Improved Portable Sun Dial Mean-time Indicators.
Year: 1896

page_text: Date of Application, 19th Aug., 1896-Accepted. 17th Oct., 1896
COMPLETE SPECIFICATION.
Improved Portable Sun Dial Mean-time Indicators.
I, JOSÉ PANE, of Mayor 15, Lerida, Spain, Watch Maker, do hereby declare the
nature of this invention and in what manner the same is to be performed to be
particularly described and ascertained in and by the following statement:-
This invention relates to improved portable sun dial mean-time indicators.
It is well known that the true solar time is very irregular for the setting of
mechanical watches, therefore especial rules had to be established in order that
sun dials could be used for this purpose.
Tending to this object there are tables of equations, by the aid of which the
difference between the true but irregular time and the mean uniform time of each
day, is known; these tables. are excellent for the regulation or adjusting of
mechanical watches; but are not of general use for reasons that it is not necessary
bore to explain, and on the other hand the sun dials cannot be used without them,
because the meridianal altitude of the sun varies from day to day and month to
month, for these reasons the ordinary mechanical watches however exact they be,
may without a reliable means of comparison for regulation give wrong indications
of time; from all these causes, the want of a simple and practical means for
regulating and adjusting timepieces other than by comparison with a mechanical
chronometer has been greatly felt.
The new system which will be duly described fills all the requirements of a
good time regulator and is represented in two different forms in the following
diagrams:
Figure 1, round sun dial.
Figure 2, style or index pointer.
Figure 3, vertical suspension sun dial with style c.
In order that the invention as shown in the drawings may be thoroughly under-
stood I here explain the principles upon which my improved sun dial is based, it
is well known that the meridianal altitude of the sun varies for any given hour as
the days go by and the degree of such variation is ordinarily compensated for by
the use of known astronomical equation tables expressly worked out for this
purpose but in my improved sun dial shown in Figure 1, the variation of the sun's
altitude is worked out geometrically for a given hour for every day of the year,
consequently when the extreme point of the Gnomon's shadow coincides with the
dot particular to the day of the month on which the observation is made it is
known that the particular hour for which the sun dial bas been set out has arrived,'
and so on for every day of the year without the use of any tables whatever. The
sun dial must of course be worked out to suit different parallels and may also be
made to suit different hours.
The instrument represented in Figure 1 consists of a disc or plato having a hole
in the centro for the adaptation of the style b, Figure 2, which at the same time.
may be used for suspending the instrument, the shadow cast by the point or und
of the style marks the hours of mean-time.
The instrument shown in the diagram marks the eleventh hour of the solar day.
Each of the points or dots of the dotted spiral line distributed on the surface of
both halves of the plate only one half of which represents the same hour for every
day of the year, the day of the month to which they correspond being marked
on the circumference and the name of the month by the initial letter on the.
respective spirals.

