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-LIBRARY
OF THE
IVERSITY OF CALIFORNIA
GIFT OF\
deceived
A c cessions No 2-3
Shelf No.
THE IRISH GAS LIGHT FOR LIGHT-HOUSES— 1O8 Jets.
43D CONGRESS, ) SENATE. j Ex. Doc.
1st Session, ) \ No. 54.
OF A
TOUR OF INSPECTION"
OP
EUROPEAN LIGHT-HOUSE ESTABLISHMENTS,
MADE IN 1878,
BY
Major GEOROE H. ELLIOT,
OF ENGINEERS U. S. A., MEMBER AXU EXGINEEIJ-
SECRETARY OF THE LIGHT-HOUSE BOARD,
UNDER THE AUTHORITY" OF
Hon. WILLIAM A. RICHARDSON,
SECRETARY OF THE TREASURY.
APRIL 24, 1874.— Referred to the Committee on Printing.
JUNE 2, 1874. — Ordered to be printed, together with one thousand
additional copies for the use of the Treasury Department.
WASHINGTON:
GOVERNMENT PRINTING OFFICE.
1874.
TABLE OF CONTENTS.
Page.
Resolution of the Senate of March 30,1874 * 7
Letter from Secretary of the Treasury to the President of the Senate 7
Resolution of the Senate of June 2, 1874 7
Letter from Professor Henry to Hon. H. B. Anthony 8
Extract from Light-House Board Report for 1873 9
Outward voyage, and deficiency in fog-signals on transatlantic steamers 15
The Trinity House, London 18
Fog-signal experiments near Dover, under direction of Professor Tyndall 22
Extracts from Professor Tyuda.ll's report 25
Sir Frederick Arrow's remarks on Professor Tyudall's report 59
South Foreland electric lights , 66
Roman pharos in Dover Castle 72
Examination of the Doty lamp 74
Experiments with lights in Westminster clock- tower 75
Trinity-House depot at Blackwall 76
Improvements in lamps for light-houses 80
Inspection-tour of the North Sea lights of England in the Trinity House steam-
yacht Vestal 99
Iron light-houses off the mouth of the Thames 99
Orforduess lights 101
Depot at Yarmouth 101
Haisbofough lights 104
Experiments at night with Haisborough lights 109
Newurp light-ship 113
Cockle light-ship 115
Spurn Point lights 115
Flamborough Head light 117
Whitby lights ,,.. 118
Souter Point light 120
Coquet light '. 127
Inner Fame Island lights 130
Longstone light 130
'Return to London , 132
Second tour of inspection. — the southwest coast of England 132
Light-house depot at Isle of Wight 132
Saint Catherine light 133
The Needles light... 134
Lights of the Bill of Portland 135
The Start light 135
The Eddystone light 136
Saint Anthony light 137
Plymouth Breakwater light 137
The Lizard lights 139
The Wolf light 140
Rundlestone bell-buoy 144
Seven Stones light-ship 145
Longships light 146
Godrevy light. 148
"The Stones" buoy, off Godrevy 148
4 CONTENTS.
age.-
Holybead light 149
North Stack fog-signal station 155
South Stack light 156
Visit to Commissioners of Irish Lights, Dublin 158
Ho wth Baily light 159
Wicklow Headlight 160
Gas-apparatus for fixed lights 161
Gas-apparatus for intermittent lights 162
Gas-apparatus for revolving lights 165
Gas-apparatus for group flashing- lights 165
Gas-apparatus for triform fixed lights 166
Gas-apparatus for triform intermittent lights 167
Gas-apparatus for triform revolving lights 167
Gas-apparatus for triform group flashing lights 167
Experiments with the triform gas-light i 167
Illuminating powers of gas-lights 169
Cost of gas-light apparatus 170
Cost of gas-light apparatus, (triform) 171
Cost of maintenance of gas-lights 171
Illumination of beacons by gas 172
Wigham's gas-gun 174
Visit to Commissioners of Northern Lights, Edinburgh 175
Stevenson's holophone 179
Visit to lens manufactory of Chance, Brothers & Co 183
Visit to Commission des Phares, Paris 184
D6p6t des Phares of France. 185
M. Reynaud's observations concerning mineral oil 193
Lens-makers of Paris 203
Lepaute's observations concerning light-house burners 208
Light-houses at the mouth of the Seine 215
Pharede THdpital 217
Feu de port at Honfleur 218
Phare de Fatouville '. 219
Phares de la Heve 220
Description of the electric lights at La Heve 226
International exhibition at Vienna 249
Submarine foundations for harbor light-houses 250
Models of light-houses 250
Light-house apparatus 251
Iron tower for fourth-order light 254
Swedish light-houses 257
Austrian fog-horn 261
Osnaghi's reflectors 262
Return voyage 266
Conclusion 267
LIST OF ILLUSTRATIONS.
PLATES.
Page.
Frontispiece : The Irish gas-flame for light-houses 1
I. South Foreland, general plan of light-houses 66
II. South Foreland, ground-plan of engine-house 68
III. South Foreland, lantern and lens at 70
IV. Six-wick Trinity House burner 76
V. Maplin Sand light-house 100
VI. Haisborou'gh, general plan 106
VII. Upper part of English light-house tower 108
VIII. Ventilating window for light-house tower 110
IX. Souter Point, chart of vicinity of 120
X. Souter Point, plan and details of low light-room at 122
XI. Sonter Point, plan of machine-room 122
XII. Souter Point, general plan 124
XIII. Souter point, ground-plan 124
XIV. Souter Point, section of lantern, lens, and low light-room 126
XV. Souter Point, east elevation 126
XVI. Coquet Island, chart of vicinity of 128
XVII. The Longstoue light-house 130
XVIII. The Eddystone light-house 136
XIX. The Wolf light-house 140
XX. Land's End, chart of vicinity of 142
XXI. Comparative sections of rock light-houses 144
XXII. Holmes's fog-horn apparatus 146
XXIII. South Stack fog or " occasional " light 156
XXIV. Howth Baily gas light-house 158
XXV. Howth Baily gas light-house 160
XXVI. Wicklow Head gas light-house 162
XXVII. One-hundred-and-eight-jet burner 164
XXVIII. Twenty-eight-jet burner „ 168
XXIX. Triform burners 172
XXX. Triform lenses 174
XXXI. Swedish light-ship 204
XXXII. Revolving catadioptric apparatus for light-ships 206
XXXIII. Burners of French light-house lamps 208
XXXIV. Interior adjustments of level in mineral-oil light-house lamps 21'>
XXXV. Exterior adjustments of level in mineral-oil light-house lamps 212
XXXVI. Mineral-oil lamp of 1845, Lepaute's gas-burner, Doty lamp 214
XXXVII. La He ve, elevation and general plan 220
XXXVIII. La Heve, ground plan of machine-room . , 226
XXXIX. La Heve, section of machine-room 230
XL. La Heve, front elevation of magneto-electric machine 232
XLI. La Heve, side elevation of magneto-electric machine 234
XLII. La Heve, plan of magneto-electric machine ...... 238
XLIII. La Heve, details of magneto-electric machine 240
6 ILLUSTRATIONS.
Page.
XLIV. La Heve, switches 242
XLV. La Heve, regulators 246
XL VI. Lanterns and lenses for electric and oil lights at Cape Grisuez .... 248
XLVII. Submarine foundation for harbor light-houses 250
XLVIII. Lens for electric light 254
XLIX. Iron tower for fourth-order light 256
L. Austrian fog-trumpet 260
FIGURES.
No.
1. Roman pharos in Dover Castle 73
2. Douglass gas-burner 79
3. Five-gallon oil-can 91
4. Chimney-gauge 90
5. Buoy-finder at Yarmouth 102
6. Bilge-keels of light-ships 104
7. Red cut, Spurn Point 116
8. Fastening for red panes, Whitby 119
9. Lamp-guard ' 119
10. General view of establishment at Souter Point . 120
11. Lens and lanterns, Souter Point 124
12. Low light-room, Coquet Island 128
13. Filling oil-butts at Saint Catherine's 134
14. Red light, Plymouth Breakwater 138
15. Rundlestone bell-buoy, off Land's End 145
16. Three- wick lamp at Holyhead : . „ 150
17. English and American lanterns 154
18. Faraday's wind-guard, North Stack 155
19. Diagram illustrating revolving intermittent gas-lights 163
20. Stevenson's holophone, vertical section . 180
21. Stevenson's holophone, front elevation 180
22. Mineral-oil test, (areometer) 188
23. Mineral-oil test, (flashing point) 188
24. Sautter's lantern for electric light 207
25. La Heve, plan of electric light-room 222
26. La Heve, vertical section of electric light -room 223
27. La Heve, lens for electric light , 224
28. Swedish light-house, details 257
29. Swedish light-house, details 257
30. Osnaghi's reflector for flashing light 262
31. Osnaghi's reflector for fixed light 265
IN THE SENATE OF THE UNITED STATES,
March 30, 1874.
Resolved, That the Secretary of the Treasury be directed to transmit,
for the information of the Senate, the report of Major George H. Elliot of
his inspection of European light-house establishments.
Attest:
GEO. C. GORHAM, Secretary.
TREASURY DEPARTMENT,
Washington, D. C., April 23, 1874.
SIR: I have the honor to transmit copy of a letter from Professor
Joseph Henry, Chairman of the Light-House Board, dated the 22d in-
stant, covering the report of Major George H. Elliot, Engineer Secretary
of the Light-House Board, of his tour of inspection of the light-house
establishments of Europe, submitted in response to the resolution of
March 30, (United States Senate,) directing the Secretary of the Treas-
ury to transmit said report for the information of the Senate.
I am, very respectfully,
WM. A. RICHARDSON, Secretary.
Hon. M. H. CARPENTER,
President United States Senate pro tern.
TREASURY DEPARTMENT,
OFFICE OF THE LIGHT-HOUSE BOARD,
Washington, April 21, 1874.
SIR: In compliance with Department letter of the 1st instant, trans-
mitting copy of the resolution of the Senate of the United States, direct-
ing that "the report of Major George H. Elliot of his inspection of Euro
pean light-house establishments" be forwarded to that body, I have the
honor to enclose Major Elliot's report, as directed.
Very respectfully,
JOSEPH HENRY, Chairman.
Hon. W. A. RICHARDSON,
Secretary of the Treasury.
IN THE SENATE OF THE UNITED STATES,
June 2, 1874.
Resolved, That the report of Major George H. Elliot of a tour of inspec-
tion of European light-house systems be printed, and that one thousand
additional copies be printed for the use of the Treasury Department.
Attest :
GEORGE C. GORHAM, Secretary.
TREASURY DEPARTMENT,
OFFICE OF THE LIGHT-HOUSE BOARD,
Washington, May 25, 1874.
SIR :' I beg leave to call your attention to a report presented to the
Senate of tbe United States, by the honorable the Secretary of the
Treasury, from the Light-House Board, by Major Elliot, of the Engineer
Corps.
In the year 1872 the head of the light-house system in Great Britain
sent a commission to this country to examine and report upon the fog-
signals which had been adopted by the Light-House Establishment of the
United States, and in return for the courtesy they received they invited
the Light-House Board to send an agent, who would receive facilities
for obtaining a knowledge of the later improvements in regard to aids
to navigation which had been adopted in Great Britain.
In accordance with this invitation, the Light-House Board sent Major
Elliot, its engineer-secretary, to obtain the desired information.
The report now before the Senate contains a full account of all the
latest improvements in regard to aids to navigation both in England
and in France. It therefore consists of matter of great value to the
light-house service, and I beg leave to request that you will advocate
the resolution now before the Committee on Printing.
The document will not only be required for immediate use by the offi-
cers of the Board in this city, and also by those in the various districts,
but will be of continued use for years to come.
I have the honor to be, very truly, your obedient servant,
JOSEPH HENEY,
Chairman.
Hon. H. B. ANTHONY,
United States Senate.
EXTRACT FROM THE REPORT OF THE LIGHT-HOUSE BOARD TO THE
SECRETARY OF THE TREASURY FOR THE FISCAL YEAR ENDING 30iH
JUNE, 1873.
The Light-House Board, during the past year, desirous of acquainting
itself minutely with any improvements which of late years may have
been introduced into the light-house service in Europe, obtained the
sanction of the honorable the Secretary of the Treasury to commission
Major Elliot, of the Corps of Engineers of the Army, and engineer-
secretary of the Board, to visit Europe and report upon everything
which he might observe relative to light-house apparatus and the man-
agement of light-house systems. He has lately returned, after having
gathered information which will prove of importance in its application
in our country, as will be evident from his preliminary report.
Major Elliot was everywhere received with marked cordiality, and
every facility was given him to inspect the various coasts and systems
of administration, of which full information was furnished him, together
with the drawings and models necessary for a perfect acquaintance with
the latest improvements which have been adopted in Great Britain and
on the continent.
The special thanks of the Board are due to His Eoyal Highness the
Duke of Edinburgh, the master ; to Sir Frederick Arrow, the Deputy
Master, and the Elder Brethren of Trinity House, for the warmth of
their reception and the marked distinction they conferred upon him as
the representative of the Board ; and to M. Leouce Reynaud, Inspector-
general of the Corps des Ponts et Chaussees and Director of the French
light-house service, for his efforts to make the visit of Major Elliot
profitable to his country and agreeable to himself.
" TREASURY DEPARTMENT,
" OFFICE OF THE LIGHT-HOUSE BOARD,
" Washington, September 17, 1873.
" Professor JOSEPH HENRY, L. L. D., Chairman :
u I have the honor to make a preliminary report of my journey of in-
spection of the light-house establishments of Europe, which I have made
by direction of the Board, with the approval of the honorable the Secre-
tary of the Treasury, and from which I returned a few days since.
" 1 sailed on the 30th of April, and, after a pleasant voyage, reached
Liverpool on the 10th of May, observing en route the light-houses on the
Irish coast, and the light-ships and buoys on the approaches to Liver-
pool.
" On the 13th of May I arrived at London, and was cordially received
by Sir Frederick Arrow, the Deputy Master, and the Elder Brethren of
the Trinity House, which has charge of the lights of England and a su-
pervisory control over those of Scotland and Ireland. The Trinity House
kindly ottered me an opportunity of making a tour of inspection of t!;<v
light-houses, &c., on the coasts of England in the steamers which were
about to take the annual supplies, and at the first session after my ai-
10 EUROPEAN LIGHT-HOUSE SYSTEMS.
rival a delegation of the elder brethren was appointed to accompany
me.
u I remained in London some weeks to take advantage of this oppor-
tunity, and in the mean while my time was occupied in inspecting the
depots, lamp-shops, photometric test-rooms, &c., belonging to the Trin-
ity House $ also plans of light-houses, lenses, and other optical appa-
ratus used on the coasts of Great Britain.
" In company with Professor Tyndall, the scientific adviser, some of the
Elder Brethren and the engineer of the Trinity House, I visited Dover
to attend the inauguration of fog-signal experiments, which, under Pro-
fessor Tyndall's direction, are now being carried on at an experimental
station on the cliffs near the great electric lights of South Foreland. The
light-house authorities of Great Britain are fully alive to the necessity
for powerful fog-signals, and are anxiously seeking to find the best ma-
chine, not only to inform the mariner enveloped in fog of his approach
to the coast, but, by distinguishing characteristics of sound, to indicate
to him on what part of the coast he is. The Board will remember that
Sir Frederick Arrow and Captain Webb, of the Elder Brethren, visited
the United States during the summer of last year to be present at some
of our experiments with the steam-whistle, the horn, and the siren at
Portland Harbor. I think the Board has been impressed that on coasts
where fog is habitual, as those of New England, California, and some of
the great lakes, fog-signals are fully as important as lights, and the
English seem to be approaching a similar conclusion.
"Professor Tyndall told me that he intends to make an exhaustive
series of experiments with all fog-signals now in use, to determine the
best. Both he and the Elder Brethren are especially pleased at the
action of our Board in sending an American siren for use in the Dover
experiments. In these experiments the signals are observed from sev-
eral vessels cruising in the Straits of Dover, at different distances from
the fog-signal station and under varying conditions of wind and weather.
The signals tested when I was at Dover were a steam-whistle, an air-
whistle, and a trumpet, very much like the American invention of Da-
boll, but patented by Professor Holmes, and in use at several English
light-stations, The experimenters have since included a cannon and our
own siren. The experiments are not yet concluded, and Sir Frederick
kindly promised to inform me of the results.
"The delay in London gave me an opportunity of examining the lamps
invented by Mr. Douglass, the distinguished engineer of Trinity House,
which present improvements of the greatest importance as regards both
the British lights and those of other countries. Not only is the bril-
liancy of the flame very much increased by ingenious methods of pro-
moting combustion, but the consumption of oil is actually decreased.
In British light-houses and on the continent colza-oil is generally used,
though, for the sake of economy, mineral oil is being rapidly substituted
for it, and the French government has made an order for a general change
to mineral oil in all the light houses of the republic.
"When the Trinity House tender had been made ready, I embarked
with two of the Elder Brethren (Admiral Collinsou, C. B., and Captain
Weller) to inspect the British lights on the shore of the North Sea, and
visited nearly every one on the coast from the mouth of the Thames to
the Tweed, (the boundary of Scotland,) including the gas-light at Hais-
borough and a new electric light at Souter Point below the river Tyne.
At Haisbprough the gas-light was established for experimental com
parisou with an oil-light a few hundred yards from it, there being two
towers, as at Cape Ann on the coast of Massachusetts. At Souter Point
the electric light is necessary, because the coast near the Tyne is euvel-
EUROPEAN LIGHT-HOUSE SYSTEMS. 11
oped by a dense volume of smoke, produced by the immense number of
manufactories on the river between Shields and Newcastle.
" I had excellent opportunities for testing the different varieties of
lights in all kinds of weather, and particularly the gas and electric
lights ill fog. I was especially shown the system of marking the posi-
tions of rocks and shoals by means of what Trinity House calls " red
cuts," i. e. by covering proper sections of the dioptric apparatus with
red glass screens; and at different places on the northeast coast of En-
gland I made several boat-excursions at night to test the utility of the
system.
"After my return from the inspection of the northeast coast I embarked
with Captain Webb, of the Elder Brethren, at Portsmouth, and in-
spected the light-houses on the Isle of Wight and the southern coast,
and passed around Land's End as far as St. Ives, on the west coast of
Cornwall, visiting the celebrated light-house on the Wolf Rock, off
Land's End, which is the most recent and difficult of all the English
examples of light-house engineering. I regretted that I could not land
at the Eddystone light-house, but the sea, although usually not so
dangerous as at the Wolf, was too heavy when I passed it to make a
landing practicable.
" Besides the light-houses on the coast, I particularly observed the light-
ships and the system of buoyage ; and I will here mention that the En-
glish use revolving apparatus in their light-ships in many cases, and they
are found much more useful than fixed lights. I would recommend to
the immediate consideration of the Board the propriety of distinguish-
ing in this way some of our numerous light-ships off the coast of Massa-
chusetts and in Long Island Sound.
" The English also find no difficulty in using fog-signals operated by
hot-air engines in their light-ships, and I saw several, in one case hear-
ing the signal distinctly at a distance of eight miles.
"From England I went to France, and had conference with M.
Keynaud, VInspecteur General des Fonts et Chaussees, and director of the
French light-house service, and M. Allard, the chief engineer, who
is in charge of the office of the Commission des Phares ; also with the
three lens-manufacturers of Paris.
" I was much interested in seeing our own optical apparatus in all stages
of its manufacture ; in learning the modes adopted by French engineers
of testing the lenses, burners, and mineral oil ; and in examining the
most complete depot des pliares in the world, where are shown examples
of all stages in the progress of the science of light-house illumination,
from the first efforts of FRESNEL, inventor of the system which bears his
name, to the latest improvement of the present time.
"I visited the lights at the mouth of the Seine, and the double electric
lights of La Heve at Sainte Adresse, near Havre.
"I afterward proceeded to Vienna and examined the light-house appa-
ratus at the industrial exhibition, consisting of models, drawings, and
photographs of light-houses from different countries, including our own
A package of these, which I made up a short time before I went to Eu-
rope, I was glad to learn, on my return, obtained a diploma of honor.
"After returning from Vienna I visited several light-houses on the
coast of Wales, including two very interesting ones, that at Holyhead
and one at the " South Stack."
"The first-named, a new one, though quite ready, was not lighted until
some days after my inspection ; it combined all the latest improvements
of the English in regard to lens, lamps, and lantern.
"At South Stack is a light which is lowered down the cliff in foggy
12 EUROPEAN LIGHT-HOUSE SYSTEMS.
weather when the light is obscured by fog and it is clear below, a plan
which I had before thought of as applicable to our lights on the elevated
cliffs of the Pacific coast.
u I also visited Ireland and Scotland, the former by special invitation
from the Board of Commissioners of Irish Lights, and I had an excellent
opportunity of seeing two of the light-houses (Howth Baily and Wick-
low Head)" where the illumiuant used is gas, of which Professor Tyn-
dall when in the United States, expressed so favorable an opinion and
which has been applied only by the Irish Board, except in the case I
have mentioned, viz, the experimental light at Haisborough, on the east
coast of England.
" These gas-lamps can be increased in an instant, when the weather
becomes thick or foggy, from twenty-eight to forty- eight, sixty-eight, or
eighty-eight, even to one hundred and eight jets for dense fog, and the
inventor, Mr. Wigham, of Dublin, exhibited to me apparatus for pro-
ducing a light from three hundred and twenty-four jets in the same lens
apparatus.
"At Edinburgh I visited the Board of Commissioners of Scottish Lights,
and had an interesting and instructive interview with Mr. Thomas Ste-
venson, engineer of the Board and a member of the family of celebrated
Scottish engineers.
ul also visited the very extensive manufactory of light-house lenses of
Chance Brothers & Company, near Birmingham, who are the furnishers
or light-house apparatus to the Trinity House, and who also supply in
a large degree the Irish and Scottish Boards, as well as India, China,
and South America. Chance Brothers claim that their optical appa-
ratus is superior to the French, and they certainly have a great advan-
tage in having for the constant supervision of their work a gentleman
of high scientific attainments.
. " I carried with me a special letter from the honorable the Secretary of
State to the ministers and consuls of the United States in Europe, and
I received every facility and courtesy from them and from the officials
of the countries which I visited.
"I have full notes of my inspection, and at an early day shall have the
honor to present to you a detailed report of what I saw differing from
our own system.
" In closing this preliminary report, I will say that the great questions
which are occupying the attention of the light-house authorities of
Europe, and in which the different establishments are in competition
with each other, are :
" What is the best illuminant f and
"What is the best means for producing the most perfect combustion ?
"I will only add that while the British and French systems are neces-
sarily very much like our own, I saw many details of construction and
administration which we can adopt to advantage, (and which I shall
exhibit in my detailed report,) while there are many in which we excel.
Our shore fog-signals, particularly, are vastly superior both in number
and power. They are in advance of us in using both the gas and elec-
tric lights in positions of special importance, in the use of azimuthal
condensing prisms for certain localities ; in the character of their lamps;
in the use of fog signals in light-ships ; in their light-ships with revolv-
ing lights, and, more than all, in the character of their keepers, who are
in service during good behavior until death or superannuation, who are
promoted for merit, and whose lives are insured by the government for
the benefit of their families.
UI am much indebted to Mr. Paul J. Pelz, chief draughtsman to the
EUROPEAN LIGHT-HOUSE SYSTEMS. 13
Board, who accompanied me by its permission and with the approval
of the honorable the Secretary of the Treasury, as my secretary, and
who has made many sketches for the illustration of my report, and who
has, in other ways, been of much assistance to me in the execution of
the duty assigned me.
"Very respectfully,
"GEOKGE H. ELLIOT,
"Major of Engineers U. S. A., Engineer- Secretary."
REPORT.
OUTWARD VOYAGKE.
As stated in the preliminary report of my journey of Date of sailing.
inspection of the European light-house establishments, I
sailed from New York in the steamship Cuba, of the Canard
line, on the 30th of April, 1873.
During the voyage I had many interesting conversations conversation
with the commander, Captain McCauley, in regard to the McCauiey apcon"
lights of the United States, France, and England. In ref- SniightsAmeri'
erence to our own lights he stated that they were in general
satisfactory to mariners, and had been of great service to
him 011 many occasions, during his long service in the
Cunard Company, especially in running between Boston
and New York and between Halifax and Boston.
With respect to brilliancy, the English and American Brilliancy of
lights are, in his opinion, about equal, but those of thefr^ceh,randaEnl
French he considers superior to either.
He said of the electric lights, of which the English and Electric lights
French have several, that they penetrated fog much more1*6
successfully than the common oil-light, and aids to naviga-
tion in fog are, in his opinion, vastly more important than
for fair weather.
Our fog-signals he praised highly, saying that the steam- Fog-signals of
whistle at Cape Ann and the siren at Sandy Hook had fJ marfuers" a
often been of great service to him, and he confidently relied
on hearing them at distances of from six to eight miles. He
thought it would be much to the interest of commerce if the gh
British government would place similar signals at impor-
tant points, as the channel approaches to Great Britain
were nearly as much subject to fogs as is our eastern coast.
Our Nantucket Shoals he considered to be badly lighted, insufficient
and called my attention to the fact that on the coasts of ISetlholi^11
Great Britain, in similar localities, light-ships are placed
at distances of ten to twelve miles apart ; such I found
afterward to be the case. He thought a light-ship should Light-ship need-
be placed off the Eose and Crown Shoal, (which is due east Sown sho2i.aud
from Saukaty Head, on the Island of Nantucket,) so that a
vessel could take a course to it from the Highlands (Cape
Cod) light, and thence to the Nantucket New South Shoals
light-ship, which he thought should be moved farther out.
N: HI:. —The inoro important points to which attention is called in
this report are noted iri the concluding pages 267 to 272,
16 EUROPEAN LIGHT-HOUSE SYSTEMS.
Meeting with On the fifth night out from New York (the night of the
steamer on ?STew- ,,,„-..-» i • IT r* *
Banks 4th of May) we met a steamship on the Banks off New-
in a thick fog. founclland? but tnere being at the time one of those dense
fogs prevalent at some seasons of the year in that part
of the Atlantic, we did not see her, and only 7cnew of her
proximity by the sound of her whistle, a fact which impressed
importance of me with the importance of powerful fog-signals on the
t°rgaSngsDatsi antic steam ships plying between America and Europe on this
much-frequented track.*
Danger of coi- I11 addition to the large number of steamships the num-
Sdl°duringVges!~ ber of sailing- vessels is very great, and the tales of narrow
escapes from collision, especially with fishermen anchored
on the Banks, which one hears while (enveloped in dense
fog) he is steaming along at a high rate of speed, very much
impair the confidence which is naturally inspired by vessels
like those of the Cunard line and commanders like Captain
McCauley ; for it is evident that want of efficient fog-signals
cannot be compensated for by strength of ship or skill of
i n s nfficiency officers. The whistles in use are, I am told, frequently in-
ot whistles in use J
on steamers. sufficient in power, and, being placed abaft the foresails and
in front of the great smoke-pipes, are in such positions that
the sound-shadows often cover the precise directions in
which it is most essential the warning should be conveyed.
Position and I am of the opinion that not only the position but the kind
shouhf sife of fog- signals to be used in transatlantic steamers should
be regulated by a joint commission of the governments in-
terested, and that, before deciding these questions, not only
the whistle, but the Daboll trumpet and the siren which we
use at our fog-signal stations on shore, as well as the Aus-
trian fog trumpet, (shown in Plate L,) should be considered.
As the power necessary to operate these signals is on
these steamships always at hand, it is not, as in the light-
house service, a question of cost of maintenance, but the
questions to be decided on are :
Questions to be First. What is the most efficient instrument for the pur-
detcrmined.
Second. What is the most advantageous position practica-
ble for it?
he?tupositio0nnfor Ttlis Position? it is evident, must be one in no way inter-
steamer's fog-sig-fering with the management of the sails and rigging, and
where no danger exists of the signal being carried away by
the sea.
* From information derived from, my friend, Mr. George W. Blunt,
of New York, and from other sources, it appears that on an average from
eight to ten steamers cross the Banks every day going from America
to Europe and vice versa.
EUROPEAN LIGHT-HOUSE SYSTEMS. 17
The question of ship-lights should also be determined by ship lights.
the same commission, and I have no doubt the magneto-
electric light, which I believe has been spoken of before in
this connection, and which is fully described in this report,
will have favorable consideration, since the steam-power
necessary for operating the magnetic machines is constantly
available.
On the morning of Friday, the 9th of May, we made rhe
southwesterly point of Ireland, and had a good opportunity
'of seeing the important light-house on Fastnet Eock, off Fastnet iiock
Cape Clear. This tower, having nearly vertical sides, which u
spread with a curve near the base, is 92 feet high, and,
together with the appendages, presents a very picturesque
appearance, being surrounded by a high retaining-wall,
necessary, apparently, for the formation of a platform large
enough for the establishment.
The lantern has the vertical sash-bars introduced into
our service from the French. A broad band of red con-
trasts strongly with the color of the main body of the tower,
which is built of iron.
As the Cuba steamed along the south coast of Ireland,
and from two to four miles distant from the shore, a good
view of the neat light-stations was afforded.
A very interesting one was the Old Head of Kinsale with oia Head of
Kinsale light.
its tall tower, on which two red bands distinguished it as a
day-mark.
Each of the stations appears to have capacious grounds
walled in with stone, and all are neatly whitewashed. The
buildings connected with light-houses are generally of one
story, covering a large area. We passed Bally cottin light, . Bali. v cot tin
which stands 195 feet above the sea, and when we stopped lf
at Queenstown to deliver the mails, we saw on the eastern
head of the harbor the handsome light at Point Koche. u^1 n * Eoclie
Off the mouth of this harbor is an extensive shoal, the
upper end marked by a bell-boat, and the lower by a can- Beii-boat.
buoy, on which the word " Danger " was painted in white
letters.
A few hours after leaving Queenstowa. we passed theH^skar Rock
light-house on Tuskar Eock, at the entrance of St. George's
Channel, evidently an important station. The tower, to
which is attached the double dwelling for the keepers, is
100 feet high. Tuskar Eock is several miles from shore, in
the great highway to Liverpool, so that vessels entering or
leaving St. George's Channel pass quite near it.
It was on this rock that the Cuuard steamship Tripoli
struck a short time ago, and it is evident that the powerful
S. Ex. 54 2
18 EUROPEAN LIGHT-HOUSE SYSTEMS.
fog-signal that the English government proposes to place at
this point is much needed.
Arrival at the On the morning of the 10th we arrived at the mouth of
the Mersey, and, after waiting an hour or more for sufficient
tide to take us over the bar, we proceeded up the river to
Liverpool.
Beii-buoy on On the bar we passed a large bell-buoy, shaped like our
nun-buoys, above the water-line, except that it rested on a
large bearing-surface, projecting a foot or more beyond its
sides.
The sea being quite smooth, the bell was silent, as is too
often the case with this very unreliable kind of signal.
Buoyage of The channel of the river is marked by frequent buoys ;
channel. ou the starboard hand red " can,'7 and on the port black
tl nun."
Light-ships We passed several light-ships, some of which, as Captain
Hgkte. revolving McCauley informed me, have revolving lights, an important
fact to be noted, since a revolving is seen much farther than
a fixed light, and, when light-ships are numerous, as off the
southeastern Irish coast, in the approaches to Liverpool, or
on the shoals off the coast of Massachusetts, distinguishing
characteristics are as necessary as for shore-lights.
Docks, &c., at I spent a day examining the great docks at Liverpool, and
Liverpool. afc Birkenhead, on the opposite side of the river, and became
much interested in the immense walls, the gates and bridges,
swung by hydraulic power, and many other objects which
this is not the place to describe.
TRINITY HOUSE, LONDON.
visit to the Soon after reaching London I called at the Trinity House,
Trinity House. ° .
where I was received with great politeness by Sir Frederick
Arrow, the Deputy Master, who, with Captain Webb, of the
Elder Brethren, visited America during the summer of 1872
for the purpose of attending our fog-signal experiments
made in the harbor of Portland, in the State of Maine, after
which we had the pleasure of meeting them at Washington,
improvements Sir Frederick expressed his gratification at the attentions
in lamps. ^ received in the United States, and after an interesting
conversation regarding our respective establishments, par-
ticularly relating to our fog-signals and to the very great
improvements in light-house lamps made by the Trinity
House, (whereby the quantity of light from the " four- wick »
Advantage lamp for large sea-coast light-houses had been increased 22
per cent., while the consumption of oil had actually been de-
creased more than 19 per cent., an advantage of over 41 per
cent, in favor of the new lamp for large towers, and a still
EUROPEAN LIGHT-HOUSE SYSTEMS. 19
greater one for smaller sea-coast and harbor lights,) he said
that since I informed him of my intended visit to Europe
he had made several engagements for me, including a din-
ner at the Lord Mayor's on the 21st of May, in honor of the
return of the Master of Trinity House, the Duke of Edin-
burgh ; several cruises around the coast of England in the
steam-yachts of the corporation, which were shortly to start
on their annual supply-voyages to the light-stations, and a
visit to Dover, to be present at some fog-signal experiments
to be undertaken by the Elder Brethren under direction of
Professor Tyndall.
It was during this visit that I had the pleasure of meet-
ing Mr. Eobiu Allen, for many years the Secretary of the
Trinity House, and Mr. Edwards, private secretary of the
Deputy Master, who accompanied him on his visit to the
United States.
During my stay in London I made frequent visits to the
Trinity House, and was very soon after my arrival intro-
duced to Mr. Douglass, the talented Engineer of the establish-
ment, and to most of the Elder Brethren ; the pleasure was
also afforded me of meeting my friend Captain Webb, and
I was glad to hear that it was with him that one of my
cruises among the British light-houses was to be made.
Mr. Douglass showed me his plans of some of the more PIMM of light-
important English light-houses, particularly that of the
Wolf Kock, off Land's End, as well as his drawings of
lanterns and lamps. iamrswings °f
It is noticeable that the English, in their lanterns, use Sash-bars in
diagonal sash-bars and low parapets, (or unglazed parts,)
differing in this respect from the French and ourselves.
Mr. Douglass was, as I afterward found the French and interest of EU
other light-house engineers of Europe to be, especially in- in^ia^psTmiS
terested in the subject of lamps as well as that of material for Iigllt"hou8es'
for illumination, these subjects being considered of most
importance at the present time in light-house administra-
tion.
Within the last five or six years improvements have been
made from time to time in lenticular apparatus, but they
are of trifling importance when contrasted with the great increase i
increase of power and concurrent decrease of expense of sea- am
coast lights as compared with the system in use in Europe ex
a few years ago, and with ours of the present time.
These vast ameliorations have been produced by — causes Pro-
1st. The introduction of mineral oil for light-house illumi-
nation.
20 EUROPEAN LIGHT-HOUSE SYSTEMS.
2d. The improvements in u burners " for lamps, resulting
from experiments made to determine the best form of lamps for
burning mineral oil in light-houses, ichich improvements apply
equally to lamps burning oil of a mineral, animal, or vegetable
origin.
This matter will be more fully noted when I come to describe
photometric the depot at Blackwall. I was shown the room devoted to
at8' photometric experiments, where a six- wick lamp burning
colza-oil, a four-wick lamp for mineral oil, and small one-wick
lamps of both the new and old styles were burning for my
inspection.
There was a very remarkable difference of color and bril-
liancy between the flames of the improved and the other
lamps, that of the latter being of a dirty yellowish hue,
while that of the former, being more plentifully supplied
with air, appeared perfectly white, surpassing even the
excellent gas-light of London.
corporation of The Corporation of Trinity House, or, -according to the
original charter, " The Master, Wardens, and Assistants of
the Guild, Fraternity, or Brotherhood of the Most Glorious
and Undivided Trinity, and of St. Clement, in the parish
of Deptford Strond, in the county of Kent," existed as early
tj>ate of char- as the reign of Henry VII, and was incorporated by royal
charter during the reign of Henry VIII.
In the year 1565, in the reign of Queen Elizabeth, the
corporation was empowered, by act of Parliament, "to
preserve ancient sea-marks and to erect beacons, marks,
and signs of the sea," but it was more than a century, i. e.,
Date of first Dot until 1680, before the corporation constructed or owned
owning light-
houses. any light-houses. After that date it from time to time pur-
chased the lights which were owned by individuals or by
Entire control the Crown, and also erected new ones. In 1836 an act of
?estecPh? Trility Parliament vested in the Trinity House the entire control
of the light-houses of England and Wales, and gave it cer-
tain powers over the Irish and Scotch lights.
Light-dues. Prior to* the act of 1836 the charge was from one-sixth of
a penny to one penny per ton on all ships at each time of
passing a light-house, but by this act uniform light-dues of
a halfpenny per ton were established.
At Beii Eock. The charge of one penny per ton at Bell Rock light-house
is the only exception to this uniform rate. By further pro-
is]Jeaeatshipping visions of the act, national ships, fishing- vessels, and ves-
sels in ballast are exempt from light-dues.
Light-houses It should be mentioned that only the light-houses for
not owned by the
Trinity House, general use are owned by the Trinity House, harbor and
other local lights being constructed and maintained at the
EUROPEAN LIGHT-HOUSE SYSTEMS. '
expense of the cities or localities which they especially ben-
efit; but the Trinity House not only has over them a super-
visory control in regard to their sites and plans, but in-
spects them from time to time, thus securing their efficiency.
The Elder Brethren, twenty-nine in number, comprise six- The Eider
teen active members, including two officers of the Navy, Bl
anct thirteen honorary members, all of whom are elected by
the body as vacancies occur.
The honorary members include his royal highness the Honorary mem-
Prince of Wales, some of the ministers to the Crown, sev- bers'
eral members of the nobility and of Parliament.
The Duke of Edinburgh is the present Master, but the Master and
Deputy Master, who is elected by the Elder Brethren from
their active list, is the executive officer.
Out of the annual revenues £350 are paid to each of the salaries.
active members ; these members are organized into commit- Committees,
tees, which meet twice a week except when absent on duty.
The entire board holds weekly sessions, at which the mat- weekly ses-
ters before considered in committee are disposed of.
The corporation of the Trinity House includes also the Junior Breth-
Juuior Brethren, who are elected by the Elder Brethren, and
simply form a reserve from which the Elder Brethren add to
their own number when vacancies occur.
The Junior Brethren have no duties.
Since 1854 the Trinity House has been subordinate to the The Trinity
Board of Trade, whose president is one of the Queen's Min- na°t"sto Board of
isters.
All light-dues collected by the corporation of Trinity The mercantile-
House go into a general fund called " the mercantile-marine m
fund," from which is paid the cost of the maintenance of
the light-house establishment and of the erection of new
lights. This fund is under the control of the Boar<J of Trade,
whose authority must be obtained for the erection of any
new light-house or for any important change in administra-
tion.
This subordination to the Board of Trade extends to the Light -house
light-house boards of Scotland and Ireland, causing, I was ia°nd a8nd Ireland
, -, -, , . . -. , subordinate to
told, much inconvenience and embarrassment. Board of Trade.
Modifications in the light-house administration of Great observations
upon the charac-
Britam have been from time to time suggested and changes ter of the British
may be desirable ; but, judging by my own observations, the
English lights, many more of which I saw than of the Irish and
Scotch, are certainly managed in a most efficient manner,
and, since the great improvements introduced by the emi-
nent engineer, Mr. Douglass, the English may fairly be said
22 EUROPEAN LIGHT-HOUSE SYSTEMS.
to hate placed themselves on an equality with the French,
who have so long led the world in the matter of light-house
illumination.
Trinity House. Trinity House is an ancient structure on Tower Hill,
opposite the old Tower of London, in " The City." It has a
handsome freestone front in classic style. The main en-
trance is on the ground-floor through a capacious hall, where
are exhibited models of many of the most celebrated light-
houses of England, and also of beacons and buoys.
office accomda- Ample accommodations are afforded for the officers, for
the Board and committees, for the Engineer's Department,
and for the photometric experiments, and, in addition,
there is a grand banqueting hall and salon.
I am under obligations to General Schenck, the American
minister ; to Mr. Moran, the secretary; and to Captain Earn-
say, United States Navy, attache of the legation, for offers
of assistance, of which my previous acquaintance with Sir
Frederick Arrow and Captain Webb and the kindness of
the Elder Brethren made it unnecessary for me to avail
myself.
FOGr-SIGrNAL EXPERIMENTS NEAR DOVER.
Experiments On the 19th of May I proceeded to Dover, to be present
og-signas. aj. ^e commencement of an extensive series of fog-signal
experiments, to be undertaken by the Trinity House, under
the supervision of their scientific adviser, Professor Tyndall.
There were present on this occasion, besides Professor
Tyiidall, several of the Elder Brethren, the Engineer of the
Trinity House, a representative from the Board of Trade,
and the Inspector of Irish lights.
The experimenters divided themselves into two parties,
and embarked on two steam -yachts, for the purpose of prac-
tically testing the sounds while afloat.
The limited time at my disposal did not allow me the
pleasure of accepting an invitation to join them, and I had
only an opportunity of observing the machines themselves
at the experimental station at South Foreland. This I did
before inspecting the South Foreland light-houses, to which
I at once proceeded.
Disposition of There were two sets of signals used ; one placed on the
summit of the cliff near the engine-house belonging to the
light-station, at an elevation of 275 feet above the sea; the
other near the foot of the cliff, at an elevation of 40 feet,
and near the bottom of an old shaft, by which it was reached
from the upper station.
EUROPEAN LIGHT-HOUSE SYSTEMS. 23
The machines used were steam-whistles, air-whistles, and
fog-trumpets. The trumpets and the air-whistles were con- ^fanner of 01>
nected with two air chambers, supplied with air by pumps
driven by the engine used for the electric lights.
An Ericsson engine was at the station, but was not used.
The steam-whistles were supplied by a twenty horse-power
upright engine.
The trumpets were shaped like those used in our owu serv- shape and dt-
_ _ . , , , mensions of sig-
ice. The steam- whistles, with a diameter of 12 inches, hadnais.
a height of 14 inches, the space between the lip and the
disk being 1J inches. The air-whistles, with a diameter of
6 inches, were 9J inches high, the lips being placed 1J
inches from the disks.
The steam- whistles were blown under a pressure of 64 pressure used,
pounds; the air-trumpets and whistles under a pressure of
18 pounds. Behind these latter were reflectors about 12 by sound-reflect-
15 feet, slightly curved toward the laud.
The day was stormy, there being a high wind from the
eastward accompanied by rain, and the Strait of Dover was
pretty rough, but on the whole the weather was favorable
for the purpose. The two parties continued afloat all day,
and the signals were sounded until dark.
On shore, so near the signals, and while inspecting the
light-houses, I could not determine in regard to the qualities
of the different sounds as well as could those on board the
yachts, but, so far as I could judge, the air- whistles and
trumpets were decidedly superior to the steam (12-inch)
whistles. The note of the latter was much more shrill than
that found by us to best serve the purpose for which this in-
strument is designed, and the condensation of the steam,
and consequent drip of water* were so great, I was con-
vinced, as to greatly impair the vibration.
The results of the trial of the 12-inch steam-whistle were Results less
. . n . , . satisfactory than
from some cause much less satisfactory than in our expen- at Portland, Me.
ments at Portland, and at our light-stations, the sound pro-
duced being certainly no louder than that of the 6-inch air-
whistle.
On the return of the experimental parties in the evening, op in ions of
. . . experimenters.
there was a general expression of disappointment in regard
to all the signals.
It was stated that the yachts ran outside the limits of Short distance
««,*., at which the
sound at comparatively short distances ; that the air truin- sound failed to
pets and whistles were heard much farther than the steam- re
whistles, while a gun fired at Dover Castle was heard at
much greater distance than any of the signals at the station.
* It may have been water thrown out with the steam in consequence
of the insufficient height of the whistle above the boiler.
24 EUROPEAN LIGHT-HOUSE SYSTEMS.
The yachts were out in the channel occupying various
positions in relation to the wind, and the signals were regu-
larly sounded according to a program me previously arranged.
The experiments, in which were afterward included one
of our own whistles and sirens, were to be continued for
some months. Following will be found a list of the printed
decided.1011 6questions to be considered and answered by the experi-
menters.
" SOUTH FORELAND FOG-SIGNAL EXPERIMENTS.— QUES-
TIONS PROPOSED TO BE DETERMINED.
u First. What is the most efficient height above the sea-
surface for the signals ?
" Second. What are the comparative values of air and
steam for sounding whistles and horns ?
" Third. Which is the more efficient instrument — whistle
or horn ?
u Fourth. What is the proper pressure, having regard to
efficiency and economy, at which air or steam should be em-
ployed for whistles or horns ?
" Fifth. What is the relative range of the same whistle or
horn with various pressures of steam or air ?
" Sixth. What is the relative range of long and short
blasts from the same instrument, and what is the minimum
duration of the blasts of maximum efficiency f
" Seventh. What is the most efficient note for a fog-signal?
" Eighth. What is the relative range of the highest and
lowest notes of the same instrument f
" Ninth. What is the relative range of one and two whis-
tles or horns of the same power ?
" Tenth. What is the relative range of the horn in the di-
rection of its axis, and at 45° and 90° respectively from the
direction of its axis ?
" Eleventh. Is the horn used with maximum efficiency by
always keeping it pointed to windward, by using more than
one horn and distributing the sound over the phonic arcs
or by rotating one horn ?
" Twelfth. Is any appreciable advantage gained by using
reflectors in conjunction with whistles or horns ; and, if so,
what shape is preferable ?
u Thirteenth. What horse-power is required to sound the
most efficient signal (whistle or trumpet) for giving an effect-
ive range (of two miles) in fog and against wind at force 9
of the Beaufort scale ?
" Fourteenth. How is the propagation and distribution of
sound affected by different atmospheric conditions cl "
EUROPEAN LIGHT-HOUSE SYSTEMS. 25
It has been found by General Duane, of the Corps of En- Experiments of
,. General Duaue.
gineers United States Army, and light-house engineer of
the New England coast, in his experiments made to de-
termine the best form of boilers for steam fog-signals, that,
as the steam used is at a high pressure, and is drawn off at
intervals, and there is a consequent tendency to foam and
to throw out water with the steam, a horizontal tubular boiler Boilers best to
i -i n i> it • i • be used for foe-
( locomotive) with rather more than one-half of the interior signals.
space allowed for steam-room, is best adapted for the purpose.
The steam-dome must be very large and be surmounted steam-dome ami
by a steam-pipe 12 inches in diameter. Both dome and pipe
were first made small, and were gradually enlarged until no
difficulty with regard to foaming remained.
The steam should be drawn off at a point 10 feet above DrawinS-off
» ,1-1 point for the
the water-level in the boiler. steam.
The main points, therefore, to be observed in regard to
the boiler j are to have plenty of steam-room and to draw
the steam from a point high above the water-level.
In regard to the bell of the whistle, the best results have rormofwnistie.
been obtained by making the diameter two-thirds of its
length, and the " set" of the bell, i. e., the vertical distance
of the lower edge above the cup, from one-fourth to one-
third of the diameter for a pressure of steam of from 50 to
60 pounds.
These conditions were not fulfilled in the Dover experi-
ments at the time of my visit, and I have no doubt that this
accounts in some measure for the disappointing results of
the trials with the steam-whistle.
Just as this report is going to press I have received from Report of Pro-
Sir Frederick Arrow, Professor Tyndall's report of the fog- f<
signal experiments at South Foreland, which the former has
been kind enough to send me at the moment of its publica-
tion in order that I might make use of it here, and 1 take
pleasure in interpolating at this place some extracts of much
interest.
EXTRACTS FROM PROFESSOR TYNDALL'S REPORT ON FOG-
SIGNALS.
# # # * * * #
" May 20, 1873.— * * * There was nothing, as far Guns not ai-
T . ways superior to
as I am aware of, in our knowledge of the transmission of horns as signals.
sound through the atmosphere, to invalidate the founding
upon these experiments of the general conclusion that, as a
fog-signal, the gun possessed a clear mastery over the horns.
No observation, to my knowledge, had ever been made to
show that a sound once predominant would not be always
predominant, or that the atmosphere on different days
26 EUROPEAN LIGHT-HOUSE SYSTEMS.
would show preferences to different sounds. A complete
reversal of the foregoing conclusion was, therefore, not to
be anticipated ; still, on many subsequent occasions, it was
completely reversed.
* * * * * * *
signals on top " The observations of May 19 and 20 proved that no ad-
to tho^eSateboS vantage was gained by placing the horns at the bottom
tom- of the cliff. With scarcely an exception the higher horns
proved in all cases slightly superior to the lower ones. In
subsequent experiments, therefore, the higher horns alone
were for the most part invoked.
* ******
"June 3. — At seven miles we halted ; the sound of the
horns was here very distinct, the steam- whistle being also
well heard.
" While in this position an exceedingly heavy rain-shower
approached at a galloping speed. It could hardly have
been borne forward with such velocity by the wind, which
had only a force of 2. Its advance was proba.bly due to the
rapid successive condensation of different parts of the same
continuous cloud. The sounds were not sensibly impaired
during the continuance of the rain. Not till subsequently
was the influence of such a shower in clearing the air un-
derstood. At eight miles the whistles were still heard and
the horns better heard. At nine miles the whistles ceased
to be heard, while the horns continued to be fairly audible.
TT s e of t w o " In no case did any sensible inequality show itself between
the sound of the single horn and that of the pair of horns.
The beats of the two horns were, however, very character-
istic at the longer distances. The blasts of the horns were
not of uniform strength; even in the same blast sudden
swellings out and fallings off of the sounds were observed.
* * * * * * *
Effect of the " June 11.—* * * The fall of the sound is not caused
acoustic shadow. direct]y by tne acOustic shadow, for it occurs when the in-
struments are in view ; but the limit of the acoustic shadow
is close at hand. A little within the line joining the Fore-
land and the pier end the instruments are cut off by a pro-
jection of the cliff near the station. * * * All the sea-
space between this 'boundary' and the cliff under Dover Cas-
tle is in the shadow. Into this, however, the direct waves
diverge, and lose intensity by their divergence, the portion
of the wave nearest the shadow suffering most. Hence, I
doubt not, one cause of the decay of the sound in the posi-
tion here referred to. The interference of sound reflected
from the cliff with the direct sound doubtless also coutrib-
EUROPEAN LIGHT-HOUSE SYSTEMS. 27
utes to the effect. Iii establishing a fog-signal station such
matters must be carefully attended to.
#######
" July 1. — * * * Here a word of reflection on our Accepted theo-
u ry 01 loss 01 sound
observations may be fitly introduced. It is an opinion en- ^ fog.
tertaiued in high quarters that the waves of sound are re-
flected at the limiting surfaces of the minute particles which
constitute haze and fog, the alleged waste of sound in fog
being thus explained. Dr. Bobinson, for example, defines Dr.
fog to be 'a mixture of air and globules of water,7 and states "e
' that at each of the innumerable surfaces where these two
touch a portion of the vibration is reflected and lost.' Theo-
retically it may be so ; but if this were an efficient practical
cause of the stoppage of sound, it would be difficult to un-
derstand how to-day, in a thick haze, the sound reached a
distance of twelve and three-quarters miles ; and that on
May 20, in a calm and hazeless atmosphere, the maximum
reach of the sounds was only from five to six miles. Such
facts foreshadow a revolution in our notions regarding the
action of haze and fogs upon sound.
*******
" July 2. — In the foregoing observations we have had very Fluctuations in
remarkable fluctuations in the range of the sound, that range rangeo
vary ing from three or four miles on May 19 to ten and one-half
or twelve and three-quarters on the 1st of July. The direc-
tion and force of the wind, known to exercise a potent in-
fluence upon sound, entirely fail to account for these fluc-
tuations, nor could any other observed meteorological ele-
ment be held responsible for them. Prior to July 3 sur-
mises more or less vague had passed through my mind re-
garding them ; but all remained uncertain until on the 3d
surmise and perplexity were, to a great extent, displaced
by clear physical demonstration.
"On July 3 we first steamed to a point 2.9 miles southwest Acoustic opac-
by west of the signal-station. No sounds, not even the ity °f air July 3'
guns, were heard at this distance. At two miles they were
equally inaudible. But this being the position in which
the sounds, though strong in the axis, invariably subsided,
we steamed to the exact bearing from which our observa-
tions had been made upon July 1. At 2.15 p. m., and at a
distance of three and three-quarters miles from the station,
with calm air and a smooth sea, the horns and whistle
(American) were sounded, but they were inaudible. Sur-
prised at this result, I signaled for the guns. They were
all fired, but, though the smoke seemed at hand, no sound
whatever reached us. On July 1, in this bearing, the range
28 EUROPEAN LIGHT-HOUSE SYSTEMS.
of both horns and guns was ten and a half miles. We
steamed in to three miles, paused, and listened with all
attention, but neither horn nor whistle was heard. The
guns were again signaled for $ five of them were fired in
succession, but not one of them was heard. We steamed
in on the same bearing to two miles, and had the guns
fired point-blank at us. The howitzer and the mortar, with
3-pound charges, yielded a feeble thud, while the IS-pounder
was wholly unheard. Applying the law of inverse squares,
it follows that, with air and sea in an apparently worse
condition, the sound at two miles distance on July 1 must
have had at least five-and twenty times the intensity which
it possessed at the same distance on, the 3d.
" With the Foreland so close to us, the sea so calm, and the
air so transparent, it was difficult, indeed, to realize that
the guns had been fired or the trumpets sounded at all.
What could have caused this extraordinary stifling of the
sound? Had it been converted by internal friction into
heat? Or had it been wasted in partial reflections at the
limiting surfaces of non-homogeneous masses of air? A
few words will render this question intelligible to the gen-
eral reader. Sulphur in homogeneous crystals is exceed-
ingly transparent to radiant heat, whereas the ordinary
brimstone of commerce is highly impervious to it. Why?
Because the brimstone of commerce does not possess the
molecular continuity of the crystal, but is a mere aggregate
of minute grains not in perfect optical contact with each
other. Where this is the case, a portion of the heat is
always reflected on entering and on quitting a grain.
Hence when the grains are minute and numerous this re-
flection is so often repeated that the heat is entirely wasted
before it can plunge to any depth into the substance. A
snow-ball is opaque to light for the same reason. It is not
optically continuous ice, but an aggregate of grains of ice,
and the light which falls upon the snow being reflected at
the limiting surfaces of the snow-granules, fails to pene-
trate the snow to any depth. Thus, by the mixture of air
and ice, two transparent substances, we produce a sub-
stance as impervious to light as a really opaque one. The
same remark applies to foam, to clouds, to common salt,
indeed to all transparent substances in powder. They are
all impervious to light, not through the real absorption or
extinction of the light, but through internal reflection.
" Humboldt, in his observations at the Falls of the Orinoco,
? is kll°wn to have applied these principles. He found the
noise of the falls three times louder by night than by day,
EUROPEAN LIGHT-HOUSE SYSTEMS. 29
though in that region the night is far noisier than the day.
The plain between him and the falls consisted of spaces of
grass and rock intermingled. In the heat of the day he
found the temperature of the rock to be 30° higher than
that of the grass. Over every heated rock, he concludedf
rose a column of air rarefied by the heat, and he ascribed the
deadening of the sound to the reflections which it endured
at the limiting surfaces of the rarer and the denser air. This
philosophical explanation made it generally known that a
•non-homogeneous atmosphere is unfavorable to the trans-
mission of sound.
" But what, on July 3, with a calm sea as a basis for the Reasons for the
, , non- homogeneity
atmosphere, could so destroy its homogeneity as to enable of the a tmo fl-
it to quench in so short a distance so vast a body of sound? p
As I stood upon the deck of the Irene pondering this ques-
tion I became conscious of the exceeding power of the sun
beating against my back and heating the objects near me.
Beams of equal power were falling on the sea, and must
have produced copious evaporation. That the vapor gen-
erated should so rise and mingle with the air as to form an
absolutely homogeneous mixture I considered in the highest
degree improbable. It would be sure, I thought, to streak
and mottle the atmosphere with spaces in which the air
would be in different degrees saturated, or it might be dis-
placed by the vapor. At the limiting surfaces of these
spaces, though invisible, we should have the conditions ne-
cessary to the production of partial echoes, and the conse-
quent waste of the sound.
" Curiously enough, the conditions necessary for the test- clouds causing
ing of this explanation immediately set in. At 3.15 p. in. ajjjj.
cloud threw itself athwart the sun and shaded the entirerea(lily-
space between us and the South Foreland. The production
of vapor was checked by the interposition of this screen,
that already in the air being at the same time allowed to
mix with it more perfectly $ hence the probability of im-
proved transmission. To test this inference I had the
steamer turned and urged back to our last position of in-
audibility. The sounds, as I expected, were distinctly
though faintly heard. This was at three miles' distance. At
three and three-quarters miles we had the guns fired, both
point-blank and elevated. The faintest pop was all that we
heard ; but we did hear a pop, whereas we had previously
hoard nothing, either here or three-quarters of a mile nearer.
We steamed out to four and a quarter miles, where the sounds
were for a moment faintly heard ; but they fell away as we
waited, and though the greatest quietness reigned on board,
30 EUROPEAN LIGHT-HOUSE SYSTEMS.
and though the sea was without a ripple, we could hear
nothing. We could plainly see the steam-puffs which an-
nounced the beginning and end of a series of trumpet-blasts,
but the blasts themselves were quite inaudible.
"It was now 4 p. m., and my intention at first was to halt
at this distance, which was beyond the sound-range, but
not far beyond it, and see whether the lowering of the sun
would not restore the power of the atmosphere to transmit
the sound. But, after waiting a little, the anchoring of a
boat was suggested, so as to liberate the steamer for other
work ; and though loath to lose the anticipated revival of the
sound myself, I agreed to this arrangement. Two men were
placed in the boat and requested to give all attention so as
to hear the sound if possible. With perfect stillness around
them they heard nothing. They were then instructed to
hoist a signal if they should hear the sounds, and to keep it
hoisted as long as the sound continued.
" At 4.45 we quitted them and steamed toward the South
Sand Head light-ship. Precisely 15 minutes aftefe we had
separated from them the flag was hoisted. The sound had
at length succeeded in piercing the body of air between the
boat and the shore.
" We continued our journey to the light-ship, went on
board, and heard the report of the light sm en. Eeturning
toward the Foreland, in answer to a signal expressing a
wish to communicate with us, we manned a boat and pulled
to the shore. The exhaustion of the ammunition was re-
ported, but the horns and whistle continued to sound. We
steamed out to our anchored boat, and then learned that
when the flag was hoisted the horn -sounds were heard ;
that they were succeeded after a little time by the whistle-
sounds, and that both increased in intensity as the evening
advanced. On our arrival, of course we heard the sounds
ourselves.
"The explanation given above of the stoppage of the sound
is in perfect harmony with these observations. But we
pushed the test further by steaming farther out. At five
and three-quarters miles we halted and heard the sounds.
At six miles we heard them distinctly, but so feebly that
we thought we had reached the limit of the sound-range.
But while we waited the sound rose in power. We steamed
to the Varne buoy, which is seven and three-quarters miles
from the signal- station, and heard the sounds there better
than at six miles distance. We continued our course out-
ward to ten miles, halted there, but heard nothing.
EUROPEAN LIGHT-HOUSE SYSTEMS. 31
"At eight miles' distance the sound in the evening was at signals heard
rr\i i a* eight miles in
least as well heard as at two miles in the morning. That the evening.
this could occur it was necessary, in accordance with the
law of inverse squares, that the sound at two miles' distance
should have risen in the evening to an intensity at least six-
teen times that which it possessed in the morning.
" Steaming on to the Varne light-ship, which is situated at
the other end of the Yarne Shoal, we hailed the master, and
were informed by him that up to 5 p. m., nothing had been
heard. At that hour the sounds began to be audible. He
described one of them as i very gross, resembling the bel-
lowing of a bull,' which very accurately characterizes the
sound of the large American steam -whistle. At the Varne
light-ship, therefore, the sounds had been heard toward the
close of the day, though it is twelve and three-quarters miles
from the signal-station. On our return to Dover Bay at 10
p. m. we heard the sounds, not only distinct but loud,
where nothing could be heard in the morning.
"I have already referred to the winds and currents which winds and cur-
establish themselves round the South Foreland. Mr. Holmes Foreland.
was, as usual, there on July 3, and he informed me that,
from the motion of the smoke of some passing steamers and
from the sails of sailing- vessels, he could recognize a curious
circulation of the air from laud to sea. The wind would
sometimes hug the cliff to the northeast of the Foreland ;
then bend around and move toward the South Sand Head
light-ship. And, in point of fact, the wind at the light-
vessel had been southwest, with a force of 3 nearly the
whole of the day; whereas with us it had passed from south-
west by west to a dead calm, and afterward to southeast. On
shore also it had shifted from southwest to southeast. The
atmospheric conditions between the light-vessels and the
Foreland were, therefore, different from those between us
and the Foreland; and the consequence was that at the time
when we were becalmed and heard nothing the light-keepers,
with the larger component of a wind of 3 acting against the
sounds, heard them plainly all day.
" But both the argument and the phenomena have a com- Reflection of
plementary side, which we have now to consider. A stratum
of air three miles thick on a perfectly calm day has been
proved competent to stifle both the cannonade and the horn
sounds employed at the South Foreland ; while the observa-
tions just recorded seem to point distinctly to the mixture
of air and aqueous vapor as the cause of this extraordinary
phenomenon. Such a mixture could fill the atmosphere with
32 EUROPEAN LIGHT-HOUSE SYSTEMS.
an impervious acoustic cloud on a day of perfect optical trans-
parency. But, granting this, it is incredible that so great
a body of sound could utterly disappear in so short a distance
without rendering any account of itself. Supposing, then,
instead of placing ourselves behind the acoustic cloud, we
were to place ourselves in front of it, might we not, in
accordance with the law of conservation, expect to receive
by reflection the sound that had foiled to reach us by trans-
mission? The case would then be strictly analogous to
the reflection of light from an ordinary cloud to an observer
placed between it and the sun.
Echoes ob- « My first care in the early part of the day in question was
to assure myself that our inability to hear the sound did
not arise from any derangement of the instruments on shore.
Accompanied by Mr. Edwards, who was good enough on
this and some other days to act as my amanuensis, at 1 p.
m. I was rowed to the shore, and landed at the base of the
South Foreland cliff. The body of .sir which had already
shown such extraordinary power to intercept the sound,
and which manifested this power still more impressively
later in the day, was now in front of us. On it the sono-
rous waves impinged, and from it they were sent back to
us with astonishing intensity. The instruments, hidden
from view, were on the summit of a cliff 235 feet above us,
the sea was smooth and clear of ships, the atmosphere was
without a cloud, and there was no object in sight which
could possibly produce the observed effect. From the per-
fectly transparent air the echoes came, at first with a strength
apparently but little less than that of the direct sound, and
then dying gradually and continuously away. A remark
made by my talented companion in his note-book at the time
shows how the phenomenon affected him. 'Beyond saying
that the echoes seemed to come from the expanse of ocean,
it did not appear possible to indicate any more definite point
of reflection.' Indeed, no such point was to be seen ; the
echoes reached us, as if by magic, from absolutely invisible
walls.
u Here, I doubt not, we have the key to many of the mys-
teries and discrepancies of evidence which beset this ques-
tion. The foregoing observations show that there is no
need to doubt either the veracity or capability of the con-
flicting witnesses, for the variations of the atmosphere are
more than sufficient to account for theirs. The mistake, in-
deed, hitherto has been, not in reporting incorrectly, but in
neglecting the monotonous operation of repeating the ob-
servations during a sufficient time. I shall have occasion
EUROPEAN LIGHT-HOUSE SYSTEMS. 33
to remark subsequently on the mischief likely to arise from
givine: instructions to mariners founded on observations of
this incomplete character.
" The more accurate comprehension of various historic striking cases
1 of non-transrais-
occurrences will be rendered possible by these observations, sum of sound.
In his lecture entitled l Wirkungen aus der Feme,' the emi-
nent Berlin philosopher, Dove, has collected some striking
cases of this kind. During the battle of Cassano, on the
Adda, between the Due tie Vendome and the Prince Eugene,
an army -corps stationed under the duke's brother, five
miles up the river, failed to join the battle through not
hearing the cannonade. In a river-valley, particularly on
a warm day, it would, in my opinion, be very perilous to
place much dependence upon sound. Near Montereau, on
the Seine, during the battle between Napoleon I and the
King of Wiirtemberg, which lasted seven hours, no sound
of the conflict was heard by Prince Schwartzenberg, thirteen
miles up the river. A Prussian officer sent thither at noon
first heard the cannonade at a distance of four and a half
miles from the field of battle. This happened on a day
apparently resembling in point of mildness and serenity our
3d of July. In the battle of Liegnitz, where Frederick the
Great overthrew Laudon, the sound of the battle was un-
heard by Field-Marshal Daun, who was posted on a height
four and a half miles from the battle-field. Dove himself
recounts the fact of his having failed to catch a single shot
of the battle of Katzbach, at four and a half miles distance,
while he plainly heard the cannonade of Bautzen, eighty
miles away.
" The stoppage of the sound in the foregoing cases Dove other instances
referred, and doubtless correctly, to the non-homogeneous Jfe
character of the air. He also notes the exceedingly inter- phere"
estiug observation that in certain clear winter days, when
the sun has already attained some power, the semaphore is
difficult to decipher, the reason being that by the solar
warmth upward currents of warm and downward currents
of cold air (similar to those of Humboldt on the plain of
Autures) are established, and that such days are also un-
favorable to the transmission of sound. In another pas-
sage, however, he seems to endorse the prevalent notion
that the transparency of the air and its power to transmit
sound go hand in hand ; whereas in our experiments days
of the highest optical transparency proved themselves
acoustically most opaque.
" < Over water,' says Sir John Herschel, « or a surface of
ice, sound is propagated with remarkable clearness and
S. Ex. 54 3
34 EUROPEAN LIGHT-HOUSE SYSTEMS.
strength ; ' and he refers to the well-known case of Lieu-
tenant Foster, who, in the polar expedition of Captain
Parry, carried on a conversation across the frozen harbor of
Port Bowen, which is a mile and a quarter wide. But as
regards smoothness, water could hardly be in a better con-
dition than the sea between the Irene and the South Fore-
land on the 3d of July. Still, though aided by reflection
from the sea's surface, the sound was powerless to penetrate
the air. And in regard to Lieutenant Foster's observation,
there cannot, I think, be a doubt that the extraordinary
acoustic transparency of the polar atmosphere is mainly due
to the absence of that flocculence which in our observations
proved so hostile to the transmission of the sound. To the
same cause is, I believe, to be ascribed the hearing of can-
nonades at the extraordinary distances of eighty, one hun-
dred and eighty, and two hundred miles, mentioned by Sir
John Herschel in his essay on sound. Had Humboklt him-
self been aware of the observations here recorded, might not
his classical observation also have been connected with the
vapor raised from the Orinoco by a tropical sun I
Experiments " In the celebrated experiments conducted by the cominis-
v!l£^Tam£i sion of the French Bureau des Longitudes in 1822, two sta-
des Longitudes. tioDS were chosen, 11.6 miles apart, the one at Montlhery,
and the other at Villejuif, near Paris. Two remarkable
phenomena, which have a special interest in relation to our
observations, presented themselves to the observers ; the
one was that while the report of every gun fired at Mont-
lhery was exceedingly well heard at Villejuif, by far the
greater number of those fired at Yillejuif failed to be heard at
Montlhery. In reference to this point Arago, the writer of
the report, with that philosophic reserve which he showed
in other matters, expressed himself thus : 'Quant aux diffe"-
rences si remarquables d'intensite que le bruit du canon a
toujours presentees suivant qu'il se propageait du nord au
sud entre Villejuif et Montlhery, ou du sud au nord entre
cette seconde station et la premiere, nous ne chercherons
pas aujourd'hui a les expliquer, parceque nous ne pourrions
offrir au lecteur que des conjectures denuees des preuves.'
To another phenomenon he also directs attention, offering
not only a description, but an explanation : ' Avant de ter-
miner cette note, nousajouterons seulement que tous les
coups tires a Montlhery y etaient accompagnes d'un roule-
ment semblable a celui da tonnerre, et qui durait 20" a 25".
Biende pareil n'avait lieua Villejuif $ il nous est arrive" seule-
raent d'eutendre, a moins d'une seconde d'intervalle, deux
coups distincts du canon de Moutlhery. Dans deux autres
EUROPEAN LIGHT-HOUSE SYSTEMS. 35
circonstanees le bruit de ce canon a ete accoinpagne" d'un
roulemeut prolonge. Ces pheuoinenes n'ont jamais eu lieu
qu'au moment d7 apparition de quelques uuages ; par un ciel
completement serein le bruit etait unique et instantane.
Ke serait-il pas permis de conclure de la qu'a Villejuif les
coups multiples du canon de Montlhery resultaient d'echos
formes dans les nuages, et de tirer de ce fait un argument
favorable a Fexplication qu'ont donne"e quelque physi-
•cieus du roulement du tonnerreT
" It is not here stated, that at Montlhery the clouds were
seen when the echoes were heard. The explanation of the
Montlhery echoes is in fact an inference from observations
made at Villejuif. I think that inference requires qualifica-
tion . Some hundreds of cannon-shots have been fired at the
South Foreland, many of them when the heavens were com-
pletely free from clouds, and never in a single case has
a 'rotilement* similar to that noticed at Montlhery been ab-
sent. It follows, moreover, so hot upon the direct sound as
to present scarcely a sensible breach of continuity between
the sound and the echo. This could not be the case if the
clouds were its origin. A reflecting cloud, even at the short
distance of 1,000 yards, would leave a silent interval of five
seconds between the sound and the echo. Had such an inter-
val been observed at Montlhery it could hardly have escaped
record by the philosophers stationed there.
" But, to fall back from reasoning upon facts, it is certain Echoes produced
that air of perfect visual transparency is competent to pro- air.tra
duce echoes of great intensity and long duration. I shall
have further occasion to refer to such echoes $ for it was not
with whistles, nor trumpets, nor guns, that these echoes in
our observations reached their greatest development, but
with the steam-siren, to be described farther on. The blasts
sounded by this instrument number, I believe, about twenty
thousand 5 but whatever might be the state of the weather,
cloudy or serene, stormy or calm, no single blast of the siren
failed to be accompanied by echoes of astonishing strength.
" The other point referred to, which Arago declined to dis-
cuss, presents a grave difficulty. No attempt, as far as I
am aware of, has since been made to solve it,*or even to show
that a solution is conceivable. I think the foregoing obser-
vations might be shown to have some bearing upon the point.
Arago makes incidently the significant remark that, on June
22, when only one out of twelve of the shots fired at Ville-
juif was heard, and that feebly, at Montlhery, ' Thygrometre
avait marche beaucoup a 1'humidite;' and farther on he
speaks of the air as i tout pres du terme de 1'humidite ex-
36 EUROPEAN LIGHT-HOUSE SYSTEMS.
treine.' I believe myself safe in saying that air thus moving
rapidly toward its point of saturation is sure to yield echoes;
and the fact that echoes were heard at Montlhery and not at
Villejuif is a proof of the different hygrometric condition of
the air at the two stations. With the light wind recorded
in the report, Montlhery would probably be swathed by
vapor from the valley of the Seine. It seems to me by no
means impossible to imagine a distribution of vapor sufficient
to produce the observed effect; but this is a subject which
may be reserved for future investigation.
" The observations of July 3, 1 believe, reveal to us the
most potent cause of the caprices of the atmosphere as re-
gards the transmission of sound. We shall, moreover, find
them throwing light upon anomalies subsequently observed,
which, without their aid, would be perplexing in the high-
est degree.
* * * * # * * •
American siren " During my recent visit to the United States I was
S?nt.f°r esperi" favored by an introduction to General Woodruff by Professor
Joseph Henry, of Washington. Professor Henry is chair-
man of the Light-House Board, and General Woodruff is
engineer in charge of two of the light-house districts. I
accompanied General Woodruff' to the establishment at
Staten Island, and afterward to Sandy Hook, with the
express intention of observing the performance of the
steam-siren which, under the auspices of Professor Henry,
has been introduced into the light-house system of the
United States. Such experiments as were possible to make
under the circumstances were made, and I carried home
with me a somewhat vivid remembrance of the mechanical
effect of the sound of the steam-siren upon my ears and
body generally. This I considered to be greater than the
similar effect produced by the horns of Mr. Holmes ; hence
the desire, on my part, to see the siren tried at the South
Foreland. The formal expression of this desire was antici-
pated by the Elder Brethren, while their wishes were in
turn anticipated by the courteous kindness of the Light-
House Board at Washington. Informed by Major Elliot
that our experiments had begun, the Board forwarded to
the corporation, for trial, the noble instrument now mounted
at the South Foreland.
Principle of the "The principle of the siren is easily understood. A mu-
sical sound is produced when the tympanic membrane is
struck periodically with sufficient rapidity. The production
of these tympanic shocks by puffs of air was first realized by
Doctor Eobisou, and his device was the first and simplest
EUROPEAN LIGHT-HOUSE SYSTEMS. 37
form of the siren. A stop-cock was so constructed that it
opened and shut the passage of a pipe seven hundred and
twenty times in a second. Air being allowed to pass inter-
mittently along the pipe by the rotation of the cock, 4a mu-
sical sound was most smoothly uttered.' A great step was
made in the construction of this instrument by Cagniard de
la Tour, who gave it its present name. He employed a box
with a perforated lid, and above the lid a similarly perfo-
rated disk, capable of rotation. The perforations were
oblique, so that when wind was driven through, it so im-
pinged upon the apertures of the disk as to set it in motion.
No separate mechanism was therefore required to move the
upper disk. When the perforations of the two disks coin-
cided, a puff escaped ; when they did not coincide, the cur-
rent of air was cut off. In this way a succession of im-
pulses was imparted to the air. The siren has been
greatly improved by Dove, and specially so by Helmholtz.
Even in its small form the instrument is capable of produc-
ing sounds of great intensity.
uln the steam-siren, patented by Mr. Brown, of New York,
a fixed disk and a rotating disk are also employed, radial
slits being cut in both disks instead of circular apertures.
One disk is fixed across the throat of a trumpet, 1CJ feet
long, 5 inches in diameter, where the disk crosses it, and
gradually opening out till at the other extremity it reaches
a diameter of 2 feet 3 inches. Behind the fixed disk is the
rotating one, which is driven by separate mechanism. The
trumpet is mounted on a boiler. In our experiments steam
of 70 pounds pressure has for the most part been employed.
Just as in the siren already described, when the radial
slits of the two disks coincide, a puff of steam escapes.
Sound-waves of great intensity are thus sent through the
air ; the pitch of the note produced depending on the
rapidity with which the puffs succeed each other ; in other
words, upon the velocity of rotation.
*******
" October 8. — * * * The heavy rain at length reached sound not dead-
us, but although it was falling all the way between us and ra.
the Foreland, the sound, instead of being deadened, rose
perceptibly in power. Hail was now added to the rain, and
the shower reached a tropical violence. The deck was
thickly covered with hail-stones, which here and there
floated upon the rain-water, the latter not having time to
escape. We stopped. In the midst of this furious squall
both the horn and the siren were distinctly heard j and as
the shower lightened, thus lessening the local noises, the
38 EUROPEAN LIGHT-HOUSE SYSTEMS.
sounds so rose in power that we heard them at a distance
of seven and a half miles distinctly louder than they had
been heard through the rainless atmosphere at five miles.
This observation is entirely opposed to the statement of
Derhain, which has been repeated by all writers since his time,
regarding the stifling influence of falling rain upon sound.
But it harmonizes perfectly with our experience on the 3d
July, which proved water in the state of vapor , so mixed with
air as to form non-homogeneous parcels, to be a most potent
influence as regards the stoppage of sound. Prior to the
violent showers of to-day the air had been in this condition,
but the descent of the shower restored in part the homoge-
neity of the atmosphere and auguinented its transmissive
power.
" In the cleansed and cool atmosphere the horn-sound ap-
peared to improve more than that of the siren, slightly
surpassing it at times. The horn-note was of lower pitch ;
hence it might be inferred that the change in the atmos-
phere favored specially the transmission of the longer waves.
" Up to this time the siren had been performing 2,400
revolutions a minute ; the rate was now reduced to 2,000 a
minute. The sound immediately surpassed that of the horn.
By this experiment the foregoing inference was reduced to
demonstration; a highly instructive result, as it showed an
interdependence between aerial reflection and the lengths
of the sonorous waves.
"At 4 p. m. the rain had ceased, the sun shone clearly
out : the air was calm afloat, but west with a force of 2,
ashore. At nine miles' distance the horn was heard feebly,
the siren clearly ; the howitzer at this distance sent us a
loud report. All, indeed, seemed better at this distance
than at five and one half miles;, from which it follows that
at this latter distance the intensity of the sound must have
been augmented at least threefold by the descent of the
rain.
*******
" October 10.—* * * We descended the 12-ladder shaft,
and from the lower station listened to the gun, the upper
horn, the siren, and the lower horn. The sound of the
siren was strikingly distinguished from that of the upper
horn by its hardness and almost explosive force. Its echoes
also were much louder and longer continued than those of
the horn ; and from this alone its greater reach of penetra-
tion might be inferred. The noise of the surf, however, at
the lower station, interfered seriously with the observa-
tions.
EUROPEAN LIGHT-HOUSE SYSTEMS. 39
" October 13.—* * * On steaming toward the axis no
echo for some time was generated by the horns, none by the
Canadian whistle, but long-drawn and distinct echoes carae
from the south in the case of the siren. When quite
abreast of the station the horn-echoes were also heard, but
they failed to approach in intensity those of the siren.
