IMPROVE- MENTS IN MAST-HEAD LIGHTS, LANTERNS, OR LAMPS
Year: 1870

page_text: LETTERS PATENT to James Hosken, of No. 58, Fenchurch Street,
in the City of London, Engineer, for the Invention of "IMPROVE-
MENTS IN MAST-HEAD LIGHTS, LANTERNS, OR LAMPS."
Scaled the 31st December 1870, and dated the 1st July 1870.
PROVISIONAL SPECIFICATION left by the said James Hosken at the
Office of the Commissioners of Patents, with his Petition, on the
1st July 1870.
I, JAMES HOSKEN, of No. 58, Fenchurch Street, in the City of
London, Engineer, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN MAST-HEAD LIGHTS, LANTERNS, OR LAMPS," to be as
follows:-
This Invention has for its object improvements in mast-head lights,
lanterns, or lamps, and it is designed for the purpose of shewing more
powerful and efficient mast-head lights than heretofore usually obtained
directly ahead and on either side and also abaft the beam of vessels, or,
in other words, over a range of more than one half of the compass, or
one half of the circumference of a circle.

page_text: The regulations made by the "Board of Trade" regarding mast-head
lights provide that the mast-head light of a vessel shall be visible at
what is technically termed two points abaft the beam of every vessel on
either side of her. In order to comply with the requirements of this
and other similar cases in the most efficient manner I, according to
my Invention, construct and arrange the mast-head light, lantern, or
lamp with a reflector or reflectors so contrived as to reflect and refract
the rays of light from the burner or burners in such a manner as to
throw positive rays of light from the reflector or reflectors over a range
of more than one half the circumference of a circle.
In carrying out my Invention as applied to mast-head lights, lanterns,
or lamps having only one burner and one reflector, I prefer to make the
reflector convex laterally, and concave vertically, and where two or more
burners are usod I by preference make the reflectors concave, but it will
be obvious that the number, form, and arrangement of the burners and
reflectors may be more or less modified without departing from the
principle of my Invention.
This Invention will be found of great value in preventing collisions
at sea, especially in hazy or foggy weather, when it would be difficult if
not impossible to discern any mast-head light from abaft the beam of a
vessel provided with a mast-head light, lantern, or lamp of the ordinary
kind as now generally in use.
SPECIFICATION in pursuance of the conditions of the Letters Patcut,
filed by the said James Hosken in the Great Seal Patent Office
on the 31st December 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
HOSKEN, of No. 58, Fenchurch Street, in the City of London, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of July, in the year of
our Lord One thousand eight hundred and seventy, in the thirty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said James Hosken, Her special licence that I,
the said James Hosken, my executors, administrators, and assigns, or

page_text: such others as I, the said James Hosken, my executors, administrators,
and assigns, should at any time agree with, and no others, from time
to time and at all times thereafter during the term therein expressed,
should and lawfully might make, use, exercise, and vend, within the
United Kingdom of Great Britain and Ireland, the Channel Islands,
and Isle of Man, an Invention for "IMPROVEMENTS IN MAST-Head Lights,
LANTERNS, OR LAMPS," upon the condition (amongst others) that I, the said
James Hosken, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should
particularly describe and ascertain the nature of the said Invention,
and in what manner the same was to be performed, and cause the same
to be filed in the Great Seal Patent Office within six calendar months
next and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said James Hosken, do hereby declare
the nature of the said Invention, and in what manner the same is
to be performed, to be particularly described and ascertained in and by
the following statement thereof (that is to say) :-
This Invention has for its object improvements in mast-head lights,
lanterns, or lamps, and it is designed for the purpose of shewing more
powerful and efficient mast-head lights than heretofore usually obtained
directly ahead and on either side and also abaft the beam of vessels,
or, in other words, over a range of more than one half of the compass,
or one half of the circumference of a circle.
The regulations made by the "Board of Trade" regarding mast-head
lights provide that the mast-head light of a vessel shall be visible at
what is technically termed two points abaft the beam of every vessel
on either side of her. In order to comply with the requirements of
this and other similar cases in the most efficient manner I, according
to my Invention, construct and arrange the mast-head light, lantern,
or lamp with a reflector or reflectors so contrived as to reflect the rays
of light from the burner or burners in such a manner as to throw
positive rays of light from the reflector or reflectors over a range of
more than one half the circumference of a circle.
In carrying out my Invention as applied to mast-head lights, lanterns,
or lamps having two or more burners, I make the reflectors concave,
but it will be obvious that the number, form, and arrangement of the
burners and reflectors may be more or less modified without departing
from the principle of my Invention.

