, but it is sometimes diflScult to 
obtain much contrast in the photographs ; in such cases (for example, 
in the alloy of photograph 1) we etched the surface witl\ strong 
ammonia, which also darkens the parts richest in copper. Alloys on 
the branch ABC are very sensitive to reagents such as ammonia or 
hydrochloric acid, and from C to D, where these have but little 
action, a mixture of hydrochloric acid and potassium chlorate etches 
rapidly. One can use these reagents to control the effect of heat 
oxidation in cases where the low temperature of chilling makes it 
possible that the heating needed to produce the yellow colour may 
have reversed the result of chilling; but we find that there is not 
much danger of such a reversal. 

The upper point alloy, chilled at the commencement of solidification, 
was generally found to be granulated by the operation of dropping 
into water, but portions could always be found suitable for polish- 
ing; the other alloys had always solidified before the chilling, and 
therefore gave compact ingots. 

After polishing, the alloys were heated until a pale yellow oxidation 
colour was produced on the surface. 

Alloy (1), chilled when much of the metal was still liquid, shows a 
pattern of large primary skeletons, more or less comb-like in appear- 
ance, which oxidise much more rapidly than the mother substance, 
and which therefore contain more copper than it (photo. 4). 

Alloy (2), chilled when the solidification was almost complete, shows 
skeletons much softer in outline and not differing much in oxidation 
colour from the ground ; but these skeletons occupy ^ \s^^ W^^ 



176 Messrs. C. T. Heycock and F. H. Neville. 

area than in (1), nearly filling the field, and being only separated 
from each other by an imperfect network of less oxidised mother 
substance. 

These two alloys are deeply etched in the process of polishing with 
rouge, the softer primaries rich in copper being eaten away. The 
pattern is so large that it is best examined with a power of 10 or 
20 diameters. 

In striking contrast to the above, alloys (3) and (3) A, chilled when 
the alloy has been solid some time, show no pattern even with a power 
of 300 or 400 diameters (photo. 5). 

Alloy (4), chilled at P, the next point of heat evolution on the cool- 
ing curve, shows a pattern which is a close approximation to that of a 
slowly cooled alloy, and alloy (5), chilled at a still lower temperature, 
is an almost perfect reproduction of the slow-cooled pattern (photo. 6). 
It will be noticed, however, that a little below the chilling point of 
(5) there is another stage of heat evolution, and in harmony with this 
we can find one point of diflterence between the pattern of (5) and that 
of the slowly cooled alloys of the region CD. Both in these and in (6) 
the surface is divided into large polygons bounded by bands of a 
smooth material, and the interior of each polygon is more or less 
full of a broken fern or flower-like crystallisation of the same smooth 
body as that of the bands. The ground in which the fern leaf lies is 
more easily oxidised than the material of the fern leaf and bands, so 
that the ground probably has more copper in it. In the slowly cooled 
alloys near C there is very little of the fern leaf, but as we approach D 
it increases in amount until at D it almost fills the whole area, not 
absolutely, however, for a network of the darker ground can still be 
traced here and there. A comparison of photos 3 and 6 illustrates 
this growth of the fern leaf with the increase in the percentage of tin. 
In the slow-cooled alloys the ground is granular — in fact, an immersion 
lens defines it as a well-marked eutectic. In (5), on the contrary, the 
ground appears to be uniform ; probably chilling at a temperature 
below Q would convert it into the eutectic. 

All the alloys from a little to the left of C to ])eyond I) exhibit 
similar contrasts between the chilled and slow-cooled patterns, there 
being for each alloy a region of temperature such that if it be chilled 
in this region it shows no pattern. Alloys between D and E are still 
more remarkable when chilled. 

If we apply Roozeboom's theory to these results, we see that in the 
cooling curve the branch LM corresponds, as is obvious, to the cool- 
ing of a liquid, and the short branch MN to the formation of mixed 
crystals separating out of a liquid that is continually growing richer 
in tin, so that the crystals are suffering transformation. The branch 
NO, almost flat at first, and then only slightly sloping, corresponds 
\o an isothermal transformation of the mixed crystals followed by 



yf" 



DESCRIPTION OF PLATE 2. 

Slowly cooled alloys. 



Percentaj;e 
Formula, by weight. 

1 r„ s« ft3ii=7J)-7. 



2. Cu^Sni, ^g^ ^ 23-3. 

8. ^'tw,Sn,«.-{l^*I.]^;^; 300 



Magnification. 
60 diameters. 

50 



Treatments 
Ammonia etch. 

Heat^zi^HML 



SYCOCK & Neville. 



Roy. Soc, Proc, VoL 68, PL 2, 




I 



DESCRIPTION OP PLATE 3. 
The same alloy chilled at different temperatures. 

IVrcenlnjjr 

Forniulti hy woi^xht. Magnification. Treatment. 

4. Cu„iSni3 1 1^^'^' 2 :^o-.i }^'^"" ^' ^^ clianicters. Heat-oxidised. 

5. „ .. Chill 3. 50 

0. „ „ Chill 5. 50 „ „ „ 



EYCOCK & NeVILLK. 



Roy. Soc. Proc, Vol. 68, PI. j. 




On th€ Besviis of Chilling Copper-Tin Alloys. 177 

the solidification of the whole mass to mixed crjrstals, which, assu- 
ming no lag in the transformations, should be uniform. The long 
slope OP would then correspond to the cooling of a solid mass of 
uniform crystals, and therefore the alloys chilled in this region of 
temperature show no pattern. But at P the solid solution becomes 
saturated, and on cooling below this point the band and fern leaf crys- 
tallises out. At a still lower temperature, probably Q, the mother 
substance of the fern leaf breaks up into a eutectic, formed in the 
solid. We think that P is a point on Austen and Stansfield's lower 
curve, and that Q is the eutectic angle of that curve. It will probably 
be found that the mother substance in all alloys from about 6 to D 
breaks up into a complex when the alloys cool to the temperature Q, 
so that if cooled slowly it is a eutectic, but if chilled above Q a 
homogeneous body. 

It is not difficult to form a conception of how the type of pattern 
found below the temperature P originates. Slightly above the tem- 
perature the alloy consisted of crystal grains surrounded by mother 
liquid somewhat richer in tin. At the moment of complete solidifica- 
tion the grains should have adjusted themselves so as to be identical 
throughout, but it is improbable that so perfect an equilibrium was 
attained, and the solid mass at temperatures below must have con- 
tained nuclei richer in copper than the material surrounding them. 
In fact, prolonged polishing brings out a vagiie pattern in relief, 
showing differences of hardness, and therefore of composition. Now 
the alloy that we are considering lies to the right of Austen and 
Stansfield's eutectic angle in their lower curve ; hence when the solid 
solution became saturated the new crystallisation commenced in the 
interspaces rich in tin, and more or less took their form. It is clear 
that the resulting structure would in section give the bands and poly- 
gons of the slow-cooled alloys. Similarly the inclusions of mother 
substance in the grains existing at would be the origin of the isolated 
fern leaf. 

Although it was hardly necessary, we thought it would be interest- 
ing to arrive at the condition of no pattern, starting from the solid 
alloy instead of from the liquid. We therefore took a fragment from 
an ingot of the same slowly cooled alloy, heated it to a faint red heat 
in the Bunsen flame, and dropped it into water. It showed no pattern 
after being polished and ignited to a pale orange. It was then heated 
to a temperature a little below redness, and allowed to cool for five 
minutes above the flame, repolished, and brought to the orange state. 
It then showed a very perfect slow-cooled pattern, the fern leaf being 
particularly good. The polygons appeared to be of the same size as in 
the original alloy, which had taken an hour or more to cool, but the 
bands were much thinner and the fern leaf smaller ; the eutectic also 
was very scanty, while in the original ingot there wex^ W^'a ^-^d^^^ <A 



178 Sir Norman Lockyer and Mr. F. £. Baxandall. 

it. Thus the same alloy, without being melted, can by heating and 
chilling have all pattern removed, and by reheating, followed by a 
not very rapid cool, the pattern can be restored. The constancy in the 
size of the polygons points to their having been formed at an earlier 
period in the history of the alloy. 

We see from the above that the patterns of slowly cooled copper-tin 
alloys are, at all events until they have been confirmed by the examina- 
tion of chilled portions, entirely misleading as to the separations that 
occurred during solidification. Even the evidence for the existence of 
the compound CusSn will have to be revised ; although in a somewhat 
altered form it will probably be found to be satisfactory. 

We hope shortly to present to the Royal Society a more complete 
account of these alloys. 



•*0u the Enhanced Lines in the Spectrum of the Chromo- 
sphere." By Sir Norman Lockyer, K.G.B., F.RS., and 
F. E. Baxandall, A.R.C.S. Received March 19,— Read 
March 28, 1901. 

In the recently published account* of the spectroscopic results 
obtained by members of the expedition from the Yerkes Observatory, 
during the solar eclipse of May 28th, 1900, although the record of the 
wave-lengths of the lines photographed on the different eclipse plates 
is of great value, exception must be taken to the method of assigning 
origins to the lines. This question is so important just now that it is 
desirable to deal with it without delay. The only origins which 
Professor Frost appears to accept are those given by Rowland to any 
moderately strong solar line which agrees in position, either exactly or 
very nearly, >vith an eclipse line. In discussing the eclipse lines he 
has made specific allusions to the " enhanced " lines of some of the 
metals, and to their relationship — or non-relationship — to the eclipse 
lines. 

On p. 347 he says, " These plates give no evidence of any relation- 
ship between the bright lines and the * enhanced ' lines, or lines 
distinctly more intense in the spark than in the arc spectrum, although 
Sir Norman Lockyer has attached much significance to a supposed 
connection between them. Some of the enhanced lines are present 
and some are not, or at least were not conspicuous enough for measure- 
ment." In the paragraph immediately following, he says, " In case 
of titanium, for which Lockyer gives 48 enhanced lines within 
our limits, we may summarise the comparison iis follows : 1 7 lines do 

• Frost, ' Ast-Phye. Joum.,' vol. 12, p. 307, 1900. 



(hi the Enhanced Lines in the Spectrum of the Chromosphere. 179 

not appear as bright on the eclipse phttes ; one pair is doubtful, 
the remainder occur as quite strong lines of the ordinary dark line 
spectrum, and hence would be expected to appear in the reversing 
layer, as they do." 

If a difference of 0*3 tenth metre be allowed between the wave- 
length of an eclipse line and that of the possibly corresponding metallic 
line (and in some cases Professor Frost accepts a difference of 0*35 or 
more between his adopted wavelength and Rowland's solar wave- 
length), the seventeen lines above mentioned dwindle down to ten. 
That leaves, then, thirty-eight out of forty-eight of the enhanced lines, 
or about 80 per cent., which agree in position within 0*3 tenth-metre 
with the eclipse lines. Surely this shows as close a relationship between 
the enhanced lines of titanium and the eclipse lines, as that between the 
latter and the stronger of the Fraunhofer lines, for it is stated on 
p. 345, "of 171 of Rowland's lines, 61 per cent, were measured as 
bright on the plates." 

Nowhere has it been contended that the whole set of enhanced lines 
belonging to any one metal are represented in the spectmm of any one 
celestial body ; what has been stated is that the enhanced lines of some 
of the metals are, in general, of paramount importance in the spectra 
of some stars {e.g,^ a Cygni), specially prominent in others {e.g., y Cygni, 
the spectrum of which, with the exception of the absence of helium 
lines, very closely resembles that of the chromosphere), and are a 
marked feature of the spectrum of the chromosphere itself. 

Professor Frost either has not noticed, or does not point out, that 
most of the enhanced lines of titanium, as compared with the ordinary 
lines of that element, are specially prominent, and are amongst the 
lines of greatest intensity in his list, as shown in the following table. 
The first two columns of the table contain respectively the wave- 
lengths and intensities of Rowland's solar lines (in the region covered 
by the eclipse lines), which have an intensity of 2 or more, and which 
have been ascribed to Ti only. Double assignations, of which Ti forms 
one, have been omitted, as it is difficult, if not impossible, to determine 
what propoi tion of the intensity of the solar line is due to each element. 
The third column indicates whether the titanium line at the given 
wave-length is an enhanced one or not. The fourth gives the wave- 
lengths, the fifth and sixth the intensities, and the eighth the origins 
which Professor Frost has adopted for the corresponding eclipse lines, 
and the seventh the intensities of the lines reduced from the Kensing- 
ton eclipse photographs. To make them roughly comparable with 
Professor Frost's, these intensities have been multiplied by ten through- 
out, as 1 is adopted for the weakest lines in the Kensington photo- 
graphs, whereas he adopts 10 for lines just visible. 



180 



Sir Normau Lockyer and Mr. F. K Bazandall. 







1 




1-3 


r 








5 S ■s.S 


B^ 


^1 ^ 








s § es 


*l 


^ 2 




• 


f 


•e t> »| 


i: 








1 


J3 -^ E 


T £ 


a *** 


1 

s 


PI 


1 1 lis !i 

1 1 J 11 -IJ^ 


II 
It 


T3 






H H ^ 


CM 


M 


1 
1 






It 




H.S 




&> 














•JQ 












1 




1 


J ■ 












■i 


£ H 


£ 1 I 3 IS 


1 3 


s 


a 




1 








■§ 
















g 




L 








s 


2 






M 








& 


2 




s 


i 


i- 


s (^s s a 


2 1 


?, 


3 


t^ 




;^ 


1 


o 
















^ 






K 


5 


S 










w 


■«> 


^3 










1 




1 





£ 


1 


sssas "s ? 


2 e 


s 


a 






l-H 




^ 






















•s 












« 








O IB fl 


^1 


;3 

1 






5^§ 


3553 Sf? ^ 


" 




1 




-^ 






CM 


^ C 


£OPOOOO^^S 


O Q g 


o- o g 




*-* 




^geoooscg; 


c a ji. 


o fS ^. 




f ^ 


sf- 


^«a^««a4Mt»4 M 


rt M M 


w m re 




S 


t 


2?SS2&?3S 


=sg 


SSS 


1 


ji 


1 

>-* 




ill 


III 



On the EnTuMUsed Lines in ths Spectrutn of the Ghrofnasphere. 181 



1^ 

+ 



ss 



2 . o S 






I 



.s 






I! 



^1 



*P^ OQ 









S 



BhS 



I S$ SISS 



S S ISSS 



? 33 ^ I S «« 

9 99 ^ ^9 



<&4 

I 



I 



S3S £! S SSS '°^ 



SSS 3 2 »Sig IS 



^S-^j^ O CO coqO'3 o^ 






8«§ l§8^§|.5|.§i§ 



Oil (M 04 •<« CO CO ^OlMOl 



000009 lO 09 Cd 01 01 kO to 00 CQ 09 



99999 9999 9 



8^^ SS^?i|3^^^SS 



£11999: 



182 



Sir Norman Lockyer and Mr. F. R BaxandalL 



1 



o 
o 



^ 
^ 

T3 

o 

^ 



3 

I 

o 

s 

00 



<^ 







i 

a 






1 
1 


a. 




- 


1 

m 
C 




S3 SS 




8 

1 

-3 


2 
1 

1 


1 


III ?3 


III S'-S 




32 

til sr^ 


1" 


§gsgg£ii3S=s9g 




TO^'*«fffl'S^t5^l5^m-*CO«9l 




'9" 




??SS?SSS3g323S; 



On the Enhanced Lines in the Spectrum of the Chromosphere, 18$ 

In the above list of solar-titanium lines there are thirty-three which 
are not " enhanced " in the spark spectrum. It will be seen that 
twenty-three of these — or 70 per cent. — have no corresponding line 
(within 0*3 tenth-metre) in Professor Frost's record of eclipse lines. 
Of the nine eclipse lines in the table which do agree approximately in 
position with unenhanced titanium lines, two are with certainty due to 
other metals, and in another case there is more evidence for an iron 
origin than one of titanium. These are indicated in the column for 
remarks. The remainder are nearly all lines of insignificant intensity. 

Of the twenty " enhanced " lines of titanium which occur in the list, 
nineteen have corresponding lines in Professor Frost's eclipse spectra^ 
the remaining one being also possibly represented, but it falls so near 
the strong Hy line that it might be easily masked. Not only are they 
represented in the eclipse spectra, but in nearly every case the corre- 
sponding eclipse line is a prominent one, as will be gathered at once 
from a glance at the tabular list given. 

Professor Frost summarily dismisses the significance of the enhanced 
lines of titanium in the eclipse spectra, because " most of them occur as 
quite strong lines in the ordinary dark line spectrum, and hence would 
be expected to appear in the reversing layer, as they do." But if he 
would expect one line of a certain solar intensity, he should expect all 
lines due to the same element which are of an equal solar intensity, to 
appear in the eclipse spectra. Yet another glance at the foregoing 
table will show that many of the titanium lines strongly represented 
in the eclipse spectra arc of the lowest intensity in the Fraunhofer 
spectnim, and that if lines of a certain solar intensity be considered, 
those that are enhanced lines appear in the eclipse spectra, whereas 
the unenhanced ones do not. 

In this comparison no account has been taken of the relative 
intensities of the lines in the titanium spectrum itself. Hasselberg 
has published* a lengthy list of titanium arc lines, and in the region 
covered by the eclipse spectra records about 250. To compare all 
these with the eclipse lines would take too much time and space, 
nor is it necessary. To show the difference in behaviour in the 
eclipse spectra of the enhanced and the strongest arc lines, two 
separate lists of titanium lines have been made. The first, which 
follows immediately, contains all the enhanced lines which occur 
in Hasselberg's arc list, and the intensities of Professor Frost's and 
the Kensington eclipse lines which correspond within 0*3 tenth-metre 
are also given. 



« ' Kongl. Srenska Yetenskaps Akad. Handl.,' rol. 28, No. 1, 1^95. 



184 Sir Norman Lockyer and Mr. F. K Baxandall. 







1 


+ 


1 

com- 
i-20. 
that 


i 




1 


^ i 


fsi 1 ^ 


1 




+ 


i i 
1 & 

1 1 
s. . 1 . 
1 1 •? 


|8h 1 i2 


i 
1 

.3 

1 


00 

1 


^ 1 
1 1 


CO 8*^ 9 

•az! 2 1- "^ 


J 




1 |8 


n £ -s 








fi i I"! 


.slflM s 






1 i>i 1 P 

t> fi S H (£ 


i^P i 


i 




n 


1 1 


^- <5^J 


o fl — — u! 

H &=< g HH'^ 






^ o 


P4 


PS 


Ui 


QQ 




d 










2 




1. 


8 








< 
a 




a 
1 




^s 


IS^S^ 


S S S IS:$ 


^ 




M 










Ji 




1 
















1 




»-5 








^ 


1 
1 


i 


§ 


|. 


S 1 


-">22- 


8 1 S IS^S 


"i 






.-- 


M 








-H 




-• s 


•c 


. 














a 


Pk 


1 


8S 


§ssss 


51 g S S§S 


i 


















'S 






X 








s 




II 


s« 


sssgss 


CO 5« 00 95 o> oi 
g g 2 "^ 


o 




1 ^i 




i^qi?:;: 


a 




00 








1 




s| 


01 com 


Ud 09 »0 "9 00 ( 


M 10 KD <0 lOOTf 


1 


§ 1 • 
gig 


^' 


S?$ 


2£g?§ as a 2 sss 








Q 1-4 f-^ 1— ) f-4 t 


5^' ^ 5 535 



On tlie Enhanced Lines in the Spectrum of the Chromosphere. 185 



OQ 

+ 



8 "f 



+ 
3 



i^ 



P4 



CMDH 






11' 

p 

So o 

P4 P4 









S 



Ud toiQO o^^ UdOQ 
to 9^cD t^t»t^ t^t^eo 



iweeiHOd 00 CD lo ^ ^ ih 



OQ Q Q »» I Q ^ Q 
r-l^ 09 01 I 2 04 QD 



I 



g ..g«»g g§5i g^g 



S8 


S« 


^ 


? 


00 


2S 
99 


CO 013 

59 




1 


2 

9 



9 91^11 999 999 



^00 CQ <0 00 09 09 09 91 09 



^00 lO lO 00 CO 00 O to CO lOCO^ 



rx Ol 00 m j ^ tA «0 t» 00 

9^ 99^^^? 9 9 



S? ? ?885i3Sg SSS 



illi 



i9i 



188 Spectrum of Chromosphere, 

strong as the majority of those which are the representatives of the 
enhanced lines. 

In the case of iron, all the well-enhanced lines are represented in the 
eclipse spectra, but they are not of quite the same prominence as the 
titanium enhanced lines. They are, so far as their intrinsic intensities 
in the iron arc spectrum are concerned, quite insignificant lines as 
compared with the majority of other iron lines, but their importance 
lies in the fact that they are a class of lines of special behaviour, being 
relatively stronger in the spiirk spectrum than in the arc. In the 
eclipse spectra they are undoubtedly represented by stronger lines 
than are the great tiuijority of unenhanced iron lines, however strong 
the latter may be in the iron arc spectrum itself. 

Owing to the great number of iron lines in the solar spectrum, a 
comparison similar to that given for titanium over the whole region 
covered by the eclipse lines would necessitate the compilation of a 
very lengthy list. But whatever evidence there is either one way or 
another should be revealed by a comparison over a limited region, so 
it is proposed to take that between A 4500 and \ 4600, since the 
proportion of enhanced to unenhanced iron lines is there greatest, 
and therefore a better opportunity is afforded of a fair compjirison of the 
behaviour of the two classes of lines. The table given on p. 187 is 
arranged in exactly the same way as in the case of titanium, with 
the exception that there is an additional column showing the inten- 
sities in the arc spectrum, as recorded by Kayser and Riuige. 

It will be seen that the unenhanced lines are here also unrepresented 
in the eclipse spectra, with the possible exception of three, which are 
recorded as very weak lines in one of Professor Frost's spectra, Imt are 
missing from the other. All the enhanced lines, however, although 
they have tlie weakest arc intensities, appear in each of the eclipse 
spectra, and have abnormal intensities compared with those corre- 
sponding to the unenhanced lines. It must be pointed out that only 
four of the nine enhanced iron lines in the part of the spectrum con- 
sidered appear in the above list, l)ecause they are the only ones which 
are given in Kowland's origins for solar lines. At least four out of 
the remaining five — those at AA 4515-51, 4522*69, 4556*10, 4576*51, 
probal)ly correspond to the solar lines 4515-51, 4522*69 (or possibly 
4522*80), 4556*06, and 4576*51, to which Rowland has assigned no 
origin. The outstanding line at A 4541*40 is doubtfully present 
in the solar spectrum. The first three of these five have correspond- 
ing lines in the eclipse record ; the other two have not. In the 
Kensington reductions of eclipse spectra there are, however, lines 
agreeing (within 0*3 tenth-metre) with every one of the enhanced 
lines mentioned. 



On the Arc Spectrum of Vanadmm, 189 



" On the Arc Spectrum of Vanadium." By Sir Nokmax T.ookykr, 
K.C.B., F.E.S., and F. E. Baxandall, A.R.(;.S. IN^eived 
March 19,— Read Marcli 28, 1901. 

The spectrum of vanadium is so important, especially on aecoimt of 
the prominent part which lines of that element play in the spectra 
of sun-spots, and the existing records of vanadium lines differ so 
considerably, that it has l)een thought desirable to publish a list of 
the lines reduced some time ago from the Kensington photographs of 
the arc spectrum. 

These photographs were obtiiinod by Mr. C. P. Butler with a 6-inch 
Rowland concave grating of 21^ feet focal length and 14,438 lines to 
the inch. The region of the spectnmi investigated extends from 
X 3887 to X 4932, and occupies on the plates a length of 16 J inches. 

The sources of the spectra were (1) vanadium chloride, and (2) a 
pure sample of vanmiium oxide supplied by Sir Henry Roscoe, to 
whom we wish to express our thanks. In each cjise they were 
volatilised in the arc between poles of the purest silver which could 
be obtained, and which were kindly placed at our disposal by Sir 
W. C. Roberts-Austen. These are used l)ecause the number of lines 
due to the poles themselves is so small compared with that produced 
when carbon poles are employed, that it is much easier to detect the 
lines really due to the substance imder consideration. 

Lists of lines in the arc spectrum of vanadium have l)een published 
l»y Rowland and Harrison,* and by Hasselberg.t The former 
investigators used some compound of vanadium (not stated in their 
paper) volatilised on carbon poles ; the latter employed poles made of 
the metal itself. 

The three records natuiully contain a large number of lines in 
common, but there are many differences between any two of them for 
which it is difficult to account. To show these differences it has been 
considered best to give side by side in tabular form the lines in the 
three lists, and analyse the lines special to any one list, with the 
object of cither properly establishing their claim to be accepted as 
true lines of vanadium, or possibly tracing them to their real origin. 
It may be safely assumed that lines common to any two of the lists 
really belong to vanadium. 

To eliminate lines due to inipiuities, the vanadium spectrum has been 
directly compared with the arc spectra of all the other elements avail- 
al>lc at Kensington, photographed exactly on the same scale. If the 
** strongest*' lines of an element are not represented in the vanadium 
sj)ectrum, apparent coincidences with any of the " weaker " lines are 

• * Astro.- Phys. Jour.,' vol. 7, p. 273, 1898. 

t • Svenska AVtenskaps Akad. Handl.,' vol. 32, Xo. 'i, \%\Vd. 

V 1 



190 



Sir Norman Lockyer and Mr. F. E. Baxandall. 



not accepted as furnishing any proof of the existence of that element 
as an impurity in the vanadium. This comparison shows that, in 
addition to those belonging to silver, the only lines which with any 
degree of probability can be attributed to other metals, are traces of 
the very strongest lines only of iron, manganese, chromium, cobalt, 
calcium, strontium, aluminium, and lead. Such lines (a list of which 
is given later in the paper) have been left out of the following table. 

Although Sowland gives his wave-lengths to one-thousandth of a 
tenth-metre, for convenience of comparison with the other records his 
values are quoted, throughout the present paper, to the nearest 
hundredth of a tenth-metre. A brief reference must be made to 
Rowland's scale of intensities. In his paper he states that the scale 
he has adopted is from 1 to 15. There are, however, several intensities 
given which are beyond these limits; but they are probably due to 
tjrpographical errors. Such cases are indicated in the column for 
remarks. It would seem rather difficult to reconcile his adoption of 
eruch a scale with the opinion expiessed in the introduction to his 
" Preliminary Table of Solar Spectrum Wave-lengths " to the effect that 
" the ordinary scale from 1 to 10 or from 1 to 6 is far too limited for 
the spectral lines, especially for the metallic spectra; 1 to 1000 is 
hardly great enough for the enormous difference in intensity. The 
small range, 1 to 10, ordinarily used gives an entirely wrong idea to 
the worker in this subject, and many books with spectroscopic theories 
might have been saved by using a scale from 1 to 1000." 



Vanadium Arc Lines. 
Comparison of Kensington Records with Hassclberg's and Rowland's. 



Kensington. 


llasselberg. 


Howland. 

Int. ' Remarks. 




Int. 


' 


Int. 


\, 


Max. 


\. 


Max. 


A.. Max. 






= 10. 




= 4-5. 


= 15. 




3887-69 


<1 






. 1 




88-20 


2 


3888-23 


1 






88-47 


3 


88-50 


2 






89-36 


1-2 










89-91 


<1 










90-30 


7 


90-33 


3 


3890 -30 4 




91-25 


5 


91-27 


2 






91-88 


1 










92-53 


2-3 






92 -47 4 




92 95 


6-7 


93-03 


3 






93-88 


<1 










94-16 


4-5 


94 19 • 2 






95-86 


2 3 








i*6-29 


4 


96 29 


2 


96-26 2 





On the Arc Spedncm of Vanadium, 
Fafwdium Arc Ziwe*— continued. 



191 



Kensington. 


Hasselberg. 


Rowland. 








1 






Remarks. 




. Int. 


; Int. 




Int. 






A. Max. 


A. Max. 


X. 


Max. 






-10. 


=4-6. 




«16. 






3896 -83 ; 2 












97-20 4 


3897-22 ! 2 










9817 ; 6 


98 15 ; 3 


3898*08 


1 






98-44 ; 3 


1 










99 -23 3-4 


99-30 1 1 










8900*29 4-5 


3900-33 ' 2-3 










01 -28 , 4-5 


01 -30 2-3 










01-81 2 












02-45 : 10 


02 -40 , 3-4 
02*71 ; 1 


3902 -37 


7 






03-32 3-4 


03-42 1 1-2 










03-86 1 <1 


1 










04-61 i 3-4 


04*63 1 1 










06*92 ' 4 


06*89 2 










07-33 ' 2 












08-46 • 3 












09-68 1 <1 


1 










09-96 1 9 


10 -01 3 


09-99 


5 






10-57 <1 












10*92 , 4 


10-95 ! 2 










11-90 1 


I 






• 




12-35 


5 


12-36 1 2-3 










13 04 


3 


13 03 2 










13-71 


1 












14-08 


<1 












14-49 


4 


j 


14-44 


1 






15*30 


1-2 












15-57 


2 












16*57 


3-4 


16 -55 1-2 


19*60 


1 






20-10 


1 


20-15 1 










20-67 


4 


20-65 1-2 










22 11 


4 


22 15 2 


22*02 


1 






22*57 


5 


22 -58 1 2-3 


22-55 


3 






24-85 


5 


24-84 1 2-3 


24*77 


3 






25 -36 


5 


25 -36 i 2 


25-35 


8 






26-64 


<1 








1 




26-86 


1-2 








I 




28 07 


5 












28-64 


1-2 














29-93 


1 


j 










30 19 


6 


30-19 , 2-3 










31-46 


5 


f 31 -40 : 1 
I 31 -50 i 2 


33-77 


3 


Ca(K). 




34-18 


5-6 


34 16 


3-4 










35-28 


4-5 


85-28 


2-3 










36-43 


3-4 


36-42 


2 










87-65 


3 


37-68 


2 










38-37 


3 


38-35 


2 










89*04 


1-2 














39-49 


3 


39-48 


2 








\ 



192 



Sir Noriuaii Lockyer and Mr. F. E. Baxandall. 
Vanadium Arc Lines — continued. 



Kensingtun. Hasselbcrg. 



A. 



3940 -75 
41-40 
42-18 
43-81 

45 -36 

46 04 
48-79 
50-38 
6212 

63-78 
64-64 
68-29 

72-12 
73 -53 
73-79 
75-48 
77-88 
79-31 
79-61 
80-66 
81-78 
84-51 
84-78 
88-21 
88-98 
89-95 
90-72 
91-22 
92-95 
95-08 
97-31 
98-91 
4000-24 
03-12 
03-70 
05-90 
08-33 
09-99 
11-50 
13-69 
15-26 
16-86 
19-18 
19-58 
20-73 
22-07 
23-28 
23-48 
24-63 



Int. 
Max. 
= 10. 



1 

<1 
3 
4 
5 

3 



1 
3-4 
1-2 

2 

3 

3 

3 
4-5 

3 
3-4 
<1 

4 

I 

7 

1 



34 

7 

2 

3 
2-3 
4-5 
<1 
1-2 
2 3 
<1 
1 
<1 
<1 
<1 

1 
2-3 
2-3 
3-4 
<1 



3940 -75 
41-40 
42-16 
43-77 



50 -37 

52 09 

63-77 

68-24 

72-10 
73 -49 
73 '-79 



79-30 
79-59 
80 -66 



84 -75 
88-97 
90-71 
92-95 



1 
1-2 

2 
2-3 



15-20 



97-30 


1-2 


98-87 


3 


4000 -24 


1 


03 10 


1-2 


03-70 


1-2 


05-86 


2 


09-94 


1 


11-45 


1 



3944 13 



52 07 
r;i -65 



Bowland. 



Int. I 
Max.| 
= 15. i 

I. 



Remarks. 



3 Al. 



Al. 



68-59 I 1 , Ca (H). 



79-54 



90-69 
92-92 

98-85 
4005-84 



23-50 



22-04 
23-51 



I 



On the Arc Spectrum of Vanaditim, 
Fanadinm Arc Lines — continued. 



193 



Kensington. 


Ilawell 


>erg. 


Rowland. 








Remarks. 




Int. 


Int. 


Int. 


A. 


Max. 


A. Max. 


A. 


Max.i 




= 10. 


-4-5. 




=.15. 

1 


4025 -47 


1 


4026-46 


1 




1 


30 05 


1-2 


30-04 


1-2 






81-36 


2 


31-37 


1-2 




1 


31-99 


4 


31 -98 


2 


4031-96 


1 


32-64 


1-2 


32 -62 1-2 






33-00 


1 


33-01 


1 


33 19 
34-62 


3 Mn. 
2 Mn. 


35-77 


4 


35-77 


2 






36-93 


2 


30-93 


1 




1 


39-76 


<1 








! 


40-43 


1-2 


40-46 


1 






41-66 


2-3 


41-72 


2 






42-80 


8-4 


42-78 


2 


42-76 


1 


46-99 


1 


47-05 


1 






48-77 


2-3 


48-77 


2 






51-10 


5 


51 11 


2-3 






51-52 


5 


51-48 


2-3 






52-60 


1 


52-60 


1 




. 


53 41 


2-3 










53 -81 


<1 










57-21 


6 


67-21 


3 


57-21 
57-96 


2 

1 Pb 


61-00 


1 


60-97 


1 






61-76 


1 










62-92 


1 










6411 


4-5 


64 09 


2-3 


64-06 


2 


65-54 


1-2 










67-96 


2-3 


67 O"} 


1-2 






68-16 


2-3 










70-94 


2-3 










71-67 


4-5 


71-67 


2 3 


71-66 


2 


72-28 


2-3 


72-30 


2 


77-85 


1 S:-. 


78-10 


1 










83-07 


S-~i 








1 


83-4-4 


<1 










84-92 


<1 


; 






88-00 


<1 








90 05 


1 


, 






90-74 


8 


90-70 


3 


90-70 


5 


92-08 


3 


92-09 


1-2 






92-55 


4 


92-54 


2 


92-53 


2 


92-81 


8 


92-83 3 






93-61 


3-4 


93 -65 2 






94-38 


3 


94 -42 2 






95-60 


7 


95-64 8 


95-61 


5 


97-05 


2 3 


97-09 12 






98-50 


3-t 


98-54 2 


98-51 


1 


98*99 


1 






' 


99-94 


9 


99 -93 3-4 


99-92 


' 1 


4101-99 


1-2 








1 



194 



Sir Norman Lockyer and Mr. F. E BaxandalL 
Vanadium Arc Lines — continued. 



• KensingtoD. 


HiMnelberg. 


BowUnd. ! 




Int. 




Int. 




Int. ! ^ 


A. 


Max. 


A. 


Max. 


X. 


Max. 




-10. 




=4-6. 




-15. 


4101 -66 


<1 








1 


02-25 


C-7 


4102 -32 


3 


4102-28 




03-54 


1-2 










04-62 


4 


04-55 


2 


04-52 


2 


04-93 


3-4 


04-02 


2 




' 


05-33 


7 


05-32 


3 






06-08 


1 








07-60 


3. 


07-64 


1-2 


07-60 


1 


08-32 


4 


08-36 


2 






09-20 


2 








i 


09-89 


8 


09-94 


3-4 


09-91 


7 , 


10-86 


1 








1 


11-22 


<1 








' 


12-00 


10 


11-92 


4 


11-92 


5 


12-60 


4 


12-47 


1-2 






13-62 


5 


13-65 


2-3 


13-64 


3 


14-69 


3 


14-69 


1-2 


i 


15-33 


9 


15-32 


3-4 


15 -31 1 7 


16 64 


8 


16-64 
16-85 


3 
1-2 


16-63 


9 


18-34 


4^5 


18-3* 


2-3 


18-32 


1 


18-76 


4-5 


18 -73 


2 






19-23 


1 










19-56 


4-5 


19-58 


2 


19-57 


3 


20-65 


4r^5 


20-69 


2 


20-65 


2 


21-08 


2 


21-13 


1 






21-75 


2-3 










22-45 


1 










22-94 


<1 










23-30 


3 










23-59 


7 


23-65 


3 






24 15 


3-4 


24-23 


2 


24-20 


1 


27 15 


1 










27-56 


<1 


• 








28-20 


9 


28-25 


3-4 


28-15 


« 


28-94 


4 


29-00 


2 






30-28 


<1 










30-44 


1 










31-07 


<1 










31 26 


1 


31 -32 


1 


31-30 


1 


32-08 


9 


32 13 


3-4 


32 13 


6 


32-93 


1 










33-86 


3 


33-92 


2 






34-61 


9 


34-61 


3-4 


,34-62 


7 


35-40 


1 










36-27 


3 


36-25 


2 






36-55 


2-3 


36-52 








37-06 


1 










37-36 


<1 










38-17 


2 










39-34 


3-4 


39 -30 


2 






41-50 


3 











Bomarks. 



On the Arc Spectinim of Vanadium. 
Vanadium Arc Lines — continued. 



195 



Kensington. 


Hasselberg. Bowlai 


ad. 1 

Remarkif. 








1 




Int. 




Int. i 


Int. 


\. 


Max. 


X. 


Max. ! A. 


Max. 




= 10. 




=4-6. 


= 15. 


4141 -91 


1-2 


4141 96 


1-2 




42*80 


1-2 


42-75 1-2 


1 


48*02 


1 


43*02 1 1 




43*47 


<1 


t 




45*62 


2 


i 




46 15 ! <1 






47 -90 1 2 








49 01 


2 3 


49 02 


1-2 




50*22 


<1 


1 




50*80 


2-3 


50*84 ! 2 




51 -46 i < 1 


51 -52 1 1 




62 80 1 2-3 


52*81 1 2 




53 -47 2-3 


53*49 


1-2 




64*16 <I 




' 




66 34 1 < 1 


55*39 


1 




65*95 1 1 


56*00 


1-2 




56*65 <1 








58*11 1 


58*14 


1 . 




68 *58 < 1 








59*82 1 6 


59-84 


2-3 4159*82 


2 


60*48 1 


60*57 


1 




62*48 <1 


62*51 


1 




66*86 1 1-2 








67 *i5 , 1 








69*08 ! <1 








• 69-37 i 2-3 


69*40 


1-2 




71 42 1 3-4 


71*45 


2 




74*18 1 4 


74*18 2 74 16 


1 


75 -24 I 1 


75 -30 1 1 




76*85 <1 


76*83 1 




77 -00 < 1 


77*02 1 




77 *19 3 


77-25 1 


■ 


77*67 1 






78*53 1 






! 


79 54 6 


79*53 


2-3 




80*12 1 






1 


80*95 1 


80*99 


1 


' 


82 -fit 2-3 


82 -2:^ 


1-2 


t 


82 -74 ! 5-6 


82 -74 2-3 82 *73 


1 




83-07 


4 1 


83*45 . 1 


83-43 1 


I 


83-60 2-3 


83-59 11 




84*55 <1 


1 




86-91 1 


86*96 1 


i 


87 -74 I 


87 *82 1 


j 


89 -95 5-6 


89*99 2-3 * 90*01 


2 ! 


91 -69 1 5-6 


91 *70 


2-3 ' 




94 13 


1-2 


94*17 


1 




95*73 


2-3 








97-43 


1 


97*45 


1 • 




97*74 


3 4 


97*77 


2 




98*74 


3-4 


98*78 


2 





196 Sir Norman Lockyer and Mr. i\ K Baxandall. 

Vanadium Arc Linen — continued. 



Kensiugton. 


Hasselb 


erg. 
Int. 


Rowland. 


Remarj[s. 




Int. 




Int. 


X. 


Max. 


A. 


Max. 


A. 


Max. 




= 10. 




= 4-5. 




-16. 




4199-75 ! <1 


' 










99 07 


1 












4200-30 


3 


4200-35 


2 








01 -05 1-2 












02-50 ! 2-3 


02-52 


1 


4202 -51 


2 




0#-34 ' <1 












04 -67 < 1 


04-67 


1 








06-28 


2-3 


05-23 


1 


05-20 


2 




06-73 


1 












10-00 


4-5 


09-98 


2-3 


10-00 


5 


ri'robablj masked in Ken- 






10-55 


1 


, . 


. , 


1 sington photograph by a 




11 -02 


1 


•• 


•• 


I strong broad line of Ag 
L at X 4212 -1 


16 -50 ; 1 


16-62 


1 








18-89 


3-4 


18-66 


2 








19-66 


1-2 


19-65 


1-2 








21-22 


1 


21 17 


1 








22-54 


1-2 


22-49 


1 








23 15 


1 












24-36 


3-4 


24-30 


2 








25-41 


1-2 


25-40 

26-78 


1 
2 


25-37 


1 


' Ti-obably maaked by Ca line 
' at A 4226 -91. 










• • 


• • 










26-87 


4 


Ca. 


27-92 


3-4 


27-90 


2 








29-92 


3 4 


29-87 


2 








32-68 


5-6 


32-62 


3 


32-60 


7 




33-09 


5-6 


33-09 


3 


33 11 


7 




34-18 


5-6 


34-12 


3 


3il5 


7 




34-71 


4 


34 -70 


2-3 


34-67 


7 




35-92 


4-5 


35-90 


2-3 


35-91 


4 




36-78 


<1 












39-15 


2 


39-12 


1-2 








39-80 


<1 












40-29 


2-3 


40-25 


2 








40-54 


3 


40-53 


2 








41-52 


3 


41-48 


2 








46-91 


1 












47-43 


1 


47-46 


1 








51-42 


<1 


51-45 


1 








53-00 


1-2 


53-02 


1-2 








55 -59 


<1 


65-60 


1-2 








57-50 


4 


67-53 


2 


57-52 


4 




59-47 


4 


59-46 


2 


59-45 


4 




60-00 


1 












60-28 


1 












60-46 


1 












61-32 


2-3 


61-37 


2 








62-30 


4 


62-32 


2 


62-31 


4 




65-26 


3 


65-28 


2 








66 07 


2 













Chi the Arc Specti^m of Vanadium, 
Fanadium Arc Linm — continued. 



197 



' Kensington. 


Hasselberg. 
' Int. 


BonrUnd. 






Int. 


1 


Int. 




A. 


Max 
= 10. 


^- , 


Max. 
= 4-5. 


A. 


Max. 
= 15. 




4267-48 


2 


4267 -50 


1-2 


' 






68-78 


6 


68-78 


3 


4268 -79 


0* 


• ? (10) 


69-89 


3-4 


69-92 


2 








70-51 


3-4 


70-49 


2 








71-75 


6 


71-71 


3 


71-71 


17* 


•?(7) 


72-93 


<1 










^ ' 


73-50 


<1 












76-60 


<1 












77-10 


5-6 


77-12 


3 


77 10 


7 




78-53 


<1 












79-12 


2 


79- 12 


1-2 








83-08 


3-4 


83-06 


2 








84-19 


6 


84- 19 


3 


84-21 


5 




86-57 


3-4 


86-57 


2 








87-93 


3-4 


87-97 


2 








89-00 


1 












91-45 


3 


91-46 


2 








91-96 


5-6 


91-97 


3 


91-98 


1 




96-30 


5 


96-28 


2-3 


96-27 


7 




97-29 


1 












97-85 


4-5 


97-86 


2-3 


97 -84 


7 




98-17 


4-5 


9817 


2-3 








98-79 


<1 












99-27 


1-2 






, 99-24 


1 




4302 '32 


1-2 












03-70 


2-3 


4303 -70 


2 


4303 -70 


2 




05-64 














06-40 


5 


06-35 


2-3 








06-76 


<l 












07-32 


5 


07 -33 


2-3 








08-61 


<1 






' 






09-75 


2 


09-69 


1-2 








09-95 


5 


09 -95 


3 


09-95 


7 




11-66 


1 






! 






11-83 


1 


• 










12-58 


1 


12-56 


1 


! 






14-11 


2-3 


14-06 ' 


1-2 








15-02 


2 






i 






15 -95 


<1 


16-02 


1 








18 04 


<1 






18-80 


2 


Ca. 


20-15 


<1 












20-49 


1-2 


20-46 


1 








22-53 


1-2 


22-51 


1 








29-90 


<1 












30 18 


6 


30-18 1 


3 


30 18 


0« 


• ? (10). 


31-28 


1 












32-60 


2 


32-56 


1-2 








32-96 


6 


32-98 


3 


32 -98 


10 




34-25 


3 


34-23 


1-2 








35 06 


<1 












35-69 


<1 






; 







Remarks. 



188 Sir Norman Lockyer and Mr. F. K Baxandall. 

Vanadiiim j4r& Linen — continued. 



Kensington. 



X. 



j Int. 

Max. 

Uio. 



Hasselberg. 



Rowland. 



X. 



4836*33 
89-31 
41-19 
42*39 
43 02 
45-39 
47 02 
47-64 
50-86 
50-97 
62-68 
53 02 
53-64 
55-14 
66 14 
56-98 
57-64 
57-86 
60-77 
61-24 
61-58 
63-64 
63-76 
64-40 
65-94 
66-76 
67-26 
68-23 
68-78 
69-24 
71-98 
73-40 
74 01 
74-38 
75-28 
75-51 
76-25 
77-05 
77*33 
78-18 
79-44 
80-75 
81-21 
81-43 
81-93 
83-39 
84-13 
84-42 
84-92 
85-53 
87-42 
88-32 



2-3 
<1 

7 
2-3 
8-4 
<1 
<1 

1 

1 
2-3 

2 

7 

2 
3-4 
4-5 

2 

2 

1 
2-3 
1-2 
2-3 
<1 
3-4 
3-* 
2-3 
<1 

1 

5 
3-4 

2 
<1 

4 
3-1. 
<1 
1-2 
3-4 
1-2 
<1 
<1 
2-3 

10 

4 

2 

1 

1 
<1 

1 

2 

9 

2 
2-3 

1 



4336-29 

41-15 
42-36 
43*00 



53-02 

55-09 
56 10 

57-60 
67-82 
60-75 
61 18 
61-57 
63-48 
63-69 
64-37 
65-92 

67-24 
68-25 
68-76 
69-25 

73-40 
73-99 



75-47 
76-25 



78-06 
79-38 
80-69 



Tut. 

Max. 

«4-6. 


X. 


Int. 
Max. 
-16. 




Bemarks. 

1 
1 


! 1-2 










3 

1-2 
2 

1 


4341-16 


10 






1 

1 4 


63-04 


1 

1 

18» •?(8). 




1 2 
1 2-3 


55-14 
56-10 


t 


• 


i 1-2 











1-2 

1 
1-2 

1 

2 

2 
1-2 

1 

2 

1-2 

1 

2 
2 



2 
4-5 



84-07 ; 1 

84-37 I 1 i 

84-87 1 4-5 I 

87-40 1-2 I 



63-69 
64-38 



68-76 



73-38 i 
73-98 I 



79-39 I !• •?(10). Strongest line in 
80 72 4 the whole spectrum. 

81-19 '■■ 1 



84 -87' !• • ? (10). Very strong lino. 



On tfte Arc Spectrum of Vanadiunu 
Vanadium Arc Lines — continued. 



199 



KensingtOD. 



Hasselberg. 



Int. 
Max. 
«10. 



X. 



Int. 
Max. 
»4-5 



Rowland. 




Kemarkff. 



4300 -13 
90-80 
91-88 
92*28 
93-28 

94 03 

95 05 
95-42 
95-77 
96-61 
96-93 

97-56 
9809 
99 63 
4400-74 
01*34 
01-91 
02 -79 
03-87 
05-20 
06 33 
06-80 
07-83 
08-35 
08-67 
12-33 
13-60 
13-90 
14-74 
15-25 I 
16-71 ' 
17 -83 
18-88 I 

20 14 

21 -77 

22 42 ; 
22-71 

23-40 

24-11 
24*77 

25*95 
26-22 
27*49 
28-72 
30 02 

30 71 

31 36 
31-91 
32-28 



9 

2 

2 

4 

3 

3 
2-3 

8 

1-2 
<1 
<1 

<1 
<1 

2 

8 

1 

1 

1 
3-4 
3-4 
3-4 

7 

7 

5 

6 
4-5 
<1 

2 

2 

3 

6 

<1 
<1 
4-5 

6 

2 
1-2 



4390-13 
90-79 
91-84 
92-24 
93*26 
94*01 
94*98 
95-40 



4-5 

1 
1-2 

2 

2 

2 

1-2 
4-5 



4300*14 



92-28 
93-26 
94 00 



95*38 i 10 



97-39 



I 



4400-74 4 4400-74 1 10 



03-86 
05-20 

06-80 
07-85 
08-86 
08-67 
12-30 



1-2 
2-3 

4-5 
4-5 

4 
4-5 

2 



03-88 

06-28 

06*80 

i 07-80 

i 08-37 

I 08 66 

12-30 



I 



16*63 8 



20-08 
21-73 
22-40 

23 32 
23 -41 



I 



3 


24*74 


3 


25-86 


5 


26-17 


4 




5-6 


28-68 


5 


29-95 ! 


2-3 


30-68 ; 


<1 




<1 




<1 





2-3 
8 

1-2 

1-2 
1-2 
1-2 
1-2 

2 
3 

3 
3 



24-08 
I 24 -74 
i 25 -59 



28-68 



16*68 



21 -74 10 



23*37 i 8 



Xot due to Fe. 



Ca. 



200 Sir Norman Lockyer and Mr. F. E. Baxandall 

Vanadium Arc Line^ — continued. 



Kensington. 



Int. 
Max. 

= 10. 



Hasselberg. 



Rowland. 




\. 



Int. 
Max 

=16. 



Remarks. 



4433 09 
34*80 , 
35-60 ; 
36-33 ! 

38 02 

39 -19 I 
41-90 . 
43-56 
44 39 
46-04 
49-78 
51 13 
52-19 
52-91 
53-30 
54-34 



2 

4 

1 

6 

7 

2 

7 

4 
6-7 

1 
3-4 
3-4 
•7 
2-3 
1-2 

1 



56-68 
57-67 
58 00 

58 57 

59 -96 
60-52 

61-18 
62-52 
6i-46 
6t-95 
65 69 
67-09 
67-87 
68-23 
68-95 
69-87 

71-51 
71-96 
73-45 
74-22 
74-91 



4434*80 

36-31 
38-02 

41-88 
43-52 
44-40 



2 3 



0-7 



3 4 

k\ 
2 3 
2-3 
2 3 
2-3 
<l 
4-5 
3-4 

(> 

<1 

<1 
<1 

5 

5-6 



I 



3-4 
3-4 

3-4 

2 
3-4 



4436-31 
i 38-00 

41-85 
43-51 
44-38 



I 



49-77 

51 09 ; 

52-19 I 
52-91 



2-3 49 -74 

2 61-07 

4 52 -18 
2 



56-68 
57 -65 
57-97 



59-93 
60-46 



2 
3-4 
2-3 



4 

4-5 



67 -Ol. 

68-19 
68-94 
69 -8S 



74 -21 

74-89 
76 06 



2-3 

2 
3~t 



3 
3-4 



54-94 
56 07 
56-67 
57-63 



I 



5S-91 
59-92 
60-48 
60-85 



1 

8 

10 

4 



65 67 



68-17 
6S-93 
69-87 
70-87 



74-21 
74-90 



77-48 


<1 








80-21 


4 


80-20 


2 3 


80-21 


84-24 


1 








86-39 


<1 i 


86 -4t 


1 




89-08 


7 


K9 0:> 


3-4 


89-10 


90-99 


4-5 


90-J)5 


2-3 


90-98 


91-36 


2 


!)1 -35 


12 


91 3 i 


91-65 


1 , 


91 66 


1 < 


91-65 



Ca. 
Ca. 



(>2-56 3-1 62-53 10 I 



Probably mnsked by strong 
Ag lino at X 4476 -29. 



On the Arc Specti'um of Vaymdium. 
Vanadium Arc Lines — continued. 



201 



KensingI 


ton. 


Hasselberg. 


Kowlnnd. \ 




Int. ' 




Int. 




Int. 


A. 


Mttx. 


A. 


Max. 


A. 


Max. 




= 10. 




= 4^5. 




= 15. 


4495 17 


1 


4495 -16 


1-2 




1 


96-24 


5 


96-26 


3 


4>496 -23 


5 


07-00 


4 


97-03 


2 






97-55 


3 


97-57 


2 


97-57 


5 


4501 00 


1-2 


4501-01 


2 


4501-00 


2 


01 -45 


I 






01-41 


1 


02 12 


5-6 


02-12 


3 


02 -12 


4 


06-30 


2-3 


06-30 


2 






06-40 


1 


06-41 


1-2 




1 


06-73 


1-2 


06-77 


2 


06-74 


1 1 


08 -10 


<1 


08-11 


1 






09-46 


2 3 


09 -49 


2 


09-46 


2 


11-63 


2-3 


11-64 


2 


11-60 


2 


13-83 


2-3 


13-79 


2 


13-79 


2 


14-36 


4 


14-36 


2 3 


14-36 


4 


15-73 


2 


15-74 


1-2 


15-73 


1 


17-75 


3 


17-77 


2 


17-74 


3 


20-33 


2-3 


20-31 


2 


20-33 


2 


20-71 


2 


20-67 


1-2 


20-69 


2 


24-39 


5-6 


24-38 


3 


24-38 


5 


25-33 


3 4 


25-31 


2 


25-34 


2 


28-19 


3-4 


28-16 


2-3 


28-17 


3 


28-64 


2 


28-60 


2 






29-50 


2-3 


29-47 


2 


29-48 


2 


29-78 


5 


29-76 


2-3 






30 -98 


3 


30-97 


2 


30-97 


3 


34 08 


3 






34 11 


8 


37-83 


3-4 


37-84 


2 


37-83 


4 


40-18 


3-4 


40-18 


2 


40-18 


4 


41-60 


1 


41-57 


1 


1 




45 -56 


7 


45 -57 


3 4 


' 45-57 


10 


49-79 


(; 


49-81 


3 


49-82 


8 


52-03 


3 


52-05 


2 


52-02 
•52-73 


2 1 
5 i 


53-25 


5-6 


53-25 


2-3 




! 


55-59 


<1 








1 


60-89 


7 


60-90 


3 


60-89 


7 ! 


64-79 


1 


64-76 


1 


64-76 


1 


70 -62 


3-4 


70-60 


2 






71 -97 


() 


71-96 


3 


71-96 


5 


77 -33 


S 


77-36 


4 


77 -35 


7 


78-89 


5-6 


78-92 


3 


78-91 


5 . 


79-38 


3-^1 


79-38 


2-3 


79-37 


2 1 


80-57 


8 


80-57 


4 


80-56 


8 i 


81-40 


1 






81-41 


1 : 


83-96 


3 


83-96 


2 


83-97 


2 i 


86-20 


1 


86-15 


1-2 






86-51 


9 


86-54 


4-5 


86-55 


8 ! 


88-97 


1 


88-94 


• 1 






91 -41 


5-6 


91 -39 


2-3 


91-41 


5 1 


94-27 


10 


94-27 


4-5 


94 -22 


10 


4600-41 


1 


4600 -34 


1-2 







Bemarks. 



il* ? 



? 53 -27. 



202 Sir Norman Lookyer and Mr. R £. Bazandall. 

Vanadium Arc lines — continued. 



Kensiogton. 





Int. 


A. 


Max. 




-10. 


4608*15 


1 


06-38 


5 


07-42 


1 


09-84 


2-3 


11-11 


1-2 


11-95 


2 


14-10 


<1 


16-20 


<1 


17-00 


<1 


18 00 


<1 


19 00 


1 


19-92 


7-8 


21-42 


1 


24-61 


5 


26-66 


4-5 


80-26 


<1 


35-38 


6 


86-36 


1 


40-27 


4 


40-92 


4 


44-24 


<1 


44-66 


2 


46*20 


<1 


46-52 


6 


48*08 


1 


49 07 


2 


58 13 


1 


54-80 


1 


35-60 


<1 


57-17 


1 


61 00 


<1 


62-00 


<1 


62-60 


1 


66-34 


2-3 


69*50 


<1 


70-66 


6-7 


72*48 


1 


73-83 


1 


79-68 


1 


80*03 


12 


81*12 


1-2 


82-93 


1 


81 57 


2 


87-11 


3-4 


88-24 


<1 


90-46 


1-2 



HaMelberg. 


EowUmd 




Int. 




Int. 


A. 


Mai. 


A 


Max. 




«4-6. 




= 16. 


4606-83 


2-3 


4606-82 


4 


07-40 


1-2 


07-39 


1 






08-68 


1 


09-84 


2 


09-82 


4 


11-10 


1-2 


11-10 


1 


11-92 


2 


; 








18-98 


1 


14-08 


1 


14-09 


1 


16-18 


1 


1 16-19 


11* 


17*03 


1 






18-00 


1 






ri9-85 
\ 19 -*j7 


2 
2-3 


19-90 


0» 


21-43 


1 


21-43 


1 


24*62 


2 


24 -68 


4 


26-67 


2 


26-67 


4 


30-24 


1 


30-24 


1 


35-86 


2-3 


35*35 


7 


36-34 


1-2 


36*84 


1 


40-25 


2 


40*23 


6 


40*92 


2 


40-92 


6 






44-24 


1 


44*64 


2 


44*62 


2 


46-17 


1 


46 16 


1 


46*69 


2-3 


46*57 


8 


48-08 


1 


48*05 


1 


49-08 


1-2 


49*07 


2 


53 -15 


1 


53 11 


1 


54-84 


1-2 






66-47 


1 


55 -41 


1 


57*17 


1 


57 14 


1 


61-01 


1 






62*02 


1 










62*61 


1 






63-31 


3 


66*33 


2 






69*50 


1 


69 -49 


1 


70 66 


4 


70-67 


8 


72*48 


1 






73-83 


1 


73*84 


1 


79-65 


1 






79-95 


1-2 


79*96 


1 


81*07 


1-2 


81*07 


1 


82-09 


1 






84-64 


2 


84*63 


3 


87 10 


2-3 


87-10 


5 


' 88 24 


1 






1 90-45 


1 


90*t4 


1 


1 99 52 


2 


99*50 


2 



Bemarkfl. 



»? (1). 



(10). 



On the Arc Spectrum of Vamidium. 
Vaiuvdmm Arc Lines — continued. 



203 



Kensington. 


Hasselberg. 


Rowland. 










1 


Remarks. 




Int. 


Int. 


1 Int. 




X. 


Max. 


X. 


Max. 


X. ; Max. 






= 10. 
1 




=4-5. 


1 = 15. 

1 




4702-70 




\ 


4702-69 1 1 




05-23 


2-3 


4705 -26 


2 


05-28 3 




06-38 


4 


06-34 


2-3 i 


06-36 1 5 




06-76 


5 


06 75 


2-3 


06-76 : 5 




07-64 


2-3 


07 62 


2 


07 -68 1 3 
08-40 i 1 
0913 1 




09-93 


2-3 








10-75 


5 


10-74 1 2-3 


10 -75 5 




13-65 


1 


13-61 1 1-2 


13-64 1 1 




U-29 


4-5 


14-28 2-3 






15-60 


<1 


1 


16-49 1 




15-62 


2 


15-61 1-2 


15-65 1 




16 11 


3 


16 08 1 2 


16 08 4 




16-39 


1-2 


16-86 


1-2 


16-38 


1 




17-89 


4-5 


17 86 1 2-8 


17-87 


5 




21-40 


<1 


21 -42 1 1-2 


21-44 


1 




21-71 


3-4 


21 -70 2-3 


21 -70 4 




23 06 


4 


23 -06 1 2-3 


2306 i 4 




23-65 1 <1 


23-65 : 1 


23-63 


1 




2407 <1 




24-07 


1 




28-85 <1 


28-85 ; 1 


28-84 


1 




29 -77 3-4 


29-73 ! 2 


29-72 


6 




30-58 2-3 


30 57 1 2 


30-67 


2 




31 -40 1 1 


31-42 ! 1-2 


31-44 


1 




31 -80 1 


31 -74 1-2 


31-74 


1 




32-17 1 


32-12 1-2 


32-11 


1 




37-90 


1-2 


37 -91 1 


37-92 


1 




38-60 


<1 


38-51 1-2 


38-60 


1 


• 


39-80 


1 


39 -79 1 


39-86 


1 




42-86 


3 


42-79 2 


42-82 


5 




46-87 3 


46-81 2 


46-83 


6 


1 


47-30 <1 


47 -30 i 1-2 


47-31 i 1 




48-70 1 3-4 


48-70 1 2 


48-72 


5 


j 


1 5118 i 3-4 


51-16 2 


51-21 


5 




! 51 -45 1 


51-45 1 


51-46 


1 


i 


51 -79 3 


51-75 2 


51-76 


5 




52 05 ' 1 


1 


52-04 


1 




54 13 3-^4 


5-1-13 2-3 


1 




57 -62 5-G 


r57-55 1 2 
[57-68 i 2-3 


67-69 


4 


1 


58-95 i <1 


58-92 . 1-2 


58 94 1 1 




59-20 , <1 


, 


59-21 i 1 


, 


04-22 1 


1 


64-22 1 1 




65-91 <1 


65-84 1-2 


65-86 i 1 




06 -82 5 


66-80 1 2-3 


66-84 7 
69-21 i 1 




72-76 1 


72-74 i 1 


72-78 ; 1 


^ 


73-29 ; 1 


73-25 


1-2 


73-26: 1 




1 76-63 ! 6 


i r76-54 
' 176-70 


2 
3 


76-64 5 


1 




1 i 


81-51 : 1 


, 


VOU L 


XVIII 










o 



204 Sir Nurmaii Lockyer and Mr. F. K Baxaiidall. 

Vanadium Arc Lines — continued. 



Kensington. 


Hasselberg. 


Rowland. 


■ 






— — 


■ 


Remarket. 




Int. 




Int. 


' 


Int. 


X. 


Max. 


X. 


Max. 


' A. 


Max. 




-10. 




= 4-5. 




= 15. 


4784-72 


2-3 


4784-65 


2 


47H4 -66 


5 


86-71 


5-6 


86-70 


3 


86-71 
89 10 


; ! 


93-15 


1-2 


93-10 


2 


93-13 
94-73 


? i 


95-35 


1 


95-27 


2 


95-29 


2 ; 


97-08 


6-6 


97-07 


3 


1 9712 


« ; 


98 19 


<1 


98 12 


1-2 


98 15 


1 


99-20 


1 


99-20 


1 


99-21 


1 : 


99-98 


2 3 


99-94 


2 


99-97 
4802-37 


4 ? 
1 


4803-24 


<l 






03-24 


1 


07-73 


5 6 


4807-70 


3-4 


07 -74 


10 


08-84 


1 






08-84 


1 


[ 19 -23 


1 


19-22 


1-2 


19-22 
23-03 


2 ' 
1 


27-03 


6 


27-62 


3-4 


27-64 


10 


29-00 


1 


29-00 


1-2 


29*01 
1 29-43 


1 

1 ; 


30-90 


1 


30-86 


1-2 


30-88 


1 


31 85 


6 


31-80 


3-4 


31-84 


8 


32-61 


6 


32-59 


3 


32-62 


8 


33-24 


1-2 


33-17 


2 


33-21 


3 


;u-oo 


1 






34-01 
34-26 

35 -a* 


I 
1 
1 


43-20 


<l 


4:i-16 


1-2 


43 19 


2 


46-80 


<l 






46-80 


1 


49-05 


1 • 


48-98 


1-2 


49 00 
49 26 
49-46 


1 
1 
1 


51-69 


7 


51 -65 


4 


51 -69 

52 -15 
5 4-11 
55 -55 


10 
1 
1 

1 1 


i 57-20 


<l 






57 -24 


1 


58-80 


<1 






58 HI 


•* , 


59 3S 


<l 


59 -34 


2 






62 -83 


2 


62-83 


2 


62-80 


4 


64-92 


7 


64-93 


4 


64-94 
70-33 


10 

1 


71-50 


2 


71-46 


2 


71 -45 
73-17 


3 
1 


, 75-71 


/ 


75 "66 


4 


75-67 


10 


80-82 


3 


80-77 


2-3 


80 -75 


6 


81-75 


7-8 


81 75 


4 


81 -75 


lu 


82 36 


<1 






S2 36 


2 


85-89 


1 


85-86 


2 


85-83 


2 ' 


87 03 


I 


87 02 


2 


86-99 


2 


90*30 


1-2 


90 32 


1-2 


90-26 


1 


91 40 


1 


91-43 


12 


91-41 


2 ', 


91 -74 


1 


01 -81 


2 


91 77 


3 



0)1 the Arc Specimm of Vanadium. 
Vanadium Arc Lines — continued. 



20;: 



Kensington. Hasselberg. 





Int. 




A. 


Max. 


X. 




= 10. 




4894-42 


1 


4894-43 


4900-82 


2-3 


4900 84 


04-60 


34 


01-59 


05 05 


1 


05 -lO 


00-05 


<1 


06 06 


08-90 


1 


08-92 


16-4G 


1 


16-48 


22-60 


1 


22-60 


25-87 


3-4 


25 83 


32-23 


2 


32-24 



Int.. 
Max. 
= 4-5. 



1-2 



Rowland. 




Int. 


X. 


Max. 


1 


= 16. 


4894-40 


3 


4900-82 


3 


04-57 


5 


05 05 


3 


07 05 




08-88 




13-28 




16-44 




19-17 




22 54 




25-84 




32-21 


3 



Bemark?. 



Reference to the foregoing table will show that the Kensington list 
and Hassel]>erg'8 contain many lines in common which are missing 
from Rowland's. This is probably due to the fact that the latter 
used carbon poles, which furnish so many lines themselves that it is 
extremely difficult to pick up all the lines really due to the substance 
volatilised on them. As an instance of this, in the region between 
A 4130 and A 4216, throughout which the structure lines in the carbon 
fluting which commences at the latter wave-length are most crowded, 
Rowland records only eleven lines, whereas in the corresponding 
region Hasselberg gives forty-nine, and the Kensington photograph 
shows seventy-five. 

Taking Hasselberg's list as a basis we find that the few lines given 
below occur only in his list. 



Lines given by Hasselberg only. 



Hasselberg. 



3902-71 
4116-85 

4210 -55 

4211 02 
4226 -78 
4476 06 
4682 -00 



Int. 
Max. 4-5 



1 

1-2 
I 
1 



RemarkH 



1 Probably masked in the Kensington photograph by 
J a broad line of Ag at A 4212 - 1. 
Probdblj masked by line of Ca nt X 4226 '91. 
„ Ag at A 4476 -29. 



v^"! 



206 



Sir Norman Lockyer and Mr. F. R BaxandalL 



Four of these may be present in the Kensington photograph, being 
probably hidden by lines of Ag and Ca. With re^rd to the others, 
reference to unpublished lists of lines in the arc spectra of many other 
elements suggests no origin which can be assigned to them. 

In addition to these lines, Hasselberg has appa^ntly observed as 
double the following lines recorded as single in the other two lists. 

Lines recorded as Double by HasselWg. 



Hasselberg. 


Kensington. 


Bowland. 




X. 


Int. 
Max. 
4-5 


X. 


Int. 

Max. 

10. 


X. 


Int. 

Max. 

16. 


Bemarks. 


3931-40 
3931-50 


1 1 
2/ 


3931 -46 


5 






1 


4423 32 
4423*41 


1-21 
l-2f 


4423-40 


4 


4423-37 


8 


1 


4619-85 
4619-97 


2^1 4619-92 


7-8 


4619-90 


0* 


•?(10). 