" Near the shore the wind was now north ; farther out it was yh ?a(JJ'R!?
southwest, and we steamed between the two currents. As cribed to rain.
far as the South Sand Head light-ship all the sounds were
heard both through violent rain and through the noise of the
paddles. To rain I have never yet been able to trace any
deadening power ; indeed such rain as we have hitherto en-
countered produced a distinctly opposite effect, and the
reason is now intelligible. The siren on the present occa-
sion was clearest and loudest, though at times the Cana-
dian whistle showed great power. A struggle between the
winds continued for some time, the north wind, accompanied
by a cool atmosphere, at length prevailing.
"Once while halting near the light-ship, when the Fore- superiority of
...»t-. • ,,tho Americau
land was hidden in a dense ram-mist, I, Lemg ignorant ol siren,
its bearing, immediately found its position from the direc-
tion of the sound.
"Thomson, the chief lamp-lighter at the South Sand Head,
an exceedingly intelligent man, reported that on all occa-
sions the sound of the siren had the mastery; and that
opinion 011 this point was unanimous on board the light-
vessel. On Friday and Saturday the sounds, he reported,
were but faintly heard, being probably impaired by the lo-
cal noises. To-day we found during our visit all the sounds
very good, that of the siren being particularly intense.
* * * * * * *
" October 14.—* * * At 11.30 a. m. a gun was fired at Error in sup-
posing a shrill
the Foreland ; report distinct. Up to this time the Cana- note to be supe-
rior as a signal.
dian whistle had been adjusted to produce a shrill note ; it
was not heard. The piercing shrillness of this note, when
heard at the South Foreland on October 10, suggested its
trial to-day. The opinion that a note of this character,
which affects an observer close at hand so powerfully and
painfully, has also the greatest range, is a common one, and
might be true in connection with homogeneous atmosphere.
But in 'flocculent' air the shorter waves suffer most from par-
tial reflection, exactly as the shorter waves of solar light
suffer most in their passage through the suspended matter
of the atmosphere. The blue of the firmament is, in fact,
the echo of these shorter undulations.
40 EUROPEAN LIGHT-HOUSE SYSTEMS.
"According to arrangement, the Canadian whistle was now
changed to its old low pitch. It was immediately heard at
the Varne buoy.
*******
" During the earlier part of this day the atmosphere, which,
throughout, was of extreme optical clearness, favored the
transmission of the longer sound-waves, corresponding to the
deeper sounds.
changes in the "After a lapse of three hours the case was reversed, the
atmosphere on , ,
the same day. high-pitched siren being heard when both gun and horns
were absolutely inaudible. But even this was not perma-
nent. Such changes on the part of the atmosphere have
never hitherto been noticed, nor am I aware of a single ob-
servation bearing upon this selective stoppage of the sound.
Its optical analogies have been already pointed out. The
parcels of air and vapor play, to some extent, the same part
in scattering the waves of sound as the minute particles sus-
pended in the atmosphere do in scattering the solar light,
producing by their preferences in this respect the blue of
the sky.
*******
Daboii's inven- " October 15.—* * * To the late Mr. Daboll, of the
tion of fog-horns. unite(l States, belongs the credit of bringing large trumpets
into use as fog-signals. At Dungeness one of his horns had
been erected under his own superintendence ; and wishing
to make myself acquainted with its performance, we steamed
Horn at Dun- thither to-day. On examining the horn, I was struck by
its similarity in all essential particulars to the horns em-
ployed at the South Foreland. Considerable improvements
in the working of the horn have been introduced by Mr.
Holmes, but the horn itself is substantially that of Daboll.
*******
" October 18. — * * * There is no doubt that two days
might be chosen on one of which the report of a pocket-pis-
tol would be further heard than the report of an 18-pounder
on the other. * * * *
"October 23. — * * * In the observations of Mr. Ayres
to the west of the Foreland, wind and sound were almost in
direct opposition ; in those of Mr. Douglass they were by
no means coincident. For a time both directions inclosed an
angle of about 45°, and subsequently a greater angle. The
Effect of athun- difference in the results is nevertheless striking. I may here
atmSpheerreOIltbe draw attention to the remarkable effect of the rain and
thunder-storm observed by Mr. Douglass. He was well
in the sound-shadow near Kingsdown coast-guard station.
He had sent a fly in advance of him, and the driver had
EUROPEAN LIGHT-HOUSE SYSTEMS. 41
been waiting for him for fifteen minutes without once hear-
ing either trumpets or gun ; nor had the coast-guardsman
on duty heard any sound throughout the day. In fact, the
the atmosphere prior to the thunder-storm was in that floc-
culent condition to which I have so often had occasion to
refer, being composed of non-homogeneous locks of air and
vapor. The thunder- storm, which I am assured by Mr.
Douglass resembled the descent of a water-spout rather
than of an ordinary shower of rain, abolished this condition
of things, diminishing the partial echoes, and opening a freer
way for the sound through the atmosphere.
'•In the case of. Mr. Ay res, the mastery of the siren ov
the gun was very conspicuous ; in the case of Mr. Douglass siren
also, though the difference was not so great, the siren was
heard a mile farther than the gun.
# * * * * * #
" October 31. — * * * This was an exceedingly thick
and squally day, with dense clouds and vapor everywhere.
In acoustic opacity it was almost a match for the memo-
rable 3d of July.
u Steamed with a view of getting dead to windward of
station. The siren was clearly heard through all noises.
During one particularly heavy squall, when the wind rose
to a force of 8, the siren sent us a forcible sound, the horns
at the same time being quite inaudible.
* * * * * # *
" November 21. — * * * The result of the day's obser- Resuft of di-
vations was to prove that the siren suffered far more in
being directed from us than the gun ; this means that 8e
the conical trumpet associated with the siren is far more
effectual in gathering up the sound and sending it in the
direction of the axis than is the cylinder of the gun.
" The siren, pointed on us, was heard to-day through the
paddle noises at a distance of five miles.
" We made various observations in the sound-shadow and
near it. The fluctuations in the strength of the sound in-
dicated that we were passing through spaces of interference,
the sound being sometimes suddenly augmented and some-
times suddenly deadened.
*******
" In the neighborhood of an acoustic shadow — we need
not be in the shadow— and with a wind of a force of 4 tic
against the sound, there are states of the atmosphere in
which even the siren with its axis pointed on the observer
could not be trusted for a distance of one and a half miles.
42 EUROPEAN LIGHT-HOUSE SYSTEMS.
Horns, whistles, and guns, under those circumstances, are
simply nowhere.
* * * * . * * *
General re- «^_ brief review of our proceedings will aid the memory of
the reader who has taken the trouble of going over the fore-
going pages. Daboll's horn had been highly spoken of by
writers on fog-signals. A third-order apparatus of the kind
has been reported as sending its sound to a distance of from
seven to nine miles against the wind, and to a distance of
twelve to fourteen miles with, the wind. Holmes had im-
proved upon Daboll, and with an instrument of Holmes of
mentmmence ^ne ^rs^ or(^er our experiments were made. They began on
the 19th of May, 1873. Whistles were also employed on this
occasion, but those tested were speedily put out of court.
u8eTeheistlesfound At a distance of two miles from the Foreland they became
useless. At three miles' distance the horns also became
useless. At a distance of four miles, with paddles stopped
Gun effective, and all on board quiet, they were wholly unheard. The 12
o'clock gun fired with a 1-pound charge at the Drop Fort in
Dover was well heard on May 19, when the horns and
whistles were inaudible. On this first day we noticed the
sudden and surprising subsidence of the sound as we ap-
proached the acoustic shadow lying beyond the line joining
the end of the Admiralty pier and the South Foreland. On
the 20th of May the permeability of the atmosphere by sound
had somewhat increased, but the steam-whistle failed to
pierce it to a depth of three miles. At four miles the
horns, though aided by quietness on board, were barely
heard. By careful nursing, if I may use the expression, the
horn-sounds were carried to a distance of six miles. The
superiority of the 18-pounder gun, already employed by the
Trinity House, over horns and whistles, was on this day so
decided as almost to warrant its recommendation to the
exclusion of all the other signals.
" Nothing occurred on the 2d of June to exalt our hopes
of the trumpets and whistles. The horns were scarcely
heard at a distance of three miles ; sometimes, indeed, they
failed to be heard at two miles. By careful nursing,
keeping everything quiet on board, they were afterward
carried to a distance of six miles. Long previously they
had ceased to be of use as fog-signals. Considering the
demands as to sound-range made by writers on this subject,
the demonstrated incompetence of horns and whistles of
great reputed power to meet these demands was not encour-
aging.
EUROPEAN LIGHT-HOUSE SYSTEMS. 43
" On the 3d of June the atmosphere had changed sur- June 3, acoustic
prisingly. It was loaded overhead with clouds of a dark
and threatening character ; the sounds, nevertheless, were
heard at a distance of three and three-fourths miles through
the paddle-noises, while with quietness on board they were
heard beyond nine miles.
"On June 10 the acoustic transparency of the air was
also very fair, the distance penetrated being upward of eight
and three-fourths miles. A large horn employed on this
day was heard at a distance of five miles through the pad-
dle-noises. The subsidence of the sound near the boundary
of the acoustic shadow on the Dover side of the Foreland
was to-day sudden and extraordinary, affecting equally both
horns and guns. We were warned to-day that the suprem- Supremacy of
, ,. , ., gun not invaria-
acy of the gun on one occasion by no means implied itsbie.
supremacy on all occasions ; the self-same guns which on the
20th had so far transcended the horns, being to-day their
equals and nothing more.
" The llth of June was employed in mastering still fur-
ther the facts relating to the subsidence of the sound east
and west of the Foreland, the cause of this subsidence
being in part due to the weakening of the sonorous waves
by their divergence into the sound-shadow, and in part, no
doubt, to interference.
" The atmosphere on the 25th of June was again very
defective acoustically. The sounds reached a maximum dis-
tance of six and a half miles. But at four miles, on returning
from the maximum distance, the sound was very faint. The
guns to-day lost still further their pre-eminence ; at five and a Guns inferior.
half miles their reports were inferior to the sound of the
horn. No sounds whatever reached Dover Pier on the llth,
and it was only toward the close of the day that they suc-
ceeded in reaching it on the 25th. Thus by slow degrees
the caprices of the atmosphere made themselves known to
us ; showing that even within the limits of a single day the
air, as a vehicle of sound, underwent most serious variations.
" The 26th of June was a far better day than its predeces-
sor, the acoustic range being over nine and one-quarter
miles. The direction of the wind was less favorable to the
sound on this day than on the preceding one, plainly prov-
ing that something else than the wind must play an impor-
tant part in shortening the sound-range.
" On the 1st of July we experimented upon a rotating horn, Juiy i, rotating"
and heard its direct or axial blast, which was found to behorn/
the strongest, at a distance of ten and one-half miles. The
sounds to-day were also heard at the Varne light-ship, which
44 EUROPEAN LIGHT-HOUSE SYSTEMS.
is twelve and three-quarters miles from the Foreland. The
atmosphere nad become decidedly clearer acoustically, but
not so optically, for on this day thick haze obscured the
white cliff's of the Foreland. In fact, on days of far greater
optical purity, the sound had failed to reach one-third of the
distance attained to-day. By the light of such a fact, any
attempt to make optical transparency a measure of acoustic
transparency must be seen to be delusive. On the 1st of
12 inch Ameri- July a 12-inch American whistle, of which we had heard a
can whistle. , , . . , . A ,
highly favorable account, was tried in the place of the 12-
inch English whistle ; but, like its predecessor, the perform-
ance of the new instrument fell behind that of the horns.
An interval of twelve hours sufficed to convert the acousti-
cally clear atmosphere of the 1st of July into an opaque
one ; for on the 2d of July even the horn -sounds, with pad-
dles stopped and all noiseless on board, could not penetrate
farther than four miles.
" Thus each succeeding day provided us with a virtually
new atmosphere, clearly showing that conclusions founded
upon one day's observations might utterly break down in
the presence of the phenomena of another day. This was
most impressively demonstrated on the day now to be refer-
red to. The acoustic imperviousuess of the 3d of July was
found to be still greater than that of the 2d, while the opti-
cal purity of the day was sensibly perfect. The cliffs of the
Extraordinary Foreland could be seen to-day at ten times the distance at
acoustic opacity . ..
with optical which they ceased to be visible on the 1st, while the sounds
were cut off at one-sixth of the distance. At 2 p. m. neither
guns nor trumpets were able to pierce the transparent air to
a depth of three, hardly to a depth of two miles. This ex-
traordinary opacity was proved to arise from the irregular
admixture with the air of the aqueous vapor raised by a
powerful sun.
"This vapor, though perfectly invisible, produced what
I have called an acoustic cloud impervious to the sound, and
from which the sound-waves were thrown back as the waves
of light are from an ordinary cloud. The waves thus refused
Echoes from transmission produced by their reflection echoes of extraor-
transparent air. djnary strength and duration. This I may remark is the
first time that audible echoes have been proved to be reflected
from an optically transparent atmosphere. By the low-
ering of the sun the production of vapor was checked, and
the transmissive power of the atmosphere restored to such
an extent that, at a distance of two miles from the Foreland,
at 7 p. m. the intensity of the sound was at least thirty-six
times its intensity at 2 p. m. Nothing requiring any notice
EUROPEAN LIGHT-HOUSE SYSTEMS. 45
here occurred cm July 4, when oar summer experiments
ended.
"On October 8 the observations were resumed, a steain- Octobers, ex-
. -111perimeut8 re-
siren and a Canadian whistle ot great power being added sumcd; siren.
to the list of instruments. A boiler had its steam raised to
a pressure of 70 pounds to the square inch. On opening a
suitable aperture this steam would issue forcibly in a con-
tinuous stream, and the sole function of the siren was to
convert this stream into a series of separate strong puffs.
This was done by causing a disk with twelve radial slits to
rotate behind a fixed disk with the same number of slits.
When the slits coincided a puff escaped ; when they did not
coincide the outflow of steam was interrupted. Each puff
of steam at this high pressure generated a sonorous wave
of great intensity, and the successive waves followed each
other with such rapidity that they linked themselves together
to a musical sound so intense as to be best described as a
continuous explosion.
u During the earlier part of October 8 the optical trans- sound im
parency of the air was very great; its acoustic transparency, pr
on the other hand, was very defective. Clouds blackened
and broke into a rain and hail shower of tropical violence.
The sounds, instead of being deadened, were improved by
this furious squall ; and, after it had lightened, thus less-
ening the local noises, the sound was heard at a distance of
seven and one-half miles, distinctly louder than it had been
heard through the preceding rainless atmosphere at a dis-
tance of five miles. Thus at five miles' distance the inten-
sity of the sound had been at least doubled by the rain, a
result obviously due to the removal by condensation and
precipitation of that vapor, the mixture of which with the
air had been proved so prejudicial to fog-signaling. We Dependence be-
established this day a dependence between the pitch of a plnetra^pow1
note and its penetrative power, the siren generating 480 er>
waves, being slightly inferior to the horns 5 while generating
400 waves a second it was distinctly superior. The chaage
in the atmosphere had been one favorable to the transmission
of the larger waves. The maximum range on October 8 was
nine miles. On October 9 the transmissive power had
diminished, the maximum range being seven and one-half
miles. On both these days the siren proved to be superior
to the horns, and on some occasions superior to the gun.
"On the 10th and llth, our steamer having disappeared, October 10 and
we made laud-observations. We found the duration of the
aerial echoes to be for the siren and the gun 9 seconds, for
the horns 6 seconds. The duration varies from day to day.
46 EUROPEAN LIGHT-HOUSE SYSTEMS.
We sought to estimate the influence of the violent wind
which had caused our steamer to forsake us upon the sound,
and found that the sound of the gun failed to reach us in
thewSiddSagainsttwo cases at a distance of 550 yards against the wind; the
sound of the siren at the same time rising to a piercing
intensity. To leeward the gun was heard at five times, and
certainly might have been heard at fifteen times, the dis-
tance attained to windward. The momentary character of
the gun-sound renders it liable to be quenched by a single
puff of wind; but low sounds generally, whether momentary
or not, suffer more from an opposing wind than high ones.
We had on the 13th another example of the powerlessness
of heavy rain to deaden sound.
" On the 14th the maximum range was ten miles, but the
atmosphere did not maintain this power of transmission.
It was a day of extreme optical clearness, but its acoustic
clearness diminished as the day advanced. In fact the sun
was in action. We proved to-day that by lowering the pitch
of the Canadian whistle its sound, which had previously
pitch and pene- been inaudible, became suddenly audible. The day at first
tration. wag favora5ie to the transmission of the longer sound-waves.
After the lapse of three hours the case was reversed, the
high-pitched siren being then heard when both gun and
horns were inaudible. But even this state of things did
not continue, so rapid and surprising are the caprices of
thev atmosphere. At a distance of five miles, at 3.30 p. m.,
the change in the transmissive power reduced the intensity
of the sound to at least one-half of what it possessed at
11.30 a. m., the wind throughout maintaining the same
strength and direction. Through all this complexity the
knowledge obtained on July 3 sheds the light of a principle
which reduces to order the apparent confusion.
October is; u October 15 was spent at Dungeness in examining the
DaboU'shorn. performance of DabolPs horn. It is a fine instrument, and
its application was ably worked out by its inventor ; still it
would require very favorable atmospheric conditions to
enable it to warn a steamer before she had come danger-
ously close to the shore. The direction in which the aerial
echoes return was finely illustrated to-day, that direction
being always the one in which the axis of the horn is
pointed.
October 16; su- " The 16th was a day of; exceeding optical transparency,
Sn!lty ° bebut of great acoustic opacity. The maximum range in the
axis was only five miles. On this day the howitzer and all
the whistles were clearly overmastered by the siren. It
was, moreover, heard at three and a half miles with the
EUROPEAN LIGHT-HOUSE SYSTEMS. 47
paddles going, while the gun was unheard at two and a half
miles. With no visible object that could possibly yield an
echo in sight, the pure aerial echoes, coming from the more
distant southern air, were distinct and long-continued at a
distance of two miles from the shore. Near the base of the
Foreland cliff we determined, their duration, and found it
to be 11 seconds, while that of the best whistle-echoes was
6 seconds. On this day three whistles, sounded simul-
taneously, were pitted against the siren, and found clearly
inferior to it. On the 17th four horns were compared with
the siren, and found inferior to it. This was our day of
greatest acoustic transparency, the sound reaching a maxi-
mum of fifteen , miles for the siren, and of more than six-
teen for the gun. The echoes on this day were audible for
a longer time than on any other occasion. They continued
for 15 seconds ; their duration indicating the atmospheric
depth from which they came.
"On October 18, though the experiments were not di-
rected to determine the transmissive-power of the air, we
were not without proof that it continued to be high. From
10 to 10.30 a. in., while waiting for the blasts of the siren
at a distance of three miles from the Foreland, the contin-
ued reports of what we supposed to be the musketry of
skirmishing parties on land were distinctly heard by us
all. We afterward learned that the sounds arose from the Rifle . practice
rifle-practice on Kingsdowii beach, five and a half miiesheard5imile8-
away. On July 3, which, optically considered, was a far
more perfect day, the 18-pounder howitzer and mortar
failed to make themselves heard at half this distance. The
18th was mainly occupied in determining the influence of
pitch and pressure on the siren-sound, Taking the fluctu-
ations of the atmosphere into account, I am of the opinion
that the siren, performing from 2,000 to 2,400 revolutions
a minute, or, in other words, generating from 400 to 480
waves per second, best meets the atmospheric conditions.
We varied the pressure from 40 to 80 pounds on the square
inch, and though the intensity did not appear to rise in
proportion to the pressure, the higher pressure yielded the
hardest and most penetrating sound.
" The 20th was a raiuv day with a strong wind. Up to a October ao; si-
ren superior in
distance of five and a half miles the siren continued to be rough weather.
heard through the sea and paddle noises. In rough weather,
indeed, when local noises interfere, the siren-sound far
transcends all other sounds. On various occasions to-day
it proved its mastery over both gun and horns. On the
21st, when the deputy master paid us a visit, the wind was
48 EUROPEAN LIGHT-HOUSE SYSTEMS.
strong and the sea high. The horn-sounds, with paddles
going, were lost at four miles; the siren continued service-
able up to six and a half miles. The gun to-day was com-
pletely overmastered. Its puffs were seen at the Foreland,
but its sound was unheard when the siren was distinctly
heard. Heavy rain failed to damp the power of the siren.
The whistles were also tried to-day, but were found far in-
ferior to the siren.
October 22; si- "On the 22d it blew a gale, and the Galatea quitted us.
when local noises We made observations on land on the influence of the wind
and of local noises. The shelter of the coast-guard station
at Cornhill enabled us to hear gun-sounds which were quite
inaudible to an observer out of shelter 5 in^the shelter also
both horn and siren rose distinctly in power, but they were
heard outside when the gun was quite unheard. As usual,
the sound to leeward was far more powerful than those at
equal distances to windward. The echoes from the cloud-
less air were to-day very fine. On the 23d, in the absence
of the steamer, the observations on the influence of the
wind were continued. The quenching of the gun-sounds, in
particular to windward, was well illustrated. All the
sounds, gun included, were carried much farther to lee-
.ward than to windward. The effect of a violent thunder-
increase OI
sound in rain, storm and downpour of rain in exalting the sound was
noticed by the observers both to windward and to leeward
of the Foreland. In the rear of the siren its range to-day
was about a mile. At right angles to the axis, and to wind-
ward, it was about the same. To leeward it reached a dis-
tance of seven and one-third miles.
" On the 24th, when observations were made afloat in the
steam tug Palmerston, the siren exhibited a clear mastery
over gun and horns. The maximum range was seven and
three-quarters miles. The wind had changed from west-
southwest to southeast, then to east. As a consequence
of this the siren was heard loudly in the streets of Dover.
On the 27th the wind was east-northeast ; and the siren-
sound penetrated everywhere through Dover, rising over
the moaning of the wind and all other noises. It was
heard at a distance of six miles from the Foreland, on the
road to Folkestone, and would probably have been heard
all the way to Folkestoce had not the experiments ceased.
Afloat and in the axis, with a high wind and sea, the siren,
and it only, reached to a distance of six miles ; at five miles
'^ was neard through the paddle-noises. On the 28th fur-
ther experiments were made on the influence of pitch j the
siren, when generating 480 waves a second, being found
EUROPEAN LIGHT-HOUSE SYSTEMS. 49
more effective than when generating 300 waves a second. /
The maximum range in the axis to-day was seven and one-
half miles.
" The 29th of October was a day of extraordinary optical
transparency, but by no means transparent acoustically. -
The gun was the greatest sufferer. At first it was barely
heard at five miles, but afterward it was tried at five and
one-half, four and one-half, and two and one-half miles, and
was heard at none of these distances. The siren at the
same time was distinctly heard. The sun was shining
strongly, and to its augmenting power the enfeeblemeut of
the gun-sound was probably due; wind from east- southeast
to east- northeast. At three and one-half miles subsequently,
dead to windward, the siren was faintly heard; the gun
was unheard at two and three-fourths miles. On land Mr.
Douglass heard the siren and horn sounds to windward at
two to two and one-half miles ; to leeward Mr. Edwards
heard them at seven miles, while Mr. Ayres, in the rear of
the instruments, heard them inland at a distance of five
miles, or five times farther than they had been heard on
October 23.
"The 30th of October furnished another illustration of October 30 ; at
the fallacy of the prevalent notion which considers optical S
and acoustic transparency to go hand in hand. The day r<
was very hazy, the white cliffs of the Foreland at the greater
distances being quite hidden ; still the gun and siren sounds
reached on the bearing of the Varne light- vessel to a dis-
tance of eleven and one-half miles. The siren was heard
through the paddle-noises at nine and one-fourth miles,
while at eight and one-half miles it became efficient as a
signal with the paddles going. The horns were heard at
six and one-fourth miles. This was during calm. Subse-
quently, with a roaring wind from the north-northwest, no
sounds were heard at six and one-half miles. At South
Sand Head the siren was very feeble, the gun and horns
being inaudible. The wind was here across the direction of
the sound. On laud, the wind being also across, the siren
was heard only to a distance of three miles northeast of the
Foreland; in the other direction it was heard plainly on
Folkestone Pier, eight miles distant; such was the in-
fluence of the wind. Both gun and horns failed to reach
Folkestone.
"Wind, rain, a rough sea. and great acoustic opacity October 31 ; si-
J ren superior un-
charactenzed October 31. Both gun and horns were un-derveryunfavor-
, able conditions.
heard three miles away. The siren at the same time was
clearly heard.. It afterward forced its sound with great
S. Ex. 54 - 4
ren
50 EUROPEAN LIGHT-HOUSE SYSTEMS.
s power through a violent rain-squall. Wishing the same in-
dividual judgment to be brought to bear on the sounds on
both sides of the Foreland, in the absence of our steamer,
which had quitted us for safety, I committed the observa-
tions to Mr. Douglass. He heard them at two miles on the
Dover side, and on the Sandwich side, with the same in-
tensity, at six miles.
"A gap, employed by me in preparing this report, and by
the engineers in making arrangements for pointing the
siren in any required direction, here occurs in our observa-
tions. They were, however, resumed on November 21,
when comparative experiments were made upon the gun
and siren. Both sources of sound, when employed as fog-
signals, will not unfrequently have to cover an arc of 180°,
and it was desirable to know with greater precision how
the sound in windy weather is affected by the direction in
which the gun or siren is pointed.
Effect of chang- <- The gun, therefore, was in the first instance pointed on
ing the line of
direction of si- us and fired, then turned and fired along a line perpendicu-
lar to that joining us and it. There was a sensible, though
small, difference between the sounds which reached us in
the two cases. A similar experiment was made with the
siren, and here the falling off, when the instrument was
pointed perpendicular to the line joining us and it, was very
considerable. This is what is to be expected, for the
trumpet associated with the siren is expressly intended to
gather up the sound and project it in a certain direction,
while no such object is in view in the construction of the gun.
Hence any deviation from that direction must, in the case
of the siren, be attended with a greater weakening of the
sound than in the case of the gun. The experiments here
referred to were amply corroborated by others made on No-
vember 22 and 23.
"On both of these days the Galatea's guns were fired both
Aerial echoes, to wind ward and to leeward. The aerial echoes in the latter
case were distinctly louder and longer than in the former.
" In front of the Oornhill coast-guard station, and only
one and one-fourth miles from the Foreland, the siren, on
the 21st, though pointed toward us, fell suddenly and con-
siderably in power. Before reaching J)over Pier it had
ceased to be heard. The wind was here against the sound ;
but this, though it contributed to the effect, could not account
for it, nor could the proximity of the shadow account for it. To
these two causes must have been added a flocculent atmos-
phere. The experiment demonstrates conclusively that
there are atmospheric and local conditions which when coin-
EUROPEAN LIGHT-HOUSE SYSTEMS. 51
bined prevent our roost powerful instruments from making
more than a distant approach to the performance which
writers on fog-signals have demanded of them.
" On November 24 the sound of the siren pointed to co°™gj;f 2ol-
windward was compared at equal distances in front of and
behind the instrument. It was louder to leeward in the rear of sound.
than at equal distances to windward in front. Hence in a
wind the desirability of pointing the instrument to wind-
ward. The whistles were compared this day with the siren
deprived of its trumpet. The Canadian and the 8-inch
whistles proved the most effective, but the naked siren was
as well heard as either of them. As regards opacity, the
25th of November almost rivaled the 3d of July. The gun
failed to be heard at a distance 2.8 miles ; it yielded only a
faint crack at two and one-half miles. This, as on July 3,
was when the air was calm. A revival of the wind subse-
quently brought with it a revival of the sound.
*******
" While the velocity of sound has been the subjects of refined 80Jj^f nsity of
and repeated experiments, I am not aware that since the
publication of a celebrated paper by Doctor Derham, in the pe?erham'8 pa~
Philosophical Transactions for 1708, any systematic inquiry
has been made into the causes which affect the intensity of
sound in the atmosphere. Derham's results, though ob-
tained at a time when the means of investigation were very
defective, have apparently been accepted with unquestion-
able trust by all subsequent writers; a fact which is, I
think, in some part to be ascribed to the a priori probability
of his conclusions.
" Thus Doctor Robinson, whom I have already quoted, * * Dr.
_ , statement.
relying apparently upon Derham, says : ' Fog is a powerful
damper of sound;' and he gives a physical reason why it
must be so. ' It is a mixture of air and globules of water, and
at each of the innumerable surfaces where these two touch,
a portion of the vibration is reflected and lost.' And he adds
further on, < The remarkable power of fogs to deaden the re-
port of guns has been often noticed.'
"Assuming it, moreover, as probable that the measure of
1 a fog's power in stopping sound' bears some simple rela-
tion to its opacity for light, Dr. Robinson, adopting a sug-
gestion of Mr. Alexander Cunningham, states that 'the dis-
tance at which a given object, say a flag or pole, disap-
pears may be taken as a measure of the fog's power' to ob-
struct the sound. This is quite in accordance with prev-
alent notions, and, granting that the sound is dissipated,
as assumed, by reflection from the particles of fog, the con-
52 EUROPEAN LIGHT-HOUSE SYSTEMS.
elusion follows that the greater the number of the reflecting
particles the greater will be the waste of sound. But the
number of particles, or, in other words, the density of the
fog, is declared by its action upon light ; hence the optical
opacity will be a measure of the acoustic opacity.
These opinions *« This I say expresses the opinion generally entertained :
SDOWH to be crro- j*ii»^i» -IT
neous. < clear still air ' being regarded as the best vehicle for sound.
We have not, as stated above, experimented in really dense
fogs, but the experiments that we have made entirely de-
stroy the notion that clear weather is necessarily better for
the transmission of sound than thick weather. Some of our
days of densest acoustic opacity have been marvelously
clear optically, while some of our days of thick haze have
shown themselves highly favorable to the transmission of
sound. Were the physical cause of the sound-waves that
above assigned, did that waste arise in any material de-
gree from reflection at the limiting surfaces of the particles
of haze, this result, as I have already pointed out, would be
inexplicable.
railing rain as "Again, Derham, as quoted by Sir John Herschel, says
that ' falling rain tends powerfully to obstruct sound.7 We
have had repeated reversals of this conclusion. Some of
our observations have been made on days when rain and
hail descended with a perfectly tropical fury, and in no
single case did the rain deaden the sound. In every case,
indeed, it had precisely the opposite effect.
railing snow. << But falling snow, according to Derham, offers a more se-
rious obstacle than any other meteorological agent to the
transmission of sound. We have not extended our observa-
tions at the SouthForelaudintosuowy weather. But I may be
the Merde Giace. permitted to refer to an observation of my own which bears-
directly upon this point. On Christmas night, 1859, 1 reached
Chamouni, through snow so deep as to obliterate the road-
fences. On the 26th and 27th it fell heavily. During a lull
in the storm I reached the Montanvert, sometimes breast-
deep in snow. On the 29th the entry in my journal is i Snow,
heavy snow ; it must have descended through the entire
night, the quantity freshly fallen is so great.7 Dr. Derham
had referred to the deadening effect produced by a coating
of fresh-fallen snow upon the ground, alleging that when
the surface was glazed by freezing the damping of the sound
disappeared.
" Well, on December 29, 1 took up a position beside the
Mer de Glace, with a view to determine its winter motion,
and sent my assistants across the glacier with instructions
to measure the displacement of a transverse line of stakes
EUROPEAN LIGHT-HOUSE SYSTEMS. 53
planted previously in the snow. I was standing at the time
beside my theodolite, with snow 4 feet deep around ine.
A storm drifted up the valley, darkening the air as it ap-
proached. It reached us, the snow falling more heavily
than ever I had seen it elsewhere. It soon formed a heap on
my theodolite; still through the telescope I was able to
pick up at intervals the retreating forms of my men. Here
there was a combination of thick snow in the air and of soft
fresh snow on the ground, such as Derham had hardly en-
joyed. Through such an atmosphere, however, I was able .
with my unaided voice to make my instructions audible for
half a mile, while the experiment was rendered reciprocal by
one of my men making his voice audible to me.
* * * * * * *
" The real enemy to the transmission of sound through neo^s°°aho™0t^6e"
the atmosphere has, I think, been clearly revealed by the cause of acoustic
foregoing inquiry. That enemy has been proved to be not °P
rain, nor hail, nor haze, nor, I imagine, fog or snow ; not
water, in fact, in either a liquid or a solid form, but water in
a vaporous form, mingled with air, so as to render it acous-
tically turbid and flocculent. This acoustic turbidity often
occurs on days of surprising optical transparency. Any
system of measures, therefore, founded on the assumption
that the optic and acoustic transparency of the atmosphere
go hand in hand must prove delusive.
" There is but one solution of this difficulty: it is to make
the source of sound so powerful as to be able to endure con-
siderable loss by partial reflection and still retain a sufficient
residue for transmission. Of all the instruments hitherto thf"?ren°rity °f
examined by us the siren comes nearest to the fulfillment
of this condition. Its establishment upon our coast will, in
my opinion, prove an incalculable boon to the mariner.
* * *****
u We had, as already stated, been favored with thunder, NO experiments
hail, rain, and haze, but not with dense fog. All the more denseefog.ma
anxious was I to turn the recent excellent opportunity to
account. On Tuesday, December 9. 1 therefore telegraphed
to the Trinity House, suggesting some gun-observations. A
prompt reply informed me that such observations would be
made in the afternoon at Blackwall or in its neighborhood.
* * * * * * *
" Slowly, but surely, we thus master this question. And F0gs do not
the further we advance the more we are assured that our deaden 80untl-
reputed knowledge regarding it has been erroneous from
beginning to end. Fogs, like rain, have no such power
54
EUROPEAN LIGHT-HOUSE SYSTEMS,
Experiments in
Hyde . irk, Lon-
December si.
January 22.
to deaden sound as, since the time of Derham, has been
universally ascribed to them.
# * # * * * *
"An assistant placed at the end of the Serpentine sounded
^e w]1istie and pipe for fifteen minutes without interrup-
tion. An observer at the bridge noticed the fluctuations of
the sound. Sometimes the whistle was heard alone, some-
times the organ-pipe. Sometimes both whistle and pipe
began strongly and ended by sinking almost to inaudibility.
Extraordinary fluctuations were also observed in the peal
of bells, to which reference has been already made. In a
few seconds they would sink from a loudly ringing peal into
utter silence, from which they would rapidly return to loud-
tougued audibility. The intermittent drifting of fog over
the sun's disk, by which his light is at times obscured, at
times revealed, is, as already stated, the optical analogue
of these acoustical effects. In fact, as regards such changes,
the acoustic deportment of the atmosphere is a true tran-
script of its optical deportment.
* * * * * * *
" On December 31 1 went to the end of the Serpentine,
at noon, to listen to the Westminster bell. Not one of the
twelve strokes was audible, nor were the chimes heard. On
several of the first days of this year I placed myself beside
the railing of St. James's Park, near Buckingham Palace,
and waited at noon for the stroke of the bell ; it was quite
unheard. These days were moist and warm, the air was
calm, and the clock -tower in sight. On January 19 1 placed
myself in the same position ; fog and drizzling rain obscured
the tower $ still I heard not only the strokes of the big bell,
but also the preceding chimes of the quarter-bells. The air
was calm at the time.
" During the exceedingly dense and < dripping ' fog of Jan-
uary 22 I placed myself near the same railings, and heard
every stroke of the bell. On the same day I sent an assist-
ant to the end of the Serpentine, and when the fog was
densest he heard the Westminster bell striking loudly
eleven. Toward evening this fog began to melt away, and
at 6 o'clock I went to the end of the Serpentine to observe
the effect of the clearing of the atmosphere upon the sound.
Not one of the strokes reached me. At 9 o'clock, and at 10
o'clock, my able assistant, Mr. Cottrell, was in the same
position, and on both occasions failed to hear a single stroke
of the bell. It was a case precisely similar to that of De-
cember 13, when the dissolution of the fog was accompanied
by a decided acoustic thickening of the atmosphere. All
EUROPEAN LIGHT-HOUSE SYSTEMS. 55
this shows what instructive results are to be obtained in
connection with the transmission of sound through the
atmosphere from a mode of observation accessible to all.
"This opportune fog enabled us to remove the last of amo^e<Jor8 re"
congeries of errors which, ever since the year 1708, have
attached themselves to this question. As regards phonic
coast- signals, we now know exactly where we stand; and,
through the application of this knowledge to maritime pur- ,
poses, a meteorological phenomenon, which was bewailed
in London as an unmitigated evil, may in the end redound
to the advantage of the public.
" Since the publication of the first notices of this investi- Portland guns
gation various communications have reached me, to one or SSies f°through
two of which I should like to refer. The Kev. George H.densefog
Hetling, of Fulham, has written to me with a circumstan-
tiality which leaves no room for doubt, that he has heard
the Portland guns at a distance of forty-four miles through
a dense fog.
"The Duke of Argyll has also favored me with the fol- statement of
, „ , . . !n • .^i tho Duke of Ar-
lowmg account of his own experience. Coming as it does gyii.
from a disciplined scientific observer, it is particularly val-
uable. i This fact [the permeability of fog by sound] I
have long known, from having lived a great part of my life
within four miles of the town of Greenock, across the Frith.
Ship-building goes on there to a great extent, and the ham-
mering of the calkers and builders is a sound which I have
been in the habit of hearing with every variety of distinct-
ness, or of not hearing at all, according to the state of the
atmosphere ; and I have always observed on days when the
air was very clear, and every mast and spar was distinctly
seen, hardly any sound, was heard, whereas on thick and
foggy days, sometimes so thick that nothing could be seen,
every clink of every hammer was audible and appeared
sometimes as close at hand. This has been long a very
familiar experience with me.7
"It is hardly necessary for me to say a word to guard The real bar-
inyself against the misconception that I consider sound toSon.to
be assisted by the fog itself. Fog I regard as the visible
result of an act of condensation, which removes the real
barrier to transmission, that barrier being aqueous vapor
so mixed with air as to render it acoustically fiocculent or
turbid. The fog-particles appear to have no more influence
upon the waves of sound than the suspended matter stirred
up over the banks of Newfoundland has upon the waves of
the Atlantic.
56 EUROPEAN LIGHT-HOUSE SYSTEMS.
superiority of "Ail absolutely uniform superiority on all days cannot be
conceded to any one of the instruments subjected to exami-
nation 5 still, our observations have been so numerous and
long-continued as to enable us to come to the sure conclu-
sion that, on the whole, the steam-siren is beyond question
the most powerful fog-signal which has hitherto been tried
in England. It is specially powerful when local noises,
^ such as those of wind, rigging, breaking waves, shore-surf,
and the rattle of pebbles have to be overcome. Its density,
quality, pitch, and penetration render it dominant over such
noises after all other'signal-sounds have succumbed.
" I do not hesitate to recommend the introduction of the
siren as a coast-signal.
change in " It will be desirable in each case to confer upon the in-
Srabu? sir6n strurnent a power of rotation, so as to enable the person in
charge of it to point its trumpet against the wind, or in any
other required direction. This arrangement has been made
at the South Foreland, and it presents no mechanical diffi-
culty. It is also desirable to mount the siren so as to per-
mit of the depression of its trumpet 15° or 20° below the
horizon.
Position of fog- " I*1 selecting the position at which a fog-signal is to be
signal. mounted, the possible influence of a sound-shadow, and the
possible extinction of the sound by the interference of the
direct waves with waves reflected from the shore, must form
the subject of the gravest consideration. Preliminary trials
may in most cases be necessary before fixing on the precise
point at which the instrument is to be placed.
'
siren, with u ^ne form of the siren which has been longknown to sci-
compressed air. entific men is worked with air, aucVit would be worth while
to try how the fog-siren would behave supposing com-
pressed air to be substituted for steam. Compressed air
might also be tried with the whistles.
Robinson's " ^° fog-signal hitherto tried is able to fulfill the condi-
fuimied^by ann°y tio11 laid d°wn by I>r- Robinson, * * * namely. ' that all
fog-signal. fog-signals sliould ~be distinctly audible for at least four miles
under every circumstance.' Circumstances may arise to pre-
vent the most powerful sounds from being heard at half
this distance. What may with certainty be affirmed is, that
in almost all cases the siren, even on steamers with paddles
going, may be relied on at a distance of two miles ; in the
great majority of cases it may be relied upon at a distance
of three miles, and in the majority of cases at a distance
greater than three miles.
EUROPEAN LIGHT-HOUSE SYSTEMS. 57
" Happily, the experiments thus far made are perfectly ejjjg|j£8
concurrent in indicating that at the particular time when fog.
fog-signals are needed, that is, during foggy weather, the
air in which the fog is suspended is in a highly homogeneous
condition $ hence it is in the highest degree probable that
in the case of fog we may rely upon these signals being
effective at much greater distances than those just men-
tioned.
" I say i probable,' while the experiments seem to render
this result certain. Before pronouncing it so, however, I
should like to have some experience of warmer fogs than
those in which the experiments have hitherto been made.
That the fog- particles themselves are not sensibly injurious
to the sound has been demonstrated ; but it is just possible
that in' warm weather the air associated with the fog may
not be homogeneous. I would recommend the experiment
necessary to decide this point to be made on some of the
fogs of the early summer.
"I am cautiousnot to inspire the mariner with a confidence Distance at
-r-i-r, , -, f, • T i which a signal
which may prove delusive. When he hears a tog-signal he should be heard,
ought, as a general rule, at all events until extended expe-
rience justifies the contrary, to assume the source of sound
to be not more than two or three miles distant, and to take
precautions accordingly.
"Once warned, he may, by the heaving of the lead or
some other means, be enabled to check his position. But
if he errs at all in his estimate of distance, it ought to be on
the side of safety. .
" Unless very cogent practical reasons can be adduced in intervals be-
tween blasts,
its favor, I should strongly deprecate a lengthened interval
between the siren-blasts. My own small experience has
shown me how harassing to the mariner are some of our
revolving lights with a long period of rotation. 'No light,
in my opinion, ought to be obscured for more than 30 sec-
onds, and the interval between the two blasts of our fog-
signal ought not to be longer.
"With the instruments now at our disposal, wisely estab-
lished along our coasts, 1 venture to believe that the saving
of property in ten years will be an exceedingly large mul-
tiple of the outlay necessary for the establishment of such
signals. The saving of life appeals to the higher motives
of humanity."
* *= * # # # #
General Duane, of the Corps of Engineers of the Army Report from
and light-house engineer of the New England coast, for- G
warded to the Light- House Board on January 12, 1872, a
58 EUROPEAN LIGHT-HOUSE SYSTEMS.
report which corroborates the results of Professor TyudalFs
experiments, some of which were foreshadowed iri his treatise
on Sound, published in '1867. This report contains much
practical information in regard to fog-signals, and it is to
be regretted that it has not been published. The following
are extracts from General Duane's report:
*******
Fog-signais on " There are six steam fog- whistles on the coast of Maine.
the, Maine coast. Tliese nave beeu frequently heard at a distance of twenty
miles, and as frequently cannot be heard at the distance of
two miles, and this with no perceptible difference in the
state of the atmosphere.
signal some- " The signal is often heard at a great distance in one
in™nse tocS? direction, while in another it will be scarcely audible at the
distance of a mile. This is not the effect of wind, as the
signal is frequently heard much farther against the wind
than with it. For example, the whistle on Cape Elizabeth
can always be distinctly heard in Portland, a distance of
nine miles, during a heavy snow-storm, the wind blowing a
gale directly from Portland toward the whistle.
Beit impene- "The most perplexing difficulty, however, arises from
Soundin^he the fact that the signal often appears to be surrounded by
a belt, varying in radius from one to one and a half miles,
from which the sound appears to be entirely absent.
sound lost for " Thus, in moving directly from a station, the sound may
thence audible for the distance of a mile, is then lost for about
the same distance, after which it is again distinctly heard
for a long time. This action is common to all ear-signals,
and has been at times observed at all the stations, at one
of which the signal is situated on a bare rock twenty miles
from the main-land, with no surrounding objects to affect
the sound. All attempts to re enforce the sound by means
of reflectors have hitherto been unsuccessful. Upon a
large scale sound does not appear, on striking a surface, to
be reflected after the manner of light and heat, but to roll
along it like a cloud of smoke.
* * * * * * *
" -^rom au attentive observation during three years of the
fog-signals on this coast, and from the reports received
from captains and pilots of coasting-vessels, I am convinced
that in some conditions of the atmosphere the most power-
ful signals will be at times unreliable.
* ***** *
Reflection at- " ]STow, it frequently occurs that a signal, which under or-
dinary circumstances would be audible at the distance of
fifteen miles, cannot be beard from a vessel at the distance
EUROPEAN LIGHT-HOUSE SYSTEMS. 59
of a single mile. This is probably due to the reflection
mentioned by Humboldt.
" The temperature of the air over the land where the fog-
signal is located being very different from that over the
sea, the sound, in passing from the former to the latter,
undergoes reflection at their surfaces of contact. The cor-
rectness of this view is rendered more probable by the fact
that when the sound is thus impeded in the direction of the
sea, it has been observed to be much stronger inland.
" When a vessel approaches a signal in a fog a difficulty Difficulty in
. determining posi-
is sometimes experienced in determining the position of the tion of the signal,
signal by the direction from which the sound appears to
proceed, the apparent and true direction being entirely
different. This is undoubtedly due to the refraction of
sound passing through media of different density.
" Experiments and observation lead to the conclusion Reason for the
that these anomalies in penetration and direction of sound to exist**
from fog-signals are to be attributed mainly to the want of
uniformity in the surrounding atmosphere, and that snow,
rain, fog, and the force and direction of the wind have much
less influence than has generally been supposed."
While this report is passing through the press, Sir Fred-
erick has also kindly sent me a copy of his memorandum to
the Elder Brethren of the Trinity House concerning the re-
port of Professor Tyndall, and it will be found below.
MEMORANDUM BY SIR FREDERICK ARROW, THE DEPUTY
MASTER OF THE TRINITY HOUSE, UPON DR. TYNDALI/S
REPORT ON THE EXPERIMENTS AT' SOUTH FORELAND.
"At the close of a series of important investigations,
undertaken with the desire of adding to the safety of navi-
gation round our seaboard, to which a committee of the
Elder Brethren, acting in concert with the corporation's
scientific adviser, have devoted many months of careful
attention, it will be convenient, now that the report of Dr.
Tyndall has been presented to the board, to consider how
far the conclusions arrived at may be practically and use
fully applied.
u Before entering, however, upon the subject-matter of the
report, it is due to the members of the committee, who have
freely sacrificed their time and comfort during a protracted
period, that the board should record its acknowledgment
of their careful prosecution of a long and arduous duty.
60 EUROPEAN LIGHT-HOUSE SYSTEMS.
And if this acknowledgment is due .to the members of the
committee, much more is to be accorded to their distin-
guished scientific guide, Dr. Tyndall, who at great incon-
venience to himself, with serious encroachment on his valu-
able time, and frequently some personal discomfort, has
applied himself to this investigation with characteristic
patience and perseverance. Step by step, after repetitions
almost wearying to those unversed in such trained and dis-
passionate habits of procedure, the conditions affecting the
traveling-power of sound have become clearer and clearer,
old errors have been corrected, and a great advance has
been made toward accurately estimating the value of sound-
signals; and the important knowledge has been acquired
that the seaman's greatest enemy affords in itself aid to
mitigate its worst evils.
" To Mr. Douglass also and his assistants much credit is
due for the very thorough and efficient manner in which
they performed their duties in connection with this inquiry,
and Mr. Douglass's assistance as a practical observer on
board the yachts has throughout the experiments been of
great service.
u Observations at sea were commenced on the 19th of
May, 1873, after some months previously employed by the
engineering department in mounting the requisite instru-
ments, (the selection of which was based upon the report of
the committee who had visited the fog-signal establishments
of the North American seaboard,) and in making such
arrangements as were suggested by the experience of the
Elder Brethren and Mr. Douglass or by the views of Dr.
Tyndall on the subject. From that time to the 21st of Feb-
ruary, 1874, on shore and at sea the observations have been
going on at short intervals, and frequently for weeks
together.
" Foremost among the practical results is the important
fact before alluded to, viz, that fog does not impede the
transmission of sound, (as has long been supposed ;) indeed,
it is shown that a foggy atmosphere is a highly favorable
condition for the traveling of the sound-wave; further,
during heavy, blinding rain or snow storms the passage
of sound through the air is not obstructed ; indeed, the
observations of the committee in the former case record an
increase in the power of the sound either during or immedi-
ately after a rain-storm ; while the evidence of Dr. Tyndall
of his Alpine experience with regard to falling snow may be
accepted as proving the latter. It may safely be concluded,
EUROPEAN LIGHT-HOUSE SYSTEMS. 61
therefore, that whenever the state of the weather is such as
to render sound- signals necessary, the atmospheric condi-
tions are most favorable for their efficient application, and
it may also be concluded that, under the conditions of
weather above referred to, the range of the signals will be
much greater than the limit laid down in the report as the
result of the general observations.
"Turning to the action of the wind upon sound, the report
confirms all previous experience, and shows that the most
powerful sound fails to penetrate the opposing force of a
strong wind to any considerable distance ; but it is satis
tory to be assured that even against a moderate gale and
unfavorable conditions for sound-transmission signals may
be relied on for sending sound to a distance of two or three
miles, and, under ordinary conditions of fog, considerably
farther. Having regard, howrever, to the variability of the
sound-range of the same instrument on different days,
attributable to the varying conditions of the atmosphere, it
is not possible to assert positively that any signal has an
absolute range which may be relied upon at all times. The
practice of the Elder Brethren of not publishing in their
notices of fog-signals a maximum range of audibility, or of
accepting isolated instances as every-day occurrences, is
therefore amply justified. Happily long ranges are not
very necessary, inasmuch as the mariner does not need to
hear a sound-signal at ten, fifteen, qr twenty miles. Dr.
Tyndall quotes, in relation to this part of the subject, an
opinion expressed by our late scientific adviser, Professor
Faraday, that 4a false promise to the mariner would be
worse than no promise at all.' The Brethren need scarcely
be reminded that in so saying our dear and venerated friend
was simply giving utterance to the standard axiom of the
Trinity House, as old, perhaps, as the corporation itself,
viz, that safety is only to be found in certainty, and that
anything which does not secure the latter condition is a
foe, rather than a friend, to the mariner.
u Bearing in mind, therefore, the liability to atmospheric
interference under ever-varying conditions, as shown in the
report, attention must next be directed to the instruments
used in the investigation and the conclusions arrived at
with regard to each of them, so far as the inquiry has now
advanced.
" The instruments tried were the American siren, Holmes's
trumpets, American, Canadian, and English steam-whistles,
and three guns. The effects obtained from all these instru-
ments have varied in a remarkable manner at different
62 EUROPEAN LIGHT-HOUSE SYSTEMS.
times, but for general efficiency there is no doubt that the
American siren takes the first place. It has shown the
greatest penetrative power, especially where local noises
have to be overcome, but at present it has the drawback of
being worked by steam at the high pressure of 70 pounds,
which is not only a serious element of danger, but entails
considerable expense for fuel and labor. Mr. Douglass,
however, tells us that the caloric-engine will work the siren,
and he confidently anticipates being able to do away with
steam altogether, and so to render this instrument a safe,
economical, and efficient signal for general adoption.
" The air-trumpet has also shown itself to be an efficient
instrument, superior to the whistles and sometimes equal-
ing the siren. Its chief advantage is that it is blown by
means of the caloric-engine at something over 20 pounds7
pressure, and can be worked without skilled labor, and,
avoiding the danger attendant upon the employment of
steam or gunpowder, combines safety with economy ; and
its clear, musical note may be an element of distinctiveness
capable of being developed so as to make it ultimately of
some service in this respect. In actual practice there are
one or two drawbacks to the use of reed-instruments, such
as the difficulty of tuning, liability of reeds cracking, &c.
Such contingencies are not likely to arise in regard to the
siren, and if the economy and simplicity of working by
means of the caloric-engine can be also applied to the more
powerful siren, it seems clear that the result will be highly
advantageous as a most useful combination of power, safety,
and economy well suited for fog-signal purposes. Never-
theless the satisfactory performance of the trumpets during
the late trials fully justifies their present employment as
fog-signals.
" Not so much can be said in favor of whistles. Through-
out the trials their marked inferiority to the other instru-
ments has been recorded. The American whistle, yielding
a harsh roar, when close at hand was deafening, but its
sound failed to penetrate to any useful distance.* The Ca-
nadian whistle appears to have been better, but it also
failed in general effective power, although occasionally it
was heard a great distance, even obtaining superiority over
the other instruments, but this was of very rare occurrence.
As a rule, the whistles were behind the siren, trumpet, and
gun, and seem to have been dependent, more than the other
instruments, on exceptional atmospheric conditions for
* This statement does not agree with our experience in the practical
use of a large number of steam fog-whistles on the seacoast of the United
States.— E.
EUROPEAN LIGHT-HOUSE SYSTEMS. 63
yielding their best results. The general conclusion seems
to be that for practical purposes the steam-whistles, as at
present tried, are not proved to be advantageous as fog-
signals.
" With respect to the usefulness of guns, it appears from
the report that 'they possess certain disadvantages, viz,
the short duration of the sound, the liability of that sound
to be quenched by local noises, and its comparative ina-
bility to cope with an opposing wind. Dr. Tyndall never-
theless ranks the gun as a first-class signal, an opinion
which long experience of its use confirms. The gun, as a
signal, is well known to mariners, while the flash is also
said to be of service in thick weather. With regard to the
guns used in the experiments, it appears that the short 5J-
iuch howitzer, with a 3-pound charge, is superior to the
long 18-pounder or the 13-inch mortar with the same charge,
the howitzer having generally yielded a louder and more
effective report. The subject of a special gun for fog-signal
purposes is now under consideration, and it seems probable
that both in effective power and facility of working, the
gun may be rendered considerably more serviceable than
hitherto.
"From the foregoing observations it will be seen that at
present there are three kinds of instrument practically avail-
able fc>r future service as fog-signals, viz, the siren, the trum-
pet, and the gun, and as further experience is gained with
regard to these instruments, it may reasonably be expected
that great improvement will be made in them and that the
future results to be obtained from them will surpass those
now recorded.
" It will be well now to consider briefly one or two points
in connection with the selection of a site for, and the instru-
ment to be used as a fog-signal, when the locality has been
determined upon. In the investigations the question as to
the height above the sea at which it is desirable that a sig-
nal should be placed has received some attention, and the
results show that it is advantageous that such signals should
be placed at a considerable height above the sea-level in or-
der to avoid the interference caused by the noise of waves
breaking on the shore, the rattle of pebbles, &c. The com-
parative trial made between a pair of horns on the summit
of the South Foreland cliff and another pair 200 feet below,
close to the sea- surf ace, proved with scarcely an exception
that the higher horns were superior to the lower ones. From
this it would appear advisable, where possible, to place the
signal high above the sea, but there are positions on our
64 EUROPEAN LIGHT-HOUSE SYSTEMS.
coasts where fog-signals are necessary, and yet where no
considerable elevation could be obtained, notably Duuge-
ness, Orfordness, &c. For such positions, therefore, a large
and powerful siren would be very suitable as being able to
overcome the noises of the sea-shore. For river-banks, light-
vessels, and other places undisturbed by interfering noises,
a smaller instrument of the same description, or a trumpet,
would prove serviceable, and the gun would be a fit signal
for such places as are of some elevation clear above the sea,
without adjacent outlying rocks, and which vessels may ap-
proach i close to.7 It is not intended in the above sugges-
tions to lay down any system which shall be invariably fol-
lowed in the allocation of fog signals, but, having regard to
the performances of the instruments referred to as shown in
the report, the foregoing observations may be regarded as
indicating to some extent how the respective merits of the
instruments may be most usefully applied.
u While upon the subject of fog-signal sites allusion may
be made to the caution conveyed in the report that in select-
ing the position for a fog-signal the possible influence of
sound-shadow must be taken into account. This is a point
to which reference was made in the report of your committee
to America, it being therein recorded that in the experi-
ments carried out at Portland Bay, United States,* the effect
of a sound-shadow was distinctly experienced, and four
committee stated in their report that i in selecting the site
fora fog-signal care must be taken that no outlying point
or cliff shall interfere with the arc of sound.' It is satisfac-
tory to find the conclusion of that committee on this point
entirely borne out by the investigations of another.
" Another important conclusion to be drawn from this
report in regard to the question of sites is that no signal
should be required to mark dangers extending seaward more
than a mile or a mile and a quarter. The minimum effect-
ive range of a signal being 2^ miles, vessels approaching
such dangers and coming into the sound-range would have
room to maneuver and be able to keep at a safe distance.
This is, of course, taking the minimum range of the signals,
as stated in the report, but it is more than probable, as has
been stated previously, that in foggy weather, the sound-
range being extended farther than the minimum limit re-
ferred to, a larger range may be allowed.
" Another important consideration has to be borne in mind,
viz, the direction in which sound should be projected. As
*The experiments referred to have been carried on from time to time
for some years, under tlie direction of Professor Henrj. — E.
EUROPEAN LIGHT-HOUSE SYSTEMS. 65
the sound of a signal is ascertained to be most effective in.
the line of its axis, it follows that the instrument should be
capable of such adjustment that its strongest sound may be
projected directly against the opposing wind.
u It is to be observed that on another point these experi-
ments confirm the opinions expressed by your committee to
America, for, with regard to the question of distinctions, it
is clearly shown that it is not possible to rely upon dis-
tiuctiveuess of note alone, for the mariner would not appre-
ciate such a distinction ; indeed the siren, horns, and
whistles have invariably been spoken of by sailors in the
vicinity as " the fog-horns." Between the report of the gun
and the sound of the siren or the trumpet there is a perfectly
intelligible difference ; but for further purposes of distinction
for the latter instruments, variation of the length of the
silent interval between each blast offers the most satisfac-
tory means. With regard to this point it will be seen that
Dr. Tyndall has, with some reservation, expressed an opin-
ion which hardly seems to harmonize with the experience
of the Elder Brethren. Dr. Tyndall would restrict the
silent interval to a length of 30 seconds, and in support of
his opinion draws an analogy between the action of the eye
and the ear, which does not commend itself to actual nauti-
cal experience. The board will probably not be disposed
to waive a clear advantage in power and great scope for
distiuctiveuess, in order that the longest interval of silence
should not exceed 30 seconds, especially with the knowl-
edge that guns fired at intervals of a quarter of an hour
have proved of great service to the mariner hitherto.
"A general review of the entire report shows that a con-
siderable amount of knowledge has been gained, both as to
the influence of the atmosphere in the transmission of sound
and to what extent the appliances we possess may be relied
on for producing such sounds as will be of practical service
to the mariner. We have learned something of our igno-
rance in regard to sound-transmission. We now know that
the varying conditions of the atmosphere render no judg-
ment infallible, and that conclusions founded on the ex-
perience of to-day, are not trustworthy for estimating the
results of the morrow. We know, moreover, that after
bringing forward all the aid which science can at present
give to guide the mariner in thick weather, there is still a
large element of uncertainty and mystifying influence with
which he has to combat, and which renders it incumbent
on him to use the greatest caution and prudence in thick
S. Ex. 54 5
66 EUROPEAN LIGHT-HOUSE SYSTEMS.
weather, to regard and make use of the sound-signals as
means for assuring the vessel's position, and not as aids for
running at high speed ; and, above all, never to trust so
implicitly to sound-signals as to neglect the use of the sea-
man's best friend and truest guide, the lead.
" The subject of fog-signals has by means of this investi-
gation received a great impetus. It may fairly be said that
we have taken a considerable step in advance, and it only
remains to follow it up. As we go forward our experience
will widen, and although it is more than probable that a
few years of practical experience and testing of fog-signals
will materially modify our present views, and improve con-
siderably the instruments we have, yet we now know Jwiv
to go forward and in what direction to head our efforts. It
is to be hoped that before very long our coasts will be
guarded by a complete chain of sound-signals, all effective
and useful to the mariner. No unnecessary delay need now
occur before proceeding to supply the light-ships and the
important stations already selected by the board, and when
they are all established the lights rendered useless at a
quarter of a mile by fog will be superseded by sound-signals
capable of warning the mariner at a distance of three miles.
" It is almost unnecessary to add that in thus giving
practical effect to the spirit of the recommendations of this
valuable report, the Elder Brethren will have the satisfac-
tion of knowing they are acting in the highest interests of
humanity and conferring an inestimable boon on the nauti-
cal community at large."
SOUTH FORELAND.
Location Tlie great electric lights at South Foreland, two in num-
ber, are three miles east of Dover Pier, on the high chalk-cliffs
overlooking the Strait of Dover, from which can be seen Gris-
Height of focal nez an<* otaer French lights. They are about 1,000 feet apart,
planes! the high light 372, the low one 275 feet above the sea, and form
a range or lead as a guide to clear the Goodwin Sands, one
of the greatest dangers in British waters. A general plan
of the establishment is shown in Plate I.
Engine-house. A fire-proof engine-house, a plan of which is shown in
Plate II, is placed midway between the towers, and con-
tains the magneto-electric machines, the engine-room, boiler-
room, coal-room, and two repair-shops. Near by are the
dwellings of the engineer who superintends the establish-
% ment, and those of some of the keepers, there being six at
this station.
X
nO
il
«o
ic
P|
O
EUROPEAN LIGHT-HOUSE SYSTEMS. 67
The electric current is generated by means of large mag- Magneto-eiec-
, trie machines.
neto-electric machines, two of which are provided for each
light, though habitually in clear weather but one machine
is used for each. These machines are driven by means
belting connected with a steam-engine, a duplicate of which
is kepi for use in case of accident or repairs. The boilers,
which are of the ordinary locomotive class, are also in du-
plicate. About 56 pounds of coke per hour are consumed coke used.
during the night 5 during the day the fijes are banked.
One of these electric machines is of French manufacture. Machines of
having been made by the Compagnie V Alliance of Paris. The giisn manafac-
others are English-made machines of Professor Holines'stl~
patent, and are considered by the Elder Brethren to be su-
perior, though the French appeared to be the simpler in con-
struction and is the one shown to visitors in explaining the
operation of generating the electric current. This operation
is fully illustrated in the description, which will be found .Description
givenatLaHeve.
further on, of the magneto-electric lights at La Heve near
the mouth of the Seine.
It may be well to state here, however, that each machine Helices,
is composed of ninety- six helices mounted upon six gun-
metal wheels, each having sixteen helices.
Between these wheels are placed the magnets, eight in Magnets.
each division, forty of which are composed of six layers or
leaves riveted together, and sixteen (the end ones) similarly
constructed but having only three leaves or layers. These
magnets, which are mounted in frames, are stationary, while
the helices revolve at the rate of four hundred revolutions
per minute.
The power absorbed by the machine alone, disregarding Power required
«.,..,. . ,. & for operating the
friction, is four indicated horse-power, and the actual power machines.
required to work one of the machines, including the friction
of engine and shafting, is six indicated horse-power.
The power of a magneto-electric machine is according to
Power of the
the gross attractive power of its magnets, each magnet hav- machines,
ing a certain lifting or attractive power, (expressed in
pounds.) In the machines at South Foreland each of the six-
plate magnets will lift 108 pounds, and each three-plate
magnet will lift 54 pounds, making the attractive power of
the magnets in one machine to be 40x108+16x54=5,184
pounds. This may be considered as expressing the power of
the machine. The proportion of the lifting power to the
actual weight of a magnet is a good indication of its value,
and, generally speaking, a magnet which will lift two and
one-half times its own weight is a good one. Each six-plate ne^flue of mag"
magnet at South Foreland has a weight of 43J pounds, and
68 EUROPEAN LIGHT-HOUSE SYSTEMS.
will lift 108 pounds. The total weight of all the magnets
in one machine is 2,088 pounds, the total attractive power
being, as stated, about 5,184 pounds.
in° madSe? Sid ^ne macnines are connected with the electric lamps placed
lamps. in the lenses of the tower by underground cables.
fe2o?nk Vyndaii The maimer of operating these machines, the arrangements
for explanations, of ^ne lenses, lamps, &c., were carefully explained to me by
Professor Tyndall, who had kindly accompanied me through
the station, and who spared no efforts to make my inspec-
tion a thorough and minute one.
Carbon points. Each lamp contains two pieces of carbon, each of which
is about 10 inches long by three-eighths of an inch square.
These are placed end to end, one above the other, and are
kept at the proper distance apart by an automatic apparatus.
The current leaps across the small space separating the
1 carbons/ and a series of sparks is formed, but so rapidly
that the eye cannot separate them, and a most brilliant
light is produced. By the automatic apparatus the carbon
pencils are moved toward each other as fast as they are
consumed, and the only danger of irregularity of the lights,
Danger from jf the machines and cables are in good order, arises from
ill© pr6S6DC6 Ot '
inrtnfIcarb1onster ^e Presence °f foreign matter in the carbons. I was told
by the keepers that the carbons in use give them trouble
in this particular, the lights being sometimes extinguished.
This is only for an instant, however, as all that is neces-
sary to relight them is to bring the carbons in contact,
after which they are replaced in their proper positions.
foi^nlnagfngthe Tne arrangements for bringing the electric light to the focus
light. of ^he iengj an(j for feeding the carbons as fast as they are
consumed, are simple and ingenious, and the duties of the
keepers, beyond watching for the occurrence of imperfec-
tions in the carbons, are very light. tThese carbons are
made from coke-dust; their rate of consumption is 34 inches
per night for each light, at a cost of one penny per -inch,
exclusive of waste and breakage.
Lenses. The lenses in use at South Foreland are of about the
same size as ordinary third-order lenses, (39 inches interior
diameter,) and were especially designed for the electric
light and this locality by Chance Brothers & Co., of Bir-
mingham.
iu5Stionarc°f Tne arc of illumination required being but little more
utilizing the than 180°, the rear light is ingeniously utilized to re-en-
force the other by means of totally reflecting prisms, and it
was observed that a much greater development was given
to the catadioptric prisms below the central belt than can
be done in the use of the large burners of the oil-light.
^ S .* ^ ^ .>. Q
a
3D
O
0
•o
5C
o
EUROPEAN LIGHT-HOUSE SYSTEMS. 69
Both lights- are fixed, and illumine somewhat more than Description of
half the horizon. In both the portion of light which would tus!°a
otherwise be wasted landward is led round by subsidiary
apparatus to intensify the illuminated arc ; but the low
light presented the peculiarity that it was desired to light
the sea brightly from the horizon to 300 yards from the base
of the tower, and as the height of the focal plane is 290
feet above the sea, this requires that a portion of the light
should dip below the horizontal plane no less than 17° 23' 32",
while the major portion should go to the sea-horizon. This
requirement was met in the following manner: The light Main appara-
frorn both the top and bottom systems of reflecting prisms u
was directed wholly to the horizon, while the central
refracting portion of the cupola was specially arranged to
give tlie required dip. The latter consists of sixteen re-
fracting segments, eight above and eight below the focal
plane, there being no central refracting belt as is usually
the case. These refracting segments are so arranged that
the intensity of the light viewed from the point distant
300 yards, or from the horizon, is sensibly the same ; also,
that no portion of the sea shall depend for its illumination
on one prism only, as otherwise that point might be placed
in total darkness, owing to a lantern-bar or other obstacle
intercepting the light.
The arrangement adopted for using the light which would subsidiary ap-
otherwise be wasted toward the land is symmetrical about Paratus-
the middle line of the apparatus, each half consisting of a
portion of a holophote, and of a frame of six vertical prisms.
The former condenses the light of the spark into a beam. of
horizontal parallel rays, which pass to the side of the appa-
ratus and are there distributed over half the illuminated
arc by the vertical prisms. The rays emerging from these
prisms do not pass through a single focus as in lights pre-
viously constructed on the azimuthal condensing plan, but
each prism has a special focus so situated that the light is
equally distributed over the arc illuminated. Probably the
plan of a common focus was adopted in some earlier cases
as simpler for calculation, and also in order to facilitate the
examination of the apparatus for adjustment, but the exam-
ination can be conducted with equal accuracy with special
foci, and no trouble should be spared to render such an ap-
paratus as perfect as possible. The outer prism of the set
is of a special and difficult construction, required because
the arc it has to illumine is situated at so great an angle
from the direction of the rays it receives. Prisms of a sim-
ilar construction had been previously suggested by Mr.
70 EUROPEAN LIGHT-HOUSE SYSTEMS.
Thomas Stevenson, engineer of the Scottish lights, and have
been used by Mr. James Chance in. several other instances.
In cases like the South Foreland, many plans for attaining
the end in view suggested themselves. It might be pro-
posed that some arrangement similar to the subsidiary one
at Souter Point (which will be described further on) should
be used. Such an arrangement would be unsuitable in the
case of South Foreland, for various reasons, among which
may be mentioned that the light would pass through three
optical agents instead of two. At Souter Point, the light
being revolving, the only feasible plan was to take the spare
light downward through the pedestal. Again, the central
cupola might have been continued entirely round the spark
and the spare light from the land-side of the cupola reflected
seaward by large vertical prisms. This plan was rejected
on account of its being unnecessarily expensive, and for
other reasons. The advantages of these and other plans
were considered by Mr. Chance before he adopted the ar-
rangement shown on the drawing.
Moderator- To supply any contingency necessitating its use a u mod-
lamp for use in _, __ , , _
case of accident, erator" oil-lamp is placed under the electric lamp and can
be quickly substituted for it. This lens is shown in eleva-
tion and plan in Plate III, in which a and a' show the elec-
tric lamp in position and withdrawn for removing the car-
bon pencils ; b ft, the carbon pencils ,• c c, the electric wires ;
d, the bed-plate ; e^ the burner of the oil-lamp ; /, the tele-
scopic supply and overflow pipes for the oil ; #, the oil-lamp ;
7t, elevation of one of the half-holophotes ; li' h', the two half-
holophotes in plan ; i i, %' i', vertical condensing prisms.
In substituting the oil for the electric light, the bed-plate
d is removed and the oil-burner e is run up to the focus by
Power of eiec- means of a rack and pinion. The power of the uii condensed
beam from each of the electric lights at South Foreland, i. e.
of the naked light without the condensation of the rays
produced by the lenses, is equal to the combined light of
2,000 candles, Avhile the corresponding power of the four-
wick sea-coast light-house oil-light is 328 candles. Estimat-
ing the power of the condensed beam from the South Fore-
land lenses as ninety times the power of the naked light,
(which is the result of Mr. Chance's calculation of the con-
densing-power of the South Foreland lenses,) we have for
the power of the beams from each of the electric lights at
South Foreland, 180,000 candles !
observations at I was shown the method of lighting the electric lamp,
night ft er ^^ .^ ^e evening observed the two lights from Dover Pier.
While the upper light was decidedly the superior, the lower
SOUTH FORELAND LIGHTHOUSES.
ELECTRIC LIGHTS.
PLATE ill
DETAILS
or
LANTERN AND LENS
EUROPEAN LIGHT-HOUSE SYSTEMS. 71
waxing and waning very perceptibly, which was caused, as
Mr. Douglass informed me, by some imperfection in the ma-'
chiuery, both of them surpassed anything I had ever seen,
and I could not convince myself that they were three miles
off. Even at this distance, the shadows of objects on the
pier were very distinct.
The towers supporting these lights are not high, (their
site being an elevated one,) and they are attached to keep-
ers' dwellings. The buildings are all constructed in the Buildings,
most substantial manner, and each dwelling is sufficient for
the accommodation of two keepers and their families, with
room for the supernumeraries who are kept at the station
for instruction. The steam-engineer (the principal official of Machines man
the establishment) and the principal light-keepers are com- SSgmeer 8 Tnli
petent to manage the engine and magneto-electric machines, 11™C1]
and they attend to this duty in turn. No laborers or fire-
men are employed. The dwellings at this station, as at all
the stations I visited on the English coast, were kept ex-
tremely neat. Rooms for accommodation of any visiting coj™™dsation aoi
officer of the Trinity House are fitted up in the dwelling ^J^J House
attached to the engine-house, and everything is provided
for his comfort, even to a full set of table-furniture.
Attached to the central station (the engine-house) are the store-rooms.
different store-rooms for the supplies, which inplude lubri-
cating and colza oils, the latter for use in the lenses in case
of failure of the electric light or of other accident ; but I
believe it Ips rarely if ever been needed. Some of the oil-
butts are of tin, the others of galvanized sheet-iron. ou-butts.
The colza (rapeseed) oil is of a pale sherry-color, very coiza-oii.
clear and limpid, with a strong and peculiar vegetable odor.
In all the houses the steps and stairs, as well as the
paving of all the halls and corridors, were of stone, rubbed
once a week with Bath-stone, which produces a color like
that given by a wash of hydraulic cement.
In the towers, and also at the engine-house, speaking-
tubes are arranged to communicate from . one to the other, Speaking-
and for the purpose of calling relief. I found such tubes at
all the stations I visited. Each keeper's watch is four hours.
Both watch-rooms and lanterns at South Foreland are watch-rooms
considerably larger and more commodious than our own. Serf lanterns'
At each dwelling is an earth-closet, placed in an out-
building, in which, instead of earth, the ashes produced at
the station are used, and I was informed that the use of
earth-closets at light-stations is universal, and gives entire
satisfaction.
72 EUROPEAN LIGHT-HOUSE SYSTEMS.
Fire, means for Means for extinguishing accidental fires are provided by
extinguishing. ^ie engjne which drives the magneto-electric machines.
The pumps are connected by pipes to each of the towers and
dwellings, the water being drawn through the chalk, from
a well at a depth of 200 feet, during high tide in the Strait
of Dover, when the water backs up into the well. Reser-
voirs are provided for use at low water.
Meteorological Two keepers are designated for each tower, who, in addi-
tion to their other duties, make daily observations with the
barometer and with wet and dry bulb thermometers, keep-
ing memoranda for the use of some department of the gov-
The keepers, ernmeut. The two principals, who are assistants to the en-
gineer, I found to be very intelligent men who seemed
thoroughly to understand the magneto-electric machines,
and who gave me a very accurate account of their opera-
tion. One of them was by trade a watch-maker, and the
other a stone-mason. The latter told me, with evident
pride, that he had laid all the stone at the Bishop Rock,
near the Scilly Islands, one of the most exposed stations in
the English service, and had been for some years the prin-
cipal keeper of that light, a position he was obliged to re-
sign, the close confinement affecting his health. Each ot
these men had been more than fifteen years in the service.
Cost of mainte- The annual cost of maintenance of a si'ngle electric English
nance of light. light is about £800) (or $4,000,) about double that of a first-
order single oil-light station, while the light produced by
the former is between six and seven times tbat$)f the most
powerful lens with the four-wick Douglass oil-burner.
cost of substi- The approximate cost of substituting at a double-light
iightgappar£^ station,the magneto-electric lights as used at South Foreland
&c.,foi £or ^je oil-lights commonly used is as follows :
Building works £7, 360 $36, 800
Lantern and dioptric apparatus 3, 088 15, 440
Electric-apparatus 5, 356 26, 780
Miscellaneous 650 3,250
Total ....£16,454 $82,270
I am indebted for my detailed description of the excel-
lent optical apparatus at South Foreland to the manufac-
turers, Messrs. Chance, Brothers & Co., of Birmingham.
THE ROMAN PHAROS IN DOVER CASTLE.
visit to Dover Through the kindness of Colonel Collinson, of the Royal
Castle. Engineers, I had an opportunity of visiting the castle at
Dover, and of attending a review of the three regiments of
Kent County militia, and of the garrison of three regi-
EUROPEAN LIGHT-HOUSE SYSTEMS. 73
inents of regular troops. Colonel Collinson showed ine
many objects of great interest — the grand old castle, from
which were distinctly visible the coasts of France, the tow-
ers of the cathedral of Boulogne, and the light-house at Calais,
on the other side of the Channel ; the rooms occupied by
Charles I and by Queen Elizabeth ; the church of Saint Mary,
Within the Castle, founded A. D. 161,* and the modern exte-
rior forts ; but nothing was more interesting to me, consid-
ering the nature of my mission to Europe, than the old
pharos within the castle walls, the present condition of
which is represented in Eig. 1.
Fig. 1.
Roman pharos in Dover Castle.
The antiquity of this light-house, which has not proba-
bly been used as such since the Conquest, no doubt ex-
ceeds that of any light-house in Great Britain, and it is
supposed to have been built in the reign of the Emperor
Claudius, about A. D. 44.*
Upon it burned for many centuries those great fires of
wood and coal formerly maintained on several towers still
standing on the coasts of Great Britain. These earliest
guides to mariners at length gave way to reflectors 5 they,
in their turn, being replaced in the year 1819 by that great Date of inven-
triumph of scientific skill, the Eresnel lens. 8y8ntemheFre8nel
The pharos, like its sister light-house, the Tour d'Ordre construction of
at Boulogne, is built of brick, in color and shape like those tbe pharos-
in the Eoman structures found elsewhere in Great Britain ; Description of
they are of a light-red color, about 14 inches long, and not theEomanbrick8-
more than an inch and a half thick. This latter dimension
* Hasted's History of Kent.
74 EUROPEAN LIGHT-HOUSE SYSTEMS.
is but little more than the thickness of the joints, which are
filled with a mortar composed of lime and finely-powdered
Eoman brick. The preservation of this famous relic of the
.Romans in England is doubtless due to the fact that some
centuries ago the tower was turned into a belfry for the
church of Saint Mary, and was surrounded by walls of stone.
These are now nearly destroyed by time, and the old Roman
work is again exposed.
While the Trinity House steam-yacht Vestal, in which I
was to take my first cruise among the English lights, was
fitting out for her annual voyage to the northeast coast
of England, I made frequent visits to the Trinity House,
visits to Trin- where I was always cordially welcomed, and thus I acquired
much information regarding the English light-house sys-
tem.