page_text: In order to find the dot or hour corresponding to the day of the particular
month on which the observation is taken, it is only necessary to look for its initial
letter in those marked one after the other starting from the point where the spiral
begins, to this purpose on each face of the plate or disc there are marked
six months; the drawing indicates only the six corresponding to July, August,
September, etc.
The use of this sun dial is perfectly easy, Figure 1 is simply proferably laid
horizontally upon an even surface, or it is suspended from any suitable support
with a thread a by its style in the manner shown in the diagram, Figure 2.
The instrument being so fixed, is then turned round until the shadow of the style
falls upon the radial line corresponding to the date of the observation, as 8000 as
the extreme end or point of Gnomon's shadow coincides or falls directly upon the
dot relating to the day of the required month, the observer finds the exact hour
object of the observation, say 11 a.m.
With the use of these instruments, there is no necessity of solving equations, or
of making calculations of any sort, since the instrument itself indicates directly
the mean-time's hour; notwithstanding this, I think it to be useful, to indicate the
equations on the instruments. Those who desire to calculate them every day will
have only to observe in the afternoon when the shadow passes over the same point
corresponding to the morning's observation, the observer can then compute tbe
lapse of time between the two passes and the mean proportion of what is wanting
or exceeding of the two hours, is equal to the equation.
The other instrument consists in a plate of vertical suspension indicating ono or
more hours. On the instrument shown on the drawing, there may be observed
two hours of mean-time, eleven and one o'clock and also the period of passage of
the sun through the true meridian viz.: 12 o'clock noon. The small dimensions of
this instrument do not allow it to indicate these hours viz.: 11-noon-and I o'clock
every day but every ten days, but if it were made of larger dimensions it would
mark them more frequently. These instruments may be constructed of different
dimensions, and it will be easily understood that the larger the latter are, less
commodious is the handling of the same, on the other hand their precision is
rendered much greater.
On the surface of all these instrumente, the hours are marked with dots in the
same manner as in the round dials but in different order.
When making observations the first thing to be done is to find the day and
month corresponding to the date of observation which day is found by looking at
the instrument, thereon being marked the names of the months or their initial
letters in their consecutive order, the days are also marked near the dots that
represent them; for the sake of comprehensibleness the dates at each of the dots
of the smaller instruments are not indicated but which are easily understood as
they represent intervals of ten days.
The first observation is to be preferably made on the 10th of each month if the
instrument is not larger than the one shown by the diagram Figure 3, as these
days correspond to the dots. Excepting from this rule the months of January
and July whose observation can be made on the 1st day of the month as by the
instrument shown these dates are marked. The last observation can be taken
preferably on the 30th of each month, with the exception of February, June, and
December which is to be on 28th for the first named month, and on the 20th for
the last two as these are the last dates for which the instrument is marked.
These rules are not of strict adoption, as other dates may be chosen without
fear of committing an error, but of course. always as per indication of each
instrument.
It is to be observed that each dotted line serves only for one particular hour.
Figure 3 shows three dotted lines, the two laterals mark 11 and 1 o'clock, and
the middle one indicates the hour of passage of the sun through the true
meridian.
By the above specification it will be easily understood the construction of the

page_text: apparatus and the way to use it. Its use, as has before been mentioned, is very
simple, the only thing to be done is to suspend or fix it with its divided surface in
a horizontal position in one case and vertically in the other, and that in the case
of the circular style's shadow is directed to the radial line containing the dot
corresponding to the date of the observation as soon as the point of the shadow of
the index coincides with the point in question it marks the hour sought by the
observer, and to this hour the timepiece to be tested is set and after an interval of
some hours or it may be days or even months the same process is gone through
and the timepiece compared with the sun dial the instant the point of the
Guomon's shadow coincides with the dot of the day of the month, and if found.
fast or slow can be adjusted accordingly.
This is the description of the apparatus, the only thing that has to be added is
that cach side surface of the instrument indicates only six months.
As regards the circumstance of not marking the hour every day in the case of
Figure 3, this slight deficiency is of little importance considering that the main
object of the instrument is the regulation of watches as a few days more or less is
of little account. Apart from these considerations it is well known that in order
to ascertain the discrepancy of a watch, a few daya must elapse between the two
observations.
Considering the want of accurate indicating instruments for the regulation of
mechanical watches, the usefulness of the new invention will be easily understood,
moreover the two different forms of the instrument united with the uot less.
important advantage that they may have any suitable dimensions, makes them fit
for their application to all parallels.
Having now particularly described and ascertained the nature of this inven--
tion and in what manner the same is to be performed I declare that what I
alaim is :-
1. The new construction of sun dial constructed in two different forms,.
viz.: one consisting in a round plate or disc disposed horizontally and provided
with a style 6 at its centre, and on each half surface or side with a dotted spiral
line so divided that each of its turns corresponds to a month, and the numbers
marked near the periphery indicate the respective days of the said space of time,
by this means the hour of mean-time is easily found by only observing the arrival
of the style's shadow to the point corresponding to the day of the observation, as
set forth.
2. The sun dial consisting of a vertical plate having at its top part a style c.
and provided on each half face with dotted lines, which looked at in horizontal
direction correspond to the days duly marked of each month, and in the vertical
direction indicate the hours of mean-time at the dots that form the lateral lines,
and on the central line it indicates the pass of the sun through the true meridian
the entire iudication being performed by the shadow's end cast by the style, as
described.
Dated this 19th day of August 1808
H. GARDNER,
Patent Agent, 166 Fleet Street, London,.
Agent for the said Jose Pané.