4757-55 
4757-68 


2 1 1 
2-3} 4757-62 1 5-6 


4757 69 


4 




4776-54 
4776-70 


I \\ 4776-63 


6 


4776-64 


5 






^ 


^ . _ 












In considering Rowland's list in relation to the two others, it is 
found that the following lines are recorded by him only. Some of 



Lines given by Rowland only. 



Kowland. 




Int. 


A. 


Max. 




15. 


3919 -60 


1 


3933 -77 


3 


3944-13 


3 


3961 -65 


5 


3968-59 


1 


4033 19 


3 


4034-62 


2 


4057-96 


1 


4077-85 


1 


4183 07 


4 


4226-87 


4 


4318-80 


2 


i 4397-39 


1 


4425 -59 


1 


4454-94 


1 





i Bowland. 


Bemarks. 


1 


Int. 




A. 


Max. 
15. 




4456-07 




Ca(K). 


, 4458-91 




Al. 


4460-85 


4 


Al. 


i 4470-87 




Ca(H). 


] 4552-73* 




Mn. 


' 4608-63 




Mn. 


i 4613-98 




Pb. 


! 4r,63-31 




Sr. 


: 4708-40 






' 4709 13 




Ca. 


: 4769-21 




Ca. 


4781 -51 






4789 -10 




Ca. 


4794-73 




Ca. 


! 4S02 -37 





Bowland. 



Ca. 





Int. 


X. 


Max. 






4^23-03 




4829-43 




4834-26 




4835 04 


1 


4849-26 




4«49-46 




4852 15 




485411 


1 


4855-55 




4«70-33 




4873-17 




4907 -05 




4913 -28 




4919-17 


1 



Bemarks. 



♦ Possihlj misprint for 4553 -27. If so, should not appear in this list. 



On, (lie Arc Spectncm of Vanadium. 207 

them are obviously due to other metals existing as impurities either in 
the poles or in the compound of vanadium which was used, and 
although several of these lines occiu- in the Kensington photograph, 
they have been discarded. Attempts to trace the remaining lines to 
other origins have been imsuccessful. 

With reference to the lines which are absent from Rowland's list, but 
which appear in the other two, it seems certain that many genuine and 
strong lines of vanadium have either not been identified by him, or 
have for some reason been discarded from his list. In this connection, 
it may be stated that many of the lines recorded by Eowland in his 
"Table of Solar Wave-lengths" as being due to vanadium, do not 
appear in his list of vanadium arc lines, though nearly all of them occur 
as strong lines in both Hasselberg's and the Kensingtotl records. A list 
of these is given on the next page. Those marked with a t are taken 
from a list of corrections which he has given* to his " Tables of Solar 
Wave-lengths." The remainder are taken from his original tables. 

Included in this list are seven lines possibly identical with lines in 
Rowland's arc spectrum, though the difference in his two recorded 
wave-lengths of the possibly corresponding arc and solar lines varies 
from ten to nineteen hundredths of a tenth-metre, a difference which is 
greatly in excess of what he claims to be his limiting error in the 
estimation of wave-lengths. 

In the Kensington list there are 194 lines which do not appear in 
either Hasselberg's or Rowland's. It will serve no useful purpose to 
enumerate these in a special table, as they can be easily referred to 
in the general comparison table given in an earlier part of the paper. 
An analysis of their intensities shows that seventy-seven are very weak 
lines, of intensity designated < 1, fifty-three of intensity 1, thirty-nine 
of intensity 2, twenty of intensity 3, three of intensity 4, and two of 
intensity 5, the maximum intensity adopted being 10. 

No other probable origin has been foimd for any of them, although 
the vanadium spectrum has been compared directly with the arc 
spectra of the following elements : — Ag, Au, Ba, Bi, Ca, Cd, Ce, Co, 
Cr, Cs, Cu, Di, Fe, Hg, In, Ir, K, La, Li, Mg, Mn, Mo, Na, Ni, Os, Pb, 
Pd, Kb, Kb, Ru, Sc, Sn, Sr, Ta, Te, Th, Ti, Tl, U, W, Yt, Zn, Zr. 

As these lines appear in the spectrum when either the oxide or 
chloride of vanadium is used, there seems to be no reason to doubt 
that they are really due to vanadium. 

Several of them are evidently present in Hasselberg's photograph, 
as in his comparison of certain vanadium linos with lines of equal or 
nearly equal wave-length belonging to other metals he records the 
following, but has left them out of his comprehensive list of vanadium 
lines, presumably as being due to other metals which exist as impurities 
in his vanadium. 

• ' Asf.-Phjs. Jour./ vol. 6, p. 384, Vm. 



208 



Sir Norman Lockyer and Mr. F. E, Baxandall. 



Lines previously recorded as V by Kowland in his "Table of Solar 
Wave-lengths," which are not included in his Vanadium Arc Lines. 



Solar— V lines 
(Rowland) ' 
A. 


Tanadium arc lines. 

1 






Hasselberg. j Kensington. 1 Romarks 






Int.. 1 


Int. 






A. 


Max.: A. 

4-5. j 


Max. 

10. 




3893 03 


13893-03 


3 3892 05 


6-7 




94 -IVt 


1 94 19 


2 94 16 


4-5 




3903 -401 


|3903-42 


1-2 3903-32 


3^ 




04 -Sit 


1 * 


1 






10-98 


10 -95 


2 ' 10-92 


4 




12-34 


12-36 


2-3 12-35 


5 




:34-iit 


31 16 


3-4 34 18 


5-6 




41 •32t 


41 -40 


1-2 41 -40 


3 


, 


42 let 


' 42 16 


2 42 18 


4 




43 -721 


i 43 -77 


2-3 ! 43 81 


5 




48-82t 




48-79 


3 . 




73-80f 


73-79 


2 73-79 


3-4 




76 -Slf 




75-48 


1-2 




4036 -921 


4036 -93 


I 4036 -93 


2 




51-20 


51-11 


2-3 51 10 


5 




09 -761 










72-30t 


72-30 


2 72-28 


2-3 




83 -091 




8307 


3-4 




92-82 


92-83 


3 92 -81 


8 




410t-62 


H04 -55 


2 4104 -52 


. rPossiblj Rowland's ) 
1 line at A 4104-52 


arc 


04-91 


04 -92 


2 ' 04-93 


3-4 




05-32 


05 -32 


8 05 -33 


7 • 




23-66 


23 -65 


3 ; 23 -59 


7 




28-25 


28 -25 


3-.1. 1 28-20 


9 Ditto lit A 4128 15. 




79-54 


79-53 


2-3 79-54 1 


6 




4232 -76 


4232*62 


3 4232-68 


5-6 Ditto at A 423260. 




33-09 


33-09 


3 33-09 


5-6 Ditto at A 4233 01. 




92-14 


91-97 


3 , 91-96 ' 


5 6 Ditto at A 4291-98. 




4375 -10 




; 






4420 10 


4.120 08 


2-3 '4420 14 


4-5 




29-96 


29-95 


3 ' 30 02 


5 




44-57 


4.1-40 


3-4 1 44 39 


6 7 Ditto at A 4t44-38. 




57-94 


57-97 


2-3 ' 58 00 


4 




88-93 


89 06 


3-4 1 89 08 


7 Ditto at A 418910. 





Oil llie Arc SiKctrum of Vanadium. 



200 



Has sel berg. 



Kensington. 



Int. 



3975-51 1 


I 


3975-48 


4013-67 


1 


4013-69 


4020 no 


I 


4020-73 


4123-35 


2 


4123-30 


4315-00 


1-2 


4315 02 


4618-90 


1 


4619-10 



Int. 



ITasselberg*8 

imputed 

origin. 



1-2 
<1 

1 

3 

2 

1 



Ba, Co 

Ti 

Fe 
Ti, Mn 

Ti 

Fe 



Remai'lis. 



u 



There is no eyidenco that 
the lines in the Kensing- 
ton photograph are due 
to any of these metal ;». 



The following lines occur in the photograph, but have been left out 
of the Kensington record as they are considered to be undoubtedly due 
to other metals. 



Lines of other Metals which occur in the Kensington Vanadium 

Spectrum. 



A. 


Int. in 
V. 


Origin. 


A. 


Int. in 
V. 


Origin. 


3933 -83 


5 


Ca 


4215-66 


<1 


8r 


44-16 


1-2 


Al 


26-91 


6 


Qi 


61-68 


2 


Al 


50-93 


<1 


Fe 


68-63 


5 


Ca 


54-49 


2 


Cr 


81-87 


4-5 


Ag 


74-91 


2 


^' , 


95-46 


2-3 


Co 1 


89-87 


1 


Cr ' 


4030-92 


3-4 


Mn 1 


4302-68 


<1 


Ca 


33-22 


3 


Mn 


07-96 


1 


Fe ! 


34-64 


2-3 


Mn 1 


11-21 


1-2 


Ag 1 


45-90 


2 


Fe j 


25-92 


1-2 


Fe 


55-44 


10 


Ak 


83-70 


2 


Fe 


57 -97 


3 


Pb 


4404-70 


<I 


Fe 


63*63 


1-2 


Fe 


76-29 


6 


Ag 


4121 -48 


2-3 


Co 


4668-70 


7 


Ag 


4212-10 


10 


Ag i 









All these lines are the very strongest in the spectra to which they 
respectively belong, and although in the vaiijulium spectrum there are 
other lines apparently identical in position with some of the weaker 
lines of Fe, Mn, Co, and Cr, a comparison of their relative intensities 
in the two spectra shows that they cannot reasonably be ascribed to the 
presence of such metals as impurities in the vanadium, but must l)e 
accepted as genuine lines of both metals, so far as the dispersion 
employed enables us to form an opinion. These are given in order of 
wave-length in the following table : — 



210 Prof. R Warren. Chi the Development of the 

Coincidences of Vanadium Lines with Lines of other Metals. 



A 
(Kensing- 
ton). 



3884*16 

8913-71 
77-88 

4052-60 
68 16 
70-94 
83-07 
90-06 
90-74 

4224*36 
34*18 

4408*35 
16-26 



Origin 

of 

coincident 

line. 



Cr 
Fe 
Fe 
Mn 
Fe |Mn 
Fe 
Mn 
lin 
Mn 
Fe 
Co 
Mn 
Fe 



Int. 


Int. of 


in 


coincident , 


Y. 


line. 1 


4-5 


4 


1 


2-3 


2 


4-5 


1 


4 


2-3 


3|6 


2-3 


2-3 


3-4 


7 


1 


4 


8 


1-2 


3-4 


3 


5-6 


1-2 


6 


4 


3 


10 



A 
(Kensing- 
ton). 



4427*49 
67*09 
07*00 

4514*36 
17 75 
25*33 
34*08 
49*79 

4603*15 
26-66 
54-80 

4709*93 

4871*50 



Origin 

of 

coincident 

line. 



Fe 

Co 

Cr 

Fe 

Fe 

Fe 

Co 

Co 

Fe 

Mn 

Fe 

Mn 

Fe 



Int.\! 


Int. of 


in ' 


coincident 


V. 

1 


line. 


4 


7 


2-3 


4 


4 


5-6 


4 


<l 


3 


1 


3^ 


4 


3 


4 


6 


5 


1 


5 


4^ ; 


5 


1 ' 


4 


2-3 


7 


2 


6 



"A Preliminary Account of the Development of the Free- 
swimming Nauplius of Leptodora hyalina (Lillj.)." By 
Ernest Warren, D.Sc, Assistant Professor of Zoology, 
University College, London. Communicated by l^rofessor 
Weldon, F.E.S. Eeceived February 4, — Eead February 28, 
1901. 

Leptodora appears to be a primitive daphiiid in retaining a long, 
markedly segmented alxiomen, and for this reason it seemed likely that 
an investigation on the development of the winter-generation might 
throw some light on the vexed questions in Cnistacean development. It 
was more particularly desired to ascertain whether any vestige of a 
coelom occurred, and that if so, whether any remnant of it persists in 
the adult. With this object in view, it was necessary to inquire into the 
origin of the genital cells and of the antennary and maxillary glands. 

In April, 1898, Professor Hickson obtained a few nauplii from Lake 
Bassenthwaite, Cuml)erland, and later in the year a large numl)er of 
adults. This material was most generously placed at my disposal by 
Professor Weldon, and I wish to express to him ray sincere thanks. 

The material was insufficient for my purpose ; and in the following 
spring I visited Lake Biissenthwaite to try to obtain fresh material, 
but I met with very little success. Last spring, however, sufficient 
material was obtained to continue the investigation.* The preserWng 
reagent employed was Flemming^s solution (strong formula). 

• I am indebted to the Royal Society for a Gorernment Grant in connection 
m'th obtaining this material. 



Free^mmming Nmiplhts of Leptodora hyalina (ZUlj.). 211 

Fig. 1 represents the youngest nauplius tow-netted. It should be 
noticed that Ant. 1 is not a swimming appendage. The posterior end 
of the body is rounded, as the characteristic caudal forks are not yet 
developed. The mandible already possesses the rudiment of a biting 
blade. The first and second maxillae are represented by the merest 
rudiments. Thoracic legs 1-6 are present as conspicuous buds. The 
lower lip is not yet developed. 



AftLL 



nd 




Fig. 1. — Ventral view of the youngest nauplius. Ant. 2 i» relatively much longer 
than at any other period of life, x 110 diameters. 



On each side of the proctodaeiun there is a little ectodermal pit 
secreting a cuticular (?) substance. In an older nauplius, a prominent 
spine projects out of these sacs, which are then situated at the ends 
of the caudal forks (fig. 2). These ectodermal pits bear a strong 
resemblance to the setal sacs of a Chaetopod. 

At this time the mesenteron has an incomplete lumen, but both the 
stomodseum and proctodseum have reached it. 

Above the gut there is a large collection of yolk-masses surrounded 
by a membrane of flattened yolk-digesting cells which send processes 
inwards between the yolk-masses. There is no yolk-sac duct. 

In an older nauplius the biting blades of the mandiblea »x^ \ol^x^ 



212 



Prof. E. Warren. On the DevdopfiuiU of tlie 



developed, and at every future moult the swimming ramus gi-aduall y 
becomes shorter. Relatively the mandibles travel somewhat forwards, 
so as to be situated nearer to the mouth. The rudiment of the second 
maxilla is just visible, that of the first maxilla is only seen in a 
horizontal section of the embryo. 



, Hea,dShMd 



Ectod&w -^ 



End-s^Q. 




- AnC^GCAnd 



' MdLX^GUuid 



Fio. 2. — Dorsal view of metaiiauplius. The eiiil)ryoiiic caraiMCi*, foruu'd 1m \]w 
fusion of the two dorso-lateral swellings, is gradually extending baclv\vanl< 
over the thorax, x 110 diameters. 



In these nauplii, I met with a remarkable instance of unequal 
development in the different organs. Several nauplii which were 
presumably older than those ydih a roimded posterior end (since they 
were somewhat larger and possessed caudal forks) were, nevertheless, 



Fro -swimming Naii^pliits of Leptodora hyalina (Liflj.). 21v> 



much less advanced in the development of the internal organs. The 
subject of variation in time, and the pirtial independence of the 
different organs in development, would seem to be well worthy of 
more attention than has l>eeh paid to it. 

The lower lip appears late ; it seems to originate from paired rudi- 
ments ; l)ut the slight papillae representing the maxillae do not enter 
into its formation, for they flatten out and disappear. 

The characteristic shape of the adult thorax, whereby the ventral 
snuiace Ijearing the legs comes to be situated nearly at a right angle to 
the head, is not assiuned, as we might have expected, until the adult 
structure is attained. 

Even in the quite young nauplius the ectoderm over the head is 
cuiiously modified; the cells are large and possibly glandular or 
excretory in nature. They possess large nuclei towards their l)ase.s 
and are much taller than the ordinary ectoderm cells. In the adult 
animal, these cells f onn a large patch over the head, the " Kopfschild " of 
Weismann (fig. 2). I have not detected anything else of the nature 
of a " dorsal organ," and I suggest that the above-described structure 
represents it. 

As the youngest nauplius captured was a free-swimming creature 
with miuiy muscles, it might have been anticipated that anything of 
the nature of segmental coclom pouches, if present, would be much 
obliterated. Most of the mesoderm consists of a fairly uniform sheet 
of cells lying on each side of the gut. Posteriorly the mesoderm is 
more abundant and compact. The muscles of the thoracic legs are 
formed from the Iwise of the mesoderm l)and8 (fig. 3, B). The cells 



£ndSAC. 



Thi 







.t 

MascLe. 



Muscle 

B. A. 

IFiG. 3. — A. Cix)S8-scctiou of a young nauplius just behind the rudiment of 2nd 
maxilla. The exit-duct of the maxillary gland can be seen passing up into 
the dorso-lateral swelling. 

B. Cross-section of a slightly older nauplius ; it is a little post<»rior to A. 
Differentiation of end-sac and part of glandular tube can be seen in the dorso- 
lateral swelling. 



214 



Prof. E. Warren. On the Devdopmewt of tlu 



which will form muscle, are considerably larger than the rest of the 
mesoderm cells and stain more deeply; they become arranged in 
parallel cords. By the arrangement of the primitive muscle, the 
segmentation of the abdomen is marked out quite early in the life of 
the nauplius. 

The cells which will form the heart, can be distinguished at an 
early period. In the thoracic region, the dorsal portion of the mesoderm 
bands consists of two closely applied layers of flattened cells (fig. 3). 
These layers gradually grow up over the yolk-sac, and those of one side 
meet their fellows of the other side in the mid-dorsal line. Separation 
of the two layers now occurs, and the sac thus formed is the heart 
(figs. 4 and 6). The pericardial space originates by two processes — 



H&art 



End S^c. 



f%30dirfrt*4} 
Band, 




Fig. 4. — A. Longitudinal vertical section tlirougli the dorso-latcral swelling ; it is 
taken at some distance from the mid-dorsal line (see fig. 2). 
U. Similnr section taken close to the mid-dorsal line. 

(1) the gradual separation of the ectoderm from the heart-sac, and (2) the 
disintegration of the deeper layers of this thick ectoderm (figs. 2, 4, 5, *). 
There appears to be a definite floor to the pericardial space, consisting 
of flattened cells conunuous Anth those of the heart (fig. 5, B), but 
the roof would seem to Im) simply the general dorsal ectoderm of the 
thorax. 



Free-swimming Naupliics of Leptodora hyalina {LUlj.). 215 

The blood-corpusdes are large and frequently spherical. I think it 
is probable that they are budded oft* from the compact mesoderm at 
the posterior end of the body, but it is very difficult to be certain 
about their origin. 



fAxrcuof^. 




Fia. 5. — A. Obliquely transvorBO tcction through the dorso-Iateral swelling of a 
metouauplius. The maxillary gland has become sharply differentiated from 
the imbedding ectoderm. 

B. Similar section through an older raetanauplius ; the space marked f has 
developed. The space * will soon become continuous with the space around 
the heart. 



In the e^irliest naiiplius obtained the gonad is quite definitely 
formed. Without doubt the generative cells originate exceedingly 
early, probably they coiUd have been distinguished in the blastosphere 
stage as Grobben has described in the case of Moina. The ovary 
becomes surrounded by a layer of mesoderm, and the generative duct 
seems to be solely mesodermal. The main mass of the mesodermal 
bands }>ecomes converted into the characteristic double-layered fat- 
body lying on each side of the gut. 

The origin of the antennary and maxillary glands has very con- 
siderable morphological interest, and I have devoted much care in 
endeavouring to elucidate it. The development of the maxillary gland 
will be described first. 

On the lateral sides of the body of my youngest nauplius, just posterior 
to the vortical plane passing through the second maxilla, the ectoderm 
is several layers thick. This thickening is more pronounced dorsally, 
and on surface view of the nauplius we can see a distinct doT^^\aX«wiL 



216 Prof. K Warren. On the DevdopnieiU ofUie 

swelling on each side. In the lateral thickening of ectoderm, a band 
of colls passes nearly vertically downwards to the papilla representing 
the second maxilla. The band will become the exit-duct of the future 
gland; the band extends upwards into the dorso-lateral swellings 
mentioned above (fig. 3, A). It is out of these swellings that the rest 
of the gland becomes differentiated. 

Fig. 3. B is a cross-section a little posterior to A, and is taken 
from a nauplius very slightly older. Hero the end-sac can be seen 
vaguely marked out from the surrovuiding ectoderm. 

The lateral swellings containing the developing glands gradually 
extend upwards, and after a time they meet together in the mid-dorsal 
line (fig. 2). • 

There is formed simultaneously a deep transverse groove in front of 
the upgrowing swellings, and a less conspicuous groove occurs behind 
(fig. 4, A and B). 

The overhanging portion of the embyonic carapace (fig. 4, B) will 
l»e carried backwards as the animal develops, and will, in the female, 
expand into the free portion of the carapace overhanging the first two 
a])dominal segments. 

As the fused swellings (the emluyonic ciirajiace) graduiilly extend 
j Iwickwards over the dorsal surface of the thorax, the maxillary gland 

is drawn out with them into the position and shape seen in the adult, 
i At the same time there is a general expansion of the parts ; the 

\ maxillary gland l)cgins to separate itself from the surrounding ectoderm 

; (figs. 2, 3, 4, and 5, t), and the space around the heart gradually 

\ increases. There is also a cerUiin amount of disintegration of the 

I ectoderm where the dorso-lateral swellings met in the middle-line. 

I The spices marked * in figs. 2, 4 and 5 are thus formed, and ultimately 

' they become continuous with the space around the heart. 

i We have already seen that this pericardial space has a definite floor 

i of flat mesoderm cells, but the roof would seem to be simply the 

ectoderm of the b(xly-wall. The exit-duct with the external opening 
travels upwards into a dorso-lateral position, so that in the adult it is 
: nearly horizontal. 

I In the material at my disposal it is not possible to decide for certain 

! whether the antennary gland also arisas from the ectoderm, but it is 

i highly probable that it does so. 

i Fig. 6. A, B, G represent three stages in the growth of this struc- 

tiu*e. The nuclei in the intracellular duct, and connected ectoderm 

have been carefully put in the diagrams from actual sections, and their 

' arrangement cert^iinly gives the impression that the duct should be 

regarded as an ingrowth of ectoderm. 
1 Fig. A represents the condition observed in the youngest nauplius. 

^ The end-sac consists of fairly large cells which are not very dift'erent in 

■ charncicT from the cells forming the intracellular duct. At a slightly 



FreC'Sicimmiiiff Jiaujjlivs of Leptodora hyalina (LillJ.). 217 

later date (fig. B), the cells of the end-sac have become smaller, and 
there is a more distinct basement membrane; they greatly resemble 
the cells of the end-sac of the maxillary gland. In an older naupliiis 
(fig. C) the intracellular duct begins to disintegrate, but the end-sac 
remains adhering to the dorsal ectoderm for a very considerable time ; 
ultimately, however, it disappears. 



DorsAl. 




Fio. 6. — A. The antennary gland seen in transversie section througli the Youngest 
nauplius at the level of the 2nd antenna. 

13. The same gland seen in a slightly older nauplius. The eelU of the 
eud-sac are smaller, and there is a more definite basement membrane. 

C. The same in an advanced metanauplius. Tlie intracellular duct no 
longer coniniuntcates with the end-sac. 

According to these observations, the maxillary and possibly the 
antennary glands are purely ectodermal in origin, and the end-sac is 
to be looked upon as merely a terminal thin- walled dilatation of the 
glandular tube. At one time I believed that mesoderm crept up 
behind the maxillary gland (see fig. 4, A), and formed the end-sac, but 
renewed ol>8ervation convinced me that it is formed out of the ecto- 
dei HI in ilivvd cjoniimiitij with the glandular tube (see fig. 3, B). 

Tt appears from recent observations that the nephridia of Ch«to- 
pods should be regarded as ectodermal tubes which generally open 
into a coeloni, and sometimes may come into comiection with a 
generative fuiniel. In a trochosphere (^.^r., in that of Polygordius), 
the '-head-kidney" is probably budded off from the ectoderm, and 
since there is no coelom into which it can open, the tube terminates in 
a slightly dilated " flame-cell." 

Although coelora sacs are doubtless formed in the development of 
some cnistacea, yet I altogether failed to discover any traces of them 
in tlie youngest nauplius of Leptodora that I have examined; and 
even in those cases where they have been described, it does not follow 
that the antennary and maxillary glands enter into relationship Avith 
these transitory ccelom spaces. 



218 Mr. E. Wilson. The Chroxoth of Moffnctism in 

If an ectodermal origin of the antennary and maxillary glands be 
confirmed in cnistacea generally, then we should be led to regard these 
structures as nephridia, which have lost their primitive connection with 
a ccelom, and the endnaac would be looked upon as equivalent to the 
"flame-cell" of a typical intracellular nephridium. 

The above preliminary account, which has omitted all reference to 
the nervous system and sense-organs, is merely a summary of the 
results already obtained. I hope in a future publication to give a full 
account, containing careful drawings with the camera lucida. 



** The Growth of Magnetism in Iron under Alternating Magnetic 
Foi-ce.*' By Ernest Wilson. Communicated by Professor 
J. M. Thomson, F.RS. Received February 25, — Eead March 
28, 1901. 

The object of this paper is to investigate the growth of magnetism 
in an iron cylinder when the magnetising force is alternating. The 
shielding effect of induced currents in plates of iron has been dealt 
with theoretically by Professor J. J. Thomson,* and Professor J. A. 
Ewing.t The subject has also been dealt with experimentally in the 
case of an iron cylinder, 4 inches diameter, J with alternating mag- 
netising force and with simple reversal of the magnetising force. A 
cylinder, 12 inches diameter, has been experimented upon with simple 
reversal of magnetising force,§ and the shielding effect of induced 
currents studied. As the exploring coils enclosing elements of the 
cross-section of this 12-inch magnet are well suited to give the average 
induction density at four mean radii, the author thought the subject 
worth further investigation with regard to alternate currents. The 
magnet is of cast steel, and is shown in sectional elevation in fig. 1. A 
section of the 12-inch core on the line A A is given in fig. 2. Wires 
have been threaded through the holes drilled in the plane A A, 
enclosing the areas numWed 1, 2, 3, 4 (fig. 2), and another coil 
{No. 5) surrounds the core. A DArsonval galvanometer was placed 
in each of these five circuits with an adjustable resistance to control 
the maximum deflection. The deflections of the needles of the five 
galvanometers were noted simultaneously CA^ry four seconds, and 
were ultimately plotted in terms of time. The magnetising current 
in the copper coil of the magnet was observed simultaneously with the 
above <m a Weston ampere meter. The current wiis made to alternate 

• ' The Electrician/ toI. 28, p. 599. 

t 'The Electrician, toI. 28 p. 631. 

X llopkinson and Wilson^ * Phil. Trans.* A, vol. 186 (1895), pp. 93-121. 

§ HopkiiMon aud Wilson, * Journal of the Inst. Elec. Eng.,* vol. 24, p. 195. 



Iron under AUemating Magnetic Force, 



219 



by means of a liquid (CUSO4 dil.) reverser consisting of two oppositely 
fixed copper plates, each embracing a quadrant of a circle, and two 
similarly shaped copper plates fixed to a vertical spindle and capable 



Fia. 1. 




^^'hoisa 



of rotating concentrically within the fixe<l plates. The operator at 
this liquid reverser counted seconds aloud whilst listening to the ticks 
of a seconds pendulum. In this way the epoch for all the oWsri^ 
VOL. LXVIII. ^ 



220 



Mr. K Wilson. The Oratrth of Magnetism in 



tions could be noted. The speed of rotation was varied, from one 
revolution in ten to one revolution in two and a half minutes. 

The. electromotive force curves have been integrated, and therefrom 
the maximum average induction per sq. cm. of the area considered has 
been obtained. The data are set forth in the appended table. Since 
similar magnetic and electric events will happen in different sized 
cylinders at times varying inversely as the square of their linear 
dimensions, it is easy to infer what will happen in a cylinder 1 mm. 



FiG.a. 




s^oo x^ood f^tpoo 



£^OQO 



PlO. 4. 




^poo mfloo /^ooo 



£apoo 



diameter. Similar events will happen in this wire at 150 periods per 
second, as have been observed in the 12-inch core with a periodic 
time of ten minutes. A useful way of illustrating the results obtained 
is to express in the form of curves the relation between the maxi- 
mum average B over Area No. 4, that is, near the surface of the core, 
and the percentage amoimts by which this maximum hjvs to be reduce< I 
to give (1) the maximum average over Area No. 1, and (2) the maxi- 
mum average over the whole core as given by coil No. 5. This is 
done in figs. 3 and 4, in which the numljer on each curve refers to the 



Iron "imder AUti^ncUing Magnetic Farce. 



221 



frequency with a 1 mm. wire. Figs. 5 and 6 show the relation between 
the frequency in complete periods per second for a 1 mm. wire and the 
same two quantities respectively. Since a plate, with regard to 



Fio. 6. 



ioo 



I: 

























_] 


67^ 























^ 




^i 


7- 


9£&: 
















[^ 


-^ 






I 


U y^' 


CO 












^ 


^ 


^ 


- 


^ 


^ 


r^ 










Mi 


(1 ./ 


y 


y 


^ 


^^ 


^ 




/ 












J 


/ 


y 


^ 
^ 


y 






> 
J 


/ 












/, 


/ 


A 


^ 








/ 












/ 


/, 


K 


so 






^ 


/ 












/ 


^ 


/ \ 




o 
7rt/rj 


^^ 


<; 
















/ 


r 


=:i! 
rt 


L^ 




^-^ 














tea. 


w 


ih- — 1 


R-^ 


3C 


6 


4C 





j% 


a 


6l 


6 



Fretfuency 



t SO 



Fio. 6. 



5^ 



8^ 
» 



^ 







69tC 




^ — 










1 4 








— U4 






y^^C 




^^ 






- 






— ^ 




/ 


y^f^OSO 




^ 


/p9C 


2- — 








/ 


K 


^<^- 


















~ 












' 


^ 


>>- 


'^'"^ ^£0i 


ifC 

















/MO 

J6££0 



/SS30 



n 



too £00 300 -«W ^00 

rraqaency for <a Cy Under * mm. cfiaC, 



600 



induced currents in its substance, is comparable to a wire, the thick- 
ness of the plate being half the diameter of the wire, the above curves 
may be taken to apply also to a ^ mm. plate. In figs. 3, 4, 5, 6 the 
points indicated by x are the result of experiment when the magnet 
had a temperature of about 15° C. 



222 Mr, R Wilson. The Orowth of Magnetism in 

Suppose a transformer core to l)e built up of 1 mm. wires, or ^ mm. 
plates, insulated from one another, the transformer being in action 
with no currents in its secondary circuit. The reaction of the core 
upon the primary or magnetising coil will be the rate of change of the 
average induction over the whole core. The average induction per 
sq. cm. of a particular wire or plate will differ from the induction per 
sq. cm. at the surface of such wire or plate by an amount varying with 
the frequency and with the value of B at the surface. For high and 
low values of the surface B and a given frequency the average over the 
whole wire or plate differs less from the maximum at the surface than for 
intermediate values of the surface B. The relation between the perme- 
ability of the iron and the rate of propagation of magnetism in the iron 
has been explained in the case of simple reversals,* and agrees with 
what we have just observed. When the limits of B are small, that is, 
the permeability is small, the magnetism is propagated rapidly. For 
intermediate values of the limits of B, that is, when the average 
permeability is large, the rate of propagation is small. With the high 
limits of B the average permeability is small and the magnetism is 
propagated more rapidly. Setting aside the subject of magnetic 
viscosity, we should expect the average B over the whole wire or plate 
to be equal to the surface B if these induced currents did not exist. 
The curves show that for a given frequency there is an effect which 
increases the extent to which equalisation of the induction density over 
the core may be carried according as the maximum limits of B at the 
surface are on the lower or higher part of the curve of induction of the 
material. The dissipation of energy, due to magnetic hysteresis and 
induced currents, will likewise be affected since uniform distribution 
gives minimum dissipation for the same maximum average induction 
over the whole core. 

Not only have we to consider the maximum value of the induction 
density at different parts of the core, but the phase of such induction 
density. It is not necessary to publish all the curves obtained, but as 
an example one might contrast in figs. 7 and 8 the curves of E.M.F. 
obtained with periodic times of 10*3 and 2*6 minutes for about the 
same maximum magnetising force, namely, 9*6 and 9*5. In figs. 7 and 
8 the E.M.F. curves are plotted to a scale giving C.G.S. units per 
sq. cm. of the area embraced l)y the respective coils, the curve nuniher 
corresponding with the coil number in fig. 2. With 10 minutes* 
periodic time the induction is practically reversed over the whole core 
by the time the current has attained its maximimi value ; whereas 
with 2*6 minutes* periodic time the ciu-rent is again zero when the 
innermost coil (No. 1) is experiencing its maximum E.M.F. In the 
first case nearly the whole of the change for each coil aids the average 

• HopkinEon and Wilson, * Joiimal of the Inst. Elec. Eng./ toI. 24, p. 195. 



Iron under Alternating Magnetic Force. 



223 



tt 

& 









y 








1 












































' 


























/ 


























/ 














































































, 


























































J 


























j 






















h 





'^1 


L 














^ 










/ 1 
















K 




, 


^ 


y 


1 




















-u= 


-~^ 




1 
















( 


^ 


\ 






^ 




















H- 


~-~.y^ 


^ 


^ 1 


/% 


















\ 


7^ 

/ 


"^ 


sj 


' 


















\ 


r 




A i 


i 


















1 


V 




/ \ 


^ 
























/ I 


c 




















V\ 


J 


^ 


(1 




















> 


c( 






















^ 


r 


r 


\ 




















■■ / 


% 


J 


\ 




















s 


V 


I 


\\ 


V 




















\ 


s 


\\ 


i N 


\ 




















\ 


\\ 




N 






















N^ 


























V 


























1 










; 


















1 








\ 


















1 








\ 


















L 








1 


\ ' 



■^iuf} wo ^f '^^ *^ ^^ Jki3 ^ 



«a -^ 



*99J9duiY 



224 



Mr. E. WilBon. l%e Orawih 0/ Magneium in 



(No. 5) E.M.F, In the second caae the areas inclosed by Nos. 1 and 
2 coils o|ypose, and the average suffers accordingly. 
It is of interest to see what effect raising the temperature of the 



Fie. 8. 









ry 




















je l/VtA 






/ 


\ 


















ipoo 








\ 


\ 
















^ 






' 


1 \ 


















^ 










\/ 


-^ 














Z^ 










V. 




\ 




^^ 


f 












/- 


N. ,1 


\ 




\ 


,^ 

















\ 


;< 


A 






V 


\ 


\ 










1 




h 


H 


s 




1 




\\ 












k 


1 




v^ 


s 


A 




\ 






/ 


\ 




/ 




\ 








\ 


,X 




5 « 


/ 


n 


K 






-.--'^ 


< . 


\j 


K 


\ 


N 


\, 




X, 




^// 


J 


/j 


/ 


me 


in 


w//?. 


j^ 


k^ 


Ns, 


\ 








ii 


U 












\ 




V 


S, 


'3 


n 


\i^- 












1 




\ 


\ 




/ 


L 




















\ 


2 


/ 






















\ 


ff 




1 


















\y 







J 



















































magnet would have upon these induced currents. The magnet was 
heated by placing Fletcher gas furnaces around it. The heat was 
applied for about 1^ hours, and the magnet allowed to cool. The 
electrical resistance of the No. 1 coil was measured, and when it 



Iron under AUer)UUinff Magnetic Force. 



225 



became steady, indicating a temperature of about 53*" C, two sets of 
curves were taken. The points obtained with the heated magnet are 
indicated by O in figs. 3, 4, 5, 6. In fig. 9 the ciurves obtained at 



Fio. 9. 



A mo 



X 

-5 



&Q0 













f 


\ 






























\ 


\ 






























\ 


\ 


14 
































\ 


























1 


f^ 




\ 


























/ 


^ \ 


\ 


L- 




^ 


\ 




















/ 




\ 


\ 






1 


\. 


















/i 




f 


X 








\ 


















// 


L 


(* 




N 






> 


/, 


\ 












J 


/ 


r 






\ 


\ 




y 


\ 


\ 


K 








^ 


y 




1 




,^ 


\ 


^ 


\ 


i, i 


\ 




\ 






^ 


^ 




/ 




7 


rt^ 


>T / 


■tint 


^ 


\ 


\ 














\ 


^y 




1 










^ 




\ 














K 


J 














\ 


\ 












J 


















\ 


\ 


\ 








/ 


/ 


















\ 




\ 






^ 


/ 





























53° C. with a maximum magnetising force H of 8*85, and periodic time 
2*6 minutes, are given in order to enable a comparison to be made 
with fig. 8. It will be seen that coil No. 1 has an E.M.F. somewhat 
retarded at the higher temperatiure. The E.M.F. of this coil also 
suffers retardation of phase in the experiment with the lower force 
2*85, when the magnet is at the higher temperatiu'e. 

Heating the magnet has had the effect of increasing the maximum 
average value of B at the centre for the same frequency and slightly 
smaller magnetising force of the same wave-form. The relation 
between the surface density (No. 4 coil) and the average obtained from 
<K)il No. 5 remains practically the same. In this connection it should 
l)e remembered that for the same average over the whole core, a con- 
fiiderable increase in the induction density at the centre is com- 
pensated by a small decrease at the surface. It appears, then, that 
raising the temperature of the magnet tends to equalise the \\v«.y\\!Knxsdl 



226 



Mr. E. Wilson. The Cfrowtk itf Magnetum in 



go 

u 



S 

•a 

m 

O 



S 






I 



I 

E 



2-E 



I 



III 



S|9 



il I I i^i 



Kl) as 



55 O .-1 « -M O 05 i 






^ S o c 









O « M ^ -* 



sssssssss 



^ *^« « rt T^ O 3* ^ 

P4 ^ ^ p^ >. ^ 1»^ ^ 



ip^ ff» ^ » *r; « 



1^ O IS Q O O O O lO 
^ r^ lb ^rM "e ^ ^ qp 
oc_ «;^ *^^^ »i ^^ ^^ ^ o^ 



^1 1 I l^^i 



ill I ill 



IS I 






to 






iS 



§ 



s ? 



s 



I 



« 
^ 



s 



s 





















"5 






^ 



^^ 



i 



s 



§ 



s 



*9 \^ 






S Vi 



$ 



m « <- 



.,1 

'.a 



iH M OC ^ IS 



'I 



M . 


J - 


J ^ 


^ : 


r* 


r-* ■ 


6g 


e : 


^a 


S : 


&* 


d ' 


o o 


hi * 


St » 


*s ■ 


T3 fl 


*IH , 




n 


a ' 


& 



■2'ai 

1 = 4! 



S Q^ 



^^ 



°k 



'^ 






m m 

•si's 
'<3| 



lT(m under Alternating Magnetie Foixe, 227 

induction density over its section. On account of the increased lag of 
phase of induction as the centre is approached, the maximum average 
over the whole core is not materially alterecl for the same surface 
density. The force due to the current in the magnetising coils is 
smaller at b^" C. for the same maximum, average induction density 
over the whole core. For a given permeability and hysteresis loss the 
higher the specific resistance and temperature coefficient the better. 

It should be mentioned that the potential difference employed in 
these experiments was 200 volts, the excess over the magnet and 
liquid reverser being taken up by non-inductive resistance. The area 
taken for each coil is the actual area of iron in the plane of section, 
fig. 2. The areas taken for coils 1, 2, 3, and 4 are 19-8, 8-465, 19-8, 
and 2116 sq. cm. respectively. If, instead of these, we take the areas 
bounded by the centre lines of the :J-inch holes, the diminution of 
induction density would l^e 30*6, 52*4, 306, and 22 per cent, respec- 
tively. The true correction will not alter the general conclusions 
arrived at in the paper, and is a function of the permeability of the 
iron. The figures in the table in italics are the result of taking the 
increased areas, so that a comparison can be made. The D'Arsonval 
galvanometers used have slightly different dead-beatness. The least 
and most dead-beat instrimients were placed in series in the No. 1 
circuit, when the changes of E.M.F. were most rapid. The instruments 
gave the same result within the limits of error in observation. A 
variable still to be dealt with is the wave-form of the magnetising 
currents. 

I wish to express my thanks to Mr. Wm. Marden for the assistance 
he has given mo in the work connected with this paper. Mr. F. S. 
Robertson, Mr. Nunes, and Mr. Browne have also helped me. To 
these gentlemen I tender my thanks. I have also to thank Messrs. 
Elliott Bros, for the loan of three out of the five D'Arsonval galvano- 
meters used in the experiments. The experiments were made at 
King's College, London. 



228 Dr. H. A. Wilson. On the Electrical 

^ On the Electrical Conductivity of Air and Salt Vapours," By 
Harold A. Wilson, D.Sc., M.Sc., B.A., Allen Scholar, Caveii- 
ilish Laboratory, Cambridge. Communicated by Professor 
J. J. Thomson, F.B.S. Eeceived March 14,— Bead March 28, 
1901. 

(Abstract.) 

The experiments described in this paper were undertaken with the 
object of obtaining information on the variation of the conductivity of 
air and of salt vapours with change of temperature, and on the maxi- 
mum current which a definite amount of salt in the form of vapour 
can carry. They are a continuation of the two researches* on the same 
subject published in 1899. 

In the paper on the Electrical Conductivity and Liuninosity of 
Flames {loc. cii.) some observations on the variation of the conductivity 
with the temperature at different heights in the flame are given. 
They indicate a rapid increase in the conductivity with rise of tem- 
perature. 

The method employed in the experiments described in the present 
paper was the following : — 

A current of air containing a small amount of a salt solution in 
suspension in the form of spray was passed through a platinum tube 
heated in a gas furnace ; this tube served as one electrode, and the 
other was fixed iilong its axis. The temperature of the tube was 
measiu-ed by means of a platinum platinum-rhodium thermo-couple, 
and the amomit of salt passing through the tube was estimated by 
collecting the spray in a glass-wool plug. 

From the temperature variation of the conductivity the energy 
required to produce the ionization can be calculated, and this com- 
pared with the energy required to ionize bodies in solutions. 

Since the publication of the researches just referred to, several 
paperst on the conductivity of salt vapours in flames by Dr. E. Marx 
have appeared. The first part of the present paper contains a 
discussion of some of Marx's conclusions, which bear on my previous 
work. 

The rest of the paper is divided into the following sections ; — 

(1.) Description of the apparatus used. 

• " The Electrical Conductivity and Luminosity of Flames containing Vaporised 
Salts," by A. Smithells, H. M. Dawson, and H. A. Wilson, * Phil. Trans.,' A, 1899 ; 
'* On the Electrical Conductivity of Flames containing Salt Vapours," by Harold 
A. Wilson, • Phil. Trans.,* A, 1899. 

t *' Ueber den Potentialfull und die Dissociation in Flammengasen,*' Von Erich 
Marx, * Gesellschaf t der Wissenschaften asu Gdttingen,* 1900, heft 1 ; *. Annalen 
der Physik,' 1900, No. 8. " Ueber das Hairsche Phftnomen in Flammengasen," Von 
E. Marx, * Annalen der Physik,* 1900, No. 8. 



CondudivUy of Air wnd Salt Vapours. 229 

{2,) Variation of the current with the E.M.F. 
(3.) Variation of the current through air with the temperature. 
(4.) Variation of the current through salt vapours with the tem- 
perature. 
(5.) Summary of results. 

The relation between the current and E.M.F. in air was found to 
•depend very much on the direction of the current. When the outer 
•electrode was negative the current attained a satiu'ation value with an 
E.M.F. of about 200 volts, but when the outer tube was positive it 
increased rapidly with the current, even with an E.M.F. of 800 volts, 
480 that a much greater E.M.F. would be necessary to produce satura- 
tion, that is, assuming that saturation can be produced at alL 

With salt vapours the relation between the current and E.M.F. was 
not much affected by reversing the ciu'rent. The current was always 
greater when the outer tube was negative, the reverse being the case 
with air alone. At low temperatiu'es the current attained a saturation 
value, but above 1000** C. it was found to increase more nearly pro- 
portionally to the E.M.F. 

The variation of the current at constant E.M.F. with the temperature 
for air was found to be approximately capable of being represented by 
A formiJa of the type C = A^*, where C is the current, 6 the absolute 
temperature, and A and n constants. The constant n depends on the 
E.M.F. used. With 240 volts it was 17, and with 40 volts 13. The 
•current, therefore, does not begin suddenly when the temperature is 
raised, but always increases regularly with the temperature, so that the 
lowest temperatiu'e at which the current can be detected depends 
entirely on the sensitiveness of the galvanometer. 

The energy required to ionize 1 gramme molecular weight of air was 
estimated by supposing that the fraction of the gas dissociated into ions 
is proportional to the current at small E.M.F's. By means of the 
ordinary thermo-dynamical formula giving the variation of the dissocia- 
tion with the temperature, the energy in question can then be obtained. 
The result for air is 60,000 calories between 1000' and ISOO"* C, This 
amount of energy is of the same order of magnitude as the energy set 
free when H and OH ions combine to form water in a solution. 

The relation between the current and temperature for salt vapours 
was found to be rather complicated. With KI, using an E.M.F. of 
^00 volts, the current had the following values (1 - 10"* ampere) : — 

Temperature 500^ 600^* 700' 800' 900' 1000' 

Current 0-7 1-8 3-0 4-0 4-5 4-0 

Temperature 1100' 1160' 1200' 1300' 

Current 35 3-6 7*0 70 



230 Sir Norman Lockyer. 

Using an £.M.F. of 100 volts, the following yalues of the current 
were obtained (1 =« 10"* ampere) : — 

Temperature 300' 400' 500' eOO"* 700* 800* 

Current 02 19 51 54 5-5 5-5 

Temperature 900** lOOO** 1100** 1200* 1300* 

Current 5-5 53 6-8 8-2 92 

Thus the current has a maximum value near 900* C, and rises very 
rapidly near 1150*. Similar results were obtained with other salts. 

The energy required to ionize 1 gramme molecular weight of KI at 
about 300'' C. was estimated to be 15,000 calories in the same way as 
was done for air. 

The maximum ciurent carried by the salt vapour (at 1300* with 
800 volts) was found to be nearly equal to that required to electrolyse 
the same amount of salt in a solution. 

This fact must be regarded as considerable evidence in favour of 
the xievr that the ions are of the same nature in the two cases. 



" Further Observations on Nova Persei, No. 2." By Sir Norman 
Lockyer, K.C.B., F.RS. Beceived and Bead March 28, 
1901. 

In continuation of two previous papers, I now bring the observations 
of the Nova made at Kensington to midnight oi March 25. Since the 
last paper* of March 7th, estimates of the magnitude of the Nova 
have been made on ten evenings, visual observations of the spectrum on 
eight evenings, and photographs of the spectrum on four evenings up to 
the evening of the 25th. 

In consequence of the greater faintness of the Nova,' the 6-inch 
prismatic camera has not been utilised, but the 10-inch refractor to 
which it is attached has been used for eye observations of the spectnim 
with a McClean spectroscope. 

With the 30-inch reflector foiu* photographs have been secured on 
the evenings of the 6th, 10th, 24th, and 25th by Dr. Lockyer, and with 
the 9-inch prismatic reflector seven photographs on the nights of 10th, 
21st, and 25th by Messrs. Butler and Hodgson. 

Change of Brightness. 

Since March 5th the magnitude of the star has been gradually 
decreasing, but between the nights of the 24th and 25th the light of 

• ^ra^ p. 142. . . 



Further Observations on Nova Perm. 231 

the Nova decreased very suddenly, dropping from 4*2 to 5*5 in twenty- 
four hours, and becoming only just visible as a naked-eye star. 

The following gives a summary of the eye estimates made by 
(1) Dr. Lockyer, (2) Mr. Fowler, and (3) Mr. Butler :— 

(1.) (2.) (3.) 

March 5 2-7 2*7 

6 2-9 — — 

9 — 3-5 3-5 

10 3-7 — — 

11 — — <4-0 

12. — 3-8 — 

21 — 4-0 4-2 

22 _ _1 _ 

23 4-2 4-2 4-5 

24 4-2 4-2 4-5 

25 5-5 5-5 5-5 

(■olour. 

The colour of the Nova has undergone some distinct changes since 
the observation on March 5th last, when it was shining with a clarety- 
red hue. On the 9th and 10th it was observed to be much redder, due 
probably to the great development of the red C line of hydrogen. 

On the 23rd and 24th, the star was noted as yellowish-rod, while on 
the 25th (after the sudden drop in magnitude) it was very red, with, 
perhaps, a yellow tinge. 

The Vmuil Spectrum, 

Since March 5th the spectrum from C to F has become very much 
fainter, the bright lines of hydrogen being relatively more prominent 
than they were before ; indeed, C and F throughout this period have 
been the most conspicuous lines, especially the former, while the bright 
lines XX 5169, 5018, and 4924, and the line in the yellow near D, were 
the most prominent of the others. 

All these lines have been gradually becoming weaker, but there is an 
indication that X 5018* has been brightening relatively to X 5169. 

Accompanying the great diminution in the light of the Nova 
observed on the evening of the 25th, the spectrum was found to have 
undergone a great change : the continuous spectrum had practically 
disappeared, and a line near D (probably helium, D3) became more 
distinct. The other lines were hardly visible. 

* The line near this wave-length in later obseryationB is probabW the chief 
nebular line 5007, which accounts for the apparent brightening ot <^Q\^. 



232 Sir Konnan Lockyer. 

The Photographic Spedrum, 

On March 6th the photographs were very similar to those obtained 
in the earlier stages, the only apparent difference being in the relative 
intensity of the bright hydrogen lines as opposed to those having other 
origins, most of which have been shown to be probably due to iron and 
calcium. The hydrogen lines have sensibly brightened, while the others 
have become much feebler. 

The photograph of March 10th shows a further dimming of the 
bright lines other than those of hydrogen. 

On March 25th, when the next good photograph was taken, the 
spectrum had undergone great modifications. The hydrogen lines are 
still very bright, though they do not show the structure which they did 
in the photographs taken between February 25th and March 10th, 
The bright lines other than those of hydrogen, which are seen in the 
earlier photographs, have now disappeared, and other lines become 
visible. The continuous spectrum has also greatly diminished. 

Approximate determinations of the wave-length of these new lines 
have been made by Mr. Baxandall by comparison with lines of known 
wave-length in the spectra of a and € Persei photographed with the 
same instrument. They are as follows : — 

\ 

3870. Broad, and merging into Hf (3889). 

4367. Weak. 

4472. Not very strong. Probably helium (X 4471-6). 

4565. Weak. 

4650. Very strong broad line. Possibly the 465 line of the bright- 
line stars and the belt stars of Orion. 

4690. Moderately strong. Possibly new hydrogen (X 4687*88) seen 
in bright-line stars and some Orion stars. 

47L Weak. Probably helium (X 4713). 

The hydrogen lines \i} the spectra are Hf, He, H6, Hy, and 11/?. 

The lines at X 3870 and 4650 are perhaps identical vnth those 
obseiTed by von Gothard* in the spectrum of Nova Aurigse after it 
had become nebular, but associated with these lines in his record is the 
chief nebrdar line at 5007, no trace of which is yet visible in the photo- 
graphs of the spectrum of Nova Persei. On the other hand, H^, 
which is the brightest line in the present spectrum of Nova Persei, 
does not appear at all in von Gothard's spectrum of Nova Auriga). 

Characteristics of the Hydrogen Lines. 

In my former paper I referred to the structure of the broad bright 
lines of hydrogen. A more detailed examination of the lines as photo- 

• * A»t..Phj8. Jonr./ vol. 12, 1893, p. 51. 



Farther' Observations on Nova Pei'sei. 



23S 



graphed on several evenings shows that this structure has been under- 
going changes. 

The annexed figure (fig. 1) gives light curves showing the variation 



FEB. £5 



r^ 



MAR. I 



" 3, 




Lj£ooMJIIes. 
I JsftoMilea. 

Fio. 1. — Light curre of H^ (6-inch objectiye prism). 

in the loci of intensity of the line H/3, as photographed with the 6-inch 
prismatic camera. These curves were plotted by Messrs. Baxandall 
and Shaw independently of each other, and I have satisfied myself of 
their accuracy. It will be seen that on February 25th there were three 
points of maximum luminosity, the two maxima on the blue side l>eing 
of equal intensity, and greater than the third on the red side. By 
March 1 the centre one had been greatly reduced in intensity, and on 
the 3rd it had been broken up into two portions, thus making four 
distinct maxima. 

Kough measures made on the relative positions of these points of 
maxima show that the difference of velocity indicated between the two 
external maxima is nearly 1,000 miles per second, while that Vi^Vw^fcXL 



6U 



Further Obeej^caiions mi Nova Pti'seL 



the two inner maxima is 200 per seconcL We thus have indications 
of possible rotations or spiral movements of two distinct sets of 
particles travelling \nth velocities of 500 and 100 miles per second. 

A similar examination of the F and G lines of hydrogen in the 
photographs obtained with the 30-inch reflector has also been made by 
Dr. Lockyer, and the light curves for the G line are here illustrated 
(fig. 2). In this longer series the most important point comes out that 



/n 



PHOTOGRAPHS 



105. 102. 101 



105. 104 



108. 107. 106 



III no. 109 



112 



115 



114 



Fio. 2. — Light, curre of H7 (30-incli reflector). 

the maximum intensity changes from the more to the less refrangible 
side of the bright hydrogen line. 

The small dispersion given by the 30-inch prevents some of the 
details recorded by Messrs. Baxandall and Shaw from ])eing seen. 

80 far as the observations have gone, they strongly support, in my 



Elastic Solids at Best or in Motion in a Liquid. 233 

opinion, the view I put forward in 1877 that " new stars " are produced 
by the clash of meteor-swarms ; and they have suggested some further 
tests of its validity. 

We may hope since observations were made at Harvard and Potsdam 
very near the epoch of maximum brilliancy, that a subsequent complete 
discussion of the results obtained will very largely increase our Isnow- 
ledge. The interesting question arises whether we may not regard the 
changes in spectrum as indicating that the very violent intrusion of the 
denser swarm has been followed by its dissipation, and that its passage 
has produced movements in the sparser swarm which may eventuate in 
a subsequent condensation. 

My best thanks are due to those I have named for assistance in this 
inquiry. 



" Elastic Solids at East or in Motion in a Liquid." By C. Chree, 
Sc.D., LLD., F.R.S. Received November 19,— Read Decem- 
ber 13, 1900. 

§ 1. The problems dealt with in the present paper are probably of 
little practical importance ; but they seem of considerable interest 
from the standpoint of dynamical theory. The hard and fast line 
which it is customary to draw between Rigid Dynamics and Elastic 
Solids has been discarded, and a more direct insight is thus obtained 
into the modes of transmission of force in solids. 

Let us consider a solid of any homogeneous elastic material, possessed 
only of such S3rmmetry of shape as will ensure that if it falls under 
gra\ity in a liquid, each element will move vertically. Take the 
origin of rectangular Cartesian co-ordinates at the centre of gravity, 
the axes of x and y being horizontal, and the axis of z being drawn 
vertically downwards. At time t let C be the depth of the C.G. below 
a horizontal plane in the liquid, the pressure on which is uniform 
and equal to 11. The existence of gaseous pressure on the liquid 
surface would only contribute to n without modif3dng the general 
conditions of the problem. 

Consider first the elementary hydrostatical theory, according to which 
the liquid pressure at any point x, y, z on the surface of the solid acts 
along the normal, and is equal to 

U + gp{(+z), 

where p is the density of the liquid, supposed uniform. 

If the solid fall or rise very slowly, and the viscosity of the liquid 
is very small, the results based on the hydrostatical theory ought to 
give a close approximation to the truth. 

VOL. LXVIJI. ^ 



236 



Dr. C. Chree. 



li a, p, y represent the elastic displacements, xzy xy, &c., the stresses 
in the notation of Todhunter and Pearson's * History of Elasticity,' 
the body stress equations are of the type 

dxx dxv dxz d^a 



dx'^ dy'^'d'z -f 'ta-^' 



dx^ dy^ dz~ f* 'i»~^' 



dt' 



(1); 



dxz dyz dzz f a^(k + v)T 

where p represents the density of the solid, g the acceleration of 
gravity. 

The equations treat t, y, z as constants for each element of the 
solid, and so assume that the motion, if motion takes place, is 
purely translational. 

If A, /i, V be the direction cosines of the outwcardly directed normcal 
at a point x, //, z, the surface equations are 

(\xx + fij:y + vxz)/k = (^y + Myy + vv/^*)//* = {krz-\-fjit/z + i'Zz)lv 

= -U-gp'{C+z) '. (2). 



The equations (2) are satisfied by the assumption 

X1J = xz =^ yz = 
Also the values (3) satisfy the body stress equations (1), pro\'ided 



} 



(3). 






dp 



= 0, 



^"-^it^^-4 = -■'"' (^>- 



We can satisfy (4) by assuming 
dp " ' 



C = const. +yPzPr- 
p 



(5). 



For brevity, the constant in (5) will be supposed to be zero. 

The result (5) is of course that given by ordinary elementary 
methods for the accelerated motion of a solid rising or falling in a 
liquid of different density. 



Elastic Solids at Best or in Motion in a Liquid. 



237 



On looking more closely into the matter an inconsistency manifests 
itself. Supposing for mathematical simplicity that the solid is 
isotropic, of bulk modulus h, we find that the displacements answer- 
ing to (3) are given by 



y - -\nz + gp'{z{i:^-z)-l{3?+y' 



i« + *»)}]/3AJ 



(6). 



The inconsistency consists in the fact that, by (6), a, /?, y contain 
terms in ^, and so by (5) terms in f^ while above it was assumed 
that (Pa,jd£^, <fec., vanished. It thus appears that the solution embodied 
in (3) and (6) is valid and complete only when ( does not vary as f^, 
i.e,f only when the solid is at rest or moving with uniform velocity in 
the liquid. 

Though thus restricted, the solution is notable from its simplicity 
and generality, as applicable to any homogeneous solid (free from 
cavities) at rest in a liquid of equal density. 

The values (3) for the stresses apply irrespective of the species of 
elasticity. The displacements are given by (6) only when the material 
is isotropic, but corresponding expressions are immediately obtainable 
for materials of greater complexity. If for instance we have material 
symmetrical with respect to the co-ordinate planes, we have 



/3= -y{n + i7p'(f+2r)}(l-i72i->723)/E2, 
7- -i8r{n + i7/>'(f+i^)}(l-i78i-'?32)/Es 

+ i5'P'|^(l -^2- Vn) + |-(1 -^2i->/23)| 



(7). 



Here Ei, E2, E3 are the three principal Yoiuig's moduli, while 
V\^i V1Z9 &c., are the corresponding Poisson's ratios. 

§ 2. Presently we shall consider the equilibrium problem in greater 
detail. Meanwhile, in the case of uniformly accelerated motion, we 
shall obtain a self-consistent solution for a sphere, or any form of solid 
ellipsoid, under the conditions assumed in § 1. 

The procedure to be adopted is the same for all species of elastic 
material. If for definiteness we suppose the material symmetrical with 
respect to the three co-ordinate planes, we first assume that the 
stresses (3) and displacements (7) form part — but only part — of the 
complete solution, ( being given by (5). Then substituting from (7) 
in the body stress equations (1), we find that the stresses of the 
suppleineTUdry solution, as we may call it, must satisfy 



238 



Dr. C. Chree. 



where 



(^ dxif chiz ^ 

dzz dyz dzz _ 



(8); 



Pp = g-p(p - p')(l - iyi2 - t;i3)/Ei , ' 

(ip = gY(p-p)(l-V2i-v^)l^., ^ (9i. 

Rp = ^y (p _ p') (1 - ,^31 - i;32)/E3 ^ 

The surface equations to be satisfied by the supplementary solution 
are 

Xxx + fJLXf/ + v7:z = ^y + P'yy + yy^ = ^z-k-iiyz-k-vzz = 0... (10). 

The problem thus resolves itself into that of an ellipsoid acted on 
solely by bodily forces derivable from the potential 

i(P^- + Q/ + R^2). 

This problem was solved by me in 1894 for isotropic* materials, and 
in 1899 I extended the solution to seolotropict ellipsoids. We can 
thus derive a satisfactory supplementary solution from the sources 
specified. Finally adding the stresses of the supplementary solution 
to the stresses (3), and the displacements to the displacements (7), we 
have a consistent and complete solution of the problem presented by 
a heavy ellipsoid in a homogeneous liquid, when the action of the 
liquid is supposed that given by elementary hydrostatics. 

§ 3. The supplementary solution, though simple in t)^e, contains 
terms which are of great length when the ellipsoid has .three unequal 
axes, and is of a complex kind of seolotropy. It will thus perhaps 
suffice to select for illustration the simple case of an isotropic sphere of 
radius a. 

Denoting Young's modulus by E, Poisson's ratio by ?/, and \\Titing 
r- for a;2 + y2 ^ ^i^ ^q \^yq in full 



• *Roy. Soc. Proc.,' toI. 68, p. 39; * Quarterly Journal of Pure aud Applied 
Mathematics/ vol. 27, p. 338. 
f 'Comb, Phil Soc. Trans.,* vol. 17, p. 201, 



Elastic Solids at Best or in Motion in a Liquid. 



239 



p 

.^= -n-gp'iz+ye^t^) 

p 
p 



^yjxy = xzjxz = yzjyz = - jrV(p - p')(l - 2»,)''-;- {5E(1 - r,)} 
a/a « ^/y 



(11); 



.li^{n^gp-(z^ytz^i^) 



1-2^ 



-'-^i^";;*«»-')'"-<'*')-i. 



p-/> 



(12). 



The terms in ^^ constitute what has been called above the supple- 
mentary solution. In the case alike of the stresses and of the dis- 
placements they are exactly the same ds if the sphere were imder a 
self-gravitative force which followed the ordinary gravitational law, 
and which had for its accelerative value at the surface of the sphere 

-p E""^- 

This imaginary gra^dtative action represents attraction or repulsion 
between elements of the solid according aa p-p is negative or posi- 
tive. It is thus an attraction when the sphere rises in a heavier liquid, 
a repulsion when it sinks in a lighter. The smaller 1 - 2r), or in 
general the less compressible the solid, the smaller is the effect of this 
imaginary gravitative force relative to that of the hydrostatic pressure 
n + gp{^+0> o^ ^^® other hand its relative importance increases 
rapidly with the size of the sphere. 

Representing by dashed letters the parts of the displacements 
depending on p - p\ we have 



240 Dr. C. Chree. 

a'lx - Ply = ilz 

At the very banning of the motion, the ezpressioii indde the square 
bracket is positive for all values of r; but as i increases it changes 
sign, first at the surface, last close to the centre of the sphere. If {«> 
Co represent the distances fallen when the expression vanishes at the 
surface and at the centre respectively, we have 



t./a-(l-i,)yO»-/.>/lM.- 
&/« - {3-v)9(p-p')a/30k 



■} 



Unless a is enormously large, (« and (o must be extremely small for 
any ordinary elastic material. 

In reality, in order to be instantaneously at rest, the sphere would 
require to be supported or acted on by some suddenly suppressed force, 
or to be in the act of reversing some previously impressed motion. 
The elastic strains and stresses might initially retain the impress of 
the pre-existing state of matters, and there are thus special sources of 
uncertainty affecting the applicability of (14) to actual conditions, 
which should not be lost sight of. 

§ 4. The problem just considered has been advanced as showing bow 
imder a consistent dynamical system, producing uniform acceleration 
in a straight line, there appear elastic strains and stresses which simu- 
late the action of self-gravitation in the material in motion. The 
conditions postulated do not answer exactly to what happens when a 
real solid moves through real liquid at the earth's surface. Under 
such circimistances the action between solid and liquid is not fully 
represented by the hydrostatic pressure. If the fluid be "perfect," 
ordinary hydrodynamical theory^ gives for the pressure p on the 
surface of the sphere, supposing u the velocity, 

p - U + gpX(+z) + p\iauFi + iu^T2-lu*) (15), 

where Pi, P2 are zonal harmonics, whose axis is the vertical diameter. 
We shall now consider this case, on the hypothesis that the velocity is 
so small that terms in u> are negligible. Instead of (3) and (6) we 
find for the stresses and displacements, the material being supposed 
isotropic, 

S = yy - S = -n-^p'(C+^)"-iV^il 

^ ^ ^ > (16); 

xy *» zz » yz =i J 

• Cf, Lamb's ' Hjdrodynmmicf/ Art. 91. 



Elastic Solids at Best or in Motion in a Liquid. 241 



l-2i? 



K 



[II«+(7/>X+J/>'0^+Ju)(«« x«-y»)] 



(17). 



.(18). 



Instead of (4) we have 

Also u = d'Cldf', 

thus, if d^/dP be omitted, we have 

(^ + i/'')0=<7(p-A 

or f = constant + if/ ^^^Z- 

P + iP 

This is, of course, only the well-known result, that the dynamical 
action of the liquid may be regarded as adding to the mass of the 
sphere that of a hemisphere of the liquid.* We may suppose the con- 
stant in (18) to be zero, suitably interpreting IT. 

As in the first case considered, the existence of /^ in C and, conse- 
quently, in a, P, y, makes a supplementary solution necessary. The 
stresses of the supplementary solution must satisfy the surface equa- 
tions (10) as well as the following body stress equations : 

.d^. dxy d7z\ I (d7y d^j d^z\ / 

_ (d^ dyz d7z\ I ^ __ 1-27; 2gypjipj-p) ,,g\ 

'^ ['dx^l^^l^J/ ^ ^ ""E~" 2p + p'' ^ ^' 

It will be observed that the retention of the term in u in the pres- 
sure has only modified (reduced) the acceleration without altering the 
type of the supplementary solution. It will thus suffice to record the 
complete expressions for the displacements, viz.. 



T^'[n'-.(0?7)<''-"-'')-«'|fe^^ 



(20)-. 



• Cf. Lamb's 'Hydrodynamics/ Art. 91; or BaiseCa ^Ttea.^* oii. 'Bi^^^- 
Hynamics,' Art. 182. 



242 



Dr. C. Chree. 



In obtaining this solution we have neglected terms in u^ t.^., terms 
in (dCjdty or g^fi{p - />')*/(p + i/>')^ in the expression (15), while there 
appear in the solution terms containing ^^ - />')/(2/> + />')• Thus 
our work is consistent only when (/» - p)/p is small, and even when 
this is the case the fact that ti^ increases as P involves a restriction 
which should not be overlooked. It would not, I think, be a very 
difficult matter to obtain a complete solution answering to the full 
value (15) of p. Treating u^ at first as a constant, we could at once 
write down, from my general solution* for the isotropic elastic sphere, 
the displacements answering to the surface pressure ipV(3Ps - 1) ; 
but the explicit determination of the corresponding supplementary 
solution would be much more laborious than in the first case treated 
above. 

