(navigation image)
Home American Libraries | Canadian Libraries | Universal Library | Community Texts | Project Gutenberg | Children's Library | Biodiversity Heritage Library | Additional Collections
Search: Advanced Search
Anonymous User (login or join us)
Upload
See other formats

Full text of "The eruption of Krakatoa, and subsequent phenomena"

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/ 



HARVARD UNIVERSITY 




GEOLOGICAL SCIENCES 

LIBRARY 

From the library of 

Jay Backus Woodworth 



Transferred to 

CABOT SCIENCE LIBRARY 

June 2005 




WILLIAM U. SWAN. 



THE ERUPTION OF KRAKATOA, 



AXD 



SUBSEQUENT PHENOMENA. 



EXPLANATORY OF COLOURED FRONTISPIECE. 



These chromo-lithographs are reproduced from a series of six crayon sketches 
made on the bank of the Thames, a little west of London, on the evening of 
November 26th, 1883, by Mr. W. Ascroft, of Chelsea. 

They represent the general colouring of the western sky from shortly after 
sunset (3h. 57m. p.m.) to the final dying out of the after-glow at about 5.15 p.m. 

The increase of light after the cessation of ordinary twilight — that is to say, 
between Nos. 2 and 4 — is very marked, and the gradual change iu the tone of 
Nos. 3, 4, 5, and 6 very instructive. 



TwiLIGliT AND ArttRGLOW tFft f CHLLSCA, LONOON. 

Nov 2Q'r 1883. 



I 



V 



'^ 





r 



THE ERUPTION OF KRAKATOA, 



AND 



SUBSEQUENT PHENOMENA. 



REPORT OF THE KRAKATOA COMMITTEE 



OF THE 



ROYAL SOCIETY. 



VIZ.: — 



Abkrcromby, The Hon. Ralph. 
Archibald, E. Douglas, 
BoNNEY, Pbof. T. G., F.R.S. 
Evans, (the late) Sm F. J., F.R.S. 
Geikie, De. a., F.R.S. 
JuPD, Prof. J. W., F.R.S. 
LocKYffii, J. Norman, F.R.S. 



Russell, The Hon. F. A. Rollo. 
Scott, R H., F.R.S. 
Stokes, Prof. G. G,, Fres. R.S. 
Strachey, Lt.-General, R.E., F.R.S. 
Symons, G. J., F.R.S., Chairman. 
Wharton, Capt. W. J. L., RN., 
F.RS. 



Edited by G. J. SYMONS, F.R.S. 



LONDON: 
PRINTED BY HARRISON AND SONS, ST. MARTIN'S LANE, W.C, 

AND PUBLISHED BY 

TRt)BNER & Co., 57 and 59, LUDGATE HILL. 

1888. 
Price Thirty Shillingt. 



v.. 






SPEC 






PREFATORY AND HISTORICAL. 



The extremely violent nature of the eruption of Krakatoa on August 26th-27th, 
1883, was known in England very shortly after it occurred, but it was not until a 
month later that the exceptional character of some of the attendant phenomena was 
reported. Blue and green suns were stated to have been seen in various tropical 
countries ; then came records of peculiar haze ; in November the extraordinary 
twilight glows in the British Isles commanded general attention, and their probable 
connection with Krakatoa was pointed out by various writers. 

At the meeting of the Royal Society, on December 13th, a paper by Mr. Scx)tt, 
and a note by General Strachby, gave the first details of the great air- wave, and 
indicated its nature and extent. 

On January 10th, 1884, papers by Commander the Hon. F. C. P. Vereker and 
by Mr. Kennedy, BLB.M.'s Consul at Batavia, describing the remarkable changes in 
the physical configuration of the district, were read before the Boyal Society. In 
the course of the discussion upon them, it was suggested that it would be well to 
collect and coordinate all the information obtainable respecting the mruption; and 
the President (Professor Huxlet) promised that the subject should be brought 
before the Council. 

On January 17th, the Coundl passed the following resolution : — ^'* That a 
" committee, to consist of Sir F. Evans, Prof. Judd, Mr. Nobman 
" Locrteb, Mr. R. H. Scott, General Strachey, and Mr. G. J. 
** Stmons, with power to add to their number, be appointed, to collect 
'' the various accounts of the volcanic eruption at Krakatoa, and 
*' attendant phenomena, in such form as shall best provide for their 
'* preservation, and promote their usefulness/' 

The first meeting of the Committee was held on February 5th, all the members 
being present. It was resolved that a letter inviting assistance should be prepared 



[ iv J 

for inflertion in ' The Times ' and other periodicak. The following is a copy of that 
letter : — 



"THE KRAKATOA ERUPTION, 

'' Sir, — ^The Coundl of the Boyal Sociefy has appointed a committee for the 
purpose of collecting the various accounts of the volcanic eruption at Erakatoa, and 
attendant phenomena^ in such form as shall best provide for their preservation and 
promote their usefulness. The committee invite the conmmnication of authenticated 
facts respecting the fall of pumice and of dust, the position and extent of floating 
pumice, the date of exceptional quantities of pumice reaching various shores, 
observations of unusual disturbances of barometric pressure and of sea level, the 
presence of sulphurous vapours, the distances at which the explosions were heard, 
and exceptional effects of light and colour in the atmosphere. The committee will be 
glad to receive also copies of published papers, articles and letters bearing upon the 
subject. Correspondents are requested to be very particular in giving the date, 
exact time (stating whether Greenwich or local), and position whence all recorded 
facts were observed. The greatest practicable precision in all these respects is 
essential. All communications are to be addressed to — 

" Your obedient servant, 

"G. J. SYMONS, 
'^ Chairman, Ejukatoa Conmiittee. 
'' Royal Society, Burlington House, 

'* February 12th, 1884." 



A secretary also was appointed who attended daily at Burlington House 
for about twelve months, searching many hundred periodicals, and parts of 
* Proceedings,' ^ Transactions,' &c., copying out and classifying the various state- 
ments, as well as attending to the correspondence received in reply to the published 
invitation. 

At the meeting on March 27th, 1884, a letter was read which had been received 
from the Royal Meteorological Society, stating that on January 16th that Society had 
appointed a committee to investigate the cause of the remarkable sunrises and 
sunsets, and had already issued circulars of inquiry over the greater part of the globe, 
and suggesting that therefore that branch of the inquiry should be left to them. 
Eventually it was arranged that all the data collected by the Royal Meteorological 
Society should be handed over to the Erakatoa committee, and that the members of 
the committee of the Royal Meteorological Society should be made members of the 
Erakatoa committee. The Hon. Ralph Absbobombt, Mr. E. Douglas Abchibald, 
and the Hon. F. A. Rollo Russell, were so elected. 



[ y ] 

Coloured drawings of the twilights were submitted to the committee on March 
27th, 1884, by Mr. J. S. Dyason, and on June I9th, 1885, by Mr. W: Ascjeoft ; six 
of those submitted by the latter artist have been reproduced as a Frontispiece to this 
volume. 

At the meeting on June 18th, 1884, Dr. Geikie, and on November 20th, 1884, 
Prof. BoNNEY, were added to the committee. 

At the end of November, 1884, it was considered expedient to commence the 
discussion of the great mass of data collected, and it was divided into five portions, 
each going to a separate sub-committee as follows : — 

GEOLOGICAL. 

Including descriptions of the Eruption, Earthquakes, and the Geological features 
relating to Dust and Pumice- 
Prof. JuDD, Dr. Geikib, 
Prof. BoNNEY, Mr. E. H. Scott. 

METEOEOLOGICAL. (A.) 

Including Air- Waves, Sounds, and the geographical distribution of Dust and 
Pumice — 

General Strachey, Prof Stokes, Mr. R. H. Scott, 

METEOROLOGICAL. (B.) 

Including Twilight Effects, Coronal Appearances, Cloud Haze, Coloured Sun, 
Moon, &c. — 

Mr. E. Douglas Archibald, Mr. J. Norman Lockyee, 

Hon. RoLLO Russell. 

SEISMIC SEA WAVES. 

Sir F. Evans (and subsequently Captain Welarton), General Strachey. 

TERRESTRIAL MAGNETISM AND ELECTRICITY, 

The Kew Committee. 
(G. M. Whipple, B.Sc, Superintendent.) 
The extraction of data being then nearly finished, it was not considered necessary 
to retain the services of the secretary, and all the routine work for the subsequent 
two years was conducted by the Chairman. 

On the death of Sir F. Evans, the President and Council of the Royal Society 
nominated Captain Wharton as a member of the committee, and he has completed 
the investigation of the Seismic Sea Waves. 



[ vi ] 

Thus it will be seen that 28 months elapsed between the distribution of the data 
to the various sub-committees and the completion of the report and its transmission 
to the Council. But it is to be remarked that the optical phenomena did not entirely 
fade from view until the early part of 1886, and that besides the great mass of 
material originally distributed, a constant flow of additional literature, including the 
very valuable report by Mr. Yeebeek, has been received and transmitted to the 
writers of the various Parts. 

As regards the mass of material, it may be mentioned that it has included — 

Barograms firom 50 observatories, 
Magnetograms from 1 1 „ 
Tidal Becords ,, 50 stations. 

Between 300 and 400 letters have been received, most of them enclosing bulky 
reports. Many, being written in foreign languages, have required translation, and 
all have required the conversion of their local times into 6.M.T., and of course the 
answering and forwarding of these letters has involved much clerical labour. 

The printed literature on the subject has been very extensive, as is shown by the 
appended list of books and papers consulted, and the work altogether has been very 
heavy, for it has not only extended back to the year 1500, but it has ramified 
through many branches of physics, and has involved extensive correspondence with 
all parts of the globe. 

In the spring of 1887 the MS. was completed and submitted to the Council of 
the Boyal Society, together with estimates of the cost of publication. The Council, 
while of course expressing no opinion upon the work, authorised the committee to 
proceed with the printing. 

I hope that I may here be permitted on behalf of the committee to acknowledge 
the constant and great help which we have received throughout from the President, 
Ofl&cers, and Council. 

The volume itself wiU show the amount of heavy work done by the various 
authors, and who is responsible for the several arguments and opinions. I wish, 
however, to point to one unusual feature, viz., the hundreds of references which 
are given. The committee's first duty (and desire) was to collect facta This duty 
we have all tried to discharge, and we have not only collected the facts, but have 
done our utmost to enable everyone to verify theiu. 

G. J. Symons. 

Burlington House, W., December^ 1887. 



[ vii ] 



List of some op the Principal Books and "Papers published i^especting 
THE Phenomena reported upon in this Volume. 



Aitken, John. The Remarkable Sunsets. 'Proc. Royal 
Society of Edinbui^h,' vol. zii. 

Second Note on the Remarkable Sunsets. * Proc. 

Royal Society of Edinburgh,' voL xii 

AxLffot, A. . Sur les cr6pu8cules color^ 'Coraptes 

Rendus/ vol zcviii., p. 164. 
JkTWLgo, P. The Comet : Scientific Notices of Comets in 

general, translated by Col. Gold. 1833. 
Aaainaim, Dr. B. Die Dammerungs-Erscheinungen und 

der braune Ring um die Sonne im dies-jahrigen Winter 

nnd Friihjahr, nach Beobachtungen in Magdeburg und 

im Harze. * Meteor. Zeita,' vol. i., pp. 196-198. 1884. 
B aixd, Vajor, B.B. On the Tidal Disturbances caused by 

the Volcanic Eruptions at Java. * Proc. Royal Soc,' 

vol. xxzvi., pp. 248-253. 

Report on the Volcanic Eruptions at Java in 

August, 1883. Sm. fol., Dehra Dun. 1884. 

Bealixy, J. T. The Java Eruption and Earthquake Waves. 
•Nature,' vol. xxix., pp. 30-32. 188a 

Beaold, ProflBMor von. Ueber die ausserordentlichen Dam- 
merungs-Erscheinungen. * Zeits. fUr Met.' (1884), p. 72. 

Biffffs, A. B. Mercury (Hobart Town). March 19, April 
3, July 12 and 22, 1884. 

Bishop, 8. E. The Equatorial Smoke-Stream from 
Krakatoa. ' Hawaiian Monthly,' May, 1884. 

Origin of the Red Glows. 'American Met. 

JourV July ftnd August, 1886. (Printed also as one 
of the Prize Essays in ' History and Work of the 
Warner Observatory,' voL i. 1887.) 

Bouquet da la Grye. Sur la propagation des lames pro- 
duites par T^ruption des volcans de Java. (Ao&t, 1883.) 
* Comptes Rendus,' voL xcvii, pp. 1228-1230. 

BoixUUa O. O. Water Waves from Krakatoa. ' Science, 
voL iii., pp. 776, 777. 1884. 

Br6oii «t Korthals. Sur r6tat actuel du Elrakatau. 
^ Comptes Rendus,' vol. xciz., pp. 395-397. 1884. 

Bni«mans, 8. J. Natuurkundige verhandeling over een 
Zwavelagtigen Nevel den 24 Juni, 1783, in de Pro- 
vintie van Stad en Lande en naburige landen waar- 
geuoiuen. 8vo., Groningen. [1783.] 



Burton, Captain, B. F. The Volcanic Eruptions of Ice- 
land in 1874 and 1875, with two maps of Icelaud. ' Proc. 

Royal Society of Edinburgh,' Session 1875-76, vol. ix. 
COark, J. Edmund. The Recent Sky-Glows. Warner 

Prize Essay, 'Hist and Work of the Warner Obs.,' 

voL I 1887. 
Oomu, A. Observations relatives a la coiu-onne visible 

actuellement autour du SoleiL 'Comptes Rendus,' 

vol. xciz., pp. 488-493. 1884. 
Cotteau et Korthals. Mission Fran^aise aii Krakatau. 

*Compte Rendu, Soc. G6og.,' No. 15, pp. 452-455. 1884. 
Dall, W. H. A new Volcano Island in Alaska. ' Science, 

vol. iii., pp. 89-9a 
Daubree. Ph^nomdnes volcaniques du d6troi t de la Sond e, 

examen min6ralogique des cendres. ' Comptes Rendus,' 

vol. xcvii, pp. 1100-1105(1883); voL xcviiL, p. 1303 

(1884). 
Davidson, Geo. Notes on the Volcanic Eruption of Mt. St 

Augustin. ' Science,' vol. iiL, pp. 186-189, and 282-286. 
Davy, lCari»- Sur les oscillations barom^triques. ' Com ptes 

Rendus,' voL xcviii., pp. 246-248. 1884. 
De lok Bive. Note sur la seconde coloration du Mont 

Blanc. ' Bibliothdque Universelle,' Nouvelle S^rie, 

voL xxiii., p. 383 ; vol. xxiv., p. 200. 1839-40. 
Dellale, Dr. Les secousses de tremblement de terre a la 

Reunion et k Maurice comme consequence de I'^ruption 

volcanique du d^troit de la Sonde. 'Bull. Soc. G6og. 

pp. 524-526. 1883. 
Deaoroiz, Leon. L'oecillation atmosph^rique produite par 

r^ruption de Krakatoa. ' L' Astronomic,' 3rd Ann6e, 

pp. 183, 184. 1886. 
Diller, J. S. Report on Atmospheric Sand-dust from 

Unalaska. ' Nature,' voL xxx. (1884), pp. 91-93. 
Divers, Trot, B. The Remarkable Sunsets. 'Nature, 

vol xxix. (1884), pp. 283, 284. 
Doom, K. O. van. (Captain of ffydrograaf). The Eruj - 

tion of Krakatoa. 'Nature,' voL xxix. (1884), pp. 268, 

269. 
Dufour, Ch. Les lueurs cr^pusculaires de I'hiver 1883- 

1884. ' Bibliothdque Univer.,' 15th Fev., 1885. 



[ viii J 



Bufour, Ch« Sur les luears cr^pusculaires et aurorales de 

rhiver de 1883-4. * Ck>mpte8 Bendus,' voL xcviii., pp. 

617-620. 1884. 
Faye. Sur les troubles physiques de ces demiers temps. 

*Comptes Rendus,' vol. xcviii., pp. 179, 180. 
Flgnier, Ii. Les lueurs cr^pusculaireB de 1883-84. 

' L'ann^e Scieutifique et Industrielle,' 1884 and 1885. 
F[lammarion], O. Les illuminations cr6puaculaires. 

* L'Astronomie.' 3rd ann6e, pp. 19-27. 1884. 
Forbes, H. O. The Volcanic Eruption of Krakatau, 

* Proc. Royal Geog. Soc,' voL vi., pp. 142-152. 1884. 
Forbes, J. D. On the Colour of Steam under certain cir- 
cumstances, * Trans. Royal Soc., Edin.' 4to., 1839. 

Forel, F. A. Sur quelques ph6nomdnes lumiueux parti- 
culiers observes en Suisse autoar du SoleiL ' Comptes 
Rendus; vol. xcix., pp. 289, 290, 423-425. 1884. 

LaCouronne Solaire de V6i6 de 1884. *Biblio- 

th^que Universelle,' 15th September, 1884. 

Bruits souterrains entendus le 26 AoAt^ 1883, 



dans I'tlot de CaYman-Brac, mer des CaraXbes. * Comptes 

Rendus,' vol. c, pp. 755-758. 1885. 
Forster, Prof. Die durch den Ausbruch des Yulkans 

Krakataua verursachten atmospharischen Wellen. 

' Klein's Wochenschrift,' February 13, 1884. 
Foumet, J. Note sur un effet de Coloration des 

Nuages observ6 le 9 Mai, 1852, a Oullins. ' Annuaire 

de la Soc. Nationale d'Agriculture de Lyon.* 1853. 
[Freeden, W. von.] Der vulkanische Ausbruch anf Kra- 

katoa bei Java am 27 August, v. J. und die Dammer- 

ungserscheinungen der letzten Monate. * Hansa,' 

January 27th, 1884. 
Oasparin, P. de. Sur les lueurs cr^piisculaires observ^es 

dans les mois de Nov. et de Dec, 1883. * Comptes Ren- 
dus,' vol. xcvii., pp. 1400-1402 (1883); xcviii., pp. 280, 281 

(1884). 
Oelpke, Dr. 8. *Bat. Handelsblad,' September 8, 1883. 

Reprinted in * Times of Ceylon,' October 1, 1883. 
Hall, MaxweU. The Java Earthquake Wave. * Monthly 

Weather Report for Jamaica,' November, 1883; January, 

1884. 
Hann, J, Die aussergewohnlichen Dammenmgs-Erschein- 

ungen von Ende November und Anfang December, 

1883. *Zeitschrift fUr Met.,' vol xix. (1884), pp. 

20-30, 72-79. 
Haugrhton, Bev. S. Remarks on the unusual sunrises and 
. sunsets which characterised the close of the year 1883. 

* Proc. Royal Dublin Soc.,' vol. iv., pp. 203-205. 8vo. 

Dublin. 1884. ' 
Hasen, H. A. The Sun-glows. *Am. Joum. Science,' 

vol. xxvii., pp. 201-212, 1884. 
Hellmann, Dr. O. Beobachtungen iiber die Damraerung. 

'Zeite. fur Met.,' vol. xix., pp. 57-64, 162-175. 1884. 
Hemmer, J. J. Ephemerides Soc. Met. Palat; Obser. 

1783. 



Hopkixui, O. The Remarkable Sunsets. 'Nature,' voL 

xxiz. (1884), pp. 222, 223. 
Howard, Luke. ' Climate of London,' 3 vols. 1833. 
Jdy, J. Notes on the Microscopical Character of the 

Volcanic Ash from Krakatoa. * Proc. Royal Dublin 

Soc.,' vol. iv., pp. 291-299. 1884. 
Judd, Prol J, W., F.&.S. Krakatoa. *Proc. Royal 

Inst.,' May 2, 1884. 
Karsten, Q., und Floffel. Feste RUckstande im Regen- 

waaser. * Schriften d. Naturwis, Vereins f iir Schleswig- 

Holstein,' vol. v., pp. 137-141, 1884. 
Kennedy, H. Q. Report from H.M. Consul at Batavia, 

enclosing extract relating to the volcanic outbursts in 

the Sunda Strait, from the log-book of the steamship 

O, O, Loudon. *Proa Royal Soc.,' voL xxxvi., pp. 

199-205. 1884. 
KieasUnr, Prof. J. Zur Erklarung des braunrothen 

Ringes um die Sonne. * Das Wetter,' voL i., p. 48. 
Beobachtungen des rothen Sonnenringes. * Daa 

Wetter,' vol. L, p. 172. 

Ueber die Geographische Verbreitung des 



Bishop'schen Sonnenringes. * Das Wetter,' voL iL, p. 81. 
Ueber die Entstehung des zweiten Purpurlichtes 



und die Abhangigkeit der Dammerungsfarben von 

Druck, Temperatur und Feuchtigkeit der Luft * Das 

Wetter,' vol. ii, pp. 161-172. 
Nebelgliih-Apparat. 'Abhand. d. Naturwis. 

Vereins von Hamburg,' vol. viii. 1884. 
Ueber den Einfluss kUnstlich erzeugter Ncbel 



aufdirektesSonnenlicht *Met.Zeits.,' pp. 117-126. 1884 
Ueber Diflfractionsfarben in kilnstlich erzeugtem 



Nebel und deren Zusammenhang mit den Dammer- 
ungserscheinungen, 'Tageblatt d. 57. Yersamm. 
deutacher Naturforscher u. Aerzte,' September 23, 1884. 
Die Dammerungserscheinungen im Jahre 1883, 



und ihre physikalische Erklarung.' 8vo., Hamburg. 

1885. 
Ueber die Bewegung des Krakatau-Rauches im 

September, 1883. 'Sitzungsb. der K. Preussiacben 

Akademie der Wissenschaften zu Berlin,' vol. xxx. 

(1886), pp. 529-533. 
On the Cause of the Remarkable Optical Atmos- 
pheric Effects in 1883 and 1884. Warner Prize Essay, 

* History and Work of the Warner Observatory,' vol. i 

1887. 
Klooa, Dr. J. H. Die Yulcanische Eruption. * Badische 

Landeszeitung,' February 16, 1884. 
lAffrangre, E. L'Aurore et le Crepuscule. 'Ciel et Terre,' 

5th year (1885), pp. 129-140. 
Le Oonte, J. Atmospheric Waves from Kratatoa. 

'Science,' vol. iii., pp. 701, 702. 1884. 
Iieaseps, F. de. Propagation marine de la commotion du 

tremblement de terre de Java. * Comptes Rendus,' 

vol. xcvii, pp. 1172-1174. 1883. 



[ i^ J 



Uala, XL Sur la hauteur de Tatmosphdre d6duite d'obeer- 

vatioDs de polarisation, &c. *Comptes Rendus,' vol. 

xlviiL (1869), pp. 109-112. 
Lias, B. de St. Pol. Sur cette mdme Eruption volcanique 

du d^troit de la Sonde. * Bull. Soc. G6og./ Stance 

Nov. 9, pp. 526-529. 1883. 
Iiockyer, J. N., F.B.S. The recent Sunrises and Sunsets. 

'Times,' Dec. 8, 1883. 
Xaine, H. C. The Red Light. Warner Prize Essay, 

'Hist, and Work of the Warner Obser.,' vol. i. 1887. 
ICaaley, W. B. A Green Sun in India. * Nature,' vol. 

xxviii., pp. 676, 577 ; 611. 1883. 
ICaskelyne, N. Story-. The remarkable Sunsets. ' Nature/ 

vol. xjax.y pp. 286, 286. 1884. 
Xeldlnffer, Prot Ueber die Dammerungserscheinungen. 

'Badische Landeszeitung,' Feb. 2, 1884. 
Xeldmin, Br. Charles, F.B.S. A Tabular Statement of 

the Dates at which, and the Localities where, Pumice 

or Volcanic Dust was seen in the Indian Ocean in 

1883-4. * British Association Report,' 1885, p. 773. 
Proc. Mauritius Meteor. Soc., Meetings of Oct. 

27, 1883, and May 22, 1884. 
XetBK«r, E. Gleanings from the Reports concerning the 

Eruption of Krakatoa. * Nature,' vol. xxix., pp. 240- 

244. 1884. 
Xnrray, John, and Benard, X. A. Volcanic Ashes and 

Cosmic Dust * Nature,' voL xxix., pp. 585-690. 
Ketimayer, Dr. O. Bericht liber die vulkanischen Aus- 

bniche des Jahres 1883, in ihrer Wirkung auf die 

Atmosphare. * Meteor. Zeits.,' Jan. to Aug., 1884. 
Ueber die jiingsten vulkanischen Ausbruche in 

der Sundastrasse in ihrer Einwirkung auf die Atmos- 
phare. * Verhandl. Gesells. f. Erdkunde,' Berlin, vol. xi., 

pp. 87-94. 
Oebbeke, K. Ueber die Kratatoa-Asche. ' N. Jahrb. f. 

Min.' Bd. il, pp. 32, 33. 1884. 
Paul, H. X. Krakatoa. 'Science,' vol. iv., pp. 135, 136. 

1884. 
Electric Potentials and Gaseous Pressure. * Am. 

Meteor. Journal,' Aug., 1884. 
Barometric Waves of very Short Period. *Amer. 



Met Jour.,' voL L, No. 1. 
Pelagaud. Nouvelles Observations d'illuminations cr6- 

pusculaires k I'Ue Bourbon. 'Comptes Rendus,' vol. 

xcviiL, pp. 1301-2. 1884. 
Perrotlii et ThoUon. Note sur les cr6puscules extra- 

ordiualres de 1883-4. ' Ann. de Chimie,' 6e Ser., t. 1, 

pp. 433-449. 1884. 
Perry, Bov. 8. J., 8. J., P.B.S. The Upper Glow, &c. 

Results of Met and Mag. Obs. at Stonyhurst Ck>llege, 

1883-86. 
PfSail, Ii« Or., von. Spiegelungen mit besonderer Beriick- 

sichtigung der doppelten Morgen- und Abendr3theu 

erklart Zweite Auflage, Berlin. 1884. 



Prince, C. L. The Summary of a Meteor. Journal kept 
at Crowborough, Sussex, 1883. 

Baffona, Prof. Domlnioo. Sui Crepuscoli Rossi dell' Au- 
tunno, 1883, e dell' Invemo, 1883-84. 'Mem. d. R. 
Accad. di Sci. Lett, ed Arti di Modena,' vol. iiL, p. 66. 

Banyurd, A. C. The Extraordinary Sunsets. * Know- 
ledge,' pp. 341, 342, 1883 ; pp. 155, 156 ; 177, 178 ; 261- 
263. 1884. 

Benard, A. Les cendres volcaniques de I'^ruption du Kra- 
katoa tomb^es a Batavia, le 27 Ao&t, 1883. 'Bull 
Acad. Roy. Belgique,' 3rd ser., vol. vi., pp. 495-506. 
1883. 

Benou, E. Sur les oscillations barom6triques produites 
par r^ruption du Krakatoa. * Comptes Rendus,* vol. 
xcviii., pp. 160, 161 ; 245, 246. 1884 

Biccb, Prot A. Riassunto delle osservazioni dei crepus- 
coli rossi. Nota i., ii., iii., iv. ' Reale Accad. d. Lincei, 
1884-6. 

Sur la singuli^re couronne qui entoure le Soleil. 

* Comptes Rendus,' vol. xcviii., pp. 1299, 1300. 1884. 

Osservazioni e studii dei Crepuscoli rosei 1883- 



1886. ' Estratto dagli Annali della Meteorologia Ital- 
iana, parte i., 1885. Roma, 1887.' 

Biffffenbaoh, Dr. Albert. Beobachtungen Uber die Dam- 
merung insbesondere Uber das Purpurlicht und seine 
Beziehungen zum Bishop'schen Sonnenring.' 12mo. 
Basel, 1886. 

Wittenmgsiibersicht des Jahren 1883-4. * Ver- 

handlungen der Naturf orschenden Gesellschaft in Basel. 
8vo., 1885. 

BinfiTwood, A. Red Sunsets. * Nature,' vol. xxx., pp. 
301-304. 1884 

Bbttger, B. ' Die Dammerungserscheinungen. ' Mainziger 
Journal,' March 11, 1884. 

Bussell, Hon. F. A. BoUo. The Sunsets and Sunrises of 
November, 1883, to January, 1884 * Q. J. Royal Met 
Soc.,' vol. X., pp. 139-152. 1884 

Bykatohew. Note sur les ondes atmosph6riques pro- 
duites par I'eruption de Krakatoa. ' Bull. Acad. Imp. 
Sci, St Petersburg/ vol. xxix., cols. 389-404 1884 

Sandlok, Van. irruption du Krakatoa. ' Cosmos,' vol. 
viii., p. 677. 1884. 

Soott, B. H Note on a series of barometrical disturb- 
ances which passed over Europe between the 27th and 
the 31st of August, 1883. * Proc. Royal Soc.,' vol. xxxvi., 
pp. 139-143. 1884 (Abstract printed in * Zeits. f. 
Met,' 1884, pp. 97-102.) 

Shaler, N. 8. The Red Sunsets. ' Atlantic Monthly ' for 
April, 1884. 

Smyth, C. Plaszi. The remarkable Sunsets. 'Nature,' 
voL xxix., pp. 149, 150. 1883. 

Spitta, E. J. Observations of . . . the Moon during the 
Eclipse of October 4, 1884 Mon. Notices, R.A.S.,' 
January 7, 1886. 



6 2 



[ X ] 



Stanley, W^ F. On certain EffecU which may have beoa 

produced in the Atmosphere by floating Partidea of 

Volcanic Matters from the eruptions of Krakatoa and 

Mt. St Augustin. ' Q. J. KoyaL Met. Soc./ vol. x., pp. 

187-194. 1884. 
Stone, E. J. Total Eclipse of the Moon, October 4, 1884^ 

* Mon. Notices, RA.S.' November, 1884. 
Straohey, I«t.-Oen. B. Notes on R. H. Scott's Paper on 

Barometrical Disturbances of August, 1883. *Proc. 

Roya ISoc,' vol. xxxvi., pp. 143-151. 1884. 
Taoohini, P. Sur les oscillations barom6triques produites 

par r6ruption du Krakatoa. 'Gomptes Bendus,' voL 

xcviii, pp. 616, 617. 1884. 
Thirion, P. J. Les illuminations cr6pusculaires. ' Bevue 

des questions scieutifiques,' Bruxelles, April, 1884. 
Thcllon, I<. Sur certains changements observe k Nice 

dans Taspect du cieL 'Comptes Rendus,' voL xcviii., 

pp. 760, 761. 
Sur les couronnes solaires. * Comptes Bendus,' 

vol. xcix., p. 446. 1885. 
Verbeek, B. D. X. ' Kort Yerslag over de Uitbarsting 

van Krakatau.' 1884. Translated in * Nature,' voL 

XXX., pp. 10-15. 1884. 

* Krakatau.' 1885-6. 

Vereker, Capt. Hon. F. O. P. (H.M.S. Magpie.) Extracts 

from a Report on the Volcanic Eruption in Sunda Strait. 

Proc. Royal Soc.,' vol xxxvL, pp. 198, 199. 1884. 



Wa]k«r,r J. T., Iit.^aettanU. The Earthquake o£ Slst 

December, 1881. Extract from Report of the Survey 

of India for the year 1881-2. 
Earthquake Disturbances of the Tides on the 

Coasts of India. * Nature,' voL xxix., pp, 358-360. 
Watson, Oapt. (of the Charles Bed), The Java Disaster. 

•Nature,' voL xxix. (1883), p. 140. 
Weston, B. P. Atmospheric Waves from Krakatoa. 

* Science,' voL iiL, p. 531. 1884. 
Whymper, B. The remarkable Sunsets. 'Nature,' voL 

xxix., pp. 199, 200. 1883. 
Winlook, W. O. The long continued bad seeing. 'Sdenoe,' 

voL iv., pp. 94, 95. 1884. 
Wolf; O. Sur les ondulations atmosph^riques attributes 

4 r^ruption du Exakatoa. 'Comptes RenduSy' voL 

xcviii, pp. 177-179. 1884. 
Woods, Bev. J. B. Teaiaon-. The Earthquake in the Strait 

of Sunda. 'Sydney Morning Herald,' January 16, 17, 

18, 1884 
Wraffffe, Caement Ii. Remarks on the "Red Glow." 

'Transactions of the Royal Society of South Australia.' 

1884 
The Sun-gbw. ' English Mechanic,' September 

12, 1884 
Zenker, Br. von. Der braune Ring um die Sonne bei 

totalen Sonnenfiostemissen. 'Met Zeits.,' ppi 400-406. 

1885. 



CONTENTS. 



PAas 
Explanation op Coloubbd Fbontispiece. 
Prefatory and Historical ... ... ... ... ... ... ... ... Hi. 

List op some Books and Papers published rbspbcting the Phenomena reported upon ... vii. 



PART I. 

ON THE VOLCANIC PHENOMENA OF THE ERUPTION, AND ON THE NATURE 
AND DISTRIBUTION OP THE EJECTED MATERIALS. By Professor J. W. 
JuDD, 1*.J3.S., President of the Geological Society ... .. ... ... ... 1-56 

Introduction ... ... ... ... ... ... ... ... ... 1 

Sketch of the History of the Volcano op Krakatoa ... ... ... ... ... 3 

Eruption of 1680 (10) ; Eruption of May, 1883 (11) ; Eruption of August 26tli, 27tli, 
1883 (14) ; Smoke column, estimated as 17 miles high (19) ; Rain of pumice' (19) ; Sul- 
phurous smell (19) ; Phosphorescent mud rain (21) ; Two- thirds of the island disap- 
peared (22); Vessels stranded by seismic waves, and 36,380 persons washed away or 
otherwise killed (26) ; Darkness extended 150 miles from volcano (27) ; Great fall of dust 
and mud (27) ; Eruption compared with those of other volcanos in 1772, 1783, and 
1815 (29). 

The Materuls ejected from Krakatoa ... ... ... ... ... 29 

Geological structure of EIrakatoa (29). 

TheLavas ... ... ... ... ... ... ... . .. 30 

Analysis of pumice (32) ; Other analyses (33). 

ThePwnice,,, ... - ... •• ... ... .. ... ... ... 36 

Mr. Waller's analysis (38). 

The Volcanic Dust ... ... ... ... ... ... ... ... ... 38 

Analyses of dust which fell at Krakatoa, and 100 and 900 miles from it (40). 

General Oonclwions ... ... ... ... ... ... ... 42. 

Mr. R. H. Scott, F.E.S., on the Pumice . . ... ... ... ... ... 47 

A Tabular Statement of the Dates on which, and the Localities where, Pumice or Volcanjo 

Dust was seen in the Indian Ocean in 1883-4. By Charles Meldrum, LL.D., F.B,8, 48 
Explanation of Plates II., IIL, and IV. ... ... .. ... ... follow 56 



M 



[ ^ii ] 



PART II. 

PAGE 

ON THE AIR WAVES AND SOUNDS CAUSED BY THE ERUPTION OF 
KRAKATOA IN AUGUST, 1883. Prepared in the Meteorological Office, and pre- 
sented by Lieutenant- General R. Strachky, F.li.S., Chairman of the MeteoVological 
Council ... ... ... ... ... ... ... ... ... 57-88 

Section I. — Air Wavks ... ... ... ... ... ... ... ... 57 

Station.s from which barometrical or other observations have been received, with a 
description of the recording instruments and dates (58) ; Geogi'aphical position of 
Krakatoa, and of the principal stations from which data have been supplied (62) ; 
Times of passage of air-waves over each station (65) ; Probable moment of great 
explosion (69) ; Batavia gasometer indicator (69) ; Velocities of air waves (70). 

Skction II. — Sounds ... ... ... ... ... ... ... ... 79 

Detonations heard over nearly one-thirteenth of the surface of the globe (79) ; 
Sounds heard at Rodriguez, more than 2,500 miles from Krakatoa (79) ; List of places 
at which sounds were heard (80). 



PART III. 

ON THE SEISMIC SEA WAVES CAUSED BY THE ERUPTION OF KRAKATOA, 
AUGUST 26th and 27th, 1888. Bj Captain W. J. L. Wharton, E.N,, KB.S., in 
Completion of the Unfinished Notes of Captain Sir F. J. Evans, B,N,^ K.CB.y FM.S. 89-151 

Account of the phenomena relating to sea disturbance in the immediate vicinity of 
Krakatoa (90) ; Chinese" camp at Merak swept away, village of Sirik submerged, Anjer 
swept away, Telok Betong submerged, Tyringen destroyed (90) ; 1^ cubic miles of 
Krakatoa blown away, the Peak of Krakatoa shorn in two (93 ) ; Former surveys 
untrustworthy (91) ; Verlaten Island increased threefold. Two new islands of mud 
and pumice (92) ; A wave 135 feet high. A man-of-war carried 18 miles inland up the 
valley and left 30 feet above the sea-level. The great wave, how formed. The island 
shrouded in smoke and fire (93) ; Batavian tide-gauge (94) ; The record of the seismic 
sea waves (95) ; The cause of the great waves (97) ; The missing mass of Krakatoa 
estimated at 200,000,000 ^cubic feet (98) ; The experimental explosions at Spithead (99) ; 
A wall of water 150 feet high (99) ; Wave movements in connection with the Krakatoa 
eruption (100) ; Table showing height of wave (106) ; Tidal diagrams (107) ; The Sur- 
veyor General's Report on the tidal waves at Ceylon (116) ; Sea ebbed and flowed 
sixteen times in three hours (319) ; Bones' Island partly washed away (122) ; The time 
between the crests of the long waves (126) ; Main conclusions (148) ; Speed of free 
waves, by Sir George Airy (149) ; List of tidal diagrams (150); Tabular result of 
discussion of seismic sea- waves from Krakatoa (150). 



[ Jf'" ] 



PART IV. 

PAOB 

ON THE UNUSUAL OPTICAL PHENOMENA OF THE ATMOSPHERE, 188^-6, 
mCLUDINO TWILIGHT EFFECTS, CORONAL APPEARANCES, SKY HAZE, 
COLOURED SUNS, MOONS, Ac. By the Hon. F. A. Rollo Russell and Mr. E. 
Douglas Archibald ... ... ... ... ... ... ... ... 161-463 

Section I. (a). — Descriptions op the Unusual Twilight Glows in various parts of the World. 152 

Selections from correspondence (153) ; DijSerences between tke nnnsnal twilight 
glows and the ordinary sanset effects (172). 

Section I. (b). — Proximate Physical Cause of the Unusual Twilight Glows ... ... 178 

The eruption of Cotopaxi (183) ; Fragments of babbles of glass so small that from 
4000 to 25,000 were required to make a grain in weight (183) ; 1,000,000,000 
to 10,000,000,000 cavities in a cubic inch (183) ; Arago on the prolonged twilights of 
1831 (191) ; Summary of evidence respecting the particles of dust (195) ; Professor 
Kiessling on the after-glows (196) ; Professor Bicco on the after-glows (198). 

Section I. (c). — The Blue, Green, and other Coloured Appearances of the Sun and Moon 199 

list of places at which the sun was observed to be blue, green, or silvery (204) ; 
Professor Michie Smith on the green sun in the tropics (210) ; Professor Piazsi Smith 
and others on coloured suns as seen through various media (213) ; Summary (217). 

Section I. (d). — ^The Skt-haze and some or its Effects ... ... ... ... 219 

Peculiar features of the haze (223) ; Colour of the moon during the total eclipse on 
October 4th, 1884 (225) ; Secular duration of the haze (227) ; Summary (229). 

Section I. (e). — ^The large Corona round the Sun and Moon in 1883-4-5, generally 

KNOWN AS "Bishop's Ring" ... ... ... ... ... ... ... 232 

Table giving date, observer's name, locality, and remarks (234) ; Table giving the 
angular diameter of corona round the sun (235) ; Table giving the angular diameter of - 
corona round the moon (236) ; Diurnal and secular duration of the large corona (238) ; 
Table giving the period of its continuance, observer, or authority, and locality (239) ; 
Dates on which the corona has been seen since the summer of 1884 (240) ; Mean 
intensity of the Corona (241) ; Peculiar features of the corona (242) ; Disappearance 
of Bishop's Ring id Colorado (246) ; Connection between Bishop's Ring and the unusual 
twilights (247) ; Professor Ricc5's opposition to the views of Drs. Riggenbach and 
Eliessling (249) ; General opinions regarding the corona (251) ; Summary (255). 

Appendices to Corona Section 1. (e). — Discussion and account of experiments in connection 
with diffraction coronas and Bishop's Ring, by Professor Kiessling (258) ; Polari*- 
BGopic observations, by M. Comu (261). 

Section II. — General List of Dates of First Appearance of all the Optical Phenomena 263 

Seotton III. (a). — General Geographical Distribution of all the Optical Phenomena in 

Space and Time ; including also VELOCiTr of Translation of Smokb Stream ... 312 - 

Geographical distribution of peculiar sky phenomena (312) ; Summary (323). 



[ xiv ] 

TJLQM 

Section III. (b). — Connection between the Propagation of the Sky-uaze with its accom- 
panying OpriCAL Phenomena, and the General Circulation of the Atmosphere ... 326 

Table of districts east of Krakatoa, with distances, and daration of darkness, ashes, 
&c, (327) ; Ditto west of Elrakatoa (328) ; Tables of mean velocity of ash stream in 
miles per hoar (330 and 333) ; Rev. S. £. Bishop on the equatorial Fmoke stream (333) ; 
Materials from Krakatoa shot obliquely to a distance of from 30 to 70 miles (334), and 
vertically to a height of 31 miles (334). 

Section III. (c). — Spread op the Phenomena roond the World, with Maps Illustrative 

thereof ... ... ... ... ... ... ... ... ... 334 

The spread of the phenomena round the world (334) ; Statistical details connected 
therewith (335) ; Speed of progp:%ssion of blue sun phenomena ; of the haze, and of the 
red fore-glows and after-glows (337). 

Section IV. — Diurnal a^d Secular Variation in the Duration and Brilltancv of the 

Twilight Glows, and the Height above the Earth of the Stratum which caused them 340 

Prof. Story-Maskelyne on the twilight glows (340) ; List of observers of two glows 
at sunrise or sunset (344) ; Duration of the twilight glows (345) ; Height of stratum 
which produced the glow effects, estimated by different observers (348) ; FormulsB and 
calculations respecting the altitude (350) ; Summary (380). 

Section V. — Previous Analogous Glow Phenomena, and corresponding Eruptions ... 384 

List of principal ascertained volcanic eruptions from 1500 to 1886 (384) ; List of 
remarkable atmospheric phenomena, such as blue suns, dry fogs, and red twilights (384) ; 
Notes respecting detailed accounts of twilight phenomena m some particulai's similar 
to those of 1883 (404). 

Section VI. — Individual Opinions expressed and Hypotheses suggested to account for the 

ABNORMAL OPTICAL PHENOMENA... ... ... ... ... ... ... 4G6 

List of authorities quoted in this section (425). 

Section VII. — General Analysis of the Connection between the unusual Meteorological 

Phenomena of 1883-6, and the Eruptions of Krakatoa in May and August, 1883 ... 426 

Discussion of various objections (426) ; Diagram of atmospheric circulation (432) ; 
Summary of the evidence in favour of the connection of all the optical phenomena with 
the eruptions of Krakatoa (45G). 



PART V. 

REPORT ON THE MAGNETICAL AND ELECTRICAL PHENOMENA ACCOM- 
PANYING THE KRAKATOA EXPLOSION. Prepared at the request of the 
Kew Committee, bj G. M. Whipple, B.Sc.y Superintendent of the Kew Observatory, 



Richmond, Surrey 
Index of Places mentioned in the Report 
Index of Persons mentioned in the Report 
Index of Ships mentioned in the Report 



465 
476 
486 
491 



[ '^v ] 



ILLUSTRATIONS. 



Pi.OB 

J Pbontispiece. — Golonred Ckromo-Lithographs of Sunset-Glows as seen at Chelsea, NoTember 

26th, 1883. Precede Title. 

• Plate L — View of EZrakatoa during the May Eruption ... ... ... ... faces 1 

Fig. 1.— Sketch-Map of the Sunda Strait, showing the Lines of Volcanic Fissure which appear 

to traverse the District ... ... ... ... ... ... ... 4 

Fig. 2. — Sketch of the Island of Sebesi, as seen from the north-east... ... ... ... 5 

Fig. 3. — Map of the Islands of the Krakatoa Group (from the Admiralty Chart) ... ... 6 

Fig. 4. — Outline Section, viewed from S.W., showing the position of the Volcanic Cones upon the 

Island of Krakatoa previous to the Eruption ... ... ... ... ... 6 

Fig. 5. — Probable Outlines of the Volcano of Krakatoa, at the period of its maximum dimensions 7 

Fig. 6. — Probable Outlines of the great Crater Ring ("basal wreck") of Krakatoa Volcano, 

after the paroxysmal outbursts ... ... ... ... ... ... . 8 

Fig. 7. — Probable Outlines of the Krakatoa Volcano after the great Crater had been filled up by 

the growth of numerous small Cones within it ... ... ... ... ... 8 

Fig. 8. — Form of Krakatoa in Historical Times after the Formation of the great Lateral Cone of 

Rakata, and the growth of other Cones within the great Crater ... ... ... 9 

Fig. 9. — Chart of Sunda Strait to illustrate the Positions of the Towns and the Tracks of the 
Vessels, where the most important observations, bearing on the great final outburst 
at Kraktaoa, were made 

Fig. 10. — Outline of the Crater of Krakatoa as it is at the present time, and showing, by dotted 
lines, the portions blown away in the paroxysmal outburst of August, 1883... 

Fig. 11. — ^Map of Krakatoa and the surrounding Islands, from the Chart prepared immediately 
after the Eruption ... 



PIiATB 

' II. — Two views of Krakatoa after August ... 

'III. — Sections of Rocks ... 

^ rV. — Sections of Pumice 
• V. — Chart showing Sites of Pumice in the Indian Ocean, August-December, 1883 
VI. — Chart showing Sites of Pumice in the Indian Ocean, January-November, 1884 
^VII. — Enlarged copies of selected Barograms 
• VIII. — Barometer Curves from forty stations ... 

^ IX. — Record of Batavia Gasometer 
^ X. — Passage of Air- Waves I. and II. 

^ XI. — Passage of Air- Waves III. and IV. ... 



follow 



17 
23 
24 

56 
56 
56 
56 
56 
88 
88 
88 
88 



[ xvi ] 



PLATB 

> XII. — Passage of Air- Waves V. and VI. 
XI II.— Passage of Air- Wave VII. 

XIY. and XY. — Diagrams Ulastrating Variations in velocity of air- wave 
XVI. — ^Area over which the sounds were heard 
Fig. 12.— Map of Ceylon 

PLATR 

XVII. to XXXI. — Beprodnction of Tidal Diagrams (for list see p. 150) 
XXXII. — Snnda Strait 66/bre the Eruption... 
XXXIII.— Sunda Strait a/fer the Eruption ... 
XXXIV.— Java Sea 
XXXV. — Mercator's Chart of the World, showing Path of Seismic Sea- Waves .. 
Fig, 13. — Diagram of Sunset Colours ... 
Fig. 14. — Diagram of Twilight Glows ... 

FLATS 

XXXVI. — Distribution of Optical Phenomena over the Globe ... 
XXXVII. — Distribution of Optical Phenomena at various dates 
XXXVIII. — Measurement of the height of Sun-glow Stratum ... 
Fig. 15. — ^Diagram of Height of Glow Stratum ... 

FLATS 

XXXIX. — Curves illustirative of Altitude of Glow Stratum 
Fig. 16. — Diagram of Atmospheric Circulation ... 

PLATS 

XL. —Copies of traces produced by Magnetographs at the time of the Ejakatoa 

XDI. — Eral{ atoa Magnetic Disturbance. Declination 
XLII. — „ „ ,, Horizontal Force .. . 

XLIII. — „ „ „ Vertical Force ... 



PACK 

follow 88 

88 



... 


88 


... 


117 


follow 


150 


»> 


152 


»» 


152 


)) 


162 


»1 


152 


... 


160 




175 


face 


334 


i» 


334 


>» 


352 


... 


354 


face 


SM 


... 


432 


explosion 
follow 474 


91 


474 


?» 


474 


91 


474 



ffr'aJcatoou. Rep. Roy. Soc. Com . 



PiaUl 





♦ h 



1 M' J I 



*> I 



x:*isi: 




1 



v-^"''.^/- ^^iJ^^Lf*-^ 



iiiiiiiiii 



iitt 



^immi^m 



Parksr & Coward. lUh. 



West JSrvwrnau It Co ianf 



View of Ki-akatoa. d';j.rirj.^ the Eaur-lier Stage of Lhe .triiption. 
•ProTTu ou PhxftoqroLpJv uxke^n., otu Svun,4Lcu/ thue 21^ of May, 1883. 



PART I. 



ON THE VOLCANIC PHENOMENA OF THE ERUPTION, AND ON THE 
NATURE AND DISTRIBUTION OF THE EJECTED MATERIALS. 

By Professor J. W. Judd, F.RS., President of the Geological Society. 



Introductory. 

During the closing days of the month of August, 1883, the telegraph-cahle from 
Batavia carried to Singapore, and thence to every part of the civilised world, the 
news of a terrible subterranean convulsion — one which in its destructive results to 
life and property, and in the startling character of the world-wide effects to which it 
gave rise, is perhaps without a parallel in historic times. 

As IS usual in such cases, the first reports of this tremendous outburst of the 
volcanic forces appear to have been quite misleading and altogether unworthy of 
credence. Nor is this to be wondered at. The towns and villages along the shores 
of the Sunda Strait were, during the crisis of the eruption, enveloped in a terrible 
darkness, which lasted for many hours, and, while thus obscured, were overwhelmed 
by a succession of great sea- waves ; those who succeeded in saving their lives amid 
these appalling incidents were, it need scarcely be added, not in a position to make 
trustworthy observations upon the wonderful succession of phenomena occurring 
around them. 

For some time after the eruption, the Sunda Strait Was almost impassable ; light- 
houses had been swept away, all the old familiar landmarks on the shores were 
obscured by a vast deposit of volcanic dust ; the sea itself was encumbered with 
enormous masses of floating pumice, in many places of such thickness that no vessel 
could force its way through them ; and for months after the eruption one of the 

B 



2 PBOF. JUDD OX THE VOLCANIC PHENOMENA. 

principal channels was greatly obstructed by two new islands which had arisen in its 
midst. 

The first accounts brought to Europe stated that Thwart-way Island, situated at 
the ed|tern entrance of the Strait, had been split into five portions ; that the Cape 
of Ar^r had been sundered by a great fissure ; that a number of small islands 
had subsided ; and that no fewer than sixteen volcanoes had burst into eruption 
within the Strait. Subsequently, however, it was found that those who had first 
made their way into the Strait after the great convulsion, had been altogether misled 
by the hasty and imperfect glimpses which they had obtained of the desolated district, 
and that the real centre of the volcanic disturbance was at Krakatoa, the actual 
eruptions being confined to that island and the district immediately surrounding it. 

The first efibrts of the Dutch Indian Government were, of course, directed to taking 
measures for the safety and relief of the survivors of this terrible catastrophe, and 
for restoring the navigation of the great marine highway between Java and Sumatra. A 
man-of-war was despatched to the Strait to visit the ports, and penetrate as far as pos- 
sible into the great bays on both sides of the Strait ; while a surveying vessel was ordered 
to make first a preliminaiy and then a detailed examination of the changes which had 
taken place, and which had rendered the existing charts almost useless. But no sooner 
was this accomplished, than the Government determined to undertake a complete 
scientific investigation into the effects of the eruption, and of the phenomena which 
accompanied it, as far as these could be ascertained by the inquiries of a Commission 
visiting the whole of the district chiefly affected by it. The Dutch Indian Govern- 
ment were fortunate in having at their disposal the services of the eminent geologist, 
Mr. R. D. M. Verbeek, whose surveys of Java, Sumatra, and of the actual scene 
of the outbreak, are widely known to the scientific world. The Dutch Scientific 
Commission, for inquiry into the nature and results of the Krakatoa eruption, was 
appointed on October the 4th, 1883 ; a preliminary report of its proceedings appeared 
on February the 19th, 1884 ;* and subsequently, the complete report, illustrated by 
an atlas of plates, and containing a very valuable permanent record of the event, was 
published in both the Dutch and the French languages.t 

At the commencement of 1884, the French Minister of Public Instruction, on 
the motion of the *' Commission des Voyages et Missions," directed MM. K£n£ Br6on 
and W. C. Korthals to visit the scene of the eruption, and to make a report as to the 
result of their enquiries upon the spot. Only a preliminary report of this Comnais- 
sion, dated May the 30th, 1884, has yet been published,^ but an interesting accoimt 

♦ * Kort verslag over de uitbarsting van Krakatau,' door R. D. M. Verbbek. 

t * Krakatan, par R. D. M. Verbbek, Ing^nienr en clief des Mines, Chevalier du Lion N^erlandais. 
Public I)ar ordre de son Excellence le Gouvernenr- General des Indes N^rlandaises.' Batavia. The first 
part of the Datch edition appeared in 1884, and o£ the French in 1885. The second part appeared in 
Dutch in 1885, and in French in 1886. 

+ ' Comptes Rendus,' torn, xcix., p. 395. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 3 

of the proceedings of its members, from the pen of M. Bk^n, has appeared in a 
French periodical.* 

The Sunda Strait, where this great convulsion occurred, connecting, as it does, 
the China Seas with the Indian Ocean, is one of the most important commercial 
highways of the globe, and many hundreds of vessels pass through it every year. 
During the time that the eruption of Krakatoa was in progress, a niunber of ships 
passed within sight of the volcano, and even at the crisis of the eruption several 
vessels were actually within the Strait, while others were in its immediate proximity. 
The observations made by captains or passengers in these vessels, as well as in others 
at greater distances, and recorded in log-books, diaries, letters to journals, &c,, are of 
very great value and interest ; for, those on shipboard were not exposed to the dangers 
incurred by the witnesses on the land, seeing that the destructive sea-waves passed 
harmlessly, and in some cases unobserved, by them. Inasmuch, however, as many 
months had to elapse before these ships could reach the various ports of Europe and 
America to which they were bound, it was long before all the facts and observations 
could be collected and compared. The members of the Krakatoa Committee of the 
Royal Society are under great obligations to the numerous captains and owners of 
merchant vessels, who, in response to an appeal made by them through the ' Times ' and 
other newspapers, have furnished them with copies of logs and other documents, 
and with specimens of pumice and dust collected at a great niunber of different 
points. 

To those who, like Herr Metzger, of Stuttgart, and Dr, Kloos, of Carlsruhe, 
have collected from Dutch and other newspapers statements bearing upon the 
eruption, and to journals which have opened their columns to correspondence on the 
subject, the Committee is likewise indebted for many interesting details which might 
otherwise have been lost. Very great value attaches to the mass of useful materials 
collected in the pages of ' Nature ' during the months which followed the eruption. 
To Mr. H. O. Forbes, also, who was at Batavia after the commencement of the 
eruption, and who took much pains in collecting information bearing on the subject, t 
the Committee's thanks are largely due. 

The whole of the circumstances attending the great catastrophe of the Sunda 
Strait have been so carefully investigated, and so faithfully recorded by Mr. Verbeek, 
in his able and comprehensive work, * Krakatau,' that it will only be necessary in the 
present part of this report to give a general srunmary of the order of events, dwelling 
especially upon those questions a right understanding whereof is necessary for the 
interpretation of the remarkable phenomena displayed in distant countries, which 
in the following parts of the report are shown to have been more or less directly 
connected with the volcanic disturbance at Krakatoa. 

The scene of this terrible catastrophe lies in the very heart of the district which 

♦ ' La Nature,' April 4 and 25, and May 16, 1885. 

t ' Proceedings of the Royal Geographical Society,' vol. vi. (1884), p. 129. 

B 2 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



has long been recognised as being at the present epoch the greatest focus of volcanic 
activity upon the globe. The Island of Java, with an area about equal to that of 
England, contains no fewer than forty-nine great volcanic mountains, some of which 
rise to a height of 12,000 feet above the sea-level. Of these volcanoes, more than 
half have been seen in eruption during the short period of the European occupa- 
tion of the island, while some are in a state of almost constant activity. Hot 
springs, mud-volcanoes, and vapour- vents abound in Java, while earthquakes are by 
no means unfrequent. The chain of volcanoes which runs through the whole of Java 
is continued in Sumatra on the west, and in the islands of Bali, Lombok, Sumbawa, 
Flores, and Timor on the east. 

The marked linear arrangement in this immense chain of volcanic moimtains 
points to the existence of a great fissure in the earth's (;rust, along which the subter- 
ranean energy has been manifested. The Strait of Sunda, which separates Java from 
Sumatra, is a shallow one, having a depth of rarely more than 100 fathoms. Along 
the line of this Strait we have evidence of a transverse fissure crossing the main 
one nearly at right angles {See Fig. 1). Upon this transverse fissure a number of 



SUMATRA 











Fig. 1. — Sketch-map of the Sunda Strait, showing the lines of volcanic fissure which appear to traverse 

the district. 



'N 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 5 

volcanoes have been thrown up, namely — Pajung, in Java, with a height of 1,500 feet ; 
the cone of Princes Island, 1,450 feet ; Krakatoa, 2,623 feet ; Sebesi, 2,825 feet ; and 
Bajah Bassd, in Sumatra^ 4,398 feet. 

In spite of the significance of its position at the point of intersection of these 
two great lines of volcanic fissure, Krakatoa had, until the year 1883, attracted but 
little attention. Amid so many volcanoes of more striking appearance and more 
firequent activity, it, in fact, remained almost unnoticed. 

Krakatoa does not present the regularly conical outlines characteristic of 
volcanoes, a form which is so well exhibited by the neighbouring island of Sebesi (See 
Fig. 2) ; it is, indeed, only a fragment of a great crater-ring rising out of the Sunda 




Fig. 2,— Sketch of the Island of Sehesiy as seen from the north-east (after Verheek), 

Strait. The general relations of the islands of the Krakatoa group and the outlines 
which they exhibited prior to the great eruption are illustrated by the accompanying 
sketch-map and section (Figs. 3 and 4, page 6). 

By the great eruption of August, 1883, the volcano of which Krakatoa and the 
adjoining islands form parts was completely eviscerated. The admirable descriptions 
given by MM. Verbeek and Br£on of the splendid sections now exposed enable us 
not only to determine the nature of its materials, but to study all the details of the 
internal structure of the volcanic mass. Guided by the principles which have been 
established by the study of numerous volcanoes in different stages of their develop- 
ment, we are able from the data thus obtained to re-construct the whole history of 
this interesting example of volcanic architecture. 



I. — Sketch of the History op the Volcano of Krakatoa. 

No principle of vulcanology is better established than that of the alternation, 
in the history of most volcanoes, of periods during which constant ejections take place, 
whereby great mountain masses, having the beautiful conical forms characteristic 
of Chimborazo and Fusiyama, are slowly and gradually built up, and of violent 
paroxysms, by which in the course of a comparatively short period, the whole centre 
of the great volcanic mass is blown away, and scattered in the form of scorisB and 
dust ; only the lowest and peripheral part being left behind in the form of a crater- 
ring, or " basal wreck," as Darwin so aptly called the ruins of an eviscerated 
volcano. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



The great volcanic mountain, of which Krakatoa, Verlaten Island, Lang Island, 
and Polish Hat are portions of a basal wreck rising above the waters of the ocean, 



SEBESI CHANNEL 



VERLATEN 



* r 

•mite Rock 



KRAKATOA I.C 




LAKOJ. 



<*>^ 



GREAT CHANNEL 



I 7 I 



En^UsK Miles. 



Fig. 3. — Map of the islands of the Krakatoa Group before the eruption (from the Admiralty Chart) . The 
nearly circular line indic<ites approximately the submerged edge of the great crater, 

Rakafa 
««f» ft 




VerlaWl 



Stream 



9is:iian^ 



Fig. 4. — Outline'Section viewed from south-west showing the position of the volcanic cones upon the Island of 

Krakatoa previous to the eruption, 

must have origiually been one of considerable dimenBions. Its circumference at what 
is now the sea-level could not have been much less than twenty-five miles, and its 
height above the same datiun plane was perhaps not less than 10,000 to 12,000 feet ; 
so that, as might have been expected from its position at the intersection of two great 
earth-fissures, this volcanic cone must have rivalled in its dimensions the largest among 
the volcanoes of the East -Indian Archipelago. The general form of the volcano at 
this period of its history is illustrated in Fig. 5. 

That this great volcanic mountain was entirely built up by eruptions which have 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 7 

taken place in very recent times, geologically speaking, is shown by an interesting 
fact which has been ascertained by Mr. Verbeek, namely, that beneath the mass of 
materials of which the volcano is composed there occur deposits of post-tertiary age, 
and that these in turn rest on the widely distributed tertiary rocks which are so 




Fig. 5. — Probable outlines of the Volcano of KraTcatoa^ at the period of its maximum dimensions. 

well known in Java, Sumatra, and the adjoining islands. The original volcano, as far 
as can be judged by the fragments which remain of it, appears to have been almost 
entirely built up of lava-streams of the remarkably interesting rock known as 
enstatite-dacite,* consisting of the same minerals which characterise the andesitic 
lavas so abundant in Java and Sumatra ; it nevertheless differs from the bulk of these 
by the higher percentage of silica which it contains. During the outwellings of these 
massive lavas there is scarcely any trace of explosive action on any considerable scale 
having taken place, and few, if any, tuffs were produced. 

At some unknown period this volcano became the scene of an eruption, or series 
of eruptions, which, judging from the effects they have produced, must have been on 
even a far grander scale than that which four years ago attracted so much interest. 
By these outbursts the whole central mass of the volcano seems to have been blown 
away, and only an irregular crater-ring left behind. The gi-eat crater thus formed 
must have had a diameter of three or four miles, and its highest portions could have 
risen but a few hundreds of feet above the present level of the sea. (See Fig. 6, p. 8.) 

The next stage in the history of the volcano consisted in the gradual filling up 
of the crater by a series of comparatively quiet eruptions, taking place at the bottom 
of the crater-ring, and building up small volcanic cones within it. By this means the 
crater was, to a great extent, filled up, and portions of it raised above what is now the 
sea-level. [See Fig. 7, p. 8). Whether the tract now constituting the Strait of Sunda 
was then dry land imiting the present islands of Java and Sumatra we have no means 
of determining ; but I may point out that there are some grounds for believing that 

♦ This rock lias been called by many authors ** enstatite- " or " hypersfcliene-andesite ; " but although 
the minerals present in the rocks are the same as those found in the *' enstatite-andesites " it has a 
silica-percentage of over 70, and it, therefore, belongs to the class of acid lavas. It bears, in fact, the 
same relation to the andesites that the rhyolites do to the trachytes, and on this account the name 
" dacite " may be convenieutly applied to it. 



8 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



the formation of the depression occupied by the straits was subsequent to the 
evisceration of the volcano. 

In a great number of cases it has been shown that the piling up of materials 
upon a portion of the earth's crust to form volcanic mountains is accompanied or 



FiQ. 6. — Probable outlines of the great crater-ring (" basal wreck '*) of the Krakatoa VolcanOy after the 
ancient paroxysmal outbursts. The dotted line indicates the mass which was blown away. 

followed by a depression of the surface, so that the strata all round the volcano 
acquire a downward dip towards the centre of eruption.* The cause of this depres- 
sion of the volcanic mass appears to be iwofo\(i— first, the removal of the support 
afforded by the vast masses of material removed from below the vent during erup- 
tions ; and, secondly^ the weight of the gradually increasing mountain-mass which 




Fig. 7. — Trobable outlines of the Krakatoa Volcano after the great crater indicated by the dotted line had 
been filled up by the growth of numerous small cones within it. 

rests on the flexible crust. It seems not improbable that the depression between the 
islands of Java and Sumatra may have resulted from subsidences accompanying or 
following the ejections taking place at the great central volcanic focus of Krakatoa. 

Subsequently to the partial in-filling of the great crater, a lateral or parasitical 
eruption seems to have taken place on the southern edge of the great crater-ring, and 
this outburst is remarkable for a very striking change in the nature of the materials 
ejected. The materials forming the cones inside the crater-ring were composed of 
materials similar to that of the latter itself, namely, the lava known as enstatite- 
dacite, but the new parasitical cone was built up of basaltic lavas and scoriae. The 
ejections from this lateral vent must have been abundant and long-continued, for they 

♦ Darwin, * Volcanic Islands,' p. 9 ; Heaphy, * Qnart. Journ. Geol. Soc.,' vol. xvi. (1800), p. 244 ; Scrope, 
'Volcanoes,' 2ud ed. (1872), p. 225; and the author, * Quart. Journ. Geol. Soc.,' vol. xxx. (1874), p. 257. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 9 

resulted in the piling up of a cone which, standing on the edge of the old crater-ring, 
rose to the height of 2,623 feet above the sea. (Fig. 8.) 

N.W. y^-V S.E. 




Fig. 8. — Form of KraJeatoa in historical timesy after the formation of the great lateral cone of Bakata,^ and 

the growth of other cones within tJie great crater. 

It was this conspicuous basaltic cinder-cone that was called by the natives the 
peak of Bakata, which in the old Kawi or Javanese language signifies a crab. The 
name, under the Dutch form, Krakatau, the Portuguese KrakatSo, and the English 
Krakatoa, has been extended to the whole island on which this striking cinder-cone 
stood. It is convenient to employ the same name also for the entire volcano of which 
this island constitutes the largest part rising above the ocean. 

Amid the numerous, lofty, and strikingly conical volcanic mountains of this 
district, the insignificant masses of Krakatoa and its neighbouring islets naturally 
attracted but little attention. The early voyagers in these seas describe the four 
small islands of the group, like the others in the Strait, as being clothed with the most 
luxuriant vegetation, and as affording a wonderful relief to eyes long accustomed to 
the monotony of a waste of waters. None of the islands of the Krakatoa group 
appears to have had at any time permanent inhabitants. The natives living in the 
towns and villages along the shores of the Strait merely visited the islands from time 
to time, in order to collect the produce of the magnificent forests which covered them ; 
while the anchorages and places of shelter around their shores were resorted to by 
the native fishermen. Consequently, while hundreds of vessels every year passed 
within a short distance of these remarkable islands, the characters of their interior 
remained almost unknown ; indeed, such phenomena as the outbm'st of hot springs 
and the occurrence of earthquake-shocks might, and probably did, occiir without 
attracting attention, although the outbreak of any considerable volcanic eruption would 
have given rise to steam-clouds that could not fail to attract the attention of those 
on board passing vessels. 

Unfortunately, neither the Dutch nor the English charts give any very exact 
details concerning the forms and contours of the islands. The two great channels to 
the north and south of the Krakatoa-group were carefully sounded, but of the islands 
themselves we have only the outlines rudely laid down (and these differ very greatly 
in the several published charts), with sketches of their form as seen from ships, and 
indications of their heights above the sea-level. A sketch of the island of Krakatoa 
was made by P. J. Buijskes, the captain of a Dutch man-of-war, in 1849, and another 
drawing of the islands of the group by Mr. Verbeek in 1880. The English chart, with 
sketches of some of the islands as seen from the sea, was made in 1854, and the 
Dutch chart in 1874; but additions and corrections to both these charts were made 

c 



10 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

from time to time by the surveying officers of both navies Nothing, however, in 
the shape either of a complete topographical or of a geological survey of the islands 
was ever undertaken ; and the absence of the information which would have been 
aiforded by such surveys, is very seriously felt in all attempts to estimate the exact 
nature and amount of the changes wrought by the late eniption. 

From all the information available, it appears that Krakatoa consisted of the regular 
basaltic cone known as Rakata, rising from the southern end of the island to the 
height of 2,623 feet, and having a small depression, probably marking a crater, at its 
summit. The northern part of the island seems to have consisted of a number of 
more or less regularly conical masses, two of which only had received distinct names. 
Near the centre of the island was the cone called Danan, and this, or a neighbouring 
peak, had a height of 1,496 feet, and is said to have had a crater at its top ; at the 
northern end of Krakatoa was the smaller cone called Perboewatan, with a height of 
399 feet, having a crater breached on its western side, fi'om which a stream of very 
glassy enstatite-dacite lava descended to the sea-level. Verlaten and Lang Islands 
were isolated portions of the old crater-ring, and rose to only a moderate elevation 
above the sea-level, while Polish Hat formed part of the masses ejected within the 
crater. {See Figs, 3 and 4, p. 6,) 

The native traditions collected by M. BntoN point to the conclusion that eruptions 
had taken place at Krakatoa during the time that the district had been inhabited by 
the Malayan tribes. Authentic history in this case, however, commences only about 
three centuries ago. 

In May, 1680, an eruption appears to have broken out at Krakatoa, of which we 
have unfortunately only very meagre accounts in the wi^itings of Vogel and Hesse. 
Great earthquakes are said to have been felt in the neighbourhood, and vast quantities 
of pumice to have been ejected, which covered all the surrounding seas. The eruption 
seems to have continued with little intermission till the November of the following 
year, and to have destroyed the rich tropical forests that covered the island. Which 
of the volcanic cones composing Krakatoa was then in eruption is not certainly known, 
but it may be plausibly conjectured that it was Perboewatan, upon the slopes of which 
conspicuous and very fresh lava-streams of enstatite-dacite are recorded as being seen 
by seyeraj later authors. The eruption at this time seems to have been of the 
conitiinual moderate character by the repetition of which the small cones occupying the 
grea{ter part of Krakatoa, and filling up the vast submerged crater, had been formed 

From the effects of this outburst, however, Krakatoa soon recovered, and the 
evei>i; smms to have been so far forgotten that doubts have even been expressed as to 
the accura^jy of the narratives recording it. For these doubts there do not seem to 
be any very good reasons. The rich vegetation which clothed the island made the 
inhabitants of the neighbouring shores and the passers in ships forget the terrible 
forces which were slumbering beneath a scene of so much beauty. Some, however, 
who landed on the island and made their way into the almost impenetrable forests 



PROF. JUDD ON THE VOLCANIC PHENOMENA, 11 

declared that they had met with hot springs, and one such spring is indicated on the 
Admiralty chart of the island. 

Six or seven years ago it became evident that the volcanic forces, which for 
nearly two centuries had remained dormant beneath the Sunda Strait, were once more 
awakening into activity. Earthquakes were of frequent occurrence, and during one 
of these, on September the 1st, 1880, the lighthouse on Java's First Point was 
seriously injured. These earthquakes were felt as far away as North Australia. 

On the morning of Sunday, May the 20th, 1883, booming sounds like the firing 
of artillery were heard at Batavia and Buitenzorg, which towns are situated nearly 
100 English miles from Krakatoa, and for many hours a rattling of the doors and 
windows was maintained in these towns and in all the neighbouring villages ; on' 
board a mail-steamer passing through the Strait, it was noticed that the compass- 
needles were violently agitated. 

On the morning of May the 21st a sprinkling of ashes was noticed to fall at 
Telok Betong and Semanka, on one side of the Strait, and at Buitenzorg and the 
mountains around that place on the other. But it was not till the evening of the 
same day that a steam-column, issuing from Krakatoa, revealed to the inhabitants of 
the district the true locality of the disturbance which had been going on for two days. 
On the 22nd of May, at 8 p.m., the captain of a vessel passing close to Krakatoa was 
able to see that the dome-shaped mass of vapour issued from the lower parts of the 
island, and not from the top of the peak of Bakata ; a succession of fiery flashes, each 
followed by a loud explosion, accompanied the discharge of fragments of pumice and 
dust into the atmosphere, while vivid flashes of lightning were seen playing around 
the vapour-column. Much of the pumice and dust fell beyond the limits of the 
island, and on May the 23rd a ship encountered a large quantity of this pumice off" 
Flat Cape, in Sumatra, which was found to increase in amount until Krakatoa was 
passed. The pumice was then floating' out into the Indian Ocean. 

It is evident from these accounts that Krakatoa had re-entered on a phase of 
moderate (Strombolian) activity, similar to that which it had exhibited for some 
months during the years 1680 and 1681. That the outburst was one of considerable 
violence, however, especiaUy at its commencement, was shown by the fact that the 
commander of the German war- vessel, Elisabeth, estimated the height of the dust- 
column issuing from the volcano as 11 kilometres (36,000 feet, or 7 miles) ; and falls 
of dust were noticed at the distance of 300 miles. 

Mr. H. O. Forbes, then resident at Timor, 1,350 English miles distant, relates 
that on May the 24th a small quantity of greyish dust fell there ; but it is possible 
that this may have come from some other and much nearer volcano than Krakatoa. 

It seems that the eruption, which was so violent at its first outburst, soon 

became of a more moderate character — so much so, indeed, that the residents in 

Batavia and other portions of the surrounding district, who are accustomed to hearing 

of earthquakes and volcanoes in their vicinity, soon ceased to pay much attention 

c 2 



12 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

to the subject. Mr. Yerbeek has, however, collected from the lighthouse-keepers on 
the shores of the Strait, and from the captains of the mail-steamers and other passing 
vessels, many very interesting details of this preliminary outbreak. 

On May the 26th an excursion party was formed at Batavia, and proceeded 
in a steam-vessel to the scene of the eruption. They reached the volcano on the 
Sunday morning. May the 27th, after witnessing, during the night, several tolerably 
strong explosions, which were accompanied by earthquake-shocks. Krakatoa and the 
adjoining islands were seen to be covered with fine white dust like snow, while the 
trees on the northern parts of Krakatoa and Verlaten Islands had been, to a great 
extent, deprived of their leaves and bmnches by falling pumice— =-a fate which those 
on Lang Island and Polish Hat, as well as on the Peak of Rakata, had to a great 
extent escaped. 

It was then seen that it was the cone of Perboewatan which was in activity — 
explosions occurring at intervals of from 5 to 10 minutes, and each of these explosions 
being attended with the uncovering of the liquid lava in the vent, whereby the over- 
hanging steam-cloud was lighted up and glowed for a few seconds. The column of 
vapour was estimated as rising to a height of less than 10,000 feet, and the fragments 
of pumice as being shot to the height of about 600 feet. It appears from these 
accounts that the violence of the eruption had somewhat diminished since the first 
detonations, which were heard so far off and were accompanied by so lofty a vapour- 
cloud. From some of the accounts, however, it appears that certain of the 
explosions were of exceptional violence, and that pieoes of pumice were thrown to 
very great heights in the atmosphere ; for it is said that they were caught by the 
upper currents of the air and carried away in a direction opposite to that towards 
which the wind was blowing at the time. The noise made by the explosions and the 
hurtling of the ejected fragments in the air, is said to have been so great that when 
a rifle was discharged its sound might be compared to " the popping of a champagne-, 
cork amid the hubbub of a banquet." 

Ascending ankle-deep in loose pumice over the slopes of the low depressed cone 
of Perboewatan, which was found to have a height of something over 300 feet above 
the sea, the visitors to the island found at the top a large crater 8,000 feet in 
diameter, and sloping down to a flat bottom which had about one-half that diameter, 
and was covered with a black crust. The crater-floor, which was about 150 feet from 
the upper edge, showed in its centre a cavity about 150 feet in diameter, from which 
the great steam-column issued with a terrific sound. The western side of the crater 
was seen to be breached by the obsidian lava-stream descending to the sea. It is 
conjectured that this was formed in 1680-81. 

The material ejected was pumice with fragments of black glass ; it is desci-ibed 
by some as containing crystals of plagioclase felspar, pyroxene and magnetite. A 
specimen brought away by one of the visitors was, however, given to Mr. H. O, 
Forbes, and by him brought to England ; and this specimen, which was handed 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 13 

to me by that gentleman, proved to be of a somewhat peculiar character and quite 
different from most of the pumice ejected during the later stages of the eruption, as 
will be shown in the sequel. 

A photographer on board the steamer succeeded in obtaining a satisfactory view 
of the eruption at that time, and this photograph, which was coloured by an eye- 
witness of the eruption, is reproduced in Plate I. 

After the period of this visit, although there was no intermission in the eruption, 
there appeared to be a decline in the volcanic activity, as far as can be judged from 
the reports obtained from the lighthouses of the Strait, and from the captains of 
passing vessels. It was ascertained at Anjer on June the 19th, that the height of the 
vapour-column and the force of the explosions were again increasing ; and on the 24th 
of the same month it was distinctly noticed that a second column of vapour was ascend- 
ing from the centre of the island. At Katimbang, from which place the Island of 
Krakatoa can be seen, it was noticed that the appearance of Perboewatan had entirely 
changed ; the conspicuous summit had disappeared, having probably been blown away 
during the enlarging and deepening of the crater. 

During the month of July, the eruption from the two points in the island was 
observed and described, both by witnesses on the shores and by others on vessels 
making the passage of the Strait. Some detonations of exceptional violence, and 
several small earthquakes, were from time to time recorded alike from the Java and 
Sumatra shores ; but in a district where earthquakes and volcanic outbursts are so 
frequent, this eruption of Krakatoa during the summer months of 1883 seems to 
have been regarded as nothing more than a nine-days' wonder, and soon ceased to 
attract any particular attention. 

On August the 11th, however, the island was visited by Captain Ferzenaar, the 
chief of the topographical staff of Bantam. Sailing along the north-east side of the 
island in a native boat he was able to make a sketch of that part of the island, the 
heavy masses of vapour and dust driven by the wind preventing him from examining 
the other portions of the island By this time the forests of the whole of Krakatoa 
appear to have been completely destroyed, only a few trunks of trees being left 
standing above the thick covering of pumice and dust. This mantle of dust near the 
shores W£U9 found to be 20 inches in thickness. 

Three large vapour-columns were seen ascending and carrying up immense clouds 
of dust and pumice from as many craters, one of these being the original crater of 
Perboewatan, while the other two were in the centre of the island. Of the latter, one 
was probably the original crater of Danan, enlarged and deepened by the explosive 
action so as to diminish the height of the cone, while the other crater seems to have 
been opened at the northern foot of Danan. But besides these three principal 
craters no fewer than eleven other foci of eruption could be observed on the visible 
portions of the island, from which smaller steam-columns issued and ejections of 
dust took place. 



14 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

It is evident, therefore, that at this period the activity of the volcanic forces in 
the island had increased in a remarkable manner, and that from all portions of the 
lower -lying parts of the island situated to the north of the Peak of Rakata, that is 
from the area within the walls of the original crater, outbursts were going on. 
This account of the state of the volcano on August the 11th is very interesting 
indeed, oa being the last which we have before the great paroxysm which occurred 
towards the end of the same month. 

The vessels which passed close to Krakatoa between the 11th of August and the 
time of the great catastrophe reported a heavy rain of pumice and dust and constant 
loud explosions as taking place. On the 25th the dust had been carried to such a 
height as to begin to fall at Telok Betong, nearly fifty miles distant. 

The eruption which began on May the 20th, and culminated in the tremendous 
explosion of August the 27th, thus appears to have exhibited the following vicissi- 
tudes : — Bursting out with somewhat sudden violence, the eruption from Perboewatan 
seems to have had sufficient force to carry the volcanic dust to various points along the 
shores of Java and Sumat ra. After this sudden outburst, there was a rapid and marked 
decline in violence, and then a gradual increase till June the 24th, when a second 
crater had opened in the centre of the island. The eruptive force still increasing, a 
third crater made its appearance^ and innumerable smaller vents were originated all 
over the surface of the fiUed-up crater of the great volcano. From this time the 
activity seemed still constantly to increase, till its grand culmination on the 27th of 
August. 

The Eruption of August 2(jth and 27th, 1883. 

On the afternoon of the 26th of August, and through the succeeding night and 
day till the early morning of the 28th of August, it was evident that the long- 
continued moderate eruptions (Strombolian stage) which had for some days been 
growing in intensity, had passed into the paroxysmal (Vesuvian) staga In order to 
weigh the evidence which we have concerning the nature of this critical and most 
interesting period of the eruption of Krakatoa, it may be well to consider what were 
the facilities for observation possessed by the several individuals from whom the 
reports concerning the eruptions were obtained. 

Situated respectively at a distance of 94 and 100 English miles to the east of 
Krakatoa are the two important towns of Batavia and Buitenzorg. In both these 
places, numerous Europeans capable of making accurate observations were resident ; 
there were also self-recording instruments, the tracings of which have proved of the 
greatest value in these enquiries. At numerous small towns and villages along the 
Javan and Sumatran coasts of the Strait of Sunda, and in the five lighthouses, two of 
which were destroyed, European officials were located. Many of these fled during the 
terrible night of the 26th of August, and others were drowned by thei great sea- 
waves which submerged all the coast-towns on the morning of the 27th. Very 



PROP. JUDD ON THE VOLCANIC PHENOMENA. 15 

admirably has Mr. Yerbeek collected and discussed the reports made by the officials 
of the coast- towns and villages who survived that night of horrors. 

Perhaps, however, the most important evidence of what was actually going on at 
Krakatoa during the crisis of the eruption is that derived from witnesses on board 
ships which sailed between Java and Sumatra while the great outburst was in 
progress, or those that were at the time in the immediate vicinity of either the 
eastern or western entrance of the Sunda Strait. From many more distant points, 
however, valuable confirmatory or supplementary evidence has been obtained, for 
which we are indebted to the captains or passengers of vessels passing through the 
eastern seas during that period. 

Only three European ships appear to have been actually within the Sunda 
Strait during the height of the eruption on the night of the 26th of August and the 
early morning of the 27th, and to have escaped destruction, so that those on board 
could tell the tale of what they witnessed. 

The greatest opportunities for observation seem to have been those which were 
afforded to Captain Watson of the British ship Charles Bed, then on its voyage to 
Hong Kong. This vessel passed Princes Island at 9 a.m, on Sunday the 26th of 
August; at noon she was on the south-west side of Krakatoa ; and at 4.15 p.m. she 
reached a point nearly due south of the volcano, and about 10 miles distant from it. 
The darkness being too great to permit of safe navigation, sail was shortened, and 
through the whole night the vessel was kept beating about on the east of the volcano, 
and within a dozen miles from it. At 6 a.m, on the 27th, the Java shore was sighted, 
and the vessel was enabled to continue her voyage. 

The Batavian steamship Oouvemeur-GeneracU Loudon, Commandant T. H. 
liiNDEHAN, left Batavia on the morning of the 26th of August, and reached Anjer at 
2 p.m. the same day. Leaving that port at 2.45 p.m., she sailed for Telok Betong, 
taking a number of coolies and women as passengers, and passing about 80 miles 
north of Krakatoa, reached her destination at 7.30 p.m. Finding at midnight 
that it was impossible, on account of the storm which was raging, to communicate with 
the shore, the vessel steamed out into the bay and anchored. She thus escaped being 
stranded by the great sea-waves of the early morning, like the unfortunate Govern- 
ment steamer Berouw, which was at this time anchored close to the pier-head at 
Telok Betong. At 7 30 a.m. on the 27th, the steamer G. G. Loudon started to return 
to Anjer, but had to come to anchor at 10 o'clock on account of the rain of pumice, 
and the storm that was raging. During Tuesday, the 28th, she steamed round the 
west and south sides of Krakatoa, called at the part of the coast where Anjer formerly 
stood, and then proceeded to Batavia. 

The Dutch barque Marie, engaged in the salt- trade, was, during the whole time of 
the eruption, anchored off Telok Betong. On the morning of the 27th of August, thanks 
to the precaution of putting out a third anchor, she rode safely, and was able to avoid 
being stranded by the gigantic sea- waves, which swept on to the land the Government 



16 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

steamer Berouw, three schooners, and many smaller craft lying off the same port. 
The vessel appears to have been at times in imminent danger, but only four of the 
persons on board of her were drowned. 

During the whole of Sunday, the 26th of August, two vessels, the barque 
Norham Castle, Captain O. Sampson, and the ship Sir Robert Sale, Captain W. T. 
WooLDRiDGE, were at the eastern entrance of the Strait, and about 40 miles from 
Krakatoa. On the morning of Monday, the 27th, both these vessels entered 
the Strait, but owing to the darkness, neither made much progress till the morning 
of the 28th, when, falling in with each other, they made their way in company, 
but with much difl&culty, through the Strait. 

The Dutch hopper-barge, Tegal, which sailed from Batavia for Merak early on 
Monday, the 27 th of August, remained at anchor near the eastern entrance of the 
Strait during the great darkness, but on Tuesday, the 28th, entered the Strait 

On the morning of Sunday, the 26th of August, the ship Berhice, of Greenock, 
Captain William Logan, was at the western entrance of Sunda Strait, and about 
40 miles from Krakatoa. This vessel remained beating about the entrance till 
Wednesday, the 29th, when she was able to sail through the Strait. 

These are the vessels which, during the crisis of the great eruption, were in the 
most favourable positions for those on board of them to make observations concerning 
what was taking place at Krakatoa. The approximate positions of these vessels are 
shown in the accompanying chart (Fig. 9). Let us now turn our attention to some 
other vessels which were at greater distances from the scene of eruption, but, from 
the captains or passengers on board which, valuable information has been received. 

The Norwegian barque Borjild, Captain Amundsen, was at anchor near Great 
Kombuis Island, 75 miles east-by-north of Krakatoa, during the 26th and 27th of 
August. 

The British ship Medea, Captain Thomson, was, at 2 p.m. on the 26th, in the 
vicinity of the last-mentioned vessel, and sailing eastward came to anchor about 89 
miles from Krakatoa. 

The American barque William H. Besse, Captain Baker, on its way from 
Manilla to Boston, U.S.A., having called at Batavia, was in the same neighbourhood, 
and on Wednesday, 29th, and Thursday, 30th of August, was passing through the 
Strait. 

The British steamer Anerley, Captain Strachan, bound from Singapore to 
Mauritius, was, on the 26th of August, in Banca Strait, 250 English miles north of 
Krakatoa. During the 27th the steamer remained at anchor near North Watcher 
Island, 92 English miles north-east of the volcano. 

The Siamese barque Thoon Kramoom, Captain Andersen, bound from Bankok to 
Falmouth, lay, on the 27th and 28th of August, in the Strait of Banca, 230 English 
miles north of Krakatoa, and, sailing southwards, passed through the Strait of Sunda 
on the 31st of August. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



17 




18 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

Several vessels, among which was the barque Hope, were lying in Batavia Bay 
during the great paroxysmal outburst. 

The mail steamer Frinses Wilhelmina, which passed through the Strait on the 
23rd of August, coming from the west, remained at anchor at Batavia during the 
time of the great eruption. 

Among vessels which were at still greater distances from the volcano during the 
time of the great outburst, the following may be mentioned as those from which 
information and specimens of the falling pmnice and duet have been received : — 

The British ship Bay of Naples, Captain TroiiARSH, was, during the eruption, 
about 138 English miles south of Java's First Point, and the barque Luda was 
about 300 miles to the south-east of Krakatoa. 

From the seas to the west of the Strait of Sunda we have information from the 
steamship SimUiy Captain M. Nicholson, where dust, falling at a distance of about 
1,150 English miles from the volcano, was collected, and from the barque Jonc^ 
Captain L. Reid, at about 600 English miles from the Strait. On board the British 
ships Earl of Beaconsjield, and the Ardgotvan, Captain Isbisteb, and the German 
brig Catheriney dust fell when they were between 900 and 1,100 English miles 
from Krakatoa ; and on board the British barque Arabella, Captain Williams, when 
about 1,100 English miles from Krakatoa. 

The mail steamer Frins Frederik, on its way to Holland, passed near Krakatoa 
on the 25th of August, and the steamer Batavia sailed from Padang to Vlakke 
Hoek on the evening of the 27th. 

The Frins Hendrik, a Dutch man-of-war, was ordered to the Strait of Sunda 
immediately after the eruption, in order to succour the survivors. 

H.M.S. Magpie, Commander the Hon. F. C. P. Vereker, was at Sandakang, 
N. Borneo, at the time of the eruption, and on the 18 th of October visited the Strait 
for the purpose of examining the changes which had taken place. Somewhat later 
H.M.S. Merlin, Commander R. C. Brunton, visited the locality, and sent in a report 
to the Admiralty. 

From various ports, accounts have been received, sent by British Consuls and 
by residents, and many of these have proved to be of great service to the Krakatoa 
Committee. 

The log-books of the different vessels mentioned, and narratives written by the 
captains and passengers on board of them, taken in conjunction with the reports 
collected with so much care by Mr. Vgirbeek, have afforded the means of compiling 
the following account of what occurred at Krakatoa during Sunday, the 26th, and 
Monday, the 27th, August. 

The vessels passing through the Strait, as well as the observers on land, all 
reported a very marked though gradual increase in the violence of the eruption 
during the three days which preceded Sunday, the 26th of August. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 19 

On that day, about 1 p.m., the detonations caused by the explosive action 
attained such violence as to be heard at Batavia and Buitenzorg, about 100 English 
miles away. 

At 2 p.m. Captain Thomson, of the Medea, then sailing at a poiut 76 English 
miles E.N.E. of Krakatoa, saw *' a black mass rising up like a smoke, in clouds," to an 
altitude which has been estimated as being no less than 17 miles. If this estimate be 
correct, some idea of the violence of the outburst can be formed from the fact that 
during the eruption of Vesuvius in 1872 the column of steam and dust was pro- 
pelled to the height of from only 4 to 5 miles. 

The great detonations at this time were said to be taking place at intervals of 
about ten minutes. 

By 3 p.m. the sounds produced by the explosions at Krakatoa had so far increased 
in loudness that they were heard at Bandong and other places 150 miles away; and at 
5 p.m. they had become so tremendous that they were heard all over the island of 
Java, and at many other equally distant localities. At Batavia and Buitenzorg they 
were, during the whole night, so violent that few people in the district were able 
to sleep ; the noise is described as being like the discharge of artillery close at 
hand, and as causing rattling of the windows and shaking of pictures, chandeliers, 
and other hanging bodies. Nearly all observers agree that there was nothing in the 
nature of earthquake-shocks, but only strong air-vibrations. 

Captain Watson, of the Charles Bal, who was only 10 miles south of the 
volcano during this Sunday afternoon, describes the island as being covered with a 
dense black cloud ;" clouds or something were being propelled from the north-east 
point with great velocity ; " sounds like discharges of artillery at intervals of a second 
of time, and a crackling noise, probably due to the impact of fragments in the 
atmosphere, were heard ; the whole commotion increasing towards 5 p.m., when it 
became so intense that the Captain feared to continue his voyage, and began to 
shorten sail. From 5 to 6 p.m. a rain of pumice in large pieces, quite warm, fell upon 
the ship. 

Captain Wooldridgk, of the Sir R. Sale, viewing the volcano from the north- 
east at sunset on Sunday evening, the 26th, describes the sky as presenting "a most 
terrible appearance, the dense mass of clouds being covered with a murky tinge, 
with fierce flashes of lightning.'' At 7 p.m., when the dense vapour and dust-clouds 
rendered it intensely dark, the whole scene was lighted up from time to time by the 
electrical discharges, and at one time the cloud above the mountain presented " the 
appearance of an immense pine-tree, with the stem and branches formed with volcanic 
lightning." The air was loaded with excessively fine ashes, and there was a strong 
sulphurous smell. Captain O. Sampson, of the Norham Castle, who was in the same 
neighbourhood, gives a similar account of what he witnessed. The steamer 
G. G. Loudon passed to the north-west and west of the volcano, within a 

distance of 20 or 30 miles ; it was seen to be " casting forth enormous columns 

d2 



20 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

of smoke," and the vessel passed through "a rain of ashes and small bits 
of stone." 

During the night, while the Charles Bed remained beating about on the east of 
Krakatoa, and within about a dozen miles of the island, Captain Watson records 
the phenomena of ** chains of fire, appearing to ascend " between the volcano and the 
sky, while on the south-west side there seemed to be " a continual roll of balls of 
white fire." These appearances were doubtless caused by the discharge of white- 
hot fragments of lava, and their roll down the sides of the peak of Kakata, which 
was still standing. 

The air at this distance, though the wind was strong at the time, was described 
by Captain Watson as being "hot and choking, sulphurous, with a smell as of 
burning cinders ; " masses like " iron-cinders " fell on the ship, and the lead firom a 
bottom of 30 fathoms came up quite warm. From midnight till 4 a.m. explosions 
continually took place, " the sky, one second intense blackness, the next a blaze of 
fire." 

All these details prove conclusively that Krakatoa had arrived at the paroxysmal 
phase of eruption. The explosive bursts of vapour beginning on the afternoon of 
Sunday and continuing at intervals of ten minutes, increased in violence and rapidity, 
and from sunset till midnight there was an almost continuous roar, which moderated 
a little towards early morning. Each explosive outburst of steam would have the 
effect of removing the accumulating pumice from the surface of the melted lava, by 
blowing it into the atmosphere, and the cauldron of white-hot lava would then have 
its glowing surface reflected in the clouds of vapour and dust hanging above. 

The numerous vents on the low-lying parts of Krakatoa, which were recorded as 
having been seen by Captain Ferzenaar on the 11th of August, had, doubtless, by 
this time become more or less united, and the original crater of the old volcano was 
being rapidly emptied by the great paroxysmal explosions which commenced in the 
afternoon of the 26th of August. 

All the eye-witnesses are in agreement as to the splendour of the electrical 
phenomena displayed during this paroxysmal outburst. Captain Wooldridge, viewing 
the eruption in the afternoon from a distance of 40 miles, speaks of the great 
vapour-cloud looking like **an immense wall with bursts of forked lightning at times 
like large serpents rushing through the air," After sunset this dark wall resembled 
a ** blood-red curtain, with the edges of all shades of yellow ; the whole of a murky 
tinge, with fierce flashes of lightning." Captain O. Sampson, viewing the volcano 
from a similar position at the same time, states that Krakatoa " appeared to be alight 
with flickering flamea rising behind a dense black cloud ; at the same time balls of 
fire rested on the mastheads and extremities of the yard-arms." 

Captain Watson states that during the night the mastheads and yard-arms of his 
ship were *' studded with corposants,'' and records the occurrence of "a peculiar pinky 
flame coming from clouds which seemed to touch the mastheads and yard-arms." From 



PROP. JUDD ON THE VOLCANIC PHENOMENA. 21 

the G. G. Loudon, lying in the Bay of Lampong, 40 or 50 English miles north-west 
of the volcano, it was recorded that " the lightning struck the mainmast-conductor 
five or six times," and that ** the mud-rain which covered the masts, rising, and 
decks, was phosphorescent, and on the rigging presented the appearance of St. Elmo's 
fire. The natives engaged themselves busily in putting this phosphorescent light out 
with their hands, and were so intent on this occupation that the stokers left the 
engine-rooms for the purpose, so that the European engineers were left to drive the 
machinery for themselves. The natives pleaded that if this phosphorescent light, or 
any portion of it, found its way below, a hole would burst in the ship ; not that they 
feared the ship taking fire, but they thought the light was the work of evil spirits, 
and that if the ill-omened light found its way below, the evil spirits would triumph 
in their design to scuttle the ship." 

This abundant generation of atmospheric electricity is a familiar phenomenon in 
all volcanic eruptions on a grand scale. The steam-jets rushing through the orifices 
of the earth's crust constitute an enormous hydro-electric engine ; and the firiction of 
ejected materials striking against one another in their ascent and descent also does 
much in the way of generating electricity. 

Up to late in the afternoon of the 26th of August, the phenomena exhibited by 
Krakatoa were precisely similar to those witnessed at every great paroxysmal volcanic 
eruption. But at that time the effects of the somewhat peculiar position of the 
Krakatoa crater began to be apparent. Lying as it does so close to the sea-level, the 
work of evisceration by explosive action could not go far without the waters of the 
ocean finding their way into the heated mass of lava from which the eruption was 
taking place. 

It is often assumed that if a mass of water come into contact with molten lava 
a terrible outburst of steam, producing a great volcanic eruption, must be the conse- 
quence, and some vulcanologists insist that the admission of water by fissures into 
subterranean reservoirs of lava is the determining cause of all volcanic outbreaks. 
But careful observation does not give much countenance to this view. Lava-streams 
have frequently been seen to flow into the sea, and although a considerable generation 
of steam occurred when the molten mass first came in contact with the water, yet 
none of the prolonged effects which are popularly supposed to result from the 
conflict of fire and water were found to occur. The surface of the lava-current 
becoming rapidly chilled, a layer of slowly conducting rock is formed at its surface, 
and then the gradual cooling down of the whole mass ensues, without further 
disturbance. 

By the lowering of the mass lying within the old crater-ring of Krakatoa, and 
the diminution in height of the crater- walls, water would from time to time find a 
way to the molten lava below ; each such influx of water would no doubt lead to the 
generation of some steam with explosive violence, and the production of small sea-waves 
which would travel outwards from Krakatoa as a centre. From the reports made by 



22 PROF. JUDD ON THE VOLCANIC PHENOMENA. 

the oflScials at Anjer and other places on the shores of Java and Sumatra, the produc- 
tion of such waves, which were only a few feet in height, began to be observed about 
5,30 p.m. on Sunday, the 26th of August, and continued at irregular intervals all 
through the night. Towards morning, however, the chilling effects of the water which 
had from time to time found its way to the molten materials below the volcano 
began to be felt, and as a result a diminution in the activity of the volcano is recorded. 

If, as I shall show when I proceed to discuss the nature of the materials ejected 
from Krakatoa, the cause of the eruptive action was due to the disengagement of 
volatile substances actually contained in those matenals, the checking of the activity, 
by the influx into the molten mass of vast quantities of cold sea water, would have 
the same efiect as fastening down the safety-valve of a steam-boiler, while the fires 
below were maintained in full activity. 

The constant augmentation of tension beneath Krakatoa, in the end gave rise to 
a series of tremendous explosions, on a far grander scale than those resulting directly 
from the influx of the sea-water into the vent ; the four principal of these occurred, 
according to the careful investigations of Mr. Verbeek, at 5.30, 6.44, 10.2,* and 
10.52, Krakatoa time, on the morning of August the 27th. Of these, the third, 
occurring shortly after 10 o'clock, was by far the most violent, and was productive 
of the most wide-spread results. 

Although no one was near enough to Krakatoa during these paroxysmal out- 
bursts to witness what took place there, a comparison of the condition of the volcano 
and of the surrounding seas before and after these terrible manifestations of the 
subterranean forces, leaves little doubt as to the real nature of the action. 

In the first place, we find that the whole of the northern and lower portion of the 
Island of Krakatoa disappeared, with the exception of a bank of pumice and one small 
isolated rock, about ] yards square, which was left sttinding above the ocean with deep 
water all round it. This rock consists of solid pitchstone, and probably represents a 
dyke or plug filling the throat of one of the volcanic cones that formerly occupied 
the old crater. At the same time a large portion of the northern part of the basaltic 
cone of Kakata was destroyed and a nearly vertical cliff formed, giving rise to a 
magnificent section which afforded a perfect insight into the internal structure of the 
volcano. {See Plate 11. , Fig. 2.) The depth of the great crateral hollow which was 
produced, where the northern part of Krakatoa formerly rose to heights of from 300 
to 1,400 feet above the sea level, in some places exceeds 1,000 feet below that same 
level. {See Fig. 10, p. 23.) 

In attempting to judge of the effects produced around the flanks of the great 
crater of Krakatoa, we have the two new and very detailed charts prepared by the 
Royal Dutch surveying vessel Hyclrograaf, under Commandant C. van Doorn. 
The first of these was the result of a careful survey made immediately after the 

* GorrespondiDg to the wave mentioned on p. 69 as 9 b. 58 m. Krakatoa time = 2 h. 56 m. G.M.T. 



PEOF. JUDD ON THE VOLCANIC PHENOMENA. 28 

eruption, and was published on October the 26th, 1883, while the second appeared 
somewhat later, after the new Islands of Steers and Calmeyer had been reduced to 



Pig. 10. — Outline of the crater of Krakatoa as it is at the present time. The dotted line indicates the 
portions blown away in the paroxysmal outburst of August, 1883, and the changes in form of 
the flanks of the mountain by the fall of ejected materials upon them, 

sandbanks. These are reproduced as Plates XXXII. and XXXIII. following Part 
III. ; but it is a very unfortunate circumstance that the old charts of the Strait of 
Sunda are far from accurate, and thus considerable difficulty arises when we attempt 
to make an exact estimate of the changes produced by the eruption. {See Fig. 1 1, p. 24.) 

Certain it is that the portion of the Island of Krakatoa which disappeared 
during the eruption was equal to about two-thirds of the original area, the part that 
remained consisting only of the southern moiety of the volcanic cone of Rakata. 
Of this fragment the southern outline, according to the new charts, differs considerably 
from that of the southern shore of the original island, and its height, if the old 
charts can be depended upon, was increased from 2,623* to 2,750 feet. But the top 
and sides of this fragment of the cone of Rakata are so covered by masses of ejected 
materials that the alteration in its form and height are, it appears to me, sufficiently 
accounted for without requiring us to call in any theory of general upheaval of the mass. 

Of the other islands of the group, Poolsche Hoedje (Polish Hat) has entirely 
disappeared; Lang Island has been increased by an addition to its northern extremity, 
and its height above the sea seems to have been augmented, the whole of the 
vegetation that formerly covered it being deeply buried by ejected matters; and 
lastly, Verlaten Island has, by accretions on the side farthest away from the central 
crater, been enlarged to more than three times its former area, while a considerable 
addition has been made to its height. 

In judging of the alterations in the form of the sea-bottom around the Krakatoa 
group, we have to rely upon the few and not very accurate soundings in the old 
chart of the Strait. From a comparison of these with the depths given in the new 
chart, we can scarcely doubt that over a circle with a radius of 10 or 12 miles from 
the centre of the Krakatoa volcano, the sea-bottom outside the great crater has been 
raised by an amount which varies from 10 to 60 feet. Mr. Verbeek concluded 
however, that along a line 8 or 9 miles in length, and extending westward from the 
great crater, an increase of depth has taken place, and this is not improbably due to 
the opening of a fissure on the flanks of the submerged cone. 

• According to Verbeek, the height previous to the eruption was 2,697 feet. After the eruption he 
sajs the height was 2,730 feet, but was reduced by June, 1886, to 2,677 feet. 



24 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



In the so-called New or Sebesi Channel, between Krakatoa and Sebesi Islands, 
the original depth of water was much less than on the other sides of the Krakatoa 



Sea Rwk^> \^.j^ 



Be*»Rlc 



r^^^ 



SEBESI I. 



|:-- •••••-•'?T««T* »«~~«~»,,;,^^^^^ ^JkfM$Un RmL 



^^"^ 



SEBESI CHANNEL '*''""' 



r 



^ 






LANG I. 




^vTST- 



CALUSTER 




KRAK/VTOA I. 



^^SiKlHliKfAli'i'''-''' 



L^ 



OREAT CHANNEL 



Enftlitli Miles. 



■jy^yft' 



Fio. 11. — Map of Krakatoa and the surrounding ulandsj from the Chart prepared immediately after the 
Eruption, Later charts show the islands of Steers and Galmeyer reduced to sandbanks. The shaded 
areas show the form of the islands a^ccording to the old chart. Much of the discrepancy between 
the southern limit of Krakatoa in the two maps is due to the imperfection of the old survey. 
Dotted lines show sand-hanks and lines of breakers, 

group, seldom, indeed, exceeding 20 fathoms ; and several rocks in this channel rose 
above the sea-level. After the eruption it was found that this channel was com- 
pletely blocked by banks composed of volcanic materials, and two portions of these 
banks rose above the sea as islands, which received the name of Steers Island and 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 25 

Calmeyer Island By the action of the waves, however, these islands were, in the 
course of a few months, completely washed away, and their materials distributed over 
the sea bottom. 

The changes which took place in the forms of the islands and in the depth of 
the sea around them, have been supposed by some to indicate a general elevation of 
the islands of the Krakatoa group, accompanied by a great subsidence of the central or 
crateral area. A careful study of these changes in the light of what is known to have 
taken place at other volcanic centres leads me to adopt a wholly different conclusion. 

The action going on within a volcanic vent during eruption is in all essential 
features identical with that which takes place in the throat of a geyser. In both 
cases we have a mass of heated liquid, in the midst of which large quantities of 
gaseous materials are being disengaged so as to escape into the atmosphere as the 
pressure is relieved, and these escaping gases carry up with them portions of the 
liquid in which they have been confined. Now just as the throwing of sods and 
earth into the tube of a geyser, by causing a check in the escape of steam and water 
and thereby leading to an augmentation of the tension of the elastic fluids below, 
gives rise to a more than usually violent explosion, so the interruption to the regular 
ejections going on at Krakatoa, consequent on the chilling of the surface of the lava 
in the vent by inrushes of sea-water, caused a check and then a rally of the pent-up 
force of gases seeking to escape from the molten mass. The serious catastrophic 
outbursts that produced such startling effects both in the air and in the ocean 
appear to me to have been the direct consequences of this " check and rally " of the 
subterranean forces. 

In these last terrible outbursts, in which the volcano rapidly expended its 
remaining force, we are evidently dealing with the breaking up and ejection of solid 
lava constituting the framework of the volcano, and not with the simple dissipation of 
the lava-froth (pumice) as during all the earlier stages of the eruption. That the 
materials were not carried far from the centre of ejection is shown by the fact that 
no falls of coarse materials are recorded from any of the vessels that were within or 
near the Strait at the time, but the bulk of the solid fragments thrown out during these 
great explosions must have fallen back into the sea, upon and immediately around the 
flanks of the volcano itiself. This is proved by the alteration in the forms of the 
islands of the Krakatoa group, and by the change in the height of the floor of 
the surrounding ocean. By these grand explosive outbursts the old crater was 
completely eviscerated, and a cavity formed, more than 1,000 feet in depth, whUe 
the solid materials thrown out froln the crater were spread over the flanks of the 
volcano, causing the alterations in their form which have been noticed.* 

It was the rush of the great sea- waves over the land, caused by the violent 

* It is probable that lateral eruptions contribnted to the alterations produced bj the ejection of 
materialfl from the central crater. 

E 



26 PROF. JUDD ON THE VOLCAKIC PHENOMENA. 

eviscei'ation of the crater of Krakatoa aided by the impact upon the water of the 
Strait of the enormous masses of falling material, that caused the great destruction 
of life and property in the Strait of Sunda. By the inrush of these waves on to 
the land, all vessels near the shore were stranded, the towns and villages along 
the coast devastated, two of the lighthouses swept away, and the lives of 36,380 of 
the inhabitants, among whom were 37 Europeans, sacrificed. The first waves 
reached both the Javan and the Sumatran coasts between 6 and 7 on the evening of 
August the 26th, and these probably mark the time of the first influx of water into the 
igneous focus. A succession of small oscillations of the sea continued all night, but 
the waves that followed the four great explosions of 5.30, 6.44, 10.2, and 10.52 in 
the morning of August the 27th, were undoubtedly the highest and most destructive of 
all. The question of the nature and height of these waves, and the phenomena which 
accompanied them, are discussed in a subsequent part of this report. The areas 
submerged by these great waves is shown on the Chart, Fig. 9, p. 17. 

Early on the morning of August the 27th, another phenomenon began to manifest 
itself. The vast quantity of watery vapour thrown into the atmosphere during 
the afternoon of the 26th and the night of the 26th and 27th of August, had reached 
an excessive height. This height has been estimated by Mr. Joly at 17 and possibly 
even 23 miles, and by M. Fulmmariox at 12]^ miles. This mass of vapour and dust, 
as so graphically described by Captain Wooldridge, of the Sir R, SalCy on reaching 
the limit of its elevation spread itself out laterally, giving rise to the '" pine-tree " 
appearance so familiar to the Itjdians, who are in the habit of watching the 
paroxysmal outbursts of Vesuvius. All night long this great cloud spread itself 
laterally, the particles of dust slowly descending through the atmosphere. Between 
10 and 11 a.m. the three vessels then at the eastern entrance of the Strait 
encountered the fall of mingled dust and water, which soon darkened the air and 
covered their decks and sails with a thick coating of mud. Some of the pieces 
of pumice falling on the Sir R. Sale were said to have been of the size of a pumpkin. 

Between 10 and 10.30 a.m. the same state of things is reported in Lampong Bay, 
the G. G. Loudon being compelled at the latter hour to come to anchor on account of 
the darkness. 

At Batavia, situated about 100 English miles from Krakatoa, the sky was clear 
at 7 a.m., but began to darken between that hour and 10 a.m. ; at 10.15 the sky 
became lurid and yellowish, and lamps began to be required in the houses ; about 
10.30 the first falls from the overhanging clouds took place in the form of fine 
watery particles, and this was succeeded by a few grains of dust ; at 1 1 a,m. this 
increased to a regular dust-rain, becoming heavier till 11.20, when complete 
darkness fell on the city. This heavy dust-rain continued till 1, and afterwards 
less heavily till 3 p.m. The dust fell in small rounded accretions, containing about 
10 per cent, of water. A similar phenomenon is recorded as having been observed 
during the recent eruptions of Tarawera in New Zealand. 



PROF. JCJDD ON THE VOLCAKIC PHENOMENA. 27 

At Buitenzorg, a little farther from the volcano, similar phenomena were 
recorded but were of shorter duration. The dust-fall commenced at 11, but 
darkness did not begin till noon, and it passed away as the dust-fall ceased at 2 p.m. 
The darkness, however, extended- in the country eastward as far as Tjandjer, about 
130 English miles, and Bandong, nearly 150 miles from the volcano. 

The air-waves produced by the great explosions appear to have been of three 
kinda Those which were of sufficient rapidity of alternation to give rise to sounds, 
are recorded as being heard as far away as Rodriguez and Diego Garcia, which 
are respectively 3,080 and 2,375 English miles distant from the volcano. Other 
waves of larger dimensions caused the bursting in of windows, and even the cracking 
of walls 100 miles away at Batavia and Buitenzorg. Lamps were thrown down, 
gas-jets extinguished, and a gasometer, under the influence of one of these great 
waves, leaped out of its well, causing the gas to escape. Even at much greater 
distances cracks were produced in walls, and all accounts agree in ascribing the 
result to air-vibrations and not to earthquakes. 

The air-vibi-ations of still greater w6,ve-length which travelled several times 
round the globe, as was first shown by General Strachey and Mr. Scott, are fully 
discussed in another part of this report, in which also details are given respecting 
the air-waves producing sound. (See Part II., p. 58.) 

Eruptive action appeared to continue in the neighbourhood of Krakatoa during 
the whole of Monday, the 27th, though the darkness which prevailed over the Strait 
of Sunda prevented the exact nature of the operations going on there from being 
determined. Three vessels, the Charles Bal, the Sir R. Sale, and the NorJiam Castle^ 
were all day beating about in the darkness at the eastern entrance of the Strait, the 
pumice-dust falling upon them in such quantities as to employ the crews for hours in 
shovelling it from the decks and in beating it from the sails and rigging. On board 
the G. G. LoudoUy anchored in Lampong Bay, it is recorded that, after the rain of 
pumice-stone in the early morning, only dust and water fell in the form of mud, which 
accumulated on the deck at the rate of 6 inches in 10 minutes. Frequent explosions 
and vivid lightning in the neighbourhood of Krakatoa are recorded. After the great 
outbursts of the early morning of the 27th, however, it appears that there was 
a lull for a time, as at Buitenzorg no explosions were heard during the afternoon 
till 7 p.m. At this latter hour the explosions, as heard from Buitenzorg, recom- 
menced, increasing in violence till 10 or 11 p.m., when they again declined, and finally 
ceased to be heard at 2.30 a.m. on Tuesday, the 28th of August. 

On Wednesday, the 29th of August, the G. G. Loudon forced her way through 
the pumice-laden seas passing from the Bay of Lampong through the Strait of 
Lagoendie, and then sailed round the west, south, and east sides of Krakatoa, and 
thence on to Anjer, which place was reached at 4 p.m. They found that the whole of 
the northern part of the island of Krakatoa had disappeared, and that no smoke was 
at that time issuing from it. It was seen, however, that between Krakatoa and Sebesi 

E 2 



28 PROF. JUDD ON THE VOLCANIC PHENOMENA, 

" a reef had formed, and that various craters planted on that reef were sending columns 
of smoke on high." 

On Wednesday, 29th, and Thursday, 30th, the Sir R. Sale and Norham Castle 
were working through the Strait from the east, afud on the latter day were within 
ten miles of Erakatoa. Neither of the captains reports any kind of activity at 
Krakatoa, nor did either perceive the changes which had taken place in the island. 

The steamer Anerley passed through Sunda Strait from the east on Tuesday the 
28 th ; she kept close to the Java shore, and reports no eruptions as taking place at 
Exakatoa. The peak of Krakatoa was seen to he in its usual position, and no change 
was noticed in its form, or in that of other parts of the island. 

Neither the captain of the Berhice, nor of the Wm. H. Besse, which passed 
through the Strait from the west and east respectively on August the 29th and 30th, 
reports any kind of action as being heard on those days in the direction of Erakatoa. 

Those on board the Prins Hendrik, which entered the Siuida Strait on 
September the 3rd, noticed that from the part which remained of £j:ukatoa, from 
Lang and Verlaten Islands, from Steers and Calmeyer Islands, smoke continually 
arose, and now and then a flame was seen at night. 

Commander Doorn of the Hydrograaf has suggested, from his inspection 
of the locality at a later date, that the steam proceeding from the hot pimiice 
had been mistaken for eruptive outbursts, but there are some grounds for believing 
that lateral eruptions did take place on the flanks of Erakatoa after the outburst 
from the central crater had entirely ceased. 

The soundings after the eruption indicate, as already pointed out, that a great 
depression or fissure had been formed in the sea-bottom, extending eastward of 
Erakatoa for a distance of about 7 or 8 miles, and extending nearly in the direction 
of the great line of volcanic activity which traverses Java and Sumatra. The 
formation of the islands of Steers and Calmeyer appears to be most naturally 
accounted for if we imagine that two or more parasitical volcanic cones had grown 
up on the northern flank of the Erakatoa volcano and had increased in size till 
they rose above the sea-level. In this state they appear to have been seen by 
those on board the G. O. Loudon on August the 28th ; and in a later stage of 
degradation by those on board the Prins Hendrik, on the 3rd of September* 
These cones of loose pumice on rising above the sea-level were soon attacked by 
the waves, and as in the analogous well-known cases of Graham's Island and 
Sabrina, were gradually reduced first to sand-banks and then to shoals.* 

* The excessive quantity of material which mnst have been deposited in the channel between 
Erakatoa and Sebesi, to cause the formation of the two new islands and the snrroTmding shoals, has 
given rise to the suggestion that large portions of the volcano were actually hurled bodily into the air, 
and fell into the chfumel in question. But it is not necessary to adopt so improbable an hypothesis 
as this, when we remark the frequency of lateral eruptions upon volcanoes, and that we have in this 
case some direct evidence that small parasitical cones did actually exist at this point immediately 
after the great outburst. 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 29 

There is considerable doubt as to whether several small eruptions did not occur 
in and about Krakatoa after the great outburst had died out on the 28th or 29th 
of August. The investigations by Mr. Verbeek, however, have established the fact 
that a not inconsiderable explosion, accompanied by a rumbling sound, the ejection 
of large quantities of black mud, and a heavy sea- wave certainly took place at 9.30 p.m. 
on the 10th of October. The materials thrown out in this last exhibition of activity 
were afterwards clearly seen covering the slopes of the peak of Krakatoa, and the 
Island of Calmeyer, and the outburst must have been a by no means insignificant one. 

Judged of by the quantity of materials ejected, or by the area and duration 
of the darkness caused by the volcanic dust, the eruption of Krakatoa must have 
been on a much smaller scale than several other outbursts which have occurred 
in historic times. The great eruptions of Papandayang in Java, in 1772, of 
Skaptar JokuU (Varmdrdalr) in Iceland, in 1783, and of Tomboro in Sumbawa, in 
1815, were aU accompanied by the extrusion of much lai^er quantities of material 
than that thrown out of Krakatoa in 1883. The special feature of this last 
outburst of the volcanic forces was the excessively violent though short paroxysms 
with which it terminated. In the terrible character of the sudden explosions 
which gave rise to such vast sea and air-waves on the morning of the 27th of 
August, the eruption of Krakatoa appears to have no parallel among the records 
of volcanic activity. The peculiarity of the phenomena displayed during this 
eruption is, I believe, to be accounted for by the situation of the volcano, and its 
liability to great inrushes of the waters of the sea, as the evisceration of the 
crater opened a way to the volcanic focus. The manner in which these influxes 
of cold water would first moderate the volcanic action, and as a consequence 
give rise in the end to tremendous and exhaustive explosions of abnormal violence, 
I have already endeavoured to explain. 



II. The Materials ejected from Krakatoa. 

As some very remarkable atmospheric phenomena appear to have followed the 
great outburst of Krakatoa, and these have been thought by many authors to have 
owed their origin, either directly or indirectly, to materials thrown into the higher 
strata of the gaseous envelope of our globe by these prodigious explosions, it may be 
well to inquire as to the exact nature and state of division of the substances which 
are known to have been ejected from the volcano. 

Great facilities are afibrded to us for studying the rocks of which Krakatoa was 
built up, by the magnificent sections produced during the great final outbursts. A 
fine volcanic cone, between 2,000 and '3,000 fe^t in height, had nearly half of its 
mass blown away, and the almost perpendicular precipices which were thus fortned 



30 PEOF. JUDD ON THE VOLCANIC PHENOMENA. 

exhibit a wonderM succession of lavas and tufis, the whole bound together by a 
network of vertical and oblique dykes. Never, perhaps, have geologists had so 
splendid an opportunity of studying the internal architecture of a compound 
volcanic cone, as that which has been afforded to them in the splendid ruin of Rakata. 
{See Plate II., Fig. 2.) The remaining slopes of the cone of Rakata are thickly 
buried under masses of pumice and other ejected materials, in which streams have 
cut deep radiating ravines. {See Plate II., Fig. I.) 

Underneath this ruin of the cone of Eakata, the older rock-masses of the island 
are seen making their appearance. I am much indebted to M. Reni^ Br^n, who 
visited the district a few months after the great eruption, for carefully selected 
specimens of all the different types of rock exhibited in the interior of Krakatoa. 

T/ie Lavas. 

The great bulk of the old crater-ring of Ejrakatoa is made up of massive 
outflows of an enstatite-dacite, which was found, on analysis, to contain 6 9 '7 4 
per cent, of silica. While the minerals contained in this rock are, on the whole, 
similar to those of the enstatite-andesites so abundant in Java and Sumatra — 
namely, plagiodase felspar, ferriferous enstatite (hypersthene), augite, and magnetite 
— the proportion of the base to the included crystals appears to be very different 
in the two cases. The Krakatoa-rock contains at least 90 per cent, of base to 
10 per cent, of crystals ; and as this base is of a much more acid character than 
the crystals themselves, the Krakatoa rock has a silica percentage of 70, while the 
ordinary andesites of Java and Sumatra, which contain a very much smaller 
proportion of base to included crystals, contain only between 52 and 6 1 parts in 
100 of silica. {See Plate III., Fig. 1.) We have here a very instructive illustration 
of the necessity of taking into account, not only the species of minerals contained 
in a rock, but the propoi*tions in which they are present. A rock of very similar 
character to that so abundant at Krakatoa was described as occurring at Java's 
First Point and Princes Island by MM. Vbrbebk and Fennema, and such highly 
acid varieties were, perhaps, characteristic of the ejections from the transverse 
fissures of the Strait of Sunda. 

These older lavas are sometimes compact and at other times vesicular. In 
the latter case the cavities are remarkable for the fine crystals of tridymite, 
sometimes accompanied by hornblende and quartz, which they contain; these 
have been described and %ured by Professor VoM Rath. * The crystals of 
tridymite appear to me to be of secondary origin, and to have been developed in 
the cavities of the rock by the passage of acid vapours. 

The base of these old lavas, which is of a reddish-brown colour, is seen under the 

* ' VerhandluBgen des natnrli. Vereitis de preuss. Rheinl. tl. Wesfcf.,' 1884, pp. 326-333. Taf. 
v5., flg. 18 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 31 

microscope to consist of glass crowded with microlites of felspar, augite, enstatite and 
magnetite, the latter often converted into flecks of hydrous-brown oxide which give 
the rock its peculiar tint. What are believed to be microlites of tridymite have also 
been described as occurring in the base of the rock. {See Plate III., Fig. 2.) The 
porphyritic crystals of felspar, enstatite, augite, and magnetite are similar to those 
found in the later rocks of Krakatoa, which will be noticed more ftdly hereafter. 

In the walls of the old crater-ring of Krakatoa (as at Polish Hat and the 
south end of Lang Island), and among the materials that have been ejected 
within it, there are found also some very interesting porphyritic pitchstones of a 
velvety-black colour. These rocks are proved by analysis to have precisely the 
same chemical composition as the associated stony lavas. The included porphyritic 
crystals are also precisely the same. These rocks, except for the proportion of the 
glassy base to the crystals, bear a very striking resemblance to the "porphyritic 
pitchstones" of the Cheviot Hills which have been made so well known to 
petrologists by the descriptions of Mr. Teall and Dr. Peterssen. The glassy 
base of these rocks is of a rich brown colour by transmitted light, and is crowded 
with microlites, a beautiful fluidal structure being often exhibited in it. {See Plate III., 
Fig. 4.) In certain parts of the Cheviot Hills I have found a stony lava very 
similar in appearance to that forming the bulk of the crater-ring of Krakatoa, 
passing at the surfaces of the lava-streams into the well-known velvety -black 
porphyritic pitchstone of the district, and it is probable that similar relations exist 
between the analogous rocks at Krakatoa. With these lavas only very insignificant 
beds of tuff have been found associated. 

The next lavas ejected at Krakatoa present a very striking difference from those 
just described. They are seen in the great lateral peak of Rakata, which was built up 
by a succession of eruptions from a vent opened on the edge of the great crater. 
The unconformity of these basaltic lavas, and of the tuffs of the same composition 
alternating with them, to the older dacites is well seen in the great natural section 
produced by the eruption of 1883. {See Plate II., Fig. 2.) These basalts do not offer 
much subject for remark ; some appear to contain much greater proportions of olivine 
than others, and there are variations in the degree of crystallization of the materials. 
A specimen which was analysed gave a percentage of 48*81 of silica. 

With the eruption of the materials which covered the lower and northern part 
of Krakatoa we find a return to the earlier types of lavas. They all consist of 
enstatite-dacites with about 70 per cent, of silica. Indeed the ultimate chemical 
composition, and the nature of the porphyritic crystals embedded in these youngest 
lavas are so similar to those of the earliest period, that the re-fusion and outwelling 
of some of the lower portions of the mass are very strongly suggested by their 
study. 

Concerning the materials thrown out during the last eruption of Krakatoa, we 
have fortmiately a large number of valuable observations made both by chemists and 



32 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



by mineralogists ; and the study of these materials is, I believe, calculated to cast 
much new light upon certain vulcanological problems. 

Mr. Verbeek computes that of the materials thrown out between May the 20th 
and the period when the whole solid framework of the interior of the volcano was 
blown up, at least 95 per cent, consisted of pumice and dust, and not more than 5 per 
cent, was made up of compact lava and of fragments torn from the side of the vent. 
As the pumice and dust were all formed, as we shall see, from the compact lava, it 
will be convenient to describe this at the outset. 

The compact lava of 1883 presents itself under two diflferent forms, the distinc- 
tions between which are worthy of the most carefiil study. These two rocks may 
be characterised as porphyritic pitchstone, and porphyritic obsidian. In both these 
the crystalline elements are the same, and constitute only about 10 per cent, of the 
whole bulk of the rock. Of these crystalline elements felspar constitutes about 
two-thirds, crystals of pyroxene about one-third as much as the felspar, and magnetite 
about half the bulk of the pyroxenes. The crystals do not appear to be scattered 
by any means uniformly through these rocks, but little groups, each containing a 
number of crystals of felspar, pyroxene, and magnetite are found at intervals in the 
ground-mass. The pyroxenes include the two different forms, a rhombic pyroxene or 
enstatite, and a monoclinic form or augite ; the former appearing to be about twice 
as abundant as the latter. In addition to the essential minerals of the rock, apatite, 
pyrite, and pyrrhotine (magnetic pyrites) were found to occur in small quantities as 
accidental or accessory constituents. Perhaps the most striking feature of these 
rocks is the large proportion borne by the base to the crystalline elements diffused 
through it. 

The average composition of this rock is probably well represented by an analysis 
made by Professor C. Winkler, of Freiberg, in Saxony, of a mass of the Krakatoa 
pumice, collected by Mr. Verbeek upon the island on October the 16th, 1883. Its 
specific gravity was found to be 2-329. Omitting the moisture and substances soluble 



composition was loi 


ana to 


be as ic 


allows :— 


- 




Silica 




68-99 


Titanic acid 










0-82 


Alumina ., 










16-07 


Ferric oxide 










2-63 


Ferrous oxide 










1-10 


Manganous oxide. 










0-28 


Lime • • 










3-16 


Magnesia . . 










1-08 


Potash 










1-83 


Soda 










4-04 




100 00 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



S3 



Mr. J. W. Retgebs, of Buitenzorg, taking the dust which fell at that place, 
which was very carefully collected so as to avoid accidental admixtures, and employing 
the most delicate and refined methods for separating the particles of glass from those 
of crystalline minerals, and the several varieties of the latter from one another, has 
been able to isolate and analyse the several constituents of these rocks. His results 
are given in the following table. The optical and other characters of the minerals of 
these rocks, as exhibited in the dust derived from them, also have been studied by 
Richard,* RENARD,t Sauer,J H. H. Reusch,§ OebbkkeJ Von Lasaulx,! Carvtll 
Lewis,** JoLY,tt Waller,^!: R. BRfiON,§§ and myself, |||! as well hs by MM. Verbeek, 
Rexgers, and Winkler. If H 





Glass. 


Felspae. 


Enstatitb. 


AfGlTE. 


Magnetitk. 




(All materials 












having a 


Average of 


Highly 








specific 


all kinds 


ferriferous. 




(With 




gi^avity less 


present. 


(Amblyste- 




Ilmenite.) 




than 2G.) 




gite). 