Kindness re- I received much kindness in many ways from Sir Fred-
cewecl from Sir
Frederick Ar- erick Arrow, and on the 21st of May accompanied him to a
dinner at the Mansion House, to which, through his good
Dinner at the offices, I had the honor to be invited by the Lord Mayor and
Lady Mayoress, by whom it was given in honor of the re-
turn of the Master of Trinity House, the Duke of Edin-
burgh. About three hundred guests were present, and it
was a highly enjoyable and interesting occasion.
In his response to a toast to the Trinity House, His High-
spoke of the gratitude of the corporation for the serv-
- ices rendered Sir Frederick Arrow and Captain Webb of the
Spta^n°webbElder Brethren during their stay in this country, (to which
Smites'16 Uni ^ nave Before referred.) and commissioned me to convey his
thanks to my associates of the Light-House Board of the
United States. While the services referred to were insignifi-
cant as compared with those rendered to me while in England,
I was much gratified by the highly complimentary terms in
which he mentioned our country, and particularly our light-
house establishment.
interview with While in London at this time Captain Doty, patentee of a
captain Doty. blirner for light-house illumination, addressed me a note
The Doty lamp, requesting an interview, which request I complied with, and
he showed me his lamp, which has been patented in several
countries, including the United States. It combines the
outer " cone " or "jacket," the central u button " and adjust-
able gallery, but has not the conical " tips" peculiar to the
tamSoty that fhe Douglass lamp, which also comprises the above improve-
Captain Doty claims that the Douglass or Trinity
pategnetmeiltofhi8 House lamp is an infringement of his patent, and the ques-
EUROPEAN LIGHT-HOUSE SYSTEMS. 75
tion has been before the courts, with what results I am not
fully informed, but, as I found in my subsequent inspection,
the English are rapidly changing their light-house lamps ne^n^ 8us.JDg
for those of the Douglass pattern, and their illuininant from mineral™!!?
colza to mineral oil.
Both the Doty and the Douglass lamp are especially Lamps adapted
designed for burning the latter, though they are equally10
adapted to the use of vegetable and animal oils.
Captain Doty claims, among other things, to have first sug- ^rtj^otaims
gested the great economy in the use of mineral oil, and that
the invention of his lamp made its use practicable in light-
house illumination. He stated that the French government
had issued a general order to change all the lights on the
coast of- France from colza to mineral oil ; that the Scotch
were rapidly introducing such oil for use in their light-
houses, and that his lamp had been adopted by France,
Scotland, and Sweden. Judging from my observations at opinion regard-
the trial, (which, however, was not comparative,) I believe j2np.the
Captain Doty's lamp to be an excellent one. Of his claim
to priority of invention I was not sufficiently informed to
judge $ but, from what I afterward learned in Paris from
M. Lepaute, who showed me the lamp invented by his
father in 1845, I am inclined to doubt if such claim can be Doubt as to
sustained, though I do not question the fact that Captain
Doty is entitled to much credit for having directed attention ot in™ntion.
to the advantages to be gained by the adoption of mineral
oil for light-houses.
One evening, after dining with Professor Tyndall at his observation of
club, I went with him to observe, from the terrace on which
stands the Duke of York's column, the competitive gas and
electric lights on Westminster clock-tower. The electric
light I have already described in my account of the South
Foreland light-station ; the gas-light will be fully de-
scribed in my treatment of the subject of Irish light-houses.
It may be well, however, to state here that in the experi- Wignara burner.
mental gas-light on Westminster clock-tower three Wigham
burners (each composed of 108 jets, but so arranged as to
burn 28, 48, 68, 88, or 108 jets as desired) were placed one
above another, at a distance of three feet from center to
center. Before the lower one was a refracting belt of a first- bu?ieprssitl°n °f
order dioptric apparatus for a fixed light ; before the upper
two burners were placed two refracting panels of a first-
order apparatus for revolving light, each panel being for an
arc of 45°. These panels were arranged for rotating before lo
the flame and producing in combination with the
7G EUROPEAN LIGHT-HOUSE SYSTEMS.
Brilliancy of belt, n fixed light varied by flashes. Both of these lights
were magnificently bright, but their nearness to our place
of observation was unfavorable to a comparative test, and
Elongated ap- caused the gas-light to appear vertically elongated, an effect
gSSigEt. oi be which my subsequent observations of the gas-light in actual
use in light-houses on the coast of Ireland and east coast of
England convinced me was not a necessary feature of the
e?uiiarsht ^"if svstem- ^ne reddish tinge which prevailed in the gas much
more than in the electric light would probably enable it to
more successfully penetrate fog.
^r* -^ou^ass found the power of this gas-light, burning
108 jets, the beam being uncondensed by lenticular appa-
ratus, to be equal to that of 1,199 candles when consuming
300 feet of cannel-coal gas per hour of the illuminating value
of 25 candles.
TRINITY HOUSE DEPOT AT BLACKWALL.
visit to depot. On the llth of June I went by rail to visit the principal
depot of the Trinity House at Black wall, on the Lower
Thames. This depot is much the same as our own at Staten
Island, New York Harbor, but at the former are repaired
Light-ships re- the numerous light-ships employed on the coast above and
below the mouth of the Thames, while our light-ships are
repaired at private yards,
Grounds. The grounds are rather limited in extent, and some of the
buildings are old and inconvenient, but facilities for all
kinds of work and for storage are as good as can be ob-
tained until the additional area which is desired can be pur-
chased.
Lamp-shop. The lamp-shop is very complete in its appointments, and
a large number of men are employed there. Many of them
are constantly engaged upon the manufacture and repair
of the catoptric apparatus for light-ships, of which the
English have a great number.
Reflectors stiii Jn many of the light-houses reflectors are still in use, being
considered better than lenses for some localities, especially
for range or u leading" lights.
Light-ship ap- The apparatus for light-ships is hung, as in our own service,
upon a universal joint, and an ingenious improvement has
been recently adopted, by which the reflector is adjusted by
passing the shaft of the gimbal through slots which allow
it to be moved backward or forward, and the face of the
reflector maintained in a vertical position.
Douglass lamp. In the new Douglass lamp, which is being rapidly sup-
plied to all English light-houses, the light may be increased
s
o
c
0)
n
OQ
3D
n
EUROPEAN LIGHT-HOUSE SYSTEMS.
77
1
as desired in thick and foggy weather, being in this regard
similar in effect to the electric and gas lights, although it is
not possible to make the proportionate increase so great
with oil-lrght as with those just mentioned.
These lamps are of different orders. Among those I saw Six-wick lamp,
at Blackwall was the six-wick lamp for mineral or colza oil,
(in which mineral oil was to be used,) designed to be placed
in one of the towers at Haisborough, on the east coast of
England, for experimental comparison with the gas-light,
which will receive mention when I come to describe that
station. •
This lamp is called by Mr. Douglass the " lamp of single Description.
and double power," from its capacity for increasing or
diminishing the light to suit the state of the atmosphere.
For example, in the case of the six- wick burner, shown in
Plate IV, the ordinary fair-weather light is produced by the
flame from the outer three wicks only, but, as the weather
becomes thick or foggy, the inner three may be successively
lighted, increasing the power of the flame from 342 to 722
candles — more than double its fair-weather power.
These lamps burn either animal, vegetable, or mineral
oil. The burner of one for six wicks is shown in Plate IV,
in which figures A and B are elevations showing the ad-
justment for burning mineral and colza oils respectively,
and figure 0 is a section of the latter ; a is the chimney-
holder ; 1) b the chimney ; c the exterior deflector ; d the
outer wick-case ; e the inner cases ; /the central air-space ;
(/the interior deflector ; A' and A" plan and section of in-
terior deflector for mineral-oil ; B'and B"the same for colza-
oil ; D the central button, and E an enlarged view of the
burner-tips.
In burning mineral oil the wicks are raised about one- Use of mineral
sixteenth of an inch above the tips of the burners, and the
exterior deflector is kept in the position shown at A in
Plate IV.
In burning colza the wicks are raised about five-six-
teenths of an inch above the tips of the burners. The oil
overflows as in our lamps, and the exterior deflector is
placed as shown at B, Plate IV.
About one and one-fourth inches below the tops of the wick-
cases are small holes, kept closed by caoutchouc valves
when colza is used, but when mineral oil is burned the
holes are opened and the oil is maintained at that height.
Both the exterior and interior deflectors are readily re- flc^t™sVal °f de"
moved for the purpose of trimming the wicks.
The "buttons" and "tips" are the same for all sizes ofButton8amltiP5r
.
78 EUROPEAN LIGHT-HOUSE SYSTEMS.
lamps, their number corresponding to the order of the lamp,
i. e.j the "tip" and "button" of a one- wick lamp is appli-
cable to the inner wick-case of a two, three, four, five, or
six wick lamp, and a tip of any specified number will fit the
corresponding wick-case of any order of lamp.
zone of maxi- Mr. 1 ouglass states that a notable feature in the flames
mum intensity.
of the improved lamp is the increased power of the beam in
the direction of the sea-horizon over that from an old one
of the same initial power, such increase being due to the
narrow zone of maximum intensity found in the flame of
the new burner, and which is fully utilized for tbe longest
range by the refracting portions of dioptric apparatus. In
the old flames the zone of maximum intensity does exist,
but the difference in power between it and the portions of
the flame of minimum intensity is not great.
Adoption of This level of maximum intensity, shown at h Ti in Plate
muVmLtefnsTtyX1"IV, is now being adopted by the Trinity House for the sea-
horizon focus of the refractors of dioptric apparatus and its
height above the tips of the burners in the several lamps
is as follows :
Millimeters.
Height above Burner of one wick 13
burned c the B timer of t wo wicks 14
Burner of three wicks 15
Burner of four wicks 16
Burner of five wicks . > - 17. 5
Burner of six wicks 19
Gain to light at With these adjustments of the foci some light is neces-
the zone of max- . , , -, . , . -,
irnum intensity, sarily cut off from the lower catadioptric prisms by the
u exterior deflector," but the increase of light from the re-
.fractor is very great, it having been found that the power
of the light sent to the sea-horizon or maximum range is
from 25 to 30 per cent, more than can be obtained from one
of the old flames ; that is to say, by taking two flames, one
old and one new, of the same total initial candle-power as
measured by the photometer, the beam of maximum in-
tensity in the direction of the sea-horizon from a dioptric
apparatus with the new flame in focus will be 25 to 30 per
cent, greater than with the old flame.
Gas-burner. I was shown a new kind of gas-burner, an invention of
Mr. Douglass. The top is perforated with a circle of very
small holes, and this is combined with a perforated button
similar to that used for the oil-lamp for light-houses. Out-
side is placed the adjustable jacket or cone, and the ad-
justable chimney is also used.
EUROPEAN LIGHT-HOUSE SYSTEMS.
79
The light from this gas-burner, which is shown in Fig.
2, was not, in the experiments at
Fijr. 2.
Douglass Gas-burner.
BlackwaU, equal to that from either
colza or mineral oil, on account of the
inferior quality of the gas at that
place, but I was told that it was a
marked improvement over the com-
mon gas-burner.
Mr. Douglass told me that the power Actual power of
of this Argand gas-burner when burn- £as-burcer-
ing London gas of sixteen candles is
about the same as that of the Argand
oil- burner, viz, twenty- three candles,
and the consumption of gas is about
30 per cent, less than the best burner
before used in England.
The buttons for the gas-burner when Buttong when
made of brass last but a little while, made of brass
soon destroyed.
They have been made of platinum,
but this is expensive, and when I last
heard from Mr. Douglass he was ex-
perimenting with buttons made of
lava, which promised good results.
He states that there is no difficulty in
producing a gas-burner of the size of
the six- wick oil-lamp, or even larger, «ze of a six-wick
' lamp easily pro-
on the same principle. One of five
rings of flame has been tried, and the
illuminating power is precisely the
same as with the small burners pro
rata of gas consumed.
The following extract from a letter
Lava proposed.
Gas-burner the
of recent date, written me by Mr. Douglass, may prove of Extract from
, letter concerning
importance to us in the future, and 1 here place it on record : a recently. pat-
. , , . , en ted gas-burner.
" I have just found that a patent has been taken out by
Mr. Silber (the patentee of a mineral-oil burner) for a gas-
burner nearly identical with my own, but, fortunately, the
date of the patent is nearly a month after I reported to the
Trinity House the results of experiments made with burners
I had made for some new light-houses. It is probably
important that you know this, as it is not unlikely that a
patent has been taken out for the burner in America. I
will send you a copy of the paper as soon as it is published."
As I have before remarked, the light-house establishments increase of
_ T, powerof light and
of Europe have greatly increased the power of their lights decrease of ex-
penses.
so
EUROPEAN LIGHT-HOUSE SYSTEMS.
with a concurrent decrease of expense, changes which have
been produced by the introduction of mineral-oil and the
improvements in burners.
Report of Mr. I can best , illustrate this important subject by quoting-
one of the earliest reports in regard to this matter made by
Mr. Douglass to the Trinity House, dated 30th of March,
1871, which I find in a " Eeturn to an Order of the House of
Commons dated 26th of June, 1870, for a copy of < Corre-
spondence between the general light-house authorities and
the Board of Trade, relative to proposals to substitute min-
eral oils for colza oil in light-houses.'"
" TRINITY HOUSE, March 30, 1871.
u Eeferring to the various and lengthened experiments
which have been made at this House for the purpose of de-
termining the suitability of paraffine and petroleum oils for
the illumination of light-houses, and the most efficient lamp
for consuming these mineral oils, I now beg to submit the
following report :
samples of oils " For the purpose of ascertaining the relative merits of
paraffine and petroleum oils, a sample of the best burning
paraffine was obtained from Messrs. Young & Co., and sam-
ples of the best burning petroleum-oil were obtained from two
respectable manufacturers of that article. The samples were
as follows, viz :
C o m p a rative
table.
Specific
gravity.
Flashing-
point.
Net price per gallon.
Messrs. Young & Co.'s paraffine-oil
Trinidad Petroleum Company's petro-
leum-oil.
.811
.820
136°
130°
Is. 6d.
Exact price not stated ;
said to be about 2s.
Carless, Capel & Co.'s petroleum-oil
.796
116°
2s.
Kesult of trial
in ordinary lamp.
Colza used.
First e x pe r i
meats.
"It was found that the three samples, when consumed in
an ordinary single-wick paraffine lamp, gave nearly the
same photogenic results ; and, being fairly equal as to
safety, the paraffine of Messrs. Young appeared, on the
score of economy, to be the most desirable material for the
purpose ; it was therefore decided to carry out all further
experiments with this oil.
"The colza-oil used in the experiment was taken from the
corporation's stock at Black wall ; it had a specific gravity
of .915, and was of excellent quality for illuminating pur-
poses.
"The first experiments were made by consuming the oil
in the ordinary Trinity House Argand single- wick, and
EUROPEAN LIGHT-HOUSE SYSTEMS.
81
first-order four- wick lamps for colza-oil. No alteration of the
lamps was found to be necessary to effect this, but the best
result was found to be obtained when the surface of the oil
in the wick-case was lowered somewhat below tbe level of
the tip of the burners. A good, bright, steady flame was
maintained in each lamp, and the following are the results:
" In recording these results, the photometric value of each
light is expressed in English units or standard sperm can-
dles consuming 120 grains per hour. The value of colza-oil value of colza,
is the contract-price for this article for the current year,
(3s. 4:d. [S3 cents] per gallon,) and the value of paraffine is
the contract-price of Messrs. Young for the current year, (Is. affine-
6d. [37 J cents] per gallon:)
Argand turner— Paraffine and colza oils.
Value of par-
Lamp consuming
paraffine.
Lamp consuming
colza-oil.
Illuminating power of tho light
8. 4 units
13. 9 units.
. 0115 gallon. Result with tho
. 00083 gallon. Argand burner.
. 460rf.
. 033d.
Consumption of oil per burner per hour
. 0130 gallon
.00123 gallon
lS6d
Consumption of oil per unit of light per hour
Cost of light per burner per hour
Cost of light per unit per hour
.022c?
First-order four-wick burner — Paraffine and colza oil.
Lamp consuming
paraffine.
Lamp consuming
colza-oil.
Illuminating power of light
209. 7 units . . .
269. 0 units.
Consumption of oil per burner per hour
Consumption of oil per unit of light per hour
Cost of ) ight per burner per hour
Cost of light per unit per hour
.20760 gallon....
.00099 gallon....
3. 13d
.QlSd
. 25824 gallon.
. 00096 gallon.
10. 33d.
. 038d.
Eesult with
four wick burner.
" In these experiments the lamps were kept burning for
six hours without any trimming of the wicks ; the illumi-
nating power of the lights was determined every hour by a
Bunsen's photometer, and the powers given are a mean of
those powers.
"The first lamp improved was the single-wick or Ar- improvement
gaud ; the alterations effected to this lamp were as follows,111
viz : The tips of the wick-case were closed so as to fit more
closely to the wick, and beveled for the purpose of admit-
ting the ascending currents of air freely to the lower part
of the flame ; a perforated button was introduced at the
center of the burner ; the wick-case was lengthened for the
purpose of economizing the consumption of wick, and an
alteration was made in the form of the glass chimney. The
results of a six hours' trial with this improved burner,
S. Ex. 54 6
82 EUROPEAN LIGHT-HOUSE SYSTEMS.
which has now been in use at the Milford leading-lights
for the last three months with good practical results, are as
follows :
Improved Argand burner.
Result with im-
proved Argand
burner.
Lamp consum-
ing paraffine.
Lamp consum-
ing colza-oil.
Illuminating power of the light
20. 6 units.
13 9 units.
Consumption of oil per burner per hour
Consumption of oil per unit of light per hour . . .
. 0109 gallon.
. 00053 gallon.
IQGd
. 0115 gallon.
. 00083 gallon.
461d
Cost of light per unit per hour
: O09d.
033d
" The above experiments with this lamp, as now improved,
show the comparative cost of light produced by colza-oil and
paraffiue to be as 33 to 9, 11 to 3, or 55 to 15. (See tables.)
inImfPoTre-wick " The experiments with the Argand burner, which had been
burner. so successful, were followed by similar experiments with the
first-order or four- wick burner. The alterations effected to
this burner were as follows, viz : The tips of the wick-cases
were closed so as to fit closely to the cotton wicks, and were
beveled in the same manner as the Argand lamp, for the
purpose of admitting the ascending currents of air freely to
the lower part of each ring of flame ; and the wick-cases
were considerably lengthened for the purpose of economiz-
ing the consumption of cotton-wick. Glass chimneys of
various forms were tried, but no better result has been ob-
tained than with the chimney usually used with the four-
wick burner for consuming colza-oil. After a series of trials
it was found that the best photogenic result was obtained
with the surface of the oil in the wick-case three inches
below the tips of the burner ; it was therefore necessary to
keep the oil uniformly at this level during the burning of
the lamp, which was done by placing at a short distance
from and level with the burner one of the flow-regulating
cisterns formerly used for light-house lamps, which receives
from an upper reservoir a supply of oil, and maintains the
supply to the burner at the required level by a self-acting
ball-cock. I have devised another and, in my opinion, a
more perfect arrangement for regulating the flow of oil in
these lamps, which has been tried with perfect success.
oil-regulator. " I be^ to submit herewith drawings of the improved Ar-
gand and first-order four-wick lamps, on the latter of which
is the self-acting regulator. This regulator consists of a
stand-pipe placed at the side of the burner ; the top of this
pipe, which is open, is at the level at which the oil is in-
tended to flow in the wick-cases j a portion of the supply of
oil from a reservoir placed above the level of the burner, or
EUROPEAN LIGHT-HOUSE SYSTEMS. 83
from the cylinder of a pressure lamp, flows up the stand-
pipe and overflows at the top, descending by another pipe
surrounding the stand-pipe to a cistern below the burner.
A glass thimble is screwed on to the top of the regulator,
through which the state of the flow can be observed. The
necessary adjustments of supply are made from time to time
by the ordinary regulating- valve placed in the supply-pipe*
below the burner. The tops of the inner and outer tubes of
the stand-pipe are rendered telescopic by a piece of pipe
fitted to and sliding on them externally ; by means of these
sliding pieces the flow of the lamp can be altered at any
time so as immediately to adapt it for burning any descrip-
tions of hydrocarbon. As the invention appears to me to
be of importance for regulating the flow of all lamps used
for burning mineral oils, I have had it provisionally pro-
tected.
"As it is found to be necessary in burning paraffine that
its level in the wick-case be considerably below the top of
the burner, it may reasonably be expected that the tips of
the burners will be destroyed by the heat of the flame much
sooner than with burners consuming colza-oil, where the
latter is constantly overflowing the burners and keeping
them cool. I have provided for this increased destruction of
burners by fitting each with removable tips, as shown on Removable tips.
the accompanying drawings. With this arrangement, and
by keeping a supply of spare tips at each station, the tips
of the burners may be renewed at any moment by the light-
keeper in charge, thereby avoiding the necessity for return-
ing the burner to the workshops for repairs.
" The following are the mean results of several six-hour
experiments .
Improved first-order four-wick burner.
Lamp consuming
paraffine.
"TEST-
Illuminating power of lifht
280 units
269 units.
Consumption of oil per burner per hour
Consumption of oil per unit of light per hour
.23240 gallon....
.00063 gallon....
3 81d
. 25824 gallon.
. 00096 gallon.
9 02d
Cost of lio'ht per unit per hour
033d
lamp.
" The above experiments with this lamp, as now improved, cost <J?c<5za ami
show the comparative cost of light produced by colza-oil pa
and paraffine when consumed in a first-order burner to be as
38 to 15. From these results it will be observed that the
superiority in illuminating power of the paraffine over the
84
EUROPEAN LIGHT-HOUSE SYSTEMS.
colza oil is much greater when consumed in the Argand
burner than when consumed in the large four- wick burner ;
consequently the contrast between the cost of light pro-
duced by the two oils is greater when the oils are consumed
in the Argand burner than when consumed in the four- wick
burner.
* " Further experiments were made for ascertaining the
relative illuminating power of the paraffine and colza lamps
during the time required at a light-house on the longest
winter night. Each lamp was kept burning for sixteen
hours without any trimming of the wicks, and the following
are the photometric results of several experiments :
IMPROVED ARGAXD BURNER.
IMPROVED FIRST-ORDER FOUR-WICK
BURNER.
Hours.
Paraffine lamp.
Colza lamp.
Hours.
Paraffino lamp.
Colza lamp.
1
Units.
20.6
20.6
20.6
20.6
20.4
20.4
20.0
20.0
19.6
19.6
19.2
19.0
18.7
18.6
18.5
18.5
Units.
13.9
13.9
13.9
13.9
13.6
13.3
12.7
12.7
12.7
12.7
12.7
12.3
12.1
12.0
11.9
11.8
12.8
1
Units.
280
274
280
278
278
278
274
277
271
266
265
277
267
266
256
250
Units.
269
263
261
246
249
242
235
246
240
2:54
232
. 227
233
224
230
200
2
2-. . ...
3
3
4
4
5
5
6
6
7
1
8
8
9
9
10
10
11
11 ;
12
12
13
13
14
14
15
15
16
16
Mean
Mean
19.7
271
239
Deductions. " From these results it is apparent that the paraffine lamps
will burn throughout the longest winter night in this coun-
try without any trimming of the wicks, and give during
Sustained inten- this time a light of nearly uniform photometric value. At
the end of sixteen hours the illuminating power of the
Argand lamp, burning paraffine, was only 10 per cent, less,
and in the four-wick lamp only 10.7 per cent, less, than at
the commencement of the trials, while the illuminating
power of the lamps burning colza-oil gradually decreased
soon after the commencement of the trials, and at the end
of sixteen hours the illuminating power was reduced 15.1
per cent, in the Argand burner, and 25.6 per cent, in the
four- wick burner.
state of wicks. "At the termination of these trials the wicks of the par-
affiue lamps were not much fatigued ; the tips were charred
EUROPEAN LIGHT-HOUSE SYSTEMS. 85
only one-eighth of an inch in depth, and to all appearances
the lamp was fit for burning many hours longer. The wicks
of the colza-lamp were much distressed; they were charred
five-sixteenths of an inch in depth, and evidently nearly
worn out ; trimming would have been absolutely necessary
if burned for three or four hours longer.
" In conclusion, it may be generally stated as the result
of the lengthened experiments which have been made at
this House with paraffine as an illuminant for light-houses' —
" 1st. The cost of light is 72.7 per cent, less ichen produced comparative
by the Argand or single-icicle lamp, and 60.5 per cent, less
when produced in the first-order or four-wick lamp, than colza-
oil.
" 2d. The lamps burning paraffine ivill give a light of more Paraffine light
uniform illuminating power throughout the night, icithout trim- ra<
ming, than the lamps burning the colza-oil.
"3d. The lamps burning paraffine are more readily ignited ; Paraffine lamps
they burn icith greater certainty, and require less attention than ea
lamps burning colza-oil
u 4th. The lamps burning paraffine may be arranged for increase ot
increasing the poicer of the light when the state of the weather po
requires it, as is now done with the electric light and coal-gas.
" 5th. Paraffine can be stored and used at light-houses with paraffinc may
safety, provided that ordinary care is used. safety rcd wltU
" I am, &c.,
"JAS. N. DOUGLASS."
The tables given in the foregoing report showed —
1st. That light for light with a first-order lamp, the cost Cogt with first.
of the paraffine was about one-half that of the colza light. or%der lamp-
2d. Light for light with the fourth-order lamp, the cost of Cost with
paraffine teas about one-fourth that of colza. fourth-order
These results were confirmed by a comparison of the fig-
ures in the following table of results obtained by Dr. Mac- Confirmation of
adam, scientific adviser of the board of commissioners of
northern (Scottish) lights, Mr. Douglass, engineer of the
Trinity House, and Professor Tyndall, scientific adviser of
the Trinity House, by quite separate and distinct experi-
ments.
86
EUROPEAN LIGHT-HOUSE SYSTEMS.
Comparative statement of experiments for testing the values of colza andpar-
affine as illuminants for light-houses.
Dr. Macadam.
Mr. Douglass.
Dr. Tyndall.
<s
,2
o
o
©
c
1
dt
£
"o
u
<s
«
1
i
§
1
292. 93
2.134
.2226
. 00076
4.01
. 013
51.85
18.49
58.9
. 01335
. 00072
. 2402
.013
75.47
FIRST-ORDER LAMP :
Illuminating power of light expressed
in standard candles, consuming 120
grains per hour
261.3
261.3
269.
280.
4 09
284. 85
Percentage of increase of light in favor
of paraffi ue
Consumption of oil by the lamp during
one hour in imperial gallons
.2077
. 00079
8.30
.1967
. 00075
3.55
. 2582
. 00096
9.02
.2324
. 00083
3.87
.014
57.57
20.6
48 2
.1928
. 00067
7.71
.027
11.63
Consumption of oil per caudle per hour
in imperial gallons
Cost of light per hour in pence
Cost of light per candle per hour in pence
Percentage of saving in cost in favor of
paraffiue
.032
.014
56. 25
19. 83
75.02
.0125
. 00063
.218
.011
76.6
.033
13.9
FOURTH-ORDER LAMP :
Illuminating power of light expressed
in standard candles, consuming 120
grains per hour
11.33
Percentage of increase of light in favor
of paratfine ...
Consumption of oil by the lamp during
one hour in imperial fallons
.0133
00117
.532
.047
.0115
. 00083
.461
.033
.0109
. 00053
.196
.009
72. 72
.0146
. 00126
. 6132
:053
Consumption of oil per candle per hour
in imperial ""aliens
Cost of light per hour in pence ...
Cost of light per candle per hour in pence
Percentage of saving in cost in favor of
paraffino
The foregoing tables were among the earliest results of
experiments with paraffiue oil and petroleum.
^he improvements made by Mr. Douglass from time to
by ., r. Douglass. ^jme jn lamp-burners have resulted in what is apparently a
perfect light-house lamp, which can hardly be surpassed in
economy and efficiency except by the supply of pure oxy-
gen to the flame.
Details of lamp. Each of the Douglass lamps now made for the English
light-houses has —
Burner-tips. ist. A series of burner-tips so constructed that they may
be removed when burned out, instead of substituting new
burners, as is done under the old system.
These "tips," which slightly compress the wicks, give to
them a perfectly cylindrical form, and their exterior sur-
faces being slightly conical, the air from below is sent
directly into the flame without danger of forming eddies
where the gases burn imperfectly.
interior deflect- 2d. A curvilinear perforated " button," (interior deflector,)
which sends the interior current of air into the flame.
3d. An outer "cone," (exterior deflector,) by which a
second current of air is thrown into the flame at its most
advantageous zone.
4th. A space between the cone and the chimney, by
which a third or outer air-current is produced.
Exterior deflect-
or.
Outer
rent.
air-cur-
EUROPEAN LIGHT-HOUSE SYSTEMS.
87
This air-current is injected into the flame above that ad-
mitted by the " exterior deflector," and is for the purpose
of increasing combustion. A portion of this current being
drawn up along the surface of the chimney, prevents the
heat from melting or otherwise injuring the glass, in which
a milkiness resulting from disintegration sufficient to im-
pair the light, is found to be produced by long-continued heat.
Another result produced by this current is that the base
of the chimney is kept at a degree of temperature suffi-
ciently low to admit the removal of the chimney with the
naked hand, rendering the use of tongs unnecessary.
5th. An adjustable gallery by which the chimney is raised
and lowered at will, it being found that the height of the
shoulder of the chimney has a marked effect upon the flame.
6th. Yery soft and compressible wicks adopted for this
lamp only after many repeated experiments.
Each of these inventions, some of which were original
with Mr. Douglass, and some had previously been in use,
is considered of importance, but a combination of the whole-
is essential to produce the remarkable results given in the
following table deduced from the most recent experiments
of Mr. Douglass and kindly sent me by him since my re-
turn to this country :
Comparative statements showing the mean illuminating power and consumption
of oil with the old and improved light-house burners of the Corporation q,
Trinity Rouse.
Chimney ko p t
cool.
Adjustable gal-
lery.
Soft wick.
Combination of
these inventions.
Compar a t i v e
monts with Mr.
Douglass's burn-
Old concentric burners con-
suming colza.
Improved concentric burners con-
suming colza.
Number of wicks:
Full power
Half power
4
3
2
1
6
3
5. 00
722
342
76.24
36.12
.106
5.5
5
3
4.16
514
225
51.81
22.68
.101
5.0
4
2
3.32
328
178
32.12
17.43
.098
4.5
°1 93
3
2
2.49
208
146
20.17
14.16
.097
3.2
24. 55
29.86
2
1
1.65
82
51
7.87
4.80
.096
2.8
41.38
28.57
1
.82
23
2.20
.096
2.2
65.47
24.81
Mean diameter of
outer wick, (in
inches)
3.32
2G9
2.49
167
1.65
58
.82
13.9
Illuminating
power of flame in
standard sperm
candles, (or
units,) consum-
ing 120 grains
per hour :
Full power
Half power
Consumption per
burner per hour
in fluid-ounces,
128 to American
wine-gallon :
Full power
Half power . . .
Cou sumption per
unit per hour in
fluid-ounces
Mean height of
flame, (in inches).
Increased illumi-
nating power of
improved burn-
er, i>er cent
39.77
23.09
7.79
1.77
.148
3.75
.138
2.5
.134
2.0
.128
1.5
Saving in oil with
new burner for
c no h unit of
liiiht, per cent .
33.77
88 EUROPEAN LIGHT-HOUSE SYSTEMS.
Consumption of An inspection of the above table shows the consumption
of colza-oil in the new burner to be very nearly one-tenth of
unit used. an ounce for each unit of light, that unit being the light
from a standard sperm-candle consuming 120 grains per
hour, and Mr. Douglass informs me that the improved
Power of ihiht burners have raised the power of light produced from colza to
from colza with , . . .
new burner equal such a degree that this oil is now practically equal in illu-
to that of best ,. -, ,.
mineral-oil. uiinatiug power and consumption to the best mineral-oil
found in Great Britain, the latter having a specific gravity
ranging from .810 to .820, flashing above 130° Fahrenheit
tween cX and and distilling between 212° and 572° Fahrenheit, so that
6 °f the difference between mineral and colza oil for light-house
illumination is principally one of economy. In England the
Cost of colza, cost of colza-oil is about 2s. 9d. (68 cents) per imperial gal-
Of minerai-oii. Ion, that of mineral-oil of the quality abovp, stated being 1,9.
Id. (39 cents) per imperial gallon, so that in that country,
for all orders of light-house lamps, the cost of maintaining
mineral-oil sea-coast lights is about one-half that of maintaining
colza-oil lights.
substitution of For this reason, as well as because mineral-oil lamps are
mineral for colza '
oil. much more cleanly, more easily lighted, and require no trim-
ming during the night, thus making their efficiency less de-
pendent on the watchfulness of keepers, the English are
rapidly substituting mineral-oil lamps in their light-houses
for those for colza formerly used.
Price of lard-on. In the United States the average price of our illumiuant,
lard oil. of which we annually use about 100,000 gallons, is
post of mineral- 89 cents per gallon 5 the cost of mineral-oil of the quality
required by the British and French contract-specifications
is about 35 cents per gallon.
The following table gives the comparative values in stand-
ard candles of the new English Douglass and the American
light-house lamps :
6
5
4
3
2
1
English, lamps valuo in caudles
722
514
328
208
82
23
210
133
44
15.3
56
56
86
50
An examination of the foregoing tables and the facts j ust
stated shows :
1st. That by the adoption of the triple current of air burn-
ers of the English and French into light-houses, we should gain
more than 50 per cent, in the power of our lights.
2d. By the adoption of American mineral-oil instead of
the lard-oil now used in our light-houses, we should save $54,000
per annum in cost of oil.
EUROPEAN LIGHT-HOUSE SYSTEMS. 89
This is on the supposition that the American refiners will pro-
duce, if stimulated by the use of the former by the Government,
an article equal to that used in Europe for light-house illu-
mination.
3d. If it should be found that such American oils can-
not be obtained, precisely the same excellent quality of mineral-
oil ( Scotch) as is used in the liglit-houses of France and Great
Britain can be imported at a cost, including freight,* not exceed-
ing 30 cents per gallon, and the saving in this case would not be
less than $53,000 per annum in cost of oil.
Since rny return from Europe the Trinity House has kindly
sent to the Light- House Board several improved four- wick
burners, for both colza and mineral oil ; interior deflectors
for cutting off one, two, or three wicks ; one Argand lamp,
complete, for burning colza or mineral oil; and one Argand
gas-burner, as well as a supply of wicks, chimneys, &c., for
use with the lamps and burners sent.
In regard to the purchase of mineral-oil, I give below specifications
some extractsfrom the specifications which the Trinity House 01
furnishes to bidders :
u 1. The mineral-oil required to be supplied under this con- Quality,
tract is to be of the best possible quality, the greatest care
is to be taken in its preparation, and it must be as free as
possible from oil of vitriol.
" 2. If the oil be petroleum, it must have a specific gravity specific gravity
not less than .785, nor greater than .790, at 60° Fahrenheit ; ifpetl
its flashing-point not lower than 125° to 130° Fahrenheit,
and it shall distill between 212° and 482° Fahrenheit.
" 3. If the oil be paraffine, it must have a specific gravity of paraffine.
not less than .810 nor greater than .820 at 60° Fahrenheit ;
flashing above 130° Fahrenheit, and distilling between 212°
and 572° Fahrenheit.
" 4. A sample of five gallons of each of the oils proposed to samples.
be supplied is to accompany the tender ; such sample will be
tested by burning to ascertain its action on the wick, and Tests.
its specific gravity, flashing-point, and chemical composition
(to be determined by fractional distillation) being ascer-
tained, the several results shall, if approved, be considered
binding in all subsequedt deliveries of oil under this contract.
u 5. The contractor will be furnished with tinned iron cans cans furnished.
to hold the required amount of oil for each light-house;
* The contract-price of oil in England is, as stated above, Is. 6d. per
imperial gallon, or about 39 cents. The freight to New York I have
ascertained will not be over 4 cents, making its cost here of the im-
perial gallon 43 cents, or, as this is one-fifth larger than the American
wine-gallon, about 36 cents per wine-gallon.
90 EUROPEAN LIGHT-HOUSE SYSTEMS.
every can will contain about five gallons, and will weigh
net about 21 pounds. The cans will be delivered to the
contractor at the Trinity Buoy- Wharf, Black wall, in per-
fectly tight and sound condition, and the contractor must
assure himself thereof at the time of his receiving them, as
no plea of unsoundness will be admitted after acceptance,
in case of leakage or fracture.
Test when oil " 8. Samples will be drawn at pleasure from any portion of
ed> each parcel delivered, and shall be tested in accordance with
the tenor of paragraph 4. In the event of the test being
satisfactory, such parcel shall be formally received, but if
not, the contractor shall, at his own expense, remove the
whole quantity within ten days after receiving notice of re-
jection, and must immediately replace the same with another
supply, which latter shall be tested in like manner. Records
will be kept of the results in each case of testing samples."
Tests at depot. All oils are thoroughly tested twice : first by the officers
of the depot at Blackwall, and afterward in samples, by the
engineer and Elder Brethren at the Trinity House.
Processof test- The process of testing the colza-oils received from the con-
ing colza.
tractors is thus described :
waders168 from Each of the parties tendering bids sends a sample of
twenty gallons marked with a letteronly, so that, while test-
ing, the manipulator has no knowledge of whose oil is under
test. A sample of the previous year's supply is also intro-
duced with the others ; of the identity of this also the ma-
nipulator is ignorant.
Special quaii- ^ne °^s are tested with regard to the consumption ; the
ties required. effect of combustion upon the wick 5 the illuminating power
and specific gravity 5 also with regard to congelation.
Lamps used. For consumption and combustion, the samples, including
that of the previous year's supply, are tried in Argand lamps
kept burning for sixteen hours, that being considered as
about equal to the longest winter night. During this time
particular notice is taken of any diminution of the flame,
(which must be kept 1J inches high,) or any other irregularity
of combustion, and at the expiration of the time the residue
in each lamp is carefully measured to ascertain the exact
quantity consumed.
Measure of iiiu- The illuminating power of each oil is measured bv a pho-
Tninating power.
tometer, (Buusen's, used also in our service,) and the unit
is, as with us, the standard candle consuming 120 grains per
hour. The observation is taken at the full power of the
light when first lighted, and again at the end of the trial .
EUROPEAN LIGHT-HOUSE SYSTEMS.
91
The specific gravity of each oil is measured by an ole- Measure of
gravity.
ometer in the usual way.
To ascertain with regard to congelation, samples of each congelation.
oil are placed in half-pint clear glass bottles and subjected
to a temperature of 25° Fahrenheit, at \vhich temperature
they should remain fluid for sixteen hours.
A portion of the original twenty gallons supplied by the
,
firm who obtains the contract is retained, and a sample
from every cask delivered by them during the period of the
contract is comparatively tested with the original sample.
Trinity House acts as agent for the purchase of oil for the Trinity House
delivered.
Fig. 3.
agent for foreign
light-house es-
tablishments.
Storage capa-
city at the depot.
Oil-tanks.
Cocks.
light-houses of some foreign
countries and of several of
the English colonies. The
storage capacity for oil at
Black wall is about 210 tons,
(about 54,000 gallons.) The
great cast-iron tank for colza-
oil is divided into compart-
ments, and is much like our
oil-tank at Staten Island.
The oil is drawn from two
levels, and it is the universal
practice in the English light-
house service to draw from
more than one level wherever
large oil-vessels are used,
some of the 100-gallou oil-
butts, having as many as three
cocks at different heights.
The level of the oil in each
tank is shown by means of a
float attached to a chain,
which passes over a pulley at
the top, to a weight moving
upon a graduated scale on the
outside. The oil is emptied
into the tanks through pipes
leading from the floor above, Five-gallon oil-can,
and is delivered from the tanks for issue to the light-houses
into sheet-iron "drums" (cans) holding five gallons each, and Five-gallon
which are 11 inches in diameter and 15 inches in height. cans'
A recess, made by sinking the top below the sides, con-
tains the handles a a, (see Fig. 3,) and a screw-plug for
emptying.
These cans are purchased by contract, but are tinned caJ8urc h a8e of
Float to show
oil-level.
92
EUROPEAN LIGHT-HOUSE SYSTEMS.
Machine-shop.
on the inside by the workmen at the depot. They are
in size and construction admirably designed for trans-
port. Three of them can be easily carried by two men,
and they stow in the supply- vessels and boats -with little
Plan of delivery loss of space. They are also strong and durable. I think
^aa^hj^ it a better plan for delivering oil to light-houses than ours
of shipping it in barrels on the eastern coast and in
square tin cans to the Pacific coast light-houses.
^Lamp-chim- Especial attention is paid to the testing of lamp-chim-
neys, which are distributed to the light-houses from Black-
wall depot.
A gauge, &, of metal is fastened to a frame, a, (see
Fig. 4,) in which the chimney is placed, and its accuracy
Fig. 4. of shape and thickness is deter-
mined by turning it around its axis.
Those which do not fit the gauge
closely are rejected.
The machine-shop is well fitted up
with machinery, including lathes,
drilling and screw - cutting ma-
chines, and all kinds of work, ex-
cepting heavy forging and casting
of iron, are done here; even the
manufacture of the furniture used
in the light-house towers and keep-
ers7 dwellings.
Among great varieties of work
I saw constructing in the smith-
ery a lantern for a light-ship, made
entirely of iron, the sash-bars being
Chimney-gauge. of malleable cast iron.
Lampstrimmed This lantern was not intended to be lowered to the deck
Stern! m Qg for trimming the lamps, as is usual, but was designed to re-
main in its place on the mast, which is to be of hollow steel
about two feet in diameter. Small doors open from the hol-
low of the mast on to the deck, and also into the lantern
when placed in position, an inside ladder affording a means
of communication with the lantern at all times.
There is about 20 inches space between the sides of the
lantern and the reflectors, to enable the keepers to trim the
lamps, and an outside foot-rail is provided to enable them to
clean the exterior of the lantern-glass.
Question of Whether so heavy a, mast and lantern can be carried on
in all weathers is yet a matter of experiment,
Lantern for
ght-sliip.
EUROPEAN LIGHT-HOUSE SYSTEMS. 93
but there can be no doubt that facility of trimming without
lowering the lantern is much to be desired.
There was also constructing a set of machinery for a fog-
bell, the driving- weights of which were square and furnished
with rollers on the sides to avoid friction against the boxes.
Above the buoy-shed is a convenient photometric gallery
for testing lamps, oils, and lenses. It is about 80 by 12 sallery-
feet, the interior is painted black, and the sky-lights are so
arranged that all daylight can be excluded.
At Blackwall is always kept a light-ship for relief in case Relief light-
of accident to any of the numerous light-ships on the coast
near the Thames, and this is also the place of repair not
only for these vessels but for the steam-tenders.
Trinity House ceased some years ago to build iron light- ir0n light-ships
ships, on account of their fouling so rapidly and the conse- g>°r8idered illte'
quent necessity of bringing them into port once in two
years, while the wooden light-ships require to be brought in
but once in seven years. Further reasons for giving up the
use of iron light-ships are that they are cold and damp, and
when run into, sustain much more danger than the wooden
vessels.
The approximate cost of a light-ship, either of iron or cost of light-
wood, including everything, is, in England, £5,500, or about shlp'
$27,500.
The size of English light-ships is about the same as our size,
own, although the latter have much greater beam and depth
of hold, and are more rounded at the sides, which probably
enables them to ride easier and with less shock to the catop-
tric apparatus and the lantern.
Those placed in exposed situations are usually held by Moorings,
single mushroom- anchors, weighing two tons, and each
light-ship has 210 fathoms of 1 J-iuch cable.
The Seven Stones light-ship, oft' Land's End, is anchored u Anchors of the
in 42 fathoms of water and has 315 fathoms of cable attached
to her mushroom.
In addition to these moorings every light-ship has on Additional
board spare anchors and cables in readiness to be let go at anchors-
a moment's notice in case the vessel should drag her anchor,
but such an occurrence has not happened for several years.
The chain-cables used by all the vessels of the Trinity chain-cahies:
House are made with great care1. The requirements and the S"rac™enti
mode of testing are as follows :
All the cables, mooring-chains, rigging and crane chains, Quality of
and articles appertaining thereto, excepting the stay-pins
and steel pins, are manufactured from fine fibrous iron of ap-
proved quality, and must bear a tensile strain of not less than
94 EUROPEAN LIGHT-HOUSE SYSTEMS.
23 tons per square inch of original area, with a contraction
at fracture of not less than 45 percent, of the original area.
Pfisality of 8tay" The cast iron in stay-pins is of the best tough gray metal,
and must bear a cornpressive strain of not less than 52 tons per
square inch of original area, with a reduction in length of
not less than 10 per cent.
steel pms. The steel pins for retaining the joining shackle-bolt are
of the best and toughest manufacture, and must bear a
tensile strain of not less than 35 tons per square inch of
original area, with a contraction at fracture of not less than
45 per cent, of original area.
workmanship. All cables, mooring-chaius, rigging and crane-chains, and
articles appertaining thereto, are required to be of the best
possible workmanship. They are proved at a proving-ma-
chine, licensed by the Board of Trade, at the expense of the
contractor, and the proving is carried out in the presence
of the engineer or other designated officer.
Proof-strains The chains are subjected to the following proof- strains,
for testing
chains. viz : Open-link cable and moormg-chams, and close-link
rigging and crane chains are proved to 8.47 tons per square
inch of each side of the link, or 466 pounds per circular
one-eighth inch of the diameter of the iron, and stud-chains
are proved to 11.46 tons per square inch of each side of tbe
link, or 630 pounds per circular inch of the diameter of the
iron. Any links which may appear to be defective are cut
out and replaced, and the chain re-proved at the expense of
the manufacturer. If more than three links are found to
be defective in any length after proving, such length is con-
sidered liable to rejection. All forelock- shackles, connect-
ing-shackles, and spare swivels, are proved to the same
strain as the chain with which they are intended to be used.
Further tests ^n addition to the above proof, and for the purpose of
ascertaining the exact quality of the iron and welding, the
engineer selects, as he may think fit, from any lengths of
each of the sizes of chain ordered, three test-pieces, four
feet long of each size. These pieces are cut out of the
chains, and, together with a shackle of each size, also selected
by the engineer, are stamped with a Trinity House stamp,
and are sent by the contractor to such public testing-works
as may be designated by the Trinity House, to be tested
and reported on by the engineer of the Trinity House,
at the contractors expense. The quality of the iron is
ascertained by testing the iron in one link cut off each
of the pieces of chain, also the iron in each of the
shackles. The remainder of each of the four-foot lengths
of chain is then tested to ascertain the quality of the weld-
ing, when the ultimate breaking-stress must not be less
EUROPEAN LIGHT-HOUSE SYSTEMS.
95
than 16 tons per square inch of each side of the link, or
880 pounds per circular one-eighth inch of the diameter of
the iron. In the event of these tests proving satisfactory,
the lengths of chain from which the test-pieces were taken
are to be made good by the contractor, and the lengths re-
proved at his expense. In the event of any portion of the
material or welding, when tested, proving inferior in quality
to that specified, the chains and shackles are rejected, and
the above tests are repeated at the expense of the con-
tractor on other pieces of chains and shackles selected by
the engineer in the same manner from other chains and
shackles manufactured by the contractor, and submitted for
approval.
At the depot are a great many buoys of all kinds, most
of them of timber, but I believe none are now made of that
material. Some of the different kinds are the "nun," ucan re-
versed," "can," " egg-bottom," "convex bottom," "flat bot-
tom," "hollow bottom," " spherical," and "conical."
The English can-buoy corresponds in shape to our
nun-buoy, except that the larger end is in the air. The
cylindrical buoys used by the English are much like our
can-buoy, and are said to satisfy all conditions required.
An English nun-buoy is conical at both ends and is used
to mark wrecks. An English flat-bottom buoy is, as are
some of the others, water-ballasted, i. e., they have a cross
diaphragm at a proper distance from the bottom, and the
water is allowed to flow in and out of the lower compart-
ment thus made through eight holes an inch in diameter,
placed at equal distance around its sides. The water can-
not be discharged unless the buoy is careened for some time,
and it is therefore as completely ballasted as if the water
had no means of exit.
When those buoys are required for deep water where the
weight of the rnooi ing-chain is sufficient for ballast, water-
ballast is not used, and the holes are plugged with hard
wood. With the increased buoyancy thus obtained the
same line of flotation as in shoal water is approximately
attained.
This is a matter of importance, preserving, as it does, a
uniformity of appearance in each class of buoys, irrespective
of the depth of water in which they are moored.
The buoys said to be the best for strong tideways are the
can, cylindrical, and flat bottom; for exposed channels and
coasts the egg-bottom is used.
Another which is used with satisfactory results is a pat- Herbert's buoy,
ent hollow-bottomed one, called " Herbert's " buoy.
Buoys.
Names.
Can-buoy.
Cylindrical.
Nun.
F 1 a t - b o ttom
water- ballasting.
when
buoys
Best buoys for
96 EUROPEAN LIGHT-HOUSE SYSTEMS.
The theory of the action of this buoy is that the air con-
fined in the bottom forms an elastic spring upon which the
buoy rebounds in gentle and easy motions, causing but mod-
erate friction to the mooring- chain, little or no pull upon
the sinker, and a corresponding relief from agitation or fric-
tion to the globe and staff above.
size of buoys. I was especially struck with, the great size of some of the
buoys which I saw at Blackwall and at other places, many
of them being 20 feet in length.
iShbruog80f En~ Tlie En£lisl1 ordinarily moor their buoys by a single chain
and sinker or mushroom, but in some instances double moor-
ings are used. The chains of light- ships, after three years'
service as such, are converted into buoy-chains. The pro-
portion of chain used in mooring buoys is generally three
times the depth of water.
shifting buoys. Small buoys are shifted twice a year, but the buoys above
8 feet remain at their stations for two or three years and
are painted at their anchorage periodically.
served* fiTbuoV- ^e f°H°wing *s the system observed in buoying chan-
ing English wa- nfkjg •
ters.
sides of chan. The side of the channel is to be considered starboard or
port with reference to the entrance to any port from sea-
ward.
Entrance to. The entrances of channels or turning-points are marked
by conical buoys with or without staff and globe or triangle,
cage, &c. Singled-colored can-buoys, either black or red,
mark the starboard side, and buoys of the same shape and
color, either checkered or vertically striped with white, mark
the port side $ further distinctions are given when required,
by the use of conical buoys with or without staff and globe,
or cage, globes being on the starboard and cages on the
port hand.
Middle ground. Where a middle ground exists in a channel each end of it
is marked by a buoy of the color in use in that channel, but
with annular bands of white and with or without staff and
diamond or triangle, as may be desirable ; in case of its be-
ing of such extent as to require intermediate buoys, they are
colored &s if on the sides of a channel. When required, the
outer buoy is marked by a staff and diamond, and the inner
one by a staff and triangle.
wrecks. Wrecks are marked by green nun-buoys.
Marks. Each buoy is plainly marked with a running number and
the name of the locality where it belongs.
The white stripes or checkers of buoys are about 20 per
cent, less in size than the black and red, it being found that
EUROPEAN LIGHT-HOUSE SYSTEMS. 97
the characteristic, distinctions of the buoys are better ob-
served at a distance by this inequality.
Bell-buoys, of which there are many in use, are constructed Beii-buoys.
of iron, and have four hammers or clappers, each hung by
a Y, which prevents jamming and obviates the use of guides.
They cost about £200 ($1,000) each.
At Blackwall the buoys are kept under a commodious Buoy-shea.
buoy-shed, with convenient arrangements of rails, &c., for
moving them. The sinkers are square and of iron. The
prices of iron buoys most recently obtained are as follows : Pricesofbuoys.
Eight-foot drum-buoy, price £32 10s., ($162.50.)
Eight-foot spherical buoy, price £145, ($725.)
Eight-foot water-ballasting buoy, price £82 10s., ($412.50.)
Thirteen-foot water-ballasting buoy, price £198 6s. 8d.,
($991.66.)
Bell-buoy, price £224 12s., ($1,123.)
At the depot are two towers, each having a fixed lens of Towers in
which tests are
the second order, and in them are tested, under the direction made.
of Professor Tyndall or Mr. Douglass, the diiferent lamps,
lenses, and oils, the effect of fog, &c.
The principal point of observation is Greenwich, distant
about two miles.
There are several light-house depots on the coast of En-de^jt|h^nbo^
gland, at Yarmouth, Coquet Island, an cj other places, but coastofEu»laud-
Blackwall is the principal depot for manufacture, supply,
and repair.
The immediate agents through which the authority ofei^1P>|rijj5^;
Trinity House is exercised are called superintendents, and House Districts.
each has some special duties assigned him, either the sole
care of the service in some specified part of the coast or the
charge of some special branch, such as the supply and store
houses at Blackwall. The tenders are under their orders, orders^? suife*
They wear a uniform on all occasions when on duty.
Light-keepers are appointed by the corporation. The Keepers.
rules require that applicants shall be between the ages of 19
and 28. They must produce certificates of character arid
physical ability, and (from a schoolmaster) of ability to
read, write, and perform simple operations of arithmetic.
As vacancies occur successful applicants are taken on pro-ries.up
bation, i. <?., are appointed supernumerary light-keepers.
They are then sent to the depot at Blackwall and placed Instructioll to
under the orders of tlie superintendent there. They
carefully trained in the use and care of lamps and all light-
house apparatus, including meteorological instruments 5 the
keeping of the light-house journal and accounts, and the
general management of affairs at a light-house.
S. Ex. 54 7
98 EUROPEAN LIGHT-HOUSE SYSTEMS.
certificates A certificate of the lowest grade is given for competency
given. . , . , . .
in their duties.
A second course of instruction includes the use of tools in
carpentry and plumbing, that he may be able to effect
ordinary repairs ; also the management and general knowl-
edge of the steam-engine.
A third course includes instruction in the management of
the magneto-electric machine and lamp.
A fourth course includes the use and management of fog-
horn apparatus.
Separate certificates are given for each course.
^nere are alway s ci ght of these candidates for light-keepers
and at Blackwall, and two at South Foreland, the latter for in-
South Foreland.
struction in the management of electric lights, and to the
great care exercised in their selection, and the thorough-
ness with which they are instructed before they enter upon
their duties as keepers, is to be attributed the excellent
condition of the lights, towers, dwellings, and grounds that
I observed at every station which I afterward visited.
Supernumera- Supernumeraries are supplied with uniforms, and are
and paidnif°?med paid at the rate of £45 ($225) per annum ; but on obtaining
the four certificates and giving satisfactory proofs of steadi-
ness and sobriety, they become entitled to an assistant
keeper's pay.
The rates of pay are as follows :
Grade of keeper.
<D .
s-t a
p
II
§2
Is
p
Principals who have served as such above 10 years if insured
£ s.
72 0
£ s
3 0
Principals who have served as such above 10 years, if uninsured
70 10
63 0
0 0
3 0
Principals above 5 and under 10 years if uninsured
66 10
0 0
66 0
3 0
Principals under 5 years if uninsured
64 10
0 0
Assistant keepers who have served as such above 10 years, if insured. .
Assistant keepers who have served as such above 10 years, if uninsured
Assistant keepers above 5 and under 10 years if insured
58 0
56 10
56 0
3 0
0 0
3 0
54 10
0 0
54 0
3 0
Assistant keepers under 5 years if uninsured
52 10
0 0
g. Keepers pen- When no longer able to do service, keepers are pensioned,
the pension computed on an estimated allowance of £18, in
addition to the above scale.
Term of service Keepers and assistants at rock and screw-pile stations
screw-pile sta- remain on shore, in rotation, one month each.
The regulations in regard to the care of lamps and prem-
ises and keeping watch are much the same as our own, but
where mineral-oil is used, the following instructions are
added :
EUROPEAN LIGHT-HOUSE SYSTEMS. 99
u The oil is to be placed iD the metallic cisterns provided careofmmerai-
for the purpose ; and these are to be kept perfectly closed 01
by means of the cover and tops with which they are pro-
vided. In drawing oil from the cisterns it is to be drawn
into a proper can, provided with an oil-tight screwed cover
and au air-tight screwed cap to the spout. After charging
the lamps the can is to be returned to the store with the
covers, spout, and top screwed tight. All oil required for
the service of the establishment is to be taken from the
store during day-light, and keepers are not, under any
circumstances, to enter the oil-room with a lighted lamp or
candle."
IRON LIGHT -HOUSES OFF THE MOUTH OF THE THAMES.
After leaving Blackwall we proceeded down the Thames ^fg™jse iu tho
in the Trinity House steam-yacht Vestal on a cruise of
inspection of the lights on the east coast of England, during
which we visited nearly all of them between the Thames
and the Scottish border. On this journey it was my good
fortune to accompany Admiral (Jollinson, 0. B., and Cap-
tain Weller, of the Elder Brethren, and I shall long remember
the great kindness and attention of which I was the recip-
ient from both of these gentlemen.
We passed the Mucking light-house, situated in the h Mucking light-
Thames, below Gravesend, and the Maplin Sand light-house,
off the mouth of that river. Both of these are screw-pile lighthouse.
structures ; the latter was, I believe, the second of that kind H^t house S'the
in the world, having been lighted in 1841, and was one
the earliest applications of that useful invention of Mitchell,
of which we have many examples, there being more than Number of
fifty light-houses built on that plan in the United States, houses1" in 1Sthe
It may be mentioned here that the first screw-pile light-
Maplin Sand
hous
house was built at the mouth of the river Wyre, on thelighWlonsebuilt-
northwest coast of England, two^or three years before the
light-house on the Maplin Sand. The screws were three
feet in diameter, the piles five inches ; and above the ground,
instead of iron, as at Maplin, wooden columns were used.
This light- house was destroyed in 1870. st™" ed n de"
The Maplin Sand light-house, a view of which is shown Description of
in Plate Y, is a hexagonal structure, with one central and
eight exterior piles. The piles were driven vertically, but
above the water-line they bend toward the. center and in-
cline in a pyramidal form to the lantern-floor. The screws screws.
are four feet in diameter, the piles five*' inches, and they
support cast-iron columns 12 inches iu diameter. The col- columns.
100 EUROPEAN LIGHT-HOUSE SYSTEMS.
umns are very strongly braced, and the structure had an
appearance of great strength.
Gnnfleet light- We stopped . at the Gunfleet light-house, situated on a
sand of that name, north of the mouth of the Thames, and
thirty-one miles from the Nore light-ship. It is exposed to
the full force of the Korth Sea.
Plies. There are one central and six exterior piles supporting
columns of about 12 inches in diameter, strongly braced.
sockets. The sockets for the columns are not cast in one with the
sockets for the braces, but the latter are bolted against the
face of the piles by tap-bolts.
Form of the Unlike Maplin Sand light house, the > piles were not driven
structure.
vertically, and are inclined from the bottom to the top in
the form of a pyramid. The piles, braces, and sockets are
of a very massive character, and give an appearance of
great durability and of the strength which the site demands.
^Keepers' dwell- rpne Dwelling for the keepers (below the lantern-floor) is
but one story in height, and is smaller and less convenient
than in similar structures in the United States. The sides
and roof are made of corrugated iron with wrought-iron
Additionaiail<yie_piates. Below the floor of the dwelling additional
space furnished. &
space is furnished by placing a store-room in an inverted
pyramid, to which access is had by a ladder from the gallery.
The dwelling is divided into a living room, (also used as a
Reason ibr the kitchen,) a bed-room, and an oil-room. It was stated that
thTs™ucture.m° the sea rarely rises to the bottom of the house, and the ob-
ject of the peculiar form given was to allow the wind and
spray to be warded off without imparting shocks to the
structure. I should judge the device to be one of question-
able utility, and that but little more expense would have
been incurred by raising the building a few feet higher and
placing another full story for the accommodation of the
keepers.
Keepers. There are two keepers, one less than we would have in
the United States, and it will be observed throughout this
report that the British lights are maintained by a less num-
ber of keepers for each than for the same order of light in
our service.
catoptric ap- The lantern, which is large and commodious, contains a
paiatus m- revojving catOptric apparatus composed of fifteen reflectors
and Argand burners in sets of five, placed on a frame of
Red light, how three sides, and this being a red light, panes of red glass, in
managed. frames hung on hinges, were placed in front of each reflector.
This structure seems admirably adapted to the locality, and
1 should think the question of replacing by similar struc-
s! tures some of the great number of light-ships which mark
Plate V.
^s
I
. ^
' '"
• •'".
MAPLIN SAND LIGHT-HOUSE.
EUROPEAN LIGHT-HOUSE SYSTEMS. 101
the channels through the shoals obstructing navigation on
the east coast of England, would have attracted attention,
and there are probably some special reasons why it has not
been done.
While the first cost of a screw-pile light-house in an ex- comparative
posed locality is greater than that of a light-ship, the cost flight -Sis
of maintenance as well as of repairs is much less ; and be- aml
sides, the danger which sometimes occurs of light-ships
being dragged from their stations and leading vessels into
the very dangers from which they are intended to warn
them, is avoided.
These considerations have induced us to replace our
light-ships by screw-pile light-houses except in the case of
shifting shoals like those off the island of Nantucket.
ORFORDNESS.
We did not visit these light houses, but as viewed from
seaward they are substantial structures. Seen in one, in
either direction, they guide clear of certain dangers ; and H^Sfhouses *at
besides this, they mark out, by means of red sectors of light, Orfordness-
other dangers. This was the first instance I saw of what "Redcuts-"
the Elder Brethren call " red cuts," which I shall fully de-
scribe when I come to treat of the lights at Souter Point and
Coquet Island. We ran from the white into the red light,
and the line of division was quite distinct.
YARMOUTH.
On the 12th of June we arrived at Yarmouth, where there r>epot at Yar-
is an extensive supply and buoy depot on the river Yare.
It consists of a very fine buoy store-house, a store-house for
chain-cables, a cooper-shop for wooden buoys, smith and
paint shops, a store-house for oil, slips for the repair of light-
ships, and quarters for the superintendent, foremen, and
clerks. There is also a fire-proof store-house for the signal-
rockets used on the light-ships.
The buoy store-house is well built of masonry, paved with Buoy store-
wooden blocks, and traversed by a railway. A trussed
traveling-crane, of excellent construction, supported on
girders resting on piers projecting from the side-walls, gives
great facility for moving the buoys ; large sliding-doors
open toward the river, and on the wharf is placed a ten-ton
crane for hoisting the buoys into the steam-yacht, Beacon,
Yacht Beacon.
which, with its steam-launch or pinnace, is constantly en-
gaged in the service of the district under the superintend-
ence of Mr. Emerson.
102
EUROPEAN LIGHT-HOUSE SYSTEMS.
Buoys repaired. At this depot are painted and repaired the buoys for the
neighboring coast and channels, and a large number are
kept in store for relief and to supply losses.
brouTte\ibeach ^oe wooden buoys (not spar-buoys ; of these I believe the
year. English have none) are brought in once a year for painting,
iron buoy s but the iron buoys are painted without being unshackled
painted at their
moorings. from their moorings, and are but rarelv ch an fired. The
Marking
buoys.
depot™ 1
5,) provided
Fig. 5.
with
from their moorings, and are but rarely changed.
of buoys are marked with their numbers and names; these
last being the names of the spits, channels, &c., which they
are intended to point out. A practice very different from our
own is that of painting these numbers and names on
heavy canvas strips of two thicknesses, which are fastened
to the buoys by means of bolts and nuts, or by lashings.
These strips are frequently changed, (without lifting the
buoys,) as it is considered of great importance that the
names and numbers of the buoys shall always be plain and
distinct.
Method of deter- There are a great many buoys and several light-ships
- ships in view from the high lookout- tower above the dwelling of
1 in the superintendent, and Mr. Emerson has contrived a simple
and ingenious mode of detecting if any of them have been
driven from their positions.
A large telescope, (shown in Fig.
spider-lines, is movable on
a vertical axis, c, fixed upon
a platform on which are
marked cross-lines c a, c a,
c a, and the names of the
buoys and light- ships, which
indicate the precise direc-
tion in which they should be
found by means of a pointer,
c &, attached to the pedestal
of the telescope; thus the
slightest drifting from their
proper positions is at once " Buoy-finder. ~
discovered.
In regard to buoys, I should mention that the buoy-list
of the English differs in several respects from our own.
There is noted in regard to each buoy its name, size, descrip-
tion, (kind,) color, material, weight of sinker, fathoms of chain,
depth of water, when first laid, and date of last removal.
The following is an example :
EUROPEAN LIGHT-HOUSE SYSTEMS.
103
Remarks.
Color altered from white, 1859.
Name and color altered, 1869.
Color altered, 1869.
Color altered, 18G9.
1
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Black
Black and white checkered . .
Red and white striped
Red and white checkered . . .
Red and white striped
(description) of buoys : H. B.
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Checkered Fairway . . .
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104
EUROPEAN LIGHT-HOUSE SYSTEMS.
A spare light- ship is kept at Yarmouth depot, and I saw
one repairing in the dock. The bottom was exposed, and
was provided with bilge-pieces or " bilge-keels " to prevent
rolling, as shown in Fig. G.
Fig. 6.
Position.
Bilge-keels for Light-ships.
1 was informed that this was the common practice in the
English service.
HAlSBOROUaH.
There are two first-order sea-coast fixed lights at Hais-
borough, in the county of Norfolk, the northern or high
light being 140 feet, the southern or low light 94 feet, above
the sea. They are about a mile apart and form a range or
lead for vessels passing through Haisborough Gat.
Competitive At the time of my visit to this station there had been in
trial of gas and „ . ,. .. , . ,
Douglass^ four- progress for some months an important competitive trial
*mp~ between a Douglass four-wick lamp in the low tower and a
gas-lamp, patented by Mr. Wigham, of Dublin, in the high
tower. The apparatus for the latter was manufactured by
Edmundson & Co., engineers, of London and Dublin.
The commissioners of Irish lights have introduced the
use of gas into several of their light-houses, as we were in-
formed by Professor Tyndall when he was in the United
States last year, and in the remarks which he made at a
of session of the Philosophical Society of Washington, he
mentioned the great " flexibility " of this kind of light when
used for light-house illumination.
I will treat more particularly of this invention of Mr.
Wigham when I describe the Irish lights that I visited with
him, but I will state here that 1 found the lamp to consist
of a horizontal circular disk (hollow) about one foot in
diameter, supported upon a stand and into which the tubes
Gas in use in
Irish light-
Louses.
Flexibility
gas-light.
Lamp.
EUROPEAN LIGHT-HOUSE SYSTEMS. 105
supplying the burners, in sets or frames, were connected by
joints made tight by means of quicksilver.
The lamp is designed to burn 28 jets in clear weather. Arrangement
They are arranged in concentric rings, the diameter of°
the inner row being about the same as that of the outer
burner of the ordinary four- wick lamp, i. <?., four inches.
In case the atmosphere becomes hazy, an additional exte- increase of
rior row of 20 jets is placed in two frames of 180° each, nv
each frame being supported by a short supply-tube set into
a cup containing a quicksilver joint.
During this operation the lights from the 28 jets forming
the nucleus are turned low, and when the cocks are re-
opened the flame from these lights the exterior row.
As required by increasing density of fogs or thick weather,
additional rows of jets are successively placed in each case,
increasing the number by 20, so that from 28, the number
in the nucleus, the various powers are 48, 68, 88, and 108
jets, the latter being used only in very thick weather or
dense fog.
There is no chimney surrounding the flame, but above it, ciiimney o,
at a distance of about 12 inches, is suspended a chimney of mica-
mica, into which the flame is carried by the draught through
the cowl of the lantern. The mica chimneys vary in diam-
eter, and are changed to accord with the number of jets
used.
The entire operation of changing from one set of jets to Tirae OCCUpieA
the next higher or lower, or from the lowest to the highest, JjJfiJJgJt81*0*"
or the reverse, and also changing the mica chimneys, occu-
pies but a few seconds, not more time, I should think, than
the trimming of a four-wick lamp.
The diameter of the flames corresponding to the different Diameters of
powers of the lamp are respectively 3f, 5J, 7J, 9J, and 10£ tho flaraes'
inches for the 28, 48, G8, 88, and 108 jets. It will therefore
be observed that a, great part of the larger flames is neces-
sarily exfocal, increasing the divergence of the light, and
the increase of intensity when seen at any point within the
arc of visibility is no doubt due to the great thiclcness of the
flame.
The heat inside the lantern, when the larger flames are Heat produced
turned on, is very great, but I was told that it was not 8»f-|L»2f largest
ficient to injure the lenticular apparatus nor to seriously
aimoy the keepers.
As in the electric light at South Foreland, an oil-lamp is ou-iamp on
T .L i -i • >i i i ' /> hand in case of
always at hand in the watch-room, and in case ot accident accident,
to the gas-lamp, it can be removed and the former lighted
in less than two minutes. I did not learn that occasion for
106 EUROPEAN LIGHT-HOUSE SYSTEMS.
its use had yet occurred, and I should think it even less
likely to occur here than in the case of the electric light.
Coal used. In the gas-house near the tower common Newcastle coals
are used for heating the five retorts, and canuel-coal yields
the supply of gas.
Gas, bow con- The gas issuing from the retorts is, after being caused to
ducted to the re-
ceivers. pass through water, conducted through several layers of
slaked lime contained in flat boxes, thence through a sys-
tem of pipes, depositing the tar-product en route, and finally
is carried into the receivers (of 4,900 cubic feet capacity)
from which the light-house lamps are supplied.
Meters. Separate meters are used for registering the quantities of
gas consumed in the dwellings and in the light-house, and
con- each amount is reported monthly to the Trinity House. The
s' consumption of gas in the 48-jet burner, in a night of 7J
hours, was 830 feet, or 2.3 feet per burner per hour.
Consumption In the months of April and May preceding my visit the
Say, iB73. " consumption of gas in the tower had been 21,980 and 26,450
feet respectively.
Number of There are two keepers at each light-house at Haisborough,
(that being the rule for all English sea-coast lights, except
Laborer em- rock-stations,) and in addition to them is employed a laborer
from the neighboring village, to make the gas, but his
attendance at the station is only required every other day.
He is paid a weekly salary of fifteen shillings, (about $3:75.)
Fuel saved by ^ large saving in fuel is effected by consuming the tar
which is produced in the manufacture of the gas.
A general plan of the buildings at the light-house is
shown in Plate VI.
Plan of tower. The tower is built of brick and stuccoed ; it and the dwell-
ings, out-buildings, and walls surrounding the premises are
kept scrupulously clean and neat.
stairs. The interior of the tower is cylindrical ; the stairs, like
those in the towers at South Foreland, are circular, and
apparently self-supporting, one end only being built into
the wall, as in our Treasury at Washington, and in several
other buildings I have seen in America. This method of
stair-building I found to be universal in Europe, in private
comparison of as well as public buildings. I think our most recent towers
tor?, with conical interior and iron stairs winding around the
interior of the cone, superior to any I saw in Europe.
European towers are, however, superior to any constructed
by us until within a few years, on account of the greater
amount of light and the airiness of towers with a free and
open interior.
EUROPEAN LIGHT-HOUSE SYSTEMS. 107
The practice abroad is, in most cases, to make the interior
wall cylindrical and the exterior one conical, leaving1 an un-
necessarily large air-space between the two near the base,
while in our latest towers, such as those at Bodie's Island,
Saint Augustine, and others, a small air-space sufficiently
large for the purpose intended is left between the walls,
(both of which are conical,) and the space gained by this
mode of construction is thrown into the interior.
The amount of masonry in our present system is the same Masonry in old
as in the former, and is calculated to resist by its weight SJS
the overturning effect of the severest gales.
At Haisborough the oil-cellars are placed below the floor Oil-c
of the towers, the cisterns or cans, each holding about 100
gallons, being arranged around the walls. There are no
arrangements for pumping the oil to the top of the towers,
and it is carried by the keepers by hand. The filling-room Measures to
below the lantern is provided with brass measures of differ-
ent sizes, from a gallon downward, and every morning the
keeper notes the consumption of oil the previous night, and
makes monthly returns of the amounts to the Trinity House.
These measuring- vessels, the brass-work of the lamp, and
the hand-rails of the stairs, are always neatly burnished.
The English lanterns in all the recent light-houses have ba?8i.agonal 8ash"
diagonal sash-bars, as it is considered that the upright bars
obstruct a large portion of the light in certain directions.
I will more fully treat of the latest lanterns which I saw,
and particularly of the advantages of the diagonal sash-bars,
when I come to describe the light-house at Holyhead.
The glass for the lanterns at Haisborough is half an inch Glass for ian-
thick, the panes are lozenge-shaped, and the surfaces are te
curved to conform to the diameter of the lantern.
No special means are used to prevent large sea-fowl from
breaking the lantern-glass, and I was told that the necessity
of such means does not exist in England as it does with us,
particularly on our southern coast.
In the Ian tern -floor there is provided a basin, covered Basin in ian-
when not in use, into which is led rain-water from the roof tern~floor*
for use in washing the interior of the lantern.
The air, which supports the combustion of the lamp, is Egress of air.
not let directly through the sides of the lantern, as in our
service, but is admitted below and passes through the grat-
ing which forms the lantern-floor. The object in this is to
give the air a uniform temperature, and great importance is
attached to this in the English service. (See Plate VII.)
The windows of the tower are arranged without admit- Method of veu-
ting the rain, according to an excellent plan which is shown tilation-
' 108 EUROPEAN LIGHT-HOUSB SYSTEMS.
in Plate VIII, in which it will. be^observed that the upper
sash is hinged afc a-, and savings, as shown by the dotted arc.
To the lower part of the sash is- fastened a rod, b, which
passes through a sleeve, c, whicti is movable about an axis,
and through which a set screw passes by which the window
can be fastened atr any desired angle. One only of the
lower sashes opens, as is shown in the -plate.
cost of chang- The costof changing from oil to gas at Haisborough was
£51 light. c ° about £1,700, ($8,500,) the gas-holder and other parts of
the apparatus being designed to serve both lights.
Painting the in the English service the towers and dwellings are gen-
dwellings, &c.,
periodically. erally painted white (to make them serve better as day-
marks) once in four years, by painters permanently em-
ployed by the Trinity House, and who for this purpose visit
the stations in rotation.
The lantern, watch-room, &c., are painted by the keepers
on'ce a year. The hand-rails, when of iron, are painted with
bronze paint, and when they are of brass, which is often the
case, they are kept neatly burnished.
wind-vanes At the summit of the lanterns are always placed wind-
and lightning- IT i , •
rods. vanes and lightning-rods.
Flag-staffs. Flag-staffs are provided at each station, placed either on
the tower or in the grounds surrounding it. The Trinity-
House flag is displayed whenever the tenders are seen ap-
proaching; also on Sundays and holidays. I observed that .
a neat pavement of pebbles,' about 15 inches wide, was. --
laid at the foot of each wall, to protect the soil from the
wash from the wall in rainy weather.
Rooms fur- In regard to the dwellings, each keeper is furnished with
^ keepers. a ijving.room? three bed-rooms, a scullery, wash-room, a
place for coals, and a garden.
Books at the There are at Haisborough, as at all other light-stations
in the English service, certain books furnished by the
Trinity House in which are kept the records of the stations.
Among them I observed an Order- Book, in which any
officer of the corporation enters the orders or directions
given by him to the keeper while on his visit to the station.
It is his duty to observe whether previous orders of himself
or others have been properly executed.
Another book is called the Visitors' Book, and in it are
recorded the names and professions of the persons visiting
the station.
Libraries. Small libraries are provided at each station for the use of
the keepers and their families. They always include a
Bible and Prayer-book, and are^therwise composed of books
suitable for persons of their class.
IS-T ORDER ENGLISH LIGHTHOUSE.
UPPER PART OF TOWER.
PLATE VII-
EUROPEAN LIGHT-HOUSE SYSTEMS. 109
These libraries are interchanged between the stations on
the annual visits of the supply-vessels.
Medicine-chests also are furnished to each station. Medicine-chests.
I did not observe any room set apart especially for a work- NO work-rooms
. .. „ . , , at English stn-
shop as at our large stations, though keepers are furnished tions.
with necessary tools, and their education at Blackwall in
mechanical operations would, with the general intelligence
possessed by the keepers, make this provision more useful
even than in our own service.
A certain amount of standing furniture is provided in Furniture.
each dwelling. It includes iron bedsteads, chairs, tables, a
desk, &c.
When a keeper is removed from one station to another
(either to a better one as a reward of merit, or to an inferior
one as a punishment) his family is transported at public
expense.
The keepers at Haisborough, as at all the other stations uniform wom
which I visited, wore the neat uniform of the Corporation of y
Trinity House.
From Haisborough we steamed out to the Xewarp ^to^-
ship, (to be noticed farther on,) and returned after dark to
observe from the sea the comparative intensities of the gas
and oil lights.
The gas-light is in the northern light-house, the oil-light
in the southern, on a point of land nearer the sea, at an ele-
vation 46 feet below the former, the respective heights of
focal planes being, as before stated, 140 and 94 feet above
the sea. The lower tower is lighted by one of Douglass's
four- wick lamps.
The Vestal was stopped at a distance of six and a half
miles from the lights, and at a point equidistant from both.