§ 5. When p' and /> are equal, and u' is thus really constant, the 
complete values of the stresses and displacements answering to the 
surface pressure (15) are as follows : — 



XX 



-n 



•gp\z + ut)-^ip'u^ + -P^[{7-^2rj)a^ 



(21); 



+ 3i;(5a:« + y3)-3(7 + 6iy)^«], 

?z= 'n^gp'(z-^ui) + ip'u^-^P^[2{7 + 2rj)a^ 

-3(7 + v)(^^ + y^) + 6iy^], 
xy = - 9pu^rixya-^ ^ [2 (7 + 5t;)], 
xz/iz = ^/yz = VuV"*-^[4(7 + 5v)] 
a/x = Ply = ^h^[n^ip'u^ + gp\z + ut)] 

+ t^^-]^^[(7 + 2v)a«-6i,(x2 + jr^) ~3(7~8^).^, 

r= -^-^[(n-ipV)^+i7PW^+i(^^-^^-y=)}] 

§ 6. In real liquids viscosity is more or less present, and as the 
hydrodynamical equations have been solved for the case of an ellipsoid 

• * Ounb. Phil. 8oo. Tniu.,* toI. 14, p. 260. 



(22). 



Elastic Solids at Beat or in Motion in a Liquid. 



243 



^hen the retarding action of viscosity neutralises the acceleration due 
to gravity, it is worth considering. The hydrodynamical solution 
really assumes the velocity to be small, and the ellipsoid to be so 
remote from the surface and other boimdaries as to be practically in an 
infinite liquid. 

It is not very diflficult to deduce from the formiilse in Lamb's 
* Hydrodynamics,' Art. 296, — though I have not seen the result noticed 
— that the viscous surface action reduces to a force fvr per imit surface, 
opposite to the direction of motion, w being the perpendicular from the 
centre on the tangent plane, and / a constant. The recognition of 
this fact saves us from the labour of considering the general expressions 
for the hydrodynamical pressures, which are of a very complicated 
nature. 

As the motion is steady, the body stress equations are 

dZ (£y dxz dTij djy dlfz dxz dyz tizz , , 

dx^'dy^-^ ^ -B^'dy^^dz ^-dJ^^dy^dz^^f'^^"'^^^^' 

while the surface equations are — (r, 6, c being the semi-axes of the 
ellipsoid — 

a-'xxx + h-'yxy-\'c-'zxz = ^a'^x{U.'\-gp\i-{-z)}, " 

a-^xTy + h-'-y^j + c-'h^z = -b'^-yiU + gp^C+z)}, ^(24). 

a--xxz-{-h--yyz + C''^xzz = -c~2^{n + ^p(f+-r)} -/ 

The surface equations are satisfied by 

S= ^U^gp'(C+^) + {a'l(^)fz, 

^= -ri-/7p'(f+0-A r (25)- 

xy = 0, 

^zjx = yijy = -/ 

The values (25) also satisfy the body stress equations (23), pro- 
vided 

-3/+i7(p-p)= (26). 



As 



[j/irdS = 3/.$7ra&f, 



when the integral is taken over the surface of the ellipsoid, (26) is 
simply equivalent to the condition that the motion is not accelerated, 
or that 

( = «/. 



244 



Dr. C. Chree. 



where u is « constant. As to the value of t», it has been proved that 
the total viscoiis resistance to the motion is* 

16ir/A't«a6c/(xo + c*ro)» 
where /a' is the viscosity, and 

Xo = a6c ["[(a* + X) (ftt + X) (c« + X)]-«X, 
7o=a6c|J[(a« + X)(6* + X)(c2 + X)»]-»dX. 

But this resistance is also equal to g(p - p)^irabe [or to I l/rcfiS], 

thus 

u - y0>-p)(xo + c»yo)/12/i'. 

Substituting for ( and/ in (25), we have 

S = - n - gp{s + ui)-\-y{p- p') a^z/c\ 

S=: 'n-gp\z-^ut)-y{p-p')z, • (27). 

«y = 0, 

The corresponding displacements, supposing the material isotropic, 
are 



6E v"^^"^; 



6E 



[4.a,.2!^).W2.3„.5^)] 



(28). 



§ 7. The terms inside the first brackets in (28) contain II or gp\ and 
represent displacements which vary only with the depth of the element 
or its distance from the centre of the ellfpsoid. The terms containing 

* Cf. Lamb's < Hjdrodjnamios/ Art. 296. 



Maslie Solids at Best or in Motion in a Idquid. 



245 



g{p - p), on the other hand, depend largely on the shape of the 
ellipsoid. 

Thus, denoting them by a', )8', y, we have approximately, in the 
case of a very elongated ellipsoid, whose long axis is vertical, 






'«)]/6E J 



.(29); 



and, except' in the immediate vicinity of the central section 2 = 0, we 
may take in place of (29) 



a'/zn - ^lyn = -y'liiz) - g{p-p')zlSE.. 



(30). 



In a very flat ellipsoid, approximating to a disc, with the short axis 
vertical, we have approximately 

a' = g{p-p')xz(a^-'qh^)l{Z^% 

^ -^g{P' P)yz{h^ - ^a2)/(3Ec2), . (31). 

y' = -gip- p) [(a^ - '/i'-)^- + (^= - ';«')y^ +>;(«' + ^y^] ■^ (SEc^) 

Except close to the vertical diameter, the terms in z^ in y would be 
relatively negligible, while, in general, a! and /J' would be small com- 
pared to y. 

In the case of the sphere it is perhaps more convenient to record the 
complete solution, \\z., 

S = ^ = -'ll-gp%U'^\g{p-^p)z, 

zz = 'Tll-gput-lg{p + 2p)z, 

xy = 0, 

S/^ = F/y = 'lg{p'P) 

-^-^^[(3 + 2r;)(a;2 + y2)+(l + 2^)^2] 



.(32); 



...(33). 



[3/arcA 13, 1901.] — The paper as originally presented to the Society 
dealt briefly with two or three other details. It showed how the solu- 
tion in § 6 depended not on the viscous resistance varying as the first 
power of the velocity in the final state, but on its vat^irv^ wet >iJt^^ 



246 Mr. J. K Petavel. On the Beat dissipated 

surface as the perpendicular on the tangent plane. In particular, if, in 
accordance with Mr. Allen's experiments,* there be possible forms of 
final uniform motion for a sphere in which the resistance varies as 
ul or u^ {u being the velocity), it was shown that the solution would 
still be of the form of (32) and (33), provided the distiibution of the 
viscous resistance happens to remain unchanged. 

It was pointed out that in an isotropic solid, free of cavities, at rest 
in a liquid, the stresses are everywhere the same as if each element 
were separately subjected to the pressure answering to its depth ; but 
that when cavities exist in the solid the state of matters is altered. As 
an example, a complete solution was given for a hollow spherical shell 
fully immersed. 

It was shown that, in a completely solid body, the greatest strain 
and maximum stress-difference theories agreed in indicating no ten- 
dency to rupture, but that when cavities existed, it was otherwise ; in 
particular, that in the spherical shell there is on either theory a 
tendency to rupture, greatest at the lowest point, which approximately 
in a thin shell varies directly as the depth and inversely ^s the thick- 
ness of the shell. 



" On the Heat dissipated by a Platinum Surface at High Tempera- 
tures. Part IV.t— High-pressure (^ases." By J. E. Petavel, 
A.M.I.C.K, A.M.I.E.E., John Harling Fellow of Owens 
College, Manchester. Conmiunicated by Professor Schuster, 
F.RS. Eeceived February 7,— Read March 7, 1901. 

(Abstract.) 

The rate of cooling of a hot body in gases at pressures up to one 
atmosphere has received considerable attention, but with regard to 
gases at high pressures practically no data were up to the present 
available. It was thought therefore that an experimental investigation 
of the subject might prove of some interest. 

The experiments were carried out with a horizontal cylindrical 
radiator contained in a strong steel enclosure, the enclosure being 
maintained at about IS** C. by a water circulation. 

It is shown that the rate at which heat is dissipated by the radiator 
may be expressed by the following formula — 

E = rt/>* •¥ hpfi^, 

where E = cmissivity in C.G.S. units = total amount of heat dissi- 

• * Phil. Mag.,' September and November, 1900. 

t For Parts I, II and IH see * Phil., Trans.,' A, toI. ]91, p. 601, 1898. 



hy a Platinum Surface at High Temperatures. 



247 



pated expressed in therms (water-grammes-degrees) per square centi- 
metre of surface of radiator per second, 

p = pressure in atmospheres, 

.9 = the temperature of the radiator minus the temperature of the 
enclosure, or in other words the temperature interval in degrees 
Centigrade. 

The limits between which the formula may be considered to hold 
good, and the numerical value of the constants for the various gases 
studied, are given by the following table : — 



1 


a X 10«. 


h X 10». 


a. 


P> 


The formula holds good 


1 


from 


to 


and 
from 
P - 


to 
P- 


Air 


403 

387 

2705 

276 

207 


1-68 
1-39 
1-88 
1-70 
1-60 


0-56 
0-68 
0-36 
0-74 
0-82 


0-21 
0*28 
0-86 
0-28 
0-33 


100 
100 
300 
100 
100 


1100 
IICO 
1100 
800 
1100 


7 

15 

7 

6 

10 


170 

115 

113 

40 

35 1 


! Oxygen 

1 Hydrogen 

1 Nitrous oxide.. 
Carbon dioxide. 



The question as to what proportion of the total loss of heat is due 
respectively to convection, conduction, and radiation is treated at some 
length. The influence of experimental conditions, such as the tem- 
perature of the gas and the dimensions of the radiator and enclosure, 
is also studied. 

All gases show a rapid increase of the effective conductivity with 
the pressure. In air, for instance, the rate of cooling is six times 
greater at 100 atmospheres than it is at atmospheric pressure. The 
effect of the high rate at which heat is transmitted through compressed 
gases is discussed, both from a theoretical and a practical point of 
view, and the bearing of the results on some problems of modem 
engineering is considered. 



248 



Prof. G. H. Darwin. 



May 2, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, in the (3hair. 

A List of the Presents received was laid on the table, and thanks 
ordered for them. 

In pursiiance of the Statutes, the names of the Candidates recom- 
mended for election into the Society were read, as follows : — 



Alcock, Professor Alfred William, 

M.B. 
Dyson, Frank Watson, M.A. 
Evans, Arthur John, M.A. 
Gregory, Professor John Walter, 

D,Sc. 
Jackson, Henry Bradwardine, 

Captain, K.N. 
Macdonald, Hector Munro, M.A. 
Mansergh, James, M.Itist.C.E. 



Martin, Prof. Charles James, M.B. 

Ross, Bonald, Major (I.M.S., re- 
tired), 

Schlich, Professor William, C.I j;. 

Smithells, Professor Arthur, B.Sc. 

Thomas, Michael R Oldfiold, F.Z.S. 

Watson, William, B.Sc. 

Whetham, William C. Dampier, 
M.A. 

Woodward, Arthur Smith, F.G.S. 



The following Papers were read : — 

I. "On the Variation in Gradation of a Developed Photographic 
Image when impressed by Monochromatic Light of different 
Wave-lengths." By Sir W. de W. Abxey, K.C.B., F.R.S. 

II. " Ellipsoidal Harmonic Analysis." By G. H. Darwix, F.R.S. 

III. " On the Small Vertical Movements of a Stone laid on the Surface 
of the Groimd." By Horace Darwix. Commimicated by 
Clement Reid, F.RS. 



** Ellipsoidal Harmonic Analysis." Hy G. H. Darwix, F.R.S., 
Plumian Professor and Fellow of Trinity College in the 
University of Cambridge. Received March 23, — Read May 2, 
1901. 

(Abstract.) 

Lamp's functions have l>een used in many investigations, but the 
form in which they have been presented has always been such as to 
render numerical calculation so difficult as to be practically impossible. 
The object of this paper is to remove the imperiection in question by 



Ellipsoidal Harmonic Analysis, 249 

giving to the functions such forms as shall render numerical results 
accessible. 

Throughout the work I have enjoyed the immense advantage of 
frequent discussions with Mr. E. W. Hobson, and I have to thank him 
not only for many valuable suggestions but also for assistance in 
obtaining various specific results. 

My object in attacking this problem was the hope of being thereby 
enabled to obtain exact numerical results as to M. Poincar^'s pear- 
shaped figure of equilibrium of rotating liquid. But it soon became 
clear that partial investigation with one particular object in view was 
impracticable, and I was led on to cover the whole field, leaving the 
consideration of the particular problem to some future occasion. 

The usual symmetrical forms of the three functions whose product is 
a solid ellipsoidal harmonic are such as to render purely analytical 
investigations both elegant and convenient. But it seemed that 
facility for comjiutation might be gained by the surrender of sym- 
metry, and this idea is followed out in the paper. 

The success attained in the use of spheroidal analysis suggested 
that it should be taken as the point of departure for the treatment 
of ellipsoids with three unequal axes. In spheroidal harmonics we 
start with a fundamental prolate ellipsoid of revolution, with imaginary 
semi-axes k J -I, k J -l, 0, The position of a point is then defined 
by three co-ordinates ; the first of these, r, is such that its reciprocal is 
the eccentricity of a meridional section of an ellipsoid confocal with 
the fundamental ellipsoid and passing through the point. Since that 
eccentricity diminishes as we recede from the origin, v plays the 
part of a reciprocal to the radius vector. The second co-ordinate, /i, 
is the cosine of the auxiliary angle in the meridional ellipse measured 
from the axis of symmetry. It therefore plays the part of sine of 
latitude. The third co-ordinate is simply the longitude <f>. The 
three co-ordinates may then be described as the radial, latitudinal, 
and longitudinal co-ordinates. The parameter k defines the absolute 
scale on which the figure is drawn. 

It is equally possible to start with a fundamental oblate ellipsoid 
with real semi axes k, ky 0. We should then take the first co-ordinate, 
f, as such that ^ = --v-. All that follows would then be equally 
applicable ; but in order not to complicate the statement by continual 
reference to alternate forms, the first form is taken as a standard. 

In the paper a closely parallel notation is adopted for the ellipsoid 
of three unequal axes. The squares of the semi-axes of the funda- 
mental ellipsoid are taken to be - ^^f™J, - k-, 0, and the three 

co-ordinates are still v, fi^ 4>, As before, we might equally well start 
with a fundamental ellipsoid whose squares of semi-axes are 

k^l±^, k\ 0, and replace v* by i« where {2=. -y^. K)i\ ^^^^'fc 



250 Prof. G. H. Darwin. 

ellipsoids are comprised in either of these types by making )3 vary 
from zero to infinity. But it is shown that, by a proper choice of tjrpe, 
all possible ellipsoids are comprised in a range of P from zero to one- 
third. When P is zero we have the spheroids for which harmonic 
analysis already exists, and when P is equal to one-third the ellipsoid 
is such that the mean axis is the square root of mean square of the 
extreme axes. We may then regard P as essentially not greater than 
one-third, and may conveniently make developments in powers of j8. 

In spheroidal analysis, for space internal to an ellipsoid I'o, two of 
the three functions are the same P-functions that occurs in spherical 
analysis ; one P being a fimction of v, the other of ft. The third 
function is a cosine or sine of a multiple of the longitude <^. For 
external space the P-function of i^ is replaced by a Qfimction, being 
a solution of the differential equation of the second kind. 

The like is true in ellipsoidal analysis, and we have P- and Q-func- 
tions of V for internal and external space, a P-fimction of /a, and a 
cosine- or sine-function of <t>. For the moment we will only consider 
the P-fimctions, and will consider the Q-f unctions later. 

There are eight cases which are determined by the evenness or 
oddness of the degree i and of the order s of the harmonic, and by 
the alternative of whether they correspond with a cosine- or sine- 
function of <f>. These eight types are indicated by the initials E, O, 
C, or S ; for example, EOS means the type in which i is even, s is odd, 
and that there is association with a sine-function. 

It appears that the new P-functions have two forms. The first form, 
written 5P, is foimd to be expressible in a finite series in terms of 
P'^^j when the P's are ordinary functions of spherical analysis. The 
terms in this series are arranged in powers of jS, so that the coefficient 
of P/±2x. hag ^k ag part of its coefficient. The second form, written 

P-, is such that a/--o«.- P'W*"- a/ ..^"^1 P''('^) 

expressible by a series of the same form as that forj^'. Amongst 
the eight types four involve 5P-functions and four P-functions ; and if 
for given s a 5P,*-fnnction is associated with a cosine-function, the 
corresponding P, is associated with a sine-function, and tire versd. 

Lastly, a 5P-function of v is always associated with a 5P-function of 
fi ; and the like is true of the P's. 

Again, the cosine- and sine-functions have two forms. In the first 
form 8 and i are either both odd or both even, and the function written 
C' or i&i* is expressed by a series of terms consisting of a coefficient 
multiplied by j8* cos or sin {s ± 2k)it>, In the second form, s and i 
differ as to evenness and oddness, and the function written C* or Si 
is expressed by a similar series multiplied by (1 - j8 cos 2<^)*. 

The combination of the two forms of P-function with the four forms 
* coeine- and sine-function gives the eight types of harmonic. 



13 



Ellipsoidal Harmonic Analysis, 251 

Corresponding to the two forms of P-function there are two forms 
of Q-f unction, such that (Qi* and Q^' ^ / ^ "" are expres-sible 

in a series of ordinary Q-f unctions ; but whereas the series for Jp; and 
P/ are terminable, because P/ vanishes when s is greater than /, this 
is not the case with the Q-f unctions. 

In spherical and spheroidal analysis the differential equation 
satisfied by P,* involves the integer s, whereby the order is specified. 
So here also the differential equations, satisfied by 5P/ or P/ and by 
C/, ^ •, Cj", or S,*, involve a constant ; but it is no longer an integer. 
It seemed convenient to assume 5=^ - /So- as the form for this constant, 
where s is the known integer specifying the order of harmonic, and 
(T remains to be determined from the differential equations. 

When the assumed forms for the P-function and for the cosine- and 
sine-functions are substituted in the differential equations, it is found 
that, in order to satisfy the equations, )8«r must be equal to the 
difference between two finite continued fractions, each of which 
involves )8<r. We thus have an equation for j3<r, and the required root 
is that which vanishes when j8 vanishes. 

For the harmonics of degrees 0, 1, 2, 3 and for all orders <r may }yQ 
found rigorously in algebraic form, but for higher degrees the equation 
can only be solved approximately, unless j8 should have a definite 
niunerical value. 

When jScr has been determined either rigorously or approximately, 
the successive coefficients of the series are determinable in such a way 
that the ratio of each coefficient to the preceding one is expressed by 
a continued fraction, which is in fact portion of one of the two frac- 
tions involved in the equation for j8<r. 

Throughout the rest of the paper the greater part of the work is 
carried out with approximate forms, and, although it would be easy to 
attain to greater accuracy, it seemed sufficient in the first instance to 
limit the development to P^, With this limitation the coefficients of 
the series assume simple forms, and we thus have definite, if approxi- 
mate, expressions for all the functions which can occur in ellipsoidal 
analysis. 

In rigorous expressions 5P* antl P/are essentially different from 
one another, but in approximate forms, when s is greater than a 
certain integer dependent on the degree of approximation, the two 
are the same thing in different shapes, except as to a constant factor. 

The factor whereby P/ is convertible into 5P/> aiid C/ or S' into 
C/ or ^; are therefore determined up to squares of j8. With the 
degree of approximation adopted there is no factor for converting the 
P's when 5 = 3, 2, 1. Similarly, down to 5 = 3 inclusive, the same 
factor serves for converting C* into C/ and S/ into ^/. But for 
.s- = 2, 1, one form is needed for changing C iivU> C».w\ ^wQ\>RSjt 

VOL. LXVIII. 1 



252 JBU^midal HdrmaniG Analysis. 

for changing 8 into A. It may be well to note that there is no sine- 
function when 8 is xero. 

The use of these factors does much to facilitate the laborious reduo- 
tions involved in the whole investigation. 

It is well known that the Q-functions are ezpressibie in terms of the 
P-functions by means of a definite integral. Hence <S/ and Q/ must 
have a second form, which can only differ from the other by a con- 
stant factor. The factor in question is determined in the paper. 

It is easy to form a function continuous at the surface vo which 
shall be a solid harmonic both for external and for internal space. 
Poisson's equation then gives the surface density of which this con- 
tinuous function is the potential, and it is found to be a surface 
harmonic of /a, ^ multiplied by the perpendicular on to the tangent 
plane. 

This result may obviously be employed in determining the potential 
- of an harmcmic deformation of a solid ellipsoid. 

The potential of the solid ellipsoid itself may be found by the con- 
sideration that it is externally equal to that of a focaloid shell of the 
same mass. It appears that in order to express the equivalent surface 
density in surface harmonics it is only necessary to express the 
reciprocal of the square of the perpendicular on to the tangent plane in 
that form. This result is attained by expressing «2, y^, z^ in surface 
harmonics. When this is done an application of the preceding theorem 
enables us to write down the external potential of the solid ellipsoid 
at once. 

Since ic-f y^, z^ have been found in surface harmonics, we can also 
write down a rotation potential about any one of the three axes in the 
same form. 

The internal potential of a solid ellipsoid does not lend itself well to 
elliptic co-ordinates, but expressions for it are given. 

If it be desired to express any arbitrary function of /a, <^ in surface 
harmonics, it is necessary to know the integrals, over the surface of 
the ellipsoid, of the squares of the several surface harmonics, each 
multiplied by the perpendicular on to the tangent plane. The rest of 
the paper is devoted to the evaluation of these integrals. No attempt 
is made to carry the developments beyond P^, although the methods 
employed would render it possible to do so. 

The necessary analysis is difficult, but the results for all orders and 
degrees are finally obtained. 



Small Vertical Movements of a Stogie on tfce Grou)id. 253 

" On the Small Vertical Movements of a Stone laid on the Smface 
of the Ground." By Horace Darwin. Communicated by 
Clement Beid, F.RS. Eeceived April 17, — Read May 2, 
1901. 

In my father's book on Vegetable Mould and Earthworms an esti 
mate is given of the rate at which stones placed on the surface of the 
soil are bmied by the action of earthworms. The estimate is rough, 
and as far as I know no attempt has been made to detect such move- 
ments when small, or to determine them accurately when they are 
large. 

The experiments described in this paper were undertaken originally 
to measure accurately the downward movement of a stone caused by 
earthworms. The upward and downward movements due to varying 
moistiu*e of the soil and to frost were found to be much larger than 
was expected. These movements, interesting in themselves, increase 
the difficulty of accurately determining the movement due to the 
action of earthworms.* 

The experiment was begun on September 5, 1877, and the position 
selected is in a nearly level field which had probably been pasture for 
considerably more than fifty years. It is to the south of my father's 
house at Down, close to some railings separating the field from the 
lawn and under a large Spanish chestnut tree. He approved at the 
time of the selection of this position ; at a later date he considered a 
mistake had been made, as he thought there were fewer worms under 
trees, t 

It was necessary to have a fixed point from which the displacement 
might be measiu^ed ; this was managed in the following way : — An 
iron rod was driven into the ground by means of a heavy hammer ; it 
was then removed, and a copper rod, slightly larger (22 mm. in 
diameter), was driven into the hole ; the bottom of the rod was about 
2-63 metres from the surface. The top of this rod is the point from 
which all measurements were taken.* 

A circular stone about 460 mm. in diameter and about 57 mm. thick, 
weighing about 23 kilos., was placed on the ground with the rod pro- 
jecting through a hole in its centre. A brass cylinder, slightly smaller 
than the hole in the stone, had previously been firmly fixed in the 
hole by running in melted lead. The brass cylinder had three pro- 
jecting pieces at its top ; three symmetrical radial right-angle grooves 
were cut, one in each of these projecting pieces. This gave the usual 

• See * Vegetable Mould and Earthwomw,' by C. Darwin, 1883, p. 121, where a 
sliort preliminarj account of the experiment Ib giyen« 

t Ibid., p. 146. In Knowle Park, under beech trees, worm eastings were «i\&XMX> 
wholly absent. 

t *1 



254 Mr. H. Darwin. On the Small Vertical Movements 

form of geometrical bearings for the three rounded feet of the stand 
which carried the micrometer used for measuring the relative positions 
of the stone and the top of rod. 

The action of the earthworms woiJd cause the stone to sink rela- 
tively to the top of the rod, but the following other causes should also 
be considered : — 

1. The Growth of the Roots of the Tree, — The copper rod passed 
through about 2*63 metres of slightly sandy red clay which overlies 
the chalk, and contains many flints ; some of these were broken or 
displaced by the passage of the iron rod. Great force was required to 
draw the rod out of the ground, and in doing so its sides became 
scored by the flints. It is, therefore, safe to assume that the flints 
were pressed with considerable force against the rod, and that their 
sharp edges gripped it tightly. The point where the rod was gripped, 
and where there was no relative movement between it and the clay, was 
unknown ; probably, however, it was well below the level of the roots 
of the tree. The roots growing larger in diameter would raise the 
stone relatively to the top of the rod. The amount of this movement 
is quite uncertain. 

2. Dampness of the Grouwi. — The clay and the surface soil both, no 
doubt, swell with increase of moisture. The swelling of the clay 
above the unknown point at which the rod is gi-ipped will raise the 
stone, and the swelling of the surface soil will have the same eff'ect. 

3. Expansion of the Hod from Change of Temperature, — The effect of 
this is very small and is quite negligible when measurements, taken at 
the same time of year, are compared. If we take a high estimate 
and assume that the summer and winter temperature of the rod 
differed by 10^ C, the relative movement of the stone and the top 
of the rod would be about 0*4 mm. ; this is on the assumption that 
the rod is only gripped close to its lower end, and that the expansion 
practically of its whole length is taken into account. An attempt 
was made to eliminate this error by sinking two rods alongside of 
each other, one being of iron and one of copper, and by taking 
measiu*ements from both rods. This attempt failed, and the results 
now given are the measiu'ements from the copper rod only.* 

The raeasiuing apparatus is shown in fig. 1. It consists of a brass 
ring A, with three short rounded feet B, which rest in the radial 
grooves before mentioned. This annular base carries a vertical brass 
rod C, to which is soldered an arm with V-beariiigs D. Trunnions E 
were fixed to the usual form of micrometer screw gauge as shown in 
the figure, the trunnions were supported by the V-bearings in the arm, 

• Professor Judd pointed out that the clay with flints through which the rod 
passed pix)bablv contained small quantities of calcium carbonate which would be 
slowly dissolved by rain, and that this would produce a small error. —May 2, 1901. 
11. 1). 



of a Stoiie laid on the Stir/ace of the Grotmd, 



loo 



and the micrometer screw was iised for the measurement. 6 and H 
are the tops of the iron and copper rods; the micrometer screw is 
turned till its lower end K just touches one of the rods ; the upper end 
of the screw is not used at all. The stand and micrometer were kept 
indoors till wanted. 

Fig. 1. 




The method of reading was as follows : — 

The grooves for the feet of the stand were cleaned, and the stand 
placed with its feet resting in them. The trunnions of the micrometer 
gauge were placed in the V-bearings ; the screw was then adjusted till 
the lower end just touched the top of one rod ; by swinging the gauge, 
which hangs by its trunnions in the bearings, this adjustment could be 
done with great delicacy. 

The gauge was moved sideways by sliding the trimnions along the 
bearings ; this horizontal movement brought the screw over the centre 
of the second rod, and a second measurement was taken. This second 
measiu-ement, however, was not used. 

The tops of both rods were smooth, and a piece of copper was attached 
to the iron rod in order to give a surface which would not corrode. 
The micrometer screw was graduated to 0*01 mm., but as we had not 
realised the importance of making sure that there was not a small 
lateral displacement of the trunnions along the bearings, the la&t. ^W.^ 



256 



Mr. H. Darwin, (hi tlie Small Vertical Movements 



of the decimals was not reliable. This error existed because the 
horizontal movement of the trunnions along its bearings was not 
strictly parallel to the surface of the top of the rods from which the 
measurement was taken. As the readings from one rod only were used, 
it would have been better if this lateral displacement had been impos- 
sible. With care, however, consecutive measurements agreed within 
0*01 mm., showing that the method was capable of far greater accuracy 
than was required. 

Diuing the experiment the stone sank more than the range of the 
micrometer screw. The arm was unsoldered, moved upwards suffi- 
ciently far to allow the screw to be used again, and was then re- 
soldered. This operation, no doubt, introduced a small error. 

The curve markofl " Movement of Stone " in fig. 2 represents the up 

Fio. 2. 




and down movements of the stone from Februjuy 19 to October 9, 
1880, due to the varying dampness of the ground. 

The points corresponding to each observation are surroiuided by a 
small circle ; their vertical distance apart is the movement of the stone 
magnified 8 times, each division of the scale representing 1 mm. ; the 
horizontal distance apart is proportional time. 

The following are the observations from which the curve is con- 
stnicted. The numbers in the second column give the distance 
moved downward by the stone from its position on February 19, 
1880:— 



of a Stone laid on the Surface of the Chvund. 



257 





mm. 




mm. 


Feb. 19 .... 


.... 0-00 


Msy 18 .... 


.... 8-28 


„ 24 .... 


.... 0-28 


., 23 .... 


.... 8-62 


,. 29 .... 


.. . 0-43 


June 13 


.... 4-59 


Mar. 7 .... 


. . . . 0-54 


„ 22 .... 


.... 8-58 


,. 14 .... 


.... 0-97 


„ 29 .... 


.... 8-81 


„ 22 .... 


.... 1 '43 


July 12 .... 


.... 8-72 


., 28 .... 


. . . . 1-69 


Aug. 22 .... 


.... 4-66 


Apr. 6 


.... 0-89 


Sept. 7 .... 


.... 5-62 


„ 18 .... 


.... 1-11 


„ 14 .... 


.... 4-81 


„ 25 .... 


.... 1-43 


,. 19 .... 


.... 8-69 


May 2 .... 


.... 1-89 


„ 26 .... 


.... 8-91 


„ 9 .... 


.... 1-27 


Oct. 9 .... 


.... 8-58 



The curve shown by the dotted line roughly represents the dampness 
of the soil. Mr. Baldwin Latham has most kindly supplied me with 
the rainfall during this period at Leaves Green, about 1 mile distant, 
and nearly at the same level as Down. I have assumed that the soil 
dries at a uniform rate ; this assumption cannot be correct, but no 
other is possible. The varying rate of drying will, no doubt, depend 
on temperature, wind, and dryness of the air, as well as on the rate at 
which the water drains away. 

The ordinates are proportional to the amoimt of the rainfall, less the 
assumed amoimt which has evaporated or drained away ; both quantities 
are calculated from February 19, the date of the beginning of the 
curve. The curves representing the dampness of the soil and the 
movement of the stone are 16 mm. apart on February 19, the beginning 
of the experiment, and the rate of drying has been assumed to be 
great enough to bring them again 16 mm. apart on October 9, at the 
end of the experiment. 

The curves follow each other in a striking manner after May 18. 
On May 9 the stone-curve rises to a sharp peak when there was no 
corresponding rainfall, suggesting an error in reading the micrometer 
on that date ; this is the most probable explanation. Mr. W. N. Shaw 
tells me that there was a thunderstorm on May 4 in the South and 
West of England with variation in the local rainfall ; but this is unlikely 
to be the explanation, as the rainfall between May 1 and May 9 at 
Greenwich, 10^ miles distant, is the same as the Leaves Green, 1 mile 
distant. On April 6 there is again a discrepancy ; the form of the 
curve does not on this date suggest an error in the micrometer reading, 
and no explanation is suggested. 

The direct effect of artifically wetting the ground was tried on 
July 9, 1878. The ground was not dry, as there had been rain in 
the previous night. About one hour after the water had been poured 
on the ground near the stone it had risen 0*4 mm. ; six hours later it 
had risen O'l mm. more. 

Fig. 3 shows the permanent downward movement of the stone 1^^\&. 



258 



Mr. H. Darwin. Or the Small Vertical Manemenis 



anH l«>««P«I 



6 




1878 to 1896. The curve is constructed from readings taken near the 
middle of January when the ground was free from frost. The points 
which correspond to these readings are surrounded by small circles and 
are joined by straight lines. The points are at equal distances apart 



of a Stone laid oil the Surfoice of the Oround, 



259 



in a horizontal direction, and their vertical distance apart is 4/5 of the 
actual displacement of the stone, the numbers on the scale representing 
mms. This curve is marked " Winter." There were no winter readings 
after 1886. The Summer curve is made in a similar manner ; the dates 
of the observations are more irregular: the corresponding points, 
however, are equally spaced in a horizontal direction. 

The measurements from which the curve is constructed are as 
follows ; the second column gives the position of the stone measured 
in mm. : — 



mm. 




mm. 




mm. 


1878, Jan. 26 .... 30-91. 


..July 7 .. 


.. 24-60 


1887, Aug. 21 .... 


6-50 


1879, „ 3 .... 20-92. 


. „ 10.. 


.. 26-34 


1888, Sept. 20 .... 


10-34 


1880, „ 11 .... 26-59. 


. „ 12 .. 


., 22-24 


1889, „ 17 .... 


7-63 


1881, „ 9 .... 22-28. 


.. „ 29 ,. 


.. 16-84 


1890, „ 24 .... 


8 16 


1882, „ 9 .... 20-42. 


. „ 10.. 


.. 17-61 


1891, Aug. 6 .... 


8-90 


1883. Apr. 3 .... 17 82. 


.Aug. 1 .. 


.. 15-27 


1892, Sept. 6 .... 


7-72 


1884, no winter reading. . 


. Sept. 14 . . 


.. 11-38 


1893, Aug. 2 .... 


4*08 


1885, „ 


.July 19 .. 


.. 11-02 


1894, Aug. 24 ... . 


6-86 


1886, Mar. 1 .... 18-13. 


. No summer reading. 


1895, Sept. 17 .... 


2-50 








1896, Aug. 2 .... 


3-14 



The stone was accidentally removed and no readings were taken 
after 1896. 

If we take the winter readings, we find that the stone sank 
17*8 mm. in the eight years from January 1878 to March 1886, or at 
the average rate of 2*22 mm. per year, rather less than 1 inch in 
ten years. My father found* that small objects left on the surface of 
a field were buried 2*2 inches in ten years. This result is obtained 
from observations in a field near the stone. The large stone sank 
more slowly, a result we should expect. 

The curve shows that the rate of sinking was greater at the 
beginning than at the end ; this is probably due to the decaying of 
the grass ; the turf was not removed, the stone resting directly on it. 

The third curve, marked " Kain " on this diagram, roughly indicates 
the dampness of the ground. The ordinates of the curve are propor- 
tional to the rainfall at Greenwich Observatory during the twenty days 
before the date of the summer reading. The curve is only a ver/ 
rough indication of the dampness of the soil, as no account is taken of 
the rainfall for a longer period than twenty days before the observation, 
and neither is the evaporation during this period allowed for. The 
rainfall at Down also is assumed to be the same as at Greenwich, 
although they are 10^ miles apart, and Down is 569 ft. above Ordnance 
datum, and Greenwich is 155. 

The summer curve is far more irregular than the winter curve ; this 

• * Vegetable Mould,' 1888, p. 142. 



260 SmaU Verikal MnmnmUs of a Skm$ m tie Gfraund. 

no doubt is due to the greater variation in the dampneis of the soil in 
summer than in winter. The rain-cunre and stone-carve roughly 
follow each other. In 1888, however, the stone rises and the ndn- 
curve shows very little rain for the twenty days before September 20, 
the date of this observation. During June, July, and August a great 
amount of rain fell; and although there was very little rain from. 
September 1 to 20, the ground was probably damper than the rain- 
curve indicates. At Hayes, 3^ miles from Down, the rainfall on these 
dajrs was greater than at Greenwich, but still very small. 

If the points marked A and B are joined by a straight line, it will 
roughly represent the mean movement during the first nine years of 
the experiment. These points were selected so that the line joining 
them appeared to represent the mean movement to the best of my 
judgment. In the same manner the points C and D were selected, so 
that the line joining them represented the mean movement of the last 
nine years of the experiment. The movements deduced by this 
method are 2*3 mm. per year for the first nine years, and 0*36 mm. 
the last nine years. The slow movements for the latter period are 
surprising. The movement given above and obtained from the winter 
curve is 2*22 mm. per year. 

Fio. 4. 




During the last five years the rainfall on the twenty days before 
each observation was distinctly above the average; it was 2-09 inches, 
and the average for these twenty days during the whole experiment is 



Meeting foi' Discussion, May 9, 1901. 261 

1-54 inches. This -will perhaps partially explain the slow movement at 
the end of the experiment. 

The curve, Fig. 4, shows the movement due to frost. It is con- 
structed as before, and the ordinates represent the position of the stone 
magnified 8 times. On February 2, at 12.45 p.m., the thaw was 
beginning, but the ground was still hard ; readings were also taken 
at 3.25 P.M. and 5.25 P.M. The stone fell 2*37 mm. in 4 hours 40 
minutes. 



May 9, 1901. 

Meeting for Discussion. 

Sir WILLIAM HUGGINS, KC.B., D.C.L., President, in the Chair. 

A List of the Presents received was laid on the table, and thanks 
ordered for them. 

Professor Franz von Leydig was balloted for and elected a Foreign 
Member of the Society. 

The President stated from the Chair that the meeting was convened 
in pursuance of the following resolution of the Council, passed at their 
meeting on February 21, viz. : — " That a special meeting of the Fellows 
be called in order that the President and Council may have an oppor- 
tunity of hearing the views of the Fellows on the questions raised in 
the Eeport of the British Academy Committee, it being understood 
that no vote will be taken." 

The Report under reference was laid before the meeting, and a 
discussion ensued, in which the following Fellows took part: — Sir 
Norman Lockyer, Dr. Johnstone Stoney, Professor A. R Forsyth, 
Professor S. P. Thompson, Professor E. Bay Lankester, Sir John 
Evans, Professor A. Schuster, the Right Hon. J. Bryce, Professor J. D. 
Everett, Sir Henry Howorth, Sir A. Geikie, Dr. J. H. Gladstone, and 
Mr. G. J. Burch. 



262 Dr. S. BidweH On Negaiive Jfter-images, and 

May 23, 1901. 

Sir WILLIAM HUGGINS, K-CB., D.CX., President, in the Chair. 

A List of the Presents received was laid on the table, and thanks 
ordered for them. 

Professor James Grordon MacGregor was admitted into the Society. 

The following Papers were read : — 

I. " On the Presence of a Glycolytic Enzyme in Muscle." By Sir 
Lauder Bruxton, F.R.S., and Herbert Rhodes. 

II. " On Negative After-images and their Relation to certain other 
Visual Phenomena." By S. Bidwell, F.R.S. 

IIL "The Solar Acti^-ity 1833-1900." By Dr. W. J. S. Lockyer. 
Communicated by Sir Xorman Lockyer, K.C.B., F.R.S. 

IV. " A Comparative Crystallographical Study of the Double Selenates 
of the Series li2M(Se04)2,6H20.— Salts in which M is Magne- 
sium." By A. E. TuTTOX, F.R.S. 

V. "On the Intimate Structiu*e of Crystals. Part V. — Cubic Crystals 
with Octahedral Cleavage." By Professor W. J. Sou^s, F.R.S. 

VI. "Preliminary Statement on the Prothalli of Ophioglossum jmh- 
didumy L., Helminthostachys zeylanica, Hook., and PsUotum s^a" 
By Dr. W. H. Lang. Commimicated by Professor Bower, 
. F.R.S. 

The Society adjourned over the Whitsuntide Recess to Thursday, 
June 6. 



" On Negative After-images, and their Relation to certain other 
Visual Phenomena." By Shelford Bidwell, M.A., Sc.D., 
F.R.S. Received May 1,— Read May 23, 1901. 

I. Preliminary, 

In a former communication I described a curious phenomenon due 
to the formation of negative after-images following brief retinal 
excitation after a period of darkness.^ The elfect is conveniently 
demonstrated by the aid of a disc, partly black and partly white, 

• * Roy. Soc Proc.,' 1897, toI. 61, p. 268. 



tlieir Relation to certain other Visual Phenomena. 



263 



having an open sector, as shown in fig. 1. If such a disc is caused 
to turn five or six times in a second, while its surface is strongly 
illuminated, a coloured object placed behind it and viewed inter- 
mittently through the open sector, generally appears to assume an 
entirely diflerent hue, which is approximately complementary to the 
true colour of the object : a piece of red ribbon, for example, is seen 
as greenish-blue and a green one as pink. 



Fia. 1. 



Fio. 2. 





The tints thus produced are referred to in the paper as "pale" 
ones. I have since found that their intensity may in most cases be 
greatly increased if the object is illuminated more strongly than the 
disc. The best arrangement for the purpose is indicated in plan in 
fig. 2, where is the coloured object, €.(/., a design painted on a card, 
L, L are two incandescent electric lamps of fifty candle-power, and 
K is a third lamp of thirty-two candle-power, supported horizontally a 
little above the axis of the disc : all three lamps' are fitted with metal 
hoods to screen the light from the observer's ej'cs. The distance of 
the lamp K from the disc may be varied until the best results are 
obtained. WTien only a single lamp is used for illuminating both the 
object and the disc (as in the original arrangement), the light portion 
of the disc should be covered with paper of a pale neutral tint (not 
bluish), reflecting about half as much light as ordinary white paper ; 
for experiments in bright diff'used daylight, the paper may advan- 
tageously l)e of a pale yellowish-grey or buff tint. The dark part of 
the disc should be covered with good black velvet, and the open sector 
should extend to about 70% instead of only 45**, as recommended in 
the former paper. 

A number of olwervations made from time to time ynth. the appara- 
tus as thus modified have shown that the " pulsative " after-images, as 
they will be called, differ in several important respects from the 
" ordinary " negative after-images seen upon a white or grey back- 
ground after the gaze has been fixed for some seconds upon a coloured 
object. The colours of the pulsative after-images produced by certain 
hues of red and of green may appear far more intense or saturated 
than those of the ordinary negative after-images excit^l \>^ \Xi^ ^».\ssa 



264 Dr. a BidwelL On NegoHve Afterimages, mud 

primary colours under dmiUr conditions of illumination ; in particular, 
the greenish-blue into which bright red appears to be transformed is 
singularly strong and luminous. This is a matter for some surprise, 
since it might naturally be expected that the intermittent impressions 
of the exciting colour, even thou^ not consciously perceived, would 
be compounded with and tend to enfeeble the complementary hue of 
the after-image. On the other hand, when the exciting colour is blue 
or yellow, it is found difficult to obtain a satisfactory pulsative after- 
image. The complement of blue is an orange-yellow, which is also the 
hue of the ordinary after-image. But the pulsative image excited by 
blue, especially if Uie colour is at all bright, is in most oases im impure 
pink or salmon of feeble intensity. By using dull greyiah-blue pig- 
ments I have succeeded in obtaining a very &ir yellow, which is 
further improved if a little lamp-black is added to die paint. But in 
such cases the formation of yellow is no doubt chiefly attributable to 
the inferior luminosity of die pigment, for a perfectly neutaral-grey 
wash of lamp-black will itself give a yellow image, an effect which is 
probably due merely to intermittent illumination of feeble intensity. 
When a yellow pigment is the exciting colour, the hue of the 
pulsative image is not the complementary blue-violet but a pale 
purple, only just perceptibly bluer than the subjective piu*ple excited 
by green. A pulsative image which is really blue has never been 
obtained from any pigment whatever, the nearest approach being the 
greenish-blue excited by orange, or the bluish-purple which follows 
yellow. It has been found equally impossible to obtain either a true 
red or a true green in the pulsative image. All greens, ranging from 
yellow-green to green-blue, are transformed into some form of purple, 
including rose and pink. Purple produces in the pulsative image 
almost the same kind of blue-green as red, quite different from the 
pale grass-green colour characterising the ordinary after-image of a 
purple object 

The effects observed with the apparatus descril)ed above may l)e 
shortly summarised in the statement that the pulsative image of a 
colour in which red predominates is blue-green, that of dull blue is 
yellow, and that of any other colour (including bright blue) is purple 
or purplish-grey. In the experiments to be described in the present 
paper, spectrum colours were used instead of pigments, being blended 
into uniform mixtures by means of a simple form of Sir W. Abney's 
well known " colour-patch " apparatus.* 

II. Methods of Experiment, 

MetJiodL — The arrangement for generating pulsative after-images 
when the blended spectrum colours are projected upon a screen is shown 

• <Fhil. Trans./ 1886, Part II, p. 428. 




'^o/, 



^onto 



"""''"'''other n^^ 




266 Dr. S. Bidwell. On Negative After-images, and 

in fig. 3, on a scale of one-sixteenth. By means of the condenser B, the 
image of the positive crater of the electric arc A is projected upon the 
slit of the collimator D. The emergent parallel rajrs are refracted by 
the prism E, and thence pass successively through a circular aperture in 
the diaphragm F, through the achromatic lens 6, and through an 
opening in the rotating disc H (which renders the light intermittent) 
imtil they reach the slit-screen I, upon the face of which the spectrum 
is focussed by the lens G. The screen contains three adjustable 
vertical slits, the position of which can be varied ; one, two, or three 
selected portions of the spectrum may be allowed to pass through the 
slits to the large lens K, which is arranged to project a sharp image of 
the circular aperture in the diaphragm F upon the white screen L. 
This image constitutes the " colour-patch " ; it is illuminated by a 
uniform mixtiu'e of the spectrum-rays transmitted by the slit-screen. 

In front of the collimator-slit D is placed a mirror C, from the back 
of which a strip of the silver, 20 mm. long and 4 mm. wide, has been 
removed. So much of the imabsorbed light from the electric arc as 
does not pass through the clear glass to the collimator-slit is reflected, as 
shown by the dotted line, through the lens M to the mirror N ; thence 
it is again reflected through an aperture in the diaphragm O (whore 
an image of the condenser B is formed by the lens M) ; it then passes 
(intermittently) through an opening near the circumference of the 
rotating disc H to the wooden screen P, upon which an elliptical 
image, about 12 cm. by 4*5 cm., of the positive crater is formed. The 
image is crossed by a dark vertical band, corresponding to the space 
of clear glass in the mirror C. An opening in the screen P is 
furnished with an iris-iliaphragm, the aperture of which can be varied 
from 2 mm. to 30 mm. The mirror N is so placed that a portion of 
the image of the crater on one side or the other of the dark band may 
cover the iris-diaphragm. A lens Q focusses an image of the aperture 
in the iris-diaphragm upon the screen L, the disc of white light thus 
formed being concentric with the colour-patch. 

The following are details of the appiiratus : The collimator-slit is 
adjustable by a screw having a divided head ; the achromatic lens at 
the other end has a clear aperture of 2*86 cm. (1 J inch) and a focal 
length of 25*4 cm. (10 inches). The extra dense flint-glass prism E 
has a refracting angle of 60', and its faces are 51 cm. (2 inches) 
square. The diameter of the circular aperture in the diaphragm F is 
2-3 cm. {^\^ inch). The focal length of the achromatic lens G is 
76 cm. (30 inches), and its diameter 51 cm. (2 inches). 

The zinc disc, 11, as seen from the lantern, is represented in fig. 4. 
Its diameter is 34 cm. ; the opening near the centre extends to 45* 
and that near the circumference to 135'; both could be varied by 
movable zinc sectors, but the angles specified were found to l>e gener- 
aJIv the most effective. The disc is driven by an electric motor in 



tJieir Relation to certain other Visual Phenomena. 



267 



circuit with a variable resistance, the latter being adjusted so that the 
speed of rotation may be a little higher than is required for the ex- 
periment; a short-circuit key within reach of the observer's hand 
enables him to vary the speed at will or to keep it sensibly constant. 
A wire attached at right angles to the axis of the disc taps a strip of 
card at every revolution, producing a succession of audible clicks, which 
can, when desired, be compared with the taps of a metronome beating 
seconds. The most usual speed is from five to six turns per second 
The disc apparatus is supported at such a height from the table that 
when the disc is turning in the direction of the arrow the spectrum 
projected upon the screen I {^g, 3) is eclipsed at the moment when 
the iris-diaphragm in the screen P is beginning to be exposed to the 
white light. During about one-half of a revolution both the diaphragm 
and the slits are shielded by the disc. The width of the spectrum 
projected upon the slit-screen I (fig. 3) \& 2*9 cm., and its visible 
length in a dimly lighted room about 7 cm. ; the measured distance 
between A. 6870 (Fraunhofer line B) and A. 4115 (iron line between 
d and H) was approximately 6*1 cm. 



Pia.4. 




Fia. 6. 



M 



D 




•r 



The slit-screen is shown diagrammatically in fig. 5. It consists of 
a mahogany board, having cut in it an oblong window, 10*4 cm. by 
2-7 cm., over which the three brass slit-frames slide between grooved 
guides above and below. Each slit-frame is 1*8 cm, wide, and has an 
aperture of 2*5 cm. by 0*6 cm. The slit-jaws (not shown in the diagram) 
are attached to the front surfaces of the brass frames, and are adjustable 
in the parallel-ruler fashion, one of every pair being fixed to its frame ; 
the slits can be opened to 0*55 cm. The two outermost slit-frames are 
attached by screws to sliding shutters, which serve to cover such por- 
tions of the window right and left of the slit-frames as would other- 
wise be open to the light. The spaces between the middle slit-frame 
and the two outer ones are closed by opaque black ribbons (shaded in 
the diagram), constituting miniature spring-roller blinds. The axes of 
the spring rollers are so placed (perpendicularly beV\\TvA oxvft ^^<^ ^\ ^ 



VOL. LXVIII. 



AX 



268 .Dr. S. BidwelL On Ifegalive JfUr-image^, and 

slitrframe) that even when the slit-frames are in contact witib one 
another, and the slits are opened to their widest extent^ no obstruction 
to the passage of the light through the slits is presented by the rollers. 
Each slit-frame can be moved independently to any desired position, 
and clamped with a set-screw. On the other side (rf the sUt-screen a 
second pair of guides is fixed, each having three parallel saw-cut 
grooves in it. These guides carry rectangular pieces of sheet sine of 
various widths, which may be used to shield temporarily one or more 
of the slits when it is desirable that its adjustment shall not be dis- 
turbed. In some experiments it is necessary to use larger portions of 
the spectrum than can be transmitted by Uie slits ; the slit-frames are 
then removed from the screen, and the spectrum dealt with solely by 
means of the zinc plates. Pieces of zinc sliding in different pairs of 
grooves may be made to overlap one another, thus providing screens 
or openings of almost any desired width with very little trouble. 

The diameter of the lens generally used at K, fig. 3, is 10*2 cm. 
(4 inches), and its focal length 30*5 cm. (12 inches), the diameter of 
the circular colour-patch projected upon the screen being then only 
about 1*5 cm. This size was, however, amply suflBcient for most pur- 
poses, and with a larger image the necessary luminosity could not 
always be obtained. Sometimes a lens having a focal length of 
40*6 cm. (16 inches) was used at K, the diameter of the patch then 
being 2 cm. 

The focal length of the lens M is 12*7 cm. (5 inches); it is sur- 
rounded by a broad diaphragm to screen off stray light. O is a device 
known to photographers as a "rotating diaphragm"; it has eight 
apertures ranging from 0*21 cm. to 1*42 cm. in diameter, any one of 
which can be placed in the path of the beam of light. Its object is to 
vary the liuninosity of the white-light disc projected upon the screen L. 
The lens Q has a diameter of 6*5 cm. and a focal length of 16*5 cm. 
(6i inches). 

fFaffe-lmgihs of the Colour-patch Light. — No attempt was made to 
standardise the spectrum projected upon the slit-screen, the wave- 
lengths of the light illuminating the colour-patch being determined, 
when necessary, by means of the spectroscope K, fig. 3. The opaque 
white screen L being removed, a screen of ground-glass is put in its 
place, and the slit of the spectroscope is brought near the bright image 
on the glass. The purpose served by the ground-glass is to diffuse the 
light, so that any element of the Ught transmitted by the slit-screen 
may be at once examined without the need of turning the spectro- 
scope in its direction. The spectroscope has a six-inch circle with a 
vernier reading to minutes ; the prism is of extra dense Jena glass, the 
refractive index for D being 1*693. To ascertain the constitution of a 
. colour^patch, the deviations corresponding to the two extremes of the 
~ne or more coloured bands seen in the spectroscope are determined. 



their RelcUion to certain other Visual Phenomena, 269 

and the related wave-lengths are derived from a large-scale curve. 
When it is desired to form a colour-patch consisting of a mixture of 
light of given limiting wave-lengths, the slits in the slit-screen are 
moved and adjusted until the limits of the bright bands seen in the 
spectroscope coincide with the vertical cross-wire when the telescope is 
set at the proper predetermined angles. 

Illumination and Luminosity. — It should be remarked that the colour 
of an object, self-liuninous or illuminated, is not completely specified 
by a mere statement of the wave-lengths of the light which it emits or 
reflects. This fact is of course well known, but it is doubtful whether 
suflicient importance is always attached to it ; it has many times been 
strikingly brought to my notice in the course of the experiments under 
consideration. A complete account of the colour-conditions should 
include a determination of the luminosity expressed in terms of some 
standard unit; unfortunately, however, this cannot easily be given. 
In order to furnish data for approximately estimating the luminosity 
of the projected colour-patch when illuminated by selected spectral 
rays, a rough photometric measurement was made of the illiunination 
of the white colour-patch produced by the whole recombined spectrum, 
a " focus " electric lamp of 25*5 standard candle-power being employed 
for the comparison. It was found that when the width of the colli- 
mator-slit was 0*5 mm. (the width usually employed), the illumination 
was equal to that due to 8800 standard candles at a distance of 1 metre, 
or, as it may be called, to 8800 " candle-metres." Taking the lumi- 
nosity-sensation due to this illumination as the unit or standard of 
reference, the relative luminosity of a patch lighted by rays taken from 
any parts of the spectrum can be deduced from Abney's luminosity- 
curve for the normal electric-light spectrum.* For example, a purple 
colour-patch was formed by combining the red between A. 6380 and 
X 6600 with the blue-violet between A. 4250 and A. 4370. The area 
enclosed by the curve and the ordinates meeting the horizontal axis at 
6380 and 6600 was found to be 0'0361 of the whole, and the corre- 
sponding area for the blue-violet 0*0027. The luminosity of the purple 
patch relatively to that of a piece of white cardboard illuminated by 
8800 candles at 1 metre was therefore 0-0361 + 0*0027 = 0*0388. The 
variation from time to time of the intensity of the source of light, 
though no doubt considerable, is for the present purpose unimportant. 

Approximate values for the illumination of the white disc due to 
light reflected by the mirror C, fig. 3, and passing through the 
apertures in the diaphragm O, are given in the following table. 



• ' PhU. Tran*.,* A, toI. 193 (ISW^i, i^. 2ft^. 



270 



Dr. S. BidwelL On Negaiive JfUr-imoj^, and 



Table L 

Aperture Diameter. 

No. mm. Candle-metree. 

1 U-2 5600 

2 11-4 3600 

3 8-6 2050 

4 5 4 800. 

5 4 440 

6 3 2 280 

7 2 4 160 

8 2 1 120 

Method 11. — It is shown in fig. 6 how the colour-patch may be 
viewed directly by means of a Huyghens' eyepiece. A diaphragm 
having an aperture of 1 cm. is fixed in front of the prism (F, fig. 3) 
and is seen in the eyepiece when properly placed as a sharply defined 
bright disc illuminated by the coloured rays passing the slit-screen I. 
The apparent diameter of the disc is about one-fourth of that of the 
field of view. Its coloration is sensibly imif orm, but the method cannot 
be used to combine widely separated portions of the spectrum, and only 
a single slit was generally opened. The white light, which in the pro- 
duction of the pulsative after-image alternates with the coloured light, 
passes through the iris-diaphragm P, and the lens Q to the silvered 
mirror S; thence it is reflected to the imsilvered mirror T of thiii 
plate glass, which directs some of the light upon the eyepiece Y. For 
most observations pieces of ground-glass were placed behind the iris- 
diaphragm P and before the collimator-slit in order to subdue the 
light. 

Method III, — The apparatus is arranged as in fig. 3, but for the 
white cardboard screen there is substituted a piece of ground-glass 
covered with opaque paper, in which is cut a circular opening 1 cm. in 
diameter, the colour-patch and the concentric white-light disc being 
projected upon the opening. At a distance of 9 or 10 cm. behind the 
glass is placed a Huyghens' eyepiece, its position being such that the 
field of view is just filled with the coloured light. By the aid of this 
device observations can be made much more satisfactorily than when 
the image upon the ground-glass is viewed merely by the unassisted 
eye. Sajrs from any part of the spectrum can be combined ; but the 
absence of a surrounding white ground with which to compare the 
colour of the pulsative after-image is often found to be inconvenient. 
For some of the experiments a screen of thick brown paper attached 
to the rocking arm of a metronome was arranged to eclipse the 
spectrum rays periodically, without obstructing the white light ; thus 
k the pulsative image and the white light were seen in the eyepiece 
^temstely, each for a period of a little more than one second, and it 



their Relation to certain oilier Visical Phenomerui, 



271 



became easier to judge of the colour of the image. The iris-diaphragm 
was covered with ground-glass. 

Mfihod IF, — This is not a colour-patch method, but an ordinary 
spectroscopic one, the unmixed spectrum as dispersed by the prism 
being viewed through a tubeless telescope. The eyepiece V (fig. 7) 



Fi&. 6. 



7 



FlQ. ?• 



.c=^ 



H-" 



^ 




\ ^1 T 



\ / 



fl' 



ff-* 






/ 



&' 



occupies the place of the slit-screen behind the disc H ; white light is 
reflected into the eyepiece by the silvered mirror S and the clear 
plate-glass T, as in Method II. A sheet of ground-glass takes the 
place of the iris-diaphragm, which is removed. The arrangement is 
in all essential respects similar to that adopted by Mr. Burch,* except 
that the reflected white light is derived from the electric arc instead 
of from the sky, its intensity being capable of wide variation. About 
one-third of the whole length of the spectrum can be seen at once ; the 
eyepiece is so directed that the spectnun may occupy only the lower 
half of the field, while the white light, when admitted, fills the whole 
of it. 

Ordinary •Negative Afiei'-images, — The apparatus, whether arranged 
for the projection of a colour-patch upon a screen or for observation 
with an eyepiece, is exceedingly well adapted for the study of ordinary 
negative after-images. The zinc disc H is set so that a coloured 
image is formed upon a black ground; after this has been gazed at 
for 10 or 20 seconds, it is obliterated by turning the disc through a 
• « Boy. Soc. Proc.,' vol 66, p. 215. 



272 Dr. S. BidwelL On Negative AjUr^vmageie^ and 

small angle, a white patch of any desired Inminosity appearing in its 
place. The hues of the negative images seen upon the white patch 
are often very different from those of the pulsative images formed 
when the disc is rotating continuously. 

III. PuUsaike Images due to Various Colours. 

Bed. — A red colour-patch formed on the screen by a combination of 
rays extending from the extreme limit of the spectrum to X 6450 gives 
no pulsative after-image at all, the white-light disc, whatever may be 
its intensity, appearing white throughout. If the slit is further opened 
to admit rays up to X 6320 a faint blue^een image is seen upon the 
white-light disc, provided that the latter ia not too strongly illumi- 
nated ; with apertiu^ greater than No. 5 of the diaphragm O, fig. 3, 
the blue-green image disappears. The absence of a pulsative image 
after a low red is, no doubt, in great measure due to the superior 
persistence of this hue, for the ordinary after-image is quite distinct. 

In general the pulsative images of red, or of red and orange mixed» 
are of a blue-green tint, exceeding in brightness and apparent satura- 
tion those due to any other exciting colours. Perhaps the strongest 
effect was observed when the colour-patch was illuminated by rays 
from about A 6100 to A. 6550, aperture No. 4 of the rotating 
diaphragm being used for the white-light disc. No pulsative image 
of the red can, however, be formed imless the luminosity of the patch 
is fairly great. 

With the eyepiece methods a feeble pulsative image was excited by 
red in the neighboiu^hood of the B line. Its hue appeared bluish with 
a slight tinge of green. In other respects the results for red were 
similar to those obtained by Method I. 

Orange. — A colour-patch was formed by mixing rays from A 5800 to 
X 6150. Its ordinary after-image was bright sky-blue. The pulsa- 
tive image upon the screen appeared a rather dull blue-green with 
aperture No. 2 of the rotating diaphragm and green-blue with 
apertures 3 and 4. The eyepiece method showed the colour as 
bhie-green, paler than that excited by red. 

Yellow. — The ordinary after-image of a patch of yellow, A. 5700 to 
A. 5890, was blue-violet. The tint of the pulsative image on the screen 
was a pale nearly neutral grey, pinkish when the illumination was 
weak, bluish when it was strong. A slightly more orange yellow, 
A. 5700 to A. 5980, gave an image of nearly the same character but 
a little stronger. When the eyepiece methods II and III were 
employed with yellow, the pulsative images were exceedingly feeble, 
and generally appeared to contain a trace of pink. The image due 
to a greenish-yellow, X 5590 to X 5740, was more decidedly pink or 
pale purple. Similar effects were obtained when the exciting yellow 



their Rdaiion to certain other VistuU Phenomena. 273 

was produced by mixing red and green rays. An orange-yellow, 
made by combining the spectrum rays from the extreme red to 
X 5340 in the green, had a slate-coloured or nearly neutral pulsative 
image; the addition of a very little more green turned the image 
pink. 

Green, — A colour-patch sufficiently illmninated by green rays taken 
from any part of the spectrum between greenish-yellow and greenish- 
blue inclusive (about A. 5750 to A. 5050) produced a pink or dilute purple 
pulsative image; the purple was strongest when the exciting colour 
was a full green, but it never reached an intensity equal to that of 
the blue-green excited by red when the conditions were most favoui-- 
able. On the other hand, there can be no question that a piu*ple 
pulsative image after green is much more easily produced than a blue- 
green one after red, a fact which tends to indicate that, at least after 
H short period of repose, the colournsense organs become fatigued more 
quickly by green light than by red. It seems to be generally believed 
that the red sensation is more readily exhausted than the green.* 
llood,t however, attributes the "well-known intolerance of all full 
greens to the fact that green light exhausts the nervous power of the 
eye sooner than light of any other colour," this exhaustion being 
"proved by the observation that the after-pictures ... are more 
vivid with green than with the other colours." The results of my 
own observations lead me to think that while after a prolonged gaze 
nt brightly illuminated colours, blue-green after red is more con- 
spicuous than purple after green, the opposite may be the case when 
the exposure has been brief or the illumination feeble. In the case of 
the pulsative image, however, account must be taken not only of 
fatigue, but also of persistence and of the latent period during which 
the first impact of light upon the eye fails to produce any recognisable 
sensation. 

Blue, — Though the ordinary after-image of blue is orange, the 
pulsative image upon the screen was generally seen as some form of 
impure purple^ variously described as dull pink, salmon, or flesh colour. 
The same was often the case when the eyepiece methods were employed. 
Among the blues tested were a mixture of A 4700 to A. 4950, and one 
of A. 4550 to X 4760, besides many others of which the limiting wave- 
lengths were not determined. By Method II a good orange-yellow 
image could always be produced from' the last-named blue, provided 
that the illumination was sufficiently strong and the various lumi- 
nosities carefully adjusted. 

Blue-violet and Violet, — The ordinary after-image is yellow. The 
screen method showed scarcely any image at all for light of wave- 
lengths less than about A. 4500. With the eyepiece methods the image 

• Foster, < Tezt.book of Phjsiologj,' 6th edition, p. 1382. 
t ' Modern Ohromatics,' 2nd edition, p. 295. 



274 Dr. a BidweH. fOm Wtgaiive After-imugu, and 

tiBuaily appeared as a pale bluiBh-pink, which could be closely matched 
by blue-violet diluted with much white. The persistence of violet 
impressions is very great, and it is not unlikely that the bluish-pink 
image was due merely to the intermingled action of the violet and 
white-light rays (as in a Maxwell's disc), and was not a true pulsative 
after-image. In the circumstances mentioned in the last paragraph, 
when blue light gave an orange pulsative image, blue-violet also gave 
a yellow one, the persistence of blue-violet being less with strong than 
with weak illumination. 

Purple. — A bright purple was made by combining red, X 6180 to 
X 6810, with blue-violet, X 4330 to X 4420. The ordinary after-image 
of the red alone was blue-green, and that of the purple grass-green. 
The pulsative image of the purple formed on the screen was, however, 
blue-green, and when the slit admitting the blue-violet light was 
alternately covered and uncovered, no change in the colour of the 
image could be detected. 

IV. Pulsative After-image of JVhite. 

Recombined Spectrum. — If the slit-frames and their appurtenances are 
removed from the slit-screen I, fig. 3, the whole spectrum is recom- 
bined by the lens K, and forms upon the screen L a white '^ colour- 
patch," the illumination of which can be varied in a known manner by 
changing the width of the coUimator-slit. The illumination of the 
" white-light disc " (which, during an experiment, alternates with the 
white " colour-patch ") can also be adjusted to certain known intensi- 
ties. A large number of experiments, which need not be described in 
detail, were made with various illuminations of the white colour-patch 
and of the white-light disc. The colour of the pulsative images of 
the white patch, which is not in general neutral like that of the ordi- 
nary after-image, was found to depend not only upon the absolute 
values of the two illuminations but also upon their ratios. Broadly 
speaking, it may be stated that with feeble illumination the patch 
appeared yellow (probably only an effect of weak intermittent light), 
with very strong illumination it was a neutral grey, and with all such 
intensities of illumination as are ordinarily employed it appeared a 
more or less decided purple. 

In my former paper reference was made to the purple tint assumed 
by a white cai*d when seen through the original black and white disc, 
and a distinguished physiologist, who saw the effect, expressed the 
opinion that the colour might be due to the ''visual purple." In the 
light of the observations described in the present paper, it seemed 
possible that the phenomenon might be explained by the hjrpothesis 
that the purple was really an after-image of the green component 
hieb, according to the Young-Helmholtz theory, is contained in the 



their RekUion to certain other Vimal Phenome^ui. 275 

white light. All the various components set up fatigue after a 
moment's action, but green more than the others ; if, therefore, the 
green stimulus were diminished to an extent corresponding to the 
excess of fatigue which it produced, the tint of the pulsative image 
might be expected to become neutral, like that of the ordinary nega- 
tive after-image. Different parts of the green portion of the spectrum 
were accordingly cut out by interposing strips of black card of various 
widths, and it was found that when the green rays from X 5030 to 
A. 5470 were intercepted, the tint of the pulsative image was absolutely 
neutral. 

JFhite compounded from Bed and Blue-gieen. — Such a white always gave 
a pink pulsative image — a fact which confirms the inference derived 
from previously described observations that the blue-green sensation 
is, after an interval of repose, more readily fatigued than the red 
sensation. 

White compounded fiom Yellow and Blue, — A white colour-patch was 
formed by combining a blue of A. 4530 to A. 4710 with a yellow of A. 5650 
to A 5860. The colour of the pulsative image was rather doubtful, but 
an artist (who did not know what to expect) unhesitatingly pro- 
nounced it to be yellow. Since the Young-Helmholtz theory supposes 
that yellow excites the green sensation, this restilt was imexpected. It 
is also opposed to the usually received opinion that the sensation of 
yellow is more readily exhausted than that of blue.*^ 

V. Pulsative Images of Complete Spectrum, 

The spectrum was projected upon a screen covered with white card- 
board, which was put in the place of the slit-screen, as shown in fig. 8. 




