ng the time of greatest obscuration, the
extreme cusps of light produced by the intervention of the Moon would
still have stood at about 35 deg. 4', just 23' below the highest point of
light at noon (Fig. 12). _The whole disc of the sun had now risen above
the gnomon, yet no motion of the shadow on the steps had been observed
for fully five minutes. The time shown by the dial was seemingly
mid-day._

[Illustration: FIG. 12.--ECLIPSE OF THE SUN, JANUARY 11, 689 B.C., AT
JERUSALEM.]

Sun's apparent semi-diameter 16' 13"
Moon's " " 15' 13"
Moon's relative hourly motion in declination 5' 44" northward.
Right ascension, 29' 33" eastward.
Corrected for Jerusalem, 19' 42" eastward.
Altitude of the Gnomon, 34 deg. 41' 13".

SUN'S ALTITUDE BEFORE AND AT NOON.

[Illustration: Phase at 20 minutes before noon.]

[Illustration: Phase at noon.]

We have now to consider "to what extent would a staircase rising at an
angle of 31 deg. 47' towards the Sun, with a gnomon so placed at the top as
to cast a shadow to the foot of the lower step on the shortest day of
the year be affected by a movement in a perpendicular direction of the
point of light to the extent of 23', or 1/3 of a degree"? The effect would
be widely different at different times of the year, being greatest at
mid-winter when the shadows are longest, and least at mid-summer when
the shadows are shortest. It follows from this that January 13 being a
day but three weeks removed from mid-winter day the normal shadow would
be not far from its longest possible length, and the effect of a
displacement of 23' would be neither more nor less than 1/12th of the
whole range of the steps whatever that range might have been. This
extent of motion, then, is fully sufficient to satisfy the condition
prescribed by the Biblical narrative of there being such a deflection of
the Sun's light as would affect the shadow to the extent implied by the
words "ten steps" or "ten degrees," which is virtually the same idea.
The same extent of motion could not have been produced under the same
conditions either a few days earlier or a few days later; that may
certainly be taken for granted. And the only point in which we are
necessarily in doubt arises from the fact that we are ignorant of the
actual number and nature of the graduations of Ahaz's so-called "Dial."
If it were permissible to assume that there were 120 graduations on the
instrument, be they steps properly so-call