IMPROVEMENTS IN SHIPS SIGNAL LANTERNS
Year: 1857

page_text: LETTERS PATENT to John Henry Johnson, of 47, Lincoln's Inn Fields,
in the County of Middlesex, and of 166, Buchanan Street, in the City of
Glasgow, North Britain, Gentleman, for the Invention of "IMPROVEMENTS
IN SHIPS SIGNAL LANTERNS."-A communication from Hector L. Stevens,
of Washington, in the United States of America.
Sealed the 23rd March 1858, and dated the 23rd November 1857.
PROVISIONAL SPECIFICATION left by the said John Henry Johnson at
the Office of the Commissioners of Patents, with his Petition, on the
23rd November 1857.
I, JOHN HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of
Middlesex, and of 166, Buchanan Street, in the City of Glasgow, North
Britain, Gentleman, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN SHIPS' SIGNAL LANTERNS," a communication from Hector L.
Stevens, of Washington, in the United States of America, to be as follows:--
This Invention relates to a peculiar construction and arrangement of the
glasses or lenses of ships' lanterns, whereby the general course of a ship may
be defined by the aid of a single lantern in place of requiring three lanterns,
as is usually the case. The improved lantern may be fitted with dioptric, plain
glass, or round lenses, as may be found most desirable, and is intended to be
carried at the bowsprit cap. If the dioptric lens be used, the lamp will require
to be slung in gimbals, for the purpose of enabling it to assume a constantly

page_text: perpendicular position. The improvements consist in applying two colored
glass screens to the lantern, forming each an arc of about 90°; the ono screen
is green and the other red, whilst an open space of about 45° is left between
the front edges of the screens, so as to shew a clear white light a-head. By
this arrangement, it is obvious that a red, white, or green light will be seen
according to the ship's course and the point from which the light is viewed,
thus enabling the course of the ship to be defined with sufficient accuracy by
means of one lantern.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said John Henry Johnson, in the Great Seal Patent Office on
the 12th May 1858.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
HENRY JOHNSON, of 47, Lincoln's Inn Fields, in the County of Middlesex,
and of 166, Buchanan Street, in the City of Glasgow, North Britain, Gentle-
man, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-third day of November, in the year of our
Lord One thousand eight hundred and fifty-seven, in the twenty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said John Henry Johnson, Her special license that I, the said John
Henry Johnson, my executors, administrators, and assigns, or such others as I,
the said John Henry Johnson, my executors, administrators, or 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 "Iы-
PROVEMENTS IN SHIPS' SIONAL LANTERNS," a communication from Hector L.
Stevens, of Washington, in the United States of America, upon the condition
(amongst others) that 1, the said John Henry Johnson, by an instrument in
writing under my hand and seal, 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, tho said John Heury Johnson, do hereby
declare the nature of the said Invention, and in what manner the same is to

page_text: be performed, to be particularly described and ascertained in and by tho
following statement, reference being had to the accompanying Drawings, and
to the letters and figures marked thereon, that is to say :-
The said Invention relates to a peculiar construction and arrangement of the
glasses or lens of ships' lanterns, whereby the general course of a ship may be
defined by the aid of a single lantern in place of requiring three lanterns, as is
usually the case.
The improved lantern may be fitted with dioptric, plain glass, or round
lenses, as may be found most desirable, and is intended to be carried at the
bowsprit cap. If the dioptric lens be used, the lamp will require to be slung
in gimbals, for the purpose of maintaining it in a constantly perpendicular
position during the motion of the ship. The improvements consist in applying
two colored glass screens to the lantern, each screen forming an arc of
about 90°; the one screen is composed of green glass, and the other of red
glass (other colors may of course be used), whilst an open space of about 45°
is left between the front edges of the screens, so as to shew a clear white light
a-head. By this arrangement it is obvious that a red, white, or green light
will be seen, according to the ship's course and the point from which the light
is viewed, thus enabling the course of the ship to be defined with sufficient
accuracy by means of one lantern.
And in order that the said Invention may be fully understood, I shall now
proceed more particularly to describe the same, and for that purpose I shall
refer to the several Figures on the Sheet of Drawings hereunto annexed, the
same letters of reference indicating corresponding parts throughout both
Figures.
Figure 1 of the Drawings represents a front elevation of the improved
lantern complete, and Figure 2 is a corresponding sectional plan of the colored
glass screens and the back of the lantern. A and B represent respectively the
green and red colored glass screens, the green being in the "starboard" side,
and the red on the "port" or "larboard "side, each screen extending over
about 90° of the circle. They are separated by the white are C of about 45°,
which should face directly a-head, or in the direction of the vessel's course.
By the use of three colored glass screens, the general course of the vessel may
be defined by one lantern, in place of requiring three, as in the case of
steamers, according to regulation, Thus, if the view be from within two
points of abaft the port beam to two points of a-head, a red light will be
shewn by the lantern, and if from two points on the port bow to two points
on the starboard bow, a white light is seen, and from two points on the
starboard bow to two points abaft the beam, a green light is shewn.

page_text: It is obvious that the extra screens might be dispensed with, provided tho
lenses or the plain glass of the lantern be made of the required different colors,
the same result of three lanterns in one being equally obtained.
Having now described and particularly ascertained the nature of the said
Invention, and the manner in which the same is or may be used or carried
into effect, I would observe in conclusion that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as variations may be made therefrom without deviating
from the principles or main features of the said Invention; but what I consider
to be novel and original and therefore claim as the Invention secured to me by
the herein-before in part recited Letters Patent is, the application and
use of fixed colored screens or glasses to and in bowsprit cap lanterns,
such screens indicating respectively "port" and "starboard" sides, and
forming an arc of about 90° upon tho cylinder of the lantern, and separated
by an intermediate white glass or screen forming an arc of about 45°,
as herein-before described.
In witness whereof, I, the said John Henry Johnson, have hereunto set
my hand and seal, this Twelfth day of May, Oue thousand eight
hundred and fifty-eight.
J. HENRY JOHNSON.
(L.S.)