The beam of intermittent white light was reflected upon the screen by 
means of a mirror and formed an oblong bright patch upon the site of 
the spectnun. The upper part of the mirror was covered by a screen, 
so arranged that the site of the spectnun was longitudinally divided 
into two equal parts, the lower of which was exposed to intermittent 

• Foiter, loe. eit. 



276 Dr. S. BidwelL On Niegaiive After-imagu, and 

white light, while the upper was not Thus the spectrum and its 
pulsative image could be seen together, the one above die oth^. At 
first sight the pulsative image appeared to contain only two colours — 
blue-green corresponding to the spectral red and orange, and purple- 
pink corresponding to the green. Closer inspection revealed a pale 
grey band between the blue-green and the purple, and a feeUe tint of 
lavender corresponding to the blue of the spectrum. Nothing at all 
could be seen beneath the violet and the extreme red. The boundaries 
of the several colours of the pulsative image were found to be roughly 
as follows :— Blue green, X 6800 to X6000; grey, X6000 to X5800; 
purple, X5800 to X5000; lavender, X5000 to X4300. 

Observations were also made of the changes undergone by the red 
and green of the projected spectnun when the illumination was varied 
by altering the width of the collimator^lit. With a width of 0*06 mm. 
neither of the spectrum colours was at all affected; they appeared 
simply as intermittent red and green. With 0*125 mm. the green had 
become transformed into' a purple, intermixed with which a little green 
could sometimes be glimpsed ; this latter completely disappeared when 
the slit was made 0*2 mm. wide, the apparent colour being with this 
and all greater widths of slit a steady purple. At the same stage 
(0*2 mm.) red was still seen as red, though a flicker of blue-green could 
be detected upon it. At 0*45 mm. red appeared as blue-green with a 
red flicker, which ceased to be perceptible, except along the extreme 
edge, when the width of the slit was increased to 0*5 mm. With a 
slit of 0*94 mm. wide the last trace of red had vanished. Thus the 
more ready exhaustion of the green sensation is again evidenced. 

VI. Colour Changes with Reversed Cycle, 

If the cycle is reversed by making the zinc disc turn in the opposite 
direction, most of the spectrum colours undergo remarkable changes. 
Red becomes rose-purple ; orange a diluted crimson ; yellow is made 
much paler, as if veiled by a white haze ; green appears as blue-green, 
and blue-green as blue. Blue and violet are very slightly affected. 
Very similar effects are observed when the disc described in Section I 
is turned in the reverse direction. They naturally suggest that white 
light excites a blue or blue-violet sensation, the persistence of which 
exceeds that of any other fundamental sensation. 

VII. External and Border Phenomena. 

Some very remarkable and interesting phenomena are exhibited in 
the region of the visual field immediately adjacent to that upon which 
a *' pulsative after-image " is being produced. It is a matter for sur- 
nme that one should be able to perceive after-images without detecting 



their Relation to certain other Visual Phenomerui. 277 

any indication whatever of the colours to which they are due, but it is 
perhaps even more siu:prising to find that parts of the retina upon 
which the intermittent white light does not fall may also be absolutely 
blind to the exciting colour. 

The effect in question is conveniently demonstrated by the arrange- 
ment illustrated in fig. 9. A piece of clear glass, upon which is 

Fig. 9. 




gummed a small circle of black paper or tinfoil, is fixed behind the 
iris-diaphragm P, fig. 3, and thus a round black spot, 0*6 cm. in 
diameter, is formed at the centre of the white-light disc projected 
upon the screen L. In fig. 9 the outer circle represents the white- 
light disc, the shaded circle the colour-patch, and the inner one the 
black spot upon the white-light disc. Suppose the colour-patch to bo 
green. When the apparatus is worked, the shaded circle becomes 
purple ; the site of the black spot, being illuminated five or six times 
in a second by green light, might be expected to appear green ; but if 
viewed from a distance of 30 cm. or more it remains perfectly black 
throughout ; under normal conditions no trace of a flicker of green 
light can be seen upon it. The apparent width of the blind region 
adjoining the site of the pulsative image, therefore, exceeds half a 
degree. 

This induced blindness is most conspicuous when the light is green, 
and hardly less so when it is yellow ; it does not occur at all with 
extreme red nor with violet light, which illuminate the site of the black 
spot quite strongly ; but its absence is certainly not entirely due to 
the inferior luminosity of those hues. With a very narrow slit green 
can indeed be seen in the central part of the spot by an observer 
stationed quite near the screen ; but if he is at a distance of 1*5 metre, 
the green light may be weakened by gradually closing the slit until 
the pulsative image completely disappears, yet no green is ever seen 
upon the spot. 

The following are the results noted in one experiment, when a slit 
was moved across the spectrum from end to end. fied was seen upon 
the spot, at first nearly continuously, then intermittently, imtil the slit 
reached about X 6220, when, unless the illuminatioTi ^«a tcl^^ ^^t^ 



278 Dr. S. BidwelL On Negative Jfier^mage$, and 

feeble, the spot became uniformly black, remaining so untQ about 
X 5000, at which point a blue flicker began to appear ; at X 4700 the 
spot had become steadily blue. Blue-violet and violet seemed to 
illuminate the spot much more steadily than red. It was noticed that 
as soon as the black spot became distinctly coloured the pulsative 
image almost disappeared; the weakness of the pulsative images 
excited by light corresponding to the two ends of the spectrum may 
therefore probably be accounted for by supposing that the negative 
after-images become blended eith^ widi the primary images, or with 
positive after-images, or perhaps with both, producing the effect of 
white. 

It was found possible to observe these phenomena not only when the 
zinc disc was spinning continuously, but even with a single properly 
timed cycle of (1) darkness ; (2) colour-patch ; (3) white light ; (4) dark- 
ness. When the spectrum light was green, there appeared for a moment 
a bright white disc with a perfectly black central spot, which was 
surrounded by a well-defined purple annulus (as in fig. 9), the whole 
being free from any \48ible trace of green. 

When a purple pulsative image excited by green rays was viewed in 
the eyepiece by Method II, it was seen to be surrounded by a purple 
corona, which extended considerably beyond the well-defined boundary 
of the aperture in the diaphragm (F, fig. 3). Sometimes, indeed, when 
the illumination was strong, the purple of the corona appeared to be 
fuller or more saturated than that of the image itself. Moreover, a 
purple haze of greater or less intensity always extended over the whole 
field of the eyepiece. These phenomena are, of course, to be explained 
by the " induced " blindness to green light which was demonstrated by 
the black spot. 

Certain border effects of an entirely different character were also 
observed. If the rays illiuninating the circular patch seen in the eye- 
piece were taken from the red, orange, or yellow regions of the 
spectrum, the image appeared to be surrounded by a narrow red, or 
rather crimson, border. Measurements of the composition of different 
colour-patches which showed this effect include a red of X 6420 to 
X 6600, a reddish-orange of X 6200 to X 6280, an orange-yellow of 
X 5890 to X 5990, and a yellow of X 5740 to X 5860 ; in the last case, 
the border was less conspicuous, but still recognisable with certainty. 
With a greenish-yellow patch containing rays from X 5650 to X 5750 
no trace of the crimson border could be detected. It turned out that 
these crimson borders could be seen when the intermittent white light 
was screened off, though they were less easily visible against the dark 
background than against the bright one. They evidently belong to a 
elass of phenomena discussed in a former paper,"*^ in which it was 

* * Boy. Boo. Proo.,' vol. 60, p. 868, " On Subjectiye Colour^phenomenA attending 
Sudden CbangcB of Illamination." 



their Belaticn to certain other Visual Phenomena. 279 

shown that when a bright image is suddenly formed upon the retina 
after a period of darkness, the image generally appears for a moment 
to be surrounded by a narrow red border. The paper referred to con- 
tains an account of an experiment* demonstrating that when the 
bright object producing the image was looked at through variously 
coloured glasses, the red border did not appear unless the glass used, 
when tested spectroscopically, transmitted red light, and it was 
suggested that the phenomenon was due to sympathetic excitation of 
the " red nei*ve fibres " l3dng immediately outside the portion of the 
retina exposed to the direct action of the light. The orange and 
yellow glasses employed in the experiment referred to of course 
transmitted red light ; it is interesting to find that the pure orange and 
yellow rays of the spectrum, of wave-length not necessarily exceeding 
about X 5800, are competent to give rise to the same red borders. 

These effects can be exhibited equally well by Methods I and II, the 
observations being rendered much easier by the aid of a device 
described in the former paper. A darning needle, blackened with 
camphor smoke, is cemented vertically across the opening in the 
diaphragm F, fig. 3, dividing the bright disc which is projected upon 
the screen or seen in the eyepiece into two equal parts. Each half 
disc then has its red border, and, if the intervening space is sufficiently 
narrow, the red borders along the two contiguous vertical edges meet, 
or possibly even overlap, with the result that the focussed image of the 
needle should appear to be red. This was the case when the slit wa» 
placed in any part of the spectrum between the extreme red and the 
greenish-yellow. With the slit in the greenish-yellow itself the image 
of the needle appeared to be almost colourless, but as the full green 
was approached the colour became a rather dark shade of blue-green,, 
and remained so until the slit reached about X 4500, near the beginning 
of the blue-violet, when the needle again became colourless. In a 
colour-patch formed of the pure blue rays from X 4600 to X 4725 the 
contrasted blue-gre^n hue assumed by the image of the needle was 
strikingly conspicuous. The border-colour in question cannot easily be 
observed unless the intensity of the illumination is within certain 
limits ; for, as in the case of the red borders which were discussed in a 
former paper, t the blue-green hue becomes transformed into its comple- 
mentary if the light is very strong, and the needle appears reddish. 
For the green part of the spectrum it is especially necessary that the 
illumination should be very carefully adjusted ; indeed, the phenomenon 
would probably never have been noticed at all with green light if its. 
remarkable appearance when the light was pure blue had not first 
attracted attention. For the more refrangible part of the spectrum it 
is desirable to place in front of the collimator-slit a piece of blue glass 

• Experiment IT, loc, eii,, p. 872. 

t • Boy. Soo. Proc./ 1897, toI. 61, p. 268. 



280 Dr. S. BidwelL On Negaiite After-imaget^ and 

which will obstruot the red rays ; possible sources of error due to the 
reflection of red light by the prism are thus avoided. The origin of 
these blue-green borders is, no doubt, analogous to that of the red 
borders, but the matter requires more careful and thorough inyeetiga- 
tion than it has yet received. 

Though the image of the needle was colourless when the patch was 
illuminated by the greenish-yellow rays. of the spectrum, it appeared 
red when the same hue was formed by c6mbining red and green rays. 
Bed borders were also observed with a purple composed of red and 
blue rays, with a white composed of red, green, and violet rays, and 
with another white formed by reoombining the whole of tiie spectrum ; 
this last observation was, of course, practically a mere repetition in a 
slightly different form of the one which formed the chief subject of my 
previous paper. 

No coloured border of the same class has yet been observed when 
the oolour^patch was illuminated by the violet rays of the spectrum, 
Method II being the one employed. The edge of the yellow pulsative 
image was fringed with a pale violet rim, which, however, was wholly 
inside the geometrical boundary of the image and not external to it, as 
were the red and the blue-green borders. Red was very carefully 
looked for around the violet, but not foimd. The so-called " simul- 
taneous contrast" effect was, however, very remarkable, the whole field 
of the eyepiece appearing of a strong yellow tint ; often it was quite 
as strong as the colour of the image itself, which could only be dis- 
tinguished from the background by the narrow violet ring surrounding 
it. An equally remarkable effect was produced when the stimulating 
light was blue, the " contrast-colour " being, like that of the image, 
orange. 

Vlll. Discussion of tlie ObservcUions. 

Nature of the Pulsative Image. — The phenomenon which, for brevity, 
has been termed the '^ pulsative after-image," may be defined as the 
negative after-image of a coloured object which is seen against a white 
ground after a very brief stimulatipn — 1/60 to 1/30 of a second — 
following a period of repose. A strange peculiarity incidental to the 
formation of these after-images is, that under suitable conditions of 
illumination, the true colour of the light to which the phenomenon is due 
altogether fails to evoke its appropriate sensation and in not perceived 
at all, the only colour seen being that of the after-image. The diffi- 
culty experienced in attempts to find a really definite explanation of 
this fact, and illustrate it by curves of sensation, is in some degree 
diminished by the singular observations upon the " black spot." The 
black spot is, of course, merely a device for exhibiting a certain 
border effect in a convenient manner. A small disc of green light is 



their Relation to certain other Visual Plceiuyintna. 281 

flashed upon a white screen for about a fortieth of a second, and is 
immediately replaced by a concentric annulus of white light. During 
this process no green is seen at all ; there appears only a purple annulus 
-surrounding an area which is perfectly black. The white light clearly 
has the effect of restraining the visual sense-organs adjacent to those 
upon which it falls from responding to the green stimulus. It would 
seem to follow a fortiori that the sense-organs directly acted upon by 
the white light must be similarly incapacitated from evoking any green 
sensation. It is not the fact that the green sensation is produced for a 
moment and then swamped by a more powerful white one so completdy 
as to escape notice ; it actually never comes into existence. Neverthe- 
less, the effects of fatigue by green are exhibited, and the physically 
white annulus is seen as purple. 

It may be well to state that when once the necessary apparatus has 
been set up and the various liuninosities adjusted to the order of those 
specified, the "black spot" observation is an exceedingly easy one. 
No skilled observer is required for it ; it can be made at once by any 
one whose vision is normal, and the phenomenon can at any time be 
exhibited with certainty. 

No explanation of it can, I think, be afforded by the Young- 
Helmholtz theory of colour-vision in its current form ; an independent 
white sensation must be postulated, as by the theory of Hering. 
And the observations point to the conclusion, even if they do not of 
themselves sufficiently prove it, that the latent period for a coloiu*- 
sensation is very much greater than that for white. For green, under 
the conditions of my experiment, the latent period must be at least 
1/40 second, while for white it can hardly exceed 1/500 second, 
though the luminosity of the two may be nearly equal. The latent 
period for red is probably not very different from that for green under 
similar circiunstances, that for blue being considerably greater ;* but it 
is not quite certain whether the red and blue flickers seen upon the 
black spot are produced before or after the illumination by white 
light. I am inclined to think that the latter is the case, the negative 
after-image being followed during the period of darkness by a positive 
one. In all cases the duration of the latent period probably depends 
partly, through certainly not wholly, upon the intensity of the 
illumination, t 

If in a darkened room a ray of green light is admitted to the eye 
for a period of 1/40 second, one sees a flash of green; but assuming 

* Some preliminary obeervaUons by a method of which I hope to submit an 
account at a future date indicated that, under the conditions of the experiments, 
the latent period was for red O'OSl sec., for green 0'028 sec, and for blue 0*040 sec. 

t According to Sxner, "If the intensities of the illuminatiop of an object 
incrcaao in geometrical progression, the times necessary for the perception of 
the same decrease in arithmetical progression/' ' Wien. Akad. Sitzber.,' toL ^^ 
AbtheUII,.p.624,1868. 



282 Dr. S. BidwelL On Negative Jfier^magee, and 

that the suppgeitions which hare been put forward are correct^ tlia 
visible flash is not contemporaneous with the phjrsical illuminatioii. 
One does not begin to experience the green sensation until after the 
green ray which excited it has been shut off. What is actually per- 
ceived is, in fact, a positive after-image, the duration of which may be 
considerably longer than that of the stimulus. But if a sufficiently 
luminous white surface is presented to the eye immediately upon the 
expiration of the brief period of stimulation by green light, the after- 
image formed will not be positive but negative, and the only colour 
perceived will be purple. The fatigue to which the negative image is 
due must have been set up during the latent period when no image at 
all was actually perceived. It is noteworthy that if the white back* 
ground is eclipsed by black before the expiration of the period during 
which the positive after-image normally continues, the purple n^ative 
after-image is seen to be followed by a green positive one, which appears 
as a bright object upon the dark ground. 

One other point requires notice. According to Hering's theory, rays 
of every wave-length excite not only the sensation of a colour but 
also that of white. Supposing therefore that the colour-sensation lags 
behind the white-sensation, we should expect that when the zinc disc 
is turned, the black spot, even if no colour showed upon it, would 
appear more or less grey. This, however, is not the fact, at least to 
any perceptible extent; on the contrary, the spot appears more 
intensely black when it is illiuninated by intermittent green light than 
it does when the green light is screened off. In the latter case (when 
no light whatever falls upon it) the spot seems to be veiled by a faint 
haze, the origin of which I have traced to a phenomenon attending 
sudden changes of illumination described in a former paper.* The 
" black spot " phenomena are therefore not fully in accord with either 
of the leading theories of colour-vision. 

Red and Green Baide^s. — The narrow red and blue-green borders 
which appear to surround colour-patch images formed from different 
parts of the spectrum obviously point to the excitation of funda- 
mental red and blue-green colour sensations, the effects of the 
excitation being sympathetically extended beyond the geometrical 
boundaries of the images projected upon the retina. Bed borders are 
exhibited by colour-patches formed from any mixture of spectral rays 
which contains a considerable proportion of red; they also appear 
around patches illuminated by the simple orange and yellow rays of 
the spectrum (though with the latter they are feeble) and around 
white patches. With mixtures of spectral rays from which red, 
orange, and yellow rays are excluded, they are never seen. A blue- 
green border, on the other hand, appears only when the green or the 
blue of the spectrum enters into the combination, the addition of blue- 
• See * Roy. Soc. Proc.,* toI. 60, p. 370, experiment I (2). 



tluir Relation to certain other Visxuil Phenomena. 283 

violet and violet having no sensible effect, while an admixture of red, 
orange, or yellow causes the border to become red. The intensity of 
the red borders is much greater than that of the blue-green, and if 
the two could occur together, the blue-green would no doubt be over- 
powered. According to Hering's theory the red and blue-green 
fimdamental sensations, being antagonistic, cannot both be excited at 
the same time, and it is to be remarked that those spectral rays which 
are less refrangible than the greenish-yellow produce red borders, 
while those of refrangibility intermediate between greenish-yellow and 
blue-violet produce blue-green borders, which is nearly what the 
Hering theory would require. According to the most recent exponents 
of the Young-Helmholtz theory, green spectral rays excite the funda- 
mental red sensation to about the same extent as orange-red rays ; 
yet no red border is formed by the green, though that formed by the 
orange-red is very strong. If the presence of these borders may be 
taken as affording evidence of the excitation of fundamental colour- 
sensations, the evidence so far is in favour of Hering's views. But on 
the other hand the fact that the red borders can be caused by all kinds 
of white light seems to show that white excites the fundamental red 
sensation, while there is some evidence in Sections IV and VI that it 
excites green and blue or violet colour-sensations as welL No indica- 
tion as to what one or more colour-sensations in addition to red and 
blue-green are fimdamental ones has yet been afforded by the class of 
border phenomena under discussion. 

Simultaneous Contrast. — When a purple pulsative image of a very 
bright green patch is formed upon a white ground by the eyepiece 
method, the whole physically white field appears to be strongly 
purple, a fact which shows conclusively that the phenomenon of 
simultaneous contrast may in certain cases be absolutely independent 
of mental judgment. It cannot be that the ground appears purple 
simply from contrast with green, for no green whatever is consciously 
perceived ; the cause must necessarily be a physiological one. Similar 
remarks apply to the orange and yellow fields which accompany the 
pulsative images of blue and violet patches. It is curious that with 
a red patch the coloui- of the field is but very slightly affected. 

But while these observations show that in certain cases the so- 
called contrast effects must, have a physiological origin, it is beyond 
question that this is not invariably so. Some of Helmholti's well-known 
experiments leave* no room for doubt that mental judgment is some- 
times the sole cause of contrast phenomlena. 

Colours of tJie Pulsative Image. — The chief results of the colour 
experiments are collected in Table II. One of the most noticeable 
features is the superior intensity of the pulsative after-images of red 
and green; another is the intrusiveness of some form of purple. 
Purple after green is, as before mentioned, more easily obtainaibl^ xWw 

YOU LXVIII. -X. 



284 



On Negative After-iviages, &e. 



any other colour, and if the appearance of purple in the pulsative image 
may be regarded as a test for the presence of green in the Ituninous 
object, then it appears from Nos. 4, 8, and 9 that green is a constituent 
of yellow, of blue, and of white. 



Table II. 



Bef. 
No. 



10 



11 



12 



Spectrum 
colours. 



Extreme red 



Complementary 
colours. 



Green-blue . . 



Bed I Blue-green. . . . 

Orange Blue 

Yellow j Blue-violet . . 

I 

Green- jellow Violet 

I 
Green I Purple 



Blue-green . . ' Bed 

Blue Orange-yellow 



Blue-violet 
and Tiolet 



Purple . 



White 



Spectrum . . 



Yellow 



Green 



Neutral grc;-. 



Pulsatire 
colours. 



Bemarks on pulsatire 
image. 



Green-blue . . . . 

Blue-green .... 
Pale blue-green 

Neatly neutral 



Pink, or pale 
purple 



Purple . 



Purple 

(1 ) Dull pink 
(2.) Orange 



(I.) Bluish-pink 
(2.) YeUow 

Blue-green .. 



(1.) Purple or 
purplish -grey 
(2.) Neutral 



The image oould only be 
seen by direct yirion. 
None was formed on the 
screen. 

The most intense of all 
pulsatire colours. 

Green-blue with strongest 
illumination and direct 
rision. 

Pinkish with ordinary il- 
lumination, bluish with 
strong. Always incon- 
spicuous. 

Mixed red and green light 
gave images similar to 
those of Nos. 4 and 5. 

Inferior only to No. 1 in 
intensity. Easier to pro- 
duce than any other. 

Nearly the same as No. 6. 

(1.) For ordinary illumi- 
nation and on screen. 
(2.) For intense illumi- 
nation with direct vision. 

Bemark as for No. 8. 
Violet gave no visible 
image upon screen. 

Same as No. 2. The addi- 
tion of blue to red m.*vde 
no perceptible differ- 
ence. 

(1.) With all ordinarj- 
illutpination, for recom- 
bined spectruni and for 
combinations of red and 
green and of yellow and 
blue. (2.) With strong 
direct sunlight. 

Blue-green and purple 
very conspicuous ; aU 
other colours compara- 
tively feeble. 



The weakness of the pulsative image of yellow is remarkable, and 
cannot be readily explained. If a yellow colour-patch is formed by 
^Dihining red and green rays, and the image is then put slightly out 



Tlie Solar Activity 1833-1900. 283 

of focus by moving the screen 3 or 4 cm. nearer to the lens, there 
appear two patches, one red the other green, which overlap one 
another, the part common to both being yellow. In the pulsative 
image the red and green become respectively blue-green and purple, 
while the overlapping portion is almost colourless. Possibly both the 
pulsative colours are less blue than they should be, with the result 
that their combination produces white or grey. 

The difficulty of forming a satisfactory pulsative image from blue 
and violet is no doubt to be accounted for by the superior persistence 
of those colours. With stronger luminosity than can be obtained by 
the method of projection or by the use of pigments this difficulty is 
diminished, for then the greater part of the luminous impression 
vanishes more quickly. 

Though the work of which an account is given in the present paper 
has occupied a large amount of time, it is obvious that the subject is 
far from being exhausted. Several doubtful points remain to be 
cleared up and apparent discrepancies reconciled, while of a number 
of remarkable phenomena which presented themselves no mention at 
all has been made. With more refined apparatus than that at present 
at my disposal, similar methods of experiment might be expected to 
yield important contributions to the theory of colour-vision. 



" The Solar Activity 1833-1900." By Wiluam J. S. Lockyer, 

M.A., Ph.D., F.E.A.S., Assistant Diiector, Solar Physics 

Observatory, Kensington. Communicated by Sir Norman 

Lockyer, K.C.B., F.R.S. Received April 29,— Read May 23, 

1901. 

Inlrotbidion. 

A close examination of the curves representing the varying amount 
of spotted area on the Sun's surface, shows that no two successive 
cycles are alike either in form or area. The indiWduality of the cycles 
seems, on further inspection, to be repeated after a certain period of 
time, and this peculiarity, coupled with a like variation in the curves 
representing the variations of the magnetic elements, and with suspected 
cycles of change in various terrestrial phenomena, suggested a new 
investigation of the whole subject. 

The object of this commiuiication is to place before the Royal 
Society the first results which an examination of the various records 
has furnished. 

Dr. Rudolf Wolf,* of Zurich, from a study of the sunspot observa- 
tions made up to the end of 1875, drew attention to the facts, to use 

• * Mem. B. Astron. Soc.,* toI. 4a, p. 200. 



286 Dr. W. J. S. Lockyer. 

his own words, that " la frequence des taches solaires persiste k changer 
periodiquement depuis leur d^couverte en 1610; que la longueur 
moyenne de la p^riode est de 11^ ans, et que cette mdme p^riode satis- 
fait aux changements de la variation magn^tique, et mdme de la 
frequence des aurores bor^Ies." 

Dr. Wolf was careful to point out that it was only the mean lengUi 
of the solar period that covered a period of 1 1^ years, and that the real 
length of any one period might differ from this value by as much as 
two years. The form in which he stated this result* was 

T = 11-111 ± 2,030 (als Schwankung) ± 0,307 (als Unsicherheit) ; 

where T represented the length of the period, ± 2,030 the variation 
from the mean value, and ± 0,307 the probable error of -the deter- 
mination. 

His attention was also drawn to the fact that the times of maxima 
flid not occur a constant number of years after a preceding minimum, 
and he was led to determine the viean time of occurrence of the maxi- 
mum after the preceding minimum and of the minimum after the 
preceding maximum, giving the mean intervals as 4*5 and 6'5 years 
respectively. 

Further, he at first concluded that the total spotted area for each 
period was nearly constant, but, as he later remarks, t this view could 
not be held, as these quantities not only varied but indicated " eine 
bestimmte Gesetz-massigkeit." The length of the period of this varia- 
tion he gave as about 178 years, which covered practically sixteen 
ordinary sunspot periods. ("11,1111 x 16 = 177,7777.") 

Somewhat later Dr. "Wolf was led to suggest a shorter period of 
55*5 years, which comprises about five ordinary eleven-year periods. 

In a recent paperj Professor Simon Newcomb has published the 
results of his investigation of the irregularities in the successive sun- 
spot periods, using as a basis Dr. Wolf's numbers up to the end of 
1872, and the spot areas as derived from the Greenwich reduction of 
the solar photographs taken daily at Greenwich, Dehra Dun, and 
Mauritius. 

The final conclusion at which he arrives is simimed up in the follow- 
ing paragraph : — 

** Underlying the periodic variations of spot-activity there is a uni- 
form cycle unchanging from time to time and determining the general 
mean of the activity." 

Professor Newcomb mentions, however, no length of period for this 
cycle, but speaking of its origin he remarks, " whether the cause of 
this cycle is to be sought in. something external to the Sun or within 

• ' Astron. Mittlieil./ Wolf. 187 ; p. 40. 
t ' Astron. Mittheil./ 1876, p. 47 ft 9eq, 
t ' The Astro-Physical Journal,' voL 18, No. 1, 1901, p. 1. 



The Solar Activity 1833-1900. 287 

it ; whether, in fact, it is in the nature of a cycle of variations within 
the Sun, we have, at present, no way of deciding.** 

In the investigations on periods of solar activity most workers have 
relied simply on Wolfs numbers, which are given by him back to the 
year 1749. Any one acquainted with these knows that from the time 
.^f/sf^maiic observations of the Sun's surface were commenced by Hof rath 
tSchwabe (1833), these numbers agree very closely with the actual facts; 
but before that date, the numbers are based, not on facts alone (which 
were not very numerous), but on a system of " meaning,"* suggested 
by the results of the observations from 1833 to 1876. 

Although then Dr. Wolf was able to present us with a ciu-ve dealing 
with the spotted area from 1749, it was decided for the present commu- 
nication to limit the discussion to those relative numbers which are 
based on the actual systematic observations since 1833. This neces- 
sarily restricted the investigation to a comparatively short number of 
years, namely, sixty-six (1833-1899), but it was thought that any 
variations detected, if greater than any which might be justifiably 
considered errors of obser^'ation, would be based on sotmd facts, and 
not on uncertain data. 

The important magnetic results obtained from a discussion of the 
Greenwich Observations by Mr. William Ellis, t placed at my disposal 
a most valuable check on any variation that might be obtained from 
the sunspot curves, Mr. Ellis having shown that the curves for the 
magnetic elements are in almost exact accord with those of the sun- 
spots obtained by Dr. Wolf. In this connection Mr. Ellis writes^ : 

'^ Considering that the irregularities in the length of the siuispot 
period so entirely synchronise with similar irregularities in the magnetic 
period, and also that the elevation or depression of the maximum 
points of the sunspot curve is accompanied by similar elevations and 
depressions in the two magnetic curves, it would seem, in the face of 
8uch evidence, that the supposition that such agreement is probably 
only accidental coincidence can scarcely be maintained, and there 
would appear to be no escape from the conclusion that such close cor- 
respondence, both in period and activity, indicates a more or less 
direct relation between the two phenomena, or otherwise the existence 
of some common cause producing both. The sharp rise from minimum 
epoch to maximum epoch, and the more gradual fall from maximum 
epoch to minimum epoch, may be pointed out as characteristic of all 
three curves." 



* For Wolf's method of *' meaning " see * Astronomische Mittheilungen,* Ton 
Budolf Wolf, Zurich, 1876, p. 89 et seq. 
t «Boy. Soo. Proc./ toI. 63, p. 64. 
J Ibid., p. 70. 



288 



Dr. W. J. S. Lockyer. 



Th€ Sumpot and Magnetic Epochs employed. 

As this paper deals mainly with the times of minima and maxima 
of both the sunspot and magnetic curves, it was necessary to utilise 
the results obtained from curves which had been " smoothed," as the 
original curves are of a subsidiary oscillatory character, especially at 
maximum. 

The sunspot curves just referred to are reproduced in fig. 1. They 
are so arranged in order of date that each individual curve can be 
examined separately. The times of succeeding mimma are arranged 
vertically under each other, so that any variation as regards accelera- 
tion or retardation of the following maxima, and any inequality in the 
length of the period minimum to minimum can be seen at a glance. 

Up to the sunspot maximum of 1870-6 Dr. Wolf has published* 
the dates of these epochs, and these are utilised here. The more 
recent epochs have been brought together by Mr. £llis,t and these 
complete the data available up to the last epoch, namely, the maximum 
of 18940. 

Each of these epochs is indicated in fig. 1 by a short arrow with 
the corresponding dates. The magnetic epochs here used are those 
published by Mr. Ellis in the paper just mentioned, and obtained from 
curves smoothed similarly to those of the sunspot curves. Unfortu- 
nately the observations he discussed only commenced in the beginning 
of 1841, so that comparisons cannot \ye made previously to this date. 

The smoothed curves obtained by Mr. VAlis are not here reproduced, 
but they will be found in his valuable paper J published in 1880. 

Th>e Sunspot Curves, Minimum to Maximum, 

In the following table are brought together the dates of the epochs 
of maxima and minima : — 



Sunspot epoc^hs (Wolf). 
Minimum. Maximum. 



Maximum 
minus 

minimum 
years. 



(1) 


1833 -9 


1837-2 


3-3 


(2) 


1843-5 


18481 


4-6 


(3) 


1866 I 


1860 1 


4 1 


(4) 


1867 -2 


1870-6 


3-4 


(5) 


1879 \ 


1884-0 


5 


(6) 


1890-2 

1 


1894-0 


3-8 
Mean 4 03 



• ' Mem. R. Astron. Soc.,* vol. 43, p. 202. 

t * Roy. Soc. Proc ,* toI. 63, p. 67. 

J ' Phil. Trans.; 1880, Part II, Plate 22. 



The Solar Activity 1833-1900. 



289 



If these figures in the last column be utilised as orclinates and the 
time element as abscissae, the cm*ve in fig. 2 (curve B) is produced. The 
peculiarity of this curve is that we have a very rapid rise to a maximum 
in 1843, and slow fall to the minimum in 1867. This is followed 

Fia. 1. 





T 

1 




T 




T 




T 

A 


1^ 


T 












"T 




"T 

A 












rr 




1 


" 1 






\ 






Y§i 


y^ 








t. 


T 


\ 










































a^ 


















L^ 


\ 








































'M 












y' 








\ 








































'M 












r 
















































rsB 
























/Ti 


s^ 


































^itl 




















A 




\ 




\ 




























^ 


ni 


'« 


















J 


L 


«-/ 


\ 




\ 


L 


























i 


m 


-ad 








i 










/ 








\ 




\. 


^ 
























t\ 


x> 


• « 








7 










/ 










\ 




V 


•\ 
























90 


-JC 






J 


/ 










' 










\ 


\ 




\ 




s, 






















njn 




^ 


J 








y 


^ 














X 


^^ 


^ 






N 






^ 












^Q 


f 










J 


f 
























-N 




>a 


**- 


» 












so 


36- 


y«a 


A^ 






/ 


^ 




/ 


^' 


'^ 


'N 




















N 
















t& 


»■! 








/ 






i 




fS 


ibo-^ 




\ 


\ 


















\ 














so 






1-^ 


^ 








j 


1" 


\ 








V 


s 




















N 












Xin 


t 










/ 


\ 


)\ 












^ 


k 


















V, 


■r 






lOj 


^ 


i&* 


5-6 ' 






J 


/ 


/ 






"^ 












v_ 


-^ 




k 














T 




ttO 




s^ 










/ 




( 






^ 




















N 


%^ 














too 




tO' 








/ 


















\ 


















s 






/ 






WQ 






, 


^-. 


^ 




















\ 




















V 


r' 








SB 






I 








/ 


















\ 




















L 








M 














f 


















\ 


-> 


























W 




«0 








/ 
























\ 
























4C 




'M 






J 
















^ 












\ 






















S£f 




■/u 




J 


/ 








_^ 






/ 


1 


\ 




























J 


^ 


KO 




■^ 


f 


^ 








^ 


/^ 




V- 




foe 


f*o 


^ 


N 
















<^ 






^ 




f\ 




■-40 


^ 


tt 






/ 




















\ 




















I 








tO' 


■JC 








/ 






X 




f 


s. 












\ 
















n 


^ 


' 






ao 


■to 






./ 


/ 


_/ 


/ 




i 


»* 


^ 


V 












V 
















7 








m 


-AJ 


H^ 


^ 


/ 




/ 














V 


^. 






















Hf^ 


/ 








w 




1 






1^ 


















\ 






















r 










fft 






\f.0 


: 

i 


/ 


















































so 








/ 




















































to 






^ 






















































to* 







7T 














.^ 


-J 










^ 


^ 


_^ 






_ 




















m 



by a similar rapid rise to the next maximum in 1879 and a gradual 
fall as far as observations at present indicate. 

The curve thus indicates that there is some law at work which 
introduces a secular variation by retarding the siUispot maxima in 
relation to the preceding minima. 



290 



Dr. W. J. a Lockjer. 



The period of this retardation can be deduced by taking the 
interval between the times of maxima or minima of this secular 
variation curve. By considering the minima, f.e., from 1833*9 to 
1867*2, we have a period of 33*3 years, and if we take the maxima 



Fio. 8. 



m 

4 


r 


J 


p 


J 


a 


4 


f 


J 


p 


_fl 


a 




r» 


J 


p 


m 


p 


m 


7 


^ 


MASAm 








— *i 






















































^ 
















— 


SUNSPOT i^rto. 








































cu«vt. ^ 












\ 








^ 


\ 




\ 




A 




A 








lYIAatlf MCANU ^^ 






aj 




, 


\ 




f\ 


s 


/ 


V 




\ 




^ 




\ ^ 


L 






900'- 










J 


1 


V 




\ 


^ 


^ 




\ 


SiJ 




^ 




\ 






0- 










































o 














rffi 














/■ 


N 












6UNSTOT 












J 


r^ 




•n 


fc. 






i 






V 










CllRVC* ^^ 






B. 






/ 








> 


s 




/ 






\ 


s 










j> 








« 
















^ 




























*^ 


^ 


V 










('^ 


N 












MAQNETIC 
CURVE, 


' 
















^ 


sj 






1 






\ 














c 
















\ 




1 








s 










>a< 






















s^ 




^ 








'*V 


■ 




$0* 










» 




•J 


V 












/^ 


\ 


s 










TOTAL SUUSPOT -^ 
















> 


L 








i 






>S 


\ 








AREA5. 






fi< 












N 
















\ 








{M,n l*eRiOQJ 


























/ 










\ 






(S. p. 0. PiuiiCTioitj ^SO- 






















V 


«^ 














^ 




MO-. 










































brUckn&r'5 

^1 iMATr /i- 




























/" 


























/^ 




■> 








J 
















VARtATlOHS. 








^j. 




/ 








\ 




/ 


















aAlNPALL. .j^ 


Hi 




E. 




^p^ 


/ 




^ 




\ 


L 


( 


















i.atauLAAc oeoicTCL 


-A 














{^ 


> 




*w 






^ 


■^ 
























j 






^ 






> 














1 


M. ** tf I 






r. 


II 






/ 






\ 




/ 








" 






L 


1 — ■ 


Mfl- 


^ft 








% 


^ 


f 






. > 


Sii 


r 










































/^ 


X 


r 






u 


— 


3. WHOLE tAHTK. ^. 






-a< 








y 


i^-» 


K 
^ 








^ 






















^3 




J 


f 






\ 




/ 
















— 


-«- 


^^ 






_ 


::^ 


^ 


_ 




U 





















at 1843*5 and 1879*0 we obtain 35*5 years. The mean of these two 
values gives a period of 34*4 years. 



The Magnetic Curves. Minimum to Maximum, 

Mr. Ellis's values for the dates of the magnetic epochs were investi- 
^ted in exactly the same way as the sunspot epochs were examined. 



Tlie Solar Activity 1833-1900. 



291 



It may be again mentioned that as the observations he reduced only 
l)egin in the year 1841, no comparison can be made with the epochs of 
1833-9 and 1837-2. 

Forming the table of maximum minus minimum as before and adding 
in the last column the values of maximum minus minimum of the 
simspot curves from the previous table for the sake of comparison, we 
have as follows : — 



Magnetic epoclis (Ellis). 


Maximum minu9 minimum. j 


j Minimum. 


Maximum. 

1848-55 
1860-40 
1870 -85 
1888*90 
1893*75 


Magnetic. 


Sunspots. 


(1) - 

(2) 1843-60 
(8) 1856*15 

(4) 1867*55 

(5) 1878-85 

(6) 1889 75 


4-95 
4-25 
8*80 
6-05 
400 • 


88 ! 
4-6 
4-1 

8*4 1 
6-0 

8*8 * 
1 



The nearly complete parallelism of the numbers in the last two 
columns indicates their strict accord with each other. 

The curve showing this magnetic variation is given in fig. 2 
(curve C), and it is practically a counterpart of ciu've B. 

The value for the length of the period, as gathered from the interval 
between the two maxima of this curve at 1843*60 and 1878*85, is 
35*25 years, which does not differ very much from the value deduced 
from the maxima of the corresponding sunspot curve, namely, 35*5 
years. 

Sunspot and Magnetic Ounces Combined, Minimum to Maximum. 

By combining the values of the intervals (minimum to maximum) 
from both the sunspot and magnetic curves, their mean values can be 
determined as shown in the last column of the following table, the 
general mean for the whole period being added below : — 



From minimum occurring 


about 


(^) 


1833 


(2) 


1843 


(3) 


1836 


<4) 


1867 


<>) 


1879 


(6) 


18kK) 



Mean of sunspot and magnetic 
intenralfl in yean. 



8-8 

4*77 

4-17 

8*85 

6-25 

8-90 

Mean .. 4*12 



292 



Dr. W. J. a Lockyer. 



Siiice these numbers cover more than a complete cycle» thqr may Im 
combined so that mean values for the intervals minimum — m a Timnm 
may be obtained for those epochs when the intervals have their 
largest, intermediate, and smallest values. Thus in the years 1843 
and 1879 the maxima followed the minima in 4*77 and 5*25 years 
respectively, the mean interval thus being 4*91 years. For the inter- 
mediate stage (combining (3) and (6) ) a value of 4*03 years is fooncl, 
while for the minimum interval combining (1) and (4) this value 
3*32 years. 

The adtud epoch of maximum relative to (he preceding minimum oseUlates 
about the mean vaiue^ its greatest ampUtude being in the mean 0*8 year. 



The Total Sunspot Areas. Minimum to Minimum. 

The great divergence in the amount of spotted area during consecu- 
tive eleven-year cycles suggested that perhaps this periodical riBtarda- 
tion of the maxima with respect to the each preceding minimum might 
be accompanied by variations following the same law. It was observed 
that when a maximum occurred comparatively soon after a minimum, 
the tendency of the whole spotted area for that sunspot period was to 
be increased. 

I have been permitted for this inquiry to utilise the values which 
have quite recently been obtained at the Solar Physics Observatory 
from a new reduction of the curve representing the solar spotted area, 
and these values, representing the total spotted area in millionths of 
the Sun's visible hemisphere from minimiun to minimum, are given in 
the last column of the following table : — 



Sunspot period from 


Total spotted area. 


' From minimum 

1 

1 


to minimum. 


1888-9 
1848-5 
1856-0 
1867*2 
1879-0 
1890-2 


1848-5 
1856-0 
1867-2 
1879-0 
1890-2 
1901- + 


86 008 
85 201 
111 514 
126 188 
78 858 
96 734 + 



The figures in the last column show a similar but inverted sequence 
to those in the previous tables. Thus from minimum 1867**2 to the 
following maximum 1870*6 we have a short interval of time; the 
spotted area for that period is greatest. If the above values in the 
last column be graphically shown, and the ciu-\'e inverted, we have a 
remarkable similarity (fig. 2, Curve D) to the two curves B and C 



Tlu Solar Activity 1833-1900. 293 

previously described. Special attention is called to the slow fall from 
1843 to the minimum at 1867*2, and the rapid rise to 1879*0. 

It may be remarked that the value for the total spotted area for the 
period 1833'9 to 1843*5, the earliest value in point of time dealt with, 
is not quite in harmony with the other values. It is probable that 
•iilthough at this period the time of maximum and minimum could be 
^accurately determined, the values may be too small owing to the fact 
that Schwabe's observations were not made at that period quite on a 
uniform plan. Mr. Warren de la Rue and Professor Balfour Stewart* 
•on this point wrote : — 

" By the commencement of 1832 Schwabe had matured his system 
to such an extent as to give, no doubt with considerable precision, the 
«hape and area of each group ; although it was not until the commence- 
ment of 1840 that he finally fixed upon the system of delineation, 
which he henceforth pursued up to the time when he discontinued his 
■observations." 

The above suggestion seems to be borne out by the reduction of 
sunspot photographs secured at the Wilna Observatoty, where it was 
found that the maximum of 1870 was of about the same order as that 
-of 1836. The Report of the Wilna Observatory for the year 1871 
refers to this point in the following termst : — 

" The curve traced from oiu* obser\'ations about the last maximum 
period of spots (1870) is one and a-half times as high as that of the 
three most recent periods, i.e,, the total sum of the areas of the spots 
About the maximiun period of 1870 was one and a-half times larger 
than during the last thirty-six years. This marked difference obliged 
us to enter upon a double verification of our calculations, but we did 
not discover any appreciable errors." 

With reference to the value given in the last line of the last column 
of the table, although this is probably very near the truth, it is yet 
impossible to state the date of the present minimum (1901*2 probably). 
All the areas recorded since the minimum of 1890 and up to the 
beginning of 1900 have been employed; this value is, however, 
only slightly below the real one, so that a -h sign has been printed 
against it. 

If, therefore, these two facts be kept in mind, it will be seen that the 
inverted total sunspot-area curve can be considered practically an exact 
counterpart of the other two curves. 

The Total Area of the Magnetic Curves. From Minimum to Minimum. 

The remarkable similarity between the magnetic and sunspot curves, 
especially in the later years when such observations are naturally more 

* * Beport of the Committee on Solar Fhjtios, 1882.* Appendix B^ ^« 71 . 
t Ibid,, Appendix D, p. 154. 



294 



Dr. W. J. a Lockyer. 



accurate, made it unnecessary to ducuBS the variation (as shown in the 
ease of the sunspot areas) regarding the total areas of the corvee from 
minimum to minimum. This variation seems to be more pronounced 
in the curve representing the horizontal force than in that representing 
declination. 

Lm^ ofihe Period of FariaUm Oius ddemmed. 

In summing up the values obtained for the length erf the secular 
period of variation under discussiony we form the following taUe : — 





mftTimnm, 
Yeut. 


Muumimi to 

BiiiiiiiiiiiD. 

Yeare. 


i Santpoi onrro ...«••• 


86*6 

85-26 

85-5 


tS-8 


1 Msgnetio „ 






Means 


86-41 


38-8 




Combined mean .... 


34-89 



The observations thus lead to the conclusion that underlying the ordi- 
nary sunspoi period of about eleven years iheie is another cycle of greater 
lengthy namely^ about thirty-five years. 

This cyde not only alters the time of occurrence of the maxima in relation 
to tlie preceding minima, but catises changes in the total spotted area of the 
sun from one eleven-year period to another. 



The Variation in the Length of the Interval Minimum to Minimum. 

Having found a definite variation in the length of the interval mini- 
mum to maximum, the curves show a further variation when the 
interval — minimum to minimum — was considered. An attempt was 
therefore made to see if any law could be traced, but the inquiry only 
led to a negative result. 

The following table contains the values for the periods — minimum to 
minimum — and the differences from the mean, for both the sunspot and 
magnetic curves individually and combined. It will be seen that the 
alternation of signs in the columns showing the sunspot jdifferencee is 
not corroborated by the magnetic differences, but when the combined 
values are used this oscillation for consecutive periods is still em 
evidence: — 



The Solar Activity 1833-1900. 



295 





Sunspots. 


Magnetics, 


Combination. 


Bfinimam 














! beginning 

! in the 


Minimum 


, Differences 


Minimum 


Differences 


Minimiini 


Differences 


1 year 


to 


from 


to 


from 


to 


from 


■ 


minimum. 


' mean. 


minimum. 


mean. 


minimum. 


mean. 


' • 


Years. 


Years. 


Years. 


Years. 


Years. 


Years. 


1 1833-, 
1 1843-'t 
i 1866J 
j 1867^1 

1 1890-* 


9-6 
12-5 


-1-7 
+ 1-2 


12*66 


+ 1-0 


9-6 
12-52 


-1-7 
+ 1-82 


11-2 


-0-1 


11-40 


-0 14 


11-80 


+ 0-10 


11-8 


+ 0-5 • 


11-30 


-0-24 


11-65 


+ 0-86 


11-2 


-0-1 


10-90 


-0-64 


11-06 


-0-16 


Means.. 

1 


11-3 


— 


11-64 


— 


11-20 


— 1 



Although there is a suspected variation in the length of both the 
magnetic and sunspot periods (reckoning from minimum to minimum), 
which increases and decreases in alternate eleven-year periods from 
a mean value, the observations do not extend over a sufficient interval 
of time to allow a more definite conclusion to be drawn. 



Relation oftlie Sunspot Curve to the Light Cwve of rf Aquike. 

It is generally conceded that the spots on the surface of the Sun are 
the result of greater activity in the circulation in the solar atmosphere, 
and therefore indicate greater heat and, therefore, light. This being 
so, the curve representing the spotted area may be regarded as a light 
curve of the Sun. 

The Sun may thus be considered a variable star (1) the light of 
which (reckoning from minimum to minimum) is variable, with a mean 
value of about ll'l years ; (2) the epoch of maximum does not occur 
a constant. number of years after the preceding minimum, but varies 
regularly, the cycle of variations covering about 35 years. 

It is interesting therefore to inquire whether there be any other 
known star or stars which exhibit variations similar in kind to those 
given above. 

In the year 1896 I undertook the investigation of all the observiir 
tions, whether published or not, of the variable star rj Aquil» * which 
had been made between the years 1840 to 1894, numbering in all 
12,000. 

For the present inquiry the light curve of this star is of great 
interest, as its chief peculiarities are similar to those I have indicated 
in connection with the sunspot curve. 

Not only are the more rapid rise to maximum and slow fall to 

* 'Besullate aus den Beobaehtungen des verilnderlichen Stemes ti Aquilae/ 
Inaugural-Dissertation, UniTersit. Gottingen, 1897 (DulauaAdCo.,\Axv!^TC^« 



296 



Dr. W. J. S. Lockjer. 



minimum distinct features of the curve, but the periods (reckoning 
from minimum) vary slightly in length in the course of many mean 
periods. More important still, the time of occurrence of the maximum 
in relation to the preceding minimum varies to a comparatively large 
extent in the course of few mean periods. The facts arranged in 
tabular form sum up the information with regard both to the sunspot 
ciu^e and that of rf Aquilae. 

To facilitate the comparison, the different intervals of time con- 
verted into fractions and multiples of the sunspot (Q) and 17 Aquilae 
(P) periods are given in separate columns. 






3 g 

'2 g 



• ^ 



Light curve of 



Son. 



9 Aquilff. 



Mean ralue 

Period of variation 

Maximum variation 

from mean 



Yean. 

11*20 

Unknown 

dk>l-4 



Mean value 

; Period of variation 
I Maximum variation 
j from mean 



I 



4 *12 (about) 
34-8 „ 

±0-8 „ 



Q 



±>012Q. 



0-37Q 
3 10Q 

±0 07Q 



7d 4I1 14« 4 

±3»» 
2'« 5 
± 5»» 



= P 

2400 P 

0-017P 



0-3IP 
400P 

±0-03 P 



Fig. 3 is a reproduction of a set of light curves of the star 
V Aquila?, in which the dotted line and the two vertical wavy and 
oblique dotted lines passing through the points of maxima and minima 
indicate the variations of the times of maxima and minima. 

The curve for each group is the result of a combination of the oljser- 
vations made over a period equal in length to 100 mean periods (mean 
period = 172***2344) of the star. This whole set of curves is the 
result of a discussion which I made of all the observations of »; Aquil» 
made by one observer, Herr Julius Schmidt. 

Other Cycles of about Thirty-fu:f Years. 

Having found that, in addition to the well-known eleven-year period 
of simspot frequency, there is another cycle which extends over about 
thirty-five years, and which is indicated clearly, as has been shown, 
both by the changes in the times of the occurrence of the epochs of 
maxima and in the variations in area includetl in consecutive eleven - 
year periods of both sunspot and magnetic ciu'ves, it is only natural to 
suppose that this long-period variation is the effect of a cycle of dis- 
turbances in the Sun's atmosphere itself. 



T/ie Solar Activity 1833-1900. 
Fig. 3. 



297 




7 6 3 10 ir 



298 Dr. W. J. S. Lockyer. 

Such a cycle, if of sufficient intensity, should cause a variation from 
the normal circulation of the Earth's atmosphere, and should be indi- 
cated in all meteorological and like phenomena. 

It is not intended to go into any detail as regards such terrestrial 
variations, but it may be noted that much important work has been 
done on the investigation of changes in climate^ by Professor Eduard 
Briickner,* who expended immense labour during many years in the 
promotion of the inquiry. Professor Bruckner did not restrict his 
discussion to observations made over a small area or for a short interval 
of time, but utilised those made in nearly every part of the civilised 
world, and extending as far back in point of time as possible. Further, 
he did not restrict himself to the discussion of the observations of one 
or two meteorological phenomena, but examined critically all likely 
sources from which such changes as he expected could be detected. 
Thus he sought variations in the observations of the height of the 
waters in inland seas, lakes, and rivers ; in the observations of rainfall, 
pressure, and temperature ; in the movements of glaciers ; in the fre- 
quency of cold winters ; growth of vines, &c. 

The result of the whole of the investigation led him to the conclu- 
sion that there is a periodical variation in tite climates aver the whole earthy 
the mean length of thus period being 34*8 ± 0*7 years. 

It may be of interest to remark, that so convinced was Professor 
Bruckner of the undoubted climate variations that he deduced, and so 
certain was he that such variations could only be caused by an external 
influence, that he investigated Wolf's sunspot nimibers to see whether 
such a cycle was indicated. 

Misled by the long period of variation of sunspots of fifty-five yeiirs 
as suggested by Wolf, he was led to conclude that his climate variation 
was independent of the frequency of sunspots. He sums up his con- 
clusion in the following wordst : — 

"Die Klimaschwankungen vollziehcn sich unabhangig von den 
Schwankungen der Sonnenflecken-Haufigkeit ; eine 55-jahrige Periode 
der Wittenmg, wie sie der letzteren entsprechen wiirde, ist in unsoren 
Zusammenstellungen nicht zu erkennen." 

Nevertheless, he was led to make the }x)ld suggestion, that such a 
vai-iation as he sought must really exist in the Sun, but might possibly 
be independent of sunspots. He finally concluded that the climate 
variations are the first symptom of a long period variation in the Sun, 
which probably will be discovered later. 

In the light of the present communication Professor Bruckner's 
conclusions are of great interest, becaiise not only does the length of 

• * Oeographische AbhandluDgen Wien,' Baud 4, Heft 2, p. 155, 1890. " Klima- 
Schwankungen seit 1700 nebst Beinerkungen iiber die Klimaschwankungen der 
Dilurialzeit.*' 

t * Klimaschwankungen/ Bruckner, p. 242. 



Tht Solar Activity 1833-1900. 299 

the period, but the critical epochs of his cycle, completely harmonise 
with those found in the present discussion of the sunspot and magnetic 
curves. 

To illustrate more fully this connection, and to take only one case, 
namely, rainfall, the three rainfall curves* are reproduced in fig. 2 
(curves E, F, G). 

E and F represent the secular variations for what Professor 
Bruckner calls " Begulare Gebiete I und II,"t while curve E is the 
mean for the whole set of observations he has employed, and 
represents the secular variation of rainfall over the whole earth as 
far as can be determined. 

The comparison of these curves with those representing the simspot 
and magnetic results given above them, shows that when the epoch of 
maximum spotted area (curve B) follows late after the preceding 
epoch of minimum (1843, 1878), or when the spotted area from 
minimum to minimum is least (curve D), the long-period rainfall curve 
is at its maximum or we have a wet cycle. 

When on the other hand the maximum (ciure B) follows soon after 
the preceding minimmn (1867), and the spotted area for this cycle is 
at a maximum (curve D), the rainfall curve is at a minimmn or a dry 
cycle is in progress. 

It may also be observed that in a detailed investigation of the 
movements of glaciers, Professor Ed. Richter finds a cycle of thirty- 
five years. In his * History of the Variations of Alpine Glaciers,'! 
he sums up his results as follows : — " Die Gletschervorstosse wieder- 
holen sich in Perioden, deren Lange zwischen 20 und 45 Jahren 
schwankt, und im Mittel der drei letzten Jahrhunderte genau 35 Jahre 
betrug." 

Further he pointed out that the variations agreed generally with 
Bruckner's climate variations, the glacier movement being accelerated 
diuring the wet and cool periods. 

Another very interesting investigation to which reference must be 
made is that which we owe to Mr. Charles Egeson, who published his 
researches§ in solar and terrestrial meteorology just a few months 
before the appearcnce of Professor Bruckner's volume. Mr. Egeson 
not only finds a secular period of about thirty-three to thirty-four 
years in the occurrence of rainfall, thimderstorms, and westerly winds 
in the month of April for Sydney, but the epochs of maxima of the 
two latter harmonise well with the epochs of the thirty-five yearly 
I>eriod deduced in the present paper for sunspots. 

Thus he finds that the yearly numbers of days of thunderstorm 

• Briickner, ibid., p. 171. 
t Bniokner, ibid., p. 170. 

t * Zeit. d. Deuts.-Oeaterr. Alpen-Vereins,' 1891, Band 12. 
§ Egeson's < Weather System of Sunspot CausaUiy .* Hj^iie^ ,\^^. 
VOL. LXVIII. X 



300 Sir W, de W. Abney. On the Variation in 

attain their maxima values in 1839 and 1873, and those of the 
westerly winds in April in 1837 and 1869. As the secular variations 
of the sunspots have their maxima in 18372 and 1870-8, the agree- 
ment is in close accord. 

There seems little doubt that, during the interval of time covered 
by the present investigation, the meteorological phenomena, number of 
aurorse, and magnetic storms, show secular variations of a period of 
about thirty-five years, the epochs of which harmonise with those of 
the secular variation of sunspots. 

As we are now approaching another maximum of sunspots which 
should correspond with that of 1870*8, it will be interesting to observe 
whether all the solar, meteorological, and magnetic phenomena of that 
period will be repeated. 

Canehtmn. 

1. There is an alternate increase and decrease in the length of a 
sunspot period reckoning from minimum to minimum. 

2. The epoch of maximum varies reguhrhf vnth respect to the pre- 
ceding minimum. 

The amplitude of this variation about the mean position is about 
± 0-8 year. 
The cycle of this variation is about thirty-five years. 

3. The total spotted area included between any two consecutive 
minima varies regularly. 

The cycle of this variation is about thirty-five years. 

4. There is no indication of the fifty-five-vear period as suggested 
by Dr. Wolf. 

5. The climate variations indicated by Professor Bruckner are 
generally in accordance with the thirty-five-year period. 

6. The frequency of aurorse and magnetic storms since 1833 show 
indications of a secular period of thirty-five 3'ears. 



"On the Variation in Gradation of a Developed Photographic 
Image when impressed by Monochromatic Light of Different 
Wave-lengths." By Sir William de W. Abxev, K.C.B., 
D.C.L, D.Sc, F.R.S. Eeeeived March 26 —Bead May 2, 
1901. 

Introiluctoi'i/. 

When a series of small spaces on a photographic plate are exposed 
tx) a constant light for geometrically increasing times, or for a constant 
time to geometrically increasing intensity of illumination, the spaces 
so exposed will on development show deposits of silver of different 



GrradcUion of a Developed Pliotographic Image. 301 

opacities. These opacities may be measured and noted 21s "trans- 
parencies," "opacities," or "densities," the last being the - log 

transparencies and the opacity (These definitions of 

transparency 

opacity and density are those given by Hurler and Driffield, and are 
generally understood as such in photographic literature.) Where 
varying time exposures are given, it is convenient to start with some 
unit of time, such as 10 seconds for the exposure of the first small 
space on a plate, to double this exposure for the next small space, and 
so on. When the measurements of transparency or density are made, 
and the curve has to be plotted, the scale for the abscissa is conveni- 
ently the niunber of the exposure — that is, the time of exposure in 
powers of two. The ordinates are then set up as transparency of 
deposit, total transparency being 100, or as densities which give the 
absolute light cut off in terms of common logarithms. The curve 
joining these different ordinates is in both cases approximately a 
straight line for some distance, and, at each end, tends to become 
parallel to the scale of abscissse, and this straight portion is taken as 
representing the gradation of the plate. If the same plate be thus 
exposed to different monochromatic lights, and the images developed 
together and the density measured, it is easily seen from the plotted 
curves if the " gradation " of the plate is the same in each case, since, 
if they are, the straight portions of each curve should be parallel. 

[It may be noted that the less steep the gradation of a plate, the 
greater will be the extremes of lights and shades in an object or view 
that will be shown in a print, as the blackest tone obtainable on it 
reflects about 3 per cent, of light. For this reason in sun-lighted 
views, a plate showing a flat gradation should be employed, whilst in 
those illuminated by a cloudy sky, a plate giving a steep gradation 
should be used.] 

When obtaining the three negatives for three-colour printing where 
the object is photographed through an orange, a bluish green, and a 
blue screen, if there is much change in gradation caused by the 
difference in the colour of the light reaching the plate, the true render- 
ing of an object in its natural colours becomes an operation of extreme 
difficulty. It was with a view to ascertain if some of the difficulties 
which have been encountered in this process were due to difference in 
gradsition caused by the different coloured screens, that this research 
was commenced some three years ago. Nearly two years ago, in an 
article in 'Photography,' I indicated that a variation in gradation 
due to difference in the monochromatic light in which the exposure 
was made did exist, and some six months ago Mr. Chapman Jones, in 
a paper communicated to the Royal Photoghiphic Society, independ- 
ently annoimced the same result from experiments made principally 
with orthochromatic plates with light passing throw^Vi \^\Q\3&^0i!(svn^ 



302 Sir W. de W. Abney. On the VariaiiM in 

media, and he generalised from his experiments, that the smaller the 
wave-length, the less steep was the gradation, the ultra-riolet nys 
giving the least steep, and the red the most steep gradation. My 
experiments, which had at that time been partially completed, did not 
bear out this generaUsation to the full when pure sUver salts were 
used; and my subsequent measiwements with them show that the 
least steep gradation is tJiat given by the monochromatic light to 
which the simple silver salt experimented with is most senutive, and 
that the gradaticxi becomes steeper as the wave-lengths of light em- 
ployed depart in either direction in the spectrum from this point, the 
steepest gradation being given by the extreme red. The case of ortho- 
chitnnatic plates in which is a complex mixture ot silver salt and dye, 
is necessarily less simple, involving considerations of the looaUties in 
the spectrum to which the dye or dyes, together with that of the silver 
salt, are most sensitive. For this reason the simple salts have been 
experimented with in preference to the more complex organic com- 
pounds. 

Mdlukh of Experimenting, 

As pointed out in the opening paragraph, there are two ways of 
experimenting, one where the illumination is constant, the times of 
exposure being altered, and the other in which the time of exposure 
is constant, and the illumination is altered. This last is the condition 
under which an image in the camera is photographed. It might 
appear that both methods should give identical quantitative results, 
but it was more than probable that they would not do so, from 
the experiments that I had previously carried out with these two 
methods with ordinary white light. 

The first set of experiments were with fcxed time of exposure and 
varying intensity of light. To obtain the varying intensity, a photo- 
graphic plate was exposed to white light, the parts exposed being 
limited to an area having the form of a triangle with the top cut off* 
at the apex, the two sides being radial to the centre of the plate. The 
enclosed angle was about 20"*, so that by turning the plate round its 
centre, twelve different spaces would be exposed. After the plate had 
been developed with ortol or ferrous oxalate, fixed, washed, and dried, 
the intervals between the exposed parts were blocked out. The 
opacities were then ready for measurement. Fig. 1 is a reproduction 
of the " star " graduated opacities. 

Measurement of Star Opacity with dijffeieni Colours, 

It became necessary to see whether the deposit obstructed light 
equally for each ray of the spectrum, and the following arrange- 
ment was adopted.^ The colour patch apparatus which I have 



Gradation of a Developed Photographic Image. 303 



Fig. 1. 




described in previoviB papers on Colour Photometry in the * Philo- 
sophical Transactions/ was brought into use. A ray of the spectrum 
was allowed to issue through S, fig. 2, and after piissing through 



Fig. 2. 



Sr 



"-'--4 



a lens formed a square patch of monochromatic light on C, a 
white screen. In the path of the beam X a plain gla«8 mirror, Mi, 
was inserted, which deflected a certain percentage of the beam Y 
to M'i, a silvered glass mirror, which in its turn reflected Y so as to 
fall on C. A rod, li, placed in proper position, caused two oblongs of 
the direct and reflected beams to fall side by side on C. Two sectors, 
A and B, were placed in the paths of X and Y respectively. The 
apertures of A could be opened or closed at pleasure whilst the disc 
was rotating. A red ray of the spectrum first came through 8, and 
the aperture in A required to equalise the two adjacent patches of 
light was noted. Other rays of the spectrum were similarly dealt with, 
when it was found that the aperture in A remained unaltered, showing 
that within the limits of error of observation the pereeuXAig^ oil ^^^^^- 



304 



Sir W. de W. Abnej. On the Variaium w 



tion from Mi remained the same for all rays. The 8tap«haped opaei- 
ties were then introduced into the beam X at D, and when nocflssary, 
B was rotated with known and fixed apertures, and the patehes of 
light again made equally bright by means ci A* It was found that 
the apertures of A varied as the diflbrent spectrum colours passed 
through the deposits, forming the graduated star. Using the same 
scale for the spectrum as used in my former papers (B is 61-3. 
Li 59*7, C 581, D 56, E 39*8, F 30*05, Li 228, O 112), the absorp- 
tions were calculated for the whole spectrum. It was found that the 
coefficient of absorption (obstruction) of white light and at the ray 
26*8, coincided, and taking this as unity (for a purpose which will be 
seen presently) the coefficients of the other rays are as follows : — 

Table L 



Scale niunbar. 


Absorption. 


59 to 49*8 


0-87 


47-6 


0-90 


42-9 


0-92 


38-3 


0-93 


83-7 


0-95 


29 1 


0-97 


26-8 


100 


22-2 


1-02 


17 6 


102 


8-4 


108 



The trHiisparencies of the different parts of the star to lamplight 
were measured and calculated out in powers of - 2, the light trans- 
mitted through the part on which no deposit appeared being taken as 
zero. The following are the transparencies as calculated : — 





Table IL 


Opttcitr. 
No. 1 




Transparency in 
powers of — 2. 







» 2 




0-38 


.. 3 




0-76 


„ 4 




105 


» 5 




1-73 


„ 6 




2-36 


.. 7 




3-6 


.. 8 




4-16 


M 9 




6-2 


.. 10 




6-9 


M 11 




6-9 


» 12 




8-9 



Gradation of a Developed Photographic Iniagc. 305 

111 percentages the transmission of white light through No. 1 and 
No. 12 is therefore 100 and 0*477 respectively, which allows a suffi- 
ciently wide range of intensity to be investigated. The above numbers 
represent then the absorption of white light, and also that of the blue 
light coming through a slit placed at 26'8 of the scale of the spectrum. 
To obtain the scale in powers of - 2 for the other rays they must be 
multiplied by the factors given in Table I. 

The star can now be used for the purpose for which it was prepared. 

Experiments with Fixed Time of Exposure. 

With the colour-patch apparatus a patch of red light was thrown on 
the star backed by a sensitive plate, which could be revolved round 
their central point in a special dark slide, and exposure was made to 
the patch with the plates rotating for the time it was judged necessary 
to cause an impression of each intensity of light. The rotation was 
deemed necessary in case the light coming through the thick part of 
the prism was more absorbed than that coming through the thin part. 
The plate was then removed from the slide, and a scale of gradation 
impressed on a part which had been covered up during the previous 
exposure. The source of light used for this scale was an amyl-acetate 
lamp placed at 4 feet from the plate, and the time was doubled for 
each successive exposure. On development there was an image of the 
star, each space in different densities, and alongside a graduated scale 
of densities with which the star densities could be compared. Other 
plates were exposed to other rays of the spectrum, those selected being 
at the scale numbers recorded in Table I. As each separate image of 
the star could be compared with the scale of gradation given by the 
amyl-acetate lamp they could be compared with one another. 

Spectrum Sensitiveness of Bromo-iodide of Silver. 

The first sensitive salt of silver with which experiments were made 
wiis the bromide of silver, to which a small quantity of iodide of silver 
had been added. A spectnun of the electric arc light was impressed 
on the gelatine plates prepared with this salt, and the sensitiveness to 
the various rays ascertained by the plan given in a previous paper.* 
(To facilitate a comparison of the results given in this paper with 
the curve of sensitiveness the latter is drawn on the prismatic scale as 
given above.) 