page_text: In my Provisional Specification I stated that in carrying out my
Invention as applied to mast-head lights, lanterns, or lamps having
only one burner and one reflector I preferred to make the reflector
convex laterally, and concave vertically, but since then I have found
that the use of such reflectors as last described will not in practice give
the satisfactory results I then anticipated, because by reflectors of
that kind the rays of light are expanded and diminished in quality,
whereas, in order to obtain a thoroughly efficient mast-head light, I
have found it necessary to concentrate, and thereby intensify, the rays
of light over the entire range to be lighted.
This Invention will be found of great value in preventing collisions
at sea, especially in hazy or foggy weather, when it would be difficult
if not impossible to discern any mast-head light from abaft the beam
of a vessel provided with a mast-head light, lantern, or lamp of the
ordinary kinds as now generally in use.
And in order that the manner of performing my said Invention may
be fully understood I have hereunto annexed a Sheet of Drawings, in
which Fig. 1 is a side elevation, and Fig. 2 is a plan view in section
through the line A, B, of Fig. 1, shewing a mast-head light, lantern, or
lamp constructed according to my Invention.
a is an ordinary ship's lantern or lamp, provided as usual with a
suitable glass b and a lamp c. This lamp slides into the lantern a,
through a door at its back in the ordinary way, and has two sets of
burners, each set consisting of two burners d and e, situated at right angles
to one another, as shewn in Fig. 2. Behind these burners I place
the concentrating reflectors f and g, which, as will be seen, are made
concave in both directions, that is to say, laterally and vertically, and
are so placed with regard to their respective lights that the centres
of the flames, measured vertically, are situated in the same horizontal line
as the corresponding centres of the reflectors, which arrangement gives
better results than any other I have tried. The two reflectors may
be made of copper with burnished silvered faces, or of other suitable
reflecting material, and may be soldered or otherwise attached together
at h, so as to form practically one reflector, and in the lamp I have
illustrated the reflectors are provided with a small hook or bracket i,
fitting into a small socket k formed on the lamp for the purpose of
holding the reflectors in their proper respective positions.

page_text: It will be seen on reference to Fig. 2 that by the construction and
arrangement of the burners and reflectors as there shewn the rays of
light from the burners are concentrated and reflected in a positive and
direct manner, so as to produce a powerful concentrated light over a
range of more than half the circumference of a circle.
Altho I have illustrated my Invention as applied to an oil lamp
it will be obvious that my Invention is equally applicable to mast-head
lights, lanterns, or lamps in which candles or other illuminating media
are used, also that instead of constructing the apparatus as shewn to throw
the concentrated rays of light only two points abaft the beam of a vessel
on either side of her, as provided by the Board of Trade regulations, the
construction and arrangement may be readily modified, so as to throw
such rays of light over a greater or less area, without departing from the
principle of my Invention.
And having now described the nature of the said Invention, and in
what manner the same is to be performed, I hereby declare that I do
not claim separately as parts of my Invention any of the several parts
above described or referred to, but what I do claim and desire to be
secured to me by the herein-before in part recited Letters Patent
is,-
Firstly. Constructing mast-head lights, lanterns, or lamps so as to
throw concentrated rays of light from their reflectors over a range of
more than one half the circumference of a circle.
Secondly. The combination of the several parts forming the improved
mast-head light, lantern, or lamp, constructed and arranged substantially
as herein-before described and shewn in the annexed Drawings, or any
mere modification thereof.
In witness whereof, I, the said James Hosken, have hereunto set
my hand and seal, this Thirty-first day of December, in the
year of our Lord One thousand eight hundred and seventy.
JAMES HOSKEN. (L.S.)