CERTAIN IMPROVEMENTS IN MARINERS' AND LAND COMPASSES
Year: 1855

page_text: LETTERS PATENT to Alexandre Tolhausen, of No. 7, Duke Street, Adelphi,
London, County of Middlesex, Sworn Interpreter at the Imperial Court
of Paris, for the Invention of "CERTAIN IMPROVEMENTS IN MARINERS'
AND LAND COMPASSES."-A communication from John Prime, Washington,
United States.
terpreter at the imperia
of Paris, for the Invention of "CERTAIN IMPROVEMENTS IN MARINERS'
AND LAND COMPASSES."-A communication from John Prime, Washington,
United States.
Sealed the 3rd June 1856, and dated the 11th December 1855.
PROVISIONAL SPECIFICATION left by the said Alexandre Tolhausen at
the Office of the Commissioners, of Patents, with his Petition, on the
11th December 1855.
I, ALEXANDRE TOLHAUSEN, of No. 7, Duke Street, Adelphi, London,
County of Middlesex, Sworn Interpreter at the Imperial Court of Paris, do
hereby declare the nature of the said Invention for "CERTAIN IMPROVEMENTS
IN MARINERS AND LAND COMPASSES," being a communication from John Prime,
Washington, United States, to be as follows:-
The object of these improvements is, 1°, to make the glass cover serve as
or form a perfectly water-tight protection to the compass bowl or box. In
compasses of the ordinary kind the glass is flat & 'fitted into a rebate formed
in the head of the bowl or box, & a close joint is made by the application
of putty to cover the edge of the glass. This is liable to the following. objec→
tions The frequent expansion & contraction of the box or bowl by changes
of atmospheric temperature soon cracks the putty, & the glass being a little

page_text: lower than the surrounding rim of the head, forms, as it were, a cup to receive
the rain, which soon works thro' the cracked putty into the bowl, & not only
damages the card, but when it is evaporated by exposure to the sun or the
heat of the atmosphere, it dims the glass frequently to such an extent as to
completely obscure the card. To obviate this, I make the glass in the form of
a cap with a rim to fit over the head of the bowl to shed off all the water; &
I protect the glass from being cracked by the expansion of the bowl by means
of a ring of elastic material placed between the head of the bowl & the rim of
the glass cap.
2d, to balance the compass card & needle, applicable only to the mariner's
compass, by attaching thereto a suitable number of rigid arms provided with
weights which screw or slide thereon to move them nearer to or farther from
the centre of suspension. By screwing or moving these weights to or from
the centre, as may be necessary, the card may be balanced accurately, & the
dip of the needle be at any time accurately compensated for.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Alexandre Tolhausen in the Great Seal Patent Office on the
5th June 1856.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, ALEXANDRE
TOLHAUSEN, of No. 7, Duke Street, Adelphi, London, County of Middlesex,
Sworn Interpreter at the Imperial Court of Paris, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eleventh day of December, in the year of our Lord
One thousand eight hundred and fifty-five, in the nineteenth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Alexandre Tolhausen, Her special licence that I, the said Alexandre Tol-
hausen, my executors, administrators, and assigns, or such others as I, the said
Alexandre Tolhausen, 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 "CERTAIN IMPROVE-
MENTS IN MARINERS' AND LAND COMPASSES," a communication from John Prime,
Washington, United States, upon the condition (amongst others) that I,
the said Alexandre Tolhausen, my executors or administrators, by an instru-

page_text: ment 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 Alexandre Tolhausen, do hereby declare
the nature of the said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement:
$
The object of one of these improvements is to make the glass cover serve as
or form a perfectly water-tight protection to the compass bowl or box. In
compasses of the ordinary kind the glass is flat and fitted into a rabbet formed
in the head of the bowl or box, and a close joint is made by the application
of putty to cover the edge of the glass. This is liable to the following objec-
tions-The frequent expansion and contraction of the box or bowl by changes
of atmospheric temperature soon cracks the putty, and the glass being a little
lower than the surrounding rim of the head, forms, as it were, a cup to receive
rain, which soon works through the cracked putty into the bowl, and not only
damages the card, but when it is evaporated by exposure to the sun or heat of
the atmosphere, it dims the glass frequently to such an extent as to 'completely
obscure the card. The improvement to obviate this consists in making the
glass in the form of a cap, with a rim to fit over the head of the bowl to shed
off all the water, and in protecting the glass from being cracked by the
expansion of the bowl by means of a ring of elastic material placed between
the head of the bowl and the rim of the glass cap.
Another improvement consists in a novel method of balancing the compass
eard and needle, applicable only to the mariners' compass.
.:
Fig. 1 is a central section of a mariners' compass constructed according to
my Invention; and Fig. 2, an inverted plan or under side view of the compass
card. Similar letters of reference indicate corresponding parts in both Figs.
A is the bowl or box; and B, a metal ring forming part of the head thereof,
the said ring fitting tightly over the top of the bowl so as to be capable of
removal when necessary. This ring is made with a slight recess in its outer
surface. C is the glass cap which is blown or otherwise formed with a rim to
fit over the ring B. Within the recess a a ring d of india-rubber, gutta
percha, wool, cotton, cloth, or any other elastic or yielding material is placed
between the ring B and the rim of the cap C, to prevent the expansion of the
said ring acting with sufficient force on the glass cap to crack or break it, and
the lower part of the joint formed by the metal ring B, elastic ring d, and

page_text: cap C is covered with putty, as shown at i, i, Fig. 1. The top of the glass
cap may be either flat or convex. It will be understood that rain or condensed
moisture falling or settling on the glass cap C, cannot by any possibility, so
long as the compass remains upright, find its way into the bowl but will be
shed or run off. D is the compass card, and E is the needle, which are
attached together and poised in the usual way upon a fine central point b
within the bowl. To the centre socket c, which is fitted to the point 6 and
supports the needle and card, are attached four arms e, e, e, e, standing at
equal distances apart. These arms are screwed and provided each with a nut
to serve as a balance weight, but they may be plain, and provided with
sliding weights fitted with springs so as not to move too easily. By screwing
or moving these weights to or from the centre, as may be necessary, the card
may be balanced accurately, and the dip of the needle at any time be accu-
rately compensated for.
Having thus described the nature and particulars of the said Invention, I
desire it to be understood that I do not confine myself to the precise details
herein described; but I claim as new and of my Invention,-
1st, making the glass of the compass with a rim to fit over the top or head
of the bowl, and providing a ring of any elastic or suitable yielding material
between the said rim and the head, whereby rain or other moisture settling
on the glass is prevented running into the bowl, and at the same time the
glass is protected against the expansion of the case, substantially as herein
set forth.
2nd, balancing the compass card and needle by attaching thereto a suitable
number of rigid arms e, e, provided with weights which screw or slide thereon
to move them nearer to or farther from the centre of suspension, substantially
as herein described.
In witness whereof, I, the said Alexandre Tolhausen, have hereunto sct
my hand and seal, this Fifth day of June, in the year of our Lord
One thousand eight hundred and fifty-six.
A. TOLHAUSEN. (L.S.)