* **The eSect of the Spectrum on the Haloid Salts of Silver/' Abney auil 
Edwards, * Roy. Soc. Proc.,' vol. 47. Bead DecembeT 12, l^*d« 



306 



Sir W. de W. Abney. (M the Variatum m 
Fio. 8. 



rlOO 




-^ -j|{}""tS ^io d Jo io" 
Scale cf SpecCrum. 

The following table applies to the curve, fig. 3. 

Table III. 



Scale No. 


Sensitiveness. 


Scale No. 


Sensitiveness. 


42 


5 


12 


95 


44 


21 


8 


£2 


88 


35 


4 


80 


36 


50 





85-5 


34 


63 


- 4 


82 


32 


74 


- 8 


77-5 


30 


82 


-12 


73 5 


28 


89 


-16 


69 


26 


96 


-20 


64 


24 


99 


-28 


50 


22 


100 


-36 


29 


20 


99 


-42 


13 


16 


97 


-48 






The measurement of the densities on the plates was made by means 
of an arrangement by which the comparison light was transmitted 
through a graduated black annulus, whose thickness increased arith- 
metically with the number of degrees from the zero point. This 

^e the density measured on a scale of logarithms on a base due to 



J_^ 



Oradatian of a Developed Photographio Image. 307 

its coefficient of. absorption (obstruction). The mode of measurement 
has been described in other papers by myself and need not be repeated. 
As the ** star" opacities and the graduated opacity scale on each plate 
were measured with the same aimulus, it was unnecessary to reduce 
the measurements to densities which are usually taken in terms of 
common logarithms, or to transparencies in percentages of the initial 
light. 

Example of Experimeids, 

It will facilitate matters if one example of measures be given in 
detail, and the mode in which they are applied. The spectrum colour 
used was at the scale No. 56*7. The star with the plate in contact 
with it was placed in the dark slide, and so arranged that the square 
patch of monochromatic red light would cover the whole of the former. 
The only light which would penetrate to the plate was through the 
star opacities. The star and plate were made to revolve romid their 
centre in the slide by means of a spindle projecting outside, on which 
was a pulley that could be geared to an electromotor. Exposure was 
given for 65 minutes. No light was in the room except the red light. 
To make certain that the red light which fell on the prisms, and which 
illiuninated them to a certain small extent, had no effect on the plate, 
the slit S, fig. 2, was covered with red glass, which only allowed the 
red of the spectrum to pass. The plate after the first exposure was 
completed ; was removed and placed in a special slide, which allowed 
varying time exposures to be made on small square areas of the plate 
alongside that part which had been already impressed. The exposures 
were made to an amyl-acetate lamp at 4 feet distance, and were of 1, 
2, 4, 8, &c., units of time duration. The plate was developed with 
ortol developer, fixed, washed, and dried. It was then placed in the 
measuring apparatus, and the scale densities of the amyl-acetate lamp 
exposures and the star opacities measured. On looking at Table I it 
will be seen that the coefficient of absorption, as there shown, is 0*87. 
The numbers in Table II were therefore multiplied by 0*87 to give 
the scale for abscissa in powers of 2. The following measures were 
obtained (Tables IV and V). 

These results were plotted (fig. 4), and straight parts of both curves 
were compared. It will be seen that in the star opacities the curve 
cuts the abscissa 1 with an ordinate of 174, and this same ordinate is 
found on the scale curve at 2*65 in the abscissa. Again, the first has 
an ordinate of 63 at the abscissa 4, but the scale has abscissa 6*65 for 
the same ordinate. This shows that the exposures of the star would 
have had to be prolonged in both cases to have acquired the same 
density Jis the scale, but very unequally. We can find the unequal 
times necessary by subtracting the two abscissae from one another at 
each point, and expressing the inequality by a {raoXioiv^ 



308 Sir W. de W. Abney. On the rarioHon «» 

Table IV. Table V. 



Amyl-aoetate icale. 


Exposuroin 


Beftdingof 


powen of 2. 


Aimuluf. 




202 




189 




168 




145 




122 


6 


98 


7 


77 


8 


66 


BareglaM 


21 



"St»r-< 


Eypacitiei. 


Xntonnlriii 


Bflndingof 


powertof — 2. 


•oniiliis* 





202 


0-88 


197 


0-66 


187 


0-98 


178 


1-60 


166 


2-06 


186 


3 06 


97 


8*62 


77 


4-61 


89 


5-22 


80 


6 18 


26 


7-74 


_ 


BaraglaM 


21 



Fig. 4. 




^ 3 

QghC intenaiCi^s for'^SCdLrin powers of -£ . 
Time cf exposure fbr AmyL-AoksCe L^unp in pomrs of -a. 



Grradation of a Developed Photographic Image. 



309 



Thus:— 



or 



Star. 

1 = 

4 = 

3 = 

1 = 



Abscissa. 
Scale. 

2*65 (ordinate 155) 
7 -60 (ordinate 42) 



4-95 
1-65 



That is to say, the gradation of the plate when subjected to the red 
light is much steeper than whea subjected to the light of the amyl 
acetate, and that to produce the same slope the ratio of the times of 
exposure to red light would have to be shortened in the ratio of 1 : 1 *70 ; 
that is, if the exposure was doubled for the red light on each small 
space ; then to make the slope the same for the amyl-acetate light the 
successive exposures given with it would have to be 3*3 times. It must 
be recollected that the fii*st exposures required to give any deposit on a 
plate would be widely different, being far larger for the red light. 

liCsuUs of Mensures made. 

To avoid any white light with which the prisms were illuminated 
reaching the plate through the slits, the following absorbing media 
were placed in front of the slit at the places indicated. The times 
of exposure are also shown. 



Scale No. 


Exposure. 


Absorbing medium in front 
of sUt. 


56-7 


65 min. 


Stained red glass. 


54-4 


20 ,, 


>t II 


62 1 


5 ,. 


t* II 


50-6 


6 „ 


Orange. 


47-5 


8 „ 


Ijemon jellow. 


42 


2 „ 


Chrome green. 


38-3 


2 „ 


Peacock green. 


33-7 


10 sees. 


i> »i 


29 1 


H „ 


Blue dye. 


26-8 


12 ,. 


11 


22 2 


5 „ 


Gcbalt glass and blue dye. 


17 -(3 


5 „ 


fi II i« 


8-4 


4 .. 


Methyl yiolet. 



The following tables give the measured curves, and from them the 
gradations are found, as in the above example, the exposures given 
being as follows : — 



310 



Sir W. de W. Abney. On tks Fariatum in 






\ 

i 

1 


1 

s 
s 


i 


QD 


•i?Bnwtt 


ggaSSSS§l:gSg5: 


*itwwnet^Hti1 




S 


■-^■Mwa 


^£|S2&SSSS?&a 


•A^imi»im^il8ti 


O O O «M ^ M «0 ^ MS CO CO A 


^ 

3 


?• 
a 


AfwitHI 


^ ^ rt ^ «-|. F^ ^ 


'X|noo|ui qq^n; 




1 


OD 


^ifiniaa 


8g|Sg523KeSSS 


'i^ftto^tni^iiin 




3 




•x^wita 


inH «-4 «^ pH p4 iF*l ^ ' 


'i^isua^ui tqifl 






'XflfUdQ 


^ss§gges??S3 i^i 


i:tMtij^)tn %^'S[rl 




la 




£%tma(i 


^ ^ r^ ,^ 1^ ^ ^ 


£%\m9tui %v{fYi 




i 


"? 

g 

^ 

* 


'i|EffQ9(X 


|S^S8SS5gS t |S! 


'i|iia^tit iii^ii 


C O O O rt w » rt ^ 40 <b 00 


i 


'it!«u^ 


C»l ■TJ ^ "W 1^ 1^ ' 


'i^isna^ai 4i|Sn 




s 


s 
s 


•X^wn^Q 


^SS^SS^S^gS] |S 


-f|i«jeci 


2SSSS§»'"S| 1" 


■y 
s 


-Iftttt^Q 


S^^^SSSiSS 1 |S 


1 




■i^iinoQ 


|SSEgSS£ggS |S 


t 


^iH>°^<^I 





Grddaiion of a Developed Photographk Image, 



311 



p4 



< 



o 

1 

c 
o 

g 








*— s 






sT 








5I« 


l-H fH f-l ,-1 




^ 












/-^s 






g«> 


oaot^»o«N-<-«^ 




t^udeo«^or^»o<^M 




3^ 


fH fH 1-^ ^ 




— <» 






,^ 








ssssss^ss 




..^ ^ pH fH . 








,^ 








gSfe2S2S5S 






,-4 »H f-« fH 




V--' 






^-^ 






2^ 


KSSSgggSSS 




5§ 




•H ^-1 c^ r^ 








^ 






2 ^• 


SS^^SSSScS 








^8 




« 










^ 


^•^ 




•s 


ss« 


gs^rssss?;: 


a 


s§ 


^ PH fH iH 


fi 


*< *^ 




^^ 








S;SS$2S3SS^ 




M SI .^ PH r-l 




•— -^ 




yN 






1^ 






M 04 i-1 i-t i-H r-i 




N-^ 




^-^ 






3S 


M r-4 pH fH fH 




w 




^-v 






Q "^ 


04-400(0000(^00) 








S 91 


Ol 04 rH r-l r-l r-l 




?»« 










^-^ 






St^ 


00«5^8oil^»o3*l 




i?s 


r-l iH r^ r-l 








^^ 






2s 


05 I-I tHiH I-I 






^-^ 




c 


< s^ 


* 


•i-i *■ 


o 








O iH 0) CO '^ »o «0 l> ^ , 

5 






(S 



5> 

0) 

i 



i> 


o 




p 

•^ 






00 




I-I 


o 






00 


2 


9» 


00 


5! 




CO 

s 




Si 


9 




3 

^ 


I"* 


f-i 


^ 







312 



Sir W. de W, Abnej. On the Variaium m 



Fig. 5 gives the results as shown in bottom line of the taUe. It 
will be seen that the slopes of the gradation of the different parts of the 
spectnim are least when near the maximum photographic effect (com- 
pare fig. 5 with fig. 2) and greatest in the red. * 










Crradation of a Developed Photographic Image. 313 

Experiments with Fixed Intensities of Rays, 

Before commenting on this curve it will be better to describe the 
next set of experiments in which the light is constant, and there is a 
change in time. 

The arrangements made were as follows: — Four slits in a card 
were made of such convenient width as (found by trial) allowed four 
different rays of the spectrum to emerge, and in front of the slits were 
cemented strips of a spectacle lens, which each gave an image of the 
prism surface of small size, but alongside one another. To prevent 
the white light which illuminated the prisms causing any error in the 
exposure, in front of each slit was placed a strip of glass of a colour 
approximately corresponding to the colour coming through it. 
Exposures were made to the four colours in the same plate and for the 
same length of time, the exposure being admitted or shut off at the 
slit of the spectroscope, and when completed the plate was given a 
graduated scale with the amyl-acetate lamp as before. The develop- 
ment of the plate was then carried out and the densities measured as 
usual. 

The curve of the amyl-acetate light was plotted first, and the places 
which corresponded to the density of the "blue" light scale was 
marked on it. It was necessary to do this, for although the electric 
arc light was steady, yet it did not remain absolutely the same in 
intensity throughout the whole of the exposiures. The places so fixed 
on the scale made by the amyl-acetate lamp by the blue exposures 
gave the points in the abscissa to which to refer the ordinates of the 
three other colour curves. These were duly set up and the curves 
drawn. Fig. 6 shows Table IX drawn diagrammatically. It was 
again found that the gradation given by the colours less refrangible 
than the Scale No. 24 were steeper than that of this No., as were also 
those of the colours more refrangible. 

The slits were then moved into new positions and the same process 
gone through. (See Tables IX, X, and XI.) When these gradation 
factors are plott^ on their appropriate scale numbers we get a curve 
convex to the base, with the lowest part lying about Scale No 24, con- 
firming the results obtained by the previous place. (See fig. 5.) There 
can be but little doubt from both of these results that the place of 
minimum gradation given by rays is close to the wave-length to which 
the salt of silver under consideration is most sensitive. 



314 Sir W. de W. Abney. On the Variaiian in 

Fio. 6. 




-/ 2 — 5 — ^ 6 nr r 9 3 

Number of eacposurm fbrAmifLiAoeCdLCe Lajnp. 
Table IX. 



Amjl- 
acetate. 




Scale numbers. 








65-4 


40-6 


31-4 


22-2 




(A 6277) 


(X5300) 


(A 4901) 


(A 4584) 


E 


D 










K 


1) 
26 


E 


D 


£ 


D 


E 


I) 


1 


47 


1 


1 


33 


1 


51 


1 


42 


2 


60 


2 


35 


2 


43 


2 


61 


2 


53 


8 


98 


8 


42 


3 


47 


3 


85 


3 


70 


4 


186 


4 


63 


4 


73 


4 


118 


4 


101 


5 


159 


5 


114 


5 


110 


5 


155 


5 


135 


6 


192 


6 


151 


6 


144 


6 


187 


6 


165 


7 


225 


7 


2U2 


7 


186 


7 


225 


7 


202 


8 


242 












* 






9 


250 
















- 



Gradation of a Developed Plwtographic Image. 



:il5 



Table X. 



Amyl- 
acetate. 



D 



1 


55 : 


2 


70 ! 


3 


04 


4 


128 1 


5 


162 


6 


198 


7 


228 


8 


240 : 


9 


250 1 

1 



Scale numbers. 




Table XI. 



Amyl- 








Scale numbers 








acetate. 










i 


47-4 


32-7 


22-8 


14-5 


'ED 


(X 5683) 


(K 4952) 


(\4602) 


(A 4364) 


1 1 


E 


D 


E 


D 


E 


D 


E 


D 


1 i 

1 75 


1 1 66 


1 


45 


1 


77 


1 


105 


2 


99 


2 108 


2 


61 


2 


113 


2 


142 


3 


123 


3 


184 


3 


83 


3 


134 


3 


163 


, -1 


147 


4 


165 


4 


110 


4 


164 


4 


191 


1 5 171 


5 


193 


5 


135 


5 


182 


5 214 


1 G 1 195 


6 


202 


6 


143 


6 


190 


223 - 


7 i 217 

















In the above tables, E is exposure and D is measured opacity in degrees of the 
annulus. 



VOL. IJCVlll. 



L 



318 Sir W, (le ^\. Abiiey. On the VariatiOH in 

Table XII. 



From table IX. 


From Tabic X. 


From Tiible XI. 




GiadMictii 


8<^ 
iiumbef-. 




number. Udtor. 


5S-4 
40a 

ai-4 

22 2 


1*^ 

I'll 

I'OO 


SSI'B 

15 
6'G 


110 
I 00 

1^2 
I '10 


47 4 

22 8 

14 '5 


l-2Ci 
1-07 

i-oo 

1 04 



Th* " QimdAtioQ fiactor " i* the alteration rpquired in tU& ftbicis«ii when ripre88«*d 
iu powers of 2, fbe aciilfi No. 22'2 having ab^obatL of an it l<?Dgtli, 



Table XIII.— ExpoBures 
to Amyl-aoetate. 



Table XIV.— Exposnres for 
Monochromatic Bays. 



yo. 


Time ia 


Beconds. 

1 


1 


2 


2 


3 


4 


4 


8 


5 


16 


6 


32 


7 


64 


8 


128 


9 


256 





Time in 


No. 


minutes and 




seconds. 


1 


5" 


2 


10" 


3 


20" 


4 


40" 


5 


1'20" 


6 


2' 40" 


7 


5' 20" 


8 


10^40" 



Experiments with Fixed Intensities of Bai/Sy and Times of Exposure varied 
by means of a Rotating Disc, 

Still one more plan, however, remained to be tried, \\z,, with a 
fixed intensity of light, but an alteration in the time of exposure by 
rotating a disc with gradually increasing apertures before the plate. 
The disc so pierced is shown in fig. 7. It will he seen that there 
are two apertures, one near the centre and another at the extreme 
outside of the radius, which include 40° only. There are thus three 
apertures of 40% and if the patch of light is uniform the readings of 
the three should be the same. All the plate was covered by a mask 
except a portion ^-inch wide which extended its whole length, so that 
successive portions might be exposed to rays of different wave-lengths 
at first. The exposed strip of plate was placed in a horizontal 
direction, i,e,, a direction at right angles to the edges of the prisms, 

id it was then found that the three readings of the 40*" apertui^ 



Gradation of a Developed Pliotographic Image, 



517 



were not the same. To ascertain the cause of this an*exposure was 
made through the slit without any disc intervening, and on develop- 

FiG. 7. 










Fio. 


8. 
















4 










/ 


7/ 












4 


^ 


wi 








/ 


/ 










.^ 


^ 


f 




73 




/ 


% 


/ 






DO 


-^ 


y^^ 


^^ 








£9 















A iO £C ^O sc 

Apertures of Sectors iu degrees. 



ieo 



ment it was found that the reduction of silver was greatest in that 
part which was illuminated by the light coming through the edge of 
the prism, and least where it passed through th<i \)»aq& oI \Xi^ ^fnsox^ 

1 ^ 



318 



Sir W. de W. Abney. On the VariaHon in 



showing that the glass of the prisms absorbed a certain proportion 
of the different rays as they passed through. It appeared probable 
that if the length of the jrinch-wide slit were placed vertically in 
the patch of light (t.f., parallel to the edges of the prism) no difference 
in absorption would be found. Such proved to be the case; the 
exposure through the slit and the patch of light without the inter- 
vening sectors gave a uniformly dense deposit, and when the sectors 
were replaced the densities given by the three 40'' e3qx>sures were the 
same. On each plate exposures were given to four different colours, 
the total exposure varying in each case according to the colour ; a 
single exposure was also given to some colour without the sector, 
and an exposure to an amyl-acetate lamp was also given. The 
following tables give the results obtained, and fig. 8 the results 
shown diagrammatically of Table XV, and the combined results are 
shown in fig. 5. 



Table XV.— Densities. 



Aperture 

of 

sectors. 


1 
Scale number. 


55*4 
(A 6277) 


40-6 
(A 5300) 


31-4 1 22-2 

A4901 I A4584 


o 

5 

10 
20 
40 
80 
i 160 


35 
42 
57 

82 
130 
178 


37 

44 

60 

80 

119 

159 


1 

45 1 45 

60 65 

85 90 

122 ! 125 

160 i 160 

197 1 195 1 



Table XVI.— Densities. 



Aperture 




Scale number. 


of 
sectors. 


39-3 
(A 5320) 


25 

(A 4675) 


■ 

15 16-6 

(A 4377) (A 4162) 


o 

5 

10 
20 
40 
80 
160 


53 

67 

89 

115 

140 

166 


75 
98 
121 
14 1 
167 
190 


i 

75 ! 53 
100 60 
125 82 
150 107 
174 133 
198 1 157 j 



Gradation of a Developed Pliotographic Image. 
Table XVII.— Densities. 



319 



Aperture of 


Scale number. 1 










sectors. 


17-6 


8-8 


-6-7 


-15-8 ! 




(X4450) (A 4100) 

1 


(\4180) 


(X8940) 


o 

5 


60 


7H 


85 


93 


10 


76 


95 


102 


119 


20 


97 


118 


127 


145 


40 


118 


142 


158 


171 


80 


140 


165 


171 


185 


160 


152 


185 


187 


192 



Table XVIII.— Densities. 



Aperture of 


Scale number. 








sectors. 


32-7 


22-8 


14-6 




(\ 4952) 


(X4602) 


(A 4364) 


c 

5 


35 


77 


45 


10 


41 


101 


57 


20 


58 


124 


75 


40 


72 


146 


99 


80 


90 


169 


122 


160 


114 


192 


147 


320 


138 


202 


171 



Table XIX. 



Scale 


Gradation 


Scale 


Gradation 


Scale 


Gradation 


number. 


factor. 


1 number. 


factor. 


number. 


factor. 


55 -4 


1-35 


1 

25 


1 
100 1 


-6-7 


119 


1 40-6 


113 


15 


1-06 I 


-15-8 


1-23 


! 31-4 


105 


6-6 


109 


82-7 


1-05 


; 22-2 


10 


17-6 


1025 


22-8 


1-00 


1 39-3 


112 


3-3 

1 


110 


14-5 


1-04 



It will 1)6 seen that these gradation factors are very closely the same 
as those obtained by the other plan of altering the time exposures, 
the intensity of the light acting remaining the same. The curve in 
these results has been pushed further into the ultra-violet than in the 
other experiments. 



320 Sir W* de W. Abnej". On ilw Vm^ii&n in 

Causes of Differmm of M^mlis in the Experimeni^^. 

We next have to consider the cause of the difference lietween the 
results obtained when the intensity of the light wa^ altered, tho time 
>>eing fixed, and these Wt two sets of resiUta, I must refer to a papier 
which appeared in the 'Proceedings' of the Koj-al Society in 1893, 
entitled " On a Failure of the Law in Photography^*' &c., more par- 
ticularly tu the Addendum ui tiuly 4ili, when it was nhuwu that UiuU|$u 
the product of time of exposure and intensity of light remained con- 
stant, yet when the intensity was diminished the photographic action 
might also be less, and that when the intensity became very small, the 
diminution was very marked. These observations were furtiher de- 
veloped in subsequent communications to the Boyal Photographic 
Society, in the same year, and it was sho¥m that when the intensity of 
the same light remained constant during a set of exposures, the time 
being altered, the gradation of the plate remained the same though the 
curves occupied very variable positions in relation to the scale of 
abscissse. Thus if withi a light of a unit intensity exposures were 
given to different parts of a plate for, say, 1, 2, 4, 8, &c., seconds, and 
the light was reduced for another set of exposures on the same plate 
to 1/100 unit, and in order to make time x intensity constant in both 
cases the exposures were prolonged to 100, 200, 400, 800, &c., seconds, on 
plotting the densities of the deposit in the manner described above, the 
two curves woidd be strictly parallel though by no means coincident. 

In the last two sets of experiments as the relative times of exposure 
are kept the same, though the intensity is small, the gradation of the 
different rays would be the same, however much the intensity was 
increased. On the other hand, where the intensity of the light is 
small (and when we say intensity, we mean the photographic intensity), 
the gradation would be steeper than would be the case if the 
intensity of the light were large. The photographic intensity of the 
light used for the red ray is less than 1/500 of the blue: hence on 
this account alone the '* gradation factor ** is larger than in the last two 
sets of experiments. This accounts for the difference between the 
gradation factors obtained by the two methods, from the red to the 
blue, and also for the approximate coincidence from the blue to the 
extreme violet when the photographic intensities of the light used are 
nearly the same. We see, then, that the gradation factors as found 
by the last two methods are those which really represent the difference 
due to the alteration in wave-lengths of the monochromatic light, and 
that the factors found by the first method are compounded between 
this alteration and that due to diminished photographic intensity. 
As before remarked, the results of the first method of experiment- 
, ing are those which apply to camera images, for they are formed by 
Bi^fferent intensities of light, and the exposure is the same for any 
w If, then, a plain surface were covered with a graduated scale 



Gradation of a Developed Photographic Image, 



321 



of greys, and a photograph taken of it through red glass, which 
practically cuts oft' all spectral rays except the red, and also through 
blue glass, the gradation of greys in the negative would be much 
more pronounced in the case of the red image than that of the blue, 
anfl we come to the conclusion that for three-colour photographic 
printing from a "red," a "green," and a "blue" negative this difference 
should be a source of difficulty, and this is certainly the case. 

AVhat scientific explanation there is of this difference in true 
gradation factor is hard to say. It almost appears that in the case 
of the blue waves acting on the atoms of the molecule of sensitive 
salt, whilst the amplitude is increased the rate of oscillation is slightly 
altered, gradually making the periodic motion of the waves of light 
out of time with the motions of the atoms ; whilst with the red rays, 
which are vastly out of synchronism with the atomic swings, the 
atoms got more nearly synchronous with them, and thus produce 
more photographic action. In my work on * The Action of Light in 
Photography,' I have given a possible explanation of the difference 
in effect caused by a feeble intensity and a great intensity of light, 
and it may be that the same kind of explanation might hold good in 
this newly foimd phase of the action of light. It appears that these 
photographic phenomena are worthy of attention from the point of 
view of molecular physics. 

It may be thought that these results might be peculiar to the salt 
of silver experimented with. A further series of experiments were 
conducted with the chloride of silver in gelatine. The maximum 
sensitiveness of these plates was found to l>e near H in the solar 
spectrum. The gradation was found to be least at this point, and 
increased when rays on each side of this point were employed to act 
on the film. In the blue near the F line, where the sensitiveness of 
the plate was very small, the gradation was excessively steep, as it 
also was in the extreme ultra-violet. 

JFave-lenf/tlis fo)' Pmrmitk Smk, 
The following table shows the wave-lengths of the scale Nos. : — 



Scale No. ! 



X. 



Scale No. 



X. 



60 
58 
56 
54 
52 
50 
48 
44 
40 
36 
32 



673 
652 
633 
615 
600 
585 
572 
548 
527 
508 
402 



28 

24 

20 

16 

12 

8 

4 



-10 

-20 



478 
464 
452 
440 
430 
420 
410 
400 
381 
364 



322 A CrydaUographical Study of certain Double Sdmodes, 



*' A Comparative Crystallographical Study of the Double Selenates 
of the Series lUMCSeO^eHsO— Salts in whieh M is Mag- 
nesium." By aT R TtTTTON, B.Sc., r.RS. Received April 29, 
— Kead May 23, 1901. 

(Abstract.) 

This memoir on the magnesium group of double selenates, in which 
S is represented by potassium, rubidium, and csBsium, is analogous to 
that which was presented to the Society in March 1900 concerning 
the zinc group. 

The conclusions derived from the study of the morphological and 
physical properties of the crystals of the three salts are generally 
similar to those arrived at from the study of the zinc group. There is 
observed a uniform progression with regard to every property in 
accordance with the order of progression of the atomic weights of the 
three alkali metals present. That is to say, the constants of the 
rubidium salt are generally intermediate between those of the 
potassium and csesium salts. 

The magnesiiun group has, however, proved particularly interesting, 
inasmuch as the progressive diminution of double refraction, according 
to the rule which has now been established for this series of double 
sulphates and selenates, leads in the case of caesium magnesium 
selenate to such close approximation of the three refractive indices 
that the crystals of this salt exhibit exceptional optical phenomena. 
This includes dispersion of the optic axes in crossed axial planes at the 
ordinary temperature, the uniaxial figure being produced for wave- 
length 466 in the blue ; and the formation of the uniaxial figure for 
every wave-length of light in tiu-n as the temperature is raised, the 
attainment of luiiaxiality for red lithium light occurring at the 
temperature of 94 \ As the life-history of the salt terminates at 100**, 
owing to the presence of water of crystallisation, this substance 
exhibits the property of simulating uniaxial properties at some 
temperature within its own life-range for every wave-length of light, 
while still retaining the general characters of monoclinic symmetry, 
including slight dispersion of the median lines. In this respect it 
resembles to a truly remarkable extent the analogous sulphate, which 
the author ha s sho\m to possess like peculiarities, but it is even more 
striking than the sulphate, as the dispersion is much larger. It is 
interesting to observe that these optical properties of caesium mag- 
nesiiun selenate could have been predicted, given the constants of the 
potassium salt and the rules of progression established for the double 
sulphate and for the zinc group of double selenates. For the double 
selenates resemhle the double sulphates so closely that in general it 



Oil the Presence of a Glycolytic Enzyvie in Miiscle, 323 

may be said that their properties are precisely parallel, the constants 
and curves being merely moved on to a slight extent by the replace- 
ment of sulphur by seleniiun without disturbing their relationships. 



" On the Presence of a Glycolytic Enzyme in Muscle." By 
Sir T. Lauder Brunton, M.D., F.E.S., and Herbert Khodes, 
M.B. Received May 7,— Bead May 23, 1901. 

It was found by Claude Bernard as well as by Ludwig and Gene- 
rich that the blood which issued from a contracting muscle contained 
less sugar than the arterial blood which entered it. This destruction 
of sugar during its passage through the muscle might no doubt be 
partially due to the action of the blood itself upon the sugar, but it is 
natural to think that it may be due to the action of some glycolytic 
ferment contained in the muscle itself. An attempt to isolate such a 
ferment or enzyme was made by one of us (Brunton) in 1873. The 
attempt was only partially successful. The method employed was that 
of von Wittich. Some fresh muscle was comminuted, thoroughly 
mixed \i4th glycerine and allowed to stand for many days. The 
glycerine extract was then filtered off. When some of this extract was 
mixed with a solution of glucose and allowed to stand for some hours 
at the temperature of the body, a distinct diminution was observed 
in the amount of glucose, while a control specimen of the glucose 
treated in the same way ^Hith a similar quantity of pure glycerine 
showed no diminution. The presence of a glycolytic substance was 
thus clearly shown. 

An attempt was made to isolate out a glycolytic enzyme from 
the glycerine extract by diluting the glycerine and mixing it with 
alcohol. A scanty white precipitate was obtained, but the precipitate 
exhibited little if any glycolytic power. Numerous experiments 
having failed to isolate the ferment, they were not published, and 
the result was only briefly noticed in a foot-note to a paper on 
Diabetes in the * British ^ledical Journal* of February 21st, 1874. 
At that time, one of us (Brunton) administered raw meat to diabetic 
patients in the hope of supplying sufficient glycolytic fei-ment to 
enable the sugar to l)e better utilised in the body, and also tiied 
the administration of glycerine extract of muscle. The success 
attending these attempts was not, however, sufficient to encourage 
the persistent use of this means of treatmenc, and the attempt to 
isolate a glycolytic ferment was abandoned for a good many years. 

The success of Buchner in separating an alcoholic ferment from yeast 
by means of great pressiu:e gave promise of possible success in 
separating a glycolytic ferment from muscle by similar mea»&^ ^\A\5r5 



324 Sir T. Lauder Bruntou and Mr. H. Ehodes. 

the kindness of Messrs. Allen and Hanbury, who allowed us the use of 
their hydraulic press, with a pressure of five tons to the square inch, 
we were enabled to lesume the research. The following was the 
method adopted : The bone and superfluous fat were removed from 
the muscidar part of a newly killed sheep. The muscle was then 
minced in a sterilised sausage machine and pounded in a mortar with 
silver sand. The silver sand was previously cleaned by means of 
hydrochloric acid and washing with water imtil all the hydrochloric 
acid had been removed. The mass was then put into a canvas bag 
and placed imder the hydraulic press. The juice was received into 
clean, stoppered bottles, the portion which was yielded on different 
pressures l>eing received into different bottles. The quantity of juice 
obtained from a leg of mutton was as follows : — 

1 750 grammes of flesh yielded approximately — 

At 0*1 ton pressure per sq. inch ... 450 c.c. of juice. 
„ 1*2 tons „ „ ... 350 c.c. „ 

„ 2-5 tons „ ,, ... 125 c.c. „ 

The method of experiment was as follows : — 5 c.c. of the muscle 
juice were placed in a flask and boiled for one minute, 5 c.c. in another 
flask remained imboiled. To each flask 50 c.c. of a 1 per cent, diabetic 
sugar solution and 5 c.c. of a 1 per cent, solution of lactic acid, with a 
fragment (about 0*25 gramme) of thymol were added. Both vessels 
were incubated at 37" C. for 24 or 48 hours. After the incubation was 
finished the sugar was estimated in both flasks by titration with 
Fehling's solution, after precipitation of the albiunin by boiling an«l 
neutralisation if required. Six experiments were done with concordant 
results, and we have only given the result of one as being typical. 

Sugar as estimated by reduction of Fehling fluid — 

1st sample A (boiled juice) 48 hrs.' incubation 0*57 per cent, dextrose 
2nd „ B (unboiled juice) „ „ 0*2 „ „ 

The destruction of sugar in the flask containing unboiled sugar 
seemed to be almost certainly due to some glycolytic enzyme, as 
the contents of the flask remained quite clear at the time of experi- 
ment. Later on, however, the contents of the unlK)iled flask became 
turbid, and after four days a definite growth of fungi was obtained. 
We next attempted to render the muscle juice sterile by a Pasteur- 
Chamberland filter. The sugar solution was sterilised by boiling, and 
all the flasks and other vessels used in these experiments by heating in 
an autoclave. The muscle juice after filtration was completely sterile, 
as was shown by the fact that it was kept in a bottle plugged with 
sterilised wool for many weeks without any bacterial growth exhibiting 
itself. The glycolytic power of this sterilised muscle juice was tested 
in the following manner : 5 c.c. of the sterilised juice w^is placed in 



0)1 tlie Presence of a Glycolytic Enzynie in Mtiscle, 325 

each of two flasks. In one of them the juice was boileil so as to 
destroy any glycolytic ferment it might contain. Into each flask we 
then placed 30 c.c. of a 2 per cent, sterile solution of diabetic sugar. 
They were incubated for forty-eight hours. The amoimt of sugar 
in each flask was then ascertained by titration with Fehling's solution 
in the same way as before, and the result obtained was 1*5 per cent, 
of diabetic sugar in the flask containing boiled meat juice, and only 
•0-75 per cent, in the flask containing imboiled juice. A very distinct 
glycolytic action is thus shown by this experiment, which was repeated 
three times with identical results. 

A number of experiments were now made to isolate an enzyme by 
dialysis through membranes consisting of sausage skin or parchment. 
In the first series a distinct glycolytic action was observed, but this 
was probably due to bacterial action, as the media became turbid, and 
in a subsequent series made with aseptic precautions no glycolytic 
power was observed in the dialysate, although a flocculent precipitate 
resulted on the addition of absolute alcohol. 

An attempt was made in another series of experiments to isolate the 
glycolytic ferment of muscle itself by precipitation. These were not 
successful. Fresh juice was mixed with four times its volume of 
absolute alcohol, the precipitate was collected, dried and pulverised. 
It was then extracted with glycerine, but this extract had little or no 
glycolytic power. It gave a white flocculent precipitate with absolute 
alcohol, which was soluble in saline solution, but which was quite with- 
out any glycolytic action whatever. The action of muscle juice was 
also tested on neutral diabetic urine and on a neutral solution of com- 
mercial dextrose. The results were as follows : — 

Flask C contained 2 c.c. boiled muscle juice and 10 c.c. neutral 

diabetic urine. 
„ D „ 2 c.c. unboiled muscle juice and 10 c.c. neutral 

diabetic urine. 

After 50 hours' incubation at 37° C. 
C contained 1*25 per cent, of dextrose. 
D ,, 0'75 „ ,, „ 

Flask E contained 2 c.c. boiled muscle juice, 10 c.c. neutral dial)etic 
urine and 1 c.c. of a 1 per cent, solution of 
lactic acid. 
„ F „ 2 c.c. unboiled juice, urine, and lactic acid as E. 

Again after incubation 

E contained 2*5 per cent, dextrose. 
F „ 0-5 

Flask G contained 2 c.c. boiled muscle juice, 10 c.c. neutral solution 
of 0*5 per cent, commercial dextTos.^. 



326 



Annual Meeting for tJis Elediim o/FeOows. 



Flask H contained 2 c.c. unboiled muscle juice, tihe rest as O after 
incubation. 
„ O „ 0*37 per cent, dextrose. 
„ H gave no reduction with Fehling's solution. 

The experiments that we have described prove, we think, that 
muscle certainly contains a glycolytic enzyme, though it is <rf such a 
delicate nature that we have not been able to isolate it without 
destroying its power. 



Jwu 6, 1901. 

Annual Meeting for the Election of Fellows. 

Sir \MLLIAM HUGGINS, K.C.B., D.C.L., President, in the Chair. 

The Statutes relating to the Election of Fellows having been read, Sir 
George King and Professor Herbert McLeod were, with the consent 
of the Society, nominated Scrutators, to assist the Secretaries in the 
examination of the balloting lists. 

The votes of the Fellows present were collected, and the following 
Candidates were declared didy elected into the Society : — 



Alcock, Alfred William, M.B. 
Dyson, Frank Watson, M.A. 
Evans, Arthur John, M.A. 
Gregory, John Walter, D.Sc. 
Jackson, Henry Bradwardiiie, 

Capt. R.N. 
Macdonald, Hector Munro, M.A. 
Mansergh, James, M.Inst.C.E. 
Martin, Charles James, M.B. 



Ross, Ronald, Major (I.M.S., re- 
tired). 
Schlich, William, CLE. 
j Smithells, Arthur, B.Sc. 
Thomas, Michael KOldfield, F.Z.S. 
Watson, William, B.Sc. 
Whetham, William C. Dampier, 

M.A. 
Woodward, Arthur Smith, F.G.S. 



Thanks were given to the Scrutators. 



Vibrations of Rifle Barrels. 327 



Jtnie 6, 1901. 

A List of the Presents received was laid on the table, and thanks 
ordered for them. 

The following Papers were read : — 

I. ** On the Electric Response of Inorganic Substances. Preliminary 
Notice." By Professor J. C. BoSE. Communicated by Sir 
M. Foster, Sec. R.S. 

II. "On Skin Currents. Part I.— The Frog's Skin." By Dr. 
A. D. Waller, F.R.S. 

III. "Vibrations of Rifle Barrels." By A. Mallock. Communi- 

cated by Lord Rayleigh, F.R.S. 

IV. "The Measurement of Magnetic Hysteresis." By G. F. C. 

Searle and T. G. Bedford. Commimicated by Professor 
J. J. Thomson, F.R.S. 

V. "A Conjugating * Yeast.'" By B. T. P. Barker. Communi- 
cated by Professor Marshall Ward, F.R.S. 

VI. " Thermal Adjustment and Respiratory Exchange in Mono- 

tremes and Marsupials: a Study in the Development of 

Homo-thermism." By Professor C. J. Martin. Communi- 
cated by E. H. Starllxg, F.R.S. 

VII. " On the Elastic Equilibrium of Circular Cylinders under certain 
Practical Systems of Load." By L. N. G. FiLON. Commu- 
nicated by Professor Ewing, F.R.S. 

VIII. " The Measurement of Ionic Velocities in Aqueous Solution, and 
the Existence of Complex Ions." By B. D. Steele. Com- 
municated by Professor Ramsay, F.R.S. 



" Vibrations of Rifle Barrels."* By A. Mallock. Communicated 
by Lord Rayleigh, F.R.S. Received May 2, — Read June 6, 
190L 

It has long been known that a shot fired from a rifle does not in 
general start from the muzzle in the direction occupied by the axis of 
the barrel at the first moment of ignition of the charge. 

* The greater part of the notes from which this paper is drawn were made in 
1898, but since that time the interesting experiments of Messrs. Cranz and Koch, 
of Stuttgart, on the same subject have been publish ed, and I hare looked through 
my notes again and put them in their present form, as it maj be of some interest 
to compare results obtained in such different ways. 



S28 Mr. A. Malloek. 

The late W. E. Metford wgs, I believe, the first to point out the 
origin of this deviation, showing by experiment that it was due to the 
unsymmetrical position which the mass of the stock held as regards 
the barrel ; and, further, that if the initial direction of the shot passed 
below the apparent direction of aim when the rifle was held in the 
ordinary position, the initial direction would be high if the rifle were 
aimed upside down, and to the right or left if the plane of the stock 
were horizontal and the stock itself to the left or right of the 
barrel. 

He showed, in fact, that the initial direction of a shot lay on a cone, 
whose axis was the axis of the barrel at the instant before the ignition 
of the powder, and in a plane containing the axis of the barrel and the 
centre of gravity of the rifle, and he rightly attributed the deviation of 
the shot to the bending couple acting on the barrel, due to the direc- 
tion of the force causing the recoil not passing through the centre of 
gravity of the rifle. 

The object of this paper is to examine this problem of " flip " or 
" jump," as it is called, from a mathematical point of view, and to show 
what effect may be expected from given variations either in the length 
of the barrel, the nature of its attachment to the stock, or the nature 
of the explosive employed. 

The investigation is not merely a matter of cuiiosity, but has an 
important bearing on the accuracy of rifle shooting, and tmtil some 
method is introduced, not of avoiding " jump," but of suitably regu- 
lating its variation with the variation of explosive force, I think no 
great advance will be made on the precision already attained in modem 
rifles. 

This precision is already considerable, and, roughly speaking, any 
good modern rifle will shoot with a probable deviation of considerably 
less than 2' from the intended path. WTien the results indicated in 
the coiu^e of this paper are considered, it seems wonderful that such 
accuracy should be possible, and it speaks well for the quality and 
imiformity of the ammunition that such good shooting should be 
common. 

The problem of " jump " may be stated mathematically thus : — " An 
elastic tube, to which a mass is imsymmetrically attached, is subjected 
for a given time to a couple of arbitrary magnitude. Determine the 
subsequent motion." To solve this problem we must consider the tube 
and its attached mass as forming a single system, and examine what 
are the natiu'al modes of vibration of this system, and what their 
natural periods. The arbitrary couple must be expressed in an 
harmonic series as a function of time, and the forced vibration which 
each term of this series will evoke in the system calculated. 

To represent the initial conditions (namely, that at the moment 
before the explosion the barrel is at rest and unrestrained), such free 



Vibrations of Rijlc BurreU. 



!29 



vibrations of the system must be supposed to exist as, in combination 
with the forced \'ibration, will satisfy these conditions. The subse- 
quent motion will then be determined by taking the sum of the forced 
and free vibrations as long as the arbitrary couple acts, and when this 
has ceased to act, the siun of the free vibrations only. 

If the system could be represented by a uniform rod, the solution 
might at once be expressed in symbols, since the theory of the trans- 
verse \dbrations of rods and tubes is well known. When we come, 
however, to a "system" like a rifle, although in many respects its 
behaN'iour may be compared with that of a uniform elastic rod of 
" equivalent length," the ratio between the periods of the vibrations of 
its various modes are altered, and recourse must be had to experiment 
to determine both the natural periods and the position of the nodes. 

As far, however, as the rifle can be considered as being represented 
by an equivalent rod, it must be looked upon as being free at both 
ends at the moment of firing, because the motion communicated to the 
rifle is so small at the time the shot leaves the muzzle, that the con- 
straint which hands and shoulders can impose on it is negligible com- 
pared to the acceleration forces called into play by the explosion. 

This l>eing so, the slowest vibration of which the system is capable 
is that with two nodes. The next in order of rapidity will have three 
nodes, and so on, as shown in the figures 1, 2, 3. 

Fio. 1.— Mode T. 




Fio. 2.— Mode TI. 




r y I Ll 



Fig. 3.— Mode III. 



n: 



d. 



« 



i^ 



f ^.-^xEOTIlDn^ 



C.Q, 



330 



ISlr. A. Malloek. 



The fignire assumed by the muzzle enxl of the hand ^vill )>e nearly 
exactly the same in emh mode as the figure assumed in the coiTe* 
spending mode by an uniform rod whose length k surh as to make tJie ; 
distance of the node from its free end equal to the distraiice from the ' 
node to the miiz/Je of the rifle. 

The couple which acts on the l>arrel during the explofiion is measured , 
by the rate at which the shot is acceleratedj the distance of the axis of 
the barrel from the centre of gravity of the rifle. The effect of a I 
givoD couple ill causing a partioular mode of vibration in the b&irel — ' 
depends on its point of application with reference to the nodes of the 
system as well as on its magnitude. 



Fig. 4. 




QS. 



PR 



« 5fQQ. rn. = ypQ « Q.T - 5fQp. 

CHTKD is the curve into which CD is bent by F acting at P. 
CLTMD is that part of the deformation which belongs to the mode of vibration 
which has nodes at C and D. 



If in fig. 4, C and D are two adjacent nodes belonging to some 
particular mode of vibration, it is evident that a couple applied midway 
between C and D would not cause any displacement of the system in 
this mode. 

If a is the distance between the nodes C D and a couple pd at point 
P distant x from c, there will be 

(1) A downward force at C = pdi2x with an equal upward force at P, 
and 

pd 



(2) An upward force at D 
at P. 



2 {a - x) 



with an equal downward force 



On the whole, therefore, there is at P an upward force acting 



2 \x a- xj' 



or 



^ _pd-l a- 2x '. 
2 \:r{a-.c)j 



Suppose ^QQ = cF to be the displacement which the force F would 
cause if acting at the point Q, midw^ay between C and D. It is 
known that if a force F acting at Q causes a displacement y^ at P, the 
same force acting at P will cause a displacement ^pQ at Q, that is 



ypQ = y^v 



• This theorem is due to Lord Rayleigh. 



Vibrations of Rifle Barrels. 331 

Approximately, the equation to the curve between the nodes C and D 
for the mode of vibration which has these nodes may be taken as a 
simple harmonic function of x 

or y = Cgg sin 27r - ; 

(% 

hence the displacement at P due to F acting at Q, and the displacement 
at Q due to F acting at P, are each equal to 

CF sin 2ir t , 

a 

or y^^=c^— .sin2ir- (1). 

2 x{a-z) a 

In a rifle the point of application of the couple is settled by the 
nature of the connection between the stock and the barrel, and it is a 
matter of great difficulty to make certain how the strains are dis- 
tributed. The actual maximum pressure in the barrel which is spoken 
of as " chamber pressure " is known for various small arms and various 
explosives with considerable accuracy; but the curve of pressiu'e in 
terms of the travel of the shot along the barrel is much more difficult 
to ascertain. In this paper, therefore, I shall consider several types of 
such curves in order to show what effects are to be looked for as the 
pressure curve changes its character. 

The condition fulfilled in each of the pressure curves considered is 
that each must give the same muzzle velocity to the shot by acting on 
it through the length of the barrel, and in the numerical results given 
the velocity and weight of the projectile are taken as 2000 feet per 
second and 215 grains respectively, with an effective length of barrel of 
2-3 feet, these being nearly the velocity, weight, and length of barrel 
used in the Lee-Enfield rifle. 

The simplest case of all ( and the f ui-thest removed from tnith) is 
that of a uniform pressure acting on the base of the shot throughout 
the length of the barrel. 

Here we have, if po is the acceleration, Vjn the muzzle velocity, S the 
time taken by the shot in reaching the muzzle, and / the length of the 
barrel, 

Vm =i>o« (2), 

^=i>oy (3), 

Po-'i W^ 

« = ?^ (5). 



m 



VOL. LXVIII. ^ k 



332 Mr. A. MaUock. 

Putting V = 2000 is,, and I « 2-8 ft, 

we have po = 860,000 f.8.8., t « 0-0023 sees. 

An acceleration of 860,000 is about 27,000^, so that a uniform force 
of 27,000 times its own weight, or 835 lbs., would give the 215-grain 
shot its observed velocity in the actual length of the barrel. 

With a uniform force, the pressure curve in terms of space is the 
same, of course, as if expressed in terms of time ; but for any other 
case we must, for the purpose of this paper, express the pressure curve 
(which experiment would give in terms of the distance travelled by 
the shot in the barrel) in terms of time. 

The pressure at time t being p^ we have 

dv , dv dv ds dv i •• j 

.-. t.= J{2lpds) (6); 

and / = f_ -f*—^ (7). 

If we take the case of the pressure decreasing uniformly with the 
travel of the shot, it is easy to show by (5) and (6) (although the 
analogy with the force acting on a pendulum or spring at once suggests 
it), that the velocity and position of the shot are : — 

.. = i(l-cos<y^7o) (8), 

v = y/^aint^^ (9), 

Po = ^-f (10), 

^ = lf (»)• 

With the before-mentioned values for /, v, and w, ;?o = 1'174: x 
10* f.s.s. and K = 0-00171 second. 

One more case by way of example will suffice. Let the pressure 
decrease uniformly with the time so that 

p^p,(l-^j (12). 

From this we get 

» =i^^-^o^ (IS), 

'=p4{^-§-t) <!*)» 



Vibrations of Rifle Barrels, 333 

and the relation between p and 5 is 

,^ '(2-5^ + 44-4) (15). 

From (13) (14), using the above values for v„ and /, 

Po = 2-32 X 10*^ f.8.8. I = 0-00173 sec. 

The three cases are illustrated in diagrams 5, 6, 7, in which the 
various curves show the pressure, velocity, and time elapsed since the 
beginning of the motion during the passage of the shot through the 
barrel. 

Diagrams 8, 9, 10 show the pressure in terms of time, and it is 
these curves which have to be represented by a harmonic series. 

In order to avoid having a constant term at the beginning of the 
series, the fundamental t is taken equal to 2C 

Then by the ordinary rules for finding the coefficient of a Fourier 
series, the succession of " battlements " which form the pressure curve 
in case 1 (uniform acceleration), we find 

i> = Po-i sin27r- + o8in3 (2ir- l + ^si" 5 27r - +i&c. > (16). 

TT [_ Tj O \ fj/ h J 

In case 2, where the pressure curve is a succession of half-lengths of 
a simple harmonic curve, the general coefficient of the 7ith term is 

2 471 
^%4;t2-l' 
and the series is 

,,=p„£{|sin2.^i + ^sin2(2.|) + &c.} (17). 

The series for case (3), where p = po(l- —7), is 

y> = ;?0^sin2 7r^+^sin2(27r^-j + ^sin3/'27rM + &^^ (18). 

The coefficients in series 17 and 18 soon become sensibly equal in the 
corresponding higher terms of each. 

In the cases just considered, except the first, it is assumed that the 
pressure at the muzzle is zero, which of course is not true, but the 
existence of a terminal pressure can be readily represented by adding 
a series of the form of (16) of suitable magnitude. The effect of this is 
to increase the relative importaj;ice of the first and all the odd terms. 

We must now examine the forced vibrations which each term of tbe 
series expressing the accelerating pressure wowld ^et u^ m xJtvjsi tAr^ 



334 



Mr. A. MaUodk. 



«* 



JV 












0/^^ 


^ 


!7A 
















• * 

• £ 














































































































































































^ 








A 


»- i' 


HAf*7 


N 












DiA^ 


fmi 


f^. 
















\ 


































N 


V 






























N 


K 
































N 
































S 


s. 






























S 


\, 
































N 


iii_ 
































N 


s 





























I 


1 






>m 


l£ ^ 






















* 












































Kfȣ-3 
































" /a 


\ 












Di^ 


^/uJ 


W7, 














\ 






























\ 
































\ 






























\ 
































\ 
































\ 


V 






























N 


X 


































\ 


"X^ 
































- 


"^ 


































<^ 












°l 


7 








4 


f 








J 


» 








/« 


■» i 



Vibrations of Rifle Barrels, 



335 



AoceUmCfon 



to 
















o^ 


fmji 


i«. 


















«*.« 
























^ 












































































4 , 






































£ 












' 




























1 








-oi 


»/ 








■« 


t£ 


4 

* 






'{K 


^St 


'CO/* 


fs. 


tefio'T 


^ 


^ 




















1 
1 














y*^ 






N, 


\. 
















1 






















\ 


^ 














i 














mB 










\ 


s 




J 


^n%j 


73. 




L 




"-- 







— 




l(fi.6 












\ 






































\ 
























d 














\ 


V 






















^ 
















\ 






















£ 


















\ 































-O 


u 






t, 


•O 


Iff 








1 "^ 


isS 


cty^ 


h. 






















\ 






































- ' 


















Xfiit^ 


V 




















\ 


"; 














£ 


N 


k 




















\ 
















\ 






















\ 
















\ 






















S. 
















N. 


V 








D/A 


fm 


mi6 










X 
















\^ 


^ 






















;-*,, 


.^ 












\ 









































\ 




































y 


\ 




































\ 


V 




































\ 






































\ 




























'Oi 


It 






t' 


k! 


V 








*oi 


aJSi 


cckr^ 


^. 



supposing that the harmonic couple it represents continued to act. If 
Ti, T2 ... Tot are the natural periods of the various modes in which 
the rifle can vibrate, and d the distance of the ceuU^ oi ^^nSx.-^ Vwso^ 



336 Mr. A. MaUock. 

the axis of the barrel, the forced oscillation which the nth term in the 
series will evoke in the mth mode of the rifle will be, when expressed 
as the angle through which some particular part of the system bends 
during the oscillation, is 

e = e„pdAnj-lj^sm2niri (19). 

In this expression Sf^ia the angle at the place of observation which the 
unit couple would cause if acting to produce a displacement of the 
system in the mth mode (the values of 0m can be found approximately 
by statical experiments on bending). 

An is the numerical coefficient of the nth term of the harmonic 
series, and 

3«. = ^ or ^ (20). 

r» nil 

To represent the initial conditions, which are that the moment 
before the explosion the barrel is at rest and imstrained, it suffices to 
suppose the co-existence of free oscillations of the system, with phases 
and amplitudes such as to make the velocity and displacement zero 
when / = 0. If a and b are the amplitudes of the forced and free 
vibrations respectively, we have 

<'8in27r- + ftsin27r^ =0 (21), 

n In 

^ir t 27r t 
and ^flcos27r — + ,p-6cos27r— =0 (22), 

whence ^nm = -- (23), 

hence the free vibration, which at / = leaves the system at rest, so 
far as the oscillation excited by the nth term in the mXh mode is con- 
cerned, has ([nm times the amplitude of the corresponding forced 
vibration.* 

It is convenient in the complete expression for displacement to refer 
to the natiu*al periods of the system, which are constant, rather than 
to the periods contained in the pressure curve. So, substituting for t^ 
its value Tm/qntm we have for the angular displacement of the system 
at that time after the explosion (i.e., for the simi of the forced and free 
vibrations at that time due to the term and mode under consideration) 



* For the purposes of this paper it is not necessary to consider the grmdosl 
extinction of the free Tibrations, for the nnSnber of periods inrolved is so smill, 
even for the highest component taken into account, that extinction will not mate- 

%lljr mffect the amplitude. 



VihrcUiom of jRlftn Barrels, 337 

^nm = 0,„ptlAn- — Kr»n sin 2^)-- - sin ^n»i.2ir _- ) ... (24). 

Diagram 11 shows the curves represented by the function 
q_^nj>_^nq^ from <^ = to </> = 2ir and 7 = 06 to ry = 4. 

When (2=1 this expression takes the form of a . which, evafuated 
in the usual way, gives 

<t> cos </) - sin </) 
2 

I will now apply the above results to examine the form of the Lee- 
Enfield rifle at the moment the shot leaves the barrel, assuming that 
the pressure developed during the explosion is that shown in fig. 10, 
taking into consideration the first three terms of the harmonic series 
for that curve and the first three modes of vibration of the rifle. 

For this rifle it was found by experiment* that a couple of 1 foot-lb. 
acting at the nodes caused at the muzzle the following deflections : — 

Model Bi = ri3 

Mode II e., = 0'-765 

Modem 63 = 0-565 

In the authorised * Text-book for Military Small Arms ' the initial 
pressure in the chamber of the Lee-Enfield is given as 16 tons per 
square-inch. 

The area of the base of the shot is 0*0725 square-inch, so that the 
initial pressure on the shot is 1*09 tons or 2450 lbs. Since the weight 
of the shot itself is 215 grs., the force acting on it is ^V/ ^ 2450, 
nearly 80,000 times its own weight. Multiplying this by g, the 
acceleration which the shot would undergo in the absence of friction 
in the barrel is 2,560,000 feet per second per second. 

In case 3 (14) the initial pressure was found to be 2,320,000 feet per 
second per second, so that, allowing for the force required to press the 
shot into the rifling and the friction in the barrel, it seems probable 
that the pressure ciu*ve of case 3 represents with some degree of 
approximation the actual acceleration which the shot experiences. 

* It would occupy too much space to describe these experiments in detail. They 
were made by loads suitably placed on tlie rifle, and the deflections caused by them 
were measured by optical means. The deflections so found were reduced to what 
they would haye been had the action of the couples been concentrated at the nodes. 
In virtue of the approximate straightness of the free end of a vibrating rod, the 
angular deflection at the muzzle was taken as equal to the angular deflection at the 
nearest node. Hence the defleciioni above given are rather less than the trut 
values. 



338 



Mr. A. MaUock. 



The centre of gravity of the rifle is just an inoh below the am of 
the barrel, and, taking the acceleratiye pressure on the shot as 
2250 lbs., the bending couple at the first instant is 187 ft.-lbs. 






*' - 5' 



^-s- 



Also 

Thus 
jPorfAi = 118ft..lb8., j»arfA2 = 69 ft.4bs., p^AM = 40ft.-lbs., 



^^P(^Ai = 133' 
Bxp^A^ = 66'-5 
^ijMAs = 46' 



Table I. 
e^Ai^ 90'-5 
e^A^ » 45' 
e^Kz = 30' 



e^^Ax « 66'-6 
tf^As - 33'-3 
^jMAs = 22'-2 



These are the angular displacements which the muzzle would 
undergo if in each case it experienced the full statical effect of coufde 
corresponding to the first, second, and third term of the series repre- 
senting the explosion curve acting so as to deform the system in the 
first, second, or third mode. 

Owing, howeverj to the position of the point of application of the 
couples with reference to the nodes of the various modes (see I, and 
figs. 2 and 3), it appears that for the first mode the couple will cause 
0*88 of its full effect, as for this mode the node Ni" coincides nearly 
with the point of application of the couple. The nodes N2' and N*" 
of the second mode fall at such a distance from P as to reduce the 
effect of the couples to about 0*35 of the above value. And the reduc- 
tion is about 0'6 for displacements in the third mode. 

The following table is an approximation to the actual values of — 

Table II. 



It. 


1. 


2. 


3. 


1 


117' 


31' -5 


89' 


2 


69' -6 


16' -8 


20' 


3 


80'-5 


10' -6 


18' -2 



To determine the periods Ti, To, Ts, namely the natural periods of 

the rifie in the first, second, and third modes, experiments were made 

by tapping the barrel so as to excite the modes in question, and deter- 

lining the notes emitted by comparison with tuning forks. The 



Vibrations of RijU Barrels, 



339 



positions of the nodes were found by noting the position of the points 
of support which did not damp the vibrations in each mode examined. 
The results were as follows -. — 



Table III. 



Model 


! 
Frequency. Period. 

j 


Distance of 
nearest node 
from muxzle. 


Pep sec. sec. 
66 -015 


in. 

12-5 

8-6 

6-5 


Model! 


172 ' 00576 
395 -00258 


Mode III 





In case 3, again, the value found for 8 was 0*00173 second, hence 
for the assumed ammunition ^i = 0*00346 second. 
We can now construct a table of the value of qnm- 

Table IV. 
Values of qnm for m = 1 to m = 3, n = 1 to n = 3. 



h 


T,. 


Tj. T3. 


4-8 

8-6 

17-2 


1-64 
3-28 
4-92 


0-72 
1-44 
2-94 



The abscissa on Diagram 11, which corresponds to the time C 
will be 

For Mode I 27r-|. = 42^-5. 

Ti 

„ Mode II 2ir^ = lir 

„ Modem 27rJ- = 250\ 

Ts 

If then Diagram 1 1 had curves for all values on it, we should, in order 
to determine the deflection (due to vibration evoked in the with mode by 
the nth term of the harmonic series) of the muzzle as the shot leaves it, 
merely have to take the ordinate of the curve for which q = j„,„ at the 

AT 

abscissa 2ir -f- , and multiply this ordinate by OmpdAn as given in 

I?/i 
Table I, but the diagram, to avoid confusion, has shown on it only 
curves relating to a few values of q. 

Using, however, the values of qnm given in Table IV, and computing 
Onm for these values, by 24 it is found that 



340 



Mr. A. Mallock. 
Table V. 



011 - 19'*5 up. : 9|s a 28''5 down. 



*2i - *''7 «P- ! *« - 4'-8 down. 



«„ = l'-55 up. fli- » 2'05 down. 



01, . eo' up. 



9«a - 25' down. 



Om - 4*'9 down. 



DiAOBAX 11. 




1 




j 1 




.-^-^ -^ — -^ 


s 


'"^ \ \ ■ ^ ~ 




•tC ■• ^v ^. ^ 




*Cv >, X-*' 


-A J V 


•^3fl^» S^^ V 


J!^^^ 


.^^5j: 5 ^t L. 


^ ^Z^ - 


tAj, Owfri ^ 


M/7k ^ 




1 1 jf/f/ / L^iT^ 


1 ""^\| \t \ \ 




[\\\ Y^ \ t ^ 


* i^i^d: s 


\ V ^' \ V 




\ l\ > ^L V \ 


1 J \/WJ^^ «i^a„4 


ffaL^fAL^^ 'V 




S Tl^x 3 c 


J " /w^n ' '^ 


' \ ^\ 1 V 


J>5^*^"^i.kii A 




^ -^2^ T — ^- \ 


\" ^ \ \ \ / 




ii'\' \] \ ^ \ { \ 


O—'ir 41 36 ii~' liio »i> i^ f^nl 


i^y^^^^c UoiO^ fM A^,.ik? dr 3 a 




N tL 3r^ u \ ' ,>K?^ \ / 




I T^^ti x^ w 




it t Jul ""S i 




. T T TV y J Tv 




N \ lu I / 1 




v\ I vL I ' / V 




\\ L^_yL x. J, u*.\ 




^'^^'V y\ \ p' ^^} 




{ \ \ 1 J 




: 5 . It 2 




,±4:43»A 13^1 


IZ '5" ^"SI3*[S 


^2 ^ tin JUJ3 


^.d — .. 1 


> \ X , ; 




31 t ut 




I ^ ^ 








Vl 




^ K x A.' 




- - Vi if^" 








V ft^ ^0 




1 *^5— jK i i 




^ ^ \\ t \ ^ 




1 iK A 




jsjU ylt 




Ty -"^ \ 




^ }\v. 




"IpfoOai w^ 


^J-J — L LU .i.l .1 1 [ 1 1 i 1 1 1 


) vS^ 



Vibrations of Rifle BairreU, 



341 



Hence, adding these results, we find for the total upward deflection of 
^5'-85, a downward deflection of 65''25, or finally, a resultant of 20' '6, 
as the angle which the instantaneous axis makes in an upward direc- 
tion with the unstrained axis of the barrel, at the moment of the shot 
leaving the muzzle. 

The course of the shot (lifters from instantaneous axis of the barrel 
by an amount depending on the ratio of the transverse linear velocity 
of the muzzle (due to the vibration) to the muzzle velocity of the shot. 
The transverse velocity v' of the muzzle consequent on the ?ith term 
vibration in the 7;ith mode, can be obtained by differentiating 6nm with 
respect to /, and multiplying by R^ (the distance of the nearest node 
of the mth mode from the muzzle). We then find the ratio r'jv 



mode from the muzzle). We then find the ratio r jv 
= ^^f^"(co8 2. ?-.-cos2.,„„^) 



(25).* 



Computing from this a table of corrections of angle corresponding to 
Table V representing the alterations of the values of the angles in 
Table V depending on the vertical linear s|)eed of the barrel, we have 
approximately 

Table VI. 



1. 

2. 
3. 



4'-6 up. 

0'-35 

0'-21 



II. 



2'*5 down. 

O'O 

0'-8 



III. 



6'0 up. 

O'O 

O'O 



or on the whole 6'-9 of upward inclination must be added to the 20'-6 
found from Table V, so that the flight of shot lies 27' nearly above the 
direction of the unstrained axis. 

The actual jump found by experiment for the Lee-Enfield nfle is, I 
Ijelieve, nearly about this amount, but from the uncertainty of the 
positions found for the nodes in the neighbourhood of the breech, and 
the small number of terms (imputed, as well as the doubtful approxi- 
mation to the pressure curve, no great accuracy could be expected. 
The example is useful, however, and is introduced to show that the 
jump depends on the difference l)etween comparatively large quantities, 
many of which are sure to be varying rapidly with qnm- 

The variations of Qnm may be caused either by the variation of Tm 
or /„. For each individual rifle Tm of course is constant, depending as 

• It may be noticed that in (24) ond (26) sin Zvq^m Jf must - 0, and 

C ^^ 

x«)9 2Tqim ^ = ±1. 



342 Mr. A. MaUock. 

it does only on the elasticity and mass of the weapon, bat in and A» 
depend on the rapidity and rate of the explodon. 

Suppose that in place of assumed explodve a slower burning explodve 
were used, with a charge sufScient to give the same muEsle velocity. 
This would cause an increase in C and in ; that is, ^mm would be dimin- 
ished, and, owing to the greater terminal pressure (see (15) d $eq,) all 
the values of An forn odd would be increased in relative importance 
compared with those for n even. The result in the case of a small 
variation of this kind in the Lee-Enfield would be an increased upward 
jump. 

A lower muzzle velocity would also correspond to an increase of C, 
and would give an increased upward jump in this rifle, and at some 
particular range it should be found that the variation of jump and 
variation of initial velocity compensate one another, and that for 
moderate variations of charge the sighting at this range does not 
require alteration. 

The natural periods* of the rifle may be altered either by adding 
mass, or shortening the barrel. In the first case t will remain un- 
altered, and qnm will increase ; thus the tendency of a small mass added 
near the muzzle will be to make the rifle shoot low. 

If the barrel is shortened both T,,, and C are diminished, but the 
alteration in T^ (which depends on the square of length of the 
equivalent rod) is much more important than the alteration in £' ; 
hence a small shortening of the barrel may be expected to cause a 
considerable diminution in qnm and a corresponding increase in 
upward jump. 

The most important factors in these changes (as regards the Lee- 
Enfield) are (/i.o and </i.3, that is the eflect of the first term of the 
harmonic expansion of the explosion ciurve in exciting the 2nd and 
3rd mode vibration of the rifle. 

If ammunition could be made absolutely uniform in its action^ 
"jump" would be of comparatively small importance, but the 
± 40 feet per second by which the initial velocity of the service 
bullet varies may, by altering the factors on which " jump " depends, 
exaggerate with some classes of rifles, and diminish with others, the 
variation of the trajectory due to the effect of gravity and the altered 
initial velocity. 

Suppose a rifle to be aimed and shot from P^ fig. 12, so as to hit 
the centre of a target T^ at range R, when the initial velocity is V. 
What will be the effect on the aim of a variation of the initial 
velocity 1 

Let a be the angle of elevation of the rifle and j8 the angle of 
descent of the bullet at Ti. Let F be the place in the trajectory of 
the shot (whose initial velocity is V) where the velocity has fallen to 
y - V, If a shot is fired from Po with the same sighting as was used 



Vih^atioiis of Rifle Bairels, 



34» 



at Pj and with the initial velocity V - r, the trajectory of this shot will 
always be a constant distance P1P2 below the trajectory through Pj, 
and will therefore strike the target T, at this distance below the 
centre. If a second target, To, is placed at a distance PjPa (= a) 
behind Ti so that PiTi = PoTo = R, the second target will be struck 



Fio. 12. 




a/? below the hit in the first target ; hence since PiPg = aa, the error 
due to the variation of initial velocity is a (a + j8). fi may be found 
from the range tables of any rifle by the relation 

Applying this to the Lee-Enfield, the following table shows the 
errors due to a variation of 40 feet per second in the initial velocity, 
on the assumption that the direction of the shot is not affected by 

"jump." 

Table VII. 

a = 54 feet = distance from muzzle at which the speed has fallen 
40 feet per second. 



Range in 
jards. 


a. 


3. 


rt(a + )B). 


= ^(..«. 


1 


i 




feet. 




100 


1 4' 


48' 


0-141 


l'-6 


500 


1 31' 


43' 


1-17 


2'16 


1000 


: 88' 


144' 


8-8 


4'35 


1500 


177' 


320' 


7-8 


6'0 


' 2000 


305' 


570' 


13-8 


7'-8 


2500 


477' 


980' 


230 


10'5 



These errors are comparable with, but, especially at the longer 
raiiges, greater than what the best shots are liable to in practice, so 
that with this particular rifle the compensating action of the variation 
of " jump " is a distinct advantage.* 

For some time I was under the impression that the complete elimina- 
tion of the effect of "jump" which could be effected by a recoiling 
bairel, such as has been used in some repeating rifles, would lead to 



* The fact that in this rifle Tariation of 
roMced by the late Sir Henrjr Halford. 