Silica 


68-12 


58-29 


52-3 


48-6 




Titanic Acid 


0-18 


— 


— 


— 


6-7 


Alumina . . 


15-81 


27-19 


6-1 


8-2 


— 


Ferric Oxide 


) 5-01 


— . 


— 


— 


66-0 


Ferrous Oxide 


— 


27-7 


14-0 


37-3 


Manganoas Oxide 


— 


— 


trace. 


— 


— 


Lime 


2-78 


8-27 


2'2 


18-9 


— 


Magnesia . . 


1-18 





13-6 


11-6 


— 


Potash 


1-06 


1-22 


— 


— 


— 


Soda 


5-09 


6'82 


— : 




— 




y9-23 


100-79 


101-9 


101-3 


lOO-O 



With respect to the felspars of those rocks, MM. Verbeek and Retgebs have 
arrived at the interesting conclusion that all the varieties of plagioclase are present 
together in the same mass. They conclude that 85 per cent, of the felspar-crystals, 



• ' Comptes Rendus.' Seance du 19 Novembre, 1883. 

t 'Bnll. de I'Acad. Royale de Belgique/ 3itoe Ser., t. vi., 1883. 

X * Berichte der Natnrf . Gesellsch. zn Leipzig,' 1883, p. 87. 

§ *Nenes Jahrb. fiir Min.,* Ac, 1884, I. Bd., p. 78. 

II * Nenes Jahrb. liir Min.,' Ac, 1884, II. Bd., p. 32. 

T *Sitzg. d. niederrh. Ges. in Bonn' (Sitzg. vom 3 December, 1883). 

•• ' Proc. Acad. Nat. So.,' Philadelphia, 1884, p. 185. 

tt * Royal Dablin Society,' N.S., vol. 4, p. 291. 

XX * Birm. Nat. Hist, and Microscop. Soc, Rep. and Trans, for 1883,' p. vi. (March 4th, 1884J. 

§§ 'La Nature,' 13«^« Annee (1885), p. 373. 

nil 'Nature,' vol. xxix., p. 595. 

It * Krakatau,' pp. 185-324. 

F 



^i PROF. JUDD ON THE VOLCAXIC PHENOMENA. 

however, are llrae- soda felspars, intermediate between the very acid and the very basic 
types, and would, according to the ordinary mineralogical nomenclature, be ranked 
as labradorite, andesine, or oligoclase. Smaller quantities of anorthite, albite, and 
potash-plagioclase (anorthoclase of Rosenbusch), also are found in the rock. These 
results are of very great interest to petrographers. Many rocks have been shown to 
contain felspars belonging to more than one species ; the felspars of the first and 
second consolidation in a rock, indeed, usually differ considerably in composition. In 
the same crystal, too, we may find a number of successively formed zones, having 
different chemical composition and optical properties ; and crystals of plagioclase mar 
be found actually surrounded by a zone of orthoclase. Never, however, as far bs I 
am aware, has so great a diversity of felspar-crystals been recorded in the same rock 
as in that of Krakatoa. It must be remembered, however, that the conclusion of 
MM. Verbeek and Retoers is founded, not on the study of a rock itself, but on 
the dust produced by the comminution of great masses of rock in which considerable 
diversity of mineralogical constituents may have existed The felspar-crystals of the 
Krakatoa-rocks are usually remarkable for the striking zoned structure exhibited by 
the individual cr}-stals. 

The enstatite of these rocks is of a deep tint and highly pleochroic According 
to the analysis of M. Ketgers, indeed it must be regarded as containing a higher 
percentage of iron than the ordinary hypersthenes ; and if we follow the nomen- 
clature which I have suggested for the varieties of enstatite, it should be classed 
as an amblystegite. 

The augite, which is aluminous and contains a high percentage of lime, is of a 
pale olive-green tint and exhibits only a very feeble pleochroism. Examples of 
intergrowth of the monoclinic augite and the rhombic enstatite, the corresponding 
axes of the two crystals being in parallel positions, are not unfrequent. 

In addition to magnetite, in these rocks there have been found ilmenite, pyrite, 
pyrrhotine, apatite, and some secondary products. 

There ia often a marked contrast between the porphyritic felspar-crystals embedded 
in the two types of glassy dacite rocks. In the obsidians, the crystals of felspar 
have sometimes perfectly sharp outlines ; they contain glass-cavities, often with the 
rectangular outlines of negative crystals, containing gas bubbles. The broMTi glass 
filling these cavities is much darker in colour than the glass of the ground-mass, 
though traces of a similar brown glass are often seen adhering to the sides of the 
knots of crystals {See Plate III., Fig. 5). The crystals are not unfrequently broken, 
and are sometimes bent; in the latter case the development of the lamellar twinning in 
them is seen to have been determined by the strain to which they had been subjected. 

In the pitchstones, the felspar-crystals more frequently have their angles and edges 
rounded, and through the whole of their interior a great amount of corrosion has 
taken place, so that the crystals now appear as mere skeletons, the glass which has 
eaten into the crystals being much greater in bulk than the crystalline material that 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 35 

remains. In eating into the substance of the crystals the corrosive material has 
evidently taken advantage of planes of chemical weakness in the crystals ; but it 
is remarkable that in many cases there is an outer zone which remains almost intact. 
{See Plate III, Fig. 3.*) 

Let us now turn our attention from the crystals scattered through these rocks, 
to the base, or ground-mass, in which they are embedded. 

The porphyritic pitchstone of the 1883 eruption appears to be almost absolutely 
identical in its characters with the older material already referred to as forming Polish 
Hat Island, and also occurring at the south end of Lang Island and other points in the 
old crater-ring. (See p. 31.) It is black and perfectly opaque, except in very thin sec- 
tions, and has a resinous lustre. Under the microscope the base of the pitchstones 
is seen to be formed of a felted mass of microlites of felspar and pyroxene, with grains 
of magnetite, and the whole mass has its interstices filled with a yellowish or brown 
glass. The base often exhibits a banded or fluidal structure. {See Plate III., Fig. 4.) 

The porphyritic obsidian on the other hand has a strikingly vitreous lustre. By 
reflected light it is of a very dark brown, nearly black, colour ; by transmitted 
light, of a rich yellowish-brown tint ; while in thin sections it is almost colourless. 
In the midst of this glass may be seen a very few scattered microlites of ftkpar 
and pyroxene, these bearing but a very small proportion indeed to the glass in 
which they are enclosed, and in this respect the obsidians offer a very striking contrast 
to the pitchstones above described, {See Plate III., Fig. 6.) 

Occasionally, however, rocks are found which are intermediate in the characters 
of their base between the obsidians and the pitohstones. 

The most striking differences between these two rocks are seen, however, when 
they are subjected to a high temperature. Before a gas-flame, urged by a foot-blast, 
the pitchstone is found to decrepitate, but to undergo fusion only with the greatest 
difficulty. The obsidian, on the other hand, is fused with comparative ease, and 
during fusion, bubbles and swells up into cauliflower-like masses, which will float on 
water. These white cauliflower-shaped masses have exactly the colour and appearance 
of the pumice ejected from Krakaloa, and on making thin sections of them and 
comparing them with sections of the Krakatoa-pumice, their structtu'e is found to be 
almost absolutely identical. {See Plate IV., Fig. 4.) The loss suffered by the pitch- 
stones on ignition is almost nil, while the obsidians lose from I, to 5 or 6 per cent, of 
their weight. 

In the case of the curious marekanite of Siberia, and of a mica-dacite glass 
from Fifeshire, I have already pointed out the tendency of glasses containing large 
quantities of water to undergo fusion at comparatively low temperatures, and while 
doing so to part with their volatile ingredients, becoming thereby converted into 
pumice.t 

• The Plates IT., III.,' and IV. will be found at the end of tbis Part, i.e., after p. 56. 
t ' Quart. Jour. Geo. Soc.,' vol. xlii. (1886), p. 429 ; * Gaol. Ma^.,' Doc. iii., vol. iii. (1S86), p. 243. 

F 2 



3G PROF. JUDD OX THE VOLCANIC PHENOMENA. 



Tfie Pumice. 

The pumice which was thrown out in such enormous quantities during the latest 
eruption of Krakatoa, was evidently formed by the disengagement of volatile matters, 
throughout the whole substance of this obsidian. The formation of this pumice can 
indeed be exactly imitated if we take a strong solution of bicarbonate of soda, 
rendered slightly viscous by the addition of gum, and made neaily opaque by the 
addition of some brown colouring matter, and allow an acid to diffuse itself through 
the mass. The carbonic acid, as it becomes disengaged, will distend the whole 
mass to five or six times its original bulk, owing to the formation of gas bubbles 
in its midst, and we get a white mass of froth exactly resembling pumice. Nothing 
can be more certain than the fact that the volatile substances which, escaping in 
puch quantities from the vent of Krakatoa, gave rise to the last eruption, were 
originally imprisoned in every part of the glassy mass. The whole of the pumiceous 
substance is penetrated with the finest vesicles produced by the disengagement of 
gas. Those fragments of the lava which had cooled so far as to become con- 
solidated before ejection, only require ^to be heated in order to give off their volatile 
ingredients ; and in doing so the melting glass is converted into a true pumice. In 
what condition water and other volatile substances exist in these glassy rocks is still 
to some extent an unsolved problem. Such rocks may lose from 1 to 10 per cent, 
on ignition. It is certain, however, that the water or other substances do not exist 
in any cavities visible under the highest powers of the microscope, and it is probable 
that they are in actual combination with the glass or colloid body. 

The presence of from 3 to 16 per cent, of water in opals or colloid silica, is probably 
a perfectly similar case. Colloid bodies appear to have this power of taking up 
and of retaining large quantities of water and other volatile substances. The diflSculty 
of removing the last traces of water from precipitated colloid silica is very well 
known. 

The pumice of Krakatoa is found presenting two different varieties. By far the 
rarest of these is a perfectly white material of very fibrous texture, closely resembling 
the well-known pumice of Lipari. In this variety porphyritic crystals do not appear 
to be present. I received a specimen of this variety from Mr. H. O. Forbes, to whom 
it was given by one of the party from Batavia that visited Krakatoa on May 27th, 
1883 ; the mass, which was about 2 J inches in diameter, was among the frag- 
ments thrown out during the earliest stage of the eruption. (See Plate IV., Figs. 
1 and 2.) 

The great mass of the pumice thrown out during the eruption, however, presented a 
dirty greyish-white tint, the air-pores in it being very irregular in size, and sometimes 
large. Scattered all through the mass are little knots of crystals of felspar, pyroxene, 
and magnetite, distributed at somewhat wide intervals. When, as wa^ usually the 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 37 

case, the pumice was rounded, either by the striking of fragments in the air or by 
their attrition while floating on the ocean, the little knots of crystals, on account of 
their superior hardness, stand out like warts on the surfaces of the masses. In 
addition to these knots of crystals there are sometimes found little fragments of 
black glass, and these, when examined in thin sections, are seen to be composed of 
the pitchstone already described, often containing the usual porphyritic crystals, 
which are in such cases remarkably coiToded. (See Plate IIL, Fig. 3.) 

The formation of this pumice by the escape of imprisoned volatile matters in the 
obsidian, while it was still in a viscous condition, is abundantly illustrated if we 
examine its structure microscopically ; the glass is seen to be drawn out into plates 
and threads of all dimensions. {See Plate IV., Figs. 1, 2, 3.) In specimens of pumice 
wluch were collected on Krakatoa, and had not been immersed in the sea-water, the 
microscope often reveals delicate fibres of spun glass running from one side of a 
cavity to the other, and these are frequently of the smallest dimensions which can 
be recognised by the microscope. In this connection we may recall the ingenious 
experiments of Mr. C. V. Boys, who has managed to draw out threads of glass of 
ultra-microscopical dimensions ; the existence of which could be proved, however, by 
their diffraction effects.* That similar ultra-microscopical threads were formed in the 
cavities of the Krakatoa -pumice we have every reason for believing. 

In order to determine the amount of distension which the ol^sidian underwent in 
its conversion into pumice, rectangular blocks of the latter substance were cut and 
careftiUy measured and weighed. The tine-grained, very dense, white pumice was found 
to have nearly three and a half times the volume of the glass out of which it was 
formed ; and the much more common dirty-grey pumice was found in average 
examples to have undergone a dilatation to five and a half times its original bulk, and 
this in spite of the fact that something like one-tenth of the original lava consisted 
of undilatable crystals, which remained to weight the mass. Owing to the existence 
of the heavy crystals diffused through it, and the fact that water enters it to some 
extent by the large open pores, the ordinary Krakatoa pumice was found to float 
with two-thirds of its bulk submerged and one-third above the water. Much of 
the pumice, in which the air-cells were exceptionally large, was far more bulky in 
proportion to its weight ; and some of these pieces projected to enormous heights 
in the atmosphere, appear to have been swept great distances by air-currents before 
they finally fell into the sea. 

The study of the pumice of Krakatoa shows that the greater part of the glass of 
which it is composed depolarises light to a greater or less extent. It is evident, 
therefore, that it is in a condition of intense strain, the result of the rapidity with 
which it cooled. To the same cause must probably be ascribed its extreme brittleness, 
for it can be easily crumbled between the fingers. 

In addition to the analysis of the pumice of Krakatoa published by Professor C. 

•- * Phil. Mag.,' Series V., vol. xxiii. (1887), p. 489. 



38 



PROF. JUDD OX THE VOLCANIC PHENOMENA. 



Winkler, of Freiberg, I add the following, which has been kindly furnished to me 
by Mr. T. H. Waller, of Birmingham : — 



Silica 






69 4 


Alumina 






15-9 


Ferric oxide 






1-2 


Ferrous oxide 






2-2 


Lime 






3-4 


Magnesia . . 






11 


Soda 






4-2 


Potash 






2-3 


Loss on ignition 






10 



100-7 



The chloride of sodium and other soluble matter with which the pumice was 
impregnated from floating in sea water was removed by washing before this analysis 
was made. 

As far as I have been able to determine, the pumice ejected from Krakatoa 
before and during the last violent stage of the eruption was identical in character. 
As this material was being thrown into the sea during nearly four months, it is 
impossible to determine at what date any particular specimen found in the ocean may 
have started on its journey, and consequently the hope of determining the direction 
ami rate of the marine currents by which they were distributed must be abandoned. 
It may be added, that as the Krakatoa- pumice floats with so large a portion of its 
mass above the water, prevalent winds might have much influence in determining or 
modifying its movements. 

Dr. C. Meldrum, F.RS., of Mauritius, had special facilities for collecting 
observations on the subject of the distribution of this pumice, and his notes on the 
subject, which were presented to the British Association, were published in 1885. 
They are reproduced as an Appendix to this report, together with a Memorandum on 
the subject by Mr. Robert H. Scott, F.RS. (pp. 47, 48). 



The Volcanic Dust. 



Let us now proceed to the study of the volcanic dust which was formed in 
such enormous quantities during the Ejrakatoa eruption. 

That steam escaping from a mass of molten glass may carry off fine particles of 
the substance, often dragging it out into threads, appears highly probable. That such 



PROF. JUDD OX THE VOLCANIC PHENOMBXA. 39 

is actually the case I was able to prove by heating the little obsidian-balls known as 
" marekanite," when clouds of finely-divided particles were seen to be driven off from 
its mass. But the great bulk of the volcanic dust of Krakatoa was undoubtedly formed 
by the striking together of fragments of pumice as they were violently ejected from 
the crater and fell back again into it. The noise made by this hurtling of fragments 
in the air was remarked upon by several observers, and as I have myself noticed at 
Stromboli, is often more striking than the sound of the explosions. The action of 
this " dust-making " mill, as an active volcano undoubtedly is, was well illustrated 
during the Vesuvian eruption of 1822. Mr. Scrope, who was an eye-witness of that 
eruption, describes how day after day as the eruption proceeded ^the dust-particles 
became finer and finer, till at last they were able to penetrate the finest cracks, finding 
their way into and filling all locked boxes, drawers, and similar receptacles. 

The extreme brittleness of the glass of the pumice, which I have before remarked 
upon, as the result of its sudden cooling, would facilitate its pulverization ; and as 
it was reduced to powder it would remain longer in the atmosphere, and be swept 
ferther away from the central ascending steam-column. The large fragments of 
pumice would be re-ejected again and again as they fell back into the crater, each 
time being* reduced in bulk and weight. All the ejected blocks of pumice bore 
obvious marks in their rounded form of this attrition in the air, and the work of 
rounding and reduction in bulk went on after they reached the ocean, and were swept 
by currents and driven by winds. 

If a piece of the Krakiatoa pumice be pounded in a mortar, and the dust so formed 
be mounted and examined microscopically, it will be found to agree in the form of 
its particles and its general characters with the volcanic dust which fell at so many 
points around the volcano. (See Plate IV., Fig. 6.) 

Through the kindness of many correspondents I have had the opportunity of 
studying a very large number of samples of the Krakatoa-dust, collected from many 
points, ranging from 40 to 1,100 English miles away from the volcano. 

Even to the naked eye, striking differences are manifest among these various 
specimens. Those collected nearest to the volcano obviously consist of coarser 
particles, and they are of a somewhat darker tint owing to the greater abundance in 
them of fragments of crystals, especially those of magnetite and other dark -coloured 
minerals. Those dusts which were collected at the greatest distance from the volcano 
were excessively fine and almost perfectly white in colour. Professor Winkler 
describes the dusts which fell at Krakatoa as having a darker tint and a higher 
specific gravity than those which fell at Buitenzorg. 

Under the microscope the differences between the dusts collected at different 
points come out in a very striking manner. 

A considerable number of analyses of the Krakatoa dust have been made by 
different observers, and for the sake of comparison I have placed three of these side by 
side. I have in each case rejected the volatile matters and calculated the totals to 100, 



^0 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



Analyses of the Dust of Krakatoa which fell at different distances from Krakatoa, 





A. 


B. 


c. 






Dust which fell 


Dust which fell 




Dnfit which fell 


at points within 


nearly 900 mites 




at Krakatoa. 


100 miles from 


from 






ihe Volcano. 


the Volcano. 




Collected by Cap- 
tain Ferzeuaar. 


Buitenssorg. 


8. Barbarosea, 




Prof. C. Winkler. 


Prof. C Winkler. 


A. Schwager. 


Silica 


61-36 


66-77 


68-99 


Titanic Acid 






1-12 


0-67 


0-39 


Alamitia .... 






17-77 


16-44 


15-24 


Ferric Oxide 






4-39 


3-41 


0-<?8 


Ferrous Oxide 






1-71 


1-37 


3-72 


ManganouH Oxide . . 






0-41 


0-38 


trace. 


Lime. . 






3-45 


2-90 


2-76 


Magnesia . . 






2-32 


1-67 


0-83 


Pofcash 






2-51 


2-25 


3-47 


Soda. . 






4-98 


4-14 


4-32 



Let us now consider the causes which would affect the composition of the 
dust which fell at different points, and at varying distances from Krakatoa. 

By the influence of the great upward currents of steam, an immense mass of 
comminuted particles of pumice would be carried to the height of many miles into 
the atmosphere. Nine-tenths of this material consisted of a glass having a specific 
gravity of less than 2*3, drawn out into fine threads and thin plates, often hollow and 
containing bubbles of air, and sometimes, in all probabiUty, reduced to particles of 
ultra-microscopic dimensions. These particles of glass would tend to float by the 
adhesion between them and air, and, in the higher and rarer portions of the atmo- 
sphere, their suspension may not improbably have been aided by their mutual re- 
pulsion resulting from a highly electrified condition. 

The crystalline particles in the mass would consist of fragments of felspar, with 
a specific gravity ranging from 2*54 to 2*75, of fragments of pyroxene with densities 
of 3*3 to 3 "5, and of magnetite, with a density of 5 0. The crystals of felspar, 
hypersthene and augite were, in the original pumice, of much greater size than the 
magnetite. But the easy double cleavage in the felspars, and to a smaller extent in 
the pyroxenes, would facilitate the reduction of these minerals to finer particles than 
the magnetite. 

As the particles travelled outwards from the centre, they would tend to fall, 
therefore, in the following order: — 1. Magnetite (the hecxviest and least friable 



PROP. JUDD ON THE VOLCANIC PHENOMENA. 41 

material) ; 2. Pyroxenes (next in weight and only moderately cleavable) ; 3. Felspar 
(lighter and very cleavable) ; and 4, and last, the very light and friable glass. 

At all points, therefore, the dust which fell would have a tendency to differ in 
composition from the pumice out of which it was formed. Near the volcano the 
abundance of the crystalline materials falling, and especially of the magnetite and 
pyroxenes, would render the dust darker in colour and more basic in composition ; 
while farther away the glass- and felspar-particles which fell would have a smaller 
admixture of the more basic materials. A certain proportion of the glass, including 
the Tiltra-microscopical, the elongated, and the very thin particles, would float almost 
indefinitely, and would not find any place in the masses of dust coUected around the 
volcano. 

Besides this it must be recollected that there are always particles of both 
Clonic and inorganic dust floating in the atmosphere, and these would be carried 
down mingled with the volcanic materials. In every sample of Krakatoa-dust 
which I have examined, these ordinary constituents of the atmosphere could be 
detected. 

Further than this, the steam issuing fi-om the volcano was mingled with both 
hydrochloric and sulphurous acids, the latter taking up oxygen and passing into 
sulphuric acid. By these powerful acids the finely-divided particles of crystals and 
glass would be easily attacked, sulphates and chlorides of lime, magnesia, iron, and 
the alkalies being formed. All these substances were found in greater or less 
abundance in the specimens of dust from various localities. 

Concerning the quantity of dust thrown into the air during the Krakatoa 
eruptions, we have no data for forming any trustworthy estimate. The continuance 
for more than three months of the work of trituration among the masses of pumice, 
of so particularly brittle a character as that ejected from Krakatoa, must have 
given rise to a large quantity of tine particles which would be gradually diffused in 
the higher regions of the atmosphere. The last violent outburst, however, was of but 
short duration, and the area over which the dust-cloud spread, and the time during 
which darkness prevailed, were small as compared with the area and duration of the 
dust-cloud during the Tomboro and some other great eruptions. 

On the other hand, it may be remarked that there is i-eason for believing that 
the last paroxysmal discharges from Krakatoa were of altogether exceptional violence, 
and that water- and lava-dust may have been forcibly carried into those higher 
atmospheric strata which are characterised by extreme rarefaction and great electrical 
repulsion — strata into which, in ordinary circumstances, such particles have no chance 
of finding their way. 

What was the percentage of ultra-microscopical particles which remained in the 

atmosphere afber the larger ones had fallen it is impossible to determine^ but it waa 

not improbably very considerable. It is for physicists to determine whether such 

particles were capable of producing the wonderful optical phenomena which followed 

G 



42 PROP. JUDD ON THE VOLCANIC PHENOMENA. 

the eruption of Krakatoa, either acting by themselves, or performing the part of 
condensers of watery vapour, in the manner which Mr. Ajtken has shown such 
particles to be capable of doing. 

A question which has often been asked is : — If the optical phenomena in question 
resulted from the presence of fine particles floating in the atmosphere, might not 
these be carried down by rain and detected after they had fallen ? I am indebted to 
a very large number of correspondents, who, ever since the great eruption, have been 
sending to me specimens of dust, of materials scraped fi*om freshly fallen snow, and 
the sediments found in rain-gauges. But although the study of these was very 
interesting in itself, yet as far as aiding to establish the presence of the Exakatoa- 
dust in the atmosphere went, the results have been altogether negative. 

Nor is this result different from what might have been anticipated, as a little 
consideration will serve to show. The most characteristic substance in the Erakatoa 
dust is the rhombic pyroxene (enstatite). But this is one of the substances which, from 
its high specific gravity and its slight friability, woidd be among the first to fall. 
Moreover, this mineral occurs much more widely than was at one time supposed, 
being found very commonly in many of the andesites, which are the most widely 
diffused of all lavas, except perhaps the basalts. 

None but those who have had occasion to study the matter for themselves can 
have any idea of the quantity of mineral particles which are everywhere floating 
about in the atmosphere ; but those of local origin of course usually largely predomi- 
nate, and serve to mask the particles which have come from great distances. If the 
optical phenomena which followed the eruption of Ki*akatoa are rightly regarded as 
being due to dust in the atmosphere, they would probably result from the action of 
ultra- microscopical particles, for it is these, which, by scattering light, have the power 
of producing colour-effects. Such particles it is of course hopeless to attempt to seek 
for in the manner described. 



General CoNOiiUSiONS. 

The thoughtful consideration of some of the facts which have been detailed in the 
foregoing paragraphs is calculated, I believe, to afford an important insight into the 
nature of the forces which give rise to volcanic outbursts, and to the causes of 
the variation in character of these phenomena, in different places and at various 
times. 

All the materials ejected from the central vent of Krakatoa have been wonder- 
fully similar in their chemical and mineralogical constitution. At one period of the 
volcano's history, it is true, basaltic lavas and tuffs were thrown out from a lateral 
vent, and of these the parasitical cone of Rakata is built up ; but both before and since 
this episode in the history of Erakatoa, the materials ejected from the central crater 



PROF. JUDD ON THE VOLCANIC PHENOMENA. 



43 



have always belonged to the remarkable class of enstatite-dacite rocks. The composition 
of these rocks may be represented by the following general averages :— 



Silica (with Titanic Acid) 
Alumina . . 
Oxides of Iron . • 
Lime and Magnesia 
Potash , . 
Soda 



70 

15 
4 
5 

2 



Total 



.. 100 



In this magma apparently, by a first consolidation, well-developed crystals, equal 
to about 10 per cent, of the whole mass, seem to have been separated, these crystals 
consisting of 6 per cent, of felspar, 2 per cent, of ferriferous enstatite and augite (the 
former mineral* being twice as abundant as the latter), and 2 per cent, of magnetite. 
Making a calculation on the basis of the composition actually found by analysis for 
the whole rock, and the several minerals present, the base or ground-mass of these 
rocks would have the following composition : — 



Silica (with Titanic Acid) 


. . 72-8 


Alumina 


. . 147 


Oxides of Iron.. 


1-8 


Lime and Magnesia . . 


4-4 


Potash 


2-2 


Soda 


4-1 


Total .. 


.. lOO-O 



This magma exhibits a greater or less degree of devitrification iu different cases, 
microlites of felspar, pyroxene, and magnetite belonging to a second period of 
consolidation, separating from it sometimes in small quantities, at other times to 
such an extent as to convert the glassy base into a stony one. 

It is scarcely possible to doubt that the separation of the larger and porphyritic 

ciystals from the magma, must have taken place under totally different conditions 

from those of the second consolidation ; in all probability, when the mass existed at 

great depth and under intense pressure. And it is by no means certain that the 

proportion of glassy matrix to the included minerals has not been altered since the 

crystallization of the latter. 

02 



44 PEOP. JUDD ON THE VOLCANIC PHENOMENA. 

Now the startling fact which comes into prominence when the lavas of the 
earlier and later periods of eruptive activity at Krakatoa are studied in the field is 
that, in spite of this identity in chemical composition and of the included minerals, 
their mode of behaviour has been strikingly dissimilar. 

During the earlier period, massive lava-streams flowed firom the central vent, 
almost unaccompanied by any explosive action, and these lavas gradually accumulated 
to build up a bulky cone. In these massive lavas the slow cooling down of the 
molten rock permitted of the imperfect crystallization of the felspar, pyroxene, and 
magnetite from the base; where the cooling was somewhat rapid, magnetite and 
felspar were the chief minerals formed, as in the pitchstones; where less rapid, 
felspars and pyroxenes, as in the stony lavas. 

But during the later period a lava having precisely the same chemical composition 
exhibited perfect liquidity. Occasional lava-streams composed of this material are 
found, as at Perboewatan, but the greater portion of it, on being relieved from 
pressure by coming into the outer atmosphere, at once became distended into 
pumice, through the escape of the volatile materials imprisoned in its midst. 

Now, what is the cause of the diflFerence of behaviour of the same chemical 
compound in these two cases ? It might, at first sight, appear that the cause of 
this difference is to be sought in variations of temperature, and that the later lavas 
were more liquid because at a higher temperature, and more thoroughly fused than the 
earlier ones. 

But if we examine the porphyritic crystals of the same minerals which have 
floated about in the magma in both cases, we shall find that all the evidence points to 
exactly the opposite conclusion, namely, that the pitchstone-rock was actually at the 
higher temperature, for the crystals of felspar in the obsidian-rock are often almost 
uncorroded, while in the pitchstone they have been attacked by the fluid in which 
they floated, and have indeed been to a great extent dissolved by it. 

If we now try the actual fiisibilities of the magmas in the two cases, we shall 
find the inference derived from the condition of the felspar-crystals to be strikingly 
confirmed. In the case of the pitchstone, portions of the substance held in the flame 
of a jet urged by a strong blast are hardly affected, while in the case of the obsidian 
the material under the same conditions rapidly becomes liquid. 

But this production of liquidity in the obsidian is attended with the disengage- 
ment of a large quantity of volatile materials by which the rock rapidly passes into 
the condition of a pumice. It is, therefore, impossible to avoid connecting the presence 
of these volatile matters in the rock with the production of its liquidity. 

I have in another place * pointed out that the leucite-basalts of similar com- 
position ejected from Vesuvius at different periods exhibit just the same differences. 
When, as in the lavas of 1872, the quantity of steam and gas ^ven off from them 

• See * Geol Mag-.,' Dec. li., vol. ii. (1875), p. 68 ; also • Volcwioes,' p. 92. 



PROP. JUDD ON THE VOLCANIC PHENOMENA. 45 

was large, their liquidity was perfect; when, as in 1858, the quantity of volatile 
matter was small, the lavas exhibited the greatest viscosity. 

That by admixture with varying quantities of water many salts have their 
fusion-points proportionately reduced has long been known. Indeed, the late Dr. 
GuTHME, F.R.S., by his interesting experiments upon nitre, was able to demonstrate 
that there is actual continuity between the two states of fluidity known by the names 
of solution and fusion respectively. For, as there is a perfectly gradual rise in the 
temperature at which liquidity is produced when more and more nitre is added to a 
definite quantity of water, it becomes impossible to decide when the proportion of the 
water becomes so small that we can no longer regard the case as one of " solution," 
and we must begin to call it " fusion.''* 

That the silicates, like other salts, have their fusion-points lowered by admixture 
with water, we have many proofs. Most of the felspars are minerals of difficult 
fusibility, while the zeolites, which are analogous compounds of the silicates of 
alumina and the silicates of potash, soda, and lime, with the addition of water, are 
remarkable for their easy fiisibility and for the manner in which they swell up and 
lose their waters at a comparatively low temperature. And this is true, not only 
of definite hydrous silicates, like the zeolites; the colloids of indefinite chemical 
composition, such as tachylyte, hydrotachylyte, and palagonite, appear, to have their 
fusion-points lowered according to the proportion of water that they contain. 

In the case of the Krakatoa-lavas we have the clearest evidence that when the 
mixtures of silicates of which they consist contain water, then very fusible glasses 
are formed. In these circumstances, the earlier formed porphyritic crystals are 
but little hable to be attacked by the liquid magma in which they float. As the 
interesting synthetic researches of MM. Fougu^ and L^VY have shown that any 
particular mineral is liable to separate from a magma when the latter is kept for a 
long time at a temperature just below the point of fusion of the mineral, we can 
understand how small is the chance of devitrification taking place in magmas which 
are liquified at low temperatures, and which, by a small reduction of temperature, 
become solid. 

In other magmas, however, consisting of precisely the same admixture of sili- 
cates, but without water, we find the fusion-point far higher. The excessively heated 
magma in such cases exercises the strongest solvent action on the crystals of felspar 
immersed in it ; and in cooling down, much magnetite, augite, enstatite, and felspar 
separate out from it before it solidifies. 

I am convinced that this is a class of questions to which petrologists will have 
to give much greater attention than they have hitherto done. The characters 
assumed by an igneous rock depend not only on the peculiar admixture of silicates 
which compose it, but also on the temperature at which liquefaction and solidification 

♦ * Phil. Mag.,' vol. xviii. (1884), p. 22. 



46 PROP. JUDD ON THE VOLCANIC PHENOMENA. 

could take place in the mass; this being to a great extent dependent on the quantity 
of water that was present. The temperature at which fusion could take place would 
largely determine not only the minerals which separated out from the magma, but 
also the degree and nature of their crystallization. In other words, the texture as 
well as the mineralogical constitution of the rock would be greatly influenced by the 
proportion of water present in the magma from which it was formed. 

In the same way the actual nature of the volcanic manifestations at any 
particular vent are seen to be determined, not so much by the mineralogical 
constitution of the lava, as by the circiunstance of the quantity of water contained 
in the magma. Where this is great, the lava will be perfectly liquid, and will be 
almost wholly thrown out in the form of pumice and dust. On the other hand, lavas 
containing little water will require a very high temperature for their Aision, and they 
wlQ be characterised by great viscosity rather than perfect liquidity. 

If, as seems highly probable, the younger ejecta of Krakatoa were formed by the 
re-fusion of the older lavas, then we can trace the cause of the introduction of water 
by which their liquefaction by heat was rendered more easy. These older lavas, by 
the presence in them of hydrous compounds, and by the existence in their cavities of 
tridymite and other secondary minerals, betray the fact that they have been greatly 
acted upon by percolating waters. It is through the introduction of the sea and 
other surface-waters into rock-masses by slow percolation from above, and the 
consequent formation of new compounds, more readily acted upon by subterranean 
heat, that I am disposed to regard volcanic phenomena as being brought about. In 
this we find an explanation of the proximity of volcanoes to great bodies of water, 
which it seems to me is far more in accord with the actual phenomena than the 
supposition that water finds access to volcanic foci by means of actual open fissures. 



NoTR. — It is very greatly to be regretted that no accurate survey of Krakatoa, and of the sarronnding 
seas was made prior to the great eruption of 1883. Had such been done, a splendid opportunity would 
have been afforded us for determining whether elevation and sabsequent subsidence of the whole mass 
of the volcano actually occurred. The existing statements concerning the height of the peak of Bakata 
before and after the eruption are so confused and contradictory (see p. 23 and foot-note), while both the 
outlines and soundings on the old charts appear to be so untrustworthy, that I fail to detect certain 
evidence of any movements of the kind. As the phenomena observed at Krakatoa seem to be reconcil- 
able with principles already well established by the study of other volcanoes, I have felt it incumbent 
on me to adopt such interpretations in preference to those which depend on movements of the volcanic 
mass which are of a conjectural character. 

The theoretical questions, suggested by the study of the Kitikatoa-lavas, have been more fully 
discupsed by the author in a paper read before the Geological Section of the British Association at tlie 
meeting in Manchester in 1887. The paper is published in the ' Geological Magazine,' Dec. iii., vol. t. 
(1888), p. 1. 

J. W. JUDD. 



MR. R. H. SCOTT ON THE PUMICE. 47 

APPENDIX. 



Meteorological Officey 

116, Victoria Street, LoiidoUy S.W. 

Memorandum. 

I have examined the various statements as to the meeting of pumice in the 
Indian Ocean in the course of the years 1883 and 1884. 

With the exception of the masses of floating pumice, often bearing uprooted 
trees, &c., vehich blocked the Strait of Sunda and the adjacent harbours of Java 
and Sumatra, the great majority of entries of the substance come from the region 
reaching in latitude from the Equator to 20° S., and in longitude from 70° to 100° E. 

One observer. Captain Reeves, of the barque Umvoti, speaks of two masses — 
one between 20° and 25° S., the other between 10° and 5° S. These are separated 
by an interval of clear sea. 

Furthermore, a coasting vessel which arrived at Sydney, August 4, 1884, from 
a vQyage round Australia, reported that *' all along the north and west coasts of the 
continent vast shoals of pumice were passed through," This was probably in June 
or July, 1884. 

As the observers almost without exception found the pumice thickly coated with 
barnacles {Lepa^ ansi/era, the common southern species), the material must have been 
a long time in the water. 

We know that Krakatoa was in eruption in May, 1883, and continued more or 
less active for three months, and as pumice was met with by H.M.S. Magpie in 
6° S. and 61° E., April 22, 1884, it seems impracticable to trace the course of any 
particular deposits of this material on the sea surface. 

It is, however, interesting to learn that the precise dates of the arrival of pumice 
on the coasts of Natal, and on the Chagos Islands, were as follows : — 

Natal, September 27th and 28th, 1884. 
Diego Garcia (Chagos), October 1st, 1884. 

As Diego Garcia is in 7° S. and 73° E. (approximately), while Durban is in 
30^ S. and 31° E., it is not likely that the pumice which reached these two distant 
stations nearly simultaneously could have been ejected at the same time. 

In all discussions of the movements of the pumice it must be remembered that 
floating bodies will be much affected by the wind, and wiU not drift solely in accord- 
ance with ocean currents. 

The deposits of pumice near the coast of Australia may have drifted there before 

the north-west monsoon, which would prevail in those seas from November, 1883, to 

March, 1884. 

EOBEET H. SCOTT. 



48 



DR. MBLDRUM ON THE PUMIOE AND VOLCANIC DUST. 



A Tah\dar Statement of the Dates on which, and the Localities where, Pumice or 
Volcanic Dust was seen in the Indian Ocean in 1883-84. By Charles 
Meldrum, LL,D., F.RS. 

(Reprinted, by peionission, from the ' British Association Report/ 1885, p. 773.) 



Names of Vessels. 



Barque Actcsa (Capt. 
Walker) 



Ship Idomene (Capt. 
Johnson) 

Barqne West Auttra- 
lian (Capt. Thomas) 



S.S. Anerley (Capt. 
Strachan) 



Barque County of Flint 
(Capt. J. Rowland) 



French brig Brani 
(Capt. E. Perrot) 



Day of 
Year. 



140 

141 
141 



229 



230 



231 



239 



240 



240 



240 



Month 
and 
Day. 



1883 
May 20 

n 21 

n 21 



Aug. 11 

„ 17 

„ 18 

„ 19 

M . 27 

„ 28 

„ 28 

„ 28 



Hours. 



Position 
at Noon. 



Lat. 



2 p.m. 

to 
9 a.m. 
night 



8 a.m. to 
2 p.m. 



noon 



noon 



noon 



6 50 8. 



6 23 S. 
noon 8 35 S. 



9 41 S. 



11 08 S. 



Long. 



E. 

101 02 



88 31 
91 53 

90 28 
88 03 



North Watcher 



Anjer Roads 



8 20 S. 



4 22 S. 



92 04 



91 34 



Remarks. 



Very fine dust commenced 
to fall about 2 p.m. 
The fall continued all 
night, and stopped about 
9 a.m. on the 21st. 
Small quantities fell 
again during the night. 

Passed through large fields 
.of pumice. 

Passed a great amount of 
floating lava or pumice. 

Passed a great amount of 
lava to-day. 

Large quantities of pumice ; 
some pieces about 3 feet 
in diameter. 

Ashes began to fall at 
10.24 a.m. Showers of 
ashes and pumice lasted 
till midnight. 

Immense quantities of 
pumice and debris of 
all sorts. 

Great quantity of dust 
falling ; supposed to be 
coral dust. 

L'atmosph^re surcharge de 
sable. De minuit ^11 
heures du matin une 
tr^s grande quantity de 
sable tr^ blanc et tree 
fin a courert toutes les 
parties accessibles, m^me 
presque dans la chambre. 
Je crois que c'est le 
resultat d'un orage que 



DR. MELDRUM ON THE PUMICE AND VOLCANIC DUST. 



49 



Names of Vessels. 


Day of 
Year. 


Month 
and 
Day. 


Hours. 


Position 
at Noon. 


Remarks. 




Lat. 


Long. 








1883 






E. 




f^rench brig Brani — 
contmned. 








• 1 


O i 


nous avions observe ceg 
jours derniei*s sur Su- 
matra, pendant lequel 
le tonnerre avait des 
roulements pareils k une 
canonnade, et le sable 
enlev^ par cette tour- 
mente a ^t6 renvoy^ sap 
nous par la petite brise. 




241 


Aug. 29 


9a.in. 


5 50 S. ' 91 20 

! 
1 


II tombe continuellement 
du sable tr^ fin au 
point d*obscurcir ratmos- 
ph^re. 


Barque Catileton 
(Capt. Dior6) 


240 


„ 28 


2 a.m. 


5 58 S. 


1 93 30 


After a shower of rain the 
air became loaded with 
a fine dust, which fell 
in great quantities on 
deck. At noon dust still 
failing. At 2 p.m. dust 
still falling. 


• 


241 


,, 29 


6 a.m. 
2 p.m. 


6 66 S. 


93 01 


Collected dust off the deck. 
Pumice-stone floating in 
the water. At 2 p.m. 
dnst still falling : large 
quantities of pumice 
floating past. 


Brigantme Airlie 
(Capt. Knight) 


252 


Sept. 9 


6 a.m. 
2 p.m. 


7 31 S. 


103 11 


Large quantities of lava. 
Passing through large 
quantities of lava. 


French barqne Qipsy 
(Capt. Martin) 


252 


9 


9 a.m. 


4 57 S. 


82 06 


Grand banc flottant de 
pierre-poDce pendant 
toute la journee, suivant 
le Tent comme dans la 
mer de Sargosse. 


Frencli barque Marie 
Alfred (Capt. Br6. 
geon) 


263 


,. 20 


6 a.m. 


7 02 S. 


101 15 


Noas passons dans des 
bancs succcssifs et tr^s 
rapproch^s de pierre- 
ponce. 


Barqne Hottenhura 
(Capt. Chichester) 


286 


Oct. IS 


4 p.m. 


Snnda 


Strait 


Tremendous fields of pum- 
ice stopped the yessel. 




287 


„ 14 


4 a.m. 


No 


obs. 


Lots of pumice alongside. 




288 


„ 15 


midt. 


7 19 S. 


104 00 


Passing large fields of 
pumice. 



50 



DR. MELDRUM ON THE PUMICE AND VOLCANIC DUST. 



Namea of Yesgels. 



Day of 
Year. 



Month 
and 
Day. 



Honrs. 



Position 
at Noon. 



Lat. 



Long. 



Bemarlca. 



S.S. Oaronne 



LS. Countess of Errol 
(Capt. Taylor) 



Barqne Bollo (Capt. 
CuiTie) 



Barqne lEva Joshua 
(Capt. Florentin) 



Fiencli barqne Hen- 
riette (Capt. A. de 
Lavit) 



Barqne Ta Lee (Capt. 
Stolzee) 



294 



299 



300 



319 



320 

321 
332 

336 



337 

338 

339 



341 



1883 




Oct. 


21 


916 
a.m. 


»» 


26 


noon 


n 


27 


8a.ni. 


Nov. 


16 


6 a.m. 


»1 


16 


noon 


»» 


17 


noon 


)> 


28 


8 a.m. 


Dec- 


2 


6 a.m. 


»f 


3 


6 a.m. 


)> 


4 


6 a.m. 


9> 


5 


9 a.m. 


»» 


2 


4 p.m. 


)9 


7 


a.m. 



l5 15 s. 



E. 

o / 

78 07 



7 01 S. 

8 44S. 
6 19 S. 

8 04 S. 

9 36 S. 
6 24 S. 

6 42 S. 



104 49 
102 40 

88 66 

87 26 

86 46 
64 46 

89 07 



No 

7 14 S. 

8 44S. 
6 07 S. 

8 69 S. 



oba. 



87 32 

? 

81 66 

82 14 



Passed throngh aeyend 
fields of pnmice-stone of 
varions sizes. Some 
pieces that were picked 
np had barnacles nearly 
one inch long adhering 
to them. 

Vast qnantities of pnmice 
all ronnd the ship. 

Sailing throngh vast qnan- 
tities of pnmice. 

Since daylight sailing 
throngh large qnantities 
of pnmice. At midnight 
still lai^e qnantities of 
pum ice floating on water. 

Still large qnantities of 
pnmice floating past. 



Sailing all day throngh 
floating pnmice covered 
with barnacles. 

An jonr nons avons re- 
marqn^ qne noas ^Uona 
environues de pterre- 
ponce. A 9 henres nons 
sommes tonjonrs enton- 
r^s de pieire-pouoe. 

II y a encore de pierre-ponce. 

Nons avons encore ren- 
contre de pierre-ponce. 

Nons recontrons encore 
beanconp de pierre- 
ponce. 

Passed a bank of pnmloe 
extending abont twenty- 
five miles ; some pieces 
abont two feet square. 

Still passing p amice-stone 
and a kind of ashes. 



DR. MBLDRUM ON THE PUMICE AND VOLCANIC DUST. 



51 



Names of Vessels. 



Day 

of 

Year. 



Month 
and 
Day. 



Hours. 



Position at 
Noon. 



Lat 



Long. 



Remarks. 



8hip Shah Jehan 
(Capt. Williams) 



Ship Ifwereauld (Capt. 
Leslie) 



Barque Evelyn (Capt. 
Stevenson) 



Barque May Queen 
(Capt. Hngon) 



Sch. Lord Tredegar 
(Capt. Clarke) 



343 



84.7 



348 



349 



346 



348 



349 



354 



355 



362 



8 
9 

10 



1883 
Deo. 9 



6 a.m. 



18 



14 



15 



12 



14 



15 



20 



21 



28 



1884 
Jan. 5 



8 
9 

10 



8 a.m. 



10 a.m. 



noon 



2 p.m. 



noon 



noon 



^ 26 S. 



13 47 s: 



15 03 & 



15 80 S. 



11 45 S. 



9 54 8. 



a.m. 7 56 i 



9 40 S. 
7 30 S. 
2 14 N. 

6 35 S. 

12 12 S. 
14 56 S. 

17 34 S. 



E. 



M 58 



82 00 

81 42 

80 51 

87 09 

87 56 
89 32 

88 11 
88 26 
85 35 

68 25 

66 59 
65 18 

63 04- 



Noticed the sea ooyered 
in streaks with what 
appeared to be pnmice- 
stone in pieces and iu 
powder ; lowered the 
boat and picked up some ; 
some of the stones 
covered with barnacles. 

Throughout the day the 
sea covered in streaks 
with some kind of lava 
and ]arg8-sized lumps of 
pumice-stone. 

Passed a great deal of 
pumice and lava this 
day. 

Passed a lot of pumice and 
lava. 

Passed through a quantity 
of dnst seemingly floating 
on the surface. 

Passed through a quantify 
of pumice-stone. 

Passed large quantities of 
pumice-stone. 

Passing great quantities of 
pumice. 

Still passing quantities of 
pumice. 

Une infinite de parcelles 
de roche brdlee sur Teau. 



Passed throngh a quantity 
of lava. 



Passed throngh a great 
quantity of pnmice to- 
day. 



H 2 



52 



DR. MELDRUM ON THE PUMICE AND VOLCANIC DUST. 



Names of Vessels. 


Tear. 


Month 
and 
Day. 


Hoars. 


Position at 
Noon. 


Bemarka. 




Lat. 


Long. 








1884 






E. 




French barque Besolu 
(Capt. Monton) 


8 


Jan. 


8 


p.m. 


? 06 S. 


.MOi 


Trayers^ plosienrs bancs 
de pieire-ponce. 


Barqae May Queen 
(Capt. Hagon) 


9 


Y> 


9 


a.m. 


7 COS. 


83 13 


Une infinite de roche br6l^ 
flottant. 




12 


»> 


12 


p.m. 


11 23 S. 


75 46 


Une infinite de debris voU 
caniques. 


Ship Argomene' (C9,pt. 
H. Williams) 


12 


»9 


12 


8 p.m. 


7 51 S. 


87 06 


Fusing through large 
quantities of pumice. 


Ship Boderick DM 
(Capt. Boldchild) 


13 


11 


13 


4 p.m. 


13 34 S. 


90 j;0 


Passing through large 
quantities of pumice. 




14 


»» 


14 


p.m. 


9 25 S. 


90 26 


>i « » 


French barqae Eugenie 
(Capt. A. Amaad) 


15 


»> 


15 


p.m. 


6 14 S. 


81 40 


Beaucoup de pierre-ponce 
formant de lis allong6 a 
Touest. 


Barqne Star of Greece 
(Capt. W. Legg) 


21 


»> 


21 


7 a.m. 


18 49 S. 


85 45 


Tjarge quantities of pumice 
in separate streams from 
S.E. toN.W. At 6 p.m. 
still passing large quan* 
tities of pumice. 




22 


i» 


22 


2 a.m. 


13 21 S. 


86 06 


The streams of pumice- 
stone stopped* 




23 


n 


23 


midt. 


10 45 S. 


86 60 


A large stream of pumice- 
stone. 


Barque Eva Joshua 
(Capt. Florentin) 


22 


>» 


22 


p.m. 


13 05 S. 


66 40 


Sighted pumice-stone. 


Sch. aienesk (Capt. 
Feleng) 


26 


»f 


26 


a.m. 


3 19 S. 


81 05 


Benoontr^ & chaque instant 
des bancs form6s par 
des pierres-ponoe. 


Sch. Mary Whitridge 
(Capt. Howfts) 


40 


Feb. 


9 


7 a.m. 


9 41 S. 


88 26 


Passing lots of floating* 
pumice-stone. 




41 


>1 


10 


5 a.m. 


8 lis. 


89 24 


n )> 9* 




42 


»> 


11 


5 a.m. 


5 06S. 


90 11 


» »> »J 




43 


>» 


12 


2 a.m. 


2 43S. 


91 26 


Passing large fields of 
pumice. 



DR. MELDBUM ON THE PUMICE AND VOLCANIC DUST. 



53 



Names, of Vessels. 


Day 

of 

Tear. 


Month 
and 
Day. 


Honrs. 


Position at 
Noon, 


Reouirks. 




Lat. 


Long. 








1884 






B. 




Barqne County of Flint 
(Capt. J. Rowland) 


57 


Feb. 26 


— 


i 27 S. 


86 63 


Great quantities of pumice, 
which appears to have 
been long in the water. 




58 


„ 27 


— 


1 SOS. 


87 48 


Pumice-stone passing. 




61 


March 1 


4 a.m. 


2 21 S. 


86 21 


Great quantities of pumice- 
stone in sight. 




62 


2 


2 a.m. 


2 40 S. 


84 31 


Great quantities of pumice 
passing. 




63 


„ 3 1 2 p.m. 

1 


2 36 S. 


84 10 


» »> »> 




65 


„ 5 3 a.m. 


4 01 S. 


83 57 


» »> >» 


} 






2 p.m. 


— 


— 


)' »» jt 


Ship FaHhenope (Capt. 
F.Gray) 


64 


4 


— 


1 36 S. 


87 21 


Sea strewed with pumice* 
stone covered with 
barnacles. 




65 


5 


— 


2 14 S. 


87 21 


>i >» » 


. 


66 


6 


— 


3 36 S. 


88 04 


9J 7) >f 




70 


„ 10 


— 


5 52 S. 


88 16 


>> >9 )f 




72 


,, 12 


— 


10 38 S. 


86 09 


Sea covered with lava and 
pumice 2 feet thick. 




75 


„ 15 


— 


17 49 S. 


70 40 


Sea strewed with lava and 
pumice. 


Ship Kelvinside (Capt. 


69 


9 


noon 


14 40 S. 


81 56 


Since 7th been sailing 
through floating pumice 
in pieces from the size 
of a cocoanut to pieces 
almost like dust. 


Barque Excelsior 
(Capt F. Fidgar) 


72 


„ 12 


6 p.m. 


20 27 S. 


78 09 


Great quantities of floating 
pumice. 


Sch. Iris (Capt. Shaw) 


82 


M 22 


p.m. 


9 35 S. 


76 39 


Passing vast quantities of 
pumice. 




85 


„ 25 


a.m. 


16 33 S. 


72 11 


>» 5» « 


Sch. Northern Bell 
(Capt. L. Moiris) 


84 


,, 24 


p.m. 


26 33 S. 


70 00 


For four hours passing a 
vast quantity of pumice- 
stone covered with 
barnacles. 



54 



DR. MELDEUM ON THE PUMICE AND VOLCANIC DUST. 



Namefrof Vessels. 


Tear. 


Month 
and 
Day. 


Hours. 


1 
Position at 
Noon. ( 

1 


RemarkB. 




Lat. 


Long. 








1884 






B. 




Ship Inverccmld (Gapi. 
Leslie) 


93 


April 


2 


a.n]. 


(K> 06 S. 


*3b 


Passing through aquantilTf 
of pumioe. 




97 


)i 


6 




4 40S. 


91 13 


During last five days passed 
through a quantity of 
pumice - stone, of a 
greenish colour and 
covered with barnacles 
and crabs. 


Barqne Evelyn (Capt. 
Stevenson) 


102 


)> 


11 


a.m. 


2 10 S. 


90 13 


Passing quantities of 
pnmioe-stone. 


Barque Peggie Boy 
(Capt. Hill) 


106 


i» 


15 


a.m. 


11 34 S. 


69 02 


Passed large quantities of 
pumice. 




112 


11 


21 


a.m. 


16 65 S. 


68 22 


Passed quantities of 
pumice. 


S.8. Madagasear (Capt. 
A. Vielle) 


120 


)i 


29 


p.m. 


18 22 S. 


67 16 


Several pieces of pumice 
floating alongside. 


Ship Knight Com- 
mander (Capt. BeU) 


120 


11 


29 


a.m. 


16 38 S. 


72 19 


Passed through fields 
of pumice-stone and 
scori». 


Barque Caller Ou 
(Capt. Rae) 


125 


May 


4 


a.m. 


11 07 S. 


62 41 


Sailing through quantities 
of lava. 


Lug^r Success (Capt. 
Hazel) 


125 


»» 


4 




10 16 S. 


62 35 


Depuis plusieurs jours la 
mer est couverte de 
pierre et de sable vol- 
canique d*une couleur 
jaun&tre. 


Ship Knight Com- 
panion (Capt. Davis) 


136 


»t 


15 


a.m. 


10 32 S. 


88 53 


Passing through quantities 
of pumice. 


Barque Tris (Capt. 
Evans) 


145 


»» 


24 


p.m. 


5 21 S. 


94 44 


A great quantity of floating 
pumice. 


French barque Louise 
Collet (Capt. Beck- 
man) 


152 


>» 


31 


a.m. 


12 43 S. 


81 29 


On rencontre tonjours des 
pierres-pouce. 


Brig Flora (Capt. 
Menton) 


152 


1> 


31 


p.m. 


10 18 S. 


68 09 


Le capitaine tombe a la mer 
en p^chant des pierres- 
ponce. 


•Ship Broomhall (Capt. 
Grieve) 


165 


June 


13 


2 p.m. 


5 29 S. 


89 39 


Passing through quantities 
of pumice covered with 
barnacles. 



DR. MELDRUM ON THE PUMICE AND VOLCANIC DUST. 



55 



Names of Yessels. 



Drj 

of 

Year. 



MoDtH 
and 
Day. 



Hours. 



Position at 
Noon. 



Lat. 



Long. 



Remarks. 



Brig Bio Loge (Capt. 
Ix>yett) 



Sch. Iris (Capt. Shaw) 



Ship Beigate (Capt. 
Ritchie) 



Barque Northern Btaa- 
(Capt. Evans) 



Barqae Ciiy of Tetnjore 
(Capt. Sinclair) 



169 

169 
175 
175 
176 
177 
183 

190 

207 
208 



Sch. Catherine Marie 210 
(Capt. Stabingtou) 



222 
223 

224 

225 

226 
227 



1884 ' 
Jane 17 noon 



17 
23 
23 
24 
25 



July 



25 



Aug. 9 
„ 10 

11 

„ 12 

13 
14 



4 p.m. 
6 a.m. 

6 p.m. 

5 p.m. 

6 p.m. 
2 a.m. 

7 a.m. 

4 a.m. 
4 a.m. 

7 a.m. 



4 p.m. 
noon 

5 a.m. 

8 a.m. 

4 p.m. 
4 p.m. 



11 29 S. 



14 39 S. 

15 16 S. 

16 07 S. 

17 08 S. 

4 25 S. 

13 42 S. 

14 46 S. 
23 36 S. 



E. 



126 29 



113 36 

110 08 
106 51 

114 33 

93 47 

113 42 

109 43 

59 40 



Passed large quantities of 
pumice. 



14 45 S. 



Ill 20 



15 28 S 1 108 12 



16 05 S. 

16 00 S. 

16 04 S. 
16 06 S. 



104 53 

101 56 

99 05 
96 16 



Passing vast quantities of 
pumice. 



Passed throngh large quan- 
tities of pumice. 



liarge quantities of pumice 
floating on the water. 



Passed through quantities 
of pnmice varying in size 
from an orange to a 
walnut shell. Picked 
up some pieces covered 
with barnacles and lim- 
pets. 

Passed small pieces of 
pumice. 

Sailing through large quan- 
tities of pnmice floating 
in streaks like Gulf- 
weed. 

Still sailing through quan- 
tities of pumice. 

Still sailing through 
pnmice. 



»» >> « 

Less pumice to-day. 



56 



DR. MELDRUM ON THE PUMICE AND VOLCANIC DUST. 



Narne^ of Vessels. 



Day 

of 

Year. 



Montli 
and 
Day. 



Hours. 



Position at 
Noon. 



Remarks. 



Lat. 



Long. 



Sch. Jdsper (Capt. 
Stannard) 



Barque Marion Neil 
(Capt. Patereon) 



Barque Jane Maria 
(Capt. Griffiths) 



Sch. Coleridge (Capt. 
Marshall) 



Barque Caller Ou 
(Capt. Rae) 

S.S. Castlehank (Capt. 
Chevalier) 



Barque Jane Maria 
(Capt. Griffiths) 



French barque France 
CJufrie (Capt. 

Lavary) 



228 

230 
239 

240 
243 
245 

261 
262 

263 
271 

272 

284 

287 

288 
288 

290 

316 



1884 
Aug. It5 

„ 17 
26 

» 27 

„ 30 

Sept. 1 

„ 17 
18 



» 19 

» 27 

„ 28 

Oct. 10 
„ 13 

14 
14 

i«; 

Nov. 11 



a.m. 

a.in. 
8, a.m. 

6 a.in. 

8 a.m. 

7.30 

a.m. to 

noon 

noon 
4 p.m 



noon 
8 a.m. 

3 p.m. 



p.m. 

3.30 
p.m. 

5 a.m. 

5 p.m. 



23 06 S. 

20 56 S. 
14 09 S. 

14 36 S. 

15 19 S. 
9 ION. 

21 16 S. 
20 39 S. 

20 04 S. 

7 20 S. 

8 39 S. 

6 58 S. 
10 44 S. 
12 .33 S. 



15 09 S. 



20 21 S. 



E. 

O § 

61 47 

61 01 
108 06 

106 39 
100 30 
112 11 

50 20 

51 10 

52 24 
93 02 

68 31 

102 54 
93 57 
90 19 



109 59 



58 55 



Passed several pieces of 
floating pa mice. 



A lot of pumice-stone 
floating past. 



Passed through a quantity 
of very small pumice- 
stone. 

Several pieces of floating 
pamice. 

Passed large quantities of 
pumice which, apparent- 
ly, had been a long time 
in the water. 



Much lava floating about. 



Passed through large quan- 
tities of pumice, which 
seems to have been a 
long time in the water. 

Passed a large quantity of 
floating pumice. 

Passed a large quantity of 
very small pumice. 



Large and small pieces of 
pumice seen frequently 
during the afternoon. 

Depuis plasieurs jours la 
mer est couverte de 
pierre-ponce. 

J'ai parcouru environ une 
^tendue de 1,200 milles 
par latitude sud ou j'ai 
rencontr^ beauoonp de 
pierre-ponce. 



PLATE IL 

Fig. 1. — This drawinf^ is reproduced from one in Yebbbek's 'Atlas/ which was 
taken in October, 1883. It shows the slopes of the portion of the peak 
of Rakata which remained standing after the great outburst, covered 
with enormous masses of pumice and dust. In this covering, streams 
have already cut out a series of anastomosing channels, while the action 
of the sea has given rise to the formation of a cliff. 

Fig. 2. — This is based in part on the beautiful coloured drawing in Yerbeek's 
'Atlas,' also made in October, 1883, and in part on the photograph 
subsequently obtained (June, 1886), when some details before invisible 
were rendered apparent by the washing of the surface by rain* It 
must be remembered that the surface looked at is not a vertical plane 
lying in one azimuth, but consists of two planes meeting in the central 
line at an angle of about 135^, and inclining from the vertical by about 
30°. The lowest, nearly horizontal, beds belong to the oldest ejections of 
the volcano, andesite with tridymite. The lava-currents, tuff beds, and 
dykes of the mass of the volcano are composed of different varieties of 
basalt. A study of these shows that lateral eruptions must have taken 
place on the flanks of the cone, and that, as in the case of Etna, there 
must have been a shifting in the axis of the cone. The central dyke 
seems to indicate that the last eruption from this cone must have con- 
sisted of an andesitic material. 

For the skiMul drawing of this Plate, and of Plate III., I am indebted to 
Mr. A. E. TuTTON. 



Krakaioa, Rep. Boy. Soc, Com. 



PLATE II. 



rMiS^- ttff1f| 




Ttpo-Etobiik> Co., Scolpt. 



PLATE III. 

Sections of the Lavas of Krakatoa. 

Fig. 1. — Section of the older andesite of Krakatoa, as seen when magnified 25 
diameters. A portion of the slide has been chosen where the crystals of 
felspar, enstatite, augite, and magnetite are more crowded together than 
is usually the case. The reddish tint of the base when seen by reflected 
light is due to the incipient decomposition of magnetite grains and the 
formation of the hydrated ferric oxides. 

Fig. 2. — Portion of the base of the same rock, as seen when magnified 250 diameters. 
Microlites of felspar, tridymite (?), and magnetite abound, and with some 
of pyroxene and hornblende (?), make up a stony base. Cavities lined 
with tridymite, quartz, and hornblende are seen in this base. 

Fig. 3. — Zoned and much corroded crystal of felspar, magnified 35 diameters, from 
the porphyritic pitch stone of Krakatoa. Such crystals, in xyhich the 
glass inclusions are in great part, if not entirely, of secondary origin, 
abound in this i-ock. In some cases, as shown by the figure, their con- 
tinuity with the enveloping glass is clearly apparent 

Fig. 4. — Glassy base of the porphyritic pitchstone magnified 250 diameters. The 
abundant separation of granules of magnetite all through the glass 
which envelopes the microlites of felspar and magnetite is very well seen 
in this section. 

Fig. 5. — Section of the porphyritic obsidian of Krakatoa, as seen magnified 25 
diameters. The pale brown glass, with a few scattered microlites, has in 
its midst a group of crystals, felspar, enstatite, augite, and magnetite, 
with some of the darker-coloured and less fusible glass still adhering to 
them. 

Fig. 6. — Portion of the base of the same rock as the last, as seen magnified 250 
diameters. The sparsity of the microlites of felspar, pjnroxene, and 
magnetite in the very glassy base is well illustrated by this section. 



Krakcuboo: Rep. Roy. Soc. Com. 



Mate 3. 




P T uif. H«,dal. I'ax-kM- ^ Oow«rdi, lath. 



Sections of the Rocks of Krakatoa. 



PLATE IV. 

The Pxtmice Ain> Dust of Ebakatoa. 

Fig. 1. — Section of pumioe thrown out during the earlier portion of the Erakatoa 
eruption (May, 1883), cut in the direction of the drawn-out fibres of the 
mass. This pumice was much finer in grain than the bulk of the Krakatoa 
pumice, and contained no porphyritic crystals. It is represented as seen 
with a magnifying power of 50 diametera 

Fig. 2. — Cross section of the same pumice, magnified 50 diameters. 

Fig. 3. — Section of common pumice of Erakatoa, as seen with a magnifying power 
of 50 diameters. In. the midst is seen a group of crystals of felspar, 
eustatite, and magnetite. In this pumice the structure is much coarser 
than in that represented in Figs. 1 and 2, and large irregular air-cavities 
abound in it. 

Fig. 4. — Section of artificial pumice, as seen magnified 50 diameters, made by fusing 
the porphyritic obsidian of Erakatoa. The escaping gases distend the 
mass, producing a pumice quite similar in appearance to the common 
pumice of Erakatoa. A porphyritic crystal of felspar is seen near the 
middle of the slide. 

Fig. 5. — Pumice-dust, which fell on board the Arabella when about 1,100 
English miles distant firom the volcano. The forms of the particles of 
pumice are well seen. In this dust, which fell at a great distance 
from the volcano, fragments of the crystallised minerals become few and 
inconspicuous. The particles are shown as seen with a magnifying 
power of 250 diameters. 

Fig. 6. — Similar material, formed by triturating the common Erakatoa pumice in a 
mortar, as seen with magnifying power of 250 diametera 



KrakatocL. Rep . Roy. Soc. Cotrv. 



FUUe^f. 




^"arkBrScCarmr^ dd stlitli 



¥fc«t.Nvmn«yi&Ca imp. 



Fumice and DiiBt of KraLkatost. 



"•'J' 



^(^'.c S, 



Y 


-H-T-r- 




s 


0* , ' 


> 


o.tv^ iF 


i^ t 




-3 


J- 


\ 


.1 


- 




— 1^ 


r^ 








• « 




^-H^' h: . 


>A si 


J 












of 








•• 


•• • 






^Jl 


>w^ 




^ 










CO 


t -^ 


i ^ 




4- 


^ 


1 


12 / W- ■ 


- -f^^ 


V^ 






j 










* 
^ 


2^ a- 


W^ 


"T 


r 






n 


PJ.JtL . 


— fi 








— H 








V 


5} 




r^^^ 


^ 








^:' 


m^^ZmIi 


















£ 




UJ *> 

JO 


^^^ . 








..,.^_. 


r .<* j£( p 






















30) 




.^ 


is- 




.r-i^TiSL. . 






















3 

ZJ 


/•• 




T 


r^.^-^lt 4 
























^ 


Lr^> 


^^ ^ _. 


















fi 




3< ^ 




p^>> 


J/ 


>?^ 


^" ^ 


i 
















f 






^^ 


ji 


A 


T ^i 


1 




















u ^ 


^*n^ 


j| 


li 


n 


''/ 


?i^ 
























J^ 


^ 


*^ -ii 


* " 


^ 


-i ^ - 














r 








"o 8^ 




4 










_ ^itSl. 






















^ 

:> ^ 


r . 


\ 




i 






.r4 ! 






















r^ r 


t 


^ 








a 


^^id3 






















au. ^ 


^ 










? 


1 ' ' 






















*p 


t 


T 


'h 






'^1 . 


-14* 




















0^ 3 


D'k 




J 


-a-jj 




















9flQ • 

^ Z 


*!i 


il 


S 


1 


X 


r- 1- t- 












{ 






1 




fui 


1^ 


sj 




Hi 












rr 










> 

1 5 


Jh 


n 


r^ 


1 


\ 




!^' 












, 










)W ' J» 


'i'-Tf*r!M 


,*• 


«3i 


i^ 


-su 


;S5» 


•cs'o d'i;n' 






















'lU bi'^ 


tl l1 




k 






H 




















V 




'< ""^ 


Z*^ 










I! 


^ -it 






















;Q P^ 














— -if- 


1 
















•" 




;tiJ 

X 














M 


f t 
















1 




If- 1 — 














*- -^:::ia 


1 
















I 




^0 b 














'^ < / 


•1 i 
















V 




►CO • fi 


^_ 1 














-^t 
















1 




z 


\J 


1 










-iiL^ -- 


r 
















» 




z 


^ 


I 


k* 










- -f- ^ 
















' i 







(_ 


V 










si--^- 


i lj-3 H 


















\ 


^ s 


M 






^ 






3 r^M 


















^ 


» 


w 1 


. i\ ' 


^ 




t i ^ ^ 


§^^^o^^^ 1 


















1 


z 


\ \\ 


'^ 


t ^B 


*^iV *^4ti J'^'a 




















; 


^^ 


t ^ ^ 


Y"\ 1 "^"^^ 


V 


















< 


\^|:i_i_-i_l 


•i • . <p^ 




















> 

^ b 

(0 x^ 


^trtd 


JlL J 1.1 
















V 


2 




NjJ -1 ^ 


















• 


o r 


^ f f 






















\mi 




















o 


^ ^ 




i J 
















u 

< o 




w 












1 


i^ 


3 ^ 

0. 




rs 


s- Ji- 








i 


'^ 


u 


\ 


\i 










1 


z 


11 

4^ < • 










1 


1 


y^ 


} 








•1^ 


2 \ 


X 


w 










3 ,j 


00 S 

00 




-^v 


IL 










^ 


t « 


/ 


^ 




m 












UJ 




>fiM^ 






< 


1l 










1 


Q 

o 


<# 


ir^n 


i-v. <rt r 


















1 


d . 


^ /^i 


t t ^ 






















•d 


i"'-'^ 

^tj 


""^t^ 1 




















-0' 


^ 
s 


1 


•z3 w 




















'^ 


o 






4 


4 5 


















i 




{" 




— es-^ 1 




















1 


e. 


* 




■ \ 


i_ 


\- 




i -J! 


1 




in 








— 




ji 



PART n. 



ON THE AIR WAVES AND SOUNDS CAUSED BY THE ERUPTION 

OF KRAKATOA IN AUGUST, 1883. 

Prepared in the Meteorological Office, 

AND 

Presented by lAeut-General K. Strachey, F.R.S., Chainnan of the Meteorological 

CounciL 



Section L— AIR WAVES. 



Notes on this subject were presented to the Royal Society in December, 1883,* but 
since that date observations made at many other places, besides those first discussed^ 
have been obtained, and the available records may now be regarded as complete. 

At the desire of the Committee appointed by the Boyal Society to collect 
information relating to the eruption of Erakatoa, which occurred in August, 1883, 
the present report has been drawn up in the Meteorological OflGlce, under the general 
supervision of the Chairman of the Meteorological Council, the details having been 
worked out by Mr. R. H. Curtis, one of the senior clerks in the Meteorological 
Office, Mr. C. Thompson assisting him in the preparation of the accompanying 
curves and diagrams. 

The stations from which barometrical or other registers supplying evidence 
of the disturbance, have been received, with the nature of the register and of 
the recording instrument, the general character of the data, and the period over 
which the observations extend, .in each case, are shown in the annexed Table I. 

* ^* Kote on a Series of Barometrical DiBturbanceB which passed over Europe between the 27th and 
3l8t of August, 1883,'* by Bobt. H. Scott, F.K.S., Secretary to the Meteorological Council; and ''Note 
on the Forgoing Paper,'* by Lieutenant-General Strachey, F.K.S. Printed io the 'Proceedings of the 
Royal Society,' No. 229, vol. xxrvi., pp. 139-16]. 

I 



LTEUT.-GENERAL STRAOHET ON THE AIR WAVES. 



TABLE I. 

Stations from which barometrical or other observations have been received, with a 
description of the recording instrunients and data. 



Station. 



Batayia 
Batavia 
Manila 
Melbourne 

Sydney 
Dunedin 



Wellington, 

N.Z. 



South Georgia 

Loanda 

Mauritius 

Bombay 

Calcutta 



Data received, and nature of 
recording instrument. 



Continuous automatic record 
of gasometer indicator. 

Hourly observations of baro- 
meter and thermometer. 

Hourly observations of pres- 
sure, temperature, wind, ^. 

Photographic copy of record 
from a **Kew pattern "photo- 
barograph, and also tracing 
of record of a ** King " baro- 
graph. 

Tracing of record obtained 
from an electrical baro- 
graph (two copies). 

Tracing of a "Richard" 
barograph record. 



Tracing of a "Richard" 
barograph record. 



Tracing of a "Sprung" 
barograph record. 

Tracing of a "Richard" 
barograph record. 

Photographic copy of record 
obtained from a "Kew 
pattern " photo-barograph. 

Photographic copy of record 
obtained from a "Kew 
pattern " photo-barograph. 

Tracing of record from a 
" Kew pattern " photo- 
barog^ph; also zinco- 
graphed copy of curve. 



General character of data. 



Open scale and clear record . 



Time, scale, dbc., very open, 
and copies carefully made. 



Very open scale, showing 
clearly some small move- 
ments; trace carefully made. 

Scale not very open, and 
tracing rather roughly 
made. 

Scale not very open, and 
tracing rather roughly 
made. 

Time scale leather contracted ; 
tracing carefully made. 

Scale small, but oopy care- 
fully made. 

Time scale, ^., sufficiently 
open, and copy very good. 



Time scale, &c., good, and 
copy very good. 



Time scale, &c,, good ; trac- 
ing carefully made. 



Duration of Record — 
Greenwich Civil Time. 



From 



To 



2 p.m., 
26th Aug. 

1 a.m., 
21st Aug. 

1 a.m., 
20th Aug. 

10 a.m., 
25th Aug. 



a.m., 
24th Aug. 



9 a.m., 
27th Aug. 



NOOD, 

27th Aug. 



9 a.m., 
26th Aug. 

10 a.m., 
27th Aug. 

Noon, 
26th Aug. 



10 a.m., 
26th Aug. 



10 a.m., 
26th Aug. 



Noon, 

28th Aug. 

Midnight, 
81st Aug. 

Midnight, 
10th Sept. 

10 a.m., 
30th Aug. 



9 a.m., 

Slst Aug. 



a.m., 
3rd Sept. 



10 a.m., 

3rd Sept. 



7 a.m., 

2nd Sept. 

10 a.m., 

3rd Sept. 

7 a.m., 

1st Sept. 



10 a.m., 

1st Sept.- 



8 a.m., 

1st S^t. 



LIEUT.-GBNERAL BTRACHBY ON THE AIE WAVES. 
Table I. — continued. 



59 



Station. 



Zi-Ka-Wei ., 
(Shanghai.) 



Tokio. . 
Tiflis . • 
PawlowBk . . 

St. Petersburg, 

Cracow 

Buda-Pesth . . 
Vienna 
Berlin 
Leipeic 

Magdebnrg • . 

Munich 

Milan. • 
Modena 



Data received, and natare of 
recording instrament. 



Tracing of record from a 
" Kew pattern " photo- 
barogitiph for 1st and 2nd 
oscillations, and also of re- 
cord from a " Secchi " 
balance barograph for Ist 
to 3rd oscillations. 

Tracing of record from a 
"King" barograph. 

Honrlj readings of the baro- 
meter. 

Tracing of the curve from 
a " E^ler " barogragh. 



Tracing of the curve from a 
'* Hasler " barograph. 



Lithographed copy of trace 
from a " Kreil " barograph. 



Lithographed copy of baro- 
gram. 

Original barograms from a 
"Kreil "barograph. 

Copy of barograms . . 



Copy of barograms . 



Lithographed copy of a 
" Sprung " barograph re- 
cord. 

Lithographed copy of a 
"Richard" barograph re- 
cord. 

Hourly readings of baro- 
meter and wind. 

Lithographed enlarged copies 
of barometer curves. 



General character of data. 



Scale of " Secchi " instru- 
ment very open, except for 
time, which is contracted ; 
scale of photo curve good ; 
tracings carefully made. 



Very open scale, and tracing 
very carefully made. 



Trace not continuous, instru- 
ment registers only at 10 
min. intervals ; carefully 
traced. 

Trace not continuous, scale 
open, and tracing ap- 
parently carefully made. 

Scale not very open ; trace 
shows scarcely any signs of 
distarbance. 

Scales open, and oscillations 
clearly shown. 

Record at 5 min. intervals ; 
scales fairly open. 

Record at 15 min. intervals ; 
time scale rather contracted. 

Very open scales 



Good, but time scale rather 
contracted. 



Good record, but time scale 
very contracted. 



Curves have been very much 
enlarged from the originals, 
and have very open scales. 



Duration of Record — 
Greenwich Civil Time. 



From 



To 



2 a.m., 
22nd Aug. 



9 a.m., 
27th Aug. 

1 a.m., 
26th Aug. 

Midnight, 
26th Aug. 



6 p.m., 
26th Aug. 



Noon, 
27th Aug. 



Midnight, 
26th Aug. 

Noon, 
27th Aug. 

Noon, 
26th Aug. 

11 a.m., 
27th Aug. 

Midnight, 
26th Aug. 



Midnight, 
26th Aug. 



Noon, 
25th Aug. 

Noon, 
26th Aug. 



6 p.m., 

29th Aug. 



9 a.m., 

2nd Sept. 

Midnight, 
2nd Sept. 

Midnight, 
30th Aug. 



Midnight, 
30th Aug. 



Noon, 

1st Sept. 

Midnight, 
30th Aug. 

Noon, 

29th Aug. 

Noon, 

5th Sept. 

5 p.m., 

3l8t Aug. 

Midnight, 
1st Sept. 



3 a.m., 

31st Aug. 



11 a.m., 

1st Sept. 

Noon, 

3rd Sept 



60 



LIEDT.-GENERAL STRACHBT ON THE AIR WAVES. 
Table I. — continued. 



Station. 



Rome. • • 
Palermo 
San Fernando . 

Lisbon 



Serra da Es- 
trella. 

Coimbra 

Paris — 
ParoSt.Manr 



Montsonris. . 

Brussels 
Greenwich • • 

Eew • • • • 

Oeldeston 
Oxford 
Falmontb 
Valencia 
Armagh •• 



Data receiredy and natnre of 
recording instrument. 



Tracing of a "Richard" 
barograph record. 

Tracing of a " Secohi " baro- 
graph curve* 



Photographic copy of record 
irograph 
Salleron, of Paris, 



from barograph made by 



Tracing of a "Redier" baro- 
gram. 

Tracing of a "Richard" 
barograph record. 

Original curve of a "Kew 
pattern " photo-barog^ph. 

Tracing of curve of a " Re- 
dier " barograph, with 
hourly readings of baro- 
meter. 

Trace of record obtained 
from a balance barometer. 



General character of data. 



Lithographed copy of record 
from a photo-barograph. 

Tracing and photographic 
copy of record of photo- 
barograph. 

Original curve from a " Kew 
pattern " photo-barograph. 

Tracing of record from a 
"Re£er" barograph. 

Original curve of a " Kew 
pattern " photo-barograph. 

Original curve of a " Kew 
pattern " photo-barograph. 

Original curve of a "Kew 
pattern ** photo«barograph. 

Original curve of a "Kew 
pattern ** photo-barograph. 



Very clear, but scales small 



Trace carefully made, but 
time scale very contracted. 

Open scale and very good 
curve, but the time is 
doubtful. 

Very contracted time scale, 
but clearly traced. 

Small time scale 



Very good curves, and open 
scales. 

Time scale rather contracted, 
but movements clearly 
shown and trace carefully 
made. 

i Oscillations very well shown, 
I but time scale rather con- 
] tracted. 

Good clear trace 



Open scales, and very good 
copies. 

Open scales, and good curves 



Open scales, and traces care- 
fuUy made. 

Open scales, and good curves 



Open scales, and good curves 



Open scales, and good curves 



Open scales, and good curves 



Duration of Record — 
Greenwich Civil Time. 



From 



Noon, 
20th Aug. 

7 a.m., 
24th Aug. 

10 ajn.» 

26th Aug. 



Midnight, 
25th Aug. 

8 a.m., 
27th Aug. 

Midnight, 
26th Aug. 

Midnight, 
25th Aug. 



Midnight, 
25th Aug. 



8 a.m., 
26th Aug. 

Noon, 
26th Aug. 



Midnight, 
26th Aug. 

Midnight, 
25th Aug. 

10 a.m., 
25th Aug. 

Midnight, 
26th Aug. 

Midnight, 
26th Aug. 

Midnight, 
26th Aug. 



To 



Noon, 

2nd Sept. 

7 a.m., 

5th Sept. 

10 a.m., 
dOth Aug. 



Midnight, 
80th Aug. 

6 a.in., 

31st Aug. 

Midnight, 
30th Aug. 

Midnight, 
30th Aug. 



Noon, 

29th Aug. 



8 a.m., 

1st Sept. 

Noon, 

2nd Sept. 



Midnight, 
1st Sept. 

Midnight, 
2nd Sept. 

10 a.m., 
31st Aug. 

Midnight, 
1st Sept. 

Midnight, 
1st Sept. 

Midnight, 
1st Sept. 



LIEXJT.-GBNBRAL STRACHEY ON THE AIR WAVES. 
Table I. — continued. 



61 



Station. 



Liverpool 

Stonjlmrst 

Olasgow 

Aberdeen 

Toronto 

New York 



Hastings -on 
Hudson, N.Y. 



Washington . . 



Mexico 



Havana 



Cordoba 



Data received, and nature of 
recording instrument. 



Tracings of record of a 
"Bang** barograph. 

Original curve of a " Kew 
pattern *' photo-barograph. 

Original curve of a "Kew 
pattern *' photo-barograph. 

Original curve of a "Kew 
pattern " photo-barograph. 

Photographic copy of record 
of a " Kew pattern ** 
photo-barograph. 

Copies of record obtained 
from a "Draper" pencil 
barograph. 

Copy of record obtained 
from a " Draper ** baro- 
graph. 

Copies of trace from a 
" Gibbon ** electric baro- 
graph. 



.Copy of trace from baro- 
graph, apparently an ane- 
roid recording only hourly. 



Original records of baro- 
graph, anemograph, ther- 
mograph, &o. 



Curve of hourly readings 
obtained from an hourly- 
recording aneroid. 



General character of data. 



Very open scales, and care- 
fully traced copies. 

Open scales, and good curves 



Open scales, and good curves 



Open scales, and good curves 



Open scales, and good copies 
of traces. 



Open scale, and clear trace. • 



Very contracted time scale ; 
clear trace. 



Very open scales, and careful 
copies. 



Very small time scale ; trace 
not continuous, given at 
the hours only. 

Time scale very contracted, 
and barometer trace some- 
what thick, but the earlier 
oscillations are well shown. 

Trace interpolated between 
the hours. 



Duration of Record — 
Greenwich Civil Time. 



From 



9 a.m., 
27th Aug. 

Midnight, 
26th Aug. 

Midnight, 
26th Aug. 

Midnight, 
26th Aug. 

Noon, 
26th Aug. 



Midnight, 
25th Aug. 



3 p.m., 
26th Aug. 



Noon, 
26th Aug. 



1 a.m., 
26th Aug. 



Noon, 
23rd Aug. 



Midnight, 
25th Aug. 



To 



9 a.m., 

4th Sept. 

Midnight, 
1st Sept. 

Midnight, 
1st Sept. 

Midnight, 
1st Sept. 

Noon, 

3rd Sept. 



Midnight, 
Ist Sept. 



3 p.m., 

2nd Sept. 



Noon, 

2nd Sept. 



11 p.m., 
2nd Sept. 



Noon, 

6th Sept. 



Midnight, 
2nd Sept. 



The geographical position of the stations from which the continuous barometric 
registers have been received, and which supply the data now exclusively dealt witlj, 
their latitudes, longitudes, and distances from Erakatoa, in degrees of a great circle, 
are shown in the following Table U. 



62 



LIEUT.-aENERAL STBACHEY ON THE AIR WAVES. 



TABLE II. 

Geographical position of Erakatoa, and of the principal Stations from which data 
have been supplied. 









Distance in Degrees of a Great 








Circle from Krakatoa. 


Station. 


Latitude. 


Longitude. 








THr<v>f. 


Through 








X.'Al^W. 


Antipodes. 


Erakatoa 


6 9 8. 


105 22 8. 


O / 

• • 


o / 

• a 


Batavia . . 








6 9 s. 


106 48 E. 


1 22 


358 88 


Melbourne 








37 60s. 


144 68 E. 


47 53 


312 7 


Sydney .. 








33 54 8. 


161 14 E. 


50 33 


309 27 


Danedin.. 








45 52 8. 


170 37 «. 


68 27 


291 83 


Wellington, N.Z 








41 16 8. 


174 47 b. 


70 31 


289 29 


South Georgia . 








54 31s. 


36 6w. 


111 22 


248 38 


Loanda .. 








8 49 s. 


13 7e. 


91 17 


268 43 


ManritioB 








20 6 8. 


67 33 E. 


48 29 


311 31 


Bombay . . 








18 64 N. 


72 49 E. 


40 42 


319 18 


Calcutta . . 








22 33 N. 


88 21 E. 


33 8 


326 62 


Zi-Ka-Wei 








81 12 N. 


121 26 E. 


40 22 


319 38 


Tokio . . 








. 35 41 N. 


139 46 E. 


62 41 


307 19 


Pawlowsk 








59 41 N. 


30 29 E. 


87 49 


272 11 


St. Peterabnrg . 








59 66 k. 


80 18 E. 


87 57 


272 3 


Bnda-Pesth . 








47 30 H. 


19 2e. 


92 5 


267 55 


Vienna .. 








48 12 N. 


16 22 E. 


93 68 


266 2 


Berlin . . 








52 30 N. 


13 19 E. 


96 7 


263 53 


Leipsic .. 








51 20 N. 


12 24 E. 


96 36 


263 24 


Magdeburg 


. 






52 9n. 


11 88 E. 


97 10 


262 60 


Munich .. 








48 9 k. 


11 34 s. 


97 6 


262 54 


Modena . . 








44 38 N. 


10 55 E. 


97 30 


262 30 


Rome 








. 41 54 N. 


12 29 X. 


96 15 


268 45 


Palermo . . 








88 7h. 


13 21 E. 


96 20 


264 40 


San Fernando . 








36 28 N. 


6 13 w. 


111 1 


248 59 


Lisbon . . 








38 42 N. 


9 8w. 


112 52 


247 8 


Coirobra.. 








40 13 N. 


8 26 w. 


112 3 


247 57 


Serra da Estrella 






40 25 H. 


7 35w. 


111 25 


248 86 


Paris — 














Pare St. Manr 






48 48n. 


2 31 E. 


103 10 


256 50 


Montsonris. 








48 49 N. 


2 20 E. 


103 10 


266 50 


Brussels . . 








50 52 k. 


4 21 E. 


101 48 


258 17 


Greenwich 








51 29 N. 





104 20 


255 40 


Kew 








51 28 k. 


19 w. 


104 32 


265 28 


Geldeston 








52 28 k. 


1 32 E. 


103 16 


256 44 


Oxford .. 








51 46 N. 


1 16 w. 


105 2 


254 58 


Falmouth 








50 9 k. 


5 4w. 


107 45 


252 15 


Valencia.. 








51 55 H. 


10 18 w. 


110 29 


249 31 


Armagh . . 








54 21 N. 


6 89 w. 


107 44 


252 16 


LiTerpool 








53 24 k. 


3 4w. 


105 52 


254 8 


Stonyhurst 








53 51 K. 


2 28w. 


105 24 


254 36 


Glasgow.. 








55 63 k. 


4 18 w. 


106 2 


253 58 


Aberdeen 








67 10 k. 


2 6w. 


104 32 


255 28 


Toronto . . 








43 39 k. 


79 23 w. 


142 12 


217 48 


New York 








40 43n. 


74 Ow. 


146 24 


214 86 


Washington 








38 64 k. 


77 2w. 


147 12 


212 48 


Havana .. . 








23 10 k. 


82 22 w. 


161 20 


198 40 


Mexico . . 








19 25 k. 


99 6w. 


153 24 


206 36 



LIBUT.-GENERAL STRACHBY ON THE AIR WAVES. 63 

The general features of the remarkable atmospheric disturbance caused by the 
great explosion on the morning of August 27th, which appears to have been the effect 
of the final paroxysm of the volcano, and of which alone well-defined indications 
susceptible of identification and measurement have been preserved by the barometric 
registers, will be seen from Plate VII., which reproduces, on an enlarged scale, the forms 
of the trace obtained at selected stations where the record is most nearly perfect, on 
the several successive repetitions of the great aerial oscillation, of which, in many 
cases, seven were distinctly observed. For some time before the great catastrophe, 
minor explosions occurred, of which indications may be found in many of the 
photographic registers, especially those from the stations least removed from Krakatoa, 
the trace being, so to speak, roughened by many small irregularities, giving it an 
appearance very different from that of the smooth line which is its usual character. 

In the communication on this subject before made to the Royal Society, it was 
shown that the observed facts clearly established that the successive repetitions of 
the disturbance at the numerous stations, after varying intervals of time, were caused 
by the passage over them of an atmospheric wave or oscillation, propagated over the 
8ur£eice of the globe from Krakatoa as a centre, and thence expanding in a circular 
form, tni it became a great circle at a distance of 180° from its origin ; after 
which it advanced, gradually contracting again, . to a node at the antipodes of 
Krakatoa; whence it was reflected or reproduced, travelling backwards again to 
Ejukatoa, from which it once more returned in its original direction ; and in this 
manner its repetition was observed not fewer than seven times at many of the 
stations, four passages having been those of the wave travelling from Krakatoa, and 
three those of the wave travelling from its antipodes, subsequently to which its 
traces were lost. 

The barometric disturbance caused by the great explosion began with a more or 
less sudden rise, on the summit of which two or three minor oscillations are visible, 
followed by a deep depression, which was succeeded by a less well marked rise, and by 
other depressions and rises, the whole disturbance extending over a period of nearly 
two hours. Such are the characters of the traces of almost all the self-recording instru- 
ments on the occurrence of the first two waves, and they are very clearly seen in the 
photographic barograms obtained at Bombay, Melbourne, Mauritius, and the British 
Observatories. The traces of these two passages of the wave are, in many instances, 
remarkably alike, although the second oscillation must have crossed the first at or 
near the Antipodes of Krakatoa. The wave, however, gradually became deformed 
during its progress from and to the point where it originated, and eventually lost the 
characters above described. On the third and fourth recurrence the disturbance is 
commonly indicated by a sudden rise, which has the appearance of replacing the 
deep central depression of the first and second passages. 

From the irregularity of the form of the wave, and its want of persistency, 
together with the considerable time over which it extended, there has been some 

k2 



64 LIEUT.-GBNBRAL STRACHET ON THE AIR WAVES. 

unavoidable uncertainty in fixing the exact moment of the passage of the same phase 
of the disturbance in the several waves over the various stations ; but the deep 
depression which immediately followed the initial rise appears, on the whole, to be the 
most persistent and easily recognised feature in the first two passages of the wave ; 
and where it can be identified it has been taken as the standard to which reference 
has been made, especially in fixing the time of the occurrence of the great explosion. 

There can, however, be no doubt that the rise of the barometer, indicating a 
sudden increase of pressure, was the first and direct result of the explosion, and that 
the succeeding fall of the barometer, or decrease of pressure, together with all the 
subsequent oscillations, were mechanical consequences of the original shock, which 
in the nature of the case required some considerable time for their development. 
These remarks have an obvious bearing on the manner in which the exact time of the 
final explosion may be inferred from the observed times of the atmospheric disturb- 
ances, a point to which attention will subsequently be given. 

It may here be remarked that the theoretical investigations of Lord Rayleigh 
indicate that the sudden expansion of an elastic gas, supposed to be confined in a 
spherical envelope, would cause an oscillation which begins with a wave of compression, 
followed by one of expansion ; a form which appears to correspond with that of the 
disturbance now under consideration. According to the same authority the amplitude 
of the wave diminishes as the square root of the distance travelled by it. The data 
do not admit of any positive opinion being formed as to whether this held good in the 
present case, but there is at least nothing to suggest any departure from such a law. 

Plate VIII. gives a representation, on a reduced and uniform scale of time and 
vertical extent, of the observed disturbances as shown on the various barograms, at 
the different stations at which the registers are sufficiently well defined for reproduc- 
tion in this manner. The positions on the traces which have been taken to indicate 
the standard point of the oscillation, selected as before explained, are marked for 
facility of reference ; but it must be explained that the reduction of the trace in most 
cases renders the identifications far less obvious than they actually are on the original 
registers. 

The times at which the successive passages of the wave were observed at the 
several stations (reckoned in all cases in hours and minutes from hours of the 27th 
of August, 1883, Greenwich Mean Time, civil reckoning) are shown in the annexed 
tables. 

Table III. gives the times of passage of the waves travelling from Krakatoa 
towards its antipodes. These passages of the waves are, for convenience, numbered 
as I., Ill, v., and VII. 



LIEUT.-GENEBAL STRAOHBT ON THE AIE WAVES, 



65 



TABLE III. 

Observed times of the successive passages of the waves travelling from Krakatoa 
towards its Antipodes; reckoned fix)m hours of August 27th, 1883, Greenwich 
Mean Time, civil reckoning. 









Passage of Wave. 




- -- 


Station. 




























I. 




m. 


V. 




vn. 




hrs. 


min. 


hrs. min. 


hrs. 


min. 


hrs. min. 


Melboame 


8 


14 


43 12 


• • 




• • 


Sydney . . 
Dnnedin. . 


8 
10 


24 
15 


43 18 
45 15 


78 


39 

? 


• • 

p 


WeUiniflon, N.Z 


10 


20 


45 45 




• ? 


J) 


Soath Georgia . . 


15 


24 


48 24 




? 


? 


Loanda . . 


12 


18 


47 15 


82 


23 


117 23 
mean. 


ManritiTis 


8 


17 


42 60 


77 


26 


112 10 


Bombay 


7 


26 


44 




? 


? 


Calcutta 


6 


47 


43 22? 




? 


? 


Zi-Ka-Wei 


7 


27 


42 54 P 


• « 




• • 


Toldo 


8 


51 


44 12? 




P 


? 


Pawlowsk 


12 


18 


49 18 


86 


38 


• • 


St. Petersburg . . 


12 


14 


48 39 


85 


44? 


• « 


Bada-Pesth 


12 


30 


48 55 


84 


45? 


• • 


Vienna . . 


12 


34 


49 9? 


• • 




• • 










mean. 




Berlin 


12 


52 


49 37 


86 


14 


122 .37? 


Leipsic .. 


14 


0? 


? 




9 


• • 


Magdebntg 


12 


59 


49 28 


84 


31 


? 


Manich 


12 


35 


49 30 


85 





, , 


Modena 


12 


51* 


49 11* 


85 


26» 


121 86» 


Bome . . . . . . . . 


13 





48 55 




P 


P 


Palermo 


13 


37 ?t 


? 




P 


? 


San Fernando . . 


13 


22 


49 12 


• • 




• • 


Lisbon .. 


14 


17 


50 12 




P 


• • . 


Serra da Estrella 


13 


50? 


50 0? 




P 


• • 


Coimbra. . 


14 


20 


50 10 




P 


, , 


Paria— 














Pare St. Manr 


13 


41 


50 1 


86 


61 


• • 


MontsoQiis 


13 


34 


49 54 


, , 




• • 


Brossels 


13 


28 


50 5 


86 


36 


? 


Greenwich 


13 


45 


60 13 


87 


2 


124 6P 


Kew 


13 


48 


50 12 


87 


10 


124 10 


Geldeston 


13 


39 


50 2 


86 


59 


123 31 


Oxford 


13 


53 


50 15 




? 


• ■ 


Falmouth 


14 


4 


50 25 




P 


P 


Valencia 


14 


25 


60 51 


87 


42 


9 


Armagh . . 


14 


15 


50 45 


87 


22 


124 30? 


Liverpool .. 

Stonyhnrst 


13 


58 


50 25 


87 


20 


124 5P 


13 


55 


50 27 


87 





124 10 



• Times given by Professor Bagona, Director of Bojal Observatory, Modena. 
t This time differs slightly from that given by Professor Cacciatore of Palermo Observatory. 
time scale of the enrve is very contracted. 



The 



66 



LIEUT-GENERAL STBACHET ON THE AIR WAVES* 



Table III. — continued-. 



station. 



Passage of Wave, 



III. 



VIL 



Glasgow 

Aberdeen 

Toronto . . 

New York 

Hastings-on-Hudson, N.Y 

Washington 

Mexico • . 

Havana . . 

Cordoba 



hi*8. min. 
14 2 



hrs. min. 
50 38 



13 
1? 
17 
17 

18 

19 



52 
83 
53 
56? 


? 

0?» 

? 



50 
55 
55 
55 
55 

55 



32 
18 

21 

41? 

33 

? 

50? 

? 



hrs. min. 
87 15 



87 
^92 



12 




92 11 



hrs. min. 
124 20 



124 
127 



128 



20 
43 

P 

? 
0? 

? 

? 

? 



* This oscillation occurred a little after 19 honrs, but the time scale is too contracted to allow of 
the time being obtained with much exactness. 

Note. — ^A ? inserted alone in the column indicates that the ''Wave" cannot be identified in the 
trace. When a blank is inserted in the column it indicates that no trace has been received for that 
period. 

Table IV. gives the times of the passage of the waves returning towards 
Erakatoa from its Antipodes. These are numbered as II., IV., and VI. 



TABLE IV. 

Observed times of the successive passages of the waves returning towards 
Erakatoa^ after having passed its Antipodes; reckoned from hours of August 
27th, 1883, Greenwich Mean Time, civil reckoning. 



Station. 



Melbourne • 
Sydney . . 
Dnnedin 
WeUington, N.Z 
South G^rgia • 
Loanda •. 
Manritins 
Bombay . . 
Calcutta.. 
Zi-Ka-Wei 




Passage of Wave. 



VI. 



hrs. mill. 




• • 




? 




? 




? 




? 




102 ' 23 




105 55 




P 




? 




• • 





LIEUT.-GENBBAL STEACHEY ON THE AIR WAVES. 
Table IV. — continued. 



67 



Station. 




Passage 


of Ware. 












XL 


IV. 


VI. 






hrs. min. 


hrs. min. 


hrs. min. 




Tokio 


34 20 


? 


P 




Pawlowsk 


29 28 


63 53 


• • 




St. Petersburg 


29 24 


63 49 


• • 




Bada-Peath 


28 20 


64 10 


• • 




Vienna 


29 9 


• • 


, , 




Berlin 


28 37 


63 14 


P 




Leipsic 


28 40? 


? 


P 




Magdebnrg 


28 36 


63 18? 


98 8? 




Mnnich . . 


28 30 


63 40 


P 




Modena 


28 16* 


62 36» 


97 31» 




Borne 


28 55 


? 


? 




Palermo.. 


29 27?t 


? 


? 




San Fernando . . 


27 


62 2 


• • 




Lisbon 


27 17 


62 32 


• • 




Serra da Estrella 


27 30? 


62 0? 


P 




Coimbra .. 


27 15 


62 23 


• ♦ 




Paris: — 










Pare St. Manr 


28 21 


63 4 


• • 




Montsonris 


28 21 


• • 


« • 




Bmssels . . 


28 23 


62 40? 


97 53 




Greenwich 


27 68 


62 45 


98 




Zew 


28 5 


62 42 


98 




Geldeston 


28 6 


62 44 


98 4 




Oxford 


28 5 


62 35 


? 




Falmonth 


27 43 


62 27 


98 




Valencia. . 


27 15 


62 10 


97 13 




Armagh . . . . . . . . , . 


27 32 


62 22 


97 7 




Liverpool 

Stonyhnrst 


27 41 


62 40 


97 10? 




27 45 


62 35 


97 10 




Glasgow 


27 45 


62 26 


97 8 




Aberdeen 


27 52 


62 32 


98 20 




Toronto 


25 48 


57 53 


91 18 




NewTork 


25 26 


58 18 


P 




Hastings-on-Hadson, N.T. . . 


25 26? 


58 16? 


P 
f9l 81 




Washington 


25 20 


57 61 


\ or \? 
1.90 23j 




Mexico .. 


P 


P 


P 




Havana .. 


24 15? 


67 0? 


? 




Cordoba 


P 


P 


? 





* Times given by Prof. Bagona, Director of "BiOjal Observatory, Modena. 

t This time differs slightly &om that given l^ Prof. Cacdatore, of Palermo. The time scale of 
the cnrve is very contracted. 

NOTK. — ^A ? inserted alone in the colamn indicates that the "Wave" cannot be idoitified in the 
trace. When a blank is inserted in the column, it indicates that no trace has been received for that 
period. 

From the times thus recorded may be deduced the probable precise moment of 
the oocurrence of the great explosion, of which there is otherwise no satis&ctory or 
complete evidence, as well as the velocities of the wave's transmission in its course 
round the earth. 



68 



LIEUT-GENERAL STRACHEY ON THE AIE WAVES. 



But, as will be more fully shown hereafter, the velocity of transmission was not 
uniform in all directions, nor did it remain constant as the wave advanced. In 
order, therefore, to determine the most probable moment of the origin of the wave, 
it has been considered best to deal only with the data obtained from the stations 
nearest to, and immediately surrounding, Krakatoa: — ^viz., Calcutta, Zi-Ka-Wei 
(Shanghai), Bombay, Melbourne, Mauritius, and Sydney ; at all which the records of 
the first passage of the wave are well defined and satisfactorily comparable, while 
their distances from Krakatoa are not so great as to make it likely that important 
variations of the velocity of the wave took place during the time occupied in 
reaching them. 

If T is the time of the origin of the wave, which is to be determined ; t, the 

time of the passage of the wave at any station ; c?, the distance in degrees from the 

point of origin ; and V, the velocity of the wave's transmission, assumed to be the 

same in all cases ; then 

d 



V = 



«-T 



and representing by d^^ c^^, • . • • d^^ the several distances of the six stations fi*om 
Krakatoa ; by t^, tg, . . . • <6> tbe several observed times of passage of the wave ; and 
by ^{d) and ^{t) the sums of the distances and times, we shall have for the most 
probable values of T and V. 

T = ^')' ^^^J^^f^''^ = 3.54 hours = 3hrs. 32min. G.M.T. 

V = ^t^^f^zWf,J^ = 10'31 degrees, or 713 English miles per hour. 
6 2\at) — S \t). A \d) 

The residual errors of observation, assuming the above values, are shown in the 

following Table V. 





TABLE 


V. 










Station. 


d. 


t. 


t-T. 


d-i-V. 


Error in 
Time. 


d 


Error in 
Velocity. 







Hn. 


Hn. 


Hrs. 


Hr. 








Calcutta 


3313 


6-78 


3-24 


3-21 


-03 


10-23 


-08 


Zi-Ka-Wei 


40-37 


7-45 


3-91 


8-92 


+ •01 


10?2 


+ 01 


Bombay 


40-70 


7-43 


3-89 


3-95 


+ 06 


10-46 


+ 15 


Melbourne 


47-88 


8-23 


4-C9 


4-64 


-06 


10-21 


-10 


Mauritius 


48-48 


8-28 


4-74 


4-70 


-•04 


10-23 


-•08 


Sydney 


50-65 


8-40 


4-86 


4-90 


+ 04 


10-40 


+ 09 



From which it may be concluded that the probable error of the deduced time of 
origin of the wave is ± '04 hour, or about 2^ mins. ; and that of the velocity of 
the wave ± '09 degree, or 6 miles per hour. 



LIEUT..GBNERAL STRACHEY ON THE AIR WAVES. C9 

As was before observed, however, the phase of the oscillation taken as the 
standard, in reckoning the times of the wave's passage over the several stations, is 
not the initial extraordinary rise, but the lowest part of the depression following it. 
It is not easy to define precisely the true commencement of the disturbance which 
precedes the passage of the standard phase of the oscillation over the several stations, 
and there may be an error of at least 5 minutes in the determination that has been 
adopted as most probable. This, however, gives for the mean of five of the last- 
mentioned stations 36 minutes earlier, and all agree within 4 minutes of that value. 
Sydney is excluded from this determmation, as the trace is too irregular to admit 
of a satisfactory result being obtained. 

Consequently the probable moment of the great explosion was 3 hrs. 32 mins., 
mtntuf 36 mins. = 2 hrs. 56 mins. G. M. T., or 9 hrs. 58 mins. local time. 

A corroboration of the conclusion thus arrived at, is afibrded by the register of 
the gasometer indicator at Batavia, which fortunately is available, and which in the 
absence of a continuous barometric record, supplies a fairly trustworthy indication of 
the atmospheric pressure at the time in question. Plate IX. is a slightly reduced 
facsimile of a portion of this register for the first half of August 27th.* 

The distance of Krakatoa from Batavia being 1^ 22', the wave, with the velocity 
before calculated, would reach the latter place in 8 mins., so that it would have been felt 
there at 3 hrs. 4 mins., G. M. T., or 10 hrs. 11 mins., local time. The gasometer shows 
a sudden and most extraordinary increase of pressure at some time between 10 hrs. 15 
mins. and 10 hrs. 20 mins. a.m., local time, agreeing as exactly with that above arrived 
at ajs could be expected from the somewhat rough character of the trace, the inertia 
of the recorder, and the possible error of the clock at a non-scientific establishment. 

The oscillations of the gasometer indicator were very numerous and violent on 
the day of the great explosion, but following the maximum increase just referred to, 
there appears to have been a maximum reduction of pressure between 10 hrs. 40 mins. 
and 10 hrs. 50 mins. local time, corresponding therefore with the maximum fall shown 
in the barometric traces of the wave. It has not been possible to connect any other 
of the gasometer indicator oscillations with any available recorded barometric disturb- 
ances, and from this it must be inferred that the explosion at 2 hrs. 56 mins., G. M. T,, 
was far more violent in its character than any of the others. 

The intervals of time between the origin of the great wave and its^r^^ passage 
over the several stations, direct from Krakatoa ; as well as the time intervals between 
the successive subsequent recurrences bf the wave in its progress round the earthy 

* On the original the trace at about 10 hrs. 15 mins. passes beyond the limits of the diagram, and 
it is quite possible that the atmospheric pressure on the gasometer at that moment may have been 
snfficient to have caused the pencil to rise even higher than it did, had the construction of the recording 
apparatus allowed of its doing so. The ^gures on the right of the diagram gi^e the indicated pressure 
on the gasometer in millimetres of water, while those on the left give the equivalent pressures in 
inches of mercury. It must b^ remembered, however, that, in order to get the absolute pressure on 
the gasometer, the figures must in each case be doubled. 

L 



70 



LIEUT-GENERAL STRACHEY ON THE AIR WAVES. 



after passing through the Antipodes and again returning through Krakatoa ; together 
with the deduced velocities of the wave's transmission, are shown in Table YI. 

TABLE VI. 

Time intervals, and velocities between the origin and jirst passage of the wave, 
and between its successive recurrences travelling in the same direction. 

The velocities are expressed in degrees of the Equator and decimals, per hour. 



Station. 



Melbourne • • 

Sydney 

Danedin • • 

Wellington, N.Z. 

South ueorgia 

Loanda 

Manritins 

Bombay 

Calcutta 

Zi-Ka-Wei 

Toldo 

Pawlowsk 

St. Petersburg 

Buda-Pesth 

Vienna 

Berlin 

Leipsic 

Magdeburg . . 

Munich 

Modena 

Rome 

Palermo 

San Fernando 

Lisbon 

Serra da Estrella . . 

Coimbra 

Paris: — Pare St. Maur 

Montsouris 
Brussels 
Greenwich . . 

Kew 

Oeldeston . . 

Oxford 

Falmouth . . 

Valencia 

Armagh 

Liverpool . . 

Stonyhnrst . . 

Glasgow 

Aberdeen . . 

Toronto 

New York . . 

Hastings-on-Hudson, N.Y. 

Washington 

Havana 



Between time of 


Between 


PMHcee 


Between 


I«MM« 


Between 


PMM«« 


origin and 


pueagel. 


I. andlll. 


ULwuiV. 


V. and VII. 


Inteiral 


Hourly 
nte. 


InterrmL 


Houriy 
rmte. 


InterraL 


Hourlj 
rate. 


Interna. 


Hourly 


houn. 
4-70 


degree*. 
10- 19 


houn. 
34-97 


degrees. 
10-29 


houn. 

• • 


degrees. 


houn. 

• • 


degreet. 


4-87 


10-38 


34-90 


10-32 


36-35 


ib*-i8 


• • 


e • 


6-72 


10-19 


35 00 


10-29 


• • 


, , 


, , 


• • 


6-80 


10-87 


35 -42 


10-16 


• • 


• • 




, , 


11-87 


9-38 


33-00 


10-91 


• • 


, , 


• • 


• • 


8-77 


10-41 


34-95 


10-30 


85-13 


10-25 


35-00 


10-29 


4-76 


10-21 


34-66 


10-42 


34-58 


10-41 


34-76 


10-36 


3-90 


10-44 


36-57 


9-84 


, , 


, , 


• • 


• « 


8-25 


10-19 


86-58 


9-84 


, . 


• • 


, , 




3-92 


10-30 


36 45 


10 16 


, , 


. • 




, , 


6-32 


9-90 


35 -36 


10-18 


, , 


, , 


, , 


, , 


8-77 


10-01 


37-00 


9-73 


36-83 


9-91 




, , 


8-70 


10-11 


36-42 


9-88 


37-08 


9-71 


, , 


• . 


8-97 


10-27 


36-42 


9-88 


36 83 


10-06 


• • 


, , 


903 


10-41 


36-58 


9-84 


, , 


• • 


• • 


, , 


9-83 


10-30 


36-75 


9-80 


86-62 


9-83 


36-38 


9-90 


10-47 


9-23 


• • 


, , 


• • 


• • 


• • 


• • 


9-45 


10-28 


36-48 


9-87 


35 -05 


10-27 


• • 


• • 


9-05 


10-73 


36-92 


9-75 


35-60 


10 14 


• • 


• • 


9-32 


10-46 


36-33 


9-91 


36-25 


9-93 


86 17 


9-96 


9-47 


10 16 


35-92 


10 02 


• • 


• • 


• • 


, , 


10-08 


9-46 


• • 


• • 


. , 


, , 


• • 


, , 


9-83 


11-29 


35-88 


10-05- 


, , 




, , 


, , 


10-75 


10-50 


35-92 


10 02 






, , 


^ 


10-30 


10-82 


36-17 


9-95 


, , 


• • 




• • 


10-80 


10-38 


35-83 


10-06 


• • 


• • 




, , 


10-15 


10 16 


36 33 


9-91 


86-88 


9-77 




, ^ 


10 03 


10-29 


36-33 


9-91 


• • 


, , 






9-93 


10-24 


36-62 


9-83 


86-52 


9-86 


• • 


, , 


10-22 


10-21 


36-47 


9-87 


36-82 


9-78 


87-05 


9-72 


10-27 


10 18 


36-40 


9-89 


36-97 


9-74 


37-00 


9-73 


10 12 


10-20 


36-38 


9-90 


36-95 


9-74 


36-58 


9-85 


10-35 


10-15 


36-37 


9-90 


• • 


, , 


,, 


• • 


10-53 


10-23 


36-85 


9-90 


• • 


, , 


• • 


, , 


10-88 


10-16 


36-43 


9-88 


36-85 


9-77 


• • 


, , 


10-72 


10-05 


36-50 


9-86 


36-62 


9-88 


87-13 


9-70 


10-43 


10-15 


86-45 


9-88 


86-92 


9-75 


36-75 


9-80 


10-38 


10 16 


36-53 


9-86 


86-56 


9-86 


37 17 


9-69 


10-60 


10-10 


36-60 


9-84 


36-62 


9-83 


37-08 


9-71 


10-33 


10-12 


36-67 


9-82 


86-67 


9-82 


37-13 


9-70 


14-02 


10-14 


37-75 


9-54 


36-70 


9-81 


35-72 


10 08 


14-36 


10-13 


37-47 


9-61 


• • 


• • 


., 


• • 


14-40 


10-10 


37-75 


9-64 


, , 


e • 


• • 




14-47 


10-17 


37-55 


9-59 


36-68 


9-83 


86 -82 


10-05 


15-47 


10-43 


36-83 


9-7? 


• • 


• • 


• • 


• • 



The corresponding time intervals between the origin of the wave and its second 
passage over the several stations, after having travelled from Ejrakatoa through its 



LIEUT.-GBNERAL STRACHEY ON THE AIR WAVES. 



71 



Antipodes; as well as the intervals between the successive subsequent passages of the 
wave, after travelling in the same direction round the earth, through Krakatoa, and 
again returning through its Antipodes ; together with the deduced velocities of the 
wave's motion, are shown in Table VII. 

TABLE VII. 
Time intervals and velocities between the origin and second passage of the wave, 
and between its successive recurrences travelling in the same direction. 

The velocities are expressed in degrees of the Equator and decimals, per hour. 



station. 


Between time of origin and 
pungell. 








Interval. 


Hoorir nt». 


InMml. 


Hoorif ntt«. 


Interm. 


Hoorly rwe. 




Hoora. 


Degrees. 


Houn. 


I^WrtM. 


Houn. 


Degrees. 


Melbonme 


30-88 


10- 11 


36-26 


10 -21 




* • 


Dunedin • • . • • . 


30-88 


10-19 


35-50 


10-14 


. • 




28-47 


10-24 


86-00 


10-00 






Wellington, N.Z. 
South Georgia 

Loanda 

Maoritins • • 
Bombay . . 
Calcutta .. 


28-72 
24-28 
27-02 


10-08 

10-24 

9-96 


35-75 
36-18 
36-08 


10-07 
9-95 
9-98 


• • 

35-76 


• • 

10*07 


80-97 
30-85 
81-27 


10-06 
10-85 
10-45 


86-17 
35-17 

• • 


9-95 

10-24 

• • 


35-25 

• • 


10-21 


Zi-Ka-Wei 


32-12 


9-95 


• • 


• « 


•• 


• • 


Tokio 


80-80 


9-98 


• • 


• • 






Pawlow&lc • • 


25-93 


10-60 


34-42 


10-46 






^ «P WW *^^ WW 9^m^ • ■ • » » • 

St. Petersburg 

Buda-Pestli 


25-87 
24-80 


10-62 
10-80 


34-42 
35-83 


10-46 
10-06 


-• 


, , 


Vienna • . 


25-62 


10-88 


• . 


• • 


• • 


• • 


Berlin 


25-08 


10*62 


34-62 


10-40 


• • 


.. 


Leipsio •. 
Magdeburg . , 


26-13 
26 07 
24-97 


10-48 
10-48 
10-53 


34-70 
35-17 


10*87 
10-24 


34-83 

• • 


10-34 


Modena • . 


24-73 


10-61 


34-83 


10-49 


34-92 


10-31 


Rome 


25-88 


10-39 


• • 


• • 




• • 


Palermo • • - . . • • • • 


25-92 


10-21 




• • 






Snn Fernando 


28-47 


10-61 


35-03 


10-28 






TiiaVkOIl . . . . • . • 


23-76 


10-41 


85-26 


10 21 






Serra da Estrella 


23-97 


10-37 


84-50 


10-43 




■ • 


Coimbra • • 

Paris :— Pare St. Maur . . 


23-72 
24-82 


10-45 
10-36 


36-13 
34-72 


10-26 
10-87 


• • 


• • 


Montsouris 

Brussels 

Ghreenwich 
Kew 

Geldeston 

Oxford 

Falmouth 

Valencia 

Armagh . . 
Lirerpool - . 

Stonyhurst 

Glasgow . . 

Abei^een 

Toronto • • • • • • • * 


24-82 
24-85 


10-35 
10-39 


34"-28 


10*-60 


85-22 


10-22 


24-48 


10-47 


84-78 


10-85 


35 -25 


10-21 


24-55 


10-41 


34-62 


10-40 


86-80 


10-20 


24-57 
24-65 


10-46 
10-39 


84-63 
84-60 


10-40 
10-48 


85-83 

• • 


10-19 


24-18 


10-43 


84-73 


10-37 


85-55 


10-18 


28-72 


10-62 


34 92 


10-81 


36-06 


10-27 


24-00 


10-61 


34-83 


10-34 


34-75 


10-36 


24 15 


10 62 


34-98 


10-29 


84-50 


10-43 


24-22 
24-22 


10-61 
10-49 


34-83 
34-68 


10-34 
10-38 


34-58 
34-70 


10-41 
10 -37 


24-33 


10-50 


34-67 


10-38 


35-80 


10 OG 


22-27 


9-78 


32 08 


11-22 


38-42 


10-77 


New York 


21-90 


9-80 


32-87 


10-96 


• • 


a • 


Hastings-on-Hudson, N.Y. 


21-90 


9-80 


32-83 


10-97 


/ 32*63 
lor 33 -28 


li-07 


Washington 


21-80 


9-76 


32 52 


11-07 


or 10 -82 


Havana 


20-72 


9-69 


32-75 


10-99 


•• 


•• 






L 2 











72 LIEUT.-GENBRAL STELiOHBT ON THE AIR WAVBS. 

The velocities of the wave thus obtained will be seen to range from about ^^'7i 
per hour to lO'^^ per hour, or from 674 to 726 English miles per hour. The velocity of 
sound in air, of a temperature of 50° Fahrenheit, is 757 miles per hour, and at 80° Fahren- 
heit it is 781 mDes; at a temperature of zero Fahrenheit it is reduced to 723 miles 
per hour. Thus it appears that the atmospheric disturbance now in question had very 
nearly the characteristic velocity of sound, and that its mode of propagation by an 
aerial oscillation, of comparatively short duration, was also closely analogous to that 
of sound. Moreover, although there is no direct evidence that the great final 
explosion, which produced this atmospheric disturbance, was accompanied by sounds 
heard at any considerable distance, it is well established that during the progress of 
the eruption the sounds of some of the explosions were heard at very great distances ; 
certainly at Ceylon, about 2,000 English miles from the volcano, and at many places 
between 1,000 and 1,500 miles distant; and probably at Bodriguez, about 3,000 
English miles distant. Further details on this subject will be found in the subsequent 
section upon Sounds. 

The results given in Tables YI. and VII,, when examined more closely, indicate 
that there were sensible variations in the velocity of the wave's transmission in the 
same direction over the various stations, and that the velocity of the waves moving 
in different directions over the earth's surface likewise diflPered considerably. Some of 
the apparent variation is, no doubt, due to the imperfection of the data, and the 
difficulty before mentioned of identifying the standard phase of the wave, on the 
moment of the occurrence of which such calculations as these must be based. But 
the differences are too great and too consistent to be entirely, or even mainly, attri- 
buted to these causes. 

This will be made apparent from the following considerations. The velocity of 
the wave, in degrees per hour, in passing round the earth, is 360^ divided by the time 
of transit. If this time be assumed to be approximately 36 hours, and the variation 
from it, whether positive or negative, be called x, in hours, the velocity will be 

o^^ =10°— y, where y is the corresponding variation of the velocity from 10° 

lOx 
per hour. Consequently, y= Q^ ■ > and hence an error of 10 mins. in the time 

would produce a change in the deduced velocity of only 0°*046 per hour, and 
an error of half an hour would change the velocity by only 0°137 per hour. 
The probable limits of error in the estimation of the times are, in almost all 
cases, well within thirty minutes, and the few exceptions that are found have no 
practical influence on the general conclusions adopted. 

It will be seen that there is great general similarity in the respective time 
intervals and velocities for the whole series of stations, comprised in the two tables 
between Pawlowsk and Aberdeen, which includes all the European stations on 
which the most confidence can be placed. The paths of the portions of the 



LIEUT.-GBNERAL STRACHEY ON THE AIR WAVES. 73 

wave that passed over these places do not vary greatly in azimuth, and, pre- 
sumably, the general conditions of temperature also will not have varied greatly 
among them. 

Now, from Table VI. it will be found that the mean velocity of the wave for 
twenty-nine of these stations, in passing for the first time from Krakatoa to them, is 
10°'23 per hour. The average velocity in the same dii-ection between the first and 
third passages, over twenty-seven of the same stations, during which the wave com- 
pleted the circuit of the earth, was reduced to 9°'89 per hour ; the mean time 
occupied in the passage being 36 hrs. 24 mins. For the next passage round the 
earth the mean velocity for eighteen of the stations was 9°*86 per hour, and the time 
occupied 36 hrs. 30 mins. ; while, for the last observed passage over ten stations 
the mean velocity was 9°77 per hour, and. the period which elapsed was 36 hrs. 
50 mins. 

The corresponding quantities for the alternate passages of the wave, extracted 
from Table VII., are as follows : — The mean velocity of the wave, while travelling from 
Krakatoa through its Antipodes, to the same twenty-nine stations as before dealt 
with, is 10^*47 per hour ; for twenty-four stations the mean velocity between the second 
and fourth passages, during which also the circuit of the earth was completed, is 10*^*3 5 
per hour, the mean time occupied being 34 hrs. 46 mins. ; while, for the next passage, 
which is also the last observed in this direction, thirteen stations give a mean velocity 
of 10°'27 per hour, with a period of transit of 35 hrs. 4 mins. 

It will further be seen that the velocities derived from the observations at 
Calcutta and Bombay, which lie within the zone traversed by the portion of the wave 
that passed over the European stations, correspond generally in character with those 
that have just been described, and that the reduction of the velocity between the first 
and third passages was almost the same. 

On the other hand, at the Australian and New Zealand stations which lie within 
the same zone of the earth's surface, but to the eastward of Krakatoa, and over which, 
therefore, the movements of the several passages of the wave were in almost directly 
opposite directions to those over the European stations, the velocity between the first 
and third passages hardly differs from that between the origin and the first passage, 
in both which the motion of the wave was ivith the earth's rotation ; while between 
the origin and the second passage, as well as between the second and fourth passages, 
during which the wave travelled round the earth against the direction of rotation, the 
velocity is sensibly less than that observed over the European stations, where, between 
the same passages of tlie wave, its motion was in the opposite direction. 

The difference of the velocities of the waves that travelled with and against the 
direction of the earth's rotation amounts to about four-tenths of a degree, or 28 English 
miles per hour, and it may probably be accounted for by the circmnstance that the 
winds along the paths of this portion of the wave would, on the whole, have been 
westerly, which would have caused an increase of velocity in the wave moving with the 



74 LIEUT..GBNBRAL STRACHEr ON THE AIR WAVES. 

earth's rotation, and an equal diminution in that moving in the opposite direction, so 
that the observed difference of 28 miles could be produced by an average westerly 
current of 14 miles per hour, which is not imlikely. 

There is some appearance of a greater retardation of the wave in passing in a 
direction opposed to the earth's rotation over the northern European stations as com- 
pared with those in the south of Europe, which may possibly be due to the lower 
temperature of the more northern part of the zone traversed. This difference is not 
to be traced in the wave n\oving in the opposite direction, which may be accounted for 
by the path of the wave, when approaching Europe from the vest, having lain for a 
long distance over the Atlantic, where the differences of temperature between the 
northern and the southern borders of the zone traversed would have been relatively 
small. 

The velocities observed at Mauritius and Loanda, the paths of the waves passing 
over which lie respectively within 20° and 10® of the Equator, are very nearly alike ; 
the wave travelling to the west not being sensibly retarded, while that travelling to 
the east is so retarded. This may be caused by the paths pf the waves falling entirely 
within the zone of the Trade Winds, which both north and south of the Equator blow 
from the east, and would therefore cause a relative retardation of the wave travelling 
with the earth's rotation. 

The path of the wave that passed over the Canadian and United States stations, 
and Havana, lies nearly on the meridian drawn through Krakatoa, and must have 
crossed both the polar circles very near the poles. The velocities obtained from these 
stations are peculiar. The dbect wave from Krakatoa, which travelled nearly due 
north and close to the north pole« and its repetitions after passing round the earth in 
the same direction, had nearly the same velocities as those observed at the European 
stations, with an apparent decided retardation in the intervals between the first and 
third passages, and (but to a less extent) between the third and fifth. The wave 
that passed through the Antipodes before reaching the North American stations went 
nearly due south, close to the south pole ; and its velocity on this its first partial 
passage round the earth was very decidedly reduced ; but in its next complete circuit, 
that between the second and fourth passages over the stations of North America^ the 
velocity appears to have been much increased, almost reaching the full rate of the 
true sound-wave. It is difficult to account for this, but the fact seems to be indis- 
putable. 

The peculiarities affecting the velocity of the waves will be subsequently again 
referred to ; and diagrams are given which show graphically the manner of their 
occimrence, and supply further evidence of the truth of the conclusions that have now 
been stated. 

The variations of velocity in the waves moving in opposite directions are clearly 
shown by the following Table VIII., which gives the time intervals between the 
passage of the successive waves, irrespective of their direction. When the time 



LIEUT.-GBNERAL STRACHEY ON THE AIR WAVES. 



75 



interviews increase, either the first, third, and fifth passages are accelerated, or the 
second, fourth, and sixth are retarded ; and when the intervals diminish, the converse 
holds good. 



TABLE VIII. 

Time intervals between the passages of the successive waves, irrespective of 
their direction. 











Interval between Passages. 






fifft'fioTl 




















Kj %ftm VA\ja • 


I.- 


II. 


II.- 


III. 


iii-rv. 


IV.-V. 


V.- 


VI. 


VI.-VII. 




hr. 


min. 


hr. 


min. 


ht. min. 


hr. min. 


hr. 


min. 


hr. min. 


Pawlowsk 


17 


10 


19 


50 


14 36 


21 45 








St. Petersburg 


17 


10 


19 


16 


16 10 


21 56 








Aberdeen . . 


U 





22 


40 


12 


24 40 


11 


8 


26 


Glasgow 


13 


43 


22 


53 


11 48 


24 49 


9 


63 


27 12 


Armagh • . 


13 


17 


23 


13 


11 37 


25 


9 


46 


27 23 


Stonyhnrst 


13 


60 


22 


42 


12 8 


24 25 


10 


10 


27 


Liverpool • • 


13 


43 


22 


44 


12 15 


24 40 


9 


60 


26 66 


Berlin 


15 


45 


21 





13 37 


23 








Geldeston 


14 


27 


21 


56 


12 42 


24 15 


11 


5 


26 27 


Magdeburg . . 


15 


37 


20 


62 


J3 60 


21 13 


13 


37 




Valencia . . 


12 


60 


23 


30 


11 19 


25 32 


U 


31 




Oxford 


14 


12 


22 


10 


12 20 










Greenwich 


14 


13 


22 


15 


12 32 


24 17 


10 


68 


26 6 


Kew 


14 


17 


22 


7 


12 30 


24 28 


10 


50 


26 10 


Leipsic 


14 


40 
















Bmssels 


14 


65 


21 


42 


12 35 


23 56 


11 


17 




Falmonth . . 


13 


39 


22 


42 


12 2 










Paris- 




















Fare St. Maar 


14 


40 


21 


40 


13 3 


23 47 








Montsonris . . 


14 


47 


21 


33 












Vienna 


16 


35 


20 















Munich . . 


15 


56 


21 





14 10 


21 20 








Buda-Pesth 


15 


50 


20 


35 


15 15 


20 35 








Modena . . 