The night was clear, and the opportunity for fair-weather
observations was excellent. The Trinity House officers on
board had directed the keeper of the upper (the gas) light-
house to burn the ordinary number of jets,*viz, 48, till 9
o'clock. At that time the number of jets wras to be reduced
to 28, and the changes were to be as follows :
At 9 p. m. reduce to 28 jets ; at 9.10 p. m. increase to 48 Memoranda oi
jets; at 9.20 p. in. increase to 68 jets ; at 9.30 p. m. increase ch
to 88 jets ; at 9.40 p. m. increase to 108 jets ; at 9.50 p. in.
reduce to 28 jets; at 10 p. m. reduce to 68 jetsj at 10.10
p. m. reduce to 48 jets ; at 10.20 p. m. reduce to 28 jets 5 at •
10.30 p. m. increase to 48 jets.
The comparative brightness of the lights was estimated Manner of oi>-
by observing them with the naked eye, and also through fights.1 n fi
different thicknesses of red glass. The method of using
110 EUROPEAN LIGHT-HOUSE SYSTEMS.
the latter was to place successive layers of small plates of
glass into frames made for the purpose, until one or both of
thelights when seen through them could barely be discerned,
and I found that the eye could thus much more readily detect
differences between the intensities of the lights than when
viewing them without the use of the glass media.
Question of I am riot, however, satisfied as to the advisability of using
t fn t e'a n| ituSs red glass, since it is probable that those flames which have
chormTf ar^the more of that color in their composition would be placed at a
disadvantage, and I would prefer a neutral-tinted glass.
Appearance of When we first observed the lights from our position the
gas-light (48 jets) was not equal to the oil-light ; between
9 p. m. and 9.10 p. m. (28 jets) it was still more inferior ;
between 9.10 and 9.20 (48 jets) the same difference was ob-
served as before ; between 9.20 and 9.30 (68 jets) we pro-
nounced the two lights equal.
Fog obscures At this time a dense fog rolled in from seaward, obscuring
both lights, and we steamed toward them till we got within
(as we afterward found) two miles of them, both continuing
eclipsed. About midnight the fog rolled away, and the
lower (oil) light came gradually into view, but vvhen it had
apparently attained its full power we could still see no sign
of the upper (the gas) light.
Fifteen minutes afterward the upper light dimly ap-
peared and slowly increased in brightness till about half
superiority of past 12, when both lights were fairly free from the fog, and
hts' in the opinion of all the party the upper (gas) was very
much superior to the lower (oil) light.
As the time covered by the instructions given to the
keepers had long since expired, it was not until our return
London that we learned the number of gas-jets burning,
which was then shown to be 108, the number corresponding
to the instructions of the keepers for times of dense fog.
It was fortunate for our experiment that the fog shut in
during our observations. That the oil-light was first to be
seen was no doubt due to the fact that the fog rolled in over
the land from seaward, (though this was not apparent to us,
there being no perceptible breeze,) and that light, being on
a point projecting into the sea, was first free from it.
^s ^ar as determined by our experiments at Haisborough,
ration of lights. I have no doubt the following judgments were correct :
1st. In fair weather the gas-light of 68 jets was equal to
the first-order light from the oil-lamp of four wicks as im-
proved by Mr. Douglass.
2d. Neither. the light of 28 nor of 48 jets was equal, but
that of 108 jets was decidedly superior to the oil-light.
VENTILATING WINDOW
FOR
LIGHTHOUSE TOWERS.
PLATE VIII.
SECTION.
INSIDE ELEVATION.
ENLARGED DETAI L
FASTENING.
&
r>V
EUROPEAN LIGHT-HOUSE SYSTEMS. Ill
3d. In a dense fog, to an observer at a distance of two
miles, neither the gas-light of 108 jets nor the oil-light from
a four-wick burner gives any indication, however slight, of
its existence.
It has been observed by Professor Tyndall, in his experi- A slight cloud
•¥-» i I- 11 t -i ^n f°f steam snffi-
ments m Dublin, that a steam-cloud ot even a tew feet olcient to obscure
thickness is sufficient to totally obscure the rays of the sun
itself, and as either the four-wick oil-lamp or the 28-jet gas-
light is sufficiently powerful to illuminate the horizon cor-
responding to the ordinary elevations of sea-coast light-
houses, i. e., at distances from eighteen to twenty nautical
(twenty-one to twenty-three statute) miles in clear weather,
it is evident that the increased intensity of sea-coast lights
is desired for those intermediate states of the atmosphere
between dense fog on the one hand and clear weather on
the other.
In these conditions of the air, including all the varieties conditions of
of haziness and " thick" weather, up to dense fog, (and also
in snow-storms,) light-houses are most useful ; for these the
light-house engineers of Europe are striving to find the most siretL
powerful lights, and to meet this want the electric light
(which I have described at South Foreland, and which I
shall more clearly exhibit in an account of my visit to the
light-houses at the mouth of the Seine) and the gas-light
(such as I have described at Haisborough and afterward
saw on the coast of Ireland) have been introduced within a
few years.
While both these lights can be maintained at moderate Power of
power in fair weather, they have this advantage : they can lights can
. * , creased when
be increased almost without limit when it becomes hazy needed,
and thick ; this can be done without any increase in the
size or cost of the lenticular apparatus, since the electric
light requires a lens much smaller than that required for an
oil-lamp, and as I shall illustrate farther on, 324 jets can be
burned in Wigham's triform gas-light without increasing
the size of the lenticular apparatus or the diameter of the
flame beyond the maximum (108 jets) which I saw at Hais-
borough.
It is this power of being increased, (according to the con- Flexibility of
ditions of the weather, from 28 jets by steps of 20 at a time,
till 324 jets the beam from which, even when uncondensed,
is equal to more than the united beam from 6,000 can-
dles can throw their rays in a solid beam through the
lenticular apparatus,) which gives to the gas light of Mr.
Wigham its great " flexibility," to adopt the term so hap-
pily used by Professor Tyndall when speaking of this light,
112 EUROPEAN LIGHT-HOUSE SYSTEMS.
and I believe in this regard it is superior to the electric
light,
* Economy muse In the gas-light in clear weather only a sufficient quantity
of gas is used to carry the light distinctly to the horizon.
The large quantity required for " thick " weather remains
stored in the reservoir till wanted, and the expensive light
is burned only when needed, whereas in the electric light,
though the engine-power is doubled in " thick" weather, yet
the ordinary fair-weather expense of the engines is much
greater than the fair-weather cost of the gas light-houses ;
and, further, the gradations of power to which the gas-
light is subject are much more varied than in the electric
light, and the former can be suited by intelligent keepers to
any state of the atmosphere.
Absence of flex- Of course the oil-light which we use in the United States
light. has no " flexibility" and burns the same in fair weather as
in foul, in the twilight of the evening as in the darkness of
the night. This is a fact of very great importance in this
country, and particularly in high latitudes in Great Britain.
In the long twilights of the last summer, while between the
mouths of the Tyne and Tweed, I found no difficulty in
reading on the deck of the Vestal at half past 10 o'clock, and
indeed it could hardly have been said to be dark during the
entire night. In these long twilights and in clear nights
great economy can be attained in the use of illuminating
power, which can be stored up, as it were, to be used only
when the weather demands that it shall be put forth in all
its strength.
Question of the It is to be observed in this connection that the relative
gVowers'of So penetratfflg powers of the oil, the electric and gaslights,
noteiyett dfteS have not yet been sufficiently tested at a distance and in all
sorts of weather. This is a matter of great importance, and
should be made the subject of an exhaustive series of ex-
periments.
Almost any illuminant is good enough for fair weather,
but the light which will be finally adopted by all nations
will be that which will send its rays to the greatest distance
in storm and thick weather.
illustration of Tne gas referees of London, to whom the English Board
of°London?feree8of Trade have referred the matter of light-house illumina-
tion by gas, very cleverly illustrate this desideratum as fol-
lows :
" Suppose the case of two regiments armed in the main
with short-range rifles, but each comprising a body of
marksmen twenty in number in one regiment, and forty in
the other, armed with rifles of the longest range.
EUROPEAN LIGHT-HOUSE SYSTEMS. 113
{i At 1,200 yards the power of these regiments would be
represented solely by the numbers of their long-range rifle-
men— the power of the one at that distance being double
that of the other, although at close quarters their destroy-
ing-power would be equal.
u Every flame of gas or oil inaj7 be said to be a sheaf of
rays of various lengths or penetrating power, so that two
lights which are equal near to their source may become un-
equal when viewed from a distance; and an analogous effect
to that of distance will be produced by mists and fog, ob-
stacles wmi which it is most desirable that light-houses
should be able successfully to contend.'7
THE NEWARP LIGHT-SHIP.
This light-ship marks one of the sands which form a per- Position.
feet labyrinth off the coast of Norfolk and Lincolnshire. It
is built of wood, is registered as 212 tons builders' measure- Material ami
ment, and has three masts carrying fixed lights; the fore 81Lights.
and mizzen being 24, and the main-mast light 34 feet above
the sea. It is anchored in 17 fathoms of water by an anchor Moorinas
weighing 45 cwt., having 210 fathoms of IJ-inch chain, and
carries besides, two bower-anchors of 20 and 14 cwt. re--
spectively, with 150 fathoms of chain each.
The ship carries a Daboll fog-trumpet, which is sounded by e^abo11 trnni
means of an Ericsson hot-air engine with an 18-inch cylin-
der, placed below the deck and near the bow of the vessel.
Both the smoke-funnel and the trumpet are placed forward
of the foremast. The latter, which is removable, is kept
below deck when not in use; when sounding it revolves
once a minute.
A Chinese gong is provided for use in case of accident to Chinese gon-
the trumpet or engine, and it was sounding when we leftpr
the vessel, but we ran out of its range at a very short dis-
tance; I thought it inferior to the bells used in our light-
ships.
The trumpet was also sounded after we left the vessel, Trnmpetsound-
and although I judged it to be pitched at too high a note,
according to the conclusions arrived at in our American ex-
periments, we heard it with remarkable distinctness. At a
distance of two miles it sounded very loud and clear ; at six
miles the sound had sensibly decreased, but it was quite
audible when the Vestal was under way, and it was not
until we had gone eight miles that it ceased to be heard. mi^gard at eight
There was no wind to interfere with the sound, but my Fog-si Kuais
experience on this occasion satisfied me that, for localities 5|w^hi8^.ry °"
where fogs are as prevalent as at the stations occupied by
S. Ex. 54 8
114
EUROPEAN LIGHT-HOUSE SYSTEMS.
our light-ships off our northern coast and in Long Island
Sound, powerful fog-signals, operated by steam or hot-air,
would be extremely useful to the immense commerce depend-
ing on these vessels for safety.
Arrangements In order to assist in determining at night the direction
n!astshts °n thein which light-ships are riding at their anchors, the lights on
the mizzens are placed at lower elevations than those on the
main masts.
English light- In the English service each light-ship has the following
ships' crews. crew : one master, one mate, three lamp-lighters, and six
able seamen, one of whom may be a carpenter.* ISTO appli-
cants under thirty -two years of age are admitted.
Table of rates The following table shows the uniform rates of pay in the
of pay.
service :
i
1
sl*
1
'g'FrS
Kate per month.
p
ci|
.
o
^ S-i '"w
1
^>
p
III
£ s. d.
£ S. d.
£ s. d.
Masters, uninsured
6 13 4
000
000
Masters insured
6 15 10
050
000
Masters who have served as such five years and up-
ward . .
526
050
000
Masters who have served as such under five years . . .
Carpenters who have served as such five years and
4 10 6
050
000
upward
3 11 0
050
026
Carpenters who have served as such under five years
Lamp-lighters who have served as such five years and
386
050
0 2 G
upward
376
050
026
Lamp-lighters who have served as such under five
years .
330
050
026
Seameu who have served as such five years and up-
ward
300
050
026
Seamen who have served as such three years and
2 17 G
050
026
Seamen who have served as such under three years . .
2 17 G
050
000
Table of ra-
tions.
Uniform.
The master furnishes the provisions per the following
table :
Meat, 10 pounds per week each man.
Bread, 7 pounds per week each man.
Flour, 2 pounds per week each man.
Peas, 1 pint per week each man.
Potatoes, 7 pounds per week each man.
Suet, J pound per week each man.
Tea. 2 ounces per week each man.
Sugar, f pound per week each man.
Beer, 3 gallons per week each man.
When on shore is. Id. per day is allowed each man in lieu
of provisions.
The master and mate are furnished a regulation uniform-
suit, and the crew a cap, one shirt, and one pair of trousers
EUROPEAN LIGHT-HOUSE SYSTEMS. 115
annually. When unfit for longer service they receive a pen-
siou, computed on length of service, varying from 4J$. to Is.
per day. Their pay and allowances for this service is much
better than those of either the royal navy or the merchant-
service.
Either .the master or mate must remain on board. On
third of the crew is on shore at a time, the relief occurring once third? of c™w *°
remain on board.
a month. They must remain near the shore-station, with
the officer (master or mate) on shore at the time, and execute
such service as may be required, and, if the vessel goes
adrift, join her as soon as possible. If vessels are observed
in distress guns are fired, and if at night, rockets are thrown •
until assistance approaches. Careful and regular observa-
tions with meteorological instruments are taken on light be taken-
vessels as well as at light-houses.
The officer in charge on light-ships, at light-houses, and in
the Trinity House yachts are required to assemble the men church-service.
under his orders every Sunday, (when they have no oppor-
tunity of attending church,) and to read the church-service for
the day and a sermon or homily from a volume provided by
the Trinity House for the purpose ; when one of the Elder orany member
Brethern is present on Sunday the church-service is read by re^prlS^"
him.
THE COCKLE LIGHT-SHIP.
This light-ship, which we visited on our return from the Position.
north, is placed at the northern entrance to Yarmouth
Eoad. It is 155 tons measurement, is built of wood, and is Material,
measurement,
anchored in seven fathoms of water. It carries a revolving and moorings.
white light which is produced from nine reflectors arranged
on three faces ; three reflectors on each. The interval be-
tween flashes is one minute.
This is one of several light-ships of this kind which I saw Preferable to
in my journeys around the English and Irish coasts, and
they are, no doubt, much more useful in attracting the at-
tention of the mariner than light-ships with fixed lights.
We passed the Cockle at night, and I had a good oppor- Daboiitmmpet
tunity of seeing the light. It lies about six miles from the NewanTd heard
Kewarp, and the crew state that in light winds and clear SxmSes. Cockle>
weather the Daboll trumpet of the latter can be heard with
great distinctness, but that fog " kills " the sound to a great
degree.
SPURN POINT.
Spurn Point is a low sand-spit, projecting into the mouth Range-lights.
of the river H umber. There are two towers at this station,
and they form a double range or " lead/' the outside one
116
EUROPEAN LIGHT-HOUSE SYSTEMS.
Number
ranffe-lights
being effected by the eclipse of the inner light by the outer
tower.
<^f The number of stations on the east coast of England
. with two towers, many of them with first-order lights, form-
ing ranges or leads, is noticeable, and is accounted for by
the intricacies of the channels between the sands and shoals
off the coast, and their distance from the land.
hiShDtowertion°f The hi3n or main tight-tower was built in 1776 by John
Smeaton, the builder of the Eddystone light-house, and is
as unlike the graceful light-house towers of the present day
as can well be imagined.
The rooms are very large. The lower story 'only is arched
over, and is used for an oil-room, while the upper rooms
serve for the families of the keepers, and one is used as a
for chapel for the keepers, coast-guardsmen, and fishermen who
live at the Point.
The lens is of the first order, and a part of the arc of
illumination is covered by white light, while certain dangers
are marked by a red sector. The red glass in this light
covers the required arc of the lens, and is fastened to its
frame, but in order to sharpen the " cuts " between the red
and white light, narrow strips of red glass are placed in the
lantern opposite the edges of the red glass outside the lens,
as is shown in Fig. 7, in which a a a is the shade of red
i-eeberspel
Lens,
Red cut.
house list.
Red cut at Spurn Point.
glass of the entire height of the lens ; 1) 1) vertical strips of
red glass for the purpose of intensifying the " red cut ;? c
the lamp, a the sector of red light.
f Tlie foUowing, copied from the British light-house list, will
suggest the purpose of this mode of covering by red light
any desired area, and of marking by the cuts between the
Hgh
EUROPEAN LIGHT-HOUSE SYSTEMS. 117
red and white lights any line upon the sea within the circle
of illumination :
u SPURN POINT. — A sector of red light is thrown from the
high light-house bearing from N. W. by N., (cutting two cables
•N. E. of the Sand Hayle buoy,) round northerly to S. E. by E.
J E., on which bearing it ivill cut one cable north of Grimsby
Pier. In other directions the light is white."
The oil in use at this station when I visited it was colza, Coiza-oii used.
bat I believe it is the intention to change this and all the Mineral to be
other lamps in the service of the corporation of Trinity ST3
House for the use of mineral-oil.
The lantern was a fine one of gun-metal, the sash-bars Lantern.
being diagonal. The diameter is 14 feet.
The service-room was fitted up with closets and shelves, service-room.
and the articles for daily use are neatly stowed away in
boxes marked "Cleaning-cloths," u Skins," " Powder and
brushes," u Cotton wicks," u Polishing-powder for brass and
copper," &c.
The lens is supported by the lantern-floor, which is carried Lens,
upon eight double iron brackets, and the interior of the
watch-room is finished in corrugated iron.
The station, comprising the lower dwelling, &c., is sur- wall Around
rounded by a high wall similar to that at the Longstone,
(mentioned farther on,) but for a different purpose, viz, to
keep out the drifting sand.
The lower light-house is a comparatively new structure, L ow e r light-
and was built in shoal water inside the main tower, as a sub-
stitute for the tower which Smeaton built outside the high
light which was some years ago undermined and destroyed
by the sea.
The apparatus in this tower is of the fourth order. Apparatus.
FLAMBOROUGH HEAD.
This part of the Yorkshire coast is high and bold, resem- Appearance of
bling the coast of California.
I was interested, not only in the inspection of the fine oui tower for
. _X . burning coal still
new tower on this remarkable headland, but in seeing near standing.
by a well-preserved example (built in 1674) of one of
those great coal-burning light-towers whose use preceded
the invention of either of the systems of illumination now
in use; from this tower was witnessed the naval battle
between the Serapis and the Bon Homme Richard, which
was fought off this headland on the 23d of September, 1799.
118 EUROPEAN LIGHT-HOUSE SYSTEMS.
Height of focal The focal plane of the new tower is 214 feet above the sea,
and 87 feet above its base. The tower is surmounted by a
Characteristics
of lens. first-order revolving lens, showing, alternately, one red and
two white Cashes.
Quality of lens, This lens, made by Chance, Brothers & Co., of Birming-
ham, is a fine piece of workmanship, and the Trinity House
officers state that all of the optical apparatus furnished by
this firm give great satisfaction.
Areas of red The area of each of the red panels, is to the area of each
ami white panels. J
of the white panels of the lens, as 21 to 9, thereby pro-
ducing an equalization of the distances at which the flashes
can be seen.
Lamp- The lamp was one of the latest, combining all of Dong-
lass's improvements, and burned mineral-oil, though it is
suited also for burning colza.
The lantern is of the same character as that at Hais-
borough, which I have described, and there were no points
of special interest at this'station that were not mentioned in
connection with that light, except that on the edge of the
ti(?D0gguI a bluff there is a fog-gun station, in charge of a special set
of keepers, (two,) who have dwellings and gardens separate
from those at the light-station.
^ Jog-gun, how The gun, an 18-pounder, is in a small masonry building
having an embrasure on the sea-side 5 it is fired at intervals
of fifteen minutes in foggy weather, the charges being three
pounds. About one thousand rounds are fired annually,
and they are kept in ready-filled cartridges in barrels in the
magazine. The gunners have no other duties.
WHITBY.
These two first-order lights are on the coast of Yorkshire,
and, like the Haisborough lights, form a range or head
which clears a dangerous rock.
The towers are about 250 yards apart. A red cut shown
Red cut.
from the northern tower covers certain other dangers to be
avoided by vessels.
Fastening for The mode of fastening the red panes, so that they can be
easily removed for cleaning the lens, is very simple, as will
be seen in Fig. 8, consisting of a turning-plate, which, when
shut, rests on a slight projection.
Another simple contrivance in use was a movable metal-
lic guard, which is slipped over the burner before the wick
is trimmed, so as to catch the cuttings. (See Fig. 9.)
The stairs leading from the watch-room to the lantern
were noticeable, the step, newel-post, and ornamental bracket
being cast in one piece.
EUROPEAN LIGHT-HOUSE SYSTEMS.
119
The smoke-pipe leading from the watch-room stove was smoke-pipe.
of brass neatly burnished.
The dwellings for the keepers (each light having two) in^8eeper8' dwe11'
were placed on opposite sides of each tower, and the rule is
general that each keeper has a dwelling quite separate and
detached from any other.
Fig. 8.
Fastening for red panes.
The dwellings at Whitby — and this is also the rule — are
only one story in height.
There was nothing noticeable in regard to the lenses,
except the large amount of rear light (i. e. through an arc
of. 180°) not utilized, and I was informed that formerly the Reflector for-
land side of the lens was occupied by a metallic reflector, throwmgtberear
which, reflecting the heat as well as the light from the flame, lfi
caused the wick to burn so much more freely on the rear
side than on the other as seriously to impair the light.
Fig. 9.
r MlllliyHlllllllUI]
Lamp-guard.
Totally reflecting glass prisms, such as are now used in
light- houses, would not produce this effect, but they have
not as yet been supplied.
I learned at Whitby that one of the light-keepers has dis- Method of pre-
paring g 1 n s s
covered in his experience that dipping the lamp-chimneys in chimneys to re-
a hot solution of soda will prevent them from breaking
even when exposed to the strongest flames.
120
EUROPEAN LIGHT-HOUSE SYSTEMS.
Town of "Whit- Not far from the light-bouse is the town of Whitbv* inter-
V
Euinsof Abbey osting ouaccount of the ruin of the once handsome Abbey of
Saint Hilda, (founded A. D. 657,) the extensive commerce
in jet, mined from the cliffs near by, and as being the port
from which Captain Cook sailed in his voyage of discovery.
of saint mida.
SOUTER POINT
The great electric light at Souter Point, which I visited
on our return voyage from the north, and a general view
of which is given in Fig. 10, is three miles below the mouth
of the river Tyne, and I reached it by carriage from South
Shields, after a hurried inspection of Sir William Armstrong's
o r d n a 11 «• e- great ordnance-works at Newcastle, with Admiral Collinson,
works of Sir Will- , .
iam Armstrong, to whom I am indebted for the permission which he had
thoughtfully
London.
permission
obtained from Sir William before leaving
Fig. 10.
Qn
View of Souter Point Light-house.
banks of the river, from the mouth to New Castle
Manufactories,
and effect of , „ „
smoke therefrom. aiKi beyond, there is an immense number of manufactories
of all kinds, and their smoke hangs over the river like a
cloud.
sea-approaches When the wind is from the westward this smoke is driven
obscured by . 1^41
smoke. over the sea-approaches to the river, obscuring, much to the
annoyance of the great number of vessels of all classes contin-
ually entering or leaving the river, not only the pier-lights
at its mouth, but the sea-coast light at Souter Point which
indicates the general position of the harbor.
SOUTER POINT LIGHTHOUSE!.
ELECTRIC LIGHT.
PLATE IX.
EUROPEAN LIGHT-HOUSE SYSTEMS. 121
Fogs on this part of the east coast of England are also Frequency of
frequent, and as they mix with the smoke, the problem of Oi
light-house illumination of the sea near the mouth of the
Tyrie is one of great difficulty.
To meet it; an electric light was constructed at Souter Lightatsouter
Point one of the
Point a few years ago, and it is without doubt one of the most powerful in
the world. •
most powerful lights in the world.
The condensed beams from the most powerful fixed and orj™e™ °f £ "a"
Hashing first-order sea-coast lights of England (with the (English.) e
Douglass four-wick burner, the illuminant being oil) are
respectively equal to 9,000 and to 111,000 candles, (ours are
much less,) while the condensed beam of the flashing electric Power of light
light at Souter Point (assuming the power of the lens, asat
calculated by Mr. Chance, to be 196 times as great as the
power of the unassisted light) is equal in power to 800,000
caudles !
That even this intense light fails to penetrate a dense fog
I know from my own experience, which I will relate furtherig,
on, and it is not surprising, since the sun itself cannot do so;
but that it meets the requirements of those intermediate
conditions of u thick weather," between fair weather and im-
penetrable fog, as well as can be asked for any possible sea-
coast light, cannot be doubted, although, considering " flex- Question of 8U.
ibility " * as well as power, I believe it yet a question which JJgJj
of the two, the gas or the electric light, may be the better.
The lens at Souter Point is of the size of those of the third
order, or 39.38 inches in diameter, and consists of a fixed-
light apparatus covering the sea-horizon, i. e., 180°, and is
surrounded by eight panels of vertical condensing-prisms,
which in their revolution give flashes at intervals of one
minute.
The lenticular apparatus is a very beautiful piece of work- ch^Tce, B?othebre
manship, and much credit has been obtained by the manu- &c°-
facturers, Chance, Brothers & Co., for their skill and in-
genuity in disposing the rays of the electric spark to the
best advantage to this locality.
The electric spark used for purposes of light-house illumi:8 ^ electric
nation differs from other sources of light in the smallnessof
its dimensions, and, within certain limits, its variability in
position.
The former feature, although requiring that the apparatus
shall be specially designed for its use, is, in the hands of alights.
competent optical engineer, a most valuable characteristic.
It is possible to direct and distribute light from a point
almost as one wishes and without waste, but the conse-
* See Haisborough gas-light.
122 EUROPEAN LIGHT-HOUSE SYSTEMS.
quences of any error in designing or executing the optical
apparatus, are even more serious and far more apparent
than when a larger source of light is used.
Accidents to re- it is a fact important to be noted that at this station, as
volvmg appara-
tus provided for. at all others in the English service, the contingency of ac-
cident to the clock-work carrying the revolving lens is pro-
vided for. A crank for turning it by hand can be attached,
and a dial placed before the keeper indicates the velocity
of revolution, so that he has no difficulty in preserving the
proper intervals between the flashes.
utilizing the A part of the light thrown to the rear (toward the land)
is taken up by an annular refracting lens surrounded by ca-
tadioptric prisms, the whole being about 15 inches in diam-
eter and forming a holophote of the sixth order, and the rays
after passing, being formed into a cylindrical beam of paral-
lel rays, impinge against a set of totally reflecting straight
pirisms, which in turn cast them at right angles, in a beam
of parallel rays, down through a vertical wooden tube, pass-
ing through a circular aperture in the floor, upon another
set of totally reflecting prisms in the room below, and they
again, turn the rays at right angles and out through a large
e r s plate-glass window upon some dangers southward of the
point, which are called " The Mill Rock," " Hendon Rock,"
and uThe White Stones." (See Plate IX, which is a* chart
showing Souter Point and its vicinity.)
The window through which this borrowed light passes is
divided vertically into two parts, the one on the western or
land-side being red and the other white ; the line of divis-
ion being produced over the sea gives a "red cut," the
utility of which will be understood from the following sail-
ing-directions, taken from the British light-house list :
Sailing direc- " SOUTER POINT.— T/itf main light is electric and flashes
every minute. A fixed light, also electric, is shown 21 feet
below the flashing light, and shows white between the bearings
of N. by W. and N. J E., and red between N. £ E. and N.
by E. f E. When the fixed white light is seen, vessels will be
in line of Mill Rock and Cape Carr 'Point, and when it chancjes
to red, in that of Whitburn Stile, Hendon Rock, and White
Stones."
Plate x. Plate X shows a plan of the lower light-room and details
of the window through which the " red cut " is made, a in
the plan showing the position of the lower refracting prisms.
Plate XL The engine-room, a plan of which is shown in Plate XI,
with its accessories, (including fuel-rooms for the storing of
coke, of which about 100 tons are used annually,) and the
dwellings of the keepers form a large quadrangle, (see Plates
SCALE TOR PL AN
SECTION OF WINDOW A.
SCALEroa DETAILS.
SOUTER POINT LIGHTHOUSE.
ELECTRIC LIGHT.
PLAN OF MACHINE-ROOM.
PLATE XI
EUROPEAN LIGHT-HOUSE SYSTEMS. 123
XII and XIII,) the former being on the land-side, while, piatesxiiand
toward the east or seaward, is the tower, which is detached .
from the rest of the establishment, except that communica-
tion is had by a covered way one story high.
The machinery for generating the electric current is simi- Machinery.
lar to that at South Foreland.
Two rotary magneto-electric machines of Professor Holmes' Magneto-eiec-
. , tricmachinesand
patent are driven by two 3 horse-power engines which can engine,
be worked up to 6 horse-power each.
Each machine consists of eight radial frames, to each of construction of
which are attached 36 magnets, making 288 in all, and the the machine8-
poles are alternately pointed toward and from the axis of
the machine.
A shaft driven by the engine, revolves a series of cylinders The magnets.
composed of helices of wire, past the magnets, which pro-
duce the alternately positive and negative currents. These
currents are collected by the wires passing up the tower to dl£™Jrent8 pro"
the electric lamp within the lens.
The number of revolutions made by each machine per Number of rev-
jrvrt T i -i -i -i i olutious per miri-
imnute is 400, and as 16 sparks are produced by each mag- ute and conse-
net at each revolution, the number of sparks at the carbon sparks™"
points of the lamp is 6,400 per minute, when one machine
only is in operation, as is the case in fair weather, and 12,800
per minute when both machines are at work. These sparks
are formed 'so rapidly that the eye does not separate them,
and the result is a continuous beam of light, so dazzling,
that the eye of a person within the lantern cannot rest upon
it for an instant, without intense pain.
To insulate the shaft of the machine which conducts the insulation of
electric current to the wires, it is encased in ebony-wood
journals, and where the wires pass through the wall of the
engine-room there is a coupling-box so arranged that, by a
single motion, they can be connected or disconnected, and
the current from one machine or two can be turned on to
the lamp at pleasure.
The electric lamp, as at South Foreland, consists mainly Electric lamp.
of two carbon points, each about ten inches long by one-
half an inch square in section, placed end to end in a ver-
tical position, and the automatic machines called regulators,
feed the points toward each other as last as they are con-
sumed, which is at the rate of one inch per hour each.
An oil-lamp is placed under the electric lamp, and is on-iampforuse
always filled and ready to be substituted in case of accident den?80
to the latter, or to the machinery ; but I did not learn that
a necessity for its use had ever arisen.
124
EUROPEAN LIGHT-HOUSE SYSTEMS.
Plate XIV and Fig. 11 illustrate the disposition of the
different parts of the lenticular apparatus at Souter Point.
In the former a is the focus ; a' the electric lamp ; a" a"
the carbon pencils ; b the holophote; c the upper totally
reflecting prisms ; d d the fixed dioptric apparatus ; e e the
revolving frame of flash-panels ; // revolving gearing; g
the removable bed-plate ; h the burner of the oil-lamp 5 'i
telescopic tubes for the supply of oil and the overflow, for
use if the oil-lamp should be substituted at any time for the
electric lamp • I the oil-reservoir; m m the oil-supply pipe ;
n cylindrical shaft for transmission of the beam of reflected
light to the lower light-room 5 o the lower reflecting prisms ;
pp the window of the lower light-room; g a gallery used
when cleaning the sash of the window.
Tig. 11.
Plan of lens and lantern, Souter Point.
In the figure a is the focus ; b the holophote ; c c the upper
reflecting prisms ; d d d the fixed dioptric apparatus ; e e e
the flash-panels. The dotted circle under c c shows in plan
the shaft for transmitting the beam of reflected light to the
lower light-room.
The tower at Souter Point, shown in Plate XV, is built
like most of the towers I saw in England, being a shell of
brick- work into which the steps are let at the outer end
only, and with landings at the windows.
* t
< I
o
n
z
n
>
r
•D
r
n
r r
II
H .
n
SOUTER POINT LIGHTHOUSE
ELECTRIC LIGHT.
PLATE XIII,
GROUND^ PLAN.
IT. Bret-Room*.
tf. tp. fln-ft-fti {.'wridors.
o. o.JZarthr Closeif.
p. Coke-Store .
q.JZoilers.
i.i. XcnlUriss.
lp_ A ' O fO 20
SCALE.
t.t.Wo?>hshops.
v. Y.Worhbenches.
o Tja&it.
EUROPEAN LIGHT-HOUSE SYSTEMS. 125
The watch-room floor is of iron and supported upon a watch-room.
system of radiating and concentric beams. The watch-
room is fitted up with supplies for use in the lantern, viz,
oil, burners, and chimneys, and skins and cloths for clean-
ing the metal- work and glass of the lantern and lens.
The lantern is of the size heretofore described, viz, 14 Lantern.
feet in diameter, and it has diagonal sash-bars of steel.
On the cliff in front of the tower is a Holmes fog-horn, Fog-horn.
sounded in foggy weather by means of the engine for driv-
ing the magneto-electric machines. An ingenious contriv-
ance of the inventor makes the down-strokes of the plungers
of the air-pump slow and the up-strokes quick. This
done by means of three eccentric cog-wheels, the middle pump-
one (the driving-wheel) of which gives motion to the two
others, to which are connected the shafts of the pumps.
The cost of the station is given as follows : cost of station
with revolving
Building- works £7, 150 $35, 750 electric »ght.
Lantern, dioptric apparatus, &c 3, 436 17, 180
Electric apparatus, machinery, &c 4, 100 20, 500
Miscellaneous 462 2,310
15, 148 75, 740
Deducting about £750 ($3,750) on account of difference
in cost of revolving and fixed dioptric apparatus, and also
the cost of revolving machinery, the above sum would indi-
cate the approximate cost in England of a fixed magneto-
electric light.
Electric lights, being considered more important than The best keep-
others, receive the preference in appointment of keepers, Slfflciights.01
and the most competent are appointed for these stations,
their salaries exceeding that of keepers of their grade at
other lights 10 per cent.
Each electric light-station is in the immediate charge of a r?"f ^i kree !er
principal keeper, who is called an engineer.
At South Foreland, where there are two lights, six assist- ke?pe£ bat reiecf
ants are allowed ; at Dungeness, five ; and at Souter Point, tric light8-
four.
At these lights the engineer has sole charge, and is ustati°? in
charge of the en-
responsible for the premises, property, and stores, as well gineer.
as for the proper service and efficiency of the light. When
he is absent the senior assistant takes his place. He is not
required to keep watch, but must visit the lantern and
engine-room at various times during the night, besides the
regular visits at the end of each four-hour watch; and
must always be present in the engine-room when preparing
for lighting.
126 EUROPEAN LIGHT-HOUSE SYSTEMS.
watches of The assistants take equal watches of four hours each, one
keepers at elec- , , . -. . , . ,
trie lights. in the engine-room and one in the lantern.
boFie?sincs and ^^e engines an(l boilers are worked alternately, one each
week. Steam is to be up in one boiler (the other boiler
being filled and the fire ready for lighting) and the mag-
neto-electric machines ready for starting five minutes before
nd°f extin " sunse^ ^ne lamP is lighted at sunset and extinguished
at sunrise.
In case of accident to any part of the electric apparatus.
the oil-lamps must be immediately substituted for the electric
lamps, and to keep them in perfect order, it is required that
they be lighted and kept perfectly in focus for one hour
(during the day) once a week.
observation of After leaving the Tyne at night we stood off from Souter
lt- Point to observe the light from the sea, and it certainly
surpassed in brilliancy any I have ever seen, being so
bright that at a distance of several miles well-defined shad-
ows were cast upon the deck'of the Vestal.
effectso7thl red We afterward took the pinnace of the Vestal and steamed
cut into the white and the red lights from the low light, and
across the "red cut" several times andin different directions.
We found it quite well defined, so that no vessel in a clear
night when observing the sailing-directions could get into
the dangers which the low lights are designed to point out.
Admiral Collinson had given directions to have the fog-
trumpet sounded when the keepers should observe the Vestal,
but we were probably too far off while observing the light
from the sea, for we did not hear it.
Light obscured As before observed, we visited this light on our return
smoke6 ( a voyage from the north, but it had happened that, on going
to the north, it being thick and rainy, a dense cloud of fog
and smoke shut down over the sea before we arrived off
Souter Point, and we ran in toward the land, passing the
light as we supposed within three miles, but did not see it.
Finding our position after reaching the mouth of the
Tyne, we ran back toward Souter, and in, as far as was
thought safe on account of the dangerous rocks in the vicin-
impossibiiityity, but still could not see the light. This confirmed the
fog byTnyriightg opinion of the Elder Brethren as well as of oursel ves, that
there is no light which will penetrate a fog, and all that is
possible in light-house illumination is to make light suffi-
ciently powerful to be depended upon in all sorts of thick
weather up to the impenetrable limit.
utility of low There can be no doubt of the utility of the low light and
h-ins and red the u re(j cut » in pointing out dangers within range of a
SOUTER POINT LIGHTHOUSE.
ELECTRIC LIGHT.
PLATE XIV
(0
o
r *
5 "*
22
o
c*
Fl
EUROPEAN LIGHT-HOUSE SYSTEMS. 127
light-house. I will describe a more marked case of their
application at Coquet Island.
Another application of the use of borrowed light has sug- Suggestion as
gested itself to me. It is this: Our sea-coast lights are often lights on our own
from 150 to 200 feet above the sea, and it frequently hap- c'
pens, particularly on our Pacific coast, that a fog will hang
over the sea and shore low enough to envelop a light at
this elevation, and yet it remains clear below and at the
level of the sea.
Where the tower is not surrounded by water and there is Method to be
a laud-side, as is almost 'always the case, a part of the light empi°:
thrown to the rear or landward can be taken up, as at Sou-
ter, and thrown by means of totally reflecting prisms through
a tube passing down the tower to a lens placed in a salient
lantern at the proper distance, say 15 or 20 feet above the
foot of the tower.
In my description of lights on the coast of Wales will be
found an account of a separate low light for foggy weather
in actual use.
COQUET.
This interesting light-house is on Coquet Island, off the Position.
coast of Northumberland, and is of the first order, dioptric,
the lens covering about 270° of the horizon.
A vertical pane of red glass attached to the lanteru cov- Red light.
ers an area to the northward with red light, and the narrow
Coquet Eoads inside the island are illuminated by the lamp
alone, unassisted by lenticular apparatus.
Areas both to the northward and southward are purposely Areas shut off
shut off from all light from the lens, by means of opaque fr(
panels in the lantern, the object being to warn vessels of
their proximity to danger when the light is lost sight of.
The height of the focal plane of this light above the sea Height of foca
is 83 feet. plane-
.Below the watch-room is a lower light-room, with a large Lower light-
plate- glass window looking to the southward, and, on theroom'
opposite side of the room, near the middle of the wall, 28
feet below the focal plane of the main light, is a catoptric
apparatus, consisting of three reflectors provided with lamps
having red chimneys.
The jambs of the window limit the red rays emanating: Limitation of
« . ° red rays.
from these lamps, and mariners are warned to use great
caution in approaching the shore after they get into the red
light.
For the further purpose of marking the position of an im- dn^d cu * pr
portant buoy, a red "cut" is produced by means of a fourth
128
EUROPEAN LIGHT-HOUSE SYSTEMS.
reflector placed near the northwest corner of the room, which
throws a beam of white light through the red, the cut being
made at the- edge of the ruby-glass, with which a part of the
window is glazed. This red cut intensifies the cut produced
by the interception by the east jamb of the window of the
rays from the three red-light reflectors.
Fig. 12.
Low-light room, Coquet island.
Figure 12 shows the arrangement of light in the lower
light-room ; a is the single reflector for white light ; &, the
three reflectors for red light, placed one over the other, but
with their axes slightly divergent in plan ; c, a vertical
strip of red glass, the western edge of which divides the light
from a into red and white lights ; $, the eastern window-
jamb limiting the red light from b-, «, the sector of white
light, and {3 the sector of red light 5 a c and b d are parallel.
The purpose of the ingenious arrangement of lights in
the lower light-room will be better understood by an in-
spection of the chart in Plate XVI, and from the following
sailing-directions :
Sailing-air ec- COQUET ISLAND. — The upper light, wliite, is visible seaward
between the bearings from the sea of S. by W . f TT., and.N. f
K; and red from 8. by W. f W. to S. by W. % W., to cover
the Bulmer Bush and Bulmer Stile rocks.
"A dim white light from the naked lamp of the apparatus
is shown between the bearings S. and N. E. f N". to cover the
anchorage inside the island.
tions.
PLATE XVI.
EUROPEAN LIGHT-HOUSE SYSTEMS. 129
"A second light, twenty-eight feet below the main light, is
shown from the same tower. It is white beticeen the bearings
from the sea of N. by W. f W. and N. J W., to guard the shoal
off Rauxley Point, and red from N. % W. to N. by E.$E., to
cover the Bondicar Bush shoal.
a When the upper light is lost sight of westward of N. f E.,
the line of Hauxley Point and Bondicar Bush will be passed,
and while in the low red light great caution is necessary in
approaching the shore" Diviaion of the
sea-area around
It will be observed that the sea around Coquet Island is tho light into
divided into eight distinct areas, each of which is easily e1'
recognizable by an inspection of the lights ; that is to say, in
going from the northward round by the eastward and south-
ward, the following changes are seen :
Bearings of tlie light-house. Appearances of the lights.
From S. 21° W. to N. 21° W.
From N. 21° W. to N. 6° W.
From N. GO W. to N. 7° E.
From N. 7° E. to N. 15J° E.
From N. 15£° E. to N. 38° E.
From N. 38° E. to S. 1° E.
From S. 1°- E. to S. 17° W.
From S. 17° W. to S. 21° W.
Main light (only) white.
Both the high and low lights,
white.
The high light white, the low
light red.
The lower light (only) red.
No light.
Dim high light unassisted
by lens, white.
No light.
The high light (only) red.
Arrangem e n t
, , • _ of lights the best
The mam light could not have been arranged to warn the that could be had.
mariner of the near dangers, as the low light so success-
fully does, since the former must throw its light uniformly
over the sea and many miles farther to the southward be-
yond the dangerous rocks and reefs. Tower and
The tower and dwelling at Coquet are built of stone and dwelling-
are very picturesque, the station having been built upon
the remains of a Norman monastery. Buoy-depot.
Adjoining the light-house is a substantial buoy-depot,
and a well-built wharf is provided with a traveling-crane
for loading and unloading.
The lights on this part of the coast are under the super- Morton-
intendence of Mr. Morton, whose polite attentions I desire
to acknowledge.
S. Ex. 54 9
130 EUROPEAN LIGHT-HOUSE SYSTEMS.
observing While lying in Coquet Koads I went at night with Admiral
th^seaatnight^Colliusou in the steam-pinnace to observe the red cut of
the low light ; its utility, which had been explained to ine
in theory, I found fully confirmed in practice.
visit to castle j am aiso under obligations to the admiral for an oppor-
01 Warkworth.
tunity of visiting with him one of the most interesting
places in England, the ruins of the once magnificent Castle
of Warkworth, the home of the Percys, which is a few miles
from the landing-place opposite Coquet Island.
INNER FARNE ISLAND.
Lights form a There are two lights on the Inner Fame, which is off the
coast of Northumberland, and they form a range or lead.
characteristic The main light is catoptric and revolving, there being seven
° o?Tdw ifgit. reflectors, (one on each face.) The low light is about 200
yards northwest from the main light, and contains a single
fixed reflector.
Keeperof main The keeper of the main light watches the other by means
light watches the
low light; meth- of a small reflector, which catches a little of the ligh tof the
latter and throws it back toward the lantern of the main
light through an aperture in the smaller tower.
chimneys. The only peculiarity to be observed at this station was
the chimneys of the reflector-lamps, which had no shoulders,
but were conical from top to bottom, with a large flare.
THE LONGSTONE.
Themostnorth- The Outer Fame or Longstone light-house is, with the
ern of North Sea ,. _ .. . ,. . , , _. . . , , . ,. _
lights. exception of a small pier-light at Berwick, at the mouth of
the Tweed, the most northern of the North Sea lights of
England, and is in view of the light on St. Abb's Head, the
first of the Scottish lights.
Construction. j^ js a TOG^ light-house of the peculiar construction shown
in Plate XVII, the tower and dwellings being surrounded
by high walls to protect them from the sea, which frequently
rolls with great violence over the rock, which is long and
narrow.
LCDS. A new first-order revolving lens, made by Chance Broth-
ers & Co., has recently been placed in the tower, and the
entire station has been repaired and refitted, the mechanics
being still at work at the time of my visit.
Light seen While at Coquet Island I saw this light very distinctly
the deck of the Vestal, say 10 feet above the sea, at a
£. °f en distance of twenty miles, which was remarkable, as the
focal plane is but 85 feet above the sea.
.Plate XYIL
*
THE LONGSTONE LIGHT-HOUSE.
EUROPEAN LIGHT-HOUSE SYSTEMS. 131
There is only the ordinary number of keepers (two) at Keepers.
this station, but they are supplied with provisions from the
mainland and but rarely leave the rock.
This light-house is interesting as having been the home of The home ot
Grace Darling, the daughter of a former keeper, and to Grace Darling'
whom owed their rescue the nine out of the sixty-three who
were on the Forfarshire when she struck the "Hawker
Kock," near the Longstoue, on the 5th of September, 1838.
The keepers had much pride in showing us the bed-closet
occupied by the heroine and the window through which she
first saw the wreck. A beautiful tomb is erected in her Tomb of Grace
memory, at Bamborough Castle, near by on the mainland. Darlm*
The foregoing comprises the notes of my journey among Thank8to Ad
the lights of the North Sea, and I must, in concluding my
account of it, express my thanks to Admiral Oollinson and ler-
Captain Weller for their unremitting efforts to make it for
me a journey of pleasure as well as of profit.
The Vestal, in which this cruise was made, is a handsome Description of
sea-going side- wheel steamer, about the size of our supply -
steamer Fern, and is used for conveying oil and other sup-
plies to the light-houses, and for purposes of inspection.
A yearly inspection of the light-stations is made by some Yearly
of the Elder Brethren 5 at other times the superintendent in
charge of each district inspects the stations and causes the
necessary repairs to be made.
The Trinity House has several of these steam tenders, or
"yachts," as they are called, each of them carrying a steam
pinnace or launch outboard.
The weight being too heavy for the davits, two swinging
brackets were placed under the bottom of the launch and
stepped upon the rail of the steamer. These supports can
be raised or lowered by means of a screw-thread and a
stationary nut in the rail.
These launches are of much utility in landing stores and use of the pin.
towing the other boats, (of which the Vestal carries four,) na
and they steam from six to eight knots an hour. In going
to beaches or rocks the launch is always accompanied by a Dingey carried
by the pinnace.
dingey ; this, as does each of the other boats, carries on its
thwarts a gang-plank, which is made with a triangular cut
at one end, to be hung over and against the stem of the
boat. These gang-planks, which are battened on the upper Gang-planks,
surface, and are about 10 feet long, are found to be very
useful.
The Vestal has no house on deck except a small one over House on deck.
132 EUROPEAN LIGHT-HOUSE SYSTEMS.
the main companion-way to the saloon, and another over
the galley between the paddle-boxes.
Having landed from the Yestal at Harwich, on the 19th
Dinner at the of Jane, we returned to London by rail, and I had the
Trinity House in
honor of the pleasure of attending an annual dinner given at the Trinity
Younger Breth- L
ren. House, according to custom, in honor of the Younger
Brethren.
There were about one hundred persons present, and the
th^Lfhfnonse ver^ complimentary allusions made by Sir Frederick Arrow,
uniterddstate8the Deputy Master of the Trinity House, in the course of the
after-dinner speeches, in reference to the Light:House Estab-
lishment of the United States, and toour Chairman, Professor
Henry, in particular, were received with enthusiasm.
On the 22d I went down to Portsmouth by rail, with Sir
Naval review Frederick, to witness the grand naval review at Spithead in
in honor of the , ,^1 i /» T^ • « • i ,11
shah of Persia, honor of the Shah of Persia, which was to take place on the
23d, after which I was to embark on the Vestal for an in-
spection of the lights on the south and southwest coasts of
England.
Sir Frederick was kind enough to invite me to accompany
him on board the Galatea, a fine large steam-yacht belonging
to the Trinity House, which with the Eoyal Yacht Alberta
formed the escort to the Yictoria and Albert, which carried
the Shah, his Eoyal Highness the Prince of Wales, and other
members of the royal family through the lines, so that I had an
excellent opportunity of seeing this magnificent pageant,
which comprised nearly all the celebrated iron-clads of
Great Britain, including the Agincourt, the Hercules, the
Devastation, and eight others, and surpassed even the re-
view of Sir Charles Napier's Baltic fleet during the Crimean
war, the only one in history comparable with it.
joining the On the 24th I left the Galatea and joined the Yestal to
accompany Captain Webb, of the Elder Brethren, on the pro-
posed cruise of inspection.
On this journey we had the pleasure of the society of an
agreeable guest of the captain, Colonel Sim, of the Eoyal
Engineers, who remained with us till we left the yacht at Saint
Ives, on the west coast of Cornwall.
Detention a t We steamed over to Cowes, on the Isle of Wight, where
we were detained a day by a severe storm, but the deten-
tion afforded me an opportunity of inspecting the Trinity
House depot in the harbor, the light-house of. Saint Cath-
erine on the outer side of the island, and a drive to Osborne
House.
Trinity House The depot is very complete, and is fitted up with every
depot at cowes. conveuience for the^supply of the lights of the district.
EUROPEAN LIGHT-HOUSE SYSTEMS. 133
Tbe buildings and landing-place are unusually fine, the
latter being used by the Queen during her residence on the
island.
ST. CATHERINE.
This station is on the extreme point of the southern or Position,
sea-face of the Isle of Wight, and we reached it by carriage
from Cowes, crossing the entire breadth of the island, the
topographical features of which are everywhere beautifully
diversified.
The tower, which is 122 feet high, and carries a fixed Tower,
light of the first order, is octagonal in form, and is, as are
all the buildings of the station, of a pleasing design, being
built of stone in the crenelated style, and in the most thor-
ough manner.
Unfortunately there is occurring here what I have ob- Gradual mov-
served before only on the coast of California, i. e., the entire suf face ^f^tS
surface of the side of the great cliff which rises behind thelai
light-house and the plateau on which it stands are grad-
ually moving toward the sea, sliding upon some stratum
below, carrying the fine tower, which is already slightly out
of the vertical, with it; and unless some means are taken
to prevent further motion of the tower much trouble is
anticipated.
Below the main floor of this tower is the oil-cellar, a cir- oa-ceiiar.
cular room, having the one hundred gallon oil-cans (or cis-
terns as they are termed in England) ranged around the
wall.
There is an opening in the middle of the floor above this Filling oil-
cellar through which, when oil is being delivered at the
station, is passed a tube about 4 inches in diameter, which
is bent below the arch, so that it can be turned into any of
the cans, while at the upper end and above the floor is fitted
a large funnel, into which the oil is poured, so that it is not
necessary to carry it below the main floor of the tower.
(See Fig. 13.)
This is a fog-signal station, and on the point in front of Engine for fog-
the light-house is the engine-house, containing an Ericsson Blg
hot-air engine of 24-inch cylinder, 4 horse-power, and run-
ning under 12 pounds of pressure.
The trumpet rises through the iron roof, and its face, Fog-signai.
which is vertical, turns through the sea-arc of the hori-
zon 215°.
AvS an instance of the effect of projecting points which Effect of pro-
produce sound-shadows that very often interfere with the Jroduf ing sound8
utility of fog-signals, I will mention that on the night be-8hadowa
134
EUROPEAN LIGHT-HOUSE SYSTEMS.
fore our visit to Saint Catherine a large vessel had gone
ashore in a bay three miles to the westward, the night being
foggy and an intervening point preventing the sound of the
signal from covering that part of the shore. There are
three keepers at this station.
Fig. 13.
THE NEEDLES.
Location and This light-house is situated on an island at the western
characteristics. .. „ ., T , ,, -rrr -, . -, •, -, r> i
extremity of the Isle of Wight, and has a first-order fixed
dioptric apparatus, producing two red and two white sectors
of illumination.
Red cuts. The following, from the British light-house list, shows
another application of the system of ared cuts," of which I
have before made mention, and of which there are, as will
be observed, many examples in the English light-houses :
" NEEDLES LIGHT. — Red when bearing from N. W. J N.
(round northerly) to E. White from E. to E. 8. E. ; red from
E. S. E. (round southerly] to 8. W. by W. ; and ivhite from
8. W. by W. to S. W. by W. $ W. The white light shows in
the direction of the Needles Channel, its southern limit bearing JE.
passes one and a half miles S. of Durlston Head, and about a
EUROPEAN LIGHT-HOUSE SYSTEMS. 135
cable 8. of outer part of Bridge Reef. Its northern limit, bear-
ing E. S. E.j passes two cables south of Dolphin Banlc, and the
S. W. buoy of the Shingles.
"The ray of u-hiie light between the bearings of S. W. by W.
and S. W. by W. J W. clears Warden ledge."
We did not visit this light, but as we passed it early in
the morning it shone brilliantly and gave us a good illus-
tration of the system of pointing out dangers by "red
cuts."
THE BILL OF PORTLAND.
We passed in view of these two fine light-houses on the
coast of Dorsetshire without stopping.
They were built in 1716, and in 1788 the coal-fires which .^ate of build-
burned on their summits were extinguished and oil first
came into use.
They are about five hundred yards apart, and form a range
or lead between the Race and Shambles.
THE START.
The Start light-house is a bold headland on the coast of
Devonshire, and when I visited it there were extensive Repairs.
renovations going on, including the placing of one of the
latest first-order lanterns, of Mr. Douglass's design — 13 feet
inside diameter — in lieu of the old one.
The light is revolving, and the difficulty of making this change of iau-
tern without ex-
change without extinguishing the light was overcome by the gnguWrtng the
use of a ship's revolving catoptric apparatus of the same
interval, building the new lantern up around it.
This lantern has diagonal bars of steel formed of two Diagonal sash-
thicknesses of J inch each, so the bar, when finished, is 3
inches by 1 inch.
The glass (J inch thick) is not set in a rebate, but the Setting of the
lozenge- shaped panes abut against each other outside the s '
bars, and the joints are covered by strips of brass fastened
by screw-bolts, through the glass and into the steel bars.
The cost of these lanterns is about £1,700, ($8,500.) Cost of lantern.
There is a lower light-room, from which a single reflector Lower light-
throws a fixed light over a danger called " The Skerries."
There is a fog-bell at this station, weighing thirty-five
hundred pounds, and struck on the inside by machinery. It
strikes five hours without winding up the weights, an opera-
tion requiring fifteen minutes, during which the striking is
interrupted.
EUROPEAN LIGHT-HOUSE SYSTEMS.
Resemblance to The resemblance of Start Point to Point Bonita, at the
entrance of the Golden Gate of San Francisco, is remark-
able.
THE EDDYSTONE.
view of the On the morning of the 26th of June we came in sight of
the light-house which, more than any other extant, is known
throughout the world as a splendid proof of the ability of
man to overcome the force of the sea — the famous Eddy-
stone, which lies off the coast of Devonshire.
sweii of the sea There was a heavy swell from the Atlantic, and as the
preventsianding. yesta| neared the light-house we were disappointed to see
the waves running high up the tower, and the keepers' signal
from the gallery at its summit that a landing was impracti-
cable ] but I was much gratified at having even such an
opportunity of seeing this historical work.
Appearance. Neither in height nor in appearance is it the equal of
either of the modern light houses The Wolf or The Long-
ships, off Land's End, which I afterward visited, yet I could
not but feel a thrill of admiration as I gazed at this grand
old tower which has so successfully battled with the sea for
one hundred and fifteen years.
Date of build- The first light-house on the Eddystone was commenced in
t?ouseeonrthe* Ed- 1G96, finished in 1698, and was destroyed in a terrible storm
in 1703. Not a vestige of the building remained, and neither
its keepers nor Henry Winstauley, its builder, who had
wished to be in his light-house "in the greatest storm that
ever blew under the face of heaven," were heard of after-
ward.
Date of build- The second light-house was built by John Eudyerd. It
was lighted in 1709, and destroyed by fire in 1755.
Date of build- The builder of the present light-house was John Smeaton,
on?. l a who commenced the work in 1756, and finished it in 1759.
Account of Of the construction he has given a most interesting nar-
rative, or, as he styles it in the dedication to his King, " a
plain account of a plain and simple building that has never-
theless been acknowledged to be in itself curious, difficult, and
useful," which clearly exhibits the industry, perseverance,
and genius of one of the most remarkable of men. His
plan was entirely different from those of his predecessors,
he having conceived the idea that a light-house in a posi-
tion like this, in order to withstand the sea, must depend
upon its weight.
Method of join- He therefore built it of stone, dovetailing the joints, as
ing the stones. shown iu plate XXI, so that no stone can be moved with-
out displacing the others, and his work has furnished a
model upon which all rock light-houses built from Smeaton's
Plate lYffl.
THE EDDYSTONE LIGHT-HOUSE.
EUROPEAN LIGHT-HOUSE SYSTEMS.
137
time to the present have been constructed, except as regards
some of the details, which have been modified in some de-
gree by their respective engineers.
The science of illumination, as applied to the Eddystone, po*4Vi£st u^el"
was far behind the science of construction, and while
Smeaton sprang at once from the prejudice of his time to a
full conception of the true principles which should govern
the construction of a work of this character, it remained
lighted for many years as at first, by "twenty-four candles
burning at once. Jive ichereof iceighed two pounds.77*
Reflectors were not introduced -until early in the present Reflectors used.
century, and in 1845 these in turn gave way to a second-
order Fresuel lens, (fixed,) the beam from which, with its Fresnei lens.
Douglass burner, is equal to 4,650 candles. This was the
first catadioptric apparatus ever constructed.
SAINT ANTHONY.
This is an old station on the coast of Cornwall, standing Position.
on a rugged promontory projecting into the bay which
leads into the harbor of Falmouth.
The tower is square, and contains the dwelling for the Tower.
principal keeper and his family, the assistant occupying a
cottage connected with the tower by a covered way.
The apparatus is catoptric, and is composed of eight re- Apparatus.
Sectors, one on each face of the revolving frame.
There is a bell, struck by machinery, but quite unlike the
others we had seen, and, indeed, there appears to be no
uniformity in the bell-machinery of the English service, as
many being struck by the hammer on the inner as on the
outer side.
A single reflector is placed in the living-room of the prin-
cipal keeper, and shows through a square window a fixed
white light to guide clear of some dangerous rocks, called
4 'The Manacles."
PLYMOUTH.
This light-house, which corresponds to the general char-
acter of "rock" light-houses, is placed on the end of the
fine breakwater which protects the harbor of Plymouth,
and is one of the most elaborate pieces of stone-work I
have ever seen. The material of which it is built is a beau- Material of
tiful granite from Penrhyn, in Wales, and on the interior tovver>
the immense expense of the construction is shown by the
exquisite finish, almost polish, of the surfaces. The floors, Beauty of fin-
ceilings, partitions, and walls are all of granite, and no lin- 1S
ing of any kind is used.
Low light.
* Smeaton's Narrative of the building of the Eddystone Light-house.
138
EUROPEAN LIGHT-HOUSE SYSTEMS.
Strength of the
structure.
Arrange me n t
of rooms.
Characteristics
of the light.
Red light, how
produced.
Method adopt-
ed to more sharp-
ly define the
" cuts."
This tower is exposed to the heavy seas which roll over
the breakwater, and for a distance of 10 feet from the bot-
tom it is a solid mass of masonry. Its entrance is through
a heavy gun-metal door, sliding upon rollers at top and
bottom.
The lower floor contains the siore-sooms ; the second floor
the oil-rooms; the third floor the kitchen and living-rooms;
the fourth the bed-room, and the fifth the service-room.
All the doors and window-frames are of gun-metal.
A small segment of a fifth-order dioptric apparatus in
the watch-room throws a beam of leading white light
through a small window upon a buoy and the fairway, the
beam being limited by placing in front of the lens a me-
tallic case in which there is a narrow slit about 2J inches
wide.
The main light shows white within the anchorage and red
to seaward.
The red light is produced by surrounding the lamp, (one
of the second order,) except for the small arc covering the
anchorage, with a red cylindrical glass about 9 inches in
diameter.
To more sharply define the "cut" between the red and
white light, narrow vertical strips of red glass are placed
opposite the edges of the segments of this cylindrical glass
and outside the lens.
This mode of producing red light by means of a cylinder
around the lamp is different from any I saw elsewhere, and
is shown in Fig. 14, in which &, a', represent the red shade,
c the lamp, and a the sector of white light.
Fig. 14.
Red Cut, Plymouth Breakwater.
Libraries. As before observed, the corporation of Trinity House fur-
nishes its keepers with books by means of circulating libra-
ries, and there are also fixed libraries at the station. The
latter contains bibles, prayer-books, dictionaries, religious
EUROPEAN LIGHT-HOUSE SYSTEMS. 139
works, and others of permanent interest or value. The cir-
culating libraries are carried in neat, strong boxe,«, about 12
inches square by 18 inches long, and contain bound vol-
umes of Punch, illustrated periodicals, novels, and other
light reading. There are from eight to ten books in each
box ; these boxes, which are numbered and charged to the
principal keeper of the station where left, are exchanged on
the visits of the supply-vessel.
The keepers are uniformed by the Trinity House, one suit uniform of
of clothing being supplied annually. At rock light-houses
they are also supplied with great-coats.
They are required to wear their uniforms on Sundays and
holidays, when they go to the villages or to church ; also
whenever any of the officers of the Corporation visit the
station.
The keepers are a bright and intelligent class of men, who ^character of
seem well instructed in their duties. They are neat, trim
in their appearance, and manifest pride in the stations.
Flag-staffs at light-stations are universal, and whenever Mag -staffs
the light-house has a land-side the mast is stepped on the
lantern-gallery.
The Trinity House flag is displayed on Sundays and holi- Trinity House
i -. , , , m • -, flag displayed.
days, and when national vessels are passing, or the Trinity
House yachts are at the stations.
THE LIZARD.
This is alarge establishment consisting of two towers, con- Establishment.
nected by a long building occupied by the keepers and their
families, and they also contain the oil-cellars and store-rooms
of the station.
The towers, the focal planes of which are 229 and 232 er^eigbt of ' tow"
feet respectively above the sea, were first illuminated by
coal-fires on the tops in 1752. Oil was substituted in 1812, u c°al-firc8 firsr
and the original lanterns and first- order catoptric apparatus on substituted,
are still in use.
The lanterns are excessively heavy, but both they and the ^1^™* and
reflectors are good examples of the light-house engineering
of the beginning of this century. Although they are sixty-
two years old and have been subjected to the thorough
burnishing which the English light-keepers certainly have
not failed to perform faithfully every day of that long period,
the reflectors are to all appearances as bright and service-
able as when new. Originally, reflectors were made by Orifrina] meth.
beating the silver into parabolic form, and they were no ° °
doubt better than can be obtained at the present day.
140 EUEOPEAN LIGHT-HOUSE SYSTEMS.
characteristics The lights are fixed, and the apparatus consists of nine-
teen 21-inch reflectors in each tower, each lighted by an
Argand burner.
importance of Lizard Point is a bold headland on the coast of Cornwall,
projecting far beyond the general trend of the southwest
coast of England, and Captain Webb informed me that as it
is the first land-fall of most of the oversea commerce which
enters the English Channel, it is one of the most useful light-
stations of the kingdom ; also that the brilliancy of its lights
Satisfactory is often praised by mariners, and no desire for a change has
been expressed, for which reason the Trinity House does
not propose to make any, certainly at present, though it is
a rule that when extensive repairs are necessary at large
stations, catoptric apparatus, of which there are but few exam-
ples remaining, is changed for dioptric.
superiority of The English have no doubt of the great superiority of the
tusptr a latter, and its very great economy in consumption of oil, but
when small areas are to be lighted, as in case of range or
leading lights, reflectors are in many instances used instead
Catoptric appa-
ratus, when used, of more expensive lenses of the smaller orders.
Excellent con- ^ne station was in excellent condition, and maintained by
dition of station, three keepers, the principal of whom had been forty years
in the service, being a large portion of the time at the light-
house at Gibraltar, which belongs to the Corporation of
Trinity House.
FO to There are dangerous reefs and rocks far out in front of
ttie Lizard, and it is the intention to place a fog-gun here;
the necessity of some powerful signal is very apparent.
THE WOLF.
Position. Ten miles to the southwest of Laud's End is one of the
latest achievements of modern light-house engineering, The
Wolf Eock light-house, a view of which is shown in Plate
XIX.
Date of build- It was commenced in 1862, under the direction of the
iug- father of Mr. James K Douglass, the present engineer of
the Trinity House, and finished by the latter in 1869.
Exposed Posi- The rock, which is 17 feet above low tide, (the tide rising
ock' 19 feet,) has twenty fathoms of water around it; is exposed
to the full force of the waves of the Atlantic, and was for
centuries the dread of the mariner; now its very distance
from the shore adds to its value as a site for a light-house
to guide into the English Channel ; but there is probably
no position whose occupation has required more skill and
perseverance, or more courage in overcoming difficulties and
dangers.
Piate XIX.
THE WOLF ROCK LIGHT-HOUSE.
EUROPEAN LIGHT-HOUSE SYSTEMS. 141
The position of this light-house is shown in Plate XX, Chart showing
which is a chart taken from Mr. D ouglass's interesting paper, p°
concerning the history and the peculiarities of construction
of this interesting work ; to the same paper I am indebted
for many of the data concerning it which 1 have embodied
herein.
In the year 1795 a day -beacon was erected here, and at Day-be a con a
A. . ' placed on the site.
subsequent times, others ; but they were all carried away,
sometimes by the force of the waves, at others by the debris
of wrecks striking against them.
Solid wrought-iron shafts of different and increasing iron shafts
diameters were, from tinje to time, sunk in the rock, and the 8U
difficulties of the site were such that, during the construc-
tion of the last one, which occupied five years, but 302 J hours
of work could be obtained on the rock, and the cost was
more than £11,000, ($55,000.)
The rock is submerged at high water, and is but little size of rock, and
larger than the base of the tower, which is 41 feet 8 inches base of the tower,
in diameter, 116 feet high, and solid from base to a height
of 39 feet or to the door of the light-house. The thick-
ness of the walls at the doorway is 7 feet 9£ inches, and mlls-
at the top, which is 17 feet in diameter, it is 2 feet. The
shaft is a concave elliptic frustum, the generating curve of
which has a major axis of 236 feet and a minor axis of 40
feet.
The stones are laid in offsets to the level of 40 feet above . Manner of lay-
ing the stones.
the rock, with a view of breaking the sea, and above that
height the surface is smoothly cut.
Each face-stone is dovetailed vertically and horizontally Dovetailing
into the adjoining stones, and every stone is bolted to the
course below it by two 2-inch bolts, of yellow metal for the
exterior, and galvanized steel for the interior stones.
The dovetailing; was adopted, not only for increase of Reasons for
dovetailing.
strength, but to prevent displacement by the sea during
construction, before the superincumbent weight of the ad-
ditional courses could be obtained, and to protect the
cement mortar of the joints from being washed out before
it could be set.
Mr. Douglass stated that the additional cost of the dove- Additional cost
of dovetailing.
tailing was not more than 1 per cent., and that during the
construction there were lost but thirty-four stones, they be-
longing to an incomplete course which it was impossible to
finish at the end of the working-season before the winter of
1865.
On Plate XXI will be found horizontal sections through
the masonry of The Wolf and five other rock light-houses
142
EUROPEAN LIGHT-HOUSE SYSTEMS.
of the same general character, viz : Eddystone, Skerry vore,
Inch Cape or Bell Rock, Minot's Ledge, and Spectacle Eeef.
These sections are taken uniformly at 10 feet above high
water, and are interesting as exhibiting the different
methods of arranging the dovetail joints of the stones to
prevent displacement by the sea.
Number of Considering the exposure of the rock, which may be esti-
mated from the fact tha,t but twenty-two landings and
thirty-eight hours' work could be had upon it during the
first year of the construction ; that the depot where all the
stones were cut was at Penzance, seventeen miles from the
».rock; that the light-house contains 44,506 cubic feet of
granite, and weighs 3,296 tons, it is not surprising that it
cost £62,726, or more than $300,000, a cost which compares
favorably with that of other structures of similar character.
I find in Mr. Douglass's printed narrative of the work
the following interesting table :
Cubic feet of
granite.
Weight.
Cost.
Comparati
table of costs of
seven rock light-
houses.
Total cost.
Cubic feet.
Cost per cu-
bic foot.
Eddystone
& s. d.
40 000 0 0
13 343
£ s. d.
2 19 11
BeUItcck .. .
• 55 619 12 1
28 530
1 19 0
Skerry vore
72 200 11 6
58 580
1 4 7f
Bishop
34 559 18 9
35 209
19 7i
Smalls
50 124 11 8
46 386
1 1 7i
Hanois
25 296 0 0
24 542
1 0 7i
Wolf
62* 726 0 0
59 070
113
Store-room.
Hoisting - d e r-
rick.
The first room above the solid part of the tower, (to which
access is obtained by a strong ladder reaching from the
rock and bolted to the tower,) as well as the next above, is
used for stores.
The latter room has an opening through the wall of the
tower, through which a derrick can be run out; by means
of this and a winch inside are hoisted the oil and other sup-
plies of the light-house.
The next room above is the oil-room; then come suc-
cessively the kitchen, the bed-room, with five recesses in
the walls for beds, and lastly the service or watch-room.
The dioptric apparatus is of the first order, manufactured
by Chance Brothers & Co., of Birmingham, and shows alter-
nate red and white flashes at intervals of thirty seconds.
investigation Previously to the construction of the lens an investiga-
te determine IMB tion was entered into by Professor Tyndall, the scientific
Ltefvention3 o^adviser of the Trinity House, to determine the loss of light
caused by the rays passing through the red glass, and it
was found that for an equal range of the red and white
light from the same lamp it was necessary to make the arcs
Oil-room.
Apparatus.
P-ATE
St Agnes Revolving WMteJMfht
!>«. Interval 'ofjltusj, Onr.M~inute
EUROPEAN LIGHT-HOUSE SYSTEMS. 143
of the red and the white sectors in the ratio of 21 to 0 Ratios of areas
of red and white
nearly ; and this rule was followed at The Wolf, so that its sectors.
beams of red and white light have the same value.
The lantern is of the cylindrical helically framed kind, i-antem.
and upon the lantern-gallery is placed a fog-bell, struck by F°s-belL
means of machinery placed within the pedestal of the lens.
There is but little wood used in the construction of the Gun-metal used
interior of the light-house, and all of the doors, the window- frames! &c.d °
frames, and storm-shutters are of gun-metal. I was told
that bronze was habitually used for window-frames and
sash-bars at rock-stations, and oak for those of shore-stations.
The windows of the watch-room are arranged, as shown watch-room
windows.
in Plate VIII, for admitting air to support combustion in the
lamp, by means of a valve in the upper part, the current
passing over the heads of the keepers and through the
grating which forms the lantern-floor.
As at other stations, I observed that the floor of the ex- Floor Of ian-
terior lantern -gallery, unlike ours, is made of stone with
raised joints, i. e., the surfaces for about one-half an inch on
each side of the radial joints do not partake of the inclina-
tion of the general surface, but are quite level.
There are four keepers belonging to the station, and three Number of
of them are constantly in the tower, while the fourth is on
shore with his family.
The stated term of service on duty on the rock is one Term of service
month, but it sometimes happens that eight weeks or more before relieve(1
elapse before a sea can be found sufficiently quiet to make
a landing practicable.
As before stated, the rock upon which the light-house
stands is submerged at high water, and the winch, mast,
and boom of the derrick used for landing the keepers,
visitors, and provisions are, when not in use, laid into deep
troughs or recesses in the stone and strongly fastened down
to protect them from the sea.
It was a comparatively calm day when I went to The Method of lami-
Wolf, and I was fortunate in being" able to land upon the^fkupon the
rock ; but it is an undertaking attended with a good deal of
danger, and many trials and much delay were experienced
before we were successful.
The landing-boat, which is well adapted for~the purpose, Landing-bout.
is built diagonally of two thicknesses of elm-plank, without
timbers or floor, and is provided in the bow with a landing-
deck and stake.
This deck and the forward part of the gunwale are cov-
ered with rough rope-matting to prevent slipping in jump-
ing into or from the boat, which is warped in by means of a
144 EUROPEAN LIGHT-HOUSE SYSTEMS.
line made fast to a buoy astern and two lines from the bows,
the latter of which are managed by the men on the rock.
The person who is to land is provided with a cork life-
belt, and stands on the landing-deck forward, holding the
stout mast or stake with both hands, and when the proper
instant arrives, of which he is warned by the coxswain, who
watches the waves and manages the line astern, he seizes
the rope which is lowered from the end of the derrick-boom,
places one foot in the loop at the end, and is quickly hauled
up by the men at the winch on the rock.
Danger attend. Lauding by the mode I have described is comparatively
safe, but is often impracticable, and sometimes when the
keepers are relieved they are pulled through the surf into
the boat when it cannot get near enough to the rock to per-
mit of their being dropped into it.
Thie light-house is one of the most striking examples of
rock light-house engineering for which Smeaton's Eddystone
has furnished the model.
More of this There are now several of this type in the various countries
houses °fn Great of the globe, but Great Britain possesses more than any
Britain than else- ..
where. Oilier.
Notable in- In the United States we have notably two ; one built by
united states. 1 General Alexander, of the United States Engineers, on
Miuot's Ledge, off the coast of Massachusetts, where the
rock is exposed to the full force of the Atlantic, and is only
uncovered at extreme low water ; the other proposed by
General Eaynolds and built by General Poe, both of the
United States Engineers, and the latter now a member of
the Light-House Board, on Spectacle Eeef, in Lake Huron,
the site of which is 10 feet below the surface.
spectacle Eeef, The latter, however, was quite a different problem from
difficulties met in ... ,
building. any of the others in that the structure was to withstand
the immense fields of moving ice by which it is assailed in
the spring.
I regret that I could not visit the other rock light-houses
of England, or the Skerry vore and Bell Rock, the latter of
which have given so enviable a reputation to the Stevensous,
the distinguished family of Scottish light-house engineers.
THE RUNDLESTONE BELL-BUOY.
The bell-buoy which marks the Kundlestone, off the point
of Laud'sEnd,is 10 feet in diameter at the water-line, moored
Moorings. with 45 fathoms of 1 J-inch chain and a 30-cwt. sinker, which
is backed with 30 fathoms of IJ-iuch chain, and a second
sinker of the same weight.
d
m
o
7)
EUROPEAN LIGHT-HOUSE SYSTEMS. 145
The bell weighs 3 cwt. This is a water-ballast buoy, and
is shown in Fig. 15, in which a is the outer water-tight
compartment; &, the inner water-tight compartment; d, d,
the India-rubber springs.
Fig. 15.
Rundlestone Bell-buoy.
THE SEVEN STONES LIGHT-SHIP.
This vessel, which marks the dangerous shoal of rocks in- Position.
dicated by its name, lies about twenty miles to the westward
of Land's End, or about midway between it and Saint Agnes
(Scilly Islands) light, in what is probably one of the most
exposed positions in the world for a light-ship.
It is one of the latest constructions, and has been on the Age.
station about two years.
It has two inasts, besides the mast for a jigger or miz- Masts ami ap
zen, which is stepped on the taffrail. The former carry two
fixed catoptric lights, 28 and 20 feet above the sea.
A fog-trumpet, of Professor Holmes's patent, shown in Fog-trumpet.
Plate XXII, is operated by a hot-air engine, the cylinder of
which is 24 inches in diameter.
The engine is placed between-decks, amidships, and the Engine and
horn between the masts on deck.
I should think the utility of the signal much impaired by Length of time
the length of time required to generate sufficient pressure
to operate it, which I was informed is an hour and three- '
quarters.
This is a serious objection in any fog-signal, since the fires
are ordinarily not started till the fog comes on, and in the
S. Ex. 54 - 10
146 EUROPEAN LIGHT-HOUSE SYSTEMS.
long interval before the warning is given serions accidents
are liable to occur.
"Heaters" used For our signals operated by steam, we frequently provide
s " heaters," by which, with a very small expenditure of fuel^
the water in the boiler is kept hot, so that when the signal
is required, a quick fire will raise the pressure to the required
point in a few minutes.
can The fog-signal on'the Seven Stones can be operated by
lSnd.perated by hand, by means of a pair of air-pumps on deck, in case of
accident to the hot-air engine, or when waiting for the re-
quired pressure, but it is extremely hard work for the sea-
men, and I fancy the signal may not be satisfactorily sounded
at such times.
signal- gun There is also a signal-gun on deck which is fired when a
fired when ves- , . , . . • , n
are seen vessel is seen standing into danger.
The measurement of the Seven Stones is 188 tons. It
crew-
moored in 41 fathoms of water by 200 fathoms of 1J-
inch chain to a mushroom anchor weighing 40 cwt. Three
hundred and fifteen fathoms of chain can be run out when
necessary.
Crew< This light-ship carries a crew of fifteen men besides the
master and mate ; one of the latter and five of the seamen
uniforms ofare constantly on shore with their families. They are all
uniformed, and the name of the vessel is marked upon their
hats and shirts. This rule applies to the crews of all the
light-ships of England, and to those of the yachts or tenders
belonging to the Trinity House.
THE LONGSHIPS.
Location. The Longships is the name of some rocks about a mile
and a quarter to the westward of Land's End, on the largest
of which is the new first-order light-house of that name,
which, at the time of my visit, was on the point of coaiple-
tion.
Rough seas As at The Wolf, the sea is generally rough at The Long-
prevalent. ships, and when we approached it on our return from the
Seven Stones light-ship to Penzance, we found it impossible
to land. The following day, however, we made another
attempt, and were successful.