' jump " had a correctiye ofleot was 



344 



Vibrations of Rifle Barrels. 



improved accuracy in shooting ; but in view of the above reaulte it 
would appear that this is not the case.* 

The present inquiry shows that in the design of a rifle it is most 
important to consider the relations between the explosion force and 
the natural periods of the rifle, considered as an elastic structure, and 
that probably the compensating eifect above mentioned might be made 
of more iise than it is at present. 

For this purpose the explosion curves for various classes of ammuni- 
tion and the variations to which they are liable should be accurately 
known, and the proportions and length of the barrel, as well as the 
attachment of the barrel to the stock, should be so arranged with 
regard to the nodes of the system as to make variation of " jump " 
with the variation of initial velocity most nearly balance, within certain 
ranges, the alteration in the trajectory which gravity would otherwise 
eifect in virtue of the altered initial velocity. 

To show the sort of advantage which may be obtained by this 
means, we may, for example, suppose the rifle to be so constructed 
that for some particular class of ammunition the variation of " jump " 
due to a ± 40 f.s. of initial velocity causes downward or upward 
variation of 6' in the initial direction of the shot. Then by subtracting 
6' from E in Table VII, and multiplying by R, we get the following 
results : — 

Table VIII. 

Error due to ± 40 f.s. in initial velocity. 

Error 



Without jump. 
100 yards ± 0-14 feet. 



500 
1000 
1500 
2000 
2500 



M7 

3-8 

7-8 

13-8 

230 



With jump. 

+ 0-38 feet. 
1-70 „ 
1-26 „ 
000 „ 

±315 „ 
9-8 „ 



Such a correction, if it can be realised without an inconvenient 
construction of the mechanism, would be valuable for military piu*- 
poses now that long-range fire is becoming of such great importance. 

• There is anotlier form of ** jump," liowever, in the Lee-Enfield rifle, whose 
absence is most desirable, as it introduces horizontal moTements of the barrel. It 
depends, not on the acceleration of the shot, but on the statical pressure of the 
powder gas acting on an unsjmmetrical breech-cloffing action, and the remedy, as 
well as the disadTantages, are so clear in this ease as not to call for further remark. 



A Conjugating ** Yeast" 345 



" A Conjugating ' Yeast.' *' By B. T. P. Barker, B.A., Gonville 
and Caius College, Cambridge. Communicated by Professor 
Marshall Ward, F.R.S. Keceived May 4, — Read June 6, 
1901. 

(Abstract.) 

At the outset, the idea of a true yeast (Sacchuromyces) which conju- 
gates may appear anomalous in the extreme, but it is not improbable 
that such an event has been observed before in such organisms, though 
the phenomena have been misinterpreted. 

The yeast which is the subject of this communication was obtained 
from commercial ginger, pieces of this substance being placed in sterile 
saccharose-Mayer solution and kept at 25* C. until the organisms 
situated on the surface of the ginger had attained vigorous growth. 
These were separated by means of fractional plateKJultures of beer-wort 
gelatine. 

The colonies of the yeast-form, as seen on beer-wort gelatine plate- 
cultures, appeared to the naked eye as small rounded white dots, about 
the size of a pin's head. Under the low power of the microscope 
colonies on the siu-face of the gelatine had regular edges, while sulv 
merged colonies had a woolly appearance, due to numerous radiating 
branches. 

A pure culture was obtained from a colony developed from a single 
cell kept under observation in a hanging drop of beer-wort gelatine. 

Streak cultures on beer-wort gelatine and beer-wort agar are of a 
milky-looking brownish-white colour, and have well-marked regular 
crenate edges. Streak cultures on potato and bread are milky-white 
when moist, and chalky-looking when dry ; on pieces of moist ginger 
their colour is darker. 

A yeast-ring is formed in old cultures on many liquid media, but no 
films are produced. In tubes of beer-wort, which have been actively 
fermenting, the ring makes its appearance in 10 — 14 days at 25° C. 
It is milky-white in coloiu*, and looks like a layer of cream, deposited 
around the edges of the liquid. Such rings are also formed on dextrose- 
Mayer, Isevulose-Mayer, saccharose-Mayer, and maltose-Mayer solutions, 
being particularly well developed on those liquids which have undergone 
an active fermentation. 

The vegetation of the cultures described consists of typical ovoid and 
round yeast cells, and in the older cultures a few sausage-shaped and 
many irregular cells also, some of the latter containing spores. 

Reproduction by budding in a typical yeast-like manner is the usual 
method of growth, taking place best at 26 — 30** C, the maximum and 
minimum limits being 37 — 38** C. and 10 — 13** C. respectively. 

Reproduction by spores occurs under the usual conditiotv^ <^i «^x<i- 



346 Mr. B. T. P. Barker. 

formation for the Saccharomycetes. The gypsum-block matliod gtrm 
a plentiful supply, while spore-containing cells are frequently found in 
old cultures on nutrient media, whether solid or liquid. The stKure- 
containing cells differ from those of most other Saccharomyoetes in 
being compound cells, ue.^ they consist of two ordinary ovoid or round 
cells which have conjugated by means of a beak developed from each, 
the tips of the beaks fusing, the process thus resembling the weU-known 
case of conjugation of many Alg» and Fungi. The compound cells 
are thus made up of two ordinary yeast-like cells joined together by a 
narrow neck, the length of which varies according to the circumstances 
under which spore formation has taken place. 

Details of the process have been observed in hanging-drops of distilled 
water, in which have been placed a number of vigorously growing cells, 
the temperature being kept about 25"* C. The cells, originally clear 
and homogeneous, in a few hours began to grow vacuolated, and 
numerous bright-looking granules made their appearance. In twelve 
or more hours after sowing, a beak-like tubular process was put forth 
by many of the cells. The beaks of two neighbouring cells grew 
towards each other until their tips were in contact. Fusion of the 
walls then took place at the point of contact, being followed by the 
fusion of the protoplasmic contents of the beaks, which were clearer 
and brighter than the rest of the protoplasm in the cells. In a few 
hours after fusion, the protoplasm began to contract in the cells, and 
small round masses were formed : these eventually developed into the 
spores. 

The bright granules in the cells arranged themselves into groups in 
connection with the above masses and formed a network around them, 
the final differentiation of the spores being completed by the formation 
of a cell-wall around each mass. The size of the ripe spore is 4 — 5 fi ; 
and the number in each compartment of the mature cell varies from 
one to four, the most common arrangement being two in each. 

The spores germinate in a normal manner. After swelling they bud 
like ordinary yeast-cells. Fusion of spores in some cases seems to 
occur before germination. The optimum temperature for spore forma* 
tion lies between 25" C. and 30'' C, the first signs of spores appearing 
in 16 — 24 hours. At 34* C, 32 — 36 hours are required, and at 
36—37** C, 2 — 3 days. Above 38' C. no spores are formed. At 
13 — 15* C., 10 — 14 days are required, and below 13" C. practically no 
spores are produced. 

When heated for 10 minutes in beer-wort the spores are generally 
killed at 60" C, but some withstand an exposure of 5 minutes to a 
temperature of 65° C. 

In old cultures on nutrient media, and in spore cultures where the 
conditions were not of the most favourable character for the formation 
of spores, many cells of exceedingly irregular shape are found. These 



A Conjugating " Teastr 347 

are apparently produced from the ordinary ovoid or round cells during 
efforts at spore-formation. Beaks are formed at different points of the 
cell, but no conjugation takes place ; or, if it does occur, no spore 
formation follows. Consequently cells of great irregularity in shape 
result, and such may be considered as cells which have made attempts 
at spore-formation, but have failed owing either to lack of energy or 
substance in themselves, or to imfavourable external conditions. 

The behaviour of the nuclear contents during conjugation and spore- 
formation is suggestive. Stained preparations of cells in different 
stages of these processes show that the tips of the beaks are occupied 
by a deeply stained mass, which on conjugation fuses with a similar 
mass in the beak of the other cell which takes part in the process. The 
fused mass then divides into two, one portion withdrawing into each 
compartment of the compound cell ; there division again takes place, 
in such a way as to provide the basis of each spore about to be formed. 
Previous to the latter division a deeply stained and prominent granular 
network becomes arranged around each mass, and this separates into 
groups when the final division occurs, the number of groups corre- 
sponding with the number of masses. 

By this time each mass is rounded off into a spherical body — the 
young spore — and around each spore a group of granules is arranged 
and eventually a wall is formed. The spores then ripen. Lack of 
knowledge as to the exact nature of the yeast nucleus prevents a com- 
plete interpretation of the histological facts observed, but it seems 
certain that the deeply stained masses are nuclear in nature, and that 
consequently a kind of nuclear fusion takes place. If so the process 
must be looked upon as a simple sexual act, somewhat similar to that 
occurring in the process of spore-formation of Schizchsaccharomyces odo- 
sporas. 

Alcoholic fermentation is produced in beer-wort by this yeast. It 
also ferments laevulose vigorously, and dextrose and saccharose slightly. 
Maltose, lactose, and dextrin are not fermented. A mixture of dextrose 
with maltose and dextrin is fermented more freely than dextrose alone. 
Long-continued cultivation in beer-wort seems to have increased its 
fermentative activity for that medium. 

In conclusion, there seem to be three possible views regarding the 
nature of the fusion-process, viz. : (1) It is an abnormal or pathological 
phenomenon due to the conditions of culture ; (2) it is a mere cell- 
fusion, such as frequently occurs between contiguous cells in fungi; or 
(3) it is a true sexual process, such as is now known to occur in 
many fungi. 

The first view seems unlikely, since the result of the process is the 
production of normal healthy spores, and the conditions are exactly 
such as are generally efficacious in the production of spores in yeast of 
all kinds. 

VOL. LXVIII. "J^ ^ 



348 Messrs. O. F. G. Searle and T. G. Bedford. 

The second view receives a certain amount of support from the faet 
that such fusions are known in other yeasts, e.^., SaeAmtmijfeei 
Ludwigii (Ebns), but in these cases growth is active, and there does 
not seem to be any nuclear fusion. 

Having regard to the behaviour of the nuclear contents and the 
subsequent formation of spores, the third view seems most likely. 
Looking upon the process then as a sexual act of the simplest kind, 
and in view of the fact that^ while all its other characters accord with 
those of Saccharomyces, it differs from the latter in the manner of its 
spore-formation, it is proposed to place it in a new genus, Zfgth 
saccharomyces^ on the analogy of the genus Schiso-saccharomyces, 
suggested by Beyerinck for the fission-yeasts. 



" The Measurement of Magnetic Hysteresis." By G. F. G. Siablb, 
M.A., and T. G. Bedfobd, M.A^ Communicated by Professor 
J. J. Thomson, F.B.S. Eeceived May 2, —Bead June 6, 1901. 

(Abstract.) 

§ 1. In 1895 one of the authors described* a method of measuring 
hysteresis by observation of the throw of a ballistic electro^ynamo- 
meter. The method in its most elementary form is very simple. An 
iron ring of section A and mean circumference I is uniformly wound 
with N/ turns of primary winding, and the primary current C passes 
also roimd the fixed coUs of an electro-dynamometer. A secondary 
coil of n turns wound on the ring is connected in series with the 
suspended coil of the dynamometer and an earth inductor, the total 
resistance of the circuit being S. 

The effects of self-induction in the secondary circuit being neglected, 
the secondary current c is 

Aw^ 
S dt ' 

If the couple acting on the suspended coil duo to the currents C, c 
be qCc, then at any instant 

Couple = 30 = 3 ^-^nf, 

since H = 47rNC, when the magnetic force due to c is neglected. 

If the instrument be used ballistically, the angular momentum 
acquired by the coil while C changes from Co to - Go, is 

* G. F. C. Sesrle, " A Method of Measuring the Loss of Energy in Hjttansb/* 
'Okmb. Phil 80c,, Proo./ toI. 9, Fart 1, 11th Noremher, 1895. 



The Measv/remewt of Magnetic Hyderesis. 349 

Now let the earth inductor be inverted, and so produce a change of 
induction P, and let the primary current at the time be C\ then 

If ^1, 6'2 be the two throws which occur when C changes from C© to 
- Cq and from - Cq to C^, and if <^ be the throw due to the earth 
inductor, then ^/<^ ■= (o/w and thus for a complete cycle, 



W = iH = Tnf<''>-^^^)- 



Thus the sum of the two throws ^i and 0^ is a measure of the 
energy dissipjited in hysteresis in a complete cycle. When the factor 
C PN/Atk/) has been determined, measurements of hysteresis can be 
made as rapidly as measurements of induction with a ballistic galvano- 
meter. 

§ 2. In developing a more complete theory the authors employ the 
equations 

E = RC + -^(N/AB + L'C + Mc), 

= Sc + ^(iiAB+MC + Lc). 

With the aid of the principle of the conservation of energy, these 
equations lead to the result 






= U-X-Y. 

Here o- is the specific resistance of the specimen, and Q a niunerical 
constant depending upon the geometrical form of the section, having 
the value I/Stt or 003979 for a circle and 0-03512 for a square. 

The term U is determined by the dynamometer throws. The term 
X is the energy dissipated in eddy currents in the specimen during the 
two serai-cycles, and Y is roughly the energy spent in heating the 
secondary circuit. 

It is shown that Y, when appreciable, can be determined by making 
two observations for U with two different values for S. In the 
authors' experiments Y was nearly always negligible. When a 
suiUible key is employed to reverse the current, X + Y can be 
determined by making two observations for U with two different 
resistances of the primary circuit, the E.M.F. being at the same tmie 
so altered as to produce the same maximun^ cwrtgnVt O^ Vcw ^bf^ ^N^ 



360 Mesan. O. F. G. Searle and T. G. Bedfoid. 

This method of determining X + T has lately been used suooeflsfally 
at the Gayendiflh Laboratory by Mr. & L. Wilb in the caae of 
specimens of large section. In the authors' experiments X waa 
generally negligible. 

As the corrections X and Y depend upon tKi/di it is neoessary that 
the primary current should change only gradually. By inserting a 
choking coil of great self-induction in the primary oireuit, and by 
using a special key to cause the reversal of the current, this end is 
satisfactorily attained. 

The authors have made many comparisons between the values of 
W found by their method and those calculated from the areas of 
cyclic B-H curves obtained by a ballistic galvanometer, and have 
found satisfactory agreement. 

§ 3. By using a ballistic galvanometer in addition to the dynamo- 
meter, the two authors were able to make simultaneous observaticms of 
the range of the magnetic induction ± Bq and of the energy dissipated 
in each cycle. The range of the magnetic force ± H^ was also 
observed. 

It was found that the cyclic B-H curve is not always divided into 
two parts of equal area by the lino H = 0. The oflFect is well 
marked in the case of an iron wire freshly annealed, and sometimes 
does not disappear in spite of many reversals. 

When the magnetic force is reversed many times both Bq and W 
decrease. The effect is most apparent in soft iron freshly annealed, 
and subjected to a small magnetic force. Thus when the limits of H 
were ± 2*5, in the first cycle after the annealing, Bo = 2220 and W 
= 598. In the forty-first cycle B^ = 1840, W = 433. 

§ 4. When an iron wire is stretched by a variable load, and is put 
through cycles with the limits ± Ho, the first application of the 
tension results in an increase in both B^ and W. As the tension 
increases, Bo and W reach maxima and then decrease. The effect is 
more marked when Ho is small than when it is large. Thus with a 
wire of section 0'00708 cm.- a load of 16 kilos, raised Bo from 1233 to 
5870 and W from 494 to 3820, with H© = 4-524. 

A series of experiments was made upon the effects of torsion. 
Wlien Ho is kept constant, as the torsion increases there is a large 
decrease in both Bo and W. Thus in the case of a soft iron wire when 
H = 30, by torsion within the elastic limit Bq was brought down 
from 2280 to 1070 and W from 907 to 276. Further, both B^ and 
W exhibit hysteresis with respect to the torsion. 

Experiments were also made in which the torsion was gradually 
increased till the wire broke. In other experiments the authors 
studied the influence of permanent torsional set upon the effects of 
cycles of torsion. They abo examined the development of a cyclio 
BtAte, for cycles of torsiof, after initial permanent torsional set. 



The Measurement of Moffnetic Hysteresis, 351 

In all these experiments, the curves showing W in terms of the 
stress, bear a close resemblance to those showing Bo in terms of the 
stress. To examine this point, curves were plotted showing how W 
varies with Bo, when Hq is kept constant and Bq is varied by varying 
the stress. 

For both tension and torsion each curve for a given value of Ho 
takes the form of a straight line having a hook at one end. The 
straight portions of the separate curves for different values of Hj^ all 
pass, on prolongation, through a single point, generally on the line 
Bo = 0. Thus the straight parts are represented by W = wBo - 6. 
Plotting m against Ho it is found that m = aHoS ^^^ ^^us the formula 
becomes W = rtHo*Bo - ^, where a and h are constants. It is found 
that this formula represents W closely when both Ho and Bo vary over 
a considerable range in the neighbourhood of the maximum permea- 
bility, the iron being now free from stress. 

§ 5. An electric current flowing along an iron wire magnetises it 
circularly, and may be expected to diminish both B^ and W for the 
given limits ± Ho. Experiment showed that the expected effect occurs, 
a current of ri23 ampere through an iron wire about 1 mm. in 
diameter diminishing W by 22 '7 per cent. 

§ 6. The numerical values of the quantity Q, which occurs, in § 2, 
in the expression for the heat produced by the eddy currents in the 
specimen, are calculated in Appendix I for rods of both circular and 
rectangular sections. 

§ 7. In their experiments the authors have used straight iron wires 
about 50 cm. in length. They discuss the effect of the de-magnetising 
force due to the induced magnetism of the specimen, and show how 
to apply corrections to the value of W calculated from the formula 
l/i'T . JHV/B', where H' is the magnetic force due to the current, 
and B' is the magnetic induction at the centre of the wire; they 
also give niunerical examples of these corrections. Appendix II 
contains an account of experiments made to find the de-magnetising 
force /i under two sets of conditions. In the first case, h was determined 
when H = Ho, after many magnetic cycles with the limits ± Ho. Using 
a freshly annealed wire, and increasing Ho from to 124 C.G.S., h was 
found to rise to a maximum, which occurred nearly when ft had its 
maximiun value ; the maximum was followed by a minimum of A, and 
the value of h for the largest values of Ho was less than that which would 
obtain if the induction through the centre of the wire flowed in and 
out only by the ends of the wire. This small value of h implies the 
existence, between the centre and either end of the wire, of a "pole " 
of sign opposite to that of the pole at the end, a circumstance only 
to be accoimted for by the effects of hysteresis. In the second case 
h was found for several points on the cyclic B-H curve^ and ^wscn^'^ 
are given showing h in relation to both H and 'B. \\i \«\Jcl ^^x^^^»\^ 



352 Thernud Adjtuiment a^id JReqriraicrjf Exchange. 

exhibits very marked hysteresis with respect to H and B. Over apart 
of the cyclic ^B curve, the direction of A is opposite to that c<»rrespond- 
ing to the direction of the induction at the centre of the wire. The 
results obtained show that the method of '* shearing" usually adopted 
to correct B-H curves for the effects of the de-magnetising force must 
be used with great caution. 

The paper is illustrated by diagrams of apparatus and by carves 
showing the experimental results. 



'' Thermal Adjustment and Eespiratory Exchange in Monotremes 
and Marsupials. — ^A Study in the Development of Homo- 
thermism." By C. J. Mabtin, M.B., D.Sc., Acting Professor 
of Physiology in the University of Melbourne. Communi- 
cated by E. H. Starling, F.RS. Received May 14, — Reatl 
June 6, 1901. 

(Abstract.) 

A number of observations on the relations l)etween the body tem- 
perature, and the temperature of the surrounding medium, and on the 
respiratory exchanges in monotremes and marsupials are recorded. 
The results are compared with those obtained in control experiments 
with cold-blooded animals (lizards) and higher mammals. 

The main conclusions arrived at are — 

1. Echidna is the lowest in the scale of warm-blooded animals. Its 
attempts at homothermism fail to the extent of lO'' when the environ- 
ment varies from 5** to 35"* C. During the cold weather, it hibernates 
for four months, and at this time its temperature is only a few tenths 
of a degree above that of its surroundings. The production of heat in 
Echidna is proportional to the difference in temperature between 
animal and environment. At high temperatures, it does not increase 
the niunber and depth of its respirations. It possesses no sweat glands, 
and exhibits no evidence of varying loss of heat by vaso-motor adjust- 
ment of superficial vessels in response to external temperature. 

2. Ornithorhyncus is a distinct advance upon Echidna. Its body 
temperature though low is fairly constant. It possesses abundant 
sweat glands upon the snout and frill, but none elsewhere. The pro- 
duction of carbonic acid with varying temperatures of environment 
indicates that the animal can modify heat-loss as well as heat-produc- 
tion. Its respiratory efforts do not increase with high temperatures. 

3. Marsupials show evidence of utilising variations in loss to an extent 
greater than Ornithorhyncus, but less than higher mammals. Their 

respirations slightly increase in number sA hi^h temperatures. 



On the Elastic EquUibi^ium of CirctUar Gylinde^'S, 353 

4. Higher mammals depend principally upon variations in heat-loss, 
in which rapid respiration plays an important part. 

5. Variation in production of heat is the ancestral method of homo- 
thermic adjustment. During the evolution of the warm-blooded 
animal it has, through developing a mechanism by means of which it 
can vary production in accordance with heat lost, overcome one dis- 
advantage of cold-blooded animals, viz., that activity is dependent on 
external temperature. It has thereby increased its range in the 
direction of low temperatures. Later, by developing a mechanism 
controlling loss of heat, it has increased its range in the direction of 
high temperatures, and also rendered body temperature largely inde- 
pendent of activity ; these advantages have been gained by a greater 
expenditure of energy. 



" On the Elastic Equilibrium of Circular Cylinders under certain 
Practical Systems of Load." By L. N. G. Filon, M.A., B.Sc, 
Research Student of King's College, Cambridge ; Fellow of 
University College, London ; 1851 Exhibition Science Ee- 
search Scholar. Communicated by Professor EwiNG, F.E.S. 
Eeceived May 20,— Eead June 6, 1901. 

(Abstract.) 

The paper investigates solutions of the equations of elasticity in 
cases of circular symmetry, and it applies them to discuss the elastic 
equilibrium of the circular cylinder under systems of surface loading 
which do not lead to the simple distributions of stress usually assumed 
in practice. 

The analytical method employed has been to solve the equations of 
elasticity in cylindrical co-ordinates, obtaining solutions in the typical 

form . < kz > x (function of r), r being the distaiice from the axis 

and z the distance measured along the axis. 

More general solutions, not necessarily symmetrical about the axis, 
have been given by Professor L. Pochhammer* and by Mr. C. Chree.t 
l^rofessor Pochhammer has used his results to deduce approximate 
solutions for the bending of beams. Neither Mr. Chree nor Professor 
Pochhammer has, so far as I am aware, worked out his solutions in 
detail for such problems as are discussed in the present paper. 

I found that solutions in trigonometrical series would be sufficient to 
satisfy most conditions in the first of the three cases discussed, and all 

• ' Orelle's Joumal/ vol. 81. 

t * Cftmbridge Phil. Soc. TtwM.,' 7oV.\4; 



354 Mr. L. K G. Filon. On the JEUutic EquOOifiwm iff 

conditions in the third. The second case required the introdndioa of 
other typical solutions, and the analysis was more intricate. 

The three problems investigated are as follows : — 

In the first I consider a cylinder under pull, the pull not being 
applied by a uniform distribution of tension across the plane ends, but 
by a given distribution of axial shear over two zones or rings, towards 
the ends of the cylinder. 

The second is that of a short cylinder compressed longitudinally 
between two rough rigid planes, in such a manner that the ends are 
not allowed to expand. 

The third case is that of the torsion of a bar in which the stress is 
applied, not by cross-radial shears over the flat ends, as the ordinary 
theory of torsion assumes, but by transverse shears over two xonea or 
rings of the curved surface. 

The first problem corresponds to conditions which frequently occur 
in tensile tests, namely, when the piece is gripped by means of pro- 
jecting collars, the pull being in this case transmitted from the collar 
to the body of the cylinder by a system of axial shears. 

Analytical solutions are found when this system of axial shears is 
arbitrarily given, there being given also an arbitrary system of radial 
pressures. Approximate expressions are deduced when the length of 
the cylinder is large compared with its diameter. These show that 
the strains and stresses may be calculated on the assumption that we 
have, over any cross-section, a uniform tension across the section, a 
constant radial pressure and an axial shear proportional to the distance 
from the axis, the last two occurring only over the lengths of the 
cylinder where such stresses are applied. The eflects of local pressure 
and shear are thus, for a long cylinder, restricted to a small region 
and, in the free parts of the bar, we have, to this approximation, the 
state of things assumed by the ordinary theory. 

In order, however, to study the effect of such a system of surface 
stresses, when no approximations are involved, I have worked out 
numerically a case where there is no radial pressure applied externally, 
and a imiform axial shear is applied between two zones. The solution 
gives zero tension across the plane ends; it is not, however, found 
possible to fulfil completely the condition of no stress, and we have 
over these limiting planes a self-equilibrating system of radial shears, 
which, however, will produce little effect at a distance from the ends. 
The length of the cylinder is taken to be 7r/2 times the diameter, this 
ratio being found to simplify the arithmetic. The two rings of shear 
extend each over one-sixth of the length and are at equal distances 
from the mid-section and the two ends. 

In this and the other numerical examples, Poisson's ratio has been 
taken as one-fourth. This is not correct for most materials, but as the 
object W&8 to find out the differences between the results of the aimpie 



Gircviar Cylinders wider certain Practical Systems of Load. 355 

and the modified theories, rather than to calculate the absolute stresses 
and displacements for any given material, the exact value of Poisson's 
ratio adopted was comparatively unimportant. 

It is then found that the stress is greatest at the points where the shear 
is discontinuous, i.e., at the ends of the collar in a practical case. At 
these points it is theoretically infinite. This result is true whatever 
the dimensions of the cylinder. For materials like cast iron or hard 
steel, which are brittle, such points would therefore be those of greatest 
danger ; but in such a case as that of wrought iron or mild steel, for 
instance, the stress will be relieved by plastic flow. 

The tensile stress varies considerably over the cross-section, and the 
distortion of the latter is large. Towards the middle of the bar, the 
axial displacement at the surface is, roughly, twice what it is at the 
centre. 

In tensile experiments the elongation is usually measured by the 
relative displacement of two points on the outer skin of the cylinder, 
as recorded by an extensometer. When the test-piece is seized in this 
way, the surface stretches more than the interior, and consequently a 
negative correction should be applied to the readings of the extenso- 
meter. In the somewhat extreme case considered, this correction may 
amount to as much as 30 per cent. 

The lateral contraction is very much smaller than the theory of 
uniform tension indicates, being in fact never so great as 60 per cent, 
of the amount calculated on that hypothesis. For points inside the 
material the discrepancy is still greater. These variations appear due 
to the fact that there are considerable radial and cross-radial tensions 
inside the material, these tensions being often equal to about one-fifth 
of the mean tension Q, which would give the same total pull. 

Tables are given in the paper showing the values of the radial and 

x*^ y"^ y*"^ x*^ 

axial displacements u and u\ and of the four stresses rr^ zz^ rz^ <fxl> 
(in the notation of Todhunter and Pearson's * History of Elasticity,* 

st being the stress, parallel to s, across a face perpendicular to t) for 
points in the cylinder at distances from the axis == 0, •2a, •4(i, '6a^ a ; 
a being the radius of the cylinder ; and for intervals of length parallel 
to the axis equal to tenths of the half-length. These tables are 
ilhistrated by curves and diagrams. 

The second problem is of considerable importance, as it illustrates 
the crushing of blocks of cement or stone, when they are compressed 
])etween iron planes, or between sheets of mill-board, so that their ends 
are constrained not to expand. 

The analytical solution is made up, partly of a finite nimiber of 
terms which are algebraic and rational in r and z, and partly of infinite 
series involving sines and cosines containing z. By suitably combining 
these two types of terms all the conditions can be satiafiod. 

The niunerical example taken was one in -wlaieb. \\i^\«a^^iNs. \\s»2t\:^ 



386 Mr. L N. O. FUon. On the EkutU BgwiWmim qf 

equal to the diameter — the exact ratio, r/8, being ohoeen so aa to 
simplify the arithmetic as far as possible. 

As in the preceding example, tables of the stresses are given for a 
large number of points in the cylinder. From these the principal 
stresses and the principal stretch were calculated; and again from 
these, by interpolation, curves were drawn showing the loci of points 
in the cylinder where the greatest stress, the greatest stretch, or the 
greatest stress-difference had the same value. 

The curves show that, whatever theory of yielding is adopted, 
namely, the greatest^itress theory of Navier and Lam^, or the greatest 
strain-theory of St Venant, or the greatest stress difference (or greatest 
shear) theory which has more recently been put forward, failure of elas- 
ticity will begin to take place round the perimeter of the {dane ends. 

Thus, in the case of the stress, consider the regions where the stress is 
greater than a certain value S. When S is nearly equal to the greatest 
stress these regions are thin annuli round the ends. As S diminishes 
the regions become made up, partly of such annidi (of increasing 
thickness), partly of a closed region round the centre of the cylinder. 
When S reaches a certain critical value, S^, these two regions join on 
to one another. The regions where the stress is less than So consist of 
caps at the two ends and of cylindrical shells, forming the '* skin " of 
the cylinder. 

The regions of least stress consist only of caps or buttons of material 
at the two ends. 

The variations of the principal stretch and of the principal stress- 
difference can be described in the same general teims. 

For materials like stone and cement, which have no very definite 
yield point, the elastic distribution will give at least an indication of 
the state of stress almost up to the point of rupture, and if it be 
assumed that the latter takes place over the regions of greatest stress, 
or greatest strain, or greatest shear, according to the particular theory 
we adopt, the results above show that the fracture will start from the 
perimeter of the ends, and that caps or buttons, which may have an 
approximately conical shape, will probably be cut off at the ends. 

The fact that yielding first occurs at the perimeter, when the stress 
exceeds 1/1-686 of the limiting stress for uniform pressure, leads to 
the conclusion that the strength of a cylinder under this system of 
stress is considerably less than the strength of a cylinder uniformly 
compressed. This result apparently contradicts the fact that the 
strength of stono and cement, when tested between lead plates, which 
allow of expansion, is very much less than when tested Ijetween mill- 
board which does not allow of expansion, a fact which has led Pro- 
fessor Perry to state that the true strength of such materials is about 
half their published strength. (* Applied Mechanics,' p. 345.) 

The contradiction, however, seems to be explained by a remark of 



Circular Cylinders under certain Praetieal Systems of Load. 357 

Unwiii's (* Testing of Materials of Construction/ p. 419), which is 
corroborated by Professor Ewing, to the effect that lead, which is a 
plastic material and flows easily, not only does not hinder expansion 
of the ends of the block, hnt forces it. 

It is shown in the paper that, under such conditions, whenever the 
forced expansion exceeds the natural lateral expansion of the stone 
or cement, which it practically always does, then the points of failure, 
instead of being at the perimeter of the ends, are at the centre, and 
the limiting stress, under these circumstances, may be much less than 
that obtained for non-expanding ends. Further, this limiting stress 
depends upon the amount of flow of the lead and has no fixed value — 
a conclusion confirmed by the experimental results of Unwin. The 
mill-board test, on the other hand, should give consistent results, 
although it really introduces too large a factor of safety. The change 
in the form of the fracture, noticed by Unwin, is also accounted for by 
theory. 

The values of the apparent Young's modulus and of the apparent 
Poisson's ratio are investigated. Young's modulus is shown to vary^ 
between its true value, when the cylinder is long, and the value of 
the ratio of stress to axial contraction, when lateral expansion is pre- 
vented by a suitable pressure, this last corresponding to the case when 
the cylinder is made very short. 

In the given example, Poisson's ratio is apparently 0*269, the actual 
value assumed being 0*25. It should diminish down to zero as the 
cylinder becomes indefinitely short. 

The third problem corresponds to the case of a cylinder whose ends 
are surrounded by a collar so that the applied torsion couple is 
transmitted to the inner core by means of transverse shear. 

A general solution is first found for a given arbitrary system of 
transverse shear. Approximate expressions are given when the length 
of the cylinder is large compared with its diameter. These show 
that, to the first approximation, the cross-sections remain undistorted, 
radii originally straight remaining so. The shear across the section, at 
any point of it, is connected with the total torsion moment at that 
section by the same relation as in the ordinary theory of torsion. A 

transverse shear r4> varying as the square of the distance from the 
axis exists over the lengths of the cylinder subjected to external 
stress. 

As a numerical example a cylinder is considered, whose length is 
w/2 times its diameter, and which is subjected, over lengths at the 
ends, each equal to one-fourth of the whole length, to a uniform 
transverse shear. Using the exact expressions found, the stresses and 
transverse displacement are calculated for various points, and these 
arc compared with the values calculated from the approximate ex:QY«ir 
sions when the cylinder is long. 



868 Mr. B. D. Steda ne Meagmmunt qfltmic VOocitui 

It is found that the agreement is, on the whole, toleraUy good, 
whence it is inferred that in torsion, the eflisct of looal actkm dies out 
more rapidly than in tension or compression. The only case of 

obvious divergence is with regard to the shear r^ This shear peraista 
inside, even at sections where no stress of this kind is applied to the 
outside of the cylinder, but it continually diminishes as we recede from 
the ends. 

In the exact solution, the cross-sections do not remain imdistorted, 
the transverse displacement increasing- more rapidly than the radius. 
The distortion is small at sections where there is no external applied 
stress, but is very obvious near the ends. 

Further, when the applied transverse shear varies disoontinuously, 
as in this case, the other stress becomes infinite at the points of dis- 
continuity. This suggests why it is that abrupt changes in the section 
of such a cylinder are dangerous. The projecting parts acting upon 
the inner core will introduce a sudden change in the transverse shear. 
It has been noticed that propeller shafts usually break at such points. 



"The Measurement of Ionic Velocities in Aqueous Solution, and 
the Existence of Complex Ions." By B. D. Steele, B.Sc., 1851 
Exhibition Scholar (Melbourne). Communicated by Pro- 
fessor Eamsay, F.RS. Received May 10, — Bead June 6, 
1901. 

(Abstract.) 

The method of measuring ionic volocities described by Masson has 
been extended in such a manner that, by the present method, the use 
of gelatin solution and of coloured indicators is not necessary. 

An aqueous solution of the salt to be measured is enclosed between 
two partitions of gelatin which contain the indicator ions in solution, 
the apparatus being always so arranged that the heavier solution lies 
underneath the lighter. On the passage of the current the ions of the 
measured solution move away from the jelly, followed at either end 
by the indicator ions ; the boundary is quite visible in consequence of 
the difference in refractive index of the two solutions. The velocity 
of movement of the margins is measured by means of a cathetometer, 
and the ratio of the margin velocities gives at once the 'ratio of the 
ionic velocities. 

It is found that, for the production and maintenance of a good 
refractive margin, a certain definite range of potential fall is required 
for any given pair of solutions, and this range differs very much for 
different boundaries — for example, the margin potassium acetate 



t7i Aqueous SoltUion, and the Existence of Complex Ions. 359 

QC ' 

following potassium chloride, or K ^ is stable with a potential fall of 

cd 
0*82 volt, whilst for the stability of the — SO4 margin, a voltage of 

2*54 volts at least is necessary. 

The explanation of this is to be looked for, not in the fall of potential 
in the measured solution, to which the above figures refer, but rather 
to the change of potential fall on passing from the indicator solution 
to the latter, and is probably connected in some manner with the 
Nernst theory of liquid cells. 

Certain regularities in the influence of different salts on the melting 
points of the jellies have been noted, and it seems that this influence 
is more or less of an additive nature, depending on the nature of the 
anion and of the cation. Amongst anions the SO4 ion has the least, 
and the I and NO3 ions the greatest, effect in lowering the melting 
point. Amongst cations, the K ion has a much less influence than the 
Li or Mg ions : these relations are as yet, however, only qualitative. 

The values for the transport number that have been obtained 
show a remarkable agreement with Masson's figures, as measured in 
gelatin, for potassium and sodium chlorides. On the other hand, for 
lithium chloride and magnesium sulphate no such agreement exists. 
For all the salts a comparison with Hittorf 's figures shows only an 
approximate agreement, being about as good at that shown by a com- 
parison of the figures for the same salt, as measured by different 
investigators, by the indirect method of Hittorf. 

From a knowledge of the specific resistance of the measured solution 
it is possible to calculate the potential fall in this part of the system, 
and from this the absolute average velocity U = xu, where x = the 
coefiicient of ionisation, and u the absolute ionic velocity. A very 
striking agreement holds between the sum of the velocities of anion 
and cation and the sum as calculated from Kohlrausch's conductivity 
figiu-es. The velocities of a large number of ions at different concentra- 
tions of different salts have been calculated, and the velocity of the 
hydrogen and hydroxyl ions have been also measured, with the following 
results : — 

Found. Calculated. 

OHinKOH, 0-5N 0001435 0-00145 

„ NaOH, 0-2N 000158 0*00152 

H in HNOs, 0-2N (^*^^^f«) 0*00280 

10*00272/ 

The ratio of the current, as measured by the galvanometer, to that 
calculated from the velocity of the margins in the manner indicated by 
Masson, is found to be equal to unity only for a few salts of the type of 
potassium chloride ; for other salts this ratio has a vaVvx^ \w ^crox^ ^w^% 

VOL. LXVIII. "1 Vi 



360 Prof. J. Dewar. 

greater, in others less, than 1. The same irregularity has been prevmudy 
pointed out by Masson for the gelatin solutions of the mdphatai oi 
magnesium and lithium. 

The attempt is made to explain this deviation from the requiranifliita 
of theory, and also the difficulty that Eohlrausch is xmable to assign to 
dyad elements any value for the specific ionic velocity, which is 
the same when calculated from the measurements of different salts 
of the same metal, by the assumption, first advanced by Hittorf , that^ 
in concentrated solutions of these salts ionisation takes place in such 
a manner that there are formed complex ions in addition to simple 
ones ; and the conclusion is drawn that, in all cases where any consider- 
able change in transport number occurs with changes in concentration, 
complex ions are present to a greater or less extent. 



Jum 13, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, in the Chair. 

Mr. James Mansergh, Major Ronald Ross, Mr. Oldfield Thomas, 
Mr. William Watson, and Mr. William C. Dampier WTietham were 
admitted into the Society. 

A List of the Presents received was laid on the table, and tln^nlni 
ordered for them. 

The Bakerian Lecture, "The Nadir of Temperature, and Allied 
Problems," was delivered by Professor James Dewar, F.R.S. 



Bakerian Lecture. — ^*-The Nadir of Temperature, and Allied 
Problems. 1. Physical Properties of Liquid and Solid 
Hydrogen. 2. Separation of Free Hydrogen and other Grases 
from Air. 3. Electric Resistance Thermometry at the 
Boiling Point of Hydrogen. 4. Experiments on the Lique- 
faction of Helium at the Melting Point of Hydrogen. 5. Pyro- 
electricity, Phosphorescence, &c." By James Dewar, LLD., 
D.Sc, F.R.S., Jacksonian Professor in the University of Cam- 
bridge, and Fullerian Professor of Chemistry, Royal Institu- 
tion, London, &c. Delivered June 13, 1901. 

(Abstract.) 

Details are given in this paper which have led to the following 
results : — 
The helium thermometer which records 20*''5 absolute as the boiling 



The Nadir of Temperature, and Allied Problems, 361 

point of hydrogen, gives as the melting point 16" absohite. This 
value does not differ greatly from the value previously deduced from 
the use of hydrogen gas thermometers, viz., 16**'7. The lowest tem- 
perature recorded by gas thermometry is H^'S, but with more com- 
plete isolation and a lower pressure of exhaustion, it will be possible 
to reach about 13' absolute, which is the lowest practicable tempera- 
ture that can be commanded by the use of solid hydrogen. Until 
the experiments are repeated with a helium thermometer filled with 
helium, previously purified by cooling to the lowest temperature that 
can be reached by the use of solid hydrogen, the gas being under 
compression, no more accurate values can be deduced. 

The latent heat of liquid hydrogen about the boiling point as 
deduced from the vapour pressures and helium-thermometer tempera- 
tures, is about 200 units, and the latent heat of solid hydrogen cannot 
exceed 16 units, but may be less. 

The order of the specific heat of liquid hydrogen has been deter- 
mined by observing the percentage of liquid that has to be quickly 
evaporated under exhaustion in order to reduce the temperature to 
the melting point of hydrogen, the vacuum vessel in which the experi- 
ment is made being immersed in liquid air. It was found that in the 
case of hydrogen the amount that had to be evaporated was 15 per 
cent. This value, along with the latent heat of evaporation, gives an 
average specific heat of the liquid between freezing and boiling point 
of about 6. AMien liquid nitrogen was similarly treated for comparison, 
the resulting specific heat of the liquid came out 0*43 or about 6 
per atom. Hydrogen therefore appears to follows the law of Dulong 
and Petit, and has the greatest specific heat of any known substance, 
near its melting point. 

The same fine tube used in water, liquid air, and liquid hydrogen 
gave respectively the capillary ascents of 15 5, 2 and 5*5 divisions. 
The relative surface tension of water, liquid air, and liquid hydrogen 
are therefore in the proportion of 15*5, 2, 0*4. In other words, the 
surface tension of hydrogen at its boiling point is about one-fifth that 
of liquid air under similar conditions. It does not exceed one thirty- 
fifth part the surface tension of water at the ordinary temperature. 

The refractive index of liquid hydrogen determined by measuring 
the relative difference of focus for a parallel beam of light sent through 
a spherical vacuum vessel filled in succession with water, liquid oxygen, 
and liquid hydrogen, gave the value 1*12. The theoretical value of the 
liquid refractive index is 1*11 at the boiling point of the liquid. This 
result is sufficient to show that hydrogen, like oxygen and nitrogen in 
the liquid condition, has a refractivity in accordance with theory. 

Free hydrogen, helium, and neon have been separated from air by 
two methods. The one depends on the use of liquid hydrogen to Vi<^^ 
the dissolved gases out of air kept at a temperaXxxre iv^»x \3tvei tcl'^xIvw^ 

^ e. ^ 



362 Prof . J. Dewar. 

point of nitrogen; the other on a simple arrangement for keeping tba 
more volatile gases from getting into solution after separation by 
partial exhaustion. By the latter mode of working something like 
l/d4000th of the volume of the air liquefied appears as unoondenaed 
gas. The latter method is only a qualitative one for the recognition 
and separation of a part of the hydrogen in air. In a former paper on 
the " Liquefaction of Air and the Detection of Impurities,'^ it was 
shown that 100 c.c. of liquid air could dissolve 20 c.c. of hydrogen at 
the same temperature. The crude gas separated from air by the 
second method gave on analysis — ^hydrogen 32*5 per cent., nitrogen 
8 per cent., helium, neon, &c., 60 per cent. After removing the . 
hydrogen and nitrogen the neon can be solidified by cooling in liquid 
hydrogen and the more volatile portions separated. 

There exists in air a gaseous material that may be separated without 
the liquefaction of the air. For this purpose air has to be sucked 
through a spiral tube filled with glass wool immersed in liquid air. 
After a considerable quantity of air has been passed, the spiral is 
exhausted at the low temperature of the liquid air Iwith. The spiral 
tube is now removed and allowed to heat up to the ordinary tempera- 
ture, and the condensed gas taken out by the pump. After purifica- 
tion by spectroscopic fractionation, the gas filled into vacuum tubes 
gives the chief lines of xenon. The spectroscopic examination of the 
material will be dealt with in a separate paper by Professor Liveing 
and myself. A similar experiment made with liquid air kept under 
exhaustion, the air current allowed to circulate being, to prevent lique- 
faction, under a pressure less than the saturation pressure of the liquid, 
resulted in crypton being deposited along with the xenon. 

A study of fifteen electric resistance thermometers as far as the 
boiling point of hydrogen has been made, and the results reduced by 
the Callendar and Dickson methods. The foUoMring table gives the 
results for seven thermometers, viz., two of platinum, one of gold, 
silver, copper, and iron, and one of platinum-rhodium alloy. It will 
be noted that the lowest boiling point for hydrogen was given by the 
gold thermometer. Next to it came one of the platinum thermo- 
meters, and then silver, while copper and the iron differ from the gold 
value by 26 and 32 degrees respectively. The gold thermometer 
would make the boiling point 2 3** -5 instead of the 20** -5 given by the 
gas thermometer. Then the reduction of temperature imder exhaus- 
tion amounts to only V instead of 4** as given by the gas thermometer. 
The extraordinary reduction in resistance of some of the metals at the 
boiling point of hydrogen is very remarkable. Thus copper has only 
l/105th, gold l/30th, platinum l/35th to l/17th, silver l/24th the 
resistance at melting ice, whereas iron is only reduced to l/8th part of 
the same initial resistance. The real law correlating electric reeiatance 
• * Chem. Soc. Ppoc.,* 1897. 



The Nadir of Temperature, and Allied Prohlems. 363 



££ 



U I 






'o 



o 

e 



S.3 



i«5 






ii 



c3S 



oQdpdQ 



O ud eo 

O) CO CO 

04 t^ <c 



us — ^ 00 

Sl-H « iS CO 

o 5 rH Jgao 

o I ^ I 



00 00 

r^ r-l 

I I 



04 04 04 04 

II II 



04 t^ 

•^ I-" 
»0 1-1 



.- « » 



Oi Oi t^ 1^ kO Oft 



I s--" 



S§e4 04 

•* 00 -J« w 

CO 00 db a> 

1-f l-H fH i-H 

MM 



"^fi Oi o »o M -^ -- 

W3 Cft r* 7^ <^ p "* 

CO CO CO ^ ?o ?o J§ 

04 94 M 04 M (N 2 

04 04 04 »l 04 04 " 

II II II 



CO o 
CO A 

CO a 






04 04< 



I 7o 



Sfj 



00 00 

I I 



X 94 94 

^ Ij ^» ?4 "^ %4 
•* •*< '^ "^ »c »o 
04 04 04 04 04 04 

II II M 



s 



. ss ^ 



°o 



CO I S 94 oi O ' 00 

CO ' 6i8 IS g*:^ 



^%4 
« 00 

I I 



o ^ o o o o 

Oi Cb -^ 1-f !>• 1^ 
-*•'«+ US 40 If lO 
04 04 01 74 O) 04 

II II M 



■S;f 



f^ t^ o 



§1(0 £< 



11-1^ 1^ fH C4 Ol 



I I 



04 0^ 04 ^ Ud lO 

II II I II I 



^ - 

•c s 



kAiOOI^O e004Ot»'^ cc^o 
cooooo |«O00t*g t^ -t^ 



XQ 04U3gOlOiOXO^ 

> CO ^ Ud 00 40 00 Tt* lO r-l 



«00 30 00 ' 



I I 



I I 



CO- 

0404040404040404 " 

M I M II I 



00 O 

O t* CO ^ ^ lo t^ 

»3 CO t* CO IQ 00 • Oi 

82ISI ipii ;. s,5 

'i'eo o o ?82o4 

® I I 



»f5 1^ 

ss 



rH f-« 
I I 



I I 



S2 88 g 

M 04 04 04 

II II 






P?KfS 



o 

• I 
n •§ 



Is 



O JZ5 



;5 



O 
6* 






33 " 



364 Prof . J. Dewar. 

and temperature within the limits we are considering is unknown, and 
no thermometer of this kind can be relied on for giving aocnnto 
temperatures up to and below the boiling point of hydrogen. Hie 
curves are discussed in the paper, and I am indebted to Mr. J. H. D. 
Dickson and Mr. J. E. Petavel for help in this part of the work. 

Helium separated from the gas of the Song's Well, Bath, and 
purified by passing through a U-tube immersed in liquid hydrogen, 
was filled directly into the ordinary form of Cailletet gas receiver used 
with his apparatus, and subjected to a pressure of 80 atmospheres^ 
while a portion of the narrow part of the glass tube was immersed in 
liquid hydrogen. On sudden expansion from this pressure to atmo- 
spheric pressure a mist from the production of some solid body was 
clearly visible. After several compressions and expansions, the end 
of the tube contained a small amount of a solid body that passed 
directly into gas when the liquid hydrogen was removed and the 
tube kept in the vapour of hydrogen above the liquid On lowering 
the temperature of the liquid hydrogen by exhaustion to its melting 
point, which is about 16*" absolute, and repeating the expansions on 
the gas from which the solid had separated by the previous expansions 
at the boiling point, or 20'' '5, no mist teas seen. From this it appears 
the mist was caused by some other material than helium, in all 
probability neon, and M'hen the latter is removed no mist is seen» 
when the gas is expanded from 80 to 100 atmospheres, even althou^ 
the tube is surrounded with solid hydrogen. From experiments made 
on hydrogen that had been similarly purified like the helium and used 
in the same apparatus, it appears a mist can be seen in hydrogen (under 
the same conditions of expansion as applied to the helium sample of 
gas) when the initial temperature of the expanding gas was twice the 
critical temperature, but it was not visible when the initial tempera- 
ture was about two and a-half times the critical temperature. This 
experience applied to interpret the helium experiments, would make 
the critical temperature of the gas imder 9° absolute. 

Olszewski in his experiments expanded helium from about seven 
times the critical temperature under a pressure of 125 atmospheres. 
If the temperatiu*e is calculated from the adiabatic expansion, starting 
at 21° absolute, an effective expansion of only 20 to 1 would reach 
6''3, and 10 to 1 of 8''-3. It is now safe to say, helium has been really 
cooled to 9° or 10"* absolute without any appearance of liquefaction. 
There is one point, however, that must be considered, and that is the 
small ref ractivity of heliiun as compared to hydrogen, which, as Lord 
Bayleigh has shown, is not more than one-fourth the latter gas. Now 
as the liquid refractivities are substantially in the same ratio as the 
gaseous refractiWties in the case of hydrogen and oxygen, and the 
refractive index of liquid hydrogen is about 1*12, then the value for 
liquid helium should be about 1*03, both taken at their respective 



Tlie Nadir of Temperature, aiid Allied Problems, 365 

boiling points. In other words, liquid helium at its boiling point 
would have a refractive index of about the same value as liquid 
hydrogen at its critical point, and as a consequence, small drops of 
liquid hcliiun forming in the gas near its critical point would be far 
more difficult to see than in the case of hydrogen similarly situated. 

The hope of being able to liquefy helium, which would appear to have 
a boiling point of about 5° absolute, or one-fourth that of liquid hydrogen, 
is dependent on subjecting helium to the same process that succeeds with 
hydrogen ; only instead of using liquid air under exhaustion as the 
primary cooling agent, liquid hydrogen under exhaustion must be em- 
ployed, and the resulting liquid collected in vacuum vessels surrounded 
with liquid hydrogen The following table embodies the results of 
experience and theory : — 



Initial temperature. 



Liquid helium ? . . . 

Solid hjdrogea 

Liquid „ 

Exhausted liquid air. 

52° 

Low red heat 



Initial i Critical 
temperature, temperature. 



b? 

15 

20 

76 
325 
760 




6 

8 

80 

ISO 

304 



1? 

4 

5 (He ?) 
20(H) 
86 (Air) 
195 (COj) 



The first column gives the initial temperature before continuous 
expansion through a regenerator, the second the critical point of the 
gas that can be liquefied under such conditions, and the third the 
boiling point of the resulting liquid. It will be seen that by the use 
of liquid or solid hydrogen as a cooling agent we ought to be able to 
liquefy a body having a critical point of about 6° to 8** absolute and 
boiling point of about 4° or 5** absolute. Then, if liquid helium could 
be produced with the probable boiling point of 5* absolute, this sub- 
stance would not enable us to reach the zero of temperature ; another 
gas must be foiuid that is as much more volatile than heliiun as it is 
than hydrogen in order to reach within T of the zero of temperature. 
If the helium group comprises a substance having the atomic weight 2, 
or half that of helium, such a gas would bring us nearer the desired 
goal. In the meantime the production of liquid helium is a difficult 
and expensive enough problem to occupy the scientific world for many 
a day. 

A number of miscellaneous observations have been made in the 
course of this inquiry, among which the following may be mentioned. 
Thus the great increase of phosphorescence in the case of orgaiiie 
bodies cooled to the boiling point of hydrogen under light stimula- 
tion is very marked, when compared with the «&TCk!b ^^<^\i& \»t^\^gc^ 



366 MBeHng of June 20, 1901, ami Lid cf Jh$pm rmd. 



about by the ose of liquid air. A body like milplude of 
to 21"* absolute and exposed to light shows hrilliant phoqibo 
on the temperature being allowed to rise. Bodies like mdmm that 
exhibit self-luminosity in the dark, cooled in liquid hydrogen maintaiin 
their luminosity unimpaired. Photographic action is still active 
although it is reduced to about half the intensity it bears at the 
temperature of liquid air. Some crystals when placed in I^uid hydro- 
gen become for a time self-luminous, on account of the hig^ electric 
stimulation brought about by the cooling causing actual electric dia- 
charges between the crystal molecules. This is very marked wi^ 
some platino-cyanides and nitrate of uranium. Even cooling 8ii9i»^ 
crystals to the temperature of liquid air is sufficient to develop marked 
electrical and luminoii? effects. 

Considering that both liquid hydrogen and air are highly inaa- 
lating liquids, the fa^ of electric discharges taking place under such 
conditions proves that the electric potential generated by the cooling 
must be very high. When the cooled crystal is taken out of either 
liquid and allowed to increase in temperature, the luminosity and 
electric discharges take place again during the return to the normal 
temperature. A crystal of nitrate of uranium gets so highly charged 
electrically that, although its density is 2*8 and that of liquid air 
about 1, it refuses to sink, sticking to the side of the vacuum vessel 
and requiring a marked pull on a silk thread, to which it is attached, 
to displace it. Such a crystal rapidly removes cloudiness from liquid 
air by attracting all the suspended particles on to its surface. The 
study of pyro-electricity at low temperatures will solve some very 
important problems. 

During this inquiry I have had the hearty co-operation of Mr. 
Eobert Lennox, to whom my thanks are due, and Mr. J. W. Heath 
has also given valuable assistance. 



June 20, 1901. 

Sir WILLIAM HUGGINS, K.C.B., D.C.L., President, in the Chair. 

Professor William Schlich and Professor Arthur Smithells were 
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 : — 



Meeting of June 20, 1901, and List of Papers read, 367 

I. " On the Mathematical Theory of Errors of Judgment, with 
Special Eeference to the Personal Equation." By Professor 
Karl Pearson, F.RS. 

II. " Mathematical Contributions to the Theory of Evolution. 
X. — Supplement to a Memoir on Skew Variation." By 
Professor Karl Pearson, F.E.S. 

III. " On the Application of Maxwell's Curves to Three-colour 

Work, with Especial Reference to the Nature of the Inks 
to be employed, and to the Determination of the Suitable 
Light^filters." By Dr. E. S. Clay. Communicated by 
Sir W. Abney, K.C.B., F.RS. 

IV. " The Nature and Origin of the Poison of Lotus Arahicus" By 

^y. R. Dunstan, F.R.S., and T. A. Henry. 

V. '* On the Structure and Affinities of Dipteris, with Notes on 
the Geological History of the Dipteridinae." By A. C. 
Seward, F.R.S., and Miss E. Dale. 

VI. "Further Observations on Nova Persei. No. 3." By Sir 
Norman Lockyer, K.C.B., F.RS. 

VII. "Total Eclipse of the Sun, May 28, 1900: Account of the 
Observations made by the Solar Physics Observatory 
Eclipse Expedition and the Officers and Men of H.M.S. 
* Theseus,' at Santa Pola, Spain." By Sir Norman Lockyer, 
K.C.B., F.R.S. 

VIII. " The Mechanism of the Electric Arc." By Mrs. H. Ayrton. 
Communicated by Professor Perry, F.R.S. 

IX. "The Yellow Colouring Matters accompanying Chlorophyll 
and their Spectroscopic Relations. Part 2." By C. A. 
ScHUNCK. Communicated by E. Schunck, F.R.S. 

X. " Magnetic Observations in Egypt, 1883^1901." By Captain 
H. G. Lyons. Communicated by Professor Rucker, F.RS. 

XL " A Determination of the Value of the Earth's Magnetic Field 
in International Units, and a Comparison of the Results 
with the Value given by the Kew Observatory Standard 
Instruments." By W. Watson, F.R.S. 

XII. "Virulence of Desiccated Tubercular Sputum." By H. 
SwiTHiNBANK. Communicated by Sir H. Crichton 
Browne, F.R.S. 

XIII. " The Effect of the Temperature of Liqmd Air upon the 
Vitality and Virulence of the Bacillus tuberculosis" By 
H. SwiTHiNBANK. Commiuiicated by Sir H. Crichton 
Browne, F.RS. 



368 Meding qf Jwm 20^ 1901, wnd Lid qf Papen ruO. 

XIY. '' The Fermentation of Urea : a Ck>ntribation to tbe Study of 
the Chemistry of the Metabolism in Bacteria.'' By Dr. 
W. R Adeney. Commmncated by P^feasor W. N. 
Hartley, r.R.S. 

XY. " On the Seasonal Variation of Atmospheric Temperature in 
the British Isles and its Belation to Wind-direction, with a 
Note on the Effect of Sea Temperature on the Seasonal 
Variation of Air Temperature." By W. N. Shaw, F.BJ3., 
and R Walby Cohen. 

XVI. '< On the Continuity of Effect of Light and Electric Badiation 
on Matter." By Professor J. C. BosE. Communicated by 
Lord Rayleioh, F.R.S. 

XVII. "On the Similarities between Badiation and Mechanical 
Strains." By Professor J. C. BosE. Communicated by 
Lord Rayleigh, F.RS. 

XVIII. " On the Strain Theory of Photographic Action." By J. 0. 
BosE. Communicated by Lord Ra^yleigh, F.R.S. 

XIX. "The Anomalous Dispersion of Sodium Vapour." By Pro- 
fessor R. W. Wood. Communicated by Professor C. V. 
Boys, F.R.S. 

XX. " The Pharmacology of Pseudaconitine and Japaconitine con- 
sidered in Relation to that of Aconitine." By Professor 
J. T. Cash, F.R.S., and Professor W. R. Dunstan, F.RS. 

XXI. " The Pharmacology of Pyraconitine and Methylbenzaconine 
considered in Relation to that of Aconitine." By Professor 
J. T. Cash, F.R.S., and Professor W. R. Dunstan, FJLS. 

XXII. " On the Separation of the Least Volatile Gases of Atmo- 
spheric Air, and their Spectra." By Professor LiVEiNG, 
F.R.S., and Professor Dewar, F.R.S. 

XXIII. " The Stability of a Spherical Nebula." By J. H. Jeans. 

Commimicatod by Professor G. H. Darwin, F.R.S. 

XXIV. " On the Behaviour of Oxy-hsemoglobin, Carbonic Oxide Hssmo- 

globin, Methsemoglobin, and certain of their DerivatiYes, 
in the Magnetic Field, with a Preliminary Note on the 
Electrolysis of the Haemoglobin Compounds." By Professor 
Gamgee, F.RS. 

XXV. " On the Resistance and Electromotive Forces of the Electric 
Arc." By W. Duddell. Commimicated by Professor 
Ayrton, F.RS. 



On the Mathemutical Theoiy of Erroi*8 of Jv/dgmenit. 369 

XXVI. " On the Eelation between the Electrical Resistances of Pure 
Metals and their Molecular Constants." By W. Williams. 
Communicated by Professor Andrew Gray, F.R.S. 

The Society adjourned over the Long Vacation to Thursday, 
November 21, 1901, 



" On the Mathematical Theory of Errors of Judgment, with 
Special Reference to the Personal Equation." By Karl 
Pearson, F.R.S., University College, London. Received April 
23,— Read June 20, 1901. 

(Abstract.) 

In 1896 I, with Dr. Alice Lee and Mr. G. A. Yule, made a series 
of experiments on the bisection of lines at sight. The object of these 
experiments was to test a development of the cmrent theory of errors 
of observation, by which it seemed possible to me to determine the 
absoliUe steadiness of judgment of any individual by comparing, the 
relative observations of three (instead of as usual two) observers. As 
a rule the absolute error of the observer is unknown and unknowable, 
and I was seeking for a quantitative test of steadiness in judgment to 
be based on relative judgments. If o-qi be the standard deviation 
of the absolute judgments of the first observer, 0-12, o-gs, 0-31 the 
standard deviations of the relative judgments of the first and second, 
the second and third, and the third and first observers respectively, 
then 

cror = H^2i*^ + ^i8'-^28-) (i) 

on the basis of the current theory of errors. Thus it seemed possible 
to determine absolute steadiness of judgment from the standard devia- 
tions of rehitive judgments, which are all that the physicist or astro- 
nomer can usually make, provided three observers and not two were 
compared. 

To my great surprise I found results such as (i) were not even 
approximately tnie, and that they failed to hold because the judg- 
ments of the observers "were substantially correlated. It did not occur 
to me at first that judgments made as to the midpoints of lines by 
experimenters, in the same room it is true, but not necessarily bisect- 
ing the same line at the same instant, could bo psychologically corre- 
lated, and I looked about for a source of correlation in the treatment 
of the data. We had taken 500 lines of different lengths and bisected 
them at sight ; assuming that the error would be more or less propor- 
tional to the length of the line, I had adopted the deviatvoxv ix^OTSL \ioL^ 



370 Prof. Karl Pearson. 

true midpoint to the right in terms of the length of the line as the 
error. I was then led to realise the importance of what I have termed 
*' spurious correlation " in this use of indices or ratios, and I published 
a short notice of the subject in the * Boy. Soc. Proc./ voL 60, p. 489, 
1896. 

It seemed necessary accordingly to make our judgments in a diflbrent 
manner, and a second series of 520 experiments was made by Dr. Alice 
Lee, Dr. W. F. Macdonell, and myself, in which we observed the motion 
of a narrow beam of light down a imiform strip of fixed length, and 
recorded its position at the instant, h priari unknown to us, at which a 
hammer struck a small bell. The experiment was made by means 
of a pendulum devised by Mr. Horace Darwin, and the record 
required a combination of ear, eye, and hand judgment. In the 
manipulation of the data there was no room for the appearance of 
'' spurious correlation," but to my great surprise I again found sub- 
stantial correlation in two out of the three cases of what one might 
reasonably suppose to be absolutely independent judgments. 

This led to a thorough reinvestigation of the bisection experiments, 
absolute and not ratio errors being now dealt with. We found the 
same result, t.^., correlation of apparently independent judgments. 
The absolute personal equations based on the average of twenty-five to 
thirty experimental sets were then plotted, and found to fluctuate in 
sympathy, and these fluctuations were themselves far beyond the order 
of the probable errors of random sampling. Nor were the fluctuations 
explicable solely by likeness of environment. For in the bright line 
experiments while the judgments of A and B were sensibly uncorrelated, 
those of C were substantially correlated with those of both A and B. 
Thus we were forced to the conclusion that judgment depends in the 
main upon some few rather than upon many personal characteristics, and 
that while A and B had practically no common characteristics, there 
were some common to A and C and others common to B and C. We 
are driven to infer — 

(i.) That the fluctuations in personal equation are not of the order 
of the probable deviations due to random sampling. 

(ii.) That these fluctuations in the case of different observers, record- 
ing absolutely independently, are sympathetic, being due to the influ- 
ence of the immediate atmosphere of the observation or experiment on 
personal characteristics, probably few in number, one or more of which 
may be common to each pair of observers. 

In this way we grasp how the judgments of " independent '* observers 
may be foimd to be substantially correlated. In the memoir attention 
is drawn to the great importance of this, not only for the weighting of 
combined observations, but also for the problem of the stress to be 
laid on the testimony of apparently independent witnesses to the same 
phenomenon. 



On the Mathemdtical Theory of Errors of Judgment. 371 

The current theory of the personal equation thus appears to need 
modification, and we require for the true consideration of relative 
judgments not only a knowledge of the variability of observers, but 
also of their correlation in judgment as necessary supplements to the 
simple personal equation. 

Having obtained from our data twelve series of errors of observation 
considerably longer than those often or even exceptionally dealt with 
by observers, we had a good opportunity for testing the applicability of 
the current theory of errors, in particular the fitness of the Gaussian 
curve 

to describe the frequency of errors of observation. In a considerable 
proportion of the cases this curve was found to be quite inapplicable. 
Errors in excess and defect of equal magnitude were not equally 
frequent ; skewness of distribution, sensible deviation of the mode from 
the mean, "crowding round the mean," even in the case of passable 
symmetry, all existed to such an extent as to make the odds against 
the error distributions being random samples from material following 
the Gaussian law of distribution enormous. It is clear that deviation 
of the mode from the mean, and the independence of at least the first 
four error moments, must be features of any theory which endeavours 
to describe the frequency of errors of observation or of judgment 
within the limits allowable by the theory of random sampling. The 
results reached will serve to still further emphasise the conclusions I 
have before expressed : 

(a.) That the current theory of errors has been based too exclusively 
on mathematical axioms, and not tested sufficiently at each stage by 
comparison with actual observations or experiments. 

(h.) That the authority of great names — Gauss, Laplace, Poisson — 
hiis given it an almost sacrosanct character, so that we find it in current 
ase by physicists, astronomers, and writers on the kinetic theory of 
gases, often without a question as to its fitness to represent all sorts of 
observations (and even insensible phenomena !) with a high degree of 
accuracy. 

{c.) That the fundamental requisites of an extended theory are that 
it must — 

(i.) Start from the three basal axioms of the Gaussian theory and 
enlarge and widen them. 

(ii.) Provide a systematic method of fitting theoretical frequencies 
to observed distributions with (a) as few constants as possible, {p) these 
constants easily determinable and closely related to the physical charac- 
ters of the distribution, and 

(iii.) When improbable isolated observations are rejected, give thei> 
retical frequencies not differing from the observed frequencies by moid 
than the probable deviations due to random sampling^* 



372 Mathematical Ccntrihutians ta the Theory ofBvolviikm. 

I propose to consider these points in reference to tlie skew freqnonqf 
distributions discussed in a memoir in the ^Fhil. Trans.' far 18116 (A, 
vol. 186, d seq.) in another place. The present memoir, however, 
shows that these skew distributions give results immensely'more pro- 
bable than the Gaussian curve, and thus confirms in the case of errras 
of observation the results already reached in the case of oiganic 
variation. 



•"Mathematical Contributiona to the Theory of Evolution. — ^X. 
Supplement to a Memoir on Skew Variation." By Karl 
Peakson, F.RS., University College, London. Beceived May 
22,— Bead June 20, 1901. 

(Abstract.) 

