f any
observation, in order that he may assign to any spot or set of spots its
true position in relation to solar longitude and latitude. Mr. Howlett
shows how this may be done by three observations of the sun made at any
fixed hour on successive days. Perhaps the following method will serve
the purpose of the general observer sufficiently well:--

The hour at which the sun crosses the meridian must be taken for the
special observation now to be described. This hour can always be learnt
from 'Dietrichsen's Almanac'; but noon, civil time, is near enough for
practical purposes. Now it is necessary first to know the position of
the ecliptic with reference to the celestial equator. Of course, at noon
a horizontal line across the sun's disc is parallel to the equator, but
the position of that diameter of the sun which coincides with the
ecliptic is not constant: at the summer and winter solstices this
diameter coincides with the other, or is horizontal at noon; at the
spring equinox the sun (which travels on the ecliptic) is passing
towards the north of the equator, crossing that curve at an angle of
23-1/2 deg., so that the ecliptic coincides with that diameter of the sun
which cuts the horizontal one at an angle of 23-1/2 deg. and has its _left_
end above the horizontal diameter; and at the autumn equinox the sun is
descending and the same description applies, only that the diameter
(inclined 23-1/2 deg. to the horizon) which has its _right_ end uppermost,
now represents the ecliptic. For intermediate dates, use the following
little table:--

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Date. |Dec. 22|Jan. 5|Jan. 20|Feb. 4|Feb. 19|Mar. 5 |Mar. 21
(Circiter.) | |June 6|May 21 |May 5 |Apr. 20|Apr. 5 |
-------------------+-------+------+-------+------+-------+-------+--------
Inclination of |Left |Left |Left |Left |Left |Left |Left
Ecliptical Diameter| | | | | | |
of Sun to the |0 deg. 0' |6 deg.24' |12 deg.14' |17 deg.3' |20 deg.36' |22 deg.44' |23 deg.27'
Horizon.[17] |Right |Right |Right |Right |Right |Right |Right
-------------------+-------+------+-------+------+-------+-------+--------
Date. | |Dec. 7|Nov. 22|Nov. 7|Oct. 23|Oct. 8 |
(Circiter.) |Jan. 21|July 7|July 23|Aug. 6|Aug. 23|Sept. 7|Sept. 23
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