Form of rock. The rock on which the tower is built is conical in form,
and rises about 60 feet above the sea ; and the tower, which
is precisely like that at The Wolf, is placed on a ledge
in front, about 20 feet above the sea. The rock in the rear
was being blasted down to the level of the top of the .solid
part of the tower, at which is the door or entrance.
HOLMES'S FOG-HORN APPARATUS. PLATE
XXII.
ft. (bch between>Hanc&Iltm]ps.
a. Cratik.
". Gem tifctiria Root.
fc.
EUROPEAN LIGHT-HOUSE SYSTEMS. 147
Mr. Michael Beazeiey, the resident engineer in charge of Mr. Beazeiey,
the construction of The Longships, was also in charge of The eu
Wolf light-house, and I am much indebted to him for kind
attentions on the occasion of my visits to these stations, and
for information in regard to the works.
The courses of stone at Longships were dovetailed, as atbu^(g*hoa of
The Wolf, but as the rock which was blasted away for the
site for the tower, was an extremely hards late, a "core" of
it was left in the interior to a considerable height.
These courses, to the height of the solid part of the tower, Thickness ot
7 the stone-courses.
were 2 feet in thickness, and above that height, 1 foot 6
inches.
Quick-setting cement was used for setting the . lower Cement used-
courses, and strong muriatic acid for removing the sea- weed
from the rock, though Mr. Beazeiey stated that lime is better
for this purpose, if at least two hours can be had before it is
covered by the tide.
The focal plane of Longships light-house is 110 feet above o^al Pbne of
the sea.
The handsome new lantern was in place, but the lens was Deflectors in
not set, and nineteen reflectors were ranged temporarily
around the inside of the lantern to cover the proper arc of
the horizon.
As at nearly every light-house which I visited on the coast Red cuts.
of England, there are outlying dangers marked by " red cuts."
(See Plate XX.)
At Longships these dangers are on one hand "The Bri- gangers mark-
sons" rocks, and on the other " The Bundlestone," each about
six miles from the light-house, and being well out from the
land, they were for many years the terror of navigators.
By the system of marking out these dangers by means of
red light, they can, however, be avoided with absolute cer-
tainty in all weathers, except when the light is obscured by
fog.
As an evidence of the force of the waves off Land's End,
it may be mentioned that before the commencement of the °fl
new tower at The Loogships, a granite light-house, the focal
plane of which was 79 feet above high water, occupied the
site ; but owing to the terrific seas to which it was exposed,
the lantern was so often under water in stormy weather that
the character of the light could not with certainty be deter-
mined by mariners, and the erection of a higher tower
became necessary.
148 EUROPEAN LIGHT-HOUSE SYSTEMS.
GODREVY.
This light-house is on a rock off the west coast of Corn-
wall, and about twenty miles to the northward of The Long-
ships.
Between this rock and the mainland is a smaller rock, on
Manner of land- which the landing is effected. A wire rope is stretched
from one rock to the other, and a basket suspended from it,
is run over the rough water intervening, and by this means
the keepers and stores are carried to the station.
When the Vestal approached the rock the keepers sig-
naled that a landing was impracticable, and we steamed
away without visiting this interesting station, much to my
regret.
" The stonee." A mile and a quarter outside of Godrevy are some sub-
merged rocks called " The Stones," a source of great dan-
ger to the mariner. They are unmarked except by a buoy,
but are covered at night by a beam of red light from God-
revy light-house. (See Plate XX.)
intention of As an evidence of the intention of the Trinity House to
p/acet^c light on serve the best interests of commerce, Captain Webb men-
tioned that before the light-house was built, the Corporation
proposed to place the light upon one of " The Stones," but
was overruled by the Board of Trade. The expense of the
proposed structure was but a few thousand pounds more
than the cost of the actual light-house, and the latter has
the same expense of maintenance and the same dangers in
landing supplies of oil, &c., which the former would have
had, while the very important advantage of marking "The
Stones" is not gained.
"THE STONES" BUOY, OFF GODREVY.
This buoy is an " egg-bottom," water-ballasting, 13 feet
Moorings. loug, moored in 60 feet of water with 45 fathoms of IJ-inch
chain and a 30-cwt. sinker, which is "backed" by 30 fath-
oms of IJ-inch chain and another sinker of 30 cwt.
Although this is probably one of the most exposed places
around Great Britain, the moorings of this buoy are so
excellent that it has not been adrift in three years.
After leaving Godrevy we landed at Saint Ives, on the
doneturnt°*Lon"west coast of Cornwall, and went up to London by rail,
arriving there on the 1st of July. I cannot conclude the
notes on my journey on the southwest coast of England
without expressing my sincere thanks to Captain Webb for
his kindness and his constant efforts to make the cruise
instructive and interesting for me, and for the many polite
EUROPEAN LIGHT-HOUSE SYSTEMS. 149
attentions which I received from him, from, the time I first
arrived in London till my departure for America.
On the 2d of July I attended the annual dinner at the
Trinity House, which takes place on Trinity Monday, at House.
which were present His Royal Highness the Princeof Wales,
the Czarowitch (eldest son of the Czar) of Russia, the
Dukes of Argyll and Richmond, and others of the nobility,
the Queen's Ministers, and other distinguished personages.
His Royal Highness the Duke of Edinburgh, Master of
the Trinity House, presided, and during the evening I had
the distinguished honor of being presented by him to His
Royal Highness the Prince of Wales. They both kindly
referred, as the former had done before (as I have men-
tioned) at the dinner of the Lord Mayor, to the satisfaction
which Sir Frederick Arrow and Captain Webb, of the Elder
Brethren, had expressed in regard to their visit to the
United States and inspection of some of our light-houses.
Before proceeding to Ireland and Scotland I visited the
Continent, but I will here continue my account of the
British lights in the order in which I visited them after my
return.
HOLYHEAD.
Leaving London by train on the 14th of August, I arrived
at Holyhead, on the Island of Anglesea, the following day,
where I met, by appointment, Mr. Douglass, the engineer of
Trinity House, and had the pleasure of inspecting with him
the Trinity House light-stations on the island.
The great breakwater for the protection of the harbor of Breakwater to
refuge at Holyhead, together with the light-house at its Eor of refuge. ai
outer end, had just been completed; the latter, although
quite finished, was not to be lighted until a few days later,
when there was to be a grand demonstration to celebrate
the completion of the harbor works, at which the Prince of
Wales and several members of the government were to be
present. The light-house, which was built from designs Light-house.
approved by the Trinity House, by Mr. Hawkshaw, the dis-
tinguished engineer in charge of the breakwater, at the ex-
pense of the fund appropriated for the latter, is a handsome
tower of granite surmounted by a flashing lens of the third Lens
order, made by Chance Brothers. Outside the parapet of
the tower is placed a fog-bell, rung by machinery, which, Fog-beii.
together with the usual revolving machinery, is contained
within the pedestal of the lens. The latter revolves upon
conical wheels, the outer bearing-surfaces of which yre flat Fiat wheels
used for revolv-
and not beveled as in the French system and our own. ing machinery.
150
EUROPEAN LIGHT-HOUSE SYSTEMS.
amp
Mr. Douglass stated that wheels of the latter kind wear
into the rail rough channels, which increase the friction and
interfere with the regularity of motion, which is essential in
weigbtsof the revolving machinery of light-houses. The lamp, a "mod-
erator" of Chance's manufacture, is like our own, except
that the weights are hung underneath the cylinder or reser-
voir, and are connected with the plunger by means of exte-
rior rods.
The plain pulleys and rods formerly used for revolving and
fog-bell machinery have been replaced by chain- wheels and
chains which are much more durable and reliable.
Fig. 16.
Lamp of single
and double pow-
er.
Lamp of Single and Double Power.
The burner, shown in Fig. 16, contains all the recent im-
provements, one of which gives to the lamp its name of the
EUROPEAN LIGHT-HOUSE SYSTEMS. 151
" lamp of single and double power." In the figure a a is the Explanation of
focal plane; 1) &, the level of the mineral-oil; c c, the overflow- fij
holes, eight in number, and three-sixteenths of an inch in
diameter; d, the interior, and e the exterior deflector. The
adjustable chimney, the perforated button, and the conical
tips to the burners are also shown.
Between the exterior deflector or jacket, and the chimney,
there is an air-space, open at the bottom, through which a
draught of cold air passes and keeps the base of the chimney
so. cool that it can be removed by the naked hand, as I
found by experiment, without the use of the tongs usually
required. These burners have three wicks, the exterior
2|, the middle If, and the interior J of an inch in diameter.
By a simple movement the inner wick can be lowered
into the burner and extinguished, or raised and lighted.
This and the change of the perforated buttons require but Power of ad-
an instant, and the result is, that the flame and the amount imi^onsumption
of oil consumed can be exactly adjusted to the quantity of of
light required.*
In fair weather only the outer and middle wicks are
burned, but when fog or thick weather comes on, the per-
forated button is changed, and the inner wick is raised and
lighted.
This is of great importance in the economy of light-house Economyoftho
illumination, and the English have been, as far as I am burner-
aware, the first to attempt to vary the power of oil-lights;
a result which has been effected, as I have before stated, in
both the gas and the electric lights.
Photometric experiments have shown that the flame of p0wer of the
the outer two wicks is equal to 146 candles, and the lightiuginne™ckflamc-
of the small interior wick raises the power to 208 candles,
showing that, though the inner wick has but 19 per cent, of
the total burning- surface, it yields 30 percent, of the entire
amount of light, an amount very much in excess of its
power when burning alone ; but it must be considered that
the circumstances of combustion are much more favorable
when the wick burns inside the larger flames.
The lantern at Holyhead is of the latest kind. The sash- Lantern with
bars run diagonally from top to bottom, and the panes
glass are of a lozenge shape, cast in cylindrical form, cor- drical slas8-
responding to the diameter of the lantern. With regard to
the diagonal sash-bars, Mr. Douglass stated that Faraday,
the predecessor of Professor Tyndall in the oflice of scientific
adviser of Trinity House, found that the vertical bars, Obstruction of
which were at one time used, obstructed at least 48 per ight by vertical
cent, of the light in certain directions, whereas with diag-
152 EUROPEAN LIGHT HOUSE SYSTEMS.
oiial bars the shadow was lost at a distance of less than a
hundred feet. In discussing this matter Faraday consid-
ered that the rays of light issuing from the lens in any di-
rection, form at the exterior surface, a beam, a vertical sec-
tion of which is a column of light of the height of the lens ;
that with diagonal bars the beam from this column of light
intersects them in points, the shadow of which, the beam
being broader than the sash-bars, is terminated not far out-
side the la'ntern, while with vertical bars the best part of
the beam is partially obstructed, and a vertical shadow is
thrown upon the sea.
Extract from The following extract from a report by Professor Tyndall
° ' of experiments with gas and oil burners at Howth Baily
light-house, Dublin Bay, confirms this view:
" I did not, however, think it safe to limit myself to this
particular point of observation, and to meet my wishes, Cap-
tain Roberts was good enough to engage a steamer, which
enabled me to proceed down the river and to pass across it
from side to side between the North Wall and the South
Wall, thus varying the points of observation.
ult soon became manifest that the oil-flame at Howth Baily
varied in intensity with our position, and that the direction
of minimum intensity corresponded almost exactly with that
in which our observations had been made on the previous
evening from the North Wall.
" No safe conclusion, therefore, could be drawn from the
observations made on the evening of the 7th, for it was
manifest that some cause existed which prevented the oil-
lamp from displaying its full power in the direction of the
North Wall, thus giving the gas a relative superiority, which
in reality it did not possess.
" It is to be borne in mind that the oil-lamp in these ex-
periments was placed in the first- order dioptric apparatus
of the light-house, the apparatus being, as usual, surrounded
by its glazed lantern. The gas-flame, on the contrary, was
placed in a temporary hut at some distance below the lan-
tern. A refracting- pan el, similar in all respects to those of
the dioptric apparatus, was placed at the proper distance in
front of the gas-flame, and to make the conditions alike, the
upper and lower reflecting-prisms of the apparatus were
shut off. It was, therefore, the lights transmitted through
the two lenticular belts that were compared together.
"In company with Captain Roberts, I again visited
Howth Baily on Wednesday, the 9th.
" We were preceded by Captain Hawes and Mr. Wig-
EUROPEAN LIGHT-HOUSE SYSTEMS. 153
ham, who were instructed to examine with all care whether
any obstruction was offered by the lantern to the passage of
the light toward our station on the Xorth Wall.
ult was soon found that one of the vertical sashes of the
lantern was directly interposed between the light and our point
of observation, and that to this obstruction the enormous appar-
ent superiority of the gas flame over the oil, manifested on the
evening of the 7th, was to be ascribed.
" Since my return to London, Captain Roberts, at my re-
quest, placed the gas-flame in the dioptric apparatus and
the oil-flame in the hut below. From the North Wall the
oil-flame was the" brightest, thus affording additional evi-
dence, if any were needed, as to the influence of the obstruc-
tion offered by the sash of the lantern."
M. Quinette de Eochemont, engineer des Fonts et Chaussees, Te^™f Mfrotg
who is charged with the supervision of the French lights Rochemont.
north of the Lower Seine, in his " Note sur les Phares Elec-
triques de la Heve? referring to experimental comparisons
between the electric lights at La Heve and the oil-lights at
Honfleur, Fatouville, and Ver, remarks as follows :
" The observations at Fatouville show an anomaly, but
this is easily explained, as it was in consequence of one of
the uprights of the lantern of the northern (oil) light-house
being placed in the direction of Honfleur. and thus obscur-
ing a considerable part of the light from the apparatus."
This matter is still further illustrated by Fig. 17, in English and
American Ian
which a section of the beam is shown, partially eclipsed in terns.
one case by a vertical sash-bar of the lantern a, constructed
on the American and French plan, and in the other crossed
by the diagonal sea-bars of an English lantern, &, the width
of the beams being drawn the same in both cases.
In 1873, the engineer of our seventh light-house dis- complaints
made of the light
tnct reported to me that grave complaints were made of at Key west due
. to shadows cast
the light at Key TV est, it having been reported by mariners by broad sash-
to have been extinguished on several occasions.
On investigation it was found that such large shadows were
cast by the great sash-bars of the old-fashioned lantern
of the light-house that vessels were sometimes in shadow
for a long time, and to this cause, and not to the want of
vigilance on the part of the keeper, were the above reports
due. This old lantern has since been replaced by one of the
new model, in which the width of the sash-bars is very much
less than in the old.
I have been thus particular in referring to the subject of ob- Error of the
struction by vertical sash-bars in light-house lanterns, since oV^sYn? vSS
in our service vertical-barred lanterns have always been barrcd lanterus-
154
EUROPEAN LIGHT-HOUSE SYSTEMS.
used, and I believe it to be a very serious error into which we
have been led by an improper consideration of the matter.
cylindrical ian- Mr. Douglass stated that he had found by experiment
that cylindrical lantern-glass is 68 per cent, stronger than
plate-glass, an important consideration to us, particularly
with regard to our southern coast, where our lantern -glass,
•oi?£Seib ^ tea8 Chough one-half an inch in thickness, is frequently broken
by sea-fowl, which, blinded by the light, fly against the lan-
tern, damaging not only that, but the lenticular apparatus,
to such a degree that we have been obliged to cover the
entire face of lanterns with netting, necessarily of such
strength and size of wire as to impair the value of the light.
Fig. 17.
fowl.
Low parapet
used on English
towers.
Ventilation.
American aud English Lanterns.
With further reference to the English lantern, I will remark
that the substitution of the low parapet in place of the high
one used by the French and ourselves does not seem to me to
be an improvement. The former necessitates the use of a step-
ladder when cleaning the lenticular apparatus, and the door
for reaching the outer gallery is necessarily low and incon-
venient. The English provision for egress of heated air
and smoke is not as good as our own, and the arrangement
for turning the cowl with the wind I should think liable to
become obstructed by soot and dust. I have the same
opinion with regard to the manner of providing fresh air to
support combustion in the lamp. The English admit this
"EUROPEAN LIGHT-HOUSE SYSTEMS.
155
into the watch-room and thence through the grating of the
lantern-floor. (See Plates VII and VIII.) It is true that the
tops of the ventilating windows in the watch -room are above
the heads of keepers on watch, but in our cold latitudes this
would be quite inadmissible, and in no case do I perceive the
English mode to be in any way superior to ours of admitting
the exterior air directly into the lower part of the lantern.
The excess of 2 feet in the diameter of their lanterns Superior size ot
lantern used by
over our own I think unnecessary, as we have found 12 feet the English not
to be quite sufficient, affording abundance of space between vantage to com.
. ., ~ ... pen sate for the
the lens and the lantern -sides. On our eastern coast, with consequent in-
M i • , ,-, n CL f> -IT creased cost of
our necessarily high towers, the expense of 2 feet addi- towers,
tional to the diameter of lanterns and towers is much greater
than in England, where the towers are ordinarily on elevated
sites, requiring but small elevations of the lights.
NORTH STACK.
This fog-signal station is about four miles south of Holy-
Fig. 18.
Wind-guard.
head Harbor, on the east side of Saint George's Channel. The
156 EUROPEAN LIGHT-HOUSE SYSTEMS.
Fog-signal. signals, which are in charge of two keepers, whose sole duty
is to attend to them, are a pair of 18-pounder guns, placed
in a masonry building and fired through embrasures, in
thick and foggy weather, at intervals of fifteen minutes,
the charges being three pounds of powder.
As most of the steamships and other trade to Liverpool
pass quite near this point, and fogs are common, this is a
steam -whistle most important signal; but I am convinced that the long
guuf?inbu1eto tlie intervals between the discharges make it less valuable than
a powerful steam-signal, either a whistle, siren, or Daboll
trumpet, would be.
It is to be remembered that an increase in the number of
discharges would materially add to the already heavy ex-
pense.
wind-guard I observed on the dwelling of the keeper a wind- guard,
which Mr. Douglass stated was designed by Faraday, and is
in common use in the light-house service as well as through-
out the country. In the most trying positions, such as
North Stack, which is under high land rising immediately
in the rear, it effectually prevents the annoyance, so frequent
in such localities, of the smoke being driven down the chim-
ney during high winds. A sketch of this chimney-top is
shown in Fig. 18.
SOUTH STACK.
This light-house, at the extreme westerly point of Holy-
head, the extremity of the Island of Anglesea, is about five
miles south of the harbor, in a remarkably picturesque lo-
cality.
From the elevated laud in the rear, one descends by a flight
of 450 steps to a handsome suspension-bridge thrown over
the chasm separating the South Stack from the Island of
Anglesea.
characteristics This light is catoptric, revolving, and of the first order,
having eleven reflectors on each face.
rog-beii. At this station the fog-bell, weighing two and one-half
tons, is placed with its mouth uppermost. A counterpoise-
weight is hung underneath the axle, which is turned by
Manner o f machinery placed under cover. The hammer is within the
sounding the fog- belL Tne axle of the cog.wheel w^ich moves the bell and
its counterpoise, passes through a slot in the side of the
machine-house, and has a slight vertical motion. Great
power is not required for ringing this bell, which has been
in use for many years, giving entire satisfaction to mariners.
Plate XXIII.
FOG, OR OCCASIONAL LIGHT AT SOUTH STACK
ST. GEORGE'S CHANNEL.
EUROPEAN LIGHT-HOUSE SYSTEMS. 157
The only fog or " occasional " light for use at light-stations Fog or " occa-
in thick weather of which I have any knowledge, is at South 81(
Stack.
It is well known that while lights in high towers and on High lights ob-
considerable elevations of land, can be discerned in clear 8C
weather at the maximum distance, (in our service, as in
others, about twenty miles,) an object of the first importance,
great elevation of site is a disadvantage in foggy weather,
since the fog-clouds frequently maintain themselves at a con-
siderable height above the sea, and envelope the light when
it is clear below.
At many points in our Pacific States, the coast rises so Io£a8£ghtswhare
abruptly from the sea that no sites can be found at a suffi- eein foggy
ciently low elevation to avoid this difficulty, even when low
towers are erected, and the arrangement I saw at South
Stack provides a remedy for the obscuration of light during
foggy weather.
An inclined plane has been excavated in the rock, and a
tramway laid thereon. The fog-light is contained in a car-
riage, which in clear weather is kept at the summit of this
plane near the main light-house, but during a fog is lowered
by means of a windlass to a position where, safe from the
waves, it is still as near the sea as possible. The forward
part of this movable light-house is glazed, and contains a
catoptric apparatus of three reflectors in the same plane, on a
revolving frame which has a reciprocal motion through the
exact arc to be illuminated, thus giving the characteristics
of the main light.
A weight for driving the machinery in this case being, as du^naDSth°ef
is evident, out of question, the motion is produced by means °I1
of a powerful spring.
This ingenious light has been in operation for many years,
(I believe since 1832,) and has proved to be of great advan-
tage. Captain Moodie, of the Cunard line, with whom. I re-
turned to America, told me that frequent occasions had been
afforded him for testing its value, the light at Holyhead
being of the first importance to the immense traffic through
Saint George-'s Channel, where, at some seasons of the year,
habitual fogs prevail. Plate XXIII will give an idea of this
construction.
Before closing my notes in regard to the English light-
i • -r j i i • it* ment of atten-
house service, I take pleasure in recording my obligations tions received
to Sir Frederick Arrow, the Deputy Master, to the Elder £S? **
Brethren, and to Mr. Douglass, the engineer of the Trinity Hou8e<
House, for the attentions and kindnesses of which I was
constantly the recipient, from the time I arrived in England
158 EUROPEAN LIGHT-HOUSE SYSTEMS.
till my departure for America. There was no facility for
acquiring information in regard to the object of my journey,
no act of hospitality which could suggest itself, which was
not proffered with that hearty generosity for which their
countrymen are distinguished.
Drawings, de- While in London I was furnished with drawings, descrip-
SveT'ffom tions, &c., of many of their light-houses and accessories, and
Trinity House. sjnce my retum I have received others which have been of
much assistance to me in the preparation of this report, and
I am happy to believe that such relations are now estab-
lished as will lead in the future to that interchange of infor-
mation which is desirable in this most interesting and im-
portant service.
Although I should have been glad to avail myself of the
kind invitation of Admiral Schomberg, Harbor-Master at
Holyhead, to whom I am indebted for polite attentions, to
remain to witness the demonstration which was to celebrate
the completion of the great breakwater, the limited time at
my disposal would not permit, and on my return from South
Stack, the last English light-station that I visited, I em-
barked in the Irish mail-steamer for Dublin.
IRISH LIGHTS.
Letter from Soon after my arrival in England I received the follow-
iSTigh?f rsof ing letter from the Commissioners of Irish lights :
" IRISH LIGHTS OFFICE,
" Westmoreland Street, Dublin, May 24, 1873.
tl SIR : The Commissioners of Irish lights having been in-
formed by the inspector of lights to this department that
you propose visiting Ireland shortly, and that you were de-
sirous of availing yourself of such opportunity to inspect
one or more of the gas light-house establishments under the
management of this Board, I have the pleasure to acquaint
you that the Commissioners will be most happy to afford you
every facility to carry out your wishes.
" Will you be so kind as to let me know a day or two pre-
viously, as to the probable period of your arrival in Ireland ?
" I have the honor to be, sir, your obedient servant,
"W. LEES,
" Secretary."
" Major GEORGE H. ELLIOT,
" Corps of Engineers, United States Army."
I reached Dublin on the 16th of August, and on my ar-
rival proceeded to the office of the Commissioners, where I
was politely received by Mr. Lees, who seated that the Com-
ISITY
EUROPEAN LIGHT-HOUSE SYSTEMS. 159
missioners were at that moment, according to previous ar-
rangement, embarking for Holyhead to take part in the
celebration at that place, and wished him to convey to me
their regrets that they were unable to meet me, and to in- T inspection <>i
J Irish gas-lights,
form me that Captain Hawes, the inspector of Irish lights, with Captain
(whom I had the pleasure of meeting at South Foreland on Wigiuw*.
the Straits of Dover at the commencement of the fog-signal
experiments of which I have given an account,) and Mr.
Wigham, . the inventor of the Irish gas-light for light-
houses, would take me to such of their establishments as I
should desire to visit.
We soon set out by rail for Howth Baily, the northern
head of Dublin Bay, where is a first-order fixed gas-light ;
after describing this station and that at Wicklow Head,
where is a first-order intermittent gas-light, I shall give a
general description of the Irish gas-lights for light-houses,
derived from information received from Captain Hawes and
Mr. Wigham as well as from, observations made on my
visits to the above-named stations, and to the English gas-
light at Haisborough.
HOWTH BAILY.
This station, (see Plate XXIV,) on a bold promontory at First light
J where Wigham's
the outer northern limit of Dublin Bay, is of interest as g^- light was
being the first station at which the Irish gas-light patented
by Mr. Wigham was established ; this was in 1865.
An inspection of Plate XXY will show the compactness Little space
_ . , ... _, required for gas-
of the gas-works, comprising retort-house, gas-holder, &c. works.
Few light-house sites are too limited to contain buildings
necessary for the apparatus. The gas holder at this station
contains 800 cubic feet, but is considered too small, a disad-
vantage not found in later establishments of this kind.
Uniformity of pressure of gas at the burners is obtained uegubtor to
by means of a regulator, also of Mr. Wigham's design; and Ft^of p6re°sni-e™t
I will here mention that this burner is but one of many ga
curious and ingenious inventions led to by, and necessary
for, the proper development of the system.
As at Haisborough, I saw here from actual trial that the Substitution of
r. -, • -i . °*1 f°r gas-light
ordinary first-order oil-lamp, which is always ready, can be when necessary.
substituted for the gas in less than two minutes, and the
7 Changeof
Irish regulations require the keepers, for the purpose of jWs required
keeping in practice, to change the gas for the oil light once
a month.
The changes of the burners and the mica oxydizers to Manner o*
meet the varying -atmospheric conditions, require but
instant, the change of the burners being accomplished
160 EUROPEAN LIGHT-HOUSE SYSTEMS.
simply by setting into, or lifting out of, the mercury-cups,
the short pieces of supply-pipe to which are attached the
semi-cylindrical rings of jets, and by opening or changing
the cocks.
bura^lS Powf The largest burner, having a diameter of 10J inches, con-
r of flame. tains 108 jets, and the immense body of flame carried to the
mouth of the mica oxydizer (see frontispiece) is most daz-
zling.
Heat. The heat, as may be conceived, was very great, but the
keeper said it gave him no inconvenience, nor did it injure
the lenticular apparatus, thus corroborating the information
given me at Haisborough. The lens is in no respect dif-
ferent from the ordinary fixed lens of the first order.
Keepers. Employed at this station are two keepers, one apprentice
under instruction, and a gas-maker, the latter receiving
2s. Qd. (62J cents) a day. Captain Hawes considered the
employment of the gas-maker quite unnecessary, the labor
at any gas light-house being easily performed by two
keepers.
Eog-beii. There is at Howth Baily a fog-bell, operated at present
by an Ericsson engine, but for some years a gas-engine was
used, which was, I believe, discontinued in consequence of
the insufficient size of the gas-holder.
Superiority of Mr. Wigham, who constructed the works at both Howth
light at Howth
Baily and Haisborough, stated that at the former place the
light was much the purer and whiter, owing to the burner
being supplied under much greater pressure. Captain
Hawes is of the opinion that 28 jets are here quite enough
in clear weather, while 48 are habitually used at Hais-
borough.
WICKLOW HEAD.
This station, on the western side of Saint George's Chan-
nel, south of Dublin, we reached partly by rail and partly by
"jaunting-car," a two-wheeled vehicle, which is the common
conveyance of the country.
osn a ^ne gas-house, containing the furnaces and retorts, the
works. gas-holder, and other buildings, are ingeniously disposed on
the face of a high cliff, and occupy but little space, as
shown by Plate XXVI.
characteristics This is a first-order intermittent light, the lens-apparatus
maniierlgof ' pro- being that of an ordinary fixed light. The gas is let on and
shut off by an automatic arrangement which allows ten
seconds of light and three seconds of darkness. This
arrangement does not cut the gas entirely off, and each jet
during the three seconds' eclipse shows a tiny blue flame,
which, while it produces no illumination of the lenticular
EUROPEAN LIGHT-HOUSE SYSTEMS. 161
apparatus and can scarcely be detected in the daylight,
is still sufficient to light the main body of gas when the
supply is turned on.
To guard against all danger of total extinguishment of "By-pass," to
the light by gusts of wind through the ventilators or door jSg'ui
of the lantern, each jet is surrounded by a small pipe called 1J
the " by-pass," the top of which, being at a level with the
tip of the jet, is pierced by several minute holes through
which gas is supplied from a pipe quite independent of the
automatic cut-off; thus protected, these little jets of flame
burn from the moment of lighting at sunset to that of
extinguishing at sunrise, and it is impossible even if the
" cut-off" or a gust of air should completely extinguish the
main flame that the burner should not be lighted at regular
intervals of thirteen seconds.
The two keepers at Wicklow Head agreed with those at ^
Howth Baily in saying that the gas gives very much less us^t.
trouble than the oil light.
DESCEIPTION OF WIGHAM'S GAS-APPAEATUS
FOE LIGHT-HOUSES.
FIXED GAS-LIGHTS.
The light is produced by a burner shown in the Plates
XXVII and XXVIII. It is capable of producing five differ-
ent degrees of power according to the state of the atmos- 5^. powers of
phere, the first power being produced from 28 jets of gas. Fir8t P°wer;
Each jet consists of a hollow tube with an ordinary fish-tail
burner of lava at the top. At the bottom of each tube is
placed a small lava cone bored with fine holes, (one on each Regulator,
side.) the effect of which is to act as a regulator and to allow
tbe gas to enter the air at such a rate of speed as is found
most conducive to its combustion in connection with the
overhanging oxydator, which is formed of talc, and which is
fitted with terminal pieces to suit the respective sizes or the
various powers of the burner. The second power is pro- Second power.
duced from 48 jets as above, except that some of the orifices
in the lower cones are slightly larger than in the smaller
burner. The third power is from 68 jets, with slight altera- Third power,
tions in the orifices of the lower cones and also of the upper
jets. The fourth is from 88 jets, and the fifth is from 108 Fourth and
jets as above. The flame of the latter is shown in the frontis- fi
piece.
Tbe rings which contain the jets for the several powers,
except the first, are removable and replaceable at pleasure.
Mercurial cups, each fitted witii a ground-in valve, are the
S. Ex. 54 11
162 EUROPEAN LIGHT-HOUSE SYSTEMS.
means employed to facilitate this application. The whole
of the gas supplied to the burner passes through a chamber
of cast brass, at the bottomof which there is fixed a mer-
curial lute which enables the whole gas-burner to be
removed in a moment, and the ordinary oil-lamp used in
and^substitution dioptric apparatus to be substituted for it. The talc chim-
of oii-iamp. neys are also removable, and arrangements are made by
which the ordinary oil-lamp condenser can be fixed for
the use of the oil-lamp. This arrangement for rapidly
substituting the oil-lamp in place of the> gas-burner was
instituted when gas was first lighted at Howth Baily light-
house, in the year 1865, as a precaution against any acci-
dent occurring to the gas-light, but during the time that has
since elapsed (about eight and a half years) no occasion has
ever arisen for putting this precautionary plan into operation.
Lenses used. By the use of gas in a fixed-light apparatus of any size
there is no occasion to alter the existing lenses, but in some
lanterns it may be necessary to provide for additional ven-
tilation. It will be seen by the table to be found further on
that the photometric values of the flames of the respective
powers of the gas-light are largely superior to any photo-
metric results obtained from the oil-lamp, either for paraf-
Cost of gas- nne or colza oil. The cost of gas-light in Great Britain is
Ught< said to be less than that of oil, comparing only the ordinary
power of the gas-light. Of course, when the fog-powers of
the gas-light are turned on, the cost per hour is greater, but
taking the average of a year's consumption (including con-
sumption for fogs) at several light -houses in Ireland which
are lighted by gas, it appears from a return made by the en-
gineer and accountant of the Board of Irish Lights that there
is a saving of about £65 ($325) per annum at each light-
house by the use of gas instead of oil.
INTERMITTENT GAS-LIGHT.
Burner. The burner used in this case is precisely the same as that
Flashes. in the fixed lights. The intermission in the light is caused
by the opening and shutting of a gas-valve, which cuts off
the supply of gas to the burner for any required period,
and the re-exhibition of the light takes place as soon as the
valve is opened, a small by-pass being provided for keep-
ing a supply of gas in the burner, so small as to render its
flame invisible, but sufficient for the re-exhibition of the
light immediately on the opening of the valve. The open-
ing and shutting of this valve is accomplished by means of
a small piece of clock-work fixed in the room under the
lantern, and which requires to be wound up every four, six,
or eight hours, according to the height of the tower.
Plate XXVI.
OAS LIGHT-HOUSE AT WICKLOW HEAD. IRELAND.
EUROPEAN LIGHT-HOUSE SYSTEMS. 163
Professor Tyndall very clearly illustrates the application ^statemeut^ of
of the intermittent light to revolving lenses in a report to dafi.68
the Board of Trade dated the 7th of February, 1871.
After stating that a gas-burner of 28 jets is almost iden-
tical in size and sensibly equal in illuminating power to the
Trinity four-wick burner, that it is quite as applicable as
the latter to a revolving light, and that a saving can be se-
cured by a periodic extinction of the gas-flame, he says :
"The central octagon figure (see Fig. 19) from which the
rays issue is intended to represent the eight-paneled re-
volving apparatus. The points of the stars are to be re-
garded as the centers of the beams issuing from the respect-
ive panels. The blackness of the disk underneath the star
is intended to denote the darkness of night, while the circle
round the disk represents the horizon.
Fig. 19.
K
O
Diagram illustrating revolving intermittent gas-light.
"Every part of the horizon receives a flash every second
minute, the gas being lighted one minute, during which the
lens is moved one eighth round, and each part receives a
flash, then the gas is extinguished one minute, and so on in
succession. Thus half of the consumption of gas is saved.
" Let the star be turned so that the beam A shall point to ^Description of
and illuminate the station K on the horizon. The ray B
would at the same moment illuminate L ; O would illumi-
nate M ; D, N $ E, O 5 F, P ; G, Q ; while the ray H from the
eighth panel would illuminate E, the eighth station.
" Let the star be turned, or in other words let the appa-
ratus be supposed to revolve, until A reaches L. During
this time B travels from L to M ; C from M to N ; D from
N to O 5 E from O to P ; F from P to Q ; G from Q to E ;
and H from E to K. Thus, through the passage of A from
K to L, in other words during the rotation of the apparatus
through one-eighth of a revolution, every point on the horizon
is once illuminated.
164 EUROPEAN LIGHT-HOUSE SYSTEMS.
"If the flame continue burning, the same effect is pro-
duced during every succeeding eighth of a revolution.
Every point of the horizon is once illuminated. At Eocka-
bill the time of a complete revolution is ninety-six seconds ;
hence, the number of panels being eight, as in the model,
each point of the horizon receives flashes which succeed
each other in intervals of twelve seconds.
u But suppose at the moment the beam A points toward
L the supply of gas to be cut off, and the apparatus per-
mitted to revolve in darkness until A reaches M. During
this eighth of a revolution no gas is consumed, and no flash
is received by any point on the horizon.
" When A reaches M let the gas be relighted. During
the succeeding eighth of a revolution every point of the
horizon would be once illuminated as before. It is quite
manifest that this process may be continued indefinitely ;
the gas being lighted and every point of the horizon once
illuminated during every alternate eighth of a revolution.
" It is also plain that the intervals of darkness between
the flashes instead of being, as they now are, twelve seconds,
would be twenty-four seconds. This reasoning, which as
far as it goes is of the character of a mathematical demon-
stration, has, as stated in my report of the 8th of October,
been verified by actual observations on the Eockabill light.
" There is, as far as I can see, but one drawback to the
perfection of this scheme ; and this I will now try to point
out with distinctness. Let the beam A point, as at the
outset, toward K ; at a certain moment we start from K
toward L with the gas lighted. According to the new scheme
K ought to be in absolute darkness for twenty-four seconds.
But just as A reaches L, and before the gas is cut off, a
glimmer is seen at K, this glimmer being only twelve sec-
onds distant from the preceding flash. The same is true of
the other seven points of the horizon faced by the panels the
moment before the flame is extinguished. In all the remain-
ing sweep of the horizon this secondary glimmer is absent."
Professor Tyndall further says in regard to this glimmer
that he noticed it in his experiments at Eockabill light-
house, but attached no practical importance to it; and that
on the isolated points where it is seen it is so masked by the
superior brilliancy of the true flash that no mariner could
be deceived by it.
substitution of The same method of substituting an oil-lamp for the gas-
burner? 's burner is arranged for intermittent as for fixed lights, the
only difference being that if the oil-lamp were used the
machine which actuates the cutting off of the gas is made
o il
THE IRISH GAS LIGHT.
108 JET BURNER.
SECTION.
PLATE XX VII. -
o. o. 1O8
Tubes.
4 Inches to 1 Poot.
EUROPEAN LIGHT-HOUSE SYSTEMS. 165
to open and shut semi-cylindrical shades for eclipsing the
oil-lamp for the required period of darkness. As in the
case of Howth Baily, no occasion has ever arisen at Wick-
low for falling back upon the oil-lamp since gas was lighted
at that station, about seven years ago. The advantage of U8td0Vfa^ntfrnn°tf
the use of intermittent lights as applied to gas light-houses tent nght-
is obvious, for during the period of darkness the consump-
tion of gas is saved, whereas in the case of oil-lights, the
flames of which are merely eclipsed by shade, the consump-
tion of oil continues during the intervals of darkness as
well as during the intervals of light. This peculiarity of
gas renders its use for intermittent light still more economi-
cal than for fixed lights. All the four/o#-powers of the gas-
burner may be intermitted precisely as is the case with the
first or ordinary power.
By the use of gas in an intermittent-light apparatus there
is no occasion to alter the existing lenses.
REVOLVING GAS-LIGHTS.
The burner used in this case is precisely the same as that Burners.
in the fixed and intermittent lights. The lenses by which Revolution of
the flashes are directed to the observer revolve around the lei
gas-light just as they revolve around the oil-light. An
arrangement similar to that in fixed lights for substituting
the oil-lamps for the gas-burner is also established. The
remarks as to the superiority of gas over oil in fixed lights
apply equally to revolving lights, with this additional advan-
tage, that by the use of gas-burners whioh have large diame-
ters each flash is of longer duration than in the case of the
oil-lamp, and this is stated to have been highly appreciated
by mariners.
GROUP-FLASHING GAS-LIGHTS.
The burner used in this cassis precisely the same as that Burner,
in fixed lights. The groups of flashes are caused by the con- Flashes.
tinual extinction and re-ignition of the gas-flame. This is
accomplished by similar means to that which causes the in-
termission of a fixed light, except that the machinery which
causes the lenses to revolve is availed of for actuating the
cutting-off gas- valves instead of a special machine being
provided for that purpose. By means of this system of
group-flashing the same economy may be attained which
the use of gas presents in the case of intermittent lights, with
this difference, that the economy is always at a fixed ratio,
viz, about one-half the consumption of the gas. The lenses
are continually revolving and the gas-light is continually in-
termitting. By reducing the speed of the revolutions of the
16G EUROPEAN LIGHT-HOUSE SYSTEMS.
lenses (which themselves require no alteration for this sys-
tem) a group of seven or eight distinct and powerful flashes
recurring at regular intervals may be obtained, and the effect
of this kind of light is said to be exceedingly arresting to
the eye of the mariner.
TRIFORM FIXED GAS-LIGHT.
Three burners This light is produced by three burners similar to that
above described, placed vertically over each other as shown
Air-chambers in Plate XXIX, but the two upper burners are surrounded by
ers. "r n two air-chambers for the supply of pure air to the flame and
the carrying off of the foul air from the flame of the burner
below. Tubes for the introduction of pure air are placed
obliquely in these chambers, and the effect of the arrange-
ment is that not only are these three burners of equal power
when in a light-house lantern in place of one as in an ordi-
nary case, but the light is much intensified by the manner
in which the burners are supplied with heated air.
Description of In the plate, a is the main supply-pipe, &, &', ~b" are the gas-
burners, c, c' are the distributing-pipes, d, d', d" ;ire the mica
chimneys, e, e', e" are the sheet-iron chimneys,/, /' are the
outer air-chambers, ft, li1 are flues leading to the inner
air-chambers </, g', which at their lower ends have the form
of inverted cones ; * is the main escape pipe, and fc, ft, ft are
the refracting belts.
Removal of top The top and bottom prisms of the dioptric apparatus are
and bottom
prisms. removed, and instead of them segments of refracting belts
are placed above and below the central belt of the dioptric
apparatus. (See Fig. 1, Plate XXX.)
Amount of gas The consumption of gas in this form of apparatus is three
consumed. ^m^ that of the single lamp, but the quantity of light is
more than three times as great. We must, however, deduct
the light which would be transmitted from the top and bot-
tom prisms of the single lamp apparatus, which is valued at
about one-third of the whole apparatus, and it may be said
that the light of a light-house illuminated by the triform
Ratio of iiiu- apparatus is to that of a light-house illuminated by a single
a^uced^trfform lamp and an ordinary lenticular apparatus as 2 to 1. It
light and 8inglewjllbeseen by the tabie of photometric values that the
power of the largest size of the gas-burner is stated by Mr.
Wigham to be equal to 2,577 candles. Assuming this to be
correct, there is therefore transmitted by means of triform
apparatus three times that amount, viz, light equal to 7,731
candles, and if this is increased more than eighteen times
by the agency of the cyliudric refractors, as is the case
EUROPEAN LIGHT-HOUSE SYSTEMS. 167
where the ordinary oil-burner is used in a first-order fixed
lens, the immense power of more than 139,158 candles is
transmitted to the observer. This power, great as it is, is
of course exceeded by the triform light in revolving ap-
paratus.
TRIFORM INTERMITTENT GAS-LIGHT.
The apparatus in this case is precisely similar to that
described for intermittent lights with one lamp, except that
refracting belts are substituted for top and bottom prisms
as described in the case of the triform gas-apparatus for
fixed lights.
TRIFORM REVOLVING GAS-LIGHTS.
The arrangements of burners, lenses, &c., are nearly similar of
to those for fixed lights. The lenses are placed vertically es, &c.
(see Fig. 2, Plate XXX) in order to give the most power-
ful beam that can be transmitted to the horizon, but in case
it were desired that the ordinary flash should recur more
frequently than is possible with an apparatus containing
only one light, the lenses may be placed eccentrically, as
shown in Fig. 3, Plate XXX, and this in a very striking
manner attains that object.
TRIFORM GROUP-FLASHING LIGHT.
The remarks made under the head of group-flashing light
for a single lamp apply equally in this case, but the groups
of flashes proceed from three lenses in place of one, and are
consequently of much greater power.
EXPERIMENTS WITH THE TRIFORM LIGHT.
On. the evening of our return from Howth Baily to Dub-
lin we proceeded to a point near Kingstown, on the south
side of Dublin Bay, distant six miles from the Howth Baily
fixed gas-light, to observe some experiments to be made Experimental
with a triform light, (previously placed temporarily, for pur- tw™eif fixed ami
poses of experiments made under direction of Professor ngii£s0rm gai
Tyndall, in a small cabin near Howth Baily light,) arrange-
ments for which had been made by Captain Hawes and Mr.
Wigham while we were at that station.
The three Wigham burners, each capable of burning from Arrangements
28 to 108 jets, were placed vertically over each other in the
foci of three panels of the refracting belt of a first-order lens,
as already described, stop-cocks being provided, so that any Manner of in-
of the rings of either burner could be lighted or extinguished creasing light!*6"
168 EUROPEAN LIGHT-HOUSE SYSTEMS.
at pleasure. The principal keeper at the station had re-
ceived instructions to cover and uncover the catadioptric
prisms of the first-order lens in the tower, while the assist-
ant was to vary the powers of the triform lights, both act-
ing according to a memorandum given to each, a copy of
which we were provided with.
Programme of experiments with a triform light at Howth Bally, Dublin
Bay, August 6, 1873.
Tower lights.
Triform lights.
P.M.
9. 30. — 28 jets ; cover the catadioptric prisms . . .
9. 35.— 28 jets ; uncover catadioptric prisms
9. 40. — 28 jets ; catadioptric prisms uncovered . .
9. 45. — 28 jets ; catadioptric prisms uncovered . .
9. 50.— 28 jets ; catadioptric prisms uncovered . .
9. 55. — 108 jets ; catadioptric prisms uncovered .
10. 00. — 28 jets ; catadioptric prisms uncovered . .
10. 05. — End of experiments.
P.M.
9. 30.— 28 lets ; upper belt only.
9. 35.— 28 jets ; the three belts.
9. 40.— 48 jets ; the three belts.
9.45.— 68 jets ; the three belts.
9. 50.— 88 jets ; the three belts.
9. 55.— 108 lets : the three belts.
10. 00.— 108 jets ; the three belts.
Appearance of From our point of observation at Kingstown the 28-jet
light, shown only in the upper belt of the triform arrange-
ment, appeared slightly inferior to the 28-jet light in the
tower when the catadioptric prisms were covered. They
should have appeared equal, but the difference is accounted
Reason for in- for by the facts that the ventilation of the cabin and the
ngh°triburninf ^n °^ refracting belts used for the experiments were imperfect,
the?rifoermbappa-an(i neitoer tne latter nor the glazing of the window were
ratus. so ciear as jn the lantern of the tower-light.
When the catadioptric prisms of the tower-light were
uncovered and the entire beam from the lens thus coming
to our view was compared with the triform lights, changed,
Su eriority ofas snown *n ^ne table, from 84 to 324 jets, the superiority
the triform-light, of the latter was very marked, it having the appearance of
a great globe shining with a pure and dazzling white light.
The effect of the changes in the triform light was peculiar,
and one could hardly believe that he was observing two
lights equally distant from him, for, as the power of this
light was gradually increased, the one in the tower appeared
rapidly to recede and to be thrown further and further
to the rear, so that when 108 jets burned simultaneously
behind each of the refracting belts, the tower-light, burning
28 jets and equal in power to an ordinary first-order oil-
light, appeared to have receded many miles, and to have
dwindled until it presented the appearance of a star.
When 108 jets were burning in the tower the comparison
with the triform light of 324 jets was still very much in
favor of the latter, though the superiority was not so
marked.
THE IRISH GAS-LIGHT.
PLATE XXVII I,
28-JET BURNER.
EUROPEAN LIGHT-HOUSE SYSTEMS.
169
It may be well to state that the columnar form which the Form of the
triform light like
triform light might be supposed to assume is not observ- the other in ap-
able, as from Kingstown it appeared to us of precisely the pe
same shape as the single light in the tower.
ILLUMINATING POWERS OF GAS-LIGHTS.
The following are the results of observations recently
made with a photometer, as stated to me by Mr. Wigham :
Gas-burn-
Consumption
Illuminating power,
the unit being a
ers — No. of
in cubic feet
sperm candle, con-
jets.
per hour.
suming 120 grains
per hour.
28
50
330. 68
48
100
668.28
68
150
1, 002. 09
88
220
1, 667. 49
108
290
2,577.3
Additional
In this connection it should be observed that Trinity illuminating
House four- wick oil-lamp, as improved by Mr. Douglass,
consuming 34.13 ounces per hour, (160 ounces to the impe-
rial gallon,) gives an illuminating power equal to 328.18
sperm- candles.
According to actual experiments, the first-order fixed
dioptric apparatus transmits to the mariner 27.39 times, and
the first-order revolving apparatus of eight panels 338.74 paBytU8revoMng
times, more light than the unassisted first-order oil-lamp. appar
These ratios would give for single lenses illuminated by Wig-
ham's gas-burners of 108 jets powers, equal respectively to
70,592 and to 873,034 candles. It is stated (see M. Reynaud's
Memoire sur Vlficlairage des Cotes de France) that the lumi-
nous beams from the refracting belt ' of a dioptric appa- Power
ratus for a fixed light of the first order is .7 of the firTt-o?!
beam from the entire lens, and that the beam from the
refracting portion of one of the panels of a revolving octag-
onal lens of the first order is .647 of the entire beam ; also
that in the first case the power of the refracting portion
of the lens is 19.13, and in the last case 218.1 times more
powerful than the unassisted first-order oil-lamp. The
same ratios for triform lights, supposing each lamp to burn
108 jets, would give for the fixed light 147,914 candles, and
for the revolving light 1,686,228 candles ! I am not aware The above re-
that any experiments have been made of the actual powers inpracSce,owing
of lenses illuminated by gas-lights, but as a considerable %
of
fixed.
Revolving.
Ratios applied
to triform lights.
170
EUROPEAN LIGHT-HOUSE SYSTEMS.
portion of the light is exfocal, the divergence is so much
increased that the above results would be very far from
holding good in practice.
Results arrived I should further add in regard to photometric experi-
at bv Professor , -IT TUT- i •> i
Tyndaii on ex- mental comparison between oil and Wigham's gas-burners
for light-houses that Professor Tyndall arrived at the fol-
lowing results :
(The four-wick lamp being taken as the unit, the illumi-
nating power of the gas-flame is expressed in terms of that
unit. )
Four-wick
lamp.
Number of
jets.
Gas-flame.
28
2*
48
41
68
6
88
9f
108
13
That is to say, the photometer showed the 28-jet flame to
have two and one-half times, the 48-jet flame four and one-
half times, the 68-jet flame six times, the 88-jet flame nine
and three-fourths times, and the 108-jet flame thirteen times
the illuminating power of a four-wick flame of a first-order
sea-coast light-house lamp.
The above ex- It should be mentioned in this connection that these ex-
periments ante- , , . , . . ,
nor to recent penments were probably made anterior to the improvement
iSpSmers!8 in in oil-lamps made by Mr. Douglass, the present power of
his four-wick lamp as compared with the lamp formerly
used being as 328 to 2G9.
COST OF WIGHAM'S GAS-LIGHT APPARATUS FOR LIGHT-
HOUSES.
Costofappara- Mr. Wigham informed me that the cost of gas-making
shipmSJand d°er apparatus of a size similar to that used at the Irish stations,
Liver- Eockabill> Wicklow Head? Hook i>Ower, and Mineheacl,
packed and delivered at Liverpool ready for shipment,
would be, for a single tower, about £1,000, ($5,000,) and for
Resulting cost a station with two towers, like that at Cape Ann or High-
ifgbKfclpe lands of Navesink, about £1,600, ($8,000.) These esti-
Arm, or Nave- mates inciucie furnaces, retorts, gas-holders, and tanks for
the same, together with the burners and every other item
of expense except the freight from Liverpool to America,
the cost of erection at the site, and the additional buildings
EUROPEAN LIGHT-HOUSE SYSTEMS. 171
required. The expense of the latter item is, in Ireland, Expense of
about £250, ($1,250,) and in the United States would bebu
somewhat larger hi consequence of the higher price of labor.
Mr. Wigham further stated that he would personally in- w£^di^n *w?*
spect any site at which the United States Government ham yould con-
J sent to erect a
might desire to use his apparatus, and give the Board all gas-light appara-
tus in the United
the information and assistance in his power, on condition states.
that his traveling and other expenses be paid; also that he
would bring with him for the purpose of assisting in and
superintending the erection of the entire work, one of his
most competent foremen, the charge for whose time would
be 10s. 6d. ($2.62) per day in addition to his expenses for
board, lodging, and traveling.
In regard to the use of his gas-light in the United States
Mr. Wigham stated that although his patent did not extend
to this country he would have no hesitation in building a
gas-light for our use, having no fear but that, should others
be required, his labors for the improvement of light-house
illumination would be recognized and rewarded.
COST OF THE TRIFORM-LIGHT APPARATUS.
The cost of this gas-apparatus is greater by about £250 Cost of triform
($1,250) than for the ordinary single-light apparatus.
The expense of removing the upper and lower catadiop-.
tric prisms of the lens and substituting for them two refract- paratnfo the
ing belts is in Ireland not great, as Chance, Brothers & Co., r
who supply most of the lenticular apparatus for the British
lights, offer to take the prisms of the first-order lens in ex-
change for refractors on payment of a difference of £150,
($750,) provided the prisms are of their own manufacture.
If a new light-house were building, or if a new dioptric
Cost of placing
apparatus were to be placed in an existing light-house, it triform lens-ap-
.. , parutus less than
would be rather less expensive to have it arranged on the that of the or<u-
triform system than in the ordinary way, with a central beltna
and upper and lower catatlioptric prisms.
COST OF MAINTENANCE OF GAS-LIGHTS.
The use of tar for fuel in Great Britain within the last Use of tar for
few years has so lessened the cost of production of gas that
it may be calculated, it is stated, not to exceed, even at out-
lying stations, 10s. ($2.50) per thousand feet, including 4 per
cent, interest on the original outlay for apparatus.
If gas could be supplied to our light-houses at this rate Approximate
} animal cost of
the cost per annum to a first-order seacoast-light, burning gas-
habitually 28jets during the average period of illumination,
172 EUROPEAN LIGHT-HOUSE SYSTEMS.
(4,311 hours,) would be $550 ; adding for ail extreme case (as
West Quoddy Head on the coast of Maine for example) 20
per cent, for additional consumption in foggy and thick
weather, we have $660 as the approximate annual cost of
the gas for such light,
cost of annual The annual consumption of oil in our light-houses of the
consumption Of flrgt Qrder ig &^Qut 7QQ gSL\\oll^ amounting at the last aver-
age contract-price of 89 cents per gallon to $676.40.
Less cost for At stations with two towers the cost per thousand feet is
§jetpat tstSns considerably less than at single tower-stations, since the cost
SSuawhere^re^ the labor and other items is proportionately less the
is but one. greater the quantity manufactured.
ILLUMINATION OF BEACONS BY GAS.
Beacons on out- Mr. Wighani has devised an arrangement for lighting by
lying rocks. g^ beacons on detached rocks which are inaccessible dur-
ing heavy weather. Gas for the illumination of such posi-
tions cannot ordinarily be carried in submarine pipes, on
account of the condensation of moisture within the pipe,
the lowest part thus becoming filled with water and the
flow of gas being consequently obstructed,
prying gas Mr. WighanVs plan is to dry the gas by chloride of cal-
with chloride of. ,, TIJ T J-TI j.» • i
calcium. cium, and he proposes to light and practically extinguish
the beacon by means of variations of the pressure of gas in
the supply -pipe ; that is to say, a high pressure of gas, say
of six inches of water, closes a stop-cock at the beacon and
keeps it closed during the day; at the time of lighting, this
pressure is decreased to the ordinary working-pressure of,
say, three inches of water, and the cock opens. The burner
is lighted by means of a little flame supported by a small
" by-pass," such as preserves the light from extinguishment
during eclipses at the Wicklow Head intermittent light
heretofore described. The full power of the light can be
kept up till sunrise, when the increased pressure of gas closes
the cock arid extinguishes the beacon.
The invention Experiments sufficient for determining the utility of this
not yet tuiiy test- .nveil||OI1 nave not ye^ been made ; but it seems a step in
the right direction, and affords another indication of the in-
genuity of Mr. Wighani.
opinions of the I11 concluding my remarks on the subject of gas as an
ot ^^minant for light-houses, I will only say that the Irish
Board and its officers state most positively that the actual
use of gas at five of its sea-coast stations proves it to be
Annual saying more economical than oil, and specifically, at Howth Baily
atHowthBaiiy. the gaving ja £50 ($250) annually, taking into account all
THE IRISH GAS-LIGHT.
TRIFORM BURNERS.
PLATEXXIX.
_Znc/ieSi2 9 6 3 O
SCALE .
- Feet.
EUROPEAN LIGHT-HOUSE SYSTEMS. 173
expenses of making gas and the interest on the first cost of
apparatus.
Professor Tyndall states that the 28-jet burner, the lowest Opinion of pro-
7 . _ . . fessor Tyndall as
power of the gas-lamp, gives a light in no degree inferior to to the compara-
the first-order four-wick oil-lamp used in light-houses. and wi7ights.gas
The oil-lamp is susceptible of few variations in regard to variability in
regard to power
power, (our lamps have none : the Douglass six-wick lamp not possessed by
* oil-lamps, except
used by the Trinity House has three, and the power of the those of Mr.
light can be increased from 324 to 722 caudles;) while the patent!88
gas-light of the triform system can be carried through
many more gradations reckoning from the lowest,* so that
a skillful keeper can suit his light to any condition of the
atmosphere.
Assuming the facts to be as stated by Professor Tyndall, Either the four-
either the four-wick oil-lamp or theWigham 28-jet gas-lamp a&jet a sufficient
are sufficient in clear weather to send their rays from the fairweather.
lanterns of sea-coast towers to the sea-horizon a distance of
twenty miles.
As has been stated in speaking of Haisborough, no light
which has been or ever can be invented can be seen through
a dense fog, which obscures even the sun itself.
It will be seen, therefore, that the required improveme
in sea-coast lights is that of a varying capacity of power po
that can be suited to all stages of the atmosphere, and the weather.
Irish gas-light certainly appears to me to meet this require-
ment more fully than any other known, with this additional Additional ad-
advantage: during the eclipses of revolving and intermit- omyaine flashing
tent lights the consumption of the illuminant may be en- ga
tirely suspended, and when, as is often the case, the total
amount of eclipses is six hours or more out of twelve, the
economy is evident,
Professor Tyndall, in one of his reports to the Board of
Trade, thus sums up his conclusions :
" The results assure me that with gas as a source of illumi- Conclusion of
. , , Professor Tyn-
nation an amount of variableness and consequent distinct- daii.
iveness is attainable which is not attainable with any kind
of oil. It would, I think, be easy to give to every light-
house supplied with gas so marked a character that a
mariner on nearing the light should know with infallible
certainty its name.
" As stated in a former report, I look in great part to the
flexibility with which gas lends itself to the purposes of a
signal-light for its future usefulness.
* It has been calculated that the actual number of possible gradations
is 155, although in practice not more than fifteen would probably be
made.
174 EUROPEAN LIGHT-HOUSE SYSTEMS.
" It may be beaten iii point of cheapness by the mineral-
oil now coming into use, (that is to be proved ;) but in point
of handiness, distiuctiveness, and power of variability to
meet the changes of the weather, it will maintain its supe-
riority over all oils."
WIGHAM'S GAS-GUN FOR FOG-SIGNALS.
Gas-gun for use Mr. Wighain has also invented a gas-gun, to be used as
-signal. a f0g_sjgnaj at Cations illuminated by gas 5 and I had an
opportunity of testing it, both at the manufactory in Dub-
lin and at Howth Baily light-station. Captain Hawes
kindly directed that the gun should be fired during our
observation of the triform-light from Kingstown, so that, at
a distance of six miles, I could judge of its efficiency as a
signal.
construction of The gun is simply a tube of iron connected with the gas-
holder by a halt-inch pipe; in fact, in these experiments the
guns were nothing more than pieces of ordinary gas or
charge. water-pipe of different diameters. The charge of the gun
is a mixture of oxygen, coal-gas, and common air, one-
fourth of the mixture being common air and the, remainder
composed of equal volumes of oxygen and ordinary illu-
minating gas.
Manner of fill- The proper quantities of the gases are allowed to flow
mg the gun. from their respective reservoirs into a holder, and the mix-
ture is thence transferred to the closed end of the pipe or
breech of the "gun,'7 the flow being regulated by a stop-
cock. The mixture is lighter than common air, and when
it fills the feed-pipe and gun, the latter being lower than
the source of supply, it will remain charged or full until
tired, which may be done by touching a match to an orifice
at any point of the connecting-pipe desired, taking care
that communication with the holder is closed by the stop-
cock.
Product of the The product of the explosion is carbonic acid gas and
water, and, as the latter would rapidly fill any part of the
feed-pipe which might be lower than the gun, it would
probably be a fatal objection to the use of the invention
which immediately suggests itself, viz, its application as a
fog- signal on outlying rocks difficult to approach or nearly
submerged. The defect is all the more to be regretted, as
it is at precisely these points that fog-signals are most
needed and the erection of other kinds is impracticable.
At Mr. Wigham's extensive works at Dublin the feed-
pipe was several hundred feet long.
oo,
n
li
O V)
a
00.
n
°;
EUROPEAN LIGHT-HOUSE SYSTEMS. 175
The use of the gun at any gas-light station would be simplicity of
the signal.
extremely simple, and the keeper need not go to the gun
itself, but could easily fire it from his watch-room at the
required intervals. I do not know that the experiment has Suggestion that
the gun might be
even been tried, but it will readily be seen that by using fired by electric
the electric spark the service of the gun might be made
still easier, for a system of clock-work connected with a
battery could be easily devised by which an electric circuit
could be formed and a spark produced at any desired in-
terval, and thus the gun be fired without any attention on
the part of the keeper except what might be required to
keep the apparatus in order.
At Howth Baily the guns were twelve inches in diameter Description of
guns at HowtQ
and from six to nine feet long. The latter were duplicated,
and consisted of two connected pipes, fired simultaneously.
Near at hand the reports seemed loud and clear, but whenlo^ear reP°rt
heard from Kingstown a high wind prevailed over Dublin
Bay, and I was disappointed in the results. It is true that
the distance was six miles, and a comparison with other
signals would have been more satisfactory, but I fancied superiority of
that the 18-pounder fog-signal gun at North Stack, on the gune at8 North
other side of the channel, would have been more distinctly st
heard under the same circumstances.
The flash from this gun is said to illuminate fog much illumination
better than that from a gunpowder-gun. S^6
I have no doubt of the utility of the invention for fog
signals at stations illuminated by gas, if the very great
expense attending the manufacture of oxygen can be over-
come; and, as Professor Tyndall is now charged by the
Board of Trade with the conduct of a complete series of ex-
periments with the gas-gun, it is to be hoped that the in-
ventive genius of Mr. Wigham will overcome all objections
to which it may now be subject.
In concluding my observations on Irish lights I must ex-
press sincere thanks to the commissioners and to Captain
Hawes, the very intelligent inspector of lights, as well as
to Mr. Lees, the secretary of the board, and to Mr. Wigham,
for the pleasure and instruction I derived during my limited
sojourn in Ireland.
SCOTTISH LIGHTS.
From Dublin I proceeded to Belfast by rail ; thence by
steamer to Glasgow, and by rail again to Edinburgh.
Immediately on my arrival I called at the office of the Com- Visit to Com-
missioners of
missiouers of Northern Lights, and introduced myself to Mr. Northern Lights
176 EUROPEAN LIGHT-HOUSE SYSTEMS.
Alexander Cunningham, for many years the secretary of
the Commission, who received me with great cordiality, and
with whom I had an interesting conversation concerning
the Scottish system of light-house administration, and
especially in regard to the appointment, payment, and regu-
lations affecting the keepers of the northern lights. The
Regulations, regulations are quite severe, and for any neglect of duty or
other misconduct the keeper is peremptorily dismissed or
otherwise punished, and a printed circular, advising keepers
of the facts in the case, is at once sent to all the stations in
the service. The warnings thus received tend greatly to
promote the efficiency and good management of the lights.
The following extracts from the regulations of the Scot-
tish light-house service will give an idea of the great care
that is taken to promote the interests of the keepers and
to secure efficient lights.
Appointment of All light-keepers are appointed by the Board, after an
examination in reading, writing, and arithmetic, and a pro-
bation of three months' instruction at light-houses, (viz, six
weeks in a dioptric or lens light-house, and six weeks in a
catoptric or reflector light-house.)
instruction of While on probation the a expectant " is carefully instructed
keeper!.0 tant by ^e principal keeper of the light-house where he is as-
signed, cautioned as to the responsibility he is undertaking,
and the invariable rule of the board, that if he goes to sleep
at his post he cannot be admitted into the service.
He is specially instructed in the management of the lamp,
cleaning the lenses and mirrors, and in taking apart and
re-adjusting the various machinery. He makes the monthly
returns, and keeps the books of the station while there.
At the expiration of his term of instruction the principal
keeper certifies to his competency, or gives reasons for not
doing so. If found competent, he is appointed when a
vacancy occurs.
The following are the ordinary rates of pay allowed to
keepers :
Term of service.
Principal
keeper.
Assistant
keeper.
Under 5 years' service .
Per annum.
£56, ($260)
Per annum.
£44 ($220)
Abnvpi 5 and under 10 years' service
£58 ($590)
£46 ($230)
A br>vp 1 0 years' service .
£62, ($310)
£48, ($240)
Additional pay is given for rock and other detached sta-
tions, in some cases as much as £20 ($100) per year.
EUROPEAN LIGHT-HOUSE SYSTEMS.
177
Pensions.
Each keeper has a furnished house, with annual supplies of Dwelling and
coal and oil, and where no land is attached to the station an ai
allowance of £10 (-$50) per annum is made. They have also
an allowance for washing and for expenses when traveling
on public service. They are uniformed at public expense.
Three pounds ($15) per annum is retained from the salaries
of each and applied toward effecting an insurance on their
lives.
Retiring pensions are allowed, and gratuities if they are
constrained to quit the service before being entitled to a
pension by reason of injury sustained in the discharge of
duty or from other infirmity of mind or body.
The ground attached to light-houses is carefully culti-
vated and turned to the best account, and the growing crops
are transferred when one keeper relieves another.
Light -keepers at rock-stations are allowed daily rations,
as follows :
One pound of butcher-meat.
One pound of bread.
Two ounces of oatmeal.
Two ounces of barley.
Two ounces of butter.
One quart of beer.
Vegetables when procurable.
For tea, sugar, salt, and other table necessaries, 4rf. per day.
The light-houses are arranged in groups, and each group
is supplied with a moderate amount of current literature
and periodicals, which circulate in the group, remaining a
specified time at each station, and afterward are bound and
form part of the library of the last station. Each light-house
is in turn.the last of ics group, so as to give each station its
fair share of books. The Weekly Scotsman and the Il-
lustrated London News are sent to each light-house.
An ordained clergyman of the Church of Scotland is ap-
pointed to visit annually those remote stations where keep-
ers and their families cannot attend divine worship. He
remains about two weeks at each station conducting divine
service and instructing the children at the station in ordi-
nary branches of education as well as in their religious duties
It is recommended by the Commissioners that each light-
keeper or his wife spend some time daily teaching their
children after the clergyman leaves, and when he returns
the following year he examines the children as to their pro-
gress.
Medical attendants are also appointed for remote stations,
S. Ex. 54 12
Libraries.
Attendance of
clergyman.
Medical attend-
ants.
178 EUROPEAN LIGHT-HOUSE SYSTEMS.
and are allowed a fixed sum per annum, exclusive of the fees,
paid by the keepers.
They are to attend on the keepers, who pay them a fixed
fee for each visit. Medicines and medical instructions are
furnished each station.
Report or quai- Keepers are required to report annually the quality of the
ce!ved.8t< esre~ stores received after a trial of them in detail. A special.
Test of oil. tr|a] ig ma(je Of the Oii for ten nights from December 1 to 10 ;
the result of each night's trial is noted on a for.n prepared
for that purpose and finally reported to the Board,
p recant ions Special precaution s are taken with mineral-oil. The tanks
with mineral-oil.
have tight-fitting covers, and the oil is tested in the presence
of the keepers to ascertain that theflashing-pointis not below
120° Fahrenheit. In addition to this the keeper is required
to test it before commencing to use out of a new tank.
Appointment of For each station a person resident near the light-house is
iightkeepers.a appointed an "occasional " light-keeper, and is required to
attend the station whenever required by the regular keepers.
They are regularly trained, are under the supervision of the
commissioners, and are allowed regular rates for each day's
attendance at the station. They are obliged to attend the
light at least twenty nights per annum in order to keep in
practice.
Boatman for At each island-station a boatman is appointed and paid
either a fixed salary per annum 'or a certain rate per trip,
and when he has no boat of his own, the Commissioners
furnish one. He is obliged to make at least four trips to
the light-house every month, and to visit it whenever sig-
naled.
sketch of the The "Board of Commissioners for Northern Lights" was
om"established in 1798. Up to that time the Trinity House
exercised direct control over the Scottish lights, and it does
so now in some small degree. The Commissioners receive
no salary. They are all ex-officio members, viz, the Lord-
Advocate and Solicitor-General of Scotland, the chief mu-
nicipal authority (whether Lord Provost or Senior Bailie)
of Edinburgh, Glasgow, Aberdeen, Inverness, Campbell-
town, Dundee, Leith, and Greenock, and the sheriffs of the
maritime counties of Scotland. The committees of the
Board meet twice a month, but the entire executive func-
tions are exercised by the secretary and engineers.
The latter are Messrs. David and Thomas Stevenson,
whose published writings on light-houses and their illumi-
nation have not only given them a world-wide fame, but
have established the reputation of the light-house system
EUROPEAN LIGHT-HOUSE SYSTEMS. 179
of Scotland as second to none bat that of France, which is
acknowledged to be the model for all others.
Both were unfortunately absent the first morning I called,
and I took the opportunity of seeing somewhat of Edin-
burgh, which, I think, is justly called the most picturesque
city of Europe.
As I found I would have sufficient time, I made a quick
journey to Stirling Castle, Loch Lomond, Loch Katrine, and
the Trossachs. On my return, I had the pleasure of meet-
ing Mr. Thomas Stevenson, and had a prolonged and inter-
esting conversation with him, gathering much information
on subjects connected with the object of my visit. He
showed me a reflector for light-houses, which was made
after designs of his grandfather nearly a century ago. The
interior reflecting-surface is composed of little facets of
mirror-glass set into a paraboloidal form, and it is appar-
ently as bright and useful to-day as when it was new, show-
ing that such reflectors, which suffer no wearing of the sur-
face by polishing, are very durable. In the opinion of Mr.
Stevenson the silvered copper reflectors, which depend for
their efficiency on the polish given them by the keepers,
are really no improvement, they having no advantage over
those previously used. Mr. Stevenson has invented a new
form for harbor and ships7 lights, which he calls the differ- Differential re-
ential reflector, in which the vertical sections are parabolic
and the horizontal elliptical ; and he showed me a model.
None of this kind, however, had been made for service.
He also showed me models illustrating the use of dioptric
lights in light-ships ; also his holophote, hemispherical diop-
tric mirror of total reflection, and holophone or sound re-
flector. The latter is shown in Figs. 20 and 21, and Mr. stevensou'H
Stevenson kindly promised to send me a model of the lat- sound-reflector.
ter as soon as the mechanics employed by the Board could
find time to make it, (I have since learned that it is en route,
having been sent according to promise,) so that from it a
fog-signal reflector can be made for actual trial in our
experiments.
In regard to reflectors for fog-signals, Mr. Stevenson con-
firmed the opinion entertained by Professor Henry, that if
they are of metal they should be covered with plaster or
some other substance to prevent vibration; also, that wooden
surfaces would be as efficient reflectors as any others. This
would enable us to construct a holophone cheaply and ex-
peditiously, if it should be desired to use one in our experi-
ments.
180
EUROPEAN LIGHT-HOUSE SYSTEMS.
Mr. Stevenson is the inventor of several important modi-
fications in the form of dioptric apparatus for light-houses,
and at the time of my visit, the Northern Lights Board oc-
cupied a large space in the industrial exhibition at Edin-
burgh, having an exceedingly full and interesting display
of illuminating-apparatus, and of models of some of Scot-
land's famous light-houses, including Skerryvore and the
Bell, or Inch Cape Eock. Among other interesting objects
Apparatus for I noticed a fixed azimuthal condensing-apparatus, designed
fintre-liffhts. ,, ,, , ,. „
for " leading," or, as we say, " range" lights, for the river Tay.
It collects the rays of the lamp and distributes them equally
over an angular space of 45°, and combines for this purpose
five optical agents, viz, Fresuel's fixed light-apparatus, Ste-
venson's condensing prisms, a half holophote, right-angled
conoid al prisms, and a hemispherical mirror of totally re-
flecting prisms.
Fig. 20.
Fig. 21.
range-lights.
Vertical section of holophone. Front elevation of holophone.
There was also on exhibition a model of a light-house
ot Mr. stevenson. lantern with diagonal sash-bars, the placard of which stated
that the first lantern of that description was constructed
by Mr. Stevenson in 183G.
Mr. Stevenson remarked, in regard to fog-signals, that
the Board have none operated by steam, but that bells are
placed wherever they are useful. The only instance in
Scotland of a steam oi1 hot-air fog-signal is in the river
Clyde, and it is maintained by a steamship company ; yet
the coasts of Scotland are habitually foggy at some seasons
Diagonal sash-
bars ail invention
Fog-signals.
EUROPEAN LIGHT-HOUSE SYSTEMS. 181
of the year, being, I infer, as unfortunate in this respect as
our northern Atlantic or our Pacific coasts.
Neither have the Scottish Board any light-ships, nor in-
deed is there any occasion for them, the coast being every-
where abrupt with no outlying shoals or reefs. Mr. Steven-
son gave as his opinion, derived from observations, that re-
volving lights should be used as much as practicable for
light-ships, for the reason that they have a greater range of
visibility than fixed lights.
Messrs. Stevenson and Cunningham confirmed the state- Adoption of the
ment made to me by Captain Doty in London, viz, that the P^1^^
mineral oil lamp invented by the latter had been adopted Jj^J.0 Board ot>
by the Scottish Board, subject to the approval of the Board
of Trade, and with the understanding that he should receive
as remuneration for his patent the saving effected in one
year at each light-house where it might be introduced. At
the time of my visit, however, it had been actually intro-
duced into but five light-houses, as the Board of Trade hesi-
tated at the terms of Doty's offer, which would give him
for the use of his patent about £75 ($375) for each first-
order light-house, and proportional amounts for smaller
lights. The Board of Trade, acting under the advice of
Trinity House, directed that the substitution of mineral for
colza oil in Scotch light-houses should be deferred until the
experiments on the relative values of the Trinity House
(Douglass) and the Doty lamps should be completed; in
order, I presume, to avoid paying a royalty to Doty if the
Douglass lamp should be found superior or equal to his.*
In this connection I quote, from a parliamentary paper Extracts from
in my possession, the following extracts from a report made ifessrsrepsteve°n-
in 1870, before the adoption of mineral-oil in British light- so
houses, by the Messrs. Stevenson, engineers of Scottish
lights :
»'lst. The paraffine-flame produced by the four-wick me- Flame pro
chanical lamp is 2^ inches in height, and of great purity fi£e?d by par
and intensity.
" 2d. There is no difficulty, or even trouble, in maintain- carenecessary
ing the flame.
" 3d. According to those in charge, the light is, on the
whole, more easily attended to than that from colza-oil.
a 4th. The same wicks have been used throughout the wicks,
whole thirty days7 experiments, and are still quite fit for use.
* The Board of Trade have since given its authority for the substitu-
tion of mineral-oil in all of the Scottish light-houses.
182 EUROPEAN LIGHT-HOUSE SYSTEMS.
Lamp-glass. " 5th. The lamp-glass used for the experiments has stood
during the month without breakage.
ventilation. " 6th. The ordinary ventilation of the light-room has been
found quite sufficient.
Absence from " 7th. No inconvenience has occurred from smoking of
the wick or smell of the paraffine,
intem- u 8th. No undue rise of temperature of the light-room or
perature of the , ,
loom. apparatus has occurred.
Temperature of u 9th. The temperature of the paraffine in the cistern of
lamp did not, after twelve hours' burning, rise above from
about 55° to 63°.
Fiashing-point. " 10th. The safe vaporizing temperature, or that to which
Young's paraffine may be heated without giving inflammable
vapor, as tested by us with Mr. Kowat's patent instrument,
is about 140°.
Quantity con- u llth. The quantity of paraffine consumed in the first-
sumed. order light was at the rate of 718 gallons per annum. The
consumption of colza-oil is about 800 gallons per annum.
****** *
Cost " Taking the cost of colza-oil at 34s. per cwt., (2s. 9d. 'a
gallon, 68| cents,) which was the price in 1869, adopted in
our recent reports on illumination by gas, and paraffine at
its present price of Is. 4d. (33 J cents) per gallon, we find
that the cost of maintaining a first-class light with colza
and paraffiue will be £110 ($550) and £47 17s. 4d, ($239.33 J)
respectively, thus giving a yearly saving on each first-class
light of £62 2s. Sd., ($310.66§ ;) but if we take the present
contract rate of colza of 38s. M. per cwt., (3s. Id; per gal-
lon, 77 cents,) the saving would amount to £75 9s. 4$.,
($377.33J.) On the supposition of paraffiue being used for
all the lights under the charge of the commissioners, the
Annual saving. saving, calculated on the same basis, would amount to about
£2,874 ($14,370) per annum, but at the present contract
rate of colza the saving would amount to £3,478 15s. Id.
($17,393.89£) per annum.
* * - * * * * *
"We have perfect confidence in recommending the use of
paraffine for light-house illumination. Its introduction
would require to be clone gradually; the light-keepers
would require to receive some instructions in its use, and a
slight alteration would in each case require to be made on
the level of the burner with reference to the optical axis of
the apparatus, and the marks for testing the adjustment of
the lamp to be carefully altered. A full set of directions
would also require to be drawn up and furnished to all the
stations when the change is made."
EUROPEAN LIGHT-HOUSE SYSTEMS. 183
Ko more convincing proof of the utility of permanence Good results of
permanence in
in the peculiar service of light-bouse administration can be fight-bouse sen-
given than the excellent reputation the Scottish lights bearic(
throughout the world for economy and efficiency, and it is
well known that the Commissioners are eager to adopt any
improvement which tends to the increase of either. Mir.
Cunningham has for many years most ably filled the posi-
tion of secretary, and for nearly a hundred years the Ste-
venson family has supplied engineers.
The time at my disposal was too limited to allow me to
visit any of the Scottish light-houses, and I especially re-
gretted that I could not accept Mr. Stevenson's invitation
to visit Bell-Bock light-house. My thanks are due both to
Mr. Thomas Stevenson and Mr. Cunningham for their polite
attentions while I was at Edinburgh.