15 


25 


20 


65 


13 26 


22 50 


12 


5 


24 6 


Rome 


15 


55 


20 















Serrs da Estrella 


13 


40 


22 


30 


12 










Coimbra . . 


12 


55 


22 


55 


12 13 










Lisbon 


13 





22 


65 


12 20 










Palermo . . 


15 


50 
















San Fernando .-. 


13 


38 


22 


12 


12 50 










Mean 


14 


41 


21 


46 


12 61 


23 28 


10 


61 


26 15 


Calcutta 


28 


1 


8 


34 












Bombay 


26 


57 


9 


87 


25 33 










Mean . . 


27 


29 


9 


6 


26 33 















7G 



LTEUT.-GENERAL STRACHEY ON THE AIR WAVES. 



Table VIII. — continued. 



Station. 



Interval between Passages. 



I.-II. II.-III. 



III.-IV. IV.-V. 



V.-VI. 



vi.-vn. 



Manritius . . 
Loanda • . 



Mean 



Dunedin . • 
Wellington, N.Z... 

Mean . 

Mcll5bume 
Sydney 

Mean . 
South Georgia .. 



Tokio 
Zi-Ka-Wei 

Mean 



Toronto . . 
New York 
Hastings-on-Hudson, N.Y 

Washington 



Mean 



Havana. . 



hr. min. 
26 13 
i 18 15 



2'2 


14 


21 
21 


45 
55 


21 


50 


26 
25 


11 
31 


25 


51 


12 


26 


25 
28 


29 
12 


26 


5] 



8 15 

7 33 

7 30 

7 20 



7 40 



5 15 



hr. min. hr. min. 

8 20 27 50 

16 42 ! 19 23 



12 


31 


13 
13 


15 
30 


13 


23 


8 
9 


47 
23 


9 


5 


20 


35 


9 

7 


52 
15 


8 


34 



30 13 



29 58 



31 35 



23 


37 


22 
22 


45 
15 


22 


30 


26 
26 


28 

7 


26 


18 


15 


36 



29 


30 


2 


35 


29 


55 


2 


57 


30 


15 


2 


36 



2 18 



2 36 



1 10 



hr. min. 

6 45 

15 45 

11 15 



9 14 
9 14 



34 7 



34 20 



34 14 



hr. min. 
28 30 
20 

24 15 



*0 42 



•1 3 
or 
1 48 






63 




or 


1 


15 



hr. min. 

6 15 

15 

10 38 



36 25 



36 52 
or 

37 37 

36 39 
or 

37 1 



• The order of the waves had been reversed here, so that the sixth wave arrived before the fifth. 



From a comparison of twenty -four European stations, it appears that the mean 
interval between the second and first passages is greater than that between the fourth 
and third passages by 2 hours ; and, similarly, for twelve stations the mean of the 
first of these intervals is greater, by 3 hrs. 40 mins., than the mean interval between the 
sixth and fifth passages. At two of the American stations, Toronto and Washington, 



LIEUT.-GBNERAL STRACHEY ON THE ATB WAVES. 77 

the mean interval between the first two passages of the wave exceeded that 
between the second pair by 5 hrs. 22 mins., and the first of these intervals exceeded 
that between the smaller mean of the third pair of passages by 8 hrs. 41 mins. The 
result of this great variation in the velocity of the waves was that at last the two 
waves from the opposite directions became confused, and must have crossed each other; 
and some doubt therefore exists as to the precise time that should be assigned to their 
respective passages. 

In order to illustrate the manner in which the disturbance travelled round the 
earth, a series of projections, Plates X., XL, XII., and XIII., have been prepared, on 
which the position of the wave is marked for each successive even hour of Greenwich 
mean time, beginning with 4 hrs. of August 27th, civil reckoning, till its traces were 
lt)st. The projection or development, which is quite coiiventional, shows Krakatoa 
and its Antipodes in the centres of two circles, representing the two hemispheres, of 
which those points are the poles. The geographical features of the earth are projected 
on the hypothesis that distances from the centres of the two circles are the distances 
of the points to be represented, measured over the earth's surface on the arc of a great 
circle, from Krakatoa or from its Antipodes, as the case may be. The diameters of 
the circles represent great circles passing through Krakatoa, and therefore indicate 
the paths of the various points of the wave as it advanced. 

The wave of atmospheric disturbance, if it had been propagated without intet- 
ference, would have spread outwards from Krakatoa, in a gradually expanding small 
circle, until it reached a distance of 90° from its origin, and thus have formed a great 
circle ; beyond which it would have contracted as it advanced, till it once more 
coalesced into a point or focus at the Antipodes. Thence it would return in like manner, 
and again be concentrated at its starting point ; and so on, until it gradually died out. 
The departure of the curved lines (which represent the successive positions of the 
wave) from a true circular form, indicates the irregularity in the velocity of the various 
points of the wave's front, and the distortion naturally increases gradually with the 
prolonged duration of the wave's progress. 

The phenomena are otherwise represented in Plates XIV. and XV., which show 
more clearly the variation of the velocities of the wave's movement over the several 
stations, and contrast the velocities of the motion in directions which may be spoken 
of, in geperal terms, as being in conformity with, or in opposition to, that of the 
earth's rotation. 

In these two plates the time-intervals are represented by the ordinates, or 
vertical distances from the base line, which corresponds with the assumed origin of 
the reckoning, viz., hrs. of August 27th, G.M.T., civil reckoning. The distances 
of the several stations from Krakatoa, as measured on arcs of great circles, are the 
abscissse or horizontal distances from the central line, supposed to represent the 
origin of the wave ; those on the right of the central line, Plate XV., being the dis- 
tances measured to the westward, or against the earth's rotation ; those on the left', 

M 



78 LIEUT.-GENERAL STRACHEY ON THE SOUNDS. 

Plate XIV., being the distanceB measured in the opposite direction. An addition of 
360^ is made for each complete passage of the wave round the earth. 

The inclined lines drawn through the point where the central line cuts the 
assumed moment of the origin of the wave, and the points on the proper ordinates 
which represent the time of passage of the wave at the several stations, indicate the 
Velocity of the wave's transmission ; an increased inclination showing reduced velocity, 
and the converse. To distinguish between the waves that passed over different places, 
the lines of velocity are differently drawn, as is explained on the Plate itself. 

The retardation of that portion of the wave which travelled by way of the South 
Pole to the North American stations, already referred to on page 74, is very well 
shown by the diagram, Plate XIV., illustrating the progress of the wave travelling 
with the earth's rotation. The line drawn from Krakatoa to Toronto has at first a 
greater inclination than any other line, indicating that the velocity of the wave was, 
in this part of its course, the least of all ; but afterwards the inclination becomes 
less than that of any other line, showing that the velocity of the wave had changed 
and become the greatest of all. 

The observations at South Georgia, which, speaking in a general manner, lies in 
the same track, confirm those at the American stations ; and indeed it seems that the 
greatest retardation took place in the Southern Ocean, since (as the diagram will 
show), the inclination of the velocity line would have had to be still further increased 
to make it pass exactly through the point representing South Georgia. 

Probably an explanation of this peculiar feature of the phenomena may be found 
in the conditions of the wind and weather in the Southern Ocean, during the days on 
which the wave passed over it, which are not known to us. 



Section II.— SOUNDS. 



In Table IX., p. 80, will be found a list of places at which the sounds of the 
explosions were heard ; and although the list is not a complete one, it is as nearly 
so as it was possible to make it with the information available. The repetition, 
howevw, of places comparatively close to the Strait of Sunda could have given but 
little additional value to the list, which, as it stands, contains all the more distant 
places at which it has been reported that the sounds were heard. 

No sounds were heard before the 26th ; and all the reports agree that the most 
violent detonations occurred on the morning of the 27th. Owing, however, to the 



LIEUT.-GBNERAL STRACHEY ON THE SOUNDS. W 

great uncertainty which is attached to the times at which it is stated that the sounds 
were heard — from the somewhat general way in which they are sometimes given, e,g.^ 
'^^t about 10 a.m.," or *' between 9 and 10 a.m./' &c., the unreliability of the clocks, 
or from other causes — the exact times at which the explosions occurred cannot safely 
be deduced from them ; although, as far as they bear upon the conclusions already 
deduced from other sources as to the time of origin of the great air-wave^ so far from 
their being opposed to those conclusions they appear to support them fairly welL 

The sounds were heard with great distinctness over the most distant parts of 
Java and Sumatra throughout the morning of the 27th, but it is very remarkable that 
at many places in the more immediate neighbourhood of the volcano they ceased to be 
heard soon after 10 a.m., although it is known that the explosions continued with 
great intensity for some time longer. Very probably this peculiar phenomenon was 
caused by the large amount of solid matter which at about that time (10 a,ra, local 
time) was ejected into the atmosphere by the volcano, and which formed in the lower 
strata of the air a screen of suflBcient density to prevent the sound waves from 
penetrating to those places over which it was more immediately suspended. 

The principal places mentioned in the Table have been marked upon Plate XVI., 
which is a map constructed upon a projection similar to that used for showing the 
progress of the air-wave, and having Krakatoa as its centre. 

Small circles have been drawn upon this map with radii of 10"^, 20^. , . , 50^ ■ and 
it will be seen that the 30° line is touched, or closely approached, by places almost 
entirely surrounding Krakatoa ; viz., Ceylon to the north-west, Perth and other 
stations in West and South Australia to the south-east. New Guinea to the east, 
and Manila to the north-east. • Diego Garcia, in the Chagos Group, almost due west 
of Krakatoa, and Alice Springs, in South Australia, are beyond the 30'' line ; while 
Rodriguez, to the south-west of Krakatoa, still more remote, lies beyond the 40^ line* 
The shaded portion of the map represents approximately the area over which the 
sounds of the explosions were heard, and is roughly equal to rather less than one- 
thirteenth of the entire surface of the globe. 

A special interest is attached to the report from Rodriguez, owing to the 
fiict that it is not only the most remote place at which the sounds of the explosions 
were heard, being very nearly 3,000 English miles from Krakatoa, but that it is 
also the only instance on record of sounds having been heard at anything like 
so great a distance from the place of their origin. It may, therefore, be well to 
quote here the account given by Mr. James Wallis, Chief OflScer of Police, who is 
responsible for the following narration : — 

" On Sunday the 26th the weather was stormy, with heavy rain and squalls ; 
the wind was from S.E., blowing with a force of from 7 to 10, Beaufort scale. 
Several times during the night (26th — 27th) reports were heard coming from the 
eastward, like the distant roars of heavy guns. These reports continued at intervals 

M 2 



80 



LIEUT.-GENERAL STRACHET ON THE SOUNDS. 



of between three and four hours, until 3 p.m. on the 27th, and the last two were 
heard in the directions of Oyster Bay and Port Mathurie." 

At Diego Garcia, upwards of 2,250 English miles from Krakatoa, the sounds 
were very distinctly heard, and were supposed to be those of guns fired by a vessel 
in distress ; a belief which likewise prevailed at Port Blair in the Andaman Islands, 
and at several places less remote from Krakatoa. In Ceylon, and also in Australia, 
the sounds were heard at many diflTerent places fer removed from each other ; while 
at Dorey, in New Guinea, they were clearly heard, and their occurrence was recorded 
at the time, long before it was known to what cause they were due. These 
circumstances are of value as confirmatory evidence of the sounds having been really 
heard at those distant places. 

That the detonations were heard so much further to the westward than they 
appear to have been to the eastward of Krakatoa, was most probably due to the 
westward motion of the lower strata of the atmosphere in tlie region of the Trades, 
within which the most distant station, Rodriguez, lies. 

It may be noticed also that a communication was made to the " Academic des 
Sciences," and published in the Comptes Rendus in March, 1885 (vol. c, p. 755), 
giving an account of sounds said to have been heard in the Cayman Islands in 
Lat. 20^ N. Long. 80° W. from Greenwich, South of Cuba, on August 26th, 1883, 
which were* attributed to the eruption at Krakatoa. The evidence, however, is of 
so indefinite a nature that it has not been inserted in the tabular statement annexed. 



TABLE IX. 

List of Places at which the Sounds of the Explosions at Krakatoa were heard 
on the 26th and 27th of August, 1883. 



Placb. 


Distance from 

KrakatoA, 

in English miles. 


Notes. 


JAVA. 




Anjer . . . • 


31 


Tiie sounds of the explosions were heard from the 
afternoon of the 26th. 


Memk 


38 


'' At 7 p.ni. 26th, heavy detonations and violent 
shocks, but no earthquake." 


St. Nicholas Point 


44 


Sounds heard on 26th and 27th, 


Chikandie Udik 


62 


"The reports grew louder and louder, until the 
gronnd shook sensibly. When evening set in 
(26th), the detonations, far from diminishing, 
increased in violence." Report by an English 
resident. 


Batavia .. .. .. 


94 


" On 26th, about 4 p.m., a series of detonations was 
heard; towards night they grew louder; till in 
the early morning the reports and concussions 
were simply de«3ening." Report by Lloyd's 
agent at Batavia. 



LIBUT.-GBNBRAL STRACHBY OX THE SOUNDS, 
.Table IX. — continued. 



81 



Place. 



Serang . . 
Baitenzorg 



Samarang 
Caiimon Java Island 



Near Toelong Agong, 100 miles 
from Soarabaja. 



Sonrabaya (also on board the 
Sea Witch, ashore in the bay). 



Distance from 

Krakatos, 

in English miles. 



Notes. 



Probolingo 

Banjos Wangi, Straitg of Bali 

Yngya Karta 

SUMATRA. 

TelokBetong 

Katimbang, north-east coast of 
Snnda Strait. 

Palembang 

Siak 

Dell • . • 

Acheen • • 

Eotta Radja 

Padang . . 



Bencoolen 
Krod • . 



48 
100 

346 
355 

About 400 (?) 
507 



542 
616 
357 



44 
24 



228 



519 

818 
1,073 

931 

512 



277 
134 



The loudest sounds were heard shortly after 10 a.m. 
on the 27th. . . 

A low rumbling sound heard at 1 p.m., 26th, in- 
creasing in intensity soon afterwards, and con- 
tinuing all through the night, with occasional 
"violent explosions. 

Sounds were heard from the evening of the 26th 
till the afternoon of the 27th. 

Under the belief that a vessel was in distress, several 
native boats were despatched to render assistanc^b 
on the evening of the 26th. 

" The noise sounded like great guns being fired at 
irregular intervals, and it continued all through 
the night, 26th-27th." Extract from letter of 
Mr. Edward St. George. 

The detonations were heard on the 26th and 27th 
so distinctly that it appeared impossible they 
could have come from such a distance as 
Krakatoa. 

The sounds were heard on the 26th and 27th. 

The soands were heard on the 26th and 27th. 



The loudest report was at about 10 a.m., 27th. 

"When it had become quite ^ark on the 26th, 
fearful detonations were heard, like thunder and 
reports of guns." The loudest report was heard 
at about 10 a.m. on 27th. 

The atrial vibrations were so strong as to cause the 
walls of houses to shake. The soands were 
heard from the aflernoon of the 26th till the 
morning of the 27th. 

The sounds were heard from the afternoon of the 
26th till 11 a.m. 27th. ' 

The sounds were heard on the 26th and 27th. 

It was supposed that a fort was being attacked, and, 
in consequence, the troops were put under arms. 

The sounds, were not heard after the night of the 
26th-27th. 

*' At 8.30 a.m., 27th, a heavy explosion, repeated 
five minutes afterwards. .... During aU this 
time a fearful noise was heard from afar, which 
became stronger after 11 a.m." The soun^:^ 
were first heard at 5 p.m. 26th. 

The sounds were heard from the afternoon of the 26th. 

The sounds were heard on the 26th and 27th. A 
report was heard on the morning of the 28th also. 



82 



LIEUT.-GBNERAL STRACHET ON THE SOUNDS. 
.Table IX. — continiied. 



Place. 



BANCA. 



Minto 



Lepa Island 



BILLITON. 
Tanjong Pandang 

STRAITS SETTLEMENTS. 
Singapore 



Distance from 

Krakatoa, 

in English miles. 



284 



242 



277 (abottt) 



522 



Selangore 



Perak 



Penong 



8IAM. 



Bangkok. 



COCHIN CHINA. 

Cape St. Jame8,10* 19' N., 107' 
6'E. 

Saigon , 



715 

770 

868 

1,413 

1,138 
1,164 



Notes. 



The detonations were most violent during the 
night of the 26th. 

The loudest reports were heard near mid-day on 
the 27th. It was thought that a vessel was in 
distress. 



Loudest shortly before noon on the 27th. 



Two steamers were sent on the 27th to look for the 
vessel which was supposed to be firing guns as 
signals of distress. 

" Till 3 p.m. on Monday, the 27th, conversation was 
utterly impossible on the Ishore telephone line. 
On raising the tubes a perfect roar, as of a 
waterfall, was heard, and by shouting at the top 
of one's voice the clerk at the other end heard 
the voice, but not one single sentence was under- 
stood. The same noise, but to a less extent, was 
noticed on eveiy line here, and sometimes, while 
listening to the Ishore line instruments, a report 
like a pistol was heard." (The telephone line 
crosses the strait between Singapore and Ishore 
by a short cable about one soile in length.) 

The sounds were heard from 4.30 p.m. 26th till 
5 p.m. 27th. 

The sounds were thought to be distant salvos of 
artillery. Reports were heard on the 26th and 
27th. 

At 11 a.m. 27th the sounds were mistaken for a salute 
from an American corvette, which, however, had 
sailed four hours previously. 



The reports were heard on the 27th, and are also 
said to have been heard 100 miles in the interior. 



The sounds were heard on the 27th. 



The sounds were heard on the 27th 



LIEUT-GENERAL STRACHET ON THE SOUNDS. 
Table IX. — continued. 



83 



Place. 



Distance from 

Krakatoa, 

in English miles. 



Notes. 



BORNEO 
Martapoera 

Bandjermasin . . 

Jampaga • • 

Soekadana 

Pontianak 

Labuan • . 

Bangaej Island. . 

Elopara . . 

St. Lncia Bay . . 



Samarinda, Koetei 

PHILIPPINE ISLANDS. 
Palawan . • 



Manila, Luzon . . 

CELEBES. 
Manado, V 30' N., 124** 47' E. 



Macassar. 



Island of Lombock 
Island of Timor. • 



684 
666 
683 
461 
493 
1,037 

1,235 

1,210 

1,116 



911 

1,460 (about) 
1,804 

1,435 

969 

790 
1,361 



First heard on 26tli. 

First beard on the 26tb. 

The sounds were heard on the 27th. 

The sounds were heard on the 26th and 27th. 

First heard at 7 p.m. 26th; loudest at 11 a.m. 27th. 

The sounds appear to have been heard only on the 
27th. 

See also the note, page 88, by Commander Hon. F. 
Vereker, R.N., H.M.S. Magpie. 

'* It seemed as if heavy guns were being fired, at a 
distance of not over four or five miles away *' 
(27th). 

" The noise of the eruption was plainly heard all 
over Borneo. The natives inland, who murdered 
poor Witti, when they heard the noise, thought 
we were coming to attack them from the east and 
west coasts, and bolted away from their village " 
(26th-27th). Letter of L. von Donop, North 
Borneo. 

The sounds were heard on the 26th and 27th. 



** The detonations were heard on the 27th, half-way 
up the Palawan coast." 

The sounds were imagined to be signals from a ship 
in distress, and preparations were made to render 
assistance (27th). 

The sounds are said to have been heard not only in 
the town, but over the entire province in which it 
is situated (from the evening of the 26th to the 
27th). 

Two steamers were sent to sea on the 27th to 
ascertain the cause of the reports. The sounds 
were heard over the whole province. 

The reports were heai*d in all parts of the island, as 
well as in the adjoining one of Bali (26th-27th). 

The sounds were heard all over the island. A 
Government steamer was despatched to ascertain 
their cause (26th-27th). 



84 



LIEUT-GENERAL STRACHEY ON TBE SOUNDS. 
Table IX. — continu^^ 



Place. 



Distance from 

Krakatoa, 

in English miles. 



Notes. 



NEW GUINEA. 

Salwatty Island, North-west 
coast. 



Dorey, Geelvink Bay 



1,800 



2,014 



WEST 


AUSTRALIA 


Perth . . 


.. 


Geraldton 


• . • • 


CoBsack .. 





1,902 

1,675 
1,286 



Victoria Plains .. 



•1,700 (about) 



SOUTH AUSTRALIA. 

Alice Springs, 23** 41' S., 133° 

37' E. 

Undoolga, 25 miles east of Alice 
Springs. 

Daly Waters, 16^ 18' S., 133^ 
25' E. 

Elsey Creek, 15* 10' S., 133° 
23' E. 



2,233 

2,250 (about) 
2,023 
2,003 



* The Rajah of Salwatty, whom I met at the village 

of Samatu, told me that the noise of the eruption 
had been audible there.** Dr. F. H. Guillemard, 
M.A., F.L.S. (No date given.) 

* The reports were heard on the 27th by M. van 

Hasselt, residing at Dorey, and recorded at the 
time in his diary. The natives reported to him 
that they had heard similar sounds on the 26th. 
He described the sounds as being like distant 
cannonading.** Extract from letter of Dr. F. H. 
Guillemard, M.A., F.L.S. 



" This coast has been visited (27th) by ... . sounds 
as of the firing of guns inland.'* Staff-Commander 
Coghlan, R.N. 

At Geba^ldton and at Cossack the meteorological 
observers reported that sounds were heard on tha 
27th resembling heavy guns, the reports at 
Geraldton being preceded by a rumbling noise. 
The observer at Cossack says that similar report<s 
were heard along the coast from the Ash burton 
to the Sherlock rivers, and inland as far as the 
Hamhebsley range. 

" People were startled by hearing a series of loud 
reports, resembling those of artillery at a distance 
in a north-westerly direction. The first sounds 
were heai*d by a few persons at 11 p.m. on Sunday 
(26th), continuing at irregular intervals till 
about 4 p.m. on Monday ; sometimes as many as 
three reports occurred in a minute, but generally 
there was a few minutes' interval." Western 
Australian, September 4. 



•' Two distinct reports, similar to the discharge of a 
rifle, were heard on the morning of the 27th, and 
similar sounds were heard at a sheep camp nine 
miles west of the station, and also at Undoolga, 
25 miles east.'* Report by Mr. Skinner. 

" On Sunday, the 26th, at midnight we were 
awakened by an explosion resembling the blasting 
of a rock, which lasted for a few minutes. Next 
morning, between 9.30 and 10 o'clock, a similar 
noise, with slight vibration, was heard and felt, oon- 
tinaing for 15 minutes. Men camped ^ve miles 
south of Daly Waters also heard it, and the noise 
was heard also at Elsey Creek and other places on 
the overland telegraph." Report by Mr. Kemp. 



LIEUT.-GENERAL STRACHEY ON THE SOUNDS. 



85 



Table IX. — continued. 



Place. 



BURMA H. 



Mergui 
Tavoy 



BiBtAnoe from 

Krakatoa, 

in English miles. 



Notes. 



NICOBAB ISLANDS. 

ANDAMAN ISLANDS. 
Port Blair 



CEYLON. 



1,366 
1,478 



1,299 



1,500 



Dutch Bay 



Hambantota . , 

Tissa Mab& lUma (near Ham- 
bantota). 



North Namona Koolie, Badalla, 



Tumpalancholai and Mabd 
Oja (on the Badalla road). 



2,058 

1,866 
1,870 (abont) 

1,904 
1,893 



The sounds were heard on the 26th and 27th. 

** All day on August the 27th unusual sounds were 
heard, resembling the boom of guns. Thinking 
there might be a wreck or a ship in distress, the 
Tavoy Superintendent sent out the police launch, 
but they could see nothing." 



'* Extraordinary sounds were heard, as of guns 
firing" (26th-27th), Extract from report by 
officer in charge. 



*' At 9.30 p,m. on the 26th a report was heard as of a 
distant signal gun. Steamer was sent round the 
coast to search for the vessel supposed to be 
firing as signals of distress. Similar sounds 
were heard at irregular intervals during the two 
following days." Extract from letter of Mr. E. 
g. Man. 

** Several reports were heard in Port Blair, sup- 
posed to be from some ship in distress. Weather 
between August the 27th and 29th very unsettled, 
and heavy rain and wind prevailed." Extract 
from Port Offiper's report, 



The sounds were heard from 7 a.m. to 10 a.m., 27th. 

" Reports heard by three persons from 7 a,m. on the 
26th, and by many persons during the 26th, on the 
night of the 26th'27th, and during the 27th. 
The usual style was a steady sequence of reports, 
and then a rapid saccession of them, ending, very 
often, in a loud bu?«t of two or three, or half a 
dozen, almost together, which was generally fol- 
lowed by a lull. The intensity of the sounds 
varied greatly." — Letter from Mr. H. Parker. 

Heard at noon on the 27th, and continued for half 
an hour, ** I thought it might be some volcano 
in action out at sea, or else ships firing heavy guns." 

** Captain Walker and Mr. Fielder were puzzled at 
various times during the forenoon of the 27th, 
by hearing noises as if blasting was going on, 
though there was nothing of the sort for a very 
considerable distance, if anywhere in the district." 



N 



86 



LIEUT.-GBNERAL STRACHEY ON THE SOUNDS. 
Table IX. — continued. 



Place. 



Distance from 

Krakatoa, 
in English miles. 



Notes. 



Mullijavalai 



1,996 



Bambodde 
Madulsima 

Batticaloa 



1,888 
1,902 

1,888 



Kalmnnai 



1,877 



Kokkulai 
Chemmalai 
Kotinalie Valley 

Bogawanialawa . 

Galle .. 
Mann&r .. 



1,980 
1,980 
1,928 

1,911 

1,932 

2,047 



} 



'' The District Mudalijar reported that sonnds were 
heard, as if cannon were being fired, from 
midnight, Aagost 26th, till noon, Augnst 27th. 
The sounds seemed to come from the east, and 
from no g^reat distance. The apparent proximity 
of the explosions reported from the Mnlliyayalai 
Patta may have been due to the hilly nature of 
the country there.*' Report by Mr. S. Haughton, 
Assistant Qoyemment Agent. 

Sonnds, resembling distant guns, were heard« 

At first the sounds were thought to be those of 
guns fired at Trincomalee. First heard on the 
26th. 

^' At about midnight, 2Gth, I heard about five or six 
times a noise as of a cannon, at intervals of 15 
minutes, towards the east. On the morning of 
the 27th, too, about three times I noticed a noise 
similar to that of the discharge of a cannon over 
the sea towards the east." From Signaller's 
report. ^' The Sub-Collector states that at about 
6 p.m. on the evening of the 26th he heard a loud 
report, as if a cannon was discharged down 
southward, which he and the people near him 
thought to be thunder.*' Report by Mr. Elliott, 
Acting Governn^ent Agent. 

''Mr. Christie, of the Public Works Department, 
told me he had heard loud explosions seawards 
that morning (27th), and that, as they seemed 
like the discharge of heavy artillery, he presumed 
some man-of-war was practising with her big 
guns out of sight of land, as he could see no 
ships." Report by Mr. Elliott. 



Sounds as of firing of cannon at Trincomalee. 



The sounds were heard on the 27 th. 

'' The sounds were heard here most distinctly. They 
were like blasting on the BillhuUoya side, and 
kept on all day, from 7.30 a.m. till 4p.m." (27th). 

The sounds were heard on the 27th. 

"Loud sounds, resembling the report of distant 
cannon, were heard to the eastward on the 27th." 
Report by Mr. Fowler, Assistant Government 
Agent. 



LIEUT.-GENERAL STRACHEY ON THE SOUNDS. 



87 



Table IX. — continued. 



Place. 



Distance from 

Krakatoa, 

in English miles. 



Notes, 



Xotaimunai 



Lunngala 



1,900 (about) 



i; 



CHAGOS ISLANDS. 
Diego Chu'cia 



2,267 



BODBIGUEZ. 



2,968 



VESSELS AT SEA. 

Barque Wm, H. Besse— Oft 
Northern portion of Java. 



Ship Charles Bal 



Ship Barjild 



SS. Anerley — ^Prom the Strait 
of Banca to near the North 
Watcher Island. 

Ship (? name) — Off Lepa 
Island. 



From about 40 to 
20ea8tofE:raka- 
toa. Vessel ap* 
preaching the 
volcano. 

From aboat 11 
south to 67 N.E. 
of Krakatoa. 

About 75 east of 
Krakatoa. 

From about 250 

to 90 N.E. of 

E^rakatoa. 

About 230 N.N.E. 
of Krakatoa. 



" I heard distinctly, at about 6 p.m. on the 26th 
(local time), a loud report, as if a cannon was 
discharged down southward." Report bj Mr. 
Alfred Koch. 

Like heavy guns fired at sea in the direction of 
Hambantota on the 27th. 



" Le lundi 27 Aoiit entre 10 et 1 1 heures du matin, 
pendant le dejeuner, nous avons entendu des 
detonations sourdes mais violentes. Nous avons 
cru tellement k Tappel d*un navire en d^tresse 
oue nous avons couru et que j'ai envoye plusieurs 
homnies ve1*s le rivage exterieur de Tile sur 
plusieurs points diff^rentes, en observation. Le 
Capitaine Florentin, de VEva Joshua, et son 
second M. Daniel Sauvage, venaient de quitter 
Pointe de Test pour aller mouiller k Pointe 
Marianne, lorsqu'ils ont entendu les m^mes 
d^touations. lis ont aussitot envoy^ des hommes 
en observation k reztremit^ des mAts. Mais 
comme les miens ils n'ont rien vu." Extract from 
letter of M. Lecomte. 



^* Several times during the night of the 26th~27th 
reports were heard coming from the eastward, 
like the distant roars of heavy guns. These re- 
ports continued at intervals of between three and 
four hours, until 3 p.m. on the 27th (= 5*48 p.m. 
local time at Krakatoa), and the last two were 
heard in the direction of Oyster Bay and Port 
Mathurie." Report by Mr. James Wallis, Chief 
of Police. 

" Throughout the afternoon and night of the 26th 
we heard heavy reports, like the discharge of 
heavy artillery. At 10 a.m. on the 27th we heard 
some terrific reports." 



"The sounds were very intense, and continuous 
from 3.30 p.m., 26th, to 1.30 p.m., 27th. 



At anchor near Great Kombuis Island throughout 
the 27th. 

" Noise on the 27th resembled distant cannonading." 
" The detonations were heard all over the Ishmd 
of Banca during the 26th-27th." 

The sounds were first heard on the 26th. 



N 2 



88 



LIEUT-GENERAL STBACHEY ON THE SOUNDS. 



Table IX. — contintied. 



Place. 


Distance from 

Krskatoa, 
in Engliflh miles. 


Notes. 


Brig Airlie — LsLt 0** 30' S., 
Lon. lOS'' 54' E. 


390 


**At 3 p.m. 26th. Sonndfl like those of heavy 
artillery, which continued till about 10 p.m. 
The last report made the ship tremble all over." 


Ship Ida— Lat. 2'' 42' K, Lon. 
108° 12' E. 


622 


The sounds were heard on the 27th to the south* 
south-eastward. 


H.M.S. Magpie— Ls^t.y 52' N., 
Lon. 118^22' E. 


1,227 


"The noise of the detonations caused by Mount 
EIrakatoa, resembling distant heavy cannonading, 
was distinctly heard by us, and by the inhabitants 
of this coast as far as Banguey Island, on August 
27th." Conunander Hon. Foley C. P. Vereker, 
R.N. 


Barque Charlotte— Trom Lat. 
11" 42' S. and Lon. 107° 54' 
B., to Lat. 8* 18' S. and Lon. 
106° 42' E. 


414 to 166 • 


The sounds of the explosions were heard from 5 p.m. 
26th tiU 10 a.m. 27th. 


Brigantine Adriatio — ^Lat. 10** 
S., Lon. 106° E. 


265 


The sounds of the explosions were heard on the 
26th and 27th. 


Barque Jbnc—Lat. 4" 46' S., 
Lon. 90° E., to Lat. 7" 45' S., 
Lon. 93° E. 


1,072 to 865 


Sounds were heard on the 26th and 27th. 


Brig Catherine— Ls,t 6° 31' S., 
Lon. 86° 46' E., to Lat. 9** S., 
Lon. 87° 19' E. 


1,291 to 1,268 


The sounds were first heard on the evening of the 
26th. 


Brig Pmm— Lat. 1° 39' S., 
Lon. 92' 17' E, to Lat. 2° 59' 
S., Lon. 92° 11' E. 


944 (mean) 


" Constant peals of thunder were heard on the 26th 
and 27th in the direction of Sumatra, but with- 
out any appearance of lightning." 


Ship Lennox Ocwrf/e— Lat. 0° 0', 
Lon. 91° 23' E. 


1,060 


The sounds were heard on the 26th. 


Ship Barfcarowo— Lat. 1° 42' S., 
Lon.93M2'E.,to Lat. 2'* 36' 
S., Lon. 92° 54' E. 


900 


Sounds heard on the 27th in south-east like gnns or 
distant thunder, but no lightning visible. 



Kjvkatoa, Rep Hoy. Soc. Con\, 



Flate W. 



ENIJ^GED COPIES OF BAR0(3lAMSpR(MnGHTSEIJ;CT^ STATIONS 
SHOWING T HE CHARACTER of the first TOUR OSCIL LATIONS. 



ist 



2^ 



3^ 



Wiashuiffton. 



Toronto. 




Aberdeen, 



BomJbay, 





Zi-KcL-Wet, 





Copies of the record, of 
-were received fbr the 



another instrument 
^and4^osci2latu)ns. 




Mauritius. 



Melboume. 




South. Georgia, 



Majby & SoTUi, l.irh . 



Z^a]caZoa,.B^.B^y.SocCom. BAROMETER CURVES 

AUGT & SEPT^_1883. 



Plate Vm 




-H 



H- 



-■) + 






\. ^- ^_ 



V ! 









-f - 






I I 



.3 



v- 



--H 



--H 



- -i 
I 

- I 



TiriiLiiiiUTiL: 




^1 



rr- 



n ■ H 



-H 



irTtrntTii 



tnilTiJ 



iimu 



30^ 

II OOW 

TTTPTT 



w 



in 



tr^-^ 







^ 



j:::Li:ijnliim:it 



1 1 1 1 1 J 



1»* 

MIOT HOOK 



i-^.... 



:<n; 



. 1. 
I 



tCT IHXELTt: 



m 



UTTirr 



Wiidhin^rtan, 



Nen IbrJc 



Thn*rtto 



\Iiston 



Cohnbra 



SanRmandi* 



ThUncu'> 



\jSun\ouAi 



.Jrr.UMff): 



ffla^ffaif 



Iw^i^T>Oi>l 



'hurat 




un 



Orept^yyi 




^Mo/ife I 



\BiukLPe^ 



lodtidaK 



S^Mavhurg 



Jloavlom?k 



KaiTtbda 



Bofihc^ 



Ccd'Adti 



Zi-l w-H et 



MeSfOUTie 



^Sydney 



Tohko 



WelUn^n 



S^Oeat>ffia 



JheMark \ indicator Iht part of the tnart seiectod for Measta-ement. 



caca.Rep. Roy. Soc. Com.. 



Plate IX. 



RETDTJCED COPY OF A PORTION OF THE 
RECORD OF PRESSURE ON THE 

BATAVIA GASOMETER 

27"?^ AUGUST, 1883. 




- lEowr. 



^lOmnu \Oriffirua. ScaUs. 



Malb/ & Sons.Lith. 

Stt note, in text p. 73. 



The Scale onihe originxxL drngrairvteTnanja^ aJbthe point mxxrked. mtJh cv dotted Une. 



sr.m Rep. Roy. Soc. Com,. 



FhxieX. 



WAVEN?I. 

FIRST PASSAGE FROM 

KRAKATOA 

TO THE 

ANTIPODES 




WAVE N? II 



IL 



FIRST PASSAGE FROM 

ANTIPODES 

BACK TO 

KRAKATOA 



m 




Maib^'- <fc Sons, Lttm 



X Eep Roy. Soc. Corrt 



WAVE ]S° ni . 



Plate JU. 



SECOND PASSAGE FROM 

KRAEATOA 

TO THE 

ANTIPODES 




WAVE N«IV, 



SECOND PASSAGE FROM 

ANTIPODES 

BACK TO 

KRAKATOA 




MaJtry * Sons, Jjth 



^ccoion,R.ep. Roy. Soc. Com. 



Fixite xn. 



WAVE N^ V. 



THIRD PASSAGE FROM 

KRAEATOA 

TO THE 

ANTIPODES 




WAVE N° VI . 



THIRD PASSAGE FROM 

ANTIPODES 

BACK TO 

KRAKATOA 




Mailry & Sonr., lafh 



liatoa. Rep. Roy. Soc. Com,. 



Flatem. 



vm 



W AVEN? Vn. 

FOURTH PASSAGE FROM 

KRAKATOA 

TO THE 

ANTIPODES 



122 



/lie 



1 ^^ 


-^^x* 


«'^ 


--^^ 






1 ^ 




c:--^___^ 


120 




X i**,^- 


\ J/\ 




■/^ 


^^^^ 


j\f Ic 




\ y^/ 


"iX 


/ ^ 


---^^^^ 


/ W ^-'-"'r^ 




\ j/y^ 


/ \ r^ 




^""^^ 


/ vC'^^^ s 




\ yy'^ jt 


/ \J 




1 


\\. 




\ yy/ 






/ 


V 




\y' j^ 




/ 


\ 




^^^^ 


' \ 


\y 




^ 





^&^ 



o" 



Mallry & Soils. JAxl^ 



KfixJcaZoa,. Rep. jj 



PlateJOV. 



THE EARTH'S R0TATI0:N^. 



f 



I 



European 



j- American 

^ Australian 

\ Tropics 



CENTRAL 
LINE 




Maloy ^ Sons, JitK. 



PlaU^ M 




J 



ilaiixy £c Sons, -Lith 



KraJcatocu, R&p Roy. Soc. Com.. 



Flate,m. 



MAP SHOWING THE PLACES AT WHICH THE SOUNDS 

OF THE ZXPLOSIOTJS ■WERE HEARD ON AUGUST 26-27 
THE SHADED PORTION INDICATES APPROXIMATELY THE AREA OVER WHICH THE SOUNDS WERE HEARD. 




PART ni. 



ON THE SEISMIC SEA WAVES CAUSED BY THE ERUPTION OF 
KRAKATOA, AUGUST 26TH AND 27th, 1883. 

By Captain W. J. L. Whabton, E.N.^ F.R.S., in completion of the unfinished Notes 
of Captain Sir F. J. Evans, RN., KC.B., F.E.S. 

[In this Part Oeographical miles alone are naed.] 



On the lamented death of Sir Frederick Evans, an examination of the papers 
connected with the sea disturbance consequent upon the eruption of Krakatoa, 
on which he was at work, revealed a number of notes showing that he had made 
considerable advance with their discussion. I was requested to look at these 
unfinished notes ; and at first I came to the conclusion that a small amount of labour 
would suffice to complete them. When, however, I took upon myself to do this, I soon 
found that I had miscalculated the task, and that the notes left, though very clear, 
were but the preliminary foundation of the report ; and, moreover, that it would be 
impossible to carry it on where Sir F. Evans had left off, as many points presented 
themselves which required a thorough examination of the mass of original matter. 

Sir F. Evans had commenced to form a table of the speed of the waves, and his 
notes related principally to the selection of the crests marked on the different 
diagrams as those identical with the first arrival of the great wave from Krajtatoa. 
These I have verified, and in nearly every case have come to the same conclusion as 
Sir F. Evans. 

For the text of the report and the deductions which I have made I alone am 
responsible, as no cliie was left as to any opinion Sir F. Evans may have formed 
on the different points raised. 

The time used throughout is civil mean time in days of 24 hours, counting fi-om 
midnight. In the text, local time is referred to. For the calculation of the periods 
of translation of the waves, the time is reduced to Greenwich civil time, but this is 
given only in the tables showing the net results of the investigation. 



90 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

Accouvt of the Phenomena relating io Sea Disturbance in the immediate vicinity of 

Krakatoa. 

Mr. R. D. M. Verbeek, a Dutch mining engineer resident at Buitenzorg, a 
town situated in the interior of Java, about 30 miles south of Batavia, has collected 
all the evidence forthcoming of the details of the eruption of Krakatoa which com- 
menced on May the 20th, 1883, and culminated on August the 27th. This he has 
published in his work " Krakatau" Parts I. and II., which, accompanied by charts 
and sketches, forms a complete history of the outbreak and its effects in the 
immediate vicinity. 

As this is accessible, a comparatively brief statement of the leading proven 
or accepted facts in connection with the great sea disturbance in the immediate 
neighbourhood of the eruption will probably suffice as an introduction to the con- 
sideration of the question of its propagation to distant shores. {See also Part I.) 

During the earlier eruption in May, and up to August, no remarkable movement 
of the water was observed. The violence of the explosions recommenced diuring the 
early afternoon of the 26th of August, a particularly heavy detonation being heard 
at about 17.30 on that day. 

This was marked by the pressure gauge of the gas works at Batavia at about 
the same time; and, between 18 and 19 hours, the first large wave reached 
the Java shore at Tyringin, 24 miles from Krakatoa, where it destroyed many 
houses near the sea. At about the same time a wave caused considerable damage 
at Telok Betong, at the head of Lampong Bay in Sumatra, 44 English miles from 
Krakatoa. 

At about 19 hrs., or 19 hrs. 30 mins., the low-lying Chinese Camp at Merak was 
swept away. At Anjer this wave was only about 5 feet high. 

From this time the sea in the Strait of Sunda was much agitated, but no further 
large wave is recorded until the morning of the 27th. 

On the 27th at 1 hr. the village of Sirik, 6 miles south of Anjer, was 
submerged ; and one account mentioas a wave at Telok Betong at 1 hr. 30 mins. 

At about 6 hrs. 30 mins. a wave swept away nearly the whole of Anjer, which 
lay low, and this was followed at about 7 hrs. 30 mins. by another, which completed 
the destruction. At the same time the lower part of Telok Betong, in Sumatra, was 
overwhelmed. Two heavy air waves are recorded on the gas pressure gauge at 
Batavia at 5 hrs. 43 mins. and 6 hrs. 57 mins., which are probably connected with 
the explosions causing these waves. 

At some time a^ter 10 o'clock an immense wave inundated the whole of the 
foreshores of Java and Sumatra, bordering the Strait of Sunda, and carried away 
the remaining portions of the towns of Tjrringin, Merak, and Telok Betong, as well 
as many other hamlets and villages near the shore. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 91 

To this wave, undoubtedly the largest, must be attributed the disturbance which 
spread so far over the surface of the ocean. 

At places comparatively near and immediately exposed to the direct disturbance 
emanating from Krakatoa, no mention is made of waves after this great one, nor is 
even the great wave itself recorded. The darkness, and the fact of all the survivors 
of the 6 hrs. 30 mins. and 7 hrs. 30 mins. waves having fled from the shore, are 
sufficient to axscount for this omission. At the lighthouse at Vlakke Hoek alone, the 
great wave is said to have repeated itself three times at intervals of about half-an- 
hour. 

At one or two places outside the Strait the waves were observed to continue. 
Thus at Tjabang, about 90 miles to the north, in Sumatra, eleven waves were counted 
between 15 hours on the 27th and 6 hours on the 28th. At Batavia, the disturbance 
lasted from noon on the 27th to midnight on the 28th ; and fourteen waves, with a 
steady period, were marked on the tide gauge. As the explosions of the volcano 
•continued during the whole of the 27thj it may fairly be assumed that some other 
waves were generated subsequent to the 10 o'clock one. 

After 16 hrs. ao mins. the detonations are mentioned as gradually diminishing in 
force until 6 hours on the 28th. 

Several ships were in the Strait during the great eruption and experienced 
terrible weather, heavy squalls from different directions, confused sea, lightning, and 
a rain of mud, ashes, and pumice. None of these ships mention any particularly 
large waves, nor was any damage done by the sea. One vessel at anchor six miles 
from St. Nicholas Point, mentioned a rapid current of 10 knots an hour (estimated) 
running towards the volcano some time after the great explosion* 

It is specially worthy of remark that no earthquake shock is recorded at any 
time during the eruption, except on the evening of the 26th, when, at Anjer, the 
earth is said to have trembled. 

When the site of the eruption could be examined^ it appeared that the following 
changes had taken place : — 

Of the north part of the island of Krakatoa, an area of nearly six miles, with 
an average height of 7oO feet, had disappeared, on which the sea rolled of a depth 
not yet ascertained, but over 150 fathoms in some places. Taking the average height 
of the missing portion to be 700 feet, and the present depth at 300 feet, the mass of 
matter thus blown away may be considered as 1^ cubic miles. 

The portion of the island that remained seems to have received, according to 
Mr. YfiEBEEK, an addition of about 'one square mQe, by upheaval on the side remote 
from the portion which disappeared. This cannot be considered very certain, seeing 
that the former sm^vey by Mr. J. Richards, R.N., did not pretend to be accurate, as 
the original in the Hydrographic Department shows. 

The Peak, 2,647 feet high (Richards's Survey), had been shorn in two, leaving on 
the north face of the remaining portion a precipitous cliff of the same height 



92 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

Verlaten Island, which lay close to the north-west of Krakatoa, had a super- 
ficies of about one square mile before the eruption. It now has an area of nearly 
three miles. 

Lang Island, to the north-east, and also close to Krakatoa, was little changed, but 
had received a slight addition on its northern side. 

Two smaU new islands of mud and pumice, almost a-wash, standing on extensive 
banks, had made their appearance seven miles to the northward of Krakatoa, where 
formerly a depth of 80 feet existed. 

The depths over an area of 140 square miles around Krakatoa had undergone 
alterations; in most cases upheaval having taken place, but in some, subsidence. The 
precise amount is difficult to estimate, as the old sounduigs were in many parts 
scanty, but the general fact of change may be taken for granted, 

Eeyond this area, no alteration has yet been discovered in the depth of the sea, 
so that the movement is assumed to have been comparatively local. The first reports, 
to the effect that the whole of the Strait of Sunda had been altered, were exaggera- 
tions. 

In one part the change is very marked, and materials exist for more detailed 
statements. Between Lang Island and Sebesi, over an area of about 72 square 
miles, the depths are greatly reduced. The bank, 18 mile^ ia area, on which the two 
new islands. Steers and Calmeyer, stood, has now an average depth of 12 feet, where 
formerly it had 120 feet. Over the remainder of this area, or p,bout 59 square miles, 
the reduction in depth averages about 30 feet. The Chart^^ Nos, 1 md 2, show the 
condition of the Strait before and after the eruptiou. 

The times of arrival of the waves at different plitces on the shores of the Strait 
are but vaguely noted, and this is especially the case with the great wave after 
10 o'clock of the 27tb. Terror and dismay reigned everywhere, and darkness had 
settled over the land. At Anjer, also, where this wave must have come, no one was 
left to see it, the few survivors having fled to the hills. 

To some extent the same uncertainty attaches to the height of the waves. 
All who observed the wave after 10 o'clock, however, agree that it was the largest, 
and this is supported by all the evidence forthcoming. As this wave alone appears 
to have travelled to places at great distances, it is the most important. All observa- 
tions founded on measurements of the marks left by the water are considered as 
relating to this wave. 

The inundated portions of the shores of the Strait of Sunda are indicated on 
map, p. 17, and Mr. Yerbeek also mentions, in his account of the disaster; the 
maximum height in different localities. It is not, however, stated by whom the 
contours on Mr. Verbeek's maps were obtained, nor is the means of obtaining the 
limit reached by the water stated in every case. As far as can be gathered, the 
following were the altitudes to which the wave attained at places on each shore of 
the Strait of Sunda, and in the immediate vicinity of the volcano. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 93 

Java Shore. 

At Merak, 33 miles from Krakatoa, the height of the wave was estimated by 
Mr. McCoLL to be 135 feet ; by Mr. Nieuwenhuys, an engineer, 100 feet. It does 
not appear on what these estimates are based. The greatest height measured at which 
buildings were washed away was 47 feet. Mr. Verbeek, on his plan, shows the hill 
sides to have been washed by the water to a height of 115 feet. The peculiar 
position of Merak, standing at the head of a funnel-shaped strait formed by the 
island of Merak, may have caused the wave to be higher there than elsewhere. 

At Anjer, 26 miles from Krakatoa, the height of the wave at 6 hrs. 30 mins. is 
stated to have been over 33 feet. The subsequent and higher waves are not appraised. 

At Tyringin, 24 miles from the volcano, 50 feet is mentioned as the measured 
height of the water at one spot. As people who gained the hills at the back of the 
plain, stated to be 67 to 100 feet high, were saved, it does not appear that the wave 
could have been much over 70 feet. 

At Princes Island, 25 miles distant, the water is said to have attained a height 
of 50 feet. 

Surtiaira Shore. 

At Katimbang, 19 miles from Krakatoa, the wave is stated by Mr. Verbeek to 
have reached a mean height of 80 feet. 

At Telok Betong, the water reached within 6 feet of the top of the hill on which 
the Residence stands at a height of 78 feet, and was consequently 72 feet high. This 
seems the most accurate measurement of aU those given. The man-of-war, " Berouw^^ 
was carried 1 '8 miles inland up the valley, and left about 30 feet above the level of 
the sea. 

At the lighthouse on Vlakke Hoek the water rose 50 feet. 

From these different measurements I have assumed that the actual height of 
the wave, before it reached the shore, was about 50 feet. 

To ascertain the time of the genesis of the great wave is not, at first sight, easy, 
nor can it by any means be arrived at with certainty. 

How the wave was formed, whether by large pieces of the mass of the island 
falling into the sea ; by a sudden submarine explosion ; by the violent movement of 
the crust of the earth under the water ; or by the sudden rush of water into the 
cavity of the volcano when the side was blown out — ^must ever remain, to a great 
extent, uncertain; but more of this hereafter. What precisely took place during this 
tremendous outburst no one knows. The island was shrouded in smoke and fire, and 
was never clearly seen ; nor did any vessel approach near enough to note any changes 
in its outline during the eruption. It is, however, evident that the three larger waves 
were intimately connected with the three great explosions, for, though the testimony 

o 



94 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

of ear-witnesses is not clear on the point of the comparative force of the different 
detonations, as measured by the sound, happily the pressure gauge at the gasworks at 
Batavia, before mentioned, gives no uncertain evidence. 

This has already been referred to also in Part II., p. 69, and the record is 
reproduced in Plate IX., whence it will be seen that the three largest movements. 
Viz., those at 5 hrs. 4^ mins., 6 hrs. 57 mins., and 10 hrs. 18 mins., were all apparently 
connected with the highest three waves recorded. As far as that at 10 hrs. 18 mins. 
is concerned, there is reason to believe that the sea and air waves were formed 
practically synchronously. 

Batavia is distant 83 miles in a straight line from Krakatoa. Thus, deducting 
8 minutes for the time taken by the air wave to travel this distance, and 5^ minutes 
for the difference of longitude, the time of genesis of the air wave would be 10 hrs 
4^ mins. of Krakatoa time.* 

The tide gauge at Batavia also affords valuable evidence and an independent 
means of arriving at a time for the starting of the great wave. This automatic 
instrument has recorded the idrst great wave at 36 minutes past noon. The time 
taken, according to the formula, V=\/^, by a wave in travelling the distance 
between the two places (100 sea miles), and in the depths shown by the excellent 
chart which exists, is 2 hrs. 80 mins. Deducting this and the 5^ minutes' difference 
of longitude, we get 10 hrs. min., Krakatoa time, as the hour at which the great 
wave left the island. This I have adopted, and I find that Mr. Verbeek has come 
to the same conclusion. 

On account of the intricacy of the route, this result can be considered approxi* 
mate only, but the agreement with the other determination is sufficiently near to 
corroborate the substantial accuracy of tlie time assumed. 

In calculating the time of the propagation of the wave to Batavia, Mr. Verbeek 
has estimated the height of the volcanic wave in various sections, and calculated 

his speed for those sections, by the formula, V= a/ ^{^+€) (2 A+e), where g iB 

gravity, h the depth of water, and e the height of the crest above the normal level 

of the water. I have contented myself with the formula, V= ^gh. My result for 

the time of propagation agrees exactly with that of Mr. Verbeeb:, which is to be 

accounted for by the different routes which we have assumed the wave to take, 

among the numerous islands and shoals, and also by the different depths which we 

have calculated for the various sections ; for, though I have styled the chart excellent, 

the bottom is so uneven that any attempt to arrive at a very accurate estimate of 

mean depths can be only deceptive. 

To Anjer the wave would have taken 37 minutes, to Tyringin 30 minutes, to 

Merak 45 minutes, and to Telok Betong 61 minutes. 

* See p. 69, where General Strachey, from the discussiou of several barograph diagrams, arrives 
at a slightly diflferent conclusion. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 



95 



Assuming that waves were generated at some or all of the great explosions 
registered by the pressure gauge at the gasworks at Batavia, the following table 
shows the time of arrival of such waves at the above places on the shores of the 
Strait of Sunda. The second column gives the measure of the force of the air waves 
as registered by the pressure gauge : — 



Air wave at Batavia. ' 


Water wave 
. left 


Arrive 
at 


Arrive 
at 


Arrive 
at 


Arrive at 






ExcMs of ladi- 


Barometric 
equivalent. 


Telok 


Time. 




. catorreadinff 
above estimated 
normal. 


Krakatoa. 


Tyringin. 


Anjer. 


Merak. 


Betong. 


h. 


m. 


mm* 


in. 


h. m. 


h. m. 


h, m. 


h. m. 


h. m. 


26th— 17 


20 


13 


•08 


17 07 


17 37 


17 44 


17 52 


18 08 


27th— 1 


55 


20 


•12 


1 42 


2 12 


2 19 


2 27 


2 43 


2 


38 


21 


•12 


2 25 


2 55 


3 02 


3 10 


3 26 


4 


56 


22 


•13 


4 43 


6 13 


5 20 


5 28 


5 44 


5 


43 


41 


•24 


5 30 


6 00 


6 07 


6 15 


6 31 


6 


57 


41 


•24 


6 44 


7 14 


7 21 


7 29 


7 45 


.. 9 


42 


29 


•17 


9 29 


9 59 


10 06 


10 14 


10 30 


„ 10 


15 


63 


•37 


10 02 


10 32 


10 30 


10 47 


11 02 


„ 11 


05 


40 


•23 


10 52 


11 22 


11 29 


11 37 


11 53 



We have, however, records only of certain sea waves, which may be connected 
with some of the air waves. 
Thus— 



Air wave at Batavia. 


Sea wave at 


At 


h. m. 






26th-— 17 20 p.m. 


Tyringin. 


Between 18 and 19. 




Telok Betong. 
Merak. 


19 or 19.30. 


27tli— 1 55 a.m. 


Sirik. 


"About" 1. 


„ 5 43 „ ... ... 

„ 6 57 „ 


Anjer. 

Telok Betong. 

Anjer. 


„ 6.30. 
Between 6 and 7. 
*' About*' 7.30. 



One fact in connection with these inundations on the coasts exposed to the direct 
waves from Krakatoa is worthy of notice ; and that is, that the earlier waves, 
though of no insignificant height, were partial. Thus, the wave between 18 hrs. and 
19 hrs. of the evening of the 26th was scarcely noticed at Anjer, although on the same 
shore, to the north and south, considerable damage was done. The village of Sirik, 
only 6 miles from Anjer, was destroyed at 1 hr. on the 27th ; but this wave is not 
mentioned at any other place. 

Krakatoa stands in the centre of the Strait of Sunda, the shores of which form 

a rough elongated semi-ellipse. The outward, or western, portion of the ellipse being 

absent, permits free outlet for waves in that direction into the Indian Ocean. The 

eastern smaller end of the ellipse also is missing ; and permits waves to travel in that 

direction through a passage 12 miles in width. 

o 2 



96 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

To the west, the water is clear and deepens regularly to the Indian Ocean ; as 
far as the imperfect nature of the survey admits of estimation. 

To the east, the water is comparatively shallow : a large island blocks the 
already narrow channel, reducing it to 9 1 miles, which opens into the stiU shallower 
Java Sea, encumbered with reefs and shoals, and hemmed around by the far extending 
islands of the Eastern Archipelago. 

To the west, therefore, the waves from Erakatoa, which we have seen were 
probably 50 feet in height on leaving the island, have freely spread. To the east, 
friction among the shoals has rapidly reduced them ; so that their extension in that 
direction has been comparatively small. 

The indications of the tide gauge of the harbour of Tanjong Priok at Batavia 
are most valuable, as giving the nearest and most unmistakable record of the 
Krakatoa waves, A glance at the diagram will show the character of the dis- 
turbance. 

From 20 hrs. of the 26th, the curve begins to show signs of oscillations of level, 
which are, however, small until noon of the 27th, not averaging more than 3 inches. 
Notwithstanding, waves may be traced corresponding to the explosions of 1 hr. 
42 mins., 2 hrs. 25 mins., and 5 hrs. 30 mins. of the 27th, of which the best marked is 
that corresponding to the 5 hrs. 30 mins. explosion, which aiTived at Batavia at 
8 hrs. 20 mins. 

At 11 hrs. 30 mins. the water began quickly to rise ; and at 12 hrs. 15 mins. a 
perpendicular line shows that the final rise was almost a wall of water, as the first 
great wave arrived and inundated the shore. This attained a height of 7^ feet above 
water level at the time, at 12 hrs. 36 mins. It then fell as rapidly to 10 feet below 
the level. These measurements are those given by Mr. Verbeek, who states that 
the gauge would not register the full range of the wave. The diagram shows only 
+ 1*60 m., and — 0*23 m„ but Mr. Vebbebk states that the measurement for high 
level was taken on the stones of the pier as + 2*35 m. 

That for low level he gives as — 3*15 m. The gauge would register — 1*10 m. ; 
but Mr. Yebbeek gives as his explanation of the lower minimum which he adopts, that 
the water had already begun to rise under the influence of the second wave, before 
the level could fall below — 0*23 m. It is not easy to understand, if this was so, 
how the water could have been noted at — 3*15 m., and the shape of the curve does 
not give any justification for the assumption. He does not say how the observations 
for the minimum were taken, beyond the statement that they were made to fixed 
points in the port. This figure therefore for the minimum appears doubtful, and I 
am inclined to think that the range of this first wave cannot be considered as 
very exact, and is probably under the amount given by Mr, VEltB]BEK, which is 
18 feet. 

The second wave als9 was above the highest point the gauge would mark, and 
may be taken as Mr. Verbeek gives it, 1'95 m. This wave attained its maximum at 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 97 

14 hrs. 48 mins., or 2 hra. 12 mins. after the first. Its crest was therefore 80 miles 
distant when the first wave arrived. 

It is to be remarked that at Batavia the first phenomenon was a rise unpreceded 
by any faU of level, which appears to indicate that the wave leaving Krakatoa was 
a positive one. 

The first wave is followed by waves of gradually diminishing height, 14 of which 
are at tolerably regular intervals, and give a mean period of 2 hrs. 02 mins. from crest 
to crest. These are : — 

h. m. h. m. h. m. H. m. h. m. lu m. h. m. 

Times .. 12 36 14 48 16 43 18 58 20 25 22 20 40 

b. m. li. m. H. m. h. in. h. m. h. m. h, m. 

Intervals.. 2 12 1 55 2 15 1 27 1 55 2 20 2 30 

Height in feet* 6^ i^ If 1^ i 1^ 1 

b. m. h. m. b. m. b. m. b. m. b. m. b. m. b. nu 

Times .. 3 10 5 10 7 20 9 10 11 00 13 10 14 55 17 05 

b* m* b* in* b» m* b. m. b. m. b. m. b. nu 

Intervals ,. 2 00 2 10 1 50 1 50 2 10 1 45 2 10 

Height in inches 91194 4 2 3 3 

This period of 2 hrs. 02 mins. is very reiTiarkable if the circumstances are con- 
sidered. If the wave was caused by any sudden displacement of the water, as by 
the falling of large masses of ejected m^^tter, and huge fragments of the missing 
portions of Krakatoa, or by the violent rush of st§am from a submarine vent through 
the water, it is hardly to be conceived that two hours would elapse before the 
following wave, the second of the series, started after it. 

K the supposition that the wave was caused by the opening of a great chasm in 
the earth, by the bursting of the si4es of the hollowed Krakatoa, into which the sea 
rushed, cpuld be inaintained, a wave of long period might also be explained ; but, 
though some such inrush must have occurred when the water flowed over the site of 
the island, to set up a long wave, as is now recjuired, two things appear necessary : 

First, — that the chasm was large enough to permit water to flow into it con. 
tinuously for an hour at a rate sufficiently rapid to cause a great lowering of the 
water level in the vicinity of the island, in prder to set up a wave. 

Secondly, — that the first effect reaching the shore was a negative wave. 

Now, the first supposition is so improbable that it certainly requires evidence 
before it can be adopted ; and the second is contrary to the record of the Batavi^ 
gauge, which shows a distinct positive wave as the earliest phenomenon. 

If, however, upheaval of the bottom of the sea, more or less gradual, and lasting 

^ These heights are, as all others of waves in this Part, measured from the normal level ot the 
water At the time, as deduced from the tidal diagrams. 



98 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

for about an hour, took place, we should have a steady long wave flowing away from 
the upheaved area, which as it approached the shore would be pUed up considerably 
above its normal height. Thus these waves of long period would be set up ; and 
this would also account for the rapid current recorded by the ship " William H. 
Besse/' which is described as 10 miles an hour, though probably that is au 
exaggeration. The water would flow back on the motion ceasing. 

If we now turn to the condition of the area round Erakatoa and compare it 
with the previous state of things, we find that, as summarized at page 92, upheaval 
has taken place over a large surface. Two entire islands have appeared where 
formerly the water was deep. Verlaten Island has been increased by two square 
mQes, and extensive banks have been raised. 

I should have been inclined to consider this as the sole caiise of the great waves, 
more especially as it would entirely explain the somewhat remarkable &Lct that ships 
not far from the volcano at the time the wave was travelling from it, felt nothing of 
the stupendous undulation which rushed so far up the slopes of the hills. 

We find, however, as wQl be seen when the eye observations at distant places 
are Considered, that, besides the waves of long period, which after travelling 
thousands of miles were not of sufficient height to attract much notice, waves were 
observed by eye-witnesses following one another at rapid intervals of from five to 
fifteen minutes, and of heights of from two to three feet, though, from their short 
duration, they were not marked upon the gauges. 

These seem to demand another cause, and it appears to me that they may be due 
to the large masses of the island blown away by the force of the explosions and 
falling into the sea, or, possibly, to the sudden displacement of the water over a 
submarine vent. 

The missing mass of Ki*akatoa may be roughly estimated to be at least two hundred 
thousand million cubic feet (200,000,000,000). A fiftieth part of this mass dropping 
suddenly into the water would, by its displacement alone, furnish sufficient liquid to 
form a wave circle of 100 miles in circumference, 20 feet high, and 350 feet wide. 
The surrounding islands and shoals would, however, prevent a perfect circle being 
formed, and the wave might therefore be concentrated on certain parts of the arc, and 
be at some places higher than at others, varying according to the direction in which 
the masses fell. It has been remarked that this partiality of the waves was noticed. 

I incline then to the opinion that the destructive waves in the Strait of Sunda 
were mainly due to these masses falling into the sea, or to sudden explosions under 
the sea after it flowed freely over portions of the former site of the island, possibly to 
both causes ; but that the long wave which was recorded on so many tide gauges had 
its origin in upheaval of the bottom. 

It does not appear unreasonable to assume that at tha time of the great 
explosion of 10 o'clock, waves of both characters would be more or less synchronously 
formed. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 



99 



I advance this hypothesis of the origin of the waves with some diffidence, but 
it appears to me not improbable from the known facts, and it would explain away 
some difficulties. 

I cannot find any accurate observations bearing on the subject of the descriptions 
and heights of waves originating from a violent displacement of water on a large 
scale. 

Two explosions have recently (October, 1886) taken place at Spithead. The 
first of 6,000 lbs. of gun-cotton in 10 fathoms water occurred on a very calm day. 
Ujafortunately I knew nothing of it beforehand, and no one was on the look out for 
waves. Two officers, however, standing on the beach 4^ miles distant, noticed a wave 
approaching, and estimated its height at about two feet. It was followed by others at 
short intervals, but the number was not noted. 

The tide gauge in Portsmouth Harbour, a very delicate instrument by Sir 
William Thomson, showed on its diagram no disturbance. The distance is 4 miles, 
but shoals and a narrow channel intervene, which possibly killed the wave, otherwise 
this failure to mark the wave might be taken as evidence that these short waves did 
not afiect the gauge. 

The second explosion of six mines of 500 lbs. of gun-cotton each, 45 feet below 
the surface in 60 feet of water, took place on 5th November, 1886. The mines were 
laid in a line about 100 feet apart. The day was stormy, and the- surface of the sea 
much troubled. 

The explosion threw up a wall of water extending a^long the line of mines, and 
estimated to be 150 feet high. 

Only one observer on shore recorded any waves. He had provided himself with 
a small tube, in which a float carrying a light rod worked. The float worked 
incessantly from the action of the short wind waves, but he noticed that the whole 
body of the surface was raised at regular intervals. As his float hung at a certain 
point when falling, he was not able to register the depressions by it, but the observa- 
tions for the crests were as follows : — 



Explosion at 
Crest at 



h. 


m. 


• 8, 




15 


35 




20 


20 




22 


30 




25 


00 




27 


45 




29 


45 




31 


30 




34 


00 



Interyals. 


m.' 


0. 


4 


45 


2 


10 


2 


30 


2 


45 


2 


oo: 


1 


45 


2 


30 



The height fix)m crest to trough he estimates at one foot. 

The first wave arrived at 4 mins. 45 sees, after the explosion, the site of which 



100 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 



was 1-j^ miles distant. The intervening mean depth is 6 fathoms. Theory gives a 
time of 4 mins. 12 sees, to traverse this distance. 

It is to be remarked that the observer had no pre-conceived ideas as to the time 
the wave should arrive. His observations are therefore quite independent. He 
reports that the first phenomenon was a fall in the surface immediately followed by 
the first crest. 



Genebal Account of Data available, and the Mode of theib Discussion. 

To follow the movements of the wave which spread to distant shores, we have 
the indications of self-registering tide gauges and eye observations. The former only 
can be considered as accurate, but in some cases the latter give fair results* The 
tidal diagrams available are as follows : — 



To the west of Exakatoa — 
Andaman Islands 



East coast of Hindostan 



In River Hoogly • . 

West coast of Hindostan 

South coast of Arabia • • 

South coast of Africa . . 

South Georgia Island . . 

Tierra del Fuegp 

East coast Central America 

West coast of France • . 
North coast of France , . 



South coast of England. . 



Port Blair. 
T^egapatam. 

Madras. 

Vizagapatam. 

False Point. 
^ Dublat. 
f Diamond Harbour. 
I Kidderpore 

{Beypore. 
Bombay. 
KarachL 
Aden, 
r Port Alfred. 
. . i Port Elizabeth, 
I Table Bay. 
Moltke Harbour. 
Orange Bay. 
Colon. 
rSocoa. 
L Rochefort. 

{Cherbourg. 
Havre. 
. Devonport. 
Portland. 
Portsmouth. 
^ Dover. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 
To the east of Krakatoa — 



101 



North and East coasts of Java. . ^ 

South coast of Australia 

New Zealand 

Ed^t coast of Australia . . 
Sandwich Islands 
xxjasisLa • • • • • • 

West coast of North America 



Batavia (Tandjong Priok). 

Ujong Pangka. 

Sourabaya. 

Karang Kleta. 
rPort Adelaide. 
LWilliamstown. 
r Port Lyttelton. 
L Dunedin. 

Sydney. 

Honolulu. 

St. Paul's, Kodiak. 

Saucelito, San Francisco. 



Of eye observations, we have reports to the west of Krakatoa from — 



West coast of Sumatra . . 
South-west coast of Ceylon 

East coast of Ceylon 

Seychelles Islands 
Cargados Garajos 
Rodriguez Island 
Mauritius 

To the east of Krakatoa, from — 
West coast of Australia 
New Zealand •• 



Padang. 
rCalle. 
' L Colombo. 
f Arugam. 

Batticaloa. 

Trincomalee. 

Mullaittivu. 
t Point Pedro. 

Mah^. 

Avocaire Island 

Mathurin Bay. 

Port Louis. 



r Cossack. 
LGeraldton. 
Various places. 



Throughout this paper the following is the sense of diflferent terms : — 

The height of the wave is the height of the crest above the normal level of the 

water at the time. 
The range of the wave is the vertical distance from crest to trough. 
The length or amplitude of the wave is the distance in geographical miles from 

crest to crest. 

The original diagrams from the automatic gauges are on every conceivable scale, 
for both height and time. Some are kept in civil, some in astronomical, time ; some 



102 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

record the height in mHres, some in feet ; some work from left to right, others in the 
opposite direction. 

The copies accompanying this paper are reduced to one uniform scale, convenient 
for publication, of ^ of an inch to a foot, and ^ of an inch to the hour, except the 
curves for Socoa, Rochefort, Cherbourg, and Havre, which are on a larger scale, so 
that the minute fluctuations may remain visible. These show the heights in feet, at 
local civil time, counting from midnight to 24 hours. (See Plates XVII. to XXXV., 
p. 150.) 

In calculating the time of translation in the tables I have reduced all the times 
to Greenwich civil time ; but in speaking of the waves, I mention the local tima 

The indications of the arrival of the wave on these diagrams are by no means 
always precise ; and the variety in the appearance of the diagrams is very marked. 
In all cases they show long continued disturbance ; but the complication of the waves 
in some is as remarkable as the regularity of the series is in others. In all cases the 
more prominent waves are, unlike those registered at Batavia, preceded by minor 
oscillations, which in some instances merge so insensibly into the higher waves that it 
is difl&cult to identify any one wave as the first of what may be called by comparison 
the greater disturbance. 

Seeing that several large waves reached the shores of Sunda Strait before the 
great one of 10 o'clock, it would not be surprising to find that these earlier waves 
occur on the diagrams, were it not for the very slight indications of them marked on 
the Batavia gauge. The path, however, to the westward is so much more open that 
these possibly shorter waves found their way across the Indian Ocean, while they 
were killed by the sudden expansion into the Java Sea. 

On the east coast of India the arrival of the greater disturbance is unmis- 
takable ; which is probably due to the shorter distance and the unimpeded course of 
the waves in deep water. Here also there appears to be but one series of the larger 
waves for at least some hours ; but at places further removed, several series of long 
waves can be made out, which much interfere with the regularity of the diagrams. 

The position of some of the gauges, inside bars, up rivers, and in similar places 
not open to free access from the sea, may have had some effect on the appearance of 
the diagrams. 

Another cause of variety is the difference in the construction of the gauges. 
When the orifices in the tube which admit the water are too large, local waves appear 
to affect the record. 

Assuming fi-om the well-marked character of the waves shown on the Batavia 
diagram that the period of the waves that left Krakatoa was about 2 hours, I have, in 
my investigation of the diagrams, first examined them to see whether the same period 
can be identified. In this I have met with imperfect success. Though in many cases 
such a period can be found, it is fi-equently only to be arrived at by taking every 
alternate wave, the intermediate ones being nearly half-way between those selected. It 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 103 

thus appears either as if the original waves had in their long course divided and 
doubled themselves, or as if the great wave reflected from the eastern shores of the 
land bounding the Strait of Sunda was the cause of the intermediate waves, the 
distance of these shores being such as would cause the time elapsing between the 
primary and reflected waves to be roughly a moiety of the long period of 122 minutes 
recorded at Batavia. 

At the very distant stations, as Orange Bay, and the ports of the English 
Channel, the wave period is, in some instances, roughly one-fourth of the original 
period of Batavia ; which looks like a still further sub-division of the waves ; but 
there are exceptions. 

In all cases I have taken the first of a recognisable series of higher waves as 
being identical with the great 10 o'clock wave from Krakatoa, though generally the 
maximum wave follows at a longer or a shorter interval. 

The speeds that are tbus deduced should be, therefore, those of the great wave ; 
the previous undulations, though sometimes — as far as height is concerned — ^merging 
somewhat insensibly into the accepted waves, not agreeing with them in period. 
The speed, moreover, that would correspond with these earlier waves in most of the 
diagrams would be so high as to place them beyond the bounds of probability. 

I have given the speed calculated from the formula V = v^ grA, and the corre- 
sponding depth in fathoms of the water over which the wave has travelled, as well 
as the probable mean depth from the known soundings on the line. 

A direct comparison can thus be made between the theory and the known facts ; 
and although the soundings obtained are in some cases scanty, and in others altogether 
wanting, it will be seen that in such instances where material exists, the comparison 
is always to show that the wave has travelled at a slower velocity than theory 
demands. Against this conclusion must be stated the consideration that any unknown 
ridges would diminish the speed ; but these must be large, or the portion of the wave 
overlapping them would still travel at the speed due to deeper water, and over a very 
slightly longer course. 

It will be seen that the first great wave is sometimes preceded by a considerable 
fall, or negative wave. From the fact of the Batavia gauge showing as the first 
indication an unmistakable sharp rise, I conclude that the original disturbance 
propagated from Krakatoa was a positive wave, and that this depression is merely due 
to the fact of smaller waves preceding the greater disturbance, whatever may have 
been the reason of their existence. 

In the discussion of each diagram, I have given the period of the series of waves, 
both of those which seem to correspond with the two-hour period, and of the shorter 
series of which these are made up. 

I have presented in a tabular foi-m the main results of the investigation into the 
time of translation of the distiurbance. 

To arrive at the most probably accurate estimate of the velocity of the wave 

P 2 



104 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

between Krakatoa and the different places^ I have taken from the large scale charts 
of each harbour and coast, when sufficient data are forthcoming, the distances over 
which, in approaching the tide gauge, the wave would have to travel in shallow water, 
that is, water under 1,000 fathoms. 

For these distances I have calculated the time which the wave would occupy in 
traversing them, according to the depths, by the formula V= "^'gh^ and subtracting 
this time and distance from the total, the remainder will give the time taken by the 
wave in crossing the deeper intervening space. This gives a better means of judging 
whether the disturbance can be considered truly to have emanated from the volcano, 
as the smaller depths, in which the change of velocity is most rapid, are thereby 
eliminated. 

Unfortunately, in many instances the soundings are not carried far enough from 
the shore to show where the 1,000 fathom line is. 

In one of the columns in the table I give the outermost soundings available. 

It is to be regretted that at the outset, from Krakatoa itself, the soundings are so 
sparse that it cannot be determined with any exactitude where the 1,000 fathom 
depths begin, but I have taken it as 50 miles from the island, and have, from the few 
depths given, calculated 16 minutes as the probable time when the wave would reach 
this depth, and henceforth travel in deeper water over the Indian Ocean. I have 
therefore subtracted this 50 miles and these 16 minutes from the distances and times 
of every wave leaving Krakatoa by the west. 

The distances have been in all cases taken as the shortest, i.e., have been 
measured on a great circle, or on several arcs of great circles, when land, islands, or 
banks intervene. 

Though Sir G. Airy, in his article in the ' EncyclopsBdia Metropolitana,' states that 
it is only when the amplitude of the wave is one thousand times the depth of the 
water that the simplified form V = *y gh of his general equation can be taken as 
accurate ; the difference between the depths thus calculated and those by the more 
nearly exact equation, is so small, when dealing with these waves which appear to 
have an amplitude of over one hundred times the depth, that, considering the 
inexactness of the times and the doubt as to the identification of the right wave, I 
have used the simpler form. 

To the eastward of Krakatoa, or into the Java Sea, the wave does not appear to 
have been noticed at any great distance. Thanks to the tide gauges, three in number 
— erected in the Strait of Sourabaya — indications of its presence there exist ; but 
its maximum height is only 10 inches, too insignificant a disturbance to be otherwise 
noticed. 

We do not find that it was observed beyond Sourabaya, which is 440 miles from 
Krakatoa. 

To the great and sudden expansion of the area in which the wave would find itself 
on emerging from the narrow portion of the Strait of Sunda, north of Merak ; to the 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 105 

general shallowness of the Java Sea ; and to the interposition of banks and islands, is 
doubtless due this small extension of the disturbance to the east and north. 

The automatic tide gauge at Singapore showed no disturbance, nor was anything 
remarked at Hong Kong. 

The wave at Merak was, say, actually 50 feet high, having travelled over an 
average depth of 29 fathoms for 34 miles. 

Up to this point, however, the sea is open, and no interference by reflection or 
otherwise would take place ; but a gradual closing of the passage towards the end 
would probably tend to raise its height. 

Immediately, however, after passing the strait, 10 miles wide, on one side of 
which Merak is situated, the height of the wave must have rapidly diminished on its 
expansion in the Java Sea. Thus we find at the North Watcher, a small island in 
the open sea, 53 miles beyond Merak, and 82 miles from Krakatoa, that its height 
was reduced to 8 feet, as reported by the lighthouse keepers in the island. The 
average depth over which the wave would travel from Krakatoa to the North Watcher 
is 22 fathoms, the course being nearly in a straight line. At Dindang, 240 miles 
from Krakatoa, the wave was 4^ feet high, having travelled in a straight line over 
an average depth of 16 fathoms. The same is found in the other direction jfrom 
Krakatoa. At Vlakke Hoek Lighthouse, 54 miles in a straight line from Krakatoa, 
the water rose 50 feet ; but at Benkunat, 36 miles further — ^but round the corner — ^it 
was barely noticed. 

Table I. gives the statistics for the places near Krakatoa, and Plate XXXIV. 
will show their positions better than any description. The height of waves must, 
however, be regarded as only approximate, as they are all from eye observations 
and reports only. 



106 



CAPTAIN WHAETON ON THE SEISMIC SEA WAVES. 



TABLE I. 
Showing height of wave in the immediate vicinity of Sunda Strait. 



Time 

from 

Krakatoa. 



o 



-3. 

OQ 






I 



I 



I 

o 
OQ 



^Tyringin 

Anjer 

Merak 

Kalianda • • 

Telok Betong 
^Vlakke Hoek 

North Watcher Id 

Tjabang 
Dindang 

'Bantam 



Lontar 
Kramat 
Batavia (T. Prick) 
TjilintiDg . . 
Tji Lamaja 
Bambatan . . 
Japara 

Ujong PaDgka 

^Winkoops Bay 

Tyliatiap • . 

Benkunat . . 



Kro6 
Sambat 
Manna 
Pino. . 

Bencoolen . . 
Moeko-Moeko 
Painan 
^Padang 



2 
2 

4 

6 

8 

10 



00 



30 



30 



30 
30 
30 
00 
00 
32 



00 



Distance 
in 
sea or 
geogra- 
phical 
miles.* 



46 



24 
26 
33 
27 
38 
54 
82 

95 

240 

50 



55 
77 
100 
102 
145 
184 
310 
440 
147 
330 
90 

130 
160 
210 
215 
265 
370 
455 
490 



Ayerage 
depth in 
fathoms. 



29 
31 
29 
21 
17 
100 
22 

17 
16 

26 



27 

28 

28 

25 

22 

17 

26 
200 
200? 
300? 

300? 
350? 
350? 
350? 
300? 
300? 

? 

? 



Height 
of wave 
in feet. 



50? 
50? 
50? 
50? 
50? 
50? 
8 

4 



n 
11 

6 
2 



5 

6 
very- 
slight, 
none. 

6 

8 

7 

3 

4 

9 



Situation as regards free access 
for wave. 



In open sea in straight line from 

Krakatoa. 
Open, but I'eefs. 
Open, bnt reefs, in stright line from 

Krakatoa. 
Only 15 miles round the peninsula of 

Merak, where the wave was 50 

feet. 
Open. 
Open. 

Open, but many reefs. 
Close to east of Batavia, but protected. 
Open bay, but screened to west. 
Open. 
Open. 
Open. 
Open. 

Fairly open. 
30 milesroundcomerof Ylakke Hoek. 

60 milesroundcomerof YlakkeHock. 

Open to wave. 

Bay protected from direction of wave. 

5 miles from Mann&, bnt exposed. 

Protected by reefs. 

Open to wave. 

Bottom of bay open to wave. 

Open to wave, but many reefs. 



* An average geographical or sea mile is 2,025 yards, or about 1 * 15 English mile. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 107 

TIDAL DIAGRAMS. 



JAVA. 

There are three automatic tide gauges east of Batavia, all in the island 
of Java. 

Ujong Pangha. 

This is on the north coast of Java, 340 miles east of Batavia. The tide gauge 
shows disturbaDce of an irregular character, in which no period can be recognised. 
A small wave occurs at 17 hrs. 45 mins., but a decided rise is shown at 21 hours, 
which I take to be the great wave. Its height is about 9 inches. This time will 
give a velocity of 42 miles an hour, which agrees almost exactly with that deduced 
from the formula V = ^yh. The depths from off Batavia, up to which spot the 
track of the waves to the two places is identical, average about 25 fathoms, but 
vary considerably. The disturbance lasts 19 hours. 

It is rather astonishing that the regular waves which are registered at Batavia 
should have entirely disappeared by the time the disturbance reached this gauge. 
The long extent of shallow water and the strong currents which frequently prevail 
off this coast may account for the breaking up of the regularity. 

Ujong Sourahaya, 

This gauge is placed on a point half-way through the narrow and shallow strait 
of Sourabaya. The disturbance is as slight and irregular as at Ujong Pangka, and I 
take the first distinct wave crest at 22 hrs. 25 mins. for comparison. 

The distance from Ujong Pangka, which stands at the entrance of the strait, is 
25 miles, with an average depth of i^ fathoms. 

This should require 1 hr. 36 mins. to traverse, whereas the time registered is 
1 hr. 24 mins. — a very close agreement when the circumstances of the channel 
are considered. 

Karang Kleta. 

This gauge is on a small rock at the southern end of Sourabaya Strait. The 
disturbance is again irregular, but bears a marked resemblance to Sourabaya, from 
which it is distant 14 miles, with an average depth of 4 fathoms. The wave which 
corresponds to that at Sourabaya is, however, registered 25 minutes earlier than at 
that place, which makes it to have travelled over the strait from Ujong Pangka in an 
hour, instead of 2 hrs. 27 mins., which is given by theory. Tliis discrepancy is not 
easy to explain. 



108 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

INDIA. 

The report furnished in December, 1883, by Major Baird, R.E., in charge of the 
tidal survey of India, has been already communicated to the Royal Society.* 

The account of the disturbance at each tidal station in India, as taken from the 
original diagrams, is given in great detail, and all the interesting points are discussed 
by Major Baird. His report also contains statements of the phenomena noticed at 
other places where no gauge was at work. 

We now possess much fuller information on many of the occurrences external 
to India than was available when Major Baird wrote his paper; and, with the 
consent of the Committee, I do not purpose to reproduce the paper, as it would be 
difficult, without destroying its connected character, to remove those portions 
which are founded on insuflSicient data. 

I have re-discussed the data furnished by the Indian gauges from a somewhat 
different point of view from that adopted by Major Baird, founding my selection of 
waves on the small-scale diagrams ftirnished by him, and checking the times of 
arrival of the waves by his detailed account, taken from the originals as given in 
his paper. 

Port Blair. 

This bay in the Andaman Islands, 1,480 miles from Krakatoa, is the nearest 
place furnished with a gauge to the west of the Strait. 

From 3 hours of the 27 th a very small oscillation is shown, which increases at 
noon ; and at 13 hrs. 55 mins. a very distinct wave, with a height of 7 inches, appears. 

This is the first of a long series given below — 

h. m. h. m. h. m. ' h. m. h. m. h. m. 

Times .. 13 55 14 53 16 03 17 09 18 05 19 14 



Intervals . . 


m. m. m. m. 

58 70 66 56 


m. 

69 


m. 

48 


Times 


20 02 21 12 22 35 23 15 


12 


1 20 


Intervals . . 


70 83 40 57 


68 


55 


Times 


2 15 3 15 4 30 5 30 


6 40 


7 35 


Intervals . . 


60 75 60 70 


55 





The double intervals are — 

128 122 117 153 97 123 135 130 minutes. 

This gives' a. mean interval of 62 minutes, or, for every other wave, of 2 hrs. 
06 mins. — ^nearly the Batavia interval. 

Taking the 13 hrs. 55 mins. wave for comparison, the velocity for the distance 
of 1,480 miles is 308 miles an hour from shore to shore. Unfortunately, in this case, 

• * Proc. Roy. Soc.,' vol. xxxvi., pp. 248-253. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 109 

no data exist for eliminating the wave near the Andaman shore, but the wave has 
probably travelled at about 320 miles an hour, which would give a mean depth 
of over 1,500 fathoms. 

Negapatam. 

The position of this gauge is just inside the bar of the river, but the coast is 
straight and open. The diagram shows, as at Port Blair, a small oscillation from 
midnight to 13 hours of the 27th, when a distinct wave of 9 inches in height is 
registered as the first of a series of eleven waves, of a mean period of 68 minutes, or, 
taking every alternate wave, 2 hrs. 10 mins., which again is not very different from 
Batavia« 



Times 


h. m. u. m. h. m. n. in. h. m. h. in. 

14 40 16 05 16 48 17 50 18 52 19 43 


Intervals . • 


in. xn. xn. m. m. m. 

85 43 62 62 51 67 


Times 


20 50 21 50 23 09 24 00 1 32 3 10 


Intervals .. 


60 79 51 92 98 


The double intervals are — 




128 124 118 139 143 minutes. 



The distance is 1,805 miles between the 1,000 fathom depth off the Sunda 
Strait and 150 fathoms off Negapatam, the known soundings not extending to deeper 
water. This, taking the 14 hrs. 40 mins. wave, gives a velocity of 357 miles an hour, 
which corresponds to a mean depth of 1,880 fathoms. 

Arselar River ^ Karihah 

At this port, 10 miles north of Negapatam, there is no self-registering tide gauge, 
but the attention of the Port Officer was called to the movement of the water. 

He reports that at 2 o'clock in the morning of the 27th, a small disturbance was 
visible in the river, which continued all the morning. After 1 1 o'clock the waves 
succeeded one another with greater rapidity, and with gradually increasing height. 
Between 13 hours and 15 hours they were of about 22 inches range, with a mean 
interval of about 45 minutes. From 4 o'clock they began to diminish, disappearing 
entirely by 11 hours of the 28 th. 

The maximum height here corresponds with the record of the diagram at 
Negapatam, though the mean interval mentioned is less, 45 minutes instead of 68. 
This is the ' only case on the coast of India, in which eye observations can be 
compared with a diagram at no great distance. As far as height goes they agree, 
nor does the interval differ so much as do those of the waves observed in Ceylon. 

The only waves, therefore, noted here appear to be of a similar character to those 
recorded on the gauges. 

Q 



no CAPTAIN WHABTON ON THE SEISMIC SEA WAVES. 

Madiras. 

This gauge is situated inside the artificial port, and is fitted with very small 
inlet holes at the bottom of the tube, the local swell being ordinarily great. The 
diagram is in consequence very smooth, and exhibits quite a different appearance from 
the majority of the others. The disturbance begins abruptly at 14 hrs- 33 mius. on 
the 27th, the first of a series of ten waves with very irregular periods, the mean of 
which is 87 minutes. This is quite different from the period of the other gauges, and 
is rather incomprehensible. 



Times 


h. m. h. m. h. m. h. m. h. m. h. m. 

14 33 16 27 17 48 19 33 21 00 22 20 


Intervals . . 


m. n* in. m. in. in. 

114 81 105 87 80 67 


Times 


23 27 40 2 30 3 54 5 07 


Intervals .. 


73 110 84 73 



The distance is 1,863 miles from the 1,000 fathom line off Sunda Strait to the 
100 fathom line off Madras ; and taking the 14 hrs. 33 mins. wave, the velocity 
comes out 338 miles an hour, which gives a mean depth of 1,700 fathoms. 

Vizagapatam. 

This diagram is remarkable for the large number of small oscillations shown 
throughout. These are in all .probability due to the construction of the orifices 
admitting the water to the tube, which permits waves of short period, whether local 
or subsidiary to the seismic disturbance, to be registered. The result is to much 
confuse the record. The first appearance of the larger waves on the diagram bears a 
strong resemblance to those at Port Blair, but afterwards they lose their individuality 
and it is difficult to recognise them. The first large wave of 6 inches in height is at 
15 hrs. 14 min., and eight other waves may be selected with a mean period of 
77 minutes, or a period for the double waves of 2 hrs. 34 mins. 

h. m. h. m. h. m. h. m. h. m. h. in. h. m. li. m. h. m. 

Times.. 15 14 16 33 17 33 19 03 20 28 2145 22 55 10 130 

m. in. m. m. m. m. m. m. 

Intervals 79 60 90 85 77 70 75 80 

The double intervals are — 

h. in. h. m. h. m. h. m. 

2 19 2 55 2 27 2 35 

It is useless to try to follow the waves further, though the disturbance lasts to 
21 hours on the 28th, or for 30 hours. The 15 hrs. 14 mins. wave gives a velocity ot 
338 miles an hour for the distance of 1,909 miles, measured from the 1,000 fiithom 
line off Sunda Strait to the 100 fathom line off Vizagapatam. 



CAPTAIN WHABTON ON THE SEISMIC SEA WAVES. Ill 

False Point. 

This gauge is situated in shallow water on the inshore side of a long sandy spit, 
which projects parallel to the main line of coast, and the wave has to travel over a 
long distance in shallow water before it reaches the gauge. The outermost sounding 
is 23 fathoms, and the bank probably extends much further to seaward. 

The diagram is remarkably free from short waves of all kinds, and the only 
ones r^pstered are those of a mean period of 2 hrs. 42 mins., of which six can be 
traced. 

k. m. h. m. h. m. h. rxu h. in. h. m. 

Times .. 16 36 19 30 22 15 1 05 3 20 6 05 

h. in. n. m. h. m. li. m. lu m. 

Intervals .. 2 54 2 45 2 50 2 15 2 45 

The height of the largest wave, the second, is 14 inches, which much exceeds 
that at any of the other Indian stations. This is probably due to the long extent 
of very shallow water. 

The 16 hrs. 36 mins. wave gives a velocity of 808 miles an hour for the distance 
of 2,003 miles, measured from the 1,000 fathom line off Sunda Strait to the 
23 fathoms off False Point. This corresponds to a mean depth of 1,400 fathoms ; 
but if the extent of the bank off False Point were known, this mean depth for the 
ocean course would probably be indicated as considerably greater. 

Ihiblat, 

This gauge, at the entrance to the River Hoogly, is situated in a position fairly 
open to the sea, but the coast is faced with wide banks over which the waves must 



The diagram is free from short undtilations, which much fistcilitates the recogni- 
tion of individual large waves. 

Twelve waves of a mean period of 65 minutes, commenoing with a well marked 
one of 8 inches at 17 hrs. 56 mins., can be followed. The period of the double 
waves is 2 hrs, 7 mins., which brings us back to the Batavia period again. 



Times .. 17 56 18 


in. 

50 


li. in. h. m. n. m. n.> m* 

19 52 21 00 21 55 22 57 


m. 

Intervals . • 54 




m. m. nu m. m. 

62 68 55 62 66 


Times .. 03 1 


10 


2 15 3 25 4 30 • 5 05 


Intervals . . 67 




65 70 65 80 


double intervals are — 






k. m. h. in. 

1 56 ,2 03 




11. in. n. m. b. in. 

2 08 2 12 .. 2 15 
Q2 



112 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES, 

The distance, measured from the 1,000 fathom line off Sunda Strait to the 150 
fathom depth off Dublat, gives a velocity of 851 miles an hour, which corresponds to 
a mean depth of 1,820 fathoms. 

Dtamand Harbour. 

This gauge is situated in the Eiver Hoogly, 40 miles from Dublat. 

Only one wave is marked on the diagram, which arrived at 20 hrs. 6 mins. 

It took, therefore, 2 hrs. 10 mins. to travel this distance, which agrees exactly 
with the time taken by the tide wave, the disturbance in each case occurring at 
the local high water. The time required by theory to travel this distance over the 
shallow water of the river, which averages 6 fathoms, at this time of tide, is 
2 hrs. min. 

Kidderpore. 

This place is close to Calcutta, on the Hoogly, and is 40 miles above Diamond 
Harbour* 

Here also only one wave is recorded, which, like that at Diamond Harbour, has 
travelled at the same pace as the tide wave, and arrives at high water, or 2 hrs. 
05 mins. after the wave at Diamond Harbour. The time required by theory is 
1 hr. 45 mins. for the average depth of 8 fathoms, but the channel is narrow and 
tortuous, and the depths vary from 11 fathoms to 3 fathoms, a change which would 
doubtless tend to impede the wave. The wave was 3 inches high. 

Beypore. 

This gauge is situated on the west coast of Hindustan. The diagram is very 
tree from waves of short period. 

An irregular small oscillation, but of longer periods than at Negapatam, to which 
this diagram bears a resemblance, is shown from the beginning of the diagram at 

hour of the 27th to 15 hrs. 57 mins., when a large wave of 8 inches suddenly 
makes its appearance. This is the first of a long series that can be followed for 
nineteen waves. These have a ^eaoi period of 58 minutes, or, for the double waves, 

1 hr. 56 mins, 

h, m. h. m. li. in. h. m. h, m. K. m. h. m. 

Times .. 15 57 17 00 17 40 18 40 19 48 20 35 21 35 
Intervals . . 

Times . . 22 32 23 26 25 1 30 2 20 3 05 4 20 
Intervals . . 53 60 65 50 45 75 75 



m. 


m. 


pi. 


I?- 


m. 


.»»• 


m. 


63 


40 


60 


68 


47 


.60 


57 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 113 



h. m.. h» m 

Times .. 5 35 6 35 


h. 

7 


m, h. m. h. m. 

30 8 25 9 20 






in. m. 

iDtervaJs*. 60 55 




m. m. 

55 55 






The douHe intervals are — 










^ 103 128 107 110 




125 95 150 


115 


110 mills. 



The distance, measured from the 1,000 fathom line off the Strait of Sunda, 
to the 1,000 fathom line off Beypore, is 2,090 miles; and the 15 hrs. 57 mins. 
wave gives a velocity of 326 miles an hour, corresponding to a depth of 1,600 
fathoms. The largest wave is at 5 hrs. 35 mins., or 13^ hours after the first 
one, and is 16 inches higlu The track of the wave is unfettered, but it has to turn 
Cape Comorin. 

Bombay. 

This gauge is situated on the inner side of the peninsula forming the harbour, 
which is, however, open to the south, whence the wave would come. 

The wave, after passing Beypore, would travel inside the Laccadive Group, where 
the depths are — as far as they are known — suflSicient to permit it by this route to out- 
strip the undulation which would pass through the Nine Degree Channel and then 
turn to the north ; a longer course, but in deeper water. 

On approaching Bombay the wave must pass over a good deal of shallow water. 
The diagram shows one crest only of any magnitude, at 18 hrs* 50 mins. This is at 
high water, and a very small disturbance is recorded at the succeeding low and high 
water. The distance from the 1,000 fathom line off Sunda Strait to the probable 
position of the 1,000 fathom line off Bombay is 2,483 miles ; and the velocity is 
336 miles an hour, corresponding to a depth of about 1,700 fathoms. The height of 
the wave may be taken as 6 inches. 

It is very remarkable that the disturbance should b? confined to this single wave, 
but the run of the tidal streams is very strong in Bombay Harbour. 

Karachi. 

Here the tide gauge Is in the narrow estuary forming the harbour. A very 
small oscillation appears at 5 hrs. 30 mins. on the 27th, which is continuous until the 
first great wave at 18 hrs. 40 mins. This wave is preceded by a well marked 
negative tvave, but the crest preceding is not in accordance with the subsequent 
period, and is too small to be taken as the wave corresponding to those selected in 
the other Indian Diagrams. The 18 hrs. 40 mins. is the first of a series of sixteen 
waves, and is 12 inches high. The mean period, omitting the laat wave, is 69 mins., 
and for the double waves 2 hrs. 18 mins. 



114 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 







h. nu h. in. h. 


m. h. 


m. h. 


m. 


h. 


ra. h. 


m. 


Times 




18 40 19 56 20 


50 21 


55 23 


10 





35 1 


50 


Intervals 




m. m. 

76 54 


m. 

65 


in. 

75 


m. 

85 




m. 

75 


m. 

70 


Times 




3 00 4 15 5 


15 6 


30 7 30 


8 


30 S 


40 


Intervals 




75 60 


75 


60 


60 




70 


70 


Times 




10 50 12 30 














Intervals 




100 














The double 


intervals are — 


















h. m. h. m. 

2 10 2 20 


2 40 


2 25 


h. m. 

2 15 




h. m. 

2 00 


h. m. 

2 20 



The distance, measured from the 1,000 &thom line oif Sunda Strait to tho 
probable position of the 1,000 fathom line off Karachi, piMSsing through the Nine 
Degree Channel, and to the northward outside the Laccadive Islands, is 3,032 nules, 
for which the 18 hrs. 40 mins. wave gives a velocity of 340 mil^ an hour. This 
corresponds to a mean depth of 1,710 fathopos; whereas th@ probable depth &om, 
existing soundings is 2,150 fathoms. In several parts of the route, however> the 
chart is a blank, and notably in the Nine Degree Channel. 

The disturbance lasts u^til the end of the diagram, or till %2 hours of the 28th. 

Aden. 

The tide gauge is p,t Steamer Point, th^^t is, in the bay behind the peninsula of 
Aden, protected from the advancing i^ave, which would hav^ to change its course 
ISO^ to reach the gauge. 

The wave would travel over 9 jniles of shallow Wftter in so doii^g, The diagram 
is free from waves of jshort period. 

The disturbance is inappreciable until 13 hours on the STth, whan a small wave 
<>f 2 inches appears- After two others, a decided wave of 5 inches ia recorded at 
17 hrs, 50 mm», ' 

This is the first of seventeen waves at fairly equal intervals, which can be 
followed with a mean period of 67 minutes ; or for the double waves 2 hrs. 14 mins, 

h. m. h. m. h. m. h. m. h. in. h. m. h. m. h. m. 

TinoBs .. 17 50 18 50 19 50 20 50 22 10 23 10 23 55 1 05 

ID. ID. ID-. in. n. m. in. in. 

Intervals,. 60 60 . 60 SO 60 45 70 70 

Times .. 2 15 3 25 jS 00 6 00 7 18 8 10 9 00 10 15 11 45 
Intervals.. 70 9§ €0 78 52 50 75 90 

^he double intervals are — 

Km. h. m. ^. m. h. m. h. m. 1*. m. b. m. h. n. 

2 00 2 1 45 2 20 2 45 2 18 1 42 2 45 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 115 

The distance, measured from the 1,000 fathom line off Sunda Strait, through 
the Nine Degree Channel and north of Sokotra, to the 1,000 fathom line off Aden, is 
3,642 miles. 

The 17 hrs. 50 mins. wave gives a velocity of 347 miles an hour, corresponding 
to a mean depth of 1,770 fathoma The prohable mean depth from known soundings 
is 2,100 fathoms. 



CEYLON. 



Eye Observations. 

The report of the Surveyor-General of Ceylon, reproduced on pp. 116 to 124, is 
interesting in many details. Unfortunately it does not furnish any precise data on 
the points of time and height of the wave. In one respect, however, it is very 
worthy* of consideration. 

At all the places where the disturbance was remarked, the observers agree that 
the period of the wave was comparatively short. From 5 to 20 minutes are named 
as elapsing between successive crests. Nov^ this is quite different from all the 
diagrams from gauges — which show only long waves ; and it is much to be regretted 
that no gauge by which comparison might have been made between eye observation 
and mechanical record was at work at any of these places. 

At no Indian tidal station are any short waves shown, of any height greater 
than 3 or 4 inches; and at Negapatam, which is only 100 miles further off, and 
which, except for being inside a bar, is equally favourably situated for receiving the 
waves — only one period of under an hour, viz., 43 minutes, is recorded. 

Eye observationa of this description are very liable to error, especially in point 
of height ; but when many independant observers at different places agree fairly, 
the evidence is much strengthened. 

The range at Galle is estimated at fi feet, at Colombo 7\ feet, at Valluwedditherai 
4 feet, at Trincomalee 8 feet, Batticaloa 8 feet, Arugam 4 feet, Hambantota 12 feet. 

These short waves must probably be regarded as super-seismic waves ; that is, 
waves of short period, but of greater height, imposed on the longer wave that alone 
affected the gauges. Their duration was brief compared with that of the long waves 
recorded on the diagrams. 

There does not seem to be any difficulty in assuming that these waves were in 
their origin synchronous with the longer imdulations, and their speed of translation 
would be about the same. It is, therefore, not surprising to Hnd the time of their 
arrival agreeing very well with that of the longep waves, as far as the incomplete 
information admits of comparison. 



US CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

At Batticaloa, however, the first wave of 24 inches was noted at 7 hours on the 
27th. This is 1 hr. 28 mins. Greenwich time, or one hour and a half before the 
great wave left Krakatoa. It must, therefore, have been due to one of the earlier 
waves* 

Assuming that it travelled at a speed of about 350 miles an hour, this wave 
must have left the Strait of Sunda at about 3.40 a.m. There is, however, no large 
wave recorded in the Strait at or about this time, none being noted as reaching the 
shores between 1.30 and 6. 

To what this early disturbance at Batticaloa was due is therefore a mystery. 
The largest wave is, however, stated to have occurred at about noon, which agrees 
with the Galle observations. 



2%6 Surveyor-GeneraVs Report on Tidal Waves on the Coast of Ceylon^ resulting fronk 
the Eruptions in the Strait of Sunda on the 26th and 27th August, 1883. 

Subveyoe-General's Office, Colombo, 
10th April, 1884. 

Sm, 

With reference to your notice of February 12th in 'Nature' of February 14th, 
page 355, I have the honour to report to you the result of my inquiries regarding the 
effects, as observed in Ceylon, of the eruptions at Krakatoa, in the Strait of Sunda, on 
the 26th and 27th of August last. The various stations from which I have received 
reports are marked on the accompanying map. 

The questions asked were : — 

(a.) The extreme rise and fall of tide, and the number of times the wave 

appeared to come and go ? 
(6.) Whether noises were heard or any motion of the earth felt ? 
(c.) The exact time as near as obtainable ? 
(d.) Whether any crack or fissure had been observed inland or along the 

coast ? 

Galle. — The Master Attendant reports that four unusual waves were noticed in 
the port at the hours of one, two, three, and half-past four on the afternoon of August 
the 27th, the last of which he witnessed hhnself, and recorded as follows : — " A 
very unusual receding of the sea, the small boats at their usual anchorage being left 
by it — a thing I had never seen before during my tenure of office, since 1860. 

" It was about 1^ minutes in recession, and then about the same time in a sort 
of suspensory standstill, when it commenced quietly to rise again, taking about the 



CAPTAIK WHARTON ON THE SEISMIC SEA WAVES. 



117 



same 1^ minutes to reach the level of our highest high water-marks, thus making, 
from the lowest mark of recession to it, a diflference of 8 feet 10 inches. 

*' The usual tide rise and fall here is about 2 feet, and so the great difiference 
caused by this disturbance was palpably from unusual recession/' 

Colombo. — The Master Attendant reports : — " I find it diflficult to get at the 
exact hour of the commencement of the tidal, disturbance in this harbour, but I am 
informed by the man in charge of the landing jetty that about 2.30 p.m. on the 27th 
of August there was a suddeto rise of the sea to about 15 inches above the highest 
spring tide, and that shortly afterwards, within 15 minutes, the sea fell to about 
3 feet below the lowest spring tide. I witnessed between 3.30 and 4.30 p.m. four 
rises and falls of the sea, and, as near as I can judge, there were 7 feet 6 inches 
between the highest point to which the sea rose and the lowest point to which it fell. 

Fig. 12. 




During this time there was a strong cun*ent in the harbour, which carried away the 
stern moorings of some of the steamers in port, and swung them roimd against the 
wind. The tidal disturbance went on more or less till 8 p.m. of the 27th, and I 
observed it again the next day about midday, but the rise and fall of the tide then 
did not exceed 1 foot." 

Negomho. — The information from this station is very meagre. The Mudaliyar 
of Alutkuru Korale North reported to the Assistant Government Agent : — " No 
changes in the sea or land occurred on the day in question. 

R 



118 CAPTAIN WHABTON ON THE SEISMIC SEA WAVES. 

^' I am informed that there had been an unusual ebb tide and flood tide twice 
within half-an-hour in the mouth of the lake." 

I have had no reports from Chilaw or Puttalam, but Mr. ViGOBS, the Police 
Magistrate of Kalpitiya (Calpentyn), sent me an interesting and quaint report from 
Mr. Vansanden, the Preventive Officer at Dutch Bay, which I give verbatim, as in 
one paragraph, where he describes the wash-away of a belt of land about 2 or 3 chains 
in extent, including the burial ground, it appears as if the dead had sought shelter 
with the living in a neighbouiring cocoa-nut garden I 

" The so-called tidal wave had been felt here, too, on the 27th ultimo, about 
3 o'clock p.m. The tide is said to have been observed coming in and going out three 
or four times in the space of one hour ; this had been witnessed by the fishers who had 
been out at sea. The rise of the tide was so much above the usual water-mark that 
many of the low morasses lying in close proximity to the seaside were replete with 
water that flowed into them. However, the water thus accumulated did not remain 
long, but, forming into a stream, wended its course in a southerly direction, through 
low lands, to a distance of nearly a quarter of a mile, and found a passage back to 
the sea ; thus the water that had so abruptly covered up such an extent of land did 
not take many days in draining off. 

" Eke, I must say that the receding waters were not slow behind in their action, 
for they washed away a belt of land about 2 or 3 chains in extent, including the 
burial ground situated on the coast to the south-west of the bay, designated as the 
Parava's or Fisher's Quarters, compelling the inhabitants to seek shelter in a neigh- 
bouring cocoa-nut garden. 

'* On the above date noises were heard by several persons, resembling the rumb- 
ling of distant thunder, or rather that of the booming of cannon, which lasted frt)m 
7 to 10 a.m. 

" No motion of the earth was felt, nor have I heard of any crack or fissure 
having occuired either inland or along the coast in the vicinity." 

Manndr. — The reports from this station are conflicting, and it is very doubtftd 
whether any sudden rise or fall of the sea was actually witnessed there by anyone. 
Mr. Fowler, the Assistant Government Agent, reported : — " I have caused carefril 
inquiry to be made on the subject, but find that no rise or fall of the sea was noticed 
here on the 27th ultimo, although loud sounds, resembling the report of distant cannon, 
were heard to the eastward on that date. 

" I may mention that there has been a curious change in the colour of the sun's 
disc noticed in the early morning and in the evening since the 9th instant [Septem- 
ber, 1883]. It has appeared to be of a bluish-green colour.*' 

In reporting on the state of the Searchers' House at the South Bar, the Sub- 
Collector of Mannllr wrete on September the 17th to the Collector of Customs at 
Jaifiia as follows : — ** I went to see the house on Saturday afternoon, and found it 
to be very much damaged, the sea having washed away a great part of the sand 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 119 

put for the floor of the building, although the building is at a distance of about 
255 feet from the sea. The sea appears to have risen all of a sudden, during the 
latter part of last month/' 

In forwarding a copy of this report, Mr. Twynam, the Government Agent, says : 
— ^* It appears that there must have been something unusual in the tide off the southern 
coast of Manner in August f but he adds : — " I was told by the gentlemen who came 
up in the ' Serendib ' with Mr. Justice Clarence that they were informed that nothing 
was observed at Paumben." 

It may be inferred from this that the strength of the tidal wave had become 
very much modified or exhausted by the time it reached the Gulf of Mann&r ; and 
from a further report of the Assistant Government Agent I am inclined to the belief 
that the damage done to the Searchers' House was not caused by the tidal wave. 
Mr. Twynam goes on to say : — " Nothing unusual was noticed in Jaffna or at Kaits 
in regard to the tide. No one seems to have heard any peculiar noises in Jaffna, or 
to have felt any motion of the eartL 

" I have not yet received any information of any crack or fissures having been 
observed anywhere on the coast/' 

Mr. Twynam has furnished me with reports also from the Sub-Collectors of 
Elankesanturai, Valluwedditherai and Point Pedro, on the most northerly part of 
Ceylon on the Bay of Bengal exposed to the north-west roll or wave from the Strait 
of Sunda, from which I quote as follows : — 

Kcmkesanturai. — " The extreme rise and fall of the tide, though not noted, was 
about 2 to 3 feet ; and the number of times the tide appeared to come and go, though 
not counted over at the time, would be about 3 or 4 times. No noises were heard, 
nor was any motion of the earth felt on the occasion. Though the exact time cannot 
be stated, it was first noticed about midday, when a boat with import cargo at the 
wharf was said to have got aground all of a sudden.^' 

Valluwedditherai. — " The usual rise and fall of the tide at this time of the year 
is from 2^ to 3 feet ; on the 27th ultimo the rise was, at its maximum, 2 feet more 
than ordinary ; the highest rise was at about 2.30 p.m The number of times the 
waves appeared to advance and recede was about 10 or 12. 

''A man of this place informed me that he counted 16 times from 12 to 3 p.m., 
in which the wave appeared to come and go. 

" No noises were heard, nor was any perceptible motion of the earth felt. 

^* The exact time was not noted, but it was about a quarter past 12 p.m. that the 
rise in the tide was observed. 

" No cracks or fissures have been observed either inland or along the coast." 

Point Pedro. — August the 29th, 1883. — "A strange phenomenon, such as had 

never been witnessed before by the oldest masters of vessels and others belonging to 

this place, was observed in the sea on Monday last, the 27th instant, commencing in 

the forenoon and ending about sunset. The tide rose and fell in rapid succession 

B 2 



120 OAPTAm WHARTON ON THE SEISMIC SEA WAVES. 

more than a dozen times ; and one or two boats with cargo which were floating were 
suddenly foimd to be high and dry. The wind at the time was blowing half a gale 
fi-om south-west." And Mr. Maartensz, Sub-Collector, on September the 19th, wrote 
again : — ''I have the honor in continuation of my report (August the 29th, 1883) to 
inform you that from about the forenoon till sunset of the 27th ultimo, the rise and fall 
of the sea was observed by me and the people in the wharf to have been (imlike the 
usual rise and fall of the tides) of very frequent occurrence. The rush of water, both 
when the sea rose and when it fell, was with some force, giving it a hissing sound ; 
but only once, and that was between 3 and 4 in the afternoon, the sea rose and flowed 
in beyond the ordinary limit and went down rapidly in a few minutes, so low as to 
cause a boat, which had put off with a cargo, to get aground high and dry, and another 
empty boat to capsize at the wharf. The extreme rise and fall of water was not noted 
at the time, but it must have been about 2 feet above the ordinary level at the 
tides ; and the rise and fall of the sea must have been over twenty times. The 
wind at the tijne of the occurrence was blowing rather stiff from south-west, and 
I could see, with the aid of a glass, that the vessels in the harbour were tossed 
about in different directions, and the sea about their anchorage was rising in 
bubbles. 

" No noises were heard, nor was any motion of the earth felt here or in the 
neighbourhood.'' 

MuUaittivu. — Mr. Samuel Haughton, Assistant Government Agent, in forwarding 
some interesting reports by several of his headmen, says : — " There can be no doubt 
as to the phenomena, reported by the headmen along the coast, having been connected 
with the recent fatal volcanic disturbance in the Strait of Sunda ; Mr. Parker's report 
from Hambantota as to the occurrence of the phenomena so far south, shows that 
they must have been experienced along the whole eastern coast of Ceylon. 

" The reports of the sea -coast Vidahus of MuUaittivu and Kokkulai are of special 
interest as showing that at sunrise on August the 27th the sky to the east was 
murky, and the rays of the rising sim obscured by the smoke in the Strait of Sunda. 

** The subsidence and return of the sea was noticed all along the coast.'' 

The Police Vidahu, of MuUaittivu, gives the foUowing particulars : — " The sea 
receded to 16 fathoms distance, and came back to the shore, I am told. This took 
place only once. 

" No one heard any noise here. 

" No one saw any cracks in any vUlages or in the jimgle. 

*' It did not appear that the earth shook here. 

" The sun was not bright in the morning at about 6 o'clock, and in the evening 
from 4 o'clock its rays were green." 

Similar reports were sent in by the Police Vidahus of Chemmalai and Kokkulai, 
in which it is stated that the sea receded and rose again — ^that sounds as of firing of 
cannon at Trincomalee were heard, and the Yidahu of Kokkulai states that from 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 121 

August the 27th to September the 4th the sun and moon were blue-coloured. No 
cracks or fissures were observed in the ground, and it did not shake. 

TrincoTnalee. — The Chief Clerk of the Royal Engineers Department at this 
station furnishes a report, from trustworthy information supplied by the head mason 
who was building a sea-wall at Fort Frederick, from which I quote : — 

" The extreme rise (of tide) 4 feet at an average. 
»> lall ,} 9) 

The number of times the wave appeared to come and go was about thirteen times, 
of which the sixth, seventh and eighth were those that caused more or less the 
extreme rise and fall above stated, and the rest were, of course, of a kind not to 
attract so much the notice of the working men, bearing simply the appearance of a 
little extraordinary ebb and flow of the sea-water. No noise heard (except what 
would be heard when a heavy swell of the sea would all of a sudden overflow its 
shore), nor any motion of the earth felt, 

"The exact time was 1.30 p.m. on Monday, August the 27th, 1883. 

" The sea receded three times and retiuned with force in a manner that would 
attract anyone's notice on the spot ; and the ground from the shore to a distance of 
about 30 feet, no sooner appeared bare and displayed its sediments with fishes 
struggling about, and a few men (fishers) attempted to try their luck, than the sea 
returned. In about 5 minutes the sea on that day receded and returned twice. 

" A similar change I remember took place at Gun Wharf Pier, when work was 
going on there, with a slight shock of an earthquake, on December the 31st, 1881, 
at 8 o'clock am.*' 

Batticaloa. — In forwarding reports by the Sub-Collegtor and Signaller at that 
station, Mr. Elliott, Acting Government Agent, remarks : — " I was myself absent from 
Batticaloa on that day, and observed nothing, but on the 27th ultimo, at Eoklmunai, 
Mr. Chbistie, of the Public Works Department, told me he had heard loud explosions 
seawards that morning, and that as they sounded like the discharge of heavy artillery 
he presumed some man-of-war was practising with her big guns out of sight of land^ 
as he could see no ships. 

^' Captain Walkeb and Mr. Fielder, at Tumpalancholai and Mah& Oya, on the 
Badulla road, at various times on the forenoon of the 27th, were puzzled by hearing 
noises as if blasting was going on, though there was nothing of the sort for a very 
considerable distance, if anywhere, in this district. 

** Mr. Smith, of the Public Works Department, observed the wave which came 
up the lake, and rose at his jetty about 2 feet. 

" I have not had any intimation of any fissure or crack or any motion of the 
earth in this district." 

The Sub-Collector states that about 6 p.m. on the evening of the 26th he heard 



122 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

" a loud report as if a cannon was discharged down southward," which he and the 
people near him thought to be thunder ; then, on the morning of the 27th, about 

7 a.m., he saw the water receding rapidly, and it rose quite suddenly a few minutes 
afterwards to about 2 feet over ordinary tide, which caused him to remark to the 
people that what was going on was " the effect of an earthquake somewhere," as a 
similar phenomenon occurred here on December the 31st, 1881, immediately after the 
shock of earthquake had been felt. 

" The rise and fall of water continued the whole of Monday at intervals of about 
10 minutes, the extreme rise and fall being about 2 feet each time ; at about 3 p.m. 
on Monday I heard the noise of water rushing in with some force, and on peeping 
through the window I observed the water coming foaming near the causeway, and 
this time the water rose fully 3 feet ; the rise and fall continued on Monday night too, 
and was slightly perceptible till about 10 a.m, on Tuesday. 

"At the Bar the rushing of water in and out caused several openings in the sand- 
bank, washing away a small portion of * Bones' Island ' at the mouth of the lake, as 
reported. People on boaixl the vessels at the anchorage mentioned to me that the 
vessels were much shaken about and positions changed every quarter or half hour on 
Sunday night." 

Mr. Casinadeb, the Signaller at the Flagstaff, states that ^' about midnight on 
Sunday, the 26th ultimo, I heard about five or six times a noise similar to that of a 
cannon being discharged at intervals of 15 minutes, I believe, towards the sea in the 
east. Very early in the morning I observed the cargo boats that were moored in the 
lake just opposite to Mr. Athebton's bimgalow were on the move ; but when I noticed 
it very closely, I found the rise and fall of water at intervals of about 10 minutes ; 
and, in my opinion, the height of the wave in the sea near the Bar rose to about 

8 feet about noon on Monday, and in the lake it was about 3 feet high ; and on 
Monday morning, too, about three times I noticed a noise similar to that of the 
discharge of a cannon in the sea towards the east, and after the highest rise of the 
water at noon no such noise was heard." 

The Acting Gk)vemment Agent, Eastern Province, gives further interesting 
particulars obtained by him while on a tour in the southern part of his province in 
October last, regarding the effects of the tidal wave at Arugam Bay, and of the death 
of one Moorwoman, whom he believes to have been a *' solitary victim out of Java of 
the recent earthquake." 

Arugam Bay is the most easterly bay in which ships can anchor on the east coast 
of Ceylon. It is situated nearly half-way between Batticaloa and Hambantota, and 
is directly exposed to any tidaJ wave from the direction of the Strait of Sunda. 
From the information given by the Batamahatmaya of Panama, the wave appears to 
have been felt with greater force at Arugam Bay than at any other place on the coast 
from which I have reports. 

The Batamahatmaya says : — " On one day towards the end of July " [this must 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 123 

be a mistake for August] '^ I was at Panama and heard of an accident at the Bar at 
Arugam Bay. 

" Three Moorwomen, three children, and a man were crossing it about 3 p.m. A 
big wave came up from the sea over the Bar and washed them inland. Soon after 
the water returned to the sea. The man said that the water came up to his chest : he 
is a tall man. These people were tumbling about in the water, but were rescued by 
people in boats who were fishing in the Kalapuwa (inland estuary). They lost the 
paddy they were carrying, and one of the women died two days after of her 
injuries. 

" I was further informed by the tindals [masters of vessels] in the ships anchored 
at the Bay that they felt aU of a sudden their vessels go downwards \mtil they 
plainly saw the ground, and the ships were drawn seawards, and the people on the 
shore declared the anchors were exposed to sight. After this the wave came in 
and raised the vessels and overflowed the Bar. 

" Up the Navalaru (a stream further south) where the water was heretofore 
sweet, it has been salt since that time to a distance of at least a mile and a half 
in a direct line from the sea. In Panama similarly the salt water has come a long 
way inland." 

From the testimony of the tindals and the people on the shore at Arugam Bay it 
is quite evident that the negative wave or general fall of the sea-level, was the first 
to affect the shores of Ceylon, and this is corroborated by the more accurate and 
tnistworthy information obtained by Major Baird, R.E., from the various self- 
registering tide-gauges under his charge at the Indian tidal stations, which I shall 
refer to hereafter. 

Harnhantota. — This is the most southerly siation in Ceylon from which I have 
received reports, and it completes the circuit of the island. Mr. E. M. D. Byrde, who 
was acting Government Agent at the time, reported that on the afternoon of August 
the 27th, "between the houre of 12 and 2 o'clock, the sea kept on rising several 
feet above its ordinary level, and receding to a great distance, leaving the jetty almost 
dry, the water at the extreme end of it not being more than knee-deep. 

" About every 20 minutes the sea completely covered the jetty, and rose so high 
that it washed away one of the old surf-boats that was high and dry near the main 
road. I sent out a canoe to bring back the boat, but the current was so strong that 
it was impossible to save it, as it was carried with great rapidity across the bay and 
then dashed to pieces on the opposite shore. 

" The waves did not, as is sometimes the case, break on shore with violence, but 
the sea rose gradually and similarly receded, and I should say, judging from an 
examination of the shore this morning, that it must have risen 12 feet, or more, above 
its ordinary leveL 

" The fishermen with some difficulty saved the canoe, and with the help of a 
large gang of prisoners the cargo boat was saved from being carried out to sea. 



124 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 



'' The oldest inhabitants here never previously witnessed such an occurrence, and 
they considered it worthy of notice." 

I annex a list of the barometrical observations made on the 26th and 27th 
of August last at — 









Mean reading for the 
Month. 


Difference. 




9iA.u. 


3|P.M. 
























9i A.M. 


3^ P.M. 


9i i..u. 


3i P.11. 


:g rColombo 


29-832 


29-721 


29-862 


29-768 


--020 


--037 


04 


Galle 


29-769 


29-628 


29-848 


29-728 


--074 


-•100 


^ 


Hambantota 


29-789 


29-675 


29-811 


29-712 


--022 


-•037 


Batticaloa 


29-776 


29-667 


29-800 


29-711 


-•024 


-•044 


o 


^Trinoomalee 


29-697 


29-470 


29-636 


29-637 


--039 


-•067 


•$ fColombo 


29-863 


29-749 


29-852 


29-788 


+ •011 


-•009 


§5 Galle 


29-859 


29-653 


29-843 


29-728 


+ •016 


-•075 


a ■{ Hambantota 


29-809 


29-689 


29-811 


29-712 


-•002 


-•023 


■^ Batticaloa 


29-834 


29-761 


29-800 


29-711 


+ •034 


+ •050 


O LTrincomalee 


29-611 


29-609 


29-636 


2^-637 


-•025 


-•028 



from which you will observe that there was a certain amount of disturbance visibly 
recorded on these days. 

I am, Sir, 

Your obedient Servant, 

J. STODDART, 
Acting Sunjeyor-Genercd of Ceylon, 
G. J. Symons, Esq., Chairman^ 
Krakatoa Committee, 

Royal Society, 

London. 



INDIAN OCEAN. 



Eye Observations. 

In none of the islands in the Indian Ocean are tide gauges at work. Dr. 
Meldbtjm, however, has collected several interesting accounts of the phenomena of 
rise and fall of the sea at Mauritius, Seychelles, Cargados Garajos and Rodriguez^ 
which are given in full below. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 125 

Port Louis, Mauritius^ 

" Opposite the gasworks, on the southern side of the harbour at Port Louis, Mr. 
Darney observed that the sea water was going and coming the whole forenoon of 
August 27th, but at first the movement did not attract much attention. The tide 
did not rise as usual, and it was difficult to bring the lighters close enough to the 
shore. At about 13 hrs. 30 mins. the water came with a swirl round the point of the 
sea wall, and in about a couple of minutes returned with the same speed. This 
took place several times, the water on one occasion rising 2^ feet. The water was 
^ery muddy and agitated, and quantities of jelly fish were thrown on shore. Similar 
phenomena occurred on the 28th, but to a less extent. 

" On the northern side of the Trou Fanfaron, a narrow channel on the north- 
eastern side of the harbour of Port Louis, Captain Ferrat observed at some time 
between 13 hrs. 30 mins. and 14 hrs. on the 27th, that the water, which was then 
unusually low, suddenly rushed in with great violence, rising fully 3 feet above the 
former level. An alternate ebb and flow then continued till nearly 19 hours, and the 
intervals in time between high and low water were about 15 minutes. There was no 
high wave or billow, but strong currents, the estimated velocity of which was ftboiit 
3 knots in 10 minutes, or 18 knots an hour. Vessels moored near the Dry Docks 
swayed much, and at about 18 hrs. 30 mins. one of the hawsers of the * Touareg^ 
10 inches in circumference, parted. Buoys in the neighbourhood were at times seen 
spinning round like tops. Disturbances were observed on the 28th also, and there 
were unusual currents even on the 29th. 

" Another observer, Mr. Isbesteb, on the opposite side of the Trou Fanfaron, 
noticed, at 14 hours on the 27th, that the water around the ' 5^cZZa,' moored within a 
few yards of him, had a boiling appearance. Suddenly the water receded about 
20 feet, leaving. some boats partlj'^ on dry land. About a quarter of an hour after, 
the water rushed back and advanced about 6 feet farther inland than where it was at 
14 hours. The water then receded, and a series of oscillations took place, lastmg till 
at least 18 hours. The intervals between high and low water were from 15 to 20 
minutes, and the range of rise and fall, wiiich at first was about 3 feet, gradually 
subsided after 16 hours. It was feared that the warps of the ^Stella' would give 
way. Similar phenomena were observed on the 28th, and to a small extent on 
the 29th. 

, "The Trou Fanfaron is fi:om 200 to 300 feet in width, and about 1,600 in length, 
running nearly east to west, except near its junction with the main harbour, where it 
trends to S.W. 

"As far as I can ascertaii), no disturbances were observed in the central part 
of the main harbour, which runs nearly S.E. and N.W., and where there is a greater 
depth of water. Nor does it appear that any were observed outside the harbour. 



126 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

Tomheau Bay, Mauritius. 

" At this bay, which is 3^ miles north of Port Louis, and lies east and west, 
the sea suddenly receded at about 14 hours on the 27th, and numbers of fish were 
caught on the exposed beach. Some time after, the water returned with great force. 
A series of oscillations then took place. 

Arsenal and Turtle Bays, MauHtius. 

*' Mr. CoMMiNS reports that in the bays, which are l\ miles north from Tombeau 
Bay, and which also lie east and west, similar phenomena commenced about noon on 
the 27th, and lasted till at least 17 hours on that day, the sea rising and falling alter- 
nately to the extent of 2 to 3 feet, and the maximum disturbance occurring at about 
14 hours. Between the two bays there is a bar. * Arsenal' being the outer, and 
.* Turtle ' the inner bay. A coaster of 1 5 tons burthen, while passing at 14 hours from 
Arsenal to Turtle Bay, stuck on the bar ; about 5 minutes after, the sea rushed in 
from Arsenal Bay and sent the boat flying into Turtle Bay, where, after having made 
two or three rapid revolutions, it was thrown on the north shore."' 