In the second memoir of this series a system of curves suitable for 
-describing skew distributions of frequency was deduced from the sola- 
tions of the differential equation 

2.^.y^ ^o+A« /.v 

These solutions were found to cover satisfactorily a very wide range 
-of frequency distributions of all degrees of skewness. Two forms of 
solution of this differential equation, depending upon certain relations 
among its constants, had, however, escaped observation, for the simple 
reason that all the distributions of actual frequency I had at that time 
met with fell into one or other of the four t}T)es dealt with in that 
memoir. A little later the investigation of frequency in various cases 
of botanical variation showed that none of the four types were suit- 
able, and led me to the discovery that I had not found all the possible 
solutions of the differential equation above given. Two new types 
vrere found to exist — 

TypeV: y^y^Pe-y' (ii), 

-with a range from a; = to i; = qo , and 

Type VI: y = i^o (•«-«) ■*'-^~"*^ (iu)i 

with a range from x = a to x = oo . 

These curves were found to be exactly those required in the cases 
which my co-workers and I in England, and one or two biologists in 
America, had discovered led in the earlier Types I and lY to impossible 
results, i.e., to imaginary values of the constants. 

In the present memoir the six types are arranged in their natural 
order, and a criterion given for distinguishing between them. They 
are illustrated by three examples : (^r) age of bride on marriage for a 



On the Stnicture and Affinities of Dipterin. 373 

given age of husband ; {b) frequency of incidence of scarlet fever at 
different ages ; and (c) frequency of " lips " in the Medusa P. periiaUu 

It is perhaps of some philosophical interest to note that solutions of 
(i) that had escaped the analytical investigation were first obtained 
from actual statistics which could not be fitted to any of the curves of 
my first memoir without imaginary values of the constants. So great 
was my confidence in (i), however, that before I discarded it I re- 
investigated my analysis of it, and was so led to these two additional 
solutions. 



" On the Structure and Affinities of Bipteris, with Notes on the 
Geological History of the Dipteridinse." By A. C. Seward, 
F.R.S., University Lecturer in Botany, Cambridge, and 
Elizabeth Dale, Pfeiflfer Student, Girton College, Cambridge. 
Eeceived May 21,— Read June 20, 1901. 

(Abstract.) 

The generic name Dipteris instituted by Reinwardt in 1828 is applied 
to four recent species — Dipteris canjugata (Rein.), D, JFallichii (Hook, 
and Grev.), D, Lobbiana (Hook.), and JD, quinquefurcata (Baker). Dip- 
teris Wallichii occurs in the sub-tropical region of Northern India ; the 
other species are met with in the Malay Peninsula, Java, New Guinea, 
Borneo, and elsewhere. It has been customary to include Dipteris in 
the Polypodiacese, and to describe the sporangia as having an incom- 
plete vertical annulus. The authors regard Dipteris as a generic type 
which should be separated from the Polypodiaceae and placed in a 
family of its own — the DipteridinaB, on the grounds that (1) the 
sporangia of Dipteris have a more or less oblique annulus ; (2) the 
fronds possess well marked and distinctive characteristics ; (3) the 
vjuscular tissue of the stem is tubular (siphonostelic), and not of the 
usual Polypodiaceous type. 

For the material from Borneo and the Malay Peninsula, on which 
the anatomical investigation of Dipteris conjugatii is based, the authors 
are indebted to Mr. R Shelford, of Sarawak, and to Mr. Yapp, of 
Caius College, Cambridge. The fronds of the four species of Dipteris 
consist of a long and slender petiole and a large lamina, in some cases 
50 cm. in length; in D, conjugata and D, IVaUichii the lamina is 
divided l)y a deep median sinus into two symmetrical halves, but in 
D. Lobbiana and D, quinquefurcata the symmetrical bisection of the 
lamina is less obvious, the whole leaf being deeply dissected into narrow 
linear segments. The sori, which are without an indusium, consist 
of numerous sporangia and filamentous paraphyses, terminating in 
glandular cells. The sporangia are characterised by the T3CL"at^ ^^ Vsss* 



374 Messrs- W. R Danstan and T. A. Henry. 



Tb^ 



oblique annulua, and hy the small output of bil literal spores, 
aporangia of the sjitne sonis ara not developed simidtaneously. 

Jntfti/mtf. — The horizoutal creeping rhizome, which h thickly covered 
with stiff ramentHl sculos, contains a tubular stele limited both iii- 
terually and externally by a definite endodermis. The xylem is 
mesareh in structure ; the protoxylem groups of spiral tracheids occur 
in association with a lew parenchymatous cells at regular intenrala in 
a median position. At the point oi origin of each leaf the lubidar 
stele opens, and becomes U-shaped in section, the detached portion 
passes into the petiole as a horseshoe-shaped meristele of endareh 
structure. The meristele alters its form a short distanice below the 
origin of the lamina, and becomes constricted into two slightly unequal 
portions ; from the lower end of one of these a small yaacnlar ntnoid 
is gradually detached, and at a hi^er level a similar strand pnosm off 
from the other half of the stele. During their passage into the main 
ribs of the lamina the vascular strands, which are at first simj^y curved, 
become annular, and assume the form characteristic of MtmOki, The 
slender and branched roots are traversed by a tnarch stele. 

Geological History, — The genus Dipteris represents a type which had 
descended from the Mesozoic period with but little modification. The 
genera Dictyophyllum and Protorhipis are regarded as members of the 
Dipteridinae, which were widely distributed in Europe during the 
Rhsetic and Jurassic periods. Records of these fossil forms have been 
obtained from England, Germany, France, Belgium, Austria, Switzer- 
land, Bornholm, Greenland, and Poland; also from North America, 
Persia, and the Far East. The genus Matoniay especially M, pedinaia 
(R Br.), possesses certain features in common with Dipteris^ and this 
resemblance extends to the fossil types of the Matonineae and Dipteri- 
dinae. Matonia pedinata and Dipteris conjugata, growing side by aide 
on the slopes of Mount Ophir in the Malay Peninsula, survive as 
remnants from a bygone age when closely allied ferns played a 
prominent part in the vegetation of northern regions. 



"The Nature and Origin of the Poison of Lotus arabicus." By 
Wyndham R. Dunstan, M.A., F.R.S., Director of the Scien- 
tific and Technical Department of the Imperial Institute, and 
T. A. Henry, B.Sc, Salters' Company's Research Fellow in 
the Laboratories of the Imperial Institute. Received May 30, 
—Read June 20, 1901. 

(Abstract.) 

The authors have already given a preliminary account* of this 
investigation and have shown that the poisonous property of this 
• • Boy. fioo. Proc./ toL 67, p. 224, 1900. 



The Nature aiid Origin of the Poison of Lotus arabiciis. 375 

Egyptian vetch is due to the prussic acid which is formed when the 
plant is crushed with water, owing to the hydrolytic action of an 
enzyme, lotasey on a glucoside, lotusin, which is broken up into hydro- 
cyanic acid, dextrose, and lotoflavin, a yellow colouring matter. 

The authors have continued the investigation with the object of 
ascertaining the properties and chemical constitution of lotoflavin and 
of lotosin, and also of studying the properties of lotase in relation to 
those of other hydrolytic enzymes. 

Lotusin, 

Lotusin can be separated from an alcoholic extract of the plant 
by a tedious process giving a very small yield, about 0*025 per cent. 

Lotusin is a yellow crystalline glucoside, more soluble in alcohol 
than in water. When heated it gradually decomposes without 
exhibiting any fixed melting point. Combustions of specially purified 
material gave numbers agreeing with those deduced from the formula 
C28H31NO16. 

In the preliminary notice the formula C22H19NO10 was provisionally 
assigned to lotusin on the assumption that one molecule of dextrose is 
formed by its hydrolysis. The formula given above, as the result of 
ultimate analysis, is confirmed by the observation that two molecules 
of dextrose are produced by acid hydrolysis, which is therefore repre- 
sented by the equation — 

C28H3iNOio + 2H.,0 = 2CoHi20a + HCN + Ci,HioOo. 
Lotusin. Dextrose. FruMic Lotoflarin. 

acid. 

When a solution of lotusin is warmed with dilute hydrochloric acid, 
hydrolysis readily occurs. The liquid acquires a strong odour of 
hydrocyanic acid and a yellow crystalline precipitate of lotoflavin u 
thrown down, whilst the solution strongly reduces Fehling's solution. 
Dilute sulphuric acid only very slowly effects the hydrolysis of 
lotusin. 

When warmed with aqueous alkalis, lotusin is gradually decomposed, 
ammonia being evolved and an acid formed to which the name lotusinic 
arid has been given. 

C28H81O16 + 2H2O = C28H82O18 + NHS. 

Lotusinic acid is a monobasic acid furnishing yellow crystalline 
salts. It is readily hydrolysed by dilute acids forming lotoflavin, 
dextrose and heptogluconic acid (dextrose-carboxylic acid) : 



C28H82O18 + 2H2O = CisHioOa + CeHiaOe + CrHuOs. 

Lotusinic Lotoflayin. Dextrose. Heptogluconic 

acid. %aI^, 

VOL LXVIIL *! ^ 



376 MeeuBia W. R Dnnstan and T. A. Heniy. 

With the exception of amygdalin, lotcuin is the only glnooeide 
definitely known which furnishes prussic acid as a decomposition 
product. 

Lotoflavin. 

Lotoflavin is a yellow crystalline colouring matter readily diasolyed 
by alcohol or by hot glacial acetic acid, and also by aqueous alkalis 
forming bright yellow solutions. It is always present to some extent 
in the plants, especially in old plants. Ultimate analysis leads to the 
formula dsHioOo. It is therefore isomeric with luteolin, the yellow 
colouring matter ol Reseda luieoUij and with JiseHnj the yellow colouring 
from young fustic, Bhus eoHnus. Morin, from Moms Hndaria^ appears to 
be hydroxylotoflavin. 

Lotoflavin does not form' compounds with mineral acids. It 
furnishes a tetracetyl derivative and two isomeric mutually con- 
vertible trimethyl ethers which are capable of forming one and the 
same acetyl-trimethyl-lotoflavin. By the action of fused potash loto- 
flavin is converted into phloroglucin and jS-resorcylic acid. 

Dextrose. 

The sugar resulting from hydrolysis has been found to correspond 
in all properties with ordinary dextrose. 

Hydrocyanic acid. 

The amount of prussic acid given by plants at diflerent stages of 
growth has been ascertained. Mature plants bearing seed-pods have 
fumished 0*345 per cent, of this acid, calculated on the air-dried 
material which corresponds with 5*23 per cent, of lotusin. Younger 
plants bearing flower buds gave 0*25 iper cent., whilst still smaller 
quantities were furnished by very young plants and hardly any by quite 
old plants from which the seeds had fallen. 

The formation of the poison, therefore, seems to reach its maximum 
at aix)ut the seeding period, and after this period to diminish rapidly. 
The Arabs are aware that the plant is safe to use as a fodder when the 
seeds are quite ripe, but not before. We have found that it is the 
lotusin which disappears during the ripening of the seeds. Old plants 
contain some lotase and lotoflavin, but little or no lotusin. 

Lotase. 

In its general properties lotase resembles other hydrolytic enzymes^ 
from which, however, it differs in several important respects. It may 
be compared with emulsin, the enzyme of bitter almonds. £mul8in» 
however, only attacks lotusin very slowly, whilst lotase has but a feeble 



The Nature and Origin of the Poison of Lotus arabicus. 377 

action on amygdalin, the glucoside of bitter almonds. Lotase is much 
more readily injured and deprived of its hydrolytic power than 
emulsin. On this account it is difficult to isolate in the solid state. 
Its power is not only rapidly abolished by heat, but is also gradually 
destroyed by contact with alcohol or glycerine. Besides lotase, the 
plant contains an amylolytic and a proteolytic enzyme. 

Constitution of Lotofiavin and Lotusin, 

Having regard to its reactions and especially to the production, 
by the action of fused alkali, of )8-resorcylic acid and phloroglucin, 
the authors conclude that lotofiavin should be represented by the 
formula : 

OH 



'm-<=>' 




OH 00 

which is that of a compound belonging to the same class, of phenylated 
pheno-y-pyrones, as its Isomerides luteolin and fisetin. The peculiarity 
shown by lotofiavin of containing four hydroxyl groups, but furnishing 
only a /rimethyl ether, is accounted for by one of the hydroxyl groups 
being in the ortho position to a carbonyl group. 

The reactions of lotusin are best represented by the formula : 

CnHjjOio— OH— O /\ 

OH CO 

which is that of a lotofiavin ether of maltose-cyanhydrin. 

This formula satisfactorily accounts for the partial hydrolysis of the 
glucoside by alkalis giving lotusinic acid and ammonia, and for the 
decomposition of the substance by acids giving lotofiavin and maltose- 
carboxylic acid which is immediately decomposed into dextrose and 
heptogluconic acid. It also accounts for the hydrolysis of lotusin, 
by acids, into lotofiavin and maltose, which is further changed to 
dextrose. 

In order to definitely localise the position of the cyanogen group in 
lotusin, the behaviour of several cyanhydrins of known constitution 
have been examined with reference to the question as to whether 
they would furnish hydrocyanic acid when acted on by dilute hydro- 
chloric acid. It was foimd that mandelic nitrile, Invulose cyanhydrin 
and pentacetyl gluconitrile, in which the cyanogen group is known to 
occupy a position similar to that assumed for it in the lQ»rcsi\)\». ^x^^- 

'I T> ^ 



378 Pro! J. T. Cash and Mr. W. R DumtaiL 

gesied for lotusin, are, lilce lotusm, easily decompoeed by dilate 
hydrochloric acid, forming proBsic add and die corresponding aldehyde 

or ketone. 

The authors wish again to express thdr obligations to Mr. Ernest 
A. Floyer, of Cairo, Member of the Egyptian Institute, who has spared 
neither trouble nor expense in collecting in Egypt, and despatchhig to 
this country, the material required for this investigation. 



" The Pharmacology of Pseudaconitine and Japaconitine Considered 
in relation to that of Aconitine." By J. Theodore Cash, M.D., 
F.RS., Begins Professor of Materia Medica in the University 
of Aberdeen, and Wyndham R Dunstan, M.A., F.RS., 
Director of the Scientific Department of the Imperial Insti- 
tute. Beceived June 11 — Bead June 20, 1901. 

(Abstract.) 

In a previous paper on the Pharmacology of Aconitine and some 
of its principal derivatives,* we have given an account of the physio- 
logical action of this, the highly toxic alkaloid of Monkshood {Aconitum 
Napellus)f and of its principal derivatives, and we have also discussed 
the ascertained physiological effects of these substances in relation to 
their chemical constitution. The results of this investigation have 
proved to be of much practical importance in connection with the 
pharmaceutical and medical employment of aconite, especially in 
demonstrating the partial antagonism to aconitine of benzaconine, and 
in a greater degree of aconine, both of which derivatives accompany 
the parent alkaloid in the plant and in the pharmaceutical preparations 
made from it, which have been hitherto used medicinally. Although it 
seems likely that these separate alkaloids, and especially aconine, may 
be useful as therapeutic agents, it is now clear that for the purpose for 
which aconite is employed, the pure alkaloid, aconitine, should be used 
in the place of the indefinite mixture of physiologically antagonistic 
alkaloids contained in pharmaceutical preparations made from the 
plant. 

In a series of papers communicated to the Chemical Society, and 
published in the 'Journal of the Chemical Society' (1891-99), one of 
us, in conjunction with his pupils, has described the chemical properties 
of the toxic alkaloid contained in two other species of alkaloid, viz., 
Acomium ferox or Indian or Nepaul Aconite, and Aconitum Fischeri or 
Japanese Aconite. The medicinal employment of these potent drugs 

• ' Phil. Trans./ B, 1898, toI. 190, p. 2S9. 



jThe Pharmacology of Psetidaconitine and Japaconitine, 379 

has been very restricted in the absence of any definite knowledge as 
to the nature of their constituents and the physiological action to 
which they give rise. 

Aconitum ferox has long been known to botanists and travellers in 
India as a poisonous plant of great virulence. It is used in Indian 
medical practice under the vernacular name of "Bikh." There appear 
however to be several v^eties of aconite passing under this vernacular 
name. This is a subject which we are at present investigating with 
the assistance of the Government of India. 

In 1878 Alder Wright isolated a crystalline, highly toxic alkaloid, 
from the root of the plant, and named it pseudaconitine. In 1897* 
one of us gave an account of a complete investigation of the chemistry 
of this alkaloid, the results of which have led to a modification in 
certain important respects of the conclusions arrived at by Wright and 
his co-workers. Our results have been confirmed by Freund and 
Niederhofheim.t 

For details of the chemistry of pseudaconitine and its derivatives, 
reference must be made to the paper already referred to. J We may 
here briefly record the chief properties of the alkaloid. 

Pseudaconitine is a crystalline alkaloid whose composition differs 
from that of aconitine, being expressed by the formula C8«H49NOi2. 
The crystals melt at ^02°, and are sparingly soluble in water, but 
readily in alcohol. The salts are usually crystalline and soluble in 
water. Their solution and those of the base produce, in excessively 
minute quantities, a persistent tingling of the tongue, lips, and other 
surfaces with which they are placed in contact, in this respect re- 
sembling aconitine and its salts, which produce the same effect. 

When heated in the dry state at its melting point pseudaconitine 
evolves a molecular proportion of acetic acid, leaving another alkaloid, 
pyropseudaconitine. This alkaloid, like the corresponding pyrc^ 
derivative of aconitine, does not give rise to the characteristic tingling 
effects of the parent base. 

When a salt of pseudaconitine is heated in a closed tube with water, 
as in the case of aconitine, partial hydrolysis occurs with the loss of a 
molecule of acetic acid, an alkaloid, veratryl-pseudaconine, being left. 
This alkaloid, like the corresponding benzaconine, derived by similar 
means from aconitine, produces neither the tingling sensation nor the 
toxic effects of the parent base. 

The complete hydrolysis of pseudaconitine, which is reached when 
the above-mentioned veratryl-peeudaconine is heated with alkalis, 
produces, instead of the benzoic acid furnished by aconitine, veratric or 
dimethylprotocatechuic acid, together with a base, pseudaconine, not 

• < Proc. Chem. Soc.,' 1895, p. 154 ; * Trans. Chem. Soo.,* 1897, p. 350. 
t * Bcr./ vol. 29, pp. 6, 832. 
J Loc. cii. 



380 Piof. J. T. Cash and Mr. W. K Dunstan. 

siuoeptible of further hydrolysia. Whibt there ia thos a rtrong 
general resembhuice in chemical oonstitation between peeodaconitiiie 
and aconitine, the benzoic radical of aconitine is replaced in peead- 
aconitine by the veratric radical of veratric add, whilst tiiere are 
probably also constitutional differences in the central nudeos. 

The composition and properties of the toxic alkaloid prasent in 
Japanese aconite, ^' Kiiza-usu," regarded by. botanists as AcpmUmm 
japonieum or A, Fiteheri^ has been the subject of some dispute among 
chemists who have examined it. Wright regarded it as chenucally 
different from aconitine, both in composition and in structure, being 
an anhydro- or apo-derivative formed by the loss of water and conju- 
gation of 2 molecules of an unknown alkaloid of the aconitine type. 
He assigned to it the formula GfloHasNsOn. Liibbe afterwards studied 
the properties of japaconitine, and pronounced it to be identical with 
aconitine, and, more recently, Freund and Beck have reached the same 
conclusion. Later, one of us, in conjunction with H. M. Bead,* sub- 
jected japaconitine to a very detailed investigation, in the course of 
which its properties and those of its principal derivatives were defined 
and compared closely with those of aconitine. We believe that these 
results leave little room for doubting that japaconitine is a distinct 
alkaloid different from aconitine, although Wright was mistaken in 
the view he took of its composition and constitution. Superficially 
japaconitine bears a very strong resemblance to aconitine ; it is, how- 
ever, richer in carbon, and the physical properties of its derivatives do 
not agree with those of aconitine. To this alkaloid we have pro- 
visionally assigned the formula C84H49NO11, and have retained for it 
the name of japaconitine suggested by Wright. 

In general, the decomposition of japaconitine resembles that of 
aconitine, but the physical properties of the resulting derivatives are 
not the same. By the action of heat it furnishes acetic acid and jap- 
P3rraconitine ; on partial hydrolysis, japbenzaconine is obtained besides 
acetic acid ; whilst on complete hydrolysis, the products are acetic 
acid, benzoic acid, and japaconine. Whilst therefore the constitution 
of the central nucleus appears to be different, both aconitine and jap- 
aconitine contain the acetyl and benzoyl groups, whilst in pseudaconi- 
tine the acetyl and veratryl groups are present. 

In the present paper the physiological action of specially purified 
pseudaconitine and japaconitine is recorded and compared with aconi- 
tine. 

The differences found are nearly always differences of degree and 
not differences of kind, a result which bears out the close constitu- 
tional relationship which is to be inferred from their chemical re- 
actions. Although there are probably constitutional differences in the 
central nuclei of the three alkaloids, the same constitutional type is to 

• ' Journ. Chem. Soc.,' 1899. 



The Pharrruicoiogy of Pscudcuxniitine arid Japaconitine, 381 

be seen in each, and the substitution of a veratryl group (in pseud- 
aconitine) for an acetyl group (in aconitine) coimts for little in 
influencing the characteristic physiological action. 

In order to bring the auction of aconitine, pseudaconitine, and 
japaconitine into a contrast, which may be readily apprehended at 
a glance, the following summary will be useful. 

Heart — All three alkaloids have a similar effect upon the heart of 
such mammals as have been observed. Pseudaconitine is quantita- 
tively more energetic than the other two, towards cats, but is certainly 
not nearly twice as toxic when artificial respiration is practised. 
Towards the frog's heart pseudaconitine is slightly less powerful than 
the other two, of which japaconitine is rather the more active. 

Fa^us Nerve and Inhibitory Mechamsm in Heart. — Heart slowing from 
increased central vagus activity is produced by all these alkaloids, and 
similar results follow section and stimulation of the nerve at this and 
later stages of poisoning by one and all of them, both in mammals and 
frogs. 

Respiration. — There is less tendency to acceleration of respiration in 
mammals poisoned by pseudaconitine than when the other two alka- 
loids are employed; further, the dyspnoeal conditions develop more 
suddenly and the central depression of respiration is greater. Jap- 
aconitine is at first slightly more depressant than aconitine, but 
thereafter the tendency to acceleration of respiration is sooner 
developed, otherwise the general features of their action are similar. 

Blood. — ^All the aconitines produce a deleterious effect upon the 
haemoglobin and coloured corpuscles of the blood when they are given 
repeatedly in large doses. As far as has been ascertained this is due 
to impairment in the nutrition of the animal rather than to a direct 
action. 

Frogs kept in a watery medium or in contact with a moist surface 
develop oedema after receiving any of the aconitines, but this condition 
is most marked and the hydrsemia of the blood is more pronounced 
and lasting after pseudaconitine. 

Brain and Cord. — All aconitines appear to have a similar effect 
qualitatively on the brain and cord of rabbits, pigeons, and frogs. 

Temperature. — The initial elevation of temperature often seen in 
rabbits which have received aconitine or japaconitine is less frequently 
observed after pseudaconitine. A slightly greater and more enduring 
fall of internal temperature is witnessed after the latter, when the dose 
is large and bears a like relationship to the lethal amount. 

Repeated Administration. — Some tolerance is established on the part 
of rabbits towards all the aconitines, and this is manifested with 
reference to temperature reduction, to the cardiac effect, and, to a 
lesser extent, to respiration; the general toxicitj^ undergoing a 
reduction which is not, however, extensive. Less tolftx^TkR«k S& ^Sckss^vk. 



382 Prof. J. T. Cash and Mr. W. R Dunstan. 

towards pteudaconitine than towards the other two : it has been foimd 
impossible hitherto to determine how far rapidity of eUmination varies 
between the alkaloids. 

Senwry Nerves. — Local applications of the aconitine ointoienta of 
eqnal strengths are followed by a somewhat more powerfully, depres- 
sant and enduring effect when these contain aconitine or japaeomtme 
than pseudaconitine. This statement has reference to eutaneoiis ■enaory 
and thermic impressions in the human subject. The difEBTRnoe la at 
most but slight. 

Motor Nerve and Muscle. — ^The action of the individual aUcaloids is 
much the same whether specimens of B. esculenia or R iempomria 
are used. It is more difficult to reduce reaction or to produce 
insensitiyeness of the intramuscular motor nerves by pseudaconitine 
than by the other alkaloids. The so-called curare-Iika action has 
been found for all the alkaloids to be much feebler than was at one 
time supposed. 

Direct contact of the alkaloidal solutions with musde-nerve pre- 
parations reduces excitability, the muscle being a£kcted by solutions 
containing less than 1 in 1,000,000, and the nerve by solutions still 
weaker. Pseudaconitine is recognised as producing a rather weaker 
effect than the two other alkaloids, which are nearly equal to one 
another, japaconitine being slightly the more energetic. 

The results of the experiments detailed in this paper do not in all 
respects agree with previous observations ; especially is this the case 
with regard to the relative toxicities of the three aconitines. The 
general order of toxicity towards mammals is pseudaconitine, jap> 
aconitine, and aconitine, which is the least toxic. Pseudaconitine has 
been found (roughly speaking) twice as toxic as aconitine towards the 
small mammals and birds used in the research. This agrees closely 
with the results of Adelheim* and Bohm and £wers.t Ck>ettat 
states that pseudaconitine is the stronger alkaloid, but gives no propor- 
tion. Our results differ from those of Nothnagel and Bossbach,§ who 
state that pseudaconitine is seventeen times as active as aconitine, 
and of Hamack and Meunicke,|| who find the under margin of active 
dosage equal. Kobertll finds pseudaconitine and aconitine to be in 
activity " ziemlich gleich." 

The relative toxicity of japaconitine to aconitine is approximately 
as ten to about nine towards the small mammals and birds which were 
used. Previously japaconitine has been seldom contrasted with the 

* Adelhcim, ' Forens. Chem. Untenuoh,' Dorpat, ISeO. 

t BiShm uid Ewers, * Axeh. f. Exp. Path. ii. Pharm.,* 1878, Bd. 1, p. 885. 

X Cloetta, ' Lehbr. d. Arzneim. u. ArzneiTerordnungsl..' Freib., 18S5. 

§ Nothnagel a. Bosebach, ' Mat. Med. u. Therap.' (Fr.), 1880, 685. 

II Hamack and Meunicke, < Berl. Klin. Wchsch./ 1883, No. 48, p. 657. 

y Kobert, • Lehbr. d. Inlox.,* p. 667. 



The Pliarmacology of Psetcda^oniiine and Japaconitine, 383 

other two aconitines, but has been recognised as stronger than aconitine 
by Langaard,* and in one series of observations by Harnack and 
Meunicke. Robert, on the other hand, does not separate japaconitine 
from aconitine and pseudaconitine in toxicity. 

Dosage. — Based upon the observations made, the relative doses for 
therapeutical purposes would be approximately, regarding that for 
aconitine as the unit, for pseudaconitine 0*4 to 0'45, and for jap- 
aconitine 0*8. 

Towards frogs the toxicity of these alkaloids is by no means so 
great (per giamme body- weight) as it is towards the same unit of the 
mammals and birds included in this research. Thus the lethal dose 
per kilo, mammalian weight may only be lethal to 140 to 170 grammes 
of frog weight, or even to less, according to the time of year. A 
medium-sized rabbit may therefore be poisoned by a dose of aconitine 
or japaconitine which would suffice to destroy six or eight frogs. 

Japaconitine is slightly more toxic towards both mammals and frogs 
than is aconitine, but the higher toxicity of pseudaconitine towards 
birds and mammals is iiot associated with an equal activity towards 
frogs, for it exerts towards both K esctdenta and B. temporaria a 
slightly lower toxicity than do either of the other alkaloids 

There is no essential difference in the reaction of B, esctdenta and B, 
temporaria respectively to individual aconitines beyond a greater or less 
accentuation of one or other symptom, as for example more excited 
movement in the latter, more reduction of reflex in the former, but in 
all parallel series of observations the resistance of B. esculenta has 
proved to be slightly greater to all the aconitines examined. 

As concerns the local action of the aconitines upon sensory (cuta- 
neous) structures in man, the differences are so trifling as to be 
negligible. 

As regards the therapeutical employment of aconitine, japaconitine, 
and pseudaconitine, the great similarity in their physiological actions, 
amounting almost to a qualitative identity, which is established by this 
investigation, justifies the employment of any one for internal ad- 
ministration, provided that the dosage is properly regulated. Given in 
the proportions mentioned above, the three alkaloids would exert 
the same action. We strongly recommend the use of a pure alkaloidal 
salt in preference to preparations made from the plants, since the 
lAtter would be difficult to standardise, and even if this were done, the 
action of the aconitines would be modified to a greater or less extent 
by the other alkaloids present in the vegetable preparation. 

For local applications the three alkaloids may be introduced into 
ointments in identical proportions. The greater toxicity of pseud- 
aconitine need not prevent its use in this department of treatment if it 

• Langaard, * Arch. f. Path. Anat.,' 1880, 70, s. 229. 



384 Prof. J. T. Cash and Mr. W. R Dunatan. 

is remembered that all applications of the aconitines, aztemallj, are to 
be considered dangerous if any abrasion of the skin is presentb 

The chemical part of this inquiry has been conducted in the Labora- 
tories of the Scientific Department of the Imperial Institotei with the 
assistance and co-operation of the GfoTemment of India. Our thankB 
are specially due to Dr. G^rge Watt, C.IJL, Beporter on Bconomic 
Products to the Gtovemment of India, for the interest he has shown in 
the investigation, and for the care he has taken in the coUectioii of the 
necessary materiaL 

The physiological experiments hare been conducted in the Depart- 
ment of Materia Medica and Pharmacology of the Univenity of 
Aberdeen, and hare been assisted by a grant made by the JSoyal 
Society from the Ooremment Fund. The assistance of Drs. Esalemoni 
and IVaser has been rery valuable in carrying out some of the obaer- 
rations entailed in this department of the research. 



■" The Pliarmacology of Pyraconitine and Methylbenzaconine con- 
sidered in Belation to their Chemical Constitution." By J. 
Theodore Cash, M.D., F.E.S., Regius Professor of Materia 
Medica in the University of Aberdeen, and Wyndham R. 
DuNSTAN, M.A., F.E.S., Director of the Scientific Department 
of the Imperial Institute. Received June 11, — Read June 20, 
1901. 

(Abstract.) 

In a previous paper* we have shown that an entire change in the 
physiological action ensues on the withdrawal of the acetyl group 
from aconitine as is seen in the action of benzaconine, the first 
hydrolytic product of aconitine, from which it differs in containing 
an atom of hydrogen in the place of one acetyl group. This 
alkaloid is devoid of the characteristic physiological action and 
extraordinary toxicity of aconitine, whilst in respect of its action on 
the heart it is in the main antagonistic to that of the parent alkaloid. 
In order to study further the remarkable dependence of the physio- 
logical action on the presence of the acetyl group, we have examined 
the action of two derivatives of aconitine which we have obtained in 
this research, viz., pyraconitine and methylbenzaconine. 

Pyraconitine was first prepared by one of usf by heating aconitine 
at its melting point, when the acetyl group is expelled as one molecule 
of acetic acid and the alkaloid pyraconitine remains. This compound 

* * Phil. Trans.,' B, lb98, toI. 190, p. 239. 

t Dunstan and Carr, * Trans. Chem. Soc.,' 1894, toI. 66. p. 176. 



The Pltarmacology of Pyraconitine and Methylbenzaconine, 385 

therefore differs in composition from aconitine by the loss of one 
molecule of acetic acid, and from benzaconine by one molecule of 
water. 

Methylbenzaconine was obtained from aconitine by heating it with 
methyl alcohol in a closed tube.* A remarkable reaction takes place, 
in which the acetyl group is ejected as acetic acid, a methyl group 
taking its place. This alkaloid therefore differs from aconitine in 
containing a methyl group in the place of the acetyl group, and from 
benzaconine in containing a methyl group in the place of one atom 
of hydrogen. The examination of its physiological action would 
therefore be the means of studying the result of replacing in aconitine 
the negative radical acetyl by the positive methyl group, and also of 
studying the effect of the introduction of methyl in modif3ring the 
physiological action of benzaconine. 

The acetyl group of aconitine evidently occupies an exceptional 
position in the molecule of aconitine. So far as we are aware it is 
the only acetyl compound at present known, which exchanges this 
group for methyl when it is heated with methyl alcohol. We have 
examined the behaviour of numbers of different types of acetyl 
derivatives from this point of view and can find none analogous to 
aconitine. 

For the study of their physiological action these alkaloids have 
been specially purified and employed as hydrobromides in aqueous 
solution. 

Contrasting the physiological action of pyraconitine with that of 
aconitinfi, as described in the present paper, we find, as might be 
anticipated from our previous results, that through the removal of the 
acetyl group the great toxicity of aconitine is nearly entirely abolished 
and the characteristic features of aconitine poisoning are no longer 
produced by pyraconitine. 

Contrasting the physiological actions of benzaconine and pyr 
aconitine which differ from each other empirically by one molecule of 
water, pyraconitine, the anhydride, is the more active compound. 
Both these alkaloids, divested of the acetyl group of aconitine, are rela- 
tively weak and feebly toxic when compared with the parent alkaloid. 

Although benzaconine and pyraconine exhibit a strong similarity in 
the physiological effects they produce, there are differences between 
them which are probably more considerable than they would be if 
pyraconitine were merely the anhydride of benzaconine. 

The substitution in aconitine of methyl for acetyl which occurs in 
the formation of methyl benzaconine has led to a very considerable 
reduction in toxicity and has introduced a curare-like effect similar to 
that first oW»rvred by Grum Brown and Frasert to result from the 

• * Proo. Chexn. Soc./ 1896, p. 159. 

t * Trans. Roy. Soc. Edinb.,' 1869, toI. 25, p. 19^. 



386 Prof. J. T. Cash and Mr. W. R Dunstan. 

introducton of methyl into the molecule of an alkaloid. Methyl bena- 
aconine is however more toxic and generally more powerfol than 
benzaconine, owing to the presence of the methyl group. 



Adum of Fffrac(mUme» 

The main effects of pyraconitine may be thus snmmarised. Its 
local application is devoid of the effects characteristic of the aconi- 
tineR. Its chief action upon the heart is to cause slowing, partly 
from vagus irritation, partly from depression in function of intrinsic 
rhythmical and motor mechanisms. 

There is less tendency to want of sequence in the cardiac chamber 
walls than is observed after the aconitines and benzaconine. 

The vagus apparatus remains active in degree after doeee some- 
what in excess of the lethal, the slowed heart of pyraconitine being 
accelerated both by vagotomy and by atropine. 

Activity of respiration is reduced (by central depression) to a degree 
incompatible with life, as is the case after aconitine and benzaconine. 
llie peripheral motor nerves and muscular tissues are not at this time 
markedly affected. Artificial respiration prolongs life, but the slowed 
heart and greatly reduced blood pressure tend to a fatal issue. 

The spinal cord is impaired in its reflex fimction, apparently 
secondarily to reduced circulation in its structure. A tendency to 
tonic spasm in frogs is late in appearing and of moderate degree. It 
has not been seen after destruction of brain and medulla. It is 
further associated with a curious condition of exaggerated motility. 

Neither muscular nor intramuscular nervous tissue are strongly 
influenced by pyraconitine in lethal or somewhat hjrperlethal doses. 
The lethal dose per kilo, frog's weight is practically about twelve times 
that which is lethal per kilo, rabbit's weight. 

Contrasted Effects of Pyraconitine and Benzaconine. 

Of these two alkaloids, pyraconitine is approximately six to seven 
times more toxic towards mammals (rabbits and guinea-pigs) than 
benzaconine, and five to six times more so towards frogs. They are 
alike in their action upon mammals, in so far as they are non-irritant, 
that they slow the respiration without preliminary acceleration, that 
they slow the heart and reduce the blood pressure to a very low level, 
that they cause paresis and in guinea-pigs clonic movements, and 
that respiratory failure is the immediate cause of death. They differ 
in so far that pyraconitine acts more rapidly, but for a shorter period, 
whilst fatal termination of poisoning is preceded by convulsions, 
which are very rare after benzaconine. Benzaconine alters the 
sequence of the ventricles upon the auricles much more usually and 



Th^ Pharmacology of Pyraconitine and Methylbenzaconhie, 387 

to a greater extent than pyraconitine, though if asequence is de- 
veloped it has the same general character (the auricular second beat 
being blocked from the ventricle). 

Whilst pyraconitine stimulates the cardiac vagus both centrally and 
within the heart (section and atropine causing acceleration), and 
finally occasions only a limited reduction in its activity, benzaconine 
produces but little stimulation, and ultimately suspends the vagus 
inhibitory action. Under these conditions atropine is, of course, 
inoperative. Both accelerate the heart in small, but slow it in large, 
dose, and both may disorder the sequence, but vagus inhibition is 
much more interfered with by benzaconine. Frogs poisoned by benz- 
aconine lose the power of voluntary movement, then reflex disappears, 
and finally the circulation is arrested ; but after pyraconitine, reflex 
outlasts the heart's action. Late spasm occurs after the latter, not 
after the former. Whilst in lethal doses pjrraconitine has no effect 
beyond somewhat favouring fatigue and reducing excitability of motor 
nerves, benzaconine greatly impairs their function, and in thorough 
poisoning may suspend it entirely. 

Action of Methylhemaconine. 

The action of methylbenzaconine may be summed up as follows : It 
is very feeble in its toxicity when contrasted with aconitine, but is 
somewhat stronger than benzaconine. 

Small and medium doses, whilst slowing the heart, do not cause any 
failure in sequencoi but larger doses have this effect. They act upon the 
rhythm of the organ, involving the movement of the auricle and ven- 
tricle whilst ultimately the sequence of the latter upon the former is 
impaired, so that it follows only a certain proportion of the auricular 
** leads." This block is not removed by atropine. Whilst the passage 
of the ventricle into the diastole is at first retarded, the contractile 
power of the myocardium is ultimately reduced by methylbenzaconine. 

The cardiac vagus is depressed in action and its inhibitory function 
is ultimately suspended by large doses, neither section of the vagus 
nor atropine administration relieving the slow and faulty action of the 
organ. 

There is evidence of slight primary stimulation of reflex cord 
centres when ligature of vessels prevents the masking of this condition 
by the peripheral action of the poison. The subsequent impairment 
in cord reflexes is later in occiu'ring and of much shorter duration 
than the action of methylbenzaconine upon intramuscular motor 
nerves. 

In mammals the paralytic symptoms are predominant, the fall of 
temperature is in part attributable to this cause as well as to changes 
in the circulation. The clonic movement and salivation (observed vcl 



388 The Fharmaeoloffy of Fifracamiins and MUh^lbenmetmine. 

a certain stage of the action of methylbencaconine, espedally upon 
guinea-pigs) are suggestire of the action of a near ally of aeonitine. 
In frogs, however, there is no semblance to an aeonitine eflRsct^ xmless 
its very feeble action towards sensory nerves or its much more 
powerful action upon motor nerves, be thus viewed. Motor nerves 
are greatly affected by doses which are distinctly below the lethal for 
cold-blooded animals, the action being curare-like in character. Mus- 
cular tissue is after the action of large doses more susceptible of 
fatiguing influences. Fibrillation in muscles to which the poison has 
access is more common than after aeonitine or any other derivative 
examined. 

These observations support in the main the contention of Cmm 
Brown with Fraser that the introduction of methyl into the molecule 
of certain spasm-|nx>ducing alkaloids, marks the effect of these by 
occasioning a curare-like action at the periphery. 

Coniraiied Ejfeds of MeAylbmzaeomne and Acaniiine. 

The toxicity of aeonitine is, roughly, eighty to one hundred times 
that of methylbenzaconine towards rabbits and guinea-pigs, and much 
the same proportion holds for summer and winter frogs respectively. 
Whilst slight tendency to salivation and retching movements are pro- 
duced by methylbenzaconine, and are in so far suggestive of a slight 
aeonitine action, the absence of initial acceleration of respiration, of 
local irritation, and dyspnceal convulsions, and the predominance of 
paralytic symptoms, are points of difference. The action upon the 
heart is entirely distinct, for the pulse is slowed by methylbenz- 
aconine, the auricles eventually beating more rapidly than the ventri- 
cles, the action of the poison proceeds uniformly and without the 
intermissions which characterises aeonitine, whilst the early phenomena 
of vagus stimulation have little in common. The general symptoms 
of poisoning in frogs have scarcely a point of similarity, quiescence, 
rapid failure of reflex, and voluntary movement, without impairment 
of the cardiac action, are distinctive of methylbenzaconine, whilst 
excitement with great motility and persistence of voluntary move- 
ment follow aeonitine. Fibrillation is much more pronounced after 
the former, though it is only a transitory phenomenon. The action 
on the heart differs widely in frogs as it does in mammals, whilst the 
curare-like action of the derivative on motor nerves is not produced by 
aeonitine in doses which just suffice to arrest the heart. 

It is true that large but sublethal doses of aeonitine are followed by- 
a condition of almost complete paralysis, which lasts for several days, 
but during this time there is slight voluntary and reflex movement, the 
nerve-endings are not put out of action, and the circulation is usually 
of the feeblest character, all conditions which are not found in tbe 
eriod of quiescence following methylbenzaconine. 



Separation of the Least Volatile Gases of AivnospJieric Air, &c, 389 

Contrasted Effects of Methylhenzaconine and Bemaconine, 

Methylbenzaconine is from three to four timea more toxic towards 
rabbits and guinea-pigs than benzaconine, and from twice to thrice as 
toxic towards frogs (B. temp, and B, esc,). In mammals, slight saliva- 
tion, retching movements, and muscular tremor are characteristic 
eifects of the former, but dyspncea, ataxia, and paresis are also seen 
after benzaconine. Of the two, methylbenzaconine is distinctly less 
depressant towards the heart. Slowing of the pulse and want of 
sequence of ventricular upon auricular action occurs after both, but is 
a much earlier symptom after benzaconine, which causes more dis- 
order in the motor mechanism. On the other hand, the intracardiac 
vagus is put out of function more readily by methylbenzaconine. 
Death after either poison is rarely preceded by spasm. Neither of the 
two compounds cause any local irritation in frogs, but methylbenz- 
aconine produces active fibrillation in the muscles, to which it gains 
access and develops a complete curare-like action much more promi- 
nently than does benzaconine, the heart continuing to beat strongly. 
Benzaconine, in dose sufficient to cause such an effect at the periphery, 
acts disastrously upon the circulation. In partial poisoning by 
methylbenzaconine the characteristic rapid failure of the intramuscular 
motor nerves on stimulation is well marked, but the subsequent 
recovery on resting, so characteristic of benzaconine, has not been 
observed. 



" On the Separation of the Least Volatile Gases of Atmospheric 
Air, and their Spectra," By G. D. Liveing, M.A., ScD., 
F.RS., Professor of Chemistry in the University of Cam- 
bridge, and James Dewar, M.A., LL.D., F.RS., Jacksonian 
Professor in the University of Cambridge, FuUerian Pro- 
fessor of Chemistry, Royal Institution, London. Received 
June 15,— Read June 20, 1901. 

Our last commimication to the Society* related to the most volatile 
of the atmospheric gases, that which we now beg leave to offer relates 
to the least volatile of those gases. The former were obtained from 
their solution in liquid air by fractional distillation at low pressure, 
and separation of the condensible part of the distillate by cooling it in 
liquid hydrogen. The latter were, in the first instance, obtained from 
the residue of liquid air, after the distillation of the first fraction, by 
allowing it to evaporate gradually at a temperature rising only very 
slowly. The diagram, fig. 1, will make the former process intelligible. 

• * Boy. Soc. Proc.,' toI. 67, p. 467. 



390 



Profs. O. D. liveing and J* Bewan On th€ 



A repreaents a vacuum-jaoketed Taasel, partly filled widi Uqiiid air, 
which a second Teasel, B^ was immetBed, Froni the bottom of J 
tube, a, pna«ed up tibrough the rubber cork which closed A^ and fp 
the top of B a second tube, h^ passed through the cork and on to \ 
rest of the apparatus* Each of these tubes had a ttopcock^ m and 
and the end of tube a wag open to the air. A wider tube a 
passed through the cork of A and led to an air-pump^ wherebj 1 



Fio. 1. 




^fe^i 



pressure above the liquid air in ^ was reduced, and the temperati 
of the liquid reduced bj the coneequeDt evaporation. To keep 
inner vessel, B^ covered with liquid, a fourth tube, r, paaaed throt 
the cork, and its lower end, furnished with a valve, p^ which could 
opened and closed by the handle ^, dipped into liquid air contained 
the vessel V, As the pressure above the liquid in A was less tl 
that of the atmosphere, on opening the valve p some of the liquid 
was forced through r into A by the pressure of the atmc^phei'e, and 
this way the level of liquid in A maintained at the required height. 

Since B was maintained at the temperature of liquid air boiling 
reduced pressure the air it contained condensed on its sides, and w\ 
the stopcock n was closed and m opened, more air passed in throi 
the open end of a, and was in turn condensed. In this way B eo 
\y% filled completely with liquid air, the whole of the most volatile g^ 
being retained in solution in the liquid. 

The tube, £, passing from the top of B^ was connected with a th] 



Separation of the Lead Volatile Gases of Aimo&pheric Air, &c. 391 

way stop-cock d, by which c could be put in communication with the 
closed vessel, D, or with the tube e, by which also D and e could be 
connected. The tube e passed down nearly to the bottom of the 
vacuum jacketed vessel E, and out again through the cork ; and on to 
a gauge /, and through a sparking tube ^ to a mercury pump F, 
The stopcock n being still closed, the whole of the apparatus between 
n and the pump, including the vessel Z>, was exhausted, and liquid 
hydrogen introduced into E, The three-way cock d was then tiu*ned so 
as to connect c with Z>, and close «, and then n opened. B was thereby 
put in communication with Z>, which was at a still lower temperature 
than B, and the gas dissolved in the liquid in B^ along with some of 
the most volatile part of that liquid, distilled over, and the latter 
condensed in a solid form in />. When a small fraction of the liquid 
in B had thus distilled, the stop-cock d was turned so as to close the 
communication between D and c, and open that between D and e. 
Gfis from D passed into the vacuous tubes, but in so doing it had to 
pass through the portion of e which was immersed in liquid hydrogen, 
so that condensible matter carried forward by the stream of gas was 
frozen out. 

For separating the least volatile part of the gases, the vessel E, with 
its contents, was dispensed with, and the tube c made to communicate 
directly with that connected with the gauge, sparking tube, and pump ; 
and generally several sparking tubes were interposed between the 
gauge and pump, so that they could be sealed off successively. The 
bulk of the liquid in B consisted of nitrogen and oxygen. These were 
allowed gradually to evaporate, the temperature of B being still kept 
low so as to check the evaporation of the gases less volatile than 
oxygen. When a great part of the nitrogen and oxygen had thus 
been removed, the stopcock n was closed, and the tubes partially ex- 
hausted by the pump, electric sparks passed through g, and the gases 
examined spectroscopically. More gas was then evaporated from By 
and the spectroscopic examination repeated from time to time. 

The general sequence of spectra, omitting those of nitrogen, hydro- 
gen, and compounds of carbon, which were never entirely removed 
by the process of distillation alone, was as follows : The spectrum of 
argon was first noticed, and then as the distillation proceeded the 
])iightest rays, green and yellow, of krypton appeared, and then the 
intensity of the argon spectrum waned, and it gave way to that of 
krypton until, as predicted by Runge, when a Leyden jar was in the 
circuit, the capillary part of the sparking tube had a magnificent blue 
colour, while the wide ends were bright pale yellow. Without a jar 
the tube was nearly white in the capillary part, and yellow about the 
poles. As the distillation proceeded, the temperatiu*e of the vessel 
containing the residue of liquid air being allowed to rise slowly, the 
brightest of the xenon rays began to appear, namely, the ^^«Cfc.^^^ 

VOL LXVIII. ^ ^ 



392 



Profs, G. D. Liveuig and J, Dewan On the> 



about X 6420, 5292, and 4922, and then the krypton rays soon died ou 
and were superseded by the xenon rays. At this stage the capillary 
part of the gparldng tube is, with a jar in circuit, a brllliaat green 
and is stOl green, though less brillianti without the jar. The xenon 
formed the final fraction distilled. 

Subsequently an improved form of apparatus was used for the frac- 
tionation. It k represented in fig. 2* A gasholder containing the 



Fio.2. 



//tUC^^^ 




gases to be separated, that is to say, the least volatile part of atmo- 
spheric air, was connected with the apparatus by the tube a, furnished 
with a stopcock c. This tube passed on to the bulb Bj which in turn 
communicated through the tube b and stopcock d with a sparking 
tube, and so on through the tube c, with a mercurial pump.* Stopcock d 
being closed and c opened, gas from the holder was allowed to pass 
into B, maintained at low temperature, and there condensed in the 
solid form. Stopcock c was then closed and d opened, and gas from B 
allowed to pass into the exhausted tubes between B and the pump. 
The tube e was partly immersed in liquid air in order to condense 
vapour of merciu'y, which would otherwise pass from the pump into 
the sparking tube. The gas passing into the sparking tube would, of 
course, have a pressure corresponding to the temperature of J5, and 
this was further ensured by making the connecting tube pass thit>ugh 
the liquid in which B was immersed. The success of the operation of 
separating all the gases which occur in air and which boil at difTerent 
* The Sprengel pump shown in figure is simplj diograxmnatic. 



Separation of the Least Volatile Oases of Atmospheric Air, &c, 393 

temperatures depends on keeping the temperature of ^ as low as 
possible, as will be seen from the following consideration : — 

The pressure p, of a gas G, above the same material in the liquid 
state, at temperature T, is given (approximately) by the formula 

log;? = ^ - ^ , 

where A and B are constants for the same material. For some other 
gas G' the formula will be 

logi?i = ^1-:^^ 

and \ogJL^A^A^ + ?lzi. 

pi T 

Now for argon, krypton, and xenon respectively the values of A are 

6-782, 6-972, and 6*963, and those of B are 339, 496*3, and 669-2 ; so 

that for these substances and many others A -Ai \b always a small 

B — B 
quantity, while — m ^s considerable and increases as T diminishes. 

Hence the ratio of p to pi increases rapidly as T diminishes, and by 
evaporating the gases always from the solid state and keeping the solid 
at as low a temperature as possible, the gas first removable at the 
lowest pressure consists in by far the greatest part of that which has 
the lowest boiling point, which in this case is nitrogen, and is suc- 
ceeded, with comparative abruptness, by the gas which has the next 
higher boiling point. By this method the nitrogen and oxygen are 
removed without the necessity of sparking or absorption. The 
change from one gas to another is easily detected by examining the 
spectrum in the sparking tube, and the reservoirs into which the gases 
are pumped can be changed when the spectrum changes, and the frac- 
tions separately stored. Or, if several sparking tubes are interposed 
in such a way as to form parallel communications between the tubes b 
and e, any one of them can be sealed off at any desired stage of the 
fractionation. 

The variation of the spectra of both xenon and krypton with varia- 
tion in the character of the electric discharge is very striking, and has 
already been the subject of remark, in the case of krypton, by Runge, 
who has compared krypton with argon in its sensitiveness to changes 
in the electric discharge. Eunge distinguishes krypton rays which are 
visible without a jar and those which are only visible with a jar dis- 
charge. The difference in the intensity of certain rays, according as 
the discharge is continuous or oscillatory, is no doubt very marked, 
but, with rare exceptions, we have found that the rays which are 
intensified by the oscillatory discharge can be a^i\ wXJti «i ^wy^*\x5Ntfssi& 



discharge when the dit of the spectroeoope is wide. Bonge uaed a 
grating, whereas we have, for the sake of more light, used a prism 
spectroscope throughout, and were therefore able to observe many 
more rays than he. 

There is one very remarkable change in the xenon spectrum pro- 
duced by the introduction of a jar into the circuit. Without the jar 
xenon gives two bright green rays at about X 4917 and X 4924, bat on 
putting a jar into the circuit they are replaced by a single still stronger 
ray at about X 4922.* In no other case have we noticed a change so 
striking as this on merely changing the character of the discharge. 
Changes of the spectrum by the introduction of a jar into the circuit are, 
however, the rule rather than the exception, and there are changes in 
the spectnmi of laypton which seem to depend on other circumstances. 
In the course of our examination of many tubes filled with krypton 
in the manner above indicated, we have found some of them to give 
with no jar the green ray X 5571, the yellow ray X 5871, and the red 
ray X 7600 very bright, while other rays are very few, uid those few 
barely visible. Putting a jar into the circuit makes very little differ- 
ence; the three rays above mentioned remain much the brightest, 
nearly, though not quite, so bright as before, and the blue rays, so 
conspicuous in other tubes, though strengthened by the use of the jar, 
are still very weak. In other tubes the extreme red ray is invisible, 
the rays at X 5571 and 5871 absolutely, as well as relatively, much 
feebler, while the strong blue rays are bright, even brighter than the 
green and yellow rays above named In one tube the blue rays could 
be seen, though not the others. This looks very much as if two 
different gases were involved, but we have not been able to assure our- 
selves of that. The case seems nearly parallel with that of hydrogen. 
There are some hydrogen tubes which show the second spectrum of 
hydrogen very bright, and others which show only the first spectrum ; 
the second spectrum is enfeebled or extinguished by introducing a jar 
into the circuit, while the first spectrum is strengthened ; and the con- 
ditions which determine the appearance of the ultra-violet series of 
hydrogen rays have not yet been satisfactorily made out. 

It is to be noted that putting the jar out of circuit does not in 
general immediately reduce the brightness of the rays which are 
strengthened by the jar discharge. Their intensity fades gradually, 
and is generally revived, more or less, by reversing the direction of 
the current, but this revival gets less marked at each reversal until the 
intensity reaches its minimum. The rays strengthened by the jar dis- 
charge also sometimes appear bright, without a jar, on first passing 
the spark when the electrodes are cold, and fade when the electrodes 
get hot, reappearing when the tube has cooled again. Moreover, if 

* This line is almost identical with a strong helium line, but the toUow line of 
helium was not seen. 



Separation of the Least Volatile Gases of Atmospheric Air, &c. 395 

the discharge be continued without a jar, the resistance in the krypton 
tubes increases rather rapidly, the tube becomes much less luminous 
and finally refuses to pass the spark. With an oscillatory discharge 
the passage of the spark and the brightness of the rays are much more 
persistent. This seems to point to some action at the electrodes, which 
is more marked in the case of krypton than in that of xenon. 

The wave-lengths of the xenon and krypton rays in the tables below 
were determined, in the visible part of the spectrum, with a spectro- 
scope having three white flint-glass prisms of 60"* each, by reference 
to the spark spectrum of iron, except in the cases of the extreme red 
ray of krypton, which was referred to the flame spectrum of potassium, 
and ite fainter neighbour, which we saw but did not measure. The in 
digo, violet, and ultra-violet rays were measured in photographs, taken 
with quartz lenses and two calcite prisms of GO"* each. The spectrum of 
the iron spark was photographed at the same time as that of the tube, 
the former being admitted through one-half of the slit, and the latter 
through the other half. 

The xenon spectriun is characterised by a group of four conspicuous 
orange rays of about equal intensities, a group of very bright green 
rays of which two are especially conspicuous, and several very bright 
blue rays. The only list of xenon rays we have seen is that published 
by Erdmann, with which our list does not present any close agreement 
except as to the strongest green lines. The number of xenon rays we 
have observed is very considerable, and some of them lie very near to 
rays of the second spectrum of hydrogen, but inasmuch as these rays 
are more conspicuous with a jar in circuit than without, which is not 
the character of the second spectrum of hydrogen, and, moreover, 
many of the brightest of the hydrogen rays are absent from the 
spectrum of the tubes, we conclude that these rays are not due to 
hydrogen. Certain rays, which we have tabulated separately, have 
been as yet observed in only one tube : they include a very strong 
ultra-violet ray of unknown origin, and either due to some substance 
other than xenon, or to some condition of the tube which has not 
been repeated in the other tubes. 

Our krypton rays agree much more closely with Runge's list, but 
outnumber his very considerably, as might be expected when prisms 
were used instead of a grating. Prisms, of course, cannot compete 
with gratings in the accuracy of wave-length determinations. We 
think that the krypton used by Runge must have contained some 
xenon, and that the rays for which he gives the wave-lengths 5419-38, 
5292*37, and 4844*58 were really due to xenon, as they are three of 
the strongest rays emitted by our xenon tubes, and are weak in, and 
in some cases absent from, the spectra of our krypton tubes. 

Our thanks are due to Mr. K. Lennox, to whose skill in manii^uLa. 
tion we are much indebted. 



396 Profs- G. D, Liveiug and J. Dewar. On the 

Tabk^ of ihe approdmde Wam-kagih^ Oj Xefwn and Kiyptm Bai^s, 

Eaya observed only with a Lejden jar in cirmit have an * prefixed, 
those obsen^ed only when no Ley den jar was in circuit have a t pre- ] 
fixed. 

The intensities indicated are approximately thoae of the raya when 
a jar is in circuit, except in the case of the two rays to which a f is 
prefixed, which are not seen when a jar is in circuit. Rays which are 
equally intense whether a jar is in circuit or not have a || prefixed to 
the mimher indicating their intensities; those which arc less intense 
with a jar than without have a < prefixed to the number expressing 
their intensities. The rest are, in general, deddedly more intense with 
a jar than without. 

Xenon Bays. 



Ware- 


Inten- 


Waye- 


Intnl. 


Ware- 


Inten- 


Ware- 


Inten- 


lengths. 


•ity. 


lepgthf. 


■itj. 


lengthe. 


•ity. 


lengths. 


sity. 


♦6596 


4 


5532 


4 


4883 


_ i 


4471 


2 ^ 


• 14 


1 


5473 


8 


76 


4 1 


62 


10 


6472 


111 


61 


3 


44 


10 


49 


6 


6358 


1 


• 51 


1 


30 


111 


40 


1 


45 


3 


39 


3 ! 


23 


3 1 


34 


2 


20 


111 


20 


10 


• 18 


3 1 


15 


8 


02 


1 


5372 


6 


07 


<1 ' 


07 


3 


6278 


3 


• 68 


1 


4793 


1 ' 


4396 


4 


71 


3 


39 


6 


87 


2 


93 


4 


6183 


111 


13 


1 


79 


2 


86 


3 


81 


111 


09 


1 


69 


2 


75 


4 


66 


111 


5292 


10 


40 


1 


69 


4 


6097 


6. 


62 


2 


34 


<1 


56 


I 


61 


6 


60 


2 


31 


1 


43 


1 


86 


5 


40 


— 


23 


1 


37 


3 


5976 


6 


27 


1 


14 


1 


31 


10 


72 





02 


1 


4698 


P 


22 


3 


46 


2 


5192 


6 


46771 


band of 


11 


3 


85 


<1 


89 


3 


to y 


close 


4297 


3 


06 


1 


85 


8 


4668 


lines 


86 


8 


5895 


11^ 


79 


3 


52 


4 


72 


8 


76 


111 


26 


3 


34 


2 


69 


3 


56 


111 


28 


1 


24 


<2 


63 


2 


25 


2 


07 


3 


16 


3 


51 


3 


17 


__ 


5060 


2 


02 


8 


45 


10 


5777 


4 


68 


5 


4592 


3 


! 39 


8 


59 


4 


52 


1 


86 


II& 


27 


1 


51 


5 


45 


6 


77 


3 


23 


5 


27 


4 


25 


<1 


56 


2 


15 


10 


20 


4 


4988 


4 


45 


3 


14 


6 


00 


6 


72 


2 


41 


3 


i 09 


S 


5668 


4 


t 24 


t4 


33 


2 


1 04 


111 


60 


1 


• 22 


8 


25 


l|5 


01 


1 


17 


— 


t 17 


t4 


22 


1 


4198 


1 


09 


1 


4890 


3 


00 


111 


93 


l|6 


5583 


1 


87 


— 


44S6 


1 


81 


10 


73 


1 


84 


4 


81 


5 


76 


1 



Separation of the Least Volatile Oases of Atmospheric Air, &c. 397 
Xenon Eays — continued 



Ware- 


Inten- 


' Wave- 


Inten- 


Wave- 


Inten- 


Wave- 


In ten. 


lengths. 


sity. 


, lengths. 


sity. 


1 lengths. 


sity. 


lengths. 


sity. 


4172 


1 


1 3981 


1 


r 

1 8815 

1 11 


1 


8655 


2 


63 


3 


' 75 


1 


8 


60 


1 


59 


3 


1 7^ 


2 


1 07 


1 


45 


6 


46 


8 


' 67 


111 


01 


1 


41 


2 I 


42 


1 


55 


4 


3792 


1 


32 


2 


32 


2 


51 


<6 


87 


1 


24 


10 


21 


1 


44 


3 


83 


1 


16 


1 


12 


2 


39 


1 


81 


6 


13 


4 


09 


6 


2H 


1 


76 


8 


10 


2 


06 


8 


23 


6 


73 


1 


07 


4 


00 


2 


15 


1 


70 


1 


02 


I 


4099 


3 


08 


4 


66 


1 


3597 


8 


93 


1 


06 


1 


63 


2 


84 


8 


79 


<1 


03 


1 


62 


1 


80 


8 


74 


1 


3894 


3 


57 


1 


65 


4 


60 


1 


85 


3 


46 


8 


56 


3 


58 


6 


80 


3 


87 


1 


53 


5 


50 


6 


77 


8 


31 


2 


43 


6 


44 


1 


70 


2 


21 


2 


23 


4 


43 


1 


62 


2 


17 


3 


10 


2 


37 


6 


! 58 


2 


1 12 


2 


04 


I 


29 


1 


; 55 


1 


1 08 


1 


01 


4 


25 


3 


1 50 


2 


8689 


1 


8468 


2 


1 21 


1 


1 *9 




77 


8 


61 


1 


1 02 


3 


1 42 




73 


2 


54 


1 


3994 


2 


29 




64 


1 






91 


3 


1 26 




62 


2 






' 86 


I 


24 




58 


1 







Wave-lengths of rays of unknown origin observed ih the spectrum 
of one tube containing xenon but not present in the spectrum of other 

tubes : — 



Wave- 


Inten- 


Wave- 


Inten- 


lengths. 


sity. 


lengths. 


sity. 


4589 


_ 


3890 


1 


4071 


1 


72 


1 


67 


1 


3797 


5 


63 


1 


41 


4 


11 


1 ' 


8684 


10 


3998 


1 


3578 


2 



398 Separation, of the Lead Volatile Oases of Atmospheric Air^ Jte. 



Krypton Says. 



Ware- 


Inten- 


Waye- 


Inten- 


Ware- 


Inten- 


Wave- 


Inten- 


lengths. 


tity. 


lengths. 


sity. 


lengths. 


sity. 


lengths. 


sity. 


7600 


8 


5186 




4887 


3 


8869 




J7587 


2 


72 




76 


s 


58 




6771 


1 


66 




63 


2 


47 




6578 


1 


48 


. 


56 


12 


i 44 




42 


8 


26 




28 


2 


42 




11 


2 


5087 




1 20 


l|8 


89 




6487 


8 


78 




19 


l|3 


87 


2 


58 


<1 


78 




18 


3 


17 


2 


51 


8 


67 




01 


7 


06 


2 


20 


<4 


84 




4293 


10 


05 


8 


6305 


8 


23 




88 


l|3 


3784 


10 


6170 


2 


14 


I|2 


74 


l|4 


79 


8 


6095 


1 


4980 




69 


8 


72 


4 


82 


1 


60 




60 


1 


69 


2 


56 


2 


46 




56 


1 


55 


6 


21 


1 


03 


2 


51 


5 


46 


6 


11 


2 


4847 


2 


37 


4 


42 


6 


5992 


3 


45 


2 


4185 


3 


86 


3 


5873 


1 


• 33 


5 


72 


1 


34 


4 


71 


<10 


26 


3 


45 


8 


22 


5 


6771 


2 


1 12 


3 


40 


2 


19 


10 


53 


2 


4766 


10 


4119 


3 


15 


1 


5690 


5 


63 


3 


09 


6 


3691 


1 


82 


5 


39 


10 


4099 


8 


87 


5 


50 


1 


4694 


3 


89 


8 


81 


7 


32 


2 


80 


5 


65 


7 


70 


7 


6571 


<10 


59 


8 


68 


6 


67 


1 


63 


3 


. 50 


1 


45 


4 


G4 


3 


58 


1* 


35 


6 


; 38 


2 


61 


3 


44 


1 


20 


8 


OS 


2 


54 


10 ; 


23 


2 


15 


6 


05 


1 


49 


« i 


06 


2 


10 


3 


3997 


3 


38 


4 


00 


2 


4598 


1 


94 


6 


32 


10 


5483 


1 


93 


2 


88 


2 


24 


1 


46 


2 


83 


4 


65 


1 


08 


6 


29 




1 77 


8 


55 


2 


00 


6 


24 




25 


8 


89 


1 


3590 


3 


03 




05 


l|2 


; 28 


3 


74 


1 


5319 




4490 


2 


21 


8 


54 


2 


05 




75 


6 


18 


2 


45 


6 


5278 




64 


||3 pairs 


13 


6 


03 


2 


29 




54 


111 


07 


6 


3489 


2 


18 




87 


6 


01 


1 


70 


1 


15 




82 


6 


' 3896 


3 


60 


3 


• 09 


5 


23 


2 


76 


7 






08 


1 


00 


1 


62 


1 







X This is taken from Range's number for the wave-length, omitting the fraction. 



Further Observations on Nova Persei, 



399 



" Further Observations on Nova Persei. No. 3." By Sir Norman 
LocKYER, K.C.B., F.E.S. Keceived May 17,— Eead June 20 
1901. 

In the last paper* I gave an account of the observations of the 
Nova made at Kensington between March 5 and March 25 inclusive. 
The observations are now brought up to midnight of May 7. Between 
March 25 and the latter date, estimates of the magnitude of the 
Nova have been made on thirty-three evenings, visual observations of 
the spectrum on twenty-five evenings, and photographs of the spectrum 
on six evenings. 

The 10-inch refractor with a McClean spectroscope has generally 
been used for eye observations. The 6-inch prismatic camera has not 
been available for photographing the spectrum owing to the faintness 
of the Nova, but photographs have been secured by Dr. Lockyer with 
the 30-inch reflector on the nights of March 27, April 1 and 12, and 
by Mr. Fowler on March 26 and April 4. With the 9-inch prismatic 
reflector the spectrum was photographed by Mr. Hodgson on March 30, 
April 1 and 4. 



Change of Brightness. 

Since March 25 the magnitude of the Nova has been undergoing 
further periodic variations, and although observations have not been 
made on every night since that date, owing to unfavourable weather, 
yet suflicient data have been gathered to enable a general idea of the 
light changes to be obtained, and the few gaps can be filled up later 
by other observers who experienced clearer skies on these occasions. 

The following table is a continuation of the observations for magnitude. 
Columns (1), (2), and (3) denote the observations made by Dr. Lockyer, 
Mr. Fowler, and Mr. Butler respectively, and Column (4) includes 
other estimates made by Mr. Baxandall and Mr. Shaw. The numbers 
in brackets represent the Greenwich mean time at which the observa- 
tions (against which they are printed) were made, and refer to the 
evening hours (p.m.), except where otherwise stated. 