THE MANUFACTORY OF DIOPTRIC APPARATUS FOR LIGHT-
HOUSES OF CHANCE BROTHERS AND COMPANY, NEAR
BIRMINGHAM.
On my return to London from Edinburgh I visited the
extensive glass-works of Chance Brothers & Company at
Spon Lane, near Birmingham, in compliance with an invi-
tation which I received from Mr. J. T. Chance soon after
arriving in England. This establishment is most extensive,
and is mainly devoted to the manufacture of plate-glass,
which is sent from here to all parts of the world.
A part of the works is, however, devoted exclusively to
the manufacture of apparatus for light-houses, a manufac-
ture commenced by this firm in 1855, in competition with
the lens-makers of Paris, who until that date monopolized
this branch of industry.
Mr. Chance stated that in establishing this part of their
trade they had lost more than $100,000, but that their rep-
utation is now established, and they supply not only Great
Britain, but many other countries, with lenses, lanterns,
lamps, and accessories of all kinds necessary for the service
of lights.
They have in use a great variety of machines for grinding Machines for
, .. , . ^, . polishing prisms.
and polishing the prisms, and the establishment appears to
be as complete in every particular as any which 1 saw at
Paris.
The scientific branch of this industry is in charge of Dr.
Dr. Hopkinson, who is responsible not only for the cor-
rectness of the forms of the various parts of every optical
apparatus, but for their correct assembling, and he person-
ally tests each lens before it leaves the manufactory-.
184 EUROPEAN LIGHT-HOUSE SYSTEMS.
Flashing-lens Among other works in hand, I saw a revolving lens of the
first order for the light-bouse at Start Point, on the coast of
Devonshire, remarkable for having flash-panels that cover
arcs of 60°, which is larger than any before attempted, as
far as I am informed. Heretofore the arcs of first- order
lenses have not extended 45°, and as the amount of light in
the flashes is nearly in proportion to the size of the panels,
it follows that the power of this lens, when compared with
those of similar character heretofore made, is nearly as
3 to 2.
Eed cut to be A red cut showing the position of outlying rocks near
Start Point, will be produced, as is done at the electric lights
at Souter Point, by collecting a portion of the rear light and
throwing it down a tube to a lower light-room upon a set of
totally reflecting prisms, which in turn bends the beam and
turns it out upon the sea.
Apparatus for A new first-order dioptric apparatus for Longships light-
hoShips light' house, on the coast of Cornwall, was also in progress, and I
had the pleasure of witnessing Dr. Hopkiuson's final test
of the accuracy of this lens.
^octor a^so kindly presented me with a photometer,
Dr HO M
sou's photometer, of his own invention, for comparison of lights at a distance,
which is designed to be free from the defects inherent in
those depending on absorption.
It is very compact, and consists of two Nicol prisms,
which can be moved relatively to each other in azimuth. A
little tube carries both the analyzing prism and a second tube
containing the polarizing prism. The latter being turned
till the light, which is viewed through the axis of both
prisms, is eclipsed, the angle through which the polarizer is
moved, is read. The other light being then observed in the
same way, a comparison of the angles gives the relation of
the powers of the lights.
For many years the place now occupied by Dr. Hopkin-
son was filled by Mr. J. T. Chance himself, and to him the
service of light-house illumination is indebted for several
treatises on the subject.
THE LIGHT-HOUSES OF FBANCE.
THE COMMISSION DES PHARES.
I arrived at Paris on Saturday, the 5th of July, and on
the 7th I went to the offices of the Commission des Pliares, or
Light-House Board of France, situated on the hill Trocadero,
which overlooks the Seine and the Champ de Mars. This
nfuse Boardisllt' Board is composed as follows : Four engineers, two naval
EUROPEAN LIGHT-HOUSE SYSTEMS. 185
officers, one member of the institute, one inspector- general
of marine engineers, one hydrographic engineer.
Tbe executive officers of the establishment at Paris are
M. Leonce Reynaud, Inspector-General of the Corps of En- "
giueers des Fonts et Chaussees, who is Director of the French
light-house administration, and M. Allard, engineer of the
same corps, and Eugineer-m-Chief and Secretary to the
Commission.
The entire administration on the seaboard is in the nandsm^i|JJa1^ead-
of the engineers, who, in addition to other duties, are
charged with the work of river and harbor improvements.
At the time of my visit to the Depot des Phares, M. Rey-
naud, who is, I believe, much occupied with other duties,
especially at the Ecole des Ponts et Chausxees, wras absent,
but I had the pleasure of meeting M. Allard, upon whom
the major part of the executive duties devolves.
During my long interview with M. Allard, he kindly
showed me the different parts of the establishment at Tro-
cadero, all of much interest, particularly the grand hall or
council-chamber of the Commission, the museum, the experi-
mental rooms, and store-rooms.
The buildings are placed around a rectangular court-yard i> 6 p 6 1 des
in which are models of light-houses, buoys, &c.
The principal building, which contains the offices of the
commission, is a handsome, structure 150 feet long and two
stories in height, built of brick and limestone in alternate
courses. It is surmounted by a towTer and a first-order Ian- Tower for exi
tern, where experiments are made, and from which a mag- Periments-
neto-electric light is exhibited on occasions of public dis-
play ; as, lor example, the fete nocturne in the Champ de
Mars, ill honor of the Shah of Persia. This fete M. Allard
was kind enough to invite me to witness from the Depot
des Phares, which afforded a most desirable site from which
to view the magnificent spectacle.
The grand entrance hall also contains many models, and
those of the rock light houses of France at once arrest the
attention of the visitor.
The council-chamber of the commission is richly decorated, council cham-
and upon its walls are painted two large charts, each occu-ber'
pying an entire side, one of the world, on Mercator's projec-
tion, showing all the lights now in existence, thus, as M.
Allard happily observed, marking the progress of civiliza-
tion in a most striking manner. The other chart was one
of France, showing not only its lights, but the illuminated
areas.
186 EUROPEAN LIGHT-HOUSE SYSTEMS.
A bust of Augustin Fresnei, engineer of Fonts et Chans-
sees, the first Secretary of the Commission, and the invent-
or of the system of lights which now illuminates the coasts
of most countries of the globe, occupies a prominent
place, not only here, but, as I found afterward, at all French
light-stations, similar ones being placed over the entrance-
Museum, doors at each station I visited. The museum contains all
kinds of illuminating apparatus, both dioptric and catop-
tric, though the latter is not now used in any French light-
house.
The collection of dioptric apparatus embraced many arti-
cles of historical interest, among which I was shown the
first lens made from the designs of Augustin Fresnei, which
was placed in the Tour de Oordouan, and various apparatus
showing the successive steps by which he arrived at the
lens which is now used in all parts of the world.
Haii. The hall also contains models of buoys and beacons.
French bell-buoys have four hammers or clappers, and at
the top of the frame are placed small mirrors to catch the
eye of the mariner.
System of coi- A uniform system is used for the coloring of all the buoys
oririg buoys. and beacons of the coast of France. All of those marks
which should be left by the navigator on the starboard hand
when approaching from seaward are painted red $* those
which should be kept on the port side are painted black ;
those which may be left indifferently on either side are paint-
ed with horizontal stripes, alternately red and black.
Beacons. Beacons are colored in this way only above high-water
mark ; below that level they are painted white.
The red and black are varied as circumstances may require
by painting in white, design of checks, vertical bands, &c.
color of buoys Buoys marking anchors, &c., are painted white. On each
marking anchors. , .. . ._ ., . , . .. ,
buoy or beacon is painted either the entire or abridged name
of the bank or rock that it marks, and buoys and beacons
belonging to the same passage are numbered serially, com-
btu>y™bcnng of mencing to the seaward. The even .numbers are given to
buoys and beacons which the navigator leaves on the star-
board hand, that is, to the red ones, and the odd numbers
are given to the black buoys and beacons. The buoys and
beacons painted with red and black stripes bear names, but
no numbers.
* The red is soon tarnished by the sea-water, and in order to prevent
any error it has been decided that those marks which are painted red
shall hereafter have a white crown a little below their summit.
EUROPEAN LIGHT-HOUSE SYSTEMS. 187
Small heads of rocks in frequented passes may be painted
the same as the beacons, except that only the most promi-
nent part is colored when they show a surface larger than
is necessary for clear distinction.
No oils are kept at the depot, nor are they tested there, as oils sent di-
rectly to the
they are sent by the contractors directly to the light-houses light-houses.
and there thoroughly tested by the engineer of the district.
Lenses and lamps, however, undergo a thorough trial at the len869
depot. The photometer used is different from Buusen's, photometers
used by us, and instead of the standard light and the one
under test being both fixed in position, the former or unit
is moved until the beams, passing through a slit or opening
in the photometer and falling upon a pane of glass which
has a ground surface or is covered with a sheet of paper,
are, when viewed on the reverse side, equal in intensitj*.
The distances from the photometer are then measured by a
tape-line, and reference to a calculated table shows at once
the intensity of the light under test in terms of the standard
or unit. This unit in France, both in the practice of the
officers of the light-house administration and that of the
lens-manufacturers, is always the Carcel burner, consuming
40 grams (G1.728 grains) of colza-oil per hour.
The relation between the French and English unit is not Relation ot
accurately known. I have been informed by Mr. Douglass French Vmts'o'f
1 hat the French unit is estimated by the French and English
gas-engineers as equal to 9.6 candles.
M. Lepaute informed me, however, that it has heretofore
been considered equal to 11 J caudles. M. Lepaute has re-
cently been desired by the French government to ascertain
the exact relative value. M. Allard stated that the French
engineers prefer the Carcel to the candle unit used in
England and the United States on account of greater vari-
ability in power to which the latter is subject in consequence
of irregularities in the wick.
I found this photometer to be easily operated, and the
bringing into contact upon ^Jie pane, the two images of
the slit, seemed to me to show with more precision when the
desired equality of intensities of beams were arrived at than
Bunsen's apparatus.
M. Allard showed me the mode adopted by the Commis-
sion for testing mineral-oil in apparatus especially designed
for the purpose, and shown in Figs. 22 and 23.
A box containing these instruments is supplied to every
light where mineral-oil is used. The qualities to be tested
are the specific gravity and the flashing-point. The specific
gravity is tested by an areometer, (see Fig. 22.)
188
EUROPEAN LIGHT-HOUSE SYSTEMS.
Test for spe- The test-glass is filled with the oil to be tested to within
three-quarters of an inch of the edge ; then the areometer
is plunged in and the specific gravity is read from it. The
standard required is between .810 and .820 at 15° centigrade,
(59° Fahrenheit.) This temperature is obtained in winter
by heating the oil in a water-bath, and in summer by cooling
the vessel containing it by means of fresh water. If these
methods are not available the specific gravity and tempera-
ture of the oil are taken, and a correction of .00074 is added
for every degree below 15° centigrade, or deducted for every
degree above.
Fig. 22.
Fig. 23.
Areometer.
Apparatus for testing the flashing-point.
To test the flashing-point the instrument shown in Fig.
23 is used. The oil to be te^ed is poured into a little cop-
per capsule placed in a water-bath heated by a spirit-lamp 5
a thermometer so suspended as to dip into the oil gives the
temperature. While heating, matches are applied at short
intervals near the surface of the liquid. The degree of the
thermometer at which ignition takes place is the flashing-
point. It is considered that an oil is unsafe for illuminating
purposes if it gives out inflammable vapors below 50° centi-
grade, (122° Fahrenheit,) and the contracts require that the
oil actually used shall not have a flashing-point lower than
600 centigrade, (140° Fahrenheit.)
EUROPEAN LIGHT-HOUSE SYSTEMS. 189
The principal keepers of the lights are required to test oils tested by
the oil when delivered by the contractors. They heat it in thekecPers-
the capsule until the thermometer shows more than 60°
centigrade, then extinguish the lamp, and while the mer-
cury slowly descends apply the match.
Before the introduction of mineral-oil the colza oil for- coiza-oii testa
merly used was required to be of the first quality, perfectly
purified and clarified. The oils delivered by the contractor
were first tested by drawing a certain quantity from each
cask and burning it in two or three night-lamps with floats.
The oil was refused if the lamps, properly arranged, went
out ot themselves before burning twelve hours. If they did
not burn twenty hours the oil was considered, if not bad,
at least of doubtful quality. In this case, or any other where
there was doubt, the decisive test was to compare the oil co^c^1ivetestot
with colza known to be of the first quality. The oil to be
tested was not considered acceptable if, during combustion of
sixteen hours, it did not give as good a flame, or if it depos-
ited more carbon on the wick than did the standard oil, other
circumstances being equal. -In this comparative test either
ordinary constant-level lamps or the regular light-house
lamps were used.
In regard to lamps, M. Allard stated that the French pre- Lamps pre-
fer the mechanical lamp, although the " moderator77 is used
in some of the light-houses, and the constant-level lamp in
others, but in no case is any part of the lamp allowed to
obstruct any portion of the light when the entire horizon is
required to be illuminated. For small orders (below the
fourth) lamps in which the oil is drawn up by the capillary
attraction of the wick are used in most cases.
The French are experimenting with a six-wick burner,
but in M. Allard's opinion the heat generated would be
found to be too intense for the safety of chimneys. As 1
have stated, the English are using the six-wick burner in the
Douglass "lamp of single and double power" for the pur-
pose of producing a powerful flame in thick whether, but, as
far as I am informed, the French have not manufactured any
lamps with more than five wicks.
M. Allard confirmed Mr. Douglass's opinion concerning Caro to be ex.
the great care which should be exercised in regard to t
wicks used in light-house lamps, and stated that in the
French service very great precaution is adopted in procur-
ing and inspecting them.
After my visit to the Depot des Phares I visited the light-
houses at the mouth of the Seine, and on my return to Paris
I found the following note from M. Eeynaud:
190 EUROPEAN LIGHT-HOUSE SYSTEMS.
"COMMISSION DES PHAK.ES,
" Paris, July 19, 1873.
"M. Eeynaud much regrets not having been at the Depot
des Phares when Major Elliot did him the honor to call.
" It1 Major Elliot wishes to see M. Eeynaud on business, he
will find him at the Depot des Phares, Avenue de VjEmpereur,
corner of la place Trocadero, to-morrow, Wednesday, from
2 to 4 o'clock. His approaching departure obliges M.
Eeynaud to indicate an hour instead of asking Major Elliot
to name one that would be convenient for him. He hopes
to be excused, and presents Major Elliot his best compli-
ments.
" L. EEYNAUD."
On my arrival at the depot at the time appointed, M. Eey-
naud received me with cordiality and expressed his desire
to assist me in the object of my mission by any means in
his power.
Question of ii- Our conversation turned mostly upon the subjects of illu-
iampsantl dminants and burners for light-houses, they being the ques-
tions now of greatest interest to the light-house engineers
of Europe, and I found the French fully as much interested
in this subject as are the English.
order of French ^' Rvynaud stated that the Commission des Phares had re-
fubstitSt^miner0 cew% given an order for the substitution of mineral for colza
ai for colza oil. On {n au Of fjie French light-houses, and their lamps were being
changed for this purpose as fast as possible ; that no difficulty
whatever is found in its use ; that it is perfectly safe when in-
spected, and received after proper tests ; and that, while the
consumption by the larger orders of lamps is about the same, it
is, for the smaller orders, very much less than the consumption of
colza,* while its cost per gallon is about one half, and the light
produced is superior and the lamp more easily managed, a change
of wicks being required only at long intervals, the full power
without trimming being kept up from sunset to sunrise.
Burner in use. The burner, or bee as it is called by the French, now in
use, is denominated the bee de V Administration. It combines
the peculiarities of the Doty and tbe'Fresnel burners, with
modifications made by the Commission, especially in regard to
the overflow. By an ingeniously devised screw the overflow
is regulated to suit the temperatures of different climates,
which is highly important.
* It will be found by reference to my account of the improvements in
lamp-burners made by Mr. Douglass, engineer of Trinity House, that in
consumption and illuminating power, colza has been brought to an equality
with mineral oil.
EUROPEAN LIGHT-HOUSE SYSTEMS. 191
In regard to the claims of Captain Doty, which have Question of
, . , ,. , claim of Captain
caused much controversy in England, M. Keyuaud said that Doty as inventor.
Captain Doty presented his burner without conditions to the
French government, and it had paid him a certain amount,
(not stated to me,) not as payment for an invention, but
rather as a reward for calling attention to the economy and
other advantages of mineral oil for use in light-houses, and
pressing its claims for adoption over the vegetable and
animal oils. I afterward ascertained that the French gov- indemnity paid
Captain Doty by
ernment paid to Captain Doty an indemnity of 10,000 francs, noh gov"
($2.000,) and purchased his burners at 44 francs ($8.80) each,
being an excess of 19 francs ($3.80) over the cost of the
burners formerly used.
In this connection the following recent letter from the
Minister of Public Works of France to the British Embassa-
dor in Paris will be found of interest :
" VERSAILLES, August 12, 1873.
" M. L'AMBASSADEUR :
" In acknowledging the reception on the 16th of June
last of various documents relative to the illumination of
light-houses with mineral-oil, your Excellency has done me
the honor to express to me in the name of the Board of Trade
the desire of learning whether, since the publication of the
note of M. Keynaud, Director of the Light-house Service,
he had not arrived at some new facts in support of the obser-
vations it contained on the respective merits of, the Doty
and Fresuel lamps.
" Your Excellency adds that the Board of Trade would
equally appreciate the reception from M. Eeynaud of the
fullest information relative to the merits and price of the
Fresnel lamp manufactured by M. Henry Lepaute.
ki The Minister of Public Works calls to mind that the
note of the Director of the Light-house Service indicates that
two kinds of burners were in use, giving the same results,
viz, the Doty burner and the modified Fresnel burner. Now,
it appears from recent information furnished by M. Eeynaud
that, in consequence of divers changes in details which the
experiments made at the Depot des Phares had induced the
engineers to adopt in each of the systems, it may now be
considered that the two kinds of burners differ but little
more than in name. The light-house service includes
them in the same designation of mineral-oil burners.
u These burners consume the same quantity of oil, have
the same luminous intensity, and offer the same guarantee
of regular action.
192 EUROPEAN LIGHT-HOUSE SYSTEMS.
" Their cost is the same to the French government, viz :
" Burners with 5 wicks, 60 iraucs.
u Burners with 4 wicks, 50 francs.
" Burners with 3 wicks, 40 francs.
" Burners with 2 wicks, 32 francs.
# * # * * # *
" Accept, &c.,
« BEOGLIE.
" His Excellency LORD LYONS, G. C. B."
scotch mineral- The mineral-oil used in the French service is the Scotch,
which is found to be safe and quite uniform in character;
and so anxious have the Scotch manufacturers been to sup-
ply the French lights, and thus gain a reputation for their
oil, that they not only furnish a better article but at cheaper
rates than the French refiners.
Lens-manufac- In regard to the three lens-makers of Paris, M. Eeynaud
stated that all were good and conscientious firms, and the
Commission des Phares made no distinction between them
in giving 4ts orders for optical apparatus.
Designs fur- Designs are furnished by the Commission, and a scale of
nished by Com-
mi ssi on des prices is established by it : these established prices are lib-
Phares. ... .
eral, the commission having in view the object of procuring
good material and workmanship.
Competition in M. Eeynaud thought that competition in regard to prices
price likely to ,-,..,
result iu inferior would induce a reduction in regard to quality, which could
ratus/ c >a not be thought of when the desire is to utilize for the bene-
fit of mariners every ray of light with the least possible
loss of the power with which it issues from the flame of the
light-house lamp.
As before stated, all lenses made for the Commission are
thoroughly tested at the Depot des Phares before being sent
to the district engineers for placing in the light-houses, and
to the interest felt by the government of France in lens-
manufacture, first commenced, after the invention of Fres-
nel, in the city of Paris, is due the kind offer made to me by
nMde?o°fest Jens" "^' ^eynandj to apply the photometric and other tests to any
es ordered by lenses which might thereafter be ordered from Paris by the
United States.
American Government.
Lenses for eiec- Eeferring to the electric lights, of which France has four,
M. Eeynaud remarked that the smaller lenses are better
than the larger ones, and that diagonal bars should be used
for the panels ; as for the lantern, the glass can readily be
cast in one piece and the use of sash-bars thusavoided, which
is highly desirable for these lights.
f°r ^u sPea^n& of the construction of lanterns for oil-lights,
he gave as his opinion that vertical sash-bars do not mate-
EUROPEAN LIGHT-HOUSE SYSTEMS. 193
rially interfere with the beam, thus differing from the well-
known opinions and practice of the English and Scotch
engineers.
M. Keynaud called my attention to his Memoire sur
V Eclair age des Cotes de France as containing much informa-
tion on the subject of the administration of the French
light-house service ; also to his paper on the Application de
VHuile Hinerale a VlUclairage des Phares, (1873,) a translation
of which will be found below. 1 am much indebted to M.
Eeynaud and to M. Allard for the facilities afforded me for
gaining information while at the Depot des Phares, and the
former was good enough to say that he would be glad at all
times to furnish the Light-House Board of the United States
with any information concerning the improvement of French
lights, or on any other points that might be desired, and ex-
pressed a hope that our Board would keep the French Board
advised of its progress in the science of light-house illumi-
nation.
[Translation.]
APPLICATION OF MINERAL-OIL TO LIGHT-HOUSE ILLUMI-
NATION.
BY M. LEONCE REYNAUD,
Inspector- General of Engineers (des Fonts et Chausse'es) and Director of the
French Light-house Service.
The question whether mineral-oil can be practically used
for light-house illumination has been studied for several
years and finally answered. A Ministerial decision of March
29, 1873, made in conformity to a recommendation of the order of the
Light- House Commission, ordered that the new combustible menT forguse'oi
be substituted for colza-oil in all the lights of the coast, mineral-oi
except the floating-lights, for which experiments have not
yet shown it satisfactory.
The object of this article is to show how this measure
came to be adopted, and to examine its merits, both in re-
spect to maritime interests and to economy.
In 1856 the engineers of the central light-house service Experiments
commenced a series of experiments with oil extracted from witb 80hist-°il8-
bituminous schists of the Department of Allier, and soon
saw that the Maris lamp (so called after the name of its superiority of
constructor) was better than all others then in use, theto?s£srt8oiiam
flame being more intense and requiring less attention. This
lamp, still in use, has a single cylindrical wick. A metallic
disk throws the interior air current on the flame ; below the
burner is a rather large cistern, into which the wick de-
S. EX. 54 - 13.
194 EUROPEAN LIGHT-HOUSE SYSTEMS.
scends, and the oil rises by capillary attraction, without the
aid of any mechanism whatever. The flame is more ex-
tended than in colza-oil lamps, being broader and shorter,
but with lens-apparatus this is an advantage rather than
otherwise, especially when the catadioptric rings have been
Eeflector-appa- calculated to correspond. In reflector-apparatus, however,
rat us require con' x
stuut-ievei lamp, this lamp cannot be used, on account of the position and
size of the cistern, this apparatus admitting only the use
of constant-level lamps, the level a few centimeters below
the crown of the burner.
intensity of The intensity of small lens-apparatus lighted by a Maris
tagminerS-oiL "laflIP burning mineral-oil, is nearly double that obtained
with an equal consumption of colza-oil, arid as the former
is much cheaper, it was evidently best to continue the trials,
and, if prudent, to adopt it.
Mineral-oil first Iu 1857 and 1858 mineral-oil was used for a few harbor-
lights. Mariners were well satisfied with them, and the
keepers themselves, who at first had shown some hesita-
tion, came to acknowledge that the flames kept better than
formerly, without requiring as much attention. But some
Accidents.' accidents occurred, which, although not of a nature to
cause an abandonment of the new system, showed that
great caution was necessary ; an ill-regulated flame smoked
so badly that the light was extinguished shortly after light-
ing; a cistern exploded; at another place the chimney and
the upper rings of the apparatus were broken.
continuation of Experiments were then continued at the light-house
experiments. depot, both with the different mineral-oils, and in regard to
the measures to be taken for the desired security. At the
same time the use was extended on our coasts, and soon
every serious reason for hesitation disappeared, at least as
far as regarded its use in single-wick lamps. At the end of
1864 the new combustible was used in forty-one harbor-
lights, and the following year it was ordered to be exclu-
sively used in all fourth-order apparatus, i. e., in all single-
wick lamps.
But the numerous attempts made by engineers and man-
ufacturers to use mineral-oil in lamps of the superior orders,
(which have, as is well known, several concentric wicks)
did not succeed ; the combustion was incomplete, brilliancy
feeble, smoke sometimes abundant.
Doty lamp- While we were still experimenting, Captain Doty, an
burner. American, succeeded in solving the problem which, until
then, had baffled all. In 1868 Mr. Doty brought forward a
lamp for burning mineral-oil, having four concentric wicks,
which was tested according to the method adopted at the
EUROPEAN LIGHT-HOUSE SYSTEMS. 195
light-house depot. This lamp, unlike the one with a single
wick, did not give greater intensity than that obtained
from lamps of the same order consuming colza-oil; but the
consumption was less, and the combustible being cheaper,
a considerable saving to the treasury would result from its
use. Besides, navigation would gain somewhat, for al-
though the intensity immediately after lighting was the
same as that of the old lamps, it was kept up longer, and
did not decrease as much toward morning.
On recommendation of the Light-house Commission, it
was decided that a practical trial of this system should be
made. The mouth of the Canche is marked by two first- ^fi^g "jf^g-
order fixed lights, placed on a line parallel with the shore, Jo uses at m<mth
about 820 feet apart ; one of them was lighted with mineral-
oil from December 12, 1868, to January 26, 1869. The sub-
sequent investigation fully corroborated the conclusions
derived from the Paris experiments. The two lights were
apparently of the same intensity when first lighted; the
consumption of the mineral-oil was about 17 per cent, less
than that of colza ; its flame was easier to manage and kept
better. At first the odor was somewhat offensive to the
keepers, but they became accustomed to it and did not feel
the least inconvenience.
Meanwhile Captain Doty had some two and three wick increase of iu-
lamps made, which, without increasing the luminous inten- teh r^e
sity in as great a proportion as the single- wick lamps, lamp8'
showed themselves superior in this respect to similar ones
burning colza-oil. These results were encouraging, but the
fear of explosion still remained, and caused all the more
uneasiness as a report kindly furnished by the Chairman of
the Light-house Board of the United States of America, who
had been consulted on this subject, stated that in that
country, where mineral-oil is abundant, it had not been
thought advisable to use it in light-houses on account of its
inflammability, the dangers of which were but too well at-
tested by numerous accidents.
But a new kind of mineral-oil, extracted from bog-head* scotch paraffi
and called Scotch paraffine, had been successfully used
at the light-house depot, was found to be much less
inflammable than the schist-oil used till then, and was
used in one of the light-houses of the Canche. Conse-
quently the engineers saw that, before proceeding farther,
it would be necessary to test the comparative merits of the
different oils in market, excluding, however, American pe-
troleum, the composition and properties of which are too
* Local name for eannel coal. — G. H. E.
196
EUROPEAN LIGHT-HOUSE SYSTEMS.
Table of com-
parative values
of oils.
variable. They ascertained the qualities as to luminous in-
tensity and consumption, and Chief-Engineer Maugon had
the kindness to undertake to determine, with his usual ac-
curacy, the flashing-points and other properties useful to
know.
The following table gives the figures obtained :
Table of comparative values of oils.
2|
'o
o
Iti
•53,3
&&*.
^
ci
§|^
'S3 o q
p o a
||
j
%
«§»
Designation of oils.
.2
||a
.2
|
ii
P
1
§£•§
'fL-^
gj
$
2 §*
8
g-c'o
S'c
q
fc£
u
'« M
o
0
III
§
1
p
1
«
^
o
w
M
£
6^
Carcel
Amt. in
Fahr.
Fahr.
units.
grams.
o
o
Achaume at Autun
1
1.56
25.7
77.0
284.0
0. 827
0. 084
J. Barse, Mineral Illumination Com-
pany of Allier, at Buxiere la Grue . .
Graillot Brothers, at Autun . ,
2
3
1.82
1.63
21.9
24.6
78.8
84.2
287.6
300.2
0.818
0. 819
0.087
0.087
Rondeleux, mines of Condamine, at
Buxiere la Grue
4
1.59
25.2
84.2
305.6
0.833
0.093
Hubinet of Soubise, at Autun
5
1.47
27.2
98.6
312.8
0.830
0.099
E. Goutier et Cie, at Autun
6
1.78
22.4
105. 8
320. 0
0.825
0.080
Civil Mining Company of L'Autunois .
Anonymous Company of the Oils of
Colombes .. .
7
8
1.55
1.60
25.8
25.1
107.6
114.8
327.2
334. 4
0.831
0.834
0.098
0.090
Roche et Cie, of Igonay, Saone et Loire
Young's Paraffine Light and Mineral
9
1.45
27.6
120.2
345. 2
0.834
0, 095
Oil Company, Scotland
10
2.18
18.3
161.6
401.0
0.833
0.094
Superiority of
Scotch parafflne.
*It will be remembered that the unit of light adopted by the Light-house Commis
sion is the Carcel burner, Om.020 (0.79 inch) in diameter, consuming 40 grams of
colza-oil per hour.
The superiority of the Scotch oil was thus very evident
in essential respects, as it proved to be at the same time
less inflammable and of greater illuminating power than the
others, and lessened, if it did not completely obviate, the
chances of accident. Still the Light-house Commission,
wishing to be as prudent as the gravity of the interests con-
fided to its care required, though not more disposed than
in the past to repel imprpvements, confined itself to propos-
ing at its session of June 26, 1869, to apply the new com-
bustible to two- wick lamps of third-order lights, and also to
such three-wick lamps as might be used where the colora-
tion of the light required a greater intensity of the luminous
focus, or where it might be thought best to increase the
diameter of the burner, in order to obtain greater divergence.
It was recommended, moreover, to proceed to new studies
of instruments and receptacles having especially in view
the prevention of accidents.
The contract for furnishing mineral-oil of French origin,
made with the firm of Jules Barse, expired at the end of
the year. It was not renewed, and another was made, to
EUROPEAN LIGHT-HOUSE SYSTEMS.
197
Contract
Scotch oil.
fort
run for three years from January 17 1870, with the company
established in Scotland under the name of " Young's Paraf-
fine Light and Mineral-Oil Company." It was stipulated in
the conditions that the specific gravity should be between
0.81 and 0.82 at 59° Fahrenheit, and that no inflammable
vapors should be produced at a temperature below 140°
Fahrenheit. This is much lower than the 161.6° Fahrenheit
found by M. Mangon; it was adopted so as not to create
too many difficulties for the engineers as well as for the com-
pany, after numerous trials had shown that it might be con-
sidered sufficiently low as a limit and still sufficiently high
to give entire security. The price of the oil had been fixed
at 0.85 francs per kilogram, [about 50 cents per wine-gal-
lon,] delivered at the light-houses, and is the same in the
new contract made with the same company, to date from
the 1st of January lasfc, [1873,] all customs duties aflfecting
the product to be refunded. The memoir on the illumina-
tion and buoyage of the coasts of France, published in 1864,
states that colza-oil, the cost of which varies with the mar-
ket, averages 1.51 francs per kilogram, [about $1 per
wine-gallon,] * delivered at the light-houses. It will be seen
that the difference is great. •
Mineral-oil is used in all third and fourth order lights Minerai-oii m
established since the commencement of 1870, in conformity Souses.
with a recommendation of the Light-house Commission, made
mandatory by a Ministerial decision. We now use it in one
hundred and sixteen light-houses, six of which are of the
third order. There is even one light of the second order,
viz, that of Pilier, which, as a considerable part of the arc
of illumination had to be colored red, has been furnished
with a five- wick lamp, as will be explained hereafter. Thirty-
nine third-order lights yet burn colza-oil, and considering
that the advantages of change are well established, it may
be thought that its progress has been exceedingly slow.
But besides the trouble caused by the misfortunes of the
country, there were several reasons for caution on the part
of the engineers of the central service.
Sensible of their responsibility, they asked themselves Questions of
, expense. &c., re-
whether the new combustible would not show in actual suiting from a
, , , . , -.-^ change of illn-
practice some disadvantages not brought out by the Pans mmants.
experiments, and whether it would retain the valuable quali-
ties which caused it to be preferred to all other oils, and so
recommended by the Commission. Besides, it was admitted
by all, even by the contractors themselves, that special re-
ceptacles were necessary for mineral-oil, and hence there
Taking the specific gravity of colza as 0.914.
198
EUROPEAN LIGHT-HOUSE SYSTEMS.
suits.
would result expenditures, which the smallness of our ap-
propriations would require to be several times recommenced.
NO accidents. None of these reasons for delay now exist. During the
three years that the Scotch paraffine has been used in the
light-house service, not an accident has occurred, not a disad-
satisfactory re- vantage has been found. Mariners, engineers on the coasts,
even the keepers, all show themselves entirely satisfied.
The article produced by the Scotch company has lost none
of its qualities. Finally, experiments made at the light-
house depot for the last two years have shown that the
coiza-oii tanks large colza-oil tanks lined with tin, now used in our light-
stutabie for par- houseg? are equally suitable for holding mineral-oil. It has
even been proved that this oil can be preserved for three
years, at least, in well-secured tin cans, without losing any
of its qualities. In zinc, however, it does not do as well,
although it does not become unsuitable for use.
A fact already mentioned, has again been placed beyond
question, and it is of capital importance : for an equal in-
tensity less mineral than colza oil is consumed, whatever
may be the number of wicks, as will be seen by the follow-
ing table, of which the figures may be considered as the
maxima of both kinds of oil :
Economy.
No. of wicks.
Colza-oil.
Mineral-oil.
Consumption per hour.
Luminous
intensity.
Consumption per hour.
Luminous
intensity.
1
In grams.
CO
175
500
760
In fluid oz.*
2.25
6.55
18.73
28.46
Carcel units.
1.6
5.0
15.0
23.0
In grams.
55
160
360
630
In fluid oz*
2.29
6.65
14.97
26.20
Carcel units.
2.2
6.4
14.0
23.0
2
3 . .
4
* 128 to the wine-gallon.
In looking over this table it may appear anomalous that
while the mineral-oil produces a greater intensity than colza
in one and two wick lamps, and the same in four-wick
lamps, it produces less in three-wick lamps, (fourteen in-
! stead of fifteen burners.) This results from the fact that,
for the sake of uniformity, it was thought best to adopt in
the new lamps, the same diameters for all the wicks of the
same rank, which had not been done in the successive
establishment of the different types of colza-oil lamps.
Wick No. 3, which fixes the diameter of three-wick lamps,
is 2.71 inches in diameter in colza-oil burners, and only
2.55 inches in those for mineral-oil. It may also be re-
marked that the saving of oil is comparatively greater in
Question oflamps of this order, and by somewhat enlarging the wicks
bfeS S wicks™11" both consumption and luminous intensity would be increased.
EUROPEAN LIGHT-HOUSE SYSTEMS. 199
These facts established, it seemed that the proper mo-
ment had come to order the substitution of mineral for colza
oil in all the light-houses: and at the same time the ques-
tion occurred whether it would be advisable to allow (as
had been done before in the case of third-order lights)
lamps with more than the regulation number of wicks to
be used in first and second order light-houses, where greater
intensity appeared desirable.
This measure, as before stated, had already been adopted
in the exceptional case of the Pilier light. As the Light- at°n of
house Commission proposed to color this light red, in a cer-
tain angular space, to warn mariners from the shoal of Les
Boeufs, and did not wish to lessen its range, it was neces-
sary to increase the intensity of the focus; so it was thought
best to use mineral-oil with five instead of three concentric
wicks. This experiment was crowned with entire success.
The engineers of the central service hesitated much
before deciding in favor of a change, and their hesitation
increased when they perceived the consequences of innova-
tion. While inclined to propose an increase in the number
of wicks, they were prevented by a consideration most
powerful with them, the profound respect which they enter-
tain for the memory of their illustrious predecessor. Augus-
tin Fresnel, after many experiments and mature consider-
ation, established the relations, till now observed not only
in France, but by all maritime powers, between the diame-
ters of the burners and the dimensions of the lens-appa-
ratus, and it will be easily understood that imperious
necessity alone would excuse any alteration. It was, how-
ever, soon remembered that there was at the light-house
depot a few years ago a gas-burner originating with An-
gustin Fresnel, which had five concentric rings of small nel-
apertures. Unfortunately this burner is lost. The brother
of the illustrious inventor borrowed it to make an engrav-
ing; it was destroyed by fire, and the engraving (annexed
to FresnePs complete works) does not give the dimensions.
Still the scale on which it is shown is sufficiently large
(0.25) to justify some confidence in measurements taken by
dividers, and thus it was found that the diameter of the
exterior ring must have been about 4.72 inches, while the
same diameter (taken in the middle of the thickness of the
wick) is but 3.34 inches in first-order colza-oil lamps and
4.13 inches in 5 wick mineral -oil lamps. It is to be ob-
served, moreover, that the text (vol. 3, page 514) clearly nosircd in-
i fl ., . .. crease of dura-
shows that the aim of the invention was to increase the tion of flashes m
duration of flashes in eclipse-lights, and that this result eclipse-lishta
200 EUROPEAN LIGHT-HOUSE SYSTEMS.
could be obtained, as regards the burner, only by an increase
in diameter. Thus we have the proof that this was one of
the inventor's efforts to prolong the duration of the lumi-
nous apparitions in eclipse-lights 5 the only objection to the
new lens-apparatus being that it was inferior in this respect
to the old reflectors $ and it is known that in the two first-
Fresuei lamp, order eclipse-lights constructed during the life- time of Fres-
nel (Cordouan and Planier) the luminous rays passing
above the drum are used entirely to prolong the flashes
produced by the principal lenses 5 the inventor thus sacri-
ficing intensity to duration.
It is easily understood why he did not exceed four wicks
and the resulting diameter when the combustible was colza-
oil. A considerable increase of expense would have been
the result, and thus an arm might have been furnished. to
the opponents of the new invention. There was also danger
of meeting with practical difficulties, since there was no
certainty that such vigilance as a four-wick lamp requires
could be obtained from light-keepers ; and, indeed, it was
some years before we could succeed in this respect. ^
Thus it may be inferred that Augustin Fresnel considered
the four-wick burner the highest limit which could be ob-
tained with colza-oil, and that he sought for a new com-
bustible which might allow him to proceed further. It is,
therefore, only carrying out his ideas, to use mineral-oil in
order to increase to a certain extent the dimensions of
burners. It is also to be remarked that the height of the
flame is riot increased, so that multiplying the wicks mostly
affects the horizontal divergence, which is all used for sea-
illumination.
A final question was considered, whether instead of con-
fining the advantages of the measure to a certain number
of lights, it would not be better, although more expensive,
to give each apparatus of the same order the same number
of wicks. As this would be a more regular system, and
give more security to mariners, the Light-house Commission
Proposal to reg- did not hesitate to answer it in the affirmative. They pro-
ulate the number ITT. f •>
of wicks and or- posed to make five orders of lights, establishing for each a
constant proportion, more decided, however, than before,
between the diameter of the burner and that of the lens-
Compar ati ve apparatus. The following comparative table of the old and
table of old and . , n ., , , , , ,
new systems, new systems shows the advantage of the latter, both to
mariners and the public treasury :
EUROPEAN LIGHT- HOUSE SYSTEMS.
201
202
EUROPEAN LIGHT-HOUSE SYSTEMS.
Results pro- The preceding table, which clearly shows that the new
iightJin se" system notably increases the intensity of fixed lights, shows
nothing as to eclipse-lights, for the reason that with the
latter the advantages gained are divided, between increase
of intensity and increase of duration of the luminous appa-
ritions, and the figures showing the effect on each of these
two phenomena vary greatly for each order of lights, ac-
cording to the number of divisions of the lenticular drum,
the rapidity of rotation, and the arrangements for prolong-
• ing the flashes. Therefore, without unnecessary details, we
shall only give the proportional values, constant in each
order, of the increase of intensity and of duration which the
new lamps give to the flashes of eclipse-lights.
Table of increase in eclipse-lights.
Order of light.
Proportional increase.
Intensity.
Duration
of flashes.
First
Per cent.
7
26
76
35
Per cent.
22
22
59
58
Second.
Third ...
Fourth
Fifth *
* There are no fifth-order eclipse-lights on the coasts of France.
Besides, whether the light is fixed or eclipse, the quantity
of light emanating from the apparatus is constant for each
order, and it may be concluded from the above figures that,
as our sea-coast lights now are, the total intensity of the
increase of in- luminous beams sent to the horizon will be increased nearly
tensity by use of
mineral-oil. 45 per cent. This, however, does not take into account the
very considerable advantage resulting from the fact that
flames fed by mineral-oil preserve their brilliancy longer
than the others. The percentage would be much higher if
the comparison, instead of being made when the lights are
in their first condition, were made after they have been
burning for a few hours. The annual saving in oil will
amount to 106,676.80 francs, ($20,268.59,) about 32 per cent.
Recapitulation Thus the advantages of the change are that 45 per cent.
tneatcnangeges ° more light is sent to the horizon, and 32 per cent, 'is saved in
the expense of oil.
There is, however, one objection to the new mode of illu-
mination: it depends on the qualities of a foreign article.
This may be adulterated, its price increased more or less
EUROPEAN LIGHT-HOUSE SYSTEMS. 203
when its merits, better known, cause a greater demand, or
our supplies might be cut off in case of a maritime war, a
sad calamity which we must at the present day certainly
take into account. It is to be observed, however, that the
formation of bog-head is very active, and aside from their
own integrity the Scotch company will be more interested
to maintain the reputation of their article the more their
customers increase; the French manufacturers also will
probably be induced by foreign competition, and perhaps
by governmental regulations, (which would certainly be
justifiable,) to improve the article they manufacture, if not
as to luminous intensity, at least as to safety ; wars, more-
over, have ceased to be of long duration ; finally, the burners
of our mechanical lamps are so arranged that in order to go
back to colza, we have only to close the tube regulating the
level of mineral-oil. All our mechanical lamps will be re-
tained and kept in use ; the burners alone will be altered.
There are at present two kinds of burners in use, both of Kimls of burn
ers in use
which give the same results; the Doty burner, manufac-
tured in Paris by Messrs. Barbier & Fenestre, and another
made by Messrs. Henry-Lepaute, called the modified Fres-
uel burner.
To complete the change now commenced of colza-oil lamps
to mineral-oil lamps, and to purchase the various receptacles
and implements needed, will not require more than 50,000
francs ($9,500) more. This amount will be saved in less
than a year by the new system.
THE LENS-MAKERS OF PARIS.
During my limited sojourn at Paris I visited the manufac-
tories of MM. Henry-Lepaute, MM. Sautter, Leinonnier &
Co., and MM. Barbier & Fenestre. These three firms were,
until the establishment of the works of Chance, Brothers &
Co., in England, the exclusive manufacturers of dioptric
apparatus, and supplied all countries. They all have exten-
sive establishments, and are contractors, not only for lenses,
but for light-houses, (particularly small ones of iron,) for dif-
ferent European countries.
The method of grinding and polishing the prisms and
lenses is almost identical at the different establishments,
all of which keep on hand a large stock of prisms, adapted
to different sizes of apparatus, so that orders can be filled
by them with but little delay. Lenses, lamps, and lanterns
were in different stages of manufacture under orders from
different countries.
204 EUROPEAN LIGHT-HOUSE SYSTEMS.
Establishment At M. Lepaute's, in the faubourg Saint Germain, I was
plute. Henry"Le' shown among others a beautiful third-order lens, a dupli-
cate of which I afterward saw at the Industrial Exhibition
at Vienna.
Lens shown. It was for a " fixed light varied by flashes, " 180° being
provided with fixed-light apparatus, and the other half
divided into eight flash-pauels ; the characteristic of the
Characteristics, light would therefore be, that between comparatively long
periods of fixed light, there would be observed eight short
consecutive flashes; quite a new characteristic and a most
distinctive one for a light to be placed within short dis-
tances from other varieties of lights.
Swedish light- M. Lepaute showed me his designs of a tower and diop-
tric apparatus for a light-ship the construction of which he
was about to commence for Sweden. This design will be
readily understood by an inspection of Plate XXXI.
Description of I was much interested in modifications of apparatus for
apparatus for
floating lights, floating lights, and am indebted to him for a paper on the
subject, from which the following extracts are translated.
After describing the ordinary catoptric fixed light, he says :
" The arrangement of revolving floating lights is similar to
those of fixed floating lights, but the reflectors are 36 cen-
timeters in diameter, and but eight in number, the same as
the faces of the lantern. The entire system of lamps and
reflectors is supported by a chariot on rollers which has a
wheel toothed on the inner side, to which a rotary move-
ment is given by a pinion which communicates by means of
a stem fixed by collars along the mast, with the clock-work
placed between the decks. A special mechanism has
been added to the floating light at Dunkerque, so that when
the sea is too boisterous it may be hoisted only half-way up
the mast and yet be made to revolve.
Construction of " For several years attempts have been made to construct
floating dioptric ,, . ,. .,., „ •.-,*,• -, i -,
lights. floating dioptric lights. One method which has been em-
ployed, is to suspend on gimbals to an armature sliding along
the mast, three harbor-lights (feux de port) lighting 235°
each with its lantern.
" There has also been used a system of eight or ten small
dioptric apparatus for signal-lights, 15 centimeters in diam-
inventionof M. eter? suspended around a mast in a single lantern. In 1848
Henry -Lepaute, our father projected a system of two fixed catadioptric ap-
paratus, 60 centimeters in diameter, suspended on gimbals
in a single lantern, and each lighted by a two- wick constant-
level lamp. The power of this apparatus is very great, and
its service very simple.
" In 1869 we recommenced our father's studies of an ap-
0
H
i
*
EUROPEAN LIGHT-HOUSE SYSTEMS. 205
paratus for a floating catadioptric light, illuminating the
whole horizon, and lighted by a single two-wick lamp.
Our project was appreciated, and in 1873 we were charged
with the construction for Sweden of an apparatus of this Swedish light-
kind, placed in the center of an open iron frame-work, which 8hlp-
takes the place of the mast of the vessel. (See Plate XXXI.)
" The engineers, both French and foreign, who have ex-
amined this apparatus in course of construction, have
expressed to us their good opinion of the result which can
be obtained by this new arrangement.
" For revolving lights we have proposed to place before Moating re-
I the reflectors, annular lenses of 15 centimeters focal dis- volving ligbts'
| tauce, which will considerably augment the range of such
I an apparatus.
"Plate XXXII shows a floating eclipse-light, which is ri o a 1 1 u g
entirely catadioptric, composed of two annular half-appa- e<
ratus suspended on gimbals at the two opposite extremities
of the same armature, and each lighted by a two-wick
burner. These two apparatus are placed in the same lan-
tern. The objection that the intervals between the flashes
are unequal on account of the distance of the two half-ap-
paratus is of but little importance, as there is not more
| than a half-second difference during a rotation of four
j minutes, which, with three lenses in each half-apparatus,
produces flashes of twelve seconds7 duration.
" We have just finished a study of a floating catadioptric Floating Cata-
light with a single burner placed in a single lantern and ar- dloptn
ranged similarly to the floating catadioptric fixed light.
" By making floating lights with a single burner we have
the advantage of being able to make apparatus of sizes vary-
ing from the sixth order, 30 centimeters interior diameter,
to the three and a half order, 70 centimeters interior diam-
eter.
" The power of these apparatus is much greater than that
of those hitherto used, and the advantage of having but one
lamp makes the service much easier."
M. Lepaute has also on exhibition at his manufactory a Mineral- on
lamp suitable for burning mineral-oil, which was designed lamp of
by M. Lepaute, Sr., in 1845.
The papers in support of his claim to the original inven-
tion of a lamp suitable for burning mineral-oil in light-
houses, as well as the reasons for such claim, are fully set
forth in an interesting paper on the subject of light-house
burners, written at my request by M. Henry-Lepaute fils,
and which he has kindly sent me since my return to Amer-
ica. A translation of it will be found on page 208.
206 EUROPEAN LIGHT-HOUSE SYSTEMS.
Lamp-valves. In the construction of mechanical lamps at this establish-
ment, the valves are made of calf-bladder, and it was stated
that for this use, this material is superior to any other.
E stabiishment Sautter, Lemonnier & Co. have a very extensive establish-
monnier&rco. e ment near the Champ de Mars, and their shops are largely
devoted to the manufacture of metal-work of light-houses.
° f Toe ParaPets Pf light-houses and the floors of the galleries
or " decks," as we call them, are in Europe, ordinarily of
stone. I saw, however, one making for Eussia, of cast iron,
which we have found to be the best material for this pur-
pose, in consequence of the leaks at the joints of stone,
caused by contraction and expansion due to our extremes of
temperature.
M. Sautter, who speaks English with fluency, was attached
to the Eoyal Commission which reported on the condition
of the light-houses of Great Britain in 1861. He has had
laut- mucn experience in the specialty of testing of prisms and
lenses, and I was much interested and instructed in the ac-
count of the means and care which he takes to insure that
every dioptric apparatus supplied from his establishment
shall be of the highest standard of efficiency. It should be
stated in this connection that the other lens-makers also
exercise great care in this particular.
I observed at this establishment a handsome lantern for
an electric light, designed for the Industrial Exhibition at
Vienna, (represented by Fig. 24,) in which the diagonal
sash-bars are reduced to a minimum thickness, viz, one-half
inch.
Besides this lantern there was an iron tower for a harbor*
urn- light, of good design and workmanship. I was shown the
" Farquhar w burner, of which Sautter, Lemonnier & Co. are
the sole proprietors, and which they claim is superior to
all others in that it gives a whiter and higher flame, of
greater intensity, caused by the fact that the tubes for the
supply of air to the concentric flames are of such capacity
as to produce equal currents to the interior and exterior, so
that the draught is the same to all parts. The flame is of dif-
ferent shape, not being pointed like those of ordinary lamps.
o E|tabiishm^t At the establishment of Barbier & Fenestre, I was shown
Fenestre. a second-order lens ordered by us for Cape Elizabeth, a
second-order lens for Scotland, a third-order lantern (of
iron) for Uruguay, to cost 11,500 francs, ($2,300,) and fifth-
order lanterns (of bronze) for Venice and for France, cost-
ing each 3,200 francs, ($640.)
oil-cans. This firm were also making a large number of oil cans or
butts for mineral-oil destined for use in the French service.
REVOLVING CATADIOPTRIC APPARATUS
FOR LIGHT-SHIPS. PLATEXXXII.
EUROPEAN LIGHT-HOUSE SYSTEMS.
Each of these, cans, which are of sheet-iron, contains seven ty-
five liters, (about 20 gallons,) and costs SOfrancs, ($6.) They
are hung in iron stands on pivots placed slightly below the
middle, and the cocks are at the tops of the cans, the advan-
tage claimed being that, as the cocks, except while oil is be-
ing drawn, are always in the air, there is no danger of leak-
age of this subtile fluid.
Fig. 24.
207
Lantern for electric light.
Barbier & Fenestre have purchased from Captain Doty Doty burner,
his patent for mineral-oil burners, (see Fig.2,Plate XXXVI,)
except as regards Great Britain and the United States, where
he reserves the right, and the French government, with
which he has made special arrangement. They state that
they are making mineral-oil lamps for light-houses in all
parts of the world, and that mineral-oil has been adopted in
most countries of Europe, as well as in South America and
Canada. All the lens-manufacturers were busy in fitting the
colza-oil lamps of the French light-houses for the use of min-
eral oil.
A variation of one millimeter (^§- of an inch) in the height
of the overflow in winter and summer is provided for.
The tops of all burners made by French lens-makers are copper tmrn-
of copper. I suggested to one of them that we had found ers>
iron to be much more durable, and he concurred in the opin-
208 EUROPEAN LIGHT-HOUSE SYSTEMS
ion that iron would iiot submit as readily as copper -to the
destructive action of the flame.
Lanterns and lenses are differently constructed for differ-
ent countries, some preferring the diagonal bars, on ac-
count of the less obstruction to the light, and others prefer-
ring the vertical ones, on account of the greater economy.
The difference in cost between the two kinds of lenses was
stated to be for the first order about 1,000 francs, ($200.)
Lenses suited Lenses are made to suit the height above the sea-level at
aboveirethe awL which the different orders are usually placed, and any ex-
cess of such height requires special calculations and adjust-
ments. Unless otherwise stated, the height at which a first-
order lens is to be placed, is supposed by the makers to be
Photometer bet ween 150 and 200 feet above the sea. The photometer
used by all the lens-makers in Paris is the same as I have
described as in use at the Depot des Phares. I was informed
. that most countries use the " mechanical lamp " for the first
.Lamps used, tor
different ordersof and second orders of lights, the " moderator" for third and
hgbts.
fourth orders, and common (capillary attraction) lamps for
the fifth and sixth orders, but that the sixth-order lamp is
little used.
I found the members of the several firms all to be cour-
teous and intelligent gentlemen, and my experience with
them at their offices and manufactories confirmed the high
opinion I had previously entertained, and which were de-
rived from my correspondence with them and from the ex-
cellent quality of the apparatus furnished to us.
1 should state, before concluding my notes in regard to Paris,
that Mr. Washburne, the American Minister, was absent
at the time of rny visit. I am, however, under obligations
to Colonel Hoffman, the secretary of legation, for his valu-
able assistance.
[Translation.]
REMARKS ON BURNERS EMPLOYED FOR LIGHT-HOUSE ILLU-
MINATION.
BY HENRY-LEPAUTE BROTHERS.
In all countries in the world burners with concentric wicks
are used in light-house apparatus, the number of wicks
varying from one to four, according to the order of the lens.
These burners were invented in 1821, on the principle of
burSeVrsnti0wit°hf those of Argand, by MM. Augustin Fresnel and Arago.
concentric wicks, j,^ concentric wicks are separated by air-spaces for supply-
ing the oxygen necessary for good combustion.
EUROPEAN LIGHT-HOUSE SYSTEMS.
209
The conditions fulfilled by the ordinary Fresnel burners
are the following :
Order of lens.
Number
of wicks.
Dimensions of fully devel-
oped flames.
Luminous in-
tensity in
Carcel units.
Maximum di-
ameter.
Height taken
from
the burner.
First
4
3
2
2
1
1
Millimeters.
90
75
45
38
30
27
Millimeters.
100
80
70
65
45
37
23
15
5
3
1.6
1.3
Third
Fourth
Fifth
Sixth
Table of ordin-
ary Fresnel burn-
ers.
I n t e n s ity of
burner of 1845.
Ill examining this table it will be noticed that third-order
apparatus, interior diameter one meter, is lighted by two-
wick burners, differing but little from those employed in
fourth-order apparatus, the interior diameter of whose op-
tical part is but half a meter.
In 1845 M. Henry-Lepaute, Sr., who had been a colaborer Efforts of M.
J Henry - Lepaute,
in the experiments and construction of the apparatus de- sr.,to'mcreasethe
power of burn-
Signed and calculated by M. Augustin Fresnel, sought to ers.
apply to third-order lenses more powerful burners than those
then in use. After his own drawings he then had made, Burner of i845.
by M. Blazy-Jal lifter, a two-wick burner of special construc-
tion. The two wicks, respectively 54 and 28 millimeters in
exterior diameter, were separated by a double air-space,
and an air-tube was placed around the larger wick. These
air-tubes were elongated and enlarged below, and the chim-
ney-holder slipped over the outside. This burner gave an
intensity of from four to five Carcel units, and consumed
200 grams of colza-oil per hour. Some experiments were
made in 1845 in the workshops of M. Heury-Lepaute, Sr.,
and M. Leonor Fresnel, engineer of the corps des ponts et
chaussees and director of the French light-house service,
verified the principal results by one of his assistants. These Adoption of
n. ,1 TL-T i burner of 1845 by
new burners were adopted by the kingdom of the Nether- kingdom of the
lands for the light-houses of Brouwershaven, (1845-1847,)
Scheveningen, (1851,) Renesse, and Schiermonikoog. The
French government, while recognizing the merits of these
burners, did not adopt them, not wishing to alter the standard
burners invented by Messrs. Fresnel and Arago. For this
reason M. Henry-Lepaute continued to make them only
when specially ordered.
In 1868 the question of the use of mineral-oil in light-
houses was brought up. Previous experiments had Bot
given very good results. An American, Mr. Doty, pro-
posed a form of burner which succeeded quite well for
S. Ex. 54 - 14
Question of the
Doty burner.
210
EUROPEAN LIGHT-HOUSE SYSTEMS.
schist-oils, but its arrangement and dimensions differed from
the standard which the light-house administration had not,
E xP eriments up to that time, consented to modify. About that period we
were making numerous experiments relating to the burning
of mineral-oil, and after many attempts we succeeded in
constructing a burner with air- tubes enlarged below, and
with a tube exterior to the large wick. The arrangement
was almost identical with that of the 1845 burner invented
by our father, except that the air-space between the wicks
was not double. We then experimented with the 1845
burner, feeding it with mineral-oil, and found the combus-
tion very satisfactory,
invention of In 1869 we invented the truncated-cone burner, preserv-
bum?r?i869.'c°neing exactly the dimensions of the Fresnel burner for lights
of all orders. Specimens of these burners were sent in 1869
to the light-house administrations of Sweden, Norway,
comparison Denmark, the United States, and Brazil. The French ad-
bvurnerthe )oty ministration tried our truncated-cone burners, comparing
them with the Doty, and found them always equal, and
sometimes superior, especially the one-wick burner. Still
they charged us to try to modify the Fresnel burner so that
with the same general arrangement, it might, by means of
some additions, be used for mineral-oils.
The experiments undertaken in 1872 succeeded, and we
fixed upon the arrangement of the new modified Fresuel
burners of 1873, which are now being substituted for the
ordinary Fresnel burners, so that schist-oil may be used in
all light-houses of France. The success of these burners is
due in a great measure to the addition of an exterior air-
tube, as in the 1845 burner ; an arrangement also used by
Mr. Doty in his burners.
In fine, all schist burners now in use are reproductions
of the burner invented in 1845 by M. Henry-Lepaute, Sr.,
still in actual use in a large number of light-houses in Hol-
land. The conditions fixed by the French administration
for the dimensions and intensity of the new modified Fres-
nel burners are the following :
Table of modified burners.
Modification of
the Fresnel burn-
er, 1872.
Exterior
tube.
Table of modi-
fied burners.
Order of lens.
^
z&
If
&
Dimensions of the fully
developed flame.
Luminous in-
tensity in
Carcel units.
Maximum
diameter.
Height
taken from
the burner.
First
5
4
3
2
1
1
Millimeters.
105
85
65
45
25
25
Millimeters.
110
90
80
70
45
45
30
23
14
6.4
2.2
2.2
Third
Fourth
Fifth.
Sixth
- n
2 x
§5
2
c
-
n co
"o r"
fn
n
r
EUROPEAN LIGHT-HOUSE SYSTEMS.
211
It will be seen that above the fifth order the number of increase i n
, , . i mi • ±1 i ^ - t number of wicks.
wicks has been increased. There is thus obtained a greater
intensity and more horizontal divergence, and as schist is
cheaper than other oil the expense of illumination is not
increased.
The following table clearly shows the differences between
the old and new systems :
Comparative table of the dimensions, consumption, and intensities of the bur-
ners employed in the French light-house service.
Table of differ-
ences.
Order of light.
Number of wicks.
Outer diameter of wicks in
inches.
Consumption
per hour.
1
.22
•3
a
2
i
ci
n
i
d
«
In grams.
In fluid oz.*
ORDINARY COLZA-OIL
BURNERS.
First order
4
a
2
2
1
1
5
4
0.98
1.10
0.94
0.83
1.10
0.94
.18
.18
1.85
1.97
1.73
1.50
2.68
2.91
3.54
760
500
175
110
60
50
900
630
360
160
55
55
28.46
18.73
6.55
4.12
2.25
1.87
37.42
26.20
14.97
6.65
2.29
2.29
23
15
5
3
1.6
1.3
30
23
14
6.4
2.2
2.2
SocAnd order
Third order, (large size)
Fourth order, (third
order small size.)
Fifth order, (fourth
order large size.)
Sixth order, (fourth
order small size.)
MODIFIED FRESXEL BUR-
NER FOR MINERAL-OILS.
First order
1.97
1.97
2.75
2.75
2.75
3.54
3.54
4.33
Second order
Third order
3
2
1
1
.18
.18
.18
.18
1.97
1.97
Fourth order
Fifth order
Sixth order
* 128 fluid ounces to the wine-gallon.
NOTE.— The intensities obtained by burning colza-oil in the modified Fresnel bur-
ners are as nearly as possible the same as those given by mineral-oils.
212 EUROPEAN LIGHT-HOUSE SYSTEMS.
burner Fig. 1 of Plate XXXIII shows the arrangement of the air-
tubes and wicks in the ordinary Fresuel burners. The
ascent and overflow of the oil is also shown.
45paute ri^ ^ Plate XXXVI, shows the arrangement of the two-
wick burner invented in 1845 by M. Henry-Lepaute, Sr. It
will be seen that the air-tubes are longer and enlarged
below; it will also be remarked that the tube between tjie
wicks is double. In all these burners the wicks are lowered
and raised by racks and pinions.
caFyllbm™erConof ^^' ^' Plate XXXIII, shows the arrangement adopted in
iienry-Lepaute, our 1869 burners. All the air-tubes are elongated below,
increasing in diameter. There is, as in the 1845 burner, an
exterior tube, and a disk is placed in the center of the
burner when mineral-oils are burned.
Modified Fres- Fig. 3, Plate XXXIII, shows the form proposed by us and
adopted by the French administration for all French lights.
The air- tubes are arranged as in the ordinary Fresnel
burner. There is also an exterior tube shorter than the
others. The chimney-holder is shorter than in the ordinary
burner, and there is a disk moved by a rack and pinion,
which is necessary when burning mineral-oil. All the new
burners are made of copper.
rSeofib hi°Vurn" In l3urners fed with- mineral-oil the oil should rise to from
35 to 00 millimeters below the crown of the burner, on ac-
count of the volatility of these oils. It is the same when a
constant-level lamp is used. Furthermore, it is necessary
that this level should be raised or lowered in the same
burner, according to the nature of the oil and the surround-
ing temperature.
Two kinds of methods are employed for varying the level
of the oil.
1ST. LEVEL VARIED BY APPLIANCES IN THE INTERIOR OF
THE BURNER.
Level varied by Whether the Henrv-Lepaute, the clock-work, or the mod-
an interior appa- - .. .. ,
erator lamp is used, an excess of oil cannot be entirely sup-
pressed, and there should be a means of varying the level
in the burner itself.
Level varied in ^n the Doty burner, (see Fig. 2, Plate XXXVI,) an ap-
thel)otyburuer- pendage for this purpose is attached to the outside of the
cistern.* This has the disadvantage of being fragile, and
* By the following communication, which I have recently received
from M. Lepaute, it would seem that the French government has decided
to use this appendage :
"A modification has been made in mineral-oil lamp-burners for the-
purpose of regulating the supply of oil. This modification consists of
n
x
- n
2 33
i
r c
- *!
sa
x n
cz
S H
n w
n
EUROPEAN LIGHT-HOUSE SYSTEMS.
obscures the light in one direction. All the systems pro-
posed by us are for the interior of the burner, and have been
used with success since 1869.
In the modified Fresnel burners, (Fig. 1, Plate XXXIV,)
the oil overflows into a central tube, which can be length-
ened by means of short sections (B) screwed on. These are
of determinate lengths, and are fixed in place by a wrench,
(A, Fig. 1.)
When it .is required to burn vegetable or animal oil with
an overflow, the tube is stopped by a cap, (C.) A friction-
stem carries the disk. These various operations cannot be
performed when the burner is lighted, and, besides this
disadvantage, the level of the oil can be varied only by a
considerable amount, which must be determined in ad-
vance. In France, where the temperature is moderate, and
only paraffine is used, these disadvantages are not great, but
they would be serious if the burners were used where the
temperature varied greatly and for all kinds of mineral-oils.
We use two other methods by which the level of the oil
and that of the disk can be varied while the burner is lighted.
In the arrangement shown in Fig. 2, Plate XXXIV, a slide valve sys-
double oil-tight envelope is placed inside the central wick- te
tube, and the tube is pierced with a longitudinal slit through
which the oil flows. This slit is closed by a slide-valve
raised and lowered by a rack and pinion, the stem of which
passes through a packed chamber. When the slide is
raised entirely it closes the slit, and vegetable or animal oil
can then be burned with an overflow. The disk is carried
by a guide-stem placed in the central air-tube and moved
by a rack and pinion.
In the arrangement shown by Fig. 3, Plate XXXIV, the Telescopic-tube
overflow of oil is managed the same as in the modified Fres- 8ys
nel burners except that the overflow-tube is lengthened by
an interior sliding tube worked by means of a rack. The
disk is moved by a rack and pinion passing into the over-
flow tube and through a packed chamber which prevents
the leakage of oil.
an appendage added to these burners, and which constitutes a constant-
level." (It is represented in Fig. 5, Plate XXXV.)
"The two solid caps which accompany each burner are intended to be
used in case it is necessary to have recourse to colza-oil; the cap with
the wire-cloth (toile mtialliquc) is used to cover the three tubes when
mineral-oil is used.
"With burners thus modified the overflow need not be limited to a
few drops, as heretofore required."
This seems to me an excellent arrangement, and not subject to the ob-
jections mentioned by M. Lepaute.— [G. H. E.J
214 EUROPEAN LIGHT-HOUSE SYSTEMS.
2D. LEVEL VARIED BY EXTERIOR MEANS.
These various systems of our invention can be applied to
System for rais- all the orders. The oldest and most simple, Fig. 1, Plate
XXXV, is applicable to apparatus of the sixth, fifth, and
fourth orders, in which the lamp with its cistern is attached
to the interior of the lens. The bottom of the cistern regu-
lates the level of the oil in the burner, and a graduated
scale shows the amount of variation. The valve-stem is
long enough to always raise the valve from the mouth oi'
the cistern. Where the capacity of the lamp is greater, the
cistern is carried by a sliding armature (Fig. 2, Plate XXXV)
moved by a rack fixed to one of the uprights of the appa-
ratus or the lantern, and the level is established in an open
vessel fixed at the height of the focal plane, and is regulated
by the mouth of the neck of the cistern.
In these two systems the cisterns are hermetically closed,
and they must be raised arid inverted to be filled unless
they are furnished with a movable plug at their upper part.
To obviate this inconvenience, which is quite serious when
the lamp is of great capacity, we employ various means.
In tne system shown by Fig. 3, Plate XXXV, the level
pieces. js established in an enlarged part of the conduit in which
loosely enters the end of the oil- tube, on which a screw-
thread is cut. On this an extension-piece slips, the lower-
ing or raising of which varies the level as indicated by a
graduated scale $ a cock above shuts off the oil when the
screw-plug in the upper part of the cistern is opened for
filling.
System with an in the svstem shown by Fig. 4, Plate XXXV, the air-
inclepeudent air-
tube and sliding tube is prolonged to the top of the reservoir, and is
extension-p i e c e
moved by a rack, lengthened at will at the bottom by a sliding t ube moved
by an exterior rack. Another rack moves the valve down
into its socket, and thus shuts off the descent of the oil
when the reservoir is being filled. These last two systems
take but little space, and are very simple and easy to re-
pair. All these systems have been in use in Sweden, Nor-
way, and France for several years.
Recapitulation. To recapitulate, the requirements for burning mineral-oil
are : special burners with powerful currents of air, means
of varying the level of the oil in the burner according to
the surrounding temperature and the nature of the oil, and
means of raising and lowering the central disk, which sends
air into the interior of the central flame.
Smoke-funnels. ^ur experiments have induced us to modify the form of
smoke-funnels (fumivores) and dampers, and to adopt the
EUROPEAN LIGHT-HOUSE SYSTEMS. 215
forms represented by Fig. 4, Plate XXXVI. The glass
chimney is surmounted by a copper continuation of the same
diameter, which sets into the damper. The latter is cylin-
drical, with a spherical part midway of its length, in which
the register moves. A series of cylindrical smoke-funnels
of increasing diameter, terminated below by truncated cones,
completes the chimney. The annular spaces between the
various funnels introduce air, and by cooling the smoke
render the combustion more complete and the draught more
regular. The enlargement of that part of the damper where
the register is placed prevents the contraction of the orifice
by which the smoke escapes. This arrangement is the best
for burners with five, four, and three wicks, but it is not
indispensable for burners of two wicks and one wick.
The principle of the cylindro-conical burners with outer concentric gas-
air- tube has permitted us to construct gas-burners with con- bl]
centric crowns giving very satisfactory combustion. Fig. 3,
Plate XXXVI, shows the arrangement of a four-crown
burner. It will be remarked that each of the crowns is fed
at the two extremities of the same diameter, and that a
special cock regulates the flow of gas to each crown. These
burners have worked very well, and do not heat to any great
degree.
REMARK. — Fig, 3, Plate XXXIII, shows that the chimney
of the modified Fresnel burners is supported on a plate by
means of three ears. This system, adopted by the French
administration, has the disadvantage of great instability ;
the chimney cannot be exactly centered on the burner 5 be-
sides, the chimneys not being exactly set below, there are
no means of getting them quite perpendicular. We prefer
the use of the old chimney-holders with movable grates on
the inside, by means of which the chimney can be exactly
centered and solidly held.
LIGHT-HOUSES AT THE MOUTH OF THE SEINE
When at the Depot des Pliares, M. Allard kindly gave me
a letter to M. Arnoux, the engineer (des ponts et chaussees,)
who is in charge of the administration of all public works
(including the light-houses) on the left bank of the Lower
Seine, aud I proceeded by rail through Normandy to Hon-
fleur, stopping at Eouen to see that ancient city, and espe-
cially the interesting antiquities in its celebrated museum.
M. Arnoux received me with great politeness, and I had
an excellent opportunity of inspecting the lights of PHdpital
and Fatouville, and the pier-light at Honfleur.
216 EUROPEAN LIGHT-HOUSE SYSTEMS.
n the The light-keepers in the French service are known as
horuse service? *" masters (maitres dephare) and keepers, (gar diem.)
of keepers!1 ment The^ are appointed by the prefect or chief civil officer of
the department on the nomination of the engineer of the
district, who is charged with the river and harbor works,
including the light-houses. Men who have served as sol
diers and sailors are given the preference.
For appointment the following requisites are necessary :
1st. They must be French, and between twenty-one and
forty years of age.
2d. They must be free from all infirmities which would
prevent an active daily life.
3d. They must present a certificate of good moral char-
acter.
4th. They must know how to read and write, and have
an elementary knowledge of arithmetic.
salaries. The annual salary of masters of lights is fixed at 1,000
francs, ($200.) The ordinary keepers are divided into six
classes, salaried as follows: First class, 850 francs, ($170;)
second class, 775 francs, ($155;) third class, 700 francs,
($140 ;) fourth class, 625 francs, ($125 ;) fifth class, 550 francs,
Fuel and ra- ($110 ;) sixth class, 475 francs, ($95.) There is also allowed
to each master and keeper a certain quantity of wood or coal
for heating purposes/and the master and keepers of lights
isolated by the sea receive indemnities for sea-rations.
The salaries and indemnities are paid monthly. Fuel is
furnished in kind and according to the decision of the engi-
neers. Salaries of masters and keepers are subject to a de-
duction of 5 per cent., and these employes are entitled to
retiring pensions derived from this fund. An oath must
be taken by masters and keepers immediately after their
appointment in order that they may be held responsible, if
any dereliction is committed in the establishment to which
they are attached.
Number of ^De number and classes of keepers attached to each light
aordSs is nxed ^v ministerial decision on the recommendation of
oi lights. the engineer, approved by the prefect and the director of the
light-house service. The number is never less than three
for first-order lights, and two for those of the second and
third orders.
Maitres des Tlie masters are charged with the supervision of the serv-
phares. jce of severai lights or beacons. The title (maitre de phare)
can also be granted to those of the principal keepers (chefs
gardiens) who have merited it by exceptional service. At
the lights served by several keepers and where there is no
EUROPEAN LIGHT-HOUSE SYSTEMS. 217
master one of the former takes the title of principal, (chef.)
In case of his absence the second keeper takes his place.
The masters and principal keepers are particularly respon-
sible for the entire service of the lights and the receipt of
supplies. They are charged with the keeping of the regis-
ters and the correspondence.
The other keepers owe obedience to the master in every-
thing that concerns the service, but have the right of appeal
to the engineer.
The principal keepers assist in cleaning the apparatus,
and take their watch the same as the others.
The masters are not held to this service, but they are re-
quired to visit the light at least twice each night, and, by
decision of the engineer, they can be ordered to temporarily
perform the duties of principal keeper when circumstances
render it necessary.
Every year, on recommendation of the engineer-in-chief, Bonus paid to
a bonus not exceeding a month's salary may be allowed by eServ
the prefect to the most meritorious keepers, the number re-
ceiving such bonus not to exceed one-fifth of the total
number of keepers in the department. Masters and keepers
may be punished or removed by the prefect^ on the report
of the engineer-in-chief.
The service of beacons of secondary importance may be service of infe-
confided to persons who are not regularly in the light-house rior bcacous
service.
PHARE DE L'HOPITAL.
This light, so named from its proximity to the ancient
hospital at Honfleur, is of the third order, fixed. It is a
handsome structure of granite, and on both the exterior Description.
and interior no expense has been spared in the way of
architectural effect and fine finish.
The entrance is very imposing, and bears above it the
inscription, " Stella Maris." The interior of the structure
is lined with granite ; although there is no air-space in the
interior of the walls, they appeared to be perfectly dry.
Directly below the watch-room is a bed-room, furnished sleeping - room
with a neat bed with hangings and other furniture, for the in tower
occupation of the keeper not on watch, for it is a rule of
the French service that there must be always two keepers
in the tower during the exhibition of the light. In cases
where there are three keepers at a station, one of them can
remain with his family at the dwelling, but when there are
but two keepers, neither can absent himself from the tower
at night.
218 EUROPEAN LIGHT-HOUSE SYSTEMS.
watch-room. The watch-room at this station was neatly furnished with
a table and easy chairs, and was nicely paved and lined
with a pretty imitation of variegated marble.
^Keepers dwell- rphe dwelling, which is at some distance from the tower,
is also a handsome building, with neatly painted walls and
ceilings. Each keeper is allowed a kitchen and two bed-
rooms, besides certain standing furniture, as in the English
service ; and a list is framed and hung in each room show-
ing what furniture therein belongs to the government and
the principal keeper is responsible for. This furniture, made
of hard wood, is strong and durable.
The family is not recognized in the supply of furniture,
the kitchen and one bed-room only for each keeper being
furnished by the government.
Rooms fitted tip In the dwelling are also fitted up rooms for the engineer
tor district offi- „ ., _. . . . , . .
cers. of the district and one for the conducteur, (assistant engi-
ciutiesV.110 'ur> neer,) who is a subordinate of the engineer, and whose espe-
cial business it is to attend to the lights of the district,
taking care that they are properly exhibited and the build-
ings and lenticular apparatus kept at the highest state of
order and efficiency, while the engineer exercises a general
supervision.
Number of There are at this light three keepers; one of them has the
title of maitre de pliare and the other two are cliefs-gardiens,
all of higher rank and rate of pay than ordinary keepers.
These ranks they had attained by long and faithful service.
It should be noted that in the French light-houses the
keepers are not promoted and changed from station to sta-
tion, as in the English service, but have a chance for pro-
motion only at the stations to which they are first appointed.
Mineral -on to At the date of my visit the illumiuant at the Pliare de
VHdpital was colza, but mineral-oil and a lamp for its use
had been received at the station, and orders to make the
change of lamps and illuminants were daily expected.
The mineral-oil was to be kept in the store-room at the
dwelling, in wooden reservoirs lined with zinc, and I found
that the French use much less precaution in storing it than
do the English, who are building detached vaulted maga-
zines of masonry for this purpose. The English also use
sheet-iron cans or butts for reservoirs as a substitute for
tin, which is not considered as good for the preservation of
the oil.
FEU DE PORT AT HONFLEUR.
This is a small pier light-house of granite, with the focal
plane 20 feet above the base, and shows a red light from a
EUROPEAN LIGHT-HOUSE SYSTEMS. 219
lens of the sixth order, when there are two meters of water
upon the bar. The illuminaut was mineral-oil, and the lamp, niuminant and
as in all the smaller orders of light-houses in France, one of a
the " Maris" pattern, the oil being drawn up by capillary
attraction. The watch-room is neatly furnished with three
linen-covered easy chairs, a table, and curtained bed.
The floor of the main gallery was of stone, as was the stone floor to
. , . , . i j? -i the gallery, and
parapet ; a convenient width was given to the former by pro- extension to the
jectiug the iron railing about six inches beyond the cornice sa
of the tower, a simple mode of obtaining space around the
lanterns of small towers. The keeper's dwelling is a neat
stone structure standing near by on the pier. The keeper,
there being but one at this station, takes care of the light
and also attends to the tide-signals.
I found at the different light- stations which I visited, in
Great Britain as well as in France, that the keepers readily
accepted small gifts of coin in consideration of their services
in showing their light-houses to visitors, and I asked the
conductcur at Honfleur whether any regulation on the sub-
ject existed. He informed me that the acceptance of small
sums from visitors is not forbidden, their service differing
in that respect from our own ; and it may be well to ques-
tion whether our regulation in this respect should not be
abolished, as it is constantly violated and is productive of
no good.
PHARE DE FATOTJVILLE.