SoniUac, Mauritius. 

** In this harbour, which is on the south coast of Mauritius, several coasters were 
driven from their anchorage." 



*o^ 



The most remarkable thing to be noticed in these reports is the time that is 
stated to have elapsed between the crests of the long waves. 

This is said to be about 30 or 40 minutes, which is much less than the interval 
given by the nearest tide gauges at the South African ports, but more than the 
interval of the Ceylon waves. From the position of Port Louis, on the western side 
of Mauritius, or that farthest removed from Java, it is probable that the waves which 
passed by the north and south points of the island would arrive separately at the 
harbour, and that the phenomenon was doubled. The true periodic time would then 
be from 60 to 80 minutes, which would agree better with the diagrams. 

It appears possible, therefore, that the waves here recorded were the long wave^ 
felt by the gauges. The Trou Fanfaron being the narrow termination of the funnel- 
shaped harbour, the effect of the wave would be considerably increased. 

The time of the arrival of the first wave, given at about 14 hrs. 15 mins. of the 
27th, corresponds to a velocity of 403 miles an hour for the 2,842 miles that 
separate the 1,000 fathom line off Sunda Strait from the 1,000 fathom line off 
Port Louis. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 



127 



This is a higher speed than is given by other observations, but it is to 
be remarked that the wave selected from the diagrams of self-registering gauges 
for comparison, as the first of a regular series of higher waves, is. generally 
preceded by other distinct though smaller undulations, and that there is nothing 
in these eye observations at Port Louis to enable such comparatively small 
distinctions to be made ; and that the time here recorded is that of the first 
disturbance observed. 



Mah6, Seychelles. 

** Mr. EsTRTDGE, at 16 hours on the 27th, saw the sea rushing in at the rate of 
about 4 miles an hour, and rising to the extent of 2 feet range. The water returned 
and receded ; and this flow and ebb continued all night and all next day, but the 
action was quicker and the rise less. From 10 hrs. 15 mins. to 12 hrs. 5 mins. on 
the 28th, the following observations were made in a channel 23 feet wide and walled 
on both sides : — 







Rise 






Rise 


Time. 


Water ran. 


in 
inches. 


Time. 


Water ran. 


in 
inches. 


h. m. 






h. m. 






10 15 


Water ran ont 





Noon 


Water ran in. . 


10 


10 27 


„ in. • 


10 


12 10 


„ out 


— 


10 35 


„ ont 


— 


12 25 


in. . 


10 


10 40 


in. . 


10 


12 27 


ont 


— 


10 50 


„ ont 





12 45 


in.. 


10 


11 20 


„ in. . 


3 


12 50 


ont 


— 


11 25 


„ ont 





12 55 


„ in. • 


10 


11 30 


„ in. . 


10 


13 05 


ont 


— 


11 40 


oat 


— 









According to these observations, the mean interval in time between the epochs 
of high water was 21 minutes. Mr. Estridge says that the action continued 
throughout the rest of the 28th, and also during a part of the 29th, but less 
frequently. 

The height of the waves is less than those observed at Mauritius, but the 
journey over the long and shallow Seychelles bank probably killed the wave. These 
seem to be short waves similar to those observed in Ceylon. 

The time here mentioned by Mr. Esthidge would give 373 miles an hour for the 
2,873 miles, measured from the 1,000 fathom hne off Sunda Strait to the outer 
soimding on the edge of the Seychelles bank, of 200 fathoms, which is, however, 
probably nearly identical with the 1,000 fathoms, as the bank is steep. 

s 2 



128 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

Cargados Garajos. 

" On August 27th, the * Evelina/ Captain Elault, was at anchor on the west- 
north-west coast of Avocaire Island (one of the St. Brandon islands, which are 
between 16° 15' and 16° 57' S., and 58° 41' and 59° 26' E.) in 3f fathoms, a cable s 
length off shore. At 15 hours on that day it was observed that the sea suddenly 
advanced about 20 feet beyond the highest water-mark. As it was then ebb tide 
this phenomenon appeared very strange. The water soon receded with a rapid 
motion, and the shoal patches appeared quite dry to a very long distance from the 
island Before fifteen minutes had elapsed, the water rose again with the same 
velocity, coming up to the first mark. It was not a wave, nor a billow, nor a high 
sea ; the water was smooth, except where there were heads of coral, and there only a 
few wavelets were formed. This to and fro motion lasted up to 19 hours; at first 
the intervals between high and low water were about 10 minutes, and towards 
18 hours, 20 minutes. The current was setting towards E.N.E. of the compass at 
the rate of ten miles an hour. The sea was not rough outside, nor at the anchorage, 
nor eight miles N.N.W. from it, where two boats had been fishing from morning till 
14 hours. At a quarter of a mile from Avocaire, these boats were caught at 16 
hours by the receding tide, and left high and dry for 10 minutes. Similar phe- 
nomena occurred between 4 hours and 7 hours on the 28th, but they were less 
intense ; and only four alternate motions of the se^- water were observed.'' 

Here also the periods of the waves are reported as small, from 20 to 40 minutes. 
The 20 feet, mentioned as being the distance above high water-mark, to which the 
wave reached, would on the flat sandy shores of the island correspond to perhaps 
18 inches or 2 feet of vertical height. The speed calculated from the recorded time 
of 15 hours would be 370 miles an hour for the 2,662 miles, measured from the 1,000 
fathoms off Sunda to the outer sounding of 40 fathoms off Cargados. 



Port MathuHn, Rodiiguez. 

" Serjeant-Major Walus observed at 13 hrs. 30 mins. on August 27th, a peculiar 
appearance of the sea-water in the inner harbour. It was then ebb tide, and most 
of the boats were aground. The sea looked like water boiling heavily in a pot, and 
the boats which were afloat were swinging in all directions. The disturbance 
appeared quite suddenly, lasted about half an hour, and ceased as suddenly as it had 
commenced. At 14 hrs. 20 mins. a similar disturbance began ; the tide all of a sudden 
rose 5 feet 11 inches, with a current of about 10 knots an hour to the westward, 
floating all boats which had been aground, and tearing them from their moorings. 
All this happened in a few minutes. The tide then turned with equal force to the 
eastward, leaving the boats which were close in-shore dry oh the beach, and dragging 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 129 

the Government boat (a large decked pinnace) from heavy moorings, and leaving it 
dry on the reefe. The inner harbour was almost dry. The water in the channel was 
several feet below the line of reefs j and, owing to the sudden disappearance of the 
water, the reefs looked like islands rising out of the sea. The tides continued to rise 
and fall about every half hour, but not so high, or with the same force, as the first 
tide. By noon on the 29th, the tide was about its usual height, and appeared to be 
settled. The water was very muddy, and not nearly so salt as sea-wate^ usually is ; 
it was little more than brackish." 

Here the wave of 14 hrs. 20 mina is stated to be the first high one, and is 
therefore taken for comparison. 

The velocity of the wave would, therefore, be 376 miles for the distance of 
2,519 miles from the 1,000 fathom line from Sunda Strait to the outer sounding of 
200 fathoms on the eidge of the steep bank off Rodriguez Island. 

The height of 5 feet 1 1 inches appears precise, but it is so large compared with 
other records at places at this distance from Krakatoa, that some doubt is permissible 
as to its correctness. It is not stated how it was measured, and from my personal 
knowledge of the island and of its flat, fringing reefs, 1 think that an eye estimation 
would be liable to considerable error, and I do not fancy that any gauge has been 
erected since my visit in 1874. 

The remark on the brackishness of the wat6r may be taken as evidence of the 
imagination of the observer. 



SOUTH AFRICA AND THE ATLANTIC. 



Tidal Diagrams. 



Port Alfred. 

The first of the more distant tide gauges is that at Port Alfred, in South Africa, 
4,624 miles, with an uninterrupted sweep from Krakatoa. This gauge, although 
placed inside a bar, gives a very good diagram. It is on the scale of 1^ inches to 
the foot, and 1 inch to the hour. The curve is quite smooth to 7 hrs. on the 27th, 
when an irregular oscillation commences sharply. This gradually increases to a 
height of 6 inches, when a distinctly higher wave, of a height of 1 foot 4 inches, 
is shown at 17 hrs. 10 mins. 

Eleven waves of an average interval of 65 minutes can then be traced, although 
their height is much varied by interference. One cannot be sure that the 17 hrs. 



130 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

10 mins. wave is that which should he taken as corresponding to the 10 o'clock wave 
from Krakatoa^ hut it is apparently the commencement of a fresh series of waves, 
no period of former waves falling in with it, and I have therefore selected it as the 
comparison wave. The waves in this series are as follows : — 



Times . . 


h. m. h. 111. h. m. 

17 10 18 17 19 22 


h. m. 

20 30 


h. nu 

21 28 


h. 

22 


m. 

44 


Intervals . 


m. in. 

67 65 


m. 

68 


m. m. 

58 76 




m. 

64 


Times . . 


23 48 1 01 2 03 


2 55 


4 06 


5 


05 


Intervals . 


73 62 


52 


71 59 






double intervals will be : — 












n. m. h. m. h. m. 

2 12 2 06 2 20 


h. m. 

2 15 


h. m. 

2 03 







The distance, measured from the 1,000 fathom line off Sunda Strait to the 1,000 
fathom line off Port Alfred, is 4,550 miles, and the velocity for the 17 hrs. 10 mins^ 
wave will be 388 miles an hour* This corresponds to a depth of 2,245 fathoms, 
which is probably not far from the truth, though the few soimdings which exist on 
the route, are all over 2,500 fathoms. 

1'he first wave that appears at all, which is very well marked at 7 lirs. 09 mins. 
on the 27th, can be followed for twelve undulations thus : — 

h. m, h. m. h. in. h. ni. h. m. h. m. 

Times ,. 7 09 8 18 9 29 10 40 11 50 13 02 

m. m. m. m. m. m. 

Intervals . 69 71 71 . 70 72 69 

Times . , 14 11 15 20 16 35 17 45 miss 20 10 21 28 
Intervals . 69 75 70 145 78 

The mean interval is 71 minutes. 

The second wave, at 7 hi-s. 21 mins., can be followed still further for seventeen 
undulations, with a mean interval of 77 minutes, as folioM^s : — 



Times .. 


h. ni. h. m. h. m. li. 

7 21 8 38 y 57 11 


m. h. m. h. nu 

16 12 35 13 41 


Intervals . 


m. m. ni. 

77 79 79 


m. m. m. 

79 66 71 


Times . , 


14 52 16 07 miss 18 33 19 


52 21 11 miss 23 49 


Intervals . 


75 146 79 


79 158 74 


Times . . 


1 03 2 23 miss 5 04 




Intervals . 


80 161 





CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 131 

The second series of large waves, which commences with one at 18 hrs. 33 mms., 
can be followed for ten undulations, with a mean interval of 55 minutes, 843 
follows : — 



Times 


h. 
18 


m. 

33 


h. m. li. m. h, m. h. m. 

19 23 20 14 21 12 22 08 


Intervals . . 




xn. 

50 


m. m. aft. m. 

r.l 58 56 56 


Times 


23 


04 


24 00 miss 1 52 miss 3 47 


Intervals . . 




m. 

56 


m. ' m. 

112 115 



It will be seen that none of these series but that first given will coincide with 
the wave at 17 hrs. 10 mins. 

The maximum wave is at 23 hours on August 27th, with a height of 1^ feet ; 
and the disturbance continues to 10 hours of tiie 29th of August 

The complications of waves make this one of the most difficult diagrams to deal 
with. To what are these earlier waves attributable ? This diagram should afford a 
clue, as the abruptness of the first appearance of the disturbance at 7 hrs. 09 mins. 
deserves remark, and differs from other diagrams. 

But supposing the speed generally deduced from the waves to be approxi- 
mately correct, the wave that caused this first disturbance must have left Krakatoa 
at about 23 hrs. 30 mins. on the 26th, local time, at which time there is no record 
of a wave of any height in the Strait of Sunda, The wave from Krakatoa of 
1 hr. 42 mins. of the 27th was recorded faintly on the diagram at Batavia, but this 
wave was, from the absence of corresponding damage effected on the coast near the 
volcano, a small one, and it is hardly to be supposed that it could show so sharply 
on the Port Alfred gauge. Supposing, however, that the 7 hrs. 09 mins. wave is 
due to the 1 hr. 42 mins. wave, from Krakatoa, it travelled at a rate of 424 miles 
an hour. 

Port Elizabeth. 

The Port Elizabeth gauge diagram is not satisfactory, the tracing having been 
very carelessly made, so that the hour lines are very inaccurate. 

The scale is 1 inch to the foot, and 1 inch to the hour. 

The gauge is much more exposed than that at Port Alfred, and feels the local 
waves more. 

The diagram at noon, August 26th, begins with continuous oscillations of a few 
inches, which get slightly larger till 16 hours of the 27th, when two waves of 9 inches 
height follow one another at 1^ hours interval. 

At 19 hrs. 54 mins. comes an unmistakably large wave of 4 feet range, which I 
take for the comparison wave. 



1 



132 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

The disturbance is henceforth well marked with apparently but littie interference, 
but, nevertheless, the intervals of series of waves do not come out well. Six waves 
follow the comparison wave with periods of 70 minutes. Afterwards they cannot 
be satis&ctorily followed for about 6 hours, when the same period can again be 
recognised. 

Starting with the same wave at 1 9 hrs. 54 mins., twenty-two waves can be taken 
with an average period of 2 hrs. 24 mins. 

The 19 hrs. 54 mips, series is as follows :— 

h. xn. h. m. h. m. h. m. h. m. h. m. 

Times .. 19 54 21 04 22 14 miss 33 1 46 2 57 

m. m. m. . in. m. 

Intervals.. 70 70 139 .73 71 

The distance, measured from the 1,000 fathom line off the Strait of Suhda to 
the 1,000 fathom line off Port £lizabeth, is 4,611 miles, for which the 19 hrs. 
54 mins. wave gives a velocity of 3-20 miles an hour. The speed for Port Alfred, 
only a few miles eastward, is 388 miles, and therefore these discordant results cannot 
be considered satisfactory, as Port Elizabeth would give a mean depth of 1,505 
fathoms, whereas Port Alfred gives 2,245 fathoms; the track of the waves lying dose 
to one another. 

It is not possible to make them agree without straining the evidence, if the 
comparison wave be selected as being the first of a comparatively regular series ; but 
if the 17 hrs. 52 mins. wave be taken, which might' be done by a mere eye selection, 
the speed of the wave would stand at 371 miles, which would agree better with the 
adjacent gauges of Port Alfred and Table Bay. 

The series of longer periods, starting with the 19 hrs. 54 mins. wave, is as 
follows : — 



Times . 
Intervals 

Times . 
Intervals 

Times . 
Intervals 

Times . 
Intervals 



Ii. m. h. m. h. m. h. m. h. m. h. ni. 

19 54 22 12 33 3 00 5 25 7 38 



h. m. 


h. m. 


h. m. 


h. m. 


h. m. 


h. m. 


2 18 


2 21 


2 27 


2 25 


2 13 


2 22 



10 00 12 20 14 37 17 20 1942 22 lO 

2 20 2 17 2 43 2 22 2 28 2 26 

36 2 50 5 37 8 04 10 22 . 12 40 

2 14 2 47 2 27 2 18 2 18 2 23 

15 03 17 28 19 54 22 04 

2 25 2 26 2 10 



Twenty-two waves in all, with a mean period of 2 hrs. 23 mins. 

In connection with the disturbance at Port Elizabeth, the following letter fi'ofn 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 133 

the Captain of one of the large mail steamers then laying in the bay is interesting, 

as showing that horizontal movement^ and that of a rapid character, was taking 

place at the time the larger waves began to arrive : — 

" The 'Hawarden Castle ' was at anchor in Algoa Bay with starboard anchor and 

60 fathoms of chain, the anchor being in 6f fathoms. At about 8 hrs. 30 mins. p.m. 

on the 27th of August, wind S.E., moderate breeze with a little sea, ship riding head 

to wind, 1 observed the ship suddenly swing with head to N.E., bringing wind and 

sea abeam. My first impression was that our cable had parted, but on going forward 

I found a heavy strain on the cable caused by the anchor still bearing S.E. from the 

ship. So heavy was the strain that the friction brake, by which we always ride, and 

which is powerful enough to part the cable, would not hold. I at once dropped the 

second anchor, and, on paying out cable, the ship seemed to drift bodily to the N .W,, 

her head still pointing to the N.E. When we had an equal strain on both cables, I 

had time to remark to the chief oflScer the strangeness of the occurrence, and while 

speaking (about 8 hrs. 50 mins. p.m.), the ship again turned round with her head to 

wind and sea (S.E.). We remained in this position about 8 minutes, when we again 

swung with head to N.E., but on this occasion more slowly than at first. From this 

hour till midnight we occasionally headed the wind and sea, but only for a short time, 

when back we went again, head N.E., with wind and sea abeam. After midnight 

the wind got very light, and at 3 hours a.m. we were heading the S.E. swell in 

a calm. 

•* (Signed) M. P. Webster." 

This swinging of the ship means that a current was setting out from the 
shore. 

Now, the time here recorded, 8 hrs. 30 mins. p.m., is just midway between 
the times of arrival of the first and second crests in the series taken for 
comparison ; and therefore the water would be retreating from the coast and setting 
seaward. 

Table Bay. 

This diagram is a good one, but the gauge is evidently influenced by small local 
waves. The scale is one inch to the foot, and half an inch to the hour. 

The first large wave is well marked, though the oscillation before it, is somewhat 
higher than those preceding. 

The greater waves are ushered in by small undulations for some hours ; then 
comes a large wave, of 9 inches range, at 18 hrs. 42 mins. of the 27th, followed by a 
etill larger series of 18 inches. These cannot be followed for more than 12 hours, 
interferences preventing identification, though the disturbance continues to 19 hours 
of the 29 th of August. 

As the 18 hrs. 42 mins. wave falls in very well with the period of the succeeding 

T 



134 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

series, I have taken it for comparison. The series is of 13 waves with a mean period 
of 62 minutes, and a period for the double waves of 2 hrs. 05 mins. 





h, m. h. m. h. m. h. m. h. m. h, m. h. m. 


Times 


18 42 19 50 20 53 22 05 23 07 23 58 52 




ui. m. m. m. m. m» m. 


Intervals . . 


68 63 72 62 51 54 68 


Times 


2 00 2 50 3 58 5 00 6 18 7 12 


Intervals . . 


50 68 62 78 54 



There is no interference so far, nor any second series. In this respect the 
diagram greatly differs from those of Port Elizabeth and Port Alfred. 

The gauge is situated inside the breakwater, and the wave would, in coming into 
it, have passed round a complete circle from its original course from Krakatoa. 

The tracks followed by the waves to these three South African ports are not 
identical, though they do not lie far apart, and are sufficiently near to enable us to 
assume that the mean depth passed over by the separate waves is not far from the 
same. The Port Alfred wave would give a depth of 2,245 fathoms ; that to Port 
Elizabeth 1,505 fathoms; and the Table Bay wave 2,010 fathoms. These are all for 
the deep water portion of the tracks, starting from the assumed position of the 
1,000 fathom line off the Strait of Sunda, to the same depth off the South African 
ports. As imfortunately the sounding of the Indian Ocean is very incomplete, it 
cannot be certainly stated from actual observation what the true mean depth is ; but 
as all the soundings yet obtained on the line of the wave are over 2,500 fathoms, 
it may be assumed to be in all probability not less than 2,300 fathoms. On this 
assumption the Port Alfred record agrees fairly with the time calculated from the 
formula, but the Port Elizabeth and Table Bay waves are too late. 

Fort Molthi. 

At Port Moltke, in the inland of South Georgia, a tide gauge was working under 
the supervision of the German South Polar Expedition. 

The scale is 2'^'1 inches to a foot, and 0'8 inch to an hour. 

This position is well open to the sea. The diagram is good, but presents great 
difficulties. 

After small oscillations of 3 inches, a larger wave of 11 inches suddenly appears 
at 14 hrs. 29 mins. of the 27th. This is followed by three other waves with a mean 
period of 63 minutes ; after which the regularity is lost. 

h. m. h. m. h. m. h. m. 

Times . . . . 14 29 15 42 16 45 17 40 

m. m. m. 

Intervals •. ,. 73 63 55 



CAPTAIN WHAHTON ON THE SEISMIC SEA WAVES. 135 

If the first of the series be taken for th^ comparison wave, it gives an average 
speed of 487 miles an hour from Krakatoa, which I cannot but think is extremely 
improbable, corresponding as it does with a depth of 3,500 fathoms. 

These undulations diminish after 21 hours, but at 1 hr. 45 mins. on the 28th 
another wave of 1 5 inches is recorded, which is followed by others for 20 hours. 
These waves are complicated and apparently belong to two series of about the same 
period. The first series of 62 minutes period is — 

b. m. h. ID. h. m. h. in. h. m. h. m. h. m. h. m. 

Times . . 1 44 2 46 3 47 4 45 5 48 6 51 8 07 9 07 

m. m. m. m. m. in. m. 

Intervals.. 62 61 58 63 63 76 60 

Times .. 10 00 11 08 12 03 12 56 13 55 14 53 16 08 

Intervals 53 68 55 . 53 " 59 58 75 

The double interval is 2 hrs. 3 mins. 

The second series of a mean period of 63 minutes is — 





h. m. h. m. h. m. h. m. h« m. h. in. h. m. 


Times . . 


.. 2 20 3 25 4 21 5 21 6 18 7 22 8 28 




m. m. m. m. m. m. m. 


Intervals . . 


65 56 60 57 64 66 65 


Times 


.. 9 33 10 41 11 40 12 39 13 44 14 47 15 55 


Intervals , . 


68 59 59 65 63 68 65 


Tunes .. 


. . 17 00 17 55 19 12 20 15 


Intervals . . 

mi _ J 11 


55 77 63 

_ • 1 1 • ^ 1 ^ • 



The double interval is 2 hrs. 6 mins. 

If we take the wave at 1 hr. 44 mins. for comparison, the speed — calculated for 
the distance from the 1,000 fathom line off Sunda Strait to the 100 fathom line off 
Port Moltke, which is 6,619 miles — is 266 miles an hour. This is apparently as low 
as the other speed calculated firom the first large wave at 14 hrs. 29 mins. of the 
27th is high ; but the track foUowed by the wave from Sunda Strait passes in one 
place south of the Kerguelen Group, where soundings of 160 fathoms have be6n 
obtained, and afterwards passes through the pack of Antarctic ice for many miles ; so 
that retardation may not unreasonably be assxuned, as the depths are probably not 
great on this course. 

To what cause the earlier waves are to be attributed I am unable to suggest, as 
the duration of a regular series is not long. The period is not unKke that recognised 

t2 



136 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

in so many of the diagrams discussed, and visible in the later series of waves on 
this gauge. 

Altogether the results from this station are not satisfactory. Dr. Neumayer, 
the Director of the Deutsche Seewarte, Hamburg, has assured me that there is no 
error in the times used. 

Orange Bay, Cape Horn. 

The French Meteorological Expedition had an automatic tide gauge at work at 
Orange Bay. The photographic copies fiu-nished are very small, but I have had 
them enlarged by photography for purposes of measurement. 

This is an interesting diagram, and seems to indicate that two distinct series of 
waves arrived, one five hours before the other. 

The south pole, with its unknown lands, but more or less known icy barriers, 
intervenes between the Strait of Sunda and Cape Horn. Thus a wave would have 
to travel round these obstructions, and would pass on both sides, the distance by the 
west being about 7,520 miles, and by the east about 7,820. 

I have come to the conclusion that the earliest waves were those that travelled 
the greatest distance, for the following reasons : — 

A careful examination shows that the eastern wave is unfettered by islands, and 
that the sea from the few known depths is probably deep. By the other route, on 
the contrary, the Kerguelen Group is passed, and hereabouts the depths do not 
exceed 200 fathoms ; also on passing between the Sandwich Land and South Georgia 
a more or less shallow sea is in all probability travelled over. 

The course of the western wave is, for the greater part of the distance, identical 
with that which reached South Georgia, in which case we have seen that its speed was 
probably low. If the early waxes are taken to be those .which passed south of South 
Georgia, it will appear that they arrived at Orange Bay 1^ hours earlier than at 
South Georgia, which, seeing that the distance is 850 miles greater, seems 
impossible. 

The gauge was situated in a bay inside a good many islands, which would tend 
to impede the wave and cause irregularities. 

The diagram shows small and irregiJar disturbance from the commencement, but 
at 21 hrs. 57 mins. on the 27th there is the first of a short series of four waves with 
a period of 37 minutes as follows : — 

h. m. h. m. h. m. h. m. 

Times . . . . 21 57 22 37 23 13 23 47 

m. m. in. 

Intervals .. 40 36 34 

Another wave follows, but at 54 minutes interval. The disturbance then dies down. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 137 

but at 4 hrs. 57 mins. on the 28 th there is the first of a second series of eleven 
waves, with a mean period of 36 minutes, as follows : — 

h. m. h. m. h. m. h. m. h. m. h. m. 

Times .. , . 4 57 5 32 5 58 6 33 7 06 7 46 

m. m. m. m. in. m. 

Intervals .. 35 26 35 33 40 30 

Times .. . . 8 16 8 57 9 37 10 15 11 00 

Intervals . . 41 40 38 45 

The maximum height of the waves is 7 inches, occurring at the third wave of 
the first series. The speed of the first series, taken, as I have said, by the eastern 
route, is 347 miles an hour; of the second, by the western route, 251 miles ; which 
agrees very fairly with that of the South Georgia wave, and tends to show that 
this conclusion is correct. The diagram shows disturbance till the end, viz., until 
noon on the 29th, but this is irregular and probably due to local causes. 

If these waves are due to Krakatoa, they seem to be again broken up, as the 
mean period is roughly half of that noted on former diagrams. 

For the second and longer series, the double intervals are : — 

61 68 70 81 83, or a mean of 73 minutes. 



Colon, Isthmtis of Panama. 

The Colon diagram presents features utterly unlike any other of the gauges 
under discussion, at a distance from the Strait of Sunda. 

Commencing very sharply and distinctly, a negative wave of 5 inches is followed 
by a positive wave of 13 inches range, the first of a series of sixteen waves with a 
period of 70 minutes, remarkably regular, with no sign of interference, and gradually 
dying away in a manner difierent from all others recorded. 

The time of arrival of the first wave is 16 hrs. 30 mins., which gives a speed of 
026 miles an hour. 

As this corresponds to a mean depth from the Strait of Sunda of over 5,000 
fathoms, and, over the greater part of the distance, the depth is known, and is about 
2,400 fiithoms, — this result may be regarded as out of the question ; and the 
waves which disturbed the Colon gauge must be ascribed to some other cause than 
Krakatoa. 

As the whole of the coast on which Colon lies is subject to rollers of various 
dimensions, which set in from the Caribbean Sea, with no corresponding local change 
of wind, it appears that the origin of these waves may be sought in some such 



138 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

direction, with much less improbability than by imagining that an undulation starting 
from Krakatoa could have travelled to Colon in 18 hours, more especially as the 
arrival of the wave at Table Bay in 13^ hours necessitates its having travelled the 
remaining distance, 6,380 miles, in under 5 hours, or at a velocity of over 1,000 miles 
an hour. 



EUROPE. 

Socoa. 

This harbour, situated in the Bay of Biscay near the boundary of France and 
Spain, is the nearest place to the northward of the Cape of Good Hope at which an 
automatic tide gauge was at work. The small photographi3 reductions of the tidal 
diagrams have been enlarged three times by photography, and from them the 
measurements are taken ; the same course has been pursued in dealing with the 
diagrams for Rochefort, Cherbourg, and Havre. 

A disturbance, which though small is quite distinct, and fairly regular, appears 
at 4 hrs. 50 mins. on the 28th, and lasts 10 hours. Seven undulations can be 
followed with a mean period of 39 minutes. 

h. m. h. m. h. m. h. m. h. • m. h. m. h. m. 

Times . . . . 4 50 5 25 6 13 6 45 7 27 8 04 8 42 

in. m. m. m. m. m. 

Intervals . . 35 48 32 42 37 38 

The range does not exceed 3 inches. Taking the first wave at 4 hrs. 50 mins., 
the speed for a distance of 10,729 miles is 425 miles an hour. 

Rochrfurt. 

This gauge is situated 10 miles up the Charente River, but the converging 
character of the shores of the Basque Roads would tend to magnify the waves. 

Four can be traced with a mean interval of 55 minutes as follows, on the 28th 
of August : — 

b« m. h. in* h. m. h. m. 

Times ,.940 1035 1128 1225 

in. m. m. 

Intervals .... 55 53 57 

The range of the third wave is 5 inches. The distance is 1 0,724 miles, which 
gives a speed of 414 miles an hour. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 139 

Cherbourg. 

The disturbance on this diagram is short. The first wave appears at 9 hrs. 
20 mins. on the 28th and is followed bj four others, of an average range of 2 
inches : — 

h. m. h. m. h. in. h. m. h. m. 

Times .. . . 9 20 9 59 10 32 11 07 11 44 

m. m. in. m. 

Intervals .. 39 33 35 37 

The mean period is 36 minutes. The distance from the 1,000 fathom line 

off the Strait of Sunda to the 1,000 fathom line at the mouth of the English 

Channel, is 10,780 miles. The 9 hi-s. 20 mins. wave gives a speed of 421 miles 
an hour. 

Havre. 

This gauge, the farthest up the Channel, and at the greatest distance from 
Krakatoa of any dealt with, shows very slight disturbance ; but the undulations are 
fairly regular, though the range does not exceed 1 inch. Period 33 minutes. 

Five of these small waves can be traced as follows : — 

h. m. h. m. h. m. h. m. h. m. 

Times.. .. 1133 12 05 12 40 13 20 13 46 

Intervals .. 32 35 40 26 

Taking the distance as 10,780 miles, the speed comes out 422 miles an hour. 

Devonport. 

The original diagram is on the scale of 0'4 of an inch to the foot, and half an 
inch to the hour. TTie gauge is situated a long way up the harbour, but the form of 
the land tends to enlarge the wave. 

A slight oscillation with no regular period begins at 6 hrs. 20 mins. on the 28th, 
but at 10 hrs. 43 mins. there is a stronger wave of 6 inches range, followed by four 
others, with a mean period of 65 minutes. The intervals are not, however, very 
regular : — 

h. m. h. m. h. m. h. m. h. m. 

Times.. .. 10 43 11 35 12 46 2 10 3 05 

m. m. in. m. 

Intervals .. 52 71 84 55 

I take the 10 hrs. 43 mins. wave as the one for comparison ; and the distance 



140 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

being 11,040 miles, 10,790 of which are in deep water, the speed of the wave comes 
out at 380 miles an hour, 

Portland. 

The gauge is on the inner side of Portland Breakwater ; to reach which the 
wave has, from the entrance of the Channel, to pass for 250 miles over depths of less 
than 100 fathoms. 

The diagram here is on the scale of 1;^ inches to the foot and 1 inch to the hour. 
The indications of disturbance are not very conclusive, as no regularity of period is 
traceable in the small indentations which appear on the 28th of August. They are so 
small as not to show on the reduced diagram, but they can be seen on the original 
from 10 hrs. 15 mins. on the 28th for some hours. Taking the earliest appearance at 
10 hrs. 15 mins., a speed of 406 miles an hour comes out. 

Portiamouth and Dover. 

The gauges here show no sign of any disturbance. Seeing that the distance up 
the English Channel in shallow water is much greater than those already dealt with, 
and that the disturbances at Havre and Portland are so very shght, this is not 
surprising. 

It cannot be considered that the evidence afforded by any of these six gauges in 
France and England is conclusive ; the disturbance in all of them is too slight. But, 
looking at them collectively, and seeing the fair accordance of the speed of the waves 
— which would travel on the same course — the evidence is strongly in favour of the 
distm'bances on these gauges being the effect of one and the same cause, and one 
which originated at a great distance, or the disturbance would have been of longer 
continuance. 

Against the presumption of their connection with Krakatoa is the high speed at 
>\hich the wave must have travelled. 

In no other case does the depth corresponding to the speed come out otherwise 
than under the probable truth ; but the average velocity of 408 miles given by these six 
gauges would demj^nd a m^an depth of 2,500 fathoms, whereas it is very improbable, 
from the known soundings, that this quantity is over 2,400 fathoms. On the other 
hand, the ocean is deep over the whole course, and no checking of the velocity would 
probably occur from great irregularities of the bottom. Though the wave had to 
round the Cape of Good Hope, it would do so at a greater distance than the wave 
which reached Table Bay, and the difference between the speeds — viz., 370 miles to 
Table Bay and 408 as the average to the edge of the shallow water at the entrance 
of the English Channel — may be accounted for in this way, and also by the difficulty 
in tracing the most probable track for the wave in i caching Table Bay. 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 141 

Noth withstanding, there is a great discrepancy between the speed from Table 
Bay to the Channel, and that which the known depth should give by the formula, 
V = ^gh. This is the only case in these discussions which atFords an opportunity of 
examining the speed of the wave in different parts of its course. In no other in-^ 
stance do the tracks to different places coincide near enough to allow of a com- 
parison. 

Here we have a time of 12^ hoiu*s from off the Cape of Good Hope to the 
Channel, or a speed of 462 miles an hour. This corresponds to a depth of over 3,000 
fathoms, whereas the mean depth cannot be over 2,400 at the most, as estimated 
from the soundings, which are sufficiently numerous to enable this to be stated with 
confidence. 

The tidal wave is 14 hours later in the Channel than at the Cape, which corre- 
sponds to a velocity of 412 miles an hour, supposing it to travel from one to the 
other. Even this gives, by the formula (supposing the wave to be "free"), 2,500 
fathoms as a mean depth, which is, as before stated, more than the depth known 
to exist. It appears, therefore, either that the tidal wave which fiills the Channel 
does not originate in the South Indian Ocean, or that the formula does not give 
the speed with sufficient exactness. 



AUSTRALIA. 



Tidal Diagrams and Eye Observations. 

To the eastward of the Strait of Sunda the results are very meagre. The few 
tide gauges in Australia are badly placed, up estuaries, and, with one exception, show 
very slight and irregular disturbances. 

In New Zealand two automatic gauges are at work, but the one at Port Lyttel- 
ton, which alone shows much disturbance, is difficult to interpret ; and, moreover, the 
waves it has registered, as well as the reports of .eye-witnesses, tend to show that the 
waves felt in New Zealand had some other point or points of origin than the Strait of 
Sunda. The disturbances marked on the three gauges at the Sandwich Islands, 
Alaska, and San Francisco are, as will be seen, also apparently unconnected with 
Krakatoa. 

West Australia. 

Here there are no tide gauges ; and, as the reports are veiy crude and vague, 
not much reliance can be placed upon them. 

U 



142 CAPTAIN WHAETON ON THE SEISMIC SEA WAVES. 

Cossack^ W. Australia. 

At 4.30 p.m. on the 27th an extraordinary tide is said to have set in, which rose 
nearly 5 feet, then went out just 98 rapidly, the coming in and going out not occupy- 
ing more than SO minutes. 

This time gives a speed of 423 miles an hour for the 995 miles from the Strait of 
Sunda to the 190 fathoms off Cossack. This gives a depth of 2,600 fathoms — 
probably near the truth, 

Geraldton, W, Australia. 

Here the water is stated to have suddenly risen 6 feet at 8 p.mu on the 27th, 
and receded sa far that boats anchored in 6 feet water were left high and dry. It 
rose again, but not so high as at first, and continued rising and fidling, gradually 
getting less and less till about noon the next day, when it ceased. 

If this time be taken, it would give a speed of only 170 miles an hour from 
the Strait of Sunda. As at this time it had been dark for two hours, it may be 
regarded as doubtful whether the wave remarked at 8 o'clock was really the first that 
reached Geraldton. 

From the rapid rise mentioned^ it appears that these waves were short ones at 
both Cossack and GeraldtoOi 

Porl Adelaide, S. Australia. 

The diagram here shows disturbance, but of so irregular a character that 
nothing can be founded upon it. 

The gauge is placed inside a bar, and some miles up the river. 

WUliamistoumf Victoria. 

This bay is situated near the head of Port Phillip. The wave coming from sea- 
ward would have to pass ovet 30 iniles of shallow water after getting through the 
narrows at the entrance, where the tides are very strong. Nevertheless, there is a 
marked disturbance, which commences at 4 hrs. 30 mins. on the 28th, the range being 
only 4 inches. This lasts until the 31st, but can be followed as a regular series for 
only twenty-seven waves. The mean period is 86 minutes, but it varies considerably. 
There is only one series of waves. 

A. in* A. m. A. m» a. m. a. al a. ia. 

Times , . 4 40 6 40 8 08 9 35 10 55 12 10 

H. m. h. Ai. h. m. h.. m. a. 'm. a. m. 

Intervals 2 00 1 28 1 27 1 20 1 15 1 30 



CAPTAIN WHAETON ON THE SEISMIC SEA WAVES. 143 

ii« ID* h* nL Om nia D. in. n. hl. a. in. 

Times .. 13 40 15 10 16 35 17 50 19 05 20 10 

h. m. h. m. h. m. h, m. h. m. h: m. 

Intervals 1 30 1 25 1 15 1 15 1 05 1 30 

Times .. 21 40 23 25 1 05 2 08 3 35 5 00 

Intervals 1 45 1 40 1 03 1 27 1 25 1 45 

Times .. 6 45 7 45 9 25 11 00 12 00 13 42 

Intervals 1 00 1 40 1 35 1 00 1 42 1 23 

Times .. 15 05 16 20 17 27 19 25 
Intervals I 15 1 07 1 58 

The distance, measured from the 1000-fi^thom line from off the Strait of Sunda 
to the 130 fathoms off the entrance to Bass Strait is 3,130 miles. The 4 hrs. 40 
mina wave gives a speed of 232 miles an hour, which corresponds to a depth of 800 
fathom& The very few soundings which exist on or near this route are all more 
than 2,000 fathoms, from which it appears that if the distiurhance is connected with 
Krakatoa the earlier waves must have been so small that they were not recorded on 
the gauge. The length of the waves precludes the supposition of any local cause 
or undulations caused by gales. The original diagram is on a scale of 1 inch to 
the hour. 

Sydney, New South Wales. 

The record at this port is disturbed, but merely at high water, and no deduction 
from it appears possible. 

On the subject of the Sydney gauge, Mr. H. C. Bubbell, F.II.S., the Government 
Astronomer of New South Wales, writes as follows : — 

" I should teU you that there is always a little unsteadiness in the Sydney tidal 
'wave at high water, and when the so-called earthquake waves do reach oxu: coast, as 
they fr^uently do, they are always greatest about the time of high water. 

" Two reasons for the irregular high-water curve have been offered — 1st, that, 
when the tide wave rushes into the complex ^stem of bays forming Sydney Harbour, 
extending 20 miles in one direction and nearly as much in two others, the water 
oscillates till it comes to its level ; and 2ndly, and more probably, that the tide wave 
is divided by New Zealand, and that the two branches arrive on this coast at different 
times. 

"I mention this so that you may make allowance for it in estimating the 
disturbances recorded at high water, 

*' Again, the common so-called earthquake waves are fairly regular in interval, 
from crest to crest, being 25 minutes to 30 minutes, while the best marked of those I 
send you have a much longer intervali about 45 minutes. 

u 2 



144 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

" As soon as we heard of the great eruption at Krakatoa I tried to connect our 
recorded waves with it, but I found that the velocity for one set was too great, and 
for the other, too small. 

" I did not hear any explosions on August 27th, nor did I hear of anyone who 
heard such noises at that time/' 



NEW ZEALAND. 



Tidal Diagrams and Eye Observations. 

From New Zealand has been received a report from Dr. Hector, F.R.S., accom- 
panied by two tidal diagrams from Port Lyttelton and Dunedin respectively. The 
report gives the eye observations at different places. From this it appears that at 
10 spots on the coast, disturbance was noticed on various dates between the 28th of 
August and the 1st of September. 

I opine that none of these could have originated from the Strait of Sunda, the 
interval elapsing between the great wave there and the earliest disturbance in New 
Zealand being far too great to permit the supposition that that wave could have 
caused them. It was at Port Lyttelton, by Dr. Hector's report, that the dis 
turbance was finst noticed. 

Port LytteltoUy New Zealand. 

The tidal diagram here is on a large scale, 2 inches to the foot and 1 inch to 
the hour. 

The curve is most irregular, and unfortunately at the time Dr. Hector mentions 
as that at which the disturbance commenced, the chain was entangled. 

It is difficult to arrive at any conclusion as to the exact nature of the disturbance, 
from the absence of diagrams of any days when the movement was normal. On all 
other days for which diagrams are given, from the 28th of August to the 3rd of 
September, abnormal motion appeai-s to be taking place. 

This is of two kinds ; small oscillations with an average of about ten minutes, 
but with much variation, and larger and very irregular rises and falls. 

This is quite unlike the diagrams from other parts to the west of Sunda Strait, 
where the disturbance may be considered as undoubtedly due to Krakatoa. No 
regulax period can be recognised, and no result is obtainable. 

Taking Dr. Hector's statement that the tide ebbed and flowed in an exceptional 
manner on the evenmg of the 28th, in conjunction with the broken record of the 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 145 

gauge at that time, 9. 45 p.m. may be considered as about the hour when the first 
wave crest reached the port. 

This gives, for the distance from Krakatoa, which, eliminating the shallow water 
as before, is 4,772 miles from the 1,000 fathoms off Sunda Strait to the 100 fathoms 
off Port Lyttelton, 159 miles an hour; which corresponds to a depth of 377 fathoms. 
The true depth is probably not less than 2,300 fathoms. 



Dunediuy New Zealand. 

This gauge is situated at the head of the long Bay of Otago. It shows a disturb- 
ance merely at high water on the 29th at 3 p.m. 

Dr. Hector states that at Port Chalmers, four miles lower down the harbour, 
the water rose and fell irregularly from 11.30 a.m. to 3 p.m. on the 29th. . 

Taking 11.30 as the earliest time, the wave would have taken 45 hrs. 9 mins. to 
travel from Krakatoa, which gives a speed of 102 miles an hour for the 4,536 miles 
from Sunda Strait to the 500 fathoms off Otago. This corresponds to a depth of 
150 fathoms, the true depth being probably not less than 2,300 fathoms. 

At other places in New Zealand the discrepancy is the same, or even greater. 

Thus Dr. Hector states, that at Timaru, "a wave was experienced several 
times, and a very marked disturbance of the water occurred on the morning of 
the 29th." 

" At Nelson, at 8 p.m. on September the Ist, the tide suddenly rose to some 
distance above high water-mark, the time for high water not being tiU after 9 p.m. 
It fell again about 10 inches, after which it commenced to flow as usual." 

" At Thames, at 8.15 a.m. on the 30th of August, the tide, which had previously 
been ebbing, suddenly turned to flood, running past the lighthouse at Passage like a 
mill race for about half an hour. It then just as suddeiJy turned to ebb again, about 
two hoiu^ being wanted to low water. The disturbance was still noticed at the 
Thames on August the 31st." 

" At Auckland a tidal wave was experienced just before the last of the ebb tide 
on August the 29th. The rise was about 6 feet." 

" At Russell, Bay of Islands, and at Mongonui, tidal disturbances were noticed 
several times in rapid succession on August the 29th." 

" On August the 29th earthijuake shocks were felt at Brisbane, Bockhampton, 
and Gladstone in Queensland ; also at Patea in Taranaki District, New Zealand-" 

" At midnight, August 29th — 30th, a severe shock was felt at Kiana, New South 
Wales, about 90 miles south of Sydney." 

" On August the 31st a slight shock was felt in South Australia." 

Dr. Hector adds, after expressing his opinion that the tidal disturbances were 
probably due to Krakatoa, and referring to the great earthquake at Arica in 1868 : — 



146 CAPTAIN WHARTON ON THE SEISMIC SEA WAVBa 

^' On both occasions we had slight earthquake shocks, produced probably as a 
secondary result from the inequality of pressure, but similar slight shocks are not 
infrequent, without being accompanied by tidal disturbances." 

It will, I think, be evident that no wave that occurred more than 15 hours 
(equivalent to a mean depth of 1,300 fathoms) after the eruption at Erakatoa could 
be, under any hypothesis, attributed to it ; whereas the earliest of the disturbances 
here recorded took place 48 hours, and the latest 116 hours, after the 10 o'clock wave 
left Exakatoa. 

The diversity o£ times recorded in different places in New Zealand, as well as the 
brief duration of aome of the disturbances, seem to point to some local cause ; and it 
appears that the earthquakes mentioned by Dr. HsorOB are far more likely to have 
caused them than is the disturbance in the Strait of Sunda on August the 27th. 
I think that that gentleman will probably agree in this conclusion when he sees 
the evidence. 



THE PACIFia 



Tidal Diagrams and Eye OnsEBVATioiNs. 

We have diagranus from three places in the Pacific, viz., Honolulu ; St. Pauls, 
Eodiak ; and Saucelito, near San Francisco. 

These all show disturbance, but I do not think that it can be considered to have 
any distinct connection with the eruption in Sunda Strait^ as the speed of the waves 
deduced is in all cases too high for probability ; nor do the differences of times of 
arrival at the three stations agree with requirements of distance by the several 
tracks^ 

At the first glance at a chart it seems that the undulations to these stations 
might have ti^velled throi^h the cl\annels of the Eastern Archipdago, and thus have 
gained the Psunfic ; but a dose investigation will show that this is impossible. The 
most direct route is vid the Java and Mores Sea and the lltolucca passag6i, and north 
of New Guinea* We have already seen, however, that the wavQ travelling to Ujong 
Pan^ia— which is om this route — required 10^ hours to traverse the distance, which 
is 440 miles. BeyondUjong Pangka is another 200 miles of water of about 40 fikthoms 
before the deeper watw of the Flores Sea is reached. This would take another 
4 hours, making 14^ hours before the wave was in deep water, and it would still have 
5,400 nules to travel before reaching Honolulu. As the first large wave is recorded 
on the Honolulu diagram only 11 hours after the great wave left Eiakatoa, it is 
obvious that it had not time to proceed by this route. 

By the south of Java and vid Torres Straits, we meet with the same di£Giculty, 



CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 147 

as, in parsing the latter, a distance of over 700 miles of water averaging 30 fathoms 
in depth, must be traversed. 

The waves must therefore have passed south of Tasmania. 

Honolulu. 

This diagram, on a scale of 1*7 inches to the foot and 0*9 inch to the hour, 
shows a slight disturbance commencing at 17 hours of the 26th. At 3 hrs. 20 mins. 
of the 27th a larger disturbance commenced, and lasted, with gradually diminishing 
height, until September the 1st — a period of five days. This, then, is unlike any 
of the other diagrams. The maximum wave is about 5 inches. The waves are 
comparatively short — ^averaging about 30 minutes. Taking the 3 hrs. 20 mins. 
wave, we find, for the distance of 8,326 miles, a speed of nearly 800 miles an 
hour, which requires a depth of 9,500 fathoms, the actual depth being probably 
not above 2,300 fathoms. 

St PauFsy Kodiak, Alaska. 

This diagram, on a scale of 0*9 inch to the foot and 0*75 inch to the hour, 
shows disturbance from 8 hours of the 27th of August. A larger wave is recorded 
at 16 hrs. 45 min&, and the disturbance is marked to the end of the 30th. The 
waves are short and irregular, and the greatest wave is 3 inches. Taking the 
16 hrs. 45 mins. wave, the speed for the distance of 10,190 miles comes out 459 miles 
an hour, which corresponds to a mean depth of 3,100 fiithoma This is too much, but 
not so startling as the Honolulu result, with which it fails to agree in any way. 

Saticelito, San Francisco* 

This diagram, on a scale of 1 inch to the foot and 0*45 inch to the hour, shows 
disturbance from 7 hours on the 27th. The first large wave is at 13 hrs. 20 mins., 
and is followed for 7 hours by others, when they diminish to a small and irregular 
oscillation, which lasts until the 30th of August. The 13 hrs. 20 mins. wave is 
6 inches in height. Taking this wave, we find for the distance of 10,343 miles a speed 
of 594 miles an hour, which requires a depth of 5,000 fathoms. 

It wiU be observed that none of these speeds agree, either with one another 
or with the known facts and probabilities of the depths. 

Nor is it possible to localise any one centre from which these disturbances could 
have simultaneously originated, so that the times of arrival at the three gauges will 
agree. 

An earthquake occurring near the Sandwich Islands or to the south-west of 
them would give rise to waves which would reach Honolulu and San Francisco at 
times agreeing with the recorded differences of arrival at these places ; but it would 
be at St. Paul's six hours earlier than the registered time. 



148 CAPTAIN WHARTON ON THE SEISMIC SEA WAVES. 

Any other assumed position would make the discrepancy greater. Either the 
waves chosen for comparison on the three diagrams are not identical, nor nearly so, 
or the disturbances are not due to the same cause. 



MAIN CONCLUSIONS. 



LUGt 



kfin 



1-59 



The main conclusions at which I arrive may be summed up as follows : — 

1. That the sea disturbance was probably composed of two descriptions of waves, 

long waves with periods of over an hour, and shorter but higher waves with 
irregular and much briefer intervals. 

2. That the greatest disturbance, probably foimed of both descriptions of 

waves, originated at Krakatoa at about 10 a.m., local time, on the 
27th of August, and was, on the shores of the Strait of Sunda, about 
50 feet high. rot 

3. That the long waves of this disturbance, of an original period of about two 

hours, were alone marked by the automatic gauges. 

4. That the speed of the two descriptions of waves was about the same. 

5. That the speed of those waves that can be fairly identified, measured by the 

time of arrival of the first large wave, and counting from the 10 a.m. wave 
at Krakatoa, was in all cases less than the depth of water would demand 
according to theory ; assuming that the waves taken for comparison were 
identical with the 10 o'clock wave from Krakatoa. 

6. That the first large wave recorded on the gauges was in most cases preceded 

by smaller undulations, which did not, however, accord with the period of 
the Larger waves. 

7. That to the north and east in the Java Sea the long wave can be 

traced for 450 miles, but it was at this distance reduced to a very small 
undulation. 

8. That to the west the longwave travelled over great distances; reaching Cape 

Horn and possibly the English Channel. 

9. That the shorter waves reached Ceylon and perhaps Mauritius, 

10. That to the south and east of Sunda Strait the propagation of the dis- 
turbance was limited ; probably not extending beyond the west coast of 
Australia. 

11. That the disturbances, noted both by eye observers and by the gauges in 

New Zealand and in the Pacific, had no connection with Krakatoa, but were 
the results of other seismic action, and were apparently due to more than 
one centre of movement. 



lUGUST 26th— 30th, 1883. 



'^J 





























Fink Onat WaTe. 








lesin 
ihoal 


Tine of Ware 
in known tboBl 
depth! by Airy. 


Outer 
depth. 


Dirtuoei 

in 
MidOoeui. 






Time of 
Max. Dii- 
tarbance 
after Pint 
Great 


H^^ht 

Max. 

Ware 
in 




Time in 


Speed in 
Mid Ocean. 


D 










Mid Ocean. 


Ware. 


inches. 














Miles per 










b. m. 


Fathomt. 




h. m. 


bour. 






] 


rest 


16 


1000 


, , 


• • 


• • 


• • 


• • 




Mt 


2 80 


, , 














72 




1 


10 46 


, , 











P 


10 




1 


12 22 


• • 











P 


7 




1 


18 18 


«• 











P 


• • 






lfti|f-fnTif^lP'n«^ 
















-69 


17+16-88 


60 


481 


8 18 


186 


P 


• • 




-72 


26 + 16-41 


1000 


1608 


4*16 


878 


•• 


• • 




-78 


80+16-46 


600 


1687 


6 27 


812 


, , 


, , 




-80 


48 + 16-64 


160 


1806 


6 18 


867 


1 14 


12 




-72 


27 + 16-48 


100 


1868 


6 81 


838 





4 




-02 


56+16-72 


100 


1909 


6 89 


888 





6 




-77 


64+16-80 


28 


2008 


6 81 


808 


1 30 


12 




-160 


190 + 16-206 
h. m. 


160 


2000 


640 


861 





8 




I 


2 00 


Same 


Wave. 


, , 


, , 


, , 


8 




1 


1 46 


Same 


Wave. 


• • 


• • 


, , 


4 




\ 


mng.mDt.miit. 
















•Hp^uo 


68 + 16-84 


1000 


2090 


624 


826 


12 


14 




i.67 


6+16-22 


lOOf 


1660 


4 46 


847 


- • • 


• • 




'^17 


192 + 16-206 


lOOOP 


2482 


788 


881 


060 


7 




X 


124+16-140 


lOOOP 


8082 


8 64 


840 


180 


16 




64+16-80 


1000 


8642 


10 81 


847 


080 


6 














' 


No 


* 




-^ 


9 + 16-26 


800 


2619 


648 


876 


infonna- 


» • • 
















tion. 






86+16-61 


40 


2662 


7 12 


870 


do. 


• • 




8 + 16-24 


1000 


2848 


7 08 


408 


do. 


, , 




82 + 16-98 


200 


2876 


7 42 


878 


do. 


, , 




24 + 16-40 


1000 


4660 


11 44 


888 


6 00 


19 






^ 82 + 16-48 
^ 48 + 16-69 


1000 
1000 


4611 -f 
6001 


12 24 
14 24 
18 81 


871 
820 
870 


800 
1 00 
1 00 


J80 
14 




"•^ 


^^ 














mm 



^ '4 






u 



mxer 



horns 

100 
200J 



000 

Km 

ooo 

000 



190 
. 100 

130 



500 
4Q 



250 

100 
000 



tUGUST 26th— 30th, 1883. 



>uter 
epth. 



homB. 



Inks' 



POM 



100 



OOU^ 
000 

P0B3-- 
DOT]-- 



Cow^QO 

SYDJ- 
POK 40 



H0ir»2BO 
ST. plOO 

ON 



Flnt Oreat Ware. 



DifUmces 

in 
mdOoMn. 



6619 

7411 
7709 

11887 



996 
1890 

8180 



4686 
4772 



Time in 
MidOoMUL 



10190 
10848 



h. m. 

18 84 

24 61 

29 12 

22 12 



18 11 



10729 


25 


18 


10724 


26 


58 


10790 


28 


27 


10780 


25 


40 


10780 


26 


27 


10780 


26 


29 



2 21 
8 08 

18**29 



44 06 
29 64 



,10 26 
22 11 
17 28 



Speed in 
MldOoi 



Ocean. 



Miles per 
hour. 



487 



261 

847 



426 
414 
880 
418 
406 
422 



428 
170 



108 
169 



797 
469 
694 



Time of 
Mftz. Dia- 
turbance 
after Fint 
Qraat Ware. 



11. m. 

12 00 

1 00 

1 00 



12 00 
6 00 

2 'OO 

? 
88 



Max. 

Ware 

in 



Dnratian 

of 

Disturbance. 



Hours. 



over 60/ 
I 

„ 46{ 



26 
6 

9 

doubtful 

? 

2i 



? 
16 

92 



182 

88 
88 



Dept 
indica 

Formi 



850( 
106( 

94( 
178( 



580( 



262( 
205( 
264( 
242( 
264( 



264( 
800 



16C 
87€ 



940C 
8116 
6180 



CAPTAIN WHAETON ON THE SEISMIC SEA WAVES. 



149 



12. That from the great differences, caused perhaps by local circumstances, in the 
appearance of the disturbance on the various tidal diagrams, no precise or 
close comparison between them can be made, and this doubt of the identifi- 
cation of any particular wave at different places, causes much uncertainty 
in the result, as far as it relates to the speed of the waves. 

It may be remarked that, with regard to conclusion No. 5, Professor Milne, in 
his recent work ' On Earthquakes,' finds the same for such other sea waves as have 
been traced for long distances across the Pacific ; though the point of genesis has 
never been so certainly known as in this instance. 



Speed of Free WaveSy by Sir George Any. 



Depth in 


Depth in 


Geogi-aphical 


Depth in 


Depth in 


Geographical 


feet 


fathoms. 


miles per hour. 


feet. 


fathoms. 


miles per hour. 


3 


0-6 


5-8 


1,998 


333 


150 


6 


1 


8-2 


2,400 


400 


164 


12 


2 


11-6 


3,o:o 


500 


184 


18 


3 


14-2 


3,600 


600 


201 


30 


5 


18-4 


3,996 


666 


212 


42 


7 


21-0 


4,200 


700 


217 


60 


10 


26-1 


4,800 


800 


233 


78 


13 


30-0 


5,400 


900 


247 


90 


15 


31-9 


6,000 


1,000 


260 


102 


17 


33-9 


7,500 


1,250 


291 


120 


20 


36 8 


9,000 


1,500 


318 


150 


25 


41-0 


10,500 


1,750 


344 


180 


30 


44*0 


12,000 


2,000 


367 


198 


33 


46-0 


13,500 


2,250 


390 


• 240 


40 


50-3 


15,000 


2,500 


411 


300 


50 


56-5 


16,500 


2,750 


432 


360 


60 


63-8 


18,000 


3,000 


451 


420 


70 


68-9 


19,500 


3,250 


469 


• 480 


80- 


73-7 


21,000 


3,500 


487 


600 


100 


82-3 


22,500 


3,760 


504 


798 


133 


94-9 


24,000 


4,000 


520 


900 


150 


101 


25,500 


4,250 


6.36 


996 


166 


106 


27,000 


4,500 


552 


1,200 


200 


116 


28,500 


4,750 


567 


1,800 


300 


142 


30,000 


5,000 


591 



X 



150 



CAPTAIN WHAETON ON THE SEISMIC SEA WAVES. 



List of Tidal Diagrams. 





PlATB 








PUTB 


1 . Tandjong Priok (Batavi. 


a) XVII. 


19. 


Table Bay 




XXIL 


2. Ujong Pangka . . 


. XVIII. 


20. 


Moltke Harbour 


<• . 


XXIII. 


3. Ujong Sourabaya 


. XVIII. 


21. 


Orange Bay 




XXIII. 


4. Rarang Eleta . . 


. XVIII. 


22. 


Colon 


* • 


XXIII. 


5. Port Blair 


XTX. 


23. 


Socoa . . 


« . 


XXIV. 


6. Negapatam 


XIX. 


24. 


Rochefort 


• • 


XXV. 


7. Madras . . 


XIX. 


25. 


Devonport 


• • 


XXVL 


8. Vizagapatam 


XIX. 


26. 


Cherbourg • . . 


• • 


XXVIL 


9. False Point 


XIX 


27. 


Portland 


• • 


XXVL 


10. Dublat 


XX. 


28. 


Havre . . 


* • 


XXVIIL 


11, Diamond Harbour 


XX. 


•29. 


Port Adelaide . . 


* • 


XXIX. 


12. Kidderpore (Calcutta) . 


XX. 


30. 


Williamstown, Port 


Phillip 


XXIX 


13. Beypore . . 


XXI. 


31. 


Sydney . . 


• • 


XXIX. 


14. Bombay . . . . , 


XXI. 


32. 


Lyttelton 


• • 


XXX. 


15. Kurrachee 


XXI. 


33. 


Honolulu 


• • 


XXX. 


16. Aden 


XXII. 


34. 


SK Paul, Kodiak 


• « 


XXXL 


17. Port Alfred .. . 


XXII. 


35. 


Saucelito, San Francbco 


XXX r. 


18. Port Elizabeth .. 


XXII. 
Illustratr 

Flxtr 


^eCht 


irts. 




Platb 


1 . Sunda Strait, before erupi 


bion XXXII. 


3. 


Java Sea . . 


• « 


XXXI V, 


2. Sunda Strait, after erupti 


on XXXIII. 


4. Wprld .. 


• • 


XXXV, 



•^ 



W. J. L. Whaeton. 



PlaJUXm 



Noon 14 


« 


18 


20 


22 


Mid 


\ 


; 


4- 


i 


> 


\ 


1 




Auff.30^ 

Noon M- 


16 


18 


20 


22 


Mm 






























































~1 












! i 

I 












































































1 


1 

1 










































































1 




! 








































































i 
i 


! 


















































































f^ 


\ 


z' 


i^S/V 


X 


^^ 


'^ 


^ 














-- 
























A 


y 


^ 


AX' 


V 


> 


V 


^ 


r^^ 


\^ 


^^ 


-^ 


/ 
















\^ 


\ 


^ 














J* 


r^ 


^ 


r*^ 


-^ 


^Vv. 


fM^ 


»»^ 


x" 




! 

1 

1 






































s 


^, 


^r 




r^ 


/ 


.An 


f^ 
























































































































































































































































































































































































— 


_ 




















































































■■ 




























































































-- 




^ 


































































t 


I 










































































\ 


V, 










































































L 


^ 








































































W 


1 


I' 


i 


1 


G 


V 


B 


a 





2 


2 


M 


id 


2 




4 


\ 


1 


\ 


\ 


> 


n 


9 


Not 


BO 


K 


^ 


I 


6 


n 


1 


21 





2 


2 


Mi 



id Feet 
18 

r? 

16 
15 

wv 



- i:^ 



12 

It 

K) 
9 
8 

7 
G 
5 
4 
3 
2 
I 



Malby & Sons, T.ith . 



S MM 




iiat^ xvm. 




22 Mid 2 4 6 8 10 Noon 14l6»2022Mid24 6 8 10 



^Ia2"by & Sons, lith.. 



^-^'^-l-ntoa. Hep. Roy. Soc. Cr"-- 
Md 2 4 



LOCAL CIVIL TIME 



6 8 10 Noon 14 16 18 20 22 Mid 2 4 6 8 



JOC. 



»C - T T 

HO 5 


J 1 






"T 










piQ RT B! 


LAI R 1 


I ' 


'? 











-- 








Lonk. (>'<ll 


" E- 


*r FT 


^¥^>»* 


^ 


\, 




«lf 




K L 


ir/'tit" 










\ 


L_ 








^/ 


^S Mran Sea L|f 




V 














/ 


/ 


V 


'^v J' 


^ u ^^ 


1 1 1 
\ ' i 










i 




f^ 






1 T 


1 


1 ! 1 
4 u , ^- 


t - 

1 




"- 












..o. 


N E G A Ph 


! ' i 

A T A M 






! 








■5 


Long. 5M 


9"E 

j 


r ..I' 


.^ 


^ 


\ 


^v 










/^ 


i l\/\ f{ l\ n '^'^"^ SeaUeje 


Jn/Vvr" 


! ^ 


1 







r 




^\ 


/v 


J 


/ 


?ttt-.W 


1 IP" 


1 
1 


i 


















J i 1 


N? 7 

4 - . J 


! 





■ — 


- 












M A D R i 

i t • 




_ 




1 








'R 




rE. i 


« ' ^ 


— 




X, 


1 








A /^\/^\/\ Heal SeaL 


svil /^ "^x 


1 — i 








^s 








- 


ill ^-^^z:: 


i 


■ 1 ' 
1 


















1 i 




l|l?8 


.^ 


/^ 


■^ 




1 










V 1 Z A G A 1 


PAT AM ! 

j 


. 














« 1 i 


Z3^E. 


1 i 

3 *- X-4 












• 


^ ! 


-'Lj'T-\ j- 


y 








\. 








-^ 


J 


\ Mean Sea Leva 


' / Vdu 


1 










'-^^ 




j^rAi 


;/ 




1 L^'-v'^^' 


fHw 


'"■hi I 1 










































FALSE U 


= 1 N T 


: ' i 
' ' 1 




















**> 


rE. j 


5^ J. |_ 


r 


-- 


*v 














/S 1 


r--4t- 


/ 1 






> 

\ 










f 


:3/^l2 


i4-+^i 


7 


- ■■ 






\ 


\ 




y 


^ 


/ 


T ljT 

\ i4e in >eaLeve 


^^-iij 


1 
1 — -^ * 










--N — 


^ 


7^ 






""IlvtZ 


1 n^v 




i — 
















\>T 





I 



V 



i — I 



V 



IN 2 4 6 8 10 



1416l82022Mid24 6 8iON( 



LOCAL CIVIL TIME 



xttoQ.. Rep Roy. Soc. Com^- 
2 4 6 8 10 Noon 14 16 18 S) 22 Mid 2 



4 6 6 10 



Au^.28^ 



ThiteJOC. 

14 16 18 20 22 MM 



•"^ 1 1 1 d DUBLAT . .._ ___ 


'1^ Long. B'fSS" E. / V 


"Z3;"I"";^^t::: Sti t_Z-i— 


rA ^ 7 ^ T 1:7 ___T. 7__tl__ 


r^v^-- r\v\i^ i-------\-TX-t--V^--- 


\ i Mtanl ti^l of Civir fat the Yelar. \ / ^ 


1 k y V'^ \ \ \ 


i;T"i^--":-~-L^--±tt-^-i— 1-4 


, L 1 .-,-....-■- 


1?" DIAMOND HARBOUR 


L(»n J. 5»« 52" E 
1 »St /> 


^ r^ /i ^ ^ A 


:7Tr i-t-^5T .^+i-4ri^-£t 


jt r B Z-A tt\1i-t/M 


■\ ' l\ \ / * / \ 


tl : ^ ^/ 1 _.Ji__±E_4:TVt:±iTa- 


^ ' \ ill / \ 

1 \ / Mi«r L IV jl df river brittle |v4tr. \ 1 \ 


/: \ i ^ \r ^ \ 1 


1' i / \ A 1 \ 


\J 1 \ / ■ \ 


V '^' 


^■^j! KIDDERPORE 


A, Long. 5'?52"E ^"N 1 


1/ \ /^^i / \ / 


i \ / f\ / \ / 


/ H ^ f '^ \ 


■ / N 7 \ / ^1 


^ . / \ )Mnan L ?ve cF 1 ivrr «^ the Year | \ / 


Ea J "i V "tt" \7rji~i Tint: , 


1 "^ 



2 4 6 8 10 



l4l6«2022Mid2 4 6 810 



14 16 18 20 22 Md 



LOCAL CIVIL TIME 



iiryt^a, Rep Roy. Soc. Corrt 



PlaleM. 



AiJLff.27^ Au0.2S^ 

2 4 6 8 10 Noon 14 16 18 ' 20 22 Mid 2 4 6 8 10 Noon 14 « 18 10 28 Mid 



' ; 1 1 ' ■ ■ 

N? I3.| 1 B E Y P R E 


' } lorg. 51 03" i. 


^ 


i 1 .c 


■' ' Mt Ai «ri, / W ^jN- nK ^'^^•^M 




f\ 1 1 %wM 1 




N'» 1 BOMBAY 


j lor g. 4'? 51*? E. 1 


■' ' ^. -^ f\ 1 


::k^_1^, ^-T-^. It l\--\- I i ^ 


" / ^ A / \ ^^ ^ 




1 '^ ( \ ^r 1 ^ , |. 


-£- t ^^ i ff ^ iiw- k i 


: / ^ \ / ^' 


I'/i! \ J 


L ' i ■ ' 


'••S' ! KURRACHE E 1 i 


1 1 long. 4-? 2W l. ' \ 1 


■' ' M 1 7\ i 


'm/\ W\ / V r-^K 




^'1' \ f- \ ' f ' \ /l- \ 




^-^ 7 ^\-V-^X^--\-^\ + 1 


vw 


• 1 ! V|/ ^! ! i 1 1 ! 1 i 

J , 1 i , ! , ill, ; 1 , I ' , i 



2 4 6 8 n Hoon 14 16 18 20 22 Mid 2 4 6 8 10 Noon 14 16 16 20 22 Mid 



i 6 








Plate ;DCU. 



4 6 8 10 Noon 

7Fe«t 




KrcJcatocu, B^ep. B>oy. Soc. Corrv. 



16 
5 


MM 


2 




4 




& 




6 


10 


, 1 


1 


«). 
















1 












i 








3 


i 






















2 




1 


\r 


a/ 


■^ 


— »« 


A 


•^^ 


irs 


V--1 


1 




1 






















1 
1 


1 
















7 


r 


i«^i 


' 
















6 
5 

i 
3 
2 

1 


1 


" r 


















■ 


1 




















t 












































j 

1 




















1 

i 




















: 


















1 


N? 


22 


. 
















3 






















: 


2 
























1 




















1 


h 


1 






















M 


d 




2 




4 




6 




8 


iC 



KraicatocL. Rep. Roj. Soc. Corrv. 



FlodeJQOV. 



LOCAL CIVIL TIME 



S O C O A 



Long, c^oyr w. 



Aufficrt 28^ 



Mid. I E 3 4 5 6 7 8 9 10 II Noon 13 14 16 16 17 18 20 21 22 28 Mid. 



N. 


'23. 






































































A 
























\ 




















j 


/ 




\ 




















/ 




\ 


















/ 








\ 
















1 


/ 


1 

J 


\ 


\ 














J 


r 








\ 
















/ 








\ 












I 


1 












\ 












/ 


/ 








^ 


1 
\ 










/ 














\ 












/ 




















j 


















\ 








/ 


f 














^ 


1 


r^ 


1 


















\ 


\ 






/ 


















s> 
























\ 


V^ 


/ 











"Mallsy &■ Sons, T.irh . 



LOCAL CIVIL TIME 



KrakatocL. Rep. Roy. Soc. Corrt., 



Flat&XXy. 



ROCHE FORT 

Long. 0'!04'?W. 



Mt 



Auffust 28"^ 

Mid. I 2 3 4 5 6 7 6 9 10 II Noon 13 H- IS 16 17 IB 19 80 21 2 23 Mid. 



15 




24. 

\ 




















.n 


/ 
























r 


^ 


\ 
















V 








'\ 
















1 


19 


1 

1 




\ 














} 










\ 
















1 


II 




\ 










'8 

»0) 1 


f 










1 














1 




II 

m 




1 




\ 






































mi 

q 








\ 








1 
















\ 










I 






fl » 










\ 






/ 
















\ 


( 








I 






7 1 










\ 
































1 







J : 

1 

f 










\ 


\ 




/ 


















\ 














5 












\ 
























\ 






















\ 


\ 






















\ 












\ U 














\] 
























V 


1 








? 1 














































C T 
f 1 















































1 
1 











































Malbj & Sons, litK. 



KraJcatocL., jFLgz 



Mid 



K) 




w 



27. 



Mid 



''".ikaiocL. Rep Roy. Soo. Corrh. 



FlcuLeJOm. 



LOCAL CIVIL TIME 



CHERBOU RO 

Long. 0? 06? W. 



August SS^ 



Mi 
3 


N? 


26. 


\ i 


\ ^ 


V i 


5 i 


\ -i 


r e 


1 i 


1 « 


D 1 

I 


No 


on i; 


3 V 


\ W 


\ 1 


B r 


r N 


B K 


9 21 

1 


D 'I 


1 2 


E i9 


1 MM 


II ' 

1 

1 

9 1 

1 

1 

8 i 

1 

1 


/ 


\ 


r 


^ 


-i 


\ 


\ 












-\ 


\ 


t 




^ 


. 


\ 


1 




1 




7 1 

6 . — li 
I / 

5 4- 

i 1 

1/ 
\\ 

4 ^ 


L 












\ 


\ 


«8 

■0) 






/ 


\ 












\ 




\ 






3 




















\ 




/ 


/ 


















\ 






2 


1 


















V 


V 


A 






















^ 




1 


1 
L 















































^ 



Mal'brjr & Sons, lith.. 



Kriikatoa., Rep Soy. Soc. Com. 



LOCAL CIVIL TIME 



FlataJOCm. 



HAVRE 

Lo n g. 0? 0? E. 



Azigrust 29^ 



Mid. 


12 3 4-8 


( 6 7 8 9 10 1 


1 Noon 13 H- IS 16 17 18 19 20 21 22 23 MiV 


Feet 15 


1 












































14 
Q 

n 


N?28. 
























































r 
























/ 


''\ 


\ 


















/ 






\ 


V 






















\ 










II 










/ 








\ 






















\ 










n 








/ 










































a 


















' 


\ 
























\ 






ft 








/ 










































7 






j 
































































\ 
























\ 


1 




c 






/ 


























1 














\ 




5 






















\ 


, J 








1 


















4 




i 










































\ 




3 . 




/ 










































\ 


\ 




i 


/ 


















\ 


\\ 


























2 L 


i 




— . 








— 










\ 




/ 




















\ 


' - 


/ 


— 1 




















\ 


V 


1 




















^ 



TvlaJby & Sons, Lifh.. 



Flai^JOUX 



Auff.ai*^ 




IMallry & Sans, Tn'tb . 



J 



Mid Z 




I I 



1 

I : I 



ht^ 



! i i 






Mid 2 4 6 


AufftSOf 

8 » Noni 14 


E A L AN D 








1 








/ \ 


Ml 1 


iT 


r^v' 


't \r^. 


/ ■ 


1 




! 






a/ 


1 


v 


^^3 




1 








1 




! 




1 






y^ 


^4hL 




— \ ■ TV 


^w^ 


! . 1 




Mid 2 4 6 


8 K) Noon 



-i-f4 





PLat&WU. 




lfit820ZZMid24 68IO 



H 16 18 20 22 Mid 



"Mjolhy 8c Sons, lifh.. 



r:jr-,7. Rep. Roy. Soc. Corrv. 




\ 



^ 



xJcutoa. Rep Roy. Soc. Corrv. 




ir,ikatoa. Rep Roy. Soc. Conrt 




160 



i 




^*3z 



U7B 



-^--<^ 




Tioju&joav. 




Majlay & Sons, lath.. 



PART lY. 



ON THE UNUSUAL OPTICAL PHENOMENA OF THE ATMOSPHERE, 
1883-1886, INCLUDING TWILIGHT EFFECTS, CORONAL APPEAR- 
ANCES, SKY HAZE, COLOURED SUNS, MOONS, &C. 

By ike Hon. F. A. Rollo Russell and Mr. E. Douglas Archibald.* 



As this part is necessarily very long, we have found it convenient to divide it 
into sections and sub-sections; though even thereby a fresh difficulty and some 
repetition are introduced in consequence of the intimate relation subsisting between 
the various phenomena. We have, however, finally decided upon the following 
arrangement : — 

Section I. — 

(a.) Descriptions of the unusual twilight glows in various parts of the world, 
in 1883-4. 

(b.) Proximate physical cause of the unusual twilight glows. 

(c.) The blue, green, and other coloured appearances of the sun and moon. 

(d.) The sky haze and some of its effects. 

(e.) The large corona round the sun and moon, generally known as " Bishop's 
Ring." 

Section II. — General list of dates of first appearance of all the optical pheno- 
mena (with maps representing the distribution). 

* The authorship of the sections and sub-sections is indicated bj the name appended to each. 

X 2 



152 THE HON. ROLLO RUSSELL 

Section IIL — 

(a.) General geographical distribution of all the optical phenomena in space 
and time ; including also velocity of translation of '* smoke stream," 

(b.) Connection between the propagation of the sky haze and its accompanying 
optical phenomena and the general circulation of the atmosphere. 

(c.) Spread of the phenomena round the world. 

Section IV. — Diurnal and secular variation in the duration and brilliancy of the 
twilight glows, and the height above the earth of the stratum which 
caused them. 

Section V. — ^Previous analogous glow phenomena, and corresponding eruptions. 

Section VI. — Individual opinions expressed^ and hypotheses suggested, to account 
for the abnormal optical phenomena. 

Section VII. — General analysis of the connection between the unusual meteoro- 
logical phenomena of 1883-86, and the eruptions of Erakatoa in May and 
August, 1883. 



PART IV.— SECTION I. (a). 

Descriptions of the Unusual Twilight Glows in Various Parts of the 

World in 1883-84. 

By the Hon. Rollo Russell. 



introduction. 

The Committeb has been favoured with voluminous correspondence, all which has 
received careful consideration, and much has been utilized in various sections of this 
Part, but only a small portion could be quoted in extenso. The following descrip- 
tions have been selected, partly from it and partly from printed sources, as indicative 
of the nature of the phenomena in various countries, and are arranged chronologically. 



ON THE UNUSUAL TWILIGHT GLOWS. 
List op Obseevers. 



I5d 



Bishop, Rev. S. E. 
Haboraye, Mr. L. . . 
:Manlet, Rev. W. R. 
Parkbb, Mr. H., F.R. Met. 
Mbldbum, Dr. C, F.R.S 
Todd, Mr 



Anon 

Gebbeb, Dr. A. 
Tebbott, Mr., F.R.A.S 
Meteb, HeiT G. . . 
Russell, The Hon. Rollo, 
Stoddabd, Prof. 0. N. 



Soc. 



F.R. 



Met. Soc. 



Divbbs, Prof. E. 
Baadsb, Herr J. 
DupouB, M. 



Capello, Captain de Brito 
Helmholtz, Prof, von 
Hopkins, Mr. Gerabd 
Paschwitz, Dr. E. von R. 
Latabd, Mr. E. L. . • 
MoNTESSUS, M. de . . 
Ballot, Mr. John . . 



Pelaqaud, M. 
Bezold, Prof, von . 



Honolulu 

Sydney, N.S.W 

Ongole, Southern India 

Ceylon . . 

Mauritius 

Adelaide Observatory, South 

Australia . . 
Magdeburg 
Gluckstadt 

Windsor Observatory, KS.W. 
Vilsen, Hanover 
Surrey • • 
Wooster, Ohio, U.S.A. 

Japan 

Marburg 

Morges, Switzerland . . 

Lisbon . . 

Berlin . . 

Stonyhurst 

Berlin . . 

New Caledonia. . 

San Salvador, Central America 

Transvaal 

Bourbon Isle . . 
Munich . • 





Page 


September, 1883 


163 


99 91 


154 


99 99 


154 


99 99 


155 


October, 1883 


156 


99 99 


156 


November, 1883 


157 


99 99 


157 


99 99 


157 


J'ov. and Dec, 1883 


158 


99 99 99 


159 


Nov., 1883, and 


167 


Jan., 1884 




December, 1883 


168 


» »> 


169 


Dec, 1883, and 


169 


Jan., 1884 




99 9« 


169 


December, 1883 


171 


» » 


172 


» >i 


172 


January, 1884 


173 


February, 1884 


173 


March and April, 


174 


1884 




April, 1884 


177 


April, 1884 


177 



The Eev. S. E. Bishop/ says : — 

" I would note three peculiarities of the phenomenon, distinguishing it from 
ordinary sunset reflections, and unlike anything I remember to have observed 
before : — 

" (1). It appears to be a reflection from no cloud or stratum of vapour what- 



ever. 



" (2). The peculiar lurid glow, as of a distant conflagration, totally unlike our 

common sunsets. 
" (3). The very late hour to which the light was observable — ^long past the 

usual hour of total cessation of twilight, 

'* To this may be added— 

" (4). That the centre of brilliancy was more or less to the south of west." 

In a subsequent communication, Mr. Bishop tells us that the after-glow remained 
brilliant for some time, and was very bright on September 30. The haze stratum was 
visible, as a continuous sheet, at a height far above that of the highest cirrus, a slight 



• *Honololxi Safcnrday Press,' September 22, 1883. 



154 THE HON. ROLLO RUSSELL 

wavy ripple being noticeable in its structure, always perfectly transparent ; it was 
invisible except under certain conditions. A conspicuous circle of 15° to 20*^ radius 
was observed during several days, — " a misty, rippled surface of haze, with faint 
crimson hue, which at the edges of the circle gave a purplish tint against the blue 
sky." 

Mr. L. Hargrave, of Sydney, N.S.W., wrote as follows to the 'Sydney Herald' 
on September 25, 1883: — "With regard to that pink glow that has been so persistent 
at sundown lately, a casual glance will convince most persons that it is not the 
ordinary red sunset. Its bearing from S.W. to W., and even north of W., is a fatal 
objection to the Aurora Australis theory, so I hazard the opinion that volcanic dust 
is the true solution." 

On December 29 Mr. L. Hargrave wrote as follows to the * Herald ' (published 
January 2, 1884): — "I have observed the sun to set in a cloudless sky, coloured 
orange-yellow; the daylight seems to decrease for 15 or 20 minutes after sunset, 
when I observe a whitish oval patch of light at an altitude of 20° or 30° ; this rapidly 
changes in colour, becoming yellowish-purple, pink, brick-red, and crimson, the 
coloured patch of light at the same time elongates and settles rapidly down on the 
horizon, this phaae ending about 45 minutes after sunset. A second purplish patch 
then appears at about 30° altitude, the horizon turning to a brown colour. This 
second patch is more widely diffused and ita boundaries are more ill defined than the 
first one ; it changes to yellowish-purple, yellowish-red, brick-red, and crimson, 
spreading in azimuth, and settles down on the horizon in about 100 minutes after 
sunset, when the last tinge of colour disappears. 

The Rev. W. R. Manley* wrote as follows from Ongole, India : — " On September 
10, 11, and 12, the sun had a greenish-blue tinge, and was somewhat dimmed by a 
haze in the afternoons. At 4 p.m. the colour was bluish. This gradually passed into 
a greenish colour, and this in turn became tinged with yellow as the sun approached 
the horizon. As the sun sank, bands of smoky haze drifted across its disc. After 
the sun was down, bright yellow, orange, and red appeared in the west, a very deep 
red remaining for more than an hour after sunset ; whereas under ordinary conditions 
all traces of colour leave the sky in this latitude within half an hour after the sun 
disappears. At night the moon, just past the first quarter, was surrounded by a pale 
greenish halo about 30° in breadth. Aft;er sunset I observed a peculiar appearance in 
the haze which covered the sky. It was not of sufficient density to be at all visible, 
except where it reflected the direct rays of the sun. There it had a singular 
mottled appearance, with a smoky look along the borders of its denser portions, 
suggesting clouds of smoke or dust in the upper regions of the atmosphere. . . . 
Ou the evening of the 13th the sun appeared to be perfectly clear, but after it was 
below the horizon the western sky was seen to be covered with a smoky haze of a 

• * Nature,' vol. xxviii. (1883), p. 576. 



ON THE UNUSUAL TWILIGHT GLOWS. 155 

singular appearance, which became brilliantly illuminated with yellow, orange, and 
red, in the order I have mentioned, counting upward from the horizon. These sank 
one after another, leaving at last an arc of brilliant red along the west ; the inner 
portion of the segment contained by the arc being composed of orange. This disap- 
peared in turn, and the whole western sky became yellow again without any distinct 
outlines ; and this gradually deepened into red, which remained for an hour or more 
after sunset. The latter phenomenon was not unlike an ordinary sunset, except in 
brightness and duration. . . ." 

The following is an extract from the account sent us by Mr. H. Parkek, 
of Hambantota, Ceylon, referring to the various phenomena seen in Ceylon in 
September, 1883 : — '* For several evenings previous to the first green appearance 
of the sun (September 9) we had magnificent sunsets, the sky in particular 
being of most peculiar and varying shades and colours, in which delicate, beautiful, 
blue-and-reddish-purple predominated, more like the aurora borealis, but brighter 
and deeper in tone than any I have seen in the atmosphere. 

" September 24. — Just before sunset we observed the same green appearance in 
the sky and over the sun s disc as before, but not so vivid a colour. The greenness 
was very noticeable for some considerable distance around the sun, tinging even the 
surrounding clouds, which were high. The sun's disc was clearly-defined, greenish- 
yellow, but around it the green was much more distinct. . . . There was also a 
hazy appearance in the whole sky, especially noticeable just after sunset, when the 
general colour became peculiar and blue-leaden, except in the quarter where the sun 
had set, where the zodiacal light was whiter. Fully half an hour later the sky 
was still of this blue-Jeaden colour, and in the west of a dull orange glow, rather 
bright near the point of sunset. The stars afterwards were not perceptibly 
obscured. Immediately after sunset there were broad distinct palish streaks 
pointing west, beyond the boundary of the zodiacal light, apparently streaks in 
the haze. 

" On September 25 and 26 the sunsets were similar, the sun in setting 
slightly green, then a dull yellow glow near the horizon, and a blue-leaden sky long 
after sunset." 

Dr. C. Mbldrum, F.R.S.,* says : — " The optical phenomena which have been 
observed, generally presented the same features throughout, and do so still. During 
the greater part of the day the sun is surrounded by a circular patch of whitish 
silvery light, on the outer borders of which there is a brownish fringe, the diameter of 
the whole varying from 12° to 24° between 8 a.m. and 4 p.m., according to the sun's 
altitude and the state of the atmosphere. As the sun approaches the horizon the 
silvery patch extends more and more above than below him, until at length it is 
entirely above him. It then becomes greyish watery looking ; and beyond it, towards 

• * Proo. Met. Soc. of MauritiuB,' October 27, 1883. 



156 THE HON. ROLLO RUSSELL 

N. and N. W. and S. and S, W., the sky has a brownish smoky appearance down to 
the horizon. 

" At about 4 minutes after sunset the sky becomes slightly purplish at 30° to 45° 
above the point of the horizon where the sun has set. The purple soon becomes red ; 
below the red are orange and yellow ; and below them there is a bluish band, into 
which the greyish watery patch has been gradually converted. Along the horizon, to 
the extent of 30° on each side of the point of sunset, there is generally a low 
brownish-yellow band, which seems to be partly due to smoke from the sugar-mills. 
Between 23 and 26 minutes after sunset the grass, trees, &c., assume a yellowish-red 
colour. The red band, which is the most prominent, commences about 19 minutes 
after sunset at an estimated altitude of 40°, and lasts 21 minutes, its width and 
altitude decreasing until it vanishes on the horizon. At first it extends as an arc 
from W. by N. to S.W. When its upper edge has descended to 10° above the 
horizon, it becomes fiery red, and when nearer to the horizon, dark red. 

" The blue, yellow, and orange disappear in succession before the red. 

'* ^ about 10 minutes before the disappe€urance of the red band, the sky above it, 
up to 40° or 45°, begins to assume a greyish-green colour, and aft^r the red has 
disappeared this large new patch of colour, which is now inclining to yellow, is the 
only remarkable feature. 

" The upper part of the new patch becomes red about 44 minutes after sunset, at 
about 35° above the horizon. This second red band lasts 32 minutes, or till 1 hr. 
16 mins. after sunset. At first it forms an arc extending from W.N.W. to S.S.W. 
Below ft there are narrow bands of orang3 and yellow, and occasionally below them a 
bluish band, all which disappear before the red. The latter is most intense when its 
upper edge has an altitude of about 20"^ ; it then deepens into a dark red, and finally 
dies out on the horizon. 

" In the morning the phases are reversed. The first red band, which commences 
on the horizon abo\it 1 hr. 16 uiins. before sunrise, corresponds to the second red band 
in the evening, and the second red band in the morning, which commences on the 
horizon about. 39 minutes before sunrise, corresponds to the first red band in the 
evening," 

Mr. Todd, C.M.G., reported aa follows from the Observatory at Adelaide, South 
Australia, in October,* 1883 : — 

" On every clear evening dimng the month a peculiar phenomenon has been 
apparent in the western sky. Shortly after sunset a red glow will make its appear- 
ance at an altitude of about 50°, being very faint at first, but as the brightness of 
the sky^near the horizon dies away with the receding sun the red glow will exp^tnd 
downwards, becoming at the same time more brilliant, until at last the whole western 
sky will be lit up with a beautiful light, varying from a delicate pink to a very 

* * Stmons'8 Monthly Meteorological Magazine,' vol. xix. (1884), p. 78. 



ON THE UNUSUAL TWILIGHT GLOWS. 157 

intense scarlet, and presenting a very brUliant spectacle. The upper part will then 
gradually fade away until the colour is noticeable only 7^ or 8° above the horizon, at 
which time the light is at its brightest. Afterwards a secondary glow will sometimes 
make its appearance at an altitude of about 50°, and again gradually spread down- 
wards until the sky is again lit up. In the secondary phenomenon the sky is 
generally more delicate. The whole thing will fade away at about 8 p.m. This 
phenomenon has been noticed all over the S.E. portion of this continent, from Port 
Augusta to Melboiume."' 

In a great part of northern Grermany, on the evening of November 27 and early 
on the 28th, a peculiar light phenomenon was seen, of which a correspondent at 
Magdeburg wrote* : — " Already, at 5.30 a.m., a reddish glow of the twilight arc was 
seen in the S.S.E., which quickly augmented in breadth and height ; the splendour 
of coloimg was not quite equal to that of the preceding evening, but towards 6.30 the 
whole sky, from N.E. to S., seemed to be bathed in shining pm-ple. At 6.45 the 
carmine tint predominated, which appeared in a very distinctly marked flat arc. At 
7 a.m. the more elevated arc was of so pale a yellow brightness that one might sup- 
pose that the sun had already risen. . . . The sun rose at 7.43. On the evening 
of November 27 the time of the visibility of the arc was 2 hrs. 13 mins. ; on the 
morning of the 28th also 2 hrs. 13 mins." 

Herr Dr. A. Gekb£R wrote* from GlQckstadt as follows : — 

" The phenomenon was most fiilly developed here, as elsewhere, from November 26 
to December 1, but did not suddenly cease at the latter date, for there was an 
unusual colour in the sky for many days, more particularly before sunrise. The 
display of November 29 was the grandest and most manifold, and I give a description 
as exactly as possible of this one, as its overwhelming magnificence still presents 
itself to me as if it had been yesterday. When the sun had set about a quarter of 
an hour there was remarkably little red (or ordinary) after-glow, yet I had observed 
a remarkably yellow bow in the south, about 10° above the horizon. Soon — ^that is, 
after about 10 minutes more, when it was at least half-past fom- — ^this arc rose pretty 
quickly, extended itself aU over the east and up to and beyond the zenith. The 
sailors declared, * Sir, that is the Northern Lights 1 ' and I thought I had never seen 
Northern Lights in greater splendour. After 5 minutes more the light had faded, 
though not vanished, in the east and south, and the finest pm-ple-red rose up in the 
S.W. ; one could imagine oneself in Fairyland. The S.W. sky was bathed in an 
immense sea of light red and orange, and till more than 1^ hours after sunset the 
colouring of the sky was much more intense than it is half»an-hour after a very fine 
sunset in ordinary conditions." 

Mr. John Tebbutt, F.R.A.S., of Windsor Observatory, N.S.W., wrote as 
foUowst on November 15, 1883 : — 

• * Met. Zeitschrift,' vol. i., p. 185. 
t * Sydney Herald.* 



158 THE HON. ROLLO RUSSELL 

**The appearance presented by our evening skies for some weeks past has been 
the subject of general remark. 

"Last evening, November 14, the sky was almost cloudless after sunset, and the 
usual brick-red light again made its appearance along the west-south-west horizon. 
It was reflected apparently from an almost invisible and gauze-like cloud in the 
higher regions of the atmosphere. About 7 o'clock the red glow was at its maximum, 
when a solitary cloud, whose apparent siuface did not exceed ten square d^rees, 
presented itself above it at an altitude of 25°, This cloud, which was at first white, 
quickly changed to a beautiful green, its borders being of a deeper tint Of all the 
cloud phenomena that I have witnessed, it was one of the most remarkable. It 
retained its green colour for the space of about 10 minutes, being aU the time subject 
to much internal commotion. It soon afterwards resolved itself into several cloudlets 
and finally disappeared. Two or three other small clouds were visible at the same 
time, and about the same altitude above the northern horizon ; but these were of a 
grey colour throughout. The eastern sky about the moon was of that deep blue 
which is frequently observed to surround her when rising during the winter opposi- 
tions. Shortly after the dispersion of the green cloud the ruddy glow gave place to 
the ordinary pale gray of the twilight, but by half-paat seven o'clock the western 
sky became diffused with red, but this time of a clearer and more aurora-like tint. 
It did not appear, as in the former case, to be reflected from hazy cloud, and it 
extended much higher in the sky, This repetition of the ruddy glow on the same 
evening is a phenomenon which I had witnessed on several occasions during the 
present month. I remember that many years ago (probably twenty-five) a somewhat 
similar patch of red light used to make its appearance regularly after sunset in the 
west-north-west. This phenomenon occurred previously to the commencement of my 
regular meteorological observations in 1863, and was, I think, contemporaneous with 
a very dry winter. 

** That the present ruddy akies are not merely a local phenomenon is obvious 
from the fact that during the past three months they have been regularly observed 
over a considerable portion of the Indian Ocean." 

Herr G. Meyer wrote,* at the end of December, as follows : — 

" The twilight phenomena occurred here from the 26th of November, and lasted 
till 5.45 p.m. On the last days of November their course was such that at first a 
strong evening redness developed itself, which lasted till 4.30 (and similarly a moruing 
redness). At this time the whole sky shone with a yellowish colour, and from 4.45 a 
purplish glow developed itself, which attained its maximum at 5, and sank down to 
the horizon till 5.30. On other days these periods were not so sharply distinguish- 
able. On December 19 the phenomenon was absent. On December 5 the moon had 
a large circular corona. The sky is, in a striking degree, never pure, even with a 

• *Met. Zeitschrift,' vol. i., p. 161. 



ON THE UNUSUAL TWILIGHT GLOWS. 159 

high barometer and calm weather ; in weather otherwise clear the sun is surrounded 
with a sheen." 

The following are local notes taken in Surrey by the Hon. F. A. Rollo Russell 
(MS. Register) :— 

*' The first sunset which showed any effects of a very striking or extraordinary 
character was on November 9, 1883 ; but, on referring to private notes taken daily 
during the summer and autumn, I find that as early as September 8 a ' fine red 
sunset with after-glow' is mentioned, and this is worth remarking, because I had 
never previously used the expression * after-glow.' 

" On September 9 a * great succession of small cirrus-like masses ' was noted, 
' and fibres, clearly marked ; very high small cirro-cumulus, vastly higher than the 
cirrus, also high. Beautiful rainbow colours in cirrus and cirro-cumulus near the sun. 
All coming from W. against surface wind.' The remarkable feature in this condition 
was the great elevation of the cirro-cumulus above the cirrus, and the colours were 
certainly quite imcommon. 

" On September 26 there were ' light pink cirrus stripes ' at sunset. 

*' On October 3 there was a * red and yellow sunset.' 

" On October 20 there was a * fine reddish sunset, with bright isolated cloud 
and slight low cirrus.' 

" On October 21a' fine reddish and orange sunset.' 

" On October 22 ' simset in bath of cirrus ; halo effect, red. Rest of sky 
clear.' 

" On October 23 a ' clear sky, but white mistiness on horizon ' at sunset. 

*' On October 27 ' fine-weather sunset ; some streaks of soft delicate cirrus in 
irregular patches, turning fine pink at sunset ; glow from horizon.' 

" On November 8 a ' fine sunset, with straight horizontal lines of cirrus (?) and 
very slight bank. Long after sunset, and till nearly dark, a pink glow fi:om some 
very high filmy cirrus." 

The foDowing is transcribed fi^om the notes taken on November 9 : — " Series of 
ripple cirrus in web-Uke uncrossed strise, transverse ; well-defined morsels of high 
cixro-cumulus ; some cirro-stratus. At 7.30 a.m. there was some high pink filmy 
cirrus, Uke last night. 11.20 a.m. — Blue sky, but some large patches of very high 
cirro-cumulus, one overhead ; smallest fleeces ; part consisting of re-curved waves or 
bars, smalL . . . Heavy shower 1.50 to 2.5 p.m. Fine after this shower ; sky 
cleared of cirrus and cirro-cumulus, and general appearance quiet. . . Sun set in 
very slight haze bank or cirrus ; remarkable whitey-greenish opalescence above sun 
at sunset. About 15 minutes after sunset the sky in W.S.W., from near the horizon 
up to about 45°, was of a briUiant but delicate pink. Below this a very curious 
opalescent shining green and sUghtly greenish-white, the pink opalescence going 
off into bronze-yellow, and that to the green tint. The coloured portion of the 

y2 



160 THE HON. ROLLO RUSSELL 

sky spread out like a sheaf from the horizon, and apparently consisted of a very 
high thin filmy cirrus disposed in transverse bands, or ripples, close together, and 
very delicate in form, outline, and tint. At sunset some morsels of cirro-cumulus 
were lighted up with a light red fading to a deep red, but this soon passed off. 
What remained seemed not to belong to clouds, but to glow of itself, like some 
super-atmospheric film. The bright pink colour continued, and even increased in 
brightness, and at 5 o'clock cast a fine glow over the east hills and on objects 
exposed to it. The moon was shining brightly. The colour now began slowly to 
recede towards the horizon from the part most nearly overhead, and left a clearly 
visible filmy ripple of cirrus (apparently) of a soft grey. When, however, at 5.25, 
the greater part of the colour was gone, and it remained bright only near the horizon, 
it began to grow again, and in a short time (5.32) the whole extent of the film was 
again glowing bright pink, producing a very striking effect in contrast with the 
silvery moon, dark sky, and bright stars in the north and east. It was now almost 
dark, except for the moonlight and the cirrus glow. The pink light then slowly 
withdrew towards the horizon, remaining bright and deep-coloured there till 5.50. 
At 5.58 the last pink colour disappeared.' The sight was, altogether, a very extra- 
ordinary one, and unlike any in the writer's experience. It was remarkable, first, for 
the light filmy character of the cloud (if cloud it was) ; next, for the wavy form of 

Fig. 13. — Diagram of Sunset Colours 



Blue -^ ^ -~^^^^\/:_L^^~ '-^ Slue 

Sky ^^'^^^A^'^'^^-^ll .^^mZ^^ Ski/ 

V WAtU ■ -w^ 

Bright opalescent Jillout 

^^^^^ andWute Grten 

Gtttn Bright Green Green 

Opalescent 
Green ha^e Pink 

HORIZON__— HORIZ ON 

SUN C\ 

the clo\id ; thirdly, for the bright green glow near the place where the sun set, and 
the strange yellow light above the green ; fourthly, for the very long endurance of 



ON THE UNUSUAL TWILIGHT GLOWS. 161 

the whole phenomenon. It was supposed to be due to cirrus or a high kind of cloud, 
because (l) similar clouds stretched in long streaks southwards and over the S.E. 
horizon, and the glow remained long in these streaks ; (2) when the light retired it 
remained visible as silvery-grey cloud ripples before the second after-glow re-kindled 
it ; (3) because the colour became (but very graduaUy) darker as time went on, and 
the recessions towards the west followed the sun. There was no apparent movement 
of the cloud during the time of the display ; the form remained the same throughout, 
and was distinguished by the clear demarcation of the film towards W. and E., the 
cessation of the cloud and the glow towards the zenith, and the long streaks stretch- 
ing apparently horizontally near the horizon. The sunset light of the sun was 
peculiarly yellow. The ripples of the luminous film were transverse to the 
sun's rays. 

" On November 10, at 6.20 a.m., there was ' a pink sunrise light in the extreme 
east,' the rest of the sky being cloudy. During the afternoon, about 3.30 p.m., and 
later, * a very thin high cirrus ripple haze became visible in parts of the sky, especially 
S.W. About 4.32 this became more distinct as it began to glow with the light of 
the clear sunset (4.18), and became bright pink, lasting till 5.10. As the light faded 
off it, it entirely disappeared in the deep blue sky. The ripple was very small, close, 
and fine, and lay to the left, or south of the place of sunset, up to about 25° from 
the horizon.* 

" On November 11 there was pink cirrus in the E. at 6.10 a.m. 

*' On November 17 the simset was clear. 

" On November 19 there was a ' clear sunset with white mist.' 

" On November 23 there was * sunset in cirro-stratus or cirrus bath.' 

" On November 24, ^ after sunset yellowish-green striae in W.' 

" On November 25, * sunset in amorphous indistinguishable cirro-stratus or cirrus 
haze. Green light above sunset, and bright greenish-white growing from about 
10 minutes after sunset. Above the greenish -white pale red or pink. Lasted about 
45 minutes after sunset. The sky shone somewhat as on November 9, but much more 
feebly.' 

" On November 26 similar phenomena occurred more strongly, and lasted nearly 
an hour. Also on November 27, lasting till 5.20. 

"On November 28 the glow began about 25 minutes after sunset, and was 
succeeded by a faint brass-coloured secondary glow. 

" On November 29 a similar glow was seen through breaks in the clouds, and 
the newspapers gave an account of an extraordinary redness in the sky from 5.30 to 
7.30 a.m. 

" On November 30, at 6.5 a.m., there was a fine deep red glow in the E. This 
spread quickly upwards, and had turned yeUow by 6.40. At 6.24 the faint redness 
extended to the zenith. There was no cirrus visible, but some cirro-cumulus remained, 
tipped with duU red from 6.5 to 7.44, when the sun rose. 



162 THE HON. ROLLO RUSSELL 

" On December 4, when the sky was again clear, the first redness appeared in 
the E. at 6.5, and at 6.10 'was quite bright, like the reflection of a fire.' It 
appeared continuous and without defined shape. By 6.30 the red had slowly changed 
to a saffron colour, and being seen less in perspective, seeraed less concentrated. The 
reflecting matter, or a part of it, was now seen to consist of ill-detined streaks and 
patches of misty cloud of some sort, in which, after long watching, no motion oould 
be detected. At 6.45 some of these streaks were illuminated nearly overhead south- 
wards of a pale straw colour and bluish-white, and their outlines were distinct. Most 
of the streaks stretched about W.S.W. to E.N.E., and towards the N.E, the 
appearance was like a fretwork of the lightest wavy mist. From 6.30 to 6.50 the 
glow was of a sickly yellowish-green, with a pale pink towards the zenith, and a 
rather ghastly white glare below. At 6.53 a second glow, much brighter than the 
first, appeared in the E.S.E., of a deep red colour, quickly turning to orange. This 
glow was in a bank or arc much better defined along the top than the first. At 
7.10 it had turned quite yellow, and had grown up to about 15°. At 7.16 the 
last star disappeared m the bright light which was now cast on all objects towards the 
W. ; the clear sky, as the light touched the thin high mist, appearing progressively 
veiled. Just before the advent of the second glow the thin cloud streaks had nearly 
vanished, but as this new light grew and changed to bright yellow they became again 
illuminated. At 7.12 the upper part of arc No. 2 was yellow, with a greenish-white 
central part below. At 7.20 the part below the arc, and along the horizon south and 
north for some distance, was a peculiar steely bluish-yellow, and the upper (at an 
altitude of about 50°) pink. These effects slowly diminished, but the steel colour 
remained tiU sunrise. At 7.23 the sky overhead and towards the W. was faint pink, 
with large billowy streaks and patches like murky cirrus, without fibrous structure. 
This cloudy appearance was sufficient to hide the blue sky, when the cloudy matter 
wafi illuminated from below ; but in fuD daylight only faint traces remained. At 
7.50, and for some time after, this cloudiness was again made plainly visible by the 
rising sun, as by the first and second glow. Twelve minutes' careful watching failed to 
discover in them any uniform progressive motion, though their shape slightly changed. 
The sun rose at 7.55, of a red colour, but in about half an hour was pale steely-bluish 
white, and surrounded by a silver- white sky, with a slight bluish tinge. During the 
day the billowy high mist was faintly visible, but the sky was bright blue. As the 
sun was setting (3.53) this high haze became so white by reflection that the sky 
looked quite clouded with it. Nothing otherwise remarkable appeared till 4.12, when 
it was evident the phenomenon would recur ; the central spot above the sun's place 
being bright steel or lead colour, and the parts round it a metallic pink, this has 
been the usual preliminary. The sky in the east was rosy. The rose colour quickly 
passed over towards the west, and about 4.20 the whole sky between the western 
horizon and the zenith was flushed with red. At this stage the forms of the haze- 
billows and streaks seemed to be lost in the uniform rosy glow ; this glow slowly sank 



ON THE UNUSUAL TWILIGHT GLOWS. 163 

down to the horizon as usual. At 4.25, or thereabouts, the crescent moon appeared 
blue in this pink haze, but in a few minutes was left behind and appeared much as 
usual. The small stormy scud from N. was lighted up pink against a deep blue and 
green sky towards the E. and overhead, and in the S,W., near the moon. As the 
glow sank westwards the sky seemed perfectly clear, without a trace of the billowy 
haze. At 4.35 the bank of light was very bright. About 4.45 it was lost to view 
behind low clouds; as it approa)3hed the horizon the sky again became mottled with the 
reflecting haze, which assumed a straw-coloured tint. This pale light again sank 
westward and vanished soon after 5 ; the moon and stars gave no indication of a haze 
canopy. It seemed to be without motion, and was disposed in ver}^ large billows, 
their length lying about S.W. to N.E. on both sides of the glow, but crossed in some 
parts by a thick streak nearly at right angles. 

"On December 5, * exactly at 6.5 a.m. the first faint red blush grew up 
quickly from the E,S,E., and in 7 or 8 minutes had increased largely in brightness 
and extent. The night was very fine and clear and the soft crimson .glow banging 
above the horizon in the darkness produced an interesting efiect. It grew rapidly up 
towards the zenith, and at 6.18 formed an arc, of which the highest point was about 
40** from the horizon. After this it quickly changed to orange and yellow, and the 
colours went off. The arc was more southerly than yesterday, and the peculiar light 
reached from S.S.W. to N.N.E. At 6.55 the second glow began ; and rising up quickly, 
produced a fine red arc, less bright than that of yesterday morning. At 7.6 the arc 
was olive-green below, yellow in the central, and pink in the outer parts, and hardly 
any cloud structure could be discerned. What there was, however, seemed to 
resemble the film of yesterday. The upper edge of the glow, as it advanced, was 
pretty well marked, and at 7.12 it crossed the zenith and passed north-westwards, 
covering a bright star in that direction with a thin pink veil, This star continued 
visible till 7.21. The sky after this time was pale yellow, and little of an uncommon 
character remained, except the greenish light in the east, Sunrise, 7.51, red sun, 
turning sUvery-white later, Sunset, 3.50, in hazy striae. At 4.15 yellow glow 
appearance began and went through usual changes, The light was pink overhead 
about 4.25, and the margin (ulterior) passed over about 4,26. The glow grew more 
and more red, as usual, in sinking down, exhibited spokes of rays, and disappeared at 
4.45. The second illumination was brightest about 5.5 and disappeared a few minutes 
later. At 430 the moon looked blue, like yesterday, in a pink haze. The horizon 
was misty. The crescent moon shone all the evening with a greenish light. 

" On December 7 it was remarked that the reflecting matter in the west after 
sunset first shone with the rays of the setting sun between 20 and 29 minutes later 
than the cirrus above which it floated. 

" On December ] 1 the sky was perfectly clear and cloudless about an hour before 
sunrise, except a little detached scud. At 7.21 a.m., as the light of the primary 
glow spread to the zenith, the sky was seen to be striped with very high filmy streaks 



164 THE HON. ROLLO RUSSELL 

in the S.E. At 7.32 this appearance extended over the N.W. Obtaining a good 
view of the streaks in the S.E., I tried to discover their motion. After about 10 
minutes' watching, one of them showed a translation from W.N.W. of about half an 
apparent solar diameter in that time. At 7.35 and 7.40, the whole sky being covered 
with these long thin stripes, like the " billows " of a few days before, but not so wide, 
it was found that they extended on aU sides from south to north or S. by W. to K. 
by E. One point seemed worth special notice. Those' in the extreme west, that is, 
10° or so above the horizon, as weU as in the east, did not appear, like ordinary cirrus 
lines, to radiate from a point on tbe horizon. On the contrary, they were all seen 
CO be lying in the same direction, and the stripe furthest to the west gave nearly 
as good an idea of its true direction as a stripe overhead. The eye made the 
necessary allowance for such appearance of convergence as there was ; and they were 
at once seen to be parallel. At 1 p.m. the streaks of sky-haze reappeared, stretching 
from S.S.W. to N.N.E., and were watched without any motion showing itself, though 
when looked at after the lapse of 15 or 20 minutes they seemed to have moved a little 
transversely eastwards. Their very indefinite appearance in the daytime made exact 
observation difficult, and at times the strong sunshine seemed to obliterate them 
altogether. . . . At 2 p.m. a stripe of upper haze in the S.S,E. was watched 
for 10 minutes, and no motion discovered, either transverse or longitudinal. The 
stripes were observed through dark glasses, which increased their visibility. At 4. 1 5 
green spot about 10** above horizon. Pink up to and beyond zenith, and on both 
sides. Small cirri from sunset till 4.10 pink, then light dusky green. Whole sky at 
4.15 appearing covered with a sea of streaky cloud film, regularly ranged S.S.W. to 
N.N.E. ; no appearance of a radiant point. At 4.20 spot of green being closed in by 
bright pink all over western sky ; 4.23, pink seemed to pass zenith. . . . At 
4.30 pink edge about 22° from horizon. Green sunk beyond horizon. At 4.36 pink, 
about 15^ Sky blue. At 4.41 edge of red glow about 10° above horizon. Sky 
beginning to be lighted up from below, and to appear cloudy again. At 4,48, blood- 
red to about 7°, Cirri in E. peculiar dull pink. Moon very slightly bluish. 4.55 
last red disappeared. Second glow just past zenith. Usual phenomena of second 
glow, like first over again, but less bright. At 5.18 red arc very fine. Almost gone 
5.30. Just visible 5.33. 

" On December 15 there was ^ a yellow glow in the S.E. at 6.18 a.m., which grew up 
as usual. Very fine clear sky with bright greenish moon (full) in the W. Not the 
slightest halo or corona by the moon during night or morning. Greenish light above 
sun at sunrise, kc. Sky now (7.40) seems to be streaked with haze billows (length 
S.S*W. to N.N.E.) as on previous days. The western sky showed this marking very 
clearly at this time, but it quickly became less and less visible towards sunrise. It 
remained visible, however, over the S.E. for a long time, and after sunrise for at least 
three quarters of an hour. The western sky, at 7.40, looked as if covered with a 
cloud of a streaky cirrus character, only more regulai'ly disposed in bands, like a great 



ON THE UNUSUAL TWILIGHT GLOWS. 165 

ocean covered with regular billows. There were, however, some spaces clear. At 8 
all this (in the west) had melted into blue again. From 8 to 8.30 a.m. I watched the 
distinct streaks in the S.S.E., the branches of an oak giving the means of discovering 
motion in any direction. Half an hour's watchiug failed altogether in detecting the 
slightest general movement, though there was a slight change in the breadth of one 
of the streaks. After the sun had risen about a quarter of an hour, the stripes in 
the W.N.W. again grew quite distinct, but did not .obliterate the blue sky as 
before." 

In fiirther daily notes on the sky-phenomena, the following points may be 
mentioned : — 

'* On December 21, the clouds remained red 1 hr. 15 mins. after sunset. At 4.22 
p.m. the cloudy matter or high haze very unexpectedly appeared in the west and 
nearly overhead, the sky not having seemed transparent enough to show it. It was 
in the form of a hazy, white ripple, the waves close together and regularly disposed, 
but not all in the same direction in different parts of the sky. Some were stretched 
from S.W. to N.E., others from W. to E. and S.S.W. to N.N.E. 

** On December 23, the evening glow was exceedingly beautiful, exhibiting radiant 
spokes. About 4.30 the clear sky between the zenith and the horizon became as if 
veiled with a very delicate, thin, structiu*ele8S mist, which completely hid the blue. 
This was at first greenish-yellow below, and then turned to a very fine amber below 
and pink above. At about 4.35 the glow may have been at its highest point, about 
35*^ or 40° above the horizon. It sank below the horizon at about 4.52. At about 
5.5 the secondary glow extended to the zenith, and remained an exquisite faint pink 
(near the horizon) till 5.25. On both sides the sky near the horizon was clear blue 
or green. 

" On the last days of December, which were foggy and cloudy, a pinkish light 
affected the mist as early as 7.30 a.m., and sometimes after sunset. 

'* The glow continued during January. On January 24, the hazy stripes were 
very plain over the western sky, and during the whole morning, in the neighbourhood 
of the sun, making a sort of sheen close to the sun ; their motion was imperceptible 
in ten minutes' watching. After sunset the ulterior margin of the glow passed 
overhead about 4.57 ; set at 5.20. Second glow about 25° high at 5.40. 

'* There was a marked diminution of all the effects at the end of January, The 
sun was sxnrounded during the day by a brownish-pink, faint, and ill-defined circle, 
and between this and the sun there was a bluish-white sheen or glare. 

" In February, the duration and intensity of the glow decreased further, and it 
was of a yellow colom*, or faint green and pink. 

*' On March 6, there was a slight repetition of the sky-illiunination, lasting only 
30 minutes, but during March the glare completely vanished, and no illumination 
whatever appeared in a clear sky after sunset. During the remainder of the year 
the siuisets were uncommonly free from colour, even promising skies turning grey 



166 THE HON. ROLLO RUSSELL 

Boon after sunset, and no redness of an ordinary character remaining along the 
horizon after sunset, except on a few evenings and in a few localities." 

Local Notes taken at San Remo, Italy, and Cannes, France, from January 5 to 
January 14, 1884, by the same observer : — 

'' On January 5 and 6, the glow was visible but not striking at San Remo. The 
hazy streaks lay from S. W. to N.E. 

" On January 7, there was a fine yellow after-glow, lasting about an hour. 

** On January 8, there was a fine cleax sunset with the sky-haze very distinct in 
billows or streaks exactly as in England, but very faint, S.W. to N.K Duration 
about an hour, chiefly yellow. 

" On January 9, the sunrise was extremely clear and fine. The time from strong 
•twilight to sunrise was 61 minutes, from the primary glow at about 5*^ to sunrise 
41 minutes. Before sunset the streaks again appeared in an intensely dear blue 
sky, about S.W. by W. to N.E. by K About 10 minutes after sunset the sky was 
beautifully rosy in the east and slightly rosy in the north, and towards the zenith 
in the west. In the west bright peacock green. At 23 minutes past sunset the upper 
margin of the pink passed the zenith. The west now turned bright yellow. At 
35 minutes past sunset the red was lost in the yellow western sky. At 37 minutes 
the edge was about 10^ above the horizon. A beautifiU secondary glow appeared at 
55 minutes, the evening star looking blue through the pink haze. 

*' On January 10, the air, sky, and horizon were perfectly clear. At 22 minutes 
before sunrise a beautiful piu*plish^pink film extended between about 40° above the 
eastern horizon and the zenith. Below this in the east was a green sky, and along 
the horizon an orange band, which no doubt was the ordinary effulgence of simrise. 
All the sky colour soon went except the strange green i^ the east. The sun rose like 
a gush of white-hot iron, instantaneously brilliant, fron^ the sea line. Corsica, over 
100 miles distant, was very clearly defined. The streaks in the sky appeared as 
usual before sunrise, and were lying StW. by W» to N.E. by K, obliquely to the rays 
of the rising sun. 

" At sunset all the atmospheric conditions were absolutely perfect for separating 
the sky-glow from all accidental interference. The sky was transparent and 
cloudlesa After sunset came the bluish-white arc. At about 22 minutes after 
sunset the condition was as follows : — Orange ordinary glow in S.W., near 
horizon ; above this a greenish-bluish white arc, then a beautifrd yellow band ; then 
up to the zenith a very beautiful lUac tint. AU these colomrs were of extr^ne soft- 
ness, and though not so striking as in some of the sunsets in December, in point of 
beauty they were quite unsurpassable, and of superb magnificence in their further 
progress. The pink, piu^ple, or lilac, now retired in the most steady and regular 
manner towards the horizon, and were visible to the end ; 35 minutes after sunset the 
arc was formed of the inner part, which from steel-blue had gone through olive-green 



ON THE UNUSUAL TWILIGHT GLOWS. 1C7 

to yellow, the middle, yellow, and the outer, purple. Through the fringe of this, 
Venufl shone beautifully. The horizon (about a quarter of the circle) was deep yellow. 
The purple part being the smallest was flooded, except at the edge, by the orange 
light, which shone in a grand arc for a long time with great splendour, casting 
shadows. In about 54 minutes the primary glow was gone, having sunk in a deep 
red band. The eastern sky during the first part of the display was a glorious deep 
blue, then very dark purple-blue, and lastly only illumined by the silver moon. 
The secondary glow was very visible, as the thinnest pink or lilac film, 1 hour after 
sunset. It disappeared on the horizon about 1 hr. 20 mins. after sunset. The sky 
streaks were less distinct than usual 

" On January 11, the simrise was not so fine, but the sunset (at Cannes) gave 
magnificent e£Gects. About 22 minutes after sunset the ulterior margin (well-mai'ked) 
of the primary passed overhead, leaving the east deep azure. As the green gave 
way to the yellow, the yeUow to pink and violet, and the final deep red band shone 
out by itself from above the Esterel Hills, the most enchanting effects succeeded each 
other in slow and regular order. Last red, 50 minutes ; secondary glow 30° above 
the west horizon at 65 minutes past sunset, but had been very apparent up to and 
beyond the zenith while the primary was still bright, its first effect being a curious 
discoloration of the eastern sky. At 70 minutes, very fine, dull red, in west ; just 
disappearing behind hills 82 minutes after sunset. The glows were seen on the 
following days, and in travelling through France on the 14th, 15th, and 16th." 

Prof. O. N. Stoddakd/* of Wooster, Ohio, writes as follows respecting the sunset 
phenomena at that place : — 

" The main features of the exhibition here have been the crimson glow— the 
first and after-glow with other accompanying colours, closely corresponding with 
those in England and the continent of Europe. I have on record seven cases, which 
were nearly all that the weather would permit one to see. These occurred on 
November 27, December 9, 10, 25, 28, and January 13 and 17. The first and second 
glows have extended in two or three instances, though faintly, to the zenith, and the 
first has occasionally been reflected on the eastern sky. On December 28, the most 
brilliant exhibition in the series, an arc was formed in the east, the colours red and 
yeUowish-green, very soft, and much blended. The crimson glow on the sky flooded 
the western sides of buildings with an unearthly light, and cast faint shadows across 
the snow. The appearance of the after-glow, when the sun had reached a certain 
angle, fiavours the view that it is a reflection of the first. K this be true, it is not 
necessary to admit so great an elevation of the reflecting matter above the earth. . . 
The glow has been seen without the slightest trace of cirrus clouds behind it. Three 
times faint ribbon-like stripes of cirri appeared in the first glow, but in the second 
the gorgeous crimson has generally been projected against the clear blue sky." 

* 'Nature,' vol. xxix. (1884), p. 355. 
z 2 



168 THE HON. ROLLO RUSSELL 

Prof. E. Divers, of Japan, says,* in a letter dated December 12, 1883 : — " On 
some days there is round the sun, even whUe it is still high, a considerable area 
of silvery glare, 40° to 50° in diameter, and bordered by a lurid reddish-brown or 
purplish-brown halo. A similar lurid turbidity lies on the horizon, and as the sun 
descends the halo blends with this below, while above the sim it attenuates and 
disappears, the silvery glare remaining undiminished. When the sun sets there is 
stiU a nearly circular area of this intense glare, with a diameter of about 12°, On 
other days there is, before sunset only, a thin silvery light round the sun, diffusing 
away from it, and only about and after the setting is the more defined area of strong 
light strikingly visible, and on these days the horizon also shows little of the dull 
redness mentioned above. Besides the above-mentioned peculiarities the sun 
preserves its whiteness much more than usual, so as to be only golden-orange when 
setting. Now follow the more remarkable phenomena. The white glare, or patch 
of silvery light, gradually sets, spreading out along the horizon as it does so, and 
passing through the sunset colours until little more than a red line one or two 
degrees deep remains. This happens at about 20 minutes after sunset. At this 
moment, on the grey curtain of twilight appears a white luminosity, which rapidly 
intensifies over the sunset and shades away over almost half the visible hemisphere. 
The brightness over the sunset becomes vividly brilliant, and at the same time 
delicately coloured. Over a somewhat depressed circular area, about 12° high and 
15° broad, it assumes a pale green tint. Above this comes an equally dazzling pale 
yellow-orange, and again above this a soft rose colom* melts away to the zenith. The 
revival of the light, or return from commencing twilight, is peculiarly striking. 
Buildings become brilliantly illuminated, and strong shadows are cast. All this 
out-glow occurs in no more than 5 minutes, and then continues for about a 
quarter of an hour ; but the brilliancy gradually contracts in area and sets with a 
magnificent display of sunset colours, reaching about 120° round the horizon, until, 
by 50 minutes aft)er sunset, this light also has gone down to a red line of about 
2° elevation. I should not have omitted to say that the green light passes to 
yellow. 

*' By this time night has fairly well come in the eastern half of the heavens, but 
already another but more delicate silvery whitening begins to show itself on the 
western curtain ; and this also diffuses very rapidly up to the zenith and round to 
north and south. It also then goes through a process of contracting, intensifying to 
considerable brightness, and gradually passing through the sunset colours. Night is 
now full — with or without moonlight, according to date — and from the west, or 
rather from a point well to the north of it, spreads a delicate but brilliant light, 
having an almost perfect resemblance to the bimiing of a vast distant city. The 
last crimson light of this reflection does not disappear till an hour and a half after 



sunset." 



* *Natare; vol. xx\x. (1884), p» 285. 



ON THE UNUSUAL TWILIGHT GLOWS. 169 

Herr J. Baader remarks* as follows, respecting a morning twilight at Marburg, 
in Steiermark : — '* When I woke on December 1 towards 6 o'clock, I observed at once, 
through my window towards the west, an intense red ; mountain and valley were 
covered with a marvellous glow. The vineyards towards north and east, the 
Matzelgebirge, south and north-west, the snow-covered hills of Bacheon and Posruck, 
all was, including the whole sky, a sea of fire, the f<^ in the valleys like molten 
metal. About 6.45, on going out I saw, to my great astonishment, in the E.N.E, an 
arc spanning the sky, which was yellowish and in parts pure blue, up to about 20^ 
The boundary of the coloured space was sharply marked off from the blue firmament, 
and moved with great speed towards W.S.W., although there was hardly a light 
current of air. In a short time nearly the whole sky up to the zenith was free 
from the phenomenon — only in the far west a sharply defined arc appeared for a 
short time." 

M, DuFOUR, in his pamphlet,t states the following facts regarding the twilight 
glows as seen at Merges, in Switzerland : — " They were first noticed in Switzerland 
on November 26 ; they diminished considerably at the beginning of December, 
increased greatly at the end of December, and were remarkable during the whole of 
January. They diminished dining February, but did not altc^ther vanish ; till the 
end of 1884, when the weather was favourable, the sky was illuminated in the 
morning and evening as by an aurora borealis. 

" On January 10, 1884, the redness began to appear at 6 a.m. ; at 6.30 the glow 
was in all its splendoiu* ; at 6.45 it began to diminish ; at 7.5 there was a green zone 
above the mountains, red higher up ; at 7.15 the zone near the horizon was livid 
green, the red above it ; at 7.20 there was no appreciable redness. 

** In the evening, at 5 p jn., the sky was yellow"; at 5.6 the red was conspicuous ; 
at 5.40 shadows were cast ; at 6.15 the redness disappeared. 

**0n January 11, at 5 p.m., the sky was yellow ; at 5.23 aU the horizon was 
coloured red, even in the east ; at 5.25 there was a carmine zone in the west ; at 5.36 
the red became very intense in the west, in a sector of which the sun seemed to 
occupy the centre ; at 5.45 the Alps lost their red colour, but there was intense glow 
in the west ; at 6.16 the last glow disappeared." 

Capt. DE Bmto Capello sent a report, published in the * Standard ' of December 
26, 1883, as' follows: — 

" Captain Capello, of the Lisbon Observatory, has sent us a succinct account of 
the late crepuscular phenomena of the rising and setting of the sun. In the first 
place, he remarks that they have been seen in feebler degree from October the 15th 

* * Me*. Zeitschrift,' yol. i. (1884), p. 162. 

t * Bibliofch^qae Uaivei-selie, Geneva, Archives dee Sciences Physique etNatui-eUes,' Tome XI II. — 
Pebraary 15, 1885. 



170 THE HON. ROLLO RUSSELL 

to the 23rd or 24th of that month, showing themselves in a region or segment of 
parabolic form in the west-south-west, the vertex inclining towards the north-west.' 
This region was red*orange coloured close to the horizon ; following this was a rose 
tint, more or less faint, and again an elongated region of very delicate pearl-white. 
The white region appeared to be formed of very fine cirrus and cirro-stratus, like 
skeins of white silk ; the cirrus was not noticed before the setting of the sun, 
neither had the solar halo been seen which is always produced with the cirrus xmder 
normal conditions. According as this region moved down towards the horizon, 
the white light lost much in intensity, and disappeared, leaving, as in ordinary 
circiunstances, a red-orange band close to the horizon. The red coloration elevated 
itself sometimes to the height of 30° to the west-south-west, and was seen an hour 
after sunset. The 18th October seems to have been the maximum of these 
phenomena. 

