enabled a great practical improvement to be effected. Incan-
descent lighting by acetylene gas will probably give still better
results, at any rate, as regards light efficiency. The intrinsic
brightness of various systems of lighting employed in lighthouses
is as follows, expressed in carcels(*) per square centimetre of the
mean horizontal focal plane of the luminous source. It varies
from 0.35 to 1. 1 8 carcel for burners with mineral oil, employing
from one to six wicks; and for incandescent lighting with com-
pressed oil gas, petroleum vapour, and acetylene, it attains 2, 2.5,.
and 4 carcels, respectively. The crater of an electric arc has an
intrinsic brightness of 900 carcels.
The luminous efficiency of the optical apparatus has been in-
creased by improving the focal precision, and by keeping the
characteristic or effective divergence within narrow limits.
With lightning lights, by reducing the duration of the flashes, as
far as possible, to the time actually required for the full perception
* i carcel equal* 9.5 candles.
LIGHTING AND BUOYING OF THE COASTS OF FRANCE. 91
of their luminous intensity, it has been possible to construct the
optical apparatus with a small number of lenses of large surface,
and consequently of great power.
The illuminating power has thus been raised to 50,000 and
60.000 carcels in lighthouses which have double sets of optical
apparatus, such as at Ailly, where the illuminant is compressed
gas; and at Vierge, where it is compressed petroleum vapour.
Although the increase of the intrinsic brightness of the luminous
source exercises the principal influence in increasing the illuminat-
ing power of lighthouses, it is, nevertheless, necessary to consider
to some extent the dimensions of that source.
Incandescent gas lighting, when no special gas works are required,
is not much more expensive than lighting with a three-wick burner ;
and even when special works are necessary, it is more economical
than a five-wick burner. The annual expenditure for gas lighting
does not exceed 1800 francs (^72) with gas works, or 800 francs
(^32) without works; for petroleum vapour lighting it amounts to
650 francs (^26).
The generating stations for recently-built electric lighthouses
have been provided with the latest improvements; particular
attention has been paid to the improvement of the alternators and
The permanent lights have increased the safety of navigation
by enabling the beacon towers and shoals out at sea to be
illuminated, where the erection of ordinary lighthouses would have
been precluded on account of the expense. These permanent lights
employ wicks, the surface of which has been evenly coated with a
thin layer of carbonised tar, the operation being termed " crontage,"
or caking. These permanent lights can have all the character-
istics of superintended lights.
The consumption of oil is from 35 to 40 grammes (1.234 to
1.411 oz.) per hour. The illuminating power of these lights
averages about 100 carcels for regular lightning lights, from 85 to
60 carcels for lights with groups of two or three flashes, and 8
carcels for fixed lights.
Other permanent lights, in the form of illuminated buoys, fed
with oil gas, have been adopted on an extensive scale, especially
to increase the protection at dangerous points, or as substitutes
for lightships, and for lighting winding and shifting channels.
Considerable improvements have also been effected in the con-
struction of lightships
1. By eliminating synchronism between the period of oscillation
of the lightship and that of the waves acting upon it.
2. By reducing the rolling due to the waves by the addition of
side keels to the vessel.
The information afforded by the various trials and experiments
92 LIGHTING AND BUOYING OF THE COASTS OF FRANCE.
carried out with the Talais and Snouw lightships has been utilised
for the design of the lightship which is to be moored on the
Sandettie. This vessel will be 35 metres (114 feet 10 inches) long,
6.24 metres (20 feet 5 inches) wide, with a depth of 5.10 metres
(16 feet 8J inches) from the deck to bottom of hold, at centre.
It will have a displacement of 342 tons.
The illuminating portion will consist of a swinging optical
apparatus for a lightning light, with an incandescent burner em-
ploying compressed oil gas as an illuminant. The illuminating
power will be 3500 carcels.
The vessel will, in addition, be provided with plant for the
sounding signal. This will comprise two boilers with distilling
plant, self-condensers, and air-compressers ; and a single siren
worked by compressed air, with reservoirs and accessories.
It has been observed that the vibration and noise which occur
in beacon towers are the effect of the impact of the waves.
Considered from this point of view, in which the essential factor
of resistance is the whole mass of the tower, it has been found
advisable to build the latter in the form of a monolith.