This light, which is of the first order, is situated on a high
hill on the left bank of the Seine, three leagues above Hon-
fleur, and forms, with the Phare de VHopital a range or " lead"
to guide clear of the "Batier " Shoals, ten miles distant from
Honfleur. It is under the general superintendence of the
engineer at Rouen. The tower is of stone, octagonal in Description of
plan, with keepers' dwellings on each side connected with it to
by passages at each story. The entrance to the tower is
quite imposing, the visitor entering a large furnished polyg-
onal hall from which a clear view of the interior of the tower
to the lantern is afforded.
There are three keepers, (one maitre de phare and two Keepers.
gardiens of second class,) two of whom are on duty at night,
the other having the day-watch.
The night-keepers alternate in the service of the light,
one being on watch in the tower while the other sleeps in
the room below.
The gardien who conducted me about the establishment
220 EUROPEAN LIGHT-HOUSE SYSTEMS.
stated that he had been more than twenty years in the serv-
ice, and much longer terms are not infrequent.
^ iiiuminant ana The lamp in use at the time of my visit was a mechanical
or pump lamp, burning colza-oil. The burner had an adjust-
able chimney to regulate the access of the outer current of
air to the flame, but it had not the " button" or the exterior
u deflector" as have the English lamps. Mineral-oil was
shortly to be introduced into this light-house.
Meteorological In tlie watch-rooiu 1 observed a barometer, and outside
observations. the watch-room window were wet and dry bulb thermome-
ters. The principal keeper received 200 francs per annum
for his meteorological observations. A small detached es-
tablishment contained a variety of meteorological instru-
ments, consisting of different kinds of rain-gauges and self-
registering wind-gauges. The extensive grounds about the
light house are ornamented with handsome flower-gardens
and shrubbery, and are inclosed with live hedges.
at At eacb light-house are kept a Visitors' Book, in which are
recorded the names of all visitors ; a Service-Book, in which
the details of the daily service of the light (such as the con-
sumption of oil, the visibility of other lights within range,
&c.) are kept ; and an Engineer's Book, in which are record-
ed the notes of inspection of the superintending or district
engineer.
The service-lamps, three of which are always on hand, are
required to be changed every two weeks, the one that has
just been in use being taken entirely apart and thoroughly
cleaned before it is again used.
PHATCES DE LA HEVE.
From Honfleur, I crossed the mouth of the Seine in a
steamer to Havre. When I left Paris I did not intend to
go farther than Honfleur, and my letters from M. Allard
were only to the engineers of the Corps des Fonts et Gliaus-
sees at that place and at Eouen, but at Honfleur M. Arnoux
kindly gave me a letter to M. Quinette de Kochemout, the
engineer charged with the administration of the public
works, including the lights, on the right bank of the Seine,
. whose office is at Havre.
Unfortunately I did not find M. de Eocheniont at home,
and I took a carriage and proceeded to Sainte Adresse, near
Electric lights, which place, and on Cape la Heve are the celebrated double
electric lights, established respectively in 1863 and 1865,
being the first of that kind in the world.
I arrived at the lights after dark, and requested the
maitre de pliare to show me the establishment, saying that
I had endeavored to find M. de Eochemont, but without
EUROPEAN LIGHT-HOUSE SYSTEMS. 221
success, showing him at the same time the letter addressed
to that gentleman bv M. Arnoux. He would not. however. Refusal of
7 keeper to admit
read the letter, and politely stated that he must refuse to victors after
show me the lights, as he had positive instructions not to
admit any visitors within the station after lighting. He
was inexorable to all my arguments, and I was at length
obliged to yield, and, while praising him for his strict obedi-
ence to orders, could not but regret my unsuccessful journey,
and drive of two leagues back to Havre in the rain at mid-
night, without seeing the interesting objects of my visit. I
mention this circumstance as indicative of the character of
the French light- house keepers as far as I saw them.
At all the stations I visited I found them to be bright,
intelligent, and fond of their profession.
The following morning I again proceeded to Cape la
Heve, and had the gratification of inspecting what is prob-
ably the most extensive light-house station in the world.
The towers are very handsome, and are 65 feet high, their Focal planes,
focal plane being 397 feet above the sea.
The dwellings, engine and machine rooms, &c., occupy
the intervening space, about 300 feet, between the towers.
In the engine-room, which is kept with the utmost neat- Boilers.
ness, are two boilers, which are a combination of the up-
right and horizontal, and of about eight horse-power.
In the machine-room are four magneto-electric machines Magneto - eiec-
made by the Compagnie V Alliance of Paris. One machine/"0 machines-
running with a velocity of four hundred revolutions a min-
ute, supplies each light ; and in case of fog or thick weather
the other machines are added, so that the uncondensed
beam, which in the former case is equal to 200 Carcel-buru- power of un-
ers, (2,000 caudles,) is increased 400 Carcel -burners, or 4,000 condei
candles.
The lanterns which surmounted the towers when oil was Magneto - eiec-
used as the illuminant have been removed, and the magneto- S h?
electric lights are exhibited from what were the watch- watch"rooms-
rooms. Small cylindrical lanterns, about 2 J feet in diameter, Lanterns.
formed of glass, cast specially for this purpose, without any
sash-bars, either vertical or inclined, being projected from
the square seaward angles, and illuminating about 275° of
the horizon.
Figs. 25 and 26* represent in plan and elevation the
electric light-room, which is in two stories, each containing
an entire set of apparatus.
* Figures 25, 26, and 27 have been taken from M. Reynaud's Mtimoire
sur VEclairage des Cotes de France.
222 EUROPEAN LIGHT-HOUSE SYSTEMS.
In Fig. 25 A is the lower room ; B. the stairway of the
tower $ C, steps leading to the upper chamber; D, door
leading to the outside platform ; K K, iron rails for the
regulators ; L, the lantern ; O, the illuminating apparatus;
B, the spare regulator ; S, the luminous beam of rays
emanating from a small lens placed in rear of the focus, and
which throws upon the wall an image of the light. The
Fig. 25.
Plan of lantern and watch -room, La H5ve.
position of this image, with reference to a fixed mark, indi-
cates to the keeper whether the light is in the focus of the
lens, and is of the greatest assistance to him, as it is impos-
sible to look at the light itsejf without injury to the eye, on
account of its dazzling intensity. T T are the conducting
EUROPEAN LIGHT-HOUSE SYSTEMS.
wires ; U, the switch for changing the direction of the cur-
rent ; V, an india-rubber speaking-tube. The arc of visi-
bility of the light is represented by the arc m, n, p.
In Fig. 26 A A represents the illuminating apparatus; B
B, rails for the lamps or regulators ; CO, the conducting- wires;
D D, the switches, and E E, india-rubber speaking-tube.
Fig. 26.
223
Section of lantern and watch-room, La Heve.
Iii each of the lanterns, two at each tower, is placed a
fixed lens three-tenths of a meter in diameter, the size of
the sixth order, shown in Fig. 27, and for each lens there is
a duplicate electric lamp, so that, in effect there are three
reserves in case of accident.
It is found by experience, however, as I was informed by
the maitre de pliare, that a second lamp is only required
224
EUROPEAN LIGHT-HOUSE SYSTEMS.
\vlien changing the charcoal pencils, so that so many re-
serves of lamps are more than are actually necessary e
Fie. 27.
Apparatus
tin plicate.
Optical apparatus, La Heve.
in All the other parts of the apparatus, including the en-
gines, boilers, and machines, are in duplicate, excepting the
cables or wires connecting the magneto-electric machines
with the lamps. These, M. Beynaud afterward informed
me at Paris, it was not thought necessary to duplicate, but
I should infer that it would be well to provide in all cases a
second wire, from the fact that in observing the lights from
the steamer, while crossing the Seine from Honfleur to Havre,
I saw that one of them waxed and waned very perceptibly,
and on my questioning the maUre dephare in regard to it,
he stated that the wire leading to that light was in an imper-
fect condition.
EUROPEAN LIGHT-HOUSE SYSTEMS. 225
In regard to the carbons, I was told that those used for carbousuBedin
fog are much larger than those used in clear weather, in °'
order to provide for the rapid consumption when two mag-
neto-electric machines supply each of the lights; also that
the carbons now obtained in France are much superior to French carbons
,.„,., -,.-, \ , -r i-r\ -i- superior to the
the English, (which were used at La Heve during the war English.
with Germany,) and that with the former the impurities
(which are said to be the only source of danger to this
light) are never so great as to cause its extinguishment,
and they are also not subject to the production of that fine
black dust which I observed at South Foreland and Souter
Point as in a slight degree interfering with the full power
of the dioptric apparatus.
I twill be observed that the only provision at La Heve, for Provision foi
accidents.
the exhibition of an oil-light in case of accident from any
cause to the supply of the electric current to the lamp, is an
oil-lamp in the small lens used for the electric light, pro-
ducing an illumination of but little value for sea-coast
lights of their importance.
I was informed that at Grisuez, on the Straits of Dover, ^ight at cape
where the French government has established another elec- Grisnez
trie light, the old lantern and lens for the use of an oil-lamp
have been retained, the electric light is exhibited from
the watch-room, as at La Heve, and an oil-lamp is always
ready for lighting in the first-order lens in Hie main lantern.
A casualty, such as I have mentioned, requiring the substi- LOSS of light in-
tuition of an oil-lamp for the electric lamp at Grisnez would us
reduce the intensity of the light to 6,300 candles, while at
La Heve it would be reduced from 50,000 to 260 candles in
fair weather, (and from 100,000 to 260 candles in fog,) and
probably even less, as the lens used for electric light is not
suited in any case for the exhibition of an oil-light.
Drawings illustrating the arrangement at Grisnez were
kindly furnished me by Chief Engineer Allard, and are re-
produced in Plate XLVI.
Neither the electric light at La Heve, nor those of Souter
Point or South Foreland, which I saw in England, are suffi-
ciently high to make necessary the plan which I am informed
by General Sherman has been adopted at the new electric Electric light
light-house at Port Said, at the Mediterranean entrance to
the Suez Canal, that of providing for the tower an elevator
or " lift " which is operated by the steam-power used to
drive the magneto-electric machines.
Up to the present time^there have been established nine
electric light-houses, viz :
S. Ex. 54 - 15
EUROPEAN LIGHT-HOUSE SYSTEMS.
In France, two fixed lights at La Heve, and a revolving
light at Grisnez;
In England, a fixed light at Dungeuess, two fixed lights at
South Foreland, and a revolving light at Souter Point ;
In Egypt, a revolving light at Port Said ;
In Bussia, a fixed light at Odessa.
The following excellent paper, which I have found in the
Annales des Pont set Chaussees, givesa clear exposition of the
electric sea-coast lights at La Heve.
[Translation.]
DESCRIPTION OF THE ELECTRIC LIGHT-HOUSES AT LA HEVE
BY M. QUINETTE DE ROCHEMONT,
Engineer des Fonts et Chaussees.
Dates of con- The light-houses of La Heve, constructed during the lat
rfgSftogf andter part of last century, were lighted for the first time in
1774; wood-fires were then used. In 1810, lamps with re-
flectors were introduced, which, in 1845, were replaced by
dioptric apparatus. A final change has been recently effected
by the introduction of the electric light.
The application of the electric light to light-houses had
Use of electric ,
piles. already been an object of investigation for a long time.
Currents produced by electric piles were first tried, but their
intensity very rapidly decreased when the apparatus had
been in operation for some time ; the expense was consid-
erable, and, besides, it appeared rather hazardous to confide
to ordinary keepers the care of keeping and regulating the
piles. The system based on induction currents gave, on the
contrary, very good results, in experiments made at tbe Cen-
tral Light-House Workshops at Paris ; so that in 1863 the
Test of electric Minister of Public Works decided that one of thelight-houses
2?ilH^e.madeofLaBeve should be iUuminated provisionally by electric
light as a test. As the experiment confirmed the anticipa-
tions, electric illumination was definitively applied to both
light-houses toward the end of 1865.
Descr- tion of ^ne currents are produced by magneto-electric machines
the apparatus, worked by steam-engines, and are carried by conducting-
cables to the regulators, or electric lamps, used to regulate
the separatior of the carbon points, between which the light
is produced. The magneto-electric machines and the en-
gines are placed in the center of the keepers' dwelling, in
two rooms fitted up for that purpose. (See Plates XXXVII,
XXXVIII, and XXXIX.)
nX
ro
"C
I
^y
EUROPEAN LIGHT-HOUSE SYSTEMS. 227
The steam-engines are two iu number, and present no pe- steam engines.
culiarity worthy of notice, as they belong to the common
stationary class with locomotive-boiler of eight horse-po^er.
They are certified as capable of resisting a pressure of 70
pounds to the square inch. But one engine is generally
used at a time, as it is sufficient to work two magneto-elec-
tric machines. At first it was thought necessary to keep
the second engine with banked fires in case of accident to
the first, but practice has shown that this precaution was
needless. The motion is conveyed from the steam-engines
to the machines by belts and an intermediate shaft. (Plates
XXXVIII and XXXIX.)
The magneto-electric machines were furnished by the Al- tri^5faDc^,eslec"
liance Company. They are composed (Plates XL, XLI, and
XLII) of a cast-iron frame on which are placed mahogany
cross-pieces which serve as supports to seven parallel series
of compound magnets, all of which converge toward the
central axis of the frame. The magnets of the two outer
series are formed of three superposed plates, curved horse-
shoe shape, the others of six plates. They are so arranged
that the poles nearest each other, both horizontally and ver-
tically, are always of opposite signs. The six- plate magnets
are of a power of 145 to 155 pounds, the three-plate, about
75 pounds. Between the seven rows of magnets, there re-
volve six bronze disks, (Plate XLIII,Figs. 1 and 2,) mounted
on an axis supported by the frame. On each of these disks,
sixteen induction-spools are fixed by bronze clamps and
screws. (Plate XLIII, Figs. 10 and 15.) Each spool (Plate
XLIII, Figs. 10-14) is a tube of soft iron about one- third of
an inch thick, 1J inches in exterior diameter, and 3f inches
long, slit radially so as to more quickly lose its magnetism.
Each tube is wound with eight copper wires one- twenty-fifth
of an inch in diameter and about 50 feet long, so that there
are about 400 feet of wire wound around the spool. These
wires are covered with cotton and insulated by asphalt dis-
solved iu spirits of turpentine ; they are wound in the same
direction on all the spools.
The best method of placing the spools has been deter- Method 'of
placing the
mined by experiment and trial ; a certain number of ex- spools,
tremities of wires of the same sign or denomination are
brought together, and an equal number of extremities of the
opposite sign. All the extremities of one sign communicate
with the central axis of the machine, all of the other sign
with a metallic sleeve fixed on the axis but insulated from
it by a plate of India rubber placed concentrically and joined
to two other perpendicular plates. (Plate XLIII, Figs. 5-8.)
228 EUROPEAN LIGHT-HOUSE SYSTEMS.
The shaft and sleeve revolve in journal-boxes (Plate' XLIII,
Figs. 5, 6, 9) insulated from the rest of the frame by plates
of vulcanized rubber. From these boxes and the axis start
the wires which transmit the currents generated by the ma-
chine.
induction -cor- Induction-currents are produced whenever the spools
either approach or leave the poles of the magnets. Thus
there are sixteen changes of direction of the current to each
revolution of the cylinder ; and the wires are therefore alter-
nately traversed by currents of opposite direction and a
series of discontinuous sparks is obtained. The eye, how-
ever, perceives no interval, for the number of sparks ex-
ceeds 100 per second, since the magneto-electric machines
make from 390 to 400 revolutions per minute.
Gron.pingof Four magneto-electric machines (Plates XXXVIII,
XXXIX, XL, XLI, XLII) have been set up. They are
grouped two and two, each group connected with one of the
lights. Under ordinary circumstances one steam-engine
works two machines, one of each group, but during a fog,
when it is wished to increase the intensity of the lights,
each group of machines is worked by an engine. For this
purpose the shaft for transmitting the motion is of two
parts, which are connected or disconnected at pleasure, as
either ordinary or double light is wished, (Plate XLII, and
Plate XLIII, Figs. 3, 4, and 16.) In the latter case the two
machines of the same group are connected.
switches. Accordiugas it is wished to use one, the other, or both oi
the machines connected with one light-house, it is necessary
to change the points of attachment of the conducting- wires.
In order to avoid the mistakes which might result, M. Joseph
Yan Malderen, superintending engineer of the Alliance
Company, has contrived a most ingenious switch, placed in
the machine-room, (Plate XLIY, Figs. 1 to 4.) I*rom
this switch alone proceeds the cable conducting the electric
currents. This cable is composed of three wires, one of
which, /?, communicates directly with the wire b, uniting
the axes of one of the groups of machines, while the two
others, a and ^, proceed from buttons at the lower part of
the switch. The wires a and c, coming from the journal-
boxes of the machines, are brought to two buttons at the
upper part of the switch.
The communication between vthe wires a or c (Plate XLIY,
between the-,. _. , . , i TIJP -i •
wires. Fig. 3) and the wire «, which, when a light of ordinary in-
tensity is required, is always the one which conducts the
current to the lights, is through a forked piece of metal, one
end of which is attached by a pin to the upper button which
EUROPEAN LIGHT-HOUSE SYSTEMS. 229
corresponds to the machine then in operation. On the con-
trary, when a light of double intensity is wished, the cur-
rents arriving at the upper buttons pass to the wires a and
Y through two straight rods, (Plate XLIY, Fig. 1,) and do
not meet until they reach the interior of the lamp. Thus
no displacement of the wires need be feared, as all are
permanently attached to the machines or switches, the
switch-key being all that it is necessary to touch. Each
cable is carried underground to the light-house, thence
through the stairway to the lantern.
In order to avoid extinctions which might result from ac- Duplicate op-
cidents to the regulators, it has been thought necessary totic
have in each light-house two optical apparatus, one above
the other, and for each two lamps. These lamps slide on
rails fastened to a cast-iron plate, and can thusbe movedinto
exact position.
As it was also wished to avoid displacing the conducting second switch.
wires in the light-house lanterns, a second switch is used,
by which the light can be doubled on either stage at will
without moving the wires. (Plate XLIV , Figs. 5 and 6.)
The wire /9, corning from the axes of the two machines of
the same group, connects directly with the lower cast-iron
table, and the communication between the two tables is
through one of the uprights of the lantern, also of cast
iron. The current passes directly from the table into the
lamp to reach the upper carbon point, as will be seen here-
after. The wire « communicates with a large copper bolt,
A, (Plate XLIV, Figs, o and 6) by the metallic plate on
which the bolt slides. The wire Y communicates in the same
way with another bolt, B, sliding vertically like the large
one, from which, moreover, it is magnetically insulated by
an ivory handle.
When the bolts are pushed down, the currents arrive by
the wires « and y, pass into the wires a1 and •/, and go to the
lower stage ; on the contrary, if the bolts are pushed up, the
currents pass into the wires a" and /', and thus reach the
upper stage. If the light is of ordinary intensity, there is
no current in the wire ^, and consequently none in the wires
Y1 and Y"- The currents from the wires a1 or a" reach the
lamp through a flat metallic spring placed above the cast-
iron plate on which the lamp rests. In case of double light
the currents from the wires Y' or Y" reach the interior of the
lamp by a second spring placed at the side of the first.
In this way, when double light is used, only one of the use of siugie
stages of the lantern is lighted. Experience has shown that doifbfe6 light °is
it is better to give double light on one stage than ordinary n£
230 EUROPEAN LIGHT-HOUSE SYSTEMS.
light on both, though at little distance the two lights (sepa-
rated about 7 feet) appear as one.
Lamps, or eiec- - Serrin's regulators, the only ones used at La Heve, (Plate
trie rcguuitory. __.__ __ .
XL V ) are composed of two point-holders, each attached
to a vertical rod which slides in a guide- tube. The rods are
so arranged that when the upper one descends by its weight
the other rises. To effect this, the upper rod in descending
pulls the chain A, one end of which is attached to the lower
end of the rod and the other to a pulley, 0. This pulley, in
turning, winds up another chain, B, attached to the lower
end of the lower point-holder. Thus both rods move to-
gether 5 but, as it has been found that the lower carbon
point consumes somewhat more rapidly than the other, the
pulley 0 has two barrels of slightly different diameter $ ex-
perience has shown that they should be to each other as 100
to 108 to keep the luminous point always at the same height.
The motion of the pulley is transmitted by clock-work to the
fly-wheel D, used to moderate the movement of the point-
holders when they approach each other, impelled by the
weight of the upper rod.
The lower guide-tube is carried by an oscillating parallelo-
gram, MNOP, affected by two forces acting in opposite
directions ; one, the tension of the spiral spring E, which
raises it ; the other, the action of the electro-magnets S, on
the armature Q attached to the parallelogram, which lowers
it. When the lamp is in use and the points are at a proper
distance from 'each other, the armature Q is attracted by
the electro-magnets 5 the parallelogram descends, the pawl
F, carried thereon, engages the ratchet- wheel E, mounted on
the same axis as the fly-wheel D, and the points can no
longer approach each other. As the points consume, their
separation increases, and, consequently, the intensity of the
current traversing the electro-magnets decreases : the arma-
ture is attracted with less force, and the parallelogram re-
ascends, the pawl F escapes from the ratchet-wheel, and the
two points re-approach, impelled by the upper rod. They
continue to approach until the current has resumed its nor-
mal intensity, when the parallelogram redescends, attracted
by tfre magnets. The points approach about one-twen-
ty-fifth of an inch every time a tooth of the wheel escapes
from the pawl.
By a screw, T, acting on a lever, the tension of the spring
R can be increased or diminished so as to regulate the ac-
tion of the lamp. This tension should, indeed, vary accord-
ing to the intensity of the current passing about the mag-
nets S, as these two forces should be in equilibrium when
o
r O
n C
O C/>
H n
2 c/>
o
_ O
n
X
EUROPEAN LIGHT-HOUSE SYSTEMS. 231
the points are a proper distance apart ; the voltaic arc can
thus be kept of a constant length.
As we have already stated, the currents enter the regu- course of the
lator by the base-plate and through either one or two springs
placed beneath, as either ordinary or double light is required-
In the former case the current passes from one of the springs
into one of two pieces, shown together at Y; thence around
the two magnets S, through the piece XX, and reaches the
oscillating tube and the lower point-holder. In the second
case, the other current of the same denomination, conducted
by the wires / or/7, passes from the second spring into the
second piece at Y, and attains the piece V, where it meets
the first current, without having passed about the electro-
magnets. The current of the contrary sign passes from the
base-plate through all the other parts of the lamp to reach
the upper point-holder. The parts traversed by currents of
contrary signs are insulated from each other by vulcanized
rubber and ivory. To assure good working of the lamp, M.
Serrin has contrived some devices which we will point out. 1" °
When the upper rod is raised, the pulley C (on which are
wound the chains connecting the ends of the rod) revolves;
but, to prevent forcing the clock-work, a ratchet-wheel, G,
is placed on the same axis as the first cog-wheel.
The two screws H and I, which meet two pieces on the
side NO of the parallelogram, limit its motion.
By the screw K (Plate XLV, Fig. 1) the upper rod can be
raised or lowered to alter the position of the luminous
point. In his last lamps M. Serrin has adopted a much
better device, by which the luminous point can be placed in
exact position by moving both carbons at once, thus prevent-
ing any decrease of light. For this purpose the chains A and
B are run over a little auxiliary pulley which can be moved
up or down by a screw and lever so as to raise or lower both
points the same distance at the same time. This device is
applied to four of the lamps in use at La Heve.
A small gauge, Z, movable around the upper rod, indicates
the exact height at which to place the gap between the car-
bons; that is to say, the luminous point. By the two screws
L and I/ the carbon-points can be adjusted exactly opposite
each other by moving the upper point in a direction either
parallel or perpendicular to the plane of the two rods.
Finally, to prevent the point-holders burning when the
carbon is consumed they stop at a distance of about 2J inches
from each other, as then the upper rod strikes the base of
the lamp and can go no farther.
232 EUROPEAN LIGHT-HOUSE SYSTEMS.
Another regulator, invented by M. Foucault and con
structed by M. Dubosq, has also been tried. It was, how-
ever, not well adapted to be placed on a cast-iron table, and
was twice broken within a short time, in consequence of a
too great separation of the carbon points.* Its use was
then abandoned.
carbon points. The carbon points used for electric illumination are man-
ufactured from the residue contained in gas-retorts. They
are about 10 inches long and from one-third to one-half an
inch thick, according as they are used for ordinary or double
light.
optical appa- The optical apparatus, Fig. 27, are about one foot in
diameter $ the catadioptric rings are symmetrical, both
above and below, on account of the form of the points and
fhe luminous center. The luminous rays are sent from the
rings tangentially to the surface of the sea. The joints of
the rings are placed in a direction parallel to that taki n by
the rays after their refraction. The luminous center being
of very small dimensions, (about two-fifths of an inch by
two-fifths to three-fifths of an inch,) the lantern can have
no sash-bars, as the occupation of a part of the horizon.
which they would produce must be avoided.
Tll° divergence of the luminous rays is about 6°; about
^6 same as tbat of a first-order oil-light, It is indis-
.oint, pensable that the luminous point should remain in ex-
actly the proper position in the optical apparatus, as a
vertical displacement of one-fifth of an inch would raise or
lower the luminous beam 2°. To assure a correct position
for the luminous center, there has been attached to the
edge of the optical apparatus a small lens, which throws
the image of the points on a screen placed at the other end
of the service-room. This image should be in such a posi-
tion that the gap between the points appears on a line pre-
viously traced on the screen. If it does not, the position
of the luminous center should be adjusted as has been indi-
cated above. The image is magnified 22 diameters.
The lights of La Heve illuminate three-fourths of the
horizon. The lanterns and service-rooms are at the un-
lighted angle.
other aids. Oil-lam ps with large burners can be placed in the center
of the optical apparatus if there should occur an accident
_ preventing the production of electric light ; in such case one
of these burners is placed on each stage of the lantern.
M. Dubosq has since placed a ^top-piece to prevent the too great sepa-
ration of the points; the lamp works with more regularity, but we
have not again used it.
O
I
m
o r
o en
I
<
n
^ >§"
T
EUROPEAN LIGHT-HOUSE SYSTEMS. 233
Each luminous point has about \the intensity of a fourth -
order light $ at a short distance the two lights blend and
appear as one.
Call-bells with dials connect the engine-room and the caii-beiis.
light-house lanterns, so that the engineers and keepers can
communicate with each other. Other bells are placed in
the dwellings of the principal and other keepers.
Water for the steam-engines and for domestic use is kept water.
in cisterns of a total capacity of about 46,000 gallons. It
is rain-water collected from the roofs of the buildings and
from courts paved with asphalt, a total surface of about
2,000 square yards. It is pumped by the engines into a
tank near the engine-room, (Plate XXXVIII.) There is a
small workshop, so that the engineers can make all current
repairs which do not require special artisans or implements.
In charge of the lights there is a principal keeper, (mditre organization of
dephare,) who has under his orders six assistants, (gardiens,) the servicc-
two of whom are engineers, whose special duty is to attend
to the steam-engines j the others attend the lamps. The
engineers have the title and rank of keepers (gardiens) of
the first class, but as their service is much more arduous
than that of their comrades, an extra compensation is
allowed them at the end of the year if they have given sat-
isfaction. With a view to subordination and harmony of
relations at the lights, it seemed better to give these em-
ployes a relative rank rather than to exclude them from the
service by giving them the title of engineers.
Since commencing the use of electricity (November 1, Accitloilts
1805) several accidents and a few extinctions have occurred,
We give below a complete list.
March o, 1866. — The suspension-chain of the upper rod of
one of the electric regulators breaks.
A2)ril 8. — Light out five to six minutes, in consequence of
the slipping off of several of the belts.
July 12. — The heel-screw of one of the magnets of ma-
chine No. 22 becoming loose, rubs against the spools of one
series and injures them so that several have to be replaced.
As this accident happened at the moment of setting the
machine in motion, no extinction resulted.
July 27, September 5, September 8, September 12. — The sus-
pension-chains of the upper rod of four regulators break ;
the damaged lamp being immediately replaced by another,
the light was out but a few seconds.
October 2. — Four mahogany cross-pieces of machine No.
19 are broken ; four spools are injured. The reserve machine
234 EUROPEAN LIGHT-HOUSE SYSTEMS.
being immediately set in motion, tbe light was out bat a
short time.
January 11, 1867. — The suspension-chain of the lower rod
of a regulator breaks.
March 9. — Light out 3 minutes, the belt of the engine
having slipped off.
March 17. — Light out 3 minutes, the fire-grates of the en-
gine having fallen.
March 25. — Southern light out 7 minutes and 3 minutes.
March 29 to 30. — At 10.35 p. m. the southern light out,
Being unable to relight it, oil-lamps are placed in the lens-
apparatus. At 2.35 a. m., on again trying the electric light,
it works. Electric light out about 4 hours.
May 25. — At 12.5 a. m. the water-pipe of the engine bursts,
the pressure falls; reflectors are lighted at 12.20. The dam-
age having been repaired, the electric light is re- established
at 1.5.
November 20. — Southern light out 5 minutes, caused by
the slipping off of the belt of the magneto-electric machine.
January 5, 18G8. — Southern light out 9 minutes.
March 3. — Light out 7 minutes, caused by the belt of the
steam-engine having twice slipped off.
March 19. — Light out 2 minutes. The pin of the fly-wheel
becoming loose, it was necessary to tighten it.
May 4. — Southern light out 3 minutes, the belt of the
magneto-electric machine falling off at the time of firing up
the southern engine.
October 26. — At the moment of lighting, the joint of the
steam-gauge of the southern engine bursts. The fires of the
northern engine are lighted, but before steam is up the acci-
dent is repaired, so that the hour of lighting is not delayed.
October 30, 1869.— Northern light out 15 minutes, the
keeper having fallen asleep.
In addition to the extinctions mentioned above, which
were the result of accidents, there occur every night a*few
others of short duration, which cannot be avoided. When
the lamps are changed, for instance, the light is out a few
seconds ; also, when double light is to be produced after
ordinary light, or vice versa, it is necessary to throw in or
out of gear the two parts of the shaft connecting the two
magneto-electric machines of the same group, so the light
is out 2 to 3 minutes.
rpo recapitulate, we find that in four years there have
occurred —
LIGHTHOUSES OF LA
ELECTRIC LIGHTS.
MAGNETO-ELECTRIC MACHINE
SIDE ELEVATION.
PLATE XLI
SCALE.
tJtc/lft Jj» V f j Q 7
TJ1S!
EUROPEAN LIGHT-HOUSE SYSTEMS.
Three extinctions of 2 minutes, 3 minutes, and 1 hour
duration, caused by accidents to the steam-engine.
Five extinctions of from 3 to 7 minutes, caused by the
slipping off of the belts. These extinctions were the result
of the negligence of the keepers. Measures have been taken
to prevent similar occurrences.
Two accidents to the magneto-electric machines, from
which no extinctions of consequence resulted, as the machine
in reserve was immediately set in operation.
Six lamps were sent back to Paris in consequence of the
breaking of the suspension-chain of one of the carbon
holders, but the extinctions caused by these accidents are
not worthy of mention.
Four extinctions of 3, 7, 9 minutes, and 4 hours' duration,
the causes of which we have not been able to determine.
One extinction of 15 minutes, resulting from the sleep of
a keeper.
The extinctions originating from the steam-engines, or
the slipping off of belts, offer nothing particularly worthy
of notice ; one only exceeded 7 minutes, and was the result
of the breaking of the water-pipe ; the others are mainly
attributable to the negligence of the machinists.
The accidents which occurred to the magneto-electric ma- causes
diines rendered it necessary for M. Joseph Van-Maldereu,
superintending engineer of the Alliance Company, to makechiues-
a journey to Havre, in order to attend to their reparation.
The second of these accidents was probably caused by the
falling out of one of the wedges used for keeping the mag-
nets in position, and the magnet having nothing to hold it,
hit the wheel carrying the spools.
The breaking of the suspension-chain of one of the carbon- Cause of break-
holders (an accident which occurred six times) was caused sum-chain oi>ptie,
by these chains passing too near other parts from which ca
they should have been separated, and thus becoming heated.
M. Serriu has easily succeeded in remedying these disad-
vantages, and they will not again occur.
The extinctions of 7, 3. and 9 minutes, occurring to the Extinctions b\-
.. .. , J ... unknown causes.
southern light, are due to causes which we have been unable
to ascertain $ it is probable that they were the consequences
of a lack of vigilance on the pact of the keepers. In regard
to the extinction of four hours' duration, we are unable to
attribute its cause to anything but malice on the part of
some one, for the light went out at 10.35 p. m., and it was
impossible to relight it, as the currents no longer reached
the lantern. Subsequently, however, when we arrived,
about 2 o'clock a. m., the light was immediately restored
236 EUROPEAN LIGHT-HOUSE SYSTEMS.
without anything being done to the machines. The two
conducting-wires had probably been connected at some
point before reaching the lantern, and the circuit being
thus closed, the currents no longer reached the lamp. It
is proper, however, to state that an open investigation on
this subject gave no result.
Decrease m the The list given above will show that accidents happen
Ss.er C1" less and less frequently. Such a result might have been
foreseen to a certain extent ; still it is well to prove it. As
the keepers become better and better acquainted with the
management of the apparatus of which they have charge,
they become less surprised at incidents which may occur,
and can immediately apply the proper remedies to a state
of things which might become grave if allowed to continue.
Thus, one of the engineers, who has been in the light-houses
since the end of 1863, has never had any accidents on his
watch, while others serving during the same period have
had only too many.
Substitution oi In addition to the accidents mentioned above, it was
engines. found necessary, at the beginning of 1868, to substitute new
steam-engines for those which had been in the service since
1865, and likewise to replace some of the journal boxes of
the magneto-electric machines.
ow engines iu- ^ae old steam-engines were furnished by M. Bouffet:
sufficient.
they were of five horse-power and certified for a pressure of
six atmospheres. This was found insufficient for the labor
they had to perform. From experiments made on their
greatest power, in March, 1866, the results, indeed, showed
that they were unable to develop continuously more than
six horse-power ; that, under these conditions, they gave
one hundred revolutions per minute, and the mean pressure
in the boiler was five and a half, without ever reaching five
and three-quarters atmospheres. Now, to produce a light
of normal intensity, these engines are required to make one
hundred revolutions, and the pressure was five and a quar-
ter atmospheres. The engines were thus necessarily driven
to the limit of their capacity, which could not be otherwise
than very injurious, resulting in rapid waste. Already, in
1867, a part of the plates of the fire-box, and the pipes of
the southern engine, had to be replaced at an expense of
$385.25. Other repairs made on these engines to prevent
them from heating cost $234.60.
The magneto-electric machines are furnished with the
self-lubricating journal-boxes of Avisse, but in the insula-
ted parts the arbors had the same diameter beyond the jour-
nal-boxes ; the oil was drawn along by centrifugal force, and
EUROPEAN LIGHT-HOUSE SYSTEMS.
237
the bearing was not uniformly lubricated. On this account
the journals did not wear evenly, which was remedied by
grooving the arbor beyond the box. The worn journals
had to be re-turned, and the cushions of the journal-box re-
newed.
Quite a number of different apparatus are combined to causes of ti><>
_ . irregularity o t
produce the electric light; if any are not in proper condi- the light.
tioii they affect the light.
If there is a lack of pressure in the boiler, the magneto-
electric machines run slowly and the light scintillates mark-
edly ; instead of a steady light, the eye perceives successive
flashes.
The bearings of the central shaft of the machines must be
well insulated, as otherwise the light loses in intensity.
In the regulators the separation of the carbon points some-
times varies 5 the light decreases until they return to a
proper position. This disadvantage has been almost en-
tirely obviated by recent modifications made by M. Serrin.
By suitably regulating the tension of the spiral spring the
variations of intensity of the light, as far as depends on the
regulator, may be almost entirely prevented.
.The principal causes of tlie irregularity of light originate want of iiomo-
iu a want of homogeneity of the carbon points and the dis-
placement of the voltaic arc.
The points, as we have already stated, are made of the
carbon deposits of gas-retorts. This is sufficient to explain
their want of homogeneity. They should be hard, well
pressed, and give a very dry sound when broken ; by their
external appearance alone a just estimate of their quality
can be formed. The breaking of the points when in use,
although rare, will sometimes occur; this necessitates a
change of lamp, and therefore an extinction of a few sec-
onds ; it is not practicable, in fact, to wait until the carbon
points re-approach, as the luminous point would then be
displaced. The want of homogeneity of the carbon also
causes a displacement of the luminous point. In order to
remedy this, M. Serrin contrived the mechanism for simul-
taneously lowering and raising the points. The metallic or
siliceous grains found in the substance of the carbons also
affect the regularity of the light by acting on the voltaic
arc.
It is proper to state, however, that these oscillations of
the light are much stronger and more apparent when
near at hand than when observed at a distance, and that fcanca
they are no serious disadvantage ; under no circumstances
could they be confounded with those of eclipse or scintil-
oscillation of
238 EUROPEAN LIGHT-HOUSE SYSTEMS.
lating lights. These oscillations, moreover, have greatly
diminished, and electric lights may henceforth be consid-
ered as quite steady.
in- Experiments made at the central light-house workshop
show that the mean intensity of the light produced by a six-
disk magneto-electric machine is two hundred burners.
This intensity varies within certain limits, and it was found
necessary to make a great number of experiments in order
to estimate its mean. The luminous center, placed in an
optical apparatus of one foot diameter, gives an intensity
of about five thousand burners.
Expenses of the More than four years having elapsed since the definitive
establishment of electric lights at La Heve, we are enabled
to furnish an exact statement of the annual expenses.
The following table shows the expenses, including sala-
ries. The items are taken from the light-house journal and
from the accounts of the conductor:
o
X
m C
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n
EUROPEAN LIGHT-HOUSE SYSTEMS.
239
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00 ff} CD
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240
EUROPEAN LIGHT-HOUSE SYSTEMS.
Expense of re-
pairs to the ma-
chinery.
Expense for Rain-water is used for steam-engines, but in very dry
water for the en- . , r> -i -i -^ • ±1 i
years it has failed; it is tkeu brought from Samte-Adresse
at au expense of about 40 cents per hundred gallons. This
will explain the item of expense for water in 1860 and 1868.
Before increasing the water-collecting surface, or con-
structing another cistern, we wish to ascertain if the saving
will justify the expense of construction.
The old steam-engines consumed about thirty-four gal-
lons of water per hour ; the new average about forty.
The repairs to the machinery in 1867 and 1868 were con-
siderable on account of the inefficiency of the steam-engines ;
there is every reason to hope that this expense will be
diminished with the new engines, which are much more
powerful ; we have consequently reduced this item in the
last column. Other expenses for supplies and repairs in-
clude stowage of coal and cleaning of cisterns and of the
water-collecting surfaces, washing of linen, and other items
of little consequence. In order to obtain an exact state-
ment of the annual expense incurred for the production of
electric light, it would be necessary to add a certain amount
to the figures mentioned in the preceding table for deterio-
ration of the apparatus. It is proper, however, to state
that there is but little wear to most of the machinery. The
regulators, which have been in use for six years, work as
well as on the first day, the only wear being to the journal-
item of wear to boxes of the magneto-electric machines. Thus, the wear of
be taken into ac-
count. the steam-engines is almost the only item to take into ac-
count. These diminish quite rapidly in value.
Table showing number of hours of illumination and duration of the working
of the engines.
1866.
1867.
1868.
1869.
Average
year.
ED fines workin0"
H. M.
4, 288 55
H. M.
4, 518 33
H. M.
4, 509 47
H. M.
4,496 21
Hrs.
4,540
Magneto-electric machines
3 943 25
4, 152 28
4, 203 47
4,188 06
4, yno
Total hours illumination..
3,872 10
3 789 55
4,087 51
3 989 04
4,142 47
4, 129 01
4, 127 16
4,087 22
4,135
4, 055
Double li^ht used
82 15
98 47
13 46
39 54
60
Time of light- Since May 1, 1867, the time of lighting is a quarter of an
ing and extiu- J
guishing. hour after sunset, and the lights are extinguished a quarter
of an hour before sunrise ; while formerly they were lighted
a quarter of an hour later, and put out a quarter of an hour
earlier; so the total annual illumination is increased 182£
hours. This increase is taken into consideration in the last
column of the preceding table. It occurred in 1868, 1869,
and a part of 1867.
LIGHTHOUSES OF LA HEVE.
ELECTRIC LIGHTS.
MAGNETO-ELECTRIC MACHINES
DETAILS.
PLATE XLIII.
Tig: 15.
EUROPEAN LIGHT-HOUSE SYSTEMS. 241
The steam-engines are fired up about an hour before the
lime of lighting. It takes nearly three-quarters of an hour
to get up steam.
The magneto-electric machines are started about ten min-
utes before the hour of lighting, so that the currents may
be well established.
Double light is produced whenever the fog is so dense Double light.
that keepers at La Heve cannot see the beacon-lights on
the north pier of Havre.
Electric light was twice introduced at La Heve ; in 1863 Ex^<;use ot
and 18G5. At the first period the superstructure of the tem of lighting,
vsouthern light-house was finally modified by substituting for
the glass lantern, mounted on a sub-base, a structure of
stone-work with the lantern in the angle.
Temporary buildings were made for the engines, but these
were demolished in 1865, at which time the lantern of the
northern light-house was also altered, and the engines were
placed in the house formerly used as a dwelling by the
principal keeper, a small building being added in the rear.
Three new dwell ings for the keepers were constructed, as well
as a cistern, and the water-collecting surface was enlarged.
Two sums, one of $6,266.58, the other of $11,676.50, were Expense of
expended for these works ; but these do not include the
price of the steam-engines, magneto-electric machines, regu-
lators, lanterns, cupolas, &c., which were sent from the cen-
tral light-house depot. As the details of these expenses
have no general interest, we shall not give them.
In altering other light-houses the expenses, taking into
account the difference of location, would probably be quite
different.
We shall confine ourselves to giving some details of prices
„ , Cost of special
ot special apparatus, as these prices are almost entirely in- apparatus.
dependent of the situation of light-houses :
The two steam-engines and accessories cost. ... $2, 493 42
That is to say,
Fortwoengines $2,161 60
Two Foucault regulators 77 20
Two chimneys 41 56
Two bed-plates for fly-wheel 56 82
. Feed-pipes and mounting of the x
machinery t 156 24
The feed-pump and water-tank cost 388 31
Shaft 378 76
Six belts, about 48 25
Six magneto-electric machines 9, 339 86
S. Ex. 54 16
242 EUROPEAN LIGHT-HOUSE SYSTEMS
Namely, for —
Four machines $9, 264 00
Columns and copper rods for con-
ductors 56 56
Two counters 19 30
Four switches, with their accessories $77 07
Two eonducting-cables, about ,. . 271 20
Eight regulators, with their accessories 2, 242 66
Namely, for —
Eight regulators „ . . . 1, 544 00
Alteration of first regulator in
1865 119 66
Four cast-iron plates, with the
springs ' 308 80
Expenses for experiments al-
lowed to M. Serrin* 270 20
Four optical apparatus 1, 389 60
Electric bells 262 50
comparison of From December 25, 1863, when the southern light-house
light!10 n was lighted for the first time by electricity, to August 31,
1865, the date when the northern light-house was still light-
ed with oil, it was easy to compare the two modes of pro-
ducing light. At that time the magneto-electric machines
had but four disks ; the intensity of the luminous point was
only 125 burners, and the intensity of the beam sent to the
horizon not more than 3,500 burners when ordinary light
electric fnminous was used. The intensity of the oil -lights was 630 burners.
light. an_t From information obtained in 1865, it seems that the elec-
tric light always was seen before the other, even in clear
weather, t The light of Barfleur was often seen at the same
Raiige of eiec- time as the electric light of La Heve. According to state-
ments of commanders of vessels, this frequently occurs now,
while with the oil-lights it was very rarely observed. The
electric light appears to have had a considerably greater
range. We shall refrain from giving too great emphasis to
a note sent us by a captain of a steamer, who asserts that
in one particular instance, under favorable circumstances,
he did not lose sight of the electric light until at a distance
of forty miles from Havre, after having seen the light of
* Two hundred aud twelve dollars and thirty cents was allowed in
1863, and $57.90 in 1865, to M. Serrirr as compensation for experiments
and models. We mention these items in order to show the exact price
of the regulators ; besides, M. Serriu now sells his apparatus at $280.50,
instead of $193.
t We have more especially consulted the captains of steamers running
toDunkerque, Morlaix, Bordeaux, and the ports of Spain, as they have
more opportunities for observing the lights of La Heve.
LIGHTHOUSES OF LA HEVE.
ELECTRIC LIGHTS.
PLATE XLIV.
SWITCHES.
Bg.4.
mttf
SCALE.
." 0
nFoot.
IVERSI-TT
EUROPEAN LIGHT-HOUSE SYSTEMS. 243
Barfleur for an hour and a half; but we shall call attention
to the following statements, selected from a great number
of others, which confirm the same results :
The electric light has generally been visible at a greater
distance than the other by :
6 to 7 miles according to Captain Fautrel.
4 to 5 miles according to Captain Morisse.
2 — miles according to Captain Lemonnier.
3 — miles according to Captain Kebour.
4 to 6 miles according to captain of the Yilledu Havre.
4 — miles according to Captain Duval.
4 to 5 miles according to the pilot, Lecoq.
5 to 6 miles according to the pilot, Guerrier.
4 — miles according to the pilot, Mazeras.
Some captains corroborate these statements by declar-
ing that, at great distances, when the lights were first seen,
the electric light seemed a little higher than the other. At
some distance there was a notable difference in their bril-
liancy; the electric light appearing white and brilliant, the
other red and smoky. The effect produced was well de-
scribed by the picturesque comparison made by one of the
pilots of Havre, ( Pilot Savalle :) " There is as much differ-
ence between the lights as between a candle and a gas-
light." This effect was moreover distinctly visible from the
north pier of Havre.
The statements agreed still better in regard to the light Light during
during foggy weather. All the captains and pilots con-f(
suited by us declared that during fog there was a great
difference in the range, and they all spoke highly of the
services rendered them by the electric light ; they assured
us emphatically that a large number of vessels had been
able to enter the harbor without difficulty, perceiving the
southern light, while formerly they had been obliged to re-
main outside, the lights not being visible. Even before per-
ceiving the electric light, its presence was marked by the
illumination of the atmosphere surrounding it, audits range
was thus increased, especially in foggy weather. This is an
important advantage of the electric light, and may be of
great practical utility, as is shown by a letter from Captain
Delbeke of the steamer La Flandre, which we give below, as
it well states the facts :
" In the nights of the 26th and 27th of February, 1865, I statement of
,,,..- ..„ ., ., , . Captain Delbeke.
was doubling Cape Antifer at 1 a. m., three miles out, in '
eighteen fathoms of water, the point of the cape bearing S.
E. J E. The weather was very foggy on shore, but an ex-
perienced seaman could make out the point well enough to
determine his position. 1 was then eleven miles and a half
244
EUROPEAN LIGHT-HOUSE SYSTEMS.
from the Fecamp light, which was not visible for the fog,
and twelve miles from LaHeve lights, toward which I could
steer, as I saw, tot the lights themselves, but their reflec-
tion. Approaching in order to make the channel and enter
the inner roadstead of Havre, (it was then 3 a. m.,) I clearly
saw the electric light and could not see the ordinary light."
Diminished dif- The difference of range between electric and oil lights
£lringefog. rauge diminishes rapidly when the fog thickens. Inspector-Gen-
eral Keynaud. in a report dated May 20, 18G3, estimated the
comparative range of a fixed light of the first order illumi-
nated by oil or electricity as follows :
Table of com-
parative range.
Range of the
unit of light.
Range in kilometers of a
first-order fixed light.
Oil : inten-
sity, 630
units.
Electricity :
intensity,
3,500 units.
Kilometers.
0.1
0.5
1
2
3
4
5
Kilometers.
0.160
0.93
2.08
4.89
8.45
12.9
18.7
Kilometers.
0.177
1.06
2.40
5.77
10.2
15.9
23.4
It is seen that even in a slight fog the electric light is but
little superior in range in spite of the great difference of
luminous intensity, but it gains in proportion to the clear-
ness of the atmosphere. This result is also shown by the
following table, the result of observations made in 1864 at
the light-houses of Honfleur, Fatouviile, and Ver: *
Table of results
of comparative
observations.
Places of obser-
vation.
Distances.
Light ob-
served.
Proportion of
visibility in
100 observa-
tions.
Proportional
value of elec-
tricity.
Miles.
< Oil
88 ?
Houfleur
9.32
1. 045
> Electricity,
j Oil
92 s
77 ?
Fatouviile
13.36
) Electricity.
(Oil
79 5
33 )
1. 026
Ver
28. 89
A. >
1.24
} Electricity.
41 $
c d b y vertical
sash-bars.
Light obstruct- The observations made at Fatouviile seem afnomalous $
but this is easily explained, for one of the uprights of the
* This table and the remarks following are taken from the report of
M. Reynaud, inspector-general, and dated March 31, 1866.
EUROPEAN LIGHT-HOUSE SYSTEMS. 245
lantern of the northern light-house was placed in the direc-
tion of the light of Honfleur, thus masking a considerable
part of the light emanating from the apparatus. The range
of the electric light is, moreover, diminished in foggy
weather, on account of its inferior power of penetration.
This arises from the different composition of the two lights,
and is the more marked as the fog thickens. Experiments
made at the central depot have shown, however, that if the
electric light has an intensity two and a half times greater
than a light of colza-oil, it will penetrate fog as well. As
the intensity of the electric lights at La Heve, compared
with an oil-light, for surpasses this proportion, we may be
assured that the electric lights will always be superior in
range.
Since 1865 six-disk machines have been used. The iuteu- use of -six-aisk
-, ., , ,. machines.
sity has thus been considerably increased, and the relative
range of the lights has always surpassed that shown in the
preceding tables.
In order to complete the comparison of the two modes of
producing light, there are yet a few words to be said as to
the expense of each.
At La Heve, as we have already shown, the electric lights comparison of
cost $3,215.29 annually, deterioration of machinery not in- co
eluded. For the same period the oil-lights before the altera-
tion cost $2,828.88, distributed as follows : *
Salaries $820 25
Fuel 77 20
Oil 1, 800 58
Sundry supplies 84 53
Keeping apparatus in order 46 32
The expense is thus greater by $386.41, or about one-
seventh $ but this increase of cost is largely repaid by the
increase of intensity of the lights.
The electric lights of La Heve have this economical ad- " of
vantage, that, while two in number, the expenses are far
from being double what they would be for a single light.
A certain number of expenses are, in fact, common to the
two, or approximately so, especially salaries, the extra com-
pensation and allowance for fuel to the engineers, the coal
for the engines, &c.
This is not the case when oil is used, for then two lights
will cost very nearly double what a single one would in the
same circumstances.
* See M. Reynaud's Memoire sur VEclairage des Cotes de France.
246
EUROPEAN LIGHT-HOUSE SYSTEMS,
Estimated cost
of electric light.
Basing our calculations on the experience of 1863 to 1865,
we estimate the cost of an electric light of 5,000-burner
intensity as follows :
Nature of expense.
Price.
Quantities.
Cost.
Salaries
$834 72
Allowance for fuel
77 20
Bonus to engineers
57 90
Water. . .
71 328 CO
Coal, per ton of 2,240 pounds
$6 18
15, 428
43 23
Coke, per ton of 2,240 pounds
8 69
110,200
434 25
Carbon points
434
393 70
156 33
Cotton-waste. ...
23
308. 56
32 43
Luoricatiucr-oil •
38|
440 80
77 20
Illuminating-oil
27
551
67 55
Grease
25
88 16
10 04
Hemp, white-lead, &c
9 65
Towels, mops, &c.
11 58
Various supplies and repairs to ma-
chinery . ...
156 52
Total
1 968 60
Cost of first-
order oil-light.
co?t°
liht.
The average cost of a first-order oil-light of 630-burner in-
tensity is $1,494.40,* viz:
Three keepers, (two first and one second class) $477 68
Fuel 48 25
Oil - . - .. 903 04
Sundry supplies 42 27
Keeping apparatus in order. 23 16
The electric light would cost about $475 more than the
other, and the expense would therefore be increased nearly
one-third. A comparison of the cost of the unit of light for
oil-consuming and electric lights may easily be made from
the preceding, and the figures given by Inspector-General
Eeynaud are verified. At La Heve, as the expense of the
electric light amounts to $3,215.34 for 4,135 hours7 illunil-
e 4,055 x 5,000+80 x 10,000,
nation, and a mean intensity or - — /T135 —
or 5,097 burners, taking into account the time double light
of was produced; the unit of light sent to the horizon by each
$3,215.34
light-house costs, therefore, 2 x 5 097 x 4 155 = $^.000076.
The cost of the unit of light produced by the oil-con-
* See M. Reynaud's Memoire sur I'ficlairage des Cotes de France.
LIGHTHOUSES OF LA HEVE.
ELECTRIC LIGHTS.
ELECTRIC REGULATOR.
PLATE XLV,
SCALE.
6
EUROPEAN LIGHT-HOUSE SYSTEMS. 247
suming light-houses before their alteration amounts to
r. = $0.000576 * which shows that the unit
£ X oou X o,JUu
of light at the light-houses at La Heve costs about seven
times less than that of oil-consuming lights. If, on the con
trary, we consider a single electric and a single oil consum-
ing light, the unit sent to the horizon would cost for the
former F , or $0.0000952. and for the latter,
O,UUU X 4,-LoO
!n'49t'tnn> or $0.000608. The difference of cost is therefore
GoU x o,yuo
somewhat more.
Conclusion. — Since the first establishment of the electric Reca itulatiou
light, six years ago, sufficient time has elapsed to give an
exact idea of its value for coast illumination.
Navigators acknowledge with pleasure the excellent serv-
, . ,. , . ,, ., , Satisfaction of
ice which the electric lights render them; the advantages navigators,
of the system have been keenly appreciated, the range of
the lights is sensibly increased, especially during somewhat
foggy weather, thus allowing a great number of vessels to
proceed on their course and enter the harbor at night, which
they would not have been able to do with the oil-light.
The light, which at first was not as steady as could be
Steadiness of
wished, acquired a remarkable steadiness, thanks to im- tto light.
provemeuts in the apparatus and the experience acquired
by the keepers. The fears which were entertained, a priori,
on account of the delicacy of some of the apparatus, have
not been justified in practice. Accidents have been rare,
extinctions short and few; two only of the latter during the
period of six years being of notable duration; one, of one
hour, was the consequence of an accident to a steam-en-
gine ; the other, of four hours, seems to have been mali-
ciously caused. Under these circumstances there seems
but little reason to be troubled about possible accidents.
Still there are some disadvantages inherent in the system Disadvantages.
of electric illumination which necessarily limit its applica-
tion. A considerable space is required for the steam-en-
gines and the magneto-electric machinery, for storing coal,
coke, oil, &c., and for collecting and preserving the water
for the engines.
Finally, the repairs of apparatus in use require special
workmen, not usually found in the vicinity of light-houses.
* These calculations suppose the electric light in operation 4,135 hours,
and the oil-consuming lights 3,900 hours, because under these conditions
the expenses were estimated.
248 EUKOPEAN LIGHT-HOUSE SYSTEMS,
The keepers usually can attend only to current repairs; the
more important ones have to be done in workshops better
appointed than those attached to light-houses. In case of
an accident of some importance, the magneto-electric appa-
ratus can only be repaired by the Alliance Company. The
lamps, under the same circumstances, have to be sent to
M. Serrin at Paris. It is true that, as there are several
regulators at the light-houses, one of them may be spared,
so that the rare accidents which occur to these apparatus
never cause but a few seconds' interruption of the light.
Proper situa- We therefore think that in a great number of cases, espe-
t:uu lor electric
cially in those of light-houses in the sea, or distant from
important centers of population, or not easily accessible,
the substitution of electric light for that produced by the
combustion of colza-oil would be disadvantageous, or even
impossible. But as this substitution offers great advan-
tages to navigation, it seems advisable to adopt it for
light-houses favorably situated ; that is to say, where there
is plenty of space, and they are sufficiently near to cities or
easily accessible. The French light-house administration
have already established a second one at Grisnez.
England, after having first tried the electric light at
Dungeness, is about to establish others at South Foreland
and Lowestoft. The attention of other governments is also
drawn to this matter, and it appears probable that the
example of England and France will be followed.
The change will cause a slight increase in the running
expenses, but the difference is not so great as to cause hesi-
tation when the increase of intensity and of range is con-
sidered.
CAPE GRIS-NEZ LIGHTHOUSE.
LLECTRIC LIGHT. PLATE XLVI.
PLAN AND SECTION ,
SHOWING ARRANGEMENTS OF LANTERN AND LENSES
FOR THE ELECTRIC AND OIL LIGHTS.
t * 3SOA»LE- * < r
EUROPEAN LIGHT-HOUSE SYSTEMS. 249
I had no opportunity of visiting any of the light- ships Notes on the
belonging to the French service. These are ten in number, ship service. °
one of which carries a revolving red light. Most of them
are on the southwest coast of France. I have learned, how-
ever, the following particulars in regard to the regulations,
A light-ship's crew consists of a captain, mate, boatswain, oew.
(maitre $ equipage,} and seamen. They are under the orders
of the engineers or such superintendents as they may be as-
signed to. None can enter this service but regular sailors,
who have had at least three years' service in the navy, and
who know how to read and write.
Appointments are made by the prefect on nomination of Appointments.
the engiueer-in-chief.
The salaries are fixed by the 'Ministry of Public Works, Salarie8
and are subject to a deduction of 3 per cent., which is ap-
plied to the marine-hospital fund.
The captain is responsible for the service of the light, and Duties ot tim
has, on board ship, all the rights of captain of the merchant- capta
marine. He keeps the log and all the correspondence. In
his absence his place is taken by the mate.
The boatswain sees that the captain's orders are executed, of the boat-
and he is particularly charged with the order and cleanli- 8wam>
ness of the vessel. He is not required to assist in the man-
ual labor of cleaning the vessel, but he directs the details
of the work and keeps watch like the seamen only in excep-
tional cases to be judged of by the engineers. In case of ab-
sence his place is supplied by a sailor selected by the cap-
tain.
The captain and mate have alternately fifteen days of services of cap-
service and fifteen days ashore $ the sailors pass alternately of Sew!1*'
a month afloat and fifteen days ashore. These leaves are,
on some vessels, reduced one-half during the bad season.
While ashore the officers and sailors are at the disposal under orders
of the engineer-in-chief, and cannot quit their places of resi- ashorl!ne€
dence without authority. They are obliged to obey any
orders that may be given them, either to return aboard, to
attend to embarkations, or to any of the lights or beacons
of the department.
The captain is responsible for the provisions, and keeps
the account of them. He may detail a seaman for 'cook, or
decide that all shall take their turn.
THE INTERNATIONAL EXHIBITION AT VIENNA,
1873.
From Paris I proceeded to Vienna by way of Ulm, Augs-
burg, and Munich. I intended to have gone via Venice, and
250 EUROPEAN LIGHT-HOUSE SYSTEMS.
Trieste, but when I arrived at the foot of the Saint Gothard
Pass, exaggerated accounts of the cholera prevailing at the
former place, deterred me from taking that route.
On arriving at Vienna and presenting myself at the lega-
tion of the United States, I was received in the most cordial
manner by the Hon. Mr. Jay, the American Minister, who
proffered every assistance in his power.
Buildings. The exhibition buildings were on a grand scale, and. it
was said the Austrian government had already expended
on this exhibition more than 20,000,000 gulden, or more
than $10,000,000.
Most of the departments, particularly the department of
machinery, were well filled $ and the same may be said of
the spaces allotted to the different countries, with a few
exceptions, which include, I regret to say, that assigned to
the United States. From some cause, probably our re-
moteness from Vienna, the American exhibition was ex-
tremely meager.
hiwtione%°rtah5 * was disappointed at the small number of articles of
houses°and?iavi "" Merest pertaining to light-houses and other aids to naviga-
gaticn. tjon. and those which were exhibited were mainly sent by
the French and Austrian governments and the lens makers
of Paris.
Display by the The "Department of Public Works" of France had a
of Public fine display of models and drawings of light-houses in con-
nection with an extensive exhibition of views and models
of other works of the Corps des Fonts et Chaussees. I did
not observe anything particularly novel in the construction
of the light-houses, but they all showed evidences of the
good taste in architecture which characterize all works of
the French engineers.
Light-houses The following is a list of the light-houses represented:
represented.
Phare de la Palmyre, a wrought-iron range or leading
light-house on a screw-pile foundation.
Phare de Royan, a masonry range or leading light built
in alternate courses of stone and brick, the upper portion
of the tower being of a peculiar shape, for the purpose, most
likely, of serving as a day-mark.
Phare des Roches-Douvres, a wrought (plate) iron coast-
light, very much like the Phare de la Nouvelle Calcdonie,
shown in M. Keynaud's U Eclairage des Cotes de France.
Phare du Four, a k< rock" light-house.
Phare cPAr-men, a coast-light of stone masonry— a rock-
station.
Submarine The Corps des Ponts et Chaussees had also models of sub-
foundations. marine foun(iations for harbor light houses built on shoals
SUBMARINE CONCRETE FOUNDATION
FOR
A HARBOR LIGHTHOUSE. PLATEXLVII.
EUROPEAN LIGHT-HOUSE SYSTEMS. 251
or bars, very much like those which I had designed for our
lights in Long Island Sound, Delaware Bay, Chesapeake
Bay. and other localities where light-houses are subject to
injury from ice.
Two methods were represented, in one of which the iron
tube or shell is left in place after it is filled with concrete;
the other showed a cylindrical foundation of concrete made
by means of a movable mould, which is turned around an
axis, as represented by Plate XL VII.
Several novelties were shown by the lens-manufacturers
of Paris.
M. Lepaute exhibited a third-order revolving lens, a Lens exhibited
duplicate of the one which I have described as exhibited to
me at his manufactory at Paris, in which one-half showed a
fixed light and the other half was divided into eight con-
secutive flash- panels.
This would be a striking characteristic in waters where
there are already many lights, and where in placing a new
one it becomes necessary to distinguish it, particularly if
the flash panels were covered with red screens, which would
tend to equalize the range of the fixed light and the flashes.
This lens was furnished with a mechanical or pump lamp,
with a three-wick burner of the kind recently adopted by
the French, which is adapted to the use of either colza or
mineral oil, though the latter is designed to be used in it.
The clock-work operating the pumps was specially de- re^^nw^rk for
signed for revolving lights by M. Lepaute, and was remark-
able for the small space required for it, viz, not more than
six inches in diameter, a great improvement for small orders
of lights.
Sautter, Lemounier & Co. exhibited photographs of the
flame from the Farquhar burner, (the patent-right of which
is owned by this firm,) and the following lenticular ap-
paratus :
1st. A range light or feu de direction, showing alternately Eange-iigkt by
red and green. This apparatus was composed of a dioptric nSr*6!' ""
and catadioptric lens for fixed light, embracing 150°, a cata- "
dioptric reflector placed in the dead angle, and two groups
of vertical prisms arranged in front of the apparatus for
fixed light, in the space on either side of the axis and out-
side the angle which it is required to light. These elements
are so calculated that they concentrate the light from the
fixed-light lens and distribute it as uniformly as possible
throughout an angle of 45°. Between the fixed-light ap-
paratus and the vertical prisms there is a circular screen,
composed of three plates of glass,' each embracing 75°.
252 EUROPEAN LIGHT-HOUSE SYSTEMS.
Red and^ green, The two outer plates are red, the middle one green. The
frame-work supporting this screen receives an intermittent
oscillating movement, so that the light changes rapidly
from one color to the other, preserving a constant color for
a determinate time.
The screen passes through an arc of 75° in four seconds ;
then it is at rest for sixteen seconds, and then repeats the
motion in an opposite direction, and again becomes motion-
less. This movement brings successively before each part
of the apparatus first the red and then the green panes, so
as to produce the characteristic required.
pier- light by 2d. A pier-light, (fanal de jettee.) This light presents a
very characteristic appearance, and if placed near a town
it would never be confounded with ordinary street and
house lights. The apparatus is composed of an ordinary
fourth-order lens for fixed light, around which revolves a
drum composed of vertical plauo-cylindric lenses, each of
which receives a luminous beam 18° wide, and concentrates
it within 6°, thus diminishing the divergence and augment-
audnunfla8iifespro ing the intensity in proportion of 1 to 3. This drum
reaches to just above the central lens of the apparatus, so
that all the upper prisms preserve the appearance of a fixed
light of sufficient intensity to be seen at least twelve miles.
On account of the interposition and regular revolution of
the movable lenses, the light presents a series of dilatations
like equidistant pulsations, which gives it a very character-
istic appearance. Experiments made to determine the best
interval between two pulsations showed that it ought not
to be less than a second and a half, for if the flashes were
nearer together they might be confounded with the natural
scintillation which lights near water have, under certain
atmospheric conditions.
The lens exhibited was of the fourth order, but fifth and
sixth order lenses of the same kind can be easily con-
structed.
le^for^eiSc 3<*' A ver^ fine scintillating lens for electric light, for the
light, following description of whieh I am indebted to the courtesy
of Messrs. Sautter, Lemonnier & Co.:
u In most of the apparatus for electric light hitherto con-
structed, the optical part is composed of a cylindrical lens
for fixed light 30 centimeters in interior diameter, before
which, in flashing lenses, prisms of vertical elements are made
to pass. We prefer to increase the diameter of the lens,
and that for several reasons.
8 Same ' u 1st. In case there should be used a more intense elec-
tor of the lens. trie light than the one produced by the machines now em-
ployed, (such a one, for instance, as is given by the new ma-
EUROPEAN LIGHT-HOUSE SYSTEMS. 253
chines of Gramme,) it would become necessary for the pres-
ervation of the glass that it should be farther removed from
the luminous focus.
" 2d. Because a larger apparatus is easier to keep in
order.
" 3d. Because the larger the apparatus the less the inevi-
table variations in the position of the luminous point will
affect the direction of the rays emerging from the lens.
"The apparatus (shown in Plate XL VIII) is composed of ^en
a cylindrical lens for fixed light, 75 centimeters in interior
diameter, with upper and lower catadioptric zones. The
metal supports of the central part are diagonal, so that in
no direction does the frame completely obstruct the light.
"A polygonal drum, composed of twenty-four vertical piano-
cylindric lenses, envelops the apparatus from the top down
to just below the central lens, and is made to revolve
regularly, by means of clock-work placed in the pedes-
tal of the apparatus. Each lens receives a luminous beam
15° wide, and concentrates it within 5°. In the apparatus
which was exhibited, the drum makes a complete revolution
in 120 seconds, so that the flashes succeed each other every
five seconds. The duration of the flash is half the interval
between the flashes, and the fixed light of less intensity is
constantly visible. The intensity of the former is about
eight times as great as the latter. The proportions remain
the same whatever may be the intervals between the flashes ;
if the interval is increased the absolute duration of the flash
is increased in the same proportion.
" In oil-lights a remedy is sought for the short duration
of the flashes by increasing the diameter of the flame. This
disadvantage will not exist in electric lights arranged as we
have described, the divergence being caused not by the di-
ameter of the luminous focus, but by the form of the lens,
and existing only in the horizontal plane— that is, without
loss of light.
" The electric lamp constructed by M. Serrin is placed on
a revolving plate, eccentric with regard to the platform of
the apparatus-. This plate can receive two lamps back to
back. It has two rails on which the lamps slide, and which
are prolonged on a platform attached to that of the appa-
ratus, and jutting out behind. The plate can be held by a
spring-catch in two positions diametrically opposite. In the
first of these positions, one of the lamps is at the focus of
the apparatus, and the other in position to be attended to
and its carbons changed. In the second position the reverse
takes place. The current passes and the lamp is lighted of
itself when placed in position.
254
EUROPEAN LIGHT-HOUSE SYSTEMS.
" This apparatus should be placed in a lantern having
flat steel diagonal sash-bars with an inclination correspond-
ing to that of the lens-frame."
Besides the optical apparatus exhibited by Messrs. Saut-
ter, Lemonnier & Co., they displayed an iron light-house
tower of peculiar construction and excellent workmanship.
Translation of The following description of it, is translated from the
Ir on light
house tower.
description. a
" Annales Industrielles » of September 28, 1873 :
Formation
tower.
" The tower shown in elevation, (Fig. 1, Plate XLIX,) rests
on a foundation formed of eight radiating iron ribs bound
together by masonry, and rising about 5 meters above the
terrace on which the structure rests. It is composed of a
sheet-iron cylinder 12m.50 high, with a winding stairway
inside, and strengthened by eight buttresses or ribs of iron.
These buttresses take the form of brackets above and sup-
port a cast-iron gallery which extends around the lantern.
of " The cylinder or central tower is formed of five sheet-
iron sections Om.006 thick, each 2m.50 high and lm.80 in
diameter. The interior of each is occupied by twelve steps
of corrugated sheet-iron, the upper part of which forms a
landing ; riveted corner-pieces hold them against the outer
envelope, and a cylinder Om.40 in diameter supports them
at the center. The sections fit into each other and are held
together by rivets. Each weighs 1,500 kilograms. The
vertical ribs are each formed of four pieces, one above the
ol her, and they are bound together by three bands or rigid
horizontal crowns placed at equal vertical distances.
u The tower is mounted without exterior scaffolding by
means of a gallows-crane supported on the last section put
in place. It is shown in detail in Fig. 4. It is composed
of an upright formed of two T-irons connected by tie-pieces
and held at the lower end by a cast-iron pivot. The arm,
formed of two flat pieces of iron connected by braces, carries
two pulley-blocks and a hook intended to receive a tackle.
The fall of this tackle is conducted from the pulley-blocks to
the upright axis of the crane. It descends vertically in this
axis, traverses the pivot, and a final pulley 'carries it to a
windlass used for hoisting.
Placing the first " It was first necessary to place the first section on the
section." foundation, an operation which was somewhat difficult, as
the space for maneuvering was small. In order to effect
it the crane was used, it being set up on the foundation and
supported by guys. Eaised to the required height the sec-
tion was brought into place by rotating the crane. This
first operation would in general practice offer no difficulty,
Crane.
Crt
n
5
30
o
EUROPEAN LIGHT-HOUSE SYSTEMS.
255
Tools.
and could be done, according to circumstances, by any other
means than that we have just described. But when this
section is once placed and solidly bolted to the foundation,
the mounting should continue and be finished without the
aid of any scaffolding or support taken outside of the tower
itself. The mounting comprises, first, the placing of the Mounting.
iron tube or the superposition of the sections of which it is
composed, and which, as we have said, weigh about 1,500
kilograms each ; second, the placing of the ribs, rings,
brackets, galleries forming the frame-work, and the crown-
ing of the structure with the lantern and apparatus. These
latter pieces are relatively light, and can be raised to place
"by means of falls attached to the upper part of the central
tube. If the tower is not very high the most sinlple mode
of mounting consists in first superposing all the sections,
and then fitting the ribs and other pieces of the frame-
work. When the tower is high it is prudent to carry on at
the same time the mounting of the tube and the placing of
the ribSv.which strengthen it.
"The tools employed are:
" The crane above described, with an extra pulley and a
windlass on the ground ;
u A movable scaffold shown in Fig. 5 5
" Falls and cordage.
" The successive operations are :
"Baising and putting in place the sections 5
u Bolting the sections together;
"Baising the crane after the placing of each section;
" Lowering and raising the movable scaffold for each
section placed; that is to say, once before to raise the
crane and put it in position, and once after to bolt the sec-
tions together.
" The placing of the ribs, the rings, the upper gallery,
and finally the lantern and illuminating-apparatus.
" We have already described the crane and the way it is
used to mount the first section. It is used similarly to
mount the other sections, with this difference: that instead
of placing it on the foundation, it is set, by means of cast-
iron supports, on the last section placed. The bolting of
the sections is done by means of the movable scaffold at-
tached to pulleys suspended from the summit of the tube
already mounted. The raising of the crane is shown in
Fig. 3, and is effected as follows : Two falls are attached to
the top of the section and each side of the foot of the crane,
to hooks made for the purpose. The support c is unbolted,
it is remounted and fixed to the top of the last section; at
Operations.
Raising t h o
crane.
256 EUROPEAN LIGHT-HOUSE SYSTEMS.
the bottom of the saihe section is placed the guide-support
d, which obliges the crane to ascend vertically. Finally,
when it is raised as far as desired, the support of the pivot
/is bolted and the operation terminated.
scaffold. uThe lowering and raising of the scaffold is done by
hand, by men placed on the scaffold itself. The raising of
the ribs and all the other parts of the central tube is done
by hand with pulleys. The putting of them in place and
the bolting or riveting of them is done by means of the
movable scaffold. For all these operations six men are
quite sufficient, and no greater number was employed at
Vienna during the entire mounting.
''The ease and economy of mounting, is not the sole
advantage of the system of constructing iron towers adopted
by Messrs. Sautter, Lemonnier & Co., and applied by them
to towers of all dimensions. But in this article we have
only wished to call attention to the interesting fact that an
edifice of great height can be rapidly, surely, and inexpen-
sively set up by a very few men, and without the aid of
scaffolding."
Lenf.-arpnrr.tuB Barbier & Fenestre had on exhibition the following lens-
cxhibitedbyBar- „
lier & Fenestre. apparatus :
A third-order apparatus flashing 30" — 30", with hydraulic
Funck lamps.
A fourth- order flashing apparatus, with Doty lamps and
a new mechanical arrangement.
A fifth-order apparatus F. V. F., 2'— 2', 180°.
A sixth-order range-light, with two prisms so arranged
as to permit of an accurate adjustment of the direction in
which the light is thrown.
They had also a Doty four-wiok lamp with a clock-work
pump.
_ Models of swed- The Swedish exhibition contained two models of iron
light-houses resembling ours on the Florida reefs. Instead,
however, of the socket-joints which we have used, the col-
umns are connected together by means of -flanges and bolts.
Between the flanges are placed stout wrought-iron disks,
having projections to which are fastened the horizontal,
radial, and peripheral braces. The lugs or ears to which the
tie-rods were made fast were on the upper or lower side of
the flanges, as the strain was to be downward or upward;
in other words, the flanges took upon themselves the strains
upon those lugs.
These arrangements, which are shown in Figs. 28 and 29,
are, I think, improvements in the modes commonly in use
for similar structures.
EUROPEAN LIGHT-HOUSE SYSTEMS.
Iii Fig. 28, A A are two hollow cast-iron columns fas-
tened together by bolts through flanges; a, ear to which the
tie-rods 1) are secured; c, large link through which the
small link d is passed ; e, wrought-irou plate between
flanges.
Fig. 28.
257
Details of Swedish light-house. Elevation.
In Fig. 29, A is the column ; a «, ears for the attachment
of the tie-rods ; ///, radial and peripheral struts of rolled
iron fastened to wrought-iron plate e 6, which is held be-
tween the columns as shown in the elevation, Fig. 28.
29.
Details of Swedish light-house. Section.
In the Austrian part of the exhibition was a "Xebelhorn," Austrian
S. Ex. 54 17
258 EUROPEAN LIGHT-HOUSE SYSTEMS.
or fog-trumpet operated by steam ; of this, however, I could
learn but little except what was contained in tlie account
given in the official catalogue, of which the following is a
translation :
Translation of «« This apparatus has been constructed at Trieste, after
description.
the designs of G. Ainadi, engineer.
" In foggy weather it is impossible to bring to the notice
of mariners the threatening or desired proximity of land,
by means of light-houses or light-signals in general. It
therefore becomes necessary to carry sound far over the
sea by means of vigorous acoustic apparatus, and thus
to advise the mariner that he is approaching the coast.
Several kinds of apparatus constructed for experimental
purposes, and to which were applied the shrill notes of the
whistle, could not, just on account of the high pitch of the
sound, answer the purpose, and the sounds were lost at a
short distance from the coast.
uln this new fog-signal there are deep notes, formed like
those of an organ, by means of movable metallic reeds vi-
brated by steam, and they are sent out in a given direction
through a trumpet or augmentor of sound. This signal has
been heard, according to the experiments made, as far as
sixteen nautical miles.
"In this apparatus, (a similar one is in operation at
Trieste.) the notes are formed automatically by means of
a steam-engine at given intervals, and the apparatus is
turned at the same time on a vertical axis to reach all points
of the horizon in a uniform manner."
After my return to Paris, I wrote to the Hon. Mr. Jay,
and requested him to be good enough to procure, if tlie
Austrian government would be pleased to communicate the
information, drawings and descriptions of this fog- trumpet,
of a reflector which I had also observed in the Austrian
part of the exhibition, and of the Austrian buoys. A few
by the Austrian days ago I had the great pleasure of receiving from Mr.
8Dt' Jay, through the State Department, a package containing
the desired drawings and descriptions ; also copies of cor
respondence between himself and the Austrian Minister of
Foreign Affairs, in regard to my request, and of which the
following are copies and translations:
Letter of Hon. "THE AMERICAN LEGATION AT VIENNA,
Mr- Jay- "February 23, 1874.
" DEAR MAJOR ELLIOT : In acknowledging your note of
January 30, I am happy to be able to send you, as I do by
this post, through the State Department, a roll which I re-
ceived this morning from the Foreign Office.
EUROPEAN LIGHT-HOUSE SYSTEMS, 259
" I annex a translation of the note of the Count Andrassy
and a copy of my reply.
" You will see that the Ministry of Commerce is prepared
to appreciate the drawings and plans which you had pro-
posed to send, and which your note leads me to expect
presently. Should there be any others that you think would
be new and interesting to this government and which there
is no objection to communicating, I hope you will send them.
Not only the Foreign Office, but all the Ministers here, are
so obliging in furnishing promptly and gracefully all infor-
mation asked for, and extending facilities to our officers,
that I am always glad of an opportunity of reciprocating
their courtesies.