" In the last days of November, and in the early days of December, these 
phenomena were observed in much greater intensity on some days, both at the rising 
and at the setting of the sun. Over and around the region of very vivid pearl-white, 
the colours of the twilight, very bright and exaggerated, the crepuscular and anti- 
crepuscular arcs, which, under normal conditions, are arcs of a circle, have shown them- 
selves in parabolic form. The redness of the sky (red and red-violet) showed itself 
sometimes for two hours after sunset, and spread itself in very grand force to 60° and 
70° of height. The duration of the coloration of the sky is most considerable at 
elevated points. Thus, at the meteorological station of Serra da EstreUa, 1441 
metres in altitude, they have observed the redness of the sky up to nine o'clock at 
night. It should be remarked, also, that during all these days the sun was encircled 
by a region of whitish light, fringed with pale orange-rose colour. This region never 
appeared circular; one could not well define the figure it presented, as it had 
irregular borders, something like the corona of the sun in total eclipses. In the first 
days of December (1st and 3rd) these crepuscular phenomena showed themselves with 
greater intensity, and on the 3rd and 4th there was, at 4.45 p.m. Lisbon mean time, Bome 
minutes after the actual setting, on the side opposite to the sun (east-north-east), a 
segment which elevated itself from the horizon in parabolic form inclined towards the 
north. On the side of the west-south-west, where the sun went down, there was 
seen another much larger segment, affecting also the parabolic form, with the red, 
orange, and pearl-white colours, at first feeble, but augmenting rapidly in intensity. 
After a little while, towards 4.55, the pearl-white region showed itself silvery, and 
with the greatest splendour, the other colours preserving nearly the same relative 
positions, only between the white and the orange a band of very clear green showed 
itself Then, at 4.58, there began to appear rose and clear violet colour encircling 
the white ; and at 5 p.m. the rose elevated itself to the height of 50°. All the 
eastern side of the town was illuminated in a peculiar manner, and this illumination 
lasted for about 12 minutes. This rose tint, more or less violet, went up to the 



ON TEE UNUSUAL TWILIGHT GLOWS. 171 

north, during which, in the south, one saw a broad band of orange-yellow. On the 
east side, the pale yellow at 4.55 p.m. was augmented in intensity, and showed itself 
very high (maximum elevation) ; the other colours presented themselves nearly in the 
same relative positions. After 5 p.m. all these colours of the east-north-east 
decreased rapidly in extent as well as in intensity, and in a little time (5.5 p.m.) 
there remained only a violet arc from north-east to south-east. Towards 5.3 p.m. 
the pearl-white region (west-south-west) sank little by little in the direction where 
the sun had set, losing its brilliancy, whilst above, a new region of yeUowish-pinfc 
rose to 75^, extending from north to south. The sky at the zenith was then of a 
deep azure, almost black, and the moon showed itself of a green colour. A little 
later, 5.8 p.m., the exterior rose region presented itself streaked by different blue 
rays, which diverged from the point where the sun was below the horizon. The 
phenomenon was very like aurora bore^lis. Little by little the colours chauged ; the 
white region became very narrow, and, sinking towards the horizon, It assumed, at 
5.15 p.m., a red-orange, bordered with gold. Soon after, the phenomenon ceased. 
At 5.18 to 5.20 p.m. the red coloration, more or less violet, extended itself rapidly all 
over the horizon from north to south, reaching, on the west, to 60° of elevation ; and 
this red coloration maintained itself up to 6.30 p.m., that is, for an hour and forty 
minutes after the setting of the sun. Since the 3rd instant these phenomena have 
lost much in intensity, bqt all the characteristic points have been preserved — for 
example, the parabolic form of the crepuscular and anti-crepuscular arcs, and the 
white and coloured spaces. On the 12th, the redness of th0 sky was observed up to 
6.20 p.m. During the whole period the magnetic curves have presented nothing 
extraordinary, apart from some little perturbations very common during the maxi« 
mum of solar spots." 

Professor von Helmholtz* wrote from Berlin on December 1 : — " The pheno- 
menon called cloud-glow in your last numbers, was seen also at Berlin on the three 
evenings of November 28, 29, and 30. As far as 1 qould observe the sky, the details 
were almost the same as your correspondents describe them : a greenish sunset at 
3.50 ; an unusually bright red sky with flashes of light starting from south-west. 
An interesting physiological phenomenon, which we call ' Contrast/arben,' was there 
beautifully illustrated by some clouds, no longer reached by direct sunlight ; they 
looked intensely green on the red sky. At 4.30 the streets were lighted by a 
peculiarly pale glare, as if seen through a yellow glass. Then darkness followed 
and the stars became visible. But half an hour afterwards, at 5 o'clock, the western 
fiky was again coloured by a pink or crimson glow. Persons who were not quite 
sure about its direction mistook it for an aurora ; others spoke of a great fire in 
the neighbourhood. . . At 6 o'clock all was over." 

• 'Natui-e,' vol. xxix. (1883), p. 130. 



172 THE HON. EOLLO BUSSELL 

Mr. Gerard Hopkins, of Stonyliurat College,* notes the following difference 
between ordinary sunsets and the displays of 1883 : — 

"(1). They differ in their time and in the place of the sky where they 
appear. 

" (2). They differ in their periodic action or behaviour. 

" (3). They differ in the nature of the glow, which is both intense and 
lustreless. 

" (4). They differ in the regularity of their colouring. Four colours in particular 
have been noticeable, orange lowest and nearest the sundown; above this and 
broader, green ; above this, and broader still, a variable red, ending in being crimson ; 
above this, a faint lUac. The lilac disappears, the green deepens, spreads, and 
encroaches on the orange, and the red deepens, spreads, and encroaches on the green, 
till at last one red, varying downwards fi-om crimson to scarlet or orange, fills the 
west and south. 

*' (5). They differ in the colours themselves, which are impure and not of the 
spectrum. 

" (6). They differ in the texture of the coloured surfaces, which are neither 
distinct clouds of recognised make, nor yet translucent media." 

The above is merely an abstract of Mr. Hopkins's letter, to which he subjoins 
a very lucid description of the sunset of December 16, 1883. 

Herr Dr. E. von Rebeur-Paschwitz v«Tote,t on December the 19th, from 
'Berlin: — "Yesterday, December 18, the twilight phenomenon, though much less 
grand, was very well seen. Soon after sunset, the western sky, which seemed to be 
covered with a very fine vapour stratum, but otherwise was cloudless, assumed a 
greenish-white colour. At about 4.15, at some altitude above the horizon, the 
first reddish sheen was observed ; and it soon expanded over a larger oval space, and 
increased in intensity. This space filled with red light did not reach to the horizon, 
but was separated from it by a narrow streak of white of intense brightness. At 
last the whole horizon in the west shone with a beautiful orange colour. Yesterday, 
as on the 17th, a fine striation of the bright part of the sky was noticed. Broad 
streaks, inclined to the horizon, and nearly parallel, covered the western sky. 
The inclination of the streaks was variable ; on the 19th they were nearly parallel to 
the horizon. This striation of the sky has been seen on three successive evenings, 
and also on the first days of December. Through an opera-glass the streaks looked 
like fine clouds, but could hardly be described as cirrus. At 4.53 the red glow was 
all but gone ; at 5.2 there was another weaker redness, more towards the north than 

* 'Nature/ vol. xxix. (1884), p. 222. 

t * Met. Zeitsohrift,' vol. i. (1884), p. 160. 



ON THE UNUSUAL TWILIGHT GLOWS. 173 

before ; at 5.5 a sudden renewal of the red glow ; at 5.20 there was a diminution ; 
and at 5.30 the glow had disappeared." 

Mr. E. L. Layard* wrote as follows, on January 6, 1884, from Noumea, New 
Caledonia : — '* As soon as the suns disc has disappeared, a glow comes up from the 
west like that of whit^-hot steel, reddening somewhat as it mounts to the zenith, but 
changing the while to blue. From the zenith it passes into the most exquisite green, 
deepening as it loses itself in the east. As the sun sinks lower and lower, the red 
tints overpower the white-hot steel tints, and the blue of the zenith those of the 
green. At 7 p.m., or a little after, nearly the entire western half of the horizon has 
changed to a fiery crimson : as time goes on, the northern and southern areas lose 
their glory, and the greys of night contract, from the northern end first, most rapidly ; 
the east is of the normal grey. The south now closes in, and presently, about 8 p.m., 
there is only a glare in the sky, just over the sun's path, as of a distant conflagration, 
till the fire in the west dies out. I have been attempting to describe one of our 
cloudless evenings, of which we have had only too many, having just come through 
a fearful drought that has lasted all this while ; but who shall paint the glory of 
the heavens when flecked with clouds ? — burnished gold, copper, brass, silver, such as 
Turner in his wildest dreams never saw, and of such fantastic forms I " 

M. de MoNTESSUS, writing, "Sur les lueui-s cr^pusculaires observ^es k San 
Salvador (Am6rique centrale)," t under date February 9, 1884, says : — 

" The remarkable sunsets have been seen here since the last days of November, 
1883. About half an hour after sunset, and an hour before sunrise, the horizon is 
gradually illuminated with a magnificent coppery -red tint, very constant in colour, 
very intense, and lasting on the average 20 to 25 minutes. The phenomenon is not 
produced except in a cloudless sky. If there are a few strati on the horizon in the 
evening it is not produced ; in the morning it may occiu: with a few strati, and 
especially with high cirri. The illumination extends, horizontally, at least 70^ to the 
right and left of a plane passing vertically through the sun and reaches up nearly to 
the zenith ; consequently, nearly half the hemisphere is filled with the splendid red 
glow. The moon, when circumstances allowed of it — that is, when her altitude did 
not exceed 15°, was coloured a magnificent emerald -green, and it was extremely 
beautiful to see it at the epoch of grey light {lumiere cendree), when its disc was of a 
pale green, with its crescent horn deep green in the midst of an immense crimson 
curtain. Venus only was able to penetrate the curtain, and was also green. Stars 
of the first magnitude could not be seen ; and those which at a sufiiciently great 
altitude, such as the small comet, were clearly distinguishable, were also green. 
The phenomenon rapidly acquired its maximum intensity, which it retained 3 or 

* 'Natnre,' vol. xxix. (1884), p. 461. 
t ' Comptes RendnB', xcviii. (1884), pp. 761, 762. 

2 A 



174 THE HON. ROLLO RUSSELL 

4 minutes only, and then as rapidly disappeared, after lasting altogether about 25 
minutes. I did not at first note down the dates of the first appearances. There 
were two or three before November 30. Subsequently they were — November 30, 
December 1, 2 ; January 3, 4, 7, 17, 18, 21, 22, 23, 25, 26, 27, 28, 29, 30, 31 ; 
February 4, 6, 7. Yesterday the overcast sky allowed us to see it only at intervals 
for a few minutes. At Panama some of the old men report having seen similar glows 
before, but they could not recollect the precise year. The magnetic needle was 
quiet. There was nothing unusual recorded by the meteorological instruments. The 
centre of the glow seemed to be in the vertical plane of the sun. The zodiacal 
light was absolutely annihilated." 

Mr. John Ballot, of Roefontein Wakkerstroom, Transvaal, S. Africa, in a letter 
dated March 10, 1884,* says: — "The exact date on which the glow made its first 
appearance in this country, I am not in a position to give. It is, however, certain 
that it was observed as early as September 5, 1883. From about September 7, it 
had already become a very noted peculiarity after sunset, even to the most imob- 
servant. The colour of the light was at first of a sickly greenish-yellow, but deepened 
into a copperish-red as the evening advanced ; the light was strong enough to cast a 
deep shadow against a wall or anything else, if an object was held close to it. • . . 
The greenish tint of this glow seemed to me to prove that it was caused by light 
reflected and refracted by an atmospliere heavily charged with water vapour." 

Therefore Mr. Ballot predicted heavy rains and the disappearance of the 
glows. The rains came, but the glows, nevertheless, continued to March 10, the 
date of writing. 

" The glow remained visible almost every evening whenever there was suflEicient 
clear sky to reveal it. . . . One evening it would attain to a greater altitude 
than another, or be more brilliant. As time went on, the general colour of the light 
seemed to deepen to a darker copperish-red or muddy-orange, with a shade of rosiness 
diffused in its remoter parts. . . . The general tint is cei-tainly much deeper 
than it was at first. The conditions most favourable to a grand display and cloud 
effect are a clear sky towards the time of sunset, with a few detached clouds floating 
about, and a slightly cloud-streaked horizon. When such has been the case I have 
frequently observed innumerable rays of the beautiful glow darting out from behind 
the cloudy horizon to great altitudes, and in every direction, the intervals between the 
rays being comparatively dark. , . . That the reflecting medium producing the 
glow is situated at greater altitudes than the general cloud layer is proved by the fact 
that these cloud masses appear quite black when projected against the rosy back- 
ground. The thinner edges of such clouds frequently acquire a dark olive-green 
colour ; while at other times I have seen them slightly rose-coloured by the reflection 

* ' English Mechanic/ May 2, 1884, p. 185. 



ON THE UNUSUAL TWILIGHT GLOWS. 175 

of the glow, the cloud itself remaming a dark mass. . . A few concluding remarks 
will be devoted to the order in which the glow is generally formed. A rough diagram 
is annexed, simply to enable the reader better to understand the description. 

Fig. 14. 




"h h, the horizon; A A^ fading portion of ordinary twilight, with the point of sunset heavily shaded; B B, the 
brownish belt of glow due to denser lower strata; C C, vacant spa^ce between, the two glows^ above 
which the second glow begins to form; D, the bluish-white glare; E E, the copperish-red gloxo; 
K, where the purplish tint is brightest, fading into violet at j. 

" Soon after sunset, the usual twilight appears, which remains visible for a short 
while ; as it gradually contracts and fades, everything seems to be settling down for 
the approaching darkness. The rosy glow over the point of sunset rapidly contracts, 
only a thin rim of red remains visible on each side, with a small arc of red marking 
the point of sunset. The observer will now begin to notice a peculiar bluish-white 
glare forming a few degrees above the arc of red, and extending some distance 
upwards. The white glare increases a little, when again a slight reddish tint makes 
an appearance round about the white. When once commenced, the red light spreads 
rapidly upwards and in a horizontal direction, but does not seem to make much 
progress towards the horizon. The fading rim of the first twilight forms itself into a 
long, narrow, brownish belt, stretching along the horizon, caused, no doubt, by the 
denser layers of haze and vapour lower down. Immediately above this belt, and just 
below the bluish-white glare, there remains an apparent blank ; this blank is but 
slowly filled up by the new glow. It seems as if the reflecting media in that belt are 
below the line of reflection as yet. As the glow spreads outwards above the white 
glare, it seems to acquire a strong tinge of purple, which gradually fades into a violet 
near the borders of the spreading luminosity. The arc of bluish-white gradually 
gives place to a very strong copperish glare. But as the evening advances the light 
assumes a more uniform colour. The purple and violet entirely disappear, and the 
enttt^ luminosity contracts towards the point of sunset, where it finally disappears at 
from one to one-and-a-half hours after sunset. . . . The glow generally has a much 
greater extension round the southern horizon than round the north-western. It 
fi-equently extends more than 90° round the southern, whereas it seldom exceeds 60° 
round the northern. Taking everything into consideration, there seems to me 

2 A 2 



176 THE HON. ROLTiO RUSSELL 

decided proof, from these observations, that aqueous vapour plays an important 
part in producing the after-glow." 

Again, he says* that during March and April peculiarities were strongly devdoped 
which had not been noticed before: — " All throughout March I frequently observed it 
in broad daylight, especially one or two hours before sunset* But as the sky was 
generally covered with broken cloud I thought it peculiarly favourable to reveal the 
illuminated dust haze beyond, the sun himself being covered from view at times. 
April, however, brought a clearer sky, yet the glow forms an easily-detected daylight 
phenomenon. About 3 minutes after sunrise it is plainly seen on each side and along 
the horizon, even above the sun. The sides and lower portion of glow ai^e of a 
brownish-grey, while above, or preceding the sun, it is wbitish-grey. The sun with 
the surrounding glow resembles in shape a huge comet, of which our luminary forms 
the gigantic nucleus, the head and part of the tail alone having risen above the 
horizon. This glow gradually contracts about the sun, being always much elongated 
on the side nearest the horizon. About midday a faint white glare alone is visible ; 
but towards afternoon the same phenomenon as at sunrise occurs, only reversed iu 
direction. Some moments after sunset the bluish -white heart-shaped glare forms 
itself; on each side, a dull brownish-red arm of light is seen stretching northward and 
southward along the horizon. Some minutes later, and just about when the heart- 
shaped bluish-white glare attains its brightest, an arc of light is formed in the eastern 
sky, resting on the band of light or band of glow which now surrounds the horizon. 
This arc resembles in shape a small segment of a rainbow, and rises to an altitude of 
about 50° to 60°. Inside there seems to be a blank or want of light. Meanwhile 
the secondary glow is beginning to form in the west at an altitude of about 40°, and 
just over and round about the bluish- white glare. A few minutes later and the whole 
sky seems to show a feeble illumination, while the arc of light in the east rapidly disap- 
pears. The secondary glow has now reached a deep rosy-red tint, as before described ; 
at first seemingly floating some degrees above the horizon, but gradually sinking lower 
and acquiring more uniformity of textura The regions near the horizon pass through 
bright yellow to dark orange very deep in tint. About 45 minutes after sunset this 
secondary, and most magnificent glow, contracts towards the point of sunset and 
settles on the horizon line. As soon as this happens, the arms of light and general 
luminosity of the sky mentioned above entirely disappear. Stars of smaller magni- 
tude become better defined, and the twinkling of the stars in general seems to 
become more decided. Everything settles in for night and darkness. When, lo 1 
the seemingly expiring glow in the west is again seen to increase ; about 45° above the 
horizon a similar duU glow is forming, which increases in Uke manner as the secondary 
glow. The pale glow over thehprizon assumes a peculiar greenish-yellow, which 
gradually deepens into a muddy fiery red. A third glow appears, and behaves much 

* ' English Mechanic,* Jane 6, 1884, p. 296. 



ON THE UNUSUAL TWILIGHT GLOWS. 177 

the same as the secondary glow, only its general tints seem duller. This glow has 
but little reflecting influence on the now rapidly-darkening sky, situated further 
eastward, which produces a strange effect of contrast. It seems to me that this 
glow may be caused by reflection from dust haze situated at a greater altitude 
thaji the dust haze of the secondary glow. In other words, there are two layers 
of dust floating in the upper strata of the atmosphere, but at very different 
altitudes ; while in between them there can be but little diffused dust floating 
about, hence the interval between the glows." 

M. Pelagaud writes, on AprU 14, 1884, from St. Paul, Bourbon, as follows : — 
" NouveUes observations d'illuminations cr^pusculaires kl'ile Bourbon.* Our twilight 
glows have passed into a new phase, the intermittent phase. Some days they almost 
entirely disappear and are represented only by a slight phosphorescence ; then the 
next day they recur with renewed intensity. 

" On April 4, they were admirable and as beautiful as ever ; and again on 
AprU 1 1 ; but they did not have the same arrangement as at first. Then they 
consisted of three large tricoloured zones, which extended from the west to the 
zenith, and were sometimes separated from one another by three wide coloured 
bands of blue sky. Now they are usually glories which shoot up in divergent 
rays to 50® or 60° At 7 or 8 minutes after sunset a pale luminous lilac spot 
begins to be defined at 10° or 12° above the point where the sun has disappeared ; 
its diameter may be about 15°. To the right and left are two smoky walls like the 
smoke from a large town, seen as a transparency against the red horizon of the 
setting Sim. Then these walls vanish, the lUac spot disappears ; and just above it 
there begins to appear, about 15 minutes after sunset, a luminous haze of scarlet 
pintle and crimson hue, and of a discoidal form, which gradually widens to 15° or 
20°, increasing in intensity of lustre, and, soon after, shoots upwards the great 
rays above-mentioned. At the moment when these rays appear the lower margins 
of the disc retract, and take the form of an arc of a circle resting on the horizon ; but 
all the margins are indefinite. Sometimes obscure rays are observed between the 
bright ones, especially on the south side. * All this lasts a quai-ter of an hour or 
20 minutes, and then gradually fades away untU, at about 6.35 or 6.40, there remains 
only a yellow band on the horizon, which also soon disappears. I am induced to 
think that the phenomenon is electrical. Cyclones have been unusually prevalent, and 
these exclude all hypotheses as to the suspension of fine particles in the higher 
atmosphere for upwards of six months. On the other hand, I have seen (once only, 
it is true) a roseate haze start from a very high cirro-stratus." 

Prof, von BKZOLD,t of Munich, observes that : — " Besides the extreme brilliancy 
and depth of colour some other points may be specified as abnormal : — 

• * CompteslRendTis,' xcviii., pp. 1301, 1302. 
t * ZeiiBcHrift fur Meteorologie,' 1884, p. 72. 



178 THE HON. ROLLO RUSSELL 

1. " While, in ordinary conditions, after sunset or before sunrise, an increase 
of brightness is observed in the neighbourhood of the sun (near the horizon), 
having the form of a weakly illuminated disc with a spot above the sun for 
its centre, this appearance has lately been far more striking than usual. 

2. "Immediately before sunrise, or after sunset, the illumination of the sky, 
particularly with a hazy atmosphere, turned to a peculiar yellow, often of a sulphur 
colour, such as is not seen in ordinary twilights. 

3. "The illumination of the whole sky was unusually diffuse, so that the 
boundary of the so-called earth shadow could never be clearly recognised. 

4. "The first purple light, of which the maximum appeared from 30 to 35 
minutes after sunset between Januaiy 8th and 1 3th, was much more extensive 
and less well defined than usual. Whereas usually it appears as a defined disc 
above the bright yellow segment, so that its lower part appears to be covered 
by the yellow, and whereas it very seldom reaches to the zenith and never beyond 
it, in the recent twilights the greater part of the sky was frequently flooded 
with purple light. 

5. " Quite abnormal, too, was the extent and intensity of the second purple 
light. It reached its maximum about 70 or 80 minutes after sunset, as in a 
normal twilight, but was incomparably brighter, and much more strongly coloured," 

F. A. RoLLO Russell 



PART IV., SECTION I. (b). 

Proximate Physical Cause of the Unusual Twilight Glows 

IN 1883-4, 

By the Hon. Rollo Russell. 

The condition of atmosphere most favourable to the visibility of the complete 
and undisturbed fore-glows and after-glows of 1883-4 was freedom from clouds, and a 
transparent lower air. Any haze of an ordinary kind in the upper or lower air 
greatly interfered with the characteristic phenomena. Also when the unusual 
haze which accompanied, and, as we shall show, probably produced, these phenomena, 
was present in sufficient quantity to cause an appearance of mist on the horizon and 
to obscure the sun before setting it was unfavourable to the observation of fine displays. 

This latter condition prevailed in Surrey on November 23, 24, and 25, 1883, 
the sun vanishing in a misty film of striae resembling indistinct cirro-stratus. 
The sunset on those days was followed by appearances detailed in Section I. (a), 



ON THE CAUSE OP THE UNUSUAL TWILIGHT GLOWS. 179 

pp. 152-178. The sun as it sank into the haze was peculiarly white, but not well- 
defined, being surrounded by a kind of halo and having a green light above it. This 
haze seems to have been very similar to that which, three months earlier, obscured 
the sim in the tropics near the equator ; while, further from the equator, where the 
lofty haze was less dense, brilliant after-glows were seen. Several observers 
in the Atlantic, Indian, and Pacific Oceans, described the sun as disappearing at 
some altitude above the horizon. 

The white haze described in Section I. (a), when distinctly visible as a stratum 
at a great altitude, was favourable to the production of fine displays, and preceded 
the most brilliant and extensive after-glows. At Honolulu the sky was seen to be 
covered with a very light wavy mist, and in many parts of the world a lofty striated 
haze was seen previous to the red illuminations of the sky. In England it was 
noticed by several observers. In Italy, in January, 1884, the white gauzy veil after 
sunset was the surest prelude to a display. In Europe, as stated in Section I. (a), 
the stratum in fuU daylight was white, apparently nearly motionless, and almost 
invariably arranged in parallel streaks stretching from about south or south-west to 
north or north-east. It gave the impression of lying at a very great altitude ; and 
this impression was strengthened when it was found that, for more than two months, 
through all kinds of weather, it persistently preserved its peculiar character and 
apparent immobility, even when high cirrus clouds were moving rapidly ; that after 
sunset and long aft;er the highest clouds in the neighbourhood had lost their colour, it 
seemed to be illuminated by direct sunlight ; that it was accompanied by the appear- 
ance of a corona round the sun during the day, much better visible at altitudes of 
10,000 feet than lower down ;* that the streaks of which it was composed converged 
to a radiant point much below the horizon, and gave the impression of being really 
parallel, and that though the duration of the morning and evening glows gradually 
diminished, the stratum did not, for some months, reach a level affected by the 
currents of the cirrus region. 

We may thus fairly conclude that a stratum of matter, not usually discover- 
able, was present in the upper atmosphere of a great part of the globe during the 
autumn and winter of 1883-4, that is, during the period when the remarkable 
glows were conspicuous. The first remarkable sky colorations of long duration 
were observed at several places in the Indian Ocean on August 26 and 27, and 
rapidly extended in various directions, but chiefly W. and S.W. Lines drawn from 
place to place in the order of dates, if prolonged backwards, meet somewhere near 
the Strait of Sunda, which must therefore be taken to be the place of origin of the 
cause of the glows. On the same days the ocean was covered to a long distance, 
especially westward, with a very fine dust, consisting chiefly of pimaice, floating lightly 
on the surface ; and this fine dust was noticed to fall from the sky as far as 1,175 

♦ FoRBL, in Switzerland (* Comptes ' Rendua,' xcix., p. 423) ; and Hetde, at Kailong, Lahoul, 
India (MS.) ; and Backhouse (* Nature,' Au^st 14, 1884). 



180 THE HON. ROLLO RXTSSELL 

English miles west of Java on A^ugust 28, and at 3,754 English miles W.N.W. on 
September 8. This also, by the order of dates, showed an origin near the Strait of 
Sunda. A whitish or yellowish sky and a blue or green sim were seen on the same 
days, August 26 and 27, and first in the neighbourhood of the Strait of Sunda ; 
so that all these phenomena depended on some agency at work in that quarter. 
The widely-extended-fall of dust from this yellowish sky, and the long-continuance 
of the haze in the upper regions, make it reasonable to assume that the lofty stratum 
consisted of exceedingly fine dust, projected by some cause to a height above that of 
the known atmospheric currents. 

The great eruption of Krakatoa on August 26 and 27 appears to be an adequate 
cause. And its potency can hardly be doubted when w^e compare ite effects with 
those of two other years of great volcanic activity, namely, 1783 and 1831, which 
were distinguished by similar coloured suns and red after-glows.* The redness of the 
sun in 1783, which was more frequent than the moon-like appearance, may be 
attributed to the density of the volcanic haze in the lower and intermediate air ; and 
this condition had its counterpart in 1883 in the Indian Ocean, wherever the lower 
as well as the upper air was unusually hazy. The haze which caused the blue sun 
in the tropics did not lose its properties as it spread northwards ; for in Europe the 
sun appeared whiter than usual at low altitudes, the moon was occasionally 
slightly greenish during the night, and the stars were less yellow and more 
green. As in the tropics, the red after-glows accompanied the red-arresting or 
blue-sun haze, when not too dense. If the influence of the lower atmosphere 
could have been eliminated, there can be little doubt that a greenish tinge would 
have slightly predominated in the sun half an hour before sunset. In China, for 
example, the sun was seen green in November, and the fiery sunsets took place 
soon after. 

In order to realize the effects of absorption (so-called) at heights beyond the 
paramount influence of the lower air, let us place ourselves in imagination in the 
middle of the lofty dust-stratum, and observe the appearance of the sun as it 
approaches the horizon. When it reaches a point at which it is shining through a 
maximum length of the stratum, it must appear greenish or bluish ;t then, as it sinks 
lower, the proportion of intermediate lower air increases, and the solar disc may 
appear white,+ an equivalent portion of the violet end of the spectrum being now 
arrested. Still lower it wiU appear yellow, orange, and red in succession, as the lower 
and more vaporous strata relatively increase in effective power, these colours being 
far more brilliant than we are accustomed to see at low levels, owing to the smaller 

* See Section Y., pp. 388 and 396. 

t For the atratnm is sapposed to consist of particles similar to those which caused the bine sun in 
the tropics. The real colour of the sun at great altitudes is here assumed to be white, though, according 
to Prof. Lakolst, it approaches violet. 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 181 

proportion of gross vapour, dust, and impurities, and the greater length of inter- 
vening air. The red colour of the sun, when seen at sunset on a clear day from 
a mountain top, is brighter and purer than when seen through a dense mist at 
midday to leeward of a large town which bums smoky coal. The red tints 
reflected from the loftiest Alpine summits and high clouds at sunset show more 
brilliancy than those reflected from lower clouds, partly, no doubt, owing to the 
contrast of the increased darkness and the absence of other colours in the interme- 
diate air. 

Now, instead of occupying in imagination the position in the middle of the dust- 
stratum where these changes in the sun's colour would become apparent, let the 
observer watch the stratum from the surface of the earth from a few minutes after 
sunset. If the stratum be supposed to contain a multitude of small coloiu'less 
particles, and to be only moderately dense, the colour-changes before observed in the 
fiolar disc will be seen by reflection in the vault of the sky, and will only be masked 
by the blue effect of the ordinary sky particles where the white surfaces are seen 
least obliquely, as overhead. The maximum effects of colour wiU occur where the 
influence of perspective, unimpaired by atmospheric opacity, is greatest, and the 
light strongest in comparison with that of the intermediate air. The whole sky 
will be illmninated by diffuse reflection of the sun's rays, if the reflecting particles 
be opaque, and the order of colours will be uniformly greenish-blue, green, white, 
yellow, and red in succession, each colour appearing first in the east, and passing 
over to the west. Even if the surfiices were tinted, somewhat similar colours 
would be observed, as may be seen when a bright yellow or red sun, in setting, 
tinges all objects with the same hue. This effect is especially noticeable when the 
air is clear after a heavy shower, and when diffuse light from the sky is intercepted 
by clouds. 

But, do these contingent phenomena correspond with what actually took place 
over England in the glows of December, 1883 ? On some few occasions the 
resemblance was close, but usually the strong coloured illumination was confined to a 
part of the sky between the horizon, near where the sun set, and the zenith ; and 
frequently the sky towards north and south remained of the usual blue colour. From 
December to the beginning of February the arc of colour contracted in area, and 
occasionally the luminous cloud shaded off rapidly into deep blue at the edges. 
The luminosity of November 9 was sharply defined, but on that occasion the matter 
concerned seemed not to be spread over the sky, but separated into distinct cloud- 
like masses. At the end of November and beginning of December, the whole sky 
was illuminated with yellow and red, in the manner that might be expected on the 
foregoing assumption. The blue and green did not, however, appear clearly in the 
east before reaching the west, probably owing partly to the amount of bright and 
mixed colour in the still strongly illuminated intermediate air soon after sunset, lliis 

general redness, seen in the first fortnight of the remarkable series of after-glows in 

2 B 



182 THE HON. ROLLO RUSSELL 

England, always occurred when, in a favourable light the white layer of matter was 
noticed to be particularly dense, and never occurred when the layer was previously 
almost invisible; though brilliant glows might then be seen between the western 
horizon and the zenith. 

The hypothesis, then, by which the glows were assumed to have been wholly 
due to the action of small ojyarjue particles of mineral dust distributed in a stratum 
of still smaller particles, fails to account for the moderate extent and peculiar 
character of the coloured arc on most occasions. It fails to account for the 
opaline whiteness of the sheen soon after sunset, for the great brilliancy of the 
orange and red colouring in the late twilight, and for the metallic cast of the 
colours. 

But let it be assumed that instead of ordinary opaque particles of matter, most 
of the larger particles in the stratum consisted of glass-like laminae or very thin 
fragments and spherules, and the peculiar characteristics of the after-glows admit of 
fuller explanation. The small dust of the glassy particles must be imagined to lie 
in all kinds of positions and at all angles, according to their form and centre 
of gravity. The majority would presumably be horizontally disposed, or, if curved, 
would have their convex side downwards. Whether lying horizontally or hanging 
vertically, the situation directly above the observer would clearly be unfavourable 
for reflection vertically downwards. Some time after sunset, the maximum bright- 
ness would take place between the observer and a point vertically above the sun, 
by regular reflection from smooth horizontal surfaces, and the part of the sky 
next in brightness to the western arc would be the east, where the effective 
reflection would be from nearly vertical surfaces and from spherules, for water 
particles in clouds near the eastern horizon are strongly luminous at sunset, and 
vitreous particles would reflect in a similar manner. The sky in the north and 
south would be little affected by direct reflection from such particles, and 
might sometimes appear greenish-blue by repeated reflection and scattering of 
light from beyond through the red-arresting stratum, but close to the horizon a 
certain amount of redness, less than ordinary, might appear, owing to scattering 
and sifting out of blue rays by the lower strata and to secondary reflection by 
ordinary dust. A greater density and preponderance of spherules and fragments, 
would cause the whole sky to be bathed in red or orange, as it is occasionally with 
extensive cirro-stratus. For, when a thin high ordinary cloud spread over the sky 
except in the direction of the setting sun, is illuminated after sunset, the 
spherules of which the cloud is composed will reflect the sun's rays in every 
plane, so that a red colour is observable in all directions. 

The failure of the red glow to appear overhead, except when the stratmn 
was at its densest, would be due (l) to the less favourable angle for reflection, 
(2) the less depth of matter in the line of sight, and (3) the greater intensity of the 
blueness of the sky which would neutralise the red. A Nicol prism revealed to 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 183 

Mr. AiTKEN* the red light overhead before it appeared in the west after sunset, 
even when quite invisible to the naked eye. 

Now, let us examine the grounds on which the assumption that the lofty stratum 
actually consisted of glaasy laminae may be based, 

We have, above, stated the reasons which favour the theory that the stratum had 
its origin in the projection of a mass of fipe dust from the volcano in eruption in the Strait 
of Sunda, \fhen the remarkable long-ejiduring sky-illuminations were first observed. 
All reports agree in stating that the fine dust collected at great distances from the 
volcano consisted chiefly of fragments of pumice blown into very thin transparent 
plates ; and Mr. STANLEvt found that the dust which fell on tha Arabella at 1,127 
English miles west of Java Head, on August 28, contained small irregular plates of 
pumice, a vast number of which seemed to be broken shells of pumice bubbles, of 
thicknesses varying fron^ '001 to '002 mm. Many of these small pieces wpre nearly 
square and curved, but there are types of all forms incidejit to fracture. A large 
number of thin plates are thicker on one edge than on the others, having the form pf 
wedges. Thje volcanoes of Java produce these thin glassy plates of pumice through 
enormous steam pressure in the interior and the sudden expansion of the masses 
blown out into the atmosphere. J Professor Bonney found the *' glass foam " of 
Krakatoa to be more expanded by internal steam pressure than the glassy dust of 
the Andes. The fragments of bubbles woul(j, therefore, be thinner and finer than those 
which fell 65 mjiles away after an eruptign of Cotopaxi, pf wl^ich Mr. Whymp^r found 
that fi:'om 4,000 to 25,000 were required to weigh a grain. Those T^hich did not 
fall so soon would of course be far thinner and smaller. Messrs. Muri^ay and 
Renard § have found by a microscopical examination of Krakatoa pumice that its 
fracture has probably been o\^ng to a tex^sion like that observed in Rupert's drops. 
The particles have ragged edges which show disruption of a vacuolated or bubble-like 
structure, A rapid cooling and decrepitation must take place in the passage of the 
heated pumice masses through the air ; and thus a vast quantity of extremely finely- 
divided matter be carried ii^to the higher atmosphere. 

Crystals in granitic rocks and some lavas contain great numbers of excessively 
minute cavities, often filled with liquids. It has been estimated that in some 
instances the number of these minute liquid caviti^ amounts to from one thousand 
miUions to ten thousand millions in a cubic inch.|| 

Dr. Flogel's researches IT on the dust which fell on May 21, 1883, on board the 
Elisaheth, near Sumatra, also showed that by far the greater part of the asji is a 

* * Proc. Roy. Soc. of Edinburgh,' Jnne 2, 1884, 
t * Quar. Jour. Roy. Met. Soc.,' vol. x., p. 187. 
X Bonnet, *Proc. Roy. Soc.,' 1884, p, 124. 
§ *Proc. Roy. Soc. Ed.,' Feb. 4, 1884. 
II JuDD, * Volcanoes,' pp. 61-62. 
t *Met. Zeitschrift,' vol. i. (1884), p. 81. 
2 B 2 



184 THE HON. ROLLO RUSSELL 

colourless glass, which seems to be broken into all imaginable forms. All these glass 
fi^gments contain either innumerable air bubbles or they are full of needle-Uke small 
crystals, or they combine these two. 

The thickest fragments of burst bubbles and the heavier particles fell at or 
within such distances as the Arabella was from Krakatoa ; but the lighter and 
smaller particles were carried much further, and would remain longer in the air in 
proportion to their minuteness. Besides this, the proportion of glassy matter, which 
was the lightest of the ejected products, was found to increase continuously with the 
distance from Krakatoa. 

As the pumice ejected by the Java volcanoes 'consists of an aggr^ation of vast 
numbers of minute glassy vesicles, an unknown proportion of these vesicles would burst 
on suddenly reaching a much lower pressure at a great height in the atmosphere ; 
many, however, might still preserve their vesicular form, owing both to the tenacity 
of their substance and to the condensation of the steam within by great exterior cold. 
The sudden cooling of the exterior crust of a large pumice stone prevents the 
disturbance of the honeycomb atructi^re within, and similarly the cooling of the 
surface of a very small particle may prevent the diminution of pressure from affecting 
the minutest bubbles in the interior. We may therefore suppose that the small 
amount of vapour or gas which had existed within at a very high temperature and 
pressure was, by cooling, condensed to a very small bulk. Some of these small 
particles would accordingly float in the upper air aa microscopic, nearly vacuous, 
perfect balloons. 

The extreme tenuity of volcanic dust has been proved on this as well as on 
other occasions. No watches, boxes, or iQstruments were tjght enough to exclude it 
from their interior.* Thus we may conclude that both in the form of vesicles and 
of fragments of vesicles, an immense volyme of glassy pumice dust of microscopic and 
ultra-microscopic minuteness was pi ejected into the atmopphere on August 26 and 27. f 

Now, what would be the order of phenomena seen from the surface of the earth, 
assuming the existence of a stratum thus composed at a height of from 80,000 to 
120,000 feet above the surface of the earth ? The general tendency of the matter 
being to deprive the sun's rays of a portion of their red, as shown by observations at 
Batavia, Ceylon, Labuan, Cape Coast Castle, etc., the colour of the sun some tima 
before setting, when shining through a great length of it, would a{^)ear green or blue, 
or else less yellow and red than usual, according to the density of the matter. When 
the stratum was less dense, as it was after the lapse of several months, the sun would 
only be rather less red than usual at and before sunset. After sunset, the excess of 

• See the ElisahetJCs experience (Veebbek's * Krakatau,' p. 89). See also Whtmper's ezperienoe on 
Chimborazo during the eruption of Cotopaxi. Bonnet, * Proc. Roy, Soc./ 1884. 

t Mr. Goodwin, of Kingston, Canada, found the most characteristic objects in residue from snow 
on January 13, 1884, to be minute transparent grannies scattered in thousands over the field of the 
microscope. 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 185 

green rays produced by the passage of the solar light through the stratum would first 
be reflected from the suitably disposed particles east of the observer ; but these would 
be partially neutralised by transmission through the lower air, and by the ordinary 
reflection of reddish rays from dust-particles in the middle air, where the sun would 
be much earlier setting than in the stratum. Then the sky overhead would turn 
somewhat green, but the strong blue colour of the still illuminated upper air below 
the stratum would mask it. In the west, the green would in a few minutes 
become visible, yeUow would follow, and orange or pink next, owing to the greater 
persistence of the rays of larger wave length ; but as long as the whole air below 
the stratum was strongly illuminated by the ordinary twLKght, the effects would 
not be very conspicuous. The first colours would be bright only in the west, where 
horizontally floating pumice particles would reflect the sunlight more directly towards 
the observer. Then a reddish glow would appear in the east, caused by the reflection 
of sunlight from those of the particles which were nearly vertical, from small irregular 
fragments, and from spherules. As the sun sank, this redness would pass across the 
zenith, where it would be often masked by the strong blue sky colour, and would then 
become conspicuoifQ towards the western horizon, reflecting the last rays of the sun 
setting at its level. The red arc would sink slowly on the horizon, becoming 
deeper red owing to the gifting out of the more refrangible rays by the lower air ; 
but, when still «|,t some height above the horizon, the green portion, now below 
the horizon to an observer on the earth's surface, but which would not yet have 
sunk out of sight from a point of view at the level of the stratum, would be sending 
its rays eastwards, and wo^ld affect the dust particles at that height with a tinge 
of green, or with a mixture of rays producing a dingy colour compounded with the 
blue of the sky, The next colour to appear in the east opposite the place of sunset 
would be yellow, by reflection from the reflecting arc in the west, but this, again, 
would tend to becon^e reddish as seen from the earth, owing to the great length of air 
through yp^hich it had passed. When, after crossing the zenith, the yellow appeared 
in the west, it would be tolerably bright, but would be modified by the fact that the 
under sur&x^e of the stratum would be receiving different shades of colour from the 
differently coloured bands of the first arc overlapping one another, and the tendency 
would be towards orange, both from the rapidly growing redness of the first arc as 
the yeUow band sank out of sight from the point of view of the high level, and from 
its own descent, and consequ^nt interference of the lower strata. The next colour in 
the east would be red from reflection of the last red band of the finst arc ; and this, 
too, would soon appear with greater brilliancy in tbe west, and would deepen in tint 
as it followed nearly the course of the first arc. With a deep red on the western 
horizon, the second after-glow would end. The fainter and less defined character 
of the second glow would be' owing to its being a reflection from the first arc of 
glowing haze, and not of direct sunlight. 

Such might naturally be taken as the succession of phenomena which would 



186 THE HON. ROLLO RUSSELL 

occur by transmission through and reflection from a stratum composed of small 
reflecting dust, partially transparent and partially opaque, or else consisting of 
a mixture of transparent spherules and fragments, having the qualities described ; 
and such, on the whole, was their normal course, though there were differences 
from day to day, depending on the density and other qualities of the film, and 
on the distribution of clouds and vapour. The yellow was, perhaps, less conspicuous 
than might have been expected ; but we must remember that the red would of 
necessity be the strongest colour near the horizon in ordinary conditions of the 
air, for, a white light near the horizon becomes reddish by transmission, and that 
the sun, when shining most on the imder surfaces — that is, just before sunset 
at the high level — would be rod. Before sunrise the yellow frequently covered 
a large part of the sky, and lasted many minutes, succeeding the red in the primary 
and secondary glows. The succession of colours, which took placQ slowly at the 
high l^vel, appeared in a corresponding manner on the lower clouds in November 
and December. Small detached cumuli overhead turned green, while the sky 
above them was first blue, then pink or orange, showing that the green light in 
the we^t still shone on their lower surfaces, forming, as it were, their secondary glow, 
while the sky above was reflecting direct sunlight. Sometimes they remained pink 
for an hour or more, reflecting the light of the reflected red on the horizon, and 
uns^ffected by the colours too high above the horizon to shine on the under surfaces. 
This persistent tint is evidence of the mere preponderance of certain transmitted 
parts of the spectrum in producing bright colorations, and of the power of the lower 
stratum of air to change the preponderating transmission from green to red, The 
anjount of colour, when there was little redness left on the horizon, even probably 
at the level of these cumuli, showed the effect of a small quantity of light p^ clouds 
in a dark sky. If the stratum of dust had been of a density comparable to that 
of light cumulus, and more transparent, the illumination of the secondary glow would 
have been much stronger than it was. 

The striking predominance of red in the fore-glows and after-glows was owing, 
first, to its greater contrast with the blue sky ; secondly, to the greater surrQunding 
darkness when it appeared ; thirdly, to the lower position of the sun favouring 
reflection from the lower surfaces of the stratum to the earth ; and, fourthly, to the 
red being the last colour, and therefore less mixed with others. To these may be 
added the better penetrating power of red through the lower strata of the atmosphere. 

In several descriptions of the after rglows the red coloration is described as 
appearing in the west and then extending upwards towards the zenith ; and this was 
frequently observed in England. In the magnificent after-glow of November 9, in 
Surrey, the colour grew upwards both in the primary and in the secondary illumina- 
tion. As a matter of fact, the red light must have been passing from east to west, 
but the position of the part of the stratum situated over the western horizon would, 
owing to perspective and the more favourable angle for regular reflection from 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 1S7 

most of the particles at a small altitude above the horizon, cause the faint beginning 
of the glow from the lower surface to appear to the observer before a stronger reflec- 
tion would manifest itself at all nearer the zenith. Frequently a certain amount of 
redness appeared between 10° and 40° above the horizon some minut.es before the 
whole western sky was illuminated ; but on other occasions the red reflection moved 
steadily from the zenith to the horizon, and before sunrise on the days of maximum 
colour it rose from near the horizon to the zenith and passed westwards, leaving 
the east of a light straw colour or green. 

On some occasions the southern, and on others the northern > part of the sky was 
more strongly illuminated than the rest In many of the observations in the southern 
hemisphere this peculiarity was noted, which would merely seem to indicate a greater 
density of reflecting matter in one direction or anothen When, after some months, 
only the finer particles remained, the arc of colour was seen more regularly extended 
over the place of sunset, while the sky, towards north and south, remained blue. 

The capability of vitreous surfaces to reflect powerfully the light of the setting 
sun is experimentally verified by the reflection from distant window-panes eastward 
of an observer, as they glow with an intense brilliancy hardly distinguishable from 
that of the sun itselfw The character of the appearance quite coincides with that of 
the after-glows, though these were, of course, softer and less dazzling. The Crystal 
Palace, viewed at a distance of 8 or 10 miles at sunset, resembles a great fire, and 
small windows, at shorter distances, flame out with surprising intensity. The helio- 
graph is an example of the use to which vitreous and metallic reflection has been put 
in conununicating through great distances. When it is remembered that the after- 
glows took place when the intervening air was no longer in sunshine, but in deep 
shadow, their brilliancy is by no means disproportionate* Panes of glass suspended 
in mid-air westwards would certainly display a similar luminosity from their under 
surfaces. In like manner a rippling sea or lake reflects dazzlingly the rays of the 
setting sun, the waves presenting to them a great variety of inclinations. That a thin 
and previously almost invisible film of transparent particles can reflect conspicuously 
the red light of the setting sun is frequently proved by light cirrus streaks floating 
at altitudes between 30,000 and 40,000 feet. The much greater brilliancy of the 
coloration in the west than in the east in the after-glows would be due partly to 
the position of the fragments, for, the great majority would be floating horizontally, 
but the same eflfect takes place with the spherules of water in light clouds. 

Taking the refractive index of pumice as about the same as that of glass, viz., 
1 "50, the small laminae would show, more or less strongly, the colours of thin plates, 
if tolerably equal in thickness, at thicknesses less than about 70^00 of an inch ; but, 
beyond about 3W000 ^^ ^^ inch, would not reflect much light falling upon them, and 
beyond 200000 ^f ^^ ^^^^ would practically reflect none at all. 

Probably the particles varied greatly in thickness, and would in white light 
reflect a variety of colours, so that the general effect would be colourless or white. If 



IflS THE HON. ROLLO RUSSELL 

an effect of coloration had been due to interference, a part of the sky high above the 
horizon would not quickly have changed in regular order from red to yellow and 
green, as it did, before sunrise and conversely after sunset. The colours of thin plates 
may, however, have had something to do with the opalescent effects occasionally 
noticed above the setting sun and after sunset, and the persistent faint pink and 
green tints sometimes succeeding the brighter colours before sunrise. 

On the theory of mere reflection of the sun's colour by vitreous surfaces as the 
cause of the twilight phenomena, we must still assume the particles to have been not 
less than about soq^qoo of an inch in thickness, in order to reflect much light, coloured 
or white, and since particles which fell on the Arabella at about 1,140 English miles 
west of ELrakatoa were between ^aooo ^^d 35^^)0 of an inch in thickness, the proba- 
bility is that the mean thickness of the much finer particles in the glow-causing 
stratum lay between gg^^o and ^oo\)oo ^^ ^" i^^^^- Particles thinner than ^ooooo ^^ 
an inch would not be effectual in reflection, except, perhaps, from their edges, but might 
absorb some portion of the spectrum. In this way the light reaching the reflecting 
particles may have been altered by transmission through the smaller dust. As before 
stated, the microscopic examination of pumiceous matter reveals remarkable facts 
regarding its constitution. High microscopic powers show in a slice of lava cloudy 
patches, which can be resolved into distinct particles only by still higher powers.* 
These particles seem to consist of very minute crystals or embryo crystals. The majss 
of matter ejected from a volcano like Krakatoa and disseminated in the upper air 
may consist of similar vesicles or fragments blown out without the opportunity of 
conglomerating in the liquid state, and the size of the particles would correspond 
with that required to produce the atmospheric effects. 

The after-glows of 1883, when at their maximum, presented certain features 
which indicated that they might be due not wholly to transparent reflecting surfaces, 
but partly to small dust of a more ordinary kind. Thus the visibility of the glow 
over a large part of the sky, and its occasional appearance even at the zenith, might 
be produced by diffuse reflection, and not by the regular reflection of vitreous particles. 
These non-transparent particles might be much smaller than the regular reflectors, 
and still reflect any light which fell upon them; t while even smoke has some reflective 
power in strong light. But opaque dust is not necessary, and would hardly have 
been adequate to produce all the observed effects ; and here, again, we may note that 
thin and lofty clouds reflect red light after sunset, from all parts of the sky. 

The question of the floating power of small particles, such as those which pro- 
bably composed the haze in the present case, is dealt with in Section VII., p. 441. 

The capacity of the stratum largely to reflect light of all colours is shown by 
the change of colour of that part of it which was overhead, from rose tint to pink, 
orange, yellow, and finally white, just before sunrise, and by its occasional appearance 

• JuDD, * Volcanoes.' 

t Fabadat, * Researches in Chemistry and Physics, Bakeriau Lecture. 1857.' 



ON THE CAUSE OP THE UNUSUAL TWILIGHT GLOWS. 189 

as a white rippled haze in daylight, soon after sunrise and before sunset, in England. 
The green coloiu* never appeared overhead just before sunrise, probably owing to 
the masking effect of the blue sky, which was then strongly illuminated. The 
sky is at all times much greener towards the horizon than overhead, where there is 
not a sufficient thickness of lower air to cut off the more refrangible rays. 

A very interesting consideration is suggested by the disappearance of the white 
stratum in full daylight in most parts of the sky in November and December, though 
cloud-like in apparent density an hour before sunrise. It seems that as long as light 
shone upon a veil of dust at a great altitude, and not much upon the air below it, the 
greater part of the matter which makes our sky appear blue was ineffective ; but 
when the sun's rays traversed the whole intervening region, the blue-scattering 
particles became a veil for the white above. It is known by observation on the 
high Andes that, at 20,000 feet, the blue of the sky tends to become dark blue 
or black, thus showing that a large proportion of the colouring matter lies below 
that altitude. Thus we may assume that nearly the whole of the matter concerned 
in producing the ordinary blue sky was below the stratum, and if this assimip- 
tion be a true one, the disappearance of the white stratum in full daylight is 
explained. 

The silvery, glare in the western sky soon after sunset, with its remarkable lustre, 
would be produced by regular reflection from glassy surfaces, while the sun as viewed 
from that altitude was still several degrees above the horizon. Almost everjrwhere 
the sky tints were noticed as strange, unearthly, ghastly, weird, or awful, and not 
resembling the beautiful sunset colours so frequently tinging the upper and lower 
clouds. In accounts of the phenomena from places widely separated, and from 
August 26, 1883, to January, 1884, we have remarks on the colours of the sky as 
resembling lead, copper, brass, steel, and silver. Common dust would not, so far as 
we know, produce these metallic colours.* During 1885 there was not one sunset or 
sunrise which exhibited any of the strange tints seen in 1883 and 1884 in England, 
and, as a rule, the sunsets even when clear were almost colourless. Taking all the 
evidence into consideration, the twilights of 1883, 1831, and other years seem to 
have owed their specially brilliant character to the minute subdivision of pumiceous 
matter by the disruptive force of steam at high pressure, and for this reason some 
submarine volcanoes may have produced atmospheric effects disproportionate to their 
size and altitude. 

The colours of the western sky, 20 minutes after an ordinary sunset in England, 
are commonly as follows : dusky brown near the horizon^ above that dull red, 
reddish or orange, pale yeUow, dull greenish-blue, blue ; these colours being either 
duU and ill-defined, or very pale and clear. The colours are very seldom anything 
but pale and ill-defined when there are no clouds, and often there is scarcely a trace 
of anything but grey and blue. At the maximum of the glow phenomena the above 

* KiESSLiNG experimentally produced similar met-allic tints with transparent minute particles. 

2 C 



190 THE HON. ROLLO RUSSELL 

order was nearly reversed, the colours were far more vivid and prolonged, and of an 
unfamiliar character. There is no record of an order of colours corresponding in com- 
pleteness to that of the glows of 1883.* Von Bezold's description of normal twilight 
does not at all accord with what was then observed. In these glows the ordinary 
colour on the horizon, when visible, was perhaps less bright than usual. No dark 
segment like that described by Von Bezold appeared in the east. No feebly 
illuminated circular disc, sinking fast, was observed. The after-glow occurred when 
the sun was 4° or 5° below the horizon, and sank only slowly. No " second dark 
segment '' appeared in the east, unless the absence of colour other than blue, and 
the gradually increasing darkness, may be described as sucL A slight re-illumina- 
tion of the east occurred when the first after-glow had sunk rather low, and then this 
ro-illumination appeared conspicuously in the western sky as the secondary after- 
glow. The differences between the abnormal and the normal twilight may have 
been largely due to the difference of altitude of the reflecting particles concerned 
in them. 

It may be desirable to compare the order of reflected colours from common 
clouds in an ordinary sunset with that observed during the twilight glows. 

On January 31, 1886, the air was clear in the afternoon, with a strong west 
wind and a blue sky, flecked with a few small masses of cumulus. The general 
state of the air at sunset was not unlike that of November 9, 1883, except 
that there were only a very few clouds on that occasion. But on January 31, 
1886, the condition of the upper air was normal, and therefore served well for com- 
parison with the strange developments of colour on November 9, 1883. The sun was 
nearly white about 25 minutes before setting, then light yellow, yellow, orange, and 
red in succession, setting behind a very low and slight bank of clouds. About 10 
minutes before sunset the small cumuli in K, N., S., and W. were light yellow or 
buff on their under surfaces, and gradually turned into a pinkish-yellow and pink or 
red in correspondence with the sun's colour as seen from the earth. They lost their 
colour just after sunset, showing their low altitude. A long, narrow cloud in the west 
was much brighter directly above the place of sunset than towards north and south. The 
sun set at 4.45. At about 4.50 the little cumulus masses in the east began to timi 
ashy green,t in correspondence with the brighter and clearer green of the sky above 
the place pf sunset. At about 4.56 the eastern sky, beyond the little clouds near the 
horizon, began to show a slight, dull, pink flush ; and this grew up, and at about 5.7 
showed itself on the western horizon, and then the greenish colour of the ciunuli east- 
wards was succeeded by a'pale pink which attained its maximum with the maximum red- 
ness on the western horizon, which was never more than a pale and weak illumination. 

* See LiAis's acconnt of a voyage to Rio Janeiro in 1858, * Comptes Bendns,' t. xlyiii., p. 109. 

t The " Ix)ichenfarbe " of observers in the Alps, where the high snowy tops turn red soon after 
sunset, then ashy pale, and then again red (see Db La Rive, ' Bibliotheqne Universelle,' xxiii., xxiv., 
1889, and Necker, * Annales de Chimie et Physiqne,' 1839.) 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 191 

There was a slight pinkish light still in the west at 5.30, and a very faint pro- 
jection of pink rays. The deep blue sky overhead, at 5.20, shaded towards the west 
into blue with the slightest visible tinge of purple. The succession of colours, there- 
fore, with cumulus is not unlike that in the sky diu-ing the strange glows, but 
the duration is very much shorter. In both cases the phenomena seem to be due 
mainly to reflection of the sun's changing colour in setting, and next, of the light 
reflected by the sky in the west, when the rest of the sky is already darkened. 

In the case of a high stratum of gauzy cirrus which occasionally, though 
rarely, covers the sky, some changes of colour occur similar to those of 1883, though 
the duratioQ of the colours is much shorter. Thus, on December 16, 1885, at Rich- 
mond, in Surrey, the eastern sky was suflfiised with red 40 minutes before sunrise, and 
afterwards with yeUow ; but the green and the metallic tints were absent, and the 
areas of colour were far less definite. 

Cirro-cumulus covering the sky, with the exception of a clear space in the west, at 
sunset, produces splendid effects when the sun sets clear red, the sky appearing like a 
sea of fire, but the condition is of short duration. 

A possible cause of the pinkish light which is occasionally seen in the sky 
after sunset in summer and autumn in Switzerland, may be the presence, at a 
high level, of Sahara dust, which could travel the distance in a very short time, and 
is known to affect the atmosphere far out in the Atlantic, sometimes even to the 
extent of being visible and collected as dust. Off the west coast of Africa, near 
the Cape Verde Islands, when a certain wind blows from the land, the air is filled 
with fine dust, which is deposited hundreds of miles out at sea, and the sun then 
sets deep red, or disappears in a kind of bank at some altitude above the horizon. 
At the edges of the area thus affected, or where the dust is less thick, a red 
coloration is sometimes seen in the sky long after sunset.* 

The red twilight of Egypt and North Africa, and on the borders of the desert, 
prevails especially in the summer and autumn, and appears to be caused by the rays 
of the sun, which has set red at the earth's surface, stiU illuminating the minute dust 
which pervades the air up to a considerable height at that season. 

ARAGOf explains as follows the prolonged twilights of 1831, which accompanied 
the dry fog of that year : — " If the fog reflected that light, it necessarily occupied in 
the atmosphere, or beyond its limits, regions extremely elevated, but yet not so much 
as would be deduced from the ordinary calculations of twilight ; which calculations, 
in effect, are based on the hypothesis of a simple reflection ; whilst it can be proved 
by recent experiments, of which it is not possible here to give an exact idea, that 

♦See LiAis, in *Comptes Rcndus' xlviii., p. 109, respecting phenomena in Atlantic, July, 1858. 
See alao Howard's * Climate of London,' vol. iii., pp. 48, 49, 192. Also the log of the Viola, May 24th, 
27tb, 1883, quoted in Section II., ' General List,' p. 265. 

t Arago, * On Comets.' Translated by Gold, 1833, p. 85. 

2 C 2 



192 THE HON. ROLLO RUSSELL 

oompound or multiple reflections play the greatest part in all the phenomena of 
atmospheric illuminations. When it is agreed that the fogs shall be considered high 
enough to explain from them the existence of the strong nocturnal lights which were 
observed in Berlin, Italy, &c., the red colour of that light, however intense it is 
supposed and has really been, causes no farther embarrassment to the naturalist, and 
I shall not be delayed by it." 

On December 13, 1856, during a fall of ashes from Cotopaxi, 30 miles distant, 
a purple sky was noted.* 

The remarkable skies of Peru and the Pacific westwards, the arrebol of the 
coast of Brazil, and other unwonted twilight colours, are noticed in Section IV., p. 342. 

The following observations made in Ceylon tend to confirm the supposition that 
the after-glow3 owed their colour to reflection of the sun's setting light : — 

" Neither we, nor any who have yet recorded their observations, can remember 
the zodiacal light being coloured green. There was the persistence of the colouring for 
three successive days, too.t . . . 

" The sun seems to have quite recovered his brightness, and all signs of the 
peculiar green or bluish appearance he presented a few days ago have vanished. For 
the last evening or two, however, a remarkable lurid glow, as from an immense con- 
flagration, has been noticeable all over the western sky long after 8unset."J 

Thus, while the sun remained blue or green at setting — that is, from September 
9 to 12 — the sky seems to have been coloured green after sunset, and when the sun 
resumed its red colour the red after-glow became conspicuous. 

'* On the 13th and 14th [September], at about 7 in the evening [about an hour 
after sunset], the western part of the horizon was lit up by an unusual brilliant 
red light. It lasted for about a quarter of an hour or so, and then gradually 
disappeared. "§ 

" Yesterday morning, when the sun rose a little above the horizon, it looked very 
beautiful, being of a soft greenish tint ; and as it set, instead of the golden streaks it 
leaves behind, we saw only a sort of greenish light. It still continues the same."|| 

Other observations, however, in both hemispheres show that on several occasions 
the sun towards setting was blue or green before a brilliant red or orange twilight 
coloration. On September 3, at 7° S., 33** W., the north horizon was very red at 
4 a.m., and at 7 a.m, the sun was pale blue. On September 3, at 3° 6' S., 27° 4' W., 
the haze was fiery red before sunrise, and the sun, when it appeared, was white. On 
September 10, at Bellary, for three-quarters of an hour before setting, the sun was 
green ; after sunset, for fully 40 minutes, the whole western sky was lighted up by a 

* * Nature/ vol. xxix. (1884), p. 612. 

T 'Ceylon Observer,' September U, 1883. 

X '* Star-gazer," in letter dated Pallai, St^ptember 14. * Ceylon Obsei-ver,' September 20, 1883. 

§ * Times of Ceylon/ September 20, from Jaffna. 

II 'Times of Ceylon/ September 28, 1883. 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 193 

brilliant red glow. At Poochin, on September 10, a pale green sun and red sky are 
reported. On September 11, in the Red Sea, the sun was green at rising and setting, 
and there were bright after-glows, the order of colours from the horizon being yellow, 
orange, red. At Madras the sky, on September 12, 1883, was of an intense reddish- 
yellow colour at 5 a.m., and at 5.26 a.m. the east was deep red, and the rest of the 
sky greenish-yellow. The sun rose at 5.50 of a bright yellowish- white colour. Thus 
there can be no question that a white, green, or blue coloration of the sun near the 
horizon was not incompatible with an antecedent or a subsequent red coloration of 
the sky. Conversely, in England, the sun, immediately before sunrise and aft.er 
sunset, as a rule, rose and set red or orange, and yet a part of the sky was coloured 
green or greenish-yellow. 

But, as a rule, the fore-glows and after-glows were far brighter and redder where 
the haze was not very dense and where the sun rose and set of the usual colour. 
Good observations in Ceylon and elsewhere make it plain that the sun in declining 
changed from blue to green and greenish-yellow, and conversely from yellow to blue 
on rising, so that we may fairly assume that at a great altitude, where the setting and 
rising sun would be shining through a much greater length of lower air, the colour 
last at sunset and first at sunrise would sometimes be red. In fact, it is clear that 
the maximum comparative influence of the foreign stratum, which tended to make 
the sun blue, would be exerted, not at sunrise or sunset, but some time after sunrise 
and before sunset, at the lower surface of the haze at the high level. On very many 
occasions the sun was not seen on the horizon at all from the earth's surface during the 
period of blue-sun phenomena, and therefore, as its last visible colour was green, it 
would be described as setting green. But where the view was unobstructed, and 
when the haze was not so dense as to hide the sun altogether before it reached the 
horizon, the last colour in setting was frequently yellowish -white or yeUo wish-green. 
There is no instance of the sun setting or rising blue on the ocean (where the view of 
the true horizon was unobstructed), and being followed or preceded by a red glow ; 
but there are several observations recording a white, grey, blue, or leaden sky before 
sunrise or after sunset, when the sun appeared white, blue, or leaden. Even if the 
sun, as it sank to near the horizon of the high level, became obscured, as it often did 
on the earth's surface, by the density of the haze, the diffused light transmitted might 
be blue, green, yeUow, and red in succession, for, its declining rays would progressively 
pass through a much greater comparative length of lower blue-arresting air than in 
setting, as seen from the surface ; and the red would become manifest by reflection 
from elevated particles, though the sun had been seen to set green on the earth's 
surface. Only in the early period after the eruption, and where the haze was dense, 
would the red-arresting particles overcome the effect of the ordinary blue-arresting 
particles of the lower air in a line through the atmosphere from the high level to 
the setting sun. 

These considerations may account for the fact that red after-glows were 



194 THE HON. ROLLO RUSSELL 

undoubtedly seen in a few places, when the Bun, not long before eunset, had been 
seen blue or green. In one or two cases the effect may have been owing to the sun, 
after sunset took place on the earth, having passed beyond the overlying stratum and 
having reached, from the point of view of the stratum, a clear space in the far west 
as yet unaffected by its absorptive or scattering influence, whence the sun would cast 
its usual ruddy light on the particles at a great altitude above the western horizon. 
This may have been the condition producing the red illumination at Trinidad on 
September 2 ; and the fiery redness of the sky before the sun rose dazzlingly white 
{Qv£en of Cambria, 3° 6' S., 2T 4' W.), on September 3 may have been owing to 
the sun, before sunrise, having from that position been beyond the eastern limit of 
the great haze stratum. It will be noticed that usually the sky was not seen red, 
but white, grey, or blue before a white or blue rising sun, and after a white or 
blue setting sun; and the exceptions may have been due to the reasons above 
stated. 

North and south of the path of the main body of haze within the tropics, the 
red glows were conspicuous. 

With regard to the objection that a very large quantity of dust would be 
required to be spread over the upper air to produce the glows which covered simul- 
taneously so great an extent of surface, no good ground can be adduced why very 
small particles illuminated on a dark background, and seen through darkened air, 
should not combine to produce a conspicuous effect ; a continuous film, not thicker 
than 0*000,005 of an inch, would be sufficient to reflect a considerable proportion of 
white light. One cubic kilometre of fine dust spread over the upper air would pro- 
duce a continuous thickness of 0*002 mm. = 0000,078 of an inch for the whole 
surface of the atmosphere,* or 0*000,156 of an inch for one hemisphere, which is 
probably a greater surface than was covered at any time by the glow phenomena. 
And a sheet of fine cloud spread like this dust in a lofty stratum over the atmosphere 
would occupy, a« water, a very small cubical volume, but would be capable, in a finely 
divided state, of producing a visibly red sky with the sun several degrees below the 
horizon. 

The tails of comets have been calculated to be of so great a tenuity that the 
matter contained in a tail of 100,000,000 miles in length and 50,000 miles in 
diameter, if compressed, would scarcely amount to a cart-load : the matter causing 
the blue colour of the sky may possibly occupy a still smaller volume.t A strong 
optical effect may thus be produced over a vast space by an extremely minute 
quantity of matter ; whUe the distance of the stratum from us cannot be compared 
with that of comets. 

There appears to be very great probability that a quantity of fine dust pervading 

♦ Ybrbeek's * Krakatau,' p. 157. 

tTTNDALL, "Scientific Use of the Imagination,** * Fragments of Science/ p. 122. See also 
IlEKScnsL's ^ Astronomj.* 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 195 

the upper regions of the air would, according to the experiments of Mr. Aitken, 
condense upon itself the vapour with which it came in contact, and that, with this 
augmentation in size, the particles would become visible, as thay were in the twilight 
phenomena. In the present case, however, spectrum observations and the nature of 
the corona, as well as other considerations, do not support this view, as representing 
what actually occurred. Moreover, we have had experimental demonstration on a 
grand scale of the competency of dry dust to produce ^(JuaJly remarkable atmospheric 
effects. In 1783 Europe was covered with a dense dry haze for several months 
during the summer, and the sun was shorn of its rays during a long period of dry 
weather. The haze extended from the sea-level to an elevation higher than the tops 
of the Alps. It followed a great eruption in Iceland. Any stratum of this haze — say 
5,000 feet in thickness — would probably have produced twilight effects like those of 
1883 if it could have been raised to a sufficient height and the lower air had been 
clear. The air was too dry at that time to permit the supposition that the dust 
particles were loaded with water vapour. The particles do not seem to have been 
large enough to be visibly deposited and to be examined with a microscope. In 
fact, they seem in character to have greatly resepibled the particles of the haze 
which succeeded the eruption of Krakatog, in 1883, when the dust particles were 
carried to a height where the dryness of the air would be extreme and where 
clouds are never formed. 

Although we do not think that diffraction through the haze-stratum accounted, 
without the factor of reflection, for the series of brilliant colours witnessed in the 
twilights of 1883, it nevertheless played a very important part, just as it does in the 
case of ordinary sunrises and sunsets. According to the law ejaun^iated by Lord 
Raylbigh,* " When light is scattered by particles which are very small compared with 
any of the wave-lengths, the ratio of the amplitudes of the vibrations of the 
scattered and incident light varies inversely as the square of the wave-length, and 
the intensity of the lights themselvea as the inverse fourth power." Consequently, 
the blue rays are scattered laterally, and an increased proportion of red rays is 
propagated in the direction of incidence. The particles of the haze^stratum were 
large in comparison with ordinary atmospheric blue-scattering particles, ayid scattered 
rays of the other end of the spectrum. The remarkable phepomejia of the glows 
therefore resulted from the inter-action of these two oppositely-working layers upon 
transmitted rays, with the aid of a lofty reflecting di^strcloud not usually present. 

Thus we may probably conclude, that the haze which followed the eruption 
of Krak^toa, and produced the twilight glows, w^s compQse4 mjg^inly of very fine 
dust, and that this (Ju9t at a great altitude reflected the light of the setting or 
rising sun after diffractioiiL through the stratum and diffraction and absorption by 
the lower atmosphere, and secondarily reflected again this reflected light. 

* 'Phil. Mag.,* vol. xli. (1871), p. 111. 



J 



196 PROFESSOR KIESSLING 

Tlie foregoing remarks may therefore be summarised as follows : — 

1. The fall of dust, chiefly pumiceous, at great distances from Krakatoa west- 

ward, on the days following the first appearance of the red twilight. 

2. The existence of a white haze at a great altitude during their prevalence. 

3. The great effect produced by small vitreous surfaces in reflecting sunlight 

when the intervening air is darkened. 

4. The failure of the spectroscope, on the whole, to indicate an increased 

strength in the lines due to vapour. 

5. The structure of the haze, more resembUng that of smoke than that of the 

highest clouds. 

6. The resemblances and contrasts between reflection of sunset rays from 

thin high clouds and from the haze stratum, both in the first and the 
second after-glows. 

7. The sequence of colours con-esponding with what might be expected to be 

the changes of colour due to the sinking or rising sun at the altitude of 
the stratum. 

8. Previous effects seen in years of great eruptions, especially 1831, and in 

places affected by an excess of dust in the air. {See also Section V.) 

9. The extreme lightness of pumice dust and the theoretical floating power of 

fine particles, {See also Section VII.) 

F. A. BoLLO Russell. 

Professor Kiessling*s Theory of the After-glows * 

Herr Eiesslino has made a number of laboratory experiments largely based on 
the discoveries of MM. Couijer and Mascart, and of Mr. Aitken, regarding the 
power of dust to attach vapour to itself, and has extended his researches to the effects 
produced by small particles on rays of light. He states that fog consists of watery 
spherules, the difference in their sizes making it colourless by the overlapping of 
numberless diffraction rings. When only a few cubic millimetres of common dusty 
air are introduced into a vessel containing dust-free saturated air, a silvery trans- 
parent mist forms, and when the sun or the electric arc is looked at through this mist 
it appears surrounded with a bluish or greenish briglit sheen with a broad reddish 
ring, exhibiting all shades from glowing purple to the lenderest pink. These diff- 
fraction colours appear with a peculiar metallic glare. The smoke and dust particles 
of the atmosphere would arrange themselves, according to their weight and 8ize, 
in layere. As the sun goes down, therefore, the particles above being smaller than 
those below, the ring appears larger over the setting sun than under it. The lower 

• Abstracted from 'Die Dammerungserscheinungen im Jahre 1883*; see also *The History and \^'oik 
of the Waruer Observatory, Rochester, N.Y., U.S., 1883-6.' 



ON- THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 197 

layers also absorb Dearly all the light, so that the white spot appears only above the 
sun. He says : — " All the twilight phenomena may be explained by the action 
of fine equal-sized particles of dust." From his experiments he finds that the 
difltaction of the most strongly difiracted red rays does not exceed 25° to 30° from 
the direction of the sun's incident rays. The red colour, therefore, would appear 
at about that distance, while nearer the sun there could be no colour effect, 
because the rays would be passing through layers of dust of very different sizes. 
Within the cone of light, that is, in a line drawn to a point within 25° or 30° 
of the sun, the rays meet with particles so various as to re-combine the diflBraction 
colours. The result would be a white or grey sheen. When the sun has set 
on the earth's surface there will be no colour effect so long as the atmosphere 
is strongly illuminated, on account of the general scattering of light, which prevents 
the action of the upper stratum from becoming apparent. The maximum effect 
will take place when the sun has sunk so low that a part of the upper stratum 
between the west horizon and the zenith is receiving rays parallel to itself; 
and then, the particles being of the same size, the diffracted rays will pass downwards 
at the same angle and reach the eye of the observer further east, already in deep 
shadow. From this mist zone, which is, in accordance with laboratory experiments, 
so transparent as to be usually invisible, coloured diffracted rays proceed, and produce 
first an effect of colour east of the observer, where they illuminate the lower 
vaporous layers, the colour becoming stronger with growing darkness ; and, secondly, 
after about 15 to 20 minutes, an appearance of luminous colour between the zenith 
and the west horizon, the diBfraction rays now passing straight to the observer's eye. 
The uncommon prolongation of the twilight by the second after-glow seems to depend 
on a very diffuse and uniform mist, those strata exercising a considerable diffiuctive 
power which are at the outer border of the segment reached by direct sunlight, so that 
rosy di&acted rays penetrate into the dark so-called earth-shadow, and light up the 
vaporous matter there. The second rosy after-glow, therefore, will be seen when the 
background, on which the very weak diffuse light is set off, is quite dark — that is, 
when the greater part of the atmospheric arc lighted by the sun has sunk below the 
horizon. The extent and intensity of the first and the second after-glow must, 
according to experiment, depend very decidedly on the homogeneity of the mist. 
When a glass vessel is filled with homogeneous mist — so that, for instance, an electric 
light appears as the centre of a green sheen surrounded with two red and violet 
rings — and a few cubic millimetres of tobacco smoke are introduced, the splendid 
colours are at once lost in a dirty yellowish colour, with a reddish border. [The 
suggestion presents itself in connection with the above argument whether the rusty 
colour of the moon in a lunar eclipse may not be due to the diffraction of rays which 
have passed through the earth's atmosphere.] Prof Kiessung then remarks on the 
absence of the defined earth-shadow, during the displays of 1883-4, noticed also by 
Dr. VON Bezold. Prof. Kiessung concludes that only two causes, either dust or 

2 i> 



198 PROFESSOR RICCO 

homogeneous water particles produced by the finest dust, could have given rise to 
the after-glows. He thinks it not at all improbable that by the sifting action of 
months, the dust of Krakatoa should have become so homogeneous as to account for 
all the effects. He has seen the diffraction rings even in cement dust sifted through 
fine muslin. 

Although Professor Kiessling's theory accounts for the solar corona, which 
appeared more distinctly several months after the eruption than at an earlier date, it 
fails to explain points of great importance in the twilight phenomena. The glows 
were seen on the day following the eruption and continuously thereafter. The 
particles could not so early have become sorted into layers of equal-sized dust. 
The diffraction ring was often visible after sunset in England, but seemed to be a 
distinct phenomenon from the brilliant colorations which followed the paler hues 
of diffraction.* Prof. Kiessling accounts for the secondary after-glow by the 
reflection of the first glow ; so that he assumes a capability of reflection in the 
stratum of considerable effective strength. But if the stratum be capable of 
reflecting so conspicuously the sinking arc of the primary after-glow, will it not, 
(I foi'tiori, reflect the direct rays of the setting sun ? And if a stratum existed 
of density sufficient, as we have seen, to make the sky appear overclouded at 
certain stages of the twilight, we cannot avoid the conclusion that this stratum 
would be capable of strongly reflecting the red light of the setting or rising sun, 
the intervening air being deprived of its masking glare by the earth-shadow. Now, 
the time at which the afterglows appeared corresponded with the period after 
sunset at which the diffused matter, from other considerations respecting its height, 
might be expected to receive the hist rays of the setting sun. And finely divided 
solid or liquid matter has firequently been proved to be capable of so reflecting the 
sun's last rays. It therefore does not appear probable that difiraction was con- 
cerned in producing the principal effects in the twilight phenomena, though some 
visible influence would undoubtedly be exercised thereby in minute particles widely 
diffused, and in course of time becoming more homogeneous. 

Professor Riccd's Views. 

Professor Ricc6t has, in one of his valuable articles on the twilight phenomena, 
stated the reasons which to him render difficult the acceptance of Professor Kiessling's 
theory of the twilight glows as a part of the corona surrounding the sun. He finds, 
first, that the outer margin of the diffraction corona should be on the horizon when 

• The diffraction colours were occasionally visible when the bright glows were but moderate in 
extent and brilliancy. These diffraction colours were seen as very pale pink and greenish-white arcs 
before sunrise, moving upwards much less rapidly than the bright colorations from which they were 
quite distinct. 

f " Riassunto delle osservazioni del crepuscoli rossi,** * Reale Accademia dei Lincei,' vol. ii, Series 
4a, Session of January 8, 1886. 



ON THE CAUSE OF THE UNUSUAL TWILIGHT GLOWS. 199 

the sun is 26° below the horizon. But in reality the distamse of the primary rosy 
arc, when on the horizon, from the sun was only 9°. Secondly, the rate of descent 
towards the horizon after sunset was much more rapid at first and slower near the 
horizon than would be the case if the arc were a part of the corona, which would 
descend at a constant rate. Thirdly, the change of form and the dimensions of the 
coloured arcs were much greater than can be accounted for by the coronal theory ; 
for, the greater obliquity of the diffracting stratum could not produce such a change, 
as may be experimentally verified. The rosy arc exhibited a great variety of shapes. 
Fourthly, if the rosy arc had been part of a diffraction ring, its colour would have 
been produced by the superposition of red and violet in two neighbomring orders ; 
and in the spectrum, beyond the maximum of red, there would have been a maximum 
of violet, but this was not the case. Fifthly, a corona has frequently been distinctly 
seen by Professor Tacchini and by himself, and has been followed by only weak 
or ordinary twilight. In a former article Professor Ricc6 had remarked on the 
diverging beams as showing that the glow was caused by matter reflecting direct 
sunlight. 



PART IV., SECTION I. (c).* 

The Blue, Green, and otherwise coloured Appearances of the Sun and 

Moon in 1883-84. 

By Mr. E. Douglas Archibald. 

Simultaneously with, and closely following upon, the eruptions of Krakatoa on 
August 26th and 27th, 1883, we have, from different parts of the globe, chiefly within 
the tropical zone, information of the sun appearing blue, green, silvery, yellowish, and 
coppery ; and of the moon occasionally appearing green. 

In Section III. (a), p. 312, of this report, the geographical distribution in space 
and time of these appearances is given in detail. 

In the present section we purpose to give a general description of the phenomenon 
as it was seen in different parts, and briefly to discuss its physical cause and pecu- 
liarities. 

Before alluding to the coloured appearances of the sun which followed the major 
eruptions of August 26th and 27th, 1883, we must advert to some which were seen 
in the neighbourhood of the volcano during its minor eruptions in May of the same 

* In this and sobsequent Sections it should be noticed that positions are sometimes given in English 
notation, viz., degrees and minutes, and sometimes in degrees and decimals — the usual symbols indicate 
which is employed. Moreover, as on some pages it is impossible to place all the references as foot notes, 
it is well here to state that the list of such will be found at the end of each Section. — Ed. 

2 D 2 



^00 MR. E. DOUGLAS ABCHIBALD 

year. Thus, following on the eruptions of May 20-23, we are told * that at Kroe, in 
Sumatra, to the west of Krakatoa, the "ashes were so thick that the sun was 
obscured by them," but in this case no mention is made of the sun being actually 
coloured. The first of these appearances, which is the one most important in its 
bearing on the cause of those which succeeded the major eruptions of August, was 
observed on board the ship Elisabeth, (^)t When in sight of Krakatoa, at 9 a.m. on 
May 20th, a white column of vapour and ashes was seen to elevate itself to a height 
estimated at 11,000 metres, or nearly 7 miles, by measurements effected (apparently 
by the aid of instruments) on board 

" After this followed a rain of a very fine grey-yellowish dust which penetrated 
everything, and which continued to fall until the night between the 21st and 22nd of 
May. On the morning of the 21st the light was that which prevails during an 
eclipse of the sun ; the sky presented the aspect of a large dome of very thin opal 
glass, to the vault of which the sun seemed suspended as a pale blue globe. A fall 
of dust was still observed at a distance of 345 English miles from Krakatoa " (the 
ship was travelling to Singapore). J 

Again, on May 20th, the Actcta, in the neighbourhood of Krakatoa, 6° 50' S., 
101° 2' E., reports " a peculiar light green colour was observed in the sky to E.S.E., 
whUe from E. to E.N.E. there was a dark blue cloud which reached from the horizon 
to the zenith. About 2 p.m. the day was quite dark, and a very fine dust began to 
fall, which covered the ship, and only ceased about 9 a.m. on the 2l8t. The sun 
looked like dull silver. At noon on the 21st, in 8° 15' S., 102'' 28' E., the sky 
remained of a dusty hue. The sky did not assume a natural appearance until 
the 23rd. (*) 

Besides these direct observations of a coloured sun in May, we have the col- 
lateral observations on board the Belfast (0, from May 24th to July 16th, in 
11° 38' S., 31° 44' W., to 8° 52' N., 85° 52' K, of "a prolonged zodiacal %ht 
and other optical phenomena." Then, on July 16th and l7th, the Belfast (^ 
observes " a blue moon after sunset through light haze." 

The preceding observations have been quoted mainly to show the relation ot 
the few cases of coloured appearances of the sun and moon after the minor eruptions 
of Krakatoa in May and June, to these eruptions, and their analogy to the extensive 
series of coloured suns in particular, which were observed after the major eruptions 
of August 26th and 27th. 

Here again we have a few observations near the volcano, in which the 
occurrence of a green sun is mentioned, viz., on August 27th, at Batavia,§ the 
sun was observed to be green after emerging from the cloud or smoke of the eruption ; 

* Vbrbbbk's *Krakatau/p. 15. 

t For numbered and letteied references in this Section, see p. 218. 

X This passage is a fi'ee translation of one in Yerbeek's * Krakatan,' p. 16. 

§ * Batavia Dagblad.' Vebbeek's * Krakatan,* part ii., Notes. 



ON THE COLOURED APPEARANCES OF SUN AND MOON. 201 

and on the same day, and for several days after, it was observed to be green by the 
Hon. F. C. P. Verbkeb, at Labuan Island.* 

In the adjacent districts of Sumatra and Java, the sun was probably too obscured 
during the greater part of the time to be seen at all, and the inhabitants generally 
were too much absorbed in contemplating the other more striking eflFects of the 
eruption to notice the colour of the sun ; but the sky was noticed from Serangt to be 
the colour of lead, and from Teloek Betoeng t to be the colour of copper in the 
direction of Krakatoa. Here we have the first quotation of the colours of two 
metals, afterwards employed in more than one description of the appearance of the 
Sim from the Pacific Ocean and other parts. 

As the geographical distribution of the coloured suns in the tropics is described 
in detail in Section III. (a), p. 312, we shall not here follow their appearances in regular 
succession, but state generally that the results of this investigation prove them to 
have proceeded at first coincidently with, but within narrower limits than, the other 
optical phenomena after August 27th, in their double revolution round the globe, and 
within a zone bounded finally by the north and south tropics. 

Beyond these limits the blue or green appearance does not seem to have 
been witnessed, except sporadically, and in many cases only temporarily, and 
sometimes merely subjectively by contrast with some adjacent red colour of 
the sky. 

In the continuous series the last clear account of a green sun, from a ship near 
the equator, is that of the OlberSy in 9° S., Sb"" W. on September 28th, 1883 ; but 
subsequent to this we have a notice of a pea-green sun at Bangalore^ and again, of 
a green sun in Ceylon on November 9th, 1883.§ 

Also Professor Miohie Smfth, of Madras, seems, after his attention was drawn 
to it, to have noticed a green moon on May 14th, 1884 ; but this is alluded to 
as if it were merely an occurrence which he had hitherto overlooked, and which 
occasionally appears in those latitudes in connection with excessive humidity. 

That in the extra-tropics the coloured sun was by no means generally seen, even 
temporarily, may be gathered from the following remarks ; — 

At Wooster, Ohio, U.S.A., Professor O. N. Stoddard || says : — " In no case has 
the sun during the day, or at setting, appeared green." 

M. P. J. THiiaoK,§ of Nice, says : — " The blue sun has not been observed in 
our high latitudes ; but we have seen the green moon." 

Professor Michie Smith T says : — " The green sun was not seen further north than 

* 'Nature,' vol. xxix. (1883), p. 153. 

t VBfiBBEK*s * Krakatau,' p. 59, Ac. 

X 'Times of Ceylon,' October 6, 1883. 

§ * Lee Illuminations Cr6pusculaires,' April, 1884; Reprint p. 19, 

II 'Nature,' vol. xxix. (1884), p. 356. 

t * Nature,' vol. xxx. (1884), p. 347. 



202 



MB. E. DOUGLAS ARCHIBALD 



Ongole, except at Vizagapatam, Eagamundey, and Simla ; and the dates of observa- 
tions at these stations are not preserved. It was observed at Bombay, but was so 
inconspicuous that it escaped notice at the Observatory." 

In the extra-tropics the coloured sun was seen, noticeably by the following : — 



Duration. 


Place. Observer. 


Date. 


Temporary . . 
At sunset . . 
Temporary . . 


F6toulefl,l8^re» .. . . F. Perrin 
Kalmar, Sweden f • • • . ' ? 

Cracow J Dr. Karlinski . . 

Kersal § (near Manchester) 1 E. J. Bles 


December 24, 1883. 
January 14, 1884. 
January 24, 1884. 
February 26, 1884. 



The moon, likewise, was observed to be green in the higher latitudes by the 
following : — 



Duration. 


Place. 


Observer. 


Date. 


At sunset . . 
At sunset . . 

Temporary . . 
At sunset • • 
3 minutes . . 
3 minutes . , 


Madrid II . . 
Coniston | .. 

— 1 
Worcester || 
Lesina X 

Kalmar jl 

Stockholm || ... 


.! 


F. Gillman 
Arthur Severn . . 
James Macaulay 
J. LI. Bozward . 
Bucchich 

? 

? 


'• 


November 30, 1883. 
December 2, 1883. 
December, 1883. 
December 14, 1883. 
January, 1884. 
January 14, 1884. 
January 17, 1884. 



Though in many of these cases, especially those of the green moon, the colour 

was evidently subjective in contrast with the adjacent rosy-tinted sky, or to an 

eye long accustomed to red light, it was expressly stated by some persons, such as 

J. Macaulay, Sydney Hodges, Dr. Tripe, and others, to be green when no red 

jis present. In the case of the sun, it was evidently due to the presence of 

le same haze which produced the twilight glows and extensive colorations in the 

opics. 

On the occasion of Venus being seen green by Professor Stoddabd,! on 
ecember 28th, 1883, and January 13th, 1884, he says that the light of the planet 
IS struggling through some invisible medium which arrested the other colours; 
d in other cases the presence of the haze is frequently referred to. 

* ' L'Asti*onomie,' 3rd Annee, p. 67. 

t * Les Illuminations Cr^pusculaires,' P. J. Thirion. 

I « Zeitschr. fur Met.,' vol. xix. (1S84), p. 124. 
§ * Nature,' vol. xxix. (1884), p. 427. 

II * Nature,' vol. xxix. (1883), p. 179. 
f * Nature,' vol. xxix. (1884), p. 366. 



ON THE COLOURED APPEARANCES OF SUN AND MOON. 203 

It thus appears that while the material in the tropical zone was dense enough to 
produce a blue or green sun and moon continuously during the first few weeks after 
the eruption, it was only temporarily able to do so in higher latitudes, and under 
conditions which tended to produce subjective contrast colours. 

Besides the blue and green colours so frequently spoken of, we have accounts of 
a coppery, a silvery, and even a leaden sun in the tropical zone, and in those parts 
which were reached by the material soon after the eruption. 

One of the first observations of a coppery sun was that made by Professor 
Dixon at Tokio, on August 30th. (') This is especially interesting in connection with 
the exceptional transmission of a narrow stream of the haze towards this region, vid 
Labuan Island and Fisher Island, since it leads us to conclude that this stream must 
have been of some considerable density. Similar coppery colours were witnessed 
only close to the Equator, where the main stream which travelled westwards was most 
dense. For example, it was seen besides only at 

(1) Fanning Island, Sept. 4. 

(2) 1^ 20' S., 21° W., on West Coast of Africa {Corona), Aug. 31. 

(3) Guayaquil, 2° S., 80° W., Sept. 1. 

In the case of one ship, the Frieda Grampp (*), the sun was described as for 
days together looking like a leaden plate. Such colours, however, were only 
exceptionally observed, and the sun was generally described as being silvery, blue, or 
green. 

In order to see whether there was any relation traceable between these different 
colours and their distribution with regard to locality for the first ten days succeeding 
the eruption, we have placed them in three groups below : — 



204 



MR. E. DOUGLAS ARCHIBALD 



The Sun was observed — 



Date. 



Bine. 



Qreea. 



Aug. 27. . ! Kokknlai (*), Ceylon. 



,. 28.. 

„ 29.. 

„ 30.. 

» 31. . 

Sept. 1. • 

11 2, . 



3.. 



Batavia (*). 
Labnan 
Bangaey Island 



jo- 



Kokknlai. 
Kokknlai. 
Kokknlai. 
Kokknlai. 

Kokknlai. 

Cape Coaat Castle (*). 

Ship lO** 40' N., 26** 30' W. 



Bogoti (•), 4° 43' N. .74* 12' W, 

Maracaibo, ll** N., 72^ W. 

Kokknlai. 

Paramaribo (•), 6* N., 55^ W. 

TrinidadC), 10° 30' N., 61° 20' W. 

Medellin (•), 6* 2' N., 76° 49' W. 

Ecnador (•), 3" S., 76"" 30' W. 

Cape Coast Castle. 

San Chmtobal (•), 7^ 30' N., 

72** 23' W. 
Campano, 10° 36' N., 63° W. 

Maracaibo. 
Kokknlai. 



Kokknlai. 



Maracaibo (*). 

ZeaUndia, 5^ N., ? 170° W. 



„ 6. . I Strong Island (silver bine), 
I ("), 6° N., 163** 6' E. 



„ 6. . I Zealandia, 6° N., P 170 W. 



Cartagena (•), 10*^ 22' N., 

75° 32' W. 
Panama O, 8** 59' N., 

79* 32' W. 



Panama (^). 
Medellin, Columbia. 



Jennie Walker(% 8° 20' N., 
155° 28' W. 



Silvery. 



Ida, (•) l°-3 N., 108°-4 E. 

AlbeH BeifMLun (•), 2°-3 S., 4°-7 

Maranham («), 2° 30* S., 44° W. 
(pale snn), and 2° S., 5° E. (•). 

Gaayaqnil (*»). 

Maranham. 

Queen of Cambria (0, 9° S., 

28^ W. 

Varinas (Veneenela), 8°-6 N., 
70° W. (blnish-green 3 p.m. 
to 5 p.m.). 

Onajaqnil. 

Maranham. 



Colombo ("). 
Honolnln (»). 



Onayaqnil. 
Maranham. 

0U>er8 (pale bine), ('), T'2 S., 
33° W. 



Maranham. 

Snperb, 13° 17' S., 149° W., and 

for three days thenceforward 

to 5° S., 148^ W. 
Tapitenea, 1° 10' S., 174° 50' E. 



Sttperh, 

Papa (•), 8°1 N., 161°-4 W. 
(pale as throngh bine glass). 
Ms^nham. 



ON THE COLOURED APPEARANCES OF SUN AND MOON. 205 

Thenceforward we hear little more of a " silvery " sun, and the colour appears to 
have been mainly green. From the above lists it appears that the " blue " sun was 
chiefly seen at great distances from Java, especially if Kokkulai be omitted as giving 
positive evidence of its having been seen in the Indian area, the word nil for blue 
and green being the same in Singhalese."*^ The "green" sun was visible at first only 
in the Indian Ocean, but afterwards more generally than either of the other colours, 
and finally the " silvery " sun, when at a high altitude, appears to have been almost 
entirely confined to a narrow zone near the Equator, and more especially, on its 
southern side. If to this we add the cases in which the sun appeared coppery, 
dim, and sensibly obscured, we find that they were all t close to the Equator in 
each hemisphere. 

In several cases the sun was not visible when near the horizon. Thus the 
Papa, (•) in 0"" I'S., IGS"" 7' W., reports that the sun on September 9th was hidden 
in the yellowish veil up to 7° above the horizon; and in 1° 5' S. and 165° W., the 
captain of the same ship says that the sun was still veiled with a yellow stratum. 
In other parts, where it was reported to be green • or blue at high altitudes, 
it was several times spoken of as being dim and giving little light until it had 
reached an altitude of 10° or more. Further irom the Equator, or from the latitude 
of Krakatoa, the green colour seems to have been visible only when the sun was at a 
low altitude. 

Thus, in Ceylon, at Colombo, on September 9th, the sun was observed to be green 
when about 10° above the horizon. (*^) Also, on September 10th, the Belfast , in 
18° N., 86° E., reports the sun as blue like the moon, at 4 p.m., changing to green at 
sunset. (^ 

On September 10th, at Madras, the sun was observed to rise of a bright blue 
colour, and the phenomenon lasted from 6 to 10 a. m. (^^) 

On the 9th, from the Pelican, 10° 4' N., 64° 13' E., the sun was noticed to be 
gi-een in the morning, (^*) and also throughout Southern India and Ceylon, chiefly 
in the mornings and evenings. {^^) 

Mr. Ladd, while passing through the Red Sea early in September, 1883, noticed 
that the sun, after rising and before setting, and the moon before setting, were 
observed to be green at an altitude of 20° to 25° above the horizon ; and he noticed 
a point important in its relation to the other phenomena, viz., that on the first 
occasion " the green moon was covered with thin cirro-stratus, over which the after- 
glow was cast." (*®). 

At Madras, on September 12th, it was noticed that the moon, when near the 
horizon, became a pale green, and bright stars near the horizon showed the same 
tmt. (") 

Similar accounts are given elsewhere. 

• • Ceylon Observer/ September 16, 1883. 
t With the exception of the coppery son in Japan. 
2 E 



206 MR. E. DOUGLAS ARCHIBALD 

Thus, on September 4th, in the Pacific, the Jennie Walker observed the sun 
green at setting. (•) 

At Fanning Island, on the same date, the sun was copper coloured, and on 
September 17th the Superb^ in 12° N. 146° W., reports the sun when rising to have 
been like a green ball. The Scotia 12° N. 51° E., observes "the sun green on 
rising " on Sept, 9th. 

At Buenos Ayres the green colour seems to have been noticed up to 20° or 30° 
above the horizon. (•) 

All this leads us to inquire more closely into the question whether the particular 
colour observed was not in part a function of the altitude of the sun above the 
horizon. 

The following circumstances appear to support this notion : — 

At San Christobal, on September 2nd, it was seen to be " silvery at 3 p.m. ; 
then it became bright blue, and lastly sky blue. At 5 p.m. everything looked blue." (•) 

At Cape Coast Castle, on the 1st or 2nd of that month, the sun was described as 
being blue in the morning. It seems that it, on rising, resembled the moon, and that 
the clouds which passed over it, from their greater rarity or their density, gave it 
different apparent shades of rose colour, pink, and so on. After the passage of the 
clouds, its appearance through the haze was white, like the moon. In fact, an 
Englishman is said to have taken it for the moon. (*) 

At Barbadoes it was observed to be " variously coloured during the day." 

The Rev. W. R. Manley, writing (^®) from Ongole, says : — 

" On September 14th we had the curious phenomenon of a greenish colour in 
the light of the sun. . . • About 4 o'clock an indistinct bluish tinge appeared in 
the light. This gradually passed into a greenish colour, and this in turn became 
tinged with yellow as the sun approached the horizon. As the sun sank, bands ot 
smoky haze drifted across its disc. After the sun was down, bright yellow, orange, 
and red appeared in the west, a very deep red remaining for more than an hour after 
sunset. At night, the moon, just past the first quarter, was seen surrounded by a 
pale greenish halo, about 30° in breadth." 

Another similar and important observation (^*) was made in Ceylon by a Govern- 
ment oflScer while travelling from Mannslr to Trincomalee, and is dated Puleadierakam, 
September 12th. "The sun for the last three days rises in a splendid green when 
visible, i.e., about 10° above the horizon. As he advances he assumes a beautiful 
blue, and as he comes further on looks a brilliant blue, resembling burning sulphur. 
When about 45° it is not possible to look at him with the naked eye ; but even 
when at tlie zenith the light is blue, varying from a pale blue to a light blue later on, 
eomewhat similar to moonlight, even at midday. Then, as he declines, the sun assumes 
the same changes, but vice versd. The moon, now visible in the afternoons, looks also 
tingad with blue after sunset, and as she declines assumes a very fiery colour 30° 
from the zwith," 



ON THE COLOURED APPEARANCES OF SUN AND MOON. 207 

We have quoted the foregoing observations in extenso since they evidently agree 
in showing that the colour changed according to altitude, being blue or paJe near the 
zenith, and changing thence through a more brilliant blue to green at from 10^ to 20° 
above the horizon. 

When the sun was below the horizon the rays from it were often in turn 
coloured yellow, orange, and finally deep red. 

At Medellin we hear of even a violet, as well as a blue and green, colour having 
been witnessed. Obviously, then, here we have a case of differential selective absorp- 
tion, the colours, from the zenith downwards, being arranged in spectral order. If we 
imagine the haze which gave rise to these peculiarities of transmission to be composed 
of particles capable of stopping the rays at the red end of the spectrum relatively 
more than those at the violet end, the phenomenon admits of a fairly simple explanation. 

Up to the present few experiments appear to have been made to determine the 
precise tints transmitted by dust of different kinds when exposed to solar light ; 
and to ascertain what proportion of the result is due to diffraction and what to 
intrinsic absorption. Faraday's experiments* on the colour of gold and other metals 
have reference only to matter of intense opacity ; but the matter which gave rise to 
the present phenomena had little opacity, and therefore there is little or no analogy 
between the colours transmitted by metals or oxides in a fine state of divisioii and 
those produced in the present case, probably by some special absorptive property of 
the dust. 

As the particles which, in the present case, produced the transmissive effects, 
may have been different from thosje which fell in the neighbourhood of the volcano, it 
is impossible to infer what their optical properties were ; but it is probable that for 
the most part they were similar to the highly vacuolated vitreous bubble plates 
described by Messrs. Murray and Renard as forming the major part of the ejecta 
from Krakatoa and appearing as grey-green pulverulent matter. 

Whether such matter possesses special absorptive and transmissive properties 
or not we are imable to say, nor can it be determined untU experiments have 
been made with specimens of it ; but if the mere question of size would tend to 
determine selective transmission, we might suppose that at first, and where the 
stream was densest along the Equator, there was a suflficiency of both the larger 
red-arresting, as well as of the smaller blue-arresting particles, to produce a general 
absorption, and thus a silvery light; that, further off, where the stream was less 
dense, at first there were enough of the larger red^arrestipg particles to cause a 
blue sun, when the sun was still high in the sky and shining through only a com- 
paratively small thickness of the stratum. As the sun sank towards the horizon, and 
its rays became more obKque, they would traverse a larger extent of the lower 
atmosphere containing more particles of vapour and organic dust, which generally 

* * Phil Trans,' 1857, p. 145. . 
2 E 2 



208 Mil. E. DOUGLAS ARCUIBALD 

appear by preference to absorb or scatter the blue rays. When the sun was midway 
between the zenith and the horizon, the rays at both ends of the spectrum being thus 
cut off,* the colour would become green ; and finally, aa the sun approached the 
horizon, and the absorption of, and diffraction by, the lower atmosphere became the 
dominant factor, the colour would change, through yellow and orange, to red, as was 
generally observed. 

Even apart from the influence of the lower strata of the atmosphere, the change 
in the thickness of the stratum itself, traversed by the more oblique rays, would help 
to produce the same change in the colour of the emergent light. 

For on the same assumption that the haze exerted a selective absorption on the 
red end of the spectrum, and transmitted the violet end more freely, we should have 
with increased thickness of the stratum traversed by the rays, a tendency to a change 
in the colour of the emergent rays. 

If i li denote the intensities, and a a the co-efficients of transmission of the two 
dominant rays transmitted through different thicknesses. We have for the thickness d 
where the change of colour would occur, 

la' = t a' and.'. 0= ^- ^ , ^ , 

log a — log a 

In the present case, if we assume the sun to be blue at the zenith and green at 
an altitude of 30^, we have 

2= % ^80 - log 168 
log a — log a 
And approximately a :^ a ^/S. 

It is not therefore unreasonable to suppose that the effect of the increased 
absorption of the blue rays by the lower atmosphere, with increased obliquity of the 
solar rays, was partly assisted by the corresponding change in the thickness of the 
haze stratum traversed. 

This would accord with the fact that where the haze was most dense near the 
Equator or the latitude of Krakatoa, and produced a pale or silvery tint when the sun 
was high (owing to its being composed of particles of all sizes, and therefore transmit- 
ting light of all colours), the sun was frequently mentioned as being quite obscured 
when within a few degrees of the horizon, although otherwise the air was quite clear.J 

* That the actual absorption was of this character can be gathered from the paper read by Professor 
MiCHiK Smith before the Royal Society of Edinburgh, July 7, 1884, in which he says: — " When the sun 
was near the horizon, besides the absorption at the red end, there was also absorption at the violet end, 
the spectrum ending just beyond the Jine G." 

t Here *' = 480 for green light, a coefficient for green light, 
i = 168 for blue light, a coefficient for blue light, 
and the value of ^ at the zenith taken as the unit of thickness. At an angle of 30° the thickness 
traversed will be approximately doubled .*. ^ is put = 2. 

X Vide supra, and various remarks in Section I. (d), on sky haze. 



ON THE COLOURED APPEARANCES OP SUN AND MOON. 209 

Subsequently, we must suppose that as the stream of material became more 
attenuated by spreading into higher latitudes, three factors would come into 
play ;— 

(1) The horizontal extension of the haze stratum which would tend to render 

the selective absorption or obstruction ultimately insensible. 

(2) The sifting out by gravitation of the grosser, and therefore presumably 

red-arresting, particles. 

(3) The elimination of accompanying water vapour, if any, by evaporation. 

The combined action of these factors and the changes due to varying solar altitude 
appear to afford a reasonable explanation of the diurnal and secular variations observed. 

The ultimate attenuation of the stratum would partly account for the fact that 
the sun was only rarely seen coloured at all in high latitudes, and then only near the 
horizon, being also assisted in this respect by the time taken by the material to 
spread into higher latitudes, and the sifting out which must then have taken place 
of a considerable proportion of the larger red-arresting particles. 

We have omitted to consider the possible effects of water, either in the state of 
vapour, water-dust, or ice-dust, ejected along with the pumice-dust, because : — 

(1) There is no reason to suppose that it would act selectively on light in a 

different manner from aqueous vapour in ordinary circumstance, which 
generally stops the blue, and transmits the red end of the spectrum. 

(2) Evan if it acted like the ice in a glacier, we should have, by analogy, to 

admit the presence of much more vapoiu: than could possibly exist at 
such an altitude. 

On the whole, it appetars most probable that the dust stratum, when the sun 
was shining through it nearly vertically, affected the light by selective absorption 
chiefly of the raj^s of longer wave length, that as the sun descended, the light 
changed in colour, partly through a change in the thickness of the stratum, and 
partly by the absorption and diffraction through the lower atmosphere, which 
would tend to act in a contrary manner, and eliminate the rays of shorter wave 
length. Finaljy, diflraction through the strcttum and the lower dust, and absorption 
by the aqueous vapour in the lower atniosphere, would completely overpower the 
selective absorption of the stratum, and allow a free parage only to the longer red 
waves. 

Mr. LocKYEB, RRS.j ('') writing on this phenomenon when it was first an- 
nounced, says : — " The ejecta from the volcano, however high they were cast into the 
upper air, would in the first instances have had so much coarse-grainednass about them 
that the light- selecting qualities of the finest among them would have been entirely 
over-ridden by the coarser ones, which would be competent to stop light of every 



210 MR. E. DOUGLAS ARCHIBALD 

kind .... Let this pall become thin. The sunlight will traverse it in part ; 
there will still be general absorption, the sun will be seen white, but dim. Now let 
the coarser particles fall from the upper air, leaving behind only those finer ones, the 
blue and red molecules to which I have previously referred. Neutral tint will now 
give way to green." 

*' Let us assume first that the quantity of red molecules was sufficient to over- 
ride the blue ones. At sunrise the blue molecules from the volcano would be assisted 
in their absorption by the blue molecules of aqueous vapour always present. The sun 
would be green when it first became visible. But let the sun get high ; the absorption 
of the aqueous vapour being then reduced in consequence of the smaller thickness of 
the air as the sun rose, would allow the predominance of the red absorption again to 
assert itself, and the sun would be blue at noon, though it rose green." The red- 
arresting molecules, being coarser than the blue, would " be the first to fall from the 
upper air as dust, so tho^t long after they have sufficiently disappeared to make the 
appearance of a blue or green sun impossible, there would be enough floating material 
in the air at as high a point as the convection currents could have carried it, to reflect 
the sun's light after sunset, and to prolong the twilight in the direct ratio of its 
height above the earth's surface." 

To give a more detailed account than we have hitherto presented of the 
appearance of the green sun in the tropics, we have thought it advisable to append 
hereto the following abstract of a paper read before the Royal Society of Edinburgh, 
on July 7th, 1884, by Professor Michie Smith, of Madras. (-') 

The raritj of the phenomenon of a green or blue sun makes it desirable to record with the greatest 
accnracj and detail the observations made during its appearance in India in the course of BeTeral 
dajs of September, 1883. 

The notes taken at Madras at the time of the appearance will best illustrate the general features of 
the phenomena : — 

On September 9, the sun, before setting, assumed a peculiar silvery appearance, and its brightness 
was so much decreased that for about half an hour before sunset it could be observed with the naked eje. 
This was noticed, I believe, though to a less extent, on the two days preceding, but I did not myself ste 
it on those days. 

On September 10, frpm 5 to 5^30 p.m., the sun could easily be looked at with the naked eye, yet the 
limbs were sharply defined. At 6.30 the sun entered a low bank of clouds, and did not fully appear 
again ; but a narrow strip seen through a rift in the cloud at 5.43 was coloured a bright pea-green. Round 
Madras this colour had been seen in the morning, but in Madras itself clouds concealed the sun till it had 
risen to a considerable altitude. 

Of the morning of the 11th I hare no record, but in the evening the greei}. colour was brilliant, ai^d 
was visible for more than half an hour, being preceded, as on the former night, by the silvery-whitp 
appearance of the sun's disk. Qn this evening a large sunspot, about y long, yrm so conspicuous au object 
that it attracted the attention of even the most casua) observers. 

September 12. — At 10.35 a.m. the moon, 'which was near the horizon, appeared a pale green. Bright 
stars near the horizon showed the same tint. From 5.15 to 5.30 the clouds to the east were coloured 
reddish-brown. At 5.55 the sun rose with a yellowish-green colour, but was almost instantly lost in 
clouds. It reappeared at 6.4^ and i^as then of a bright green colour; this colour i*apidly got fainter, bat 



ON THE COLOURED APPEARANCES OF SCFN AND MOON. 211 

was qaite perceptible till 7 o'clock. In tbe afternoon the phenomena of the previons nights were repeated 
and, the horizon being free from clouds, the actual sunset was observed. The entry in my notes is : 
'^ 6.3. — ^The sun set as a greenish-yellow ball ; cumulus, stratus, and nimbus clouds near the horizon, but 
moon fairly clear ; some blue sky, but hazy." The change from green to greenish-yellow was evidently 
due to the great increase in the strength of the low-sun-band close to the horizon, which left the strip of 
yellow between that band and the rain-band by far the most prominent feature in the spectrum. 

September 13. — In the early morning there was a good deal of distant lightning. The sun rose of a 
bright, golden-yellow colour ; no green was seen. In the afternoon there were slight showers. 

September 14. — Before sunrise the clouds were blue and grey, with patches of red clouds of all 
sorts — cirrus, nimbus, stratus, cumulus, and mares' tails. Two bright flashes of lightning about 
5.30 a.m. In the evening there was a slight green tinge, and after sunset the sky was golden-red till 
6.50, while Mercury, seen through the red haze, was twinkling strongly. 

September 15. — The sun rose golden. In the evening the sunset was very fine : in the west the 
colour was golden to orange-yellow, in the east in was greenish ; red clouds remained till 7.5. There 
were very brilliant red " rayons de crepuscule,*' 

From September 15 to September 20 the sunrises and sunsets were very fine, with red and gold, 
for more than half an hour before sunrise and after sunset. 
September 21. — Sunset normal. 

September 22. — The sun rose as a yellow ball, and showed distinct greenish -yellow afterwards. 
From ten minutes before till sunset the sun was greenish-yellow, but the sun was much brighter than 
on the 10th and 11th. 

September 23. — The sun rose very green. At 5.37 p.m. the sun appeared from under clouds, very 
green ; strong absorption in the red end of the spectrum to C ; low-sun-bands weak. 6.45. — Clouds 
greyish-purple. There was only one bank of clouds which was near the horizon ; above this was a 
peculiar greyish haze. At 6 the clouds were of a marked purple colour ; breaks near the horizon were 
reddish- brown. During the night there was a great deal of sheet-lightning in the south. 

September 24. — The sun rose bright yellow. The spectrum showed complete absorption up to B ; 
the rain-bands a and ^ were very thick, and the low-sun-bands less marked than usual. There was 
lightning all night, beginning in the south and working round to the south-east. It consisted chiefly 
of sheet-lightning, with occasional zig-zag flashes, but no thunder ; the stars were fairly clear except 
near the horizon. Saturn and the moon, when near the horizon, were both very dim. 

September 25. — Sunrise golden-green. In the afternoon the shadows cast on white paper were still 
quite pink, but the sunset was bright yellow. 

September 26. — Much the same as yesterday. 

September 27. — Before suni-ise C, p, a, the rain-band and the dry-air-band were very strong, but 
the dry-air-band was less than half as dark as the rain- band. The sun rose golden-red. The spectrum 
showed signs of clearing up; glimpses of A could be obtained. After dark there was very bright 
lightning in the west. 

September 28. — Spectrum still showed great absorption. Lightning at night. 

September 29. — Spectrum absorption still very strong. After dark there was a display of luminous 
clouds specially towards the east. After 11 p.m. there was very heavy rain, with much lightning and 
some thunder. , 

September 30. — Sunrise golden. The spectrum on the sun showed A clearly, a was very thick. 
October 2. — In the morning, from about 7 to 9, there was a thnnderstorm, in which the thunder 
was almost continuous for about an hour and a half, but although the storm was almost vertical, 
hardly any lightning was visible. . . . The total rainfall for the day was 4*88 inches. 

Accounts were collected from trustworthy observers in various parts of India. All describe the 
brilliant sunsets of the first week of September, and record the appearance of a green sun on several 
days. It was seen at Muttum in the south of Madras on the 9th, and continued for several days both in 



212 MR. E. DOUGLAS ARCHIBALD 

the momiog and in ib« evening. The green coloar was then lost, bnt reappeared from the 22nd to the 
28th inclnsive. 

At Bellary the sun was seen " emorald-g^en '* at rising and setting from the 10th to the 14th 
inclusive. The observations were not carried on longer. 

At Coonoor, on the Nilgiris, the abundance of green tints in the sunsets was noted, but the son 
itself was described merely as of a '* shimmerj *' appearance. 

The Spectrum. — The spectrum of the sun when green was repeatedly observed and photographed 
with the large zodiacal-light sp (metroscope, which is furnished with one large prism of dense ^ass and a 
very long collimator permitting the use of a wide slit. The main features of the spectrum taken on the 
sun when green were — 

1. A very strong general absorption in the red end. 

2. A great development of the rain-band and of all other lines that are ascribed to the presence 
of water- vapour in the atmosphere, more especially of the group C^ of a and of the band at W.L. 504. 

The absorption in the red end was of very varying intensity, but when the phenomenon was at its 
maximum phase it gradually crept up from about B till past C, as the sun sank towards the horiaon. 
On the 12th, when the sun was within a few degrees of the horizon, the absorption was well marked 
up to W.L. 621, t.e.y to beyond a, while at the violet end the visible spectrum ended at W.L. 428, or just 
beyond G. 

The lines A and a were never visible even on the sun when it was green, and even B oould be made 
out with difficulty from half an hour before sunset onwards, and before it vanished it grew intensely 
prominent, with enormously thick bands on the less refrangible side. The band Cj on the more 
refrangible side of C became very broad and black, while the fine line between this and C remained thin 
and sharp, and C itself thickened out on the less refrangible side. The rain-band was stronger than I 
have ever before observed it on the plains, and even with the dispersion produced by a single prism at 
least eight lines could be measured in it, while many more were visible. The low-sun-band was not 
very conspicuous, bnt this was partly due to contrast with the very strong rain-band. The line W.L. 568 
at the more refrangible side of the low-sun-band was very well marked, and the band itself seemed to 
consist of a series of equidistant lines. 

The apparently much stronger absorption in the red than in the blue end was a very marked 
feature, which became still more conspicuous when a photograph of the blue end was examined. 

Since the passing away of the abnormal conditions I have made careful observations of the sunset 
spectrum with the same apparatus, and I find that ordinarily A and a are clearly visible as well as B, 
though at times they are strongly marked, and a good deal of shading is observable between them ; C^ is 
much thinner, and the rain-band is less prominent than the low-sun-band, which, however, does not now 
have the appearance of a number of fine Hues. The nearest approach to the green-sun spectrum was 
observed recently during a severe thunderstorm, which was accompanied by a fall of about 1^ inch of 
rain. A very similar, though less intense, spectrum can be observed almost any evening by taking 
advantage of the passage of a small thin cloud over the sun's disc. If a lens be used in front of the 
slit of the spectroscope, the absor|7tion due io the cloud will be seen as a band in the middle of the 
bright spectrum from the unclouded part of the sun, and owing to the strong contrast, the details of the 
absorption will be well seen, just as in the case of the spectrum of a sunspofc. 

Meteorological Phenomena. — The electrification of the air was carefully studied during the green 
sun period, and the results are rather curious. From September 3rd to Gth the potential of the air was 
positive in the early morning, diminished to zero between 9 and 10 a.m., then became negative, and 
remained so until the sea-breeze came on in the afternoon, when the charge was positive i^z^n. and 
continued so all night. The amount of electrification varied greatly and rapidly. On the 7th and 9th 
the potential was positive all day, on the 8th it was negative for a short time. From the 10th to the 
12th it varied in the same way as from the 3rd to the Gth, and this state of matters was repeated from 
the 20th to the 27th ; the electrometer readings from the 13th to the 19th having been noi*ma1. All the 



ON THE COLOURED APPEAKANCBS OF SUN AND MOON. 213 

negative readings were got daring a hot land wind from the west. Between the 6th and 9th of 
September a storm of unnsoal violence swept over the Madras Presidency from the sonth-west to the 
north-east, making itself felt in different ways at different places. The rainfall for September was 
nnusaallj small all over Madras. The average for fifteen stations was 3*24 inches, not qnite half the 
average for this month during previous years. 

The barometric curves for Colombo, Madras, Belganm, Allahabad, and Calcutta (Alipore) have 
been drawn and found to resemble each other closely. All over India there was a minimum between 
the 6th and 7th, a maximum about the 18th, another minimum on the 21st, then a rise, and a third 
minimum on the 27th. 

The first essential in any attempt to arrive at an explanation of the cause of the green sun is to 
ascertain the precise dates at which the phenomenon was first observed in various parts of the world. It 
is difficult to do this, for peraons are apt to make more precise statements than their observations warrant. 
For instance, the sun certainly set with a peculiar silvery gleam, but no greenness, at Madras on 
September the 9th, and yet many persons have assured me that they saw it set green there on that 
evening. The reason evidently was that after their attention had been arrested by the green sunsets 
of the 10th and 11th they remembered having noticed something peculiar about the sunset on the 9th, 
and immediately concluded that the sun had been green on that occasion also. In consequence of this 
tendency of the mind, the evidence for all the dates given has been carefully tested, and has been found 
in all cases sufficient to justify the opinion that these dates are correct. 

It appears that in Ceylon, in the south part of the Madras Presidency, and at Ongole in the 
north, the sun was first observed to be green on the evening of September 9th, and that over 
the east of the Presidency^ when seen at all, it was first seen green on the morning of the 
10th. The green sun was reported at Belgaum on the 8th, but although the observer was trust- 
worthy, he did not make a note of the fact until afterwards, and it is just possible that it may be a 
mistake. 

The captain of the Cleomene reports a green sun and moon on the 9th, 10th, and 11th, when his 
position was from lat. 8° N. to lat. 16° N., and from long. 83° 30' E. to long. 88^ 40' E. The chief officer 
of the s.s. Pelican saw the moon greenish on the night of the 9th, and the sun green on the morning of 
the 10th. The steamer was more than 1000 miles away from Madras, in lat. 10° 4' N. and long. 64** 12' B., 
wind south-west. 

Amongst the instances In which the sun has been observed of a blue or green 
colour, we may notice the following : — 

The sun was seen blue by Professor PiAZZi Smyth on entering the Bay of 
Palermo, on March 10th, 1872, during a sirocco laden with fine dust. {^) 

Dr. BuDDE, while travelling in South Algeria, in 1880, says that he was assured 
by colonists that the sun seen through the fine dust of a Sahara wind had a decidedly 
blue colour, a fact which supports the view that the green sun in India and the 
paleness of the sun were due to volcanic dust from Krakatoa. (**) 

RiOHTOFEN, in his work on China (vol. i., p. 97), notices that the air in 
Central Asia is filled with dust, and that the sun seen through it appears merely 
as a dull bluish disc. 

Mr. G. F. Chambers, at the meeting of the Royal Astronomical Society 
January, 1884, stated that the "engineer of some works at Eastbourne, at which 
large quantities of sea-beach are crushed by steam machinery, had inibrmed him that 
he had frequently seen the sun appear blue through the fine dust which rises into the 

2 F 



214 MR. E. DOUGLAS ARCHIBALD 

air when the operations are in progress. . . The sun does not usually appear blue 
every evening when it sets, owing to the dust particles being too large, and because 
the aqueous vapour and other gases absorb more blue light than is dispersed by the 
finer particles."* 

One of the most remarkable observations of a blue or green sun, and one which 
possesses a marked interest in its bearing on the connection between these phenomena 
and the eruption of Krakatoa, is Mr. Wuymper's account (") of what he saw duricg 
an eruption of Cotopaxi on July 3rd, 1880. 

After detailing how the smoke was seen suddenly to rise from Cotopaxi, 65 miles 
distant from the party, who were encamped 16,000 feet above the sea on Chimborazo, 
he says : — 

" Several hours elapsed before the ash commenced to intervene between the sun 
and ourselves, and when it did so we witnessed efTects which simply amazed us. 

" We saw a green sun, and such a green as we have never, either before or 
since, seen in the heavens. We saw smears or patches of something like verdigris* 
green in the sky, and they changed to equally extreme blood-red, or to coarse brick- 
dust reds, and they in an instant passed to the colom: of tarnished copper or shining 
brass. . . . The ash was extraordinarily fine. ... I find that the finer 
particles do not weigh the I-25000th part of a grain, and the finest atoms are lighter 
still. By the time we returned to our encampment the grosser particles had fallen 
below our level, and were settling down into the valley of the Chimbo, the bottom 
of which was 7,000 feet beneath us, causing it to appear as if filled with thick 
smoke. The finer ones were still floating in the air like a light fog, and so con- 
tinued until night closed in." He winds up by saying, " The changes from one hue 
to another had obvious connection with the varying densities of the clouds of wh 
that passed.^^ 

Opinions REOARDiNa the Coloured Suns of 1883. 

Mr. A. C. Ranyakd expresses himself to the following effect (^) : — 

As to the suggestion that the blue suns were due to aqueous vapour, the 
heavens in such a case would be covered with cloud ; but the blue suns are not described 
as having been seen through cloud. Many observers expressly state that there was 
no cloud. • . . The blue colour of the sun is easily explained on physical con- 
siderations. In ordinary circumstances there is not enough dust to affect the colour 
of the sun ; but if the amount were greatly increased, the intensity of the dispersed 
light would be increased, and the blue colour of the light dispersed from the part of 
the atmosphere between us and the sun would sensibly affect the colour of the sun. 

Mr. J. Norman Lockyer says (^*) : — 

** Theory had led me to suspect that, with the enormous thickness of air available 

* ' Knowledge/ March 14, 1884. 



ON THE COLOURED APPEARANCES OF .SUN AND MOON. 215 

in India^ abeorptioB at the red end of the spectrum by aqueous vapour would be eeea 
as well as the absorption at the blue, which is so common with us. Seeing the siui 
a vivid green through th^ steam of the little paddle-boat on Windermere first led me 
to inquire into the possibility of aqueous vapour following the same law as that which 
I think we may now accept in the cases of the vapours of metals. As in these 
experiments with vapours, absorption of the red end alone was seen, as well as 
absorption at the blue end alone, the assumption that these two absorptions existed 
in aqueous vapour at once accounted for the green sun.*' 

The same writer says : — 

" Aqueous vapour is composed of molecules capable of stopping both blue and 
red light ; other substances also will stop the red. In ordinary circumstances the 
red molecules of aqueous vapour scarcely ever come into play ; but, if they or any 
siibstance capable of acting in this way should be supplied, the sim would as often 
look green as it does now red.'' 

Professor Michie Smith says (^) : — 

" That the green sun is entirely due to water vapour I am not prepared to affirm, 
for, some observations of Dr. Schuster point to an influence produced by suspended 
matter in the air. 

** Why should vapour if present give green tints ? To settle this point I made 
spectroscopic observations, and, though I have not yet reduced them, I find that they 
indicate a very marked absorption in the red end of the spectrum, extending nearly 
to B, with a great development of the rain-band near D on the red side, accompanied 
by a decided deficiency of the band on the green side, called by Piazzi Smyth * the 
low-sim-band.' Hence we have less red than usual and more green. This is due, in 
part at least, to the sun s light passing through a more than ordinary dense stratum 
of aqueous vapour, for we know that the thicker the stratum of vapour the more is 
the red light absorbed. But this is not all, for we have quite as much vapour 
without this green colour ; but in these cases the sun is, I believe, not seen at all, but 
we get strips of green sky, which are often seen. The atmosphere, then, I believe, 
contains at present a large amount of vapour existing actually as vapour, and not 
condensed into clouds ; hence even a great thickness of it is transparent, except to 
those particulp^r rays which aqueous vapour, absorbs. . 

" The green colour can be seen only at a particular altitude, for only there is 
the thickness sufficient to produce the necessary absorption. At higher altitudes the 
peculiar silvery white is exactly what we are to expect.'* 

Mr. Henry Cecil asks (^) whether the green sun, seen at about the same time in 
Southern India, Ceylon, and the West Indies, be due solely to the presence of aqueous 
vapour,- Is not the air- in these regions noimally surcharged through a considerable 
period of every year with aqueous vapour ? And yet this appearance is so unusual as 
to create alarm ! . Can, then, so rare a phenomenon be due solely to so general and 
common a cause ? When Lockyer saw his green sun through the steam on the 

2 F 2 



216 MR. E. DOUGLAS ARCHIBALD 

boat, were there not also, mingling with the vapour, sulphurous fumes from the 

funnel ? 

To this the Editor of * Nature ' appends the following : — 

** The sun l)as been seen green through mist on the Simplon,** 

Some account of experiments and observations bearing on the subject of blue or 
otherwise coloured suns will be found in the following papers : — 

(1.) "On the Colours of the Atmosphere" (by Professor Jahes D.Forbes, 

F.RSS. L. and E., Edinburgh, 1839), which includes reference to numerous 

antecedent papers on the same subject. 
(2.) '*Note sur un eflfet de Coloration des Nuages." Par M. J. Fournbt. 

1852. 
(3.) Two papers by M. Fournett In the ' Comptes Rendus,' vols. xlviL and xlviii., 

1858 and 1859, on "The EflFect of Aqueous Vapour in causing Blue 

Suns." 

In the first of these, Professor Forbes refers to experiments made by him on the 
peculiar orange colour transmitted by steam during a critical stage of its condensa- 
tion, and attributes the colours at simset to the presence of vapour in a partially 
condensed state. He only incidentally refers to the blue and green suns of 1831, 
which he agrees with M. Abago in considering as the effects of contrast with an 
intensely red sky. 

M. FouBNET found that the presence of water vapour imparted to the atmosphere 
a bluish or orange colour. The phenomenon is seen when the sun's light passes 
through a cumulus cloud which increases in thickness from the border to the centre. 
It appears most favourably when the sun is hidden by one cloud, and the borders of 
the neighbouring clouds appear golden or orange tinted. Between this orange -tin ted 
region and the sun's disc a bluish region intervenes, and if in this central region the 
Sim itself is seen through the cloud- veil with more or less distinct contour, it appears 
blue or pale white or orange.* 

M. Foubnet apparently attributes this blue colour solely to the effect of contrast 
with the red border. 

These observations leave it uncertain whether the phenomenon of a blue sun, 
as seen by M. Fournet, was a purely transmission effect or partly one of contrast 
with the red border ; in which latter case the blue space surrounding it might have 
been partly a real colour, due to diffraction. If the sun was really seen blue itself, 
both in these cases and in those after the Krakatoa eruption, the colour must have 
been due to transmission and not to diffraction. 

Finally, Dr. Kiessling, of Hamburg, has made experimentst to see in what 

• Professor Kiessling in *Met. Zeitschrift,* 1884, p. 119. 

t Described in the *Met. Zeitscbrift/ Marcb, April, 1884; 'Nature,' vol. xxxi. (1885), p. 439; and 
in bis pampblet entitled ' Die DammemrigserscbeinnTigen im Jabre 1883.' 



ON THE COLOURED APPEARANCES OF SUN AND MOON. 217 

circumstances a coloured sun could be produced. He finds water vapour alone, in 
dustless air, ineffective. Water vapour in ordinary dusty air, and under conditions 
which gave rise to a foggy condensation, produced transmission tints varying from 
brownish-red to grey -blue ; but he could not, apparently, produce the green tint 
artificially (probably because the yellow transmissions through the ordinary lower 
atmosphere were not present in these laboratory experiments). 

All thb leads to the conclusions which may be summarized as follows : — 

Summary op Part IV., Section I. (c). 

(1.) That the appearances of blue, green, sOvery, and coppery sun, seen mainly 
in the tropical zone after the eruption of Krakatoa on August 27th, and sporadically 
after its predecessor in May, 1883, were produced by the action of a haze which 
proceeded from the neighbourhood of the volcano, and was composed either of dust 
and vapours mixed, or of dust alone, probably the former at first. 

(2.) That the silvery ot pale sun was seen where the haze was most dense near 
the parallel through Krakatoa. 