Thus the most recent lighthouses at sea have been built with
small stones set in Portland cement, with a facing of small pick-
dressed stones. Similarly, beacon towers are constructed of
concrete or of neat cement, deposited within framing. This
simplified method of construction is economical and rapid, and,
moreover, it increases the resistance of the work to the principal
stresses to which it is subjected.
The Discussion was combined with that on the papers by Mr.
D. A. Stevenson, Mr. Harding, and Mr. Brebner (see p. 97.)
On the motion of the Chairman a vote of thanks was accorded
to the author.
THE CHINESE LIGHTHOUSE SERVICE/'
Paper by J. R. HARDING.
THE lighthouse service of China is a department of the Chinese
Imperial Maritime Customs, which institution has, under the able
administration of Sir Robert Hart, become practically the Inter-
national Civil Service of the country, embracing within its com-
prehensive grasp many important undertakings other than the
collection of revenue.
The paper is divided into the following seven sub-headings :
(i) Commencement of lighting the coast; (2) Description of the
more important lights in chronological order; (3) The lighting of
the Yangtze; (4) Fog signalling, oil storage, etc; (5) Staff; (6)
Buoys and beacons; (7) Construction and maintenance.
1. When Sir Robert Hart first joined the Customs Service in
1859 the coast was practically unlighted, and the work of
establishing suitable safeguards for shipping was only commenced
in earnest in 1869, in which year Mr. D. Marr Henderson,
M.Inst.C.E., was appointed engineer to the Lighthouse Depart-
ment, where he remained until 1898.
The designs for most of the lights on the Chinese Coast were
prepared, by Mr. Henderson, and their erection was carried out
under his directions.
2. A brief description is given of all the lights of any importance
on the Chinese coast, and plans of the various stations accompanied
the paper, with a chart showing the positions and characteristics of
the lights. Among the most interesting stations are : BREAKER
POINT, about 30 miles south of Swatow. The tower, which is 120
feet in height to the lantern vane, was designed by Mr George
Rendel, and consists of a wrought-iron cylinder or tube, made in
sections and bolted together, containing a spiral stairway. The
tube is enlarged at the top to a diameter of 12 feet, to form a
service room and to carry the lantern, and it is stayed with eight
large wrought iron stays, arranged in pairs, braced together, and
secured to anchor-bolts embedded in Portland cement concrete.
The tower was cheap, easily erected, and, what is of even more
importance on the Chinese coast, easily transported and landed.
The light is first-order dioptric white occulting, the occultations
94 THE CHINESE LIGHTHOUSE SERVICE.
being produced by an iron cylinder of slightly larger diameter than
the burner, alternately raised and lowered by a suitable clockwork.
SOUTH CAPE OF FORMOSA. The interest attached to this station
lies in the fact that it was built in a part of the island inhabited
solely by savages, and had, in consequence, to be fortified. The
lantern was protected by steel revolving screens, and on the galler>
of the tower, which was of cast iron, a machine gun was fitted on
racers. Round the base of the tower was built a wrought iron
refuge or fort, communicating by bullet-proof passages with all the
rooms in the keepers' dwelling-houses. Both fort and tower were
fitted with suitable accommodation for the staff in case of siege,
had water-tanks in the basement, and were supplied with a stock
of provisions. The station was further protected bv a loop-holed
wall and a dry ditch, flanked by two small towers or caponnieres.
armed with iS-pounder cannon. PEI-YU-SHAN. A fine hyper-radial
light, floated on mercury, showing double flashes every half-
A description is given also of a composite light-ship, no feet
long by 25 feet beam, which has been recently built in Shanghai,
and which shows a triple white flash, and is fitted with a powerful
double-noted fog siren, operated by two 9^ horse power Hornsby-
Ackroyd oil engines.
3. The Yangtze, which is probably the third largest river in the
world, is navigable for deep-draught steamers up to Hankow, a
distance of 620 miles; for light-draught steamers to Ichang, a
further distance of 370 miles; and for special steamers as far as
Chungking, another 400 miles, and perhaps even further.
The lighting is carried out with sixth-order lens lanterns, hoisted
on suitable masts on shore, or on native craft fitted as light-boats,
and attended to by native light-keepers.