* * * * * # *
il I am, dear sir, faithfully yours,
"JOHN JAY.
" Major GEORGE H. ELLIOT,
11 Light- House Board, Washington."
[Translation.]
" The undersigned, Minister of the Imperial House and Translation oi
for Foreign Affairs, is only to-day enabled to place at the dis- trla^MiS^to
posal of Mr. John Jay, Envoy Extraordinary and Minister Hon< Mr' Jay'
Plenipotentiary of the United States of America, in compli-
ance with his esteemed notes of 20th August and 13th De-
cember last, the drawings and description transmitted by
the Imperial and Royal Ministry of Commerce.
" a. Of the fog-horn exhibited at Vienna in the year 1873 ;
" b. Of the parabolic reflector of Professor Osnaghi ex-
hibited on the same occasion ;
" c. Of the buoys in use upon the Austrian sea-coast.
" The Minister of Commerce, to whom the compliance with
the wish of the Envoy has afforded especial pleasure, has at
the same time requested the undersigned to plead with the
Envoy, as excuse for the delay in the transmission of these
drawings, the circumstance that the authorities at Trieste
who exhibited at the Vienna exhibition the objects in ques-
tion were able but recently to obtain a description of the
fog-horn.
" While the undersigned has the honor to communicate
to the Envoy the above fact, he begs further to state that
the Minister of Commerce would gratefully acknowledge the
courtesy should Major Elliot, in return for this collection,
place the Imperial and Royal Government in possession of
the promised drawings of those safety-signals which in the
United States are in use and have attained such high per-
fection.
260 EUROPEAN LIGHT-HOUSE SYSTEMS
" The undersigned avails himself of this occasion to renew
to the Envoy the assurance of his distinguished considera-
tion.
" Vienna, February 22, 1874.
" For the Minister for Foreign Affairs,
" ORCZY."
Mr.jly to ££ "The undersigned, Envoy Extraordinary and Minister
trian Minister, plenipotentiary of the United States of America, has the
honor to acknowledge the receipt this morning of the note
of his Excellency the Count Andrassy, Minister of the Impe-
rial House and for Foreign Affairs, dated February 22, accom-
panied by a sealed roll of drawings and descriptions trans-
mitted by the Imperial and Royal Minister of Commerce —
" a. Of the fog-horn exhibited at Vienna in the year 1873 ;
" b. Of the parabolic reflector of Professor Osuaghi, ex-
hibited on the same occasion ;
u c. Of the buoys in use upon the Austrian sea-coast ;
" These drawings are to-day transmitted to the Depart-
ment of State for Major Elliot, of the governmental Light-
House Board at Washington, and will probably reach that
office in time to be used in the preparation of his forthcom-
ing report.
" The undersigned begs to add in reference to His Excel-
lency's remark, that the Imperial and Eoyal Minister of
Commerce would gladly acknowledge the courtesy should
Major Elliot, in return for this collection, place the Imperial
and Royal Government in possession of the promised draw-
ings of the fog-signals which in the United States are in
use, and which, His Excellency is pleased to say, have attained
such high perfection, that the undersigned has received a
note from Major Elliot, dated the 30th of January, saying
that in a few days a parcel would be dispatched to this lega-
tion for the Imperial and Royal Ministry.
" The undersigned has the honor to present his thanks to
His Excellency, and, through His Excellency's obliging inter-
vention, to the Imperial and Royal Minister of Commerce, for
the valuable information now afforded upon a subject so
interesting and important to the commerce of the United
States, and for their courtesy in furnishing the same to this
legation immediately upon its transmission by the authori-
ties at Trieste.
« The undersigned embraces this opportunity to renew to
His Excellency the assurance of his distinguished considera-
tion.
"JOHN JAY.
" FEBRUARY 23, 1874.
" His Excellency the COUNT ANDR!SSY."
RSITTT
EUROPEAN LIGHT-HOUSE SYSTEMS. .261
Plate L, which is copied from the photograph sent me
by Mr. Jay, represents the fog-trumpet as I saw it at the
exhibition at Vienna, and the following is a translation from
the Italian of the description which accompanied it :
" Since the introduction of acoustic signals, used in Amadi's fog-
trumpet.
America as well as in Europe to mark dangerous points on
the coast in foggy weather, it has become desirable to have
a more perfect instrument, an apparatus that can be used
not only at light-stations in foggy weather and snow-storms,
but also on board of ships, especially on steamers, riot only
as an alarm but as a signal for correspondence.
" This object has been fully accomplished by the inven-
tion of Giovanni Amadi, of the Technical Institute of Trieste.
His trumpet was exhibited at the universal exposition at
Vienna, and was awarded a medal of merit.
" This apparatus, which consists of a trumpet, formerly Description.
operated by compressed air, but now directly by steam, is
provided with aa automatic distributing steam-valve, and
with a special valve with finger-board (operating keys) so as
to produce sounds at will.
" The instrument has a most extraordinary power in pro- Power,
portion to its dimensions and to the pressure of steam re-
quired to produce the vibrations ; it can be put up either
directly over the boiler or separately, and connected with
it by a pipe, and it can be turned to any part of the horizon.
" In addition to its use as a fog-signal on shore, it may be
applied on board of steamers of whatever steam-power, and
is especially advantageous on board of men-of-war.
u By means of the finger-board, one is enabled to give long Use of finger-
and short sounds at will with great accuracy, and commu-
nications may be made at night, in fog, or in snow-storms,
by means of an alphabetic formula similar to that used in
telegraphy.
il The trumpet (shown in Plate L) is operated by a steam- steam-pi,
boiler of eight horse-power and a pressure of twenty-five re
pounds per square inch.
" The boiler is more than sufficient to produce thirty blasts Boiler.
in thirty seconds, which are audible at a distance of fifteen
nautical miles in clear weather.
" Connected with the boiler is a small machine, which d^1
operates the automatic distributing steam- valve and can be ivo sounds
so regulated that the different intervals in the sounds dis-
tinguish the different stations where trumpets are used.
" In the Technical Institute at Trieste, where this trumpet
was constructed, it was very particularly tested, and the
government officers at Trieste testified that the sounds were
262
EUROPEAN LIGHT-HOUSE SYSTEMS.
fifteen1 miieseard pl^ty audible at a distance of fifteen miles, the height of
the trumpet being thirty English feet above the sea ; also
that when operated with the finger-board, the signals, accord-
ing to Morse's method, could be plainly distinguished at a
distance of six nautical miles.
Trumpet placed
on Point Saivore, "The Austrian government purchased this trumpet to
operate it on Point Saivore, Istria, after trial of a smaller
one of the same kind (audible five miles) near the light-
house at Trieste.
"A third trumpet, with a steam-generator of two horse-
power, and audible eight miles, has also been ordered and
finished, and will be put in operation on board of the light-
ship anchored at Grado."
The following is a translation from the German of the
description of the reflectors before referred to, and, with the
sketch as reproduced in Fig. 30, illustrates clearly its prin-
ciples :
Fig. 30.
to be
light-
ship at Grado.
Osnaghi's reflector.
"PARABOLIC REFLECTOR FOR INTERMITTENT LIGHTS,
DEVISED BY PROFESSOR FERDINAND OSNAGHI.
a)°aratus°f the u ^he principal object in devising this apparatus is to
collect as many rays of light as possible into a beam paral-
lel to the axis of the reflector, thus obtaining the greatest
possible amount of light at the points illuminated by the
beam, and by making the best use of all the light produced
in one direction avoid the considerable loss which occurs in
most apparatus of this kind.
ieuslan° " c°nvex u lst- Tne ra^s are united iu a beam by means of a
plano-convex lens placed in front of the luminous focus.
^spherical mir- u 2d. A spherical mirror is inserted at the vertex of the
parabolic surface.
"According to the laws of reflection from curved surfaces,
if a luminous body be placed at the focus of a parabolic
EUROPEAN LIGHT-HOUSE SYSTEMS. 263
reflector, the rays will be reflected parallel to the axis, but
the cone of rays tangent to the circular riin, and all rays
within this cone, will radiate divergently and be scattered.
To bend these rays parallel to the optical axis the piano- Use of i>i.um
convex lens.
convex lens is used.
u If the vertex of the parabolic reflector were retained
the rays of light which, directly behind the lens, are reu- flector without
dered parallel by reflection, would, on passing through the
lens, be concentrated into its focus and thence proceed di-
vergently, so that nothing would be gained ; but if we
remove the parabolic vertex and substitute a spherical mir-
ror with the luminous focus for its center, the rays will be
reflected directly back through the focus, strike the lens at
the same angle as if they had come directly from the source
of light, and after refraction proceed parallel to the optical
axis. In this way all the rays are united in a luminous
beam of parallel rays of great intensity, and the loss of
light is reduced to a minimum.
" Some loss occurs on account of the apertures in the L..*.S <>r ii-i,t.
parabolic surface, through which enter either the carbon
points of the electric lamp or the burners of ordinary oil or
petroleum lamp, and furthermore from the absorption
which always occurs when light is reflected from metallic
surfaces. Although there is more absorption by reflection
than by refraction, it may be asserted that this apparatus
would have an advantage over the dioptric Fresnel lenses
now in use. for the reason that it concentrates the entire
light into one beam, while with dioptric apparatus the rays
are collected into from eight to twelve divergent beams,
each of which gives only an^ eighth or twelfth of the total
light transmitted.
u Flash-lights which appear with full intensity at certain ^ Use in flash
intervals and then disappear require a rotation of the opti-
cal apparatus. In the Fresnel system where there are sev-
eral flash-panels the motion may be slow, for to produce one
flash per minute the revolution takes place only once in
eight minutes if there are eight panels. The new appara-
tus, however, must make a revolution in one minute if it is
required to show a flash every minute. This accelerated
motion can easily be obtained, but, as the apparatus is light,
finer and more accurate clock-work is required.
" The principal dimensions of this apparatus when adapt- Dimensions ..i
the reflector for
ed tor electric light are as follows : use in electric
" Focal distance of the paraboloid, 30 millimeters.
" Opening distance of the paraboloid, 375 millimeters.
" Diameter of the spherical mirror, 85 millimeters.
264 EUROPEAN LIGHT-HOUSE SYSTEMS.
"Diameter of the plano-convex lens, 85 millimeters.
"Focal distance plano-convex lens, 45 millimeters.
" Height of axis of paraboloid above the bottom plate,
280 millimeters.
" In the vertical plane the paraboloid can be moved around
a horizontal axis passing through the focus, and in the hori-
zontal plane it may be rotated with its standards around a
vertical pivot. When ordinary lamps are used the dimen-
sions should be increased to correspond with the size of the
luminous body. Notwithstanding the small size of the ap-
paratus, it has given very good results with a petroleum -
lamp, quite surpassing a fourth-order Fresnel apparatus.
etfSeV1 lisllt i; Photometric tests showed that with a paraffiue-candle
at the focus of the reflector the co-efficient of concentration
is 21,000, that is, 21,000 such caudles would be required to
produce the illumination of a plane surface that one would
give at the focus of the reflector.*
use of reflector " To use this apparatus for fixed lights, the rays, already
for fixed lights.
concentrated in one parallel beam, must be converted into
a luminous disk by a second reflection. A considerable part
of the original intensity will, however, be lost by spreading
the rays around the entire horizon. To effect this the para-
bolic reflector is placed in a vertical position with the mouth
or opening upward, and the rays from it are received by a
set of totally reflecting prismatic rings arranged conically.
The loss of light by reflection will be but trifling.
cost. " Nothing can be positively stated as to the cost of the
reflector, but it is certain that even a large one would not be
as expensive as a dioptric apparatus."
Professor Osnaghi's combination of catoptric and dioptric
agents is not new, having been previously invented by Mr.
Thomas Stevenson under the name of " catadioptric holo-
photal reflector,"! and has been used in many cases in Great
Britain.
In Fig. 31 will be found what I conceive to be an illustra-
tion of the professor's ideas in regard to a fixed-light apparatus.
In this figure a is the focus ; &, the spherical mirror j c, the
plano-convex lens ; d d', the £>arabolic reflector ; e e e, the
totally reflecting prisms ; pp, the carbon pencils for the elec-
tric light. It will be observed that the major part of
the light proceeding from the focus a of the parabolic re-
flector impinges against and is reflected by the surface
of the latter; that the remainder of the rays are caught
and refracted by the plano-convex lens c ; that both the
* This co-efficient is excessive, and is, without doubt, an error. — G. H. E.
t See Light-house Illumination ; Thomas Stevenson, 1871.
EUROPEAN LIGHT-HOUSE SYSTEMS.
reflected and refracted rays are bent into a vertical beam
which impinges against the conical surface of total reflec-
265
. 31.
Reflector as adapted for a fixed light illuminating 360°.
tion formed by the prisms e e e, &c., and that from this sur-
face the rays are uniformly distributed around the horizon.
In this apparatus for fixed light a considerable loss of light LOSS of I^M.
would occur —
1st. In the reflection of the rays by the parabolic reflector
and the refraction by the piano-con vex lens;
2d. In the passage of the rays from the bottoms of the
totally reflecting prisms to the surfaces of total reflection,
and thence to tho vertical sides of the prisms.
I should judge this apparatus to? fixed light inferior co
the dioptric apparatus of Fresnel, in which but a single
agent is used.
The Austrian government had also on exhibition some
bell, mooring, and other kinds of buoys, drawings of which
accompanied the drawings and descriptions of the fog-
trumpet and reflector received through Mr. Jay; but I
observed nothing else of sufficient importance to take ac-
count of in this report.
The drawings and other information concerning our light- Drawings tor
house establishment, referred to by Mr. Jay in his letter to Austria, -<,v<>rn
me of February 23, were some weeks ago forwarded to him m<
by the board, through the State Department, for presenta-
tion to the Ministry of Public Works of Austria.
26 G EUROPEAN LIGHT-HOUSE SYSTEMS.
Diploma taken I should not forget to mention' that the photographs and
by American pic- . ,. „ „ ,. . . .
tures of light- paintings of some of our light-houses occupied a prominent
place in the American part of the exhibition, and it has
been announced that they were awarded a diploma of honor.
^ Kindness of Mr. i cannot close my account of the exhibition at Vienna with-
out expressing my warmest thanks to the Hon. Mr.
Jay, the American minister, for his great kindness to me at
Vienna and since my return, as well as for the interest he
has shown in furthering the object of my visit, particu-
larly by his successful efforts to procure for me from the
Austrian government, for publication in this report, draw-
ings and descriptions of some of the aids to navigation
which that government had on exhibition.
RETURN VOYAGE.
I sailed from Liverpool in the Cuuarcl steamship Cuba on
the 30th of August, after an absence of four months from the
United States.
Couversati on On mv return vovage to America I had several couversa-
Avith Captain
Moodie. tions with Captain Moodie, one of the oldest and most ex-
perienced commanders of the Cunard line, respecting the
light-houses of Great Britain and the United States, and an
interesting fact was mentioned by him in regard to one of
the gas light-houses on the Irish coast, viz : that on the
night in which we came out of Saint George's Channel,
the weather being thick, he observed the light on Tuskar
gas-Sight! B Rock at a distance, as he supposed, of six miles, judg-
ing by his former experience with this light, but when
he had come up to it he found he had run more than twelve
miles after he first observed it. He subsequently found
(probably when we stopped at Queenstown for the mails)
that since his last voyage the light had been changed from
oil to gas, and he remarked that he was confident he saw
the gas-light at least twice as far as he would have ob-
served the oil-light in the same condition of the atmosphere.
So55?stack at •"• agked him u*s experience and opinion in regard to the
low fog or " occasional ?? light at South Stack, on the coast
of Wales, which I have described, and he stated he had
found it of much value when not a ray could be seen of the
upper light, which is often obscured in fog.
Aidstonaviga- Captain Moodie thought our lights efficient as far as he
tioii neatf New
York. had observed them, and spoke particularly of the great
value of the revolving light at Fire Island, on the outer
coast of Long Island, which is the first light ordinarily made
by over-sea steamers approaching New York, but he is of the
opinion that our aids for using Gedney's Channel into the
EUROPEAN LIGHT-HOUSE SYSTEMS. 267
harbor, (which he says -cannot now be used in the night-
time, particularly in thick weather) are insufficient, and
suggests that a light-ship should be moored where the fair-
way buoy is, inside the bar ; that the fair-way buoy outside
the bar should be replaced by a bell-buoy, and that the
present light-ship should be moored north-northwest from
her present position and into line with the bell-buoy and the
light-ship inside the bar.
Captain Moodie mentioned the difficulties of entering the Buoyage of
harbor of New York in the winter-time when the iron buoy 8 York.
are removed and spar-buoys are substituted for them, stat-
ing that in harbors much farther to the northward no diffi-
culty is found in maintaining the larger buoys in position
in winter;* also the difficulty in making out the positions of
the leading or range light-houses in the day-time when snow
is upon the ground, and suggested that they be painted
some dark color instead of white, to better serve as day-
marks, a change which has been effected since my return.
Captain Hoodie's views as to the desired ameliorations
in the system of aids to navigation at the entrance to the
harbor of New York are entitled to much weight, and the
investigation of the subject which I have made since my
return, confirms me in the opinion that the changes sug-
gested should be made without delay.
CONCLUSION.
In concluding my notes of inspection of European light-
house establishments, I will call the attention of the Board to x
those points which I think are of especial importance in the
foregoing report, and which I commend to its most careful
consideration :
(a.) As the subject of first importance, I will mention the superiority of
superiority of the English and French light-house lamps g
over our own. it will have been observed that while the
power of our light-house lamps is fixed, (i. e., they give only
the same amount of light in foggy and thick weather as in
fair, in the long twilights of summer as in the darkness of
the night.) the English oil-lamps are flexible in power, and
can be varied by the keepers to suit the varying conditions
of the atmosphere ; that the first-order sea-coast lights of
England may be raised from an equivalept of 342 (their
minimum) to 722 candles, while the maximum power of our
first-order sea-coast light is uniformly the equivalent of only
* I do not think this would be possible in the harbor of New York
without great loss. The ice-fields, moving with great velocity in the
spring, carry off any buoys which may be placed, and spar-buoys, which
are inexpensive, are, for this reason, used in winter.
268 EUROPEAN LIGHT-HOUSE SYSTEMS.
210 candles ; that while the English and French lights have
. been in recent years increased iu power, the actual consump-
tion of oil per unit of light has been decreased by improve-
ments in the supply of oxygen to the flame ; and that, if the
modifications which I have described in detail should be
adopted, we should increase the illuminating power of our
light-houses more than 50 per cent., which would be of in-
calculable benefit to commerce, particularly in ;' thick "
weather.
use of mineral- (ft.) The European governments, after careful and pro-
tracted experiments, are rapidly adopting the use of mineral-
oil instead of the vegetable and animal oils formerly used.
France has been the first to order the burning of the new
illuminant on all of its coasts, and the light-house lamps of
nearly all other nations of Europe, (including Great Britain,)
the nations of the East, and of South America, indeed all
that I could hear of except our own, are being changed for
its use.
Mineral-oil is more cleanly than the lard-oil consumed in
our light-houses; it is not injuriously affected by the
severest cold; the lamps are more readily lighted, and
do not require to be trimmed during the longest nights,
thus making commerce less dependent on the watchfulness
of the keepers ; while its cost is but little more than one-
third the cost of the latter.
The use of mineral-oil in the multiple- wick lamps used in
light-houses was not possible until the introduction of the
' double outer current of air to the flame, and the invention
of the mineral-oil light-house lamp, (to whomsoever it
belongs, whether to Douglass, Lepaute, or J)oty,) has pro-
duced, without doubt, the greatest improvement in light-
house illumination since the invention of the Fresnel lens.
There can be no doubt that the adoption of this oil by the
United States for use in our light-houses would stimulate
our refiners to produce an article which would fill the re-
quirements which I have mentioned in this report ; but if
they cannot, or will not, we can, as I have observed, import
precisely the same excellent kind of mineral-oil (Scotch)
which is now used in the light-houses of France and Great
Britain, and save more than fifty thousand dollars per an-
num, besides producing more reliable lights than we now
have.
housfisadmmi8- (c>) Jt wil1 nave attracted attention that, as in our service,
tration simpler the light-house establishments of Europe are under those
and more econ-
omical than our departments of government which correspond to our Treas-
ury Department ; also that there the administration on the
EUROPEAN LIGHT-HOUSE SYSTEMS. 269
sea-coasts is much more simple and economical than our
own, and that while in our service the law provides that
there shall be two officers in each of our twelve light-house
districts, in Great Britain and France there is but one offi-
cer for each district; that the officer whose duty it is to con-
struct and keep the light-houses and the lenticular and
other parts of the illuminating apparatus in repair and to
instruct the keepers in the use of the latter, is also the one
to inspect the light-houses. Were the salaries of these offi-
cers the only consideration, it would not be a matter of much
moment, but the dual arrangement in use in our service
since 1852, involves double sets of clerks, double expendi-
tures for rent of offices, fuel, and other contingent items,
for the service of the districts, which require an annual out-
lay of many thousands of dollars, while the service can,
there is no doubt,, be conducted with more efficiency and
economy * than now, by a single officer in each district.
This would correspond to the practice of France, which Administration
1 ' of French lights.
was the first to adopt a thorough and scientific light-house
system, and which is surpassed by no other country in the
science, simplicity, economy, and efficiency of its adminis-
tration. The entire management of the French lights (except
as regards the appointment of the keepers, which is in the
hands of the prefects or civil officers of the districts) is in
the officers of engineers, (des ponts et cliaussees,) who are
charged with the other works of river and harbor im-
provement; and while there are many other points in which
we are excelled in regard to the abov7e-named qualities of
good administration, it is hardly required of me that I call
attention to them here.
(il.) I would call attention to the desirability of modi- and
fying a few of those of our light-houses on which the
* From information derived from the excellent Memoire sur V ficlairage
des Cotes dc France by M. Reynaud, Inspector-General of the Engineer Corps
des Ponts et Chausse'es, and Chief of the French light-house establishment,
and from other sources, I find that the combined illuminating power of
the French lights, expressed in French units of light t, is 2199, and the
expense of the cost of maintenance is about $52.20 per unit per annum.
The total illuminating power of the light-houses of the United States
is 2233 units of light t, uud the cost of maintenance is $401.50 per unit per
annum, or about eight times the corresponding cost of the French
lights. In the calculations from which I have obtained these results, I
have not taken into account the cost of the erection of new light-houses,
the repairs of existing ones, the expenses of the few light-ships of either
service, nor the cost of the buoyage of the harbors.
t This is an aggregation of the powers of the naked flames ; that is, before con-
densation of the light by the lenticular apparatus.
270 EUROPEAN LIGHT-HOUSE SYSTEMS.
safety of life and treasure especially depends, for the in-
troduction of the electric and the gas-lights, w iich I
have described in great detail, since there are now many of
these lights in use in Europe, and I think we should not be
behind any nation in our efforts to lessen the dangers of the
coasts.
Kas'and ^lectSc ^ w^l have been observed that the uncondensed beams
n~ht- of each of these lights is equivalent to more than the com-
bined light of 2,000 caudles, while our maximum sea-coast
oil -lights are but little more than an equivalent for the light
of 200 candles. There is no light which can penetrate a
dense fog, but there is the multitude of intermediate con-
ditions of hazy and thick weather, between fair weather
on the one hand and dense fog on the other, which can be
illumined by such lights as that which I saw at Souter
Point, on the east coast of England, and which flashes over
the North Sea its condensed beams, each of which is more
than equivalent to the combined light of 800.000 candles !
^oost of chang- The cost of changing at a sea-coast light-house from oil
to either gas or electric light is not great, and it was stated,
as I have mentioned, that the cost of maintenance of the
gas-light, of which Professor Tyndall spoke so highly when
in the United States, is less than the cost of maintenance
of the oil-light.
of^cd and white («•) I should also mention the inequality which Professor
S?g ienseSrevolv' Tyndall, the scientific adviser of Trinity House, has estab-
lished between the red and white panels of revolving lenses
in the English light-houses, as mentioned under the heads
of " The Wolf " and " Flamborough Head " lights. In order
that the red may be seen at the same distance as the white
flashes, the English revolving and flashing lenses are now
made so that the areas of the red and white panels are in
the proportion of 21 to 9.
In the United States the red are of the same size as the
white panels in the same lenticular apparatus, and the result
is, that the white are seen at a much greater distance than
the red flashes ; so that when a red and white flashing light
first appears above the horizon it is liable to be mistaken
for a white flashing light on another part of the coast and
lead to disaster.
Ability to work (/'.) An improvement upon our service, to which I have
revolving lenses Ni/ '
by hand. called attention, is the ability of the keepers of a revolving
or flashing light to revolve the lens by hand if the ma-
chinery should become disabled.
(g.) I would especially mention the practice, of which I
saw many cases on the coast of England, of marking out
EUROPEAN LIGHT-HOUSE SYSTEMS. 271
dangers and important channels in the neighborhood of
light-houses by means of " red cuts." A marked instance
of the utility of the system will be found under the head of
Coquet Island.
(h.) The plan of utilizing the rear light of light-houses, or utilizing <>t
7 landward light.
that which would otherwise be thrown and wasted upon the
land, is mentioned at several places in the foregoing report,
and an application of the system by furnishing a low or occa-
sional light at our elevated stations on the Pacific coast, where
the lights at the summits of the towers are often obscured
in the fog-clouds, when it is clear below, has been suggested
under the head of Souter Point.
(i.) The rules of the European light-house establishments Light-keepers.
in regard to the appointment and promotion of keepers, on
whom the utility of light-houses and the safety of life and
property so largely depend, are fully described in the report,
and the facts are noted that for each light the number of
keepers is smaller than in our service ; that they are fur-
nished with circulating libraries ; that their pride in their
profession is stimulated by being furnished with a hand-
some uniform dress ; that they are promoted for merit ; that
they are educated with care for the management of lights
before they are intrusted with the charge of them ; that their
lives are insured for the benefit of their families, and that
they are pensioned when superannuated ; none of which ob-
tain in our own service.
(j.) The improvements suggested by Captain Moodie, of Aids to uaviga-
. , . . ' . tiou, New York
the Cunard Company, in regard to aids to navigation at the harbor,
entrance to the harbor of New York, deserve attention ; also
the fact of the insufficiency of fog-signals and lights on over-
s,ea steamers, which I have mentioned in the first part of
my report.
(k.) The maritime nations of Europe find no difficulty in the Revolving
use of revolving lights and efficient fog-signals on light-ships, iilnSs^
It is well known that a fixed is less powerful than a re- ships>
volving light, which more readily arrests the eye of the
mariner who is approaching the coast, and we have many
of them at our shore-stations, but we neither have revolving
lights nor fog-signals, except bells, on our light-ships.
It is an important fact to be noted, that of 43 light-ships
around the coast of Great Britain 30 of them have revolving
lights.
(1.) I would also call attention to the method of marking Buova,,e
buoys, and the importance which is attached in England to
frequently renewing the number and name of each buoy,
so that they shall always be distinctly visible ; to the prac-
272 EUROPEAN LIGHT-HOUSE SYSTEMS.
tice of making the size of the white checkers or stripes on
parti-colored buoys about 20 per cent, less than the black
or red, it being found that the characteristic distinctions of
the buoys are better preserved by this inequality, and also
to the plan of marking the different sides of channels by
buoys of different shape as well as color, so that they can be
more readily distinguished at night and in thick weather.
In my preliminary report I mentioned my obligations to
Mr. Pelz, chief draughtsman of the Board, and I cannot
close, without again tendering to him my sincere thanks for
his zeal and interest in preparing for publication the plans
and other drawings which I obtained in Europe ; also to Mr.
Baker, the talented financial clerk of the Board, for his excel-
lent translations of the French papers which are found herein,
and for his valuable assistance in the preparation of this
report for the press.
INDEX.
A CCIDENTS from use of mineral-oil, 194,
A 195, 198
— to electric light at La Here, 233
— provision against, at Grisnez, 225
Haisborough, 105
Howth Baily, 159, 162
— La Heve, 223, 225, 232
— Souter Point, 122
— South Foreland, 70
Wicklow Head, 161, 165
in gas-light apparatus, 162, 164
Acid, used for removing sea-weed, 147
Administration, light-house, foreign, supe-
rior to that of the United States, 268
Aids to navigation New York Harbor, 266,
271
Air, how admitted to English lanterns,
107, 154
at the Wolf, 143
Air-tubes, Douglass burner, 77, 82, 86, 151
— Doty burner, 74
— Farquhar burner, 206
— Fresnel burner, 208, 212
— Lepaute's 1845 burner, 209, 212
truncated-cone burner, 210. 212
modified Fresnel burner, 210, 212
Allard, M., 185, 193
drawings received from, 225
Allen, Mr. Robin, 19
Allowances to keepers, English service, 98
French service, 216
Scottish service, 177
Auiadi's fog-horn at Vienna, 261
American lights, opinion of Captain Mc-
Cauley, 15
— Moodie, 266
— burners compared with Douglass's, 88
Anchors for English light-ships, 93
buoys, 96
Anglesea, island of, visit to, 149
Apparatus, catoptric. See Reflector-ap_
paratus.
— dioptric. See Lenticular apparatus.
— revolving. See Machinery.
S. Ex. 54 18
Apparatus for electric light, 67, 123,221,
241
— gas-light, 75, 104, 159, 160, 161, 162,
165, 166, 167, 170, 171
testing oils, 188
— designs furnished by Commission des
Phares, 192
— prices fixed by Commission des Phares,
192
— at D6p6t des Phares, 186
Industrial Exhibition, Edinburgh, 180
Vienna Exposition, 251
Application de Vlmile mlncrale, < tc., by M.
Reynaud, 193
Appointments of keepers, English service,
98
French service, 216, 249
Scotch service, 177
boatmen, Scotch service, 178
Arago, observations on sound, 34
Areas best for red and white panels in
flashing lights, 118, 142, 270
Areometer, for testing oils, 188
Argyll, Duke of, cited, 55
Ar-men, phare de, model at Vienna, 250
Armstrong, Sir Wm., visit to his ordnance-
works, 120
Arnoux, M., 215
Arrow, Sir Fred., 18, 74
Atmosphere, eiFect of, on sound, 27. 29, 33,
38, 40, 41, 43, 44, 46, 49, 50, 51 , 52, 53, 55,
58, 59, 62
Austrian fog-horn, at Vienna, 257, 261
— government, drawings sent, 265
received from, 258
-D ALLYCOTTIN light, view of, 17
Barbier and Fcnestre, visit to manufactory
of, 206
agents for Doty burner, 207
their articles, exhibited at Vienna
Exposition, 256
Basin for rain-water in lantern-floor afc
Haisborough, 107
274
INDEX.
Beacons, clay, towers painted to serve as,
17, 108
on Wolf Rock, 141
French system of coloration, 186
— illumination of,' by gas, 172
— French service of, 217
Beazley, Mr. M., 147
Bell-boat off Queenstown. 17
Bell-buoy, mouth of the Mersey, 18
— Rundlestone, 144
Bell-buoys, English, 97
— French, 186
— Rundlestoue, 144
Bell Rock, light-dues at, 20
cost and contents of, 142
Bells, signal, La Heve, 233
Bilge-keel in English light-ships, 104
Bill of Port land lights, 135
Bishop light-house, cost and contents of,
142
Blackwall depot, visit to, 76
Board, United States Light-House, extract
from report of, 9
preliminary report to, 9
sent siren for English fog-
signal experiments, 36
— of Trade, English, controls British light-
house affairs, 21
— of Commissioners of Irish Lights, letter
from, 158
visit to, 158
Scottish Lights, visit to, 175
establishmenfc and organi-
zation, 178
Boat for landing, Wolf Rock, 143
Boatmen, appointment of, in Scottish serv-
ice, 178
Boilers, best for fog-signals, 25
for fog-signals at Vienna, 261
La Heve, 221
Seven Stones light-ship, 146
Souter Point, 126
South Foreland, 67
Bonus paid French keepers, 217
Books, at English stations, 108, 138
French stations, 220
— Scottish stations, 176, 177
Breakwater at Holyhead, 149
Plymouth, 137
Broglio, Due de, letter on French burners,
191
Bronze for window-frames, rock-stations,
143
Buoyage, English system, 96
— French system, 186
Buoyage of New York Harbor, 267
Buoys, Coquet, 127
— English. 95, 96, 102
— French, 186
— designation of, 96, 271
— for strong tide- ways, 95
channels, 95
— Godrevy, 148
— Herbert's, 95
— models at Vienna, 8
— Depot des Phares, 186
— moorings for, 96
— mouth of the Mersey, 18
— Queenstown, 17
— Rundlestone, 144
— water-ballasted, 95
Buoy-indicator, Yarmouth, 102
Buoy-list, English, 96
Buoy-shed, Blackwall, 97
— Yarmouth, 101
Bureau des Longitudes, experiments by, 34
Burner, Carcel, the French unit of light,
187, 196
Burners, comparative tables of old and
new systems, 87, 88, 201, 202, 211
— Doty's, 74, 181, 190, 191, 194, 203, 207, 209,
212, 256
— Douglass, for colza and mineral oils, 82,
83, 84, 86, 87, 104, 150, 169, 181, 190
gas, 79
— Farc[uhar,206,251
— Fresnel, for colza, 199, 208, 209, 212
gag, 199
— Lepaute's, of 1845, 205,209,212
truncated cone, 210, 212
modified Fresiiel, 191,203,210, 212, 215
gas, 215
paper on, 208
— foreign, are superior to those used in the
United States, 267
— means of varying oil-level in, 207, 212-
215
— received from Trinity House, 89
— results of improvements in, 20, 79, 84, 85,
86,88
— Silbe^s gas, 79
— six- wick, not used by the French, 189
— statement of French Minister, 191
— table of experiments with, 81, 82, 83, 84,
86, 168, 169/170
— Wigham's gas, 75, 104, 159, 160, 161-171
— triform, 166, 167, 168, 171
— at Haisborough, 104
Holvhead,150
INDEX.
275
Burners at Howth Baily, 159
Vienna Exposition, '251, 256
— Wicklow Head, 160
— used in French service, 190, 191, 203, 210
Button, central, in Doty burners, 74
Douglass burners, 74, 81, 86
gas-burners, 79
— Lepaute's burners, 212, 214
By-pass in gas-burners, 160, 162, 172
/CABLES, conducting, at La Heve, 224,
\J 229
— for English light-ships, 93
Cans, oil, at Blackwall, 91
manufactured by Barbier and Fenes-
tre, 206
Cape Elizabeth, lens manufactured for, 206
Carbon-points used in electric lamps, 68,
123, 225, 232, 237
Carcel burner the French unit of light, 187
Certificates required from applicants,
English light-keeper service, 97
French light-keeper service, 216
— given applicants, English light-keeper
service, 98
Chains, English, terms of contracts for, 93
Chain-wheels, used in revolving apparatus,
150
.Chance, Bros. & Co., manufactory of, 183
manufacturers of lens at Flam-
borough Head, 118
— Holyhead, 149
Longstone, 130
- Souter Point, 121
- South Foreland, 68
- Wolf Rock, 142
Channels, English system of buoyage, 96
Chart of Coquet, 128
Souter Point, 122
The Wolf, 141
Children of Scottish keepers, instruction,
177
Chimney-cap, Faraday's, 156
Chimneys, lamp, at Inner Fame Island, 130
— Douglass's, 87, 151
-for gas-light, 105, 162
modified Fresnel burner, 215
preserving from breakage, 119
srnoke-funnels for, 214
test of, 92
Church-service to be read by English light-
keepers, 115
Clergyman of Church of Scotland sent to
stations, 177
Clock-work of revolving machinery, pro-
vision for accident to, 122
— exhibited at Vienna, 251
Coal used at Haisborough grs-light, 106
Collinson, Admiral, 99, 131
Colza-oil. See Oil.
Commission des Phares, visit to, 184
executive officers, 185
furnishes designs for apparatus,
192
fixes scale of prices for apparatus,
192
— of Irish Lights introducing gas, 104
visit to, 158
Scottish Lights, 175, 178
Conducteur, French service, 218
Consumption of carbon-points at electric
lights, 123
gas, Douglass burner, 79
- Wighatn burner, 106, 163, 165, 169,
173
— oil, comparative, 81, 82, 83, 86, 87, 182,
190,196,198,201,211
tested in English service, 90
Doty burners, 195. 198, 201
Douglass burners, 83, 87, 190
— Lepaute's burners, 190, 191, 211
fuel, electric lights, 67
Coquet Island, description of light at, 127,
-chart, 128
division of area around, 129
Corporation of Trinity House, 20
Corps des Pouts et Chauss6es in charge of
the administration of the French light-
house service, 185
models exhibited by them at
Vienna, 250
Cost of change to electric light at La Heve,
241
of oils in France, 203
colza and mineral oils, 88, 190
dovetailing stone at the Wolfj 141
English buoys, 97
lights, decrease in, 18
— light-ships, 93
; lantern at The Start, 135
maintenance of electric lights, 245
gas-lights, 171
new French burners, 191
repairs to machinery at La Heve, 240
rock light-houses, (table,) 142
station at Souter Point, 125
substitution, gas for oil, 108,270
of electric for oil lights, 72, 270
— mineral for lard oil, 88
276
INDEX.
Cost of unit of electric light, 246
light iu France and the United
States compared, 269
Contents of rock light-houses, (table,) 142
Contracts, English, for oil, 89
ship-cables. 93
- French, for oil, 189, 197
Council chamber, at D6n6t des Phares, 185
Cowes, depot at, 132
Crane for moving buoys, Yarmouth, 101
setting up iron light-house tower, 254
Crew of English light-ships, pay, rations,
pensions, &c., 114
French light-ships, 249
— Seven Stones light-ship, 145
Cunningham, Mr. A., 176, 183
Cut-off for gas, automatic, 161.
Cylinder to produce red cut, 138
Cylindro - conical burner of Henry Le-
paute, 212
DABOLL trumpet, on Newarp light-ship,
113
at Dungeness, 40, 46
Day-beacons erected on Wolf Rock, 141
— towers serving as, 17, 108
— French system of coloration, 186
Deflector, interior. See Button, central.
Deflectors, arrangement of, 77
Delbeke, Captain, cited, 243
Department of Public Works, French,
models at Vienna, 250
De"p6t des Phares. visit to, 185
— at Blackwall,76
Yarmouth, 101
— on Isle of Wight, 132
Depots on English coasts, 97
Derham, cited, 38, 51, 52
Derrick used at Wolf light-house, 142
Diagram, illustrating revolving intermit-
tent gas-light, 163
Diameter of flames at Haisborough, 105
— lantern at The Start, 135
— English lantern, 155
— wicks of new French lamps, 201
Dimensions of burners fixed by French
government, 201, 211
Dingeys carried by English light-house
tenders, 131
Dinner at Lord Mayor's of London, 19, 74
— Trinity House, 132, 149
Disadvantages of electric lights, 247
Divergence of light from large flames of
gas-lights, 105, 170
Divergence of light from mineral-oil
flames, 200
Doty, Captain, interview with, 74
claims of, 74, 191
compensation by Scottish board, 181
French board, 191
— burner, description, 74
adopted by Scottish board, 181
gives same results as the modified
Fresnel, 191, 203
cost of, 192
first brought forward, 194,209
patent purchased by Barbier & Fe-
nestre, 207
variation of level in, 190, 207, 212
exhibited at Vienna Exposition, 256
Douglass, Mr., meeting with, 19
at Holy head, 149
his report on mineral-oil, 80
details of his improvements in burn-
ers, 78, 80, 86, 150
finished Wo]f Eock light-house, 140
extract from his narrative of the
construction of Wolf Eock, 142
Douglass burner, for oils, description of, 77,
82, 86, 150
— - variation of level in, 82
results with, 83, 84, 87, 169, 190
compared with American light-
house lamps, 88
gas-light, 104, 109, 110
at Flamborough Head, 118
Haisborough, 104
Holyhead, 150
value as compared with Doty
burner not settled, 181
for gas, 78
Dove, cited, 33
Dover, fog-signal experiments at, 22
— Castle, pharos in, 72
Drawings furnished by M. Allard, 225
Austrian government, 265
Duane, Gen. J. C., extracts from his report
on fog-signals, 58
Duke of Argyll, cited, 55
Dungeness, fog-trumpet at, 40, 46
Dunkerque floating-light, 201
Dwellings, keepers, English, 108
Scottish, 177
at Gunfleet, 100
- Honfleur, 219
La He ve, 241
Phare de PHOpital, 218
South Foreland, 66, 71
INDEX.
277
EARTH-CLOSET used at light-stations,
71
Echoes, aerial, 32, 35, 38, 39, 44, 46, 47, 50
Eddystone, description of, 136
Edinburgh, Duke of, 74
— industrial exhibition, models at, 180
Edinundson & Co., manufacturers of gas-
apparatus at Haisborough, 104
Edwards, Mr., 19
Elder Brethren of Trinity House, 21
yearly inspection made by, 131
Electric light at Grisnez, 225
Odessa, 226
Port Said, 225
Souter Point, 120
on Westminster clock-tower, 75
— how produced, 67, 123, 221
— lights, causes of irregularity in, 68, 237
comparison with oil-lights, 72 ^
gas-light, 75, 121
cost of maintenance, 72, 239, 246
machinery for, 241
substituting for oil, 72, 125, 241,
270
unit of, 246
disadvantages of, 247
intensity of, 70, 121, 238, 270
lantern proper for, 192, 232, 253
for shown by Sautter & Co., 206
— lenticular apparatus proper for, 121,
192, 252
of the world, 226
— opinion of Captain McCauley, 15
proper situation for, 248
power of penetrating fog, 121, 126,
243,244
range of, 242, 244
regulations at, English, 125
recommended for the United States,
269
— at La Heve, 220, 226
South Foreland, 66, 70
Elevator in light-house at Port Said, 225
Emerson, Mr., buoy-indicator of, 102
Engine, caloric, will work the siren, 62
Engineer of Trinity House, 19
Scottish light-house board, 178
— at electric lights, 125
— des Pouts et Chausse"es, 185
Engine-room at La Heve, 221
— Souter Point, 122
South Foreland, 66
at La Heve, 227, 236
replaced for more powerful
ones, 236
Souter Point, 122
Engines, steam, at South Foreland, 67
on Seven Stones light-ship, 146
Examination of English light -keepers, 97
French light-keepers, 216
Scottish light-keepers, 176
Exhibition, Industrial, at Edinburgh, 180
Vienna, 249
Experiments with fog-signals at Dover, 25,
22
lights on Westminster tower, 75
— colza and mineral oil, 80, 181 , 193, 195,
196
new Douglass burners, 87
oil and gas-lights, Haisborough, 110,
104
at Howth Baily, 167, 152
Doty burner, 195
Exterior deflector of burner, 77
Extinctions of electric-lights, La Heve, 233
TJ1ARADAY, Prof., cited, 151
wind-guard invented by, 156
Farquhar burner at Sautter, Lemonnier &
Co.'s, 206
photographs of flames at Vienna, 251
Fastnet Rock, view of, 17
Fatquville, 219
Feu-de-port at Honfleur, 218
Fire, means of extinguishing, at South
Foreland, 72
Flag-staffs at English stations, 108, 139
Flag, Trinity House, displayed, 108, 139
Flamborough Head, description of, 117
fog-gun station at, 118
Flames of gas-lights, photometric values
of, 170
mineral- oil burners,broader than colza
flames, 194
brilliancy obtained, 190, 195,202
old and new burners, 20
Farquhar burner, photographs ex-
hibited at Vienna, 251
Flashes in eclipse-lights, efforts of Fresnel
to prolong, 200
Flashing-point of mineral-oil, 188
Flexibility of gas-light, 111, 267
Floating lights, paperof M. Lepaute on, 204
apparatus for, 204
Fog, at Haisborough, 110
Souter Point, 126
— effect on electric lights, 126, 243, 214
j sound, 27, 49, 53, 54, 57, 59, GO
— obscuring high lights, 123, 157
— when dense, impenetrable to light, 111,
121, 126
278
INDEX.
Fog-bell, machinery for, constructing at
Blaekwall, 93
Fog-light at South Stack, 157, 266
would be of advantage on Pacific
coast, 127, 270
Fog-powers of Douglass burner, 151
electric light Souter Point, 121
-La Heve, 221, 241
gas-lights, 105
Fog-signals. See also Sound.
— adapted for different localities, 63, 64
— best form of boilers for, 25
— site for, 56, 63, 64
— causes of fluctuations in range, 29, 33,
38, 52, 53, 58, 59
— effective range of, 56, 57, 61, 64
— intervals between blasts, 57, 65
— sound-reflectors for, 179
— experiments near Dover, how conducted,
22
signals used, 22, 23, 61
pressure used, 22
questions considered, 23
— TyndalFs report, 25
Sir Fred. Arrow's remarks, 69
by General Duane, 25, 58
— American, opinion of Capt. McCauley,
15
— gun, qualities of, 23, 25, 42, 43, 46, 48,
49,63
— reed instruments, objections to, 62
— steam-whistle, qualities of, 23, 62
— best form of bell for, 25
— Austrian nebelhorn, 257, 261
— horns used simultaneously, 26
-DabolFs trumpet, 40, 42, 46, 113
— gong, 113
-Holmes' trumpet, 40, 42, 43, 125, 145
— siren, 37, 38, 39, 41, 45, 46, 47, 48, 51, 53,
56, 62
— Wigham's gas-gun, 174
— at Flamborough Head, 118
— Holyhead, 149
-Howth Baily,160
— Newarp light-vessel, 113
Seven Stones light- vessel, 145
— Souter Point, 125
— South Stack, 156
— St. Anthony, 137
— St. Catherine, 133
— The Lizard, 140
— The Start, 135
-Wolf, 143
in Scotland, 180
— on light-ships, 113, 145, 27-1
Fog-signals on transatlantic steamers, 16
Foundation for harbor light-house, 250
Four, phare du, model at Vienna, 250
French light-house service, notes on, 216
Fresnel, Augustin, first lens made by, 186
concentric gas-burner of, 199
efforts to prolong flashes in eclipse-
lights, 199
• — burners, invention of, 208
dimensions and intensities of flames
from, 209
air-tubes and overflow in, 208, 212
French engineers hesitate to alter,
199
modified by Lepaute, 210, 212
Fuel, tar used as, 106, 171
— for French light-house keepers, 216
Fund, mercantile marine, 21
Furniture, manufactured at Blaekwall, 92
— allowed English keepers, 109
French keepers, 216
/GALLERY, adjustable, in Douglass's
^ burners, 87
Doty lamp, 74
— photometric, at Blaekwall, 93
Gang-planks for small boats, 131
Gardiens of French service, 216
Gas, its use for light-house illumination,
75, 104, 159, 160, 169, 173
— how manufactured, 106, 159, 160
— consumption of, 79, 106, 166, 169, 171
— cost of, 171
— economy in use of, 162, 172
— means of producing uniformity of press-
ure, 159
— for illumination of beacons, 172
Gas-burner of Mr. Douglass, 78
• — Fresnel, 199
— M. Lepaute, 215
Mr. Silber, 79
- Wigham, 75, 104, 159-171
— for triform light, 166, 167, 168, 171
Gas-gun for fog-signal, 174
Gas-engine at Howth Baily, 160
Gas-holder at Haisborough, 106
— Howth Baily, 159
Gas-light apparatus, cost of, 170, 171
at Haisborongh, 104
Howth Baily, 159
Tuskar Rock, 2f>6
— Wicklow Head, 160
on Westminster clock-tower, 75
Wigham's patent, 161, 162, 165, ICC,
167
INDEX.
279
Gas-light, comparison with electric lights,
75, 121
oil-lights, 104, 109, 167
— cost of maintenance of, 182, 171, 172
substituting for oil, 108, 270
— divergence of, 105, 165
— experiments with, 167
- flexibility of, 104, 111, 173
— heat produced by, 105, 160
- intensity of, 76, 166, 169, 270
— less trouble than oil-lights, 161
— opinion of Professor Tyndall, 173
— power of penetrating fog, 76, 110, 173
— at Haisborough, 104
- Howth Baily, 159
Wicklow Head, 160
— on Westminster clock-tower, 75
— recommended for United States light-
bouses, 269
Gas-meters at Haisborough, 106
Gas-referees of London, cited, 112
Gas- regulator at Howth Baily, 159
Gas-works, Haisborough, 106
- Howth Baily, 159
- Wicklow Head, 160.
Gauge, for testing chimneys at Blackwall,
92
Gedney's Channel, New York Harbor, sug-
gestions of improvements in the marking
of, 266
Glass, cylindrical, for Ian terns, 107, 151, 154
— used for observing lights, 110
— lantern, broken by sea-fowl, 107, 154
Godrevy light-house, description of, 148
manner of lauding at, 148
Gong, on board Newarp light-ship. 113
Grace Darling, home and tomb of, 131
Gratuities allowed Scottish light-keepers,
177
French light-keepers, 219
Gravity, specific, of mineral-oils, 80, 88, 89,
188, 196, 197
mineral-oil required by French con-
tracts, 188, 197
— English contracts, 89
Grisnez, electric light at, 225
Gunfleet light-house, description of, 100
Gun, fog, at Flamborough Head, 118
Gun-metal, its use for window-frames, 143
H
AISBOROUGH, description of, 104.
— observations of oil and gas lights at,
109
Hauois light-house, cost and contents of,
142
Hawes, Mr., inspector Irish lights, 159, 175
Hawkshaw, Mr., 149
Head of Kinsale, view of, 17
Heat produced by gas-light, 105, 160
electric light, 252
six-wick burners, 189
— destroys ordinary burners when mineral-
oil is used, 83
Heaters used at American fog-signals, 146
Helices in magneto- electric machines, 67,
227
Herbert's Buoy, 95
Hetling, cited, 55
Hoffman, Colonel, 208
Holophone, Stevenson's, 179
Holophote, Stevenson's, 179
Holyhead, description of, 149
Honfleur, feu-de-port at, 218
H6pital; Phare de 1'. 217
Hopkinson, Dr., 184
Howth Baily, description of, 159
experiments at, 167
gas-gun at, 174
Humboldt, cited, 58
TLLUMINANT, question of the best, 19,
J- 190
Illuuiinants. See Electric light, Gas-light,
and Oil.
Inner Fame Island light, 130
Inscription, Phare de 1'Hopital, 217
Inspection, annual, made by Elder Breth-
ren, 131
Instructions, to English keepers, 97
— Scottish keepers, 176
Instruments, meteorological, atFatouvillc,
220
Insurance on life of English keepers, 98,
Scottish keepers, 177
Intensity, comparative, of gas and electric
lights, 75, 121, 270
oil-lights, 104, 109, 167, 169,
173
-oil and electric lights, 70,72, 121,
238, 270
- mineral-oils, 80, 196
and colza oil-lights, 81, 82,
83,85,86,87,181, 190, 195, 198, 1201,202,
211
— lard-oil lights, 88
sound, 51
Dory burner, 181, 191 , 195, 203
280
INDEX.
Intensity of Douglass burner, 78, 82, 83, 84,
87, 151
Farquhar burner, 206
Fresnel burner, 209
Lepaute's burners, 210, 211
— Wigham's gas-burners, 75, 110, 166
169
— triform gas-burners, 75, 166, 169, 170
— Maris lamp, 194
Irish Board, opinion as to use of gas, 172
— visit to, 158
— lights, gas introduced at, 104
— view of those on the southern coast,
158
JAY, Hon. Mr., 250, 266
Jets of Wigham's gas-burner, 105, 160
Junior Brethren of Trinity House, 21
dinner in honor of, 132
KEEPERS, English,regulations concern-
ing, 97
transportation of family, 109
— salaries of, at electric lights, 125
— Scottish, regulations concerning. 176
— French, to test oils, 189
regulations concerning, 216
— foreign better than those of the United
States, 271
— at Dungeness, 125
- Fatouville, 219
Gunfleet, 100
Haisborough, 106
- Howth Baily, 160
— Honfleur, 219
Longstone, 131
- — Lizard, 140
— La Heve, 221,233
- Phare de 1'Hopital, 217
-— Sou ter Point, 125
— South Foreland, 71, 125
— St. Catherine, 134
— The Wolf, 143
Key West light-station, shadows cast by
sash-bars, 153
Kinsale, Old Head of, light-house as day-
mark, 17
LA HEVE electric lights, description of,
2-20,226
Lamp-chimneys. See Chimneys.
Lamp-guard at Whitby, 118
Lamp-shop, Black wall, 76
Lamp- valves, how made, 206
Lamp, Doty. See Doty burner.
— Douglass. See Douglass burner.
— Fresnel. See Fresnel burner.
— electric. See Regulator, electric.
— Maris, description of, 193
— constant-level, when used, 194
— oil, used at electric and gas lights in
case of accident, 70, 105, 122, 129, 159,
162
— at Fatouville, 220
Holy head, 150
— Souter Point, 123
Lamps, used for testing oil at Blackwall,
90
different orders of lights, 189, 208
— keepers instructed in use of, 97, 176
— changed semi-monthly at French sta-
tions, 220
— tested at D6p6t des Phares, 157
Landing at Godrevy, 148
Wolf Rock, 142
Lantern at Blackwall, 92
Gunfleet, 100
Grisnez, 225
Holyhead, 151
- La Heve, 221, 232
Souter Point, 124
Spurn Point, 116
The Lizard, 124
— for The Start, 135
— model at Edinburgh, 180
— made by Sautter, Lemonnier & Co., 206
Barbier and Fenestre, 206
Lantern-gallery, floor of, 143
Lanterns, for electric lights, 71, 107, 125,
192, 206, 232, 253
gas-lights, 162
oil-lights, 151, 192
light-ships, 92, 205
— glass for, 107, 154, 192
— English, dimensions of, 71, 155
have diagonal sash-bars, 19, 125, 143
151
— parapets of, 19, 154, 206
ventilation of, 107, 143, 154, 155
painted by keepers, 108
Lard-oil. See Oil.
Lees, Mr., 158, 175
Lens, for verifying position of electric
light, 222, 232
Lens-makers, Barbier & Fenestre, 207
— Chance Bros. & Co., 1^3
— M. Lepaute, 204
— Sautter, Lemonnier & Co., 206
INDEX.
281
Lenticular apparatus, for electric lights,
19:3, 241, 252
— floating lights, 204, 205, 271
- gas-lights, 162, 165, 166, 167
- range-lights, 180, 251
calculated for different heights, 208
revolving, worked by hand, 122, 270
proper intervals of, 57
areas of red and white panels,
118, 143, 270
manufactory of Chance Bros., 183
manufactories at Paris, 203
M. Reynaud offers to test, 192
at Coquet, 128
Fiamborongfa Head, 118
- Holyhead, 149
Inner Fame Island, 130
- La Heve, 223, 226, 229, 232
- Plymouth, 138
— Souter Point, 121, 122
the Eddystone, 137
-— Lougstone, 130
— Needles, 134
Start, 135, 184
Wolf, 142
Vienna Exposition, 251
-Wieklow Head, 160
-Whitby, 119
— for Cape Elizabeth, 206
— Longships light-house, 184
— Swedish light-ship, 204
used at Howth Baily experiments,
on Westminster clock-tower, 75
Lcpaute, M., visit to his manufactory, 204
burners manufactured by, 191, 203,
205,209,210,212,215
paper on burners, 208
— floating lights, 204
articles exhibited at Vienna, 251
Light-house administration, benefits of
permanence in, 183
English, vested in Trinity House, 20
French, vested in Corps des Ponts et
Chaussdes, 185
foreign better than that of the United
States, 271
— illumination, requirements of, 18,111,
121, 173
— List, English, extracts from, 117, 122,
128, 134
Light-houses, models at D6pot dew Phares,
185
— Edinburgh, 180
Trinity House, 122
Light-house, models at Vienna Exposi-
tion, 250
— screw-pile, 99
— iron ft Vienna Exposition, 256
Light-keepers. Sec Keepers.
Light-sbip, needed on Rose and Crown
Shoal, 15
— lantern for, constructing at Black wall,
92
— design of one for Sweden, 204
Light-ships, apparatus for, 18, 76,115,181,
204
— bilge- keel for, 104
— moorings for, 93
— regulations for English service, 114, 146,
French service, 249
— repaired at Blackwall, 93
— of iron no longer built in England, 93
— none in Scotland, 181
— with revolving lights, 271
Letter from Commissioners Irish lights,
158
the Due de Broglie to English em-
bassador, 191
Mr. Douglass, 79
- Hon. Mr. Jay, 258
M. Reynaud, 190
Level, oil drawn from more than one, 91
— means of varying, 212, 214
— proper for oil in burner, 81
Libraries at light-stations, 108, 177
Lightning-rods at light-stations, 108, 138
Light, fog, at South Stack, 157
— increase of, at Howth Baily, 159
— intermittent, at Wieklow Head, 160
— obstructed by vertical sash-bars, 151
— utilization of the rear or landward, 122,
271
Lights, electric. Sec Electric lights.
— gas. Sec Gas-lights.
— range. See Range-lights.
— oil. See Oil.
— American, opinion of Captain McCauley,
15
— high, obscured by fog, 127, 157, 270
— kept by English local authorities, 20
— results desired for, 112
Lime for removing sea-weed, 147
Liverpool, docks at, 18
Lizard lights, description of, 159
Longships light, description of, 146
Longstoue light, description of, 130
Low light, use of, .on Pacific coast, 127,
157, 270
at Coquet, 127
282
INDEX.
L<!\v light at Plymouth breakwater, 138
— St. Anthony, 137
— Souter Point, 70, 122
South Stack, 157
— The Start, 135, 184
1U-ACHINE-SHOP at Blackwall, 92
Machine-rooms at La Heve, 221.
Machines, magneto-electric, at La Heve,
221
South Foreland, 67
Souter Point, 123
— polishing, at Chance Brothers', 183
Paris, 203
Machinery, at La Heve, cost of repairs,
240
— for firing gas-gun, 175
— log-hell, constructing at Blackwall,
93
fog-bells in English service, 137
fog-signal, Holyhead, 149
Seven Stones light-ship, 146
Souter Point, 125
— South Stack, 156
— St. Anthony, 137
— The Wolf, 143
intermittent gas-light, 162
— revolving, flat wheels for, 150
— at South Stack, 157
Vienna, 251
McCauley, Captain, conversation with, 15
Magnets used at electric lights, 67, 123,
227
Magneto-electric machines at La Heve,
221, 227, 236
South Foreland, 67
— Souter Point, 123
Maintenance of electric light, cost of, 72
— gas-light, cost of, 162, 171, 172
Maltre de phare. See Keepers, French.
"Manacles, The," low light at St. Anthony,
to mark, 137
Mangon, M.; results of tests of, with paraf-
fine, 196
Manufactory of Chance Brothers & Co.,
183
— Barbier & Fenestre, 207
— Lepaute, 204
— Sautter, Lemounier & Co., 206
Manufactories near Souter Point, 120
Mapliu Sands light-house, description of,
99
Maris lamp, description of, 190
Masonry, comparative sections of, 141
Mast, steel, for lantern of light-ship, 92
Mayor of London, dinner given by, 19,
74
Measurements, Seven Stones light-ship,
146
Media, glass, for observations, 110
Medicine-chests at English light-stations,
108
Members of the Corporation of Trinity
House, 21
Scottish light-house board, 178
French light-house board, 184
Mercantile marine fund, English, 21
Mersey, buoyage of, 18
Meteorological observations at South
Foreland, 72
on English light- vessels, 115
at French light-stations, 220
Meters, gas, at Haisborough, 106
Middle ground in channels, English sys-
tem of buoying, 96
Mineral-oil. See Oils.
Minot's Ledge light-house, 142
Mirrors on French bell-buoys, 186
Model of Stevenson's holophoue, 179
Models in De"pot des Phares, 185
— at Trinity House, 122
Vienna Exposition, 250
— of light-houses at Edinburgh exhibi-
tion, 180
Modified Fresnel burners, chimneys of,
215
description of, 210
tables of, 210, 211
used in the French service, 191,
203
Moodie, Captain, conversation with, 266
Moorings of buoys, 93
English light-ships, 93
Newarp light-ship, 113
Rundlestone bell-buoy, 144
Seven Stones light-ship, 93, 146
Morton, Mr., 129
Mucking light-house, description of, 99
Museum at Dep6t des Phares, 186
•VTANTUCRET SHOALS, badly lighted,
JLl 15
Naval review at Spithead, 132
Nebelhoru, Austrian, description of, 257,
281
Needles, The, description of, 134
Netherlands, Kingdom of the, adoption
of Lepaute's burner by, 209
Newarp light-ship, description of, 113
INDEX.
283
New Castle, ordnance-works at, 120
North Stack fog-signal station, descrip-
tion of, 155
Note of fog-signals most useful, 38, 39,
45, 46, 48, 113
0
AK, for window-frames, 143
Observation of lights at Haisborough,-
109
Howth Baily, 167
light at Souter Point, 126
Observations, meteorological, at Fatou-
ville, 220
South Foreland, 72
— on English light-ships, 115
Odessa, electric light at, 226
Oil-butts, St. Catherine's, 133
— South Foreland, 71
Oil-cans at Blackwall, 91
— for mineral-oil, 206
Oil-cellars, Haisborough, 107
Oil, foreign contracts, 89, 197
— how stored at Blackwall, 91
— cans for delivery of, 91
— not stored by the French, 187
— special trial of, made by Scottish keep-
ers, 17.S
— Trinity House, purchases for other gov_
ernments, 91
Oil, colza, color and odor of, 71
— qualities compared with mineral-oil,
84, 85, 87, 182, 201
required by foreign contracts, 90,
389
results when used with new burners,.
88
tests of, 90, 189
Oil, mineral, accidents from use of, 194,
195,198
adopted by foreign governments, 19,
181,190,193,268
economy in use of, 19, 85, 88, 182, 202,
268
— experiments with, 20, 80, 181, 193, 195,
196
— qualities of different samples, 80, 196
as compared with colza-oil, 84, 85,
87, 182, 201
lard-oil, 88, 268
required by contracts, 89, 197
— tests of, 89, 90, 187
cost of, 85, 88, 182, 190, ifo
— — precautions taken with, 99, 17S, 189
cans for, 206
Oil, mineral, regulation of overflow, 82, 190,
207, 212
Chairman United States Light-House
Board on, 195
Mr. Douglass on. 80
M. Reyuaud on, 193
Ordnance-works of Sir Wm. Armstrong,
120
Orfordness" light, description of, 101
Osnaghi's reflector, 262
Outer Fame Island light, description of
130
Overflow of oil, adjustment of, 82, 190, 207,
212
PACIFIC COAST, suggestions for fog-
lights on, 127, 157, 270
Painting of towers and buildings, English
service, 108
Palmyre, phare de la, model at Vienna,
250
Panels, flash, for new lens at Start Point,
184
proper ratio of red and white, 118,
142, 270
Paraffiue. See Oil, mineral.
Parapet of English lanterns, 19, 154, 206
Patent, Doty's, infringement claimed, 74
— Silber's, for gas-burner, 79
— Wigham's, for gas-lights, 169
Pelz,Mr. P. J.,271
Pensions to English light -keepers, 98
light- vessel crews, 115
French light-house keepers, 216
Scottish light-house keepers, 177
Permanence desirable in light-house ser-
vice, 183
Phoros in Dover Castle, 72
Photographs of American light-houses, at
Vienna. 266
Farquhar burner, at Vienna, 251
Photometer used at Blackwall, 90
Depot des Phares, 187
by French lens-makers, 208
— Hopkinson's, 184
Photometric experiments, rooms for, at
Trinity House, 22
Blackwall, 93
D6pot des Phares, 187
Piles, electric, formerly used at La Heve,
226.
— of Gunfleet light-house, 100
Mapliu Sand light-house, 99
Swedish light-house, at Vienna, 257
Pinnace, carried by English tenders, 131
284
INDEX.
Plymouth breakwater light, description
of, 137
Poe, Col. O. M., 144
Point Bonita, Cal., resembles Start Point,
England, 136
Point Roche, view of, 17
Port Sa'id, electric light and elevator at,
225
Power of burner for fixed gas-light. 169
English lights increased, 78, 85
first-order sea-coast lights, 121
— fog-signal at Vienna, 261
— gas-light Westminster clock-tower,
76
lens at Souter Point, 121
light at Grisnez, 225
La Heve, 221, 238, 242,244
South Foreland, 70
machines at South Foreland, 67
Souter Point, 123
magnets at South Foreland, 67
Osnaghi's reflector, 264
Powers of oil and electric lights compared,
72, 121, 225
— illuminating, of oils, 90
— gas-lights, 169
Prices of apparatus fixed by Commission
des Phares, 192
for electric lights, 241
oil, colza, 81, 197
- mineral, 85, 88, 89, 182, 190, 197
• — lard, 88
— Wigham's gas-apparatus, 170, 171
Prisms, machines for polishing, 183, 203
— removed for triform apparatus, 166
— tested by M. Sautter, 206
rjUEENSTOWN HARBOR, buoyage of, 17
Questions to be considered at Dover fog-
signal experiments, 24
EAIN, its effect on sound, 26, 37, 40, 45,
46, 48, 50, 52, 59, 60
Ramsay, Captain, U. S. N., 22
Range, effective, of fog-signals, 56, 57, 61,
64
— of electric light, 112, 242, 244
fog-signal at Vienna, 262
Range-lights, apparatus for, 180, 251
Bill of Portland, 135
— Fatouville and 1'Hdpital, 219
— Orfordness, 101
— Whitby, 118
Range-lights on English coast, 116
Rations for English keepers, 98, 114
French keepers, 216
Scottish keepers, 177
Ratio of areas of red and white panels in
flashing-lights, 118, 142, 270
increase of lights by apparatus, 169,
264
Raynolds, Lieut. Col. W. F., 144
Rear light, utilization of, 122, 271
Red-cuts at Coquet, 127
Godrevy, 148
Longships, 147
Orfordness, 101
Plymouth breakwater, 138
Souter Point, 122
Spurn Point, 116
Start Point, (in new lens,) 184
The Needles, 134
Whitby; 118
— recommended for United States light-
house service, 270
Reflector-apparatus, for light-ships, 76, 271
— still in use in English light-houses, 7G
— requires constant-level lamps, 194
— made by the elder Stevenson, 179
— for harbor and ship lights, 179
-> fog-light, South Stack, 157
Dunkerque light-ship, 204
— at Gunfleet, 100
South Stack, 157
The Cockle, 115
Eddystone, 137
Lizard, 139,140
Longships, 147
Vienna Exposition, 262
— Whitby, formerly used, 119
Reflector for sound, 23, 58, 179
Regulations as to care of oils, 99, 178, 189
— concerning English service, 97, 114
French service, 216, 249
Scottish service, 176
Regulator, electric, at La Heve, 230
Souter Point, 123
— South Forelaud, 68
— gas, at Howth Baily, 153
— oil, in Douglass lamp, 82
— used in fixed gas-light, 161
Repairs, English keepers taught to make, 98
— general, made by superintendents En-
glish lights, 131
— to machinery at La Heve, 240
Report of Chairman United States Light-
House Board on clangers of mineral-oil,
181
INDEX.
285
Eeport of Mr. Douglass on oils and burn-
ers, SO
General Duane on fog-signals, 58
United States Light-House Board for
1873, extract, 9
— Scottish board on lamps and oils, 181
— Professor Tyndall on effect of sash-
bar shadows, 152
— gas-lights, 163, 173
fog-signals, 25
— preliminary, to the Light-House Board, 9
Review, naval, at Spithead, 132
— of troops at Dover Castle, 72
Revolving apparatus. See Machinery.
Reynaud, M., meeting with, 190
— offers to test apparatus for the United
States, 192
his paper on mineral-oil, 193
Rings of jets in gas-burners^ 161
Robinson, Dr., cited, 27, 51, 56
Rochemont, M. Quinette de, his paper on
electric lights at La Heve, 226
cited as to shadows of sash-
bars, 153
Roches Douvres, phare des, model at Vi-
enna, 250
Rock light-houses, sections of, 141
examples in the United States, 142
cost and contents of, 142
rations of keepers at, 98, 216
Rooms for engineer at French stations,
218
— photometric experiments, Trinity
House, 22
Black wall, 93
Depot des Phares, 187
— officers, South Foreland, 71
Rose and Crown Shoal, needs to be marked
by a light-ship, 15
Rouen, visit to, 215
Royau, phare de, model at Vienna, 250
Rundlestoue bell-buoy, 144
IS
AILING, date of, 9, 15
Sailing-directions for Coquet, 128
— Souter Point, 122
— The Needles, 134
St. Anthony light, description of, 137
— Catherine light, description of, 133
Salaries of Elder Brethren of Trinity House,
21
— English keepers, 98, 125
light-ship crews, 114
French light-keepers, 216
Salaries of French light-ship crews, 249
Scottish light-keepers, 176
Sash-bars, diagonal, best for electric light,
192, 232
used in English lanterns, 19
first designed by the elder Steven-
son, 180
at Holyhead, 151
Haisborough, 107
Souter Point, 125 .
Spurn Point, 117
— The Stack, 135
— vertical, effect of shadows cast by, 151,
152, 153
Sautter, Lemonnier & Co., manufactory of,
206
articles exhibited at Vienna, 251
tests of prisms and apparatus
by, 206
Saving to the United States by adoption of
mineral-oil, 88
new burners, 88
Schenck, General, 22
Scottish light-house board, members of, 178
report on oil and lamps, 181
subordinate to Board of Trade, 21
when established, 178
Screw-pile light-houses, Gunfleet, 100
— Maplin Sand, 99
comparative cost of, 101
Sea-fowl break lantern-glass, 107, 154
Sea- weed, means of removing, 147
Seven-Stones light-ship, description of, 146
moorings of, 93, 145
Shadows cast by vertical sash-bars, 151,
152, 153
— sound. See Sound-shadows.
Shoals off Queenstown, how marked, 17
Signals to vessels in danger, on English
light-ships, 115
Silber, Mr., his patent gas-burner, 79
Siren, principle of, 37, 45
— superiority of, 39, 41, 46, 47, 48, 51, 53, 56,
62
— echoes produced by, 38, 39
— best pitch for note, 47
— means of rotating desirable, 56
— with compressed air, 56, 62
Skerry vore light-house, 142
Smalls light-house, 142
Smeaton, John , 136
Smoke-funnels, Lepaute's, 214
Sound, causes of fluctuations in range, 29,
33, 38, 52, 53, 58, 59
acoustic opacity, 53, 55
286
INDEX.
Sound, effect of changing direction of, 41,
50, 51, 64
fog- on, 27, 49, 53, 54, 57, 59, 60, 115
height on, 26
— pitch on range of, 38, 39, 45, 46, 48
rain on, 26, 37, 40, 45,46,48,50,52,
59,60
snow on, 52, 58, 59, 60
wind on , 46, 51 , 61
— intensity of, 51
— reflection, aerial, of, 31, 32, 35, 38, 39, 44,
46, 47, 50, 58, 59
— Arago, cited, 34
— Derham, cited, 38, 51, 52
— Dove, cited, 33
— Duke of Argyll, cited, 55
— Hetling, cited, 55
— Huinboldt, cited, 58
— Robinson, cited, 27, 51, 56
Sound-shadows, effect of, 16, 26, 41, 42, 43,
56, 64, 133
Souter Point light, description of, ISO
observation of, 126
South Foreland, fog-signal experiments at,
22
lights, appearance from Dover pier, 70
description of, 66
means of extinguishing fire at, 72
— Stack, description of, 156
low light at, 157, 266
Speaking-tubes, South Foreland, 71
— La Heve, 223
Specific gravity. See Gravity, specific.
Spectacle Reef light-house, by whom built,
144
Sperm-candle, the English and American
standard unit of light, 81
Spithead, naval review at, 132
Spools of magneto- electric machines, 67,
227
Spurn Point light, description of, 115
Stairs at Haisborough, 106
South Foreland, 71
Whitby,118
Start Point light, description of, 135
new lens for, 184
Steamers, need of fog-signals on, 16
Stevenson, Mr. Thomas, 179, 183
his differential reflector, 179
apparatus for ship and harbor
lights, 180
— holophone, 179
holophote, 179
— Messrs., engineers of Scottish board, 178
— the elder, his lantern with diagonal
bars, 180
Stone-courses, Wolf Rock light-house, 141
— Longships, 147
Stones, The, buoy off Godrcvy, 148
Stores, Scottish keepers report quality of,
178
Store-houses, Yarmouth depot, 101
Store-rooms, South Foreland, 71
Strata, moving, at St. Catherine's light, 133
Superintendents of Trinity House make
repairs, 131
have charge of tenders, 97
Supernumeraries in English service, 97, 98
Swedish light-house at Vienna, 256
— light-ship made by M. Lepaute, 204
Switches for changing currents at electric
lights, 228, 229
rPABLE showing qualities of different
A mineral-oils, 80, 196
— of results of experiments with Doug-
lass burner and different oils, 81, 82, 83,
84, 86, 87
old and new French burn-
ers and different oils, 198, 201, 209, 210,
211
salaries of English light-house keep-
ers, 98
and rations of English light-ship
keepers, 114
, Scottish light-house keep-
ers, 176, 177
cost and contents of rock light-
houses, 142
experiments with gas-light, 168
illuminating powers of gas-lights, 169,
170
increase of intensity in eclipse-lights
by use of mineral-oil, 202
expenses of electric light at La Have,
239, 246
hours of illumination and the work-
ing of the engines, La Heve, 240
comparative range of electric light,
244
observations of oil and electric lights,
244
Tanks, mineral-oil, in Scottish light-houses,
178
French light-houses, 198
Tar, use of, as fuel, 106, 171
Tenders, English, in charge of superin-
tendents, 97
description of, 131
Test, for chain-cables for English light-
ships, 93
INDEX.
287
Test of apparatus at Blackwall,97
— D6p6t des Phares, 187
offer of M. Reynaud, 192
at Chance Brothers, 184
Sautter, Lemounier & Co's, 206
- — lights, at Haisborongh, 110
oil at Black wall, 90
French light-houses, 189
Scottish light-houses, 178
Tips for burners in Douglass lamp, 77, 83,
80
— removable, 83, 86
Tower at Coquet, 129
— Eddystoue, 136
Longships, 146
— Plymouth breakwater, 137
St. Anthony, 137
St. Catherine on moving strata, 133
Souter Point, 124
- Wolf Rock, 141
— exhibited at Vienna by Sautter, Le-
monnier & Co., 254
Towers as day-marks, 17, 108
— atBlackwall for testing purposes, 97
— Haisborough, 106, 107
Phare de ITlopital, 217
South Foreland, 71
Spurn Point, 115
— English and American, comparative
merits, 106
Transportation, English keepers, 109
Triform gas-light. See Gas-lights.
Trinity House, London, 18
— acts as agent for purchase of oils, 91
ceased to build iron light-ships, 93
corporation of, 20
dinuer given by, 132, 149
engineer of, 19
lamps and burners received from, 88
members of, 21
powers of superintendents of, 97
subordinate to Board of Trade, 21
Tripoli, Canard steamer, accident to, 17
Trumpet, DabolPs, at Duugeness, 40, 46
in Dover experiments, 42
on Newarp light-ship, 113
— Holmes, in Dover experiments, 43, 46
— at Souter Point, 125
Seven Stones light-ship, 145
Tuskar Rock, view of, 17
gas-light on, 266
Tyndall, Professor, his opinion of gas-
lights, 104, 163, 173
sash-bars obscuring light, 152
report on fog-signal experiments,
25
UNIFORMS worn in English light-house
service, 98, 109, 114, 139
Unit of light, photometric, English, 81
— French, 187,196
---- comparative values of French
and English, 187
--- cost of, in France and the United
States, 269
— cost of, when produced by elec-
tricity and oil, 246
Utilization of landward light, 122, 271
TTALVES, lamp, made by Lepaute, 206
Ventilation of English lanterns, 107, 143,
154, 155
Vestal, description of, 131
Vienna Exposition, 249
ALES, PRINCE OF, 149
Walls at Longstone, 130
Spurn Point, 117
Watch of keepers, 71, 126.
Watch-room at Souter Point, 122
- Phare de l'H6pital, 217
English, size of, 71
painted by keepers, 108
Water at South Foreland, 72
— supplied at La Heve, 233
Washing, allowance for, to Scottish keep-
ers, 177
Webb, Captain, 18, 132, 144
Weller, Captain, 99, 131
Westminster clock-tower, lights on, 75
Wheels of revolving machinery at Holy-
head, 150
Whistles, best form of bell, 25
— on steamers as fog-signals, 16
— qualities as fog-signals, 23, 62
Whitby light, description of, 118
Wicks, care taken in purchase of, 189
— concentric, separation in burners, 209
— effect of different oils on, 84
— for French mineral-oil lamps, 201
— in six-wick lamp, 151
— tested as to effect of combustion on, 90
— used in Douglass burners, 81
Wigham, Mr., description of his gas-lights,
161-167
— his apparatus at Haisborough, 104
burner, used at Westminster clock-
tower, 75
gas-gun for fog-signal, 174
— offer to erect apparatus in United
States, 171
288
INDEX.
Mr. Wigham, his plan for illuminating bea-
cons with gas, 17
Wind, its effects on sound, 46, 51, 61
Wind-guard at North Stack, 155
Wind-vanes at English stations, 108
Window-frames at English stations, 143
— at the Wolf, 143
— of low light-room, Souter Point, 122
Wolf Rock light-house, plans of, 19
description of, 140
Wood, used for sound-reflectors, 179
Wrecks, English system of buoying, 96
VERMOUTH, buoy-depot at, 101
Young's paraffine used by French govern-
ment, 197
P7ONE of maximum intensity in six-wick
Li burners. 78
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