(3.) That the coppdry sun was seen either near the Equator, or where a narrow 
shoot of the stream occurred towards Japan, and near the eruption, as at Teloek 
Betoeng, from which it may be inferred to have been caused by dense, and perhaps 
coarse, dust from the eruption, mingled with lower atmospheric absorbing agents. 

(4.) That the blue and green suns were seen further from the latitude of Krakatoa 
and the Equator, where the stratum was more attenuated. 

(5,) That where the sun was seen blue near the zenith, it frequently became 
green or yellow on approaching the horizon, and vice versd, and that these changes of 
tint were due to changes in the thickness of the medium and of the lower atmosphere 
traversed. 

(6.) That similar appearances have been witnessed on former occasions {see 
Section V., p. 384), in association with accompanying volcanic phenomena, and in 
regions where the air was, during the time, charged with terrestrial dust. 

(7.) That Professor Kiessling, of Hamburg, has experimentally obtained a blue 
sun (1) with a cloud of chloride of ammonium, and (2) with aqueous vapour mixed 
with ordinary dusty air.* 

(8.) That while in the tropical zone the coloured suns occurred for the first 
month after the eruption co-extensively with the other optical eflfects, the sun and 
moon were only occasionally and temporarily seen green at a few places in the extra- 
tropics ; and in some of these it is not certain that the appearances were due to 
anything more than contrast colours. 

E, Douglas Archibald. 

• Professor Kiessling kindly sliowed these experiments to tlie writer when visiting Hamburg in 
August, 1887. 



218 MR. E. DOUGLAS ARCHIBALD 



References in Section I. (c). 

Q) * Taglicbe Rundschau,' 1883, Nob. 255 and 256, and a communication to M. Verbeek by M. 
Herring, at Batavia. 

(») * Mercantile Record/ June 16, 1883. 

O 'Nature,* vol. xxix. (1883), p. 196. 

(*) Colonel J. Stoddart, Report, MSS., April 10, 1884 {ante, p. 116). 

(») * Gold Coast Times,' September 14, 1883. 

(•) * Nature,' vol. xxix. (1884), p. 252. From a Dutch paper. E. Metzger. 

(') * Panama Star and Herald,' * Nature,' vol. xxix. (1883), p. 152. Hyde (JUrk. 

(«) Letter of Hon. Foley C. P. Vereker, of H.M.S. Magpie, dated Labnan Island, October 1, 1883, 

(») * Hausa,' January 2, 1884. 

(i«) ' Ceylon Observer,' November 9, 1883. 

(") Letter from Miss Cathcart, September 8, 1883. 

(") 'Nature,' vol. xxix. (1883), p. 7. 

(») M. A. T., 'Madras Mail,' 'Nature,' vol. xxviii. (1883), p. 577. 

(**) C. Michie Smith, * Nature,' vol. xxx. (1884), p. 348. 

(") C. Piazzi Smyth, * Nature,' vol. xxviii. (1883), p. 576. 

(") 'Quarterly Journal Royal Met. Society,' vol. x. (1884) p. 153. 

(") 'Nature,' vol. xxx. (1884), p. 347. 

(") ' Nature,' vol. xxviii. (1883), p. 576. 

('•) * Ceylon Observer,' September 17, 1883. 

(») 'Knowledge,' March 14, 1848. 

(*») 'Nature,' vol. xxix. (1883), p. 177. 

(«) 'Nature,' vol. xxix. (1883), p. 199. 

(^) ' Knowledge,' March 14, 1884. 

(•*) 'Nature,' vol. xxviii. (1883), p. 575, and 'Times,' December 8. 

C) 'Englishman's Overland Mail,' September 23, 1883. 

(«) ' Nature,' vol. xxviii. (1883), p. 612. 

(•) ' Met. Zeitschrift,' February, 1884, pp. 49-65. 

(^) M. E. Marence, in ' L' Astronomic,' by C. Flammarion. 

(«) J. Norman Lockyer, F.R.S., * Times,' December 8th, 1883. 

(*) 'Nature,' vol. xxix. (1884), p. 549. 

(•) Beuf, ' Comptes Rendus,' vol. xcviii., pp. 498, 549. 

(') Ship's log, preserved in the Meteorological Office, London. 

(«) " The Equatorial Smoke Stream," * Hawaiian Monthly.' By S. B. Bishop. May, 1884. 

(»») ' Ceylon Observer,' November 2, 1883. 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 219 

PART IV., SECTION I. (d). 

The ''Sky-Haze" and some of its Effects. 
By Mr. E. Douglas Archibald. 

Nearly all the observers of the twilight glows, coloured suns, corona, &c., agree 
in attributing them proximately to the physical action of a peculiar and quite 
abnormal cirri-form haze which appeared concurrently, and at a great altitude, at first 
in the Indian Ocean, whence it spread round the Equator, and ultimately towards 
the poles. 

It is especially important to notice its earliest appearance, which, like those of 
the other phenomena, seems to have occurred shortly after the minor eruptions of 
Krakatoa in May, 1883. 

Thus on May 26th, from the log o^ Her Majesty, (^)* lat. 3° 8' S., long. 90^ E., at 
9 p.m., we hear of a " thin haze over the sky through which the larger stars shine.'*' 

By itself this latter observation might not be thought to refer indubitably to 
kaze similar to that which appeared after August, but when it is compared with the 
descriptions of the latter, and the " blue moon seen through light haze" on the Belfast y 
on July 16th and 1 7th, (^) referred to in Section I. (e), we can hardly doubt that 
it was a similar manifestation. 

After this, the next notice we have of the haze was from the ship Charles 
Baly on August 22nd, after a minor eruption of Bjrakatoa, in which it reports, in 
15° 30' S., lOS** E. (not very far from the volcano):—" In the E. and N.K there was a 
strong white haze or silvery glare." (^) The words "silvery glare " are several times 
used subsequently by other observers. 

On August the 27th, the day of the grand eruption, the Barharossa, in 2% S., 
62*°9 K, after mentioning the unusual silvery sunset on that day, reports : — " The 
sky was covered during the night and Ukewise hazy, although we had no signs 
ofdew."C) 

On the same day we have the observation on ])oard the Sea Witch, when ashore 
on the bar of Sourabaya, Java, of the sun " appearing dim and smoky, while sounds of 
heavy cannonading were heard, and the barometer was unsteady." (*) 

On the same day the Simla, 5° 35' S., 88° K, reports :— " Air very hazy." (^) 

On the same day (27th) Dr. Mbldrum (^) says that the sun was obscured at 
Kodriguez and the Seychelles, the sky at the latter being reported by Mr. Estridgb 
to be hazy all day, and followed by a gorgeous sunset. At the St. Brandon Rocks 
" the sky at sunset had a peculiar smoky appearance, which extended nearly to the 
zenith in an E.S.E. direction." At Diego Garcia, from August 27th to 31st, the suu 

• For numbered and lettered references in this Section, see p. 230. 



220 MR. E. DOUGLAS ARCHIBALD 

was obscured during the day ; while at sunset a deep purplish-red glow appeared 
until 7.15 p.m. At Mauritius, on the 27th, the sky was overcast during the day and 
the sunset was smoky in the west ; and on the 28th the sunset was gorgeous. On 
the 28th the ship Charlotte, r^'S S., 106-°2 K, reports, "hazy air,"(») and Captain 
LoYSEAU of the Salazic, lat. 9° 15' S., long. 93° E., talks of encountering blinding 
showers of sand, while the sun was reddish and the sky white C) 

On August 28 th the haze continued at Diego Garcia, Rodriguez, the Seychelles, 
and Mauritius, and was observed by the Simla, 6** 12' S., 88° 17' K, "At 2 p.m., 
sky very hazy, a fine white powder falling in a constant shower like snow. At 
8 p.m., sky still very hazy and dust falling." (^) 

On August 29th the Simla, 6"" 26' S., 87"" 52' E., reports:— "A very large 
quantity of dust fell in the past night. Very hazy still, and dust falling. At 5 p.m., 
sun completely obscured 15° above the horizon, owing to haze ;" and at 8 p.m., " still 
dust." (^) On the same day, the Coppename, 15° 30' N., 57° 30' W., says :— 
" Clouds appear dry, smoky, and indescribable, at 8 p.m. At 4 p.m., hot looking 
stratus in N.W. ; " (^) and from August 28th to 30th the Ida, in l-°3 N., 108-°4 K, 
not far from Java, reports : — " Uninterruptedly hazy air.'' (•) The British Empire 
2° 37' S., 79° 52' E., also remarks : — "A pale yellowish haze accompanying a fall of 
dust like Portland cement." (*) 

On August 30th and 31st, we have the observation at Tokio, Japan, referred to 
elsewhere, of a " yellowish-grey haze." And on the latter date the observations on 
board the Corona, 1° 20' S., 21° W., " at 8 a.m. a metallic sort of haze over sky, sim 
shining through it quite coppery ;" and on board the Olbers, in 3° 5' N., 27° W., of 
** light clouds visible towards sundown " (very similarly worded to the description of 
the haze subsequently in the extra-tropics). 

On September 1st, the Queen of Cambria, in 9° S., 28° W., at 8 a.m., notices "a 
peculiar thin haze in the air, through which the sun is seen with a clearly defined 
circumference, and almost white in colour ; at 8 p.m., stars dimly visible through 
haze.'' (^) 

On September 2nd, the Olbers, 4° 41' S., 31° 10' W., again reports :—" The 
sun obscured at intervals. At 5 p.m., the sim visible through clouds, pale 
blue." t^) 

On the same day we hear of "a long belt of vaporous sky" at Medellin, 
in connection with the coloured suns and glows in that part of South America, and 
a pecidiar grey sky through which the sun shone faintly was seen by the 
Frieda Grampp, 10°-2 S., 27°'2 W. ; the Rosario, 3°-7 N. ; and the Argentina, 
12-°1 S., 36°'9 W. (•) 

On September 3rd, the Queen of Camhna, 3° 6' S., 27° 4' W., reports :— **Before 
sunrise the haze that is still in the air was fiery red, and the sun, when it appeared, 
was of a dazzling white colour." (^) 

On the same day the Scotia, 1° 37' N., 71° E., reports " hazy overhead ; " and on 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 221 

September 6th the same ship, 5° 52' N., 58° 55' E., reports " very fine sand deposited 
in places exposed to the wind." (^) 

On September 3rd, the Euterpe^ 14° S., 7°'9 W., reports : — " During the last few 
days there is above the cumulus and stratus clouds a uniform grey cloud mass which 
frequently covers the entire sky." (*) A similar stratum was observed by the 
Argentina, in 8°-2 S., 34°-6 W. («) 

From September 1st to 5th we have the observation, referred to in Section I. (k), 
of the "sun being surrounded by a delicate atmospheric film, through which the 
sun could scarcely shed its hght," C^) 

On September 4th and 5th a similar appearance was noticed by the Euterpe 
and Argentina, and by the Papa, in 10° 19^ N., 161° 21' W., which reports :— "The 
sky in the morning is covered with a thin white layer. The sim comes through. The 
air looks yellow and watery." (•) 

On September 6th, Eastern time, the same ship, in 8° l' N., 161° 4' W., remarks : — 
" The entire sky is covered by an even yellowish-red, high layer of cirro-stratus. 
The sun pierces through, but looks pale, as when seen through a blue glass, 
with sharply marked edge, nice for observations, well tolerable to the eye, without 
nimbus or halo. At night the stars were dimly visible." (•) 

Thenceforward we have with Uttle intermission, accounts worded in very similai' 
language, of the sky being " covered with a light haze ; " (®) " the sun, when 
green, stands out from a smoky sky," S"" to 16° N., 87° 30' to 88° 44' E. (®) 
Together with the accompanying phenomena of the blue and green suns, it 
appeared after the first revolution of these round the globe, at higher latitudes 
than on its first journey. Thus, while on August 27th, at Mullaittivu and Kokkulai, 
in Ceylon, the sky was " murky, and the rays of the sun obscured to the 
east," i}^) it does not appear to have been generally observed in Ceylon, or to 
have reached Madras and other places north, such as Ongole, until its return on 
September 9 th.* 

At Ongole, on September 10th, 11th, and 12th, "the sun was blue, green, 
and yellow. After sunset a peculiar haze covered the sky. It was not of 
suflScient density to be at all visible except where it reflected the direct rays 
of the sun. Then it had a singular mottled appearance, with a smoky look 
along the denser portions, suggesting clouds of smoke or dust in the upper atmos- 
phere." (11) 

Again, on September Xlth, at Pallai, Ceylon, we hear that " the last day or two 
have proved very hazy, and the sun shines with a bluish tinge. I followed the large 
spot on the sun this afternoon without even the aid of smoked glass, the sun's 

=* From this observation it appears that the northern edge of the dnst-stream from Krakatoa, just 
skirted the northern edge of Ceylon when starting on its first revolation. Krakatoa being in 6° south, 
would make the semi-width of the stream 14°. 

2 G 



2'^2 MR. B. DOUGLAS ARCHIBALD 

brightness being so dimmed by the dense masses of blue haze in which he eventually 
disappeared." (^^) 

A communication from an observer in 10° 48' N., 78° 52' E., September 10th, 
states that " The sun was shining with a subdued light in a distant and hazy, but 
otherwise cloudless, sky. It could be looked at steadily with the naked eye. The 
appearance was decidedly as if the ordinary sun was screened off by a thick stratum 
of vapour which cut off some of the component rays of white light and made it look 
green." (») 

At Poudicherry, September 12th, ** This is the third time the sun has been 
dimmed. It is as if it were covered with a thin gauze veil of tender Prussian 
blue." (A*) 

It also seems to have lasted in these places for some considerable time. Thus, 
Mr. Parker, at Hambantota, Ceylon, says, October 11th : — "There is still haziness 
night and morning. In the morning for about an hour and a half after sunrise, and 
in the evening for a similar length of time." (*^) 

The same stratum afterwards spread over extra-tropical regions, and was 
chiefly observed by Messrs. Russell, Perry, Bozward, and Glydk, in England, 
and MM. Krone, Thollon, Ricjcd, Janbsch, Pockels, and Lecher, on the Con- 
tinent. 

The Hon. Rollo Russell, who observed the phenomenon very closely, thus 
describes its second appearance near London on November 9th : — " There was a 
slight haze on the horizon at sunset, having a greenish-white and yellowish-white 
opalescence at its upper border. About 15 minutes after sunset the sky was pink, 
and below the pink a shining green and white opalescence, like a luminous mist. 
The coloured portion of the sky was fan -shaped and resembled a very high thin 
filmy cirrus. . . . The illuminated portion seemed not to belong to clouds 
but to glow of itself, like some super-atmospheric film; and yet the idea of 
an extra atmospheric cause could not be entertained consistently with its later 
behaviour." ('*) 

Herr Pockels, in Brunswick, writing December 31st, states that after the glows 
of November 27th, 28th, and 29th, **The almost cloudless sky was covered with 
exceedingly filmy, wavy, and woolly clouds, which could be seen only near the 
sun." 07) 

Mr. Glyde (Torquay) speaks of it as " a greyish mist, but tinted pink near 
the sun, and covering the sky all day. It was higher than the most elevated 
cirrus." {^^) 

Professor O. N. Stoddard (Wooster, Ohio) says that it is "not an ordinary 
cirrus-cloud." (^®) 

Prof. Hazen, in Washington, speaks of the sun, in an otherwise cloudless 
sky, " as shining through a dense haze ; " a similar haze being seen round the 
moon. (^^) 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 223 

Rev. S. J. Perry, F.R.S. (Stonyhurst), says that the haze " bore no resemblance 
to ordinary haze/* (^^) 

M. Thollon observed the same haze at Nice from November, 1883, onwards, 
and attributed to it the coronas round the siin and moon, as well as the lack of 
definition in astronomical observation. (^^) 

Professor A. Ricc6, of Palermo, speaks to the same eflTect, and describes the 
haze as being "minutely and irregularly channelled, as if composed of cirro- 
strati." n 

M. C. MousELLE, of Auteuil, photographed the vicinity of the sun in 1884, and 
says : — "These photographs show a corona of diffused hght about it, the intensity of 
which depends in part on the degree of transparency of the very filmy clouds, having 
a hazy or stratified appearance, and which seemed to be the sole or principal cause of 
the corona." 

The similarity of the foregoing to the remarks of observers within the tropical 
zone is suflficiently obvious, and raay be further corroborated by a perusal of the Table 
of First Appearances in Section II., p. 263. 

Peculiar Features of the Haze. 

(1.) There seems to have been a difference in the quality of the haze as it was 
first seen near the Equator, and more especially in the Indian Ocean, and as it after- 
wards appeared in higher latitudes. 

Thus, in the former regions the haze seems to have been yellow, reddish, smoky, 
or white, to have covered the entire sky, and to have been visible at midday, 
and it is only in these regions that it appears to have been thick enough 
to cut off some of the component colours of the spectrum, and produce blue and 
green suns at high altitudes. In these regions it was also dense enough to hide the 
sun entirely when the latter was within a few degrees of the horizon. 

On the other hand, in higher latitudes it appears to have been generally thinner, 
only partially visible and more like a gauzy cirro-stratus. 

Thus Professor Stoddard, in Ohio, says : — " It was invisible everywhere except 
near the sun ; " and Mr. N. S. Shaler * speaks to a similar effect. 

Mr. Bishop says : — " Even at Honolulu it was always perfectly transparent and 
invisible except under certain conditions." 

The Hon. Rollo Russell says : — " It is visible (except when very dense or in 
the neighbourhood of the sun) only about the time of sunrise and sunset. During the 
day not the faintest trace obscures the clear azure, whereas ciiTus becomes more 
distinct with more daylight." (^) 

In England, then, the haze was probably too thin to produce coloured suns, but 

* * AtlanUc Monthlj/ April, 1884. 
2 G 2 



224 MR. E. DOUGLAS ARCHIBALD 

thick enough to be seen and to cause a glow by reflection, when the solar rays fell 
upon it at a small incident angle. 

It is scarcely necessary to remark that the thinning off of the haze in the extra- 
tropics is exactly what might have been expected if it had its source near the 
Equator, while the march westward, conciurently with the other optical effects, which 
it cannot be doubted were proximately due to it, leads us back to the Indian Ocean 
as the source, and August 27th as the dat«, of its first appearance in any great 
quantity. 

(2.) It had generally a rippled or striated structure, somewhat analogous to cirrus 
or cirro-stratus. 

Several observers testify to this, including Messrs. Perry, Bishop, Rioo6, Sealer, 
Russell, Rebeur-Pasohwitz, Bozward, Krone, and G.A.N. ("), and it seems to 
have been noticed from the very first. Thus, in 3°'2 S., 16°"4 W., the s.s. Carola 
notes that " the atmosphere appeared to be full of very small uniformly distributed 
clouds." (•) 

The Rev. S. E. Bishop talks of " a wavy ripple " observable in its structure. 

Mr. Shaler, in the 'Atlantic Monthly,' remarks that the haze is "stratified;" 
and Dr. Rebeur-Paschwitz, on December 18 th, notices "strise dipping at different 
angles." {'') 

The Hon. Rollo Russell, who carefully observed the haze very closely in 
Surrey, says that it was more analogous to cirro-stratus than cirrus, but to cirro- 
stratus seen at a distance, for cirro-stratus seen overhead presents features not seen in 
the cloud-haze. In fact, none of the icsiuil characteristics of the highest clouds were 
apparent in the earlier phenomena of November and December, 1883. The haze 
usually resembled simply a haze or smoke, in bands of greater and less density, 
without Jibres or angles, but later on, some cross striations became visible in the 
bright part of the sky after sunset, and these closely resembled the striated cirro- 
stratus. At a distance, i.e., when seen on the horizon, the resemblance to cirro- 
stratus seems to have existed fi'om the first in the tropics. The total absence of 
cirrus forms, such as mares' tails, is remarkable. 

Again, he observes : — " It showed the sort of stratification in thin streaks, which 
often appears in cirro-stratus, but its elevation was evidently greater than that 
common to this cloud." (**) 

This stratification was not constant, and on some days the structure was 
amorphous. 

Messrs. Russell, Shaler, and Bozward testify to a motion being observable 
in the streaks, though they differ widely in their estimates of such motion, 
the two latter making the streaks move rapidly in a north-east direction, while the 
former only once or twice observed an apparent and very slow movement eastwards 
after long watching on several occasions. 

Accoixiing to the Hon. Rollo Russell, the direction or axes of the streaks 



ON THE SKT-HAZE AND SOME OF ITS EFFECTS. 225 

generally lay south-west to north-east, both in England and in Italy. Professor 
Ricc6 confirms this,* as well as the indications of a motion in the same direction. 

(3.) Its presence peculiarly afiected astronomical definition. 

On this point we have pretty general testimony, including that of Messrs. 
Saxby r), F.RA.S. (^), W. C. WiNLOCK,t Krone, Piazzi Smyth, &c. 

Mr. Saxby says : — "An auroral haze of similar appearance to the red sunset haze 
will often improve the definition of celestial objects, but this haze shows a decidedly 
opposite tendency ; and a Herculis was so blurred as to be scarcely recognisable at 
altitudes at which any ordinary haze would have transmitted a tolerable result." 

It was found, by the party deputed by the Royal Society to photogi'aph the 
solar corona on the Riffel, under the charge of Mr. C. Ray Woods, that the year 
1884 was exceptionally unfavourable for the work, "in consequence of an unusual 
want of transparency in the higher regions of the atmosphere, this made it impossible 
for Dr. HuGGiNS to obtain any photographs of the corona that year in England."(^) 

Mr. John Ballot, in the Transvaal, noticed on the 7th April, 1884, that "the 
sky seemed clear and the stars bright, but on using the 6-inch on Jupiter, the planet 
presented most of the time just a luminous blurr with spurious images flapping on its 
sides, which seemed to me to be caused by the glow-producing medium.*' (*^) 

Dr. Krone noticed that at midnight the haze obscured all stars below the 4th 
or 5th magnitude (*^), and 

Mr. WiNLOCK reports : — ** Stars of the 3rd or 4th magnitude, which have 
frequently been seen on a good observing day, it is almost useless to try for now, the 
phenomenon is evidently not local." 

(4.) The peculiar efiects witnessed during subsequent lunar eclipses. 

There have been since September, 1883, only two total eclipses of the moon, and 
there was one large (0*88 of moon's diameter) partial one. 

Of the first, April 9th, 1 8 8 4, no record has been found. The second, that of October 
4th, 1884, attracted considerable attention from the abnormal obscurity of the moon. 
The facts are given at large in several papers in the * Monthly Notices ' of the Royal 
Astronomical Society, but the following extracts sufficiently indicate its exceptional 
character : — 

Total Eclipse of the Moon, October ith, 1884. 

Bodcliffe Obs., Oxford.— M.r. E. J. Stone, M.A., F.R.S., saysj:— "The eclipse 
was much the darkest that I have ever seen." 

Dun JEcht. — Mr. J. G. Lohse says : — " During the totality the moon was very 
faint, and the copper tint, so conspicuous in other eclipses, was seen only occasionally, 
and then only faintly." 

* In his paper quoted in Sections I. (b) and I. (e). 

t " The Long-continued bad Seeing," * Science,' vol. iv., 1884, pp. 94, 96. 

X * Monthly Notices,' vol. xlv., p. 34. 



226 MR. E. DOUGLAS ABC^HIBiLLD 

Stonyhurgt. — The Rev. S. J. Pkrey, F.R.S , says : — '' The usual copper tint of the 
eclipsed moon was not perceived except towards the close of the eclipse, and then it 
was only very slight." ^ 

Bristol.— Kt. W. F. DsNNrNO says : — *' The most noteworthy feature in con- 
nection with the phenomenon was that the moon at the total phase appeared far 
less luminous than usual." . . . . '^ The firmam^it grew dark as on an ordinary 
night when the moon is entirely absent." 

Bridpoi'L — The Rev. S. J. Johnson says : — ** At 9 h. 10 min., the whole of the 
lunar circle began to be seen through the telescope, but without a trace of the 
ordinary coppery redness — to quote Keplbb, respecting the lunar eclipse of June, 
1620 — ^wie omni nibedine."* 

Clapham, London. — Mr. Edmund J. Spitta* says : — " During totality the moon 
was, generally speaking, exceedingly faint — indeed, at times barely visible to the 
naked eye — and presented none of the coppery colour usual on those occasions." 

The only other subsequent lunar eclipse of importance, that of March 30th, 
1885, was not visible in this country, but was observed in Tasmania by Mr. A. B. 
BiGGS.(^') He says that, at the time of maximum eclipse, "All within the shadow 
was utterly obliterated — ^lost in the dead slaty tint of the sky. I could not 
distinguish a single crater after once it was fairly within the shadow. Not the 
^lightest trace of the coppery tint was visible throughout." 

This peculiar absence of the coppery tint ordinarily visible, and m circumstances 
which are described as having been very favourable for observation, " the sky being 
free from clouds, and the moon in full view during the whole period of the eclipse," 
seems to favour the notion that the haze not only exerted a general absorption, but, 
as the appearance of the blue and green suns show, a selective absorption, more 
especially of the red end of the spectrunut 

(5.) The radiant point of the wisps or streaks of the haze when the glows were 
at their best, and the structure of the haze when noticeable, lay apparently some 
distance below the horizon. 

This was particularly observed by the Hon. Kollo Russell. 

(6.) Though somewhat analogous to cirrus, the streaks of haze never presented 
a curled or twisted appearance, but were, apparently^ long parallel bands. 

• * Montlilj Notices, Boy. Aat. Soc.,' vol. xlv., p. 154. 

t [Since this was in type an article by Professor Dufoue has appeared in Flammaeiok's 
* rAstronomie ' (January, 1888), in which he strongly supports the theory that the almost complete 
invisibility of the moon in 18d4> was due to Krakatoa dnst, and he refers to M. Flahmariok ha\ring 
expressed the same view. On turning to M. Flammabion's original statement (* TAstronomie,* 1884, 
p. 407), it will be found that he refers to the eclipses of April 25, 1642, May 18, 1761, and June 10, 1816, 
as previous analogous cases. On comparing these and that of 1620, observed by Kepler, with Part lY., 
Sec. v., of this volume, it will be found that in each of these four instances there had been an eruption 
in the previous year — that of 1815 being the great one of Tomboro. — Eo.] 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 227 

This was generally observed, and appears to indicate that the haze was at too 
great an elevation to be affected by the vertical, or other movements, which accom- 
pany cyclonic and anti-cyclonic systems at lower altitudes. 

(7.) At sunset the haze began to shine with a red light soon after the cirrus had 
ceased to shine ; about 20 minutes according to the Hon. Ex)LLO Russell, 

(8.) It had a definite lower boundary. (Aitken.)* 

This also was noticed by Mr, BiSHOP.f 



Sbculab Dubation. 



The cloud-haze not being so conspicuous as some of the other phenomena, 
except near its origin within the tropical belt, has not been so closely observed. 
At first it was seen generally throughout the tropics in connection with the coloured 
suns, corona, and twilight glows, and subsequently with the two latter in the tem- 
perate zones. In the former region it was distinctly noticeable, apart from the 
attendant optical phenomena. In the latter, it was noticed at first only near 
sunrise and sunset in connection with the twilight glows ; but subsequently it 
was noticed more generally in* connection with the corona surrounding the sun 
in the daytime. 

The Hon. Eollq Eussell, at Richmond, Surrey, when observing the glows, and 
writing on January 22nd, 1884, says; — "It has been visible on every clear day for 
more than two months, and has been quite independent of wind and weather." 

The same observer, when in Italy between January 3rd and 4th, says : — " The 
intensity or thickness of the reflecting stratum was certainly much less than at the 
end of November." Further on he says : — "In the glows of December, 1883, and 
January, 1384, the m^-tter concerned seemed to become thinner." 

The Rev. S, E. Bishop, writing from Honolulu in April, 1884, says: — "The 
haze, with its glows and opslescenfc corona round the sun, is still being constantly 
seen." {«) 

After this we do not hear much of the haze independeniily of the other 
phenomena, though it certainly continued to be seen whenever the conditions were 
favourable for a twilight glow, while its prolonged presence is attested by various 
observations — ^spectroscopic, astronomical, and polariscopic. 

Like the corona, it survived in a modified form the more brilliant phases of 
tlie twilight glows ; and, like it, appears to have become almost imperceptible towards 
the close of 1885. 

* Second note on remarkable sunsets, * Proc. Royal Soc. Edin./ 1883-84. 
t * American Met. Journal,' August, 1886, p. 129. 



228 MR. E. DOUGLAS ARCHIBALD 



The Connection of the Sky-Haze with the Erufhon of Krakatoa, 

The remarkable haze which we have juBt described, and to the peculiar physical 
properties of which the other optical effects are attributed, both by those who only 
casually observed them and by those who subjected them to a more prolonged 
scrutiny and analysis, appears to have been nothing more or less than the smoke 
(so-called) of the eruption, attenuated into a semi-transparent film. 

It appears to have been manifested sporadically after the May eruption, as well 
as generally after that in August, the observation on Her Majesty on May 26th, 1883, 
in 3° 8' S., 90° E., at 9 p.m., of " a thin haze over sky through which larger stars 
shine/' being worded very similarly to those which were noted afterwards in such 
abundance. 

In many oases in the Indian Ocean it was reported simultaneously with falls 
of dust on ships ; and in most cases wherever it appeared, especially in the 
Indian Ocean, it was accompanied by coloured or silvery suns and by glows at 
twilight. 

On the other hand, there are few detailed accounts in which, where glows, &c., 
appeared, either haze or a lofty cirro-stratus, or a delicate atmospheric semi-trans- 
parent film, or a " peculiar," " smoky," and " indescribable *' cloud-stratum is not 
mentioned as a concomitant. 

For the first two or three days after the eruption which ended on August 27th, 
it appeared over the groups of islands in the south-west part of the Indian Ocean, 
represented by Diego Garcia, the Seychelles, St. Brandon, Rodriguez, and Mauritius, 
and by the ships Barbarossa, Simla, Charlotte, Salazic, British Empire, Scotia, and 
Ida — the former representing an area embracing 20^ of longitude and 20^ of latitude, 
and the latter a different one covering 29^ of longitude by 14® of latitude, and 
between them the larger part of the Indian Ocean. Later on we hear of its being 
observed, like the other phenomena, not only over widely distant localities along the 
equatorial belt, but for days together through considerable ranges of latitude by the 
Queen of Cambria and Olbers in the Atlantic, and the Papa in the Pacific, showing 
it to have been of fairly uniform extension, as well as of general occurrence. 

The remarks on board the Corona on August 31st, and Queen of Cambria on 
September 1st, in particular, are clear in showing its appearance in the Atlantic area 
soon after its general spread over the tropical part of the Indian Ocean, to have been 
of a precisely similar character to that observed in the latter ocean, and the following 
observation on the latter ship on September 13th, in 14° N., 26° 42' W., accentuates 
this general uniformity as well as peculiarity of appearance : — " I don't know what 
to call the stuff that is seen in the upper regions, thin cirro-stratus or haze ; it 
was like that seen south of the Equator, first early on September 1st and last on 
September 5th." 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 229 

That the haze was the proximate cause of all the other optical phenomena is 
amply testified to, both by the direct statements of observers, some of which we have 
quoted in the present section, and also by numerous cases in which its presence is 
indirectly associated with that of several of the other phenomena. 

This fact being once established, forms one of the strongest arguments in favour 
of the dependence of all the optical phenomena, following both the minor and the 
major eruptions of Ejrakatoa, upon the finer material ejected during those outbursts. 
Moreover it is plain fi-om the earlier records, some of which are quoted in Section II., 
p. 264, that the haze began close to where the thick voliunes of smoke, seen near 
the volcano, ended. 

Mr. Elleby, F.R.S., of Melbourne, and one or two other writers, suggest that the 
haze itself may have been a secondary chemical or physical effect of the eruption ; 
but there does not seem to be any evidence to show that the intrusion of volcanic 
ejectamenta into the atmosphere would introduce notable chemical changes into its 
composition, or that these would extend over a wider area than that embraced 
by the ejectamenta themselves. 

Summary of Part IV., Section I. (d). 

The preceding paragraphs present an outline of the chief facts in connection with 
the cloud-haze, and lead to the following conclusions : — 

(1.) That soon after the grand eruptions of Krakatoa on August 26th and 27th, 
a remarkable dimming of the sun took place in the immediate neighbourhood of the 
volcano, together with haze and fctlls of dust on ships, which in one case (the Scotia, 
September 8th, in lat. lO"" N., long. 53° E., " still a deposit of sand found ") extended 
no less than 62° to the westward, and more than 3,700 English miles from the volcano. 

(2.) That this haze was propagated mainly westwards, concurrently with the 
other optical phenomena, from the neighbourhood of Java. (In Section III. (c), p. 337, 
the exact rate of transmission is worked out.) 

(3.) That most observers agree in considering it to be the proximate cause of 
the other optical effects, including the twilight glows, coloured suns, and large 
corona. 

(4.) That it was densest in the Indian Ocean and along the equatorial belt, where 
it was often thick enough to hide the sun entirely when within a few degrees of the 
horizon, besides sensibly colouring its rays when at greater altitudes. In the extra* 
tropics it was much less dense, and was generally visible only at sunrise and sunset ; 
though even there it peculiarly affected astronomical definition in a manner different 
from ordinary aqueous haze. 

(5.) That while, in some of its features, it partook somewhat of the character of 
a lofty cirrus or cirro-stratus cloud, it yet differed in many respects from an ordinary 
aqueous cirrus. 

2 H 



230 MB. B. DOUGLAS ARCHIBALD 

(6,) That it appeared to be far above ordinary cirri, and exhibited an absence of 
the curls and twists by which such clouds are usually characterised, and which are 
usually attributed to local atmospheric movements at their level. (Its height being 
that deduced in Section IV., p. 340.) 

(7.) That while it was at a height where the temperature is always far below the 
freezing point of water, no trace of true ice-halos was observed, and that while it 
produced some effects, such as coloured suns and glows, which might, in certain cir- 
cumstances, have been caused by aqueous vapour, the general evidence shows that it 
contained something besides ordinary aqueous vapour, and that it was either entirely 
fine dust or a mixture of frozen vapour of water or other substances with dust. 

(8.) That the spectroscopic evidence referred to in Sections I. (c), p. 199, and 
I. (e), p. 231, tends to show that the haze was not gas, but a cloud of solid particles, 
either ice or dust, which at first cut off the red end of the spectrum relatively more 
than the violet, and subsequently exercised a general absorption, which was more 
noticeable in the less intense rays at each end, than towards the middla 

(9.) That it appeared on former occasions (1783 and 1831) in association with 
pale suns and twilight glows, which were at that time ascribed to contemporaneous 
eruptions. 

E. DouQLAS Abchibald. 



ON THE SKY-HAZE AND SOME OF ITS EFFECTS. 231 



References in Section I. (d). 

(*) All obserYations referred to thns are taken from Dr. Nemnajer's article in tlie 'Met. 

Zeitschrift,' February, 1884. 

C) All obseryations referred to thus are from ships* logs preserved in the London Meteorological 
Office. 

O ' Ceylon Observer,' October 12, 1883. 

O * American Journal of Meteorology,' vol. i., May, 1884. 

C) 'Proc. Roy. Met. Soc., Mauritius,' May 22, 1884. 

C*) * Comptes Rendus,' vol. xovii. (1883), p. 1101. 

C) ' Ceylon Observer,' October 2, 1883, 

C) * Japan Gazette,' September 21, 1883. 

O 'Nature,' vol. xxix. (1884), p. 366. 

O * L'Astronomie,' Flammarion, February 1, 1884. 

C) * Honolulu Advertiser.' 

(•) * Indian Daily News,' September, 1883. 

O Colonel J. Stoddart, MSS. BepoH, April 10, 1884. (See p. 116 et seq.) 

(") ' Nature,' vol. xxviii. (1883), p. 576. 

(») ' Ceylon Observer,' September 15, 1883. 

C*) * Ceylon Observer,' October 26, 1883. 

C*) • Ceylon Observer,' September 21, 1883. 

(^) H. Parker. MSS. Letter dated Hambantota, November 18, 1883. 

(") ' Quarterly Journal, Royal Met. Society,' vol. x. (1884), p. 139. 

(") • Met. Zeitsohrift,' March, April, 1884. 

CO ' Standard,' December 26, 1883. 

C*) ' Nature,' vol. xxix. (1884), p. 356. 

(*) * American Journal of Science,' vol. xxviii., March, 1884. 

(^) MSS., dated Stonyhurst, March 6, 1884. 

(») < Comptes Rendus,' vol. xoviii., p. 760. 

C") • Comptes Rendus,' vol. xcviii. (1884), p. 1299. 

(»*) ' Quarterly Journal Royal Met. Society,' voL x. (1884), p. 139. 

C*) ' Science,' vol. iii. (1884), p. 4. 

C^) ' Met. Zeitsohrift,' March, April, 1884. 

(") * Observatory,' vol. vii., p. 19. 

("•) • English Mechanic,' June 20, 1884. 

(«•) ' AthensBum,' May 9, 1885, p. 602. 

C') * English Mechanic,' May 29, 1884. 

(") * Launceston Examiner,' Tasmania, April 1, 1885. 

(») *Met. Zeitsohrift,' July, 1884. 

(^ ' Hawaiian Monthly,' May, 1884. 



2 h2 



232 MR. E. DOUGLAS ARCHIBALD 

PART IV., SECTION I. (b). 

The large Corona round the Sun and Moon in 1883-4-5, generally known 

AS ''Bishop's Ring." 

By Mr. E. Douglas Archibald. 

With the possible exceptioQ of some observations on board the Belfast, between 
16^ 31' S., 31° 40' W., and 11° 3' N., and 85° 53' E., from May 26th to July 17th, 1883, 
the first indications of this phenomenon were observed immediately after the great 
eruption of Krakatoa in August, 1883, and it continued visible until the spring of 1886. 

After the grand eruption, on the 27th of August, 1883, the first notice we 
have of the "corona" is that given in the * Japan Gazette,' September 21st, in which 
it is stated that shortly after noon on August 30th " the sun seemed to diminish 
in power, and a uniform yellowish-grey haze, gradually deepening in intensity, 
spread over the sky, and at two hours before sunset the sun's rays were blended 
into a faint halo emerging from a globe of light no larger than the full moon." 

A similar, though less definite, observation is that of M. Mareuse, at Guay- 
aquil, who reports* that the sun on September lst-5th was surrounded by a light 
atmospheric film of a coppery hue, through which the sun could scarcely shed its 
light ; it appeared like silver set in gold. 

The first detailed observation of it was, however, made by Mr, Bishop at 
Honolulu, on September 5th, simultaneously vdth that of the twilight glows and 
cloud-haze, which first reached that place on this date. 

It is important to notice his description of it, since we are thus enabled to 
establish its identity with the phenomena witnessed in Europe, America, and other 
regions, more than two months subsequently. He says (^) : — 

" Permit me to call special attention to the very pecuUar corona or halo extending 
from 20° to 30° from the sun, which has been visible every day vnth us, and all day, of 
whitish haze vdth pinkish tint, shading off into lilac or purple against the blue. I 
have seen no notice of this corona observed elsewhere. It is hardly a conspicuous object." 

Since this event it has generally been known as " Bishop's Ring," in honour of 
its first discoverer. 

Next we have an observation on September 8th, on board the Sbotia, in 
10° N. and 53° E., of a "partial halo forming at times round the sun." 

The Thesmlus, on September 16th, in 28° 29' S. and 81° 45' K, reports "a 
red haze round the moon all night." 

On September 15th, the Carola, in 14°-8 N., 20°-8 W., mentions "a halo as 

* * L'Astronomio/ Flammabion. 



ON THE LAEGE CORONA nOlTSB THE SUN AND MOON. 233 

visible round the moon, having a deep red outer margin" (^) This observation on 
board the Carola is very important in showing that the ring round the sun was not 
the ordinary ice-crystal refraction halo, in which the red band is innermost, but a true 
diffraction corona, in which the red occurs on the outside border. This reddish or 
coppery border was frequently observed without its ring-character being specially 
noted. Thus, on September 16th, Mr. Maxwell Hall, in Jamaica, observed "an 
unusual copper colour in the sky near the sun, which was afterwards very strongly 
marked."* On September 15th, the Superb, in 10° N., 146° W., noticed a "halo " (?) 
45* in diameter. 

On September 16th, from the Coppename, 42° 0' N., 39° 29' W., a halo was 
observed round the moon at 8 p.m., which may or may not have been the same 
phenomenon. After this, we have some observations within the tropics in October, 
which point distinctly to the same corona which was afterwards observed more generally. 

Thus, on October 2nd, the Orissa, in 18° 17' N., 86° 44' E., notices a red glare or 
halo roimd the sun, from 25° to 30° in diameter. On October 1 4th, the same ship, in 
11° 37' N., 82° 57' E., observes, from 8 p.m. to midnight, "a halo or circle round 
the moon 45° in diameter ; " while on October 17th, the Glencaim, in 13° 34' S., 
91° 32' E., notices '^ a very broad ring round the moon of a dark reddish colour ; " 
and, in addition to these, we have, on October 10 th, Mr. H. Pabkeb's observation in 
Ceylon of a limar corona, the sun being normal (i.e., the green tint had gone), but 
dimmer than usual at sunrise and sunset, and on October 1 8th, at Oakwood, California, 
the s\m was seen encircled by a white ring on the day immediately preceding the 
first appearance of the twilight glows in that locality ; while on November 1st, the 
Rev. A. W. Hbyde observed, at Kailong, Lahoul (Himalaya), a white circular sheen 
round the sun, of from 40° to 80° in diameter. 

Thenceforward we have frequent evidence of the appearance of the corona in 
Europe, America, Asia, and other parts, in association with the glows and other 
phenomena in November, December, and January, and everywhere of substantially 
the same physical aspect, size, and order of colours. 

Regarding the order of the colours, while there seems to be some degree of 
divergence as to the precise quality of the tints, especially of the interior part, 
there is a general consensus of opinion as to the order being blue or white on 
the inside, and red at the border, or the reverse of that in the ice-crystal 
halo. 

A high authority. Dr. Meldrum, F.R.S., who was one of its earlier observera in 
the tropics, spoke of it at the October, 1883, meeting of the Mauritius Meteorological 
Society, as " a whitish silvery patch surrounded by a brownish fringe, with a radius of 
from 12° to 24°, according to the position of the sun." 

Other observers describe it as follows : — 

• * Jamaica Weather Report/ November, 1883. 



234 



MB. E. DOUGLAS ABCHIBALD 



TABLE I 



Date. 


Observer. 


Locality. 


Remarks. 


1883. 








C) Not. 1 


Eev. A. W. Heyde • . 


Kailong, Tiahoul, 


White inside and red outside; 






33°N.,77°B. 


never seen before. 


O Nov. 26 


Miss Annie Ley 


Lutterworth 


White, with broad halo of a pale 

pink colour. 
Whitish light, fringed with pale 


(») Nov, (end of) and Dec. 


Gapt.DeB. Capello.. 


Lisbon 


(beginning). 






orange-rose; region not cir- 
cuLu*. 


(•) Nov. 27 and Dec. 15 . 


T. W. Backhouse . . 


Sunderland 


Pink outside, with bluish centre ; 
never observed previous to 
Nov. 27, though a constant halo 
observer for 26 years. 


C) Nov., 1883, to Feb., 


Hon. Bollo Russell . . 


Richmond. • 


Inner part white, outer pale red 


1884. 




• 


or lilac. 


C) During the same time 


E. D. Archibald . . 


Tunbridge YiTells.. 


Inner part milk-white and outer 
reddish-brown. 


(•) Nov. 30 


Herr Wulst . . 


Dessau 


Silver coloured, with brownish 
border. 


(")Deo. 1 


Dr. von Bezold 


Munich . . 


W hitish in centre, with brownish 
coloured border. 


(")Deo. 12 


Professor Divers • . 


Tokio 


Silvery glare, bordered by a dasty 
reddish-brown or purplish ring. 








1884. 








(»)Jan. 2 


Herr Metzger 


Flensburg . . 


A bright blue spot with a reddish 
border. 


(") Dec. and Jan. 


Dr. Galle .. 


Breslau • • 


The periphery was weak, brownish 
pale red, and inside a white 














gleam ; inner diameter 20*^, 








outer diameter 40°. 


COFeb. 8 


Professor Le Conte . • 


Calif omia . . 


Whitish glare of 20° to 25=^ 
radius. 


(«) From Nov., 1883, to 


M. ThoUon . . 


Nice 


Glowing white, very slightly tinted 


July, 1884. 






with red outside and blue inside. 


(") May 19, 1884 


Prof. Ricc5 . . 


Palermo . . 


Outer rim violet. 


(") Deo., 1883, to May, 

1884. 
(") Sept. 22, 1884 •. 


Dr. Assmann 


Magdeburg 


Outer rim brown-violet. 


Prof. A. Comu 


Paris 


Order of tints of corona from 








within outwards, blue, neutral 








grey, brown-yellow, coppery- 
red, purple-red, dull violet. 









The preceding descriptions, which by no means exhaust the entire category, but 
which we have casually selected to exhibit their general similarity, and the universal 
character of the phenomenon, show that the sun was surrounded by a white space 
bordered by a (circular or elliptical) reddish rim ; and though there are considerable 
differences in the description of the precise tint of both the interior and the border, 
the substantial identity of the phenomenon in different parts of the world cannot be 
questioned. 

Persons differ much in their estimates of colour, and when one speaks of the 
interior as blue and another as white, we are inclined to suspect that the colour in 



ON THE LAEGE CORONA ROUND THE SUN AND MOON. 



285 



the first case may have been partly due to contrast with the border, which would 
naturally first attract attention, and also be more likely to retain it, than the 
intensely brilliant inner space. It is probable, however, that in the present case the 
bluish tint spoken of in some cases (though the majority make it white or silvery), 
may really have had an objective presence, and that the order from within outwards 
was more that which was minutely described by Prof. Cobnu, viz. : blue, neutral grey, 
brown-yellow, coppery-red, purple-red, dull violet — analogous to the order of the 
spectrum colours, only flatter in tone. 

The average size of this coronal appendage may approximately be gathered from 
an examination of the different angular measurements (some evidently rather rough 
guesses) of its radius or its diameter by different observers. 

The following list gives nearly all we have been able to collect, including one 
or two roimd the moon : — 

TABLE 11. 



the Sun. 


Date. 


Observers. 


Locality. 






1883. 






C) 


40° [to 60°] 


From September 










5, onwards . . 


Bev. S. E. Bishop . • 
Rev. A. W. Heyde . . 


Honolulu. 


C) 


40° to 80° (?) 


November 1 . . 


Lahoul. 


(») 


50° 


Noyember 25 . . 


J.E.Clark .. 


York. 


n 


44° 


NoTember 25 . . 


Miss Annie Ley 


Lutterworth. 


(») 


40° to 46° 


December 5 . . 

1884. 


E. Marchund 


St. Genis. 


{^ 


50° 


January 13 


W. G. Brown 


Virginia. 


40° to 44° 


• • 


Dr. Kiessling 




pnner. 
(«) L2O'' 


oater.T 
33°. J 








• • 


Dr. Ejremser, . 


Schneekopi)e.* 


(") 


40° to 50 


Jannary 24 


Prof. Divers . . 


Tokio. 


(-) 


40° to 60 


February 8 • • 


Prof. Le Conte 


California. 


(») 20° 


40° 


March 24 


B. W. S 




44° to 46° 


April • • 


B. Douglas Archibald 


Tunbridge Wells. 


umer. 
(») 21° 36' 


max. intensitj. outer. 
30° 20- 42° 52' 


May 19 . . 


Prof. Ricc6 • • 


Palermo. 


inner. 


outer. 








(») 24° 


40° to 44° 


May and June * 


Dr. Assmann 


Magdeburg. 


n 


48° 
middle of outer 


July 23 • . 


D. A. Arcimis 


Madrid. 


inner. 


red. margin. 








(") 14° to 20° 


24° to 28° 36° to 44° 


Summer 


F. A. Forel . . 


Switzerland. 


n 23° 




•• 


Dr. von Bezold 


Munich. 



* 'Inserted here after the means had been taken. In computing the means, the extreme value is 
the outer diameter, and the average or single value for the inner. 



236 



MB. E. DOUGLAS ABGHIBALD 



Table II. — (continued.) 



Angpalar Diameter of Corona round 
the Moon. 


Date. 


Observers. 


Locality. 


interior. exterior. 
C) 15° 

r) - -ts" 

C) 30° 
(«) 36° 


1883. 
September 16 . . 

Ootolier 14 . . 

1884. 
January 4 
January 4 


S. Oarola .. 
S.OrisM 

Prof. Hasen . . 
Dr. Eremser 


fl4"48'N. 
120°48' W. 
f 11° 37' N. 
182° 67' E. 

U.S. 
Sobneekoppe. 



K we take the averages, excluding the doubtfully large value found by 
Rev. A. W. Heyde, at Lahoul, and Dr. Kbemser's, we find the following values for 
the corona round the sun : — 



Inner diameter. 

2r r 



Outer diameter. 
45^ 33' 



These averages accord very fairly with those of Professors R1006, Assmann, 
and FoEEL, which appear to have been the most carefully measured of the entire 
series. 

We shall, therefore, aa a probable average, take the inner white portion to be 
21^, and the entire ring up to the outer red to be 45° 30' in diameter. The diameter 
of the Ixmar ring appears to have been generally smaller, judging from the few 
observations, and this seems to be natxuul in consequence of its inferior brilliancy, 
which would tend to render the extreme red border invisible. From the obser- 
vations in the Table, there does not seem to have been, and indeed from such 
a comparatively limited series of observations it would be difficult to infer that there 
was, any sensible alteration in the size of the " corona" during the first twelve months 
of its appearance. 

Since the preceding paragraphs were written, a pamphlet entitled 'Beobach- 
tungen tiber die Dammerung und seine Beziehungen zum Bishop'schen Sonnenring,' 
by Dr. Albert Riqqenbaoh of Basle (1886), has appeared, in which the author gives 
some later observations of the diameter of the corona (Bishop's Ring), when the sun 
was at a high altitude, and a further list during 1885 of its dimensions at sunrise 
and sunset. 

From the first list we extract the following :-— 



ON THE LABGE CORONA ROUND THE SUN AND MOON, 



237 



Year. Month 


Diameter of Ring. 


Observer. 


Source. 




Inner. 


Middle. 


Outer. 


1884r-ATig. 7 .. 
Aug. 22, 23 

1886— Jan. 3-5 . . 
May 9 .. 
Jtdj 3 . . 


20° 
14° to 20° 

22° 

30° 

■ 12° 


26° to 34° 
24° to 30° 

26° 


48° 
36° to 44° 

32° to 34° 

50° 
36° to 40° 


Flogel . . 
Forel 

Kremser .. 
Bnsch 

Biggenbach, in the 
Engadine. 


' Das Wetter,' Bd. i., p. 221. 
'Archives de Geneve,' xii., 

p. 175. 
'Met. Zeit8.,'Bd.ii., p. 142. 
'DasWetter.'Bd-ii, p. 116. 


Means 


20° 12' 


27° 40' 


41° 48' 





The means from these observations do not sensibly differ from those derived from 
our former list, though there appears to be a slight falling off in the size of the inner 
and outer diameters. The individual observations, however, differ so much inter se, 
that no importance can be attached to this circumstance. The means from the entire 
series of twelve high-sun observations, from November, 1883, onwards, given by 
Biggenbach, are as follows, with our former ones for comparison : — 



Diameter of Corona. 


Ri^enbach. 


Former List. 


Inner , 

Middle of the red 

Outer 


20° 
28° 

44° 


21° 7' 

28° 10' (2 obs.) 

45° 33' 



The values will be seen to be very fairly accordant, especially when it is remem- 
bered that they were measured for the most part by different observers. The second 
Table gives the diametera of the corona at sunset from sixty-three observations taken 
at different dates in 1885, and arranged for different solar zenith distances, in order 
to exhibit the dilatation of the ring with increasing solar depression. The means are 
as follows : — 



Zenith Distance of Sun's 


Diameter ♦ of 


Centre. 


Inner bright 
space. 


Brightest part 
of red. 


Outer limit of 
red. 


60° to 78° 
81°-6 to 88°-9 
89°-l to 92°-3 


12° 

27°-8 
35° 


26° 
32°-4 

38°-4 


32°-8 

49°-2 



* Converted from radius as originally given. 
2l 



MR. E. DOUGLAS ARCHIBALD 

Dr. RiGGENBACH then gives a list of the angular distances of the brightest 
portions of the purple sunset glow from the sun, at different zenith distances of the 
latter, in order to show the close connection of the shape and extent of the glow with 
those of the corona. The mean of thirteen observations of this portion of the glow, 
gives it a radius from the suns centre of 18°* 6, or a diameter of 37^*2, the sun's 
zenith distance varying from 92°'l to 93°'8. 

The brightest part of the purple glow, in fact, commences about the middle or 
brightest part of the corona when this has reached its greatest dilatation. 

A few single observations of the corona and the purple glow are placed together 
for direct comparison : — 



1885 


Solar distance of the brighteet part. 




Corona. 


Purple glow. 


September 15 
II 16 

17 .. .. 

1) A«5 • • • ■ 


18"-6 
17°-8 
18°-7 


21°-2 
16°1 
17-2 
18°7 



The relationship between these two phenomena will be considered further on. 

Diurnal and Secular Duration of the large Corona. 

The corona round the sun appears to have continued everywhere with little 
change in its character, and only a gradual decrease in its brilliancy, from the date on 
which it was first observed up to the spring of 1886, and although not observed (or 
perhaps noticed) so soon as the twilight glows, it was subsequently seen wherever 
these occurred, and in proportion as their brilliancy waned it came more and more 
into popular notice. It i^ possible, indeed, that near the Equator, where the matter 
causing the appearances seems to have been densest, the corona may have been some- 
what modified, so as to appear merely in the form of a glare (such as was noticed by 
the brig Hazard and other ships, to surround the sun), and without the red border 
which was generally observed beyond the tropics. 

It may also possibly have been this fact which caused the remarkable absence of 
notice of the corona all over the northern parts of South America and at other 
equatorial places, when the blue and green appearance of the sun was attracting 
public attention, and that, as Mr. Bishop remarks concerning the twilight glows, 
which were more noticeable at Honolulu than at Fanning Island, the corona came 



* Radios of the inner limit of tlie red. 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 



S3& 



out in its best colours only where the matter waa less dense, and therefore, probably, 
more homogeneous. 

The following remarks regarding its secular duration at different places will show 
something of the nature of its persistence, and we have further evidence that in most 
places where it was noticed, either simultaneously with, or shortly subsequent to, the 
glows, it has continued to be seen whenever the conditions were favourable, such as a 
clear atmosphere, or a cloud which hid the sun's direct rays. 



TABLE IIL 



Period of Continuance. 



Observer or Authority. 



Locality. 



1883. 
(^) All through September . . 
(*) September 6 to December 15, 1883 
C^) November, 1883, to April 3, 1884 
(*) November 11 to 21 
(*) November, onwards 
(*°) Several weeks previous to De^ 
cember 24 



(") December to February, 1884 

188i. 
(*») February 20 to March 24 . . 

n April .. /;■ .. 



n 
n 
n 



(^) Beginning of March to end of 
April 
May 14, and for weeks back 
June and July 

May 18 to September 6 (inter- 
mittently) 
(«) July 29 to August 3 
(*•) July 22 to August 4 
C"*) November, 1883, toNovember, 1884 



Brig Hazard , . 
Rev. S. E. Bishop 
T. W. Backhouse 
Dr. Neumayer . . 
Maxwell Hall . . 



F. Perrin 

Hon. F. A. Rollo Russell 

Dr. G. F. Burder 
Rev. S. E. Bishop 



Dr. Kiessling 
C. L. Prince 
C. L. Wragge 



J. Gledhill 
W.N.Hartley.. 
Prof. F. A. Forel 
Rev. A. W. Heyde 



Pacific, from New Hanover to Honolulu. 

All through the Hawaiian Archipelago. 

Sunderland. 

Switzerland. 

Jamaica. 



Mont Fetoules. (The 

bad been seen.) 
Richmond, Surrey. 



guides said 



Clifton, Oloacestershire. 
Honolulu.* (Seen constantly since 
September 5, 1883.) 

Hamburg. 

Crowborough, Sussex. 
Adelaide. 

Halifax, Yorkshire. 

Switzerland. 

Merges. 

Lahoul, Himalaya. 



And thence Professor Forel carries on the observations almost up to date 
(October, 1886) in the following list, which he has forwarded to the Committee, 
and which ^ves all the dates on which he has seen the corona since the summer 
of 1884:— 



♦ Another observer, Mr. C. J. Lyons, carries it on to May 29, 1884, at the same place. 



2 I 2 



240 



MB. E. DOUGLAS ARCHIBALD 



Year. 


Month. 


Dates. 




July 


22, 23, 25, 26, 28, 29, 30, 3i 






August 


i, 2, 3, 4, /«. /», 20, 22, 23, 24, 25, 27, 30, 31 




1884 ..< 


September 


1, 2, 4, 5, 6, 7. 8, 12, 14, 15, 16, 17, 18 




October . . 


26, 27, 28, 29, 30, 31 






November.. 


3, 4, 8, 18, 19, 20, 23, 24, 27, 30 




« 


December . . 


2, 4, 7, 9, 11, 13, 15, 18 






Jannaiy . . 


4, 5, 8, 12, 13, 27, 29, 31 






Febmary .. 


1, 4, 6, 7, 8, 10, 12, 23, 24, 26, 27 






March .. 


7, 8, 9, 14, 15, 17, 19, 23, 31 






April 


I, 7, 8, 14, 15, 22, 24, 27, 28 






May 


5, 7, 8, 9, /0, 16, 17, 18, 19, 21, 23, 24, 25, 28, 29, 


3 


1886 


June 
July 


5, 7, 14, 15, 19, 21, 23, 25, 28 
1, 4, 10, 13, 19, 21, 27 






Aagast 


2, 4, 6, 7, 8, 9, 10, //, 13, 15, 22 






September 


4, 5, 6, 10, i3, i4, 15, 18, 24 






October . . 


2, 4, 7, 9, 15, 16, 22, 27, 30 






November. . 


1. 2, 3, 27 






December . . 


1, 2, 9, 29 






January . . 


30(?) 






Februaiy . . , . 


i9 






March . . 


14,30 




1886 


April 
M^y 


2, 10(?) 29(?) 
7 






June . . . . 


3 






July 


• • 






August .. 


..• 





Note. — The figures in italics represent observations taken during ascents above 1,000 metres ; tbe 
rest were taken in Swiss valleys at 400 metres above sea level. 



The letter is dated December 4th, 1886, and Professor Forel makes the follow- 
ing remarks : — 

"While up to October, 1885, I have noticed the appearance of the ring on the 
average ten times per mensem; in November and December, 1885, I have seen it only- 
four times per mensem. In the first months of 1886 I have only nine observations, of 
which three were doubtful, and two were taken in ascents of mountains. 

"Lastly, since July, 1886, 1 have no longer observed the phenomenon. Moreover, 
though I have been in conditions favourable for observation, and have resided during 
July and August, 1886, in the Alps of the Valais, at an elevation of over 6,000 feet, 
and have sometimes attained the altitude of 9,000 feet, I have not observed the 
slightest indication of " Bishop's Ring." My friends, who permanently reside between 
9,000 and 12,000 feet above sea-level, have informed me of the complete disappearance 
of the coloured circle. The sole observations which I have received during the last 

• In a recent letter to * Nature,' vol. xxxv., p. 601, Professor Stonb mentions the corona as invisible 
during the summer months of 1886, but visible again on October 15, since which date it has not been 
seen. 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 



241 



six months are (1) that of July the 19th, 1886, duriog the ascent of Mount 
Pleureur, 3,706 metres (12,159 feet), by MM. Kundig and Ischam, of Geneva; and 
(2) that of July the 26th, 1886, on the Col d'Herens, 3,460 metres (11,352 feet), 
by Mr. CouN Campbell, of Dundee." 

Professor Forel concludes as follows : — 

"Bishop's Ring has appeared continuously in our country from November, 1883, 
up to October, 1885. From November, 1885, to July, IS 86, it has been observed 
discontinuously. At the end of 1886 it has become no longer visible." 

Professor Ricc6, of Palermo, has also forwarded a list of observations, which, 
though it does not embrace so long a period, is interesting, as showing that the 
phenomenon w;as a universal one, and that the gaps in Professor Forel's series were 
chiefly due to local conditions, such as unfavourable weather, &c. Thus, the ring 
was observed on the following dat^s :^ 



Year. 


Month. 


Dates. 


1886 ... 


April 
May 
Jnne 
Jnly 


1, 2, 3, 4, 6, 6, 7, 8, 9, 10, 11, 12, 13, 17, 20, 26, 27, 29 

1, 2, 3, 5, 6, 7, 12, 13, 26, 27 

2, 3, 6, 6, 11, 12, 20, 21, 22, 26, 27, 28 
6,21 



If these dates be compared with those of Professor Forel it will be found that 
only ten coincide. 

Professor Ricc6 has also furnished a table of the intensity of the phenomena 
from its commencement, measured by an arbitrary scale of — 10. On taking 
monthly averages of these, where there are enough observations, we get the following 
results : — 

Mean Intensity of Corona. 

1883.— December, 6-5. 

1884.— January, 8*0; February, 8'0; March, 8*4; April, 8'6(max.); May, 5*1 ; 
June, 6'0; July, 6*3; August, 7*5; September, 6*8; October, 7*5; November, 8 '4. 

1885.— April, 2-9 ; May, 2*0 ; June, V7 (min.). 

• 

In examining the results of this latter table we must remember that the figures 
are not all intercomparable, owing to the observations having been made in different 
localities. Thus, up to May, 1884, they were made at Palermo ; in June, at different 
places while travelling from Turin to Modena; from July to the end of 1884, at 
Castelvetro, south of Modena ; and in 1885, again at Palermo, 

Taking, then, the first six and the last three months, we find a gradual rise 
up to a maximum about April, 1884 ; and since then evidence of a gradual decline 
down to June, 1885. 



242 MR. E. DOUGLAS ARCHIBALD 

This agrees with other casual evidence in making the maximum of the 
corona in Europe in the spring of 1884, and about three or four months after 
the maximum of the twilight glows in the same latitudes. Taking all the facta 
together regarding secular duration, we find that while the twilight glows 
ceased to attract attention after February, 1884, the corona survived them with 
remarkable persistence, and that even up to the spring of 1886, or nearly three 
years from the time at which it first appeared, it still remained a conspicuous 
phenomenon. 

Its diurnal duration in favourable circumstances seems to have been continuous. 
Thus, Mr. Bishop speaks of it as being ** visible every day and all day," (^) and Mr. 
T. R. Clapham, of Lancaster, remarks that the corona can be seen any day at 
mid-day when the sky is clear. 

Dr. Meldrum (^^) notices that the corona is visible " during the greater part 
of the day;" and others, such as Professor Le C!onte (California), M. Thollon, 
C. L. Prince, T. W. Backhouse, Dr. Assmann (Magdebiu-g), Professor F. A. Forel 
(Merges), C. L. Wragge (Adelaide), and the writer, show by their statements that 
this was the case all over the world. It was best seen when the lower air was free 
from dust, as, for instance, after rain, and especially when a dark cloud hid the sun 
and allowed the red rim to be seen round its border. In such circumstances, as 
Professor Forel substantially remarked, the lower strata of the atmosphere are in 
a shadow, and, therefore, the white light, which they usually disperse, no longer 
obliterates the delicate tints of the corona. (^^) 

One point deserves to be noticed in connection with the secular duration of the 
corona, viz., that while in November there was apparently a great decline in the 
brilUancy of the twilight glows at Honolulu, Mr. Bishop observed that the corona 
continued unaltered. (^^) The same fact was observed during the temporary abate- 
ments of the glow phenomena in Europe, showing evidently that the physical cause 
which produced the corona was independent of certain circumstances which regulated 
the development of the glows at sunrise and sunset. Since the glows have disap- 
peared, the survival of the corona lends additional support and importance to this 
conclusion. 

The general constancy of the corona under various meteorological conditions, 
both secular and diurnal, accords with the evidence aflforded elsewhere of the 
elevation of the stratum in which it was generated, far above ordinary atmospheric 
disturbances, though probably not above upper aerial currents of a continuous and 
general character. 

Peculiar Features of the Corona. 

It remains for us to notice certain peculiar features which were exhibited by the 
large corona after it fii'st became visible in Europe, in November, 1883 ; and also to 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 243 

point out those ia which it appears to differ from all ordinary phenomena of a similar 
nature. 

(1.) It was noticed that while the corona, during midday, and when the sun was 
at a high altitude, was nearly circular, as the latter declined towards the horizon the 
corona lengthened out, and the sun, instead of occupjring the centre of the ring, 
hecame excentric to it, towards its lower boundary. This was noticed specially by 
W. G. Brown, of Virginia ; (*') Prof. A. Kicc6, of Palermo ; 0«) Dr. Kiessling ; («*) 
T. W. Backhouse, of Sunderland ; Prof Coenu, and Dr. Meldrum. {^^) Dr. 
Bjoessung explains this excentricity as follows : — 

" At sunset the sun has constantly become excentric near the lower border of 
the central area [a diffraction field], so that when the sun has been at about 10° 
altitude a strikingly bright glowing blue spot has appeared about 23° to 22° above the 
horizon from which, when the sun has sunk lower, the first purple glow has been 
suddenly developed. These observations clearly show that the problematic purple 
glow is simply the upper portion of a very excentric diffraction image, such as can 
be experimentally formed by allowing the edge of the cloud molecules to act on a 
vertical plate of glass, the size of which molecules rapidly increase from above down- 
wards." 

This, however, does not tally with the fact noticed, amongst others by M. Cornu, 
that the lower part of the diffraction ring widens out as the sun approaches the 
horizon ; whereas, if the above cause were alone in operation it should become 
narrower and more curved at its lower edge. 

Prof. Cornu says (^®) : — 

*' The concentric reddish corona is the simplest form of the phenomenon. It 
appears in this geometrical form only when the sun is at great altitudes in the midst 
of a sky sufficiently clear ; but when the sun is lower, the lower arch of the corona 
widens and becomes more intense. Below this, on the horizon, arises a band of the 
same colour, which also widens towards the corona as if attracted thereby. This band 
gradually spreads in every direction, reaches the corona, and resolves itself into a 
sort of globe. During this metamorphosis the brilliant inner space, of a slightly 
bluish-white, remains sensibly circular, but, by an easily explained illusion, the sun 
seems to be excentric towards the lower side." 

It seems to us that this latter is the more probable interpretation of the two ; 
though, in favour of the former acting to some extent, we have the d pi^iori 
probability that dust would tend to arrange itself in the order of the sizes of 
its component particles, increasing from above downw^ards. 

Dr. Zenker, in an article on the corona,* has mathematically exhibited the 
eUipticity of the corona as the solar altitude decreases as follows : — 

Let ^ = the angular altitude of the sun above the horizon. 
* ' Met. Zeitsch; (1885), vol. ii., p. 400. 



244 MR. E. DOUGLAS ARCHIBALD 

2 p = the vertical angle of the cone made by joining the exterior rim of the 
corona to the eye. 
a, 6, the major and minor axes of the section made by this cone on the dust 

stratum when the sun is not in the zenith. 
Then we have 

a COB p 

h s/ Bin (^ -h p) sin (^— p) * 

When the sun is at the zenith, <}> = 90° and a = h, and the ring is circular. 
When the sun is on the horizon, <f> = p and ^ = oo , and the curve becomes a 

parabola. Finally, when <^ is < p, j becomes negative, and the curve is an 

hyperbola. 

Dr. A. KiGGENBACH, in his pamphlet already referred to, thus explains the 
widening of the corona as the sun approaches the horizon * : — 

" The widening of Bishop's Ring, which begins about half an hour before sunset, 
and reaches its maximum soon after sunset, arises solely from the reddening of the 
sun's light by its absorption in consequence of its longer path through the lower 
atmospheric strata ; and is to be conceived as a transmutation of the diflfraction 
image from a white source of illumination into that from a monochromatic red. At 
the same distance from the sun where, shortly before the disappearance of the 
ring, the maximum brightness of the red lies, the purple glow first makes its 
appearance." 

From this and the preceding extracts, it is evident that considerable diversity 
of opinion prevails as to the cause or causes of this particular phase of the phe- 
nomenon. 

(2.) Another feature of the corona was its variation when seen at different altitudes 
above the surface of the earth. This has been noticed both by Mr. T. W. Back- 
house, of Sunderland, and by Professor Forel, of Merges. Both observers concur in 
finding the corona more brilliant when seen through a clearer atmosphere, such as 
exists at lofty altitudes. The former describes the phenomenon as being far more 
striking on the summit of the Gomer Grat, 10,289 feet above sea level, than down 
below, and even at a height of 4000 feet it was more definite than at sea level. (^') 
Professor Forel says C^) : — " I verified the influence of altitude on the corona. 
Starting from the hospice of the Grimsel, 1870 metres (6135 feet), where the red circle 
was well defined, I saw its intensity gradually diminish as I descended into the valley 
of Hasli; at Innertkirchet, 625 metres (2051 feet), the red was imperceptible, but it 
reappeared on ascending to Rosenlaui ; and at the Grand Schiedeck, 1960 metres (6431 
feet), the corona was in its full lustre. I never saw it more brilliant than when on 
the high nSvls of the F^e, 3000 metres (9843 feet), Kh6ne, 2800 metres (9187 

* ' Beobacbtungen iiber die Dammernng,' Ac., p. 16. 



y 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 245 

feet) or Lower Aar, 2550 metres (8366 feet), glaciers," And again: — "I saw the 
corona in the Alps of the Valais and Berne from August 18th to 26th. As soon as 
I reached 1000 metres (3281 feet) the phenomenon reappeared ; at 1500 metres 
(4921 feet) it was very distinct; at 2000 metres (6562 feet) to 3000 metres 
(9843 feet) its hrilliancy was extraordinary." 

These observations are important as showing that the phenomenon essentially 
belonged to the upper aerial regions, and are easily explained by the fact that the 
dustier and the smokier air of the lower strata would tend to overpower by their 
diffused light and perhaps also to absorb the delicate mono-chromatic tints of the 
corona more than would the purer and more translucent air of the upper regions. 

Although, as we have before remarked, the corona was observed from places only 
slightly elevated above sea level to be substantially independent of weather changes, 
it was noticed to be more brilliant with certain phases of weather than others, 
especially after rain, and when the lower strata were less hazy and smoky than usual. 
In fact, the smoke of large cities, such as London and Berlin, seemed to render it 
almost invisible. Such vari^ttion, however, was plainly local and confined to the lower 
atmosphere alone. 

Certain secular changes of colour, however, independe^tly of those due to the state 
of the lower atmosphere, appear to have been noticed by a few persons, amongst whom 
was Professor G. H. Stone, of Colorado, who, in a paper presented to the Colorado 
Meteorological Association,* notices that the corona, or " sun-glow," as he terms it, 
was orange in November and December, 1883, pink or reddish-brown in April, 1884, 
and then diminished in intensity, becoming slightly orange again in the autumn of 
the same year. Since then it had become dull reddish-brown, 

** It was least intense during July and August of 1884 and 1885, It was most 
intense during November and December, 1883 and 1884." 

The same writer notices likewise certain variations of intensity with particular 
phases of weather, the inaximum of brilliancy occurring during cold weather, and 
especially before a cold storm, and he subsequently endeavours to trace a causal con- 
nection between the two ; but as the sun-glow, or corona, was in all probability formed 
in the same haze which caused the glows, and which evidently, both from its height 
and behaviour, had very little connection with the ordinary currents and movements 
of the lower atmosphere, this was mainly owing to the lower air being clearer at such 
times. 

In support of this, Mr. Helm Clayton, writing to the same journal in June, 
1886, says : — " Observations bavebe^n taken for several months on the visibility of the 
ring and of distant mountains at Blue Hill Observatory, and there has seemed to be a 
close parallelism between the two in New England. The ring has always appeared 
brightest when the mountains were clearest, and has disappeared when the mountains 

* ' American Meteorological Journal,* vol. ii., No. 11, March, 1886. 

2 K 



246 MK. B. DOUGLAS ARCHIBALD 

disappeared from view." Professor Stone's last communication, which again combats 
this view, is appended : — 

Disappearance of Bishop's Ring in Colorado.* 

" The reddish ring about the STin first distinctly appeared here (at the base of Pike's Peak) on 
Noyember 22nd, 1883. For several dajs before that date, a faint discoloration of the region about 
the sun had attracted mj attention. This gradually grew more intense, and, on the day mentioned, 
became unmistakable. The subsequent history of Bishop's Ring as seen at this place is, in brief, as 
follows : — 

'' The colour was most intense during the winter of 1883-84, and diminished in brightness from that 
time until its disappearance. At first it was visible almost all the time. Later, it appeared only at the 
time of cold storms, which were accompanied by great vertical movement of the air, or when, for any 
reason, the clouds reached to a great height. It was, on the average, bright-er during the winters than 
in the snmmers ; also, it was brighter when the sun was near the horizon. Many times in oold weather 
there has been not a trace of the ring, although the air was so clear that peaks a hundred miles distant 
were distinctly visible from the heights behind this city. At other times the ring has been very bright 
when the air was so hazy that the mountains only 10 miles away were hardly visible. During the later 
months of 1885 it was invisible most of the time, but suddenly flamed ont in wonderful intensity at the 
time of the great norther of January 9th-llth, 1886. Then for about two months it frequently 
appeared in the morning, or towards evening. During the warm months of 1886 it was not seen. On 
October 15th it appeared distinctly. About a week later it appeared very faintly a few times, and 
since then I have not been able to see a trace of it. My observatious have been made at elevations 
of from 6000 to about 18,000 feet, and there was bnt little apparent dilEerence in intensity at the 
different elevations. It is well known that the atmosphere here is, in general, very dry and trans- 
parent. 

** The difFraction -ring was often mora coppery, almost rosy, in tint at the time of the northers, and in 
the thickening haze in the upper air preparatory to hailstorms. The great intensity of the colour at 
such times, and its peculiar tint, and that, too, irrespective of the amount of haze in the lower 
atmosphere, makes it probable that the ring was in part due to difFraction on ice-particles. If so, the 
ice-particles may themselves have been due to precipitation on dust-particles. The fact that no difFrac- 
tion-ring has been seen around the sun during the past winter is not conclusive, for we have had no great 
northers, the season being unnsually mild. But the disappearance of Bishop's Ring for so long a time 
makes it certain that, even if there can be a circum-solar glow due to diffraction on ice-particles, yet 
the proper conditions for such a ring are realised only rarely, except when there is a great amount of 
volcanic dust in the air." 

♦•G. H. STONE." 
" Colorado College, Colorado Springs." 

Regarding the almost continuous change of tint of the corona from orange to 
dull reddish-brown as time went on, it appears that this was most probably due 
not to any special change in the matter which caused it, such as the introduction of 
ice coating the dust, as is suggested by Professor Stone, but was simply a result of 
the corresponding decline in intensity, allowing the less brilliant colours to be more 
absorbed by the lower air. This explanation agrees with what has already been said 
regarding the effect of change of altitude on the brilliancy of the phenomenon. 
There seems, therefore, to be no general evidence to show that any sensible variation 

• 'Nature,' vol. xxxv. (1887), p. 581. 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 247 

took place in the appearance of the phenomenon, as it would have presented itself 
from day to day to an observer on a lofty mountain, other than a gradual decline of 
brilliancy as time proceeded. This fact appears to be of considerable importance in 
relation to the proximate physical cause of the phenomenon. 

(3.) Another peculiarity of this corona is, that while ordinary coronae of small 
dimensions are frequently observed during the temporary passage of a cloud across 
the sun's disc, this large and nearly constant corona does not seem to have been 
vritnessed previous to its appearance in 1883, even by those ordinarily accustomed to 
scan the heavens. 

Thus Mr. Backhouse says : — " It has been habitual for me to scan the 
neighbourhood of the sim for halos during 25 years, and I never observed it 

previously to the date mentioned It is, therefore, very difficult for me to 

believe that the corona was visible in this country much, if at all, before last 
November." {^^) 

MM. Thollon and Perkotin (^) speak to the same eflfect, in that, while they 
had previously always found the sky clear, they "have, since November, 1883, found 
the sun surrounded by a circular zone of glowing white, very slightly tinted with red 
outside and white inside." 

The Rev. W. Clement Ley, a world-renowned sky observer, says that the corona 
was " unlike anything he ever saw before." And numerous other observers testify to 
the same effect. 

Professor von Bezold says that he noticed a white glare round the sun in former 
years, but had never before observed the brown ring. (®^) 

Obviously, then, we have-here a phenomenon which for size, brilliancy, univer- 
sality, and protracted duration, appeal's to be unique in the annals of Optical 
Meteorology. 

The Connection between the Corona, or Bishop's Ring, and the Unusual 

Twilight Glows. 

From the simultaneous appearance of these two phenomena in 1883, it has been 
supposed that they were not only due to a common cause, but were merely different 
manifestations of the same physical effects. 

The gradual blending of the former into the latter, and the similarity of the 
colour of the outside of the ring, which would be the last to survive after sunset, 
to that of the final tint of glow when near the horizon, tend to support this notion, 
which has been upheld chiefly by Dr. Riggenbach* and Professor KiESSLiNG.t 

The former refers to the connection as follows : — 

* * Beobachtungen uber die DammeniDg.' 
t * Die DammeraDgserBclieiiiungen im Jabre 1883/ 
2k2 



248 MR. E. DOUGLAS ARCHIBALD 

" The purple light begins to brighten up at that part of the sky where, at the 
sudden disappearance of the sun, one would perceive the brightest part of Bishop's 
Ring. After two or three minutes, when the extent of its area has become measure- 
able, it grows similar to the extension of the ring in size and width. Then the 
purple light increases both in the direction of the sun and in the reverse, but more 
especially in the latter, beyond the boundary of the ring, and attains its maximum 
area simultaneously with its maximum brilliancy, when the solar depression lies 
between 3 J° and 4^°. At this time the purple glow occupies the whole of the western 
sky, from about 6^ up to the zenith, and its seat is in the atmosphere from 5 to 13 
kilometres (16,400 to 42,700 feet). After some time, when the extent of surface 
covered by the glow has ceased to expand, the purple quickly withdraws towards the 
sun, and it disappears, on an average, when the whole atmosphere below 6*4 to 9*5 
kilometres (21,000 to 31,170 feet), visible from the place of observation, lies in the 
shadow. The lower part of the purple phenomenon remains after the maximum of 
light at nearly the same distance from the sun, and it is visibly nearer the sun 
than the inner part of the ring. At the brightening of the purple glow still 
higher portions of the atmosphere (perhaps up to 22 kilometres = 72,180 
feet) may emit red rays, in which case the exterior part of the purple glow 
shrinks before extinction to about an amount nearly equivalent to the interior 
part of the ring." 

Prof. KiESSLiNG has closely investigated the cause of the various phases 
included under, and exhibited during the prevalence of, the unusual twilight 
phenomena of 1883-4, and appears to attribute them all, with the exception of the 
second after-glow, to diffiaction through the elevate cloud-haze, and to consider 
them to be continuous modifications of the physical conditions which gave rise to 
Bishop's Ring throughout the day. 

He includes the ring as part of the twilight phenomenon, and after explaining 
the excentricity of the sun with respect to its circumference as it approaches the 
horizon, to be due to diflfraction through layers of particles increasing in size from 
above downwards, attributes the sudden appearance of the purple glow near the 
centre of the deformed ring to accumulated diffraction, principally of the red rays, 
through a part of the cloud stratum which receives the sun's rays horizontally for 
some considerable portion of its length. According to this explanation, we should 
have to regard Bishop's Ring as representing symmetrical diffraction through the haze 
which, when the sun sinks below the horizon, gradually merges into a special form of 
mono-chromatic diffraction by horizontal rays, and still conclude that conditions which 
might favour the development of the one phase would not necessarily promote the 
brilliancy of the other ; for, the ring, during the day, would represent the effect of the 
general diffraction through the entire layer, and would reach its maximum brilliancy 
when this layer reached its highest general homogeneity ; whereas the glow proceed- 
ing from some definite stratum or boundary of the haze might be subject to certain 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 249 

influences* which would affect portions of the haze without altering its general 
composition. 

This might account for the non-simultaneous occurrence of the secular maxima of 
the glows and of the corona, as well as for the fact that on single days, " when the 
twilight glows were most striking, the ring was not exceptionally conspicuous/'t 
At the same time, Professor Kiessling's theory leaves out reflection and trans- 
mission, which are shown in Section I. (b), p. 198, to account for the main features of 
the glows, especially of the secondary glow, which was the chief feature of the 
present series. 



In Opposition to the Views of Drs. Riggenbach and Kiessljng. 

Professor Ilico6,J in a careful rSsum^ of his observations of the twilight 
glows and attendant phenomena from December 3rd, 1883, to April 30th, 1884, 
concludes that the corona and the primary glow are not only separate phenomena, 
but are not physically related to each other in the manner indicated by Professor 

KiBSSLING. 

His reasons may be summarised as follows : — 

(1.) From calculations, taking account of refraction, the mean solar depression 
at- the disappearance of the primary glow on the horizon is 9°'5. On the other 
hand, the distance of the sim from the region of maximum brightness of the red in 
the corona is 15°*2, and from that of its exterior boundary 26°'4. 

(2.) The appearance of diverging crepuscular rays in the primary glow which 
the author, following other authorities, attributes to interception of the horizontal 
rays near the earth's surface by distant mountains, shows the primary glow to be 
due to direct and not to diffracted light. 

(3.) The unequal rate of descent of the edge of the primary glow, which on the 
average is about 1° in 1 ^ minutes, and the constant rate of descent of the corona, 
which follows the sun and descends from O'^'l? to 0°'18 per minute, or 1° in about 
5^ ininutes.§ 

The equation expressing the variation in the height of the rosy twilight is thus 
expressed by Professor Ricc6 : — 

V= 37^-13 sin ^K, 

* Such as those mentioned in Section lY. 

t Dr. AssMANN, *Met. Zeits.,' vol. i. (1884), p. 196. 

J ^Biassanto delle osservazioni dei crepnscoli rossi,' Nota i., ii., iii., 1884-5-6, R. Aocademia 
dei liiacei. 

§ Professor Ricco does not saj what happens to the corona when the snn goes below the horizon. 
Most observers saj that it fades away — whether subjectively or objectively does not seem quite clear. 



250 liR. E. DOUGLAS ARCHIBALD 

where V represents the variation per minute, and K the angular height of the edge 
of the glow above the horizon. 

The radius of the corona is found to vary according to a totally diflerent 
empirical law expressed by the following equation : — 

R = 26° - 7°16 sin f K. 

In fact the radius of the corona becomes 26° when the sun is on the horizon, as 
observed by Riggenbach * and others. 

(4.) The fact, already noticed, that in April, 1884, when the twilight glows were 
weak and rare, the corona was at its maximum intensity. Moreover, in January, 
1885, when the extraordinary glows had for some time ceased, the corona was observed 
several times very distinctly. 

(5.) Professor Ricc6 observed a special development of the corona, viz., the brown 
arc surrounding the sun at sunset from December, 1883, to December, 1884, fifteen 
times strongly marked (intensity ^ 8), followed by weaker twilight glows (intensity 
^ 5) ; and Professor Tacchini similarly observed, from January to December, 1884, 
the brown arc strongly marked and followed by weak displays of the twilight glows. 
Also the former observed the arc four times, and the latter fourteen times, not 
followed by twilight glows. 

(6.) The descending corona is not able to change, except in a slight degree, its 
form and its dimensions through atmospheric refraction. The greater obliquity of 
the diffracting stratum is not able to produce a change in the form and dimensions of 
this coloured ring, as may easily be experimentally verified with a glass sprinkled 
with lycopodium powder, and held with varying obliquity between the eye and a 
source of illumination. 

(7.) If the rosy arc (of the twilight glows) formed part of a diffraction ring, its 
6olour would be produced by the super-position of the red and the violet of two rings 
of a neighbouring order ; and in its spectrum, besides the maximum in the red, there 
should be also a maximum in the violet, which is not the case. 

Professor Ricc6, in fine, considers the extraordinary glows to have been super- 
posed on Bishop's Ring, but not produced either by it, or by diffracted rays, but, as 
far as the primary is concerned, by the direct solar rays. 

Professor Rtcc6's arguments appear to demolish in great measure Professor 
Kiessling's view that the primary sunset glow is entirely due to diffraction, and 
until they are effectively met by the latter, we incline to the view already put 
forward in Section I. (b), p. 199, in which some further considerations are urged against 
the purely diffraction hypothesis, and in favour of that which accounts for both the 
primary and the secondary glows at sunrise and sunset, mainly by reflection 
of rays already tinted by diffraction through, and absorption by, the same stratum, 

* * Beobaclitang^n iiber die Dammemng.' 



ON THE LARGE CORONA ROUND THE SUN AND MOON. ^51 

and the dust and vapour normally existing in the lower atmosphere. Regarding the 
disappearance of the ring at sunset^ Dr. Ass2(ann says : — ^' The ring was always* 
fainter a little before sunset, and soon after was quite invisible." And again, Prof. 
CoRNU* says : — " After simset the corona has the appearance of a slight haze, 
and gradually vanishes ; the colours blend with those of the setting sun, but generally 
in the higher regions, and they remind us of the finest roseate hues of the last 
winter's evenings/' 

General Opinions regarding the C!orona. 

We shall here give a brief rSsumS of some general remarks by a few of the lead- 
ing observers regarding the character and causes of Bishop's Ring. 

Dr. AssMANN,t referring to certain phenomena witnessed during an ascent of 
the Brocken, says : — " These rings and wreaths certainly gave one a strong impression 
of the existence of a thickly distributed dusty material sweeping along in close con- 
tiguity to the earth. That no form of aqueous vapour could have caused this ring is 
evident from its optical peculiarities, as also from the instructive combination which 
occurred on January 13th between 12 and 2 p.m. in the form of a portion of a regular 
solar halo and of a luminous mock-sun near the brownish-violet haze circle, the 
mock-sun being at least 2^ beyond the circle, The connection of these coloui-ed rings 
with the abnormal twilight phenomena is very probable," 

Professor H. Krone, in an article in the ' Met. Zeitschrift,' J says of the red 
region surrounding the twilight glows ; — '* This red region seems to be identical with 
the ring seen by Fai^l. I cannot, however, agree with Fall in placing this ring in 
the category of solar and lunar halos, that is to say among the interference phenomena 

which are wont to accompany light when transmitted through ice-needles 

This ring is uo other than the red region of the less refracted rays, yellow, reddish- 
yellow, and red, caused through refraction of the sun's rays by the atmosphere, 
especially with high atpaospheric pressure. . . ." 

Professor von Bf:zoLp, ip a letter to Professor Kiessling§ (October 24th, 1884), 
says : — 

** I have observed for years the bright glow during a high sun, and the bright 
spot above it when it is below the horizon. I was, therefore, so far inclined to doubt 
the argument which Clausicjs brings forward in his treatise on the colour of the 
atmosphere, that no water globules, but only water vesicles, were present in it, 
because, in the first case, the sun would always be surrounded by a large pale sim 
image of nearly 60°, which is not the fact. I often said to myself, * Such" an image is 

* * Gomptes Rendus,' vol. xcix., p. 490. 
t * Met. Zeitschrift,' vol. i. (1884), p. 197. 

t lUd,^ vol. i. (1884) ,p. 277. * Bericht iiber die vulkamsche Ausbniche des Jahrea 1883,* von 
Dr. Neumatkr. 

§ ' Das Wetter,' 1884, p. 178. 



252 MR. E. DOUGLAS ARCHIBALD 

actxially present, although its extension does not quite correspond with the conditions 
of the theory ; and I have for years inferred a connection between this glow and the 
purple light, but since no one took any interest in my twilight observations I let the 
fact drop, and confined myself to occasional observation. 

" On the other hand, in spite of the close attention I bestowed on this bright 
shine, I have never before observed the brown ring, which surprised me for the first 
time on December 1st, 1883, the same day on which the unusual twilight glows 
appeared, and which I have now very often, particularly during this autiunn, seen 
with wonderful development. I have also for the first time observed the reddish 
colours in the interstices between the clouds [in daytime] during this last winter." 

Professor Le Contb, of California, (^^) regards the ring as a difiVaction pheno- 
menon, but mixed with an imperfectly developed ice-halo, and hence accounts for the 
feebleness and blending of the tints. 

M. Thollon {^) says that the phenomenon was visible at Nice from November, 
1883, to July, 1884, and that, as he was quite certain he had never observed similar 
phenomena in former years, he concluded that some remarkable change had occurred 
in the atmosphere &om that date in that locality. He says also that the corona is 
evidently produced by diffraction through some light powder. 

Professor Forel, (®^) from an examination of European records only, concluded 
that an immense dust-cloud existed suspended in the air over Central Europe. 

Prof. CoRND* remarks that, in favourable circumstances, the order of the colours 
in Bishop's Ring is as follows : — 

*' Proceeding from the centre outwardly, clear azure blue, neutral grey, brown^ 
yellow, orange-yellow, coppery-red, purple-red, and dull violet, which is analogous to 
the succession of the colours of the first ring of diflfraction coronse presented by 
thin clouds. We can often make a direct comparison. These vivid hues are not 
always produced when the spaces open on the corona^, as a second condition is 
necessary, viz., that the hazy reds seen shall be in the shade, otherwise the colours 
are flooded with white light. This condition is evident when we follow the sun's 
beams across those spaces, since it is only beyond the reach of these rays that these 
red tints of fiery lustre are observed. These observations seem to indicate that the 
phenomenon has its fifeat far above the cumulus (perhaps above the cirrus), and that 
it acquires its most extraordinar}> intensity when viewed from spots where there is 
no terrestrial haze." 

Professor Piazzi Smyth says {^) ; — ** That such appearances [those noticed by 
him on September 3rd, 1884, and by Mr, Backhouse, in the Alps,] were produced by 
solid particles in a cold state, and not by any new gas introduced into the atmosphere, 
seems to be borne out by three sets of rather extensive solar spectroscopings which 
I have lately cai:ried out; for while there does not seem to be a single new line 
amongst the thousands of old ones, as far as I have yet examined the observations, 

* * Comptes Rendus,* vol. xcix., p. 490. 



/^ 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 253 

there is only too abundant evidence of a continued dulling of the light of the sun's 
continuous spectrum along its range. 

"This effect is, of course, more conspicuous in the faint regions at each end 
than in the bright middle, and appears to be testified to undeniably by the following 
differential observations, viz., that with a prismatic apparatus wherewith I could see 
lines in the bright regions, say, of B, C, and D, rather better than I could with 
somewhat similar but darker prisms in 1877, I could not see Brewster's line Y, and 
its companion groups in the very faint ultra-red, so well as I did then ; and could not 
see the further-away line X at all, though in 1877 it was not only clear enough, but 
far fainter lines on each side of it were visible, and micrometrically measurable. 
Neither in 1884 have I been able, with the same eye, and instrument, to see anything 
at the violet end of the spectrum of the grand banded lines H and K, though they 
formed a daily subject of observation in 1877. In 1856, I remarkably appreciated 
that an ascent to 1 1,000 feet on the Peak of Teneriffe enabled H and K to be seen 
with pecuUar distinctness and fine resolution of much of their haze at lower levels 
into sharp lines," &c. 

These observations are evidently important, not only in their negative bearing 
on the cause of the corona, but in their positive bearing on the general absorption 
exercised by the haze. 

Prof. KiESsrjNG has studied the diflfraction phenomena in the laboratory and 
also in the operations of nature, and we shall here quote the results of some of his 
experiments and remarks, as they have a very important bearing on the cause of the 
corona as well as on that of the entire range of optical effects which began in August, 
1883. 

His experiments * (a detailed account of which is appended to this section, p. 258) 
lead to the following conclusions : — 

(1.) That when the particles are of the same size, a condition which is not 
ordinarily .fulfilled in smoke and cloud, either dust, or dust and vapour together, 
transmit with solar light coloured coronae ; but that when the particles are of different 
sizes the diffraction image is colourless. 

(2.) That when the air is filtered from dust, and vapour is introduced into the 
diffraction chamber, and the temperature is lowered, no trace of diflfraction rings is 
visible with transmitted Kght. 

(3.) On introducing ordinary (and therefore dusty) air into the chamber, and 
lowering the temperature and pressure, a ring with a bluish interipr and a broad red 
border is obtained, very similar to the corona of 1883. The finest effects are 
obtained by starting with a maximum of vapour tension, the colours changing as 
the temperature and pressure are lowered, showing two marked stages. 

* Partly described in the * Meteor. Zeitschr.,' vol. i., 1884, and partly in his pamphlet, • Die 
DftmmemngsergoheinungOD im Jahre 1883/ Leipzig, 1885. 

2 L 



254 iiK. E.. DOUGLAS ARCHIBALD 

In the first, the order is as follows, from the centre outwards : — "Pale lilac, pale 
bluish-violet, bright blue, bluish-green, emerald-green, yellowish-green, greenish- 
yellow, bright orange, dark orange, pale scarlet-red, pale purple-red." 

In the second, when the temperature and pressure are much lower, the order of 
the colours from the centre is as follows : — " Pale purple-red, stone-green, luminous 
olive-green, yellowish-green, luminous bronze-yellow, orange." 

To obtain a bluish central field with a broad reddish-brown ring, a little smoke 
must be added to the vapour. 

As Prof KiESSLiNG considers the entire series of optical effect.s which began in 
August, 1883, to be due to diffiuction, we cannot here refer to his general views 
regarding the connection between tliese and the eruption of Krakatoa ; but may 
notice, with reference to the corona alone, that, according to him, the phenomenon 
may have been produced either by diffraction through dust alone, or through a 
homogeneous cloud formed round the finest dust particles. 

The necessary homogeneity in the former case, he thinks, may have arisen from 
the heavier particles of the dust clouds ejected from the volcano having been sifted 
out by gravitation, leaving the remainder so nearly of the same size that they were 
capable, by themselves, of producing the coloured difiraction phenomena. He 
mentions, also, having produced clearly coloured diffiraction rings with finely sifted 
and pulverised cement. 

Regarding the general question as to whether the haze, or whatever produced 
the corona, was solely dry dust or smoke, or partly or entirely minute ice spiculae 
formed, as Aitken would tell us they generally are, round dust nuclei, the corona 
alone does not give us a decided answer, since diffraction through such spiculffi 
might produce a corona of the same angular dimensions as that produced by dust of 
the same size and shape ; and the fact that the angular diameter of the corona in 
the present case was almost exactly the same as that of the refraction halo for ice 
prisms, viz., 45°, might be thought a suflScient reason for the absence of the latter. 
Dr. Assmann's observation, however, quoted above, of a solar halo appearing on 
January 13th, 1884, seems to make it plain that if there had been a halo produced 
in the haze, which was the seat of the ring, it would have been at once detected 
as a separate phenomenon. If, therefore, the corona was formed by ice prisms sur- 
rounding dust nuclei, it seems strange that, while the corona was always visible, 
there was no trace of a refraction halo in the same stratum, as we should be led to 
expect. 

Besides this negative evidence, there are many other considerations in favour of 
the notion that the haze which caused all the unusual optical phenomena was 
composed chiefly of dry dust. Some of these have been already noticed in Section 
I. (b), p. 195, in which certain peculiarities presented by the glows appear to find 
their explanation solely on this hypothesis. 



J 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 255 

We may here add a few more : — 

(1.) The fact that in cirrus, or cirro-stratus ice-haze, in which alone refraction 
halos are seen, coronse are seldom if ever observed. On the other hand, in the lower 
clouds, where water occurs in minute spherules (water dust), coronae are frequently 
obsei*ved* Kaemtz * says : — " CoronsB occur in the middle of cumulus, halos in cirrus/' 
Now, it can scarcely be doubted that any water vapour which occurred in the cloud 
haze would, at an elevation of from 60,000 to 120,000 feet or more, be entirely frozen 
into ice-spiculae resembling those in the cirrus. We should, therefore, by all analogy 
and experience, have expected halos rather than coronae to prevail in this elevated 
stratum. Instead of this, however, we find no traces of halos in the haze, but a per- 
sistent brilliant and immense corona such as has never before been witnessed. In the 
absence, therefore, of any special evidence to show that ice-spiculae could be formed 
and continue at such an elevation (which on meteorological and physical grounds is 
very improbable t), and of so minute a size as to produce so large a corona, or that 
they should give rise to a corona in preference to a halo, contrary to what occurs in 
the cirrus and cirro-stratus, the constant occurrence of this large corona for two 
or three years must alone be considered as evidence in favour of the haze being 
composed chiefly of dust. 

(2.) The remarks of Mr. Attken, in his paper referred to in Section IV., p. 346, 
as to the sifting rather than absorbing influence of the haze, which he proved by means 
of the polariscope. 

(3.) The peculiar effect of the haze on astronomical definition, and the effects 
witnessed diu:ing lunar eclipses (Section I. (d), p. 225) ; and 

(4.) The general evidence from Mr. Verbeek's report, that the ejecta from 
Krakatoa during its eruption on August 26th and 27th, were mainly fine and dry 
pumiceous dust, the rain of mud occurring only locally and temporarily, more than 
20 hours after the principal explosions had commenced. | 

Summary of Part IV., Section I. (e). 

Taking all the facts regarding the corona, or Bishop s Ring, together, we arrive at 
the following conclusions : — 

(1) That the date on which it was fii-st distinctly seen was September 5th, 1883, 
by Mr. Bishop at Honolulu, after which it appeared at most places where the other 
optical effects were witnessed : 

(2) That its principal colours were bluish-white in the centre, shading off into 
a reddish-brown border, the diameter of the inner space being about 21^, and the 
entire ring, to the external boundary of the red, about 45° 30'. Round the moon the 

♦ 'Meteorology,* translated by Walker, p. 431. 
t See " General Analysis,'* Section VII. 
X This point is further considered in Section VI T. 
2 L 2 



256 MR. E. DOUGLAS AECHIBALD 

only colour distinguishable was a pale-reddisb circular boundary, the apparent diameter 
of which was somewhat smaller than that round the sun : 

(3) That when it was visible it appeared all day from sunrise to sunset under 
favourable conditions : 

(4) That it reached its maximum intensity about the spring of 1884, since which 
time it gradually declined in brilliancy and visibility, down to June, 1886. Since 
this latter date it has not been seen even by one of its most careful observers, 
Professor Rioc6 : 

(5) That it was best seen at great altitudes ; and near the earth it was best seen 
on days when the air was free from ordinary dust or smoke : 

(6) That it appeared to be independent of all ordinary atmospheric disturb- 
ances : 

(7) That it was most probably formed in the haze stratum, which proximately 
caused the twilight glows and other optical phenomena : 

(8) That though a white glare, resembling its inner portion, had been observed 
in previous years by Professor von B£Z0LD, he had never before seen a corona of tho 
same size and with the marked reddish border : 

(9) That it was a diffi*action corona produced by the accompanying haze, and 
that its great size proves this haze to have been composed of exceedingly small 
particles : 

(10) That the order of 'the colours shows it to have been most probably a 
diffraction ring of the first order :* 

(11) That the occurrence of a corona in so elevated a region, as well as the 
general absence of accompanying refraction halos, tends to show that the particles 
through which the difiraction took place were solids, and dust rather tbm ice : 

(12) That while the corona was associated with the twilight glows and coloured 
Sims in being produced by the same elevated haze, it was physically distinct firom 
either, and probably contributed only very slightly to the glows, after the sun sank 
below the horizon : 

(13) That, from Dr. Kiessling^s experiments, it appears that exactly similar 
phenomena can be produced on a small scale by diffraction of the sun's rays through 
minute dust, or vapour momentarily condensed in ordinary dusty air. 

Thb Size of the Particles which Produced the Large Corona, or 

Bishop's Ring. 

The size of the particles Jias, by two observers, been estimated as follows : — 

Millimetre. Inch. 

(«7) Professor FoREL at -003 = -00011 

(«8) Herr Flogel at '001 = -00004 

• See Prof. Cornu, p. 252, and Professor Ricco, in his paper already quoted. 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 



257 



The writer of the present section, taking the mean value of the inner and outer 
diameters of the corona to be 21° and 45° 30', and taking the former to represent the 
position of the bright violet and the latter that of the red ring, obtains the following 
results : — 

The formula employed is — 

Sin^=N^, 

where — 

d = the diameter of a dust globule ; 

D= the angular diameter of the ring of the particular colour chosen ; 
X = the wave-length of the colour ; 

N= a constant whose values for the rings of the first and second orders are 
07655 and 17571 respectively.* 

We shall give the values for the first and second orders, though everything 
points to the probability of the entire corona, as seen, belonging to the first order. 

The radius to the middle of the ring is taken to be 15° 10', the value given by 
Professor Eicc6 for the position of maximum intensity. Since in diffracted spectra 
the middle of the spectrum coincides with the position of the rays of maximum 
intensity, this will give us values more probably correct than either the radius to 
the inner or to the outer boundary, both of which were less definitely marked. 

Diameter of the Particles (supposed Spherical) causing Bishop's Ring. 





• • 

• • 


Isfc Order. 


2nd Order. 


Inner diameter 21° 
Middle „ 30° 20' . . 
Outer „ 45° 30' . . 


•00165 mm. 
•00162 „ 
•00160 „ • 


•00379 mm. 
•00376 „ 
•00346 „ 


Meana 


•00159 mm. 
= •00006 in. 


•00367 mm. 
= •00014 in. 



It will be noticed that these values are very fairly accordant, the discrepancies 
showing that, if anything, the internal radius was measured somewhat too small or 
the outer too large, but the total difference is very little. 

K we take the mean of both the values from all three diameters for the first and 

second orders, we get "0001 inch, which is the same as that given by Professor 

FoREL ; but as we take the ring to have been of the first order, we shall adopt as 

the most probable value '00006 inch.t 

E. Douglas Archibald. 

* For the yalnes of these confltants the writer is indebted to Professor Stokes, P.B.S. 
t This is about three times the mean length of a wave of light. Some of the particles, however 
maj have been smaller than the length of a wave of red, and perhaps even of violet, light. 



258 MR. E. DOUGLAS ARCHIBALD 



APPENDICES TO CORONA SECTION. 

Discussion and Account of Experiments in Connection with Diffraction Coronce, and 

Bishop's Ring, by Pro/essai^ Kiessling.* 

When the sun's rays are passed through a cloud formed of sulphate of ammonia, formed by 
sulphurous acid and ammonia vapour, an image is formed, which rapidly changes in colour from a 
dark copper, through violet and crimson, to a brilliant azure blue. In a moist air these chaoges 
are more rapid than in dry. Clouds formed of phosphoric acid, sal ammoniac, and gunpowder 
smoke give the same results. In the case of the sal ammoniac cloud, steam intensifies the blue, 
and causes it to occur earlier; a steam or aqueous vapour cloud in air gives rise to colours between 
brownish-red and dark grey -blue. The green colour could not be artificially produced. Laugikb 
made an observation on the island of Ouessant [apparently a blue sun] (* Comptes Rendus,' vol. 39) in 
1854, which prompted the accurate research into the action of aqueous vapour in causing blue sun, 
made by Foubnbt in 1858 and 1859 (* Comptes Rendus,' vols. 47 and 48), and by Lissajous, March, 
1858. FouBNET found that the atmosphere was never pure white when aqueous vapour was preaeut, 
but was always more or less orange or blue. Cumulus clouds, increasing in thickness from the cir- 
cumference to the centre, showed successive phases of the phenomenon as the wind wafted them 
along. In most cases, if the sun was covered or dimmed by clouds, the borders of the neighbouring 
clouds were gilded, and the clouds themselves coloured orange. Between the orange-coloured zone and 
the sun's radiating disc is a blue space ; and if the sun passes behind a cloud-veil with more or less 
sharp contours, these become blue or dull white, or orange, according to the density of the obscuring 
cloud. (See also ' Phil. Mag.,' vol. 58, 1821, p. 234.) [He then refers to the dimmed and coloured suns 
seen in 1831 and 1883, which, he says, were apparently due to volcanic dust clouds.] 

If the diJSraction chamber be filled with moist air which has been thoroughly filtered and freed 
from dust, and the temperature be lowered, then a cloud is formed which is visible only in direct 
sunlight. It consists of very minute, very scattered, cloud particles, which do not produce the slightest 
trace of coloured difPraction rings with transmitted light ; evidently because there are too few of them in 
the chamber. A slight cloud is formed in dustless air, which resolves itself into small rain without cloud. 

On introducing a little ordinary air into the chamber, a smoky cloud is formed at once, in 
addition to the large drops of rain. If through this mixture of cloud and rain we look at a screen of 
tissue paper placed immediately behind the diaphragm of the heliostat, which is about 2 cm. broad, a 
yellowish-brown halo, with reddish-brown boundaries, is formed, just of the colour and size of the 
ordinary lunar halo. If a diminution in pi*e88ure be made to occur simultaneously with a sadden 
lowering of temperature, then larger and more distinctly coloured diffraction rings are formed, 
without the already existing diffraction image being in the slightest degree altered. Hence it follows 
that in the above-described process of condensation, the first formed cloud -particles are not vesicles 
but true water droplets ; for if, under ordinary atmospheric pressure, the first cloud- formation 
conaisted of vesicles, a rapid decrease of from 80 to 120 mm. of pressure would necessarily cause 
a rapid expansion of the vesicles and a correspondingly rapid decrease in the diameter of the first 
diffraction nngs formed thereby. But it is not so. At the first moment of decrease of pressai-e 
there is a broad central space which becomes a trifle smaller only during rapid colour changes, whereby 
it forms a group of concentric distinctly coloured rings, so that in the course of one or two seconds, 
two diffraction figures appear, one over the other, differing greatly in size and colour (the second being 
the less vivid of the two). With continued decrease of pressure the diameter of the two ring systems 
gradually diminishes simultaneously. Clausius has thoroughly discussed this subject in his 'Die 
Lichterscheinungen der Atmosphare ' (Leipzig, 1850, pp. 392, 396; *Pogg. Ann.,* vols. 76,84, and 85); and 

* Abridged and translated from * Met. Zeitschrift,' vol. (1884;, pp. 117 ei srq. 



ON THE LARGE CORONA ROUND THE SUN AND MOON. 259 

Bubichabt«Jbzler has more recently (*Pogg. Ann.,' vol. 145) endowed the vesicnlar theory with decisive 
importance. The formation of bright diffraction colours is in complete accordance With Fraunhofeb*8 
theory, that they necessitate clouds formed of particles of, as nearly as may be, the same sise. This 
presupposes the presence of a fine dust, which is ordinarily existent in the air of rooms, and in the 
atmospheric layers nearest the earth, and appears to be most efficient in acting upon light when the air 
is saturated. 

This is most readily effected when the air has passed through water at 30° to 40° C, before being 
introduced into the difiraction chamber, and when the decreased pressure causing a redaction of 
temperature is spread over at least a minute. When these conditions prevail, the development of colour 
is so intense that a sectional figure of the cone of diffraction rays emitted by the bell-glass is formed 
upon a screen of white tissue paper, placed at a distance of 1 metre . . • the colours of which, in 
specially favourable circumstances, that is, when the constituent particles of the cloud are as nearly as 
possible of the same siae, rival in intensity those of a solar spectrum of large dispersion viewed objectively. 
The amplitude of this, depending upon the size of the cloud corpuscles, varies between 10° and 30°. 
In consequence of the intimate dependence of the intensity of the light upon the uniform structure 
of the colour-producing cloads, great care is required in the objective representation of intensely bright 
diffraction images ; since only dull colours are formed when the water is too hot or too cold. 

The diffraction image undergoes a remarkable change of colour when the pressure is continually 
diminished. This, however, occurs only in the incipient stage of cloud formation, and generally 
presents two periods, at the termination of which the colour remains constant ; yet the last phases of 
the first period are so constant under some conditions, that there is no change of colour with a decrease 
of 10 to 20 mm. in pressure, and consequently of 1° to 2° C. 

The rapidity of the succession of colours depends upon the degree of humidity, and upon the rate 
at which the temperature is lowered, which would be materially influenced by the walls of the relatively 
small diffraction chamber. The dependence of the colour tone upon these two factors is very close. 
An accurate determination of it will require further investigation. The colour changes are perceived in 
the central area, as well as in the surrounding concentric rings. This can be distinctly observed — 
objectively by means of the image cast upon a transparent screen, or subjectively by direct observation 
of the sun's light which has passed through the diffraction chamber, or by interposing a transparent 
screen of tissue paper about 2 cm. in diameter, in front of the heliostat. The observation of the colour 
development in direct sunlight is attended with difficulty, partly because the eyes suffer from making 
such observations, but mainly because the images are so transitory, owing to the formation of air-layers 
of different temperatures which mix together, that the originally coloured concentric rings of the 
diffraction image are soon lost in the brighter but distinctly coloured reciprocally penetrating cloud- 
image. On this account I have investigated the colour changes in the last-mentioned ways only. 
The colours then always appear less bright, and also undergo a modification, but not an important one, 
in the higher tones of colour, namely, the yellow and the red shades. In the presence of the electric 
light the development of colour is especially interesting in modifications between blue and violet. 

At the very commencement of the depression of temperature there is originated a white, silvery 
shining, excessively thin, and thoroughly transparent cloud, of which the first, very transitory, colour 
appears to be a dull violet ; the diameter of the central field varies according to the amount of 
vapour present, between 15° and 60°. Then the following colours rapidly succeed each other in the 
central area : dull lilac, dull blue-lilac, brilliant clear blue, bluish-green, emerald-green, yellowish- 
green, greenish-yellow, bright orange, dull orange, dull scarlet, and crimson-red. This closes the 
first period. Each sacceeding colour appears to spread over the preceding one, which then contracts 
in diameter, so that an image is formed composed of richly coloured concentric rings. This 
encroachment of colour, however, does not proceed uniformly, but some rings sometimes become so 
narrow as to be indicated only by a transition tint, so that the succession of colon rs in the spectrum 
is apparently interrupted. I have not yet been able to ascertain the cause of this abnormal occurrence, 
which must stand over for future investigation. 



260 MR. E. DOUGLAS ARCHIBALD 

All the colours are mixed, but are suffused with such a peculiar soft glowing light that it is 
exceedinglj difficult to represent them hj means of water-colours. The estimation of the colours in the 
several phases of the development is rendered especially difficult, partly because the ooloar is rapidly 
dulled in consequence of the formation of fresh cloud-particles from the continuously wet walls of the 
diffraction chamber, and partly because a constant change is proceeding in the rings as well as in the 
central area, owing to the changes of temperature. A stationary condition first supervenes at the end 
of this period. This is pre-eminently the phase of the colour development, during which the omtral 
fijld is orange, the first ring a bright green, and bluish-green ; and the second, if of moderate breadth, 
comprises all shades between blue-violet and crimson-red. The whole aperture of the cone issuing 
from the diffraction appears to be nearly 40°, and in especially favourable circumstances, that is when 
the cloud is very homogeneous, it amounts to 70°. If we allow sal ammoniac clouds to rise within 
this cone, then these appear to be green-blue or pnrple-red, as soon as they catch the rays of light. 
This phase also is nearly stationary ; dull crimson in the central area, surrounded by a broad green 
and a narrow blue-violet ring. This phase may often be watched for 15 or 20 seconds without 
showing any change. 

The second period of coloar-change in the central area shows a much nanx>wer rang^ of colom^ 
which now always partake of the character of mixed colours overlapping one another. The colours 
are : crimson-red (with an approximately violet glow), stone-gray (with an approximately green glow), 
bright olive-green, yeHowish-green, bright bronxe-yellow, and orange. If the decrease of temperature (as 
a consequence of diminution of pressure) be continued, the orange becomes more red and bluish in 
tone, so that there is a sudden renewal of the colour which characterises the beginning of the second 
period, crimson-red ; then a repetition of the second period sets in, but in gradually fading colours, 
which become less distinct as the density of the cloud increases. 

As aforesaid, the development of colours is closely dependent on the humidity ; so that when there 
lias been a reduction of temperature after the introduction of rapidly succeeding streams of diy, dusiy 
air, and of air supersaturated with moisture by passage through hot water, there is often a parti- 
coloured mixture, lasting 10 to 15 seconds, glowing with all the colours of the spectrum, and forming a 
vortex of cloud particles, in which the contrast between purple-red and emerald-green interpenetrating 
cloud masses is quite sharply defined on opposite sides of the cloud mass. This seems to represent the 
same condition of things as occurs in the well-known Brasilian twilight phenomenon called ^' arrtbolj" 
which has been fully described by Bubkhabt-Jezleb. 

The dependence of the colours upon the specific nature of the medium is particularly well displayed 
if the upper part of the diffraction chamber be warmed by means of a gas flame. This checks the 
formation of the large cloud pai*ticles in the upper part of the glass. If, now, the temperature be 
lowered, and the diffraction image be such that the central area has the colour of the final orange of 
the firot period, the upper part will be green at the base and blue at the top, and will allow of the 
recognition of sharply defined colour-changes of distinctly larger radius. 

If this warming be continued so that a space at the top of the chamber at least 10 cm. deep is 
brought to a temperature of about 50° to 60^ C, and there is on the floor of the diffraction chamber 
(which must be so connected with the air-filter that all differences of pressure brought about by the 
warming and subsequent cooling may be equalised) a cold and wet sponge ; then a cloud forms itself, 
which first originates at the boundary between the upper warm and lower cold air, and rapidly spreads 
from below downwards, while the upper part of the glass gradually becomes clear. This is a condition of 
things which Alluabd regularly noticed on the Puy de D6me, in the winter of 1879-80, and especially in 
that of 1881-2, where, for example, he noticed V'S C. at Clermont and 8° C. on the Puy de D6me. If the 
sun's rays be allowed to enter the diffraction chamber parallel to this boundary, successive cloud layers 
will be seen which are distinctly marked off, one from the other, by the size of their constituent molecules, 
sharp demarcations, and distinctness of colour. The colours come out particularly bright if a reduction of 
temperature be superinduced upon that caused by diminution of pressure, and a bluish glowing cloud 
appears at the top of the chambei; to vanish again in a few seconds. The colour-changes in the several 



ON TH^: LARGE CORONA ROUND THE SUN AND MOON 261 

layers follow the same order from above downwards (as has already been described), in the central 
area with a continued fall of temperature. These colour-changes seem to have been observed by 
Alluard on the Puy de D6me, when he reports (in * Comptes Rendus/ vol. xcviii., p. 162), that " at 
sunrise and sunset we saw all the colours of the rainbow successively appear on the horizon in every 
direction." A splendid picture of cloud structure is given in the * Leipzig illustrirte Zeitung * for March 
the 8th, from a sketch by Plumindon. 

If the colour-producing cloud-layer has great vertical dimensions, diffraction rings will form round 
the sun and moon, especially when at low altitude. The difiEraction rings round the sun may be 
observed, even when only faintly developed, by pasting a black disc about the size of the sun*s image, 
on the back of a blackened glass, and looking at the sun with one eye in such a way that the sun shall 
be covered by the black disc. 

PoLARiscopic Observations by M. Cornu.* 

The corona has a considerable distui*bing influence on atmospheric polarisation, especially near the 
neutral points. Since the appearance of the corona, the relative positions of the three neutral points 
have undergone considerable changes ; moreover, four new neutral points have appeared which are 
situated in symmetrical pairs about the sun's vertical, nearly at the altitude of the solar and anti-solar 
centres. The two neutral points right and left of the sun can be readily seen by placing a piece of 
red glass between the polariscope and the eye (the face and the other eye should be well shaded) ; they 
are situated outside the red corona ; a green glass shows the neutral points less distinctly, and a cobalt 
blue glass brings them close to the sun. The intensity of the perturbation decreases then with the 
refrangibility of the emitted light; the analysis of the polariscopic phenomenon, compared with that of 
preceding years, shows that the perturbation corresponds in each point to the superposition of a beam 
polarised in a plane perpendicular to a plane passing through the sun. 

The new anti-solar pair of neutral points are, on the contrary, difficult of observation ; it requires a 
double glass {rouge a vitrail), so as to work with a light as monochromatic and refrangible as possible. 
The field of view is dark ; nevertheless the coloured bands are quito distinct when the sky is clear, 
but they can be seen for only a few minutes before sunset. There is a similar perturbation in the 
point of maximum polarisation, that is, at 90° from the sun in the vertical line. The maximum of 
polarised light, which on fine days might usually be represented by 0*75, has never exceeded 0*48 ; an 
accidental diminution in the amount of polarised light generally corresponds to a simple increase of 
haze ; but the persistent low proportion which has prevailed under all meteorological conditions, taken 
in connection with the other disturbances, appears to indicate the existence of some cause which acts 
like haze in diffusing neutral light and diminishing the apparent polarisation of blue sky. Photometric 
measurements in the neighbourhood of the sun point to the same conclusion. 

Polarimetric observations made with a red or a cobalt-blue glass show that the proportion of polarised 
light is less for the red than for the blue rays ; here again the degree of disturbance diminishes with the 
refrangibility. This very summary account will not warrant any rigorous conclusions as to the cause 
of the phenomenon, but it suffices to show that it is probably related to the eruption of Krakatoa. 



References in Section I. (e). 



0) * Nature,' vol. xxix. (1884), p. 260. 
(*) «Met. Zeitschrift,' vol. i. (1884), p. 58. 
(») MSS., dated December 8, 1884. 



* ' Comptes Rendns,* vol. xcix. (1884), p. 491, et seq. 
2 M 



262 REFERENCES IN SECTION I. (e). 

(*) • Nature,' vol. xxix. (1883), p. 103. 

(•) ' Standard/ December 26, 1883. 

(•) • Nature,' vol. xxix. (1884), p. 251. 

C) ' Quarterly Journal, Royal Met. Soc.,' February 20, 1884. 

(•) « Met. Zeitecbrift,' vol. i. (1884), p. 185. 

(*•) * ZeitBcbrift fiir Met.,' Bd. xix., p. 72. 

(") 'Nature,' vol. xxix. (1884), p. 283. 

(») * Met. Zeitscbrift,' vol. i. (1884), p. 184. 

(") « Met. Zeitscbrift,' vol. i. (1884), p. 194. 

(") 'Nature,' vol. xxix. (1884), p. 403. 

(**) * Comptes Rendns,' vol. xcviii., p. 760, and vol. xcix., p. 446. 

(") * Comptes Rendus,' vol. xcviii., pp. 1299, 1300. 

C) *Met. Zeitscbrift,' vol. i. (1883-4), pp. 196-198. 

(^•) * Comptes Rendus,' vol. xcix., pp. 488-493. 

(") 'Nature,' vol. xxix. (1884), p. 260. 

(») ' Nature,' vol. xxix. (1883), p. 130. 

(") 'Nature,' vol. xxix. (1883), p. 103. 

(") * Comptes Rendus,' vol. xcvii., p. 1515. 

(«) ' Nature,' vol. xxix. (1884), p. 309. 

(»•) 'Met. Zeitscbrift; vol. i. (1884), p. 117. 

(«) 'Nature,' vol. xxxi. (1885), p. 548. 

(«») 'Nature,' vol. xxix. (1884), p. 503. 

C) * Quarterly Journal, Royal Met. Soc.,' vol. x., April, 1884, and personal. 

(") * Comptes Rendus,' vol. xcviii., p. 1299. 

(») 'Nature,' vol. xxx. (1884), p. 324. 

(") * Comptes Rendus,' vol. xcix., p. 423. 

(«) * Zeitscbrift fiir Met.,' vol. xix. (1884), p. 72. 

(») 'Met. Zeitscbrift,' vol. i. (1884), p. 58. 

('^) Sbip's Log. 

(**) ' Am. Journ. Science,' vol. xxvii., Marcb, 1884, p. 204. 

(*») ' Met. Zeitscbrift,' vol. i. (1884), p. 57. 

(") ' Nature' vol. xxx. (1884), p. 54. 

(») ' Met. Zeitscbrift,' 1884. 

(*) * Jamaica Weatber Report ' for November, 1883, p. 5. 

(*") ' L'Astronomie,' 3rd year, February 1, p. 67. 

(**) * Quarterly Journal, Royal Met. Soc.,' vol. x., p. 154. 

(*») • Nature,' vol. xxix. (1884), p. 525. 

(") ' Hawaiian Montbly,' May, 1884, 

(") 'Met. Zeitscbrift,' vol. i. (1884), p. 117. 

(**) Summary of a * Meteorological Journal ' for 1883. 

(*•) ' Englisb Mecbanic,' September 12, 1884. 

(*') ' Nature,' vol. xxx. (1884), p. 488. 

(«) ' Nature,' vol. xxx. (1884), p. 384. 

(*•) * Comptes Rendus,' vol. xcix., p. 423. 

(^•^) 'Natufe,' vol. xxxi. (1885), p. 192. 

[^) ' Proc. Mauritius Met. Soc.,' October 27, 1883. 

(*^) MS. Letter addressed to Committee. 

(«) ' Nature,' vol. xxix. (1884), p. 549. 

(«) ' Nature,' vol. xxix. (1884), p. 309. 



REFERENCES IN SECTION I. (k). 263 

(**) ' Die Dammerangsersclieinungen und ihre ph jsikalische Erklamng/ Leipzig, 1885. 

(") * Ftoo. Mauritius Met. Soc.,' October 27, 1883, p. 11. 

(»•) * Comptes Rondus,' vol. xcix., pp. 488-493. 

H * Nature,' vol. xxx. (1884), p. 369. 

(»•) * Comptes Rendus,' vol. xcix. (1884), p. 423. ' 

(»•) * Nature,' vol. xxx. (1884), p. 511. 

(*) * Comptes Rendus,' vol. xcviii., p. 760. 

(•») * Zeitscbrift fur Met.,' vol. xix., p. 72. 

(•») • Sdence,' voL iii., p. 143. 

(•*) ' Comptes Rendus,' vol. xcviii., p. 760, and vol. xcix., p. 446. 

(•*) 'Comptes Rendus,' vol. xcviii., pp.- 1299, 1300. 

(•*) * Comptes Rendus,' vol. xdx., pp. 423-425. 

(«•) ' Nature,' vol. xxx. (1884), p. 463. 

(•^) ' Beobacbtungen des rotben Sonnenringes, Dr. Kiessling,' p. 177. 

(•^ ' Met. ZeitBchrift,' Bd, ii. (1885), p. 150. 



PART IV., SECTION II. 

General List of Dates of First Appearance op all the Optical Phenomena. 

By the Hon. Rollo Russell. 



The following general list of exceptional optical phenomena comprised records 
from upwards of 800 localities, and lias been compiled from all available sources. 
The Meteorological Council kindly allowed the writer full permission to search all the 
log-books sent in to their office; and Prof. Neumayer's papers in the ' Meteorologische 
Zeitschrifb/ and Mr. Verbeek's * Krakatau ' also have been extremely usefiil. This 
section may in fact be regarded as the epitome of the facts which in subsequent 
sections have to be considered and explained. 

The authorities are abridged as follows : — 

Verb. Rep., or Verbeek's Report . . * Krakatau,' by Mr. R. D. M. Verbeek. 

Met. Office Lof? Ship's special log at Meteorological Office. 

Met. ZeitBcbr. * Meteorologische Zeitscbrift.* 

Zeit. far Met., or Anstrian Zeitscbrift ' Zeitscbrift der Oesterreicbiscben Gesellscbaft fur Meteoro- 

logie.' 
S.S.R., or Signal Service Report . . Monthly Weather Review of the IJ.S. Signal Office. 



2m2 



264 



THE HON. ROLLO RUSSELL 



General List showing the Dates and Character of Celestial Appearances in diffei^ent 

parts of the World in 1883 and 1884. 



Place. 



Natal (Mr. NeisoD, * Know- 
ledge,' June 6, 1884). 

Brenhilda-, about 25° S. to 30'' S. 
113° E. (Mr. Dove, MS.). 



Misaheth 

(Tagliche Rundscliau, Berlin; 
' Met. Zeitschr.,* Verbeek's 
Report.) 



Date. 



Notes. 



^cf cBa— 6° 50' S., 101^ 2' E. (At 
noon, 2l8t, 8° 15' S., 102° 28' 
E., about 253 Englisli miles 
from Krakatoa.) 
(* Brit. Assoc. Report,' 1885.) 



Eatimbang (Verbeek's Report) 



A, B. Thomas (Verbeek's Re- 
port). 



Zealand (Verbeek's Report) 



Marathon-^'' 49' S. 80° 29' E. 
(Met. Office Log.) 

Tjerita (Verbeek's Report) 

Kroe (Verbeek's Report) 

Bandar; Bencoolen ; Singapore ; 
TelokBetong (Verbeek's Re- 
port). 



Feb., Ac., 1883 



March 22, 1883. 



May 20, 1883. 



May 20. 



May 20. 
May 20. 
May 20. 

May 20. 

May 21. 
May 21 to 23. 
May 21 to 23. 



Fine sunsets, gradually increasing from February to 
June. 

On March 22 sun set in a sea of golden fire. Sky, 
delicate tints of blue and green. 

At 9 a.m., near the Straits of Anjer, a white 
colamn of vapour was seen to rise very rapidly 
above Erakatoa. The height, by measurement, 
was found to be 11,000 metres. Soon a fall of 
ashes, fine, grey, and slightly yellowish, occurred ; 
and this continued till ni£;ht of 21st. On the 
morning of the 21st the light resembled that seen 
during an eclipse ; the sky was like a great dome 
of opal glass ; the sun a pale blue globe. A fall 
of ashes also occurred at 346 English miles from 
Krakatoa, in a direction S.W.-^ W., with a S.E. 
wind. Dust was still observed in the air on the 
next few days. 

In the morning a peculiar light green colour in the 
E.S.E., and from B. to E.N.E. a dark blue cloud 
reaching from horizon to zenith. At 2 p.m. 
quite dark and a fall of very fine dust, which 
lasted till 9 a.m. on the 21st. On clearing, the 
sun looked like dull silver. Sky of a dusty hue 
till May 23rd. 