Gas buoys on Pintsch's system are now being provided for use
in the Yangtze, and it is hoped that some will be in position early-
4. Fog-signalling is undertaken mostly with cast-iron cannon,
but four of the most important shore stations and three of the light-
vessels are provided with sirens. A table is given, showing the
average number of hours of fog during the year at various points on
The stations are supplied with water by large, underground
cisterns, which are filled with rainwater from the roofs. This
system of water-supply has been always found to be pure and
The mineral oil used for the burners is not stored in bulk in
tanks, but in its original tins and cases in specially isolated oil
All the buildings in the Chinese light-houses are erected at some
THE CHINESE LIGHTHOUSE SERVICE. 95
distance from the towers, in order that the latter may not suffer
in case of a fire occurring in any of the quarters.
5. The more important coast lights are in charge of foreign
keepers, whose pay ranges from about ,18 to ^9 a month. The
river lights are manned by native keepers, whose monthly pay
ranges from $ 155. to 158.
6. Whistling, bell, and ordinary buoys are in use, and a WighanVs
buoy light has been experimented with. A considerable number
of gas buoys' on Pintsch's system, are now under order, and should
be watching early next year.
Portland cement concrete sinkers are now being used to moor
the buoys with, and are found to be very economical. Buoys and
beacons are all coloured on a uniform system.
7. The paper concludes with a description of the management
of the service, at the head of which is Sir Robert Hart, Bart.,
G.C.M.G., the Inspector-General of Chinese Customs. The
engineering is carried out by an engineer-in-chief, assistant
engineer, and staff, and the hydrographical and surveying work is
under the control of a coast inspector, the latter and the engineer-
in-chief working in consultation regarding the selection of sites
for lighthouses, etc.
There are at present 98 lighthouses, 4 light-vessels, 20 light-boats,
88 buoys, and 78 beacons under the management of the service,
besides 17 lights on the coast in the hands of foreign nations.
The Discussion was combined with that of the papers by Mr.
D. A. Stevenson, Baron Quinette de Rochemont, and Mr. Brebner
(see p. 97).
The author replied, and on the motion of the Chairman a vote
of thanks was accorded to him.
"IMPROVED RAPID GROUP-FLASHING LIGHTS."
Paper by ALAN BREBNER.
THE paper describes the combination of a complete subdivided
eclipsing screen of two or more parts, with a revolving optical
apparatus of two or more panels, by means of which group-flashing
lights can be produced in greater power and compactness than by
any other means. In this system a bivalve apparatus carries a
screen of two sub-divisions, a trilateral apparatus one of three sub-
divisions, and so on, each screen sub-division being attached to
and revolving with its corresponding lenticular panel. One burner
at che common focus of the lenses suffices for each complete
apparatus. The principle of the French " lightning light " is
absorbed by and perfected in this system. The trilateral form of
optical apparatus is shown to possess advantages over any other
form in r aspect of power and economy a fact first brought to
light by the author in 1890. Any one of the bivalve, trilateral,
quadrilateral, or other polygonal arrangements of the optical
apparatus, combined with the suitable eclipser, can give all the
group-flash characteristics; whereas with the Hopkinson system or
with the plain lightning-light system the number of panels must be
at least 2, 3, 4, 5, or 6 for the 2ble., 3ple., 4ple., 5ple., or 6ple.
No mirrors being required in the system described, opaque
as well as transparent luminaries can be fully utilised.
An example of a quadruple-flash characteristic obtainable from
a trilateral apparatus, making one revolution in 6 seconds, with a
burner of reasonable and current dimensions, is as follows : -
Flash, .1 sec.; eclipse, 1.9 sec.; flash .1 sec.; eclipse, 1.9 sec.;
flash, .1 sec.; eclipse, 1.9 sec.; flash, .1 sec.; eclipse, 5.9 sec. the
total period being 12 seconds.
Although the paper does not dwell on this fact, the system
makes it possible to produce such rapidly-delivered characteristics
as the following, if the persistence of luminous impressions be taken
into account: Flash, .25 sec.; eclipse, .25 sec.; flash, .25 sec.;
eclipse, .25 sec.; flash, .25 sec.; eclipse, .25 sec.; flash, .25 sec.;
eclipse. .75 sec.; the total quadruple-flash period being only 2\ sec.
Similarly the double and triple group-flashes could be given in
il, and 2 seconds, and so on.
IMPROVED RAPID GROUP-FLASHING LIGHTS. 97
The paper is illustrated by a sheet of drawings, and a drawing
and model of an optical apparatus, complete with eclipsing mechan-
ism, were shown at the meeting.
A combined Discussion was held on the papers by Mr. D. A.
Stevenson, Baron Quinette de Rochemont, Mr. Harding, and Mr.