Magnitudes of Nova Persei. 







(1) 






(2) 


(3) 


(4) 


March 26.... 


4-2 


(10. 30) 




4-2 


(10 30) 






„ 27.... 


3-9 






4-2 




— 


4-2 F.E.B. 


„ 28.... 


— 






5-3 




5 3 


<5-0 H.S. 


„ 30.... 


— 











4*2 


4 -2 H.S. 


„ 31.... 


4 8 






4-3 




— 


— 


April 1.... 


4-4 






— 




4-4 


— 


4.... 


4-3 


(7.0) 




4-4 




4-5 


— 






• 


Page 


230, 8upv^. 







400 



Sir Norman Lockyeiv 

Magnitudes of Nova Persei — continufd. 



Apni 


B 




6 




7 


>» 


8 


11 


9 


n 


10 


t» 


11 



,. 12 

„ 18, 
.. 14. 



15 . 

16. 
17. 
18. 
19. 
20. 
21, 
22. 
24. 
25. 
26. 
27. 
80. 

3 . 

4. 

5. 



I f8.46) 
(9.40) 



May 



(1) 
4-8 (10.0) 
6 '5 (8. a}) 
6-0 (7.80) 
4-2 (11.0) 
4 7 (11.80) 
6-7 (8.46) 
6-8 
f6-2 

U-e . 

4-6 (11.80) 

5*4 (9.80) 

re-oor 

4fiiinter (aO) 
[5 -8 or 9 (10. aO) 
6-5 (11. 0) 

6-2 (aso) 

4*2 (9.0) 

6-2 (ao) 

5-9or6'0(a80) 
6-1 (».0) 
6-7 (9.0) 
<6'6 (8.80) 

5 -7 or 8 (8. 15) 
5-6 (9.0) 

4-4 (9.15) 
<5-6 (9.15) 
5-7 (9.0) 

6 (2.151.M.) 



(2) 
4-5 

6*6 

4*5 



(3) 



60 
6-6 
6-6 or7 

6*8 



W 




4-8 



6-0 



FJU3. 
F.E3. 



4*2 



48(8.0) — 
6 "6 — 

6-0 — 



6-1 (a 80) — 

4-2 4*8 H.8. 



<6*6(8.86) 



5-7 

5-5 (9.0) 

5-8(9.40) 
6-8 



6-6(8.80) 
6'Oorl (9.0) 



6-6 (9.0) 
5 -5 (9. 0) 
4 -5 (8. 0) 



5-8 
5-6 



4-4H.S. 



It is interesting to' note that the length of the period of variability, 
reckoning from maximum to maximum, began after March 27 to 
increase from three days to four days. 

The two following maxima, after that of April 8, occurred on the 
13th and 18th, so that the period became still more lengthened, namely, 
to about five days. Further observations up to May 5 seem to 
indicate that the five-day period is shortening. 

Another interesting observed fact was that the light of the Nova 
at the minimum on the 25th was more intense than at the preceding 
minimum on the 21st, the estimated difference of magnitude at these 
times being about 4-tenths of a magnitude. Unfortunately the 
increasing twilight and the unfavourable position of the Nova make 
it very difficult now to determine the magnitudes correctly. 

The two plates accompanjdng this paper illustrate graphically the 
various fluctuations of the light of the Nova from February 22, when 
it had not quite attained its maximum brilliancy, to May 5. 

The curve is drawn to satisfy as far as possible all the observations 
made at Kensington. The dotted portions represent the possible light- 
curve for those times when no estimates for magnitude could be 
secured. 

In the plates the absciss® represent the time element and the 
''Minates that of magnitude. 



Further Observations on Nova Persei. 



401 




402 



Sir Norman Lockyer. 



<0 












SJ 




» 












J^ 






•0 








^___, 


^-— 


^fl*^ 






v 






r 












1- 








*'-- 


-*-_^ 








s 












"^ 






« 










P.r-'' 


-^ 






t 






c 


■^^ 










19 








'^-^ 


^^^ 


















^ 






i 












t 






— 


^ 


.^*- 


■^ 






S3 






c: 


--— , 


•*^ 








5 














L 


g 












^ 


^ 


■ 












>^ 






1 






-C 


,,--*^ 


-^ 






oc. 


n 


,^ 








^^ 


t! 










% 








% 












N 




g 


% 












^ 




z > 


^ 








^^^^ 


— " 








^ 






C 


-" 










^ 








1^ 


*v_ 






^ 












? 






% 










^ 


^ 






^ 






^ 


i^^H 










« 






^ 


.•^^ 










h 












.7 






c 








^ 


.^ 








^ 






c: 










^ 






TW 


*-— * 


*-•■ 








^ 


















^^ 








^-- 


'"^ 












/ 













In the first part of the period covered by the later observations, the 
colour of the Nova has been generally described as yellowish-red, red 
with a yellow tinge, and yellow with a reddish tinge. Since April 25 
the colour has been perhaps more red than formerly, and sometimes 
noted as very red. 

It is interesting to remark that the colour varies periodically with 
the change in magnitude. At maximum it is of a distinct yellowish- 
red hue, but at or near minimum the yellowish tinge disappears and 
the Nova appears very red. 



Further Observaiions on Nova Perset 403 

The Visual Spectmm. 

In the continued observations the C and F lines of hydrogen have 
always been recorded as " conspicuous," other prominent lines being 
near X447, X465, and X501 (the last named being sometimes as 
bright as F or even brighter), and a line in the yellow which recent 
measures show to be D3. 

The strong lines in the green at XX 4924, 5019» 5169, and 5317, 
which occurred in the earlier photographs, and which were ascribed to 
iron, are either absent from the later photographs or appear only aa 
very weak lines. 

It has been noted that the lines 447, 501, and D3 appear to vary 
with the magnitude of the star, becoming relatively more prominent 
towards a minimum. 

The continuous spectrum has been described throughout as " weak '* 
or " very weak." 

On the evening of April 25, Messrs. Fowler and Butler made 
comparisons of the Nova spectrum with the spectra of hydrogen, 
helium, and that furnished by an air spark between poles of iron and 
zinc. For this purpose a Hilger two-prism star spectroscope was 
used with the 10-inch refractor. The hydrogen line F and the helium 
line D3 were found to be sensibly coincident with Nova lines. '!5,The 
middle of the strong green line, previously mentioned as X501, 
practically coincided with the nitrogen line 5005*7, and therefore 
there is little doubt that it is identical with the chief nebular line 
X 5007-6. This line was also compared with the asterium line at 
X 5015*7, but was found to be decidedly non-coincident with it, 
though of sufficient breadth to nearly reach it. 

Photographic Spectnim. 

In so far as the number and positions of the lines are concerned, 
the few photographs available for discussion were obtained in the 
early part of the period dealt with in the present paper (March 26 to 
May 7), and show a spectrum very similar to that of March 25, which 
was described in detail in the last paper. The chief lines shown in 
the photographs are Hj3, Hy, H8, He, and H^, together with 4471 
and 4650. 

Charactei'istics of H/?. 

In continuation of the series of light curves of H^ reproduced in 
the last paper, I give those plotted by Mr. Baxandall from the later 
photographs. 

It will be seen that the line Hj3 still shows two maxima of intensity. 
As recorded in the previous paper, the less refrangible co\3a^\vetv\i ^%^ 



404 



Tidal Edijm of the San, May 2%, 1900. 



fW^M 






LIQHT CURVE op H^ 
f^O'meh nfUo6on. 

indications of becoming brighter than the more refrangible member. 
These further photographs indicate that by April 4 the less refrangible 
had become twice as intense. 



"Total Eclipse of the Sun, May 28, 1900.— Account of the 
Observations made by the Solar Physics Observatory Eclipse 
Expedition and the Ofl&cers and Men of H.M.S. * Theseus ' at 
Santa Pola, Spain." By Sir Norman Lockyer, K.C.B., F.R.S., 
Received May 21,— Eead June 20, 1901. 

(Abstract.) 

The Report gives details as to the erection of coronagraphs, 
prismatic cameras, and other instruments, and of the results obtained 
by their use during the eclipse, which was observed imder very favour- 
able circiunstances. Some of the more obvious results have already 
been stated in a Preliminary Report,* and the following remarks may 
now be added. 

A comparison of the photographs taken with the coronagraph of 
16 feet focus with those taken about two hours earlier in America 
indicates that while some of the prominences changed greatly in 
appearance in the interval, no changes were detected in the details of 
the corona. 

The spectrum of the chromosphere, as photographed with the 
prismatic cameras, so greatly resembles that of 1898 that it has not 
been considered necessary to make a complete reduction of wave- 

• * Eoy. Soc. Proc./ toI. 67, p. 341. 



On the ProthcUli of Opliioglossum pendulum (i.)> ^<^' 405 

lengths. The prominences visible during totality had comparatively 
simple spectra, the greatest number of lines recorded being 36. 

The heights above the photosphere to which many of the vapours 
can be traced in the photographs are tabulated and compared with 
the results obtained in 1898; the two sets of figures are sufficiently 
accordant, except in the case of the shorter arcs, the value 475 miles 
derived for the lowest measurable vapours in 1898 being represented 
in 1900 by two strata, one reaching to 7t)0 miles and the other to 270 
miles above the photosphere. 

The bright-line spectrum of the corona was decidedly less bright 
than in 1898, and a much smaller number of rings is seen in the 
photographs. The three brightest rings are at wave-lengths 5303*7, 
4231*3, and 3987 0, and it may be noted that these were also the 
brightest in the eclipses of 1893, 1896, and 1898. The conclusion 
that the different rings do not originate in the same gas, arrived at 
from a discussion of the photographs of 1898, has been confirmed. 

A drawing is given to illustrate the fact that while the details of the 
green coronal ring are seen in the inner corona, they have no apparent 
relation to the positions of the great streamers or prominences. For 
an investigation of this nature the photographs taken with the pris- 
matic camera of 20 feet focal length are specially valuable. 



" Preliminary Statement on the Prothalli of Ophioglossum pen-' 
dvlum (Jm\ Helminthostachys zeylanica (Hook), and Psiloium, 
sp." By William H. Lang, M.B., D.Sc., Lecturer in Botany, 
Queen Margaret College, University of Glasgow. Communi- 
cated by Professor F. 0. Bower, Sc.D., F.R.S. Eeceived 
May 20,— Ptead May 23, 1901. 

During a recent visit to Ceylon and the Malay Peninsula* the 
author found prothalli of Ophioglossum pendulum and Helminthostachys 
zeylanicUy as well as a single specimen, which there is reason to regard 
as the prothallus of Psilotum, As the examination of the material will 
occupy a considerable time, it has seemed advisable to give a brief 
description of the mode of occurrence and external morphology of the 
prothallus in these three plants, without entering into details of struc- 
ture or discussing the phylogenetic bearing of the facts. 

The chief gaps in our present knowledge of the gametophytes of the 
more isolated living Fteridophyta concern the Ophioglossacece and Lyco- 
podiacem^ to which groups the prothalli described below belong. The 

* The expenses of the yisit to the Malay Peninsula were defrayed by a g^rant 
from the Boyal Society. 



406 



Mn ^Y. H. Lang. On the ProthalH of 



prothalhifl of Ophmjhssnm jf^duncuhMttm^ wjis described by Mettenius in j 
1856, It wiis subterranean, can sis ting of a small tuber, from which an 
erect cylindrical l>ody proceeded. On the Utter, which in some 
ijistances was oTiserved to reach the surface and turn g^reen, the sexual 
organs were l>orne. The fii^st divisions in the germinating spore of 
0. p^mlulnmf are described and figured by Campbell, The prothalli 
of two speciea of Botnjrhium are known, both of which arc subterranean . 
That of li. m-ijinutmim \ is thick and flattened , and in it« structure and 
in the localisation of the sexual organs on the upper surface dearly 
dorsiyentral. The prothalli of J3. LanariaJ^ however, have sexual 
organs on all sides. In the Lyoopodiaum the prothallus is well known 
in die heterospbrous forms and in Lycopodium. The sexual generation 
is entirely unknown in the PsUctacecB and in PhyUoglasmm. If the 
author is correct in attributing the prothallus to be described below to 
PsUotarOj the only two isolated genera of existing Vascular Cryptogams 
in which the gametophyte is entirely unknown are Tmes^^kris and 
Phyllaglosgum. 






Fig. 1. 



Fig. 2. 



Fig. 8. 



Fig. 1. OphiogJossum pendulum^ old prothallus from above. ( x 7.) 
Fig. 2. Helminihostachys zeylanicat prothallus, bearing antheridia, from the 
side. ( X 7.) 

Fig. 3. Pnlotum, sp., prothallus from the side and slightly from above. ( x 7.) 

Ophioghssum pendulum. 

The sporophyte of this plant was, for the most part, found growing 
on the humus collected by such epiphytic ferns as Polypodium guerd- 
folium d^nd A^lenium nidus, A large mass of the former, with the 
Ophioglossum growing upon it, was collected in the Barrawa Forest 

• * Filices Horti Bot. Lipsiensis/ Leipzig, 1856, p. 119. 

t * Mosses and Ferns,' London, 1895, p. 224. 

J Jeffrey, * Trans. Canadian Institute,* 1896-7, p. 266. 

§ Hofmeister, * Higher Cryptogamia,' London, 1862, p. 807. 



Ophioglossum pendulum (L,), &c. 407 

Reserve,* near to Hanwella, in Ceylon. On the humus contained in 
this being carefully examined prothalli of various ages were found. 
They were distributed throughout the humus, the majority being found 
near the bottom of this, often embedded among the ramenta which 
clothe the rhizome. 

The very young prothalli are button-shaped, the slightly conical 
lower part expanding above. The basal region is brownish, the surface 
of the upper portion a uniform dull white. The latter tint is due to 
the close covering of paraphyses, which, at this age, extends unin- 
terruptedly from just above the base over the whole surface of the 
prothallus. The youngest prothalli are thus clearly radially sym- 
metrical. In slightly older prothalli, seen from above, the circular 
outline is lost, owing to the more active growth of two 6r three points 
on the margin. This continues, and there thus arise a corresponding 
number of cylindrical branches, the prothallus becoming irregularly 
star-shaped. At first the branches spread out in a horizontal plane, 
though with a slight upward tendency. But when the branches them- 
selves subdivide all suggestion of this secondary dorsiventrality is lost, 
and the larger prothalli consist of branches radiating in all directions 
into the humus (fig. 1). 

From a short distance behind the smooth, bluntly conical apex the 
surface of the branch is covered with short, wide, unicellular paraphyses 
analogous to those known in prothalli of LycopocHum Phlegmaria, These 
are only absent above the sexual organs. 

The prothalli are monoecious, antheridia and archegonia being found 
close together on the same branch. The surface projects very slightly 
above the large sunken antheridium; the neck of the archegonium, 
which, as seen from above, is composed of four rows of cells, hardly 
projects from the prothallus. The sexual organs thus resemble those 
of 0. pedunailosumy as described by Mettenius. 

Rhizoids have not been seen on any of the numerous prothalli ex- 
amined. An endophytic fungus occupies a middle zone of tissue in all 
the branches, the superficial layers and a central core of cells being 
free from it. 

Helminthostachjs zeylanica. 

The prothalli of this plant were also found in the Barrawa Forest 
Reserve, a low-lying jungle subject to frequent floods. Young plants 
still attached to the prothallus were fairly abundant in certain spots, 
and, by searching in the rotting leaf mould around, prothalli of various 
ages were obtained. The prothalli were found at a depth of about 
2 inches. 

* I am indebted to my friend Mr. F. Lewis, who guided me to this locftlitj, for 
the assistance be afforded me in my search for the prothaUus of OphioglottM.fn, vkA. 
ffelminthosiachys, 

VOL. LXVIIL "^ ^ 



408 Mr. W. H. Lang. On the ProtkaiH of 

The youngest prothfilius ol>taiiied wiia a abort cylindrical body a littli 
over onfr-sixteenth of an inch in length. The lower end was tiarker in 
tint and hore a number of short rhizoids, while above this, where the 
antheridia were situated, the surface was of a lighter colour- The 
apex itself was bluntly conical and almost white. In slightly Lirger 
prothalli the contrast between these two regions was more strongly 
marked. The lower, vegetative region incre^ises in siise itnd becomes 
lobed, while the antheridia are confined to the cylindrical upper 
portion, which continues to increase in length* This latter region 
appears to l>e longer and the lobed basal part relatively less developed 
in prothalli which I>ear the antheridia (fig. 2). Seven of the young 
prothalli found were male ; the other two l>ore archegonia oidy. 
These female prothalli were stouter and more lobed than the male 
ones, and the diameter of the short apical region, on the surface of 
which the an^he^onia were situated, ^va*^ MbnnHt the p;tme m^ thnf of 
the vegetative region. There thus appears to be a partial sexual 
differentiation in the prothalli of Hdminthostachys^ but both antheridia 
and archegonia may occur on the same prothallus, as some of the latter 
attached to young plants have shown. The antheridia are large and 
often closely crowded together. They hardly project from the 
surface, the wall being only slightly convex. The archegonial neck, 
which is formed of four rows of cells, projects distinctly from the 
prothallus. 

The distinction made above between a vegetative and a reproductive 
region in this prothallus is supported by the distribution of the 
endophytic fungus. This is entirely absent from the reproductive 
region, but in the basal part occupies a wide zone between the two 
or three superficial layers of cells and the central tissue, which are free 
from the fungus. 

The young plants attain a considerable size while still attached to 
the prothallus. Plants with three leaves and as many roots have 
been seen, the prothallus of which showed no sign of decay. The 
first leaf is ternate and has a leaf-stalk of variable length. The 
lamina is green and reaches the light. A single root corresponds to 
each of the early leaves. 

Examination of the prothalli connected with young plants indicates 
the position they occupied in the soil. Most commonly the long axis 
of the prothallus was vertical; sometimes, however, it was oblique, 
fuid occasionally horizontal. 

Psilotum^ sp. 

The prothallus of this plant was looked for without success in 
Ceylon, both in the mountain region and on the roots at the base of 
Cocos palms near the coast. In the localities visited on the west coast 
-^ the Malay Peninsula Psilotum was not abundant. On Maxwell's 



Ophioglossum i)endiUura (i.), &c. 409 

Hill, in Perak, I found it scantily on stems of tree-ferns, the rhizome 
growing among the roots of the fern, which cover the stem. No 
young plants were found ; but a single prothallus, embedded among the 
roots of the fern in close proximity to a plant of Pdlotnm^ was 
obt^iined. This prothallus, as will be evident from ^g, 3 and the 
description below, could only belong to Psilotum, or be that of some 
species of LijcopocUumy the gametophyte of which has not been de- 
scribed. From the position in which it was found, the former suppo- 
sition is the more probable one, but such evidence of association is of 
course not conclusive, and the apecimen mn only he desci'ibed as the 
prothallus of Psilotum vjith the reservation exp-essed above. 

The prothallus when fresh measured about one-quarter of an inch in . 
length by about three-sixteenths of an inch at the widest part, which, 
as fig. 3 shows, is above. The lower portion is cylindrical and rounded 
below. To one side near the lower end is a well-marked conical pro- 
jection directed obliquely downwards, which clearly corresponds to 
the primary tubercle of the prothallus of Lycopodmm cemmim. The 
surface of the lower three-fourths of the prothallus was browTi and 
bore rhizoids. The latter were absent from the upper part, which 
widens out suddenly, the increase in ^iddth being due to the projection 
of the thick, coarsely lobed margin of the summit of the prothallus. 
The central region of the summit is smooth and somewhat depressed. 
The upper portion of the prothallus had a faint green tint when fresh, 
but no chlorophyll grains could be detected. 

In the tissue of the overhanging margin the numerous sunken 
antheridia occur, closely crowded together. Archegonia have not been 
observed on external examination. 

In its form this prothallus e\'idently presents resemblances to pro- 
thalli of Lycopodium. In the lower part it resembles the prothalli of 
the Lycopodium cei-nuum type, while the appearance of the upper 
portion suggests a comparison with prothalli of L, ckimtum or L. anni - 
tinum. There seems no reason to doubt that the meristem will be 
found at the junction of the upper and lower regions. 

Probably this prothallus was completely embedded among the roots 
of the fern. As some of the roots had been removed before the 
prothallus was noticed, this point was not definitely settled ; but the 
general appearance of the upper portion, and the absence of assimi- 
lating lobes, makes it probable that the upper surface was not exposed 
CO the light. 

That the facts stated above bear on the relationship of the plants to 
which these prothalli belong will be obvious from the brief description 
given. The discussion of this will, however, be best deferred until the 
full account, which is in coiu^e of preparation, is completed. 



VOL. LXVIIJ. "1 ^ 



410 Mrs. H. AyrtoiL 

''The Mechanism of the Electric Arc" By (Mis.) Hkbtha 
Aybton. Communicated by Professor Peert, F.RS. 
Eeceived June 5, — Read June 20, 1901. 

(Abstract.) 

The object of the paper is to show that, by appljdng the ordinary 
laws of resistance, of heating and cooling, and of burning to the are, 
considered as a gap in a circuit furnishing its own conductor by the 
volatilisation of its own material, all its principal phenomena can be 
accounted for, without the aid of a large back E.M.F., or of a " negatiTe 
^resistance," or of any other unusual attribute. 

The Apparent Uirge Back E.M.F. 

It is shown how volatilisation may begin, even without the self- 
induction to which the starting of an arc, when a circuit is broken, is 
usually attributed ; and it is pointed out that, when the carbons are 
once separated, all the material in the gap cannot retain its high 
temperature. The air must cool some of it into carbon mist or for^y jiist 
as the steam issuing from a kettle is cooled into water mist at a short 
distance from its mouth. The dissimilar action of the poles common 
to so many electric phenomena displays itself in the arc at this point. 
Instead of both poles volatilising the positive pole alone does. It is 
considered, therefore, that the arc consists of (1) a thin layer of 
carbon vapour issuing from the end of the positive carbon, (2) a bulb 
of carbon mist joining this to the negative carbon, and (3) a sheath of 
burning gases, formed by the burning of the mist, and the hot ends of 
the carbons, and surroimding both. The vapour appears to be indicated 
in images of the arc by a sort of gap between the arc and the positive 
carl)on, the mist by a purple bulb, and the gases by a green flame. 

The flame is found to l>e practically insulating, so that nearly the 
whole of the current flows through the vapour and mist alone. It is 
suggested that the vapour has a high specific resistance compared with 
that of the mist, and that it is to the great resistance of this vapour- 
film that the high temperatiue of the crater is duo, and not to any 
large back E.M.F. of which it is the seat. 

Volatilisation can only take place at the surface of contact between 
the vapour film and the positive carbon. When that surface is smaller 
than the cross-section of the end of the carbon, it must dig down into 
the solid carbon and make a pit. The sides of the pit, however, must 
be hot enough to burn away where the air reaches them, hence there 
is a race between the volatilisation of the centre of the carbon and the 
burning of its sides that determines the shape of the carl)on. When 
the arc is short, the air cannot get so easily to the sides of the 



The Mechanism o/tlie Ukdiic Arc. 411 

pit, hence it remains concave. When the arc is long, the burning of 
the sides gains over the volatilisation of the centre, and the surface of 
volatilisation becomes flat, or even slightly convex. 

The peculiar shaping of the negative carbon is shown to be due to 
its tip being protected from the air by the mist, and its sides being 
burnt away imder the double action of radiation from the vapour 
film and conduction from the mist, to a greater or less distance, 
according to the length of the arc and the cross-section of the vapour 
film. 

It is shown that if the crater be defined as being that part of the 
positive carbon that is far brighter than the rest, then the crater must 
be larger, with the same ciurent, the longer the arc, although the area 
of the volatilising surface is cansimU for a constant current. 

By considering how the cross-section of the vapour film must vary 
with the current and the length of the arc, it is found that its 
I'csistance /, must be given by the formula 

- h h + ml 

where /f, /*, and m are constants, I is the length of the arc, and A the 
current. This is the same form as was found by measiunng the P.D. 
between the positive carbon and the arc by means of an exploring 
carbon, and dividing the results by the corresponding currents. Hence 
the existence of a thin film of high-resisting vapour in contact with the 
•crater would not only cause a large fall of potential Ijetween the 
positive carbon and the arc, exactly as if the crater were the seat of a 
large back E.M.F., but it would cause that P.D. to vary "with the 
current and the length of the arc exactly as it has been found to vary 
by actuiil measurement. 

The JjypareiU " Xegative Iksisiance.** 

As nearly all the ciurent flows through the vapour and mist, the 
surrounding flame Ijeing practically an insulator, the resistance of a 
.solid carbon arc, apart from that of the vapour, must depend entirely 
on the cross-section of the mist. To see how this varies with the 
current, images of an arc of 2 mm. were cbawn, with the purple 
part — the mist — very carefully defined, for currents of 4, 6, 8, 10, 12, 
and 14 amperes. The mean cross-section of the mist was found to 
increase more rapidly than the current, consequently its resistance 
diminishes more rapidly than the current increases. As the formula 
for the resistance of the vapour film shows that it too diminishes faster 
than the current increases, it follows that the whole resistance of the 
arc does the same, and that consequently the P.D. must diminish as the 
•current increases. Hence if SV and 6A l>e correspoudi\\^\\vc^^TDkffi«c>5v*"9k ^ 

^ Vi ^ 



412 Mrs. H. Ayrton. 

P.D. and current SV/SA must be negative, although the resistance of the 
arc is positive. 

It is found, from the above measurements of the cross-sections of 
the mist, that the connection betn^-een m, the resistance of the mist, 
and the current, is of the form, 

a P 
If m varies directly with the length of the arc, then 



-(x^S)'- 



Adding this equation to (I), we get 

for the whole resistance of the arc, which is exactly the form that 
was found by dividing direct measurements of the P.D. Ijetween the 
carl>ons by the corresponding ciurents. Hence there is no reason why 
this ratio should not represent the fnif resistance of the arc. 

Under tcJmf circumstawrs SV/SA mejimrfs tin* True UesUianre of th^ Arr, 

When the current is changed it takes some time for the vapour 
film to alter its area to its fullest extent, and still more time for the 
Carlson ends to change their shapes. All the time these changes are 
going on the resistance of the arc, and, consequently, the P.I). 
l>etweeu the carbons, must be altering also. Both these, therefore, 
depend not only on the current and the length of the arc, but also, till 
everything has l)ecome steady again, /.<'., till the arc is " normal *' 
again, on how lately a change has been made in either. At the first 
instant after a change of current, before the volatilising area has had 
time to alter at all, 5V and 5A must have the same sign, just as they 
would if the arc were a wire, but as the volatilising surface alters, the 
sign of 6V changes. If, therefore, a small alternating current is applied 
to the direct current of an arc, it will depend on the frequency of that 
ciurent whether SVjBA is positive or negative. WTien the frequency 
is so high that the volatilising surface never changes at all, 8V/8A 
vriW measure the true resistance of the arc, luiless it has a back E.M.F. 
which varies with the alternating current. 

The measiu*ements of the true resistance of the arc made in this 
way by various experimenters have given very various residts, because 
proliably the frequency of the alternating currents employed has l>een 
too low not to alter the resistance of the arc. A curve is drawn 
showing how the value of BYlSA with the same direct current and 



The Mechanism of the Electric Arc, 41 3 

length of arc v«anes with the frequency of the alternating current, and 
it is pointed out that even if the arc has as large a back E.M.F. as is 
usually supposed, the frue resistance cannot be measured M'ith an 
alternating current of lower frequency than 7000 complete alternations 
per second. 

The exact conditions under which the true resistance of the arc can 
be measured in this way are examined, and the precautions that it is 
necessary to take to ensure the fulfilment of these conditions are 
enumerated. 



TJir (lminf(':i iiiti'wlured into the Uf'niMnwe of the Ave hij the i's/' (f CorM 

i^arbons, 

A core in either or both carbons has a great effect on both the P.l). 
between the carbons and the cJunige of P.D. that accompanies a given 
rlunff/e current. It lowers the first, and makes the second more 
positive, i.e., gives it a smaller negative or larger positive value, as 
the case may be. It is pointed out that this might be due to the 
influence of cores either on the cross-section of the arc, or on its 
specific resistance, or on both. 

To see the effect on the cross-section, enlarged images were drawn 
of 2 mm. arcs with currents increasing by 2 amperes from 2 to 14 
amperes, 1>etween four pairs of carbons, + solid - solid, 4- solid 
- cored, -H cored - solid, + cored - cored. Two sets of images 
were drawn with each pair of carbons — the one immediately after a 
change of current, to get the " non-normal " change, and the other 
iifter the arc had liecome normal again. The mean cross-section of 
the mist was calculated in each case, and its cross-section where it 
touched the crater was taken to be a rough measure of the cross- 
section of the vapour film. 

It was found that the mean cross-section of the mist with a given 
current was largest when both carbons were solid, less when the 
negative carbon alone was cored, less still when the positive alone was 
cored, and least when both were cored. Coring either the positive 
cavl)on alone, or both carbons, had the same effect on the cross-section 
of the vapoiu* film as on that of the mist, but coring the negative 
alone only diminished this cross-section immediately after a change of 
ciu-rent, but not when the arc had become normal again. Hence it 
was deduced that if the cores altered the cross-secti/ms of the arc only 
they woidd increase its resistance, and, consequently, the P.D. between 
the carbons. As they loiver this, however, they must do it by lowering 
the .specific resistance of the arc more than they increase its cross- 
section. The vapour and mist of the core must therefore have lower 
specific resistances than the vapour and mist of the solid carbon. 

When it is the positive carbon that is cored, all iVvfe x^'^wcc .eocv\\jKv«^ 



414 The Mcchanvm of the Sledrie Arc 

come fiom the fored carbon. When the^negative, they come from the 
vncomf carbon, and it is only because the metallic salts in the core 
have a lower temperature of volatilisation than carbon that the mist is 
able to volatilise these and so lower its own specific resistance. 

The effect of a core in either carbon, or in both, must depend on 
the current, because the larger the current the more solid carbon will 
the volatilising siuiace cover, and the less therefore will the specific 
resistances of the mist and vapour be lowered. The way in which the 
core acts in each case is traced, and the alterations in the specific 
resistances and cross-sections due to the core are shown to bring about 
changes in the P.D. exactly similar to those found by actual measure- 
ments of the P.D. between the carbons. It is shown, for instance, how 
these changes entirely account for the fact established by Professor 
Ayrton* that, with a constant length of arc, while the P.D. diminishes 
continuously as the ciurent increases, when both carbons are solid, it 
sometimes remains constant over a wide range of current, or even 
increases again, after having diminished, when the positive carbon is 
cored. 

The alterations in the value of SVjSA introduced by the cores are 
next discussed, and it is shown that the changes in the resistance of 
the arcs that mfisf follow the observecl changes in its cross-section, 
coupled with the alterations that must ensue from the lowering of its 
specific resistance, would modify 3V «5A just in the way that Messrs. 
Frith and Rodgersf found that it wiis modified by direct measure- 
ment. Thus all the principal phenomena of the arc, with cored and 
with solid carlx)n8 alike, may be attributable to such variations in the 
specific resistances of the materials in the gap as it has been shown 
iiiu.<f exist, together with the variations in the cross-sections of the are 
that have l>een observed to take place. Hence it is superfluous to 
imagine either a large back E.M.F. or a "negative resistance." 

• Electrical Congress* at Chicago, 1893. 

t ♦* The Resistance of the Electric Arc," * Phil. Mag.,' 1896, toI. 42, p. 407. 



Report of Hfoffnetical Obm^ations at FalrtioiUh Ohservatmy, 4ir 



Eeport of Magnetical Observations at Falmouth Observatory for 
the Year 1900. Latitude 50° 9' 0" K, Longitude 5° 4' 35" W. : 
height, 167 feet above mean sea-level. 

The Declination and the Horizontal Force are deduced from hourly 
leadings of the photographic ciu-ves, and so are corrected for the 
diurnal variation. 

The results in the following tables, Nos. I, II, III, IV, are deduced 
from the magnetograph curves, which have been standardised by 
observations of deflection and vibration. These were made with the 
Collimator Magnet, marked 66a, and the Declinometer Magnet, marked 
66c, in the Unifilar Magnetometer No. 66, by Elliott Brothers, of 
London. The temperature correction (which is probably very small) 
has not been applied. 

In Table V, H is the mean of the absolute values observed during 
the month (generally three in number), uncorrected for diurnal varia- 
tions and for any disturbance. V is the product of H and of the 
tangent of the Observed Dip (imcorrected likewise for diurnal 
variation). 

In Table YI the Inclination is the mean of the absolute observations^ 
the mean time of which is 3 P.M. The Inclination was observed with 
the Inclinometer No. 86, by Dover, of Charlton, Kent, and needles 1 
jind 2, which are 3J inches in length. 

The Declination and the Horizontal Force values given in Tables I to 
IV" are prepared in accordance with the suggestions made in the Fifth 
Iteport of the Committee of the British Association on comparing and 
reducing magnetic observations, and the time given is Greenwich Mean 
Time, which is 20 minutes 18 seconds earlier than local time. 

The following is a list of the days during the year 1900 which were 
selected by the Astronomer Royal as suitable for the determination of 
the magnetic diurnal variations, and which have been employed in the 
preparation of the magnetic tables : — 



January ... 3, 8, 9, 30, 31. 
March ... 5, 11,21,27,28. 
May ... 9, 10, 14, 21, 28. 
July ... 14, 15, 18, 22, 30. 
September 2, 7, 21, 25, 26. 
Novemljer 5, 6, 11, 16, 30. 


Febmary... 3, 6, 7, 13, 28. 

April 3, 8, 15, 22, 25. 

June 10, 11, 16,20,25. 

August ... 6, 9, 10, 23, 30. 
OctoW ... 2, 7, 13, 19, 31. 
December 3, 6, 15, 23, 24. 




EDWARD KITTO, 

Magnetic Ohseiuer, 



416 



(ia° + West.) 



Report of Magtuiiml Ob^rcatunig at 



4 



Table L— Hourly Means of DecliiuLtiou at tbe Falmonil 
on Five aeleetetl quiet Dayn b 



B^OUTK Mid. 



« j 7 



10 



11 



WineAT. 



1900, 

tarcK 
Tot. . 



I 



30 iJ 

30 -Si 

27 ^4| 
25^3 
26-8 



30-9 
30*6 
29 7 
28-0 

27 n 



Hcaub 



28 4; 2SN3 



31-2 
30-5 
20 6 
28-2 
2&'9 
27 3 



3t-4 
30-7 

20^5 
27 ft 
26-1 
27 4 



31-5 
30-8 
29-3 
27 P 

326-0 
27 4 



2d -B ! 28 -8 



28-8 



. 


1 


# 


31-3 


31*1 


30*8 


30*5 


30 'L 


20-8 


2ft 


28*9 


28-3 


\ 27-8 


27*9 


27 6 


25-8 


26-6 


2o 2 


27 3 


27-1 


26-9 


28 6 


28 a 


28*1 



30-4 

27-3 
20-7 
24 7 
26 (5 



' 30-3 

, 29*9 

' 2^-S 

, 26 -B 

1 21 -4 

' 2li-6 



30 9 
30 <4 
27 '6 
26 7 
25-5 
20*9 



32 
31-2 
2J9 7 

S8-7 
2ti*& 
27 7 



27*6 27 4 28-0 2&-4 



Qiitmti^^ 





f 


i 


J 


i 


e?:; 


29-2 


29 '2 


EO'O 


290 


29 1 


29-2 


29^2 


28*8 


use .. 


28*6 


28*5 


28-4 


28*4 


uly .. 


2*^*5 


^8-7 


28 5 


28-1 


IttgUM, 


29 -0 


29 


28-8 


28^8 


ept. .. 


28 5 


^8*4 


25*6 


28*3 



28-7 
28-4 

m^ 

27-8 
28*3 

29-1 



28 '5 
27*5 
27-5 
^■7 

27 '9 
28*0 



27^9 ' 27 

2S*4 I 25 -7 

26 4 I tb -9 

25-6 25 7 

26 *8 25 -9 

27 *6 m 8 



Mwtia 28*8: 28-8 i 28 *7 , 28'7 28 "3 27 7 I 26*8 2G'2 

I I I I I I I I 



9 


t 


/ 


* 


26-1 


26-8 


27-3 


30 1 


23 4 


2«-2 


28-0 


30 


25*7 


25-9 


27*6 


30*1 


25 1 


25*2 


26-1 


28-3 


25-6 


26-6 


29*0 


31-3 


25 '8 


26-3 


ifS*4 


31 3 


25*6 


26-0 


27-7 , 


30*2 



• Me«a of four diiji— 2nd, 7th, IStli, 31it. 



Table IL — Diurnal Inequiility of the Falmoudi 



ioiirt Mid, 



1 2 I 3 



4 6 



8 I 9 10 



11 



Slimmer meiua^ 



fc. 



t I r ' * 



-O^-'O^ -0*6 -0-5 -0-9 
I I I I 



t t $ 



-1*5 -2-4 -3*0 -3-6 



-3-2 



-1-5 



+ 1-0 



Winter 



-0 6-0*4 



-0-2 -0*2 -0-2 -0-4 -0-5 -0*9 

I I I i 



-1*4 



-1*6 



^1-0 t + 0-4 



Annuiit iiieftn^ 



f , 


/ 


I 


1 1 
' 1 ^ 1 ' 


r 


* 


p 


e 


-0'6 


-0-4 


,-0-4 

1 


_0"i -0*6 -m* I-1-5 -2 

i 1 \ 


-2 6 


-2-4 


-1*3 


+0-7 



^foh.—When the si pi is + tlip magnei pointn 



Fcdimuth Observatory for tlte Year 1900. 

Observatory, determined from the Magnetograph Curves 
eiich Month during 1900. 



417 



Noon 



10 



II Mid. 



33-2 


32-5 


32-0 


31-5 


28-0 , 


28-6 



Winter. 



34 
33-6 
33-7 
32-8 
28-3 
28-9 



33-3 
33-8 
33-8 
32-4 
27-5 
28-6 



! 31 31 -9 31 -6 



/ i / / / / 


/ 


' 


/ 


/ 


/ 


32 -6 i 32 1 32 3 31 '7 i 31 -1 


30-8 


30-7 


30-8 


30 -8 30 -8 


32-6 ! 31-5 , 310 30-7 80-5 


80-5 


801 


30-3 


80-4 I 30-7 


32 -7 ! 31 -0 29 -7 29 4 29 -7 


29-7 


29-7 


29-6 


29 -6 1 29 -8 


1 31 1 ! 29 -4 i 29 28 6 28 -4 


28-3 


27-8 


27-8 


27-7 28-0 


, 26-4 1 26-0 25-9 25 6 j 25 4 


25-2 


25 1 


25 1 


25 1 25-4 


27-9 ; 27-5 271 , 267 263 


26 -3 26 -2 


26-2 


261 


26*5 


30-6 j 29-6 29-2 288 286 


28-5 


28*3 


28-3 


28 3 


28-5 



Summer. 





- 




■ ■ - - 


-- 


— 





f 


/ 


/ 


/ 


/ 


, 




32-5 


34-1 


34-3 


33-0 


31-5 


30-3 


29-7 


32 1 


33-8 


33-6 


32 1 


30-6 


29-6 


29-0 


33-2 


34-2 


34-5 


33-8 


32*6 


30-9 


29-8 


31-7 


34-0 


34 1 


32-6 


31-2 


30-1 


29-2 


33-6 


34-8 


34 


32-7 


30-7 


29-4 


28-9 


34 


34-6 


33-2 


31 1 


29-4 


28-3 


28-3 



29-6 
28-8 
28-9 
29 1 
29 
28-8 



32 -9 I 34 -3 34 32 6 31 i 29 8 29 -2 | 29 



/ 


f 


/ 


/ 


/ 


29-5 


29-4 


29-5 


29-1 


29 


28-8 


28-9 


29-2 


29-2 


29-2 


28-6 


28-5 


28-3 


28-4 


28-6 


29-2 


29 


28-6 


28-6 


28-8 


28*9 


29 


29-0 


28-9 


29 


28-7 


28-7 


28-7 


28-7 


28-5 


29 


28-9 


28-9 


28-8 


28-8 



Declination as deduced from Table I. 

Noon 12 3 4 5 6 

, ' ' ! ' ' 

Summer mean. 



9 10 ' 11 : Mid 



+ 3-7 +51+4-8 +3-4 ; + l-8 I + 0-6 : 00:-0-2 -02 -0*3 1-0-3 i-O 4 



-0-4 



Winter mean. 



+ 20 +2-9 : + 2-6 



+ 1-6 1 + 0-6 +0-2 -0-2 

' I 

Annual mean 



-0-4 -0-5 -0-7 -0-7 ,-0-7 1-0 I 

I I i 



+ 2-9 +4-0 



t f / 1 / , r 

+ 3-7 I + 2-5 +1-2 1 + 0-4 -01 i-0-3 -0 4 



-0-5 



-0-5 -0-6 



-0-1 



to the west of its mean position. 



418 



Report of Maanetieal Observations at 



0-18000 + (Ca.S. unite). 



Table III. — Hourly Means of the Horizontal Force at Falmoutl 

on Fire selected qtiiet Days ii 



Hours 


Mid. 


1 


2 


8 ! 


* 


5 


6 


7 


8 


9 


10 


11 


Winter. 


1900. 


























Jan. .. 


671 


670 


671 


671 


678 


674 


676 


677 


675 


609 


068 


680 


Feb. .. 


672 


672 


672 


678 


673 


674 


675 


674 


678 


669 


668 


661 


March. 


679 


680 


679 


679 


679 


679 


678 


678 


675 


666 


662 


6S7 


•Oct. .. 


696 


696 


694 


695 


697 


698 


699 


698 


695 


685 


676 


671 


Not. .. 


706 


706 


706 


706 


707 


708 


708 


707 


708 


696 


602 


6M 


Dec. .. 


701 


701 


702 


708 


708 


704 


704 


704 


704 


708 


701 


699 


Means 


688 


688 


687 


688 


689 


690 


690 

t 


690 


688 


681 


676 


674 



Summer. 



r:: 


687 


686 


686 1 


1 
687 i 


686 


686 


685 


686 


683 


678 


687 


685 


683 ; 


683 , 


682 


680 


676 


672 


668 


666 1 


Juno . . 


700 


699 


697 ! 


697 1 


698 


698 


695 


692 


687 


681 ; 


July .. 


702 


701 


699 


698 1 


698 


697 


695 


693 


687 


679 1 


Aug. .. 


701 


700 


698 


698 ! 


697 


697 


693 


688 


681 


673 . 


Sept. .. 


707 


705 


704 , 


703 ' 


704 


702 


701 


697 


691 


685 


Means 


697 


696 


695 

1 


694 , 


694 


693 


691 


688 


683 


677 



668 i 


665 


666 1 


667 


675 


673 


671 


67J 


674 


680 


681 


681 



673 673 



Mean of four davs— 2iid, 7tli, 13tli, 3l8t. 



Table IV. — Diurnal Inequality of the Falmoutl 



Uoura 



Mid. 1,2 S 4 5 678810 11 



Summer mean. 



+ -00006' + -00004 + -00003 + -00002 + '00002 + -00001 - -00001 - -00004 '- '00009 - -00015 - '00019 - -OCOll 

I ' ! • . I i 



winter mean. 



+ -0U002 + -00002 



! i .1 

+ -00001 + -00002 + -00003 + -00004 + -00004 + -00004 + -00002; - -00005 :- -00010 - -ooou 



Annual mean. 



I ! ■ ' 1 ; ' ; ■ 

+ -00004 + •00003+ -00002! + -00002 + -0000:^ + -OOOO* + -00002: -00000 - '00004 - -00010 - K)0O15 - 'OOOW 

III-' • : I 



Xofe, — When the sign is + the rauliB| 



Falmouth Obaervatory for the Year lyOO. 



41U 



Observatory, determined from the Magnetograph Curves 
each Month during 1900. 



Noon 



Winter. 



662 
662 
662 
673 
696 



667 
664 
669 
681 



671 
667 
675 
688 



699 ! 703 

700 , 701 



671 
668 
679 
691 
704 
703 



076 



680 I 684 I 686 

I : 



671 
669 
681 
693 
706 
704 



687 



670 
672 
681 
693 
706 
705 



671 
678 
681 
697 
708 
705 



688 689 



672 
673 
683 
698 
708 
704 



690 



674 
674 
685 
699 
708 
704 



691 



10 



11 M 



676 
674 
684 
699 
707 
708 



673 
674 
684 
699 
705 
702 



690 690 



678 
675 
684 
699 
705 
701 



690 ! € 



Summer. 



670 


678 


687 


692 ! 


693 


691 


693 


694 


695 


694 


693 


692 


( 


670 


673 


674 


677 ' 


680 


685 


691 


694 


693 


691 


691 


691 


i 


678 


, 684 • 


691 


700 ; 


699 


700 


704 


705 


704 


703 


700 


699 


i 


680 


684 i 


689 


695 ! 


698 


698 


698 


701 


702 


704 


7a3 


708 


"i 


691 


697 


698 


700 ' 


700 


699 


699 


704 


704 


704 


703 


703 


'i 


688 


698 ' 


701 


702 


704 


702 


704 


708 


707 


707 


705 


708 


: 


680 


• 686 : 


690 


694 


696 


690 


698 


701 


701 


701 


699 


699 


6 



Horizontal Force as deduced from Table III. 



Noon 112 8 46|6i7 



9 10 II IC 



Sammer meiui. 



I 



- -00012 - 00006 - -00002 + -00002 + '00004^+ '00004 + -00006 + •00009' + -00009 + -00009 + -00007 + •00007' + I 

■ ^^ 'III i I 



Winter mean. 
••00010--00006'- -00002 -00000 + -00001 + -00002 + -00008 



+ -00004 + -00005 + -00004; + -00004 + -00004 -I- •< 



Annual mean. 



i - -0001 1 - -00006 - -00002 + -00001 + -00008 + -00008 + -0000ft + -00007 + -00007 + -OOW + -00006| + '00006 



+ •( 



is aboTC the mean. 



420 Jie^/ort of MftgnHimi OhstrvatiofiB at FalnwiUh Ob€erv<ti&r^ 



Table V. — Magnetic Intensity. Absolute Observations, 
Falmouth Observatory, 1900, 



19O0. 


G.O,^. uidunre. 1 


Hot 
HomonUl f<>rce. 


Tor 


JaiiuarT, ,,.,,,,, ^ ., ^ _ 


-186*;5 
0-18660 
^8661 
U -18670 
0'1M677 


^43503 
43474 

0*4347t; 
-43508 


l^phrqftiry < , ^ . . . . <, , 


Mftrch ... ^ ,..-*..».- . 


Anftl , , • 


Elv :::.:::::.::;.; : 


Juue *.,.*.. - 

JuIt..,,..,.... 


0^8682 1 0^434*53 
O^lSesO 1 0*43458 
0-18681 ' 0*43.i60 
O'lmm i 0-43495 
0-18683 ' 0-43489 
0*18^6 U-4349© 
0^8696 ' 4340S 


AUKUSt . ..***■■.« .1 ^ mi. 


Sf^t^nibeP . . » . ...... . , 


October ,.......>...., 


^^OTenaber ,,,,»,-, ^ »♦ . 


B<Nreinber 


O-1B680 -tillftS 






} 



Table VI. — Magnetic Inclination. Absolute Observations. 
Falmouth Observatory, 1900. 



Month. 



Mean. 



Month. 



January 10 66 46-8 

24 66 46-6 

31 , 66 46 -7 

66 46-7 

February 10 66 45 9 

21 66 46-6 

28 66 46-0 

66 46-2 

March 10 | 66 46 6 

21 66 46-6 

30 66 45-5 

I 66 46-2 

April 10 ,66 47-0 

20 66 45-8 

28 66 45-5 

I 66 46 1 

May 10 ! 66 47 '2 

21 66 45-7 

30 66 44-4 

66 45-8 

June 11 66 44*8 

20 66 43-6 

29 ! 66 44-9 

66 44-4 



July 



August 



10. 
20. 
30. 



12. 
26. 
31. 



Mean. 

66 43 7 
66 44*4 
6643-9 

66 44-0 

66 43-9 
66 44-3 
66 45-0 

66 44*4 



SeptemberlS 66 44-4 

19 66 44-3 

66 44-4 



8. 
20. 
22. 
30. 



October 8 66 44-3 

, 66 44-9 

66 45 -O i 

66 46-3 ' 

66 451 

November 10 66 45-7 

21 66 43-9 

29 66 43-8 ; 

66 44-5 i 



December 11 66 43 -5 

19 66 46-9 

31 '66 43-7 



66 44-4 



THE NATIOJfAL PHYSICAL LABORATORY. 



Report on the Ohservato}*y Department for the Year 
endhig December 31, 1900. 



The work at the Kew Observatory in the Old Deer Park at Richmond, 
now forming the Observatory Department of the National Physical 
Laboratory, has been continued during the year 1900 as in the past. 

This work may be considered under the following heads : — 

I. Magnetic observations. 

II. Meteorological observations. 

III. Seismological observations. 

IV. Experiments and Researches in connexion with any of the 

departments. 
V. Verification of instruments. 
VI. Rating of Watches and Chronometers. 
VII. ^liscellaneous. 

I. Magnetic Observations. 

Tlie Magnetographs have been in constant operation throughout 
the year, and the usual determinations of the Scale Vahies were made 
in January. 

The ordinates of the various photographic ciu^'es representing 
Declination, Horizontal Force, and Vertical Force were then found 
to l)e as follows : — 

Declinometer : 1 cm. = 0° 8' -7. 

Bifilar, January, 1900, for 1 cm. 5H = 0-00051 C.G.S. unit. 

Balance, January, 1900, for 1 cm. 8V = 0*00049 C.G.S. luiit. 

The distance between the dots of light upon the vertical force 
cylinder having become too small for satisfactory registration, the dots 
were separated on June 20 by slightly altering the position of the 
zero mirror. 

The curves have been quite free from any large fluctuations ; indeed, 
no unusual disturbance has been registered for some time past. The 
principal variations that were recorded during the year took place on 
the following days : — 

Januiiry 19th-20th ; March 8th-9th and 13th ; May 5th. 

The hourly means and diurnal inequalities of the magnetic elements 
for 1900, for the quiet days selected by the Astronomer Royal, will be 
found in Appendix I. 



422 The Xational Pliyidcal LabaixUory. 

A correction has been applied for the diurnal variation of tempeni- 
ture, use being made of the records from a Bichard thermograph as well 
jis of the eye observations of a thermometer placed under the Vertical 
Force shade. 

The mean values at the noons preceding and succeeding the selected 
quiet days are also given, but these of coiurse are not employed in 
calculating the daily means or inequalities. 

The following are the mean results for the entire year : — 

Mean Westerly Declination 16"* 52'-7 

Mean Horizontal Force 018428 C.G.S. unit. 

Mean Inclination 67' ir-8 

Mean Vertical Force 0-43831 C.G.S. unit. 

Observations of absolute declination, horizontal intensity, and incli- 
nation have been made weekly as a rule. 

A table of recent values of the magnetic elements at the Observa- 
tories whose publications are received at Kew will be found in 
Appendix Ia to the present Report. 

A course of magnetic instruction was given to Captain Denholm 
Fraser, R.E., charged with a magnetic survey of India, and facilities 
were afforded him for making experiments with a view to improving 
the instrumental outfit for the survey. 

A new magnetic hut was erected early in the year by Mr. Eldridge. 
It is larger and better lighted than the old hut, and has proved very 
useful. 

IL Meteorolocjical Observatioxs. 

The several self-recording instruments for the continuous registra- 
tion of Atmospheric Pressure, Temperatiu'e of Air and Wet-bulb, 
Wind (direction, pressure and velocity), Bright Sunshine, and Kain 
have been maintained in regular operation throughout the year, and the 
standard eye ol)servations for the control of the automatic records 
have been duly registered. 

The tabulations of the meteorological traces have been regularly 
made, and these, as well as copies of the eye observations, with notes 
i)f weather, cloud, and sunshine, have been transmitted, as usual, to the 
Meteorological Office. 

With the sanction of the Meteorological Council, data have been 
supplied to the Council of the Royal Meteorological Society, the 
Institute of Mining Engineers, and the editor of 'Symons* Monthly 
Meteorological Magazine.' On the initiative of the Meteorological 
Office, some special cloud observations have l>een made in connection 
with the International scheme of balloon ascents. 

Elecitmjraph, — This instrument worke<l generally in a satisfactory 
manner during the year. 

The small glass l^eaker mentioned in last year's Keport is still 



Rrpoi't oil the Obscrvatoi'i/ DcpaHiiieiU, 423 

employed, and by removing the siilphunc acid at regular periods — 
generally fourteen or fifteen days — the troubles previously experienced 
with the " setting " of the needle and with the shift of zero has been 
largely overcome. 

No systematic use has been made of the thirty-six Clark cells men- 
tioned in the 1898 Keport, but they have been employed to check the 
scale values of the two portable electrometers. 

Scale-value determinations of the electrograph were made on April 2, 
July 14, and October 25, and the potential of the battery has been 
tested weekly. Forty cells only have been employed during the year, 
gi^ang about 30 volts. 

With a view to promoting luiiformity in procedure, the Superin- 
tendent, at the suggestion of the Meteorological Office, had an inter- 
view with Mr. C. T. R. Wilson, F.R.S., and Mr. W. Nash, of Greenwich 
Observatory, who were shoi^Ti the electrograph arrangements and the 
means adopted for standardising the curves. The stoppage this 
entailed in the working of the instrument was utilised in giving it a 
thorough cleaning. A new bifilar suspension was also fitted to the 
needle, and the wire leading from the can to the electrometer was 
liedded in paraffin wax in hopes of improving the insulation. 

Impedio}is,-^\ii coippliance with the request of the Meteorological 
Council, the following Observatories and Anemograph Stations have 
been visited and inspected : — North Shields, Glasgow, Aberdeen, 
Alnwick Castle, Deerness (Orkney), Falmouth, and Fort William, by 
Mr. Baker; and Radcliife Observatory (Oxford), Stonyhurst, Fleet- 
wood, Armagh, Dublin, Valencia, and Yarmouth, by Mr. Constable. 

III. Seismolo<;ical Observations. 

Professor Milne's " unfelt tremor " pattern of seismograph has been 
maintained in regular operation throughout the year; particulars of 
the time of occiu:rence and the amplitude in seconds of arc of the 
largest movements are given in Table I, Appendix III. 

The " disturbance " on January 20 was particularly noticeable. 

The movement was the largest that has yet been fully recorded at 
the Observatory, the maximum amplitude being 15 mm., or 12*6 seconds 
of arc. The next largest disturbance was on October 29, with a maxi- 
mum of 12 mm., or 9*5 seconds of arc. 

The action of the boom was not altogether satisfactory during 
August and September, and on September 27 the old boom was 
Tcplaced by a new one of standard pattern. The balance weights are 
at 117 mm. and the tie at 127 mm. from the cup end of the boom. 

The point of the Ijearing pivot on the stand was also improved. 

A detailed list of the movements recorded from January 1 to 
December 31, 1900, was made and sent to Professor Milne, and will 
be foimd in the * Keport' of the British ^Vssociation for 1901^ " S^^yssoms^- 
logical Investigations Committee's Report." 



424 The Nati(ynal Physical Ldbaixavry. 

During October a Milne seismograph, Na 31, intended to be set up 
at the University Observatory, Coimbra, was fitted up in the Beismo- 
graph room, at the same height and in the same N. — S. direction as the 
Kew Instrument, and a series of comparisons were carried out till the 
end of the year. Several interesting features were noticed, and the 
results have been embodied in a paper by the Superintendent. 



IV. Experimental Work. 

Fog and Mist. — The observations of a series of distant objects, 
referred to in pronous ' Reports,' have been continued. A note is taken 
of the most distant of the selected objects which is visible at each 
observation hour. 

Atmospheric Electricity. — The comparisons of the potential, at the 
point where the jet from the water-dropper breaks up, and at a fixed 
station on the Observatory lawn, referred to in last year's * Report,* 
have been continued, and the observations have been taken since 
March on every day when possible, excluding Sundays and wet days. 
The ratios of the " curve " and the " fixed station " readings have bcjen 
computed for each observation, and these have thrown considerable 
light upon the action of the self-recording electrometer, especially with 
reference to its insulation. Some direct experiments have also been 
made on this point. 

The reservoir holding the supply of water for the water-dropper of 
the self-recording electrometer is supported upon six large " Mascart " 
insulators, and it was thought that perhaps this system of insulating 
the tank could be improved upon. 

A quantity of fine paraffin wax, with a high melting point, was 
procured from Price's Candle Company, Limited, in rectangular blocks, 
and a number of cylinders of sulphur were cast at the Observatory. 
Three similar water tanks were supported upon three wax blocks, 
three sulphur blocks, and three Mascart insulators respectively. Each 
received a similar definite charge, and the rate of loss of charge was 
observed. 

The observations — which are to be regarded only as preliminary — 
extended through May, Jime, and July, under various hygrometrie 
conditions. The sulphur and paraffin when new and clean gave much 
the best values, but after the lapse of a few weeks the rate of loss 
became very similar for all three species of insidator. The deteriora- 
tion was apparently due to accumulation of dust, i^c. The pro^^sion 
of a hood or cover to the sulphiu* and paraffin blocks would undoubtedlv 
improve the permanency of their insiUating qualities. 

Platinum Thermometry. — The paper by the Superintendent, referred 
to in last year's Report, has been published in the Royal Society's 
* Proceedings,' vol. 67, p. 3. 



Report on, the Observataty DepartvieiU. 



425 



V. Verification of Instruments. 

The subjoined is a list of the instruments examined in the year 

1900, compared with a corresponding return for 1899 : — 

Number tested in the year 
ending December 31. 

1899. 1900. 

Air-meters 6 9 

Anemometers 23 I 

Aneroids 175 197 

Artificial horizons 9 27 

Barometers, Marine 92 139 

„ Standard 85 57 

„ Station 15 23 

Binoculars 404 963 

Compasses 43 51 

Deflectors 6 1 

Hydrometers 241 173 

Inclinometers 9 17 

Photographic Lenses 160 136 

Magnets 3 1 

Telescopes 561 1,345 

Eain Gauges 19 4 

Eain-measuring Glasses 44 29 

Scales — 1 

Sextants 876 813 

Sunshine Recorders 6 3 

Theodolites 24 12 

Thermometers, Avitreous or Immisch's 5 — 

Clinical 16,020 20,476 

„ Deepsea 19 83 

„ ffighEange 62 40 

„ H3rpsometric 39 66 

„ Low Range 103 33 

„ Meteorological 2,892 2,786 

„ Solar radiation — 2 

Standard 104 61 

Unifilars 5 5 

Vertical Force Instruments 1 14 

Declinometers — 1 

Total 22,051 27,569 



Duplicate copies of corrections have been supplied in 56 case^. 
VOL. LXVIII. *i ^ 



42G The Natimiai Pht/^kal Lah/mim'p, 

The numbor of inatruments rejecte<l in 1809 and 1900 on acoount 
ejcce&sfive error, or for other rensons, was m follows :^- 

Thermometers, clinical ,*., .*».-. 149 IIG 

„ ordinary meteorological ,.. 78 7& 

Sextants 151 122 

Telescopes ..,. , *,..,,,.., 49 IIG 

Binoculars 21 31 

Varioui 14 SS 

Four Standard Thermometers Iiavc Wu construct^ during the 
year. 

There were at the end of the year in the Observatory, undergoing 

verification, 16 Barometers, 285 Thennometera, 15 Sextants, 250 Tele- 
scofjes, fiO Binoculars, 2 Hydrometers, 4 liain Pleasure?, 2 Kain Gauges, 
and 4 Uuiiilar Magnetometers, 

VL Eating of Watchks and CuRoxMMETEKa 

The nuniljer of watches sent for trial this year is sRghtly less th^n 
m 1899, the total entries l>eing 403, as compared with 469 in the pre- 
ceding year. 

The "especially good" class A certificate was obtained by 98 
movements. 

This is a marked increase on the number obtained in 1899, and the 
general performance has been decidedly better. 

The following figures show the percentage number of watches 
obtaining the distinction " especially good," as compared to the total 
number obtaining class A certificates : — 

Year 1896. 1896. 1897. 1898. 1899. 1900. 

Percentage " especially good " 16*6 305 280 221 266 35-4 

The percentage is thus higher than in any previous year. 

The 403 watches received were entered for trial as below : — 

For class A, 320 ; class B, 60 ; and 23 for the subsidiary trial. Of 
these 21 passed the subsidiary test, 55 failed from various causes to 
gain any certificate, 50 were awarded class B, and 277 class A certifi- 
cates. 

In Appendix II will be found a table giving the results of trial of 
the 51 watches which gained the highest number of marks during 
the year. The highest place was taken by Mr. A. E. Fridlander, of 
Coventry, with the keyless going-barrel Karrusel lever watch, No. 
25,582, which obtained 90' 1 marks out of a maximum of 100. 

This is the first English lever watch to reach the 90 marks limit, and 
its performance is the best since 1892. 
^ ^'"'ine Chronometers, — Diuing the year, 53 chronometers have beea 



Report on the Observatory Department. 427 

entered for the Kew A trial and 1 for the B trial. Of these 44 gained 
A certificates, 1 a B certificate, and 9 failed. 

The mean-time chronometer Arnold 86, and the hack chronometer 
Molyneux 2123 have been cleaned and re-timed. 

VII. Miscellaneous. 

Commissians, — The work under this heading has been of a very 
varied character during the year. The following instruments have 
been procured, examined, and forwarded to the various Observatories 
on whose behalf they were purchased : — 

For Lisbon and Portuguese W. Africa, a transit theodolite, a 
declinometer, a dip circle with two needles, a centre-seconds 
watch, and two chronometers. 

For Mauritius, a Mason's hygrometer, an ordinary maximiun and 
two solar maximum thermometers. 

For the Central Physical Observatory, St. Petersburg, and the 
Baron Toll Expedition : A dip circle with six needles, two 
prismatic compasses, two aneroid barometers, a Robinson cup 
anemograph, a chronometer, and a deck watch. 

For de Bilt (Utrecht), a vertical force magnet. 

Palmer. — Prepared photographic paper has been supplied to the 
Observatories at Hong Kong, Mauritius, Lisbon, Toronto, St. Peters- 
burg, Stonyhurst, Oxford (Radcliffe) ; and through the Meteorological 
OfHce to Aberdeen, Fort William, and Valencia. 

Photographic paper has also been sent in quarterly instalments to 
the India Office for use at Colaba (Bombay), Calcutta, and Madras. 

Amiimjraph and Sunshine Sheets have also been sent to Hong Kong, 
Mauritius, and St. Petersburg ; Papier Saxe to Coimbra ; and Seismo- 
graph rolls to Mauritius. 

Pendulum ObservtUions, — In June, Mr. Putnam, of the U.S. Coast and 
Gdodetic Survey, swung half-second pendulums in the wooden room in 
the basement. 

Lih'anj, — During the year the library has received publications 
from — 

19 Scientific Societies and Institutions of Great Britain and 

Ireland, 
96 Foreign and Colonial Scientific Establishments, as well as from 

several private individuals. 

The card catalogue has been proceeded with. 

Audita d;t\ — The accounts for 1900 have been audited by Messrs. W. 
B. Keen and Co., chartered accountants. The balance sheet is ap- 
pended. 



428 



Tlic Natioiiol Pht/sical Laboralorj/, 



PERiSONAL KSTABLISHMENT* 

The staff employed is as follows : — 

It T. GUzebrook, Sc.D., F,KS., Director of the Laboratory. 

C. Chree, Sc.D., F,E,S,, Superintendent of the Obsert-atory* 

Department* 

T, W» Baker, Chief Assistant. 

K G. Constable ] 

W. Hugo 

J Foster », Benior AfiaiatanU in the Observatory 

T, Girnter Depirtment, 

W. J, Boxall 

G. E. Bailey 

E. Boxall 

G. Badderly J 

Eight other Assistanta. 

A Caretaker and a Housekeeper are also employed. 

In addition to the above, Dr. J. A. Harker has been employed in the 
capacity of an Assistant in the Laboratory. 

(Signed) R. T. GLAZEBROOK, 

Director. 
List of Instruments, Apparatus, &c,, the Property of the National 
Physical Laboratory Committee, at the present date oat of the 
costody of the Director, on Loan. 



^ Junior Assistants. 



To whom lent. 



Executors of G. J. 
Symons, F.B.S. 

The Science and Art 
Department, South 
Kensington. 

Professor W. Grylls 
Adams, F.B.S. 



Lord Bayleigh, F.B.8. 

Mr. P. Baracchi 
(Melbourne Uni- 
versity). 



The Borchgreyink. 
Newnes Antarctic 
Expedition. 

C. T. B. Wilson, 
P.B.8. 



Articles. 



Portable Transit Instrument 

Articles specified in the list in the Annual 
Beport for 1803 

Unifilar Magnetometer, by Jones, No. 101, 

complete 

Pair 9-inch Dip Needles with Bar Magnets . • . 

Standard Barometer (Adie, No. 655) « . 

Unifilar Magnetometer, by Jones, marked 
N.A.B.C., complete 

Dip Circle, by Barrow, with one pair of 
Needles and Bar Magnets 

Tripod Stand 

Dip Circle, by Barrow, No. 24, with four 
Needles and Bar Magnets 

Electrograms for 1897 



Date 

of loan. 



1869 



1876 



1883 
1887 

1885 



1899 

1899 
1899 



1898 
1899 



Report on tlie Observatory Department 



429 



05 



< 



o 
o 



1^ 



«c 




S5ii 






1 


1 


Eh 


^ 


<5 


w^ 


J2; 




piq 




a 




H 





a 

H 

9 

M 



© 
© 



. r3 






i 



I 



s s s 

l> o ••• 

of fH i-T 



t* O •* 
lO iH 00 



0^ q^ 






1 






§ 1 
11 


g i^ Oh h-j* 

- 1 rsi'S 




ji> g gs 8 £ 


S = 


g-^ H W 


^ S 



m a. 



430 


The Noilatuil Fhtjdcal £aho}\itor^. 


~ 


^*- 


o o 


*o 


(p-i 


1 


-1 


i 1 






J 



^4 



1A W 



S 2 r: 



O 



w 3 

S £ 

w o 



1 = 






I "s 1 5! 

2 sr^ 



i ^ I f ^ m 

'S *o 5e 'H *^ "3 fl 



S 



u ' 






j?^ -t •= 



i § 

-J 

n g 

1 ^ 



£4 









s 



'^ ' I; 



.-** = 0-5 



S ^ 



13 £ 






c«)S 



t 



s 

8 

PQ 



Report on the Observatort/ Department. 



431 



o 

Ci 



50 






s 



o 


«H 




»H 


»o 


Cd 




^ 


•H 


QQ 




s 




■mf 




^ 



O O O 00 




i. 



^" a -I 

I 1.1 4 I 3 
•Ik's <l« § 

1 § J 1 1 

g D w I £ g 



« i-i iH ;0 CO 




a> CO to ^ 99 
^ rH rH rH 




SS^S^ 





1 



a 



'S^ 



o 

^ 



«^ 



CD O 
» O 

of 



99 

CO 



i-H O 



o o 

CO O 



^ 






c 

» o