At 10 a.m. a column of smoke in the direction of 
Krakatoa. From 10 a.m. to noon on 2lBt, fall of 
ashes. 

Eruption seen. Fall of ashes in morning, clouds 
of smoke rising over Krakatoa. The same phe- 
nomena observed by fishermen. 

At f> o'clock on this evening, being between Sebesi 
and Krakatoa, a black cloud was seen above 
Krakatoa, darting forth lightning incessantly. 
Rattle of explosions. Fall of ashes and stones. 

Sky lighted up like early dawn at 9 p.m. 



Great cloud above Krakatoa. Loud explosions. 

Fall of ashes, obscuring the sun. 

Detonations heard. At Telok Betong fall of ashes, 
May 21, 22. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



265 



Place. 



Date. 



Notes. 



Moeara Doea (Yerbeek's Re- 
port). 

Archer— &" 55' S. 103° E. to 
6° 5' S. 104° 10' E. (Verbeek's 
Report). 



Anjer 



Makasser, 14 miles sooth of 
Batavia. 

Tilhliurst—22r S. 29° E. (Met. 
Office Log). 

Conrad — Near sonth point of 
Krakatoa (Yerbeek's Report). 



Manich (Col. Ward, in Symons's 
* Met, Mag.,' vol. xix., 1884, 
p. 22). 

Lord Warderiy Captain Cooke — 
39° 18' S. 93° 25' E. (Met. 
Office Log). 

Belfast— ir 38' S. 31° 44' W. 
(Met. Office Log). 

FioZa-16° 11' N. 26° 55' W. 
(Met. Office Log). 



Tilkhurat—Sb'' S, 25° E. (Met. 
Office Log). 

Belfast— !&" 31' S. 31° 40' W. 
(Met. Office Log). 

Her Majesty—^" 8' S. 90° E. 
(Met. Office Log). 

FioZa— 9° 69' N. 28° 9' W. 
(Met. Office Log). 



Fiolo— 7° 43' N., about 28° W. 

Tilkhwrst—Sb'' 47' S. 19° 35' E. 
(Met. Office Log). 



May 22. 
«ay 22. 

May 22. 

May 22. 

May 22. 
May 23. 



May 9, 11, 18, 
June 7, 12, 15, 21, 
July 20, Aug. 16. 

May 24. 



May 24. 
May 24. 

May 24. 
May 26. 
May 26. 
May 27. 



May 28. 
May 31. 



In the afternoon tbe air was filled with fine par- 
ticles, like pipe-clay. 

Prom 6.30 a.m. to 1 p.m. fall of fine dust. ■ Black 
cloud above Krakatoa. 



Fire seen in the direction of Krakatoa. 

Great column of smoke, illuminated by lightning, 
seen this evening. 

Clouds deep scarlet at sunrise. A hot glarish look 
all round horizon. 

Thick rain of ashes and sulphur vapour. The 
smoke cut ofE sharply towards the east, but 
spreading out of sight towards the west. 

Fine sunsets and after-glows. 



Sunset rather peculiar, dark blue-green tints on 
horizon. 



Clouds in west partly hiding zodiacal light. 



At 4 a.m. sky almost cloudless; 8 a.m., overcast 
with a white haze, through which the sun is seen 
with a strong glare. 4 p.m., still hazy. 

"At sunset a small patch of cirro-cumxdus just over 
the sun, tinged a very lovely scarlet hue." 

Zodiacal light visible till after 8.30 p.m. 



At 9 p.m. thin haze over sky, through which larger 
stars show. 

• 

At 4 a.m. sky overcast with a layer of high stratus. 
At noon ropes and rigging found covered with a 
red dust. At 4 p.m. hazy all over ; sun's disc 
very distinct and with very bright glare, like a 
pot of melted glass. On May 26, at 4 p.m., hazy 
all over. (P Sahara dust.) 

Red dust over rigging. 

Cirrus clouds, tinged deep scarlet to the eastward, 
long before sunrise. 



266 



THE HON. EOLLO RUSSELL 



Place. 



Switzerland (CoL Ward, Sy- 
monH'B * Met. Magazine/ 
vol. xix., 1884, p. 22). 

Hispania—S6° N. 3" W. (Met. 
Office Log). 

-BeZ/w^— 27^ S. 28° W 



Belfast^Sr S. 21° W. . . 

Belfa8t-^6° S. 6° 25' W. 
Belfoit^Sr 26' S. 1° 34' W. 

Belfast^SS'' 16' S. 3° 58' E. 



Date. 



Notes. 



Anjer (Verbeek's Report) 



Belfast— S7° S. 54° E. . . 

Belfast— 37"" 34' S. 62° 36' E. . , 

Anjer (Verbeek's Report) 

Belfast— 36"" 8' S. 66"" 47' E. . 

^Belfast— 29"" Y S. 80° E. 

Belfast— 2d° 24' S. 81° 44' E. . . 

Fio7(^— 56° 28' S. 66° 30' W. 
(Met. Office Log). 

5eZ/cM^— 5^irN. 86°2rE. .. 

Belfast— S"" 52' N. 85° 52' E. . . 



Jnne. 

Jnne 1.' 
June 3. 

June 7. 

June 12. 
Jnne 13. 

June 14. 



Jnne 19. 



June 20. 

Jnne 28. 

Jnne 28 and 30. 

Jnne 29. 

July 3. 

July 5. 
July 11. 

July 15. 
July 16. 



Fine red gnnsets on the Alps. 



Sky to west deep red at snnset. 



Zodiacal light visible till after 8 p.m., and the 
light more open-hand shape than conical. 

Small light clouds crossing sky before the wind. 
When the sun is at the back of these clouds, the 
edges are beautifully tinted, pink and green 
being the most noticeable colours. 

Solar corona at 10 a.m. 

A wind-dog above the sun and another to the right 
of the sun : these were portions of a very indis- 
tinct solar halo. 

At 10 a.m. cirro-stratus, with tinted edges (green, 
pink, and orange), seen as each cloud passed 
over the sun, the sun being behind the cloud 
but near the edges of it. At 2 p.m. a solar halo 
(say 20°) and a corona at the same time. 8 p.m. 
some light cirrus passing over the moon caused 
a corona to be seen there. Similar colours in 
36° 45' S. 41° E. on June 22. 

Krakatoa emitted much smoke. Thundering sounds. 
Two strong columns of smoke were seen to rise 
up majestically on the 24th when the intervening 
clouds were driven off by wind. 

At 8.15 p.m. a perfectly clear, dark sky, on which 
the zodiacal light is plainly seen, top about 32°. 

Zodiacal light very distinct at 8 p.m. 

Violent explosions and smoke in the night. 

Zodiacal light visible till after 9 p.m. 

Zodiacal light visible till after 9 p.m. 

Clouds with tinted edges near sun. 

At 8 a.m. clouds of a brilliant red with a greenish 
sky to the N.E. 

Hazy overhead. 

6 p.m. An after-e£Pect of the san's setting was a 
bright yellow on the haze, which turns the dark 
green sea into a very pale green, and showed us 
a blue moon; this lasted 5 or 6 minutes. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



267 



Place. 



Datr. 



BelfaH—ir 3' N. 85^ 53' E. 



Krakatoa (Verbeek's Report). , 



Logansport, Indiana, 
C S. S. R.'). 



U.S. 



Madwa (Verbeek's Report) . • 
('Batavian Handelsblad ' of 
Augnst 16, 1883.) 



Wilhehn—49'' N. 7° W. (* Met. 
Zeitscbrift,' vol. i., 1884, p. 
167). 

O. 0, Loudon (Verbeek's Re- 
port). 

Europe^ near Krakatoa ('Met. 
Zeitscbrift,' February, 1884). 

Natal (Mr. Nelson, 'Know- 
ledge,' June 6tb, 1884). 

Nasbville, Tennessee, U.S. 
(* Met. ZeitBcbrift,' Feb. 
1884). 

Scotia — A little east of Singa- 
pore (Met. Office Log). 

Prinses WUhehmna (' London 
and Cbina Telegraph,' Octo- 
ber 8, 1883). 

Medea (* Proc. Roy. Dab. Soc.') 



Charles J5aZ— 16° 30' S. 106° E. 
(Captain Watson, 'Nature,' 
December 6, 1883). 

Charles Bal (Captain Watson, 
« Nature,' December 6, 1883). 

Telok Betong (Verb. Rep.). 



July 17. 



Aug. 11. 

Aug. 13. 
Aug. 14. 

Aug. 16. 

Aug. 16. 
Aug. 18. 
Aug. 22. 
Aug. 22. 

Aug. 21, 23. 
Aug. 23. 

Aug. 22 to 24. 
Aug. 22. 

Aug. 24. 
Aug. 26. 



Notes. 



At 0*30 p.m. a very brilliant solar halo, which lasted 
about an hour, with varying degrees of brightness. 
Between the halo and the sun the sky was as dark 
as indigo ; the colours of the halo itself, in their 
order, being brick-red, yellow, green, blue, and a 
broad outer border of a colour like polished steel. 
The sky was blue. 9 p.m. upper clouds from 
E.N.E. Another blue moon at sunset, seen through 
light haze. 

Enormous columns of smoke, reddish and dirty 
white. The products of the (May) eruption were 
found to have been deposited chiefly on the N. W. 
side. 

Yellow sunset, with peculiar yellow band changing 
to red. 

I Near Krakatoa, and even several miles from it, the 
air was full of ashes, and there was almost com- 
plete darkness. There were loud and continued 
reports. 

A strikingly deep and strong after-glow. 



In the morning, near Krakatoa, there was a dense 
rain of ashes. 

Black clouds over Krakatoa. Fall of fine dust. 



Remarkable sunsets on August 21 and : 



A beautiful sunset. 



Zodiacal light seen. 

Great column of smoke rose from the crater. 
Copious rain of ashes ; flashes like lightning. 



While near Sunda Strait electrical phenomena and 
showers of sand and gravel. 

At 8 p.m. in E. and N.E. a strong white haze or 
silvery glare. The same between 9 and 10 p.m. 



Silvery glare. 



Fall of adies in the evening. 



268 



THE HON. BOLLO RUSSELL 



Place. 



Fringes Wilhelmina — In Strait 
of Sunda (MS.). 

Bay of Naples (Verbeek's Re- 
port). 



Airlie—O'' 6' S. 105^9' E. CMet. 
Zeitsclirift,' Feb., 1884). 

Deli, Samatra,818 EngliBh miles 
from Krakatoa (Dr. Hagen, 
* Nature,' January 10, 1884). 

Buhy, between Palembang and 
Singapore (Verbeek's Rep.). 

Medea (*Proc. Roy. Dub. Soc.*) 



W, R. Bewe— Near St. Nicholas 
Point, Java (Verbeek's Re- 
port). 

0. 0. Loudon — In Lampong Bay 
(Verbeek's Report). 

Charlotte^ir T S. 107" 9' B. 
(* Met. Zeitschrift,' Feb., 
1884). 

W. H. Besse (Ship's Log, extract 
in Verbeek's Report). 

Scotia— r 34' N. 103° E. (Met. 
Office Log). 

Berhice — 23 English miles S. of 
Vlake Hoek (' Sydney Morn- 
ing Herald,' January 17, 1884). 

Anjer (* Ceylon Observer,' Sep- 
tember 6, 1883). 

Buitenzorg (Verbeek's Report). 

Semanka (Verbeek's Report) • . 

Kro6 (Verbeek's Report) 

Java's Firet Point (Verbeek's 
Report). 

6° 38' S. 106° E. 



Date. 



Aug. 25. 
Aug. 25, 26. 

Aug. 26. 

Aug. 26. 

• 

Aug. 26. 
Aug. 26. 

Aug. 26. 

Aug. 26. 
Aug. 26. 

Aug. 26. 
Aug. 26. 
Aug. 26. 

Aug. 26. 

Ang. 26. 
Aug. 26. 
Aug. 26. 
Aug. 26. 

Aug. 26. 



Notes. 



About 7 p.m. " shakes and heavy blows in the dis- 
tance, as from thunder, in W. and W.S.W." 

At 138 English miles south of Java's First Point 
(about 180 English miles from E[rakatoa) explo- 
sions heard during the night of 25th-26th. On 
26th sky extremely overcast and fall of ashes. 

Continual detonations. At 3 p.m. the whole ship 
shook. 

Thick white clouds "from the volcano Sipaiak/' 
more than 20 miles distant. 



Fall of ashee. 



At 2 p.m. first explosion heard. Then one every 
ten minutes. Column of dust rose at 2 p.m. to 
a height, given by one measurement at 17, and 
by another at 21 miles, the latter taken three hoars 
after first explosion. 

At 4 p.m. sky threatening, atmosphere very dose 
and smoky. 5 p.m. quick succession of heavy 
reports. 

About 5 p.m. rain of ashes and pumice stones. 



From 5 p.m. through the night loud thunderings 
and explosions. 



Heavy reports throughout afternoon and night. 
Very dark and cloudy night, continual lightning. 

Zodiacal light, 8 p.m. 

At 2 p.m. dark threatening sky. At 6 p.m. rain 
of ashes. At midnight ashes mixed with small 
pieces of pumice. 

Pitch dark at 2 p.m. 



Thunderings at 1 p.m. 

Fall of ashes in the evening. 

Loud detonations from 3 p.m. 

Sky quite overcast towards north at 2.30 p.m. At 
6.10 p.m. fall of ashes. 

Clouds red and yellow at sunset 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



269 



Place. 



Anerley — ^In tLe Stmits of 
Baiica, about 240 English 
miles N. of Krakatoa (' Na- 
ture,' November 8, 1883; 
Verbeek's Report). 



Charles Bed — In Strait of 
Sundfr (Captain Watson, 
• Nature,' December 6, 1883). 

ArdgGtean^7'' 64' S. 85° 37' B. 
(MS., extract from Log). 



Lennox Castle 
E. (MS.). 



-Equator, 91° 23' 



/ewe— About 800 to 1000 Eng. 
lish miles from Java, i.e., 4° 46' 
S. 90° E. to 7° 45' S. 93° E. 
(Captain L. Reid, MS.). 



Barharossa—r-r S. 93°-2 
(* Met. Zeitschrift '). 



E. 



Foochow— 26° N. 119° E. (MS. 
Report). 

Ceylon, Tissa Mabft Rd.ma, near 
N.E. coast (Mr. Parker, MS.). 

Ceylon, whole of, except west 
coast (Mr. Parker, MS.). 



W. H. Besse— In Strait of Snnda 
(Verbeek s Report). 



N(yrham OastleS6 English 
miles from Krakatoa (Mr. W. 
F. Stanley, ' Quar. Jour.* 
Royal Met. Soc., vol. x., 
1884, p. 189). 



Telok Betong 



Mnllaittivu, Ceylon (Mr. Hangb- 
ton, MS.). 

Eokkulai, Ceylon (Mr. Haugb- 
ton, MS.). 



Date. 



Aug. 26. 



Aug. 26. 

Aug. 26. 

Aug. 26. 

Aug. 26 to 28. 

Aug. 26. 



Aug. 26 and fol- 
lowing nigbts. 

Aug. 26. 



Aug. 27. 



Aug. 27. 



Aug. 27. 



Aug. 27. 
Aug. 27. 

Aug. 27 to Sep. 4. 



Notes. 



In tbe forenoon beard a noise like distant cannon- 
ading ; about noon tbe noise was more distinct. 
In tbe evening an arch of light rose, in a sbort 
time, from the borizon to tbe zenitb. Three 
aneroid barometers rose and fell nearly an inch, at 
sbort intervals. 

At noon, wind W.S.W., weather fine, dense black 
cloud above Krakatoa, wbicb was quite bidden, 
except close to tbe water. 

Sky all of a flare at sunset. Wind, east. Course, 
nortb. 

At noon barometer fell from 30*20 to 29*90, and 
rose again as quickly in balf an bour. 

Explosions beard and dust fell. Tbe sun bad a 
very strange appearance wben rising ; you would 
tbink tbe eartb was on fire. 



In the evening a dark bank in the S, and S.E. ; 
wbole sky peculiar red, like brigbt polisbed cop- 
per seen in bright daylight. Tbis lasted 8 or 
10 minutes and cbanged suddenly to uniform 
grey. During following nigbt frequent, but 
strikingly sbort, tbunder. 



Ligbt, like aurora borealis. 



Sounds of explosions beard day and nigbt. First 
beard at 7 a.m. 26tb. 



Explosions beard, 
and Mullaittivu. 
miles. 



Heard as far west as Mannar 
Distance about 2000 Eoglisb 



From daybreak a deep black cloud seen in the west, 
rising slowly, obscuring tbe sun and blackening 
the sky. Soon tbere was a fall of asbes, and 
most profound darkness during tbe day. Sun 
like a ball of fire on rising. 

Fall of asbeSy 18 incbes in 24 hours. 



Sky copper colour in tbe morning. Dark at 10.30 a.m , 

Sky to east murky, and rays of sun obscured. 
From 4 p.m. sun green. 

Sun and moon blue colour. 



2 N 



270 



THE HON. ROLLO RUSSELL 



Place. 



Semanka 



Anerley—92 English mi1e8 N.E. 
of Krakatoa CTimes/ Weekly 
Edition, October 12, 1883). 



ArdgouHin—Ahout T S. 85° 30' 
E. (MS. from log). 



Krod 



Straits of Banca, and Batavia. . 

Batavia (see * Batavia Dagblad,' 
* Ceylon Observer,' Ac. ; 
September 6 and 19, and No- 
vember 2, 1883). 

Bantam— 6^ 12' S. 106'' 8' B. . . 

Serang, Bantam (* Ceylon Ob- 
server,' September 6, 1883). 

H.M.S. Magpie — Labnan and 
Banguey Islands — 5° 25' N. 
115° 18' E. and 7° 19' N., 
117° 9' E. (Captain Vereker, 
'Nature/ December 13, 1883 ; 
also MS. Log). 

Tweed — Between Keeling Is- 
lands and Krakatoa, about 370 
English miles from Krakatoa 
(Verb. Rep.). 

Sea Witch — Ashore at Sour- 
abaya, Java, 

Simlor-h'' 35' S. 88° E. (Met. 
Office Log). 

5ram— 3° S. 92° E. ('Nature,' 
November 8, 1883, Captain 
Perrot). 

Barharo8sa—2°'6 S. 92°-9 E. 
C Met. Zeitschrift '). 

Charlotte— 8°-S S. 106°-7 E. 
('Met. Zeitschrift'). 

uiiVZie— 0° 32' S. 105° 57' E. 
(Captain Knight, ' Nature,' 
November 8, 1883). 



Datk. 



Aug. 27. 
Aug. 27. 

Aug. 27. 
Aug. 27. 

Aug. 27. 
Aug. 27. 

Aug. 27. 
Aug. 27, 

Aug. 27? 



Aug. 27 ? 

Aug. 27. 
Aug. 27. 
Aug. 27. 

Aug. 27. 
Aug. 27. 
Aug. 27. 



Notes. 



Between 4 and 5 a.m. red illumination of a great 
extent of sky. 

At 4.30 a.m. heavens lighted up pale yellow, of 
changing shades, lasting about 45 minutes. 
Daylight at 6 a.m. Toted darkness part of the 
day. Showers of pumice till midnight. 

Light wind, east to north. Second mate saw 
pumice falling. 

At 6 a.m. a greyish-yellow layer of dust covered 
everything. Sky grey and sun obscured. Smell 
of sulphur. 

Lurid skies. 

At 9 a.m. sky became darker, at 11 a.m. it became 
pitch dark and a fall of ashes began, sky dull 
yellow in west. Sun green on emerging. 



At 11 a,m. pitch dark and shower of stones. 

Total darkness at 11 a.m. and all the morning. 
Stones falling. 

Greenish sun and peculiar clouds to the southward 
for several days. The peculiar greenish hue of 
the sun lasted several days. 



Fall of ashes, 7 inches. 



Sounds as of heavy cannonading. Sun dim and 
smoky. 

8 p.m. very hazy. At midnight still veiy hazy. 



Showers of very fine sand, fit>m midnight 27th 
till the 29th. Constant thunderings since 26tli 
in direction of Sun^kti^. 

Pale yellow sky at sunset, then extremely bright 
silver colour, then grey. 

^Vom 8 a.m. till evening fall of ashes ; 11 a.nL, 
twijight ; 2 p.m., dark. 

Very early in the rooming, fall of fine grey sand. 
From about 3 p.m., August 26, explosions. 



ON THE FIRST APPBABANCES OF OPTICAL PHENOMENA. 



JJ71 



Place. 



Datb. 



Notes. 



Prins Frederth— On 27tli about 
700 English miles W. of Kra- 
katoa, en route for Europe 
(Verb. Rep.). 

Lennox Gastle^Ahout 4° S. 90° 
30' B. (MS.). 



Diego Garcia— 7" 13' S. 72* 23' 
E. (*Proc. Met. Soc. of 
Mauritius '). 

Rodriguez and Cargados — 19° 
48' S. 63° 10' E. and 17* S. 
60* E. ('Proc. Met. Soc. of 
Mauritius'). 

Se7cbelle8--4° S. 67° E. CProc. 
Met. Soc. of Mauritius'). 

Mauritius— 20° 10' S. 57° 35' E. 
(' Proc. Met. Soc. Mauritius ') . 

Burdwanr-Sb'' 40' S. 21° 36' E. 
(Met. Office Log). 

Keeling or Cocos Islands — 
11° 50' S. 96* 51' E. (Mr 
Ross, Verb. Rep., p. 516). 

Crowborougb, Sussex (Mr. 
Prince, ' Met. Journal ' of 
1883). 

Brani—4r 22' S, 91° 34' B. 
(Captain Perrot, see ante, p. 
48). 



Kro&, Sumatra 



Simla— 6"" 12' S. 88° 17' E. 
(Met. Office Log). 



SaloMc — 9° 15' 8. 93° 1' E. 
(' Comptes Rendus,* No. 21, 
Nov. 19, 1883). 

Couniy of Flint— &" 20' S. 92° 
4' E. (Captain Rowland, 
' Nature,' November 8, 1883). 

BarftaroMO— 3°-8 S. 93°-5 E. 
(* Neues Jahrbucb f iir Mine- 
ralogie,' 1884, ii., p. 32). 



Aug. 27 to 29. 

Aug. 27. 

Aug. 27 to 31. 
Aug. 27 to 31. 

Aug. 27. 
Aug. 27. 
Aug. 27. 
Aug. 27- 

Aug. 27. 

Aug. 28. 

Aug. 28. 
Aug. 28. 

Aug. 28. 
Aug. 28. 
Aug. 28. 



Rain of fine asbes. 



Ligbt variable airs. Gloomy. Large quantities of 
pumice floating. Heavy sbowers of fine dust 
falling, wbicb continued till September 1 in 
10° 19' S. 88° E. 

At sunset strange appearance, deep purplisb-red 
till 7.15 p.m. Sun partially obscured in tbe day- 
time. 

At Cargados, at sunset on 27tb, smoky appear- 
ance westwards, and nearly up to tbe zenith. At 
Rodriguez on and since 27tb, deep purplisb-red 
in N.W. to 7.15 p.m. 

Sky bazy all day. Sunset gorgeous, sky lurid all 
over, beams of red light. 

Sky overcast. Unusual dimness. Smoky appear- 
ance in west at sunset. 

Brilliant sunrise. 4 p.m., ligbt cirrus and cirro« 
stratus from nortb. 

From 4 p.m. on tbe 27tb to midnight on tbe 29tb, 
there was a fall of very fine dust, reaching a 
depth of half an inch. 

Sunrise phenomena exactly like those of following 
winter. 



From midnight to 11 a.m., a very large quantiiy of 
sand fell. 



Sky ashy-grey. Fine rain of ashes. 

At 2 p.m. sky very hazy, a fine white powder fall- 
ing in a constant shower, like snow ; whole ship 
covered with it. 8 p.m., sky still very hazy and 
dust falling. It looks like pumice ground into flour. 

Shower of sand in early morning, 5.30 a.m. Sky 
white. Sun reddish-yellow. Sand till 29tb. 

Great quantity of dust falling at noon. 



Before daylight, and throughout tbe day, fall of 
fine grey ashes. 



2n2 



273 



THE HON. ROLLO RUSSELL 



Place. 



Ida—r-S N. 108° 
Zeitschrift '). 



E. CMet. 



Charlotte— T'Z S. 106°-2 E. 
(*Met. Zeitechrift'). 

-irflffteZZa— 1127 English miles 
west of Java Head ; 5° 37' S. 
8«° 68' E. at noon on 28th 
(* Nature/ December 13, 
1883). 

Scotia (Captain Cato)— 6° N. 
95^ E. (Met. Office Log). 

Seychelles (Mr. Estridpre, * Na- 
ture/ November 8, 1883, and 
July 17, 1884). 



Diego Garcia and Gargados 
(M. Lecomte, ' Nature,* No- 
vember 8, 1883, and July 17, 
1884). 



Rodriguez (Mr. Wall is, * Nsr 
ture,' July 17, 1884). 

Mauritius (Dr. Meldrnm, * Proc. 
Met. Soc. of Mauritius '). 



Natal (Mr. Ncison, * Know- 
ledge,' June 6, 1884). 

Emma Pomer— 25^ S. Gl'^'S E. 
(* Met. Zeitschrift *). 

Cafitleton (Captain Diore) — 5° 
68' S. 93^^ 30' E. (Verbeek's 
Report). 

Tokio, Japan— 36** 43' N. 139° 
4;y E. ('Japan Gazette/ 
•Nature,' April 3, 1884). 

Earl Beacon$fieJd — From Eng- 
land to Calcutta via the Cape 
(MS., September 23, 188>{). 
Date and latitude and longi- 
tude not stated, but probably 
about 6° S. and 90^ E., on 
28th. 

Ardgowan-^Q" 37' S. 85° 21' E. 
(MS. from log). 



Date. 



Aug. 28. 
Aug. 28. 
Aug. 28. 

Aug. 28. 
Aug. 28. 

Aug. 28. 



Ang. 


28. 


Aug. 


28. 


Aug. 28, 29. 


Aug. 


28. 


Aug. 


28. 



Aug. 28. 



Aug. 28. 



Notes. 



Since ibis date, uninterrupted hazy air. Sun set 
red. 

Hazy air. 



" It began to rain something like sand in the morn- 
ing." Continued throughout 28th and 29th. 
Wind light, W.S.W. on 28th, cabn at times. 



At noon halo round sun, complete circle. 4 p.m., 
lower clouds from S.W. No mention of glows. 

Sun seen as through a fog, at sunset. At 5 p.m., snn 
clear and bright. A lurid glare all over the sky 
after sunset. At 6.30 p.m. much brighter, at 
6.45 it disappeared. 

Sun obscured, strange sky. At Cargados, when 
day dawned, there was a peculiar crimson color- 
ation from E. by N. to S.E. by E., and the sun, 
after rising, showed as if seen through the red 
shade of a sextant. 

Strange red threatening sky at sunset. 



Crimson dnwn. Sun red after rising. Gorgeous 
snnf?et, first of the after-glows. Sky and clouds 
yellow and red up to zenith. 

Most vivid sunsets ; also August 31 to September 
5, sky vivid red, fading into green and purple. 

Sky bright in the south in the evening. 



At 2 a.m. air loaded with fine dust which fell in 
great quantities. Still falling at 2 p.m. 

On this and following days, sun copper colour and 
rayless. Blood-red at Yokohama. 



" One morning we woke up to find everything 
covered with lava, and any amount of pumice 
stone floating round us. It lasted 4 days. You 
could not keep the dast out anywhere. At that 
time we were 900 miles from the nearest volcano 
(Sumatra)." 



Wind light and variable, S.W. to S.E. Saw 
pumice floating. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA; 



278 



Place. 



Yokohama (Mr. W. Hamilton, 
*Natnre,' December 13, 1883). 

British Empire--^ 37' S. 7T 
62' B. ('Cevlon Obseryer,' 
October 2, 1883). 



Simla— 6° 26' S. 87^ 62' E. 
(Met. Office Log). 



Oo^ename— 15° 30' N. 67° 30' 
W. (Met. Office Log). 

Amelia— we N. 62°-9 W. 
('Met. Zeitschrift'). 

Cheefoo— 37° 24' K 121° 25' B. 
(MS. Report of Lighthouse). 

Scotia— b"" N. 90° 40' E. (Met. 
Log Office). 



Mauritinfl (Dr. Meldrum, Met. 
Soc. of Maaritios Report). 

Lord TTarien— 55° 56' S. 62* 
51' W. (Met. Office Log). 



Ardgowan—b'' S. 85° E. (Mr. W. 
Hamilton, and MS. from log). 



FI«her Island— 23° 32' N. 119° 
28' E. (MS. Lighthouse Re- 
port), 

Emma Bdm€r—26°-5 S. 56°-6 B. 
('Met. Zeitscbrift). 

Simla (Captain Nicholson) — 
r 19' S. 87° 26' E. (Met. 
Office Log). 

ScoHor-A'' 9' N. 86^ 40' E. 
(Met. Office Log). 



Date. 



Aug. 29. 
Aug. 29. 

Aug, 29. 

Aug. 29. 
Aug 29. 
Aug. 29. 
Aug. 29. 

Aug. 29. 
Aug. 29. 



Aug. 29. 

Aug. 30. 

Aug. 30. 
Aug. 80. 

Aug. 80. 



Notes. 



Sun blood-red, with jets like smoke paBsing across 
its face. Lasted two days. 

From afternoon of 29th to end of 30th sun nearly 
obscured by pale yellowish haze, and a consider- 
able fall of light dnst, like Portland cement. 
Light wind, S.E. to S.W. 

A very large quantity of dust fell in the past night. 
At. 4 p.m., very hazy still, and dust falling. At 
5 p.m., sun completely obscured 15° above the 
horizon, owing to haze. 8 p.m., dust still falling. 

"Clouds appear dry, smoky, indescribable" at 
8 p.m. 

Sky at sunrise all imaginable colours ; small spot 
inS.E. 

Pale red glow, like a fire. 



8 a.m., upper clouds high and slow, from E.N.E., 
wind S. by W., and lower clouds W. ; complete 
circle round sun at noon. At 8 p.m., zodiacal 
light and radiance to eastward. 

Fiery sky before sunrise. 



At sunset the sky presented a brilliant spectacle ; 
at a considerable altitude west and east the cirro- 
stratus was tinted with a delicate i-ose colour. 
Close down on the western horizon streaks of 
pale green and yellow, the whole covered with a 
haze of roseate hue. 

Dust falling from 7 a.m. At 8 a.m., great masses of 
pumice floating. Sun appearing of a reddish 
hue through mist that surrounded it. Wind E. 
Midnight, fall of rain, greenish matter falling 
with it, covering deck like ash dust. 

About August 30, and for 4 or 5 days, fiery glow 
about 20 minutes after sunset. 



Sunset lovely colours, ending with purple. 



Very ha^ and dust falling. 



At 8 a.m., upper clouds high and slow from E. by 
N. Diverging rays and zodiacal light at sunset. 



274 



THE HON. ROLLO RUSSELL 



Place. 



Ida^rS N. 108°-4 B. (• Met. 
Zeitschrift '). 

Meda — Off north-west Cape of 
Anstralia, about 1150 Eng- 
lish miles S.S.E. of the Strait 
of SuDda ('Nature/ December 
13, 1883). 

Tokio and Yokohama, Japan 
('Japan Gazette/ ' Nature '). 



St. Helena— 16° S. 5« W W. 
(MS. from Governor). 

Corona (Captain Shearer) — 2° 
40'S.20°W. (MetOfficeLog). 

German ship— 10° N. 26° W. 
(MS. letter). 

Maranham, Braail— 2° 30' S. 
44° W. ('Met. Zeitschrift'). 

Rivas, Nicaragua, Central 
America (Dr. Earl Flint; 
S. S. R.). 

Nikko, Japan(Prof . J. M. Dixon, 
* Nature,' December 27, 

1883). 

Maranham ('Nature,' Novem- 
ber 22, 1883). 

Para— 1° 28' S. 48° 24' W. (Dr. 
van Rijckevorsel, ' Met. Zeit- 
schrift '). 

Natal (Mr. Neison, MS.) 



Emma Burner— 2^"* S. 55°-7 E. 
Met. Zeitschrift'). 

2° S. 6° E. CMet. Zeitschrift') 

Albert Beimanfir-2'''3 S. 4°-7 E. 
(* Met. Zeitschrift '). 

Aux Cayes, Hayti— 18° 30' N. 
71° 20' W. (' Met. Zeitschrift,' 
1884, p. 181). 

jgco^— About 3° N. 83° E. 
(Met. Office Log). 



Date. 



Ang. 30. 
Aug. 30. 

Aug. 30. 

Ang. 30. 
Aug. 30. 
Ang. 30. 
Aug. 30. 



Last days of Aug 
and first of Sept. 



Ang. 30 and 31. 

Aug. 31. 
End of August. 

Aug. 31. 

Ang. 31. 

Aug. 31. 
Aug. 31. 



From the end of 
Aug. to March 1, 

1884. 

Aug. 31. 



Notes. 



Sun seen as through a veil. 



Quantities of volcanic dust fell in the past night, 
that is between sunset 30th and sunrise Slst. 
Wind on shore. 



Soon after noon the sun became dim ; a yellow haze 
spread over the sky ; and on the 3l8t the sun 
was like the moon. On August 30 and 31 pale 
moon*like sun at Yokohama. 

Red light like distant fire, deep red in S.E. and 
S.W. at 4 a.m. 

A lurid glare in the sky at sunset, objects looking a 
ghastly blue. 

Bemarkable leaden sky after sunset. 



Remarkable sunset. 



Blue sun in South America. 



Sun copper colour with no brightness during the 
two or three days at the end of August. Popular 
alarm manifested. 



Squ dim at 7 a.m. 
September 6. 

Fiery after-glows. 



Pale sun August 31 to 



Yivid red sky; green and purple in the east. Con- 
tinued most remarkable on September 1,2, 3, and 5. 

Splendid sunset but less brilliant than on the SOthr 



The dark-red sun had a white and silvery sheen. 
Sun veiled with a silver-white sheen. 

Perpetual haze or dense veil round the sun. 
Zodiacal light. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



275 



Place. 



OlhersS'' 5' N. 27° 6' W. 
(Met. Office Log). 

British Envoy— W 30' N. 31* 
2(y W. (Met Office Log). 



Corotio— 1° 20' S. 21* W. 
(Met. Office Log). 



Marath<m-49° 49' S. 175** 19' 
W. (Met. Office Log). 

Cape Coast Castle— 5" N. 0° W. 
ceroid Coast Times/ Sep- 
tember 14 ; see ' Times ' of 
December 5, 1883). 

Frieda Orampp—l2°7 S. 27'*-3 
W. ('Met. Zeitschrift'). 

German ship— 10* 40' N. 26* 
80' W. (MS.). 

Queen of Cambria— d"" S. 28* W. 
(Met. Office Log). 



Eamoch (Captain Parson) — 
11° N. 25* 30' W. (Met. Office 
Log). 

Guayaqail— 2* S. 80° W. (M. 
E. Marense, in ' L* Astro- 
nomic *). 



Santiago, Chili— 33* S. 71° W. 
('Met. Zeitschrift/ March, 
1884). 

New Ireland— 3° S. 162* E. 
(Captain Tiempy, of Hazard; 
•Nature' Ja^ua??y 17, 1884). 

Frieda Orampp— 10*3 S. 27*2 
W. ('Met. Zeitschrrft'). 



Campano— 10° 36' N. 63° 16' W. 



Date. 



Aug. 31. 
Aug. 31. 

Aug. 31. 

Aug. 31. 
Sept. 1. 

Sept. 1. 
Sept. I. 
Sept. 1. 

Sept. 1. 
Sept. 1, 



From about Sept. 

1 for several 

months. 

Sept. 1. 



Sept. 2. 



Sept. 2. 



Notes. 



Clouds, light towards sundown (visible). 



Curious electric light appearance in the skj, quarter 
of an hour before sunrise, and the same about 
half an hour after sunset. Much cirrus about 
east and west horizons at each time. Sky oppo- 
site quite dark by contrast. 

At 8 a.m. a metallic sort of haze over the sky, the 
sun shining through it quite coppery. At 5 p.m., 
in about 0^ 10' S. 21° W., sun still of a coppery 
appearance. 

Deep red in west horizon at sunset. 



Sun rose like the moon. Clouds passing gave it 
different colours, rose colour, pink, &c. 



Sun lead colour at setting. 



§un blue from sunrise to 7 a.m., pale later on. 



At 8 a.m. a pecuh'ar thin haze in the aii', through 
which the sun is seen with a clearly defined cir- 
cumference, and almost white in colour. At 
8 p.m. stars dimly visible through the haze. 

4 a.m., eastern sky, before sunrise, silver-grey, 
changing to light blue, flecked with numerous 
small cirrus trimmings, pink and rosy. 

From September 1 to 5, a light, copper-coloured, 
atmospheric veil. San shining so feebly that it 
coald be seen with naked eye from 4 p.m., like a 
disc of silver upon a golden background; the 
spots also could be seen with the naked eye. 

Red glows more than ope hour before sunrise, and 
after sunset. " Sevei-al hours," according to 
Horr K. Rudolph. 

Sky^glow or gjare, 



The sun rose like a lewd plate, and remained rayless 
till near 8 a.m. The whole sky was gvey, the 
sun appearing like polished lead. 

Sun, on rising, blue, and during the day. Splendid 
colours after sunset. 



276 



THE HON. ROLLO BUSSBLL 



Place. 



Yarinas, Veneauola — 8'' 6' N. 
70° W. (Ml-. Hyde Clarke, 
•Nature/ November 22, 1883). 



Maracaybo— ir N. 72** 
('Met. Zeitschrift'). 



W. 



Paramaribo— 6° N. 55° W. 
(Dutch paper, Herr Metzgcr, 
* Nature/ January 10, 1884). 

Bogoti— 4° 43' N. 74^ 12' W. 
(Met. Zeitachi-ift ')• 

Panama— 8° 59' N. 79° 32' W. 
CNature,'December 13, 1883) . 

Ecuador— 3° S. 76° SO' W. 
('Met. Zeitschiift *). 

St. Thomas, West Indies — 
18° N. 65° W. 

Peru (* Met. Zeitschi-ift *) 

San Ohristobal— 7** 30' N. 72" 
23' W. ('Met. Zeitschrift *) 

Gartaprena, Colombia — 10° 22' 
N. 75° 32' W. (' Met. Zeit- 
Bchrift*). 

Medellin— 6° 2' N. 75° 49' W. 
(•Met. Zeitschrift'). 

Trinidad, Port of Spain — 10" 
80' N. 61^20* W. (Mr. Arnold 
in 'Times'). 

Ao^ario— 3"-7 N. 29° W. ('Met. 
Zeitschrift ')• 

Emma .Bomer— 36° S. 21° E. 
('Met. Zeitschrift'). 

Argentina— W'l S. 36°-9 W. 
('Met. Zeitschrift'). 

Ceba and neighbouring districts 
(' Straits Times,' in ' Ceylon 
Observer,' November 15, 
1883). 

Queen of Cambria, 5** 25' S. 27° 
27' W. (Met. Office Log). 

Olber»-4'' 41' S. 31° 10' W. 
(Met. Office Log). 



Date. 



Sept. 2. 



Sept. 2. 


Blue sun. 


Sept. 2 (?) 


Blue sun. 


Sept. 2. 


Blue Bun. 


Sept. 2, 3. 


Oreen sun 


Sept. 2. 


Blue Bun. 


Sept. 2. 


Blue sun. 


Sept. 2. 


Blue sun. 


Sept 2. 


At 3 p.m 



Sept. 2. 

Sept. 2. 
Sept. 2. 

Sept. 2. 
Sept. 2. 
Sept. 2. 



Beginning of Sep- 
tember. 



Sept. 2, 
Sept. 2. 



Notes. 



Sun like burnished silver £i*om Bunrise to noon, and 
from 3 p.m. to Bunset. From noon to 3 pjn., 
bluish-green. 



At 3 p.m. the snn suddenly lost its lustre and 
turned blue. Red light after sunset. 

On this and following days the sun set green. 



Sun lustreless and green, then blue, and, lastly, 
violet. A long belt of vapours along western skj. 

Sun looked like a blue ball, and after sunEet the 
sky became so red that there was supposed to be 
a great fire. 

Hazy air in afternoon. Grey sky. 



Splendid twilight colours. 

Soon after noon hazy-looking air, the sky quite 
grey. 

Blue sun and moon. 



Same haze as on September 1. 



Noon, sun obscured at intervals. At 5 ]^^rB.san 
visible through clouds, pale blue. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



25^7 



Place. 



H.M.S. Magpie (Captain Vere- 
ker, Dent Haven, North-cast 
Borneo^ Met. Office Log). 

OlherB—Ahont T S. 33^ W. 
(Met. Office Log). 

Maracaybo-10* 88' N. 71*^ 38' 
W. CMet. ZeitBchrift'). 

Medellin (* Met. Zeitschrift *) • . 



Eut4fpi^\4r S. r-9 W. CMet. 
Zeitsclirift'). 



ArgenHnor^e''^ S. 34^-6 W. 
(*Met. Zeitschrift'). 

Scotia— r 37' N. 71** B. (Met. 
Office Log). 

Burdwan—26'' 4ff S. 8^ 35' E. 
(Met. Office Log). 

Cape Town, Soath Africa—^** 
56' S. 18" 27' E. (MS.). 



Qneen of Cambria—^ 6' S. 
2r 41 W. (Met. Office Log). 



(7. Soutlumt'Hnrlhiirt — about 
1 7^N. 125° W. (CaptainDayift, 
' Nature/ April 10, 1884). 

New Hanove^—ff* S. 150'' B. 
(Hazard ; * Nature/ January 
17, 1884). 

OlherB'-W 30' S. 36* 44' W. 
(Met. Office Log). 

JS^Uerpe—VSr-Q S. 9°-9 W. 
-('Met. Zeitschrift'). 

Jennie Walker— «" 20' N. 155° 
28' W. ('Nature,' April 10, 
1884). 

Panning Wand -r-. 3° 30^ N. 
159° 18' W. (IWfr. Greig, 
* Nature,' April 10, 1884). 



Date. 



Sept. 2. 

Sept. 8. 
Sept. 3. 
Sept. 8. 

Sept. 3. 

Sept. 3. 
Sepf. 3. 
Sept. 3. 
Sept. 8. 

Sept. 3. 

Sept. 3. 

Sept. 3. 

Sept. 4. 
Sept. 4. 
Sept. 4. 

Sept. 4. 



Notes. 



Bright orange sky at sunset. 



At 4 a.m. northern hortson very red. At 7 a.m, 
strange appearance of sun, clear pale-blue colour. 

Azure sun. 



Same phenomena at sunrise as on 2nd at sunset, 
but in inverse order. Sun rose violet, then 
became blue, then green. 

Grey cloud stratum above the otimtilus and stratus 
clouds, and covering whole sky, during the last 
few days. 



Hazy, grey, damp air 
8 a.m., hazy overhead. Wind S. by W. 



At noon hazy grey air. 
towards evening. 



Magnificent sunset. Long twilight; Upper clouds 
from N.W. 

Glows began. At 6.50 p.m. the western sky was 
lit up as by a conflagration* It began at 6.30, 
more than one hour after sunset, and vanished 
at 7.15. After this date the glows diminished till 
about the 20th, when they again became striking. 

" Before stmrise the haze that is still in the air was 
fiery red, and the sikn, when it appeared, was of a 
dazzling white colour.*' Ooorse of «hip northerly. 

Most brilliant after-glow. 



Bright and remarkable glow after sunset. 



Sunset fine. 



Sun like the moon. Four rings round sun. 



Strange appearance at 5 p.m., sun greenish. Sun 
green at setting. Strange oolours in west. 



Sun in afternoon like Copper. 



2 o 



•278 



THE HON. ROLLO RU88ELL 



Place. 



Datf. 



Notes. 



'Superb — ^Mr. Dove (MS.). • . 

i Superb (Captein)— 16^ 6' S. 
148° 45' W. (Met. Office 
L Log). 



Papa— 10** 19' N. 161° 21' W. 
(Captain Bannaa ; 'Met. 
Zeitscbrift,' and MS.). 



Tapiteuea— 1° 10' S. 174° 50' E. 
(Mr. Bishop, informed by 
Mr. F. L. Clarke, MS. ; Mr. 
Clarke's letter to * Honolulu 
Advertiser '). 

Colombo. Ceylon— r N. 80° E. 
(* Ceylon Observer*). 

Jiurdwan—2b° 51' S. 7* 49' E. 
(Met. Office Log). 



Maracaybo 



Colombo, Cevlon (correspondent 
of * Standard*). 



Queen ofCambria, V 37' N. 26° 
12' W. (Met. Office Log). 

Transvaal ; Boefontein, Wak- 
kerstroom (Mr. Ballot, ^ Eng- 
lish Mechanic,' May 2, 1884) . 



Natal (Mr. Neison, 
ledge'). 



Ejiow- 



Ceylon (Mr. Parker, MS.) 



CaroZa— 4°-8 S. 15°o W. ('Met. 
Zeitscbrift '). 

OZ?;er#— Bahia, Brazil— 13° S. 
38° 30' W. (Met. Office Log.) 

Scotia— About 4° N. 62° B. 
(Met. Office Log). 



Sept. 4. 
Sept. 4. 

Sept. 4. 



Sept. 4 or 5 P 
(Western time). 

Sept. 6 or 6 P 
(Eastern time). 



Sept. 4. 



Sept. 4. 



Sept. 5. 
Sept. 5. 



Sept. 5. 



Sept. 5. 



Sept. 5. 



On or about Sept. 
6, 6, 7, and 8. 



Remarkable sunset ; before the red after-glow had 

faded, the moon rose in the dark blue sky, making 

quite an Italian picture. 
At sunset, bank of stratus along N.N.E. horizon, 

and quantities of stationary cirri along N.W. 

horizon. 

In the morning " the sky is covered with a tbin 
white layer. The sun penetrates it. Atmosphere 
looks yellow and watery. Few lower clouds," 
(Date giveft, 5th, by Eastern time.) 

For several days before September 7th (t.e., 6th, 
Western time), sky covered with a light haze, and 
sun like a dear silver disc. At 6ajn. enn can be 
viewed with naked eye. 



Strongly tinted sodiaoal light at 7.15 p.m. 



Grand sunrise. Clouds from west. 



Azure sun. 

Sun g^en and very dim at 5 p.m., like the mtynn. 
In declining, it chang'^ from yellowish-white 
to pea-green. 

Haze, similar to that observed on 3rd, in the air again 
to-night. 

Glows first observed. Generally observed from 
September 7. Began greenish-yellow^ or with a 
bluish -white glare, then red appeared above, and 
purple and violet. Disappeared from 1 to 1| 
hours after sunset. Secondary glow duller than 
the first. Most vivid till January. [See also 
Qraaf Reinet, September 20.] 

The extraordinary sunsets not seen after this date 
till January, except faintly. 

Magnificent sunsets. Sky peculiar and varying 
colours, blue and reddish-purple. During this 
week the weather was peculiar, with white and 
leaden coloured clouds. 



Sept. 6, 6, and 7. Strangely coloured sky, green in east^ red in west. 
Lasted till 1 hour 30 minutes after sunset. 



Sept. 5. 



Sept. 5. 



Sky glaring red to the northward at 4 a.nu. 



Green moon in bright blue sky, above glowing 
light red cirro-stratus. Clouds passing over moon 
also gi'een. Rare and very beautiful sight, 7 p.tA* 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



279 



Place. 



Date. 



NOTRS. 



Argentina'-ff''l N. 30°-4i W. 
(•Met. Zeitschrift*). 

Honolulu— 22^ N. 158" W. (Mr. 
Bishop, Mr. and Mrs. Whit- 
ney, MS. and * Nature,' April 
10, 1884). 



Steamer — 3 days S.of Honolulu 
(Dr. G. F. Harder, * Times,' 
December 18, 1883). 

Maalaea, MiAui, Sandwich Is. 
(Air. Atwater, * Nature,' April 
17, 1884.) 

Zealandiar— About 5° N. ; be- 
tween Honolulu and the 
Equator. (Mr. Bishop, * Na- 
ture,' October 2, 1884.) 

rSttpm-h (Mr. Dove's MS.) , . 



< 



Superb— W 17' S. 148" 46' 
W. (Met. Office Log). 



Papa— 8** 1' N. 161° 4' W. (MS.) 



Nashville, Tennessee, U.S. (Sig- 
nal Service Report.) 

Strong Island— 5* N. 163^ 6' 
E. (Miss Cathcart, ' Nature,' 
October 2, 1884.) 

Gilbert Islands— 00 172° E. 
(Mr. F. L. Clarke, ' Nature,' 
October 2, 1884). 

Pa|w— 6° 89' N. 160* 31' W. 
(Captain Bannau, MS.) 

Sup'^h (Captain)— 10° 17' S. 
148' 40' W. (Met. Office Log). 



Carola^A''-S S. 15°-5 W. (* Met. 
Zeitschrift'). 



Sept. 5. 
Sept. 5. 

Sept. 5. 
Sept. 5. 
Sept. 5. 

Sept. 5 to 8. 
Sept. 5. 



Sept. 5. 
Sept. 5, 6. 



Sept. 6 (Sept. 7 
by Eastern time). 



About Sept. 6 

(Sept. 7 by Eastern 

time). 

Sept. 6 (Westem 
time). 

Sept. 6. 



Sept. 6. 



Ashy-grey atmosphere at sunrise. 



Sun set green. Remarkable after*glow first seen. 
Seconcmry glow lasted till 7.46 p.m. Gold, 
green, and crimson colours. Corona constantly 
seen from September 5 to December 15. Misty 
rippled surface of haze. 

*' We witnessed a most curious phenomenon. The 
sun set perfectly blue, and next morning it rose 
a flaming ball of blue." 

Wonderful red glow in the early morning. 



Sun rbse blue. 



Sun like a silver ball, 
high up in the air. 



Hazy sky. Curious haze 



6 a.m., cirrus in lines from N.W. by N. to S.E. by S. 
moving from N.W. by N. ; noon, sky full oi haze 
or a sort of thin cirro-stratns, bat owing to glare 
could not distinguish which. At 6 p.m. cirro- 
stratus in lines from W.N.W. to E.S.E. drifting 
from W.N.W. ; muddy looking. 

Whole sky covered with uniform yellowish-red high 
cirro-stratus. Sun quite pale with definite rim, 
as through blue glass, without burr or halo. 

Sunset, shadows very bright. 



Very peculiar appearance of sun. Sky somewhat 
cloudy. Silvery pale blue sun, which could be 
gazed on- No bright sunshine all day. 

Obscured and coppery sun. 



Yellowish coloured sky. 
through. 



Moon aud stars shine 



At 6 a.m. beautiful finely mottled cirro-cumulus, 
stretching almost across sky from E.S.E. At 
noon sky full of dense haze so that the sun, as it 
approached the horizon, at an altitude of lO'^ or 
more, looked like a silver ball. 

Sky peculiarly coloured at sunset, east green, west 
red. Red in west visible till Ih. 30m. after sunset. 



20 2 



280 



THE HON. ROLLO EUSSELL 



Place. 



T^foW— 36*^ 33' 8., 66^ 28' B. 
(Met. Office Log). 

Ida^VT S. lOr-2 B. OMet. 

ZeitBcfariffc'). 

Babia, Olben^ir 56' 8., S8* 
27' W. (Met. Office Log.) 

Seotia-^'' 52' N. 69° B. (Met. 
Office Log.) 

Scotior^^ 5' N. 65° 16' E. (Met. 
Office Log.) 



J(2a— 4^7 8., 106*'-3 B. ('Met. 
Zeitschrift*). 

Olber^^W 50' S..38* 17' W. 
(Met. Office Log). 

C.iroZ»— About 6* N. 16° W. 
(* Met. Zeitschrift '). 



fiTiwwr*— 7^ 47' 8., 148* 40' W. 
(Met. Office Log). 

Oi^nfuegoi — At Nassau, New 
Pix>yidence, Bahamas (Cap- 
tain Faircloth ; Signal Ser- 
vice Report.) 

Tapiteuea (M8., Mr. Bishop, 
from Mr. P. L. Clarke; also 
* Honolulu Advertiser'). 

Virginia, U.S. (Mr. W. G. Brown, 
•Nature,' January 24, 1884). 

Florida (* Met. Zeitschrift '). . . 

Haslemere, Surrey (Hon. Rollo 
Russell, MS.) 

Chelsea, London (Mr. Ascroft, 
MS.) 



f Reunion (M. Pelagaud, 
•Comptes Rendus,' Januarv 
28, 1884.) 



Reunion 



Datk. 


Notes. 


Sept. 6. 


Most magnificent sunset. 


Sept. 6. 


Hazy air, very opaque. 


Sept. 6. 


Sky glaring red at 3 a»m. 


Sept. 6. 


8 a.m. Very fine sand deposited in places exposed 
to the wind. 


Sept. 7. 


Hazy round horizon. Very fine sand deposited id 
places exposed to the wind. Wind S.S.W. force 
4 to 6. Upper clouds from N.N.B. 


Sept. 7. 


Veiy hazy air. 


Sept. 7. 


Sky glaring red at 5 a.m. 


Sept. 7. 


At sunrise, like sunset yesterday (see p. 279). The 
sky seemed filled with uniformly distributed small 
misty clouds. 


Sept. 7. 


Dense haze all over the sky, as yesterday. 


Sept. 7. 


The sun at setting on September 7 cast a land 
glare over the western sky. 


Sept. 8. 
(Eastern time.) 


Sun like tarnished silver. Beautiful display of 
curious clouds, from eastern horizon to zenith, ia 
fine lines, overlaid at an angle of 45** with others. 


Sept., early in. 


Glows seen. Once in October. 


Sept. 8. 


Bed sunset. 


Sept. 8. 


Bright after-glow noted, and fine red sunset. 


Sept. 8. 


Unusual after-glow noted. 



Superbly 30' S. 148^ 2T W. 
(Met. Office Log.) 



SepK 8. 

Sept. 8. 
Sept. 8. 



Wonderful glow from this date. Zones of colour 
from horizon after sunset, green, yellow, orange, 
red, blue sky. Prom the middle of December it 
rapidly diminished. 

Illumination of sky increasing daily. 

Sky full of dense haze, attended by same phenom- 
ena as on the 6th. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



281 



Place. 



Sio Qrands^Wrom New York 
to Galveston (Captain Bur- 
rowB ; Signal Service Re- 
ports). 



Lead Hill, Arkansas, U.S. (Sig- 
nal Service Reports). 

Somerset, Mass., U.S. (Signal 
Service Reports). 

VirginiA, U.S.A, (Mr. W. G. 
Brown, * Nature,' Jannarj 31, 
1884). 

jc2ar-6"-5 S. 106°-1 E. (*Met. 
Zeitschrift '). 

Scotia—W N. 63° E. (Met. 
Office Log). 



Colombo, Ceylon ("W" in 
•Nature,' November 1, 1883). 

Iloilo, Manilla— 10° 30' N. 122° 
E. (* Comercio/ newspaper, 
Manilla ; see * Ceylon Ob- 
server,* November 5, 1883). 

Papor-^Oyi S. 163°7 W. (MS., 
Captain Bannau). 



Pelican— 10'' 4' N., 64'' 13' B. . . 

Patd Eichm€rs—S4r'e S. 17**-2 B. 
(•Met. Zeitschrift'). 

Ceylon (• Ceylon Observer *) . . 



Madras (Micbie Smith, 'Na- 
ture,' November 8, 1883). 



Datk. 



Sept. 7 to 9. 



Sept. 

Sept. 

Early in Sept, 

Sept. 8, 9. 

Sept. 8. 

Sept. 9. 
Sept. 9, 10. 

Sept. 9. 

Sept. 9. 

Sept. 9. 

Sept. 9. 

Sept. 9 to 11. 



Notes. 



For seyeral hundred miles outside its (the storm's) 
approaching periphery, the sunsets were yellow, 
and the reflection on the clouds in the east was 
fiery red; while the rising of the sun was 
characterised by a stai-tling redness of the eastern 
sky (alw^ays considered a sign of bad weather). 
The stars presented a "sprawling or spattered *' 
appearance; while the young moon was seen 
surrounded by a vapory halo of continually 
changing density. [The ship left New York at 
10 p.m. on September 5 ; and at 5 a.m. on 
September 9 was 55 miles S.S.E. of Canaveral in 
about 28° N. 80° W. The storm passed to the 
east of the ship]. 

Brilliant sunsets from September to the end of 
January, when they were declining. 

Beautiful sunsets in September and October. 



Afler-glow first noticed. 



Hnzy air; sun set as a yellow disc. 



Hazy round horizon. Still a deposit of sand found. 
Partial halo forming at times round the sun. 
Wind S.S.W., force 7, upper clouds N.E., rather 
high and slow. Moon green before setting. 

Sun green in afternoon, about half as bright as the 
moon. 

Greenish sun, like the moon. Nothing of the kind 
ever before seen by the fishermen. 



Sky at 8 a.m. still thinly veiled, and sun's rays 
tempered. Sun disappeared at 7^ altitude in the 
yellow stratum in the west. Clear lower air. 

Sun blue near zenith, green lower. Moon greenish 
in night of 9th. Sun green, 10th. . 

Air very hazy, sun set dark-red. 

Sky murky red, and sun pale blue, blueness in- 
creasing in intensity towurds setting. 

On September 9, sun silvery and rayless. On 
September 10, green at 5.43. On llth, bright 
green 5.30. Brilliant sunset effects lasting 1 
hour. Moon and stars green. 



282 



THE HON. KOLLO RUSSELL 



Place. 



8° to 16° N., and 87'* 30' to SS'' 
W E. (MS.). 

-BcZ/(M^16° 56' N. 87° 17' E. 
(Met. Office Log). 



Lard Warden — ST" 6' S., 40° 
46' W. (Met. Office Log). 



CTcwi«n^~8° to le'^ N. 83° 30' 
E. to 88° 40' B. (Captain, 
and IVof. Michie Smith in 
' Nature/ Angust 7, 1884). 

ScoHa—Ahoui 12° N. 61° E. 
(Met. Office Log). 



Wellington, N.Z.— 41° S. 176° 
E. (Dr. Hector, F.a.S., MS.). 

Ascension Island (MS., Ooyer- 
nor). 

Manipaj, Jaffna ('Ceylon Ob- 
server'). 



Dodandawa, Ceylon (Mr. In- 
gleby, *Cejlon Observer,' 
September 26). 

Madras— 13** 6' N. 80° 17' E. 
C Madras Mail'). 



Tripatore, Salem District, India 
—About 13° N. 80° B. (* Cey- 
lon Times'). 

Bellary— 15" 10' N. 76° 40' E. 
(' Ceylon Observer *). 



Calicut— 11° 12' N. 75° 48' E. 
(' Ceylon Observer '). 



Date. 



Sept. 9, 10, 11. 
Sept. 9. 

Sept. 9. 



Sept. 9, 10, 11. 

Sept. 9. 

Fept. ?. 

Sept. 
Sept. 9. 

•Sept. 9, 10. 

Sept. 9, 10, 11, 12, 
Sept. 10. 

Sept. 10. 
Sept. 10. 



Notes. 



San of bright Tivid green on risii^ and setting. 



Light brown clouds near sun all day. Two hoars 
before sunset, sun pale blue, like the moon, and 
not more difficult to look at. 

The sun sarrounded by a haze of pale yellow tint 
at noon. From 6 p.m. 'Hhe most woaderfnl 
sunset I ever beheld ; observed colours I never 
saw before. The whole of the heaveus a steel- 
grey tint, and all the brilliant colours faded away 
into the same grey. Observed a large halo round 
the moon which was quite blue at sanset." 

Green sun and moon. 



Sun green on rising; moon green before setting. 
From 8th to 11th sky covered with a thin cirro- 
stratus haze. 

Splendid sunsets began and continued till January 
31, 1884, with stnking effects. 

Remarkable sunsets began in September. 



In the evening, sun blue and fo dim as to be easily 
gazed at. No shadow at 6 p.m. Sky murky red. 
Deepen blue as sun declined. No halo, dear 
disc. 

Sun lemon colour, and not much brighter than the 
moon. 



Sun green. Blue by one account. On September 
10 sun rose blue, and was bine from 6 to 
10 a.m. 

Peculiar white sun in morning, more vividly white 
than the electric light. 



Sun faint green, and rayless on a cloudless skj, 
like the moon. Crossed by two dull-hued ill- 
defined belts, not continued, like clouds^ beyond, 
the sun's disc. 

For three quarters of an hoar before setting, snu 
green. After sunset, for fully 40 minutes, whole 
western sky lighted up by brilliant red glow, 
as of a great conflagration. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



283 



Place. 



Knmool (* Ceylon Observer').. 



Kalmanai (' Ceylon Observer ') 



Gl^gM-'922 English miles E. 
of Galle, to Galle (* Ceylon 
Observer'). 

Pnliadierakam (* Ceylon Ob- 
server'). 



Pondicberry (' Times ' of Cey- 
lon). 

Jaffna, "Ceylon ('Ceylon Ob- 
server'). 



Chittoor (Dr. Ration, ' Ceyhn 
Observer,' * Madras Mail '). 



Ootacamund (S. S. T., * Na- 
ture,' November 8, 1883). 

Tricbinopoly ('Nature,' March 
6, 1884). 

Papa— r S. 165°1 W. (MS., 
Captain Bannan). 

Greyhound — Poochin, 17 miles 
eastof Hoihow, Hainaii (MS.). 

JafFna, Ceylon (* Ceylon Ob- 
server'). 

10" 48' N. 78^ 52' E. ('Ceylon 
Observer,' October 25). 

ScoHor-l^ 23' N. 45° 41' B. 
(Met. Office Log). 

Oniipole, Son them India — 15° 
3(y N. 80° 6' B. (Rev. W. R. 
Manley, * Natnre,* October 
11, 1883). 



Date. 



Sept. 10. 



Sept. 10. 



Sept. 9, 10, 11. 



Sept. 9, 10, 11, 12. 



Sept. 10, 11, 12. 
Sept. 10, 11, 12, 

Sept. 10. 

In Sept. 
Sept. 10. 
Sept. 10. 
Sept. 10. 
Sept. 10. 
Sept. 10. 
Sept. 10. 
Sept. 9, 10. 



Notes. 



From abont 4.30 p.m. on September 10, 11, and 12, 
snn strange steely-bine or slaty-green. Snnset 
followed by very nnnsnal orange glow, lasting 
long after the ordinary time. Three days the 
same. 

In rising and setting, the snn appeared like the 
moon. The same appearance continaed morning 
and evening for three days. 

Snn bine and duU. 



Sun rose splendidly green, tnming to bine later. 
When at abont 45° it is too dazzling to look at, 
bnt even at midday it is bine, .like the moor, 
Tnms green again at setting. Moon looks bine 
after snnset ; and, in declining, gives a fiery 
light. 

Snn dim and bine. 



Snn green and dim. From the 13th snn looked as 
nsnal. On September 13 and 14 brilliant red 
light 7 to 7.15 p.m. 

This morning the colonr of the snn changed to 
blnish-green. Remained till 12thf Warm glow 
lingers in west long after snnset, quite unusual. 

A green cloud-like mist, and then a reddish mist, 
passed across the snn. 

From about this date a green sun. 



Sky still veiled with a yellow stratum. 



Sun pale green and sky red. Brilliant colours. 



Blue snn. Red light from 7 to 7.15. p.m. 



Subdued snn like moon, pearly-green at 15° above 
horison. Hazy sky. 

8 a.m. Thin cirro-stratus covering whole sky. 
Moon green before setting. 

Twilight glows first noticed, mottled smoky haze 
after sunset On September 1 1 and 12 splendid 
glows. Coloured suns. Deep red more than one 
hour after sunset. Order of colours from horizon, 
yellow, orange, ^d. 



i 



28 i 



THE HON. ROLLO RUSSELL 



Plack. 



Date. 



BeLfcut—l^r N. 85° 40' E. 
(Met Office Log). 



Elopnra, north coast of Borneo 
(Verbeek*8 Report, p. 147). 

Scotia, Red Sea (MS. and 
Met. Office Log). 



42^ S. 44° W. (-Met. Zeit^ 
Bchrift '). 

iSc7it/7er— 44"-2 S. 46°-8 W. 
(*Met. Zeitschrift'). 

Muscat— 23° 29' N. 68° 33' E. 
(MS.) 



Sept. 10. 



Sept. 10 (?) 



Sept. 11 and 
following days. 



Notes. 



Sept. 12, 18. 
Sept. 12. 

Sept. 12. 



Trichinopolj— 10° 47' N. 78° Sept 12. 

43' B. (* Ceylon Observer '). 

Wisconsin, U.S.A. (S. S. R.) . . ; Sept to Mai-ch. 

Colombo C Ceylon Observer,' Sept 9, 10, 11, 12, 
September 17, 1883). 



Madras (Prof. M. Smith, ' Na- 
tare,' Angnst 7, 1884). 

Madi-as (Mr. Pogson,* * Nature,* 
Angnat 7, 1884). 



Sept 12. 
Sept. 12. 



San blue, like moon, from 4 p.m., changing for the 
last 10 minutes before sunset slowlj to olive- 
green, and disappeared about 2° above borizoii. 
At noon liglit brown clouds like yesterday. 

Green sun. 



Sun green at rising and setting on 11th and 12th. 
Moon green at 20° altitude on September 11, 
shining through cirro-BtratuB. The glows were 
seen as far as 15° N. 42° 80' £., ship going north. 
Yellow was the lowest colour, orange inter- 
mediate, and red uppermost. At 14° T N. 42^ 
45' £. thin drro-stratus covering the whole iky. 



Splendid- sunrises and sunsets. 



Splendid sunset. Atmosphere brown and yellow on 
green background. Long white streaks of cirrus. 

OlowB began on this day. The maxima were on 
September 13, 28, and October 12 and 27. They 
lasted at least two hours after sunset. A white 
sheen appeared about 10 minutes before sunset 
Two hours before sunrise, redness like a confla- 
gration. 

Gi*een sun from about this date. 



Brilliant sunsets seen during this period. 

The Run rises a splendid green when visible, t.c, 
about 10° from the horizon. As he advances be 
assumes a beautiful blue. Then as he 

declines he assumes the same changes, but rice 
versd. The moon, now visible in the afbernoons, 
looks also tinged with blue after sunset, and as 
she declines assumes a very fieiy colour 30^ from 
the zenith. 

Sun set as a greenish-yellow ball, having been 
green a little earlier. 

At 5 a.m. on September 12 the sky a very remark- 
ably intense reddish-yellow. At 5.10 a.m., sky 
less red, but bright orange-yellow. Light enough 
to read by easily. At 5.20, sky pretty clear in 
east to sbout 20^ altitude, and rich red, rest of 
sky bright yellow. About 5.26 much l^'ss liglit, 
and dark red in east, rest of sky greenish-jellow. 
At 5.40 the low cloud-stratum (in east) eea- 
green. Much less hght to read by. At 5.50, sun 
rising, bright yellowiph-white. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



285 



Place. 



Popa— At Sydney Island, 4°'4 
S. 170^-6 W. (MS., Captain 
Bannan). 

Indian Ocean . • • • 

Scotia— 2V N. 38° E. (Met. 
Office Log). 

Q^em of Canibr{ar—U° N. 26° 
42' W. (Met. Office Log). 



Colombo, Ceylon (* Knowledge,' 
Dec. 14, 1883). 



JafEna, Ceylon ('Ceylon Ob- 
fierver'). 

0£P Knria, north of Kingsmill 
Gronp, Eqnator, 172° E. (Mr. 
F. L. Clarke, in ' Honoluln 
Advertiser *). 

lia— 15°-2 S. 87°-3 B. ('Met. 
Zeitschrift'). 



OaroZa— ll°-2 N. 19°-9 W. 
('Met. Zeitschrift'). 

Queen of C7aw5ria— 14° 31' N. 
27° 2' W. (Met. Office Log). 

Pallai, Ceylon ('Ceylon Ob- 
server,' September 20, 1883). 



Colombo, Ceylon (' Ceylon Ob- 
server,' September 20). 



Jaffna, Ceylon (' Times of Cey- 
ko,' September 20). 



Date. 



Sept. 13. 

Sept. 13. 
Sept. 13. 

Sept. 13. 

Sept. 13. 

Sept. 13, 14. 
Sept. 14. 

Sept. 14. 

Sept. 14. 
Sept. 14. 
Sept. 14. 



Sept. 14. 



Sept. 13, 14. 



Notes. 



Still a yellow haze in the upper atmosphere, but 
less dense. 



Green sun. 
Bitse everywhere. 



" I don't know what to call the stuff that is seen in 
the upper regions, thin cirro-stratus or haze. 
It was like that seen south of the equator, first, 
early on September 1, and last on September 5." 

" Lately, besides the green sun, the weather has been 
abnormal ; very dense white and leaden coloured 
clouds." 

Bright-red glows from 7 to 7.16 p.m. 



Most brilliant sunset. Gorgeous hues. Rich 
crimson with bars of deep blue radiating from 
west. 



Half an honr before sunrise intense red glow. Sun 
rose as a pale greenish-ydlow disc. From 6.30 
to 7.15 p.m. lurid redness like distant conflagra- 
tion. 

The sun at 5^ before setting became light-green. 
Cloud stratum in west, uniform grey. 



Same sky haze as oil 13th. 
quite green when setting. 



The sun appeared 



The sun seems to have quite recovered his bright- 
ness, and all signs of the peculiar green or bluish 
appearance he presented a few days ago have 
vanished. For the last evening or two, however, 
a remarkable lurid glow, as from an immense 
conflagration, has been noticeable all over the 
western sky long after sunset. 

" Neither we nor any who have yet recorded their 
observations can remember the zodiacal light 
being coloured green. There was also the per- 
sistence of the colouring for three successive 
days,^ &c. 

At about 7 in the evening, the western part of the 
horizon was lit up by an unusual brilliant red: 
light. It lasted for about a quarter of an hour, 
and then gradually disappeared. 



2 P 



286 



THE HON. ROLLO RUSSELL 



Place. 



Date. 



Notes. 



Madras (Mr. Pogson, * Nature,* 
Angust 7, 1884). 

Madras (Mr. Pogson, * Nature/ 
August 7, 1884). 

Bhopal, India-23° N. IT E. 
C Nature,' April 24, 1884). 

South Australia (* Nature,* De- 
cember 20, 1883). 



Tasmania— 42^ S. 146° 46' E. 
('Met. Zeitschrift;' Mer- 
cury, Hobart Town). 

CaroZa^l4°-8 N.20°-8 W. (*Met. 
Zeitschrift'). • 

Frieda Qra'Trtpp—lT^ N. 27°'3 
W. (* Met. Zeitschrift '). 

Queen of Cambria — About 16° 
N. 27^ W. (Met. Office Log). 

Superb— \(f N. 146** W. (Met. 
Office Log). 

Barbadoes— 13° N. 69° 30' W. 
(Mr. Symons, 'Times* De- 
cember 6, 1883). 

South-east Australia, Port 
Augusta to Melbourne (Mr. 
Todd, * Nature,* December 
20, 1883). 

Thessalus—^l^" 29' S. 81° 46' E. 
(Met. Office Log). 

Frieda Qrampp—ir2 N. 27°-6 
W. ('Met. Zeitschrift'). 

Coppename-^2'' N. 39° 30' W. 
(Met. Office Log). 

ThepsoLus—^r 49' S. 82° 23' E. 
(Met. Office Log). 



Sttperb—About 12'' 12' N. 146° 
7' W. (Mr. Dove, MS. ; Cap- 
tain, Met. Office Log.) 



Sept. 14. 
Sept. 16. 



Sept., Oct., Nov., 
and early Dec. 

Sept. 16. 



Sept. 16. 

Sept. 16. 
Sept. 16. 
Sept. 16. 
Sept. 15. 
Sept. 16, 16. 

Sept. 16. 

Sept. 16. 
Sept. 16. 
Sept. 16. 
Sept. 17. 

Sept. 17. 



Sky golden-red till 6.50 p.m. 



In the west the colour was gulden to orange-yellow, 
in the east greenish. Bed clouds till 7.5 p.m. 



Very intense after-glows. 



From this date to the end of the month the twilight 
glows were seen. From September 18 ** aurora" 
after sunset. Duration abont 1 hour 36 minntes. 
Secondary appeared when primary was about 7** 
or 8° above horizon. 

Twilight phenomena "first seen. 



Corona round moon about 16°, red outside. 
Sun grass-green at rising and setting. 
Same peculiar haze. 
Halo 46° diameter. 
Sun various coloui's. 

From this date twilight phenomena. 



A remarkably fine sunset sky at 7 p.m., blood-red 
in west. A red haze round the moon all night. 

Sun and moon of a green tint at rising and setting. 



Halo round moon 8 p.m. 



The sky, half an hour before sunrise, had a singular 
appearance, assuming a very unnatural and 
appalling colour. 

Sun like a green ball when rising, and continued so 
for some time; moon also green. Thin cirro- 
stratus. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



287 



Place. 



Date. 



Notes. 



Borghese—2y' W N., 18^41' W. 
(Met. Office Log). 

Colombo, Ceylon 



New South Wales 

Barghege^ir N. 21° W. (Met. 
Office Log). 

jffqpe— 24'' N. 140° 5' W. (Cap- 
tain Penhallow, * Nature/ De- 
cember 20). 



Superb— (Ur, Dove, MS.) 



^ i8«£cr6 (Captain)— 16° N. 147^= 
W. (Met. Office Log). 

iS«per6— About 19° N. 150° W. 
L (Mr. Dove, MS.) 

Cape of Good Hope 

Graaf Reinet, Tranavaal— 32° 
16' S. 24° 63' E. (Mr. Carey 
Hobson, 'Nature,' November 
29, 1883). 

/<wo»— 49*'-9 S. 489W. ('Met. 
Zeits.'). 

Emma Earner— M°'9 S. 22°-4 E. 
('Met. Zeitschrift'). 

Cbelsea, London— 51** 32' N. 
(Mr. Ascroft, MS.) 

Superb (Captain)— 22** N. 150° 
W. (Met. Office Log). 

Thessalus—lS'* S. 82° 46' E. 
(Met. Office Log). 

Cojypennme-^9'' N. 20° 16' W. 
(Met. Office Log). 

Umballa— 30° 30' N. 76° 30' E. 
(*Met. Zeitscbrift'). 

Santiago, Chili ('Met. Zeit- 
scbrift*). 



Sept. 17. 
Sept. 17. 

Sept. 18. 
Sept. 18. 

Sept. 18. 
Sept. 18. 

Sept. 18. 

Sept. 19, 20. 

Sept. 20. 
About Sept. 20. 

Sept. 20. 
Sept. 20. 
Sept. 20. 
Sept. 21. 
Sept. 21. 
Sept. 21. 
Sept. 21 to 30. 



Sept. 21 to 30, and 
previously. 



Sky luminous about 6 p.m. 

Magnificent sunset. Warm red colours. Apparently 
too bright and long-continued to be due to any- 
thing short of the zodiacal light. Later the 
atmosphere looked greeu. 

From this date aurora after sunset. 

Sky luminous about 6 p.m. 



Fine twilight glows. 



Rose at 6 a.m. to see the green sun, but it had ^ne 
behind clouds, through which the green sunlight 
was visible. Peculiar brass-coloured clouds in 
west at sunset. 

High thin stratus. 



Beautiful sunsets. Long narrow clouds like wrinkles 
in the sky. 

Twilight glows first generally observed. 

Prolonged lurid light 1 hour. Glows began to be 
noticed. 



After sunset strange appearance of the sky in west ; 
all hues of red ; in east yellowish-green or blue. 

Red sky long after sunset. 



After-glow, first undoubted appearance of peculiar 
glow. 

Beautiful parallel streaks of cirro-cumulus on 
north-western horizon. 

From half an hour past sunset to past 7 o'clock the 
sky in south-west was red like ^* aurora borealis." 

At 6 a.m. upper sky red, then orange tinged with 
green. 

Splendid glows. 



Twilight glows. 



2 P 2 



288 



THE HON. ROLLO RUSSELL 



Place. 



Date. 



NOTKB. 



North Pacific (Mr. Bishop) . . ! Before Sept. 22. 



Madras (Mr. Pogson, * Nature,' 
August 7, 1884). 

Lunugala, Ceylon (* Ceylon Ob- 
server'). 

Colombo (' Ceylon Observer '). . 
Ceylon (Ceylon newspapers) . . 



Mannir, Ceylon (* Ceylon Ob- 
server'). 

10" 48' N. 78^ 52' E. (A. T. F., 
* Ceylon Observer,* October 
25). 

Hawaii (Rev. S. E. Bishop) . . 

Madras (Mr. Pogson, * Nature,' 
Aufpist 7, 1884). 

Colombo (* Ceylon Observer '). . 



Mann^, Ceylon (*Ceybn Ob« 
server *). 

Lyttelton—^SV S. 39° 56' W. 
(Met. Office Log). 

8tiperh--2ff' 29' N. 147° 52' W. 
(Met. Office Log). 

Ceylon (Mr. H. Parker, MS.) . . 



ThessaJut-A'' S.83* 9' B. (Met. 
Office Log). 

Duem— 14° N. 32° 30' B. (Hicks 
Pasha, * Times,' December 
14). 

Ireland (* Met. Zeitschrift ') . . 



Reunion— 21° S. 55° 30' E. 



Sept. 22. 

Sept. 22. 

Sept. 22. 
Sept. 22. 

Sept. 22. 

Sept. 22. 

Sept 22. 
Sept. 23. 

Sept. 23. 
Sept. 23. 
Sept. 23. 
Sept. 24. 
Sept. 24. 



Sept. 24. 
Sept. 24. 



Sept. 24 and fol- 
lowing days. 

Sept. 25. 



Traders to Honolulu had noticed the haze, Ac^ a 
considerable time before September 22. 

Suu rose as a yellow ball, and showed distinct 
greenish-yellow afterwards. 

Sun like moon at 7 a.m. 



Ghreen sun returned evening of 22nd. 

Qreen sun returned. At Jaffna first seen again on 

2l8t. 

Sun pale green in the evening. 



Sun's disk of a hue in which green predominated. 



Renewal of glows. 
Sun rose very green. 



At 2 a.m. moon dull and green coloured. Sun rose 
dull and rayless, with a tinge of green. 

Sun pale green on rising. In setting left only a 
greenish instead of golden light in the sky. 

Sky has a peculiar fiery appearance, as of a large 
fire behind the bank of clouds. 

CiiTo-cumulus arranged in lines from S.S.W.^W. 
to N.N.E.^E. ; a perfect cirro-cumulnii. 

Green appearance in sky similar to that of Septem- 
ber 9 and 10, but not so vivid ; snn's disc defined, 
and greenish-yellow; sky around it yellowish- 
green. Sky hazy. Just after sunset leaden-blne 
till half an hour after; orange in west. Broad 
distinct palish streaks pointing west. 

Yellow sky to east at 8 a.m. 



Sun rose green. 



First appearance of after-glows. 



From this date continuously magnificent glows. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA, 



239 



Place. 



Datk. 



Notes. 



bcLghalie — K. Georgo's Sound 
to north of Boarbon (Flam- 
marion). 

Sco^ta— 36° N. 4° W. (Met. 
Office Log). 

Haslemere, Sarrey (Hon. R. 
Russell, MS.) 

Ceylon (* Times* of Ceylon, 
September 28, 1883). 



/Jar-2?°-9 S. 46°-3 E. ('Met. 
Zeitschrift'). 

Kurracbee (Mr. P. C. Constable, 
' Nature,' November 15, 1883). 

OZ5er*-9° S. 35° W. (Met. Office 
Log). 

H.M S. Magpie^ Labuan, Captain 
Vereker (Met. Office Log). 

Olher^-'b'' 13' S. 35° W. (Met. 
Office Log). 

0Z6er« — 2° S. 38' W. (Met. 
Office Log). 

Brazil, locality not stated 

Rio de Janeiro (M. Cruls, 
* Comptes Rendus,' April 21, 
1884). 

Areqnipa ('Met. Zeitschrift').. 

Buenos Ayres (M. Beuf , 'Comptes 
Rendns,' Febraary 25, 1884). 

Somerset, Mass. U.S. (S. S. R.) 

0lber9—r 23' N. 41° 6' W. (Met. 
Office Log). 

Poochow (Father Dechevrens, 

Shanghai— 31° 14' N. 121° 27' E. 
(Father Dechevrens, *N. China 
Daily News '). 



Sept. 26 to Oct. 
12. 



Sept. 26. 

Sept. 26, 27. 

Sept. 27. 



Sept. 27. 

Sept. 28. 

Sept. 28. 

Sept. 29. 

Sept. 29. 

Sept. 30. 

Sept. 30. 
End of Sept. 

Last days of Sept. 
Last days of Sept. 

Sept. and Oct. 
Oct. I. 

Early in Oct. 

Beginning of Oct. 



Remarkable sunsets. 



8 a.m., hazy rouud horizon. Zodiacal light at 7.2G 
p.m. 

Light pink cirrus stripes at sunset. 



" Yesterday morning, when the sun rose a little 
above the horizon, it looked very beautiful, being 
of a soft greenish tint, and as it set, instead of the 
golden streaks it leaves behind, we fiaw only a 
sort of greenish light. It still continues the 
same." 

Sky exactly as on September 14 (see p. 285). 



From this date red glow after sunset, greenish sky 
and green moon. 

Sun set pale blue. 



A yellow coloured fine-looking sky at snnset. 



Sun whitish appearance 5.30 p.m. 



Sunset bright amber. 



Red sunsets begfan. 

The glows began about this time, but the glow then 
was of short duration, and the sun set rayless in 
a misty stratum. 

Very strong glows, as never before seen. 

The glows began. They lasted 1 hr. 30 min. The 
sun and moon were ocoanonally oolonred. 

Beautiful sunsets. 
Sunrise very pale. 



Fiery skies. Taken at first for a conflagration. 



Fiery skies. From first days of October to Decem- 
ber 16th intense red in western sky. 



290 



THE HON. ROLLO RUSSELL 



Place. 


Date. 


Notes. 


Onwa-18° 17' N. 86^ 44' E. 
(Met. Office Log), 


Oct. 2. 


Red glare or halo round sun at noon, 25" to 30° 
diameter. 


Honolulu (Rev. S. E. Bishop, 
'Nature,' April 10, 1884). 


October. 


Glow continued remarkable, but extremely un- 
equal. 


Bhopal, India— 23° 30' N. 77° 
30' B. (* Nature,' April 24, 
1884). 


October. 


Fine glows continued. Observed in September, 
October, November, and part of December. Partial 
return in March. 


Ja«mr-25°-7 S. 29°-5 W. ('Met. 
Zeitachrift'). 


Oct. 2. 


Strong glow to 1 hour after sunset. 


Arabia •• 


Oct. 1 to 14. 


Remarkable glows. 


Mauritius (Dr. Meldrum, * Proc. 
Met. Soc. of Mauritius,* Ac.) 


During October. 


Prolonged and intense glows lasting 1 hoar 15 
minutes. At Reunion magnificent glows. 


Canary Isles— 28° 30' N. 16° W. 


Oct. 1 to 10. 


Glows. 


Gulf of Mexico . . 


Throughout Oct. 


Splendid glows. 


Yucatan (Met. * Zeitachrift,' 
March, 1884). 


All through Oct. 


Twilight phenomena continued. 


Haslemere, Surrey (Hon. B. 
Bussell). 


Oct. 3. 


Red and yellow sunset. 


St EtZia— 29° N. 27° W. (Met. 
Office Log) 


Oct. 4. 


A.t 8 a.m., sky covered with cirro-stratus ; sky aloft 
pale yellow at 6 p.m. ; new moon quite green. 


/a«o»— 24°-3 S. 29°1 W. ('Met. 
Zeitschrift'). 


Oct. 4. 


Strong glow to 7.30 p.m. 


Thes8alus-'IS° 30' N.89° 11' E. 
(Met. Office Log). 


Oct. 4. 


Sky yellow near sun. 


Tirginia, U.S.A. (S. S. R.). . . 


Oct. 5, 
and later. 


Pine glows. 


Somerset, Mass., U.S.A. ('Met. 
Zeitschrift,' March, 1884). 


Oct. 5, 
and later. 


Magnificent and frequent glows. 


Carrizal Bay (about 300 English 
miles N. of Valparaiso)— 29° 
S. 72° W. 


Oct. 5. 


Red sunsets began. 


Nashville, Tennessee, U.S.A. 
(S. S. R.). 


Oct. 7. 


Sunset shadows very bright. 


Buenos Ayres and Monte Video 
—34° 39' S. 68° 23' W. (* Met. 
Zeitschrift '). 


Oct. 7,8. 


Very vivid sunsets. 


8t ffiWo— 23° 26',N. 33° 15' W. 
(Met. Office Log). 


Oct. 7. 


At 7 a.m., clouds above and below the sun of the 
colour of fire rust (sic), the sides of the snn 
quite white. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA 



291 



Place. 



Date. 



Notes. 



8t. XiWa— 23" N. 34° W. (Met. 
Office Log). 

Pensacola, Florida (' Met. Zeit- 
8chrift;'S. S. R.). 



Binninag, 40 English miles from 
Almorab— 29^ 30' N. 80° B. 
(MS.). 

Glencaim—W S. 84° E. (Met. 
Office Log). 



Thessalm—lff' N. 90° 60' E. 
(Met. Office Log). 

Hankow, China (Mr. Mac- 
Gowan, *E[nowledge/ March 
21, 1884) 

Swatow— 23° N. 117° B. (MS. 
from Lighthouse). 

Hobart, Tasmania 

Cape of Good Hope— 34° S. 18"^ 
30' E. (' Met. Zeitschrift'). 

China Seas (MS.) 



St. Eilda^Ahont 20° N. 37° W. 
(Met. Office Log). 

fifcAtZZer— 9°-5 S. 24°-3 W. 
('Met. Zeitschrift'). 

ScAiZZer— 6°-9 S. 24°1 W. 

Perth, W. Australia (*Met. 
Zeitschrift'). 

Hambantota, Ceylon (Mr. 
Parker, MS.) 



Sunbeam — Near Canary Islands 
(Lady Brassey, *The Roar- 
ing Forties *). 

Knrrachee ('Knowledge,' No- 
vember 23, 1883). 

Santa Barbara, California— 34'^ 
27' N. 119° 50' W. (Rev. 
S. E. Bishop, MS., Ac.) 



Oct. 8. 
Oct. 8, 9. 

Oct. 8, 9. 

Oct. 8. 

Oct. 9. 
Oct. 9. 

Early in Oct. 

Early in Oct. 
October. 

October and No- 
vember. 

Oct. 10. 
Oct. 10. 

Oct. 11, 12. 
Oct. 11 to 20. 

Oct. 11. 

Oct. 11. 

Oct. 14. 
Oct. 14. 



Sky as on 7th. 



First red twilights, snnrise and sunset. Magnifi- 
cent. Red up to zenith, appearance of a vast 
fire. 

Red and fiery after-glow till 7.20 p.m. 



Very peculiar appearance of the sky in the S.W. ; 
like reflection of a large conflagration, 34° south 
of sunset at 7 p.m. 

Sky very yellow near sun ; at 6.30 p.m., sky in 
W.N.W. soft fine red. 

After-glows began about this time. 



Brilliant glow about three quarters of an hour. ' 

Magnificent sunsets. October 12 fine after-glow. 
Magnificent glows continued. 

Glows observed by pilots. 

Sky as on 7th. 

Cloudless sky, fiery air. 

Cloudless sky, fiery air. 
Twilight glows. 

Haziness still remaining, and greenish sky. 



Indescribably splendid sunset. Sky coloured 
purple, orange, yellow, green, and blue. 



Brilliant glow after sunset. 



Fine after-glow. 



292 



THE HON. HOLLO RUSSELL 



Place. 



Orissa—ir ST N. 82° 67' E. 
(Met. OfBce Log). 

Montgomery, Alabama, XT.S.A. 
-32°21'N. 86 23'W. CMet 
Zeitechrift'). 

Drenthe—lS'' 36' N. 39° W E. 
(Ship's Log). 

Nice— 43° 42' N. 7° 16' E. 
(* Knowledge/ December 7, 
1883). 

Lisbon— 38° 41' N. 9° 10' W. 
(Captain de B. Capello, Obser- 
vatory, * Standard,* and MS.) 

TenerifEe— 28" 26' N. 16° 40' W. 
C Times '). 

Om«o— 8°42' N. 82° 60' E. (Met. 
Office Log). 

GZeri^aim— 13° 34' S. 91°32'E. 
(Met. Office Log). 

Oakwood, San Diego Co., Cali- 
fornia (S. S. R.). 

Yuma— Abont 33° N. 116° W. 
(Signal Service Report). 



Batavia •• 

Port Elizabeth, Natal (MS.) 



Mhow, Knrrachee~24° N. 68" 
E. (MS.) 

Chelsea, London (Mr. Ascroft, 
MS.). 

Haslemere, Surrey (Hon. R. 
Russell). 



Umballa-50° 30' N. 76'' 30' 
E. ('Nature,' December 13, 
1883). 

Santiago, Chili (*Met. Zeit- 
schrift *). 

Haslemere, Surrey (Hon. R. 
Rusfleirs Register). 



Date. 



Oct. 14. 
Oct. 15. 

Oct. 15. 
About Oct. 15. 

Oct. 16 to 24. 

About Oct. 

Oct. 16. 

Oct. 17. 

Oct. 19. 

Oct. 19 and 20. 

Oct. 20. 

Before and on 
Oct. 20. 

Before and on 
Oct. 20. 

Oct. 20. 
Oct. 20. 



Some time before 
Oct. 20. 



Oct. 21 to 31. 



Oct. 21. 



NOT«S. 



From 8 p.m. to midnight, circle round moon 4h° m 
diameter. 

Vivid after-glow. On October 14 very peculiar 
appearance in western sky. 



Remarkable yellowish sky after sunset. 



Extraordinarily beautiful sunsets and kmg glow. 



Remarkable sunsets with after-glows. Maximnm 
October 18. White apparent cirms or cirro- 
stratus visible after sunset. 

Glows lasted 1 hour. Sunrise light like fire. 



At sunrise ugly looking sky, brick*red under sob 
to 20'' altitude. 

Very broad dark-reddish or copper colour ring 
round moon. 

First twilight phenomena.^ On October 18 wbito 
ring round sun. 

Sky beautifully red 1^ hours after sunset. 



Fiery light in west. 
Heavens aflame nightly. 

Very brilliant glows, chiefly greenish. 

After-glow prolonged. 

Fine reddish sunset, with bright isolated cloud, aii^ 
slight low cirrus. High cirro-stratus or some- 
thing similar. 

Fine glows. 



Twilight glows continued. 



Fine reddish and orange sunset. 



ON THE FIRST APPEARAJ^OES OP OPTICAL PHENOMENA. 



293 



Place. 


Date. 


Notes. 


Yuma, Arizona, Tr.8.A. — About 
32^ 45' N. 114** 38' W. 
(S. S. R.)- 


Oct. 21. 


Blood-red sky till 1^ hour after sunset. 


Haslemere, Surrey (Hon. R. 
Kusseirs Eeglster). 


Oct. 22. 


Sun set in " bath " of cirrus. Halo effect, red ; rest 
of sky dear. 


Haslemere, Surrey (Hon. R, 
Rnsseirs Register). 


Oct. 23. 


Sun set in clear sky, but white mistiness on horizon. 


Santos, Brazil (The Consul, 
MS.) 


From about Oct, 
22. 


Glows. 


Fort Grant, Ai-izona (S, S. R.), 


Oct. 23, 


Magnificent and peculiar sunset. 


Kangra Valley— 32" N. 76° E. . 


Oct. 24. 


Curious glow like aurora long after sunset. 


Kuagin — Woosung, China (Cap- 
tain AndersoD, MS.) 


Oct, 26. 


Most extraordinary sunset. Sun set white and 
without power in the midst of an arch of intense 
red. The red arch reached to 30° or 35°. Similar 
sunsets October 31 and November 2 and 7. 


Iqnique— 20** 10' S. 70° 7' W. 
(•Met. Zeitschrift'). 


Oct. 25, 


Sunset 6.15. ; splendid glow till 7.20 p.m. 


Shanghai— 31° 14' N. 121° 27' 
E. (MS.) 


Oct 26. 


White sun, red arch, various hues, milky-white 
stratum. Appearance of a raging fire. 


Orontes — Just south of Equator, 
off W. African coast (Lieut. 
Hope, * Nature,' December 
13, 1883). 


Oct. 25. 


Splendid glow in S.W., red till 8 p.m. 


Lanzarote, Canary Islands — 
About 29° N. 14° W. (Mr. 
Buchanan, * Times,' Decem- 
ber 25). 


Oct. 27. 


Splendid glows. 


Haslemere, Surrey (Hon. R. 
Russell's Register). 


Oct. 27. 


Some streaks of soft delicate cirrus in irregular 
patches, turning fine pink at sunset. Glow from 
horizon. 


Mauritius(Dr.Meldrum,MS . and 
*Proc.Met.Soc.of Mauritias *). 


Aug. 28 to Oct, 
27. 


Extraordinary sunsets. 


Wellington, Kansas (* Met. 
Zeitschrift'). 


Oct. 28. 


Bright red sunset. 


NashviUe (Tenn.) (S. S, R.) . . 


Oct. 29, 


Magnificent sunset. Red till 6.40. 


Sun Diego, California (S, S. R.). 


Oct. 30, 


Brilliant reflection in western sky. 


Eastern States of N. America 
(Signal Service Report). 


Oct. 30, 


Fine sunsets began. 


Nashville (Tenn.), Atlanta 
(Georgia),Charlotte (N.Caro- 
lina), Lynchburg (Virginia), 
Memphis (Tenn.) (S. S. R.). 


Oct, 30, 


Beautiful sunset. " Like a vast fire " at Charlotte. 
Lasting more than 1 hour at Memphis. 



2 Q 



294 



THE HON. ROLLO RUSSELL 



Place. 


Date. 


Notes. 


Kamptee, Madras (* Knowledge,' 
November 30, 1883). 


Oct. 30. 


The extraordinary glows have continued, nearly 
every evening. After the sky got dark, it 
g^dually re-assumed the most brilliant roseate 
hues. Also son used to be green in the morning. 


Memphis, Tennessee, U.S. (Sig- 
nal Service Report). 


Oct. 29, 30, 31. 


Glows. 


Atlanta (Georgia), Stafebnrg 
(S. Carolina), Lynchburg 
(Virginia), (S. S. R.). 


Oct. 80, 31. 


Brilliant red sunsets. At Lynchburg rosy glow np 


Santos, Brazil (Consnl, MS.) . . 


End of Oct. 


Glows. Red glare. 


Belfast^Sr 21' S. 13° 16' E. 
(Met. Office Log). 


Oct. 31. 


Zodiacal light till 9 p.m. 


Roscommon, Ireland (A. C, 
' Nature,' February 21, 1884). 


End of Oct. 


Glows after sunset. All phenomena as observed by 
Prof. Divers in Japan. 


Honolulu (Rev. S. E. Bishop, 
* Nature,' April 10, 1884). 


Nov. 


Great abatement of the glows during this month. 


Sydney, N.S.W. (Mr. Har- 
gi-ave, MS.) 


Nov. 1. 


Sunset 6.25. First phase 6.40. Deep crimson near 
horizon 7.10. Streaky white above crimsi.ii. 
Second glow began 7.12. Pink nearly gone 7.45. 


Kailong, Lahoul — About 32" 
40' N. 77° E. (MS.) 


Nov. L 


Sheen round sun about 80° diameter. Glows began. 
Sun could be looked at at midday. 


Roy. Observatory, Greenwich 
(* Standard,' December 26, 
1883). 


Nov. 2. 


Brilliant sunset. 


Somerset, Bristol Co., U.S. 
C Zeits. fiir Met.'). 


Nov. 3. 


Splendid glows. Also on lltb, 13th, 26th, and 2rth. 


Eo^aWo— 2** to 13° S. 33° to 36° 
W. OMet. Zeitschrift'). 


Nov 5 to 8. 


Hazy air. 


Vester Torslev, Denmark (MS.) 


Nov. 5 to 12. 


First glow observed. 


Sunbeam — Gulf of Paria, Vene- 
zuela (Lady Brassey, * Roar- 
ing Foi'ties '). 


Nov. 4. 


Sunrise marvellously fine. 


Haslemere, Surrey (Hon. R. 
Russell's Register). 


Nov. 8. 


" Fine sunset with straight lines of cirrus (?) and 
very slight bank. Long after sunset and till nearly 
dark a pink glow from some very high filmy 
cirrus." 


Maresfield, Sussex (* Know- 
ledge,* November 30, Captain 
Noble). 


Nov. 8. 


Glow observed. 


Greenwich (* Nature,' January 
31, 1884, Mr. Ellis). 


Nov. 8, 9, Ac. 


Glows. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



295 



Place. 



Date. 



Forsyth, Monroe Co., Georgia, 
U.S. (Signal Service Report). 

On the Volga ('Met. Zeit- 
schrift'). 

Nelson Co., Virginia, U.S. (Sig- 
nal Service Report). 

Haslemere, Surrey (Hon. R. 
Rnssell's Register). 



Notes. 



Sudbniy, Suffolk (Dr. H. Aiiy 
in 'Nature,' November 29, 
1883). 

Cape of Qood Hope (* Met. 
Zeitschrift '). 

Laconia, Harrison Co., Indiana 
(Signal Service Report). 

Sussex, Kent, Suffolk, Mid- 
dlesex, Worcester, Isle of 
Wight, Oxfordshire (* Daily 
Chronicle,' November 10). 

Babbacombe, Devonshire (Mr. 
Glyde). 

Haslemere, Surrey (Hon. R. 
RusselFs Register). 



Minnesota, New Garden, N. 
CaroHna, and other places in 
the U.S. (* Met. Zeitschrift '). 

Ber<^-45°-5 N. 24^2 W. 
('Met. Zeitschrift'). 

Dublin 



Nov. 

About Nov, 8. 
Nov. 

Nov. 9. 



Nov. 9. 

From Nov. 9. 

Nov. 9 to 30. 

Nov. 9. 

Nov. 9. 
Nov. 10. 



Nov. 10. 



Nov. 10. 



Nov. 11. 



Throughout the month beautiful sky before and 
after sunset. Like aurora on 29th. 



Glow seen. 



Glow nearly every fair day during the month. Max. 
27th and 28th. 

At 8 a.m. detached cirrus, cirro-cumulus, and cirro- 
stratus moving fast from W.S.W. At 9 a.m., 
series of rippled cirrus in web-like uncrossed 
BtrisB moving transversely. At 7.30 a.m. some 
high pink filmy cirras (?) like last night. At 
11.20 a.m. blue sky, but some large patches of very 
high cirro-cumulus, one overhead in very small 
fleeces and partly in re-curved waves or bars. 
Light of the sun in setting peculiarly yellow, with 
slight bank of haze. Sky clear and blue. At 
15 minutes after sunset extraordinary red, green » 
yellow, and white opalescence. Very strong red 
glow, lasting 1 hour and 40 minutes after sunset, 
from an apparently motionless film. 

Glow seen. 



Glows continued fine. 



Very brilliant sunrises and sunsets. 



Strong and long-continued red glow after sanset 
Described as ** aurora " at Dover, and " very like 
aurora" at Oxford. At Worcester, like " a great 
conflagration." 

Yery fine rosy glow after sunset. 



At 6.20 a.m. pink sunrise light in the east. About 
3.30 p.m., on close scrutiny of the clear sky, a 
very thin high rippled haze visible in parts. About 
4.32, 14 minutes after sunset, a small portion in 
the west began to glow, and lasted bright pmk 
till 5.10. 

Splendid sunset. 



Light red mist in west about sucset. 



Sky brilliant with cirras. 



2 Q 2 



296 



THE HON. ROLLO RUSSELL 



Place. 


Date. 


Notes. 


Simbirsk— 54° N. 48^ B. (* Met. 
Zeitschrift '). 


Nov. 11. 


Fine glows. 


Amarapoora-^IO^ 16' N. 86" 34' 
E. (Met. Office Log). 


Nov. 12. 


Very peculiar appearance in sky, m if the upper 
cirrus full of fine yellow sand, night and day. 


Switzerland (Professor Forel, 
* Comptes Rendufl '). 


Nov. 11 to 21. 


Corona round sun between these dates. 


Le^zig^2S° N. IS^'S W. C Met. 
Zeitschrift'). 


Nov. 12, 13. 


Strong after-glow. 


Bojal Obserratorj, Greenvich 


Nov. 13. 


Clouds in N.W. tinged with crimBon from 3 p.m. to 
sunset. 


Salina, Kansas— 38^ N. 97° W. 
C Met Zeitschrift'). 


Nov. 14. 


Glows first seen. 


Florida (S. S. R.) 


Nov. 15. 


Glows began again. 


Lom8viUe-33* 16' N. 86^ W. 
(Signal Service Report). 


Nov, 15. 


Glow first seen. 


Wellington, Snmner Co., Kan- 
sas (Signal Service Report). 


Nov. 15 to 30. 


Before sunrise a red or orange band, then yellow, 
and afterwards green sone. 


Lonisville, Kentncky (S. S. R.). 


Nov. 16 to 30. 


Glows. 


Carson, Armstrong Co., Nevada 
(Signal Service Report). 


Nov. 18 to 80. 


Glows. 


Berkeley, California (ProL J. 
Le Conte, ' Nature,' February 
28, 1884). 


Middle of Nov. 


First glows. Striking on November 24, when at 
6 p.m. the sky had the appearance of a ooa- 
flagration. Glare round sun« 


H«nkow,China(* Nature,' March 
6, 1884). 


Nov. 17. 


Green sun and afler-glows. 


Redhill, Surrey (MS.) . . 


Nov. 16. 


Glow after sunset. 


TwcedftfoZfl— 10°-8 N. 86°-3 E. . . 


Nov. 16, 17. 


Sky all day near sun has a peculiar reddish tint. 
Moon the same on 13th and 14th. 


Malaga, Spain • • 


Middle of Nov, 


Glows splendid from this time. 


Haslemere, Surrey (Hon. R. 
Russell). 


Nov. 17, 18. 


Fine sunrise. Deep red and bright yellow. 


Flateyrr, extreme N.W. of Ice- 
land (MS.) 


Nov. 17. 


Colour of clouds brown-red. Fine sunset On 
November 18 clouds brown. 


Nevada— 37° N. 117° W. Q Met. 
Zeitschrift'). 


Nov. 18. 


Glow first seen; continued till 30<h. 


Provence, France (M. Gasparin, 
* Comptes Rendus,' February 
21,1884). 


Nov. 19. 


Fine after-glows from this date to January 24, 1884. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



297 



Place. 


Date. 


Notes. 


Colorado College (Prof. G. H. 
Stone, * Nature,' Pebroary 28, 
1884). 


Noy. 


Soon after middle of November glows and corona. 


Auburn, Lee Co., Alabama 
(Signal Service Report). 


Noy. 20 to 27. 


The week has been characterised by wonderfully 
brilliant sunsets. 


Haslemere, Surrey (Hon. B. 
RuBsell). 


Noy. 19. 


Pine sunrise. Deep red turning to yellow. W hite 
mist. 


Toronto (MS. and printed Re- 
port). 


Noy. 20. 


Glows began. Splendid November 22. 


Constantinople (Dr. Budde, 
'Nature,' December 20, 1883). 


Noy. 20. 


Glow first seen. 


Tambow, Russia (MS.) . . 


Nov. 20, 21. 


Glow first seen. 


Baltimore, U.S. (Mr. W. Num- 
sen, * Knowledge,' January 4, 
1884). 


About Noy. 20. 


Appearance of a tremendous fire along the horizon, 
and to an altitude of 40**. Disappeared a little 
before 7 p.m. 


Prague (Brauner, ' Nature,* 
January 3, 1884). 


Noy. 22. 


Sunset 4.30. Glow as of a great fire at 5 ; disap- 
peared about 5.30 p.m. 


Castasegna, Switzerland (* Met. 
Zeitschrift '). 


Noy. 22. 


Strong morning glow. 


London, Canada (MS. Report) 


Noy. .22. 


Most extraordinary sunset. Pitch dark in E. and 
zenith, a blaze of red lurid fire in W. 


TTpsala (Hildebrandsson, ' Stan- 
dard,' December 26, 1883). 


Noy. 22. 


Splendid rosy tint over western sky, and yellowish- 
green in N.E. and N. Duration 2 hours. 


Nedanocz, Neu tra-tbal,HungaT7 
C Zeitschrift fiir Met.'). 


Noy. 22. 


Very bright glow at 6 a.m. ; supposed to be a great 
fire. 


Oregon (* Met. Zeitschrift ') . . 


Noy. 23 to 30. 


Fine twilight glows. Began at 6 a.m. In evening 
lasted till 6.45 pjn. 


Missouri, U.S. ('Met. Zeit- 
schrift')- 


Noy. 23. 


Glows observed generally. At St. Louis, 2 hourer 
before sunrise and after sunset, sky red from 
horizon to beyond zenith. 


Canada (MS., Ac.) .. .. 


Noy. 23. 


Earliest glows in many places. 


L' Original, Canada 


Noy. 23. 


Glows. Sunset very red. 


Victoria, British Columbia 
(Rey. — Jenns, MS.). 


Noy. 23. 


Most magnificent glows this day, as if country ablaze 
with flame. Their duration was 2 hours. 


New Westminster, British Co- 
lumbia (Captain Peele, MS.) 


Noy. 28. 


Glows seen. Sun set in cloudless bright-yellow 
sky. After a few minutes red and yellow arch. 
Maximum 1^ hour after sunset. Duration about 
2 hours. Second glow passed the zenith 1^ hour 
after sunset. 



298 



THE HON. ROLLO RUSSELL 



Place. 


Date, 


Notes. 


Alabama, California, Humboldt 
Co. Colorado, Connecticnt, 
Dakota, Florida, Georgia, 
Illinois, Indiana, Iowa, Dela- 
ware, Kansas, Kentucky, 
Maine, Massachusetts, Michi- 
gan, Missouri, Nebraska, 
Nevada, New Hampshire, 
New York, N. Carolina, Ohio, 
Pennsylvania, Texas, Vir- 
ginia, Washington, Wisconsin, 
Mississippi (S. S. B). 


Nov. 23, 24. 


From this date morning and evening glows. Thej 
began in the Northern States about November 
21, and were brightest on November 27, 28, and 
29. 


San Francisco (Rev. S. E. 
Bishop, * Nature,* January 
17, 1884). 


Nov. 23, 24. 


Glows first Been. 


Reykjavik, Iceland (M. Trom- 
holdt, * Nature,' February 
28, 1884). 


Nov. 23. 


Purple sky between 6 and 6 p.m. 


Bamberg, Germany (* Met. Zeit- 
schrift *). 


Nov. 23. 


Morning glow. 


Richmond, Surrey (Hon. R. 
Russell). 


Nov. 23, 24. 


On 23rd sun set in cirro-stratus or cirrus-striiB. On 
24th sun set in misty strieB, turning yellowish- 
green after sunset. Sun disappeared several 
degrees above horizon. 


Gravenhur8tr-44° N. 79° W. . . 


Nov. 24. 


Glow seen. Brilliant crimson in sky at sunrise and 
sunset. 


Flateyrr, N.W. Iceland (MS.). . 


Nov. 24. 


At 9.30 a.m. violet sky. Yellow and green clonda. 


York and Sunderland (Mr. J. E. 
Clark, * Nature,' December 6 ; 
Mr. T. W. Backhoase,'Nature,' 
January 10, and MS.). 


Nov. 24. 


First fine sunset. Pink circle round sun distinctly 
seen November 26. 


Bray, Wicklow (' Nature,' De- 
cember 13, 1883). 


Nov. 24. 


First glow. 


Berkeley, California (Prof. J. 
Le Conte, ' Nature,' February 
28, 1884). 


Nov. 24. 


Striking after-glow. At 6 p.m. appearance of a 
great fire. Glare round sun. 


S^nfeeaw— 30° 3'N. 77° 28' W. 
(Lady Brassey, ' Roaring 
Forties '). 


Nov. 24. 


Most splendid sunset. Orange and scarlet after- 
glow, like aurora, over the sky. 


Tatoosh Island, Washington Ter- 
ritory (Signal Service Report) . 


Nov. 24. 


Glow 2 hours after sunset. 


St. George's, Delaware, U.S. 
(Signal Service Report). 


Nov. 24. 


Glows began and lasted through December. 


Monticelli, Jones Co., U.S. (Sig- 
nal Service Repoi't). 


Nov. and Dec. 


Glows. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



299 



Place. 



Oakwood, San Diego Co., Cali- 
fornia (Signal Service Re- 
port). 

Hjdesville, Humboldt Co., Cali- 
fornia (Signal Service Re- 
port). 



Oakland, Alameda Co., Cali- 
fornia (Signal Service Re- 
port). 



Lindsay, Canada— ^4° N. 78° 
W. (MS. Report). 

Hamilton— 43° N., 80° W. (MS. 
Report). 

Beatrice-^'' & N. 79' 20' W. 
(MS. Report). 



Honolulu. 



Lisbon, Portt^l (Captain De B. 
Capello, MS. and ' Standard ') . 

Luneville, France 

Naples (Padre Denza, ' Nature,' 
Dec 20, 18S3). 

Italy, Alps to Calabria (Padre 
Denza, ' Met. Zeitscbrif t '). 

Ashby Parva, Lutterwortb 
(Miss Annie Ley, 'Nature,' 
Nov. 29, 1883). 

Dover (* Daily Cbronicle,' Nov. 
26). 

Royston, Herts (Rev. C. Miles, 
MS.) 

Lichfield ; Saltbum ; Hunstan- 
ton ; Skegness (' Standard '). 

Lichfield (Mrs. Chawner, MS.) 



Dati. 



Nov. 24. 



Nov. 24 to 30. 



Nov. 26. 



Nov. 25 (about). 

Nov. 25, 26. 

End of Nov. 

Nov. 25. 

Nov. 25. 

Nov. 25 to Dec. 2. 
Nov. 25. 

Nov. 25 to Dec. 1. 

Nov. 25. 

Nov. 25. 

Nov. 25. 

Nov. 25. 

Nov. 25 and 29. 



Notes. 



Sun surrounded by whitish glare during day. Sun- 
set displays from November 24 to 30 as on 
October 18. 

Very brilliant twilights, morning and evening. Sky 
became red about 1 or 1^ hour before sunrise, 
and gradually faded. Just after sunset the sky 
began to grow red and continued increasing in 
brilliancy for about 1 hour. On 24th like a great 
fire in south. 

In the morning a luminous silvery twilight ; as the 
sun came up the light rose nearer to the zenith^ 
changing to a reddish-pink and forming a cres- 
cent, beneath which was a pale green colour of an 
apparent diameter of 60°. As sun rose the colout 
changed to yellowish -red. Most remarkable dis- 
play after sunset. Continued the following days. 

First glow. A very peculiar reddish or brown light 
in E. before sunrise and in S.W. after sunset. 

Extraordinary sunsets. f 



Haze of a tawny or russet hue, and light of a bluish 
ghastly character. 

Great increase in brilliancy of glows. Mr. Bishop 
states the glows were renewed early in December,' 
and remained for six weeks as brilliant as in 
October. 

Glows returned. Duration 1 h. 30 m. to 2 hrs. 



Morning and evening glows. 

Sunsets began. Taken for aurora by many. 

Glow phenomena first seen. 



At 3 p.m., sun white, like electric light, with broad 
corona about 22° radius. Glow till about 5.45 p.m. 



Fine '* aurora.*' 



Displays began. On November 26 lasted till 5.30; 
on a later day till 5.45 p.m. 

Glows seen. At Lichfield, whole sky deep crimson 
on 26th. 

Sky blood-red ; most remarkable efiects. 



800 



THE HON. ROLLO RUSSELL 



Placb. 


Date. 


NOTKS. 


St. Andrews, Scotland (Mr. J. 
Dundas, MS.) 


Nov. 25. 


First display. Finest November 26 and 30. 


Montrose, Scotland (' Know- 
ledge,' December 21). 


Nov. 25. 


Sky filled with deep red colour after sxmset, like 
very bright aurora. Max. November 30, when 
sky was green, orange, and red. None Decern* 
ber 4 to 9. 


Dublin 


Nov. 25. 


Remarkable play of colours after sunset. 


Huntingdon, Canada— 45° N. 
74° W. (MS.). 


Nov. 26. 


Bky red one hour after sunset. 


Dorset, Vermont, U.S. (J. E. 
Clark, * Nature,' Jan. 3, 1884). 


Nov. 26. 


From about this date sky coloured istenaely red as 
by a great fire. 


Hee and Aalyke, Denmark — 
55° 30' N. 8° 62' B. (MS.) 


Nov. 26. 


First glow. From after sunset to 5.30. 


France (* Comptes Rendus,' De- 
cember 10, 1883.) 


Nov. 26. 


Glows first generally seen. Remarked at Paris, 
Nice, and Cannes ; and eight following days at 
Cannes, very intense. 


Cheltenham (Mr. C.Bol7,MS.) 


Nov. 26. 


Whole sky suffused with deep crimson of great 
intensity. 


Meltham (Mr. C. L. Brook, MS.) 


Nov. 26, 


Glow roand sun at 1 p.m. Ob following days fiery 
sunset glow. On 29th, to 5.30 p.m. On 28th 
clouds overhead greenish-yellow. 


Torquay, Devon (Mr. Glyde) . . 


Nov. 26. 


Glow very fine. Finest, November 9 and 26. Pecu- 
liar greyish haze, higher than the highest oirros. 


Ross, Hereford (Mr. Soutball, 
* Standard,' December 26). 


Nov. 26. 


Finest glow on this day. 


Croydon (* Standard,' see * Na- 
ture,* December 6). 


Nov. 26, 


Red sky at 3.30 p.m. 


Lyons, France (* Comptes Ren- 
dus,' December 24, 1883). 


Nov. 26, 


Glows began on this day, Very light cirri, in 
long and parallel filaments, were almost always 
observed. 


Whiteside Co., Illinois ; Spring- 
field, Illinois ; Humboldt, 
Iowa; Ohio; Johnson Co., 
Texas ; Waukesha, Wisconsin 
(Signal Service Report). 


Nov. 26, 


Glows began, in full splendour. 


Sumter Co., Georgia; Perry Co., 
Illinois ; Switzerland Co., 
Indiana ; Rush Co., Indiana ; 
Des Moines, Iowa ; York Co., 
Maine ; Cumberland Co., 
Mainland; Bristol Co., Mas- 
sachusetts ; Kent Co., Michi- 
gan ; Omaha, Nebraska ; Gal- 
veston ; Lexington, Oregon 
(S. S. R.), 


Nov. 27. 


Glows began, in full splendour. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



301 



Place. 



Date. 



Notes. 



Centreyille, Wisconsin (Signal 
Service Report). 



Bnitenzorg and Serang, Java 



Scntari, Asia Minor (Mr. W. H. 
Lyne,*Met. Register,' extract, 
MS.) 



Sontlianipton (* St. James' Ga- 
zette '). 



Oxford (* Daily Chronicle *) . . 

Ash by Parva, Lutterworth, 
Miss Annie Ley (* Nature/ 
Nov. 29th). 

Richmond, Surrey (* Nature '). . 



Cirencester ('Nature,' Decem- 
ber 6, 1883). 



Nov. 27. 



Last week of Nov. 

and beginning of 

Dec. 

End of Nov. 



London . . 
Nottingham 



Gliickstadt (Herr Gerber, *Met. 
Zeitschrift '). 

Meran--46° 41' N. 11° 8' E. 

C Met. Zeitschrift'). 
Bnxen ; Riigenwalde ; Neufalir- 

wasser (*Met. Zeitschrift'). 

Vilsen, Hanover (* Met. Zeit- 
schrift'). 



Keitam auf Sylt, Denmark 
('Met. Zeitschrift'). 

Paris (* Times,' December 6) . . 



Victoria, British Columbia 
(' Nature,' January 3, 1884). 

Gliickstadt ('Met. Zeitschrift'). 



Nov. 26. 

Nov. 26. 
Nov. 26. 

Nov. 26. 

Nov. 26. 

Nov. 26. 
Nov. 26, 
Nov. 26. 

Nov. 26. 
Nov. 26. 

Nov. 26. 

Nov. 26. 
Nov. 27. 
Nov. 27. 
Nov. 27. 



At 7.30 p.m. whole southern horizon bright crimson, 
centre apparently where sun sets ; glow extend- 
ing from W. to S.E. 

After-glows very conspicuous* 



** A remarkably deep red colour of the sky, clouds, 
and atmosphere has been noticed at sunrise and 
sunset on the last three or four days of the 
month ; giving to the sea, earth, buildings, Ac., 
a very peculiar ruddy, hazy, and weird-like ap- 
pearance." 

Very fine after-glow. Light very strong till after 
5, when east sky was of a strange green. Second 
glow till 5.46. 

Fine " aurora " after sunset. 

Altitude of red arc at 5.5 p.m., 25^. 



Sunset phenomena like yesterday, but much strongen 
Bright red. 

Magnificent display, nearly an hour. 



Peculiar glow round sun at 1 p.m. 
First glow vanished at 4.60. 
Bright red long-continued glow. 

Glows. Brighter glow on 28th. 



First glow. Compared to aurora borealis and 
reflection of a fire. 

Glows from this date lasted till 6.45 p.m. On 
Dec. 6th corona round moon. Sky never pure. 

Marvelloas glow. 



Brilliant aftei*-glow. Also very fine on 29th and 
December 2. 

First glows. Long after sunset crimson sky and 
rays like aurora. 

Bright red glow, as of a great fire, lasting till about 
5.40 p.m. 



2 R 



302 



THE HON. ROLLO EUSSELL 



Place. 



Date. 



Belfa8t—W 25' N. 32^ T W. 
(Met. Office Log). 

WooBter, Ohio (Prof. Stoddard, 
^Nature/ February 17, 1884). 



S. E. Iceland (MS.) . . 

Southern Sweden (Prof. Hilde- 
brandsson, 'Standard/ Dec. 
26). 

Banders ; Stendernp ; Jorgens- 
berg, Denmark (MS.) 

Newhaven, Connecticut, U.S.A. 
(Prof. Hazen, Synions's * Met. 
Mag.,' vol. xix., 1884, p. 37). 

United States (' Science ') 



Poughkeepsie, on Hudson 
(' Nature,' January 3, 1884). 

Wufltrow and Magdeburg (* Met. 
Zeitschrift'). 

Sunderland (Mr. Backhouse, 
MS.). 

North and South-east coast of 
France (' Coraptes Bendus,' 
December 3, 1883). 

Tarascon, France (* Comptea 
Rendus,' December 17, 1883). 



Belgium ('Met. Zeitschrift,' 
March, April, 1884). 

Great part of North Germany 
('Met. Zeitschrift,' March, 
April, 1884). 

Vienna ( ' Austrian Zei tsch rift ' ) 



Trient(* Austrian Zeitschrift'). 



Dalmatia and Corfu (* Austrian 
Zeitschrift '). 



Nov. 27. 
Nov. 27. 

Nov. 27. 
Nov. 27. 

Nov. 27. 
Nov. 27. 

Nov. 27 to end of 
Dec. 

Nov. 27. 

Nov. 27. 
Nov. 27. 
Nov. 27. 

Nov. 27. 

Nov. 27. 
Nov. 27. 

Nov. 28. 

Nov. 28, 29. 
End of Nov. 



Notes. 



Zodiacal light very plain. 

Glow very grand. On the days of the bright sun- 
set colouring, there was a sheen of 6° to ^^ round 
the sun. 

Fine sunsets. 

Beautiful and strange red sky after sunset. 

Glows seen. 

Bright after-glow. Fire engines called out. 

Glows conspicuous. 

Intense glow in sky. Fire engines called out in ibe 
morning. 

" Aurora in W.S. W." After-glow. 

Blue spot with pink semicircle opposite the snn. 

The glows conspicuous from this date. Frequently 
alluded to by observers as anrora borealis. 



Glow observed. M. Gasparin states, in * Comptes 
Rendus ' for February 4, 1884, that the after- 
glows were observed continuously from Novem- 
ber 19, 1883, to Januaiy 23, 1884. 

First glows. 



Glows observed. 



Glow first generally observed. Lasted tiU nm 
6 p.m., resembling a great fire or aurora. 

Magnificent glows. Very fine at 6.45 p.m.; and 
supposed by some to be aurora borealis. 

Glows. 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



303 



Place. 


Date. 


Notes. 


Lesina Q Austrian Zeitschrift '). 


Nov. 28, 29, 80, 
Ac. . 


Intense glovrs. Max. December 1. 


Wochein (* Austrian Zeitsclirift,' 
'Met. Zeitschrift'). 


Nov. 28, Ac. 


Glow. At Oberkram and Wochem began before 
6 a.m., and in the evening lasted till 6.30 p.m. 


Laibacli (' Austrian Zeitschrift/ 
'Met. Zeitschrift'). 


Nov. 28. 


Very fine glow like a fire. On 29th, like aurora, 
till 6.45 p.m. On December 6 the greatest inten- 
sity was at 6.40 p.m. 


Tabor (' Austrian Zeitschrift '). 


Nov. 28. 


Glows began. Very intense on November 30, 
lasted till 6.30 p.m. 


Berlin ('Austrian Zeitschrift,' 
•Met. Zeitschrift'). 


Nov. 28, Ac. 


Glows began. One evening the first glow sank on 
the horizon 50 minutes after sunset ; then, after 
5 minutes, secondary covering more than half 
the sky. 


Pera (* Austrian Zeitschrift ') . . 


Nov. 28. 


Glows began ; duration after sunset one hour. 


Munich (''Austrian Zeitschrift,' 
Professor von Bezold). 


About Nov. 28. 


Glows observed. 


Meran— 46° 41' N. 11° 8' B. 
('Austrian Zeitschrift,' ' Met. 
Zeitschrift '). 


Nov. 28. 


Glows seen. A s%ht glow was observed on the 
26th. On 28th, corona and very splendid even- 
ing glow. 


Turkey and Angora (* Austrian 
Zeitschrift'). 


Nov. 28. 


Glows seen ; lasted one hour. 


Hanover (' Met. Zeitschrift ') . . 


Nov. 28. 


Glows seen. 


Halifax, Nova Scotia (* Know- 
ledge,' February 8, 1884). 


Nov. 28. 


After-glows observed from this date; lasted from 
5.30 to 6.15 p.m. 


Bristol (Dr. G. F. Burder, MS.) 


Nov. 28. 


Magnificent sunset, finest. 


Austria (Dr. Hann, * Standard,' 
December 26, 1883). 


Nov. 28. 


Intensely deep-red sky after sunset, also 29th, sup- 
posed by some to be a tire. 


SuUempgard, Denmark (MS.) . 


Nov. 28. 


Glows seen. 


Beaumaris, N. Wales ('Daily 
Chronicle,' December 5). 


Nov. 28. 


First appearance of glows. 


Kirkcaldy (' Scotsman' ) ♦ . 


Nov. 28. 


Bright after-glow. 


Centreville, Wisconsin (Signal 
Service Report). 


Nov. 28. 


At 7.30 p.m. whole southern horizon bright crimson, 
from W. to S.B. 


Amsberg, Germany (Busch) . . 


Nov. 28. 


Glows. 


Bome, Naples, Brindisi ('Met. 
Zeitschrift'), 


Nov. 28 to 30. 


Splendid glows. On November 28 and 29 whole 
sky lit up. 


Lugano, Switzerland ('Met- 
Zeitschrift '). 


Nov. 28, 29, 30. 


Very intense after-glows. 



2 u 2 



304 



THE HON. ROLLO RUSSELL 



Plage. 



Date. 



Notes. 



Viareggio, Italy (* Standard' ). . 
Genera (* Met. Zeitsclirift '.) . . 



Rome (* Times * correspondent ; 
see * Nature,' Dec. 6, 1883). 

Goartenay, Loiret Q Met. Zeit- 
schrift*). 

Gastasegna and Sils-Maria, 
Switzerland {* Met. Zeit- 
Bchrif t '). 

Hamburg and the greater part 
of (Germany ('Met. Zeit- 
schrift ') 

Amiens ('Nature,' December 20, 
1883'). 

London ('Times,' Ac, Novem- 
ber 30). 

Scarborough (* Daily Ghronide,' 
November 30). 

Bray, Ireland (Mr. R. M. Bar- 
rington, 'Nature,' December 
13, 1883.) 

Gopenhagen (' Gomptes Rendus,' 
December 10, 1883). 

Ghristiania (M.Feamley, Direc- 
tor of Ghristiania Observa- 
tory. ' Gomptes Rendus,' 
1883, p. 1617). 



Nov. 28. 
Nov. 28. 

Nov. 28. 

Nov. 28. 

Nov. 28, 29, 30. 

Nov. 28, 29,30. 

Nov. 28 and 
Deo. 1. 

Nov. 29. 
Nov. 29, 
Nov. 29. 

Nov. 29. 
Nov, 29, 



Splendid after-glow. 

From this date splendid morning and evening 
glows. 

Magnificent crimson glare like aurora. 



Splendid colourless circle round sun. 



Till about 6 p.m, splendid glow. 



Very fine and intense glows. 



Greatest intensity of glows 28th and December 1, 



From about 5.30 to 7,30 a.m. dark-red sky, sapposed 
by many persons to be from a fire. Simrise 7.43. 

Extraordinary sunrise. 



At 4 a.m. rosy hue. 



Glows began. Lasted till 6 p.m. after sunset 



Glow observed. 



Slangerup, Denmark . . 


• . 


Nov, 29. 


Glows. 


Videbok, Denmark— 66** 6' N. 
8° 39' B. (Hoffmeyer, * Stand- 
ard,' December 26). 