Brebner, and was taken part in by the following members:
M. Ribiere, Mr. J. R. Harding, Mr. C. A. Stevenson, the Chairman,
and Mr. N. G. Gedge. The author replied by correspondence.
On the motion of the Chairman a vote of thanks was accorded
to the author.
On the motion of the Chairman a vote of thanks was accorded to
the Honorary Secretary, Prof. Vernon-Harcourt, and on the motion
of Baron de Rochemont a vote of thanks was accorded to the Chair-
man, Sir John Wolfe Barry, and to the Committees of the Congress.
The Chairman briefly replied.
The proceedings then terminated, and the business of the Section
was brought to a close.
SUMMARY OF PROCEEDINGS
Section III. Mechanical.*
TUESDAY, 3rd SEPTEMBER, 19O1.
Mr. WILLIAM H. MAW* in the Chair.
The Chairman opened the Proceedings with a few remarks.
"THE COOLING OF THE CYLINDERS OF HIGH-SPEED
INTERNAL COMBUSTION ENGINES, AND ITS
EFFECT UPON THE POWER DEVELOPED."
Paper by Professor H. HELE-SHAW, LL.D., F.R.S.
THE author commenced by giving his experience with the cooling
of small internal-combustion engines for motor cars, and explained
a method by which he had applied water cooling by gravitation to
a voiturette with extremely satisfactory results. He mentioned that
both with the voiturette in question and with a motor tricycle the
water on a hot day during a long run is for considerable periods
at a time on the boil without the power in any way appearing
to diminish ; whereas, on the other hand, he had been on larger
cars where owing to the defective working of the pump, the water
was not circulating properly, and a considerable amount of steam
was being formed. In the latter cases the power fell off in a very
serious manner; although the engines never actually stopped, as
has been seen with air-cooled motors.
Amongst those who are accustomed to drive motor cars there
is generally a feeling that the engines work best at a certain
temperature, somewhere between that at which the water boils off
and the cold state in which the engine actually starts. The author
* The full Proceedings of Section III., being Part IV., 1901, of the Pro-
ceedings of Mechanical Engineers, are published by the Institution of
Mechanical Engineers, Storey's Gate, St. James's Park, Westminster,
London, S.W. Price 45. post free.
COOLING OF THE CYLINDERS OF HIGH SPEED ENGINES.
was not able to find that there existed any actual data upon this
subject, and it seemed to be a sufficiently important matter to be
worth making some experiments upon. He has, therefore, with
the assistance of Mr. Gill, JB.Sc., engineering student of the Uni-
versity College of Liverpool, experimented upon a 6 H.P. engine.
This engine, which has magneto-electric ignition, was fitted with
two thermometers, measuring the temperature of the water at
entrance and at exit. A tank was used when the water was allowed
to remain at boiling point; but otherwise the two pipes were con-
nected with the mains, and the water at exit kept at the temperature
required by allowing a sufficiently rapid flow of water through the
cylinder-jacket The power was accurately measured by means of
a dynamometer brake acting on a flywheel. A series of five trials
were made, four with the water at different temperatures, and a
fifth with glycerine circulating in the cylinder-jacket and tank instead
of water, in order to obtain a higher boiling point and a higher
temperature of the cooling liquid.
The general result of these trials is given in the following table.
The two series of boiling-off experiments have been kept separate
from the other three, but the plotted results indicate the same
general result :
Summary of Tests.
1 66-2 77-0
In experiments i, 2, and 3, the water was running through.
In experiment 3 only a small quantity was allowed to flow, as it
\vas complete])'- evaporated.
Xos. 4 and 5 were boiling-off experiments.
100 COOLING OF THE CYLINDERS OF HIGH SPEED ENGINES.
The general nature of these experiments is immediately obvious,
and indicates a falling off in brake horse power as the temperature
rises, the brake horse power between the two extremes of tempera-
ture having fallen from 4.775 to 3-93? a diminution of about 17
Each series of experiments represents, roughly speaking, about
ten observations, which were conducted as carefully as possible;
but, at the same time, the difficulties of maintaining uniformly the
temperature and speed of the engine were sufficiently great to make
it undesirable to attempt to produce any mathematical statement
from these results. Further and more elaborate experiments will
be required, taking temperature in conjunction with the actual
quantity of water used, before any definite conclusion can be arrived
at on this subject. It is interesting to note that Mr. Dugald Clerk,
in reply to a letter from the author asking for information, appears
to have obtained, with a slow-running gas engine, slightly greater
efficiency at the higher temperatures ; but, of course, the foregoing
experiments only deal with actual power, and not with efficiency.
