AN IMPROVED INSTRUMENT FOR DETERMINING THE ALTITUDE AND ZENITH. DISTANCE OF CELESTIAL BODIES
Year: 1870

page_text: LETTERS PATENT to William Robert Lake, of the "International
Patent Office," Southampton Buildings, London, Consulting Engineer,
for the Invention of "AN IMPROVED INSTRUMENT FOR DETERMINING THE
ALTITUDE AND ZENITH. DISTANCE OF CELESTIAL BODIES."-A communi-
cation from abroad by Hall Colby, of the City and State of New
York, United States of America.
Scaled the 5th April 1870, and dated the 17th February 1870.
5
COMPLETE SPECIFICATION filed by the said William Robert Lake
at the Office of the Commissioners of Patents, with his Petition and
Declaration, on the 17th February 1870, pursuant to the 9th Section
of the Patent Law Amendment Act, 1852..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WILLIAM
ROBERT LAKE, of the "International Patent Office," Southampton
Buildings, London, Consulting Engineer, send greeting.
WHEREAS I am in possession of an Invention for "AN IMPROVED
INSTRUMENT FOR DETERMINING THE ALTITUDE AND ZENITH DISTANCE OF CELESTIAL

page_text: BODIES," and have petitioned Her Majesty to grant unto me, my
executors, administrators, and assigns,. Her Royal Letters Patent for the
same, and have made solemn Declaration that it has been communi-
cated to me from abroad by Hall Colby, of the City and State of New
York, United States of America..
NOW KNOW YE, that I, the said William Robert Lake, do hereby
declare that the following Complete Specification, under my hand and
seal, fully describes and ascertains the nature of the said Invention, and
in what manner the same is to be performed, in and by the following
statement, reference being had to the accompanying Drawing forming 1
a part of this Specification..
The nature of my Invention consists in the peculiar construction,.
combination, and arrangement of the several parts of the instrument.
herein-after fully described, the same to be used for taking altitudes
or observations of the sun, moon, or stars, for the purpose of determining 1
latitude on sea or land, as herein-after set forth.
Figure 1 is a side
or graduated side.
Figure 3 is a rear
DESCRIPTION OF THE DRAWING..
elevation of my improved instrument, on the front
Figure 2 is a section of the stop lock or catch...
side elevation of the said instrument, and Figure 4 2
is a transverse vertical section. The same letters of reference indicate
the same parts in the several Figures. G, marks the segmental frame
of the instrument, to the rear side of which is attached a handle J
whereby the instrument is held while taking an observation. On.
the upper part of the frame G is placed the horizon plate b having 2
a spirit level P attached, and above the plate b is the telescope formed
in two tubular sections a, a², of which a is the eye glass and a²
the object glass. On the perimeter of the frame G is a flange G¹
graduated in the manner represented, the lowest or nadir point being
marked 0 (zero) and the arc graduated to 90° or more in both directions 3
as shown in Figure 1. On an axis c which coincides with the centre
of the are G¹ is suspended (so as to have free movement) what I deno-
minate a graduated double vernier balance A. This is an arc of a little
more than 90° graduated on its edge as shown, and so weighted that
the arrow marked upon it (see Figure 1) will always be in the lowest 3
position when the arc is allowed to gravitate freely. To prevent
excessive oscillation while allowing free gravitation the springs d, d,

page_text: دل
attached to the cord e passing around the pulley & attached to the
rear of the balance A operate to check the too sensitive movement
of the balance. On each end of the balance A is a vernier, the lower
one being the altitude vernier, and the upper one g¹ placed at 90°
from the other the zenith vernier. The zero at the altitude vernier
coincides with the zero or nadir point of the arc G' when the zero of
the zenith vernier g' coincides with the 90° of the said arc. The verniers
are so graduated that 30 divisions on the vernier correspond to 29
divisions on the limb. The limb being graduated to degrees and half
degrees the verniers therefore read to minutes and half minutes. A stop
llock is attached to the lower side of the frame (see Figures 2 and 3).
To a stud o projecting downward from the frame G is pivoted a lever C
having the tooth n on the end of its short arm and a spring s reacting
against its longer arm to press it downwards. A notch on the end
of the long arm of the lever C engages with a spring trigger h controlled
by the spring i, the said trigger holding the long arm of lever C up
until the trigger is pulled back by the observer, when the spring s
bears down the long arm of C, and throws the tooth n up to engage
with a notch on the lower rim of the balance A, and arrest its motion
at any desired point or instant. The telescope or sighting apparatus.
is not provided with lenses but the eye tube a has double plates
with a small aperture, and the object tube has cross wires arranged at
right angles, their point of intersection coinciding with the axis of the
telescope. My instrument, as before observed, is for taking altitudes
or observations of the sun, moon, or any star, as may be required for the
purpose of determining latitude at sea or on land, dispensing with the
ordinary rules of dip, refraction, semi-diameter and parallax by reason
of the fixed plane or horizon enabling the observer to measure the altitude
of any celestial body in its actual position without reduction to the
natural horizon. My instrument it will be perceived by means of the
balance A has a range from a horizontal plane to a zenith observation,
the altitude and zenith verniers being 90° apart, and the altitude and
zenith are readily and correctly read off on either limb for f¹ of the
are from 0° right or left. The zenith distance being what the altitude
of the object wants of 90° what is not indicated as altitude on vernier g
will be read as zenith on venier g'. The peculiar construction of the
telescope obviates refraction and the cross, lines enable the observer to
get the centre of the observed body.

page_text: Having thus fully described the said Invention as communicated to
me by my foreign correspondent I claim,―
First. The instrument for determining at the same time both the
altitude and zenith distance of celestral and terrestrial objects, the
same consisting of the arc G, horizon plate b, telescope a, a², and double
vernier balance A, in combination with the stop lock or catch, sub-
stantially as specified.
Second. The combination with the vernier balance A of a tension device
consisting of the springs d, d, cord e, and pulley d', substantially as
described.
In witness whereof, I, the said William Robert Lake, have here-
unto set my hand and seal, this-Seventeenth-day-of-February,-
in the year of our Lord One thousand eight hundred and
seventy.
WILLIAM ROBERT LAKE. (L.S.)
Witness
H. J. GEDGE,
Clerk to Messrs. Haseltine, Lake, & Co.