Nov. 29. 


Very fine after-glow. High cloud-stratum like 
drapery. 


Videbok, Denmark (MS.) 


• . 


Nov. 29. 


Red light on western sky first seen. Very bright, 
the most beautiful red the observer had ever 
seen. 


Trient ('Met. Zeitschrif t ') 


• . 


Nov. 29. 


Duration till 5.45 p.m. 


IschU'Met. Zeitschrift') 


• • 


Nov. 29. 


Duration of very intense glow till 6 p.m. On De- 
cember 1st, morning glow began at 5.30 ; very 
grand at 6 a.m. Sky seemed to be covered bj 
a delicate veil. 



ON THE FIEST APPEARANCES OF OPTICAL PHENOMENA. 



305 



Place. 


Date. 


Notes. 


Janerberg, Carinthia (* Met. 
Zeitschrift*). 


Nov. 29 to Dec. 2. 


Glows from 6 a.m. On November 29th magnificent. 


Switzerland (* Met. Zeitschrift,' 
Ac.) 


Nov. 29, 30. 


Glows. 


Davosplatz, Switzerland (Mr. 
J. A. Symonds, in ' Pall Mall 
Gazette *). 


Nov. 29. 


Rosy flame like northern lights long after the ordi- 
nary glow had disappeared. Sun surrounded by 
opalescent haze. 


Germany (*Met. Zeitschrift'). , 


Nov. 29, 30. 


Glows general. 


Whole western half of Anstria ; 
Sonth Dalmatia to north 
border of Bohemia ('Austrian 
Zeitschrift'). 


Last days of Nov. 


A quite extraordinary morning and evening glow 
observed. 


EIremsier. • 


Nov. 29. 


Glows. 


Algiers . . 


Nov. 29. 


Glows began. 


Madrid (Mr. McPherson, Mr. 
Gillman,*Natnre,'and Times'). 


Nov. 30 or before. 


Glows began. 


Naples (Padre Denza, 'Natnre,' 
Dec. 20, 1883). 


Nov. 29. 


Whole sky lit up. 


Marianhorg, Denmark . • 


Nov. 30, 


Glows observed. 


Lerwick, Shetland Islands 


Nov. 30. 


Marvellous sunsets, beginning before this date. 
About 6 p.m., on Nov. 30, the whole southern 
sky was tinged with a brick-red light, like the 
glare of a great conflagration. 


Six-Mile Bridge, Co. Clare, 
Ireland (Rev. E. Lloyd, MS.) 


Nov. 30. 


Very fine sunset. 


Worcester, England (Mr. Boz- 
ward, * Nature,' Dec. 6). 


Nov. 30. 


At 6.15 p.m, red arc 26° high. 


Frauenfeld ('Met. Zeitschrift,' 
* Austrian Zeitschrift '). 


Nov. 30. 


Splendid after^-glow. First notice of the glows. 
Duration 1 hour 52 minutes. 


Warsaw (' Met. Zeitschrift,' 
' Austrian Zeitschrift '). 


Nov. 80. 


After-glow till 5.30 p.m. Described as zodiacal 
light. 


Sweden (Hildebrandsson, • Stan- 
dard,' Dec. 26th). 


Nov. 30. 


First genernl observation of glows. At IJpsala, at 
4.30 p.m., the whole sky was transformed into a 
red cupola. 


Basle to Calais (on the way 
from). 


Nov. 30. 


Magnificent momiug glow from 6,30 a.m., and 
evening glow till 6.30 p.m. 


Cape of Good Hope (*Met. 
Zeitschrift '). 


Not. 30. 


Glows. 



306 



THE HON. ROLLO RUSSELL 



Place. 



San Salvador, Central America 
<*Met. Zeitschrift,' March, 
April, 1884). 

A8ante^l9°'6 N. 66°-9 W. 
(*Met. Zeitschrift'). 

Droskeniki, Russia (MS.) 

Zi-ka-wei (Shanghai) . . 



Mobile, U.S. 



Stockholm and Christiania 
Q Nature,' December 20, 
1883). 

La Hendaje, France (' Nature,' 
Dec. 6, 1883). 

Fredericton, New Brunswick 
(W. Brydone Jack, 'Nature,' 
January 17, 1884). 

British Isles, France, Switzer- 
land, Spain, Constantinople, 
Lesina, Marseilles (* Times,' 
Ac). 

Louvain, Frauce 



Marburg (* Met. Zeitschrif t ') • . 
Rome (Mr. T. Henderson, MS.) 
Nice 



Date. 



Notes. 



Freiburg. 



Brixen (* Austrian Zeitscbrif t ') 



Gmunden (' Austrian Zeit- 
Bchrift'). 

Salzburg ( ' Austrian Zeit- 
schrift'). 

Orange, France . . 



Nov. 30. 

Nov. 30. 

Nov. 30. 
End of Nov. (?) 

End of Nov. 
Nov. 30. 

Nov. 80. 
Nov. 30. 

Dec. 1. 

Dec. 1. 

Dec. 1. 
Dec. 1. 
Dec. 1. 

Dec. 1. 

Deo. 1. 

Dec. 1. 

Dec. 1. 

Dec. 1. 



OlowB seen. 



Pretty strong after-glow. 



Glows observed. 

At the beginning of December the glows nearlj 
ceased, but after a few days their intensity was 
renewed. 

Maximum last week of Norember and first week of 
December. 

First glows. Lasted from November 30 to middle 
of February. Intense after-glow like a great 
conflagration on November 30. 

Glows observed. 



On this day whole heavens red before sunrise. 



Great intensity of glows. At Constantinople dura- 
tion 1^ hour. In London the glow was visible 
behind clouds till 5.45 p.m. 



At 4.25 p.m. western horizon greenisb-blne; rosy 
glow to zenith. 

Marvellous glow, bathing the landscape, at 6 a.m. 

First remarked glow. 

First glow lasted to 55 minutee, second to 90 
minutes after sunset. 

On this date the glows were at their maximum; glow 
very intense two hours before sunrise. 

Began before 6 a.m. Lasted till 7 p.m. after sonsei 
Very fine glow like aurora borealis. 

Flaming red 6 a.m. Blood- red 5 to 6 p.m. 
Most brilliant from 6 a.m. 



At 6.15 a.m. appearance of a tremendous fire raging. 
At 6.20 it seemed as if the sun were about to 
rise. At 6.40 extensive yeUow, at 7 greenish. 
After-glow visible till 7 p.m. 



ON THE FIRST APPEARANCES OF OPTICAL PHENOMENA. 



307 



Place. 


Date. 


Notes. 


Grauheim-eri N. 8"-6 B. . . 


Dec. 1. 


Evening glow ; also Januaiy 1 and February 27. 


Kiel ('Met. Zeitsobrift,' March, 
April, 1884). 


Dec. 1. 


Whole sky bright red and violet after sunset. 


Malta 


All through Dee. 


Glows. 


W, Austria, Dalmatia to N. 
Bohemia CZeitsch. fur Met.') 


First few days of 
Dec. 


Glows. 


Europe generally, excepting 
RoBsia. 


Dec. 1. 


Glows brilliant. 


Athens ('Daily News,' Dec. 8). 


About Dec. 1. 


Brilliant after-glows seen every morning and even- 
ing from about this date. The displays at sun- 
rise and sunset lasted fully 1^ hour. 


United States, c.gr., Archer 
(Florida), Andersonville (Ge- 
orgia), Oskaloosa (Iowa), Fort 
Scott (Kansas), Genoa (Ne- 
braska), Portland (Oregon), 
Ac. 


Dec. 1. 


Glows. 


Upsala 


Deo. 1. 


Sunrise extraordinarily splendid. 


Videbok, Denmark (MS.) 


Dec. 1. 


Marvellous light redness after sunset. White bright- 
ness till 2 hours after sunset. Olive-green in N. W. 
for a similar time. 


Honolulu • • 

• 


Early in Dec. 


The glows were renewed, and as brilliant as in 
October. 


Akureyri, Iceland (MS. from 
Akureyri, dated Feb. 2, 1884). 


Autunm. 


" Just since autumn a most peculiar phenomenon — 
a dark-red light on horizon, sunrise and sunset, 
and olive-green in north-west, just like what may 
be seen at great volcanic eruptions." 


Crimea 


In Deo. 


Glows. 


Mauritius 


In Dec. 


Glows continued. After-glow began 14 minutes after 
sunset and lasted 24 minutes. 2nd glow began 
38 minutes after sunset and lasted to 1 hour 17 
minutes. In the morning the first glow appeared 
at 1 hour 26 minutes before sunrise. 


Reykjavik, Iceland 


During Dec. 


Glows. 


Vittoriay Spain 




In December the glow was observed to last 1 hour 
45 mins., and on another occasion 1 hour 56 mins. 


Riviera, Italy 


Deo. 


The glows continued through the month. 


Russia (MS.) 


During Dec. 


The glows were observed from Belostok, 6.3° N. 23^ 

E. in the west, to Perm, 58° N. 57° E., in the east. 


Pulkowa, Russia 


Dec. 


The twilight lasted when the sun was more than 18° 
below the horizon. 





■ 


i . ^^ 308 * ^^^* 


THE HON, ROLLO RUSSELL ^^B 


^^■11 


Plack. 


Datk. 


NorEfes, 


^^m 


Ban Salvador^ Central America 


Dec, 2, &c. 


Glows this day and daring the mon 


^^^^^1 


1 Valence, France-. 


Dec, 2. 


Duration of glow till 6.16 p.m. 


■ 


i ^ Naples (Johnston- Lavis, * Daily 

News/ December 8, 1883). 


Dec. 2. 


Morning red at 5,;i0, " First the 

on the horizon, then it spread 
invisible mist high in the sky, 
faded away, and a cnrious yellS 
spread the laud.^cape, and when, 
7.15, the sun at last peeped above t 
that luminary was dazsEliug white, 1 
liLinp, Bluish moon and remarkabl 


I^HU 


Madrid (Gillman, ' Nature,* Be. 
cember20, 1883). 


Deo. 2. 


Evening red till €.15 (eonfiet 424) j 1 
6 p.m. 1 


Hi^^l 


Homo 


Dec 2. 


Glow magnificent ^^| 


1^1 


SjdTiey, N.S.W. (Mr. Har- 
grave'B MS.) 


Dec. 2. 


Sunset 6.55 ; white haze 7 6 ; pink 7^ 
Etteel'blaej pink on horizon, tnm« 
2nd glow began 7,40 ; all oTer, SM 


H'l^^H 


RUraaa— 62" 35' N, 11" 23' E. 


Dec, 2, 


Extmordinary glowe, 3 to 4 p,m- 1 


1 ^^^1 


■; Stenkjecr^^" 1' N. IF 25' E. . . 


Dec. 2, 


Extraordinary glowe 3 to 4 p.m. 1 


■ ^H 


H; Amnti^2VB N. 65^e W. (*Met. 

■ Zeitschnft*). 


Bm.% 


Fiery glow. ^^M 


HI 


B Europe and Nortli America, 
B Indi a, Anstml ia, Nortli Atlan- 
H tic, Indian Ocean, part of the 
M Pacific Ocean, Now Zealand. 


Early m Deo. 


Glows Yeiy strong* ^^M 


^^^1 


m Lisbon (Captain De B. Capello, 
■ ' Standard; December 26). 


Dec. 3, 


Snnaet about 4.35. Glow up to G( 
appeared 6.30. 


^^^1 


1 1 Madrid (Mr. Gillnian, * Natnre,* 
■ | December 20), 


Dec, 3. 


Clond-ripple and glow. On Dec^i 
till 6.15. 


^^^1 


Hi OherhUrgermeigter von Whiter — 
■ 32" N. 2i" W. (■ Met Zeita/). 


Dec, 3. 


Sky copper-red at annaei. 


M^l 


I Crete— 35^ N. 2h'' E. (^ PM Mall 
H, Gazette/ December 5). 


Dec, 4, 


Tery brilliant " aurora *' 5 to 8 p3 
crimBon, and pink. 1 


^^^H 


I OJar— 40" N. 72" W. ('Met. 
■ Zeitscbrift '). 


Dec. 4. 


Yery strong morning glow, like anid 


HH 


H Bicbmond, Surrey {Hon, R. 
m EaEBell) 


Dec. 5, 


The first appearance of a glow in tS 
day began at 25 miontcs after sai 
till 4.50, 55 minutes after sunseL 
after dark. 


^1^1 


H Stonyhnrst {' Natare/ Dec 13), 


Dec, 5. 


Strong ab&orption bands between A i 


^^kL^I 


H Buda Pesth (Herr Gothard, 
H ' A tistri an Ze i tscb ri ft *) . 


Dee- 5. 


Red end of Bpectrom ei^mopffiji 
Simply a mocliJied aoUr spftolmy 

_j 



ON THE FIRST APPEARANCES OP OPTICAL PHENOMENA. 



309 



Place. 



Tnnbridge Wells, Kent (Mr. E. 
D. Archibald, 'Nature,' De- 
cember 13): 

England. • 



50° N. r W. ('Met. Zeitschrift ') 

WiVhelm—h(f N. 22^ W. ('Met. 
Zeitschrift'). 

1^. America, Switzerland, Spain 

Richmond, Surrey (Hon. R. 
Ruasell's Register). 



Berlin 

lfa^dafcna-44°7N. 39°-7 W., 



JBellerophon — near Singapore 
(Met. Office Log). 



Datb. 



Paris 



Lochee-2S° 46' S. 29° 26' W. 
(Met. Office Log). 

Cariente8—20°'SN.22'''6W. .. 



Magdalena—iff"! N. 30°-6 W. 
('Met. Zeitschrift'). 



Kew, Surrey 

Toumai, Belgium • • 

Angora, Asia Minor (' Met. Zeit- 
scbrift,' 1884, p. 29). 

Kiaohta^ Siberia (' Times ') • • 

Asante—2Sr'4 N. 64°1 W. . . 

Oberburgermeister von Winter — 
19°-3 N. 23°-5 W. ('Met. Zeit- 
schrift'). 

flftmJeafn^35°22' N. 46° 10' W. 
(Lady Brassey). 



Dec. 6.. 

During Dec. 

Dec. 6. 
Dec. 6. 

Dec. 7. 
Dec. 7. 

Dec. 8. 
Dec. 9. 

Dec. 9. 

Dec. 9. 
Dec. 10. 

Dec. 10. 

Dec. 11. 

Dec. 11. 
Dec. 11. 
Dec. 12. 

Dec. 11 to 25. 
Dec. 13. 
Dec. 13. 

Dec. 13, 14, 15, 16. 



Notes. 



Cirriform haze and glow. 



The white parallel streaks like cirro-stratus, noticed 
by many observers. This apparent cloudiness 
decreased continuously. 

Red corona round the moon. 

Remarkable red corona round the moon. 

Intense glow. 
Glow much fainter. 

Streaky greyish- white cloud parallel to the horizon. 

From 6 a.m. very bright glow, and also from 5 to 
5.45 p.m. 

Large halo round moon. A few days later peculiar 
pale red haze round moon. 

The glow lasted 1 hour 43 minutes. 

Beautiful bright red sky at sunset. 



Very clear air. At sunrise most extraordinary and 
alarming colours as. before hurricanes in Indian 
Ocean. This lasted till after passing the Canary 
Islands. 

Very bright glow from 6.30 to 7.30 a.m. 



Sky still glowing at 5.27 p.m. 
Glow till 5.30 p.m. 
Glow seen. 

Brilliant after-glows. 

Strong glow. 

Leaden-t;oloured sky, and 1 hour after sunset 
blood-red. 



Most magnificent sunrises ar d sunsets, with second- 
ary glows like northern li^f hts. On December 16 
the entire sky suffused with clear orange colour, 
fading into delicate bluish-green. 



2 s 



Vn„ 


^^^^^^^^^^^^^^!v^^^^^^^^^^^^^^^^^^^^H 


Hi 


^^^1 


Jl 

1 . .. . _ .1 .1 1 1' 1 


^ 310 


THK HON. ROLLO RUSSELL "^M 


1 n ■ 1 H 1 1 1 1 H H'' 


k PJ14CB- 


Datb. ' 


NOTIB. 




1 lf^wr^l9^6 If. 34°*5 W. 
J CMet. Zeitechrift'). 


Dec. 12 to 14. 


Beddmh-jellow alieen round moon. 
snn had a similar sheen. 




1 Jfa^rfa?i5tt^-47"'8 K. SrS W. 

('Mat. Zeitachrift^}. 


Dec. 13. 


Strong glow from 6 a.m. to 7.30, 




T»i Yuen Fu ShanBi, China 

{* Nature/ Miiy 22, 1884J. 


In Deo. 


Glows. ^M 




Reunion ,, ,. ,* 


Dec. 


Ulows rapidly diminiBhed from tlie i 
end of December, when they ceaaed 


i^^^^^^^^^^^^l 


Stonyhnrst, LaTicaBhire (Rev. 
1 S. J. Perij, F,R,S.) 


Dec. 16. 


Maximum on tin's day. Glow mmhii 
50 minutes after sunaet. 


■ 1 ^^^^^H ('Met ZaitacbHrt*). 


Dec. 16. 


Very bright glow 6 to 6.45 a.m, and > 


H 1 ^^^^^^hFiI Crimea 


Dec. 16. 


Yery fine glow, snpposad '* anrora." 


■■^^^^Hkl BunheamSS'' 57' N. 38' 22' W. 


Dec. 17. . 


Magnificent snnset, bi-ight reds an< 
December 18 and 19 whole sky coli 


^^^^^^^^^^^H 


Dee. 17. 


The illnminated aky distinctly striate 


^^^^^^^H Yadgd'-7(f 4' K 20" 4.y E. .. 


Deo. 18 to 25. 


Glows strong 3 to 4 p,m. 




^*ante— 35^2 N. 46^2 W, 
(' Met. Zeitschrift;} 


Dec. 19. 


Strong glow. ^^M 




1 Aaleannd, 62"-3 K.6"9 E. ■• 


Dec. 20. 


Qrlow 430 to 5 p.m. ^^ 


^^^^^^^H| TomngeD, 25^ N, B"" 48' B. 


Dee. 25. 


Glow from sunset to 6 p.m* ^^M 


^^^^^^^Hi J^mfe-36'a IS^. 42''6 W. (*Met. 


Dec. 21, 22. 


Strong glow. On 22nd over nearly t] 


^^^^^^^^H Bydmy.l^.SM,.. 


Dec. 26. 


Sunset 7 J 2. First glow setting an< 
appeaj'ing 8 p.m., red still irisible 1 


^^^^^^^^^^^H Pay de Ddme, Aurergne 


Dec. 27. 


At 6 p.m. light enough to read hy. 


^^^^^^^B ThMmlu»~27^ 50^ 45' E. 


Dec. 28. 


Fixjro 7 to 8 p.m. sky after sunset ai 
Vftrietv of tints Tuost beaotifuHy mil 
on 30th in 28" 43' S. 45" 3' E., and j 
days. On January 1, 1BB4, befor^a 
red. On January *1 2, at 4.30 a.m., m 
sky red to the eastward. 1 


^^K|l ^^^^^^1 HaakoWf N, China 


Dec. 29. 


Green sun and red glow, 1 


^^^^H il ^^^^^^^^H 


Pekin, China (Report of P*^- 
kin Hospital, " Met. Zeit- 
HchrifE,' March, 1884). 


Eud of Deo. 


Glows. ^H 


^H V ^^^1 


^ J 



ON THE FIEST APPEABAJSTCES OF OPTICAL PHENOMENA.. 



811 



Place. 




Notes. 



Dresden 



Hftmbiirg 



Eorope and Amorioft • • 



Europe and North America 
C Met. Zeitschrift,' March, 
April, 1884). 



Dec. 30. 



Dec. 31. 



End of Dec. 
1884. 

Jan., Feb., Mar. 



Europe and North America 



North Atlantic 



April to Dec, 
1884. 



1884 



Aiusiralia, New Zealand, and 


1884. 


the Southern Indian Ocean. 




India and China. • 


1884. 



Astronomical twilight lasted till 6.24 instead of till 
6.4 p.m. 

At 5.20 p.m. glow strong enough to <iaat shadows. 
At 5.54 second glow ended. 

Great intensity of glows. At Ben Nevis, on De- 
cember 30, colours most magnificent. 

The glows were generally observed through January 
and February, and steadily declined till in most 
places they became invisible in March. In the 
province of Vitebsk, Russia, they were noticed 
at the beginning of March, as soon as the clouds, 
which had obscured them for 3 months, cleared 
ofF. The decline of the glows was marked by 
shorter duration, fainter coloration, and absence 
of the secondary illumination. Their decrease 
was far more gradual than the rapid increase in 
November, 1883. On January 24, 1884, Pro- 
fessor Earlinski saw at Cracow a splendid green 
sun. 

Occasional crepuscular displays were seen in the 
course of the summer and autumn, but seem to 
have been more local than general, and not 
comparable in brilliancy with the earlier phe* 
nomena. 

There is not much evidence of the continuance of 
the glows over the ocean ; but in January espe- 
cially it was occasionally observed. As a rule, 
the phenomena had become so common as no 
longer to be* noted. Near Madeira the glows were 
fine till the end of March. On February 18 and 
24 they were observed at 36° N. 36° W. and 25° 
N. 28° W. In 16° N. 42° W., on March 25 the 
sunset was magnificent, with fine lines of ciiTO- 
stratus and a dark red glow. 

Glows occasionally fine in February and March, but 
very fitful and sometimes not seen at all on clear 
days. The duration continuously decreased. 
Some fine glows in Australia several times between 
March and October. Pink glow still visible at 
Nelson, N.Z., on July 1 and 2. On February 24, 
in 10° 3' S. 99° 53' E., the western sky was 
brilliantly yellow for about half an hour. On 
March 3, in 18° 34' S. 82° 17' E., there was 
a peculiar green in the sky before and after 
sunset. 

At Poona, in India, on January 8, the blood-red 
skies are reported as beginning to fade. In China 
the glows continued during January. 



2s2 




312 



THE HON. ROLLO RUSSELL ON THE 






PtiCE, 


DiT«. 


^orm. 


Central America 


18&4. 


The msximum glow at Panama was ti 


Sooth Africa 


1884. 


Glows conapicnona in March, April, i 


Bourbon Island . . 


1884 


The cpepnsenlar phenomena wera 
April. 


South America * . 


1884, 


At Monte Video the after-glows conHl 


TavoT, Bttrtuah (Mr, WallacCj 
MSO 


1884. 


The plows were observed in Janns 
more marked in Febmary and Mar 


Kew Caledonia and the Western 
Paciac (Katnre; March IB, , 

1884). 


1884. 


The glows continned in Jannarf . 


' * "1 



PAET IV., SECTION IIL (a). 

General Geographical Distrtbutton of all the Optical Phenomi 
and Time ; including also Velocity of Translation of Smokj: 

My the Hon, Hollo Russkll. 



Geographical Distribittion of PEcirLLA.R Sky Phenomenj 

In the early part of 1883 we find two or three notices of fine snns< 
special report of them was made at the time by any competent obsenrer, n 
we can leani, were these sunsets distinguished in any respect from those d 
beautiful and quiet character which may occur in any year, and almost \ 
The most noteworthy observations are those of Mr. Neison, Director of 
ment Observatory at Natal* He says that on February 8 th^ 1883, he ma 
of one of the sunsets which began to be noticeable about that time. Tha 
unfortunately been destroyed. They were on a less grand scale than i 
following autumn, but became gradually more marked till June. Then for 
nothing was noticed. On August 2lBt and 22nd they were noticeable, bii 
On August 28th and 29th they were most vivid, and till September 5t> 

• *Knowkdge,^ June 6. 1884 




GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 313 

redness of the sky was most remarkable, fading away into green and purple in the 
east. After this the uncommon sunsets did not recur for four months, except in a 
very faint degree. In February and March, 1884, they again became very noticeable, 
but early in April, 1884, had again disappeared. Mr. Neison's account is difficult to 
interpret, as reports from the Transvaal, the Cape, and the Ocean east and south, give 
details of extraordinary glows seen first early in September, then from September 
20th continuously through October and November, 1883. He observes that at only 
250 miles distant, in the Transvaal, the glows were most vivid until the end of 
January, 1884. With regard to the sunsets of May and June, 1883 (the exact dates 
are wanting), in Natal, it may be worth noting that the first eruption of Krakatoa 
occurred on May 20th, 1883 ; and as to the sunsets of August 21st and 22nd, we now 
know that from August 11th to 18th the volcano was emitting enormous volumes of 
smoke and dust, causing showers of sand and ashes. 

A remarkable sunrise was seen firom the Tilkhurst on May 22nd in 33° S. 29° E.,. 
a peculiar sunset in 39° 18' S. 93° 25' E. on May 24th, and a red sky at sunset in 
36° N. 3° W. on June 1st. 

A white haze and strong glare were seen on board the Viola on May 24th in 
16° ir N. 26° 55' W. ; and on May 27th, in 9° 59' N. 28° 9' W., the haze continued, 
with a fall of reddish sand, and the sun looked like melted glass. 

If Krakatoa be assiuned to be the origin of these last phenomena, the products 
of the eruption must have been carried in a direction a little north of west at the rate 
of about 100 miles an hour, but the effects in this case were much more probably owing 
to sand from the African desert. 

On July 16th and 17th there were a bright yellow sky and blue moon after sunset 
in 8° 52' N. 85° 52' E., accompanied by other phenomena greatly resembling those 
which afterwards occurred over a wide area in September. 

After the May eruption the dust must have travelled south-westwards at the 
rate of about 103 miles an hour, if the scarlet clouds at sunrise seen on board the 
Tilkhurst were due to its having affected the neighbouring part of the atmosphere ; but 
it seems not improbable that the sun in rising may have been reddened by this dust 
in the upper atmosphere 8° to 10° further east, as the Tilkhurst has no record of a 
correspondingly brilliant sunset on May 22nd. In that case the velocity did not 
exceed 93 miles an hour. Little reliance, however, can be placed on the few obser- 
vations of this period, which do not distinctly record phenomena of an extraordinary 
character. The peculiar sunset in 39° 18' S. 93° 25' E. would show a rate of about 
25 miles an hour. 

The bright sunsets of August 21st and 22nd, in Natal, if due to the activity of 
Krakatoa on August 11th, would also show a rate of about 25 miles an hour. 

A beautiful sunset, but nothing more, was reported from Nashville, Tennessee, as 
having occurred on August 22nd, 1883, and one was reported from Logansport, 
Indiana, on August 14th. 



314 



THE HON. ROLLO RUSSELL ON TI 



141 1 



Colonel WarDj at Parbenkirchen^ Bavaria, notioed some fiue red 
Aipenglukenf in Bavaria, in the early part of the summer of ISSSj especi 
and recorded them iu his register at the time. 

With the exception of the observations of July 16th and 17th ia 
Ocean, there appears to have been no striking manifestation of abooii 
phenomena before August 26th, 1883, Even on and after this dat^ 
elighter phenomena may have been due to the previous activity of Kj 
to the eruption of Gunong Api, Molaccas, on the night of August 
An eniption at Sandalwood Island, seen by the Rev. J. E, TenisoN! 
August, may possibly have produced some of the effects noticec 
observations made on boaid the Beljmt^ and other ships, towards the 
and in June, indicate the probable existence of a very rapid up 
from the Strait of Sunda in a south -westerly direction* The later 
of August, coinciding with an actual fall of dust* make it certain 
month such a current existed, not dependent on the direction of the vi 
winds. 

On August 26th, on board the Ardgowm, in 7° 54' S. 85'' 37' K, th 
" all of a flare f in 5*" 38' S. 106'' E* the ciouda were red and yello 
93*^" 2 K the whole sky was of a peculiai' red, like bright' polished cop 
Foochow, 26'' 7' N, 119° 18' K, there was a light like aurora borealis. 
100 miles south of Javas First Point the sky was extremely overcast, 
during the 26th, explosions having been heard during the previous night* 
by the evening of the 26th, a very considerable area in the Indian Oceas 
west of Krakatoa was subject to unusual phenomena. On the morning 
at Telok Betong, near the Strait of Sunda^ the sky was of a copper coloi 
in Ceylon the sky was murky in the morning ; and a green sun waa 
evening* Between 4 and 5 a*m, on the 27th there was a red illumination 
Semanka, At about DO English miles north-east of Krakatoa the sky waa 
of changing hues, at 4.30 a,m- The sun^ on emerging from the dark cloud 
seen green at Batavia on August 27th. Peculiar effects on the sun anc 
have extended rapidly in a N,N.E direction, for they were seen at 
Banguey Island on or about August 27th, and in Japan on August 29 
3lHt; also at Cbeefoo on August 29th, in 37'' 24' N. and 121'' 2a 
appearances in Japan were due to the eruptions in the early afternoon 
the haze must have been carried by an upper current at about 47 mil 
that direction. The upper clouds oliserved in the preceding fortnight 
voyage of the Scotia from Japan to the Indian Ocean, show that an 
from between south and west prevailed as far as about 27° south, and % 
to north-east, while the lower wind was south-west. 

• MS.i and 8ymoks*w Monthly * MeteornlogiCBl Mogasin^.' 
t Sydney " Moruing Herald/ January lt>, 1884. 



GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 315 

Another current seems to have conveyed a portion of the ejecta in an easterly 
direction, for on September Ist, at New Ireland, 3^ S. 152° E., and on September 3rd 
at New Hanover, the glare was observed, and a fall of dust occurred off the north- 
west Cape of Australia on August 30th. 

The mass of the ejecta seems to have been carried with great velocity west- 
wards and south-westwards at a very high level. Already on August 27th the 
atmosphere at Seychelles, Rodriguez, Diego Garcia, and Mauritius was affected by a 
haze. This may have been partly due to eruptions on the 25-26th and 26th, or to 
the almost continual eruptions of the previous week, but by six in the evening the 
appearances at the Seychelles were of a striking character. In the evening the haze 
was strong enough to cause a red glare at the three islands first-named, which lasted 
till 7.15 p.m. The haze between Krakatoa and Madagascar is noticed in several logs 
on the 27th, and as far west as 91° E. there was a fall of dust from the 27th to the 
29th. The Tweed had a fall of ashes at about 370 English miles from Krakatoa in 
the direction of Keeling Islands. And at Keeling, or Cocos, Islands, dust fell thickly 
from 4 p.m. on August 27th. On the 28th, in 9° 15' S. 93° E., the sky was white and 
the sun reddish-yellow, with a shower of sand, and at 6° 12' S. 88° 17' E. the sky was 
very hazy, a constant shower of white powder falling. At this longitude the haze 
and fall of ashes extended to about 8° S. at least, probably much fiurther ; and at 
6° N. there was a complete circle round the sun, but nothing else unusual was noted. 
On the 28th, while ashes fell in Sumatra, and dust as far as 1140 English miles 
west of Java Head, the sun was much obscured, as by a fog, at the Seychelles, and was 
also dim, with a strange sky, at Diego Garcia and St. Brandon. At Mauritius there 
was a crimson dawn and the sun was red after rising ; while in Natal on August 28th 
and 29th most vivid sunsets were noticed. At 25° S. 61°'5 K there was a bright sky 
in the evening of the 28th. Thus a dense band of haze seems to have existed on this 
day within a few degrees of a line drawn from Krakatoa to the Seychelles, with falls 
of dust along about one-third of that distance ; while much further south the matter 
in the upper air caused brilliant effects after sunset or before sunrise. The twilight 
effects so far, preceded the obscuration of the sun ; in Japan a red glow was seen from 
12 to 24 hours before the sun was notably dimmed. The reason for this becomes 
evident by further following the propagation of the haze ; wherever it was dense the 
red twilight effects were Uttle noticed or absent. Thus the red twilight of August 
27th in the western part of the Indian Ocean was probably caused by a thin haze in 
the upper air proceeding from the eruptions before the great outburst of the 27th. 
The green sun affecting a small part of Ceylon on the 27th and following days 
may have been caused by an intermediate ciu*rent bearing northwards some of the 
thick dust which, according to the Brani and other vessels, must have been felling 
from the main K to W. stream at a high level during the 27th, at 3° S, 92® 11' E., 
and probably much further westwards. A variety of currents must have existed 
between the surface of the earth and a high level ; for, the dust or haze was in a short 




INI 



HIG 



THE HON, HOLLO RUSSELL ON THE 



time widely distributed in various directions. Mr* Verbeek mentioS 
existence of two currents, one from south-east and the other from i 
which the dust was transported. But tlie products of the 27 th seem 
80 krgely projected to a very high level that they ware carrie-d swiftly 
direction without immediately aflecting latitudes much north or south 
in a gieater degree than the eruption of the 26th, except perhaps h3 ri 
The green sun of the 27th at Ceylon and L#abuan lasted only a short 
not generally observed in any large area. In fiict, the tibsence of green 
in the Indian Ocean before September 8 th deserves particular notice. 

On August 29th, from about G° S. 88° R to 2° 37' S. 79° 52' E., 
over a very large extent of the Indian Ocean, dust was falling and the 
hazy, the sun being nearly obscured, both on this day and on the 3( 
yellowish haze. On the 29th a remarkably coloured sky was seen 
52''-9 W., and at 55° 56' S. 62'' 51' W., but these observations are isolate 
considering the manner of the distribution of later effects, they were 
of the consideTuble eruptions of August 11th, 14thj and IGth; and th^ 
of August 2l8t and 22nd at Natal would similarly be due to the pre 
south-westerly direction of the products of those eruptions* At the 
should be borne in mind that a great storm was passing a little soutl 
52°'9 W. on August 29th, which may presumably have been concerned; 
the colours there noticed » 

On August 30th the firat phenomena of a peculiar charactarwei 
a few places west of Africa, A remarkable sky was noted at lO'^N. 26*^ 
S. 20^ W. after sunset, and as far west as Maranham, about 2"^ 30' S 
the most interesting observation is that from St, Helena, 16° S, 
at 4 a,m, on the 30th a red light in the south-east and south-west, 
alarmed one of the inhabitants. This was the first instance of a compar 
which was afterwards frequent. Tlie glow stiU prevailed far south ii 
Ocean, at 2G°-5 S. 56'' 5 E. A fall of dust off the north-west coast of Ata 
to the evidence of a surprising variety of intermediate upper currents. 

On August 31st, in 1° 20' S, 21*^ W,, at 8 a^m* the sun was cop 
2*^*3 S. 4*^" 7 E, veiled with a silver-white sheen, and strange appearan 
from 13° 33' N. 31'' 29' W, to Natal, and probably much further west in 
At Maranham the sun was dim at 7 a.m. 

On September 1st the blue sun band extended across the Atlantic 
west, reaching even to Guayaquil at 80*^ W, in the latitude of 2"^ S* ; 
12^7 S, 27^-3 W. and 10^ 40' N. 26\3o' W. in the mid-Atlantic. The 
appeared at Santiago, Chili, 33^ S. 71° W, about this time, and a rec 
was seen long before sunrise in 11"^ N, 25° 27' W.> but there is no 
further west in north latitudes* 

On September 2nd the whole northern part of South Am ericas 



GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 317 

Antilles and Peru, and between Panama and Paramaribo, seems to have had a blue 
sun ; and in many places a red light was seen long after sunset. A grey sky still 
covered the Atlantic, and at 4° 41' S. 31° 10' W. the sun, about 5 p.m., was pale blue. 
Meanwhile, as far as 36° S. 21° E. in the south-western part of the Indian Ocean, 
there were splendid twilight colours. 

At 4 a.m. on September 3rd, in 7° S. 33° W. the northern horizon was very red, 
and at 7 a.m. the sun was pale blue. At 8°*2 S. 34°*6 W. the air was grey and 
hazy ; but there is no mention of a blue sun. A fiery sky and white sun were seen 
at 3° 6' S. 27° 4' W. The glows reached Cape Town, Africa, and 17° N. 125° W. in 
the Pacific. 

It is plain, so far, that the phenomena did not occur simultaneously in places 
situated on the same degree of longitude, and that they differed greatly in intensity 
at places not far apart. South of the Equator there is little mention of a blue sun, 
but much of a persistent grey haze in the upper air. 

On September 4th the green sun reached as far west as Fanning Island, in 
3° 30' N. 159° 22' W., and the sun was copper-coloured in the afternoon, giving rise to • 
considerable anxiety, while at 16° 5' S. 148°45' W. there was a remarkable sunset glow. 
At 10° 19' N. 161° 21' W., in the morning the sky was covered wJth a thin white 
layer, through which the sun penetrated, and the atmosphere looked yellow and watery. 
Tliis peculiar haze was noticed from this time continuously for many days by the 
captain of the Papa. At 8° 20' N. 155° 28' W., both a green sun and strange sky 
colorations were seen in the evening by the captain of the Jennie Walker. The 
light haze over the sky, and silver sun, seem to have reached as far as Tapiteuea 
(1° 10' S. 174° 50' E.) on this day, or the 5th by Eastern time. 

On September 5th the zone of blue or green sun in the Pacific reached as far 
north as 21° 30' N. for a short time, and southward at least as far as 13° 17' S., 
and in breadth was wider than hitherto. The haze, which was dense at 8° 1' N. 
161° 4' W., was hardly perceptible at 21° 30' N., but the red light seen after sunset 
at the latter point did not show itself at the former. The afterglows now began to 
be noticed in the Transvaal. 

Early on the following day, September 7th by Eastern time, the sun was blue at 
5° N. 163° 6' E., and coppery at the Equator in 172° E., but there is no means of ascer- 
taining how far west and how far north and south the phenomena extended on this 
day. From September 7th to 9th there was a startling redness of the eastern sky off 
the coast of America between New York and C. Canaveral. About the same time the 
red sunsets seem to have appeared in Virginia and the Southern States. 

On September 8th, Eastern time, the haze continued dense in the Pacific. On 
September 8 th, Western time, a red sunset was observed in Florida, and at Chelsea 
and Haslemere in England, but there was no continuance in England of any remark- 
able after-glows. 

On September 9th a greenish sun was seen at 10° 30' N. 122° E., and the sun 

2 T 



II 



318 



THK HON. ROLLO RUSSELL ON THE 



wa% blue or green in Ceylon, in about 8"* N. 88'' 44' R, in lfi| 
17' E., and in 12° N. 51^ K In 37^ 06' S. 40'' 46' W. there was a pa. 
at noon ; and, after G p.m., a very wonderful sunset. In New Z 
174^ 44' R, the fine sunsets began. From September 9th to 12th a 
sun was visible over a great pait of India On September 9tb there weil 
and sunset glows at about 28" N. 80° W, 

There can be no doubt, from a comparison of the data given in tb 
that the blue sun and yellow haze passed roimd the world from east 
gradually widening zone, and that the matter concerned in produciq 
unequally distributed in clouds or streams of different density. The ^ 
twilights were seen only wh*^re the haze was much thinner, either befi 
main cloud of matter covered the sky, or after it had passed, or at its 
northern and southern hordeiu Some places had twilight glows for a 
long betbre they set in regularly ; and these glows seem to have hm 
portions of the main stream breaking off or sinking into diffei*ent cii 
^uch as balloon ascents have proved to exist, at lesser elevations. Tb 
at Ceylon, from August 27th to September 9thj may have been partly 
branch streams, and partly to matter brought at a much lower level 
from the vicinity of the volcano. The after-glow on September 81 
was probably caused by a detached portion of the grea-t body of ujatt* 
passed a little south of it on Heptembei' 2nd* 1 he after-glow noticed ii 
soutliern Englisli counties on September 8tli wuuld be accounted for b 
particles of the main stream as it crossed the Atlantic from August 31st 
2ndj dropping into the anti-trade, and being carried to our shores in 
days. This supposition would agr^ well with the interval shown in 
have elapsed between an eruption in tlie Azores and twilight phenomeni 
Another not impri»bable supposition is that these slight after-glows wi 
the Krakatoa eruptions of May, 1883, for the interval of thi'ee months 
days nearly corrasponds with the interval between the August erupti 
later sky phenomena irj Europe. 

As regards the breadth of the main stream, the edges of which 
fiery after-glows, in the firat circuit of the world it seems to have 
the Atlantic at least from IS'^S, (St. Helena) to at least lO^'or 12' 
west it was conspicuous on September 2nd at 11^ N, (Trinidad), b< 
(Santiago). Three days later, in tbe Pacific, it was seen at 22° N. as 
]»robably extended much further south in the longitude where seen. 
There is no evidence of an increase in breadth after this until the fin 
completed, with the exception of Wellington, New Zealand, 41° S. 174' 
liplendid sunsets were reported as beginning on September 9th, Easten 
j3^ only three days after Hunoliilu. Whether these sunset glows wer^ 
fringe of the main stream passing by> or to an offshoot from it, cannot \n 



GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 319 

The denser part of the main cloud of matter in the first circuit, causing a blue, 
green, or silvery sun, and a yellow or white haze, covered a much narrower area than 
the after-glows. In the Indian Ocean it seems to have extended from Diego Garcia 
to the Seychelles on August 28th— that is, between 20° S. and 5° S., and probably 
some degrees further north; in the Atlantic, between 10° 40' N. and 14° S., and 
in the Pacific between 10° 19' N. and 13° 17' S., excluding a report of a green 
sun of short duration at Honolulu. On the coast of China, at 20° N., a green sun 
and an after-glow were noted on September 10th. A coppery sun was seen at a 
few places only, near the Equator, namely, 1° 20' S., on August Slst, off the west 
coast of Africa; 3° 30' N., at Fanning Island, on September 4th; and about the 
Equator 172° E., on September 7th, Eastern time. A coppery sun had been seen 
at Japan on August 28th with a similar haze of great density, and probably 
much lower in the atmosphere. 

On September 9th, when the main cloud of matter had reached India after a 
circuit of the earth, its breadth appears to have been greater in the northern than in 
the southern hemisphere. A green sun was visible over Southern and Central India 
on September 10th, and in 18° N. 85° 40' E. Meanwhile, phenomena far south in the 
Atlantic showed that a quantity of matter had been left in the track of the great 
cloud, and had drifted southwards. In the Pacific, at 1°"0 S. 165°* I W., the sky was 
still thinly veiled, and after-glows continued at Honolulu. 

In the second circuit a green sun and moon were seen in the Red Sea to about 
14° N. The after-glows were seen as far as 15° N. No green sun is reported from 
the Seychelles or Mauritius. 

On September 12th the first glows reached Muscat, 23° N. 59° E. 

On September 14th, in 15°*2 S. 87°'3 E., there was both an intense red glow 
and a greenish sun. In the Atlantic on September 14th the sun was green as far as 
14° 36' N., but there is no mention of a green sun in that ocean south of the Equator. 
The after-glows were conspicuous in the Atlantic ; and on September 13th the cirro- 
stratus or haze extended to 14° N., resembling what was seen further south on Sep- 
tember 1st. On September l7th the glow was seen in 23° 44' N. and 18° 41' W. 

On September 15th the after-glows extended to South Australia and Tasmania^ 
about 41° S. 

On the 15th and 16th, at Barbadoes, the sun was of various colours. 

On September 18th, at 140° 5' W., the glows extended to 24° N., and at 147° W. 
the green sun was seen as far as 15° N* On the same day, in the Atlantic, at 20° 
N., the sky was luminous. 

On September 20th the glows began to be seen regularly at the Cape of Good 
Hope, and were noticed at 34°-9 S. 22°-4 E. and 49°-9 S. 48° W., at 49° N. 20° 16' W., 
and in London. (The last were probably sporadic cases.) 

They were visible over the northern part of India from September 21st to 30th, 
and at Santiago, Chili, about 33° S. 71° W. 

2 T 2 



320 THE HON. ROLLO RUSSELL ON THE 

On September 22nd the green sun had returned to Southern India after a second 
circuit of the globe, and lasted two or three days as before. After this no well- 
attested observation of a green or blue sun, except at Duem, 14° N. 32° 30' E, (m 
September 24th, when it rose green, and at 9° S. 35° W. on September 28th, when 
it set pale blue, occurs in any contemporary record. 

On September 29th, in 5° 13' S. 35° W., the sun had a whitisli appearance, 
and at 1° 23' N. 41° 5' W. on October 1st the sunrise was very pale. 

During September the glows were seen continuously in the Pacific, between New 
Hanover and the Marshall Islands.* From September 20th to 30th, the twilight 
glows were affecting a large part of the North Pacific, the Indian Ocean, India, and 
the Atlantic, as far south as 31° S., in 39° 35' W. On September 30th, the red 
sunsets are stated to have begun in Brazil, but in many parts they had been long 
visible at that date. Isolated after-glows were seen in Ireland and Surrey, and at 
36° N. 4° W. At Reunion there was a renewal of glows on September 25th. 

From October Ist to 10th the glows extended in the northern hemisphere to 
Shanghai (31° 14' N.), Binninag (29° 36' N. 80° K), the China Seas, India, Arabia, the 
Canary Islands, the Gulf of Mexico, Virginia, U.S. (occasional), Yucatan (20° N. to 
23° 25' N. 33° 15' W.), Florida, Honolulu, and occasionally and feebly to southern 
England. In the southern hemisphere they continued brilliant in Australia, 
Tasmania, New Zealand, the southern Indian Ocean, the Transvaal, and the 
Cape, at Carrizal (north of Valparaiso), Buenos Ayres, and a large part of the Atlantic 
and Pacific. 

On October the 14th they reached Santa Barbara (California), at about 34^ N. 
120° W. ; and on October 15th, Montgomery (Alabama, U.S.A.), at about 32° 20' N. 
86° 20' W. ; and Lisbon and Nice, at about 89° N. and 43° 42' N. respectively. 

On October 19th, Yuma (33° N. 116° W.) and Oakwood (California), were 
reached ; and some bright cloud effects were at this time observed in Surrey. In the 
Kangra Valley, at 32° N., an- aurora-like glow was seen on October 24th. At the 
end of October many places in the southern and eastern States of the Union were 
reached ; and at Charlotte (N. Carolina), at about 35° N. 80° W., the sky was like 
fire on October 30th, During October the glows were seen continuously in the 
Pacific between New Hanover and Honolulu.* 

Many sporadic glows were observed from this date in the United States, and 
a little later in Europe ; and to these belong the magnificent illuminations on 
November 9th, in England. The main body of sky-haze seems to have reached 
about 38° N. on November 15th ; and on November. 2 3rd, the northern States and 
Canada, to about 45° N., and British Columbia, to about 50° N., were affected. 

On November 24th the glows extended as far north as north-west Iceland ; bot 
there is no mention of them in Norway or Sweden, or any other high latitude. They 

• * Nature,' vol. xxix. (1884), p. 259. 



GEOGRAPHICAL DISTIBUTION OF PECULIAR SKY PHENOMENA. 321 

were observed only partially in England and Ireland. On November 25th, however, 
they covered a large part of these islands, and were seen sporadically in France and 
Italy, In parts of Scotland there was a fine display on the 25th. On November 26th 
the whole of England, a great part of France and Italy, Denmark, and parta of 
Germany, especially south and west, were afiected, and they continued magnificent 
in Canada and parts of the United States. Professor Ricc6 mentions that though the 
glows were seen in Italy from November 26th, they did not become very striking till 
the first days of December, that is, four days later than in England. On November 
27 th, glows were seen in south-east Iceland, parts of Denmark, and many places in 
Germany. On November 28th they extended far south and east, including Berlin, 
Constantinople, Angora, the Crimea (end of November), Lesina, and Brindisi, nearly 
the whole of Germany, and Switzerland. On November 29th, to Algiers, Madrid, and 
Carinthia. On November 30th, to Stockholm and Christiania, and to Druskeniki, in 
Kussia. On December 1st the whole of western Europe had most brilliant displays ; 
and they seqm to have reached to Grauheim, 61° 6' N. 8° 35' E., and Upsala, about 
60° N. 18° E., and Malta and Athens, about the same date. In the United States 
they continued, and were brilliantly renewed at Honolulu early in December. At 
Mauritius they continued. During November the glows were seen continuously in 
the Pacific between the Marshall Islands and Honolulu.* On December 2nd they 
reached as far north as Stenkjeer, 64° 1' N. 11° 25' E., and seem to have spread over 
Kussia in the beginning of December. Early in December they were very strong 
in Eiu-ope, North America, the north Atlantic, part of the Pacific, India, Australia, 
and New Zealand. On December 4th the glow reached Crete, and was described 
by telegram as "aurora." On December 7th the glow was intense in North 
America, Spain, and Switzerland, but much fainter in Surrey. On December 11th 
the arrival of a brilliant after-glow was telegraphed from Kiachta, Siberia, in 50° N» 
107° E. ; and on December 16th, in the Crimea, it was taken for "aurora." From 
December 18th to 25th the glows were strong at Vadso, 70° 4' N. 29° 45' E. On 
December 2yth a green sun and red glow is reported from Hankow, in 30° N. 120° K 

From the end of December it becomes impossible to trace the march of the 
glows, for, every part of the globe seems to have been by that time covered, and 
though many alternations in intensity occurred everywhere, no revolution period can 
be distinguished ; and on the whole there was a steady decline, both in duration and 
in brilliancy, in the first months of 1884. 

In April, 1884, there was not, in south-eastern England, the slightest illumina- 
tion of the sky after sunset beyond the ordinary twilight. Recurrences of a moderate 
after-glow on a few days in the summer and autumn were, however, reported from 
several parts of the country. 

In South Africa, glows continued to occur in May ; and in Australia they had 
appai-ently not altogether ceased in July. In the Atlantic several were reported in 

* < Natui-e,' vol. xxix. (1884), p. 259. 



S22 THE HON. ROLLO RUSSELL ON THE 

March, 1884, by Mr. Dove, on the Superh. At Rangoon, which had hitherto been 
little affected, glows were seen from January 22nd, 1884. At Adelaide, Australia, 
they were bright on February 1st, 3rd, 6th, 8th, 11th, I7th, 18th, 24th, 26th, 27th, 
29th. At Honolulu there was some reappearance of the glows in May, 1884, and 
again on August 19th, 1884. 

At Berlin there was an after-glow on June 26th, and at Cartagena on July 9th, 
15th, and 20th. At or near Huntingdon, England, Prof. A. S. Herschel saw the 
white glare and after-glow on September 20th, 1884. In October, 1884, several 
after-glows were reported in England. At the end of March; and in April, July, 
September, and October, after-glows were seen at Cambridge, Mass., U.S.A., and on 
October 13th, 1884, at Vancouver's Island. 

Even in 1885, Professor Riggenbach detected twilight phenomena which, he 
referred to a prolongation of the peculiar condition in the upper air which produced 
the displays of 1883 and 1884. We cannot do better than refer to the fiill detaik 
of observations given in his pamphlet referred to in Section IV., p. 362. 

The Table appended to this Section, and giving the velocity of the smoke-stream 
round the world, shows that a complete circuit was made within the tropics in about 
thirteen days. The same cyclical period appears from the • dates of recurrence in a 
large number of instances. Thus, the blue sun was at its maximum in Ceylon 
on September 9th, 10th, 11th, 12th, 22nd, 23rd, 24th; the interval from August 
27th to September 9th is thirteen days, and from September 9th to 22nd also 
thirteen days. 

The interval between the appearance of an obscured sun at the Seychelles, on 
August 28th, and of a green sun and moon on September 11th, in the Red Sea, is 
fourteen days, and between this and the green sun on September 24th, at Duein, 
thirteen days. 

The interval between the haze and white sun of September 1st, in 9® S. 28° W., 
and the similar haze in 14° N. 26° 4 2' W., on September 13th, is thirteen days; 
and in the eight days from the 5th to the 13th the Captain of the Queen of Cambria 
reports nothing unusual. He remarked, on September 13th, that the haze was like 
that first seen September 1st and last September 5th. 

The blue sun was seen at Trinidad on September 2nd, and at Barbadoes on 
September 15th, an interval of thirteen days. 

The interval between September 1st, when the sun was blue in the morning in 
10° 40' N. 26° 30' W., and September 14th, when the sun set green in ll°-25 N. 
19°'9 W., is thirteen and a half days. 

The interval between the green sun of September 14th, in 11°*25 N. 19°'9 W. 
and 14° 36' N. 27° 2' W., and the blue sun in 9° S. 35° W. on September 28th, is 
fourteen days. 

The interval between the first green sun at 160° W., on September 4th, and the 



GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 323 

appearance of a green sun and moon on September 17th, in 12° 12' N. 146° T W., 
is thirteen days. 

The green sun was first seen at Honolulu on September 5th, and again in the 
neighbourhood of the Sandwich Islands on September 18th and 19th, an interval of 
thirteen days. 

A red sunset was first seen at Mauritius on August 27th, and there was a 
decided increase in brilliancy on September 22nd, an interval of 2 X 13, or twenty- 
six days. 

The maxima of glows at Muscat were on September I3th, 28th ; October 12th, 
27th, intervals of fifteen, fourteen, and fifteen days. 

The interval between the first appearance of an after-glow at Chelsea on 
September 8th, and its re-appearance on September 20th, is twelve days. (The 
interval might possibly have been nearer thirteen days if the equatorial stream in 
the second circuit had not extended much further north than in the first.) 

In October there is no sign of a distinct periodic recurrence of haze or of glows. 

Summary of Part IV., Sectioj^ III. (a). 

The dates in the general list leave no doubt that, on the whole, the tendency of 
the matter causing the twilight phenomena was to spread northwards and southwards 
as well as westwards during the rapid circuit of the blue sun matter from east to west 
within the tropics. The dates for India and the United States show this most 
distinctly. Excluding sporadic glows, due probably to small broken-ofi* masses of the 
great cloud of matter, we find the northern limit near the end of the first circuit to 
have been about 22° N. at Honolulu, or 28° north of Krakatoa, and the southern limit 
about 33° S. at Santiago, or 27° south of Kjrakatoa. Wellington, New Zealand, at 41° S., 
cannot be taken as the southern limit; for Australia does not seem to have been affected 
so early as September 9th. In none of those places which were on the extreme borders 
of the main stream, or beyond it, were the glows regular and continuous from the date 
of the first appearance. Nor could they be expected to show continuity, when we have 
evidence that the cloud causing the rayless sun passed over most places in the tropics 
within three or four days. Towards the end of the first circuit, that is, in the 
Pacific, the amount of matter left behind after the passage of the main cloud seems to 
have been greater than in the Atlantic near the Equator, where tlie sky in most parts 
presented no remarkable appearance after September 5th, until the arrival of the 
cloud on its second circuit. 

At the end of the second circuit, about September 22nd, the glows may be 
roughly stated to have extended from between 20° and 30° N., to between 30° and 
40° S., but their distribution was not regular within these limits. 

While the movement westwards may be presumed to have continued after this 
date, there can be no doubt that a gradual extension northwards and southwards 



324 



THE HON. HOLU) HUSSELL ON THE 



gieatly widened the area over which the red twilights were seen during 
furbnight. They were conspicuous at several places between 20^ and 3< 
southwards as tar as 27^ S., in many different longitudes. Throughout O 
Gulf of Mexico and corresponding latitudes were under the full effect of 
On October 7th NashviUe, about 36"* N., and Buenos Ayres, at 34'' 39' S., bn 
sunBets ; and at Binninag, India, 29° 30' N. 80^ E.j there was a fiery aftel 
7.20 p.m. At the Canary Isles, 28^ N., the glows wai'e cons^icuoua At 
or not far south of it, they were observed by pilots. 

By Octoter 15th the glows had extended still further north ; in 1 
States they had reached 34^ 27' N,, in E\irnpe partially to 43^ 42' N,, in Aj 
unknown latitude^ and in India to Umballa, 30° N. 

By the end of Octol)er the glows h^id spread over the southern , and p 
eastern States of North America, while Australia, Tasmania, New Zeali 
Africa, and Chili, were under their full effect 

Up to about November 23rd glows seen north of about 32"^ to 36"^ 
the most part detached or spomdic* 

But, aWut November 23rd, a very remarkable movement took plaoe^ 
manner that the direction in which the mahi stratum progressed is not clei 
of a large collection of dates, Western Canada, British Columbia, Call 
north-west Iceland, seem to have been first affected, and then in suocessios 
Denmark, France, Italy, Germany, Spahi, Algeria, Austria, Turkey, Rusa 
Siberia, and northern China. To distinguish sporadic from continuous 
easy matter. But a general view inclines us to regard this later raovemeni 
})lace frotu west to ea.«t* An exact course cannot be determined owing to the 
in density and irregularity of outline of the great cloud. Exchiding 
displays^ the glows were seen in the north-western parts of Europe abo 
before they drew attention in the east and south-east. England, aa a 
affected before Denmark as a whole, Denmark before northern liussiai 
Russia before Kiachta, North Ita,ly and Lisbon, parts of France and GeriS 
affected on the 2*jth, south-esist Iceland, and a large part of western 
Europe, on the 27th, part of eastern Europe on the 28th, southern Italy 
about December 1st, 

Over the northern part of North America the direction of movemeni 
appear, for the glows were seen about November 23rd in both east and w« 
can only infer that they were spreading quickly from the south, where the 
been sporadically noti'^;ed. San Franciaco, New Westminster, and Oregon ai 
Ontario, report them as beginning about the same time. On November 
were general in the States. 

Perhcips the most probable supposition is that the main cloud both 
and in Europe was moving from nearly west to east ; at all events^ in thi 
parts, with large offshoots extending from south or south-west to north or 




GEOGRAPHICAL DISTRIBUTION OF PECULIAR SKY PHENOMENA. 325 

On the assumption of the northern limit having heen continuous in the same latitude, 
it would be difficult to account for the eastern States having had glows at the 
same time as the western (while in Europe the east was later by about a week), and 
for England having been the first of European countries to enjoy them in their full 
splendour. 

The movement of the earlier detached clouds, which reached parts of the northern 
States, England, and Russia, between November 8th and 1 1th, is equally uncertain. 
Their structure in England, however, indicated a movement from a point between W. 
and S. 

The structure of the main cloud indicated a motion from S.S. W. to N.N.E., or an 
initial motion from south to north, gaining an eastward drift. Observation showed, 
if anything, a slow motion from west to east. 

A survey of the Qourse of the phenomena of the sunset glows leads us to infer 
that within the tropics the matter causing them moved at about 73 miles an hour from 
east to west, and gradually spread southwards and northwards, becoming thinner 
and mora diffused, so that by the end of a period of six weeks, viz., the 8th of 
October, nearly the whole space included between 30° N. and 45° S. had been subject 
to the phenomena ; and that the motion from east to west became arrested as the 
matter travelled northwards and southwards. Further north and south than about 
30° or 35°, it seems probable that the motion was from south-west and west in the 
northern hemisphere and from north-west and west in the southern hemisphere 
The rapidity of propagation to South Africa and Japan was so great that we can 
hardly doubt the prevalence at the time of a direct upper current in each direction 
at a level below that of the great current which carried the dust from east to west at 
the velocity above mentioned. The march of the glows over N. America and Europe 
at the end of November appears to have been part of a movement of the hazy 
stratum from over the mid-Pacific and mid-Atlantic Oceans respectively, but we 
have no data for affirming that the glows receded from those vast areas at the corre- 
sponding time. From Honolulu, we have a report of an increase in brilliancy on 
November 25th,* and of a prevalence of the glow between Honolulu and Now 
Hanover continuously during September, October, and November ; while the Papa, 
sailing from Apia (Samoan Islands), had nothing of the kind during October 
and November. 

F. A. RoLLO Russell. 

• * Nature,' January 17, 1884. 



2 U 



326 



MR. E. DOUGLAS AECUIBALD 



SECTION m. (d). 

The Conntictton between the Propagation of the Sky Hazi 
accompanying optical phenomena, and the general circulal 
Atmospherk 

By Mr. E. Doug lab Archibald, 

Regarding the prevailing westward extension of the phenomena a 
'26th, 1883, at first along a relatively narrow zone on each side of th< 
seems natural for the smoke of a volcano, situated like Krakatoa, 6 degi 
the Equator, to drift in the direction of the prevailing wind of that \i 
rather than east ; and though we have little direct evidence that the uppei 
near the Equator moves generally in the same direction as the lower 4 
there is evidence that both in the minor and in the major eruptions { 
in 1883 the volcanic emissions (including both the ashes and the finest dn 
farther in a westerly than in an easterly direction, and that the air currei! 
tended in this direction. Thus Mr Verbeek, in * Krakatau,' p. ll,stata 
preliniinary eruptions of May 21st to 23rd, 1883, the sounds were propa 
further (up to 835 kilometres, or 519 miles) in a we-sterly direction, than 
eaat, where they did not appear to extend beyond Poerwakarta, 225 kil(» 
miles) from Krakatoa. < 

Again, at 7 p.tn. on May 23rd, the Dutch steamer Conrad^ wb 
Krakatoa, reportfl the foUowing remarkal>le fact. After mention is ml 
inconvenience being felt from a thick rain of ashes and from sulphur vap 
told that ^' St quelque distance on voyait la fum^e noire couple net, co 
dtait arretde con t re un mur par la mousson de TEst, tandis qu'St FOuei 
s'atendait ^ perte de vue." * i 

Other facts mentioned by Mr, Vereeek support the same conclusia 
falls of ashes on the Madura and at Teloek Betoeng, referred to already^ 
to the west of Krakatoa, contrast strongly with the fact that during the 
there is a total absence of any record of the fall of dust or ashes at the ne 
to the east in Java* 

At Vlakke Hoek, the south-westernmost point of Sumatra, 62 Engli 
west of Krakatoa, '' a rain of ashes commenced to faU on the morning o 
and continued until the afternoon of the 23rd, the moment when the i 
from the east to the north." 

Moreover, Captain Ferzenaab, who furnisherl a report to Mn V^El 
visiting the island and its vicinity on August 11th, said that during all t 
from May 20 th up to that date, by which time the three principal era 
action, the ashes had been blown chiefly in a north-westerly direction 



ON THE SKY HAZE. 



327 



During the major eruptions of August 26th and 27th, a similar dominance of 
westerly over easterly motion is still more noticeable. 

Thus, while at places like Buitenzorg and Batavia, to the east of Krakatoa, the 
darkness was either never complete or lasted only two or three hours, in districts at 
much greater distances to the west, in Sumatra, the darkness appears to have been 
more extensive, more intense, and of much longer duration. 

As the distribution of the ashes was clearly like the darkness, a direct function 
of the direction in which the ejecta were mainly carried, we are prepared to find, 
as was actually the case, that their extent, duration, and thickness were much 
greater towards the west than towards the east of Krakatoa. 

This is plainly shown in the accompanying Tables, I. and II., in which the 
duration of these phenomena at the principal places east and west of Krakatoa, in its 
vicinity are compared, together with their distances from the volcano ; the data, 
with the exception of the distances, being taken from Mr. Verbeek's ' Krakatau.' 

The data for the exact durations of both the ash falls and the darkness are in 
some cases wanting, and the latter is given for only the day in Table II., in one or 
two cases, when by comparison with the shorter definite cases in Table I., it probably 
lasted as long as the corresponding ash fell, or through the night. But notwithstanding 
these lacunae, it is evident that on the west side of the volcano, at a mean distance 
nearly double of that on the east, the duration of the ash fall was nearly four times 
as great, and that of the darkness, in any case, more than double. 

TABLE I. 
Towns or Districts E. of Krakatoa. 





Distance 
















from 


Duration of Darkness and Ashes, ai^d Remarks. 




Name and direction 


Krakatoa. 














from 
















Krakatoa. 




Ashes. 




Darkness. 






English 
miles. 
















Began. 


Ended. 


Began. 


Ended. 


o 
.4 


£. Anjer 


31 


August 26, 
9 p.m. 


? 


12 


August 27, 
morning. 


August 27, 
evening. 


12? 


S.E. Panimbang • . 


37 


August 27, 
morning. 


? 


? 


August 27 


August 28, 
morning. 


12? 


B. Serang 


48 


August 27, 
morning. 


11 p.m. 


17 


All 


day. 


12 


£. Tangerang . . 


79 


August 27, 
10 a.m. 


4i p.m. 


^ 


August 27, 
10 a.m. 


4i p.m. 


6i 


E. Batavia 


94 


August 27, 
11 p.m. 


2 p.m. 


3 


August 27, 
10.30 a.m. 


2 p.m. 


^ 


S. E. Boitenzorg 


100 


August 27, 
11.20 a.m. 


3 p.m. 


H 


August 27, 
10.30 a.m. 


1 p.m. 


^ 


Means . . 


65 


— 


— 


8if 


— 


8tV 



2u2 



328 



SIR. E. DOUGLAS ARCHIBALD 



TABLE II. 
Towns (yr Distncts W. of Krakatoa. 





Distnnce 












from 


Duration of Darkness and Ashes, and Remarks. 




Name aod direction 


Knikutoa. 










from 












Krakatoa. 




Ashoa. 


£ 

1 

67 


Darkness. 


1 




English 
miles. 










Began. 


Ended. 


Began. 


Ended. 


N. and by W. Teloek 


49 


August 25, 


August 28, 


1 
All day(?) 27th; at 10.30, 


12? 


Betoeng. 




evening. 


3 a.m. 




27th, robscurite plus 
noire que la plus noire 
nuit. 




W. by N. Blimbing . . 


60 


August 26, 
6.80 p.m. 


Aagust 27, 
10.30 p.m. 


28 


All day. 


12 


N.W. Semanka 


72 


Auguht 26, 
5.30 p.m. 


? 


24? 


? 

1 


12 


N. W. KroS 


133 


August 27, 


August 28, 


32 


August 27, 1 August 28, , 


22 






3 a.m. 


lla.m. 




10 a.m. 


8 a.m. 




N.W. Bencoolen 


276 


August 27, 
12 a.m. 


August 28, 
11 a.m. 


23 


August 27, 
10 a.m. 


? 


^ 


W. by S. Ship2?er6tce.. 


60 


AufiTUst 26, 
6 p.m. 


p same as 
Blimbing. 


28? 


August 27, August 28, 
all day. 8 a.m. 


22 


Means . • 


108 


— 


— 


32 


— 1 — 


16 



Other incidental remarks show that the intensity, as well as the duration both of 
the ashfall and of the darkness, was greater on the western side. Thus, at Teloek 
Betoeng, at 10.30 a.m. on August 27th, the darkness is described as "blacker 
than the blackest night," and at Kroe the obscurity was "deeper than that of 
night." 

An inspection of the ash-map accompanying Mr. Verbeek's Report shows the 
same preponderance of ashes on the western side. From the absence of land to the 
west of Krakatoa it would appear from the map that the ashes had been carried 
mainly to the north-westward and south-westward, reaching as far as Singapore and 
Benkalis in the former case, and Keeling Island in the latter ; but this may not have 
been so much the case as the chart would lead us to suppose ; for, between these 
points the area is mostly sea ; and while the actual limit of the ashes on the west 
coast of Sumatra was Moeko Moeko, 600 kilometres from Krakatoa, in several places 
up to a distance of 400 kilometres the falls reached a thickness of 20 mm. On the 
other hand, in districts to the north-east and east, such a thickness was not observed 
beyond 100 kilometres from the volcano. We may, therefore, conclude that between 
Moeko Moeko, and Keeling Island, the ashes fell much further in a westerly direction 
than appears from the arbitrary line joining the two on the map. 



ON THE SKY HAZE. 329 

The same conclusion follows from an inspection of his map which represents the 
district over which the finer dust fell on ships traversing the Indian Ocean between 
August 27th and 30th. The form of the area is elliptical, with its major axis in a 
line due west from Krakatoa, which occupies its eastern extremity ; the major axis 
being about 30°, or 2000 miles, in length, and the minor 700 miles north and 
south.* 

Further evidence may be considered to be afforded by the distances at which 
sounds were heard which, as shown by General Strachey's map, Plate XVI., was nearly 
50 per cent, greater towards the W.S. W. than in any other direction. 

It may be remarked, that in the vicinity of the volcano during the eruption, the 
wind at the surface at first blew mostly from the south and west, changing afterwards 
to south-east, and in parts, especially in the neighbourhood of Teloek Betoeng, it blew 
temporarily with hurricane force about the time of the greatest eruption on the 27th.t 
This was, therefore, in all probability, an indraft caused by the rapid ascent of the 
gases and materials ejected from the volcano. 

On the whole, therefore, we have abundant evidence that at lofty altitudes 
over a wide area surrounding the volcano, the atmosphere had a considerable 
westerly motion, during May and August, and that the majority of the materials 
ejected from Krakatoa during the grand eruptions of August 26th and 27th, hke 
those during the minor eruptions in May, were from the first mainly carried in 
this direction. 

That this westerly motion was much swifter in those upper strata of the 
atmosphere in which the finest dust remained suspended, is plain from the high 
velocity of translation of the optical appearances westward round the world ; but 
such velocities as 70 to 75 miles an hour are by no means excessive even for 
cirrus clouds at much lower elevations ; while in the present case, if, as we must 
suppose, the dust which fell on ships in the Indian Ocean had been transported for 
the most part by lower cuj'rents, the velocity above seems by no means out of 
proportion to that indicated by the dates of the falls on vessels for some considerable 
distances to the westward of Krakatoa. Thus, taking some of the best determined 
observations up to August 29th, we get the following rates for the velocity with 
which the dust travelled from Krakatoa, assuming it to have started at midnight on 
August 26th, which being 10 hours before the grand explosion on August 27th, and 
10 hours after the first noticeable explosion on August 26th, is taken as the average 
epoch of commencement. 

Only the rates to ships at considerable distances from Krakatoa have been taken, 
as the nearer ones might have experienced falls from minor eruptions before 
August 26th which escaped notice. 

• See also Plate XXXVI. in this volume. 

t Several trees were uprooted bj the force of the wind on the island of Seboekoe. — * Krakatau,' 
p. 488. 



330 



MR. E. DOUGLAS ARCHIBALD 



Date. 


Hour. 
(Local time.) 


Ship* 


Distance in 

English Miles 

from Krakatoa. 


Mean Velocity of 
Ash Stream in 
Miles per Hour. 


Aug. 28. 
Aug. 28. 
Aug. 28. 
Aug. 28. 
Aug. 28. 
Aug. 28. 
Aug. 29. 


5.30 a.m. 
2 p.m. 
a.m. 
5 a.m. 
2 a.m. 
a.m. 
Noon. 


Salazic. 

Simla. 

Brani, 

Arabella, 

Ccutleton. 

Barharossa. 

British Empire, 

Means • • • • 


888 
1,190 

968 
1,141 

830 

844. 
1,787 


30 
31 
40 
39 
32 
35 
29 




1,093 


34 



Note. — ^These are the distances at noon on the day mentioned in the date column. None of the ressels, 
however, were steamers, and in no case will the distance given differ more than a few miles from 
the actual distance at the time given in the hour column. 

If, now, we suppose that the mean height at which the heavier dust floated, 
which thus fell on the ships was 10,000 feet (which is a fair allowance, considering 
that during the last part of its aerial journey it was travelling with only the moderate 
speed of the air near the surface),t by an application of the formula 

V a/~H 

(where V v, H h, are the velocities and corresponding heights at two upper and 
lower points in the atmosphere) which I had found J to agree best with Dr. Vettin's 
observations of the velocities of different cloud-strata up to 25,000 feet, as well as 
with his own anemometrical observations in the free atmosphere between the ground 
and 1800 feet above it, we shall find that the velocity of 36 miles an hour at 10,000 
feet would be increased to 60 miles an hour at 100,000 feet above the sea, and (see 
Section IV., p. 340) to 64-5 miles an hour at 130,000 feet, which brings it nearly to 
the amount (73'5 miles) that has been calculated from observation. 

We have preliminary evidence of the initial westward trend of the ejected 
material from Krakatoa on Ausfust 26 th and 27th for some considerable distance 
from the volcano, and at a rate nearly equivalent to that required by the succession of 
dates of the first appearances of the coloured suns, cloud-haze, and twilight glowa 

We have no independent observational proof that such currents would be 
continued right round the globe, either temporarily or continuously, but there seems 

* These ships were all west of Krakatoa ; their mean latitude was 5° 24' S., that of Krakatoa 
being 6° 8' S. 

t The direction of the lower wind over the neighbouring sea area during the eruption was between 
S.E. and N.B.— * Krakatau,' p. 149. 

J •Nature,' vol. xxxiii. (1886), p. 95. N.B. — This formula applies better to the higher levels 
than to those near the surface, where the increase is more rapid. 



ON THE SKY HAZE. 331 

to be a recent theoretical investigation by Dr. Werner Siemens on " the conser- 
vation of energy in the earth's atmosphere/' referred to by Professor Kiessling in his 
paper, "Ueber die Bewegung des Krakatau-Rauches in September, 1883,"* in 
which he shows that under the Equator the air which experiences no friction at 
all should acquire a velocity in a direction from east to west of about 142 miles 
an hour. 

K this hypothesis be confirmed by future observation, it may possibly help to 
account for the continued westerly projection of the main mass of material, in the 
present case, at the rate demanded by the dates of the successive first appearances of 
the optical phenomena. 

The observed velocities of cirrus clouds, often amounting, as Rev. W. Clement 
Ley has shown, to over 120 miles an hour, and the general results of Dr. Vbttin's 
observations at Berlin, recently published,! in which the upper cirrus in winter, at a 
height of only 23,600 feet, moves at an average rate of 44*5 miles, favour the notion 
that in a region four times the latter height a temporary velocity of from 70 to 80 
miles would not be anything extraordinary. The only remarkable point about such 
a current as we must assume to have existed on the present occasion, is the constancy 
of the motion over so large a tract of the earth's surface for so long a period, and of 
this we have hitherto had no evidence which can be held to be distinctly corro- 
borative. At the same time there does not appear to be anything arising out 
of the theory, or observation of the general atmospheric circulation, to forbid the 
existence of so constant a current at 100,000 feet or more over the equatorial 
zone. The anti-trade currents do not probably reach this great altitude; if they 
do, they cannot commence to have an easterly trend very near the Equator, for the 
east to west component of the lower trades can disappear at only the north and 
south borders of the ascending trades, where the meridional motion due to the 
equatorial bulge commences, and where the deflecting force due to the earth's 
rotation, viz., 2 n v sin — 

(where n = angular velocity of the earth's rotation, 
= latitude, 
and V = velocity of the air) — 

has some appreciahle value. 

In the central portion of the bulge, between these two limits, there is no reason 
why the air should not move in the same direction as the lower trades, and at an 
enhanced velocity due to the lessened friction. | 

* ' Sitzungsbericlite der Koniglichen Prenssischen Akademie der Wissenscliafieii zv Berlin,' vol. zzz» 
(1886), p. 529. 

t "Die Luflatromungen liber Berlin in den vier Jahreszeiten.'* * Met. Zeitacbrift/ AtigQRt^ 1886. 
X This point is dwelt upon more fnlly in Section VII., p. 426. 



332 MR. B. DOUGLAS ARCHIBALD 

The number of meteorological observatories in the neighbourhood of the Equator 
is still very limited in comparison with its large area, and observations of the movements 
of the upper clouds have been made in far too small a number to form a trustworthy 
basis for any conclusions. The Hon. Ralph Abercromby, in his two recent voyages 
round the world, in which he crossed the Equator several times, noticed the move- 
ment of the upper clouds to be generally from some easterly point ; * but to establish 
the fact that this is always the case would obviously necessitate prolonged obser- 
vation at suitable spots in all parts of this region. 

It may be noticed that, in the Pacific, the zone of equatorial calms reaches its 
widest area during August, the month of the great eruption of Erakatoa, varying, 
according to KERHALLET,t from 135 miles in February to 840 in August. 

Another peculiarity in the transmission of the lighter ejecta in the present case 
which negatively favours the existence of the east to west current over the Equator, 
is the occurrence of limited transmissions in the direction of the anti-trade systems 
on each side. 

If the anti-trade systems were separated by only a narrow belt from one 
another, we should have expected to find most of the material transported towards 
Japan on the one hand, and towards Australia on the other, and hardly any carried 
west. 

The facts, on the contrary, show that only a portion of the material was 
entrapped, as it were, by the ordinary upper return trades ; a narrow line of 
coloured suns and glows appearing in turn at Labuan Island, Fisher Island, and 
Tokio, &c., on the one side in a N.N.E. direction, and dust falling near the 
coast of Australia on the other side J in a S.S.E. direction. Also, if we connect 
the appearances seen at the Cape and Natal with those at Mauritius, it 
appears that, Krakatoa being situated 6® south of the Equator, some of the 
material carried by the main upper current subsequently got caught by some 
subsidiary upper current, which carried it possibly in a parabolic curve as far south 
as the Cape. 

At all events, the stream towards Japan was typically anti-trade in character, 
and the feet that no similar transmissions took place over India or Burmah shows the 
transmission in that direction to have been of limiied width. The velocity was about 
half that of the grand stream which was carried round the Equator from east to west. 

The following table of velocities of the principal and subsidiary streams by 
different computers is inserted for comparison : — 

* * Nature,' May 26th, 1887. The Hon. Ralph Abebcrombt found the highest cirrus coming from 
the east over the north-west monsoon in two different years ; and also, on one occasion, over the south- 
west monsoon in the Gulf of Guinea. 

t * Considerations Gen^rales sur Tocean Pacifique.' Rkclds, ' The Earth and the Ocean/ vol. ii. 

X On board the Meda. 



ON THE SKr HAZE. 



333 





Velocity in Miles per Hour. 




Mr. RussBLL. 


Prof. 

KlESSLINO. 


Mr. Vbebeek. 


General stream round Equator east to west from 
Krakatoa. 

Stream towards Japan . . 

Stream towards the Cape. • • . . • ■ 


76 

Mr. Archibald. 
39-3 


84-9 

44-7 

78 


82-9* 
60t 



On the whole, therefore, it may be said that the facts relating to the general 
westward propagation of the heavier dust, borne by the ordinary upper wind which 
blows from east to west in the Javan area at more than 6,000 feet above sea level, as 
well as those relating to the general and special transmission of the finer dust, accord 
well with the theory that along the Equator, and for a few degrees on each side, the 
principal motion of the air (except near the surface itself) is constantly from east to 
west, and that while the heavier portions of the dust travelling in the lower atmosphere 
were dropped, for the most part, to the west of Krakatoa, the lighter portions 
remained suspended in the higher regions, where the motion is more rapid and per- 
haps more constant, and were carried right round the Equator, certainly twice, and 
perhaps continuously. 

The Rev. S. E. Bishop, of Honolulu, in his original pamphlet on the Equatorial 
Smoke-stream, and in a recent communication,J accounts for the due westward 
propagation of the main stream from Krakatoa, by supposing that the finer ashes 
were ejected to a height of 100 miles, whence, descending by gravitation, and having 
an initial westward lag, they derived a poweifiil initial impulse which drove them 
westwards independently of any current existing at an altitude of 30 miles or more. 

Assuming the material to have been shot up to so enormous an elevation, and 
neglecting friction for the moment, an initial lag westwards of about 26 miles an hour 
would be generated ; but even so, and granting that the material slid down an inclined 
plane with considerable velocity, as the author assumes, would it necessarily continue 
this velocity after arriving at lower levels, or anywhere where the air possessed 
sufficient viscosity to hold it in suspension ? According to Professor Stokes's formula 
as applied to the upper regions of the atmosphere, it appears quite impossible for 
the materials, whether dust or gases, to perform this feat, and we, therefore, seem 
obliged to account or this westward translation only by the hypothesis, already 
suggested, of a current existing at this altitude of the direction demanded by the 



motion. 



* If starting point is made August 26, 2 p.m., velocity = 78'2. 
t From Yokohama alone. 

X * American Meteorological Journal,' Jnly to August, 1886. 

2 X 



334 MR. E. DOUGLAS ARCHIBALD ON THE SKY HAZE. 

Moreover, Mr. Bishop gives no reasons in favour of the material having readied 
this enormous height, other than the extreme violence of the eniption, and the 
fact that some of the heavier materials were shot obliquely to a distance of from 30 
to 70 miles from Krakatoa. 

Mr. Verbeek, in his ' Krakatau,' pp. 127-9, discusses this latter point ; and 
finding the evidence on which the second distance depends very uncertain, estimates 
the maximum height of projection from the former distance, as is mentioned in 
Section IV., p. 379, at about 164,000 feet, or 31 miles — a very different figure 
from Mr. Bishop's 100 miles. 

Again, Mr. Bishop assumes* the stream to stop at the Caroline Islands on its 
first journey ; whereas we find strong evidence of its prolongation, not only for one, 
but two complete circuits of the globe ; the dates of the first appearances in India 
and other regions excluded by their latitude from participation in the effects of the 
stream, as it first issued from the Sunda area in a narrow belt, agreeing with the 
hypothesis of a second revolution of the stream ; and not with the more artificial 
theory put forward by Mr. Bishop, of a much slower difi^sion of the main body of 
material by atmospheric currents, which, to make the dates concordant, must be 
assumed to have travelled towards India at the rate of 6 miles an hour, and to the 
Soudan at 8 miles an hour, a difference of 33 i)er cent, in excess of the former. 

E. Douglas Archibald. 



SECTION III. (c). 

Spread of the Phenomena round the World, with Maps illustrative thereof. 

By the Hon. Rollo Russell. 

The accompanying map, Plate XXXV., gives the dates and sites of as many of the 
phenomena as could be conveniently recorded upon it. The series of small maps on 
Plate XXXVI. show, as far as may be gathered from the scattered observations in our 
possession, the area affected by unusual phenomena in successive periods from August 
26th to the end of November. The dotted lines bounding the shaded portions 
indicate the approximate northern and southern boundaries of the elevated haze 
which gave rise to the conspicuous changes in the colour of the sun or sky. A 
continuous dark line shows a better ascertained limit, and an absence of bounding 
lines, as in IV. and V., signifies a total failure of available data from which any limit 
could be drawn. 

Isolated obsei-vations, such as the two in Ceylon during the week August 27th to 
September 4th, and the appearances seen at the end of August in a narrow stream 
from Java to Japan, are omitted in these maps. In No. I, the dotted line inclosing 

• ' American Met. Journal,' July, 1886, p. 125. 




MO- 2cr 



j/^/? Indiaiv Ocean., 



1 



KrakatocL, Rep Roy. ^oc. Corrv. 



APPROCIMATC DISTRIBUnONOF SKY PHENOMENA BBTweEM AUC.aSANoSEPT. 7,1883. 



APPROXIMATE DISTRIBUTIC 




g ID H O 




10 eO 100 MO »<0 W MO I 






■■-t- 

I 



i ^ 










<ii 


1 










f 















APPROXIMATE OlSTRlBUnOHOFSKYPHENOMEHAFwrn SEPT. 22 to OCT.10,1883. 




APPROXIMATE NORTHERN Ul 



m *t m « a -w ta 




APPROXIMATE NORTHERN UMIT oftw MAIN SKY PHENOMENA xttme END op NOVEMBER 1883. PROGRESS ofthi MAIN SKY PHENO 




ON THE SPREAD OF THE PHENOMENA. 



335 



Florida shows the rather extensive area over which red twilights were seen from 

September 5th to 9th, including probably the West Indian Islands, from which 

obeervations are wanting. In No. VI. the front of the cloud is shown, on successive 

days fix)iA August 26th to September 9th, by dotted lines, the only complete blanks 

occurring during the passage across Central Africa on August 29th, and between 

170'' E. and 135*" E. on September 8th (Eastern time). 

Spread or Blub Sux, Red Glow, akd Sky Haze, during the pour weeks following August 26th, 

2 P.M., Krakatoa time. 

B. = Blue, green, silvery, or obscured sun. H. = A lofty haze or appearance of extensive cirro-stratus. 
B. = A red glow before sunrise or after sunset, or a white or peculiar leaden sky, morning or 
evening. 



Krakatoa to Kokkulai, Ceylon, B. 
„ Mullaittivn, Cejlon, B. 

>» »i »» ■^' 

„ Tokio, Japan, B. 

„ ,, „ 15. • • 

„ Seychelles, H. 

„ „ B. 

„ ,, B. 

„ Mauritius, B. 

„ B^union, B. • • • • 

Natal, B 

„ Cape Coast Castle, B.H. 

yS. 6"E., H. 
„ St. Helena, B. 

10° N. 26° W., H. .. 

10° 40' N. 26° 30' W., B 

12°42'S. 27*18' W.,B. 

Corona, 2° 30' S. 20° W., B. 
„ 1° 19' S. 21° W., B. 

Queen of Cambria, 9° S. 28° W., 

Gibers, 3° 5' N. 27° 6' W., B. 
British Envoy, 13° 33' N. 31° 29' W., 

Maranham, B. 

„ H.B. .. 

Carupano, B. 

Vaiinas, B. . . 

.. R 

S. Christobal, B. . . 
„ B. . . 

Panama, B. . . 
Medellin, B. . • 
Guayaquil, B. 
C. Scmthard-Hurlhurt, 17° N. 125° 

Suverh, 16° S. 148" 45' W., B. . . 
„ 13° 17' S. 148° 46' W., B. 
Jennie Walker, 8° 20' N. 155° 28' W., B 
Fanning Island, B. . . 






Distance from 
Krakatoa, in 
English Miles. 



1,980 

2,009 

2,009 

3,644 

3,644 

3,442 

3,442 

3,442 

3,353 

3,495 

5,084 

7,353 

6,924 

7,486 

9,102 

9,138 

8,948 

8,635 

8,708 

9,067 

9,161 

9,464 

10,250 

10,250 

11,594 

12,138 

12,138 

12,228 

12,228 

12,818 

12,553 

13,116 

15,936 

17,745 
17,711 
17,987 
18,278 



Local Mnm of their 
appearance.* 



4 p.m.,? 27th Aug. 
4 p.m., 27th „ 
6 a.m., 27th „ 
6 p.m., 29th „ 
Noon, 30th „ 
6 a.m.,? 27th „ 
6 a.m., 28th „ 
6 p.m., 27th „ 
6 p.m., 28th „ 
6 p.m., 27th „ 
6 p.m., 28th „ 
6 a.m., 1st Sept. 
6 a.m., 3l8t Aug. 

4 a.m., 30th „ 
6 p.m., 30th „ 
6 a.m., 1st Sept. 

5 p.m., 1st „ 

6 p.m., 30th Aug. 
8 a.m., 31st „ 
8 a.m., 1st Sept. 
6 p.m., 31st Aug. 
6 a.m., 3l8t „ 

6 p.m., ? 30th „ 

7 a.m., 31st „ 
6 a.m., 2iid Sept. 
6 a.m., 2nd „ 
6 p.m., 2nd ,, 
3 p.m., 2nd „ 
6 p.m., 2nd „ 
3 p.m., ? 2nd „ 
3 p.m., 2nd „ 

3 p,m,, ? 1st „ 
6 p.m., 3i*d „ 

6 p.m., 4th „ 

6 a.m., &th „ 

5 p.m., 4th „ 

4 p.m., ? 4th „ 



Intervnl to 
nearest Hour- 



28 

28 

18 1 

74 

92 

19t 

43 

31 1 
55 

31 1 

57 
143 
119 

93 
109 
145 
156 
108 
122 
147 
133 
121 
110 
123 
171 
172 
184 
181 
184 
182 
181 
158 
211 

237 
249 
236 
236 



Bate per 

hour to 

neiirest 

Mile. 



71 

72 

[112] 
49 
40 

[181] 
80 

[111] 
61 

[113] 
89 
61 
58 
80 
84 
63 
67 
80 
71 
62 
69 
78 
93 
83 
68 
71 
66 
68 
66 
70 
69 
83 
76 

75 
71 

76 

77 



* The local time of first appearance lias been assamed to be 6 a.in., where the hoar was not recorded. 

t This valne is probably erroneous. The haze, which seems to have been only slight on the 27th, 
would be due to previous eruptions. The figures thus marked, aud those in brackets in the next 
column, are not included in the subsequent calculations. 

2x2 



336 



THE HON. ROLLO RUSSELL 







Diatance fioin 

Krakatoa, id 

English Miles. 


Local tim« of their 


Interralto 


Bateprr 
)>ourto 






appearance. 


nearest Hour. 


nearest 
MiK 


Krakatoa to Maalaaea, R 


17,976 


5 a.m., 5th Sept. 


249 • 


72 


It 


Honolulu, B.R 


18,094 


5.30 p.m., 5th „ 


261 


69 


»' 


Fapa, lO*' N. 161° 21' W., H. 


18,380 


Noon, 4th „ 


232 


79 


jy 


„ 8°N. icrw., B 


18.3(>9 


6 a.m., 5th „ 


250 


73 


» 


Strong Island, B. . . 


20,818 


6 a.in., 7th „ 
(E. time.) 


276 


76 




Iloilo. B. 


2.3,275 


6 a.m., 9th „ 
4 p.m., 9th „ 


327 

840 


71 


>» 


Colombo, B 


26,713* 


79 


i> 


Glejigoil, 900 English miles E. of 
GallcB. 


25,947* 


6 a.m., ? 9th „ 


329 


79 


>» 


fifcofia, 12" N. 61° E., B 


28,297* 


6 a.m., 9th „ 


332 


85 


>> 


Carola, 1 1°-25 N. 19°-9 W., B. 


3:^,082* 


5 p.m., 14th „ 


467 


71 


f> 


C;weeHo/Ca?n6ria, 14'^ N. 26^42' W.,H. 


33,297* 


2 p.m., ? 13th „ 


441 


75 


>» 


Queen of Cambria, 14° 36' N. 27° 
2' W., B. 


33,275* 


6 p.m., 14th „ 


469 


71 


»» 


Barbadoes, B. 


35,588* 


3 p.m., 15th „ 


492 


72 


»> 


Superb, 12*^ 12' N. 146° 7' W., B. . . 


41.695* 


6 am., 17th „ 


536 


78 


»» 


Colombo, B. . « 


51,446t 


5 p.m., 22nd „ 


658 


79 


}) 


Duem, B. 


53,495t 


6 a.m., 24i;h „ 


693 


77 


»> 


0Z6er«, 9'' S. 35° W., B 


58,730t 


6 p.m., 28th „ 


805 


73 



* Distance ivom Ki*akatoa, pins the circumference of the globe at the latitude of the station, 
t „ „ „ twice the „ 



»> >» »» 



» >» 



Subsidiary Measurements taken from Interveninq Localities. 
B. C. = Blue sun in first-named and Coppery sun in last-named locality. 





Approximate Meridional 

Distance between the 
stations in English Miles. 


Interral to nearest 
Hour. 


Bate per hour to 
nearest Mile. 


Maranham to Fanning Island, B 


7,954 


113 


70 


Panama to Zeaiandia, about 160° W. 


5,496 


68 


81 


5" N., B. 








Canipano' to Papi— 161" 21' W., B. 


6,677 


79 


85 


Papa to Strong Island, B. . . . . . . 


2,464 


45 


55 


Fanning Island to Strong Island, B.H. 


2,624 


36 


73 


Honolulu to Belfast— W 66' N. 87° 17' E., 

B. 
Jennie Walker to Belfast, B 


7,516 


76 


99 


7,889 


103 


77 


C'orotia to Fanning Island, B.C. 


9,560 


113 


85 


„ Guayaquil, B.C. . . 


4,076 


35 


116 


„ „ R.C. . . 


4,076 


49 


83 


Seychelles to Corona, B.H. . . 


5,282 


79 


67 


Queen of Cambria to Huperh, B.H. . , 


8,032 


102 


79 


10° 4' N. 26° 30' W. to 10° 30' N. 122° E. 


14,4U8 


182 


79 


(Iloilo), B. 








Queen of dwibria, 9° S. 28" W., to Queen 


24,271 


288 


84 


of Cambria, 15° N. 23" 42' W., H. 








Guayaquil to Papa, 161° 21' W., H. 


6,602 


78 


72 


Corona to Papa, I" 20' S. 20° W., 10° 19' N. 


9,655 


110 


88 


161° 21' W., H. 








10° 40' N. 26° 30' W. to Panama, B. 


3.610 


87 


98 


Corona to Panama, B. 


4,032 


59 


68 


Seychelles to Carupano, B. . . 


8,149 


128 


64 


„ Maranham, B.. . ,. 


6,870 


80 


86 



ON THE SPREAD OP THE PHENOMENA. 



337 





Approximate Jleridionsl 

Distance between the 
Stations in English Miles. 


Interval to nearest 
Hour. 


Bate per hoar to 
nearest Mile. 


Ardgowan to Seychelles, R 

St. Helena to 16° 5' S. 148° 46' W., R. . . 


2,038 


26 


78 


9,618 


144 


66 


10° N. 26" W. to 17° N. 126° W., R. 


6,666 


103 


65 


Campano to Maalaaea, R 


6,200 


77 


81 


„ Honolaln, R 


6,302 


91 


70 


Seychelles to Maranham, R. 


6,870 


79 


87 


Corona to Fanning Island, R. 


9,660 


129 


74 


British Envoy to 0. Southard-Hurlhurt, R. . 


6.251 


90 


70 


Eamoch, 11° N. 25° 30' W. to Trinidad, 


2,444 


40 


61 


11° N. 61° 30' W., R. 








Bodrigaee, 19° 60' S. 62° 30' E., to St. 


4,476 


63 


71 


Helena, 16° S. 6° W.. R. 








Maranham, 44° W. 2° 30' S., to Jennie 


7,686 


126 


61 


Walker, 8° 20' N. 156° 28' W., R. 








C. Souihard-HurlhHrt to Maalaaea, R. 


2,033 


38 


64 


Seychelles to Canipano, R. . . 


8,149 

• 


140 


68 



From these tables we find that the speed of westward progression of the blue sun 
phenomena, shown by taking an average of the rates in the above list, was 70*4 miles 
an hour for the first circuit of the earth, 76*4 for the second circuit, and 76*3 for the 
first half of the third circuit, taking Krakatoa as the starting point for each distance ; 
and by taking the intervals of time between intermediate points in the first circuit, 
80'1. Seven of the best* data in the first circuit give a rate of 76"3 miles an hour 
from Krakatoa to the various localities. 

The speed of progression of the haze in the sky was t 70 miles an hour for the 
first circuit, 77'2 for the second, and 76 between points in the first circuit. Taking 
two of the best observations— one in 26° 30' W., and the other in 161° W. (the 
Papa)-^the rate between these points appears to have been 80 3 miles an hour, which 
is probably near the true maximum speed. 

The speed of progression of the red fore-glows and after-glows in the first 
circuit was 76 ; or, excluding Natal, as affected by previous eruptions, 74*8, The 
mean of eight of the best observations J gives 72*2 miles an hotu", firom Krakatoa to 
the various localities. For intermediate points the speed was 72 miles an hour 
by the mean of twelve observations. 

The first observation of a blue or rayless sun west of Africa was at Maranham, 
giving a rate of 83 miles ; the first observation of a peculiar hazy or leaden sky 
was that of a German sKip, in 10° N., 26° W., giving a rate of 83*7 miles ; and 
the first unmistakeable appearance of the red glow was at St. Helena, giving a 
rate of 80 miles an hour. These figures nearly agree with the rate (83 miles) given 



• Viz. : Gorona, Varinas, Guayaquil, Superb, Fanning Island, Papa, Honolulu. 

t Excluding t\Le observations on the 27th as probably due to previous eruptions. 

X Viz. : Mauritius, St. Helena, Corona, OJhers, British Envoy, Varinas, Superb, Maalaaea. 



338 THE HON. ROLLO RUSSELL 

by the first blue sun observation at Guayaquil, taking Krakatoa as the starting 
point. The highest calculated rates are obviously the nearest to the true speed, for 
in many instances the phenomena would not be noted till after the condition had 
prevailed for some hours ; and the atmospheric change producing the red glows 
would not be noticed dtu-ing the daylight or night-time. The rate of progression 
of all three phenomena in a westerly direction may therefore be taken as between 
81 and 84 mUes an hour at the maximum; but the main body, causing the most 
conspicuous appearances, travelled at the rate of only about 72 miles an hour in 
the first chcuit, if the date of starting is correct. Possibly the speed of the 
second circuit was somewhat greater, or the matter becoming added to that which 
remained in the subjacent upper air from the first passage more speedily produced 
noticeable glow effects. Moreover, observers may have been more ready to note 
at once unusual appearances. The calculated speed is more reduced in the first 
than in the second and third circuits by assuming the eruption to have occurred 
on the 26th, if the phenomena were really due to the eruption of the 27th; 
so that it is probable that the most conspicuous blue sun phenomena at great 
distances from Krakatoa were produced by the explosions which occm^red early 
on August 27th, and in that case the propagation must have been considerably 
more rapid than that shown by the list. For instance, the rate to Panama would 
be 79 miles an hour instead of 70, supposing the great eruption at 10 a.m. to have 
been the cause of the blue sun. 

Places near the same latitude as Krakatoa and near the Equator were earliest 
affected by haze and solar obscuration. The difference between the rates resulting 
from different places of observation would possibly- be accounted for by the clouds of 
matter from the several explosions between 2 p.m. on August 26th and 10 a.m. on 
August 27th not consisting of a continuous majss but .of streams of unequal density 
and at different altitudes. As the eruptions succeeded each other in a large ninnber 
of explosions, the intensity of which varied, the height attained by the ejecta would 
not be the same throughout. The slight haze seen at Seychelles, Rodriguez, Ceylon, 
and Labuan on August 27th, can hardly be ascribed to the explosions of that day, 
but were more probably due to the eruptions of the night of August 25th-26th, or 
of the 26th, or even of the previous week. 

A very heavy outburst must have occurred about 11.25 a.m. on August 26th, 
as the barometer rose and fell about ^ths of an inch on board the Lennox Cdstle in 
91° E. (see Section 11., p. 269) ; and the eruption sounds heard at Ceylon at 7 a.m., 
which must have originated at about 5 a.m. on the 26th, showed that early on this 
day the volcano was already violently active. 

The influence of an incorrect date at the starting-point is so much reduced in 
the second and third circuits that the rates given by these are probably near the 
true speed. We have thus for the blue sun, second circuit, 76 '4 miles, first half of 
third circuit, 76*3 miles. These rates thus agreeing with the 76*3 miles obtained from 



ON THE SPREAD OF THE PHENOMENA. 339 

the intervals between Krakatoa and points in the first circuit, where some of the 
best observations were made. 

For the sky haze, we get 77*2 miles an hour for the second circuit, compared with 
76 for intermediate points in the first circuit. 

For the red glows there is no definite second or third circuit, but the mean of 
SIX of the best pairs of observations* at intermediate points in the first circuit gives 
71 mil^s an hour. 

From these figures we may infer with some force that the eruption which caused 
most of the blue suns, lofty haze, and red glows at distances beyond two or three 
thousand miles from Krakatoa on the given dates, occurred not on August 26th but 
on August 27th, for in that case the calculated speed of the first circuit approximates 
very closely to that of the second and third circuits and for distances between inter- 
mediate points. 

But there seems to be little room for doubt that the earliest effects in the Atlantic 
and Pacific and at Maranham were in part due to the eruption of the 26th. There- 
fore, it seems undesirable to calculate fi:om all the data on the assumption of the 
phenomena being due to the great outburst of the morning of the 27th ; and the 
initial date is accordingly taken as 2 p.m. on August 26th, though doubtless the 
explosions of that afternoon caused only a part of the effects. The speed of the red 
glows approaches remarkably near to that of the sky-haze, considering that they were 
mostly seen only north and south of the main stream of hazy matter, that is, where 
the haze was less dense and probably slightly less lofty. This close approximation 
to the speed of the main Equator stream from east to west indicates that the red 
glow when first seen was caused by the spread northwards or southwards of matter 
detached firom the main stream at no great distance ; for, a passage through many 
degrees would have been subject to appreciable retardation of the east to west move- 
ment by the slower motion of the earth in higher latitudes. As there is no reason 
to suppose that the process of precipitation of particles from the main stream abruptly 
ceased in the Indian Ocean, the sporadic glgws seen far north and south of the blue 
Bun area during the first circuit would, in all probability, be largely caused by the 
descent of the less finely divided matter into upper currents which would rapidly 
convey it beyond the tropics, and temporarily add to the brilliancy of sunset skies 
in regions unaffected, till long after, by the cloud of much lighter particles com- 
posing the main body of the haze stratum. 

F. A. RoLLO Russell. 

• Namely : St. Helena to 16° 6' S. 148° 45' W. ; 10° N. 26° W. to 17° N. 125° W. ; Corona to 
Fanning Island, Bodrignez to St. Helena ; Trinidad to Honolulu ; and BrUish Envoy to (7. Southard- 
Hurlburt 



340 MR. E. DOUGLAS ARCHIBALD 



PART IV., SECTION IV. 

Diurnal and Secular Variation in the Duration and Brilliancy of the 
Twilight Glows of 1883-84, and the Height above the Earth of the 
Stratum which caused them. 

By Mr. E. Douglas Archibald. 

The height of the stratum which produced the fore and after-glows in 1883-84 
can be approximately determined from the depression of the sun when the ulterior 
margin of each is at some measured angle above the horizon, or on the horizon, or 
from the angular elevation of the zones of maximum brilliancy. Since, in most cases, 
the total duration alone of the phenomenon was recorded, the heights are chiefly 
determined from horizontal observations. 

Before, however, we proceed to exhibit any of the results obtained by this 
means, we must refer to the fact, noticed by many observers, of a secondary as well 
as a primary glow ; the latter lasting usually from 50 to 60 minutes before or after 
sunrise or sunset, while the former lasted in most cases about double this time. This 
circumstance has been thought by some to be a feature peculiar to these sunsets, and 
not hitherto observable; and the following letter of Prof N. Story Maskelyne, 
F.R.S., to 'Nature/ January 24th, 1884, certainly seemed at first to countenance this 
idea: — 

'* Wliat is wortHj of especial interest ia tHe great differenoe between tlie periods of prolongation 
then and now -of tHe illumination of the western sky, showing that the second after-glow of recent 
sunsets is a phenomenon distinct from, and additional to, those belonging to normal sunsets. 

The following table exhibits the two series of observations made in 1855, 1856, 1857, and in 
1883-84 reepectirely :— 



ON THE HEIGHT OF GLOW STRATUM. 



341 







First after-glow or cone of pink light. 


Second 












after-glow 










in 1888-84, 


Date. 


Sunset 






Sets. 


which 


at. 


Appears 
as sunset 


Brightest 




begins as 








the first 






colours 
are fading. 


at. 


Ist series, 
1855-66-67. 


2nd series, 
1883-84. 


after-glow 
sets. 




h. m. 


h. m. 


h. m. 


h. m. 


b. m. 


h. m. 


November 11, 1866 
„ 12, „ 


4 131 
4 14/ 


4 50 


4 57 


5 10 






23, 1855 


, , 




. , 


4 55 






December 7, „ 


3 60 




, , 


4 20 






„ ", » • • 






, , 


4 20 






10, „ 






, . 


4 20 






11,1883 .. 






, , 


• • 


about 4 45 


5 45 


»l A^, „ • • 






• • 


, , 


, , 


5 45 


15, 1856 




4 'is 


4 21 


4 35 






„ 18, „ 






4 20 


4 30 






„ ly, „ • . 


3 60 




« • 


4 30 






24,1883 .. 


3 53 




• • 


, , 


about 5 


6 45 


January 11, 1884 


4 13 




• • 


, , 


„ 5 


5 40 


„ 12, „ 


• • 




• • 


• • 


„ 5 


5 55 


„ 16,1857 


• • 




• • 


4 65 






„ 16, „ 


• • 


4 '50 


^ , 


5 






» •**'>,» • • 


• • 




6 10 


5 18 






„ 26, „ 


, , 




5 20 


6 25 






February 8, „ 


5 




• • 


• • 







The colours associated with the actual sunset are quite in accord in both. 

The first after-glow, or pink cone or dome of light appearing after the sunset colours have nearly 
faded, is also similar in both series ; but its time of setting has been apparently somewhat prolonged in 
the recent observations. 

It is the 1883-84 series alone, however, that shows the second after-glow ; and the duration of this 
strange phenomenon, which I have the advantage of observing over a wide bird's-eye view in North 
Wiltshire, has extended on evenings when it could be well observed to about one hour after the first 
after-glow had disappeared below the horizon. The exact moment of this disappearance has been more 
difficult to determine than in the earlier observations where darkness followed ; as recently the heavens 
and the earth have been re-illuminated just as the natural night would have begun. 

N. STORY MASKELTNE. 
Salthrop, Jcuiuary iSth,** 

When we go further back, however, we find records of certain epochs of sunset 
glows not only equal in duration to those under discussion, but closely resembling 
them in many other details. 

Thus, in the * Bibliothfeque Universelle' (Nouvelle S^rie, XXIIL, 1839, p. 382, 

MM, Necker and De La Rive), a table is given showing the time at which the glow 

disappeared on the high mountains of the Alps. This varied generally from 12 to 45 

minutes after sunset ; but from October 16th to 21st, 1837, it was 1 hour 28 minutes, 

and in June, 1834, a little over an hour. A detailed description of the phenomena, 

2 Y 



342 MR. B. DOUGLAS ARCHIBALD 

as seen near Geneva, says : — "In the period from June to September the glow leaves 
the east quarter 42f minutes after sunset, and from September to December 
30 minutes after sunset. From October to February the time after sunset at which 
the red glow appears in the west averages 35 minutes. It disappears at 59 minutes 
aft^r sunset." 

The maximum duration of 96 minutes in 1837 is as long as the average of the 
secondary glows of the present series, and if 59 minutes is to be considered a primary 
glow, it is just about the same as that of the primaries of 1883-84. 

Similar prolonged twilights and glows are recorded as occurring in 1831 in dif- 
ferent parts of Western Europe and America. Thus : — 

"On the 24th, 25th, and 26th of September [1831], from Madrid to Odessa, 
twilight was prolonged up to 8 p.m., or nearly two hours."* 

Again, in 1846 extraordinary after-glows are recorded as occurring in Switzer 
land from the middle of April to the end of May. 

The durations of four were : — 

90 minutes on May 21st. 
80 „ May 23rd. 

85 „ May 28th. 

45 „ May 31st. 

The first three here evidently correspond to the secondary, the last being pro- 
bably a primary glow. 

Again, in the ' Comptes Rendus' (vol. xlviii., 1859, p. 109), in a description of 
certiiin crepuscular effects witnessed off the coast of Africa in a voyage from France 
to Rio de Janeiro in July, 1858, the following passage occurs, in which a secondaiy 
glow is referred to :— 

" Soon after sunset a redness appeared in the east ; 11 minutes after, a redness in 
the west, above a white sheen. The red band sets when the sun is 11^ 42' below the 
horizon. Then a second * arc rose ' appears in the east when the first is setting, and 
passes to the west without appearing at the zenith, and sets when the sun is 18^ 18' 
below the horizon. Sunrise phenomena were corresponding, but the secondary ' arc 
rose* occurred when the sun was 17"^ 22' below the horizon, and the primary when 
the sun was 10° 50' below the horizon.*' 

Another description of similar phenomena, seen about the same period off the 
east coast of South America by Burkhart- Jezleb, is to be found in * Poggendorff's 
Annalen' (No. 145, 1872). The following is a summary of what has a bearing on 
the present series : — 

"On the east coast of South America, in January, 1856, and in 1857 and 1858, 
a wonderful arrehol^ as it is there called, or twilight^glow, was observed. The place 

• Kaemts's * Meteorology/ Walker's translation, p. 411. 



/ 



ON THE HEIGHT OP GLOW STRATUM. 343 

of observation was lat. 26^ 18' S., long. 30^ 50' W. ; and the phenomena were seen 
also in 1857 and 1858 in Desterro, lat. 28^ S. The arrebol occurred only when the 
air was quite transparent,, as after dew or rain. In June, 1858, it appeared after a 
long absence. It began 14 or 15 minutes after sunset, and ceased 55 minutes after 
sunset. Then a second glow appeared, sea-green and golden, which lasted 1 hr. 
30 mins. after sunset. The glow exhibited a splendid violet near the zenith. At about 
22 minutes after sunset the order of the colours from the zenith was as follows : 
violet, blue (light), green, yellow, orange. At the same lime a mixture of white, 
green, yellow, and red, rose to 40° or 55° in the east. There were fine feathery 
elouds in the sky. Shadows cast by the mTebol lasted 40 minutea At Bahia, there 
was no arrebol for three yeats from 1858 ; but they have there a constant thin trans- 
parent haze, not blurring the outlines of very distant objects. When seen, the 
mai^in of the arrebol passed the zenith at 28 to 30 minutes after sunset. Maximum 
light in the west, 43 to 45 minutes ; yellowish glow, 1 hr. 30 mins. ; white do., 
2 hours after sunset.'' 

The above description of the arrebols of South America is remarkably similar in 
many points to that of the glows of 1883-84, especially as regards the durations of 
the primary and secondary glows, and the zenithal passage of the ulterior margin of 
the former. They appear to have diflfered, however, in one essential feature, viz., the 
order in which the colours were arranged from the zenith downwards, the red or 
purple being uppermost during the first part of the present series, and sinking 
towards the horizon only at the dose of the phenomenon ; while, in the arrebols^ there 
seems to have been no inversion, but only an intensification of the tints which 
characterise an ordinary twilight glow. 

Another peculiarity characterising the present series was the difference in defini- 
tion between the primary and the secondary. 

The Rev. S. E. Bishop, writing to ' Nature,' April 10th, 1884,* says : — 

*' I beg special attention to mj former remark of the ' earth-shadow sharply cutting off ' the upper 
rim of the first glow. This was very manifest in the strong heavy glows of September, showing clearly 
that the first glow directly reflected the sun's rays, while in the after-glow, which had no defined upper 
rim, but continued much longer, the haze reflects only the light of the first glow. This bears on 
estimates of the height of the haae." 

And in a later letter to the same journal, dated June 26th, t he writes as 
follows : — 

** In your issue of April 10th (p. 549) ifl the statement by an observer in Australia that the ' red 
glow was margined by an immense black bow stretching across from north-west to south-east.' 

" I wiRh to say that the above language almost exactly describes the appearance to which I alluded 
on the same page as * the earth-shadow cutting off the upper rim of the first glow.* The * black bow ' 
of the Australian was evidently the shadow of the horizon projected on the baze stratum. In both the 

• * Nature,' vol. xzix., p. 549. 
t * Nature/ vol. xxx., p. 194. 
2 y2 



341 



MR. E. DOUGLAS ARCHIBALD 



above cases the lower surface of the haze was evidently well defined, so that, as the horizon intercepted 
the direct rays of the sun, a well-marked shadow moved westward and downward- Above this black 
rim or bow appeared the secondary glow, produced by the reflection of the sun's rays from that portion 
of the haze surface which was directly illuminated. Very often the second glow was more conspicuous 
and impressive than the first, because it shone against the dark sky of night. 

" In the * Proceedings * of some association I have just read an astonishing estimate of the height of 
the haze as 141 miles, based on the fact that it received the sun's rays one hour after sunset, the fact 
being strangely overlooked that the late reflection was a secondary one.*' 

Another observer, the Hon, F. A. Rollo Russell, has noticed the same 
diflference in the definition of the edge of the two glows, and this observation has 
been more recently confirmed by Professor Ricc6, of Palermo,* who, in his summary 
of the optical eflfects, says : " The contour of the second glow was not definite like 
that of the first." 

The following is a list of those who have observed two distinct glows : — 



List of Observers of two Glows at Sunrise or Sunset 



Name. 


Locality. 


(1) Charles Todd 

(*) Miss Annie Ley . , 

(») E. Divers 

(*) Dr. G. Meldrum 

(6) S. E. Bishop 

(«) Prof. 0. N. Stoddard 

(7) L. Hargrave 

(8) F. A. Rollo Russell 

(»)H. Janesch 

{}^) B. J. Hopkins 

C^) Herr Metzger 

P) Prof. W. Koppen 

(i»)Bucchich 

Q^) Arcimis 

(«)F. Gillman 

0*) Prof, von Bezold 

(17) F. Terby 

(1®) Laugier 

0») 0. Jesse 

(2") W. G. Brown 

(«i) Prof. N. Story Maskelyne 

(*^)J. Aitken 

(^)M.L. Cruls 


Adelaide. 

Ashby Parva, Lutterworth. 

Tokio, Japan. 

Mauritius. 

Honolulu. 

Ohio. 

Sydney. 

Richmond, Surrey. 

Laibach. 

Dalston. 

Flensburg. 

Hamburg. 

Lesina. 

Madnd. 

Madi-id. 

Munich. 

Lou vain. 

Rambouillet. 

Berlin. 

Massachusetts. 

Salthrop, Wiltshire. 

Edinburgh. 

Rio de Janeiro. 



Of these, Messrs. Divers, Bishop, Stoddard, Jesse, Laugier, and Aitken, 
express themselves strongly in favour of the notion that the primary glow is pro- 
duced by the direct rays of the sun, illuminating the particles of matter suspended 
in the atmosphere ; and that the secondary glow is the reflection, by the same 
stratum, of a primary glow which is below the western horizon, 

• * Reale Accademia dei Lincei,' series 4a, vol. ii., January 3, 1886. 



ON THE HEIGHT OF GLOW STRATUM. 



845 



Amongst other reasons for this opinion we note the following : — 

1. The respective durations of the two glows ; the first averaging 54 minutes, 

and the second 96 minutes from sunset until their disappearance on the horizon, or 

from their appearance on the horizon until sunrise. 

The observations from which these preliminary averages are taken are given 

below. 







Daration i 


in Minutes. 




Observer. 


Localitj. 






Date. 










Primary, 


Secondary. 




(») Jesse 


Berlin . . 


50 


120 


Jan. and Feb., 
1884. 


(5*) Bnssell . . 


Bicbmond, Surrey .. 


66 
(Mean of 17 ob- 
servations, Nov. 9 
to Dec. 23.) 


94 
(Mean of 16 ob- 
servations.) 




(-5) Bebenr-Pascliwitz . 


Berlin 


64 


101 


Dec. 18, 1883. 


(**) Bacchich . . 


Lesina 


56 


100 


Jan. 4, 1884. 


(*') Hargruve . . 


Sydney 


48 


98 


Dec. 25, 1883. 


(28)Terby 


Lonvain 


51 


120 


Nov. 27, 1883. 


(») Meldmm . . 


Mauritius 


40 


76 


(Nov.), 1883. 


(«•) Divers 


Tokio 


50 


90 


(Nov. and Dec.) 
1883. 


(»i) Thollon . . 


Nice . . 


55 


90 


Dec. 1, 1883. 


(32) Meldrnm . . 


Maaritius 


38 


77 


Dec., 1883. 


(»«) Gillman . . 


Madrid 


61 


101 


Dec. 4, 1883. 


(")Maskelyne.. 


Salthrop, Wiltshire. . 


55 


105 


Dec. 11-14, 1883. 






67 


107 


Dec. 24, 1883. 






47 


102 


Jan. 11, 1884. 


General means 


54 ' 


96 





The durations alone, while they are sufficiently proportionate to the solar 
depression to serve to illustrate the wide distinction between the two glows, cannot 
be taken to show the exact relation between them. For this purpose we must use 
the corresponding angles of solar depression. 

Excluding Mr. Russell's series and Mr. Maskelyne's, the remaining ten give 
for the ratio of the values of the solar depression at the close of the two phenomena 
the following value : — 1*8 : 1. 

Dr. Hellmann, in his article on the duration of twilight (* Meteor. Zeits.,' 
January, 1884), quotes Dr. von Bezold's article ('Pogg. Ann.,' c. xxiii., 1864), in 
which he says : — The ratio of the solar depression, at the time of greatest intensity 
of both purple lights of the ordinary twilight glow, is 2'2 : 1. He himself found, for 
Spain, a mean ratio of 2*4 : 1, single values varying from 3'4 to 1*8, owing to the 
difficulty of determining the end of the second glow. For the present series of 
unusual glows. Dr. Hellmann found from three good observations, on November 



846 MR. E. DOUGLAS ARCHIBALD 

29th, December 31st, 1883, and January 1st, 1884, a mean ratio of 2'5 : 1 ; and from 
Mr. Eussell's observations, a ratio of 2 4 : 1. Professor Ricxjd in his paper (fre- 
quently quoted from, elsewhere) simply says that the depression of the sun at the 
end of the secondary glow was approximately double that at the end of the primary ; 
from which, amongst other reasons, he concludes the latter to be a reflection of the 
former. 

2. The fact that in the extra-tropics the primary was seen to rise in the east, pass 
overhead about 33 minutes, and set in the west about 54 minutes, after sunset ; and 
that soon after the setting of the primary glow, the secondary, in like manner, rose in 
the east, passed overhead, and sank similarly in the west, about 96 minutes after 
sunset. 

3. That, in cases where cirrus-cloud was present, the glow-stratum was noticed 
to begin to shine between only 20 and 29 minutes later than the cirrus above which 
it floated.* 

4. The re-illumination of the lower clouds, evidently by reflection, when the 
primary glow approached the horizon, and the apparent increase of light (very often 
referred to) when the secondary glow reached its maximum some little time after this. 

5. The fact acutely set forth by AiTKEN,t that the second glow is not visible 
until the sun*s rays have passed out of that part of the air in which the particles are 
small enough to reflect chiefly blue light. 

6. The fact that, even in ordinary circumstances, a second " crepuscular " glow 
has been noticed, which has been unhesitatingly attributed to reflection from the 
primary. 

We quote the following from * Kaemtz Meteorology,' Walker's translation, 
p. 409 :— 

*' When the orepuscular curve, formed bj the shadow of the earth, projected on the high regions 
of the atmosphere, sets in the evening on the western horizon, we may stiU, in very faTonrable 
circumstances, perceive a feeble and whitish light illuminating the sky towards the north-west and 
which sometimes rises to a considerable angular height. This light is incontestably due to secondary 
illuminatLon thrown on the higher points of the atmosphere, by strata of air situated, at that time, 
below the horizon, and directly illuminated by the sun ; the light of this atmospheric space is due 
to rays that have already undergone a first reflection, which M. Biot names ' the second crepuscular 
space.' 

*^ It does not appear that this second twilight can be observed from our valleys ; but on high 
mountains it is very frequently visible. De Saussur£ observed it when on the Col du G^ant ; the light 
attained to as much as 30° above the horizon ; the depression of the sun below the horizon was at the 
time 22"*. M. Bravais observed it on the summit of the Faulhom, 2683 metres (8803 feet) above the 
level of the sea, several times during the years 1841 and 1842.*' 

Then follows a table of M. Bravais's observations, six of which give a mean 

• Showing that it was at no very great elevation in the extra-tropics. 

t Second note on the Remarkable Sunsets, by Mr. John Aitken. ' Proc. Royal Society,' Edinburgh, 
vol. xii., p. 647. 



ON THE HEIGHT OF GLOW STRATDII. 347 

depression for the sun = 18°'5 ; which is about the average depression for the limit 
of twilight. He then goes on to say : — 

" If it is true that the ordinary crepuscular curve exactly coincided with the curve of the passago 
of the earth's shadow out of our atmosphere, this second crepuscular curve ought itself to be inter- 
preted in an analogous manner ; and we might use it with advantage to determine the height of our 
atmosphere."* 

It is evident from this that if the upper regions of the atmosphere were more 
than ordinarily full of dust, or other reflecting matter, this second crepuscular space 
might be rendered more generally conspicuous and coloured than in the cases 
mentioned above. 

There are, besides, many other points noticed by different observers which con- 
firm the same view ; amongst others, one by Aitken in the paper referred to above, 
where he distinctly says that the secondary glow was observed to proceed from the 
same filmy clouds which produced the primary glow ; and, further, that " it was 
always possible to tell whether the second glow would be brilliant or not before it 
made its appearance. If the horizon colours were high up and brilliant then there 
always followed a brilliant second glow, but if they were low and dark no second 
glow followed. There was thus a direct relation between the brilliancy of the sunaet 
colour and the second glow." 

Regarding the re-illumination of the lower clouds by reflection when the primary 
glow was near thd horizon, Aitken says : " As far as I have been able to judge, the 
second glow which illuminated the whole heavens was produced in exactly the same 
way as the second illumination of the clouds." And in connection with this view the 
following letter is important, as it was written before the observer had noticed the 
real existence of a secondary glow. 

The author of this paper, writing to * Nature' on December 20th, 1883, 
said : — 

" On Thursday, December 6th, I witnessed one of these gorgeous sunsets in company with a friend, 
from the top of Rusthall Common, near Tunbridge Wells. Like Mr. Bollo Russell, I noticed that the 
peculiar lasting glow came from a lofty stratum of pale, fibrous, nearly transparent, cirriform haze 
which was almost invisible as the sun set, bnt afterwards came gradually into view, at first white in 
colour, and then gradually changing to orange, pink, and finally red, the change to pink occurring 
at 4.25 and to red at 4.45. 

" We observed also a strange reactionary effect produced by this glow, viz., that long after the red 
tints had faded from the ordinary cirrus in the western sky and from some snow-shower cumuli in the 
east, they were both re-lighted by the glow which had meanwhile increased in the west. 

" On Friday this reflection on to low cloads all over the sky from the undoubtedly lofty stratum in 
the west was more noticeable, and it at once struck me that persons who had not observed the entire 
process of the extinction of the real reflection of the sun by these clouds, and their subsequent re- 
illumination by reflection from the upper glow (as Miss Let terms it), might erroneously be led to 
attribute this secondary illumination to their reflection of direct sunlight. On this ground alone I 

* The whole of this passage seems to have dropped into oblivion. 



348 



MR. E. DOUGLAS ARCHIBALD 



should be rather inclined to accept with a little hesitation the observation on which Professor yon 
Helmholtz bases his calculation, viz., that the clouds which were illuminated directly bj the sun were 
45° above the horizon one hour afler sunset.*' 

The alternative hypothesis which has been suggested, of two distinct strata, one 
of which is about double the height of the other, does not seem to have a particle of 
corroborative evidence in its favour, and is, moreover, d priori, improbable, as there 
seems to be no reason why the reflecting stratum, whether derived from cosmical or 
from terrestrial sources, should occur in two definite layers. 

The failure on the part of many observers to entertain the possibility of a 
reflected primary sunset has led to some very widely and often absurdly divergent 
estimates being made of the height of the reflectmg stratum, and it is evident that 
persons who simply noted the duration of the entire phenomenon, without paying 
attention to its minor details, would miss all those phasal changes which, to careful 
observers like Meldrum, Bishop, Russell, and others, afibrded clear evidence of a 
difference in the source of the light as the phenomenon progressed. 

A glance at the following table, which represents the principal items we have 
been able to collect on this point, will show the main reason for their apparent dis- 
crepancy : — 

7%e Height of the Stratum which Produced the Glow Effects, Estimated by Diffei^ent 

Observers. 



Observer. 



(^) Miss Annie Ley 

(86) N. S. Shaler 

(10) O. Jesse 

(8«)Dr. Galle 

(88) P. Estrelle 

(8») J. Aitken 

(40) Meidinger . . 

(*i) G. A. Him (from noticing glow continue two 

hours after sunset, and assuming it to be the 

effect of direct sunlight). 

(87) von Helmholtz • 

(42) Ch. Dnfour 

(48) Herr F. Pockels (from an obserration lasting 

90 minutes). 
(**) Perrotin and ThoUon (from mean of December 
observations). 

(46) Dinklage (mean of two observations on Decem- 

ber 31). 
(48) B. Brauner (November and December) . . 

(47) Professor Ragona . . . • • • 



Locality. 




Height 


in Feet above Sea 
Level. 


Lutterworth 


• • 




68,6401 


America 


• • 




50,000 


, 


Berlin 


, . 




55,772 




Leipsic 


• • 




52,800 y g 


Portugal 






65,618 


i 


Edmborgh •• 


• • 


aboat 71,280 


• • 




about 36,450 J 




France . . 


• • 




1,640,450 (!) 


Berlin 




40 miles 


or 211,200"^ 


Morges 






229,663 




Brnnswick . . 


•• 




147,640 


^ 


Nice 


• • 




164.045 


►H 


Hamburg . . 


•• 




218,179 


r 


Prague 






264,000 




Modena 


• • 




193,248^ 





* He evidently deduced this height on the supposition that the sun is shining directly on tho 
stititum at 45°, one hour after sunset, as may be seen from his description of the phenomenon in which 
darkness supervenes on the first glow, and " sky was again coloured by a pink or crimson glow." 



ON THE HEIGHT OF GLOW STRATUM. 349 

Now, it will be noticed that the heights in the preceding list, with the exception 
of the abnormal value assigned by M. Hirn, range between two very different groups 
of values— one averaging 57,222 feet, and the other 203,996. It is not possible to 
find out in every case the precise method of calculation employed by the observer, 
but in several, where the duration of glow or the solar depression is given, it is easy 
to see whether the secondary glow was taken to be direct sunlight or not. 

In the first group — 

Miss Annie Ley calculates from primary glow. 

N. S. Shaler, uncertain. 

O. Jesse, from primary at diflferent angles. 

Dr. Galle, uncertain. 

P. Estrelle „ 

J. AiTKEN, assumes secondary to be reflection of primary. 

Meidinger, uncertain. 

In the second group — 

VON Helmholtz assumes dh'ect sunlight all through. 

Ch. Dufour „ „ „ 

Herr F. Pockels „ „ „ 

Perrotin and Thollon, uncertain. 

DiNKLAGE, uncertain. 

Brauner, direct sunlight all through. 

Now, though about some of these there is a little uncertainty as to what exact 
hypothesis was adopted, there is a very strong probability that those in the first 
group were calcidated either from the primary alone or from the primary on the hypo- 
thesis of direct sunlight, and the secondary as a reflection from it ; and the second 
group firom the secondary alone {i.e., from the total duration of the phenomenon) on 
the hypothesis that it was entirely due to direct sunlight. The uniformity of the 
figures in the two groups favours this conclusion, and also the fact that the figures in 
the second group, if converted into solar depression, and treated by the formula on 
the hypothesis of two reflections used hereafter, would approach remarkably close to 
the average of the first group. 

A residt given by the Rev. S. Haughton, M.D., F.R.S., in a paper read before 
the Royal Society of Dublin, January 21st, 1884, shows a similar ratio between the 
heights of the ordinary twilight-producing stratmn on the two hypotheses. 

Thus, for a solar depression = 18°, the height of the twilight-producing stratum 
i