The author has not attempted to discuss the actual cause or
causes of the falling off in power as the temperature of the cylinder
rises. Whether this is due to lubrication difficulties or thinning
of the cylinder lubricant to a point which allows the piston rings
to leak, or whether due to heating of incoming charge and con-
sequent weakening of the mixture, would afford matter for an
The advances in the construction of these high-speed internal-
combustion engines, and the rapidly increasing power which is being
evolved from them, warrant their careful study. Thus, in the recent
Paris-Berlin race, there were several engines upon light motor
vehicles, capable of developing more than 50 H.P., with in one case
at least a weight of not more than 10 Ibs. per horse power. When
it is remembered that this is not merely the equivalent of the
steam engine, but of the engine and boiler, it will no doubt be
admitted that any point, such as the cooling of the cylinders, which
is an essential feature of the problem, is worthy of the attention of
The following members took part in the Discussion : Mr. Bryan
Donkin, Herr R. Diesel, Mr. Blackwood Murray, Mr. Dugald Clerk,
and the Chairman.
The author replied, and on the motion of the Chairman a vote
of thanks was accorded to him.
"TRIALS OF STEAM TURBINES FOR DRIVING
Paper by the HON. CHARLES A. PARSONS, F.R.S., and
GEORGE GERALD STONEY.
THE earlier forms of steam turbines were described in a paper
read before the Institution of Mechanical Engineers in 1888, but
since that date great improvements have been made both in the
design and construction leading, especially in the case of large
condensing turbines, to a very remarkable degree of economy.
Prior to 1890 all the steam turbines constructed were of the
non-condensing type of small size, but in 1892 one of 100 kws. was
constructed for condensing. With a steam pressure of 100 Ibs.
per square inch, and moderate superheat, a steam consumption of
27 Ibs. per kw. hour was obtained by Professor J. A. Ewing, F.R.S.,
a result rivalling the performances of the best compound recipro-
cating condensing engines.
This result placed the steam turbine among the most economical
means of obtaining electric energy from steam, and led to its
adoption in the lighting stations of Cambridge, Scarborough, New-
castle, and other places.
About two years later considerable improvements were intro-
duced, the single flow type of turbine being adopted, in which the
steam passes parallel to the axis, with balancing pistons to take
up the end pressure; these alterations both improved the economy
and also decreased the amount of workmanship involved. At the
same time the steam vanes or blades were strengthened and im-
The following performances in condensing turbines with saturated
steam of 140 Ibs. per square inch pressure were recorded; a 24
kilowatt plant gave 28.8 Ibs. per kw. ; a 50 kw., 28 Ibs. per kw. ;
a 100 kw., 26.4 Ibs. per kw. ; a 200 kw., 24.2 Ibs. per kw. ; and a
500 kw., 22.7 Ibs. per kw. With a moderate superheat of 50 deg.
F. these results are improved by about 8 per cent. ; and with
100 deg. F., by about 12 per cent.
With two 1000 kw. turbo alternators for the City of Elberfield,
with 140 Ibs. steam pressure, and about 25 deg. F. of superheat,
driving their own air pumps, the following remarkable results were
obtained on the official trials:
Load in kws 1250 1000 750 500 520
Lbs. steam per kw. hour 19.0 20.2 22.0 25.1 33.6
102 TRIALS OF STEAM TURBINES FOR DRIVING DYNAMOS.
It should be pointed out that, as there is no internal lubrication
in the steam turbine, there are none of the usual difficulties attend-
ing the use of superheated steam, and also that the water from the
hot-well is absolutely free from oil, and therefore can be used direct
in the boilers.
As might be expected, non-condensing turbines do not give such
high results, but with about 130 Ibs. steam pressure 39 Ibs. per kw.
has been obtained in a 100 kw. plant, and 38 Ibs. in a 250 kw. plant,
In larger sizes of, say, 1500 kw., with 200 Ibs. steam pressure
and 150 deg. F. superheat, a consumption of 28 J Ibs. per kw. non-
condensing has been guaranteed, and is expected to be easily
obtained, if not surpassed.
The following members took part in the Discussion : the Chair-
man, Professor Schroter, Professor William Ripper, and Mr. Bryan